摘要
AIM:To investigate serotonergic Ca 2+ signaling and the expression of 5-hydroxytryptamine(5-HT) receptors,as well as Ca 2+ transporting proteins,in hepatic stellate cells(HSCs) . METHODS:The intracellular Ca 2+ concentration([Ca 2+ ]i) of isolated rat HSCs was measured with a fluorescence microscopic imaging system.Quantitative PCR was per-formed to determine the transcriptional levels of 5-HT receptors and endoplasmic reticulum(ER) proteins involved in Ca 2+ storage and release in cultured rat HSCs. RESULTS:Distinct from quiescent cells,activated HSCs exhibited[Ca 2+ ]i transients following treatment with 5-HT,which was abolished by U-73122,a phospholipase C inhibitor.Upregulation of 5-HT2A and 5-HT2B receptors,but not 5-HT3,was prominent during trans-differentiation of HSCs.Pretreatment with ritanserin,a 5-HT2 antagonist,inhibited[Ca 2+ ]i changes upon application of 5-HT.Expression of type 1 inositol-5'-triphosphate receptor and type 2 sarcoplasmic/endoplasmic reticulum Ca 2+ ATPase were also increased during activation of HSCs and serve as the major isotypes for ER Ca 2+ storage and release in activated HSCs.Ca 2+ binding chaperone proteins of the ER,including calreticulin,calnexin and calsequestrin,were up-regulated following activation of HSCs. CONCLUSION:The appearance of 5-HT-induced[Ca 2+ ]i response accompanied by upregulation of metabotropic 5-HT2 receptors and Ca 2+ transporting/chaperone ER proteins may participate in the activating process of HSCs.
AIM：To investigate serotonergic Ca 2＋ signaling and the expression of 5-hydroxytryptamine（5-HT） receptors,as well as Ca 2＋ transporting proteins,in hepatic stellate cells（HSCs） . METHODS：The intracellular Ca 2＋ concentration（[Ca 2＋ ]i） of isolated rat HSCs was measured with a fluorescence microscopic imaging system.Quantitative PCR was per-formed to determine the transcriptional levels of 5-HT receptors and endoplasmic reticulum（ER） proteins involved in Ca 2＋ storage and release in cultured rat HSCs. RESULTS：Distinct from quiescent cells,activated HSCs exhibited[Ca 2＋ ]i transients following treatment with 5-HT,which was abolished by U-73122,a phospholipase C inhibitor.Upregulation of 5-HT2A and 5-HT2B receptors,but not 5-HT3,was prominent during trans-differentiation of HSCs.Pretreatment with ritanserin,a 5-HT2 antagonist,inhibited[Ca 2＋ ]i changes upon application of 5-HT.Expression of type 1 inositol-5’-triphosphate receptor and type 2 sarcoplasmic/endoplasmic reticulum Ca 2＋ ATPase were also increased during activation of HSCs and serve as the major isotypes for ER Ca 2＋ storage and release in activated HSCs.Ca 2＋ binding chaperone proteins of the ER,including calreticulin,calnexin and calsequestrin,were up-regulated following activation of HSCs. CONCLUSION：The appearance of 5-HT-induced[Ca 2＋ ]i response accompanied by upregulation of metabotropic 5-HT2 receptors and Ca 2＋ transporting/chaperone ER proteins may participate in the activating process of HSCs.
基金
Supported by Grants from the Korean National Research Foun-dation(2010-0014617)
the Myung Sun Kim Memorial Founda-tion(2009)
the Yonsei University Faculty Research Grant(2004)
