Characterization of calcium signaling pathways in human preadipocytes

✍ Scribed by Rui Hu; Mu-lan He; Hao Hu; Bing-Xiang Yuan; Wei-Jin Zang; Chu-Pak Lau; Hung-Fat Tse; Gui-Rong Li

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 153 KB
• Volume: 220
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.21823

✦ Synopsis

Abstract

Intracellular free Ca^2+^ (Ca) is an important regulator of many cellular activities; however, Ca^2+^ signaling is not well studied in human preadipocytes. The purpose of the present study was to characterize Ca^2+^ signal pathways using a confocal scanning technique and RT‐PCR. It was found that spontaneous Ca oscillations were observed in 12.1% preadipocytes, and number of cells with Ca^2+^ oscillations was increased to 47.9% by 1% fetal bovine serum. Ca oscillations were dependent on Ca^2+^ entry mainly via stored‐operated Ca^2+^ (SOC) entry. They were suppressed by the SOC entry channel blocker La^3+^, the phospholipase C (PLC) inhibitor U73122, the inositol trisphosphate receptor (IP3R) blocker 2‐amino‐ethoxydiphenyl borate, or the sarcoplasmic/endoplasmic reticulum Ca^2+^ pump (SERCA) inhibitors thapsigargin and cyclopiazonic acid, but not by ryanodine. The IP3R activator thimerosal increased Ca oscillations. In addition, the plasma membrane Ca^2+^ pump (PMCA) inhibitor carboxyeosin and Na^+^–Ca^2+^ exchanger (NCX) inhibitor Ni^2+^ both suppressed Ca^2+^ oscillations. RT‐PCR revealed that the mRNAs for IP3R1‐3, SERCA1,2, NCX3 and PMCA1,3,4, Ca~V~1.2, and TRPC1,4,6, STIM1 and Orai1 (for SOC entry channels) were significant in human preadipocytes. The present study demonstrates that multiple Ca^2+^ signal pathways are present in human preadipocytes, and provides a basis for investigating how Ca^2+^ signals regulate biological and physiological activities of human preadipocytes. J. Cell. Physiol. 220: 765–770, 2009. © 2009 Wiley‐Liss, Inc.