Joseph Dhahbi MD, PhD

Joseph Dhahbi

Contact Information

Faculty Appointment

Professor of Biochemistry, Genomics and Medical Education

Administrative Appointments

Director of Academic Research Study


Dr. Dhahbi earned an M.D degree from the University of Tunis – School of Medicine, completed a residency program, and practiced medicine for several years in his native country, Tunisia. He moved to the United States, and joined the department of Biochemistry at the University of California Riverside where he earned a Ph.D degree in Molecular Genetics.


Dr. Dhahbi is a Professor of Biochemistry, Genomics and Medical Education at CalMed. He previously taught Biochemistry, genetics and Genomics at California Northstate University, School of Medicine, and the University California, Riverside. Dr. Dhahbi also served as a clinical Fellow at Children’s Hospital Oakland Research Institute supported by a grant from the California Institute for Regenerative Medicine (CIRM), as a Senior Research Scientist at Lifespan Genetics Research, and as a Director of Research at BioMarker Pharmaceuticals, Campbell, California.

Research Description

Dr. Dhahbi's current research focuses on characterizing new classes of extracellular small RNAs using next generation sequencing to show how tRNA- and YRNA-derived small RNAs function in cell-to-cell communication. He has found that serum levels of specific types of 5’ tRNA halves and YRNA-derived small RNAs change with cancer and aging and may be novel immune system signaling molecules. He is using various approaches to identify the factors/proteins that bind to serum tRNA- and YRNA-derived small RNAs, their biogenesis, distribution, uptake and function in peripheral tissues. His goals are to establish these new serum/plasma small RNAs as signaling molecules, and develop them as therapeutic targets and noninvasive diagnostic biomarkers of cancer and other diseases. He currently has ongoing collaborations on different research projects with David Martin at Children's Hospital Oakland Research Institute, Steve Spindler at University of California Riverside, and Michal Masternak at the University of Central Florida, Augusto Schneider at The Federal University of Pelotas in Brazil, and Luke Selth at Adelaide Medical School in Australia.

Dr. Dhahbi's previous research included the use of GeneChip technology to investigate the effects of calorie restriction, drugs and nutraceuticals on the patterns of gene expression associated with aging. He also participated in the development of a program in biomarker discovery to screen interventions that mimic the beneficial healthful effects of calorie restriction; this work led to the awarding of a patent for screening for biomarkers of health and longevity. While at Children's Hospital Oakland Research Institute, he conducted epigenetics research to investigate epigenetic disruptors that could reverse developmental silencing of globin genes, which could become candidate small molecule therapeutics for Sickle Cell Disease and ß-thalassemia. His post-doctoral research at the Jerry L. Pettis Memorial Veterans Hospital, Loma Linda, California, focused on the development of techniques using hematopoietic stem cells for systemic gene therapy targeting bone diseases.

Dr. Dhahbi has extensive experience in statistical and bioinformatic analyses of genomic data generated by both microarray and next-generation sequencing platforms.