title: Regulation of cell proliferation by intermediate-conductance Ca2+-activated potassium and volume-sensitive chloride channels in mouse mesenchymal stem cells.
abstract: Bone marrow mesenchymal stem cells (MSCs) are a promising cell source for regenerative medicine; however, their cellular physiology is not fully understood. The present study aimed at exploring the potential roles of the two dominant functional ion channels, intermediate-conductance Ca(2+)-activated potassium (IK(Ca)) and volume-sensitive chloride (I(Cl.vol)) channels, in regulating proliferation of mouse MSCs. We found that inhibition of IK(Ca) with clotrimazole and I(Cl.vol) with 5-nitro-1-(3-phenylpropylamino) benzoic acid (NPPB) reduced cell proliferation in a concentration-dependent manner. Knockdown of KCa3.1 or Clcn3 with specific short interference (si)RNAs significantly reduced IK(Ca) or I(Cl.vol) density and channel protein and produced a remarkable suppression of cell proliferation (by 24.4 +/- 9.6% and 29.5 +/- 7.2%, respectively, P < 0.05 vs. controls). Flow cytometry analysis showed that mouse MSCs retained at G(0)/G(1) phase (control: 51.65 +/- 3.43%) by inhibiting IK(Ca) or I(Cl.vol) using clotrimazole (2 microM: 64.45 +/- 2.20%, P < 0.05) or NPPB (200 microM: 82.89 +/- 2.49%, P < 0.05) or the specific siRNAs, meanwhile distribution of cells in S phase was decreased. Western blot analysis revealed a reduced expression of the cell cycle regulatory proteins cyclin D1 and cyclin E. Collectively, our results have demonstrated that IK(Ca) and I(Cl.vol) channels regulate cell cycle progression and proliferation of mouse MSCs by modulating cyclin D1 and cyclin E expression.
authors.affiliation: Dept. of Medicine, L8-01, Laboratory Block, FMB, The Univ. of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong SAR China.
authors.forename: Rong
authors.initials: R
authors.lastname: Tao
authors.forename: Chu-Pak
authors.initials: CP
authors.lastname: Lau
authors.forename: Hung-Fat
authors.initials: HF
authors.lastname: Tse
authors.forename: Gui-Rong
authors.initials: GR
authors.lastname: Li
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D048429:Cell Size; D002478:Cells, Cultured; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003022:Clotrimazole / Q000494:pharmacology; D019938:Cyclin D1 / Q000378:metabolism; D019927:Cyclin E / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008564:Membrane Potentials; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009579:Nitrobenzoates / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism
chemical_list: C530105:Ccnd1 protein, mouse; D018118:Chloride Channels; C115376:ClC-3 channel; D019927:Cyclin E; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels; C496925:Kcnn4 protein, mouse; D009579:Nitrobenzoates; D026902:Potassium Channel Blockers; D034741:RNA, Small Interfering; D019938:Cyclin D1; D003022:Clotrimazole