Sudhakar Jinka, Ph.D.

Sudhakar
Jinka, Ph.D.
Postdoctoral Research Fellow
Deborah Lannigan Lab
sudhakar.jinka@vumc.org

Tamara Machado, Ph.D.

Tamara
Machado, Ph.D.
Postdoctoral Research Fellow

Originally from Brazil, Sao Paulo, Tamara is a Biologist and earned her PhD in Biosciences and Biotechnology Applied to Pharmacy/Bacteriology from UNESP -São Paulo State University, Brazil. She is currently investigating the role of diet and gut microbiota members in the development of colorectal cancer. In her free time she enjoys hanging with her family and her lovely dogs, and sometimes cooking or watching TV series. She loves to travel abroad, experience new cultures, and make new friends.

Mariana Byndloss Lab
tamara.r.machado.ribeiro@vumc.org

Martin Douglass Ph.D.

Martin
Douglass Ph.D.
Postdoctoral Research Fellow

Marty was born and raised in Long Beach, CA, and earned his B.S in Microbiology at California State University Long Beach. For his doctoral work, he studied in the laboratory of Dr. Stephen Trent at the University of Georgia, where he used genetic approaches to understand lipid transport to the outer membrane of Gram-negative bacteria. In the Skaar lab, Marty is studying how C. difficile responds to host-mediated immune responses.

Eric Skaar Lab
Martin.V.Douglass@vumc.org

Juan Barraza Ph.D.

Juan
Barraza Ph.D.
Postdoctoral Research Fellow

Juan was born in Mexico City and earned his B.S. in Biochemistry from the University of Texas at Austin. He started his graduate work in Austin with Marvin Whiteley and moved with his lab to Georgia Tech, where he obtained his PhD. His work focused on the development of tools for characterizing the spatial structure of microbial communities within the context of infectious diseases. In 2022, Juan started his postdoctoral work in a joint venture with the Cassat and Skaar lab at the Vanderbilt Institute for Infection, Immunology and Inflammation. His project incorporates quantitative imaging, clinical samples and single cells assays to answer basic questions about host-pathogen interactions in the gut. He is an avid cyclist, live music enthusiast and is working towards developing a world-class taco experience from his kitchen.

Eric Skaar & James Cassat Labs
Juan.Barraza@vumc.org

Melanie McKell Ph.D.

Melanie
McKell Ph.D.
Postdoctoral Research Fellow

Melanie grew up in Cincinnati, OH and received her B.S. in Microbiology from Miami University. After graduating, she pursued her Ph.D. in Immunology from the University of Cincinnati and performed her graduate work at Cincinnati Children’s Hospital Medical Center in the laboratory of Dr. Joseph Qualls. During her graduate work, she studied the effects of the amino acid L-arginine on macrophage host defense against Mycobacterium tuberculosis. In the Skaar lab, Melanie studies the effects of nutrient zinc on the host-pathogen interface during Acinetobacter baumannii infection.

Eric Skaar Lab
melanie.mckell@vumc.org

Rachel Henry Bonami, Ph.D.

Rachel
Henry
Bonami, Ph.D.
Assistant Professor of Pathology, Microbiology and Immunology
Assistant Professor of Medicine

​Type 1 diabetes occurs as the result of autoimmune destruction of beta cells in the pancreas. This attack arises in part through autoreactive B lymphocyte presentation of islet antigens to cognate T lymphocytes. Dr. Rachel Bonami’s research is focused on understanding how these cognate T-B interactions can be disrupted to prevent type 1 diabetes. Islet autoantibodies, the product of these interactions, serve as biomarkers for disease risk. The presence of insulin autoantibody is particularly predictive of disease onset in young patients, highlighting insulin as a critical autoantigen in this disease process. Dr. Bonami has shown that anti-insulin B lymphocytes can be selectively eliminated using a monoclonal antibody to prevent type 1 diabetes in a preclinical model. This work received a Faculty of 1000 recommendation and suggests that such an approach holds promise for the prevention of type 1 diabetes without exposing patients to broad immunosuppression. Dr. Bonami’s work has also focused on identifying and correcting defects in immune tolerance mechanisms in the setting of autoimmune disease. She was previously awarded a postdoctoral fellowship by the Juvenile Diabetes Research Foundation and was invited to present her work at Keystone Symposia and at the American Association of Immunologists annual meeting. In 2015 the Vanderbilt Diabetes Research and Training Center presented her with the Daryl K. Granner Scholar in Diabetes Postdoctoral Fellow Award, Ph.D..

Dr. Bonami has received a grant from the Juvenile Diabetes Research Foundation (JDRF). This is a 3-year Strategic Research Agreement. Here is a summary of her research project: Abnormalities in the immune system are present long before Type 1 diabetes is diagnosed in the clinic, as indicated by the early presence of islet autoantibodies in the pre-symptomatic stages of the disease. We do not yet understand the immune system glitches that push B lymphocytes to inappropriately respond to islet autoantigens, engage autoreactive T cells, and morph into autoantibody-secreting cells. Our objectives are: 1) To immunologically define how B lymphocyte recognition of beta cells evolves during the early stages of disease, and 2) To discover which B lymphocyte subsets harbor insulin autoimmunity during the pre-symptomatic period. We expect this information about the early disease process to highlight novel characteristics of B lymphocytes to target for T1D prevention.

rachel.h.bonami@vumc.org

B cell, T cell, autoimmunity, type 1 diabetes, arthritis, microbiome

Justin M. Balko, Pharm.D., Ph.D.

Justin
Balko, Pharm.D., Ph.D.
Associate Professor of Pathology, Microbiology and Immunology
Associate Professor of Medicine
Associate Professor of Cancer Biology

Our laboratory is focused on improving treatment oucomes in breast cancer (particularly triple-negative breast cancer) as well as in other solid tumors. To accomplish this, we integrate data from genomic and molecular profiling studies with molecular biology and signal transduction methodologies to translationally identify altered pathways in cancer, the functional consequences of these alterations, and ways to directly target them in patients to improve clinical outcomes and survival. These efforts span in silico (publically available databases), in vitro (cell culture), in vivo (mouse and human clinical studies) and in situ (histology) methods. We have a strong interest in the intersection between new immunotherapies and tumor cell signaling pathways.

We are currently exploring ways of targeting drug-resistant tumor cells which persist after neoadjuvant chemotherapy (NAC). NAC is used increasingly in patients with triple-negative breast cancer (TNBC), which does not express estrogen receptor, progesterone receptor or human epidermal growth factor-2 (HER2) amplification. The purpose of NAC is to increase the patient's chances of undergoing breast-conserving surgery and to eliminate clinically silent micro-metastases. When employed, NAC results in pathological complete response (pCR) in about 30% of TNBC patients. These patients have a favorable recurrence-free and overall survival. The remaining patients with residual viable cancer in the breast or lymph nodes exhibit high rates of metastatic recurrence and an overall poor long term outcome.

Importantly, there are no approved therapies for use in TNBC patients with residual disease at surgery following NAC. For these patients, the standard of care is watchful waiting. In light of this, we performed molecular profiling of the residual disease from such patients in order to identify clinically actionable alterations that could be exploited therapeutically to reduce recurrence and mortality. From these studies, we have identified loss of dual specificity phosphatase 4 (DUSP4) in a significant percentage of post-NAC TNBCs (Balko et al, Nature Medicine, 2012) . DUSP4 is a phosphatase which negatively regulates the MEK and JNK signaling pathways and is a potential tumor suppressor. We have recently shown that DUSP4 regulates cancer stem cell-like phenotypes and chemotherapeutic resistance (Balko et al, Cancer Research, 2013). Furthermore, our mechanistic studies suggest that DUSP4-deficient breast tumor models are targetable by inhibitors of MEK or ERK.

We have also recently used targeted next-generation sequencing to characterize the spectrum of tumor-genome lesions in a series of 74 post-NAC TNBCs and have detected several potentially actionable molecular alterations (Balko et al, Cancer Discovery, 2014). Importantly, several of these alterations (including amplification of MCL1, JAK2, and loss of PTEN) are enriched in residual drug-resistant tumors after chemotherapy compared to primary untreated tumors. These data suggest additional actionable molecular targets which could be exploited in the adjuvant setting to reduce recurrence and improve survival of this devastating disease, and validation of these concepts will also be a continuing focus of the laboratory.

justin.balko@vumc.org

Translational cancer research focused on molecular therapeutics, onco-immunology & bioinformatics

Amanda C. Doran, Ph.D., M.D.

Amanda
Doran, Ph.D., M.D.
Assistant Professor of Pathology, Microbiology and Immunology
Assistant Professor of Medicine
Assistant Professor of Molecular Physiology & Biophysics

Dr. Doran’s research interest is in the cellular-molecular biology of cardiometabolic disease. In particular, she is interested in mechanisms by which the immune system modulates the development of advanced atherosclerosis and promotes the resolution of inflammation. In addition, she has a clinical interest in preventive cardiology and lipidology.

amanda.c.doran@vumc.org

Cellular-molecular biology of cardiometabolic disease.

Wenhan Zhu Ph.D.

Wenhan
Zhu, Ph.D.
Assistant Professor of Pathology, Microbiology and Immunology
Medical Center North
1161 21st Avenue South
Room / Suite
U-2215 MCN
Nashville
Tennessee
37232

In our lab, we focus on the metabolic interactions that dictate the changes or resilience of the microbiota. Insight into such interactions would enable precise manipulation of gut microbiota composition, thus restoring a balanced community in situ and improving host health. To precisely manipulate the microbiota, we use a multidisciplinary discovery pipeline that consists of next-generation sequencing, bacterial genetics and a mechanistic understanding of bacterial physiology in vivo. This pipeline allows us to discover druggable targets of the microbiota and translate our finding using high-throughput screening.

wenhan.zhu@vumc.org

Resilience mechanism of gut commensals, metabolic targeting of gut microbes to promote commensal resilience, and the roles of bacterial toxin in promoting colorectal cancer development