title: Shear stress-induced Ca²⁺ mobilization in MDCK cells is ATP dependent, no matter the primary cilium.
abstract: Primary cilium has emerged as mechanosensor to subtle flow variations in epithelial cells, but its role in shear stress detection remains controversial. To probe the function of this non-motile organelle in shear stress detection by cells, we compared calcium signalling responses induced by shear stress in ciliated and unciliated MDCK cells. Cytosolic free Ca²⁺ ([Ca²⁺]i) was measured using Fura-PE3 video imaging fluorescence microscopy in response to shear stress due to laminar flow (385 μl s⁻¹). Our results show that both unciliated and ciliated MDCK cells are shear stress sensitive via ATP release and autocrine feedback through purinergic receptors. However, purinergic calcium signals differed in response intensity and receptor subtypes. In unciliated cells, shear stress-induced elevation in [Ca²⁺]i was predominantly mediated through P2X receptors (P2XR). In contrast, calcium mobilization in ciliated MDCK cells resulted from P2YRs and store-operated Ca²⁺-permeable channels besides P2XRs. These findings lend support to the hypothesis that ATP release in response to shear stress is independent of the primary cilium and that transduction of mechanical strain into a specific biochemical responses stems on the mobilization of different sets of purinergic receptors.
authors.affiliation: Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, UMR 7286, CNRS, Université AIX-MARSEILLE, CS80011 Bd Pierre Dramard, 13344 Marseille Cedex 15, France. lise.despoix@gmail.com
authors.forename: Lise
authors.initials: L
authors.lastname: Rodat-Despoix
authors.forename: Jizhe
authors.initials: J
authors.lastname: Hao
authors.forename: Mathieu
authors.initials: M
authors.lastname: Dandonneau
authors.forename: Patrick
authors.initials: P
authors.lastname: Delmas
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D019898:Autocrine Communication; D020013:Calcium Signaling; D002923:Cilia / Q000502:physiology*; D004285:Dogs; D025461:Feedback, Physiological; D061985:Madin Darby Canine Kidney Cells; D040542:Mechanotransduction, Cellular; D008856:Microscopy, Fluorescence; D009928:Organ Specificity; D061251:Primary Cell Culture; D058469:Receptors, Purinergic P2X / Q000378:metabolism*; D058470:Receptors, Purinergic P2Y / Q000378:metabolism*; D033081:Shear Strength; D013314:Stress, Mechanical
chemical_list: D058469:Receptors, Purinergic P2X; D058470:Receptors, Purinergic P2Y; D000255:Adenosine Triphosphate