Richard J. Albertini, M.D., Ph.D. (Professor, Department of Pathology)

• NIH Study Section - ALTX, Panel 2 (Genetic, Immuno and Neuro Tox.), 1996-1997;
• Chair, International Symposium on "Evaluation of Butadiene, Isoprene and Chloroprene Health Risks", September 12-14, 2000;
• Peer Review Panel:  NTP SAN Trimer Testing Protocol - Childhood Cancer Cluster, Toms River, NJ, 2000-present

The major research interests in the Genetic Toxicology Laboratory are the causes and consequences of gene mutations in humans.  As these events are directly related at the molecular level to the causes of cancer and inherited genetic disorders, the applications of this research have been in the areas of preventive medicine and environmental health.  Dr. Albertini developed the assay for HPRT mutations arising in vivo in human T-lymphocytes over two decades ago.  This assay is now the most commonly used worldwide for mutagenicity monitoring of exposed populations.  The Genetic Toxicology Laboratory has remained at the forefront in characterizing these mutations by describing molecular mutational spectra for background and environmentally induced alterations in this gene.  There is now an international database for these spectra.  The laboratory has been and remains involved in human monitoring with a broadening of focus to molecular epidemiological studies in general.  In recent years, it has become apparent that HPRT mutations in vivo can serve as probes for fundamental cellular and mutational processes.  This requires molecular analyses of the T-cell receptor (TCR) genes, as well as the HPRT mutations in mutant cells.  Laboratory studies in this direction have led to

1. the recognition of V(D)J mediated deletions in HPRT that mimic analogous changes in cancer relevant genomic regions,
2. an appreciation of the role of cell proliferation in mutagenesis, and
3. the discovery of clonally restricted genomic instability in normal T-cell populations. 

Current research is ongoing in each of these areas.  Most recently, the laboratory has adapted all methods, including molecular characterizations, to the mouse model to allow more in-depth analyses of mechanisms using controlled mutagen exposures and/or transgenic animals.  The role of selection in increasing HPRT mutant T-cell and germ cell populations in the laboratory animals is also being investigated by Dr. Albertini - the latter at the FDA's National Center for Toxicological Research.

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Marcus Bosenberg, M.D., Ph.D. (Assistant Professor, Department of Pathology)

• Pathology Leader, Skin Organ Site, Mouse Models of Human Cancer Consortium, National Cancer Institute (2000-present)
• Chair, 18th Annual Vermont Cancer Center Symposium, "Translational Cancer Research", October 2 - 3, 2003

Our laboratory is interested in understanding the process of tumor metastasis. The clinical importance of metastasis is unquestioned, as most of the mortality associated with cancer is the result of disseminated disease. Despite its importance, the current understanding of the complex process of metastasis is limited. Much of our work involves malignant melanoma, a metastatic and frequently lethal form skin cancer that arises from the pigment-producing cells of the skin. We are interested in several aspects of melanoma biology, including identification of the genetic changes responsible for melanoma formation/progression, characterization of candidate melanoma tumor suppressors and oncogenes, and developing improved mouse models melanoma. Several of the mouse models incorporate the effects of ultraviolet radiation, a known environmental risk factor for the development of melanoma.

Rudolph KL, Millard M, Bosenberg MW, DePinho RA. Telomere dysfunction and evolution of intestinal carcinoma in mice and humans. Nat Genet 2001;28:155-9.

Krop IE, Sgroi D, Porter, DA, Lunetta KL, LeVangie R, Seth P, Kaelin CM, Rhei E, Bosenberg MW, Schnitt S, Marks JR, Pagon Z, Belina D, Razumovic J, and Polyak K. HIN-1, a candidate breast tumor suppressor gene. Proc Natl Acad Sci USA 2001;98:9786-9801

Yantiss RK, Bosenberg MW, Antonioli DA, Odze RD. Utility of MMP-1, p53, E-cadherin, and collagen IV immunohistochemical stains in the differential diagnosis of adenomas with misplaced epithelium versus adenomas with invasive adenocarcinoma. Am J Surg Pathol 2002;26:206-215.

You MJ, Castrillon DH, Bastian BC, O'Hagan RC, Bosenberg MW, Parsons R, Chin L, DePinho RA. Genetic analysis of Pten and Ink4a/Arf interactions in the suppression of tumorigenesis in mice. Proc Natl Acad Sci USA 2002;99:1455-1460.

Kannan K, Sharpless NE, Xu J, O'Hagan R, Bosenberg MW, and Chin L. components of the Rb pathway are critical targets of UV mutagenesis in a murine melanoma model. Proc Natl Acad Sci USA 2003;100:1221-1225.

Sharpless NE, Kannan K, Xu J, Bosenberg MW, DePinho RA, and Chin. Both products of the mouse Ink4a/Arf locus suppress melanoma formation in vivo. Oncogene 2003.

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Ralph C. Budd, M.D., Ph.D. (Professor, Department of Medicine)

• Fogarty International Fellow (Institute of Biochemistry, University of Lausanne, Switzerland; 1998-1999;
• NIH (NIAD, Allergy and Clinical Immunology Subcommittee of the Allergy, Immunology, and Transplantation Research Committee (Chair, 1997-1999).

For information about Dr. Budd's research, visit http://www.uvm.edu/~rbudd

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• J. Walter Juckett Scholar, 2001-2003
  
• Editor, Crystallographic Methods and protocols, "Methods in Molecular Biology", Humana Press, 2003.

Another focus of my laboratory is to decipher the mechanism of the mammalian polyadenylation machinery.  The polyadenylation machinery is a complex composed of five multimeric proteins and messenger RNA.  The complete protein complex can be reconstituted in vivo and has been shown to cleave and polyadenylate messenger RNA bearing the polyadenylation sequence.  We have solved the structure of one of the factors, poly(A) polymerase, and are pursuing the crystal structure determination of protein-RNA complexes of the mammalian polyadenylation machinery in collaboration with Drs. Walter Keller (Biozentrum, Basel, Switzerland), Elmar Wahle (Univ. of Halle, Germany), and Greg Gilmartin (MMG, UVM).  We are also pursuing the crystal structure determination of adenosine deaminases that act on RNA.  These enzymes catalyze the deamination of adenosine to inosine.  A to I editing can have a profound effect on the newly synthesized protein.  Editing of the glutamate-gated cation channel RNA results in drastic changes in the flux of calcium into the neurons. 

Garman, E. F. and Doublié, S. Cryocooling of Macromolecular Crystals: Optimization Methods Methods in Enzymology in press.

Martin, G., Keller, W., and Doublié, S. (2000) Crystal structure of mammalian poly(A) polymerase in complex with an analog of ATP. EMBO J. 19: 4193-4203.

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• 1993-1997 NIH Physician Scientist Award
• 1997-1999 LCCRO J.Walter Juckett Scholar Award
• 1997-1999 Leukemia Society of America Translational Research Scholar
• 1998-2003 NCI Howard Temin Award
• 1998-present Member of the Society of Pediatric Research
• 1999-2002 Leukemia and Lymphoma Society Translational Research Scholar
• 2000 Exemplary Scholar, University of Vermont
• 2000 Co - chair, 16th Annual VCC Research Symposium
• 2000-present Presidents Task Force on Environmental and Safety Risks to Children
• 2000-present Consultant: "Longitudinal Cohort Study of the Environmental Effects on Child Health and Development"
• 2002-present Recipient Burroughs Wellcome Fund Clinical Scientist Award in Translational Research
• 2002-present Leukemia and Lymphoma Society Translational Research Scholar

The major interest of research in this laboratory centers around the mechanisms and clinical relevance of somatic mutations in children.  A T-cell cloning assay is utilized for determining the frequency of somatic mutations at the hprt locus in healthy children and children with various diseases (i.e., cancer, autoimmune diseases) and genotoxic exposures, from early fetal development to adolescent.  One study examines the genotoxic effects of maternal cigarette smoking in healthy term and pre-term infants, using the biomonitoring system.  A major focus of work now centers on investigating the genotoxic effects of chemotherapeutic treatment of pediatric malignancies, especially the effects of radiation, alkylating and topoisomerase treatments.  These translational research studies allow for direct basic scientific investigations at the molecular level of clinically important genotoxic exposures with significant secondary effects. 

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Christopher Francklyn, Ph.D. (Associate Professor, Department of Biochemistry)

Four different families of protein kinases phosphorylate eIF-2 as part of eukaryotic stress responses: the heme regulated kinase (HRI), the double stranded RNA-induced PKR kinase; the endoplasmic reticulum resident  PERK kinase induced by ER-stress; and finally, the GCN2 kinase.  The multidomain architecture of these kinases allows responses to a broad range of environmental stimuli, including starvation, heat shock, viral infection, and endoplasmic reticulum stress.  GCN2 is responsible for integrating nutritional stresses, particularly starvation responses associated with amino acid, glucose, and purine starvation.  The three critical functional domains of GCN2 include a protein kinase domain closely related to other eIF2a kinases, a tRNA synthethase-like domain, and a C-terminal ribosome association domain.  The tRNA synthetase-like domain is 19% identical to eukaryotic histidyl-tRNA synthetases, and we have used the homology between HisRS and GCN2 to make predictions about GCN2 residues required for maintaining the dimeric structure and transducing signals associated with tRNA binding to the kinase domain.  GCN2 is also found in metazoans where, in addition to amino acid limitation, it is apparently involved in the regulation of stress responses important for neuronal tissue.  Notably, GCN2 is required for early development in Drosophila, and GCN2 is highly expressed in the mouse brain.  To explore the structure and function of GCN2, we will build on our modeling work with current major labs in the field, and move on more extensive structural studies using nuclear magnetic resonance and x-ray crystallography.

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Naomi K. Fukagawa, M.D., Ph.D. (Professor, Department of Medicine)

• Chair, American Society for Clinical Nutrition Internship Program, 1998-2000;
• Chair, American Society for Clinical Nutrition, Annual Meeting, 2003;
• Chairperson, Board of Medical Consultants for the PDR Family Guide to Natural Medicine and Healing, Medical Economics, Inc., Montvale, NJ

Dr. Fukagawa is the Acting Director of the Gerontology Unit and is interested in the broad areas of nutrition, aging and protein/amino acid metabolism.

Areas of research include: 

1. Studies in human volunteers examining sulfur amino acid metabolism (methionine, cysteine, homocysteine) and its relationship to aging and cardiovascular disease;
2. Studies in human volunteers examining the utility of stable isotope probes to determine an individual’s glutathione status; 
3.   The impact of aging and hyperglycemia on oxidative damage to mitochondrial DNA including gene expression and deletions and their relationships to diabetes mellitus and cardiovascular disease; 
4.   Effects of oxidative stress and aging on redox-sensitive transcription factors, nuclear factor kappa B and activator protein 1, and related genes such as gamma-glutamylcysteine synthetase and inducible nitric oxide synthase. Techniques utilized include metabolic studies in human volunteers, tissue culture, cell and molecular approaches to assess DNA damage and gene expression, HPLC, biochemical assays, human tissue biopsies and mass spectrometric analysis of stable-isotopically labeled compounds. 

A top priority is the facilitation of the translation of  basic research to in vivo studies in humans.

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Alan K. Howe, Ph.D. (Assistant Professor, Department of Pharmacology)

• Member, Molecular Signaling 1 Study Section, American Heart Association (2005-Present)
• Co-Chair (c/Dr. R. Hovey), 19th Annual Vermont Cancer Center Symposium, “The Course of Cancer: From Transformation to Treatment”, October 7 & 8, 2004
• Recipient, Howard Temin Career Award, National Cancer Institute, 2001-Present

Our laboratory is interested in the signaling cascades that regulate cytoskeletal dynamics and cell migration. Specifically, we study the cAMP-dependent protein kinase (or PKA), how it is regulated by cell adhesion to extracellular matrix, and how it contributes to regulation of the actin cytoskeleton. The laboratory uses a combination of biochemical techniques and multi-dimensional microscopy to analyze the subcellular distribution and spatial regulation of PKA, as well as its upstream regulators and downstream targets, during cell migration. The lab is also interested in the identification & characterization of changes in protein phosphorylation on a proteome-wide scale (phosphoproteomics), and the development of experimentally tractable cell culture systems for modeling metastasis and analyzing adhesion-related signaling events during metastatic cell migration.

Howe, AK, Baldor, LC, Hogan, BP. Spatial regulation of the cAMP-dependent protein kinase during chemotactic cell migration. Proc Natl Acad Sci USA (2005) 102:14320-5.

Howe AK, Hogan BP, Juliano RL. Regulation of vasodilator-stimulated phosphoprotein phosphorylation and interaction with Abl by protein kinase A and cell adhesion. J Biol Chem (2002) 277: 38121-38126

Howe AK. Cell adhesion regulates the interaction between Nck and p21-activated kinase. J Biol Chem (2001) 276:14541-14544.

Howe AK, Juliano RL. Regulation of anchorage-dependent signal transduction by protein kinase A and p21-activated kinase. Nat Cell Biol (2000) 2:593-600.

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• Senior Fellow, Foundation for Promotion of Cancer Research, National Cancer Institute, Japan, 1997;
• F33 International Fellow, European Institute of Oncology, Milan, Itlaly, 2001

Our laboratory studies the effect of environmental agents on cell cycle control in the pathogenesis of lung disease.  Using synchronized populations of lung epithelial cells, we assess the effects of agents such as nitrogen dioxide, hydrogen peroxide, and asbestos on three important transition points in the cell cycle:

1. transition from G0 to G1, with an emphasis on activation of the cyclin D1 gene by the transcription factors AP-1, NF-kB, and CREB,
2. transition through the G1 restriction point, with a focus on repression and activation of S phase genes by the E2F family of transcription factors, and
3. entry into the S phase, with an emphasis on the function of Cdc6 in origin activation. 

We also address the mechanism by which environmental agents activate cell cycle checkpoints, with a particular interest in the role of retinoblastoma protein in maintenance of the intra-S phase checkpoint in response to DNA damage.  Hypotheses developed during in vitro mechanistic studies are addressed by animal inhalation studies with wild-type and transgenic mice.  The laboratory also investigates new methods for modifying mammalian genes in bacterial artificial chromosomes by homologous recombination, and has refined novel technologies for introducing large genes into mammalian cells and animals.

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Sally A. Huber, Ph.D. (Professor, Department of Pathology)

• NIH Pathology A Study Section, 1999-2004
• American Heart Association Immunology and Microbiology I Study Section, 1997, 1999-2002

Dr. Huber's research group investigates the immunopathology of cardiovascular and infectious diseases. Research on myocarditis investigates how viruses, bacteria and drug hypersensitivity initiates pathogenic T lymphocyte immunity which causes myocyte apoptosis and necrosis. Emphasis is presently placed on upregulation of CD1 molecules and activation of T cells expressing specific types of T cell receptors, the gamma-delta T cell receptor (gamma delta TCR). These gamma delta+ cells belong to the "innate" immune response as the limited diversity of the TCR variable regions precludes highly heterogeneous antigen recognition as is seen with adaptive (antigen-specific alpha beta TCR+) T cells. Specifically, we have shown that gamma delta+ cells having a particular V gamma 4 TCR promote cellular immunity mediated by CD4+ Th1 cell responses whereas V gamma1+ cells in the gamma delta cell population promote CD4+ Th2 cell responses. We have shown that the V gamma 4+ cells are responsible for CD4+ Th1 cell responses and tissue injury in both virus-induced myocarditis and high cholesterol-induced murine atherosclerosis. Thus, the same population of gamma delta+ cells has the same biological function in diverse diseases irrespective of the type of initiating agent for the disease. We are presently collaborating with other investigators at UVM to investigate the interaction between oral microbiology and systemic disease (diabetes) and will be investigating whether specific gamma delta + cells in periodontal disease in response to bacterial infections correlate with diabetes. Since cytokines are considered major factors in insulin resistance, and innate immune factors such as gamma delta+ cells can be potent producers of cytokines, the type of innate immune response could have an important impact on promoting or suppressing susceptibility to various diseases.

Huber SA, Shi Cuixia, Budd RC. gd T cells promote a Th1 response during coxsackievirus B3 infection in vivo: role of fas and fas Ligand. J of Virology, 76(13):6487-6494, 2002.

Huber SA, Sartini D, Exley M: Vg+ T Cells Promote Autoimmune CD8+ Cytolytic T-Lymphocyte Activation in Coxsackievirus B3-Induced Myocarditis in Mice: Role for CD4+ Th1 Cells. J of Virology, 76(21):10785-10790, 2002.

Huber SA, Sartini D, Exley M: Murine CD1d in Coxsackievirus B3 Induced Myocarditis. J of Immunology 170:3147-3153, 2003.

Roessner K, Wolfe J, Shi C, Sigal L H, Huber S, Budd R C: High expression of Fas ligand by synovial fluid-derived gamma delta T cells in Lyme arthritis. J of Immunology 170: 2702-2710, 2003.

Gauntt C, Huber S: Coxsackievirus Eexperimental heart diseases. Frontiers of Bioscience 8:E23-35, 2003.

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• Chairman, Long Range Planning Committee, Respiratory Structure/Function Assembly, American Thoracic Society, 1995-1997;
• Chairman, Respiratory Structure/Function Assembly, American Thoracic Society, 1998-2000;
• Board of Directors, American Thoracic Society, 1998-2000

For information about Dr. Irvin's research, visit http://www.vermontlung.org

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Yvonne M.W. Janssen-Heininger, Ph.D. (Associate Professor, Department of Pathology)

• Jaap Swierenga Award, Dutch College of Chest Physicians, 1996;
• Senator Proctor Award, American Lung Association of Vermont; July, 1996-1997;
• Member, Environmental & Occupational Health Planning Committee, American Thoracic Annual Conference, 1998-2000;
• Member, Planning Committee, Respiratory Cell and Molecular Biology Assembly, American Thoracic Society Annual Conference, 1999-

The Janssen-Heininger laboratory is interested in the role of lung epithelial cells in asthma and related lung disorders.  Asthma is a disease that affects millions of Americans and is the leading cause of children missing school.  We study the molecular signaling events that dictate survival and death of the lung epithelium, since protracted turnover of lung epithelium is a critical factor in regulating lung remodeling.  The oxidant nitrogen dioxide is formed in lungs from asthmatics and believed to contribute to inflammation and airway injury.  The laboratory addresses the mechanisms by which nitrogen dioxide evokes damages lung epithelium and aggravates of inflammation.  Areas of investigation involve the transcription factor, nuclear factor kappa B and the death receptor, Fas.  We have generated a transgenic mouse model and will design a targeted knock-out animal to address the importance of these proteins in the disease pathology.

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The long-term objective of our research is to understand the mechanisms that control cellular morphogenesis during the eukaryotic cell cycle.  The spatial organization of the cell plays a crucial role in the control of a variety of cellular and developmental processes.  Normal morphogenesis is essential for the fidelity of cellular differentiation and reproduction.  A variety of environmental stresses, including radiation, hyperosmolarity, oxidative stress, and mutagens, lead to alterations in cellular morphogenesis and oncogenesis.  Several of the proteins involved in controlling morphogenesis in the budding yeast S. cerevisiae and the pathogenic yeast C. albicans, including the Cdc42pGTPase and its guanine-nucleotide exchange factor Cdc24p, have functional homologs in mammalian cells that have been implicated in these stress response pathways and in the cancer-causing process.

We also investigate the signal-transduction mechanisms that regulate the morphological transitions essential for the virulence of the pathogenic yeast Candida albicans.  C. albicans is the most frequently isolated fungal pathogen in humans and is a major opportunistic pathogen of immunocompromised hosts, leading to lethal systemic candidiasis.  There is strong evidence that the morphological state of C. albicans plays a role in its virulence capabilities, with the ability to switch between the yeast form and the filamentous forms being critical to virulence.  The yeast-to-hypha morphological switch is a result of changes in polarized growth patterns in response to different external and/or internal signals, including environmental stresses, nutrients, serum, and host macrophages.  In order to investigate the role of Cdc42p-dependent signaling pathways in C. albicans morphogenetic pathways, we are isolating and characterizing the CDC42 and CDC24 genes and studying the activation of the pathway in response to virulence signals such as environmental stresses (pH, temperature) or growth in serum.  These studies bring to bear a full arsenal of genetic, biochemical, and cell biological approaches to shed light on the role of this highly conserved signaling pathway in C. albicans morphogenesis and virulence, hopefully leading to new therapeutic targets.

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Steven Lidofsky, MD, PhD (Associate Professor of Medicine and Pharmacology)

Dr. Lidofsky's research concerns how the liver responds to stresses that perturb cell volume. Liver cells undergo dynamic changes in volume in response to nutrient uptake and metabolism, and irreversible cell swelling is a hallmark of liver injury. Thus, an understanding of cell volume regulation in particular is highly relevant to an understanding of liver pathobiology in general. It is known that in response to swelling, restoration of cell volume is achieved through fluid and electrolyte efflux through plasma membrane potassium and chloride channels, but the nature of the responsible volume sensors, signaling pathways, and ion channels is not well understood. We have found evidence for two distinct volume regulatory pathways in response to hepatocellular swelling, one which involves intracellular calcium mobilization through activation of phospholipase C gamma, and one which involves autocrine stimulation of purinergic receptors, each of which is necessary for potassium and chloride channel activation and volume recovery. Our current goals are to define the volume-sensitive activators of phospholipase C gamma, to elucidate the downstream mediators of volume-sensitive purinergic receptors, and to establish the molecular characteristics of volume-sensitive potassium and chloride channels. Resolution of these issues will provide new insights into cellular mechanisms of liver injury.

Publications since 2000:

Nietsch HH, Roe MW, Fiekers JF, Moore AL, Lidofsky SD. Activation of potassium and chloride channels by tumor necrosis factor alpha. Role in liver cell death. J Biol Chem. 2000;275:20556-20561.

Barfod ET, Moore AL, Lidofsky SD. Cloning and functional expression of a liver isoform of the small conductance Ca2+-activated K+ channel SK3. Am J Physiol. 2001;280:C836-C842.

Roe MW, Moore AL, Lidofsky SD. Purinergic-independent calcium signaling mediates recovery from hepatocellular swelling: implications for volume regulation. J Biol Chem. 2001;276:30871-30877.

Moore AL, Roe MW, Melnick RF, Lidofsky SD. Calcium mobilization evoked by hepatocellular swelling is linked to activation of phospholipase C gamma. J Biol Chem. 2002;277:34030-34035.

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Signaling mechanisms that regulate vascular growth are essential for preventing angiogenesis of tumor cells and vascular disease, yet many of these mechanisms are poorly understood.  Research in our laboratory is focused on understanding pathways by which growth signals generated at the plasma membrane are communicated to the nucleus of arterial cells.  Signaling pathways of current interest include calcium-regulated gene transcription, hypoxic stress signaling and growth factor/protein kinase cascades in vascular smooth muscle cells.  The laboratory uses a multidisciplined approach to study these pathways using techniques from biochemistry, molecular biology, and cell biology.  Calcium changes and location of signaling proteins are detected using fluorescent probes coupled with video microscopy such that in situ or live images of the cellular changes can be recorded. 

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Brooke T. Mossman, Ph.D. (Professor, Department of Pathology)

• Honorary Membership, The Oxygen Club of Greater Washington "For her studies on the role of oxidative damage in lung injury by asbestos and other toxic agents";
• Outstanding Volunteer Contribution Award, The Oxygen Society, Chair, Annual Meeting, 1998;
•       Keynote Speaker, "Fibre-induced Carcinogenesis", Fifth International Mesothelioma Interest Group (IMIG), October 5-8, 1999;
• Elected Member, Vermont Academy of Science and Engineering, 2000;
• Lung Biology and Pathology Study Section, NIH, July 1995-1999;
• Board of Scientific Counselors (Subcommittee on Basic Research), National Cancer Institute, 2000-2005.

Dr. Mossman's research group is studying the molecular mechanisms of chemical and physical carcinogenesis as well as mechanisms of toxicity and fibrotic lung disease caused by asbestos and other inhaled particulates (silica, glass and refractory ceramic fibers). She is also examining the relationship between active oxygen species and lung disease by these environmental pollutants.  Epithelial cells, mesothelial cells and fibroblasts of the respiratory tract in both cell and organ cultures are used to evaluate molecular, cytotoxic and proliferative changes after exposure to asbestos and other compounds. One of several projects is aimed at dissecting second messenger pathways including alterations in protein kinases and cell signaling events which may be involved in causing changes in gene expression. Another area of interest is determining the molecular mechanisms of increased cell proliferation by agents focusing on cell signaling pathways, transcription and replication factors, and activation of protooncogenes.  Dr. Mossman and coworkers are using in vitro systems of oxidant generation to induce many of the changes observed in cells of the respiratory tract after addition of asbestos.  Administration of scavengers of free radicals to both cells in culture and a rodent inhalation model of disease indicates that these agents can prevent asbestos-induced cytotoxicity and tissue damage. 

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Our research focuses on mechanisms of DNA replication, recombination and repair in the bacteriophage T4 system.  Particular areas of emphasis include: 

1. physical biochemistry and structural biology of protein-DNA complexes;
2. mechanism of assembly of the T4 presynaptic recombination filament;
3. mechanism of DNA helicase acquisition by the T4 DNA replication fork;
4. mechanisms of recombination-dependent replication (RDR) and repair processes; and
5. mechanisms of error-prone and error-free bypass of lesions by DNA polymerases.  Experimental approaches include quantitative analysis of protein-DNA and protein-protein interactions, enzyme kinetics, thermodynamics, fluorescence and CD spectroscopy, analytical ultracentrifugation, X-ray crystallography, molecular biology and mutagenesis.

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Matthew D. Rand, Ph.D. (Research Assistant Professor, Department of Anatomy and Neurobiology)

The overall goal of our research is to identify fundamental mechanisms of neural development that are preferentially sensitive to perturbation by environmental factors.

Link to Dr. Rand's web site at UVM

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Mercedes Rincon, Ph.D. (Assistant Professor, Department of Medicine)

Our laboratory is determining the molecular mechanisms of several aspects of the T cell mediated immune response. Specifically, we are studying

1. the role of the JNK signaling pathway in CD4⁺ Th1 and Th2 differentiation using mice deficient for JNK1 or JNK2. More recently we have also expanded our interest towards the role of JNK1 and JNK2 in CD8⁺ T cell activation.  In addition, we are using new approaches to determine why JNK1 and JNK2 are expressed in most tissues except resting T and B cells;
2. the role of p38 MAP kinase in production of IFN gamma and death of CD8⁺ T cells. We have performed microarray assays using RNA for wild type CD8⁺T cells and CD8⁺ T cells from transgenic mice in which p38 MAP kinase is constitutively activated. A number of genes were identified using this approach, and we are characterizing and determining the role of these genes in induction of cell death. We are also determining the role of p38 MAP kinase in development of arthritis in Lyme disease;
3. the role of the p38 MAP kinase signaling pathway in differentiation and cell cycle progression of developing thymocytes during embryogenesis;
4. the regulation and the role of NFAT transcription factors in differentiation and cell cycle progression of developing thymocytes during embryogenesis;
5. the molecular mechanisms by which IL-6 inhibits Th1 differentiation (by inducing SOCS1 gene expression) and promotes Th2 differentiation (by activating NFAT transcription factors), and its implications in the development of asthma;
6. the differential regulation and the role of NFAT transcription factors in naïve, effector and memory CD4⁺ T cells.  Moreover, we are also examining the role of IL-6 in multidrug resistance of tumor breast cancer cells, and we are performing a prospective study on expression of IL-6 in tumor tissue from breast and ovarian cancer patients.

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Albert van der Vliet, Ph.D. (Associate Professor, Department of Pathology)

• American Heart Association Study Group NorthEast Affiliate 2 (Lipoproteins, Lipid Metabolism & Nutrition/Throm/VWB), 2004-2006.
• Council Member, Society for Free Radical Biology and Medicine, 2004-2008.
• Chair, PPG Special Review Panel, NIEHS, 2004-2005.
• NIH Study Section - LIRR (Lung Injury, Repair, and Remodeling), 2003-2005 (ad hoc), 2006-2009.

Research in our laboratory is centered around biochemical mechanisms in redox signaling pathways in the airway that are mediated by environmental oxidants and electrophiles, and by endogenous activation of nitric oxide synthase (NOS) and NADPH oxidase in the airway epithelium. Proteomic approaches are being developed to identify critical redox-sensitive targets in cellular and extracellular signaling pathways that control inflammation and apoptotic cell death. A specific research direction is to eludicate the roles of epithelial NOS and/or NADPH oxidases in epithelial barrier function and repair processes following injury, with specific emphasis on the regulation of matrix metalloproteinase expression and activation.

J.P. Eiserich, M.Hristova, C.E. Cross, A.D. Jones, B.A. Freeman, B. Halliwell and A. van der Vliet (1998) Formation of nitric oxide-derived inflammatory oxidants by myeloperoxidase in neutrophils. Nature 391, 393-397.

A. van der Vliet, M. Hristova, C.E. Cross, J.P. Eiserich and T. Goldkorn (1998) Peroxynitrite induces covalent dimerization of epidermal growth factor receptors in A431 epidermoid carcinoma cells. J. Biol. Chem. 273, 31860-31866.

A. van der Vliet, M.N. Nguyen, M.K. Shigenaga, J.P. Eiserich, G.P. Marelich, and C.E. Cross (2000) Myeloperoxidase and protein oxidation in cystic fibrosis. Am. J. Physiol. 279, L537-L546.

T. Okamoto, T. Akaike, T. Sawa, Y. Miyamoto, A. van der Vliet, and H. Maeda (2001) Activation of matrix metalloproteinases by peroxynitrite-induced protein S-glutathiolation via S-oxide formation. J. Biol. Chem. 276, 29596-29602.

P.S. Wong, J.P. Eiserich, C.L. Lopez, A.D. Jones, S. Reddy, C.E. Cross and A. van der Vliet (2001) Inactivation of glutathione S-transferase by nitric oxide-derived oxidants. Exploring a role for tyrosine nitration. Arch. Biochem. Biophys. 394, 216-228.

Finkelstein, E.I., M. Nardini, and A. van der Vliet (2001) Inhibition of neutrophil apoptosis by acrolein: A contributing factor in tobacco-related inflammatory lung disease? Am. J. Physiol. 281, L732-L739.

T. Okamoto, G. Valacchi, K. Gohil, T. Akaike, and A. van der Vliet (2002) S-Nitrosothiols inhibit cytokine-mediated induction of MMP-9 in airway epithelial cells. Am. J. Respir. Cell Mol. Biol. 27, 463-473.

S. Reddy, E.I. Finkelstein, P.S.-Y Wong, A. Phung, C.E. Cross, and A. van der Vliet (2002) Identification of glutathione modifications by cigarette smoke. Free Rad. Biol. Med. 33, 1490-1498.

N.L. Reynaert, K. Ckless, S.H. Korn, N. Vos, A.S. Guala, E.F.M. Wouters, A. van der Vliet, and Y.M.W. Janssen-Heininger (2004) Nitric oxide represses inhibitory kappa B kinase through S-nitrosylation. Proc. Natl. Acad. Sci. USA 101, 8945-8950.

K. Ckless, N.L. Reyneart, D.J. Taatjes, K.M. Lounsbury, A. van der Vliet, and Y. Janssen-Heininger (2004) In situ detection and visualization of S-nitrosylated proteins following chemical derivatization. Nitric Oxide: Chemistry and Biology 11, 216-227.

E.I. Finkelstein, J. Ruben, C.W. Koot, M. Hristova, and A. van der Vliet (2005) Regulation of constitutive neutrophil apoptosis by the a,b-unsaturated aldehydes acrolein and 4-hydroxynonenal. Am. J. Physiol 289, L1019-1028.

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Douglas J. Taatjes, Ph.D. (Research Professor, Department of Pathology)

• Elected President of New England Society for Microscopy, 1998;
• Editor, Cell Imaging Techniques, "Methods in Molecular Biology", Humana Press, 2002

Dr. Taatjes is Director of the Microscopy Imaging Center and is engaged in a number of research projects with Drs. Mossman, Janssen-Heininger and Heintz, involving confocal microscopy, atomic force microscopy, image analysis, and immunocytochemistry.  One of these projects concerns co-localization of protooncogenes in proliferating and/or apoptotic cells after exposure to oxidants. 

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• Working Group Leader, National Research Council Workshop:  Biologically-based Risk Model for Low Dose/Low Dose Rate High LET Radiation, 1996;
• Failla Awardee and Memorial Lecturer, 1996;
• Chair, NCI Workshop:  Molecular Biology to Radiation Oncology, 1997;
• Member and Treasurer, Vermont Academy of Sciences and Engineering, 1995-present;
• Gordon Mutagenesis Conference, Vice Chair, Chair (elected), 1995, 1998;
• American Society for Microbiology, Co-Chair with G. Walker and E. Friedberg, International Congress on DNA Damage and Repair, 1999;
• NIH Merit Award, 1995 - 2003;
• Radiation Research (Senior Editor), 2001-present
• Board of Directors, FASEB, 2000-2003

Dr. Wallace's research focuses on understanding at the molecular level, the processing of oxidative DNA damages.  Oxidative DNA damages are produced by free radicals known to be the mediators of the mutagenic and carcinogenic effects of a wide variety of environmental agents as well as ionizing radiation and normal cellular metabolism.  Free radicals produce a plethora of damages in DNA, over 100 different kinds of lesions.  This makes it difficult to understand which lesions are important for biological consequences.  To address this problem, Dr. Wallace's group has synthesized a large number of model, stable DNA lesions and introduced these into DNA molecules and oligonucleotides for use as substrates for DNA repair enzymes, RNA polymerases and DNA polymerases.  Repair of oxidative damage which takes place through base excision repair is being studied using biochemical, molecular, x-ray crystallographic and computational techniques as well as pathway analysis using microorganisms as well as human cells in culture.  The interaction of oxidative lesions with DNA polymerases, a predictor of cytotoxicity and mutagenicity, has been extensively examined in vitro using DNA polymerases in an attempt to elucidate the features of the lesions, including surrounding sequences, that influence the formation of the polymerase-primer terminus-incoming deoxynucleotide triphosphate ternary complex which in turn determines the potential biological outcome.  The predictions from these studies have been tested in vivo using mutagenicity assays in mammalian and bacterial cells. The Environmental Pathology Trainees have participated in all of these activities with emphasis on the potential consequences of environmental agents by virtue of their action on DNA.

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