Our laboratory studies the cellular signaling systems in macrophages that are activated through pattern recognition receptors (PRRs) to drive inflammatory disease. The two primary systems we study are toll-like receptor (TLR) pathways, and NOD-like receptor (NLR) pathways. We use high-throughput genetic screening to identify key pathway regulators and a combination of cell biology, biochemistry, and molecular biology to characterize their function. Our goal is to obtain a better understanding of how innate immune signaling pathways control the macrophage inflammatory state, and ultimately to develop strategies to regulate these responses in human inflammatory diseases. Specific projects of our research group members in this context are described in their Bio sections below.
Signaling Systems Section, May 2025. Front Row (left to right): Brendan Geesey, Postbaccalaureate Fellow; Andrew Lin, Postbaccalaureate Fellow; Allison Rattay, Postbaccalaureate Fellow; Gurleen Kaur, Postbaccalaureate Fellow, Leilei Xu, Postdoctoral Fellow. Back Row (left to right): Sinu John, Staff Scientist; Ronit Schwartz Wertman, Postdoctoral Fellow; Asmaysinh Gharia, Graduate Student; Iain Fraser, Senior Investigator; Clinton Bradfield, Research Fellow; Kim Tindal, LISB Program Specialist; Jing Sun, Research Biologist.
Iain Fraser, Ph.D.
Chief, Signaling Systems Section
Specialty(s): Allergy and Immunology, Infectious Disease
Education:
Ph.D., Imperial College, University of London
Clinton Bradfield, Ph.D.
Research Fellow
Education:
Ph.D., microbial pathogenesis, Yale University
M.S., microbial pathogenesis, Yale University
B.A., Biochemistry, Simpson College
Clinton Bradfield is a Research Fellow in the Signaling Systems Section. Originally from Essex, Iowa, he received his BA in Biochemistry from Simpson College where he discovered his interest in molecular biology, organic chemistry, and microbial pathogenesis. Following early exposure to transcriptional analyses (P. Singer), chemical synthesis (T. Nguyen), and viral replication (R. Roller, M. Robek...
Brendan Geesey, B.S.
Research Fellow
Education:
B.S., Arizona State University
Brendan Geesey is a postbaccalaureate researcher who joined the group in the summer of 2023. He completed his bachelor’s degree in genetics, cell, and developmental biology at Arizona State University (ASU). While at ASU, Brendan worked with Dr. Karen Anderson on a project exploring T-cell immunity to SARS-CoV-2. His current project is aimed at identifying novel regulators of pyroptosis, the pro...
Asmaysinh Gharia
Graduate Student
Education:
NIH Oxford-Cambridge
University of California Berkeley
Sinu P. John, Ph.D.
Staff Scientist
Education:
Ph.D., 2006, University of Alabama, Birmingham, AL, USA
M.Sc., 1999, University of Hyderabad, India
Languages Spoken: Malayalam
Dr. John received a master’s degree in biochemistry from the University of Hyderabad, India and his Ph.D. in biochemistry and molecular genetics from the University of Alabama at Birmingham. He conducted postdoctoral research in the functional genomics of virus-host interactions at Harvard Medical School and the Ragon Institute of Mass General, MIT, and Harvard. Dr. John joined the Signaling...
Gurleen Kaur, B.S.
Postbaccalaureate Fellow
Education:
B.S., Western Michigan University
Gurleen Kaur is a postbaccalaureate fellow who joined NIH in 2024. She graduated from Western Michigan University, where she majored in biomedical sciences. As an undergraduate researcher in Dr. Benjamin Koestler's lab, Gurleen engineered transcriptional reporters to identify the Shigella flexneri protein that binds to formate, a byproduct of mixed-acid fermentation, and enhances virulence. Her...
Andrew Lin, B.S.
Postbaccalaureate Fellow
Education:
B.S., University of California San Diego
Andrew Lin is a postbaccalaureate fellow who joined the Signaling Systems Section in 2024. He completed his undergraduate studies at UC San Diego where he majored in Molecular and Cell Biology. There, his research focused on population genetics (Dr. Tatum Simonson) and extracellular vesicles (Dr. Louise Laurent). At the NIH, he looks at the cellular signaling events that occur to induce the...
Allison Rattay, B.S.
Postbaccalaureate Fellow
Education:
B.S., Ohio State University
Allison Rattay is a postbaccalaureate fellow who joined the NIH after graduating from Ohio State University in May of 2024. She majored in biochemistry and worked as an undergraduate researcher synthesizing polymeric nanomaterials for drug delivery. Her current research in Signaling Systems Section involves identifying new molecules that induce trained immunity with the potential to be developed...
Ronit Schwartz Wertman, Ph.D.
Postdoctoral Fellow
Education:
Ph.D., University of Pennsylvania
Ronit Schwartz Wertman joined the Signaling Systems Section in 2024 as a postdoctoral fellow. She obtained her Ph.D. at the University of Pennsylvania under the mentorship of Igor Brodsky, studying cell death signaling in the context of bacterial infections. Ronit received her B.S. from the Johns Hopkins University in 2018, after which she spent a year at NIDDK as a postbaccalaureate fellow...
Jing Sun, Ph.D., M.D.
Biologist
Education:
Ph.D., Peking University, China
M.D., Peking University, China
Jing Sun is the Ph.D. level Biologist in the Signaling Systems Section. She received her Ph.D./M.D. from Peking University, China, and was trained at Harvard Medical school and NIH before promotion to the Biologist position in 2014. Jing is currently leading multiple projects investigating mechanistic aspects of TLR signaling, with a particular focus on IRAK function and the role of Ubiquitin...
Leilei Xu, Ph.D.
Postdoctoral Fellow
Education:
Ph.D., Biology, University of Science and Technology of China
Languages Spoken: Chinese
Former Research Group Members
Julia Gross
Postdoctoral Fellow
NYU
Julia Gross was a graduate student in the NIH GPP/Emory IMP program from 2020-2025. She studied as an undergrad at Brown University before completing her thesis research jointly in David Weiss’ lab at Emory and the Signaling Systems Section at NIAID. Her project was centered on understanding how different types of antibiotic treatments impact patients’ immune responses to bacterial infections. More broadly she was interested in research on innate immune signaling writ large as well as anything and everything to do with understanding and combatting the increasing threat of antimicrobial resistant bacteria. Her thesis research was published in Nature Communications.
Chloe Hicks, B.S.
Medical Student
Yale University Medical School
Chloe Hicks was a postbaccalaureate from 2023-2024 following her graduation from Duke University. She majored in biology with a concentration in pharmacology and worked as an undergraduate student in a research lab studying the signaling mechanisms of G protein-coupled receptors. In the Signaling Systems Section she studied the dynamic role of reactive oxygen species and phosphorylation in regulating distinct signaling events following inflammasome activation. Her research interests also included mechanisms of immune dysregulation and using/developing microscopy-based biosensors to study signal transduction networks.
Heera James, B.S.
Medical Student
Kent State University College of Podiatric Medicine
Heera James was a postbaccalaureate fellow from 2022-2024 following her graduation from Virginia Commonwealth University, where she majored in biology and minored in chemistry. Her work in the Signaling Systems Section revolved around leveraging the applications of trained immunity to epigenetically rewire immune cells to combat viral infection and harness the associated pathology.
Christine Perritano, B.S.
Research Specialist
Georgetown University
Christine Perritano was a postbaccalaureate fellow in the Signaling Systems Section (SSS) from 2023-2024. She received her Bachelor of Science degree in molecular and cellular biology with a minor in French language, literature, and culture from the George Washington University in Washington, DC, in 2022. In the SSS she optimized a high-throughput assay to screen for potential trained immunity metabolites using an endogenous TNF reporter assay. After validation of primary screen hits through multiple secondary screening assays, these novel trained immunity-inducing metabolites were tested as potential therapeutics in people living with HIV and also have applications in cancer biology.
Rahul Basu, Ph.D.
HHMI Research Specialist II
University of Texas Health San Antonio
Rahul was a postdoctoral fellow under the Rocky Mountain Lab (RML) Bethesda (Rocky-Beth) collaborative program from 2017-2022. He received his Ph.D. from the Indian Institute of Science Education and Research in Kolkata, India where his project was directed to understand the changes in neuroglial interaction in a murine coronavirus infection model. In 2017, he joined Dr. Karin Peterson’s Neuroimmunology Section at RML to study the age-related changes in blood-brain barrier permeability that contribute to La Crosse virus (bunyavirus) susceptibility in children. Through the Rocky-Beth program, he transitioned to the Signaling Systems Section in 2019 to perform focused genetic screening and host-factor targeting in La Crosse virus infection. This study was published in Nature Communications.
Makheni Jean Pierre
Graduate Student, Eric Dang lab
NIH-Georgetown University Partnership Program
Makheni was a postbaccalaureate fellow in the Signaling Systems Section from 2020-2022, funded through the NIH Undergraduate Scholarship Program (UGSP). He obtained his associate degree in science from Queensborough Community College (QCC New York) and then transferred to Stony Brook University to complete his bachelor’s in biology. His interest lay in the intracellular signaling processes in macrophages in response to activation by pathogens. He worked on a target protein discovered in a genetic screen that regulates the expression of key genes involved in the TLR4 pathway in macrophages in order to control the degree of immune response in certain situations.
Sam Katz, Ph.D.
Senior Scientist
Verily Biosciences
Sam was a graduate student in the NIH-OxCam program from 2016-2020 and then remained in the Signaling Systems Section as a postdoctoral fellow until 2022. He received his Ph.D. from the University of Cambridge in 2020 (co-supervised by Dr. Fraser and Professor Clare Bryant). As a graduate student, Sam built the SIGNAL platform for prioritizing candidates from high-throughput studies. He then focused on characterizing how post-translation modifications, such as alternative splicing, regulate the inflammatory response.
Camille Lake, Ph.D.
Senior Bioinformatics Data Scientist
Deloitte Consulting, LLP
Camille Lake was a rotating fellow in the Signaling Systems Section when she was part of NIAID’s Emerging Leaders in Data Science Fellowship program from 2021-2022. She spent her upbringing in the hills of Northern California and eventually moved to Santa Barbara, where she got her college degree and discovered her love of molecular biology. She moved to Bethesda, MD, to pursue her Ph.D. in infectious diseases and immunology at the Uniformed Services University of the Health Sciences, where she graduated in 2021. She utilized her immunology foundation and fascination with data science to fuel her research, which ranged from determining the underpinnings of molecular mimicry in SARS-CoV-2 sequelae to utilizing machine learning algorithms to unlock the secrets of RNA regulation.
Jonathan Liang, Ph.D.
Medical Intern
Yale University Medical School
Jonathan is an M.D./Ph.D. student who completed his graduate work in the Signaling Systems Section (SSS) in 2022 through the NIH-OxCam Scholars Program. He is a Washington, DC, area native, having lived near NIH since middle school. After undergraduate studies at Yale University in New Haven, CT, he completed a master’s degree at the University of Cambridge before beginning his M.D./Ph.D. jointly between the Yale School of Medicine, the NIH, and the University of Cambridge. His research in the SSS sought to understand the molecular pathways that allow saturated fatty acids to trigger the NLRP3 inflammasome, an interaction that may contribute to inflammation in diseases such as atherosclerosis and fatty liver disease (recently reviewed in Trends in Immunology). His major ongoing clinical interest is in pediatrics.