Oscillatory shear stress induced calcium flickers in osteoblast cells.
The dynamic physical microenvironment of bone affects the activity of osteoblast cells, yet little is known about how osteoblast mechanotransduction depends on different features of a dynamic stimulus. Here we investigated the effect of physiologically relevant oscillatory flow shear stress on the calcium mobility in osteoblast cells within a microfluidic platform that mimics the confined environment of bone matrix. We characterized the spatiotemporal evolution of intracellular calcium 'flickers', an important signature of cell activation, in response to steady, pulsatile, and oscillatory shear stress. We found that oscillatory flow induces surprisingly higher flicker activity than other flow types. We could further attribute this phenomenon to the opening of a stretch activated ion channel, namely TRPM7. We also found that localization of TRPM7 within the cholesterol-enriched lipid raft domains of plasma membranes is essential for its activity. Collectively our findings elucidated a candidate mechanism for the flow mediated stimulation of osteoblast cells. They therefore have implications towards unveiling various facets of bone formation and remodelling in healthy and diseased conditions, including bone-metastasis of various cancer types, diabetes, and inflammatory autoimmune diseases.
Department of Biotechnology, Indian Institute for Technology Kharagpur, Kharagpur - 721302, India.
Bibhas
B
Roy
Tamal
T
Das
Debasish
D
Mishra
Tapas K
TK
Maiti
Suman
S
Chakraborty
D001857:Bone Matrix / Q000166:cytology / Q000378:metabolism; D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002460:Cell Line; D060833:Cellular Microenvironment; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D005682:Gadolinium / Q000494:pharmacology; D055785:Gene Knockdown Techniques; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism; D040542:Mechanotransduction, Cellular; D021962:Membrane Microdomains / Q000378:metabolism; D046210:Microfluidic Analytical Techniques; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D011760:Pyrrolidinones / Q000494:pharmacology; D013314:Stress, Mechanical; D050053:TRPM Cation Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019284:Thapsigargin / Q000494:pharmacology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors; D014700:Verapamil / Q000494:pharmacology
D001896:Boron Compounds; D002121:Calcium Channel Blockers; D004791:Enzyme Inhibitors; D004963:Estrenes; D007473:Ion Channels; D011760:Pyrrolidinones; D050053:TRPM Cation Channels; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D019284:Thapsigargin; D005682:Gadolinium; D014700:Verapamil; C109986:2-aminoethoxydiphenyl borate; D017346:Protein Serine-Threonine Kinases; C486583:TRPM7 protein, human; D010738:Type C Phospholipases; D000252:Calcium-Transporting ATPases; D002118:Calcium