title: Mechanosensitive Ca²⁺-permeable channels in human leukemic cells: pharmacological and molecular evidence for TRPV2.
abstract: Mechanosensitive channels are present in almost every living cell, yet the evidence for their functional presence in T lymphocytes is absent. In this study, by means of the patch-clamp technique in attached and inside-out modes, we have characterized cationic channels, rapidly activated by membrane stretch in Jurkat T lymphoblasts. The half-activation was achieved at a negative pressure of ~50mm Hg. In attached mode, single channel currents displayed an inward rectification and the unitary conductance of ~40 pS at zero command voltage. In excised inside-out patches the rectification was transformed to an outward one. Mechanosensitive channels weakly discriminated between mono- and divalent cations (PCa/PNa~1) and were equally permeable for Ca²⁺ and Mg²⁺. Pharmacological analysis showed that the mechanosensitive channels were potently blocked by amiloride (1mM) and Gd³⁺ (10 μM) in a voltage-dependent manner. They were also almost completely blocked by ruthenium red (1 μM) and SKF 96365 (250 μM), inhibitors of transient receptor potential vanilloid 2 (TRPV2) channels. At the same time, the channels were insensitive to 2-aminoethoxydiphenyl borate (2-APB, 100 μM) or N-(p-amylcinnamoyl)anthranilic acid (ACA, 50 μM), antagonists of transient receptor potential canonical (TRPC) or transient receptor potential melastatin (TRPM) channels, respectively. Human TRPV2 siRNA virtually abolished the stretch-activated current. TRPV2 are channels with multifaceted functions and regulatory mechanisms, with potentially important roles in the lymphocyte Ca²⁺ signaling. Implications of their regulation by mechanical stress are discussed in the context of lymphoid cells functions.
authors.affiliation: Center for Biomedical Research, University of Colima, Colima, Mexico.
authors.forename: Igor
authors.initials: I
authors.lastname: Pottosin
authors.affiliation: School of Medicine, University of Colima, Colima, Mexico.
authors.forename: Iván
authors.initials: I
authors.lastname: Delgado-Enciso
authors.affiliation: Center for Biomedical Research, University of Colima, Colima, Mexico.
authors.forename: Edgar
authors.initials: E
authors.lastname: Bonales-Alatorre
authors.affiliation: Center for Biomedical Research, University of Colima, Colima, Mexico.
authors.forename: María G
authors.initials: MG
authors.lastname: Nieto-Pescador
authors.affiliation: Center for Biomedical Research, University of Colima, Colima, Mexico.
authors.forename: Eloy G
authors.initials: EG
authors.lastname: Moreno-Galindo
authors.affiliation: Center for Biomedical Research, University of Colima, Colima, Mexico. Electronic address: oxana@ucol.mx.
authors.forename: Oxana
authors.initials: O
authors.lastname: Dobrovinskaya
mesh_terms: D000584:Amiloride / Q000494:pharmacology; D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D015640:Ion Channel Gating / Q000502:physiology*; D017136:Ion Transport / Q000187:drug effects / Q000502:physiology; D019169:Jurkat Cells; D015458:Leukemia, T-Cell / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D008274:Magnesium / Q000378:metabolism; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D008564:Membrane Potentials / Q000235:genetics / Q000502:physiology; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012430:Ruthenium Red / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D050916:TRPV Cation Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001896:Boron Compounds; D007093:Imidazoles; D050916:TRPV Cation Channels; C400769:TRPV2 protein, human; D012430:Ruthenium Red; D000584:Amiloride; D012964:Sodium; C109986:2-aminoethoxydiphenyl borate; D008274:Magnesium; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole; D011188:Potassium; D002118:Calcium
keywords: Calcium; Mechanosensitive channel; Plasma membrane stretch; T-lymphocyte; TRPV2