Department of Endocrinology, Xuzhou Central Hospital, Xuzhou Institute of Medical Sciences, Affiliated Hospital of Southeast University, Xuzhou, Jiangsu, China.
Department of Diabetes, School of Life Course Sciences, King's College London, Guy's Campus, London, UK.
J Diabetes Investig. 2020 Mar;11(2):307-314. doi: 10.1111/jdi.13124. Epub 2019 Aug 20.
AIMS/INTRODUCTION: Type 2 diabetes mellitus is a chronic metabolic disorder characterized by islet β-cell dysfunction, which might result from the activation of islet stellate cells (ISCs). Our recent study showed that a specific population of ISCs is prone to be activated in type 2 diabetes mellitus accompanied by reduced secretion of insulin. The wingless-type MMTV integration site family member 5a (Wnt5a)/frizzled-5 signaling pathway might play an important role in this process. The present study aimed to explore the effects of Wnt5a on the activation of ISCs isolated from db/db mice.
ISCs were isolated from db/db mice and matched db/m mice. Immunohistochemistry and western blotting analysis were applied for the determination of Wnt5a expression. Exogenous Wnt5a and lentivirus containing the target gene Wnt5a short hairpin ribonucleic acid were used as a molecular intervention. The experiment of transwell and wound healing was used to evaluate the migration of the isolated ISCs.
Our data showed that the expression of Wnt5a and frizzled-5 was decreased in the ISCs isolated from db/db mice compared with db/m mice. Both the exogenous Wnt5a and the overexpression of Wnt5a could inhibit the outgrowth rate of ISCs from islets, and its viability, migration and α smooth muscle actin expression. These changes were associated with the inactivation of the Smad2/3 signaling pathway in a frizzled-5-dependent manner.
Our observations revealed a potential role of Wnt5a in preventing ISC activation. The maintenance of quiescent ISCs might be a desirable outcome of therapeutic strategies for diabetes mellitus.
目的/引言：2 型糖尿病是一种慢性代谢紊乱，其特征是胰岛β细胞功能障碍，这可能是由于胰岛星状细胞（ISCs）的激活所致。我们最近的研究表明，在 2 型糖尿病中，特定的 ISC 群体容易被激活，同时伴随着胰岛素分泌减少。Wnt5a/Frizzled-5 信号通路可能在这个过程中发挥重要作用。本研究旨在探讨 Wnt5a 对 db/db 小鼠分离的 ISCs 激活的影响。
从 db/db 小鼠和匹配的 db/m 小鼠中分离 ISCs。免疫组织化学和 Western blot 分析用于确定 Wnt5a 的表达。外源性 Wnt5a 和含有靶向基因 Wnt5a 短发夹 RNA 的慢病毒被用作分子干预。Transwell 和伤口愈合实验用于评估分离的 ISCs 的迁移。
我们的数据表明，与 db/m 小鼠相比，db/db 小鼠分离的 ISCs 中 Wnt5a 和 Frizzled-5 的表达降低。外源性 Wnt5a 和 Wnt5a 的过表达均可抑制胰岛 ISCs 的生长速度，以及其活力、迁移和α平滑肌肌动蛋白的表达。这些变化与 Smad2/3 信号通路的失活有关，这是一种 Frizzled-5 依赖性方式。
我们的观察结果揭示了 Wnt5a 在防止 ISC 激活中的潜在作用。维持静止的 ISC 可能是糖尿病治疗策略的理想结果。
