Common Fund Highlights
A Change of Heart? Uncovering Sex Differences in Cardiac Neurochemistry
SPARC1 projects are mapping the innervation of organs and tissues, and identifying new targets for future neuromodulation therapies
Although cardiovascular disease is a leading cause of death in women in the US, most research studies have only focused on male animals. One team of researchers in the NIH Common Fund’s Stimulating Peripheral Activity to Relieve Conditions (SPARC) program is helping to change this by including female animals in their cardiovascular research studies.
The team at SPARC awardee institution Oregon Health & Science University, led by Dr. Beth Habecker, generated data from both female and male rats to help map cardiac neurochemistry—the chemical signals produced by nerves to influence heart function—across different tissues. They measured gene expression levels (measurements of molecules encoded by genes) in the stellate ganglion nerve cells that send electrical signals to the heart, and the levels of neurotransmitters (chemical signals transmitted by nerves) within the heart. Establishing these baseline values was critical to understanding how female and male hearts were different, and how they were the same.
The researchers discovered a number of differences between females and males. For example, stellate ganglia in female rats had lower expression of a gene that helps decrease heart rate and blood pressure. Surprisingly, female hearts had higher levels of the neurotransmitter norepinephrine than male hearts, despite identical levels of the molecules that control production of norepinephrine in female and male stellate ganglia. Norepinephrine increases heart rate and blood pressure, and higher levels in female hearts could contribute to development of cardiovascular disease, which is increasingly understood to differ between women and men. These findings highlight the continued need to include both sexes in research studies, and to carefully analyze both the target organs and the nerves that carry signals to-and-from them to develop a more complete understanding of health and disease.
Learn more about the NIH Policy on Sex as a Biological Variable.
Reference: Sex differences in sympathetic gene expression and cardiac neurochemistry in Wistar Kyoto rats. Bayles RG, Tran J, Olivas A, Woodward WR, Fei SS, Gao L, Habecker BA. PLoS One. 2019 Jun 13; 14(6):e0218133.
Where is the butter? Connecting fats and Alzheimer’s disease
Patients with Alzheimer’s disease (AD) often also have symptoms of other diseases, such as diabetes or heart disease. Many of these conditions are heavily impacted by how our bodies metabolize (process or use) the fats, or lipids, our bodies need for everyday functions. In addition, many of the more than 20 genetic risk factors linked to AD can also impact how our bodies use or modify lipids. These findings support the idea that changes in the way our bodies metabolize lipids may contribute to not only the development of AD, but also to how the disease develops in different patients.
Research supported by the Common Fund Metabolomics program aimed to test the idea that distinct lipids are altered both in early and late phases of AD. Metabolomics is a way to identify and measure biological molecules, like lipids, that are created, processed, or consumed during cell metabolism. By identifying key metabolomic changes at different stages in AD development, researchers may be able to pinpoint critical steps in how the disease begins and advances. The researchers used metabolomic experiments to test samples (collected by the Alzheimer’s Disease Neuroimaging Initiative(link is external)) for differences in AD-related lipids in the blood of people with different stages of AD. Depending on the AD stage, they found significant alterations in lipids that led to biochemical changes. For example, in earlier stages of AD, one type of lipid was associated with the accumulation of a hallmark AD protein, tau; however, this lipid was not found in later phases of AD even as tau continues to accumulate. Findings such as these present researchers with new ideas for therapeutic strategies to target different biochemical and metabolomic pathways in our bodies. While promising, future studies are needed to determine the full effect of genetic mutations, diet, and lifestyle on these pathways and how they can be used to predict or treat AD.
Sets of coregulated serum lipids are associated with Alzheimer’s disease pathophysiology. Barupal DK, Baillie R, Fan S, Saykin AJ, Meikle PJ, Arnold M, Nho K, Fiehn O, Kaddurah-Daouk R, & Alzheimer Disease Metabolomics Consortium. Alzheimers & Dementia, 11 (2019) 619-627.
Are There Cellular Checkpoints on the Road to Cancer?
One of the key events during cancer metastasis is a process called the epithelial-to-mesenchymal transition (EMT). EMT occurs when genetic changes allow tumor cells to break away and move into different body regions, potentially leading to new tumors in the body. Previous experiments identified specific “stages” of EMT based on the activity of a small number of genes. However, several new studies indicate these stages may not be as distinct as previously thought. Understanding how EMT occurs is a fundamental goal of cancer biology, as it may lead to new cancer treatment options. The Common Fund 4D Nucleome (4DN) program is primed to help by providing scientists with the tools and resources to monitor the changes in gene activity from groups of cells in tumors as well as small changes in individual cells.
4DN program researchers used advanced techniques to look at gene activity over time in single cells. Instead of finding distinct stages linked to EMT, they showed that EMT is actually a continuum of changes within the cell, with multiple genes getting turned on or off at different times. Many of these genes control how our cells make specific proteins that help hold cells in place. By turning these genes off, it may allow tumor cells to break free and move to new regions within the body. The findings also showed why previous experiments indicated EMT occurred in discrete stages. The researchers discovered “checkpoints” within the continuum where different factors regulate how a cell proceeds through the EMT. If any regulatory factors were disrupted, the progress through EMT could stall, making it look as though there were discrete stages to EMT. It was only by looking at single cells over time that the 4DN researchers could explore the continuum of changes and the factors regulating them without being confused by combined results from large groups of cells. These findings begin to shed light on the genetic changes that govern not only EMT in cancer, but diverse biological processes in development and disease. By learning more about the driving forces behind EMT, researchers can start to explore new cancer treatments that prevent or slow metastasis.
A pooled single-cell genetic screen identifies regulatory checkpoints in the continuum of the epithelial-to-mesenchymal transition. McFaline-Figueroa JL, Hikk AJ, Qui X, Jackson D, Shendure J, Trapnell C. Nature Genetics, 51, 2019, 1389-1398.
A New Way to Spell Life?
All life on earth contains DNA, which houses the chemical building blocks (or nucleic acids) adenine (A), cytosine (C), thymine (T) and guanine (G). These four nucleic acids store information within the DNA, but whether systems with different numbers or types of building blocks can also support life is an open question. Transformative Research Awardee, Dr. Steven Benner, and his team have, for the first time, built a DNA code out of eight letters, challenging traditional ideas about the nature of life and creating new possibilities for information storage.
To explore whether the DNA alphabet could be expanded, researchers used synthetic biology to design four additional nucleic acids that behaved like the original A, C, T and G. When all eight building blocks were combined, they formed a new construct the researchers termed “hachimoji DNA,” based on Japanese words for ‘eight’ (“hachi”) and ‘letters’ (“moji”) which appropriately describe this novel genetic code. The team then tested whether hachimoji DNA adhered to basic principles necessary to support life. First, they established that the set of bases faithfully bound to each other in a predictable pattern, demonstrating they could act as an information storage system. Second, they showed the overall DNA structure was retained even when the bases were reordered, proving the structure was both stable and changeable. Finally, the team confirmed the synthetic DNA could be copied into a functional RNA molecule, a process necessary for transmitting information. Taken together, the experiments demonstrated an eight-letter genetic code could potentially support life as we know it.
These initial studies are only a starting point, and more work is necessary to determine how similar this synthetic DNA is to natural DNA. For example, researchers still need to confirm whether hachimoji DNA can be replicated like natural DNA. However, the hachimoji DNA was able to accurately store and transmit information, showing the technology has potential applications for the storage and retrieval of digital data. Ultimately, the study is a first step in envisioning other types of “living” structures that might exist outside of earth.
Reference: Hachimoji DNA and RNA: A genetic system with eight building blocks. Hoshika S, Leal NA, Kim MJ, Kim MS, Karalkar NB, Kim HJ, Bates AM, Watkins NE Jr, SantaLucia HA, Meyer AJ, DasGupta S, Piccirilli JA, Ellington AD, SantaLucia J Jr, Georgiadis MM, & Benner SA. Science 2019 Feb 22;363(6429):884-887.
In the News:
- Four new DNA letters double life’s alphabet
- DNA Gets a New—and Bigger—Genetic Alphabet
The New York Times
Slide-seq: A Novel Method to Map Tissue Cells
In the same way the world's continents are made up of countries that each contain multiple cities, your body's organs are made up of tissues which each contain multiple cell types. Tissue functions are influenced by the different cell types and their organization, gene activity patterns, and the molecular pathways they use to communicate with other cells. In recent years, detailed explorations of tissue function have been limited by an inability to map where and how individual cells function within the tissue. To address these limitations, Early Independence Awardee, Dr. Fei Chen, and New Innovator Awardee, Dr. Evan Macosko, teamed up to develop Slide-seq, a new method for mapping detailed data on which genes are turned on or off within individual cells.
The technology works like this: First, a surface is packed with DNA-barcoded beads. Next, fresh-frozen tissue is transferred on top of this surface and any RNA released is captured by the beads. RNA is used to measure gene expression— which genes are active in a cell. Scientists can use patterns of gene expression to tell the difference between cell types. Finally, by combining gene expression data with position information from the individual beads, the scientists created a high-resolution map of the spatial position of different cell types. The technique was validated with multiple tissues including those from the brain, liver, and kidney. The team confirmed that RNA expression measurements using Slide-seq agreed with other widely-used methods. To demonstrate its potential, the researchers used Slide-seq to map previously unknown gene expression patterns in an area of the mouse brain that had not been detected using existing technologies. They also used their novel technique to quantify different cellular responses in a mouse model of traumatic brain injury (TBI) over hours, days, and weeks. Their results suggested that TBIs can affect neural activity in a large area surrounding the injury for days or weeks post trauma.
Slide-seq technology may offer a better understanding of how different cell types organize themselves in space. This could allow us to map cells that are important after TBIs and other medically important events. However, more work is required to determine the significance of this organizational structure and how it changes over time. As part of this work, the NIH Common Fund's Human Biomolecular Atlas Program (HuBMAP) is developing an open, global research platform to map cells in healthy human bodies. Dr. Macosko joined the HuBMAP team in September of 2019 and will use Slide-seq to help create maps of the cell types and tissues that make up our bodies' "cities" and "countries."
Reference: Slide-seq: A Scalable Technology for Measuring Genome-Wide Expression at High Spatial Resolution.. Rodriques SG, Stickels RR, Goeva A, Martin CA, Murray E, Vanderburg CR, Welch J, Chen LM, Chen F, & Macosko EZ. Science. 2019 Mar 29;363(6434):1463-1467
How Much Does It Hurt (Exactly)?
Left untreated, pain can have major negative effects on sufferers’ quality of life. However, quantifying pain is complicated because it is a subjective feeling that can reflect both actual and perceived biological damage. Dr. Alexander Niculescu, a NIH New Innovator Awardee, is working on an approach to objectively evaluate pain perception using a simple blood draw. He and his team set out to determine if biological indicators of pain exist—pain biomarkers. More specifically, he was interested in those detectable in the blood. The researchers focused their efforts on a cohort of psychiatric patients; as a group, psychiatric patients are at higher risk for pain disorders and often have an increased perception of pain.
During each of approximately six visits, Dr. Niculescu and his team asked participants to rate their pain as high or low. They also drew the participants’ blood and measured the activity levels of different genes. By associating differences in gene activity levels with high-pain or low-pain over time, the researchers identified 65 potential pain biomarkers. After prioritizing and validating potential biomarkers, the team analyzed their ability to predict a high pain state in a second cohort of psychiatric patients. They found (when separated by gender and diagnosis) individual biomarkers were better predictors than the full 65 biomarker panel. The researchers suggest that for the approach to be most useful, biomarkers may need to be personalized for each individual to accurately determine their pain level..
While this study exclusively focused on participants with psychiatric disorders, the researchers hope that its findings could be generalizable to other populations. Although we are still a long way from being able to accurately quantify pain, this approach demonstrates the potential of precision medicine for its diagnosis and treatment.
Reference: Towards precision medicine for pain: diagnostic biomarkers and repurposed drugs. Niculescu AB, Le-Niculescu H, Levey DF, Roseberry K, Soe KC, Rogers J, Khan F, Jones T, Judd S, McCormick MA, Wessel AR, Williams A, Kurian SM, & White FA. Mol Psychiatry. 2019 Apr;24(4):501-522.
Scientists Discuss Recommendations for Returning Individual genetic research results in African genomic research
There is an ongoing discussion among the scientific community, policymakers, and research participants about how to return a finding concerning an individual research participant’s health that was discovered in the course of conducting genetic research.
In most African countries, where resources are limited, the option to return individual research results (IRRs) to research participants is not always feasible. Furthermore, African populations are more genetically diverse than other populations, and this diversity remains to be fully understood, which poses limitations on the identification of disease-related DNA changes that are more likely to be found in populations of African descent.
In a commentary published in Nature Genetics, Human Heredity and Health in Africa (H3Africa) researchers discuss strategies and challenges that should be addressed to develop policies and practices for returning IRRs in Africa.The researchers propose that there is a need to develop a priority list of genes and mutations that are clinically relevant in African populations. For example, known mutations that cause Sickle Cell Disease, an inheritable disorder where red blood cells to have a distorted shape like a sickle or banana, should be considered a reportable finding in countries where the frequency of the disease is high, and genetic testing is not routinely performed. In some instances, providing an individual with this level of information could inform important personal decisions around marriage and reproduction. The team also proposed several ways to overcome challenges around returning IRRs in Africa, such as increasing the number of healthcare workers with experience in medical genetics. The H3Africa Consortium, supported by the NIH Common Fund, is taking steps to help resolve this issue by offering basic genetic counselling training to nurses across the continent. This commentary adds to the conversation around guidelines for returning IRRs from genomics research and approaches to improve healthcare in Africa.
Returning incidental findings in African genomics research. Wonkam A, de Vries J. Nat Genet. 2019 Nov 25. doi: 10.1038/s41588-019-0542-4
Signature Improvement: Decoding Breast Cancer Drug Targets
A study from the NIH Common Fund’s Library of Integrated Network-based Cellular Signatures (LINCS) program has uncovered why some metastatic breast cancer drugs may work better than others. Metastatic breast cancer, also called ‘Stage 4’ breast cancer, occurs when the cancer has spread to other parts of the body such as the lungs, liver, bones, or brain. A team at LINCS awardee institution Harvard Medical School, led by Dr. Peter Sorger, and their collaborators analyzed three drugs (palbociclib, robociclib, and abemaciclib) that work by blocking a cancer cell’s ability to grow and multiply. All three drugs were thought to function in a similar way, but it was unclear whether each drug may also have unique differences in how they block cancer cells that might affect which drug should be chosen to treat different patients.
The researchers used LINCS tools (including Growth Rate Inhibition metrics, CMap, and Enrichr) and analyses at the RNA, protein, and cellular levels to generate a composite ‘drug signature’ for how each of the drugs affected the cancer cells—like a snapshot of how the cells responded to treatment. Interestingly, they found that one of the drugs (abemaciclib) had a broader range of molecular targets that may make it a good candidate for treating breast cancers that have become resistant to therapy. Further, they showed that abemaciclib treatment of one patient’s drug-resistant metastatic breast cancer decreased the size of a cancer lesion in the patient’s liver. This research highlights how drug signatures may help tailor treatment to improve patient outcomes and identifies targets for developing effective and longer lasting treatments for drug-resistant metastatic breast cancers.
The data sets generated by this research are available in the HMS LINCS Database and are freely available for research use.
Reference: Multiomics Profiling Establishes the Polypharmacology of FDA-Approved CDK4/6 Inhibitors and the Potential for Differential Clinical Activity. Hafner M, Mills CE, Subramanian K, Chen C, Chung M, Boswell SA, Everley RA, Liu C, Walmsley CS, Juric D, Sorger PK. Cell Chem Biol. 2019 Aug 15; 26(8):1067-1080.
Identifying Zip Codes and Contents of Molecular Packages
Extracellular vesicles (EVs) produced by cancer cells are particularly variable in size and contents, which makes understanding their function in intercellular communication or usage as clinical biomarkers challenging. Researchers supported by the Common Fund program recently studied the contents of different size EVs generated from mouse cancer cells and non-cancer cells to learn more. They used membranes with different sized pores to separate large-, medium-, and small-sized vesicle samples, and an even smaller non-vesicle complexes fraction from different cell types. They found that different sized vesicles carried distinct types of RNA. They also found similarities in the protein content based on the size of the vesicle versus the type of cell it came from. Using special techniques to examine single vesicles they also found that specific surface proteins were only present on EVs of certain sizes.
This study offers a glimpse of the complicated molecular and physical landscape of EVs, but higher resolution and better methods are needed. The work also suggests that by combining vesicle size and content information, it may be possible to know more about their cellular origin. The Extracellular RNA Communication program, now in a second stage, will build upon this knowledge to develop improved approaches to sort, separate, and isolate individual carriers.
Physical and Molecular Landscapes of Mouse Glioma Extracellular Vesicles Define Heterogeneity. Gyuris, A., J. Navarrete-Perea, A. Jo, S. Cristea, S. Zhou, K. Fraser, Z. Wei, A. M. Krichevsky, R. Weissleder, H. Lee, S. P. Gygi and A. Charest (2019). Cell Rep 27(13): 3972-3987 e3976.
Is Music a Universal Language?
Music has been hailed as “the universal language of mankind.” But while scholars acknowledge that people from all around the world make music, the immense variability of songs from different cultures draws into question what exactly about music is “universal.” Are specific behaviors, like dance or courtship, linked to song across cultures? Can musical features in songs like rhythm, melody, or emotional effect predict how a song might be used? NIH Director’s Early Independence Awardee Dr. Samuel Mehr carried out a systematic analysis of vocal music from across the globe to quantitatively evaluate these questions. He and his team built a comprehensive database they termed the Natural History of Song, composed of both texts describing 4,709 song performances from 60 traditionally-living societies and a smaller collection of 118 recorded songs from 86 societies. They analyzed four types of songs drawn from this database: dance, lullaby, healing and love.
Using a unique combination of computational analysis, statistics, social science and humanistic data, Dr. Mehr and his team investigated the different contexts in which songs were performed and the variation in musical content across genres. Music was indeed a part of every culture studied, supporting its universality. Although substantial variation in the complexity of melodies and rhythms existed across cultures, three main factors—formality, arousal (whether the music was lively or calming), and religiosity— captured variation in the performance and use of songs across societies. Further, the researchers found that songs varied more within societies than between them. Music was systematically associated with behavior; each culture’s songs for dance, healing, lullaby and love shared similar properties, and listeners were able to successfully classify songs from foreign cultures by genre.
The researchers acknowledge that biases exist, since songs were characterized and analyzed through the lens of Western scholars and listeners. But by combining a rich dataset of human song with computational and statistical methods that attempt to correct for these biases, the researchers demonstrate a novel way to quantify the features that make music universal. These findings advance our understanding of how we perceive, create, and engage with music, and one day may be leveraged to improve health outcomes in infancy and adulthood.
Reference: Universality and Diversity in Human Song. Mehr SA, Singh M, Knox D, Ketter DM, Pickens-Jones D, Atwood S, Lucas C, Jacoby N, Egner AA, Hopkins EJ, Howard RM, Hartshorne JK, Jennings MV, Simson J, Bainbridge CM, Pinker S, O’Donnell TJ, Krasnow MM, Glowacki L. Science 366, eaax0868 (2019). DOI: 10.1126/science.aax0868
Saying "No" to Pay-As-You-Go?
Health care spending is growing, and multiple efforts have been proposed to curb it. Some suggested solutions focus on changing how insurers pay provider organizations (e.g. hospitals and clinical practices) for their care. A common practice requires insurers to pay a fee for each service provided, a model which can incur exaggerated costs due to a desire for more services, even when the benefit is unclear (fee-for-service model). However, a competing model sets an annual budget for clinical practices for a group of patients, which can promote more preventative care and discourage unnecessary services, lowering spending (Global Payment Model).
Unfortunately, evidence supporting this model is often short-term, mixed, and offers limited insights on health care outcomes. To address this issue, Early Independence Awardee, Dr. Zirui Song conducted a study focused on what could be the most expansive and longest-running private-payer contract of a population-based global payment model.
Dr. Song’s team used insurance claims data from 2006 to 2016 within the Blue Cross Blue Shield of Massachusetts database. The longest-term data is from the first cohort of providers, which joined the plan in 2009. Over 2009 to 2016, average annual spending on claims had slower growth for the first cohort of people in the global payment model-based contract. They saved nearly 12% ($461 per member, per year) on medical claims, compared with control patients, likely enrolled in traditional, fee-for-service plans in northeastern states. Other cohorts with fewer years in the Global payment model had comparable or smaller savings on claims. Patients also received improved quality of care for chronic diseases and conditions (e.g. diabetes and high blood pressure) and experienced fewer emergency room visits than patients in comparable states.
There are some limitations, including the locality and Massachusetts-specific policies, which may hinder how well the study’s findings apply to other locations. However, the expansive and detailed nature of this research is an important step in building evidence for measures that preserve high-quality of care while addressing ballooning health care costs.
Reference: Health Care Spending, Utilization, and Quality 8 Years into Global Payment. Song, Z., Ji, Y., Safran, D. G., & Chernew, M. E.The New England Journal of Medicine, (2019).381, 252-263.
Safety First: Developing Tools and Biomarkers to Prevent Nerve Injury
SPARC2 projects are developing next generation tools and technologies to detect and monitor nerve structure changes in real-time
Bioelectronic medicine, the use of therapeutic devices to modulate electrical activity in nerves and improve organ function, has the potential to treat a wide variety of diseases and conditions, such as heart arrhythmias, gastrointestinal disorders, and type II diabetes. The nerves that connect the brain and spinal cord to organs in the body are composed of long cable-like bundles of fibers called axons, wrapped in a supportive layer of connective tissue that contains blood vessels essential for nerve health and function. As with any therapeutic, safety is enhanced by understanding and reducing potential unintended effects, including tissue damage to stimulated nerves.
A team at SPARC awardee institution Massachusetts General Hospital, led by Dr. Benjamin Vakoc, worked with scientists in the medical device laboratories at the Food and Drug Administration (FDA) to develop a novel approach for predicting and preventing nerve injury caused by electrical stimulation in real time. In order to capture a clear image of tissue damage, they created a custom 3D-printed device to simultaneously stimulate the nerve while also stabilizing it to prevent blurry images caused by breathing and muscle movement. They used optical coherence tomography (OCT), an imaging approach that measures the quantity and direction of light deflected and reflected by tissue, to monitor blood flow and blood vessel size during electrical stimulation of the sciatic nerve. They then compared OCT observations during stimulation with established analyses of nerve function and tissue structure to correlate the changes with nerve injury. This approach points to new real-time biomarkers that could be used to calibrate bioelectronic medicine therapies in order to predict and prevent nerve injury.
Reference: Toward optical coherence tomography angiography-based biomarkers to assess the safety of peripheral nerve electrostimulation. Vasudevan S, Vo J, Shafer B, Nam, Ahhyun S, Vakoc B, Hammer D. J Neural Eng. 2019 Jun.
Don’t Sweat It: Harnessing the Power of Brown Fat to Burn Calories
SPARC1 projects are mapping the innervation of organs and tissues, identifying new targets for future neuromodulation therapies
What if you could burn extra calories without breaking a sweat? It may sound counterintuitive, but a specific type of fat – called brown fat – has the potential to do just that. Brown fat is abundant in infants, where it helps regulate body temperature by converting energy stored in fat and sugar into heat. For decades scientists thought that brown fat didn’t have an active role later in life, but that view has changed in recent years with the discovery of brown fat deposits in adults that are activated by drops in temperature. When faced with cold temperatures, the nervous system sends electrical signals that tell brown fat cells to burn more calories, which helps raise the body’s core temperature to a more comfortable level. If scientists could figure out a way to regulate the intricate network of nerves that send these signals in order to harness brown fat’s calorie-burning potential this knowledge could be applied in a variety of ways – from treatments for health conditions related to energy regulation, such as diabetes, to enhancing the healthy effects of exercise.
To do this, we would need to know more about the locations of the nerves by finding a way to see through brown fat to map the neurons that innervate it. A team at SPARC awardee institution Louisiana State University, led by Dr. Heike Münzberg, used a combination of mouse genetics and fluorescent tracers to light up the neurons. They then made them visible using a recently developed chemical process for “clearing” the intact tissue containing the nerves. This process enables high-resolution imaging and 3D reconstruction of the specific neurons that innervate brown fat, without disturbing their location in the tissue. Improved understanding of brown fat innervation patterns could lead to neuromodulation strategies to precisely control the metabolic activity of brown fat by regulating the nerves’ electrical signals. These new tissue-clearing and circuit-tracing methods are being used to visualize and map innervation of other organs and tissues, bringing us closer to identifying precise targets for neuromodulation therapies that could be used to treat a variety of diseases and conditions.
Reference: Sympathetic innervation of the interscapular brown adipose tissue in mouse. François M, Torres H, Huesing C, Zhang R1, Saurage C, Lee N, Qualls-Creekmore E, Yu S, Morrison CD, Burk D, Berthoud HR, Münzberg H. Ann N Y Acad Sci. 2019 Jun 11.
Mouse Database Guides New Understanding of Skin and Eye Health in Humans
Researchers mined a publicly available database containing data generated and continuously updated by the International Mouse Phenotyping Consortium (IMPC) to identify mouse genes associated with eye and skin abnormalities. The IMPC database is a resource not only for the scientific community, but also for clinicians who may want to find clues from mice on the genetic basis of certain human diseases. Mouse genes often are helpful for identifying and understanding equivalent genes in humans. The NIH Common Fund Knockout Mouse Phenotyping Program (KOMP2) is part of this global effort to develop this database.
There are many skin and eye disorders resulting from the same single gene mutations in both mice and humans. For example, albinism is a disorder affecting both the skin and eyes. While there are some genes linked to some forms of albinism, other cases, such as Oculocutaneous albinism, have no clear genetic cause.
The researchers used the database to search for “knockout” mice with skin, hair, or pigmentation abnormalities. They found 307 different knockout mice with skin abnormalities. Of these, 52 also had eye abnormalities. For 17 of these 52 knockout mice, there was existing literature so the researchers already knew these gene knocks would have eye or skin problems. However, 35 of the 52 knockouts revealed new genes to study with the potential to better understand albinism. These newly identified genes may also point to potential targets for gene or drug therapy in humans.
Moore, B. A., A. M. Flenniken, D. Clary, A. S. Moshiri, L. M. J. Nutter, Z. Berberovic, C. Owen, S. Newbigging, H. Adissu, M. Eskandarian, C. McKerlie, S. Brown, S. Wells, A.-M. Mallon, A. L. Beaudet, M. H. de Angelis, N. Karp, B. Braun, Y. Herault, X. Gao, Y. Obata, P. Flicek, T. Meehan, H. Parkinson, D. Smedley, J. K. Seong, G. Tocchini-Valentini, F. Mammano, S. M. Thomasy, K. C. K. Lloyd, C. J. Murphy, A. Moshiri and C. International Mouse Phenotyping (2019). "Genome-wide screening of mouse knockouts reveals novel genes required for normal integumentary and oculocutaneous structure and function." Scientific Reports 9(1): 11211.
Synthesizing Sugars is No Piece of Cake?
Glycans are sugars that have many important biological and medical applications, such as use in clinical diagnostics and in glycan-based vaccines. However, it is difficult to obtain large enough quantities of specific glycans from nature and current methods of synthesizing glycans in the lab are time consuming and labor intensive. Current synthesis methods require skilled researchers in highly specialized laboratories and can involve as many as 100 steps. Even skilled researchers can have a very hard time making enough glycans for biomedical studies. The Glycoscience Program is developing new tools, techniques, and methods to create large amounts of glycans by simpler methods, which will make the study of glycans more accessible to the biomedical research community.
Glycoscience Program-funded investigator Dr. Geert Jan-Boons and his research team have developed a new “stop and go” approach to glycan synthesis that involves 10 or fewer steps and is designed to mimic natural glycan synthesis in the body. A process of modifying proteins by adding glycans, called “N-glycosylation,” is one of the most diverse and complex types of protein modifications. N-glycosylation is involved in many biological processes, such as neuron development, fertilization, immune regulation, and in many disease processes. This new “stop and go” strategy allows for synthesis of useful amounts of a variety of complex N-glycans without the need for special synthesis skills, providing glycans for biomedical research.
Another investigator with the Glycoscience program, Dr. Peng George Wang and his research team, developed a fully automated system to efficiently synthesize glycans using enzymatic reactions, a temperature dependent polymer, and repurposing a commercially available peptide synthesizer. Several important glycans, such as blood group antigens (i.e. the sugars on the surface of blood cells that designate A, B, and O blood types), were synthesized using this system. These experiments illustrate the important ways in which the Glycoscience Program is simplifying glycan synthesis while expanding the diversity of glycans available for biomedical research.
Machine-Driven Enzymatic Oligosaccharide Synthesis by Using a Peptide Synthesizer. Zhang J, Chen C, Gadi MR, Gibbons C, Guo Y, Cao X, Edmunds G, Wang S, Liu D, Yu J, Wen L, and Wang PG. 2018. Angew Chem 130: 16880-16884.
Streamlining the chemoenzymatic synthesis of complex N-glycans by a stop and go strategy. Liu L, Prudden AR, Capicciotti CJ, Bosman GP, Yang JY, Chapla DG, Moreman KW, and Boons GJ. 2018. Nature Chemistry: DOI:10.1038/s41557-018-0188-3.
Modeling Mutations to Better Predict Breast Cancer Outcomes
Although the disease breast cancer has one general name, the tumors that define it often contain different genetic mutations. In fact, a single tumor can have groups of cells with different mutations that arise naturally as a tumor grows or that occur after exposure to cancer treatments. This is important because certain mutations allow cancer cells to resist therapies and make the cancer more likely to recur. Dr. Christina Curtis, an NIH Director’s Pioneer Awardee, published two papers in Nature Communications and Nature where she applies computer modeling to genetic data from tumors and clinical follow-up data from patients to get a better understanding of the extent of genetic variability in breast cancer tumors before and after treatment.
In the first study, Dr. Curtis used computer models to investigate differences in genetic mutations between a tumor sample taken at diagnosis to one taken after surgery. Patients in this study had untreated tumors prior to surgery or received pre-surgery chemotherapy. Dr. Curtis’s computer modeling showed that genetic differences in breast cancer tumors may be present even before treatment, and in greater numbers than expected. Their data led them to suggest at least two areas of the same tumor should be sampled to accurately identify treatment-induced mutations. They also used the data to find evolutionary factors associated with tumor treatment-resistance, which could lead to better predictions of tumor behavior.
In the second report, Dr. Curtis and colleagues obtained data from over 3,000 breast cancer patients and used findings from her past research to group the cancer patients based on the molecular make-up of their tumors, including their genetic make-up. In doing this, she created the largest breast cancer cohort with both molecular characteristics and long-term follow up data to date. From this cohort, Dr. Curtis’s team discovered four groups of patient tumors that were prone to recurring later in life, up to 20 years after diagnosis. Collectively, these recurrent tumors made up about 26% of the tumors assessed. On the other end of the spectrum, they uncovered a group of breast cancers that rarely recur after five years. These molecular subtypes may help to improve predictions of late stage relapses beyond what is generally possible today, and someday guide treatment recommendations.
Clonal replacement and heterogeneity in breast tumors treated with neoadjuvant HER2-targeted therapy. Caswell-Jin, J. L., McNamara, K., Reiter, J. G., Sun, R., Hu, Z., Ma, Z., Ding, J., Suarez, C. J., Tilk, S., Raghavendra, A., Forte, V., Chin, S-F., Bardwell, H., Provenzano, E., Caldas, C., Lang, J., West, R., Tripathy, D., Press, M. F., Curtis, C., Nature communications (2019) 565(7739), 361.
Dynamics of breast-cancer relapse reveal late-recurring ER-positive genomic subgroups. Rueda, O. D., Sammut, S-J., Seoane, J. A., Suet-Feung, C., Caswell-Jin, J. L., Callari, M., Batra, R., Pereira, B., Bruna, A., Ali, H. R., Provenzano, E., Liu, B., Parisien, M., Gillett, C., McKinney, S., Green, A. R., Murphy, L., Purushotham, A., Ellis, I. O., Pharoah, P. D., Rueda, C., Aparicio, S., Caldas, C., & Curtis, C. Nature (2019).
In the News:
- New Study Says Breast Cancer is 11 Different Diseases, Allowing Researchers to Predict Relapse
- Molecular Data Can Predict Breast Cancer Recurrence
- Why Does Breast Cancer Recur? New Study Finds Clues
Rejection Detection (of Transplants)
Successful organ transplants are important to the quality of life of patients with end-stage organ failure. Early detection of acute transplant rejection can increase a patient’s chances for survival, by allowing clinicians to intervene and use anti-rejection drugs to save the graft or organ. Unfortunately, current detection approaches, including tissue biopsies, can involve additional surgery, result in sampling errors, or can lead to additional health issues and disease.
The early stages of organ or graft rejection (when the host’s immune cells attack the new transplant) is linked to increases in some biomolecules. One that has been correlated with this stage is Granzyme B, which acts a signal for cell death. New Innovator Awardee Dr. Gabriel Kwong has developed a groundbreaking nanosensor that detects the early transplant rejection marker, Granzyme B, and activates a fluorescent indicator that is passed in the patient’s urine—no additional surgery required.
Dr. Kwong and his team injected the nanosensor into rodent skin graft models and found the sensors could successfully detect early graft failure. Although rigorous testing is needed before it is ready for use in humans, future developments of this technology could allow for better, and less invasive, detection of transplantation failures to give doctors a versatile tool to manage patient health.
Reference: Non-invasive early detection of acute transplant rejection via nanosensors of granzyme B activity(note: full text may require institutional access). Mac, Q. D., Matthews, D. V., Kahla, J. A., Stoffers, C. M., Delmas, O. M., Holt, A.H., Adams, B. A., & Kwong, G. A. Nature Biomedical Engineering (2019). https://doi.org/10.1038/s41551-019-0358-7
In the News:
Urine Test Detects Organ Transplant Rejection, Could Replace Needle Biopsies
Georgia Institute of Technology
Antiseptic Bathing Reduces Infections in Hospital Patients
Hospital associated infections result in billions of dollars of healthcare costs and thousands of deaths every year. The Active Bathing to Eliminate Infection (ABATE) Trial, led by Dr. Susan Huang from the University of California, Irvine, collected real world data on bathing hospital patients with an antiseptic soap, chlorhexidine, during inpatient hospital stays. A previous study from Dr. Huang and colleagues showed that using this type of bathing as routine care in the intensive care unit (ICU) reduced bloodstream infections by up to 44 percent. Given those exciting results, the ABATE study was designed to test whether bathing with chlorhexidine as well as targeted use of a nasal antibiotic, mupirocin, would also reduce infections in non-ICU patients.
The ABATE study was conducted in 53 hospitals and compared routine bathing to bathing with chlorhexidine in over 330,000 non-ICU patients. In this large and diverse population of patients, there was not a statistically significant difference in the number of infections that occurred between the control and antiseptic bathing, suggesting that switching to this type of bathing as routine practice for all patients would not be an effective method for reducing infections. However, when considering only patients with a medical device, such as a central venous catheter or a lumbar drain, there was a reduction in bloodstream infections of over 30 percent when patients were assigned to the antiseptic bathing. Therefore, this bathing practice should be valuable for this higher risk subset of hospital patients. One of the health care systems in which this study took place already adopted this form of bathing for these patients because of the results from the ABATE Trial.
Reference: Chlorhexidine versus routine bathing to prevent multidrug-resistant organisms and all-cause bloodstream infections in general medical and surgical units (ABATE Infection trial): a cluster-randomised trial. Huang SS, Septimus E, Kleinman K, Moody J, Hickok J, Heim L, Gombosev A, Avery TR, Haffenreffer K, Shimelman L, Hayden MK, Weinstein RA, Spencer-Smith C, Kaganov RE, Murphy MV, Forehand T, Lankiewicz J, Coady MH, Portillo L, Sarup-Patel J, Jernigan JA, Perlin JB, Platt R, ABATE Infection trial team. Lancet. 2019 Mar 4. doi: 10.1016/S0140-6736(18)32593-5.
What's the Matter Bladder?
Overactive bladder is a condition that affects millions of people and causes a frequent need to urinate, incontinence, and an increase in bladder voiding. A common treatment uses low levels of electricity to stimulate nerves controlling the bladder. Unfortunately, it’s not precise and can lead to off-target effects and pain.awardee Dr. Aaron Mickle developed an innovative approach to this problem by creating a miniature implanted device that can sense and control bladder function in rats. This self-adjusting coordination of devices, that manipulate nerves to control organs, is called a closed-loop system.
Instead of activating nerves using electricity, Dr. Mickle and his team used a technique called optogenetics where genetically modified rat nerve cells could be activated using light. In rats, Mickle’s team inserted a stretch sensor that measured changes in bladder expansion over time. The sensor was connected to LEDs. Both were connected by wires to a flexible base-station device implanted in the abdomen. The bladder-stretch sensor communicated data to the base station, which wirelessly transmitted this information to an external device that recorded and monitored bladder function. Rats received the molecule cyclophosamide, which leads to frequent bladder emptying. When the external device detected this abnormal bladder function (i.e. signs of overactive bladder), it transmitted a wireless signal causing light-driven inhibition of nerves affecting bladder emptying—preventing abnormal frequency of urination.
Although the animal model of overactive bladder shows promise for this technology, questions remain about whether this approach could be used in humans or to treat other diseases. Additionally, the body’s long-term response to the stretchable sensor is unknown and there are other concerns about possible tissue damage or unintended adhesion to the tissue that affect the device’s function. However, if it ultimately proves fruitful, this work could correct organ dysfunction and manage pain.
Reference:. Mickle, A. D., Won, S. M., Noh, K. N., Yoon, J., Meacham, K. W., Xue, Y., Mcllvried, A. L., Copits, B. A., Samineni, V. K., Crawford, K. E., Kim, D. H., Srivastava, P., Kim, B. H., Min, S., Shiuan, Y., Yun, Y., Payne, M. A., Zhang, J., Jang, H., Li, Y., Lai, H. H., Huang, Y., Park, S., Gereau IV, R. W., & Rogers, J. A. Nature (2019) 565(7739), 361.
In the News:
Faculty Support Career Development of Their Trainees
Faculty mentors are critical to the research training of graduate students and postdoctoral scientists, but there are little data about how faculty members value the time and effort their trainees spend on career development. To address this gap, seven NIH Broadening Experiences in Scientific Training (BEST) institutions conducted surveys of over 700 faculty at their institutions on faculty perceptions of professional and career development for trainees. BEST institutions are conscious that having faculty support activities for trainees is essential and learning more about what faculty believe and value will inform their program development.
Results from these surveys suggest that faculty are generally aware that a majority of biomedical trainees will ultimately pursue career paths outside of academia. In general, they also report that while they actively mentor trainees about non-academic career opportunities, the majority do not believe they have a good understanding of skills needed in non-academic career opportunities or the non-academic contacts to help their mentees. Faculty also responded that time spent on training for non-academic careers, like in BEST activities, was acceptable to them and valuable to both graduate and postdoctoral trainees. Interestingly, while the majority of faculty stated they talk with both graduate and postdoctoral scientists about a myriad of professional non-academic careers, most faculty were less sure that their fellow colleagues provided the same kind of discussion, resources, and opportunities. Overall, these findings support the need for BEST and BEST-like programs to help trainees explore expanded career opportunities and support faculty mentors that are not fully prepared to offer this training on their own.
Faculty perceptions and knowledge of career development of trainees in biomedical science: what do we (think we) know? Watts SW et al. PLoS One. 2019 Jan 30. doi.org/10.1371/journal.pone.0210189
Stem Cell-Based Treatment Used to Prevent Blindness In Animal Models of Retinal Degeneration
Age-related macular degeneration (AMD) is the most common cause of blindness among the elderly. With limited treatment options for AMD patients, scientists turned to regenerative medicine approaches, pursuing an induced pluripotent stem cell (iPSC) based therapy for AMD. IPSCs are cells taken from patient tissues and coaxed into a stem cell-like state where they can be become any cell type in the body. In a study led by Dr. Kapil Bharti, a Regenerative Medicine Program-funded investigator, dying retinal pigment epithelial (RPE) cells in pigs and rats with retinal deterioration were replaced with human iPSC-derived RPE cells. The replacement cells helped nurture photoreceptors, the light-sensing cells in the retina. Both healthy RPE and photoreceptor cells are necessary to maintain vision. With both cell types now in place, the investigators observed that the iPSC-based therapy successfully prevented blindness in the animals. The findings from this study will inform a first-in-human clinical trial to treat AMD.
Watch Dr. Bharti explain his research: https://youtu.be/k6DTj597Gv8
Image: This is a scanning electron microscope image of an RPE monolayer growing on top of a biodegradable scaffold (blue, left side of image). The polarity of the RPE cells is clearly visible (brown, bottom of cells in middle of image; green, top of cells on right side of image).
Clinical-grade stem cell–derived retinal pigment epithelium patch rescues retinal degeneration in rodents and pigs. Sharma R, Khristov V, Rising A, Jha BS, Dejene R, Hotaling N, Li Y, Stoddard J, Stankewicz C, Wan Q, Zhang C, Campos MM, Miyagishima KJ, McGaughey D, Vilasmil R, Mattapallil M, Stanzel B, Qian H, Wong W, Chase L, Charles S, McGill T, Miller S, Maminishikis A, Amaral J, Bharti K. Science Translational Medicine. January 16, 2019 (Note: full text of the article may require institutional access)
In the news:
- NIH researchers rescue photoreceptors, prevent blindness in animal models of retinal degeneration-NEI Press Release
- Macular degeneration trial will be first human test of Nobel-winning stem cell technique-STAT
- Moving Closer to a Stem Cell-Based Treatment for AMD- NIH Director's Blog
This page last reviewed on January 22, 2020