What’s New With Our Students?
AWARDS AND FELLOWSHIPS:
Alex Lohman – 2014 Michael J. Peach Outstanding Graduate Student Award
Chelsi Snow – 2014 Jill E. Hungerford Prize in Biomedical Sciences
Madison Stellfox – 2014 GBS Student Leadership Award
2014 Outstanding Graduate Students Awards
- Biochemistry and Molecular Genetics - Chelsi Snow (Dr. Bryce Paschal, Mentor)
- Biomedical Engineering – Karen Ryall (Dr. Jeff Saucerman, Mentor)
- Biophysics – Aravinda Kuntimaddi (Dr. John Bushweller, Mentor)
- Cell and Developmental Biology – Jianyi Lee (Dr. Xiaowei Lu, Mentor)
- Microbiology, Immunology, & Cancer Biology – Christine Coquery (Dr. Loren Erickson, Mentor)
- Molecular and Cellular Basis of Disease - Heather Perry (Dr. Coleen McNamara, Mentor)
- Neuroscience – Benjamin Thiede (Dr. Jeff Corwin, Mentor)
- Pharmacology – James Eaton (Dr. Thurl Harris, Mentor)
- Molecular Physiology & Biological Physics – Alex Lohman (Dr. Brant Isakson, Mentor)
2014 Poster Prize Awards
- 1st Place – James Cronk & Xinyuan Cui
- 3rd Place – Emily Moser
BIMS students, Karen A. Ryall, Brandon M. Kenwood and Kristopher H. Chain, are among authors in a newly published article in the Journal of Biological Chemistry.
UVA Develops New Tool to Check Cells’ ‘Batteries’
By Illuminating Mitochondria, Researchers Shed Light on Disease, Human Health
CHARLOTTESVILLE, Va., April 3, 2014 – Under the microscope, they glow like streetlights, forming tidy rows that follow the striations of muscle tissue. They are mitochondria, the powerhouses of cells, and researchers at the University of Virginia School of Medicine have created a method to illuminate and understand them in living creatures like never before. Not only can the researchers make the mitochondria fluoresce, to glow for the microscope, but they can discern from that fluorescence the mitochondria’s age, their health, even their stress level. And ultimately that glow, in its soft reds and greens, will shed light on human health and a massive array of illnesses, from diabetes to Parkinson’s disease to cancer.
“Mitochondrial health is important for physiology and disease. That is well known. However, the whole field of mitochondrial health is largely unexplored, in large part because of the lack of useful tools. This has hindered the understanding of the importance of mitochondria in disease development,” said UVA researcher Zhen Yan, PhD, of the UVA Cardiovascular Research Center. “With this study we have, for the first time, shown that we can use a reporter gene to measure mitochondrial health robustly in vivo. We believe this tool will allow us to get into the field of mitochondrial biology like never before.”
“Before, we could see the mitochondria under an electron microscope. That showed us only what they looked like,” Yan said. “Now we can measure the health of millions of mitochondria at the click of a button.”
Health and Stress
Yan and his team based the new tool on a reporter gene, a type of gene used in scientific research to determine the activity and function of other genes. The reporter gene produces a protein that glows green when newly made; the protein then transitions to red as it ages. By giving the reporter gene specific targeting directions, the UVA researchers were able to instruct the protein to enter the mitochondria, setting them aglow. “So now we have fluorescent mitochondria, which are fluorescent green initially and then, as the mitochondria age or become oxidized, they transition to red, so that we can assess the oxidation status,” said Rhianna Laker, PhD, a postdoctoral fellow in Yan’s lab and the lead author of a new paper detailing the work.
The researchers have put their tool to the test in flies, worms and mice. They found that mice fed a high-fat diet had more red mitochondria, meaning the mitochondria were stressed or oxidized, while mice that exercised had more green mitochondria, Laker said. That finding speaks both to the importance of exercise and to the potential diagnostic power of the new tool, dubbed the MitoTimer.
The Big Picture
Taking advantage of the wide-ranging expertise at the School of Medicine, Yan’s lab collaborated with Jeff Saucerman, PhD, of the Department of Biomedical Engineering, to take the work to the next level. Saucerman’s team has developed a computer program that can analyze the degree of mitochondrial fluorescence to assess both individual mitochondria and the overall ratio of red to green in a particular area. That ratio speaks to the health of the cells. “The mitochondria are both the powerhouse of the cell and a sensor of metabolic state and stress,” Yan said.
The findings have been published online in the Journal of Biological Chemistry and will appear in a forthcoming print edition. The article was authored by Rhianna C. Laker, Peng Xu, Karen A. Ryall, Alyson Sujkowski, Brandon M. Kenwood, Kristopher H. Chain, Mei Zhang, Mary A. Royal, Kyle L. Hoehn, Monica Dirscoll, Paul N. Adler, Robert J. Wessells, Jeff Saucerman and Zhen Yan.
Congratulations to UVa BIMS Graduate Student, Lindsey Brinton winner of the People’s Choice Award for competing in the international thesis challenge – Universitas 21 (U21) Three Minute Thesis Online Competition 2013! Thank you to all who voted!!!
Way to Go Lindsey!!!
Zegbeh Kpadeh, a Microbiology Ph.D candidate in the lab of Paul Hoffman has received a Robert D. Watkins Fellowship Grant from the American Society for Microbiology. Deciphering the Bifunctional Role of Oxidoreductase DsbA2 in Legionella pneumophila. Legionella pneumohila (Lpn’ disease when aerolized bacteria infect human alveolar macrophage. Lpn displays a dimorphic developmental cycle in which the vegetative replicating bacilli differentiate into metabolically dormant cyst-like planktonic forms, which are known to be resilient and highly infectious. Disulfide bond (DSB) formation is essential for the folding, activity, and stability of many proteins exported from the cytoplasm to the periplasm. The Dot/Icm type IVb secretion system (T4SS) is essential for virulence and mediates delivery of multiple effector proteins into the host cytoplasm. The proper assembly and function of the Dot/Icm T4SS is dependent on correct DSB formation catalyazed by a novel and essential periplasmic DSB oxidoreductase DsbA2 and not by DsbA1, a second nonessential DSB oxidoreductase. This investigation examines the activities and function of a disulfide bond oxidoreductase, DsbA2, which exists as a bifunctional homodimer with both oxidoreductase and protein disulfide isomerase activity. By gaining a better understanding of the activities and function of this protein in Lpn, we hope to gain new insights into the pathogenic processes utilized by Lpn during infection.
Previous Education: BS Biology, Morgan State University(BIMS 8/2013)
Christine Coquery, an Immunonolgy Ph.D candidate in the lab of Loren Erickson has received a Ruth L. Kirschstein National Research Service Award. The Role of B Cell Maturation Antigen in Controlling Tolerance.The establishment of long-lived plasma cells (PC) is a hallmark of the adaptive immune response and is critical for host protection against pathogens. In autoimmune diseases, such as systemic lupus erythematosus (SLE), this process is disrupted to generate self-reactive long-lived PCs (LL-PCs) that produce pathogenic auto-antibodies. This project tests the hypothesis that B Cell Maturation Antigen (BCMA), which is not only present on B lymphocytes but also on T follicular helper (TFH) cells, in the context of an inflammatory environment, that help to drive proliferation and differentiation of PCs, is 1) a critical regulator of TFH cells in autoimmunity and 2) signaling through BCMA on TFH cells can modulate their cytokine production, proliferation, and survival.The overall goal of this project is to define the qualities of TFH cells in autoimmune-prone mice in the presence and absence of BCMA, and to determine their role in the development of long-lived PCs in order to understand the role of BCMA in mediating tolerance.
Previous Education: MS Biomedical Studies, Baylor University; BS Human Biology, University of California San Diego(BIMS 8/2013)
Steven Griffith, a Biochemistry and Molecular Genetics Ph.D. candidate in the lab of Gary Owens has received a fellowship from the Mid-Atlantic Affiliate of the American Heart Association. The role of H3K4me2 in Smooth Muscle Cell Phenotypic Modulation. A fundamental question in developmental biology is understanding how multipotent embryonic stem cells (ESCs) that share the same DNA sequence can acquire unique characteristics that enable a large variety of functions. One theory postulates that, while genetically identical, ESCs within the blastocyst are epigenetically distinct and thus are capable of responding rapidly to extracellular and environmental cues that cause differential regulation of gene expression and allow the cells to differentiate into various lineages. This, in turn, results in the initial cell heterogeneity. Once this heterogeneous cell population is established, cellular determination is then extended through both intrinsic and extrinsic mechanisms arising from the availability of metabolites, environmental cues, matrix components, cellular location, and morphogens. These factors gradually program cells down a specific lineage path, resulting in the generation of committed, distinct cell populations and tissues that maintain their specialized characteristics through subsequent cell divisions. The mechanism through which cells retain this ”lineage memory” is thought to arise through epigenetic changes, including histone modifications, DNA methylation, and ATP-dependent chromatin remodeling. This project tests the hypothesis that smooth muscle cells (SMCs) undergo reversible phenotypic modulation during vascular repair in vivo and that this process is dependent on an epigenetic lineage memory control process involving stable histone modifications of SMC specific gene loci. My work will definitively determine whether or not Smooth Muscle Cells are capable of undergoing phenotypic modulation in response to vascular injury, a process long suspected to be a major player in a large array of vascular diseases (such as atherosclerosis) as well as determine if removal of a single epigenetic mark at specific gene loci in an individual cell type results in loss of cellular memory in vivo.
Previous Education: BS Biochemistry, Schreiner University - Kerrville, TX(BIMS 8/2013)
Ryan Llewellyn, a Microbiology Ph.D. candidate in the lab of Amy Bouton has received Ruth L. Kirschstein National Research Service Award for Individual Predoctoral Fellows from the National Institutes of Health. The Role of FAK in Regulating Macrophage Migration and Function in Mammary Tumors. Our research explores the fundamental contribution of Focal Adhesion Kinase (FAK) to macrophage migration and function, which may contribute to regulation of breast tumor progression. Mice with FAK conditionally deleted in myeloid lineage cells (FAKΔmyeloid) were crossed with mice that develop spontaneous breast carcinomas due to expression of the MMTV-PyMT transgene. FAKΔmyeloid MMTV-PyMT mice showed significantly enhanced primary tumor outgrowth compared to wildtype (WT) littermate MMTV-PyMT animals. Based on data generated from our lab, we hypothesize that monocytes upregulate FAK and differentiation into mature macrophages once they have extravasated out of the tumor vasculature and enter the tumor parenchyma. This, in turn, could promote increased movement of these cells within the tumor microenvironment, which may help to control tumor size/outgrowth through functions that ultimately mediate anti-tumor effects. To test this hypothesis, we are first determining if FAK expression in macrophages regulates the migration or localization of these cells in the tumor. In parallel, we are assessing whether FAK expression regulates macrophage functionality in the tumor. This research will provide new insights into the mechanisms driving breast tumor growth and identify new considerations for treating breast cancer patients.
Previous Education: B.A. in Biology, University of Virginia(BIMS 8/2013)
What’s New With Our Faculty?
Fluorescence micrograph of primary human neutrophils infected with the bacterium Neisseria gonorrhoeae, showing that some bacteria remain viable intracellularly. Internal viable bacteria appear green, internal nonviable bacteria appear red, external viable bacteria appear turquoise (blue and green), and external nonviable bacteria appear magenta (blue and red). Neutrophil nuclei also fluoresce red. N. gonorrhoeae can survive within neutrophils by residing in immature phagosomes that do not fuse with primary (azurophilic) granules. For further details see Brittany Johnson and Alison Criss, 2013. Cellular Microbiology 15: 1304-1321.
Two modes of binding of DinI to RecA filament provide new insights into the regulation of the SOS response by the DinI protein.
Wladek Minor, Ph. D., Department of Molecular Physiology and Biological Physics
The TetR family transcriptional regulator TM1030 from the hyperthermophile Thermotoga maritima is shown in a complex with DNA. The crystals in the background were grown in temperatures ranging from 4 – 50°C. Crystallization at elevated temperatures is uncommon, even for proteins from mesophilic and thermophilic organisms. The series of structures reported in this manuscript show that such proteins can be stable at elevated temperatures and that the quality of the crystallographic data and subsequent refined structures do not depend on the crystallization conditions.