title: Mechanosensitive ATP release from hemichannels and Ca²⁺ influx through TRPC6 accelerate wound closure in keratinocytes.
abstract: Cutaneous wound healing is accelerated by exogenous mechanical forces and is impaired in TRPC6-knockout mice. Therefore, we designed experiments to determine how mechanical force and TRPC6 channels contribute to wound healing using HaCaT keratinocytes. HaCaT cells were pretreated with hyperforin, a major component of a traditional herbal medicine for wound healing and also a TRPC6 activator, and cultured in an elastic chamber. At 3 h after scratching the confluent cell layer, the ATP release and intracellular Ca(2+) increases in response to stretching (20%) were live-imaged. ATP release was observed only in cells at the frontier facing the scar. The diffusion of released ATP caused intercellular Ca(2+) waves that propagated towards the rear cells in a P2Y-receptor-dependent manner. The Ca(2+) response and wound healing were inhibited by ATP diphosphohydrolase apyrase, the P2Y antagonist suramin, the hemichannel blocker CBX and the TRPC6 inhibitor diC8-PIP2. Finally, the hemichannel-permeable dye calcein was taken up only by ATP-releasing cells. These results suggest that stretch-accelerated wound closure is due to the ATP release through mechanosensitive hemichannels from the foremost cells and the subsequent Ca(2+) waves mediated by P2Y and TRPC6 activation.
authors.affiliation: Department of Physiology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Nagoya, 466-8550, Japan.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Takada
authors.affiliation: Department of Physiology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Nagoya, 466-8550, Japan Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai, Nagoya, 466-8550, Japan furuya@med.nagoya-u.ac.jp.
authors.forename: Kishio
authors.initials: K
authors.lastname: Furuya
authors.affiliation: Department of Physiology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Nagoya, 466-8550, Japan Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai, Nagoya, 466-8550, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sokabe
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D002478:Cells, Cultured; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000378:metabolism*; D051379:Mice; D015398:Signal Transduction; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*; D000074287:TRPC6 Cation Channel
chemical_list: D050052:TRPC Cation Channels; D000074287:TRPC6 Cation Channel; C492146:Trpc6 protein, mouse; D000255:Adenosine Triphosphate; D002118:Calcium
keywords: ATP release; Ca2+ wave; HaCaT cells; Hemichannels; Mechanotransduction; Pannexin; TRPC6; Wound healing