X L Deng1, C P Lau, K Lai, K F Cheung, G K Lau, G R Li. 1. Department of Medicine, and Research Centre of Heart, Brain, Hormone and Healthy Ageing, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong.
Abstract
OBJECTIVE: Recently, our team has demonstrated that voltage-gated delayed rectifier K(+) current (IK(DR)) and Ca(2+)-activated K(+) current (I(KCa)) are present in rat bone marrow-derived mesenchymal stem cells; however, little is known of their physiological roles. The present study was designed to investigate whether functional expression of IK(DR) and I(KCa) would change with cell cycle progression, and whether they could regulate proliferation in undifferentiated rat mesenchymal stem cells (MSCs). MATERIALS AND METHODS: Membrane potentials and ionic currents were recorded using whole-cell patch clamp technique, cell cycling was analysed by flow cytometry, cell proliferation was assayed with DNA incorporation method and the related genes were down-regulated by RNA interference (RNAi) and examined using RT-PCR. RESULTS: It was found that membrane potential hyperpolarized, and cell size increased during the cell cycle. In addition, IK(DR) decreased, while I(KCa) increased during progress from G(1) to S phase. RT-PCR revealed that the mRNA levels of Kv1.2 and Kv2.1 (likely responsible for IK(DR)) reduced, whereas the mRNA level of KCa3.1 (responsible for intermediate-conductance I(KCa)) increased with the cell cycle progression. Down-regulation of Kv1.2, Kv2.1 or KCa3.1 with the specific RNAi, targeted to corresponding gene inhibited proliferation of rat MSCs. CONCLUSION: These results demonstrate that membrane potential, IK(DR) and I(KCa) channels change with cell cycle progression and corresponding alteration of gene expression. IK(DR) and intermediate-conductance I(KCa) play an important role in maintaining membrane potential and they participate in modulation of proliferation in rat MSCs.
OBJECTIVE: Recently, our team has demonstrated that voltage-gated delayed rectifier K(+) current (IK(DR)) and Ca(2+)-activated K(+) current (I(KCa)) are present in rat bone marrow-derived mesenchymal stem cells; however, little is known of their physiological roles. The present study was designed to investigate whether functional expression of IK(DR) and I(KCa) would change with cell cycle progression, and whether they could regulate proliferation in undifferentiated rat mesenchymal stem cells (MSCs). MATERIALS AND METHODS: Membrane potentials and ionic currents were recorded using whole-cell patch clamp technique, cell cycling was analysed by flow cytometry, cell proliferation was assayed with DNA incorporation method and the related genes were down-regulated by RNA interference (RNAi) and examined using RT-PCR. RESULTS: It was found that membrane potential hyperpolarized, and cell size increased during the cell cycle. In addition, IK(DR) decreased, while I(KCa) increased during progress from G(1) to S phase. RT-PCR revealed that the mRNA levels of Kv1.2 and Kv2.1 (likely responsible for IK(DR)) reduced, whereas the mRNA level of KCa3.1 (responsible for intermediate-conductance I(KCa)) increased with the cell cycle progression. Down-regulation of Kv1.2, Kv2.1 or KCa3.1 with the specific RNAi, targeted to corresponding gene inhibited proliferation of rat MSCs. CONCLUSION: These results demonstrate that membrane potential, IK(DR) and I(KCa) channels change with cell cycle progression and corresponding alteration of gene expression. IK(DR) and intermediate-conductance I(KCa) play an important role in maintaining membrane potential and they participate in modulation of proliferation in rat MSCs.
Authors: Yuehua Jiang; Balkrishna N Jahagirdar; R Lee Reinhardt; Robert E Schwartz; C Dirk Keene; Xilma R Ortiz-Gonzalez; Morayma Reyes; Todd Lenvik; Troy Lund; Mark Blackstad; Jingbo Du; Sara Aldrich; Aaron Lisberg; Walter C Low; David A Largaespada; Catherine M Verfaillie Journal: Nature Date: 2002-06-20 Impact factor: 49.962
Authors: Aguan D Wei; George A Gutman; Richard Aldrich; K George Chandy; Stephan Grissmer; Heike Wulff Journal: Pharmacol Rev Date: 2005-12 Impact factor: 25.468
Authors: Amal K Dutta; Al-karim Khimji; Meghana Sathe; Charles Kresge; Vinay Parameswara; Victoria Esser; Don C Rockey; Andrew P Feranchak Journal: Am J Physiol Gastrointest Liver Physiol Date: 2009-11 Impact factor: 4.052
Authors: Neil C Henney; Bo Li; Carole Elford; Pablo Reviriego; Anthony K Campbell; Kenneth T Wann; Bronwen A J Evans Journal: Am J Physiol Cell Physiol Date: 2009-09-23 Impact factor: 4.249