Principal Investigator

Jonathan P. Jacobs, MD, PhD

Jonathan P. Jacobs, MD, PhD
Assistant Professor-in-Residence
Vatche and Tamar Manoukian Division of Digestive Diseases
David Geffen School of Medicine at UCLA

Dr. Jacobs graduated magna cum laude with highest honors from Harvard University with an AB in biochemistry. He subsequently received his MD from Harvard Medical School, graduating magna cum laude in a special field. During college and medical school, he trained in the laboratory of Diane Mathis and Christophe Benoist where he investigated the immunologic mechanisms of an autoantibody-mediated model of arthritis. This research was supported by a fellowship from the Howard Hughes Medical Institute and resulted in three first-author publications, including one in Proceedings of the National Academy of Science. He completed a residency in internal medicine at Stanford University then joined UCLA as a gastroenterology fellow in 2010. He pursued additional research training at UCLA through the Specialty Training and Advanced Research (STAR) program under the mentorship of Jonathan Braun. He was awarded a PhD in cellular and molecular pathology in 2015 and afterwards joined the UCLA Division of Digestive Diseases faculty. He co-founded the UCLA Microbiome Center in 2015 and now directs the Microbiome Core, which provides a comprehensive suite of microbiome-related services to support microbiome research by the UCLA scientific community.

Dr. Jacobs’ research explores the role of intestinal microbes in the development of inflammatory bowel disease (IBD) and other gastrointestinal disorders. This involves a translational approach that includes detailed characterization of patients’ microbiome by 16S ribosomal RNA sequencing, metagenomics, and metabolomics as well as modeling of the effect of disease-associated human microbial communities in humanized gnotobiotic mice (i.e. germ-free mice colonized with human microbiota). His research has been published in a number of scientific journals including Gastroenterology, Cellular and Molecular Gastroenterology and Hepatology, Gut Microbes, Genome Medicine, Scientific Reports, and Microbiome. He also authored a review article, commentary, and two textbook chapters on intestinal host-microbiome interactions. His ongoing projects employ animal models and multi’omics analysis of patient cohorts to define the role of IBD-associated genes in shaping the intestinal microbiome and to identify microbes and microbial products that promote IBD, irritable bowel syndrome, obesity, and other diseases.

David Meriwether, PhD

David Meriwether, PhD

Project Scientist

Dr. Meriwether received his PhD in molecular and medical pharmacology from UCLA. After three years of post-doctoral training in the laboratory of Drs. Srinu Reddy and Alan Fogelman, he joined the Division of Digestive Diseases in July 2021 as a project scientist affiliated with the laboratories of Drs. Jonathan P. Jacobs and Martin Martin. Dr. Meriwether is an intestinal epithelial and inflammation biologist who investigates the etiology and pathogenesis of inflammatory bowel disease.

Georgina Xanthou, PhD

Georgina Xanthou, PhD

Visiting Scientist

Dr. Xanthou completed her undergraduate studies at the University of Athens in the Department of Biology and received her PhD in immunology from the University of Athens, Medical School. Dr. Xanthou performed her post-doctoral studies at the Leukocyte Biology Section in Imperial College as an EMBO-funded research fellow, wherein she delineated novel molecular mechanisms through which Th1 cell-associated chemokines regulate Th2 cell-driven allergic responses.

Hyo-Joon Yang, MD

Hyo-Joon Yang, MD

Visiting Scientist

Dr. Yang is an associate professor at Kangbuk Samsung Hospital, South Korea. His research interest includes gastric and fecal microbiome and epigenetics in gastric cancer. He received a research grant from the National Research Foundation of Korea and is currently studying gastric microbiome associated with gastric cancer. Dr. Yang will focus on intestinal bacterial and fungal microbes associated with long-term clinical outcomes in IBD.

Diana Chernikova, MD, PhD

Diana Chernikova, MD, PhD

Allergy-Immunology Fellow

Dr. Chernikova obtained her BS in engineering sciences at UC Berkeley, followed by a 2-year post-baccalaureate IRTA research fellowship at the NIH in Dr. Eugene Koonin’s computational genomics lab. She completed her MD-PhD at Dartmouth Medical School with her PhD thesis on comparing gut microbiome composition in premature infants and infants with cystic fibrosis to that of healthy infants. She completed her pediatrics residency program at Harbor-UCLA Medical Center.

Carolina Koletic, MD

Carolina Koletic, MD

Pediatric GI Fellow

Dr. Koletic earned her bachelors of science degree in anthropology at UCLA and her medical doctorate degree at the University of Zagreb School of Medicine. Since college her passion has been to help children manage chronic disease so that they may fulfill their potential as adults. She is an active volunteer since 2007 at Camp Conrad Chinnock, a youth type-1 diabetes camp where she conducted her undergraduate honors thesis studying the socialization of youth with type-1 diabetes.

Ezinne Aja, PhD

Ezinne Aja, PhD

Staff Research Associate

Dr. Aja is a researcher who has a passion for microbiology. She enjoys working with bacteria—especially anaerobic bacteria and is also interested in the role of the microbiome in various disease states. She studied microbiology in her undergraduate degree and obtained a PhD in microbiology and molecular genetics. Her doctoral work evaluated the role of various genes in oxidative stress resistance in oral bacteria and she assigned function to a hypothetical protein in Filifactor alocis.

Candace Chang

Candace Chang

Graduate Student

Candace is a PhD student in the Molecular Toxicology Program under the joint mentorship of Dr. Jacobs and Dr. Jesus Araujo. In 2017, She completed her BS at UCLA in environmental science with a concentration in environmental health. She then volunteered at the UCI School of Medicine in the Air Pollution Health Effects Laboratory, where she participated in a cardiovascular project exploring the oxidative effects of particulate matter in ApoE -/- mice.

Julianne Yang

Julianne Yang

Graduate Student

Julianne is a PhD student in the Molecular, Cellular, and Integrative Physiology Program who began her adventures in the Jacobs Lab in January 2020. She completed a BS in biochemistry and a minor in chemistry from the University of Illinois at Urbana-Champaign, where she wrote her undergraduate thesis on how autism and epilepsy-linked mutations in potassium ion channels regulate their trafficking and membrane expression in neurons.

Matthew Zhao

Matthew Zhao

Medical Student

Matt received his BS in chemistry from New York University, where he completed an undergraduate thesis on the application of nucleic acid crystallography towards nano-scale organization of conductive polymers. He is currently studying a Crohn’s disease associated genetic variant and its effects on small intestinal microbiota and susceptibility to an experimental model of enteritis. His work is being supported by an NIDDK T32 Medical Student Research Training Supplement.

Lucy Balish

Lucy Balish

Undergraduate Student

Lucy is originally from Portland, Oregon, and is currently studying psychobiology. She plans to attend medical school after graduating from UCLA. Prompted not only by her curiosity to learn more about the human microbiome and the effects it has on the digestive system.

Anil Chaganti

Anil Chaganti

Undergraduate Student

Anil is from Simi Valley, California, 45 minutes north of UCLA. He joined the Jacobs Laboratory to gain experience in digestive diseases research and further understand the role of the gut microbiome in our bodies. After graduating, he plans to attend medical school.

Gianna Greco

Gianna Grecco

Undergraduate Student

Gianna is a second-year undergraduate student at UCLA studying physiological science. After graduating from UCLA, she hopes to attend medical school. She is originally from Ridgefield, CT, and in high school she did cell biology research using CRISPR to target the antibiotic resistance gene in bacteria. Outside of the lab, she is a sports nutrition intern at the Acosta Training Center.

Midori Hupfeld

Midori Hupfeld

Undergraduate Student

Midori is a fourth year physiological sciences major and global health minor from Carlsbad, California. She joined the Jacobs Laboratory interested in the relation between digestive health and the state of the human microbiome. After graduation, she plans to apply to medical school.

Grace Murphy

Grace Murphy

Undergraduate Student

Grace is a microbiology, immunology, and molecular genetics major with a minor in professional writing. She first became interested in the human gut microbiome during a physiological science course her freshman year. This initial interest led her to join the Jacobs Laboratory during her second year. Grace is specifically interested in the brain gut axis and how the gut microbiome impacts stress response.

Renga Rengappa

Renga Rengappa

Undergraduate Student

Renga is a second year UCLA undergraduate from San Jose, California, who is majoring in microbiology, immunology, and molecular genetics and minoring in biomedical research. Due to his personal experience with IBD, he chose to join Dr. Jacobs’ lab in order to learn more about the microbiome’s influence on regulating gut health. Renga plans to attend medical school and become a pediatric gastroenterologist.

Jelix Tsan

Jelix Tsan

Undergraduate Student

Jelix is from San Francisco, California, and is currently majoring in physiological sciences and minoring in applied developmental psychology. He joined the Jacobs lab to learn more about the microbiome and its significance to human physiology.