Alterations of the Ca2＋ signaling pathway in pancreatic beta-cells isolated from db/db mice  

作　　者：Kuo Liang Wen Du Jingze Lu Fei Li Lu Yang Yanhong Xue Bertil Hille Liangyi Chen 

机构地区：[1]Department of General Surgery, XuanWu Hospital, Capital Medical University, Beijing 100053, China [2]National Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, China [3]The State Key Laboratory of Biomembrane and Membrane Biotechnology, Beijing Key Laboratory of CardiometabolicMolecular Medicine, Institute of MolecuLar Medicine, Peking University, Beijing 100871, China [4]Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195, USA

出　　处：《Protein & Cell》2014年第10期783-794,共12页蛋白质与细胞（英文版）

摘　　要：Upon glucose elevation, pancreatic beta-cells secrete insulin in a Ca2＋-dependent manner. In diabetic animal models, different aspects of the calcium signaling path- way in beta-cells are altered, but there is no consensus regarding their relative contributions to the development of beta-cell dysfunction. In this study, we compared the increase in cytosolic Ca2＊ （[Ca2＊]~） via Ca2＋ influx, Ca2＊ mobilization from endoplasmic reticulum （ER） calcium stores, and the removal of Ca2＋ via multiple mechanisms in beta-cells from both diabetic db/db mice and non- diabetic C57BL/6J mice. We refined our previous quan- titative model to describe the slow [Ca2＋]i recovery after depolarization in beta-cells from db/db mice. According to the model, the activity levels of the two subtypes of the sarco-endoplasmic reticulum Ca2＋-ATPase （SERCA） pump, SERCA2 and SERCA3, were severely down-reg- ulated in diabetic cells to 65% and 0% of the levels in normal cells. This down-regulation may lead to a reduc- tion in the Ca2＋ concentration in the ER, a compensatory up-regulation of the plasma membrane Na＋/Ca2＋ exchanger （NCX） and a reduction in depolarizationevoked Ca2＋ influx. As a result, the patterns of glucosestimulated calcium oscillations were significantly different in db/db diabetic beta-cells compared with normal cells. Overall, quantifying the changes in the calcium signaling pathway in db/db diabetic beta-cells will aid in the development of a disease model that could provide insight into the adaptive transformations of beta-cell function during diabetes development.Upon glucose elevation, pancreatic beta-cells secrete insulin in a Ca2＋-dependent manner. In diabetic animal models, different aspects of the calcium signaling path- way in beta-cells are altered, but there is no consensus regarding their relative contributions to the development of beta-cell dysfunction. In this study, we compared the increase in cytosolic Ca2＊ （[Ca2＊]~） via Ca2＋ influx, Ca2＊ mobilization from endoplasmic reticulum （ER） calcium stores, and the removal of Ca2＋ via multiple mechanisms in beta-cells from both diabetic db/db mice and non- diabetic C57BL/6J mice. We refined our previous quan- titative model to describe the slow [Ca2＋]i recovery after depolarization in beta-cells from db/db mice. According to the model, the activity levels of the two subtypes of the sarco-endoplasmic reticulum Ca2＋-ATPase （SERCA） pump, SERCA2 and SERCA3, were severely down-reg- ulated in diabetic cells to 65% and 0% of the levels in normal cells. This down-regulation may lead to a reduc- tion in the Ca2＋ concentration in the ER, a compensatory up-regulation of the plasma membrane Na＋/Ca2＋ exchanger （NCX） and a reduction in depolarizationevoked Ca2＋ influx. As a result, the patterns of glucosestimulated calcium oscillations were significantly different in db/db diabetic beta-cells compared with normal cells. Overall, quantifying the changes in the calcium signaling pathway in db/db diabetic beta-cells will aid in the development of a disease model that could provide insight into the adaptive transformations of beta-cell function during diabetes development.

关 键 词：diabetic beta-cells calcium signalingalterations SERCA pump db/db mice 

分 类 号：Q255[生物学—细胞生物学] Q949.326.1