Involvement of volume-sensitive Cl- channels in the proliferation of human subcutaneous pre-adipocytes

1. Obesity is a significant challenge in terms of public health and preventive medicine. Inhibition of pre-adipocyte proliferation is believed to be important in the proposed anti-obesity mechanism. The aim of the present study was to examine the interplay between Cl(-) channels and their possible involvement in the proliferation of undifferentiated human pre-adipocytes. 2. Pre-adipocytes were isolated from human abdominal subcutaneous adipose tissue. Membrane ion currents were recorded using the whole-cell patch-clamp technique. Expression of the Cl(-) channel ClC-3 gene and protein was determined by reverse transcription-polymerase chain reaction (RT-PCR) and western blot, respectively. Cell proliferation was evaluated using the [(3)H]-thymidine incorporation assay. 3. Electrophysiological recordings revealed a volume-sensitive Cl(-) current (I(Cl.vol)) expressed in pre-adipocytes that was activated under hyposmotic conditions (external osmolarity decreased by 80%) and inhibited by the Cl(-) channel blocker tamoxifen. 4. Expression of the ClC-3 channel gene and protein was confirmed by RT-PCR and western blot analysis. Blocking I(Cl.vol) with tamoxifen supressed the proliferation of pre-adipocytes in a concentration-dependent manner. 5. Collectively, the results of the present study indicate that the volume-sensitive Cl(-) channel participates in regulation of the proliferation of human subcutaneous pre-adipocytes.