title: Calcium-gated K+channels of the KCa1.1- and KCa3.1-type couple intracellular Ca2+signals to membrane hyperpolarization in mesenchymal stromal cells from the human adipose tissue.
abstract: Electrogenesis in mesenchymal stromal cells (MSCs) remains poorly understood. Little is known about ion channels active in resting MSCs and activated upon MSC stimulation, particularly, by agonists mobilizing Ca2+in the MSC cytoplasm. A variety of Ca2+-gated ion channels may couple Ca2+signals to polarization of the plasma membrane. Here, we studied MSCs from the human adipose tissue and found that in cells responsive to ATP and adenosine with Ca2+transients or exhibiting spontaneous Ca2+oscillations, Ca2+bursts were associated with hyperpolarization mediated by Ca2+-gated K+channels. The expression analysis revealed transcripts for KCNMA1 and KCNN4 genes encoding for Ca2+-activated K+channels of large (KCa1.1) and intermediate (KCa3.1) conductance, respectively. Moreover, transcripts for the Ca2+-gated cation channel TRPM4 and anion channels Ano1, Ano2, and bestrophin-1, bestrophin-3, and bestrophin-4 were revealed. In all assayed MSCs, a rise in cytosolic Ca2+stimulated K+currents that were inhibited with iberiotoxin. This suggested that KCa1.1 channels are invariably expressed in MSCs. In ATP- and adenosine-responsive cells, iberiotoxin and TRAM-34 diminished electrical responses, implicating both KCa1.1 and KCa3.1 channels in coupling agonist-dependent Ca2+signals to membrane voltage. Functional tests pointed at the existence of two separate MSC subpopulations exhibiting Ca2+-gated anion currents that were mediated by Ano2-like and bestrophin-like anion channels, respectively. Evidence for detectable activity of Ano1 and TRPM4 was not obtained. Thus, KCa1.1 channels are likely to represent the dominant type of Ca2+-activated K+channels in MSCs, which can serve in concert with KCa3.1 channels as effectors downstream of G-protein-coupled receptor (GPCR)-mediated Ca2+signaling.
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, Institutional Street 3, Pushchino, Moscow Region, Russia, 142290.
authors.forename: Michail V
authors.initials: MV
authors.lastname: Tarasov
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, Institutional Street 3, Pushchino, Moscow Region, Russia, 142290.
authors.forename: Marina F
authors.initials: MF
authors.lastname: Bystrova
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, Institutional Street 3, Pushchino, Moscow Region, Russia, 142290.
authors.forename: Polina D
authors.initials: PD
authors.lastname: Kotova
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, Institutional Street 3, Pushchino, Moscow Region, Russia, 142290.
authors.forename: Olga A
authors.initials: OA
authors.lastname: Rogachevskaja
authors.affiliation: Department of Biochemistry and Molecular Medicine, Faculty of Basic Medicine, Lomonosov Moscow State University, Moscow, Russia.
authors.forename: Veronika Y
authors.initials: VY
authors.lastname: Sysoeva
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, Institutional Street 3, Pushchino, Moscow Region, Russia, 142290. staskolesnikov@yahoo.com.
authors.forename: Stanislav S
authors.initials: SS
authors.lastname: Kolesnikov
mesh_terms: D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000328:Adult; D000075369:Anoctamin-1; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D018118:Chloride Channels / Q000378:metabolism; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism*; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits / Q000378:metabolism*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000378:metabolism*; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology
chemical_list: C476213:ANO1 protein, human; D000075369:Anoctamin-1; D018118:Chloride Channels; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels; C494841:KCNMA1 protein, human; C496923:KCNN4 protein, human; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D009363:Neoplasm Proteins; D026902:Potassium Channel Blockers; D011720:Pyrazoles; C411671:TRAM 34; D011188:Potassium; D002118:Calcium
keywords: ATP; Adenosine; Ca2+ imaging; Ca2+-activated K+ channels; Mesenchymal stromal cells; Patch clamp