title: Characterization of calcium signaling pathways in human preadipocytes.
abstract: Intracellular free Ca2+ (Ca(i)2+) is an important regulator of many cellular activities; however, Ca2+ signaling is not well studied in human preadipocytes. The purpose of the present study was to characterize Ca2+ signal pathways using a confocal scanning technique and RT-PCR. It was found that spontaneous Ca(i)2+ oscillations were observed in 12.1% preadipocytes, and number of cells with Ca2+ oscillations was increased to 47.9% by 1% fetal bovine serum. Ca(i)2+ oscillations were dependent on Ca2+ entry mainly via stored-operated Ca2+ (SOC) entry. They were suppressed by the SOC entry channel blocker La3+, the phospholipase C (PLC) inhibitor U73122, the inositol trisphosphate receptor (IP3R) blocker 2-amino-ethoxydiphenyl borate, or the sarcoplasmic/endoplasmic reticulum Ca2+ pump (SERCA) inhibitors thapsigargin and cyclopiazonic acid, but not by ryanodine. The IP3R activator thimerosal increased Ca(i)2+ oscillations. In addition, the plasma membrane Ca2+ pump (PMCA) inhibitor carboxyeosin and Na+--Ca2+ exchanger (NCX) inhibitor Ni2+ both suppressed Ca2+ 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 Ca2+ signal pathways are present in human preadipocytes, and provides a basis for investigating how Ca2+ signals regulate biological and physiological activities of human preadipocytes.
authors.affiliation: Department of Medicine and Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Hu
authors.forename: Mu-Lan
authors.initials: ML
authors.lastname: He
authors.forename: Hao
authors.initials: H
authors.lastname: Hu
authors.forename: Bing-Xiang
authors.initials: BX
authors.lastname: Yuan
authors.forename: Wei-Jin
authors.initials: WJ
authors.lastname: Zang
authors.forename: Chu-Pak
authors.initials: CP
authors.lastname: Lau
authors.forename: Hung-Fat
authors.initials: HF
authors.lastname: Tse
authors.forename: Gui-Rong
authors.initials: GR
authors.lastname: Li
mesh_terms: D017667:Adipocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D009363:Neoplasm Proteins / Q000378:metabolism; D000071740:ORAI1 Protein; D053499:Plasma Membrane Calcium-Transporting ATPases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism; D019831:Sodium-Calcium Exchanger / Q000378:metabolism; D000071737:Stromal Interaction Molecule 1; D050052:TRPC Cation Channels / Q000378:metabolism; D013997:Time Factors; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D004791:Enzyme Inhibitors; D053496:Inositol 1,4,5-Trisphosphate Receptors; C419385:L-type calcium channel alpha(1C); D008565:Membrane Proteins; D009363:Neoplasm Proteins; D000071740:ORAI1 Protein; C510746:ORAI1 protein, human; D012333:RNA, Messenger; C101832:SLC38A3 protein, human; C103530:STIM1 protein, human; D019831:Sodium-Calcium Exchanger; D000071737:Stromal Interaction Molecule 1; D050052:TRPC Cation Channels; D010738:Type C Phospholipases; D053499:Plasma Membrane Calcium-Transporting ATPases; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; C506943:ATP2A1 protein, human