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Rewriting the Genetic Code

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Rewriting the Genetic Code

DNA, or deoxyribonucleic acid, is at the root of all life as we know it. Using just four component nucleotide bases, DNA contains all the information needed to build any protein. To make a protein, DNA is transcribed into mRNA, which is in turn “translated” into a protein by molecules called ribosomes. More specifically, the mRNA is “read” by ribosomes in groups of three base pairs called codons, each of which codes for one of 20 possible amino acids. The set of rules that determines which codon codes for which amino acid is called the genetic code, and it is common to almost all known organisms--everything, from bacteria to humankind, shares the same protein expression schema. It is this common code that allows synthetic biologists to insert one organism’s genes into another to create transgenic organisms; generally, a gene will be expressed the same way no matter what organism possesses it. Interestingly, some scientists are attempting to alter this biological norm: rather than modifying genes, they are attempting to modify the genetic code itself in order to create genetically recoded organisms, or GROs.

This modification is possible due to the redundancy of the genetic code. Because there are 64 possible unique codons and only 20 amino acids found in nature, many amino acids are specified by more than one codon. Theoretically, then, researchers should be able to swap every instance of a particular codon with a synonymous one without harming a cell, then repurpose the eliminated codon.1 This was proven possible in a 2013 paper by Lajoie et al. published in Science; in it, a team of scientists working with E. coli cells substituted all instances of the codon UAG, which signals cells to stop translation of a protein, with the functionally equivalent sequence UAA. They then deleted release factor 1 (RF1), the protein that gives UAG its stop function. Finally, they reassigned the function of UAG to code for a non-standard amino acid (NSAA) of their choice.1

In a more recent paper, Ostrov et al. took this recoding even further by excising seven codons from the E. coli genome, reducing it to 57 codons. Because there are 62,214 instances of these codons in the E. coli genome, researchers couldn’t directly excise them from the E. coli DNA with typical gene-editing strategies. Instead, they resorted to synthesizing long stretches of the modified genome, inserting them into the bacteria, and testing to make sure the modifications were not lethal. At time of publishing, they had completed testing of 63% of the recoded genes and found that most of their changes had not significantly impaired the bacteria’s fitness, indicating that such large changes to the genetic code are feasible.2

Should Ostrov’s team succeed in their recoding, there are a number of possible applications for the resulting GRO. One would be the creation of virus-resistant cells.1,2,3 Viral DNA injected into recoded bacteria would be improperly translated if it contained the repurposed codons due to the modified protein expression machinery the GRO possesses. Such resistance was demonstrated by Lajoie in an experiment in which he infected E. coli modified to have no UAG codons with two types of viruses: a T7 virus that contained UAG codons in critical genes, and a T4 virus that did not. As expected, the modified cells showed resistance to T7, but were infected normally by T4. The researchers concluded that more extensive genetic code modifications would probably make the bacteria immune to viral infection entirely.2 Using such organisms in lieu of unmodified ones in bacteria-dependent processes like cheese- and yogurt-making, biogas manufacturing, and hormone production would reduce the cost of those processes by eliminating the hassle and expense associated with viral infection.3,4 It should be noted that while GROs would theoretically be resistant to infection, they would also be unable to “infect” anything themselves. If GRO genes were to be taken up by other organisms, they would also be improperly translated as well, making horizontal gene transfer impossible. This means that GROs are “safe” in the sense that they would not be able to spread their genes to organisms in the wild like other GMOs can.5

GROs could also be used to make novel proteins. The eliminated codons could be repurposed to code for amino acids not found in nature, or non-standard amino acids (NSAAs). It is possible to use GRO’s to produce a range of proteins with expanded chemical properties, free from the limits imposed by strictly using the 20 standard amino acids.2,3 These proteins could then be used in medical or industrial applications. For example, the biopharmaceutical company Ambrx develops proteins with NSAAs for use as medicine to treat cancer and other diseases.6

While GRO’s can do incredible things, they are not without their drawbacks. Proteins produced by the modified cells could turn out to be toxic, and if these GROs manage to escape from the lab into the wild, they could flourish due to their resistance to viral infection.2,3 To prevent this scenario from happening, Ostrov’s team has devised a failsafe. In previous experiments, the researchers modified bacteria so that two essential genes, named adk and tyrS, depended on NSAAs to function. Because NSAAs aren’t found in the wild, this modification effectively confines the bacteria within the lab, and it is difficult for the organisms to thwart this containment strategy spontaneously. Ostrov et al. intend to implement this failsafe in their 57-codon E. coli.2

Genetic recoding is an exciting development in synthetic biology, one that offers a new paradigm for genetic modification. Though the field is still young and the sheer amount of DNA changes needed to recode organisms poses significant challenges to the creation of GROs, genetic recoding has the potential to yield tremendously useful organisms.

References

  1. Lajoie, M. J., et al. Science 2013, 342, 357-360.
  2. Ostrov, N., et al. Science 2016, 353, 819-822.
  3. Bohannon, J. Biologists are close to reinventing the genetic code of life. Science, Aug. 18, 2016. http://www.sciencemag.org/news/2016/08/biologists-are-close-reinventing-genetic-code-life (accessed Sept. 29, 2016).
  4. Diep, F. What are genetically recoded organisms?. Popular Science, Oct. 15, 2013. http://www.popsci.com/article/science/what-are-genetically-recoded-organisms (accessed Sept. 29, 2016)
  5. Commercial and industrial applications of microorganisms. http://www.contentextra.com/lifesciences/files/topicguides/9781447935674_LS_TG2_2.pdf (accessed Nov. 1 2016)
  6. Ambrx. http://ambrx.com/about/ (accessed Oct. 6, 2016)

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CRISPR: The Double-Edged Sword of Genetic Engineering

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CRISPR: The Double-Edged Sword of Genetic Engineering

The phrase “genetic engineering” often brings to mind a mad scientist manipulating mutant genes or a Frankenstein-like creation emerging from a test tube. Brought to the forefront by heated debates over genetically modified crops, genetic engineering has long been viewed as a difficult, risky process fraught with errors.1

The intentional use of CRISPRs, short for clustered regularly interspaced sport palindromic repeats, turned the world of genetic engineering on its head. Pioneered by Jennifer Doudna of Berkeley2 in 2012 and praised as the “Model T” of genetic engineering,3 CRISPR as a tool is both transforming what it means to edit genes and raising difficult ethical and moral questions about genetic engineering as a discipline.

CRISPR itself is no new discovery. The repeats are sequences used by bacteria and microorganisms to protect against viral infections. Upon invasion by a virus, CRISPR identifies the DNA segments from the invading virus, processes them into “spacers,” or short palindromic repeats of DNA, and inserts them back into the bacterial genome.4 When the bacterial DNA undergoes transcription, the resulting RNA is a single-chain molecule that acts as a guide to destroy viral material. In a way, the RNA functions as a blacklist for the bacterial cell: re-invasion attempts by the same virus are quickly identified using the DNA record and subsequently stopped. That same blacklist enables CRISPR to be a powerful engineering tool. The spacers act as easily identifiable flags in the genome, allowing for high precision when manipulating individual nucleotide sequences in genes.5 The old biotechnology system can be perceived as a confused traveler holding an inaccurate map, with a general location and vague person to meet. By the same analogy, CRISPR provides a mugshot of the person to meet and the precise coordinates of where to find them. Scientists have taken advantage of this precision and now use modified proteins, such as Cas-9, to activate gene expression as opposed to cutting the DNA,6 an innovative style of genetic engineering. Traditional genetic engineering can be a shot in the dark, but with the accuracy of CRISPR, mutations are very rare.7 For the first time, scientists are able to pinpoint the exact location of genes, cut the desired sequence, and leave no damage. Another benefit of CRISPR is the reincorporation of genes that have become lost, either by breeding or evolution, bringing back extinct qualities. For example, scientists have succeeded in introducing mammoth genes into living elephant cells.8,9 Even better, CRISPR is very inexpensive, costing around $75 to edit a gene at Baylor College of Medicine,10 and accessible to anyone with biological expertise, starting with graduate students.11 The term “Model T of genetic engineering” could hardly be more appropriate.

CRISPR stretches the boundaries of bioengineering. One enterprising team from China led by oncologist Dr. Lu You has already begun trials on humans. They plan on injecting cells modified using the CRISPR-Cas9 system into patients with metastatic non-small cell lung cancer--patients who otherwise have little hope of survival.12 To prevent attacks on healthy cells, extracted critical immune mediators called T cells will be edited with the CRISPR-Cas9 system. CRISPR will identify and “snip” out a gene that encodes PD-1, a protein that acts as a check on the T-cell’s capacity to launch an immune response. Essentially, Lu’s team is creating super-T-cells, ones that have no mercy for any suspicious activity. This operation is very risky. CRISPR’s mechanisms are not thoroughly understood, and mistakes with gene editing could have drastic consequences.11 In addition, the super T cells could attack in an autoimmune reaction, leading to degradation of critical organs. In an attempt to prevent such a response, Lu’s team will extract T-cells from the tumor itself, as those T-cells would likely have already specialized in attacking cancer cells. To ensure patient safety, the team will examine the effects of three different dosage regimens on ten patients, watching closely for side effects and responsiveness.

Trials involving such cutting-edge technology raise many questions. With ease of use and accessibility, CRISPR has the potential to become a tool worthy of science fiction horror. Several ethics groups have raised concerns over the inappropriate use of CRISPR: they worry that the technology could be used by amateurs and thus yield dangerous results. In spite of these concerns, China greenlit direct editing of human embryos, creating international uproar and a moratorium on further human embryo testing.13 But such editing could lead to new breakthroughs: CRISPR could reveal how genes regulate early embryonic development, leading to a better understanding of infertility and miscarriages.14

This double-edged nature defines CRISPR-Cas9’s increasing relevance at the helm of bioengineering. The momentum behind CRISPR and its seemingly endless applications continue to broach long-unanswered questions in biology, disease treatment, and genetic engineering. Still, with that momentum comes caution: with CRISPR’s discoveries come increasingly blurred ethical distinctions.

References

  1. Union of Concerned Scientists. http://www.ucsusa.org/food_and_agriculture/our-failing-food-system/genetic-engineering/risks-of-genetic-engineering.html#.WBvf3DKZPox (accessed Sept. 30, 2016).
  2. Doudna, J. Nature [Online] 2015, 7583, 469-471. http://www.nature.com/news/genome-editing-revolution-my-whirlwind-year-with-crispr-1.19063 (accessed Oct. 5, 2016).
  3. Mariscal, C.; Petropanagos, A. Monash Bioeth. Rev. [Online] 2016, 102, 1-16. http://link.springer.com/article/10.1007%2Fs40592-016-0062-2 (accessed Oct. 5, 2016).
  4. Broad Institute. https://www.broadinstitute.org/what-broad/areas-focus/project-spotlight/questions-and-answers-about-crispr (accessed Sept. 30, 2016).
  5. Pak, E. CRISPR: A game-changing genetic engineering technique. Harvard Medical School, July 31, 2015. http://sitn.hms.harvard.edu/flash/2014/crispr-a-game-changing-genetic-engineering-technique/ (accessed Sept. 30, 2016)
  6. Hendel, A. et al. Nature Biotech. 2015, 33, 985-989.
  7. Kleinstiver, B. et al. Nature. 2016, 529, 490-495.
  8. Shapiro, B. Genome Biology. [Online] 2015, 228. N.p. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4632474/ (accessed Nov. 1, 2016).
  9. Reardon, S. Nature. [Online] 2016, 7593, 160-163. http://www.nature.com/news/welcome-to-the-crispr-zoo-1.19537 (accessed Nov. 1, 2016).
  10. Baylor College of Medicine. https://www.bcm.edu/research/advanced-technology-core-labs/lab-listing/mouse-embryonic-stem-cell-core/services/crispr-service-schedule (accessed Sept. 30, 2016).
  11. Ledford, H. Nature. [Online] 2015, 7554, 20-24. http://www.nature.com/news/crispr-the-disruptor-1.17673 (accessed Oct. 11, 2016).
  12. Cyranoski, D. Nature. [Online] 2016, 7613, 476-477. http://www.nature.com/news/chinese-scientists-to-pioneer-first-human-crispr-trial-1.20302 (accessed Sept. 30, 2016).
  13. Kolata, G. Chinese Scientists Edit Genes of Human Embryos, Raising Concerns. The New York Times, April 23, 2015. http://www.nytimes.com/2015/04/24/health/chinese-scientists-edit-genes-of-human-embryos-raising-concerns.html?_r=0 (accessed Oct. 2, 2016).
  14. Stein, R. Breaking Taboo, Swedish Scientist Seeks To Edit DNA of Healthy Human Embryos. NPR, Sept. 22, 2016. http://www.npr.org/sections/health-shots/2016/09/22/494591738/breaking-taboo-swedish-scientist-seeks-to-edit-dna-of-healthy-human-embryos (accessed Sept. 22, 2016).

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Telomeres: Ways to Prolong Life

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Telomeres: Ways to Prolong Life

Two hundred years ago, the average life expectancy oscillated between 30 and 40 years, as it had for centuries before. Medical knowledge was fairly limited to superstition and folk cures, and the science behind what actually caused disease and death was lacking. Since then, the average lifespan of human beings has skyrocketed due to scientific advancements in health care, such as an understanding of bacteria and infections. Today, new discoveries are being made in cellular biology which, in theory, could lead us to the next revolutionary leap in life span. Most promising among these recent discoveries is the manipulation of telomeres in order to slow the aging process, and the use of telomerase to identify cancerous cells.

Before understanding how telomeres can be utilized to increase the average lifespan of humans, it is essential to understand what a telomere is. When cells divide, their DNA must be copied so that all of the cells share an identical DNA sequence. However, the DNA cannot be copied all the way to the end of the strand, resulting in the loss of some DNA at the end of the sequence with every single replication.1 To prevent valuable genetic code from being cut off during cell division, our DNA contains telomeres, a meaningless combination of nucleotides at the end of our chromosomal sequences that can be cut off without consequences to the meaningful part of the DNA. Repeated cell replication causes these protective telomeres to become shorter and shorter, until valuable genetic code is eventually cut off, causing the cell to malfunction and ultimately die.1 The enzyme telomerase functions in cells to rebuild these constantly degrading telomeres, but its activity is relatively low in normal cells as compared to cancer cells.2

The applications of telomerase manipulation have only come up fairly recently, with the discovery of the functionality of both telomeres and telomerase in the mid 80’s by Nobel Prize winners Elizabeth Blackburn, Carol Grieder, and Jack Sjozak.3 Blackburn discovered a sequence at the end of chromosomes that was repeated several times, but could not determine what the purpose of this sequence was. At the same time, Sjozak was observing the degradation of minichromosomes, chromatin-like structures which replicated during cell division when introduced to a yeast cell. Together, they combined their work by isolating Blackburn’s repeating DNA sequences, attaching them to Sjozak’s minichromosomes, and then placing the minichromosomes back inside yeast cells. With the new addition to their DNA sequence, the minichromosomes did not degrade as they had before, thus proving that the purpose of the repeating DNA sequence, dubbed the telomere, was to protect the chromosome and delay cellular aging.

Because of the relationship between telomeres and cellular aging, many scientists theorize that cell longevity could be enhanced by finding a way to control telomere degradation and keep protective caps on the end of cell DNA indefinitely.1 Were this to be accomplished, the cells would be able to divide an infinite number of times before they started to lose valuable genetic code, which would theoretically extend the life of the organism as a whole.

In addition, studies into telomeres have revealed new ways of combatting cancer. Although there are many subtypes of cancer, all variations of cancer involve the uncontrollable, rapid division of cells. Despite this rapid division, the telomeres of cancer cells do not shorten like those of a normal cell upon division, otherwise this rapid division would be impossible. Cancer cells are likely able to maintain their telomeres due to their higher levels of telomerase.3 This knowledge allows scientists to use telomerase levels as an indicator of cancerous cells, and then proceed to target these cells. Vaccines that target telomerase production have the potential to be the newest weapon in combatting cancer.2 Cancerous cells continue to proliferate at an uncontrollable rate even when telomerase production is interrupted. However, without the telomerase to protect their telomeres from degradation, these cells eventually die.

As the scientific community advances its ability to control telomeres, it comes closer to controlling the process of cellular reproduction, one of the many factors associated with human aging and cancerous cells. With knowledge in these areas continuing to develop, the possibility of completely eradicating cancer and slowing the aging process is becoming more and more realistic.

References

  1. Genetic Science Learning Center. Learn.Genetics. http://learn.genetics.utah.edu (accessed Oct. 5, 2016).
  2. Shay, J. W.; Woodring W. E.  NRD. [Online] 2016, 5. http://www.nature.com/nrd/journal/v5/n7/full/nrd2081.html (accessed Oct. 16, 2016).
  3. The 2009 Nobel Prize in Physiology or Medicine - Press Release. The Nobel Prize. https://www.nobelprize.org/nobel_prizes/medicine/laureates/2009/press.html (accessed Oct. 4, 2016).

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Astrocytes: Shining the Spotlight on the Brain’s Rising Star

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Astrocytes: Shining the Spotlight on the Brain’s Rising Star

We have within us the most complex and inspiring stage to ever be set: the human brain. The cellular components of the brain act as players, interacting through chemical and electrical signaling to elicit emotions and convey information. Although most of our attention has in the past been focused on neurons, which were erroneously presumed to act alone in their leading role, scientists are slowly realizing that astrocytes—glial cells in the brain that were previously assumed to only have a supportive role in association with neurons—are so much more than merely supporting characters.

Though neurons are the stars, most of the brain is actually composed of supportive cells like microglia, oligodendrocytes, and, most notably, astrocytes. Astrocytes, whose formal name is a misnomer given that modern imaging technology reveals they actually maintain a branch-like shape rather than a star-like one, exist as one of three mature types in the grey matter, white matter, or retina. Structurally, the grey matter astrocyte variant exhibits bushy, root-like tendrils and a spherical shape. The white matter variant, commonly found in the hippocampus, favors finer extensions called processes. The retinal variant features an elongated structure.¹

Functionally, astrocytes were previously believed to play a solely supportive role, as they constitute a large percentage of the glial cells present in the brain. Glial cells are essentially all of the non-neural cells in the brain that assist in basic functioning; they themselves are not electrically excitable. However, current research suggests that astrocytes play far more than merely a supporting role in the brain. Astrocytes and neurons directly interact to interpret stimuli and store memories⁴, among many other yet undiscovered tasks.

Although astrocytes are not electrically excitable, astrocytes communicate with neurons via calcium signaling and the neurotransmitter glutamate.² Calcium signaling works whereby intracellular calcium in astrocytes is released upon excitation and is propagated in waves that move through neighboring astrocytes and neurons. Neurons experience a responsive increase in intracellular calcium if they are directly touching affected astrocytes, as the signal is communicated via gap junctions rather than synaptically. Such signalling is unidirectional; calcium excitation can move from astrocyte to neuron, but not from neuron to astrocyte.³ The orientation of astrocytes in different regions of the brain and their proximity to neurons allows them to form close communication networks that help information travel throughout the central nervous system.

Astrocytes in the hippocampus play a role in memory development. They act as an intermediary cell in a neural inhibitory circuit that utilizes acetylcholine, glutamate, and Gamma-Aminobutyric Acid (GABA) to solidify experiential learning and memory formation. Disruption of cholinergic signaling, signaling relating to acetylcholine, prohibits the formation of memories in the dentate gyrus of the hippocampal formation. Astrocytes act as mediators that convert cholinergic inputs into glutamatergic activation of neurons.⁴ Without the assistance of astrocytic networks in close association with neurons, memory formation and long-term potentiation would be far less efficient if even still possible.

Astrocytes’ ability to interpret and release chemical neurotransmitters, especially glutamate, allows them to regulate the intensity of synaptic firing in neurons.⁵ Increased glutamate uptake by astrocytes reduces synaptic strength in associated neurons by decreasing neuronal concentration of glutamate.⁶ Regulation of synaptic strength in firing is crucial for healthy brain function. If synapses fire too much or too powerfully, they may overwhelm the brain. Conversely, if synapses fire too infrequently or not strongly enough, messages might not make their way throughout the central nervous system. The ability of astrocytes to modulate synaptic activity through selective glutamate interactions puts them in an integral position to assist in consistent and efficient transmission of information throughout the human body.

Through regulation of neurotransmitters and psychoactive chemicals in the brain, astrocytes are able to maintain homeostasis in the central nervous system. Potassium buffering and balancing of pH are the major ways that astrocytes assist in maintaining optimal conditions for brain function.⁷ Astrocytes are able to compensate for the slow re-uptake of potassium by neurons, thus decluttering the extracellular space of free potassium in response to neuronal activity. Re-uptake of these ions is extremely important to brain function as synaptic transmission by neurons relies on electrically switching membrane potentials along neuronal axons.

Due to their role in synaptic regulation and their critical position in the brain network, astrocytes also have the potential to aid in therapies for dealing with neurological disorders. For example, epileptic seizures have been found to be related to an excitatory loop between neurons and astrocytes. Focal ictal discharges, the brain activity responsible for epileptic seizures, are correlated to hyperactivity in neurons as well as an increase in intracellular calcium in nearby astrocytes; the calcium oscillations then spread to neighboring astrocyte networks to perpetuate the ictal discharge and continue the seizure. Astrocytes in epileptic brain tissues exhibit structural changes that may favor such a positive feedback loop. Inhibition of calcium uptake in astrocytes, and consequent decrease in release of glutamate and ATP, is linked to suppression of ictal discharges, and therefore linked to a decrease in the severity and occurrence of epileptic seizures.⁸ Furthermore, it is evident that astrocyte activity also plays a role in memory loss associated with Alzheimer’s Disease. Although astrocytes in the hippocampus contain low levels of the neurotransmitter GABA under normal conditions, hyperactive astrocytes near amyloid plaques in affected individuals exhibit increased levels of GABA that are not evident in other types of glial cells. GABA is the main inhibitory neurotransmitter in the brain, and abnormal increases in GABA are associated with Alzheimer’s Disease; introducing antagonist molecules has been shown to reduce memory impairment, but at the cost of inducing seizures.⁹ Since there is a shift in GABA release by astrocytes between normal and diseased individuals, astrocytes could be as the key to remedying neurodegenerative conditions like Alzheimer’s.

In addition to aiding in treatment of neurological disorders, astrocytes may also help stroke victims. Astrocytes ultimately support damaged neurons by donating their mitochondria to the neurons.¹⁰ Mitochondria produce adenosine triphosphate (ATP) and act as the energy powerhouse in eukaryotic cells; active cells like neurons cannot survive without them. Usually neurons accommodate their exceptionally large energy needs by multiplying their intracellular mitochondria via fission. However, when neurons undergo stress or damage, as in the case of stroke, the neuron is left without its source of energy. New research suggests that astrocytes come to the rescue by releasing their own mitochondria into the extracellular environment in response to high levels of the enzyme CD38, so that damaged neurons can absorb the free mitochondria and survive the damage.¹¹ Astrocytes also help restore neuronal mitochondria and ATP production post-insult by utilizing lactate shuttles, in which astrocytes generate lactate through anaerobic respiration and then pass the lactate to neurons where it can be used as a substrate for oxidative metabolism¹². Such a partnership between astrocytes and neurons presents researchers with the option of using astrocyte-targeted therapies to salvage neuronal systems in stroke victims and others afflicted by ailments associated with mitochondrial deficiencies in the brain.

Essentially, astrocytes are far more than the background supporters they were once thought to be. Before modern technological developments, the capabilities and potential of astrocytes were left woefully unnoticed. Astrocytes interact both directly and indirectly with neurons through chemical signaling to create memories, interpret stimuli, regulate signaling, and, maintain a healthy central nervous system. A greater understanding of the critical role astrocytes play in the human brain could allow scientists to develop astrocyte-targeted therapeutic practices. As astrocytes slowly inch their way into the spotlight of neuroscientific research, there is so much yet to be discovered.

References

  1. Kimelberg, H.K.; Nedergaard, M. Neurotherapeutics 2010, 7, 338-353
  2. Schummers, J. et al. Science 2008, 320, 1638-1643
  3. Nedergaard, M. Science 1994, 263, 1768+
  4. Ferrarelli, L. K. Sci. Signal 2016, 9, ec126
  5. Gittis, A. H.; Brasier, D. J. Science 2015, 349, 690-691
  6. Pannasch, U. et al. Nature Neuroscience 2014, 17, 549+
  7. Kimelberg, H.K.; Nedergaard, M. Neurotherapeutics 2010, 7(4), 338-353
  8. Gomez-Gonzalo, M. et al. PLoS Biology 2010, 8,
  9. Jo, S. et al. Nature Medicine 2014, 20, 886+
  10. VanHook, A. M. Sci. Signal 2016, 9, ec174
  11. Hayakawa, K. et al. Nature 2016, 535, 551-555
  12. Genc, S. et al. BMC Systems Biology 2011, 5, 162

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Surviving Without the Sixth Sense

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Surviving Without the Sixth Sense

Though references to the “sixth sense” often bring images of paranormal phenomena to mind, the scientific world has bestowed this title to our innate awareness of our own bodies in space. Proprioception, the official name of this sense, is what allows us to play sports and navigate in the dark. Like our other five senses, our capability for spatial awareness has become so automatic that we hardly ever think about it. But scientists at the National Institute of Health (NIH) have made some breakthroughs about a genetic disorder that causes people to lack this sense, leading to skeletal abnormalities, balance difficulties, and even the inability to discern some forms of touch.1

The gene PIEZO2 has been associated with the body’s ability to sense touch and coordinate physical actions and movement. While there is not a substantial amount of research about this gene, previous studies on mice show that it is instrumental in proprioception.2 Furthermore, NIH researchers have recently attributed a specific phenotype to a mutation in PIEZO2, opening a potential avenue to unlock its secrets.

Pediatric neurologist Carsten G. Bönnermann, the senior investigator at the NIH National Institute of Neurological Disorders and Stroke, had been studying two patients with remarkably similar cases when he met Alexander Chesler at a lecture. Chesler, an investigator at the NIH National Center for Complementary and Integrative Health, joined Bönnermann in performing a series of genetic and practical tests to investigate the disorder.1

The subjects examined were an 8-year-old girl and an 18-year-old woman from different backgrounds and geographical areas. Even though these patients were not related, they both exhibited a set of similar and highly uncommon phenotypes. For example, each presented with scoliosis - unusual sideways spinal curvature - accompanied by fingers, feet, and hips that could bend at atypical angles. In addition to these physical symptoms, the patients experienced difficulty walking, substantial lack of coordination, and unusual responses to physical touch.1These symptoms are the result of PIEZO2 mutations that block the gene’s normal activity or production. Using full genome sequencing, researchers found that both patients have at least one recessively-inherited nonsense variant in the coding region of PIEZO2.1 But because these patients represent the first well-documented cases of specific proprioceptive disorders, there is not an abundance of research about the gene itself. Available previous studies convey that PIEZO2 encodes a mechanosensitive protein - that is, it generates electrical nerve signals in response to detected changes in factors such as cell shape.2 This function is responsible for many of our physical capabilities, including spatial awareness, balance, hearing, and touch. In fact, PIEZO2 has even been found to be expressed in neurons that control mechanosensory responses, such as perception of light touch, in mice. Past studies found that removing the gene in mouse models caused intolerable limb defects.2 Since this gene is highly homogenous in humans and in mice (the two versions are 95% similar), many researchers assumed that humans could not live without the gene either. According to Bönnermann and Chesler, however, it is clear that this PIEZO2 mutation does not cause a similar fate in humans.

Along with laboratory work, Bönnermann and Chesler employed techniques to further investigate the tangible effects of the mutations. Utilizing a control group for comparison, the researchers presented patients with a set of tests that examined their movement and sensory abilities. The results were startling, to say the least. The patients revealed almost a total lack of proprioception when blindfolded. They stumbled and fell while walking and could not determine which way their joints were moving without looking. In addition, both failed to successfully move a finger from their noses to a target. The absence of certain sensory abilities is also astonishing - both patients could not feel the vibrations of a tuning fork pressed against their skin, could not differentiate between ends of a caliper pressed against their palms, and could not sense a soft brush across their palms and bottom of their feet. Furthermore, when this same soft brush was swept across hairy skin, both of the patients claimed that the sensation was prickly. This particular result revealed that the subjects were generally missing brain activation in the region linked to physical sensation, yet they appeared to have an emotional response to the brushing across hairy skin; these specific brain patterns directly contrasted with those of the control group participants. Additional tests performed on the two women revealed that the patients’ detection of pain, itching, and temperature was normal when compared to the control group findings, and that they possessed nervous system capabilities and cognitive functions appropriate for their ages.1

Because the patients are still able to function in daily life, it is apparent that the nervous system has alternate pathways that allow them to use sight to largely compensate for their lack of proprioception.3,4 Through further research, scientists can tap into these alternate pathways when designing therapies for similar patients. Additionally, the common physical features of both patients shed light on the fact that PIEZO2 gene mutations could contribute to the observed genetic musculoskeletal disorders.3 This suggests that proprioception itself is necessary for normal musculoskeletal development; it is possible that abnormalities developed over time as a result of patients’ postural responses and compensations to their deficiencies.4

In an era when our lives depend so heavily on our abilities to maneuver our bodies and coordinate movements, the idea of lacking proprioception is especially concerning. Bönnermann and Chesler’s discoveries open new doors for further investigation of PIEZO2’s role in the nervous system and musculoskeletal development. These discoveries can also aid in better understanding a variety of other neurological disorders. But, there is still much unknown about the full effects of the PIEZO2 mutation. For example, we do not know if musculoskeletal abnormalities injure the spinal cord, if the gene mutation poses additional consequences for the elderly, or if women are more susceptible to the disorder than are men. Furthermore, it is very likely that there are numerous other patients around the world who present similar symptoms to the 8-year-old girl and 18-year-old woman observed by Bönnermann and Chesler. While researchers work towards gaining a better understanding of the disease and developing specific therapies, these patients must focus on other coping mechanisms, such as reliance on vision, to accomplish even the most basic daily activities. Because contrary to popular perception, the sixth sense is not an ability to see ghosts; it is so much more.

References

  1. Chesler, A. T. et al. N Engl J Med. 2016, 375, 1355-1364
  2. Woo, S. et al. Nat Neurosci. 2015, 18, 1756-1762
  3. “‘Sixth sense’ may be more than just a feeling”. National Institutes of Health, https://www.nih.gov/news-events/news-releases/Sixth-sense-may-be-more-just-feeling (accessed Sept. 22, 2016).
  4. Price, Michael. “Researchers discover gene behind ‘sixth sense’ in humans”. Science Magazine, http://www.sciencemag.org/news/2016/09/researchers-discover-gene-behind-sixth-sense-humans (accessed Sept. 22, 2016)

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The Creation of Successful Scaffolds for Tissue Engineering

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The Creation of Successful Scaffolds for Tissue Engineering

Abstract

Tissue engineering is a broad field with applications ranging from pharmaceutical testing to total organ replacement. Recently, there has been extensive research on creating tissue that is able to replace or repair natural human tissue. Much of this research focuses on the creation of scaffolds that can both support cell growth and successfully integrate with the surrounding tissue. This article will introduce the concept of a scaffold for tissue engineering; discuss key areas of research including biomolecule use, vascularization, mechanical strength, and tissue attachment; and introduce some important recent advancements in these areas.

Introduction

Tissue engineering relies on four main factors: the growth of appropriate cells, the introduction of the proper biomolecules to these cells, the attachment of the cells to an appropriate scaffold, and the application of specific mechanical and biological forces to develop the completed tissue.1

Successful cell culture has been possible since the 1960’s, but these early methods lacked the adaptability necessary to make functioning tissues. With the introduction of induced pluripotent stem cells in 2008, however, researchers have not faced the same resource limitation previously encountered. As a result, the growth of cells of a desired type has not been limiting to researchers in tissue engineering and thus warrants less concern than other factors in contemporary tissue engineering.2,3

Similarly, the introduction of essential biomolecules (such as growth factors) to the developing tissue has generally not restricted modern tissue engineering efforts. Extensive research and knowledge of biomolecule function as well as relatively reliable methods of obtaining important biomolecules have allowed researchers to make engineered tissues more successfully emulate functional human tissue using biomolecules.4,5 Despite these advancements in information and procurement methods, however, the ability of biomolecules to improve engineered tissue often relies on the structure and chemical composition of the scaffold material.6

Cellular attachment has also been a heavily explored field of research. This refers specifically to the ability of the engineered tissue to seamlessly integrate into the surrounding tissue. Studies in cellular attachment often focus on qualities of scaffolds such as porosity as well as the introduction of biomolecules to encourage tissue union on the cellular level. Like biomolecule effectiveness, successful cellular attachment depends on the material and structure of the tissue scaffolding.7

Also critical to developing functional tissue is exposing it to the right environment. This development of tissue properties via the application of mechanical and biological forces depends strongly on finding materials that can withstand the required forces while supplying cells with the necessary environment and nutrients. Previous research in this has focused on several scaffold materials for various reasons. However, improvements to the material or the specific methods of development are still greatly needed in order to create functional implantable tissue. Because of the difficulty of conducting research in this area, devoted efforts to improving these methods remain critical to successful tissue engineering.

In order for a scaffold to be capable of supporting cells until the formation of a functioning tissue, it is necessary to satisfy several key requirements, principally introduction of helpful biomolecules, vascularization, mechanical function, appropriate chemical and physical environment, and compatibility with surrounding biological tissue.8,9 Great progress has been made towards satisfying many of these conditions, but further research in the field of tissue engineering must address challenges with existing scaffolds and improve their utility for replacing or repairing human tissue.

Key Research Areas of Scaffolding Design

Biomolecules

Throughout most early tissue engineering projects, researchers focused on simple cell culture surrounding specific material scaffolds.10 Promising developments such as the creation of engineered cartilage motivated further funding and interest in research. However, these early efforts missed out on several crucial factors to tissue engineering that allow implantable tissue to take on more complex functional roles. In order to create tissue that is functional and able to direct biological processes alongside nearby natural tissue, it is important to understand the interactions of biomolecules with engineered tissue.

Because the ultimate goal of tissue engineering is to create functional, implantable tissue that mimics biological systems, most important biomolecules have been explored by researchers in the medical field outside of tissue engineering. As a result, a solid body of research exists describing the functions and interactions of various biomolecules. Because of this existing information, understanding their potential uses in tissue engineering relies mainly on studying the interactions of biomolecules with materials which are not native to the body; most commonly, these non-biological materials are used as scaffolding. To complicate the topic further, biomolecules are a considerably large category encompassing everything from DNA to glucose to proteins. As such, it is most necessary to focus on those that interact closely with engineered tissue.

One type of biomolecule that is subject to much research and speculation in current tissue engineering is the growth factor.11 Specific growth factors can have a variety of functions from general cell proliferation to the formation of blood cells and vessels.12-14 They can also be responsible for disease, especially the unchecked cell generation of cancer.15 Many of the positive roles have direct applications to tissue engineering. For example, Transforming Growth Factor-beta (TGF-β) regulates normal growth and development in humans.16 One study found that while addition of ligands to engineered tissue could increase cellular adhesion to nearby cells, the addition also decreased the generation of the extracellular matrix, a key structure in functional tissue.17 To remedy this, the researchers then tested the same method with the addition of TGF-β. They saw a significant increase in the generation of the extracellular matrix, improving their engineered tissue’s ability to become functional faster and more effectively. Clearly, a combination of growth factors and other tissue engineering methods can lead to better outcomes for functional tissue engineering.

With the utility of growth factors established, delivery methods become very important. Several methods have been shown as effective, including delivery in a gelatin carrier.18 However, some of the most promising procedures rely on the scaffolding’s properties. One set of studies mimicked the natural release of growth factors through the extracellular matrix by creating a nanofiber scaffold containing growth factors for delayed release.19 The study saw an positive influence on the behavior of cells as a result of the release of growth factor. Other methods vary physical properties of the scaffold such as pore size to trigger immune pathways that release regenerative growth factors, as will be discussed later. The use of biomolecules and specifically growth factors is heavily linked to the choice of scaffolding material and can be critical to the success of an engineered tissue.

Vascularization

Because almost all tissue cannot survive without proper oxygenation, engineered tissue vascularization has been a focus of many researchers in recent years to optimize chances of engineered tissue success.20 For many of the areas of advancement, this process depends on the scaffold.21 The actual requirements for level and complexity of vasculature vary greatly based on the type of tissue; the requirements for blood flow in the highly vascularized lungs are different than those for cortical bone.22,23 Therefore, it is more appropriate for this topic to address the methods which have been developed for creating vascularized tissue rather than the actual designs of specific tissues.

One method that has shown great promise is the use of modified 3D printers to cast vascularized tissue.24 This method uses the relatively new printing technology to create carbohydrate glass networks in the form of the desired vascular network. The network is then coated with a hydrogel scaffold to allow cells to grow. The carbohydrate glass is then dissolved from inside of the hydrogel, leaving an open vasculature in a specific shape. This method has been successful in achieving cell growth in areas of engineered tissue that would normally undergo necrosis. Even more remarkably, the created vasculature showed the ability to branch into a more complex system when coated with endothelial cells.24

However, this method is not always applicable. Many tissue types require scaffolds that are more rigid or have different properties than hydrogels. In this case, researchers have focused on the effect of a material’s porosity on angiogenesis.7,25 Several key factors have been identified for blood vessel growth, including pore size, surface area, and endothelial cell seeding similar to that which was successful in 3D printed hydrogels. Of course, many other methods are currently being researched based on a variety of scaffolds. Improvements on these methods, combined with better research into the interactions of vascularization with biomaterial attachment, show great promise for engineering complex, differentiated tissue.

Mechanical Strength

Research has consistently demonstrated that large-scale cell culture is not limiting to bioengineering. With the introduction of technology like bioreactors or three-dimensional cell culture plates, growing cells of the desired qualities and in the appropriate form continues to become easier for researchers; this in turn allows for a focus on factors beyond simply gathering the proper types of cells.2 This is important because most applications in tissue engineering require more than just the ability to create groupings of cells—the cells must have a certain degree of mechanical strength in order to functionally replace tissue that experiences physical pressure.

The mechanical strength of a tissue is a result of many developmental factors and can be classified in different ways, often based on the type of force applied to the tissue or the amount of force the tissue is able to withstand. Regardless, mechanical strength of a tissue primarily relies on the physical strength of the tissue and its ability for its cells to function under an applied pressure; these are both products of the material and fabrication methods of the scaffolding used. For example, scaffolds in bone tissue engineering are often measured for compressive strength. Studies have found that certain techniques, such as cooking in a vacuum oven, may increase compressive strength.26 One group found that they were able to match the higher end of the possible strength of cancellous (spongy) bone via 3D printing by using specific molecules within the binding layers.27 This simple change resulted in scaffolding that displayed ten times the mechanical strength of scaffolding with traditional materials, a value within the range for natural bone. Additionally, the use of specific binding agents between layers of scaffold resulted in increased cellular attachment, the implications of which will be discussed later.27 These changes result in tissue that is more able to meet the functional requirements and therefore to be easily used as a replacement for bone. Thus, simple changes in materials and methods used can drastically increase the mechanical usability of scaffolds and often have positive effects on other important qualities for certain types of tissue.

Clearly, not all designed tissues require the mechanical strength of bone; contrastingly for contrast, the brain experiences less than one kPa of pressure compared to the for bone’s 106 kPa pressure bones experience.28 Thus, not all scaffolds must support the same amount of pressure, and scaffolds must be made accordingly to accommodate for these structural differences. Additionally, other tissues might experience forces such as tension or torsion based on their locations within the body. This means that mechanical properties must be looked at on a tissue-by-tissue basis in order to determine their corresponding scaffolding structures. But mechanical limitations are only a primary factor in bone, cartilage, and cardiovascular engineered tissue, the latter of which has significantly more complicated mechanical requirements.29

Research in the past few years has investigated increasingly complex aspects of scaffold design and their effects on macroscopic physical properties. For example, it is generally accepted that pore size and related surface area within engineered bone replacements are key to cellular attachment. However, recent advances in scaffold fabrication techniques have allowed researchers to investigate very specific properties of these pores such as their individual geometry. In one recent study, it was found that using an inverse opal geometry--an architecture known for its high strength in materials engineering--for pores led to a doubling of mineralization within a bone engineering scaffold.30 Mineralization is a crucial quality of bone because of its contribution to compressive strength.31 This result is so important because it demonstrates the recent ability of researchers to alter scaffolds on a microscopic level in order to affect macroscopic changes in tissue properties.

Attachment to Nearby Tissue

Even with an ideal design, a tissue’s success as an implant relies on its ability to integrate with the surrounding tissue. For some types of tissue, this is simply a matter of avoiding rejection by the host through an immune response.32 In these cases, it is important to choose materials with a specific consideration for reducing this immune response. Over the past several decades, it has been shown that the key requirement for biocompatibility is the use of materials that are nearly biologically inert and thus do not trigger a negative response from natural tissue.33 This is based on the strategy which focuses on minimizing the immune response of tissue surrounding the implant in order to avoid issues such as inflammation which might be detrimental to the patient undergoing the procedure. This method has been relatively effective for implants ranging from total joint replacements to heart valves.

Avoiding a negative immune response has proven successful for some medical fields. However, more complex solutions involving a guided immune response might be necessary for engineered tissue implants to survive and take on the intended function. This issue of balancing biochemical inertness and tissue survival has led researchers to investigate the possibility of using the host immune response in an advantageous way for the success of the implant.34 This method of intentionally triggering surrounding natural tissue relies on the understanding that immune response is actually essential to tissue repair. While an inert biomaterial may be able to avoid a negative reaction, it will also discourage a positive reaction. Without provoking some sort of response to the new tissue, an implant will remain foreign to bordering tissue; this means that the cells cannot take on important functions, limiting the success of any biomaterial that has more than a mechanical use.

Current studies have focused primarily on modifying surface topography and chemistry to target a positive immune reaction in the cells surrounding the new tissue. One example is the grafting of oligopeptides onto the surface of an implant to stimulate macrophage response. This method ultimately leads to the release of growth factors and greater levels of cellular attachment because of the chemical signals involved in the natural immune response.35 Another study found that the use of a certain pore size in the scaffold material led to faster and more complete healing in an in vivo study using rabbits. Upon further investigation, it was found that the smaller pore size was interacting with macrophages involved in the triggered immune response; this interaction ultimately led more macrophages to differentiate into a regenerative pathway, leading to better and faster healing of the implant with the surrounding tissue.36 Similar studies have investigated the effect of methods such as attaching surface proteins with similarly enlightening results. These and other promising studies have led to an increased awareness of chemical signaling as a method to enhance biomaterial integration with larger implications including faster healing time and greater functionality.

Conclusion

The use of scaffolds for tissue engineering has been the subject of much research because of its potential for extensive utilization in the medical field. Recent advancements have focused on several areas, particularly the use of biomolecules, improved vascularization, increases in mechanical strength, and attachment to existing tissue. Advancements in each of these fields have been closely related to the use of scaffolding. Several biomolecules, especially growth factors, have led to a greater ability for tissue to adapt as an integrated part of the body after implantation. These growth factors rely on efficient means of delivery, notably through inclusion in the scaffold, in order to have an effect on the tissue. The development of new methods and refinement of existing ones has allowed researchers to successfully vascularize tissue on multiple types of scaffolds. Likewise, better methods of strengthening engineered tissue scaffolds before cell growth and implantation have allowed for improved functionality, especially under mechanical forces. Modifications to scaffolding and the addition of special molecules have allowed for increased cellular attachment, improving the efficacy of engineered tissue for implantation. Further advancement in each of these areas could lead to more effective scaffolds and the ability to successfully use engineered tissue for functional implants in medical treatments.

References

  1. “Tissue Engineering and Regenerative Medicine.” National Institute of Biomedical Imaging and Bioengineering. N.p., 22 July 2013. Web. 29 Oct. 2016.
  2. Haycock, John W. “3D Cell Culture: A Review of Current Approaches and Techniques.” 3D Cell Culture: Methods and Protocols. Ed. John W. Haycock. Totowa, NJ: Humana Press, 2011. 1–15. Web.
  3. Takahashi, Kazutoshi, and Shinya Yamanaka. “Induction of Pluripotent Stem Cells from Mouse Embryonic and Adult Fibroblast Cultures by Defined Factors.” Cell 126.4 (2006): 663–676. ScienceDirect. Web.
  4. Richardson, Thomas P. et al. “Polymeric System for Dual Growth Factor Delivery.” Nat Biotech 19.11 (2001): 1029–1034. Web.
  5. Liao, IC, SY Chew, and KW Leong. “Aligned Core–shell Nanofibers Delivering Bioactive Proteins.” Nanomedicine 1.4 (2006): 465–471. Print.
  6. Elliott Donaghue, Irja et al. “Cell and Biomolecule Delivery for Tissue Repair and Regeneration in the Central Nervous System.” Journal of Controlled Release: Official Journal of the Controlled Release Society 190 (2014): 219–227. PubMed. Web.
  7. Murphy, Ciara M., Matthew G. Haugh, and Fergal J. O’Brien. “The Effect of Mean Pore Size on Cell Attachment, Proliferation and Migration in Collagen–glycosaminoglycan Scaffolds for Bone Tissue Engineering.” Biomaterials 31.3 (2010): 461–466. Web.
  8. Sachlos, E., and J. T. Czernuszka. “Making Tissue Engineering Scaffolds Work. Review: The Application of Solid Freeform Fabrication Technology to the Production of Tissue Engineering Scaffolds.” European Cells & Materials 5 (2003): 29-39-40. Print.
  9. Chen, Guoping, Takashi Ushida, and Tetsuya Tateishi. “Scaffold Design for Tissue Engineering.” Macromolecular Bioscience 2.2 (2002): 67–77. Wiley Online Library. Web.
  10. Vacanti, Charles A. 2006. “The history of tissue engineering.” Journal of Cellular and Molecular Medicine 10 (3): 569-576.
  11. Depprich, Rita A. “Biomolecule Use in Tissue Engineering.” Fundamentals of Tissue Engineering and Regenerative Medicine. Ed. Ulrich Meyer et al. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. 121–135. Web.
  12. Laiho, Marikki, and Jorma Keski-Oja. “Growth Factors in the Regulation of Pericellular Proteolysis: A Review.” Cancer Research 49.10 (1989): 2533. Print.
  13. Morstyn, George, and Antony W. Burgess. “Hemopoietic Growth Factors: A Review.” Cancer Research 48.20 (1988): 5624. Print.
  14. Yancopoulos, George D. et al. “Vascular-Specific Growth Factors and Blood Vessel Formation.” Nature 407.6801 (2000): 242–248. Web.
  15. Aaronson, SA. “Growth Factors and Cancer.” Science 254.5035 (1991): 1146. Web.
  16. Lawrence, DA. “Transforming Growth Factor-Beta: A General Review.” European cytokine network 7.3 (1996): 363–374. Print.
  17. Mann, Brenda K, Rachael H Schmedlen, and Jennifer L West. “Tethered-TGF-β Increases Extracellular Matrix Production of Vascular Smooth Muscle Cells.” Biomaterials 22.5 (2001): 439–444. Web.
  18. Malafaya, Patrícia B., Gabriela A. Silva, and Rui L. Reis. “Natural–origin Polymers as Carriers and Scaffolds for Biomolecules and Cell Delivery in Tissue Engineering Applications.” Matrices and Scaffolds for Drug Delivery in Tissue Engineering 59.4–5 (2007): 207–233. Web.
  19. Sahoo, Sambit et al. “Growth Factor Delivery through Electrospun Nanofibers in Scaffolds for Tissue Engineering Applications.” Journal of Biomedical Materials Research Part A 93A.4 (2010): 1539–1550. Web.
  20. Novosel, Esther C., Claudia Kleinhans, and Petra J. Kluger. “Vascularization Is the Key Challenge in Tissue Engineering.” From Tissue Engineering to Regenerative Medicine- The Potential and the Pitfalls 63.4–5 (2011): 300–311. Web.
  21. Drury, Jeanie L., and David J. Mooney. “Hydrogels for Tissue Engineering: Scaffold Design Variables and Applications.” Synthesis of Biomimetic Polymers 24.24 (2003): 4337–4351. Web.
  22. Lafage-Proust, Marie-Helene et al. “Assessment of Bone Vascularization and Its Role in Bone Remodeling.” BoneKEy Rep 4 (2015): n. pag. Web.
  23. Türkvatan, Aysel et al. “Multidetector CT Angiography of Renal Vasculature: Normal Anatomy and Variants.” European Radiology 19.1 (2009): 236–244. Web.
  24. Miller, Jordan S. et al. “Rapid Casting of Patterned Vascular Networks for Perfusable Engineered Three-Dimensional Tissues.” Nature Materials 11.9 (2012): 768–774. www.nature.com. Web.
  25. Lovett, Michael et al. “Vascularization Strategies for Tissue Engineering.” Tissue Engineering. Part B, Reviews 15.3 (2009): 353–370. Web.
  26. Cox, Sophie C. et al. “3D Printing of Porous Hydroxyapatite Scaffolds Intended for Use in Bone Tissue Engineering Applications.” Materials Science and Engineering: C 47 (2015): 237–247. ScienceDirect. Web.
  27. Fielding, Gary A., Amit Bandyopadhyay, and Susmita Bose. “Effects of Silica and Zinc Oxide Doping on Mechanical and Biological Properties of 3D Printed Tricalcium Phosphate Tissue Engineering Scaffolds.” Dental Materials 28.2 (2012): 113–122. ScienceDirect. Web.
  28. Engler, Adam J. et al. “Matrix Elasticity Directs Stem Cell Lineage Specification.” Cell 126.4 (2006): 677–689. ScienceDirect. Web.
  29. Bilodeau, Katia, and Diego Mantovani. “Bioreactors for Tissue Engineering: Focus on Mechanical Constraints. A Comparative Review.” Tissue Engineering 12.8 (2006): 2367–2383. online.liebertpub.com (Atypon). Web.
  30. Sommer, Marianne R. et al. “Silk Fibroin Scaffolds with Inverse Opal Structure for Bone Tissue Engineering.” Journal of Biomedical Materials Research Part B: Applied Biomaterials (2016): n/a-n/a. Wiley Online Library. Web.
  31. Sapir-Koren, Rony, and Gregory Livshits. “Bone Mineralization and Regulation of Phosphate Homeostasis.” IBMS BoneKEy 8.6 (2011): 286–300. www.nature.com. Web.
  32. Boehler, Ryan M., John G. Graham, and Lonnie D. Shea. “Tissue Engineering Tools for Modulation of the Immune Response.” BioTechniques 51.4 (2011): 239–passim. PubMed Central. Web.
  33. Follet, H. et al. “The Degree of Mineralization Is a Determinant of Bone Strength: A Study on Human Calcanei.” Bone 34.5 (2004): 783–789. PubMed. Web.
  34. Franz, Sandra et al. “Immune Responses to Implants – A Review of the Implications for the Design of Immunomodulatory Biomaterials.” Biomaterials 32.28 (2011): 6692–6709. ScienceDirect. Web.
  35. Kao, Weiyuan John, and Damian Lee. “In Vivo Modulation of Host Response and Macrophage Behavior by Polymer Networks Grafted with Fibronectin-Derived Biomimetic Oligopeptides: The Role of RGD and PHSRN Domains.” Biomaterials 22.21 (2001): 2901–2909. ScienceDirect. Web.
  36. Bryers, James D, Cecilia M Giachelli, and Buddy D Ratner. “Engineering Biomaterials to Integrate and Heal: The Biocompatibility Paradigm Shifts.” Biotechnology and bioengineering 109.8 (2012): 1898–1911. Web.

Comment

Molecular Mechanisms Behind Alzheimer’s Disease and Epilepsy

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Molecular Mechanisms Behind Alzheimer’s Disease and Epilepsy

Abstract

Seizures are characterized by periods of high neuronal activity and are caused by alterations in synaptic function that disrupt the equilibrium between excitation and inhibition in neurons. While often associated with epilepsy, seizures can also occur after brain injuries and interestingly, are common in Alzheimer’s patients. While Alzheimer’s patients rarely show the common physical signs of seizures, recent research has shown that electroencephalogram (EEG) technology can detect nonconvulsive seizures in Alzheimer’s patients. Furthermore, patients with Alzheimer’s have a 6- to 10-fold increase in the probability of developing seizures during the course of their disease compared to healthy controls.2 While previous research has focused on the underlying molecular mechanisms of Aβ tangles in the brain, the research presented here relates seizures to the cognitive decline in Alzheimer’s patients in an attempt to find therapeutic approaches that tackle both epilepsy and Alzheimer’s.

Introduction

The hippocampus is found in the temporal lobe and is involved in the creation and consolidation of new memories. It is the first part of the brain to undergo neurodegeneration in Alzheimer’s disease, and as such, the disease is characterized by memory loss. Alzheimer’s is different than other types of dementia because patients’ episodic memories are affected strongly and quickly. Likewise, patients who suffer from epilepsy also exhibit neurodegeneration in their hippocampi and have impaired episodic memories. Such similarities led researchers to hypothesize that the two diseases have the same pathophysiological mechanisms. In one study, four epileptic patients exhibited progressive memory loss that clinically resembled Alzheimer’s disease.6 In another study, researchers found that seizures precede cognitive symptoms in late-onset Alzheimer’s disease.7 This led researchers to hypothesize that a high incidence of seizures increases the rate of cognitive decline in Alzheimer’s patients. However, much is yet to be discovered about the molecular mechanisms underlying seizure activity and cognitive impairments.

Amyloid precursor protein (APP) is the precursor molecule to Aβ, the polypeptide that makes up the Aβ plaques found in the brains of Alzheimer’s patients. In many Alzheimer’s labs, the J20 APP mouse model of disease is used to simulate human Alzheimer’s. These mice overexpress the human form of APP, develop amyloid plaques, and have severe deficits in learning and memory. The mice also have high levels of epileptiform activity and exhibit spontaneous seizures that are characteristic of epilepsy.11 Understanding the long-lasting effects of these seizures is important in designing therapies for a disease that is affected by recurrent seizures. Thus, comparing the APP mouse model of disease with the temporal lobe epilepsy (TLE) mouse model is essential in unraveling the mysteries of seizures and cognitive decline.

Shared Pathology of the Two Diseases

The molecular mechanisms behind the two diseases are still unknown and under much research. An early observation in both TLE and Alzheimer’s involved a decrease in calbindin-28DK, a calcium buffering protein, in the hippocampus.10 Neuronal calcium buffering and calcium homeostasis are well-known to be involved in learning and memory. Calcium channels are involved in synaptic transmission, and a high calcium ion influx often results in altered neuronal excitability and calcium signaling. Calbindin acts as a buffer for binding free Ca2+ and is thus critical to calcium homeostasis.

Some APP mice have severe seizures and an extremely high loss of calbindin, while other APP mice exhibit no loss in calbindin. The reasons behind this is unclear, but like patients, mice are also very variable.

The loss of calbindin in both Alzheimer’s and TLE is highly correlated with cognitive deficits. However, the molecular mechanism behind the calbindin loss is unclear. Many researchers are now working to uncover this mechanism in the hopes of preventing the calbindin loss, thereby improving therapeutic avenues for Alzheimer’s and epilepsy patients.

Seizures and Neurogenesis

The dentate gyrus is one of the two areas of the adult brain that exhibit neurogenesis.13 Understanding neurogenesis in the hippocampus can lead to promising therapeutic targets in the form of neuronal replacement therapy. Preliminary research in Alzheimer’s and TLE has shown changes in neurogenesis over the course of the disease.14 However, whether neurogenesis is increased or decreased remains a controversial topic, as studies frequently contradict each other.

Many researchers study neurogenesis in the context of different diseases. In memory research, neurogenesis is thought to be involved in both memory formation and memory consolidation.12 Alzheimer’s leads to the gradual decrease in the generation of neural progenitors, the stem cells that can differentiate to create a variety of different neuronal and glial cell types.8 Further studies have shown that the neural stem cell pool undergoes accelerated depletion due to seizure activity.15 Initially, heightened neuronal activity stimulates neural progenitors to divide rapidly at a much faster rate than controls. This rapid division depletes the limited stem cell pool prematurely. Interestingly enough, this enhanced neurogenesis is detected long before other AD-linked pathologies. When the APP mice become older, the stem cell pool is depleted to a point where neurogenesis occurs much slower compared to controls.9 This is thought to represent memory deficits, in that the APP mice can no longer consolidate new memories as effectively. The same phenomenon occurs in mice with TLE.

The discovery of this premature neurogenesis in Alzheimer’s disease has many therapeutic benefits. For one, enhanced neurogenesis can be used as a marker for Alzheimer’s long before any symptoms are present. Furthermore, targeting increased neurogenesis holds potential as a therapeutic avenue, leading to better remedies for preventing the pathological effects of recurrent seizures in Alzheimer’s disease.

Conclusion

Research linking epilepsy with other neurodegenerative disorders is still in its infancy, and leaves many researchers skeptical about the potential to create a single therapy for multiple conditions. Previous EEG studies recorded Alzheimer’s patients for a few hours at a time and found limited epileptiform activity; enhanced overnight technology has shown that about half of Alzheimer’s patients have epileptiform activity in a 24-hour period, with most activity occurring during sleep1. Recording patients for even longer periods of time will likely raise this percentage. Further research is being conducted to show the importance of seizures in enhancing cognitive deficits and understanding Alzheimer’s disease, and could lead to amazing therapeutic advances in the future.

References

  1. Vossel, K. A. et. al. Incidence and Impact of Subclinical Epileptiform Activity. Ann Neurol. 2016.
  2. Pandis, D. Scarmeas, N. Seizures in Alzheimer Disease: Clinical and Epidemiological Data. Epilepsy Curr. 2012. 12(5), 184-187.
  3. Chin, J. Scharfman, H. Shared cognitive and behavioral impairments in epilepsy and Alzheimer’s disease and potential underlying mechanisms. Epilepsy & Behavior. 2013. 26, 343-351.
  4. Carter, D. S. et. al. Long-term decrease in calbindin-D28K expression in the hippocampus of epileptic rats following pilocarpine-induced status epilepticus. Epilepsy Res. 2008. 79(2-3), 213-223.
  5. Jin, K. et. al. Increased hippocampal neurogenesis in Alzheimer’s Disease. Proc Natl Acad Sci. 2004. 101(1), 343-347.
  6. Ito, M., Echizenya, N., Nemoto, D., & Kase, M. (2009). A case series of epilepsy-derived memory impairment resembling Alzheimer disease. Alzheimer Disease and Associated Disorders, 23(4), 406–409.
  7. Picco, A., Archetti, S., Ferrara, M., Arnaldi, D., Piccini, A., Serrati, C., … Nobili, F. (2011). Seizures can precede cognitive symptoms in late-onset Alzheimer’s disease. Journal of Alzheimer’s Disease: JAD, 27(4), 737–742.
  8. Zeng, Q., Zheng, M., Zhang, T., & He, G. (2016). Hippocampal neurogenesis in the APP/PS1/nestin-GFP triple transgenic mouse model of Alzheimer’s disease. Neuroscience, 314, 64–74. https://doi.org/10.1016/j.neuroscience.2015.11.05
  9. Lopez-Toledano, M. A., Ali Faghihi, M., Patel, N. S., & Wahlestedt, C. (2010). Adult neurogenesis: a potential tool for early diagnosis in Alzheimer’s disease? Journal of Alzheimer’s Disease: JAD, 20(2), 395–408. https://doi.org/10.3233/JAD-2010-1388
  10. Palop, J. J., Jones, B., Kekonius, L., Chin, J., Yu, G.-Q., Raber, J., … Mucke, L. (2003). Neuronal depletion of calcium-dependent proteins in the dentate gyrus istightly linked to Alzheimer’s disease-related cognitive deficits. Proceedings of the National Academy of Sciences of the United States of America, 100(16), 9572–9577. https://doi.org/10.1073/pnas.1133381100
  11. Research Models: J20. AlzForum: Networking for a Cure.
  12. Kitamura, T. Inokuchi, K. (2014). Role of adult neurogenesis in hippocampal-cortical memory consolidation. Molecular Brain 7:13. 10.1186/1756-6606-7-13.
  13. Piatti, V. Ewell, L. Leutgeb, J. Neurogenesis in the dentate gyrus: carrying the message or dictating the tone. Frontiers in Neuroscience 7:50. doi: 10.3389/fnins.2013.00050
  14. Noebels, J. (2011). A Perfect Storm: Converging Paths of Epilepsy and Alzheimer’s Dementia Intersect in the Hippocampal Formation. Epilepsia 52, 39-46. doi:  10.1111/j.1528-1167.2010.02909.x
  15. Jasper, H.; et.al. In Jasper’s Basic Mechanisms of the Epilepsies, 4; Rogawski, M., et al., Eds.; Oxford University Press: USA, 2012

2 Comments

GMO: How Safe is Our Food?

Comment

GMO: How Safe is Our Food?

For thousands of years, humans have genetically enhanced other living beings through the practice of selective breeding. Sweet corn and seedless watermelons at local grocery stores as well as purebred dogs at the park are all examples of how humans have selectively enhanced desirable traits in other living creatures. In his 1859 book On the Origin of Species, Charles Darwin discussed how selective breeding by humans had been successful in producing change over time. As technology improves, our ability to manipulate plants and other organisms by introducing new genes promises both new innovations and potential risks.

Genetically modified organisms (GMOs) are plants, animals, or microorganisms in which genetic material, such as DNA, has been artificially manipulated to produce a certain advantageous product. This recombinant genetic engineering allows certain chosen genes, even those from unassociated species, to be transplanted from one organism into another.1 Genetically modified crops are usually utilized to yield an increased level of crop production and to introduce resistance against diseases. Virus resistance makes plants less susceptible to diseases caused by insects and viruses, resulting in higher crop yields.

Genetic enhancement has improved beyond selective breeding as gene transfer technology has become capable of directly altering genomic sequences . Using a “cut and paste” mechanism, a desired gene can be isolated from a target organism via restriction enzymes and then inserted into a bacterial host using DNA ligase. Once the new gene is introduced, the cells with the inserted DNA (known as “recombinant” DNA) can be bred to generate an advanced strain that can be further replicated to produce the desired gene product.1 Due to this genetic engineering process, researchers have been able to produce synthetic insect-resistant tomatoes, corn, and potatoes. Humans’ ability to modify crops has improved yields and nutrients in a given environment, becoming the keystone of modern agriculture.2 Despite these positive developments, skepticism still exists regarding the safety and societal impact of GMOs.

The technological advancement from selective breeding to genetic engineering has opened up a plethora of possibilities for the future of food. As scientific capabilities expand, ethics and ideals surrounding the invasive nature of the production of GMOs have given rise to concerns about safety and long-term impacts. According to the Center for Food Safety, GMO seeds are used in 90 percent of corn, soybeans, and cotton grown in the United States.2 Because GMO crops are so prevalent, any negative ecological interactions involving a GMO product could prove devastating for the environment.

While the dangers of genetic modification are being considered, genetic engineering has proven to have benefits to human health and the farming industry. Genetically modified foods maintain a longer shelf life, which allows for the safe transport of surplus foodstuffs to people in countries without access to nutrition-rich foods. Genetic engineering has supplemented staple crops with vital minerals and nutrients, , helping fight worldwide malnutrition. For example, Golden rice is a genetically-modified variant of rice that biosynthesizes beta-carotene, a precursor of vitamin A.3 This type of rice is intended to be produced and consumed in areas with a shortage of dietary vitamin A, which is a deficiency that kills 670,000 children each year. Despite the controversial risks, genetic engineering of crops promises to continually increase the availability and durability of food.

References

  1. Learn.Genetics. http://learn.genetics.utah.edu/content/science/gmfoods/ (accessed Sep 20, 2016)
  2. Fernandez-Cornejo, Jorge, and Seth James Wechsler. USDA ERS – Adoption of Genetically Engineered Crops in the U.S.: Recent Trends in GE Adoption. USDA ERS – Adoption of Genetically Engineered Crops in the U.S.: Recent Trends in GE Adoption. https://www.ers.usda.gov/data-products/adoption-of-genetically-engineered-crops-in-the-us/recent-trends-in-ge-adoption.aspx (accessed Sep 30,2016)
  3. Dan Charles. In A Grain Of Golden Rice, A World Of Controversy Over GMO Foods. http://www.npr.org/sections/thesalt/2013/03/07/173611461/in-a-grain-of-golden-rice-a-world-of-controversy-over-gmo-foods (accessed Sep 24, 2016)

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Microbes: Partners in Cancer Research

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Microbes: Partners in Cancer Research

To millions around the world, the word ‘cancer’ evokes emotions of sorrow and fear. For decades, scientists around the world have been trying to combat this disease, but to no avail. Despite the best efforts of modern medicine, about 46% of patients diagnosed with cancer still pass away as a direct result of the disease.1 However, the research performed by Dr. Michael Gustin at Rice University may change the field of oncology forever.

Cancer is a complex and multifaceted disease that is currently not fully understood by medical doctors and scientists. Tumors vary considerably between different types of cancers and from patient to patient, further complicating the problem. Understanding how cancer develops and responds to stimuli is essential to producing a viable cure, or even an individualized treatment.

Dr. Gustin’s research delves into the heart of this problem. The complexity of the human body and its component cells are currently beyond the scope of any one unifying model. For this reason, starting basic research with human subjects would be detrimental. Researchers turn instead to simpler eukaryotes in order to understand the signal pathways involved in the cell cycle and how they respond to stress.2 Through years of hard work and research, Dr. Gustin’s studies have made huge contributions to the field of oncology.

Dr. Gustin studied a species of yeast, Saccharomyces cerevisiae, and its response to osmolarity. His research uncovered the high osmolarity glycerol (HOG) pathway and mitogen-activated protein kinase (MAPK) cascade, which work together to maintain cellular homeostasis. The HOG pathway is much like a “switchboard [that] control[s] cellular behavior and survival within a cell, which is regulated by the MAPK cascade through the sequential phosphorylation of a series of protein kinases that mediates the stress response.”3 These combined processes allow the cell to respond to extracellular stress by regulating gene expression, cell proliferation, and cell survival and apoptosis. To activate the transduction pathway, the sensor protein Sln1 recognizes a stressor and subsequently phosphorylates, or activates, a receiver protein that mediates the cellular response. This signal transduction pathway leads to the many responses that protect a cell against external stressors. These same protective processes, however, allow cancer cells to shield themselves from the body’s immune system, making them much more difficult to attack.

Dr. Gustin has used this new understanding of the HOG pathway to expand his research into similar pathways in other organisms. Fascinatingly, the expression of human orthologs of HOG1 proteins within yeast cells resulted in the same stimulation of the pathway despite the vast evolutionary differences between yeast and mammals. Beyond the evolutionary implications of this research, this illustrates that the “[HOG] pathway defines a central stress response signaling network for all eukaryotic organisms”.3 So much has already been learned through studies on Saccharomyces cerevisiae and yet researchers have recently discovered an even more representative organism. This fungus, Candida albicans, is the new model under study by Dr. Gustin and serves as the next step towards producing a working model of cancer and its responses to stressors. Its more complex responses to signalling make it a better working model than Saccharomyces cerevisiae.4 The research that has been conducted on Candida albicans has already contributed to the research community’s wealth of information, taking great strides towards eventual human applications in the field of medicine. For example, biological therapeutics designed to combating breast cancer cells have already been tested on both Candida albicans biofilms and breast cancer cells to great success.5

This research could eventually be applied towards improving current chemotherapy techniques for cancer treatment. Eventual applications of this research are heavily oriented towards fighting cancer through the use of chemotherapy techniques. Current chemotherapy techniques utilize cytotoxic chemicals that damage and kill cancerous cells, thereby controlling the size and spread of tumors. Many of these drugs can disrupt the cell cycle, preventing the cancerous cell from proliferating efficiently. Alternatively, a more aggressive treatment can induce apoptosis, programmed cell death, within the cancerous cell.6 For both methods, the chemotherapy targets the signal pathways that control the vital processes of the cancer cell. Dr. Gustin’s research plays a vital role in future chemotherapy technologies and the struggle against mutant cancer cells.

According to Dr. Gustin, current chemotherapy is only effective locally, and often fails to completely incapacitate cancer cells that are farther away from the site of drug administration where drug toxicity is highest. As a result, distant cancer cells are given the opportunity to develop cytoprotective mechanisms that increase their resistance to the drug.7 Currently, a major goal of Dr. Gustin’s research is to discover how and why certain cancer cells are more resistant to chemotherapy. The long-term goal is to understand the major pathways involved with cancer resistance to apoptosis, and to eventually produce a therapeutic product that can target the crucial pathways and inhibitors. With its specificity, this new drug would vastly increase treatment efficacy and provide humanity with a vital tool with which to combat cancer, saving countless lives in the future.

References   

  1. American Cancer Society. https://www.cancer.org/latest-new/cancer-facts-and-figures-death-rate-down-25-since-1991.html (February 3 2017).                  
  2. Radmaneshfar, E.; Kaloriti, D.; Gustin, M.; Gow, N.; Brown, A.; Grebogi, C.; Thiel, M. Plos ONE, 2013, 8, e86067.                
  3. Brewster, J.; Gustin, M. Sci. Signal. 2014, 7, re7.
  4. Rocha, C.R.; Schröppel, K.; Harcus, D.; Marcil, A.; Dignard, D.; Taylor, B.N.; Thomas, D.Y.; Whiteway, M.; Leberer, E. Mol. Biol. Cell. 2001, 12, 3631-3643.
  5. Malaikozhundan, B.; Vaseeharan, B.; Vijayakumar, S.; Pandiselvi K.; Kalanjiam R.; Murugan K.; Benelli G. Microbial Pathogenesis 2017, 102, n.p. Manuscript in progress.
  6. Shapiro, G. and Harper, J.; J Clin Invest. 1999, 104, 1645–1653.
  7. Das, B.; Yeger, H.; Baruchel, H.; Freedman, M.H.; Koren, G.; Baruchel, S. Eur. J. Cancer. 2003, 39, 2556-2565.

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The Fight Against Neurodegeneration

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The Fight Against Neurodegeneration

“You know that it will be a big change, but you really don’t have a clue about your future.”A 34-year-old postdoctoral researcher at the Telethon Institute of Genetics and Medicine in Italy at the time, Dr. Sardiello had made a discovery that would change his life forever. Eight years later, Dr. Sardiello is now the principal investigator of a lab in the Jan and Dan Duncan Neurological Research Institute (NRI) where he continues the work that had brought him and his lab to America.

Throughout his undergraduate career, Sardiello knew he wanted to be involved in some manner with biology and genetics research, but his passion was truly revealed in 2000: the year he began his doctoral studies. It was during this year that the full DNA sequence of the common fruit fly was released, which constituted the first ever complete genome of a complex organism. At the time, Sardiello was working in a lab that used fruit flies as a model, and this discovery served to spur his interest in genetics. As the golden age of genetics began, so did Sardiello’s love for the subject, leading to his completion of a PhD in Genetic and Molecular Evolution at the Telethon Institute of Genetics and Medicine. It was at this institute that his team made the discovery that would bring him to America: the function of Transcription Factor EB, colloquially known as TFEB.

Many knew of the existence of TFEB, but no one knew of its function. Dr. Sardiello and his team changed that. In 2009, they discovered that the gene is the master regulator for lysosomal biogenesis and function. In other words, TFEB works as a genetic switch that turns on the production of new lysosomes, an exciting discovery.1 Before the discovery of TFEB’s function, lysosomes were commonly known as the incinerator or the garbage can of the cell, as these organelles were thought to be essentially specialized containers that get rid of cellular waste. However, with the discovery of TFEB’s function, we now know that lysosomes have a much more active role in catabolic pathways and the maintenance of cell homeostasis. Sardiello’s groundbreaking findings were published in Science, one of the most prestigious peer reviewed journals in the scientific world. Speaking about his success, Sardiello said, “The bottom line was that there was some sort of feeling that a big change was about to come, but we didn’t have a clue what. There was just no possible measure at the time.”

Riding the success of his paper, Sardiello moved to the United States and established his own lab with the purpose of defeating the family of diseases known as Neuronal Ceroid Lipofuscinosis (NCLs). NCLs are genetic diseases caused by the malfunction of lysosomes. This malfunction causes waste to accumulate in the cell and eventually block cell function, leading to cell death. While NCLs cause cell death throughout the body, certain specialized cells such as neurons do not regenerate. Therefore, NCLs are generally neurodegenerative diseases. While there are many variants of NCLs, they all result in premature death after loss of neural functions such as sight, motor ability, and memory.

“With current technology,” Sardiello said, “the disease is incurable, since it is genetic. In order to cure a genetic disease, you have to somehow bring the correct gene into every single cell of the body.” With our current understanding of biology, this is impossible. Instead, doctors can work to treat the disease, and halt the progress of the symptoms. Essentially, his lab has found a way using TFEB to enhance the function of the lysosomes in order to fight the progress of the NCL diseases.

In addition to genetic enhancement, Sardiello is also focusing on finding drugs that will activate TFEB and thereby increase lysosomal function. To test these new methods, the Sardiello lab uses mouse models that encapsulate most of the symptoms in NCL patients. “Our current results indicate that drug therapy for NCLs is viable, and we are working to incorporate these strategies into clinical therapy,” Sardiello said. So far the lab has identified three different drugs or drug combinations that may be viable for treatment of this incurable disease.

While it might be easy to talk about NCLs and other diseases in terms of their definitions and effects, it is important to realize that behind every disease are real people and real patients. The goal of the Sardiello Lab is not just to do science and advance humanity, but also to help patients and give them hope. One such patient is a boy named Will Herndon. Will was diagnosed with NCL type 3, and his story is one of resilience, strength, and hope.

When Will was diagnosed with Batten Disease at the age of six, the doctors informed him and his family that there was little they could do. At the time, there was little to no viable research done in the field. However, despite being faced with terminal illness, Will and his parents never lost sight of what was most important: hope. While others might have given up, Missy and Wayne Herndon instead founded The Will Herndon Research Fund - also known as HOPE - in 2009, playing a large role in bringing Dr. Sardiello and his lab to the United States. Yearly, the foundation holds a fundraiser to raise awareness and money that goes towards defeating the NCL diseases. Upon its inception, the fundraiser had only a couple of hundred attendees- now, only half a decade later, thousands of like-minded people arrive each year to support Will and others with the same disease. “Failure is not an option,” Missy Herndon said forcefully during the 2016 banquet. “Not for Will, and not for any other child with Batten disease.” It was clear from the strength of her words that she believed in the science, and that she believed in the research.

“I have a newborn son,” Sardiello said, recalling the speech. “I can’t imagine going through what Missy and Wayne had to. I felt involved and I felt empathy, but most of all, I felt respect for Will’s parents. They are truly exceptional people and go far and beyond what anyone can expect of them. In face of adversity, they are tireless, they won’t stop, and their commitment is amazing.”

When one hears about science and labs, it usually brings to mind arrays of test tubes and flasks or the futuristic possibilities of science. In all of this, one tends to forget about the people behind the test bench: the scientists that conduct the experiments and uncover the next step in the collective knowledge of humanity, people like Dr. Sardiello. However, Sardiello isn’t alone in his endeavors, as he is supported by the members of his lab.

Each and every one of the researchers in Marco’s lab is an international citizen, hailing from at least four different countries in order to work towards a common cause: Parisa Lombardi from Iran, Lakshya Bajaj, Jaiprakash Sharma, and Pal Rituraj from India, Abdallah Amawi, from Jordan, and of course, Marco Sardiello and Alberto di Ronza, from Italy. Despite the vast distances in both geography and culture, the chemistry among the team was palpable, and while how they got to America varied, the conviction that they had a responsibility to help other people and defeat disease was always the same.

Humans have always been predisposed to move forwards. It is because of this propensity that humans have been able to eradicate disease and change the environments that surround us. However, behind all of our achievements lies scientific advancement, and behind it are the people that we so often forget. Science shouldn’t be detached from the humans working to advance it, but rather integrated with the men and women working to make the world a better place. Dr. Sardiello and his lab represent the constant innovation and curiosity of the research community, ideals that are validated in the courage of Will Herndon and his family. In many ways, the Sardiello lab embodies what science truly represents: humans working for something far greater than themselves.

References

  1. Sardiello, M.; Palmieri, M.; di Ronza, A.; Medina, D.L.; Valenza, M.; Alessandro, V. Science. 2009, 325, 473-477.

 

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