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Johan Heersche
Principal Investigator
Molecular Pharmacology/Endocrinology
Regulation of Cellular Activity and Differentiation of Bone Cells

My main interest is the regulation of differentiation and activity of bone forming cells (osteoblasts) and bone resorbing cells (osteoclasts).

The general aim is to gain insight in the causes of diseases such as osteoporosis, rheumatoid arthritis and atherosclerosis and work on the design of drugs specifically addressing certain aspects of these disease processes. Investigating bone loss as it occurs during space-flight is another aspect of the research program.

My research is supported by current grants from CIHR, the Arthritis Society, the Canadian Arthritis Network of Excellence, the Ontario Research and Development Challenge Fund, Industry and the Canadian Space Agency.


 

Osteoblast-focused projects are:

  • Investigating the regulation of osteoblast-differentiation by corticosteroids, sex steroids and insulin-like growth factors
  • Studying the effects of microgravity (space flight), mechanical unloading or loss of function on bone formation parameters
  • Analyzing the interaction between osteoblasts, osteoclasts and endothelial cells in the remodeling process
  • Studying functional differences between osteoblast populations in different anatomical sites

Osteoclast focused projects are:

  • Investigating the relationship between extracellular pH, intracellular pH and osteoclast activity
  • Studying the role of ανβ3 integrin signaling in osteoclast differentiation and fusion of osteoclast precursors
  • Evaluating osteoclast heterogeneity and its implications for drug design

Recent Publications

Ochotny NM, Van Vliet A, Chan N, Yao Y, Morel M, Kartner N, von Schroeder HP, Heersche JN, Manolson MF. Effects of human a3 and a4 mutations that result in osteopetrosis and distal renal tubular acidosis on yeast V-ATPase expression and activity. J Biol Chem. 2006, ePub. download

Basso N, Heersche JN. Effects of hind limb unloading and reloading on nitric oxide synthase expression and apoptosis of osteocytes and chondrocytes. Bone. 2006, ePub. download

Bellows CG, Jia D, Jia Y, Hassanloo A, Heersche JN. Different Effects of Insulin and Insulin-Like Growth Factors I and II on Osteoprogenitors and Adipocyte Progenitors in Fetal Rat Bone Cell Populations. Calcif Tissue Int. 2006 Jul;79(1):57-65. download

Basso N, Jia Y, Bellows CG, Heersche JN. The effect of reloading on bone volume, osteoblast number, and osteoprogenitor characteristics: studies in hind limb unloaded rats. Bone. 2005 Sep;37(3):370-8. download

Jia D, Heersche JN. Pregnancy-associated plasma protein-A proteolytic activity in rat vertebral cell cultures: stimulation by dexamethasone--a potential mechanism for glucocorticoid regulation of osteoprogenitor proliferation and differentiation. J Cell Physiol. 2005 Sep;204(3):848-58. download

Voronov I, Heersche JN, Casper RF, Tenenbaum HC, Manolson MF. Inhibition of osteoclast differentiation by polycyclic aryl hydrocarbons is dependent on cell density and RANKL concentration. Biochem Pharmacol. 2005 Jul 15;70(2):300-7. download

 

 

updated: March 2007, by Nick Basso