Jacques J. Tremblay, MSc, PhD, LLB

Dr. Tremblay’s research program is at the interface of developmental biology, endocrinology, and cellular and molecular biology. His team studies the molecular mechanisms of male sexual differentiation. Mutations in key genes involved in male sexual differentiation are responsible for an atypical developmental trajectory known as Differences in Sex Development (DSD).

Dr. Tremblay’s team is studying new genes that could help explain certain cases of DSD in humans. In addition, Dr. Tremblay is interested in the differentiation and function of Leydig cells, endocrine cells that produce the steroid hormone testosterone. Inadequate levels of steroid hormones are implicated in many human pathologies, including cancers, PCOS, endometriosis, autoimmune diseases and inflammation. As well as being important for male reproductive health, adequate levels of testosterone are also essential for men’s general health. Understanding how this system functions normally, by studying Leydig cells, will provide essential information that will ultimately enable better diagnosis and treatment of these pathologies.

Although various hormones and signaling molecules have been implicated in male sexual differentiation and Leydig cell differentiation and function, the transcription factors downstream of these pathways remain poorly understood. To date, his team has identified several transcription factors, some never before reported in the gonad or Leydig cells. Some are present exclusively in the male gonad, or at specific times in Leydig cells, while others mark stem Leydig cells. A better understanding of the differentiation of stem Leydig cells residing in the adult testis could enable the development of innovative treatments for men suffering from hypogonadism.

In addition, their work on hormone-induced signaling pathways in Leydig cells has revealed the involvement of two antagonistic kinases; CAMKI stimulates while AMPK is a molecular brake that rapidly shuts down steroid hormone production, which has many clinical implications. Dr. Tremblay’s work involves classical molecular and cell biology, gene editing, animal models, microscopy, proteomics, transcriptomics and bioinformatics.

Laurie Boudreau, BSc
MSc student
laurie.boudreau.3@ulaval.ca

Karine de Mattos, DMV, MSc
PhD student
karine.de-mattos.1@ulaval.ca

Kenley Joule Pierre, MSc
PhD student
kenley-joule.pierre.1@ulaval.ca

Nicholas M. Robert, PhD
Research assistant
Nicholas.Robert@crchudequebec.ulaval.ca