title: A PLCγ1-dependent, force-sensitive signaling network in the myogenic constriction of cerebral arteries.
abstract: Maintaining constant blood flow in the face of fluctuations in blood pressure is a critical autoregulatory feature of cerebral arteries. An increase in pressure within the artery lumen causes the vessel to constrict through depolarization and contraction of the encircling smooth muscle cells. This pressure-sensing mechanism involves activation of two types of transient receptor potential (TRP) channels: TRPC6 and TRPM4. We provide evidence that the activation of the γ1 isoform of phospholipase C (PLCγ1) is critical for pressure sensing in cerebral arteries. Inositol 1,4,5-trisphosphate (IP3), generated by PLCγ1 in response to pressure, sensitized IP3 receptors (IP3Rs) to Ca(2+) influx mediated by the mechanosensitive TRPC6 channel, synergistically increasing IP3R-mediated Ca(2+) release to activate TRPM4 currents, leading to smooth muscle depolarization and constriction of isolated cerebral arteries. Proximity ligation assays demonstrated colocalization of PLCγ1 and TRPC6 with TRPM4, suggesting the presence of a force-sensitive, local signaling network comprising PLCγ1, TRPC6, TRPM4, and IP3Rs. Src tyrosine kinase activity was necessary for stretch-induced TRPM4 activation and myogenic constriction, consistent with the ability of Src to activate PLCγ isoforms. We conclude that contraction of cerebral artery smooth muscle cells requires the integration of pressure-sensing signaling pathways and their convergence on IP3Rs, which mediate localized Ca(2+)-dependent depolarization through the activation of TRPM4.
authors.affiliation: Vascular Physiology Research Group, Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA. Department of Pharmacology, University of Vermont, Burlington, VT 05405, USA.
authors.forename: Albert L
authors.initials: AL
authors.lastname: Gonzales
authors.affiliation: Vascular Physiology Research Group, Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Vascular Physiology Research Group, Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Michelle N
authors.initials: MN
authors.lastname: Sullivan
authors.affiliation: Vascular Physiology Research Group, Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Lindsey
authors.initials: L
authors.lastname: Sanders
authors.affiliation: Department of Pharmacology, University of Vermont, Burlington, VT 05405, USA.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Dabertrand
authors.affiliation: Department of Pharmacology, University of Vermont, Burlington, VT 05405, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Hill-Eubanks
authors.affiliation: Department of Pharmacology, University of Vermont, Burlington, VT 05405, USA. Institute of Cardiovascular Sciences, University of Manchester, Manchester M13 9NT, UK.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Nelson
authors.affiliation: Department of Pharmacology, University of Nevada School of Medicine, Reno, NV 89557-0318, USA. searley@medicine.nevada.edu.
authors.forename: Scott
authors.initials: S
authors.lastname: Earley
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D002536:Cerebral Arteries / Q000502:physiology*; D057809:HEK293 Cells; D006801:Humans; D007150:Immunohistochemistry; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D018408:Patch-Clamp Techniques; D051966:Phospholipase C gamma / Q000378:metabolism*; D034622:RNA Interference; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D050052:TRPC Cation Channels / Q000378:metabolism; D000074287:TRPC6 Cation Channel; D050053:TRPM Cation Channels / Q000378:metabolism*; D014661:Vasoconstriction / Q000502:physiology*; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D053496:Inositol 1,4,5-Trisphosphate Receptors; D050052:TRPC Cation Channels; D000074287:TRPC6 Cation Channel; C117032:TRPC6 protein, human; D050053:TRPM Cation Channels; C437888:TRPM4 protein, human; D019061:src-Family Kinases; C522157:PLCG1 protein, human; D051966:Phospholipase C gamma