Date:

2025-04-30

Title of Paper:

Characterization of ion channels in human preadipocytes

Journal:

J Cell Physiol

Summary:

Ion channels participate in regulation of cell proliferation. However, though preadipocyte (the progenitor of fat cell) is a type of highly proliferating cells, ion channel expression and their role in proliferation is not understood in human preadipocytes. The present study was designed to characterize ion channels using whole-cell patch clamp technique, RT-PCR, and Western blotting. It was found that a 4-aminopyridine- (4-AP) sensitive transient outward K+ current (Ito) was present in a small population of (32.0%) cells, and an outward noisy big conductance Ca2+-activated K+ current (IKCa) was present in most (92.7%) preadipocytes. The noisy current was inhibited by the big conductance IKCa channel blocker paxilline (1 µM), and enhanced by the Ca2+ ionophore A23187 (5 µM) and the big conductance IKCa channel activator NS1619 (10 µM). RT-PCR and Western blot revealed the molecular identities (i.e., KCa1.1 and Kv4.2) of the functional ionic currents IKCa and Ito. Blockade of IKCa or Ito with paxilline or 4-AP reduced preadipocyte proliferation, and similar results were obtained with specific siRNAs targeting to KCa1.1 and Kv4.2. Flow cytometric analysis showed ion channel blockade or knockdown of KCa1.1 or Kv4.2 with specific siRNA increased the cell number of G0/G1 phase. The present study demonstrates for the first time that two types of functional ion channel currents, Ito and big conductance IKCa, are present in human preadipocytes and that these two types of ion channels participate in regulating proliferation of human preadipocytes.

Co-author:

Hu H, He ML, Tao R, Sun HY, Hu R, Zang WJ

Volume:

218(2)

Page Number:

427-435

Translation or Not:

No

Date of Publication:

2009-02-10