John S.D. Chan, PhD
Professor of Medicine and Physiology
Biographical Sketch
John Chan was trained in Physiology and Biochemistry at the
University of Manitoba, where he obtained a PhD degree under the supervision of
Dr Henry G. Friesen. His thesis was in the field of Endocrinology. He then worked as
a post-doctoral fellow on �Biosynthesis and secretion of pro-opiomelanocortin in
human pituitary� in the laboratory of Dr Michel Chr�tien at the Institut de Recherches
Cliniques de Montr�al and the laboratory of Dr Dorothy Krieger (deceased) of Mount
Sinai Medical Centre, New York, NY. He then returned to Montreal and worked at the
Institut de Recherches Cliniques de Montr�al as a Research Associate and then promoted
as a Research Assistant Professor in the Department of Physiology, University of
Montreal. He later worked as a Visiting Scientist and Visiting Assistant Professor
at the National Institutes of Health (NIH) of USA and Harvard Medical School,
respectively. Finally, he returned back to Montreal and worked as a Director of the
laboratory of Molecular Nephrology and Endocrinology, Research Centre, Maisonneuve
Rosemont Hospital of Montreal.
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Selected Scientific Contributions
As an independent investigator, Dr Chan demonstrated the presence
of renin-angiotensin system in the kidney. He showed the expression of angiotensinogen
(the sole precursor of the RAS) gene is under the regulation of catecholamines
(sympathetic nervous system), implicating that intrarenal RAS activation may play an
important role in hypertension development.
More recently, Dr Chan demonstrated that high glucose regulates
angiotensinogen gene expression in the kidney via reactive oxygen species generation.
By employing transgenic mouse models, Dr Chan�s group demonstrated unequivocally that
overexpression of angiotensinogen specifically in the kidney induces hypertension,
albuminuria and kidney injury. In contrast, overexpression of catalase specifically
in the kidney attenuates RAS activation, hypertension, albuminuria and kidney cell
apoptosis in diabetes.
Finally, in collaboration with the groups of Dr Catharine
Whiteside and Dr George I. Fantus, Dr Chan has identified several genes that are
differentially up-regulated in diabetic kidneys and they might play an important role
in tubular apoptosis and atrophy in diabetes.
Click here for PubMed listing
Research Interests
The role of intrarenal RAS and ROS in the pathogenesis of diabetic
nephropathy, with special emphasis on renal angiotensinogen gene expression and
intrarenal ROS generation on tubular apoptosis in diabetes. Transgenic mice
specifically overexpressing angiotensinogen and catalase in the kidney will be used
to study the molecular mechanism(s) of intrarenal RAS and ROS action on the induction
of tubular fibrosis and apoptosis in diabetes. Gene chip microarrays will be used to
identify the unique genes that are differentially expressed in diabetic kidneys. The
physiological role(s) of these unique genes will be studied in vitro and
in vivo.
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