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This Article Full Text Full Text (PDF) All Versions of this Article: 295/5/C1409    most recent 00268.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Tao, R. Articles by Li, G.-R. Search for Related Content PubMed PubMed Citation Articles by Tao, R. Articles by Li, G.-R.

GROWTH, DIFFERENTIATION, AND APOPTOSIS

Regulation of cell proliferation by intermediate-conductance Ca²⁺-activated potassium and volume-sensitive chloride channels in mouse mesenchymal stem cells

¹Department of Medicine, and Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, and ²Department of Physiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China

Submitted 22 May 2008 ; accepted in final form 16 September 2008

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 Ca²⁺-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 G₀/G₁ phase (control: 51.65 ± 3.43%) by inhibiting IK_Ca or I_Cl.vol using clotrimazole (2 µM: 64.45 ± 2.20%, P < 0.05) or NPPB (200 µM: 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.

intermediate conductance Ca²⁺-activated K⁺ current; volume sensitive Cl^– current; cell cycle progression; short interference RNA