Defect of receptor-G protein coupling in human gallbladder with cholesterol stones.
Defect of receptor-G protein coupling in human gallbladder with cholesterol stones.
复制标题
人胆囊中受体-G 蛋白偶联缺陷与胆固醇结石。
DOI：
10.1152/ajpgi.2000.278.2.g251
复制
发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Behar,J
中科院分区：
文献类型：
--
作者：
Xiao,ZL;Chen,Q;Amaral,J;Biancani,P;Behar,J
与色素结石(PS)相比，胆固醇结石(CHS)患者的胆囊肌收缩和松弛功能受损，CCK受体结合能力降低。本研究采用~(35)S标记的鸟苷-5‘-O-(3-硫代三磷酸)([~(35)S]GTP-γS)结合、~(125)I标记的CCK-8放射自显影、免疫印迹和G蛋白定量等方法，研究CHS患者的胆囊壁中是否存在受体-G蛋白偶联。CCK和血管活性肠肽使[35S]GTPγS分别与GαI-3和Gsα结合显著增加。CHS的结合率低于PS(P<；0.01)。经无胆固醇脂质体处理后，CHS中降低的[35S]GTPγ与S的结合恢复正常(P<；0.01)。放射自显影和免疫印迹显示，与PS相比，CCK受体的光密度(OD)降低，受体-G蛋白偶联的OD值更低，而非偶联受体或G-αI-3蛋白的OD值更高(P<；0.001)。G蛋白定量结果还显示，CHS和PS中GαI-3和Gsα含量差异无统计学意义。我们的结论是，除了CCK受体结合能力受损外，CHS患者的胆囊肌细胞中还存在G受体蛋白偶联缺陷。这些变化可以在从质膜中去除多余的胆固醇后恢复正常。
Human gallbladders with cholesterol stones (ChS) exhibit an impaired muscle contraction and relaxation and a lower CCK receptor-binding capacity compared with those with pigment stones (PS). This study was designed to determine whether there is an abnormal receptor-G protein coupling in human gallbladders with ChS using35S-labeled guanosine 5′-O-(3-thiotriphosphate) ([35S]GTPγS) binding,125I-labeled CCK-8 autoradiography, immunoblotting, and G protein quantitation. CCK and vasoactive intestinal peptide caused significant increases in [35S]GTPγS binding to Gαi-3and Gsα, respectively. The binding was lower in ChS than in PS (P< 0.01). The reduced [35S]GTPγS binding in ChS was normalized after the muscles were treated with cholesterol-free liposomes (P< 0.01). Autoradiography and immunoblots showed a decreased optical density (OD) for CCK receptors, an even lower OD value for receptor-G protein coupling, and a higher OD for uncoupled receptors or Gαi-3protein in ChS compared with PS (P< 0.001). G protein quantitation also showed that there were no significant differences in the Gαi-3and Gsα content in ChS and PS. We conclude that, in addition to an impaired CCK receptor-binding capacity, there is a defect in receptor-G protein coupling in muscle cells from gallbladder with ChS. These changes may be normalized after removal of excess cholesterol from the plasma membrane.