It’s estimated that about one third of the world’s population is infected with Tuberculosis. Treatment of Tuberculosis usually involves a combination of antibiotic drugs that often leaves behind drug resistant strains. Dr. Sarah Fortune, an immunologist at the Harvard School of Public Health, and recipient of the NIH Director's New Innovator Award believes that the variation in the growth rate and size of mycobacterial cells (the causative agents of Tuberculosis) is a factor in how receptive the cells are to antibiotics.
Dr. Fortune and colleagues sought to measure the growth and antibiotic susceptibility of mycobacteria at the single cell level. The research team used live cell imaging techniques on fluorescently labeled Mycobacterium smegmatis (which is closely related to Mycobacterium tuberculosis) to observe the cells growing and replicating. The research resulted in the discovery that the Mycobacterium smegmatis cells divided asymmetrically causing diversity in the subpopulation of cells. Noticeably, the divided subpopulation of cells differed in size and growth rate. The physiological differences in the cells led the researchers to speculate about the cells susceptibility to antibiotics. Thus, the subpopulations of cells were treated with various antibiotics. Dr. Fortune and colleagues reported that from the heterogeneous subpopulation of cells some of the cells were inherently tolerant to the antibiotics and some were not. The researchers suggest that the variation of the subpopulation of cells could be an explanation as to why tuberculosis is difficult to cure. This research is a significant step towards understanding the properties and behavior of mycobacteria, which could improve Tuberculosis diagnosis, treatment, and prevention strategies.
Aldridge BB, Fernandez-Suarez M, Heller D, Ambravaneswaran V, Irimia D, Toner M, Fortune SM. Asymmetry and Aging of Mycobacterial Cells Lead to Variable Growth and Antibiotic Susceptibility.Science, 2011.Dec15.PMID: 22174129
Dr. Adah Almutairi, a 2009 NIH Director’s New Innovator awardee, and colleagues at the University of California San Diego, have developed a new type of “smart” polymeric material that may have widespread medical and biological applications. Reported in the journal Macromolecules, the new material disassembles in response to harmless levels of near infrared (NIR) irradiation, which can penetrate up to 10 centimeters (almost 4 inches) into the body. Both the material itself and its breakdown products are well-tolerated by living cells, suggesting this material would potentially be safe for use in humans. This type of material could be used as a capsule for a drug, allowing doctors to only release the drug in a specific area, such as right next to a tumor. It could also be used in tissue engineering, implants, wound-healing, and biosensors. Dr. Almutairi and colleagues are now working on improving the design of this polymeric material, so that it becomes even more sensitive to NIR, allowing a more controlled disassembly of the material. This research is a significant step forward in the development of light-sensitive materials that will allow doctors and researchers to target previously inaccessible sites with precise spatial and temporal control.
Fomina N, McFearin CL, Sermsakdi M, Morachis JM, and Almutairi A. Low power, biologically benign NIR light triggers polymer disassembly. Macromolecules, 2011. 44: 8590-7. PMID: 22096258.
Four Human Microbiome Project (HMP) Investigators Honored by Election to the Institute of Medicine
Four Human Microbiome Project (HMP) Investigators Honored by Election to the Institute of Medicine
Each year, the full membership of the IOM elects up to 65 new members and five foreign associates. Election to the IOM is one of the highest honors bestowed upon professionals in the fields of health and medicine. To be elected, individuals must display outstanding professional achievement and commitment to service. Membership in the IOM reflects the pinnacle of professional achievement. On October 17, 2011 in conjunction with its 41st annual meeting, new members for the class of 2011 were announced. Among the 65 newly elected members are four investigators supported by the NIH Common Fund Human Microbiome Project (HMP).
- Martin J. Blaser, M.D., Frederick H. King Professor of Internal Medicine, chair, department of medicine, and professor of microbiology, New York University School of Medicine, is funded by the HMP to examine and evaluate the cutaneous microbiome in psoriasis.
- Claire M. Fraser-Liggett, Ph.D., director, Institute for Genome Sciences, and professor of medicine, microbiology, and immunology, University of Maryland School of Medicine, has received two awards to study aspects of the human microbiome. She is focusing on the role of the gut microbiota in obesity in the Amish and also analyzing the structure and function of the human gut microbiota in Crohn's disease.
- Richard A. Gibbs, Ph.D., Wofford Cain Professor, department of molecular and human genetics, and director, Human Genome Sequencing Center, Baylor College of Medicine, is funded to develop a microbial genome reference platform for metagenomics.
- David A. Relman, M.D., Thomas M. and Joan C. Merigan Professor, departments of medicine and microbiology and immunology, Stanford University School of Medicine, has been awarded a grant aimed at optimizing a microfluidic device for single bacterial cell genomics.
Epigenomics researchers uncover new chemical modifications on DNA associated proteins
Epigenetic marks are chemical modifications to the genome that regulate which genes are active and which proteins are made in a cell. These marks are found on DNA as well as on the histone proteins that DNA is wrapped around. Epigenetic marks help regulate the expression of genes involved in cell development and function, and are also implicated in a growing number of diseases such as cancer, diabetes, autoimmune diseases, and mental illness (see “A Scientific Illustration of How Epigenetic Mechanisms Can Affect Health”). Drs. Yingming Zhao and Bing Ren, supported in part by the Common Fund’s Epigenomics program, along with their colleagues, have expanded our understanding of epigenetics by identifying a wealth of novel histone modification sites, as well as histone modifications that have never been described before. Using a combination of approaches in the most thorough examination of histones to date, the researchers identified 67 new histone modifications, increasing the number of known histone marks by about 70%. Some of these newly discovered histone marks correspond to types of chemical modifications that had already been described in other regions of histone proteins, but others represent an entirely new type of chemical modification of histones. One such novel modification, lysine crotonylation or Kcr, was found to label regions of the genome that are actively making proteins. In particular, Kcr modifications were found associated with genes that are activated in the testes of male mice at a specific time during development, suggesting that Kcr may regulate genes that are important for aspects of sperm cell maturation and function. The discovery of these new histone modifications expands our understanding of epigenomics, and opens the door to further research into the epigenome that regulates health and disease.
Tan M, Luo H, Lee S, Jin F, Soo Yang J, Montellier E, Buchou T, Cheng Z, Rousseaux S, Rajagopal N, Lu Z, Ye Z, Zhu Q, Wysocka J, Ye Y, Khochbin S, Ren B, and Zhao Y. Identification of 67 histone marks and histone lysine crotonylation as a new type of histone modification. Cell, September 16, 2011. 146: 1016-28. PMID: 21925322.
A major obstacle in the fight against cancer is finding treatments that target and kill only the cancerous cells without damaging healthy cells. Drs. Todd Golub and Stuart Schreiber, supported in part by the Common Fund’s Interdisciplinary Research Consortium for Genomic Based Drug Discovery, along with their colleagues, have discovered a molecule that can selectively kill cancer cells but does not harm normal cells. As reported in the July 14 issue of Nature, this cancer-fighting molecule is piperlongumine, a natural product derived from the plant Piper longum (long pepper). Piperlongumine inhibited tumor growth in mice that were injected with human bladder, breast, lung, or melanoma cancer cells, as well as in mice genetically engineered to develop breast cancer, and it did so more effectively than the chemotherapy drug Taxol (paclitaxel). In both cell cultures and in mice, piperlongumine had no detectable toxic effects on healthy cells, even at extremely high concentrations.
The researchers found that piperlongumine works by targeting a cellular process that differs between cancer cells and normal cells. Cancer cells have a much higher rate of metabolism than normal cells, and consequently they have increased levels of toxic reactive oxygen species (ROS). To tolerate high levels of ROS, cancer cells rely heavily on several different anti-oxidative enzymes that protect against these harmful molecules. Piperlongumine diminishes anti-oxidative enzyme activity, causing ROS levels in cancer cells to increase beyond the threshold for cell death. Normal cells, which have slower metabolic rates and lower levels of ROS, are not as dependent on these anti-oxidative enzymes and so are not harmed by piperlongumine. These exciting results demonstrate a novel strategy for the treatment of cancer by targeting a previously unexplored cellular pathway, and may pave the way for future development of effective cancer drugs with limited side effects.
Raj L, Ide T, Gurkar AU, Foley M, Shenone M, Li X, Tolliday NJ, Golub TR, Carr SA, Shamji AF, Stern AM, Mandinova A, Schreiber SL, and Lee SW. Selective killing of cancer cells by a small molecule targeting the stress response to ROS. Nature 2011; 475(7355):231-4. PMID: 21753854.
The immune system is often thought of as an ally in the fight against invading pathogens that make us sick. But in the attempt to destroy pathogens, sometimes the immune system’s response can be more harmful than the invaders it is trying to defend against. In the 1918 Spanish flu pandemic and the recent avian and swine flu outbreaks, scientists have proposed that an excessive immune reaction flooded patients’ lungs with fluid and disease-fighting cells, contributing to the abnormally high fatality rate. This severe immune reaction involves the production of large amounts of proteins called cytokines, and hence is often called a “cytokine storm.” Because cytokine storm can be deadly, medical interventions aimed at blunting this response are extremely desirable.
Recent work by Dr. Hugh Rosen, a researcher in the Common Fund’s Molecular Libraries and Imaging program, has led to a breakthrough in our understanding of the biological processes underlying cytokine storm. In a study published in the September 16, 2011 issue of Cell, Dr. Rosen and colleagues identify a small molecule compound that blocks cytokine storm and improves survival in mice infected with a strain of influenza virus that is normally fatal. This compound interacts with a protein called S1P1, a receptor on the surface of cells that binds to specific molecules and elicits a cellular response. When the researchers treated influenza-infected mice with the compound, they discovered that the cytokine storm response was diminished and survival was improved. Intriguingly, the researchers also discovered that the cells coordinating cytokine storm were not immune cells or cells from the inner surface of the lungs, as was previously thought. Instead, the cytokine storm was mediated by endothelial cells, which line the inside of blood vessels. These new insights about the role of endothelial cells and the S1P1 protein in the development of the cytokine storm response may help scientists predict which patients are most at risk for this potentially deadly complication, and also suggests potential new therapeutic targets for drug development efforts.
Teijaro JR, Walsh KB, Cahalan S, Fremgen DM, Roberts E, Scott F, Martinborough E, Peach R, Oldstone MBA, and Rosen H. Endothelial cells are central orchestrators of cytokine amplification during influenza virus infection. Cell, September 16, 2011. 146(6):980-991. PMID: 21925319
Iwasaki A and Medzhitov R. A new shield for a cytokine storm. Cell, September 16, 2011. 156(6): 861-2. PMID: 21925310.
Drs. Kang Zhang and Sheng Ding, funded in part by the NIH Director’s Transformative R01 (T-R01) Award program, have unlocked the key to transforming human embryonic stem cells (hESCs) into a type of precursor cell that can be produced in large quantities and has the potential to become many different types of brain cells. Their findings, published in the May 17, 2011 issue of Proceedings of the National Academy of Sciences, represent a huge leap forward in stem cell science. hESCs, with their ability to become any cell type in the human body, hold great potential for repairing or replacing damaged tissues. However, a number of obstacles have prevented hESCs from fulfilling this promise. Scientists have faced challenges finding the right method to change hESCs into more specialized precursor cells, which can self-renew to produce large quantities of cells while also retaining the ability to become many different cell types within a specific tissue. Additionally, hESCs can cause the formation of tumors, which prohibits their use for therapeutic purposes. Drs. Zhang, Ding, and colleagues used a novel combination of small molecules to induce hESCs to become primitive neuronal stem cells (pNSCs), a cell type that can be directed to make many different types of neurons, or brain cells. Unlike hESCs, pNSCs did not induce tumor formation when injected into mice, which opens the door for potential therapeutic use. The researchers coaxed the pNSCs to form the types of neurons damaged by Parkinson’s disease and Lou Gehrig’s disease (amyotrophic lateral sclerosis; ALS), and suggest that pNSCs could be used to make many other types of neurons as well. This same method could be modified to direct hESCs to make other types of stem cells that could then be used to make heart, pancreas, or other tissue types. Future studies will need to examine how these cells could be used to treat a variety of human diseases.
Li W, Sun W, Zhang Y, Wei W, Ambasudhan R, Xia P, Talantova M, Lin T, Kim J, Wang X, Kim WR, Lipton SA, Zhag K, and Ding S. Rapid induction and long-term self-renewal of primitive neural precursors from human embryonic stem cells by small molecules inhibitors. Proceedings of the National Academy of Sciences, 2011 May 17; 108(20): 8299-8304. PMID: 21525408.
The adult mammalian brain contains several specialized areas where stem cells capable of producing new neurons reside. Dr. Chay Kuo, an NIH Director’s New Innovator Award recipient, has identified key components of one such specialized area, or niche, that is critical for the production of new neurons. Published in the July 14, 2011 issue of Neuron, Dr. Kuo and colleagues demonstrate that two proteins, Foxj1 and Ank3, are critical for maintaining the cellular niche around brain stem cells.
Foxj1 is a transcription factor, a type of protein that regulates when and where other genes are expressed. Within the stem cell niche studied by Dr. Kuo, the Foxj1 protein causes the Ank3 protein to be expressed. The Ank3 protein then helps assemble groups of ependymal cells, a type of cell that surrounds the brain stem cells and provides support for the production of new neurons. Without Foxj1 and Ank3 proteins, the niche is disrupted and stem cells fail to produce new neurons.
Currently, when neural stem cells are studied in the laboratory, they are not surrounded by these ependymal cells. Under these conditions, it is extremely difficult to make the stem cells produce neurons. The findings of Dr. Kuo and colleagues suggests that in the laboratory setting, scientists may need to recreate the same kind of support provided by ependymal cells in the brain stem cell niche. By understanding the local cellular environment that helps support production of new neurons, researchers hope to improve future therapeutic strategies that use stem cells to produce neurons for repairing or replacing damaged tissue.
Paez-Gonzalez P, Abdi K, Luciano D, Liu Y, Soriano-Navarro M, Rawlins E, Bennett V, Garcia-Verdugo JM, and Kuo CT. Ank3-dependent SVZ niche assembly is required for the continued production of new neurons. Neuron, July 14, 2011. 71: 61-75. PMID: 21745638.
Biomedical research data generated from genomics analyses, imaging, biochemistry and other assays are abundant yet difficult to integrate using conventional approaches and databases. To address this need, Dr. Peter Sorger and colleagues at Harvard Medical School, Massachusetts Institute of Technology, and the University of Applied Sciences in Germany, researchers supported through the Common Fund’s Library of Integrated Network Based Cellular Signatures (LINCS) program, have developed an innovative new adaptable method that allows different types of complex data sets to be stored, analyzed and extended. In a recent paper in Nature Methods, they demonstrate the utility of the approach, which exploits useful aspects of two data file formats (HDF5 and XML), for analyzing a complex imaging data set reflecting 160 experimental conditions in over a million different single cells. The approach led to the discovery of new pharmacological relationships between compounds that bind and inhibit epidermal growth factor receptors (EGFR), providing insights into cell-to-cell variability in response to drugs.
Millard BL, Niepel M, Menden MP, Muhlich JL, and Sorger PK. Adaptive informatics for multifactorial and high-content biological data. Nat Methods. 2011. Vol 8(6):487-493.
Researchers supported by the Molecular Libraries and Imaging program have helped to develop a novel chemical that blocks TH17 cells, immune cells implicated in numerous autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease. Dr. Patrick Griffin and colleagues from the Scripps Research Institute Molecular Screening Center published a study in the April 28, 2011 issue of Nature describing SR1001, a new compound that blocks the development of TH17 cells and slows disease progression in a mouse model of multiple sclerosis. TH17 cells are part of the body’s natural defense against disease-producing pathogens. However, in some autoimmune disorders, the inflammatory chemicals, or cytokines, produced by TH17 cells harm the body’s own tissues. SR1001 blocks TH17 cells by interfering with the action of two proteins critical for TH17 cell development, called RORα and RORγt. When SR1001 blocks the action of RORα and RORγt in the precursors to TH17 cells, these cells can no longer develop into TH17 cells and do not produce the cytokines normally produced by functioning TH17 cells. Treatment with SR1001 delays disease onset and reduces the severity of symptoms in a mouse model of multiple sclerosis, a well-studied model for TH17-mediated autoimmune disease. These results suggest an exciting new way to target several different autoimmune disorders in which TH17 cells play a role.
Solt LA, Kumar N, Nuhant P, Wang Y, Lauer JL, Liu J, Istrate MA, Kamenecka TM, Roush WR, Vidovic D, Schurer SC, Xu J, Wagoner G, Drew PD, Griffin PR, and Burris TP. Suppression of TH17 differentiation and autoimmunity by a synthetic ROR ligand. Nature, April 28, 2011. 472: 491-494. PMID: 21499262. Jetten AM. Immunology: A helping hand against autoimmunity. Nature, April 28, 2011. 472: 421-422. PMID: 21525918
Researchers in the Common Fund’s Structural Biology program are changing the way companies are thinking about designing new drugs -- by using 3-D images of membrane proteins in cells to help identify and screen potential drug molecules. Membrane proteins span the membrane of cells and provide a pathway for signals outside the cell to be transmitted inside. G-protein-coupled receptors (GPCRs) are an important class of membrane proteins involved in many different biological pathways that are essential to health and response to therapeutics. Although almost 40% of all drugs on the market target GPCR signaling pathways, drug discovery remains slow and arduous because membrane proteins are very difficult to isolate, stabilize, and characterize structurally. Understanding the 3-D structure of a membrane protein can accelerate the discovery process because it shows all the “pockets” of the protein where molecules or drugs can bind and change how the protein signals to the inside of the cell. The structures can be used to test how a specific GPCR changes when it is bound by different molecules that may turn “on” or “off” the receptor. While pharmaceutical companies are eager to get hold of 3-D crystal structures for GPRCs for use in drug discovery, they often find it difficult. A new trend reported in Chemical and Engineering News (March 14, 2011) shows drug companies are teaming up with academic researchers who have worked out these 3-D structures to overcome this problem.
Dr. Raymond Stevens and colleagues at the Scripps Research Institute, funded through the Structural Biology Program, have perfected a technique to stabilize and characterize the 3-D crystal structure of several GPCRs, including most recently, the A2A adenosine (A2A) receptor involved in control of inflammation and oxygen and blood flow through the heart. As reported in Sciencexpress (March 2011), the team developed an approach to stabilize the A2A receptor and then determine its 3-D crystal structure while a small “activator” molecule was bound to it. The structure provides a view into how GPCRs become activated when bound by a specific small molecule. Having this 3-D structure for the A2A receptor enables drug companies to prioritize which small molecules to test first, for similar activity, during drug discovery. A company co-founded by Dr. Stevens adopted this technique and used it to successfully determine the structure of another GPCR, sphingosine-1-phosphate receptor subtype 1 (S1P1), involved in multiple sclerosis, a degenerative disease of the nervous system. Recently, they identified a small molecule derived from a chemical “hit” discovered through the Common Fund’s Molecular Libraries and Imaging Program which effectively binds to and activates S1P1. The molecule is being tested further as a potential new therapy for multiple sclerosis. The synergy between the two programs, Structural Biology and Molecular Libraries and Imaging, represents a growing trend in partnerships between academic and private sector researchers to tackle difficult problems in drug discovery.
Read the news articles….
- Read more about the drug discovery process for RP1063...
- Read more about the Structural Biology program...
- Read more about the Molecular Libraries and Imaging Program...
Several psychiatric disorders, including attention deficit hyperactivity disorder (ADHD), drug and alcohol addiction, and schizophrenia, are characterized by poor impulse control and difficulty inhibiting certain behaviors. These traits are referred to as behavioral inflexibility, which is thought to be partially under genetic control. However, the genes responsible have been difficult to identify in humans. In a paper available online March 10, 2011 in the journal Biological Psychiatry, researchers in the Common Fund’s Interdisciplinary Research program’s Consortium for Neuropsychiatric Phenomics report that they have identified several genes associated with behavioral inflexibility in mice, and that these findings might be applicable to humans as well. To identify genes that underlie behavioral inflexibility, Dr. David Jentsch and colleagues from the University of California Los Angeles and the University of Tennessee first tested 51 genetically different strains of mice for the ability to reverse their behavior in a learned task. To successfully complete this task, mice had to learn to poke their nose into an opening either on the left or right side of the cage in order to receive a food reward. Once the mice mastered this skill, they had to unlearn which side to poke their nose into, and re-learn to poke their nose on the opposite side. The number of tries it takes a mouse to reverse its behavior indicates how much behavioral flexibility and impulse control the mouse has. The researchers reasoned that by looking at both the genes and behaviors of the mice, they could find genetic differences that were associated with the behavioral differences. Indeed, the researchers zeroed in on a region of the mouse chromosome 10 that contains several genes that influence behavioral flexibility. One gene, Syn3, regulates chemical communication in the brain and has been inconclusively linked to schizophrenia in humans. Another gene, Nt5dc3, is a gene of unknown function that has been associated with ADHD. The current research suggests that both of these genes should be investigated further to discover what role they may play in human psychiatric disorders, and also demonstrates a new way to use mouse behavior and genetics to find genes that may contribute to complex behaviors in humans.
Laughlin RE, Grant TL, Williams RW, Jentsch JD. Genetic dissectioin of behavioral flexibility: reversal learning in mice. Biological Psychiatry, 2011 June 1; 69(11): 1109-16. Epub 2011 March 9. PMID: 21392734.
Shortening the time required to treat tuberculosis (TB) is key to reducing the development of drug resistance and lowering worldwide rates of TB infection and mortality. Reducing treatment duration however depends on: (1) understanding how Mycobacterium tuberculosis (Mtb), the bacteria that causes TB in humans, becomes tolerant to antibiotics; and (2) devising ways to prevent or overcome drug tolerance. NIH Director’s Pioneer Award recipient Dr. Lalita Ramakrishnan and colleagues at the University of Washington, in collaboration with Dr. Paul Edelstein at the University of Pennsylvania, report in a study appearing in the April 1, 2011 issue of Cell, that the development of drug tolerance in Mtb is due in part to the activity of “efflux” pumps in the cell membrane that presumably flush away any antibiotic agents that penetrate the Mtb cells. The authors found that these pumps are stoked into action by host cells called macrophages that are, ironically, part of the body’s frontline defenses against foreign invaders. Based on these findings, the study authors suggest that expanding treatment to include medications that inhibit these pumps could dramatically shorten the time needed to cure infection. While Mtb can infect many body tissues and organs, it primarily attacks the lungs. Once inside the lungs, the bacteria infect the aforementioned macrophages. The macrophages and other types of immune cells respond by aggregating into structures called granulomas which are thought to contain the spread of persistent pathogens. Having taken up residence within macrophages, some populations of Mtb cells quickly become tolerant to anti-TB drugs. Nearly all models of Mtb drug tolerance postulate that this temporary resistance to antibiotics arises when the bacterial cells enter a dormant state in which they stop replicating. Because most antibiotics are only effective against bacterial cells that are reproducing, dormant cells are effectively resistant to antimicrobial agents. In their latest paper however, Dr. Ramakrishnan and colleagues report finding multi-drug tolerant Mtb populations that were actively growing and reproducing inside of host macrophages suggesting that residence within macrophages rapidly induces tolerance. The study authors also found that, having infected macrophages, the Mtb cells deploy effNovel Blood ux pumps that are essential for the Mtb cells to grow within the macrophages and may be used by the bacterial cells to remove toxic substances such as antimicrobial agents. In addition to expanding our understanding of the pathogenesis of TB and drug tolerance, these findings suggest that inhibiting the activity of macrophage-induced bacterial efflux pumps using currently available drugs such as verapamil may be an effective means of reducing the duration of TB treatment. Shorter treatment is likely to translate into increased adherence which will in turn slow the development of multi-drug resistance, reduce transmission of infection to new hosts, and reduce TB-associated mortality around the world.
Adams KN, Takaki K, Connolly LE, Wiedenhoft H, Winglee K, Humbert O, Edelstein PH, Cosma CL, Ramakrishnan L. Drug tolerance in replicating mycobacteria mediated by a macrophage-induced efflux mechanism. Cell, 2011 April 1; 145(1): 39-53. PMID: 21376383.
New discoveries in stem cell biology are fueling the development of new cell-based therapies for diseases such as Parkinson’s and diabetes where tissues may become diseased or damaged. Before this potential can be reached, an important, yet unanswered question is whether adult cells that are “induced” to become like embryonic stem cells – so called induced pluripotent stem cells (iPS cells) -- are actually equivalent to embryonic stem cells and can be used in cell-based therapies. Researchers in the Common Fund’s Epigenomics program are tackling this question. In the February 3, 2011 issue of Nature, Dr. Joseph Ecker and colleagues at the Salk Institute investigated this question by comparing the pattern or “fingerprint” of DNA modifications made by the attachment of a methyl group to a specific DNA base across the genome in iPS cells, human embryonic stem cells, and iPSCs that are coaxed to “return to adulthood.” They found that pattern of DNA methylation for iPS cells is different from true human embryonic stem cells, especially in the middle and ends of the chromosome. At other locations along the genome, the DNA methylation pattern in the iPS cells was similar to that of the adult cells and was retained when the iPS cells were converted back to their “adult” state. Because DNA methylation helps to control gene activity in a cell, the differences in methylation pattern across cell types signal that iPS cells may have a unique molecular “identity” compared to embryonic stem cells. Understanding these differences between iPS and embryonic stem cells is an important step toward harnessing the potential of iPS cells to treat injury and disease.
Lister R, Pelizzola M, Kida YS, Hawkins RD, Nery JR, Hon G, Antosiewicz-Bourget J, O’Malley R, Castanon R, Klugman S, Downes M, Yu M, Stewart R, Ren B, Thomson JA, Evans RM, and Ecker JR. Hotspots of aberrant epigenomic reprogramming in human induced pluripotent stem cells. Nature. Mar 2011. 471:68–73. PMID: 21289626
Researchers in the Common Fund’s Molecular Libraries and Imaging program are tackling a tough biological problem—finding potential drug candidates that target G protein-coupled receptors (GPCRs). Dr. Hugh Rosen, funded in part by the Molecular Libraries and Imaging program, is a scientific founder of Receptos, Inc., a GPCR drug discovery and development company. GPCRs are proteins found on the cell membrane that transmit signals from the outside of the cell to elicit responses inside the cell. GCPRs play many important roles in the body, including hormone signaling, cellular communication in the brain, vision, and cardiac function. Because GPCRs are crucial to many biological processes, they are also implicated in a number of different diseases. One such GPCR, called sphingosine-1-phosphate receptor 1 (S1P1), plays a role in multiple sclerosis, an inflammatory and autoimmune disease which causes damage to the protective myelin sheaths of nerve cells and to the underlying nerve fibers. The current focus of Receptos, Inc. is to conduct clinical trials for a novel compound that targets S1P1, called RPC1063, in the hopes that this potential treatment will suppress circulating immune cells to blunt the underlying cause of multiple sclerosis. The discovery of this novel compound originated from the Molecular Libraries and Imaging program. The first phase 1 clinical safety study of RPC1063 was launched in January 2011, and Phase 2 Proof of Concept studies are expected in 2012. This research has the potential to improve the treatment of multiple sclerosis, and many other diseases that involve signaling by GPCRs.
Reddy MM, Wilson R, Wilson J, Connell S, Gocke A, Hynan L, German D, Kodadek T. Identification of candidate IgG biomarkers for Alzheimer’s disease via combinatorial library screening. Cell, 2011 Jan 7; 144(1): 132-42. PMID: 21215375.
While simple blood tests can accurately and efficiently screen for some diseases, such as diabetes, the lack of blood tests for the majority of diseases can result in delayed or incorrect diagnoses. To overcome this diagnostic obstacle, Dr. Thomas Kodadek, a researcher at The Scripps Research Institute and funded in part by an NIH Director’s Pioneer Award, has developed a novel screening method that could detect disease-associated proteins in the blood of patients with a variety of conditions. In the January 7, 2011 edition of the journal Cell, Dr. Kodadek and colleagues describe their technique for using a collection of synthetic molecules to detect the presence of unique proteins in the blood of diseased individuals that do not appear in the blood of healthy individuals. By screening blood samples from mice with multiple sclerosis, the researchers identified several molecules in their synthetic collection that would only bind to proteins in the blood of the diseased mice, and could distinguish between “patient” mice and normal, healthy mice. Importantly, the researchers went on to demonstrate that in samples from humans, they could use the same technique to identify different molecules that bound to proteins uniquely present in the blood of patients with Alzheimer’s disease. This same binding did not occur in samples from healthy people of similar ages or in patients with another neurodegenerative disorder, Parkinson’s disease. These promising results suggest that this type of blood test has the potential to screen for a wide variety of different diseases, including diseases that currently lack a reliable diagnostic test.
Reddy MM, Wilson R, Wilson J, Connell S, Gocke A, Hynan L, German D, Kodadek T. Identification of candidate IgG biomarkers for Alzheimer’s disease via combinatorial library screening. Cell, 2011 Jan 7; 144(1): 132-42. PMID: 21215375.