Endocrinologist who opened up a whole new branch of biology by discovering convertases, enzymes that cleave proteins to create biologically active chemicals such as hormones
"The pursuit of biomedical research demands exceptional intellectual rigour that nevertheless gives rein to wisdom, perception, and logic. It is a necessity that constantly meets up with felicitous strokes of luck and large doses of serendipity."
Chretien's life work began while he was a doctoral student at Berkeley in the 1960s. His seminal paper, published in the Canadian Journal of Biochemistry in 1967, pointed out patterns in the cleavage sites in precursors of many of the specialized molecules the body needs to function. He suggested the existence of convertases, which are enzymes that split large proteins into the crucial chemicals of life, such as insulin, endorphins and growth factors. An understanding of these enzymes forms not only a basis to fundamental metabolic processes, but suggests new insights into natural processes such as aging, and the pathologies of cancer, atherosclerosis, hypertension, obesity, epilepsy, psoriasis and AIDS.
The next step was to find the enzymes that act as convertases. Starting in 1967, as Director and later as Scientific Director, Chretien led a team at the Biochemical Neuroendocrinology laboratory of the Clinical Research Institute of Montreal (CRIM) in this endeavor. He was joined by Dr. Nabil G. Seidah in 1974. It was not until 1990 that a new technology allowed the team to actually discover convertases. PCR, or polymer chain reaction, is a means whereby DNA molecules can be synthesized and amplified using known strings of amino acids. Using this technology, the team was able to identify the characteristics of seven of the eight mammalian convertases known thus far.
Image by: Freelance Illustration
Under Chretien's scientific directorship, the research facilities at CRIM expanded rapidly, growing to include research programs in molecular biology, molecular genetics, immunology, neurobiology, and brain chemistry. His studies on convertases ranged widely, including topics such as their effects on tumours and their role in brain development in the unborn child.
In 1998, Chretien joined the Ottawa Civic Hospital Loeb Research Institute as CEO and scientific director. There he founded the Diseases of Aging Centre, where he continues his collaborations with his colleagues from CRIM. At present, he is applying his knowledge of convertases to an investigation of diseases that accelerate the aging process, such as diabetes, obesity, AIDS and Alzheimer's.
Dr. Chretien is the recipient of many degrees and honours for his pioneering research.
Profile viewed 27722 times