Department of Endocrinology and Metabolism, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
Clin Transl Med. 2022 Jun;12(6):e890. doi: 10.1002/ctm2.890.
Acetylcholine (ACh) and norepinephrine (NE) are representative neurotransmitters of parasympathetic and sympathetic nerves, respectively, that antagonize each other to coregulate internal body functions. This also includes the control of different kinds of hormone secretion from pancreatic islets. However, the molecular mechanisms have not been fully elucidated, and whether innervation in islets is abnormal in diabetes mellitus also remains unclear.
Immunofluorescence colocalization and islet perfusion were performed and the results demonstrated that ACh/NE and their receptors were highly expressed in islet and rapidly regulated different hormones secretion. Phosphorylation is considered an important posttranslational modification in islet innervation and it was identified by quantitative proteomic and phosphoproteomic analyses in this study. The phosphorylated islet proteins were found involved in many biological and pathological processes, such as synaptic signalling transduction, calcium channel opening and insulin signalling pathway. Then, the kinases were predicted by motif analysis and further screened and verified by kinase-specific siRNAs in different islet cell lines (αTC1-6, Min6 and TGP52). After functional verification, Ksr2 and Pkacb were considered the key kinases of ACh and NE in insulin secretion, and Cadps, Mlxipl and Pdcd4 were the substrates of these kinases measured by immunofluorescence co-staining. Then, the decreased expression of receptors, kinases and substrates of ACh and NE were found in diabetic mice and the aberrant rhythm in insulin secretion could be improved by combined interventions on key receptors (M3 (pilocarpine) or α2a (guanfacine)) and kinases (Ksr2 or Pkacb).
Abnormal innervation was closely associated with the degree of islet dysfunction in diabetic mice and the aberrant rhythm in insulin secretion could be ameliorated significantly after intervention with key receptors and kinases in the early stage of diabetes mellitus, which may provide a promising therapeutic strategy for diabetes mellitus in the future.
乙酰胆碱（ACh）和去甲肾上腺素（NE）分别是副交感神经和交感神经的代表性神经递质，它们相互拮抗，共同调节体内的各种功能。这也包括对胰岛不同种类激素分泌的控制。然而，其分子机制尚未完全阐明，糖尿病患者胰岛中的神经支配是否异常也尚不清楚。
通过免疫荧光共定位和胰岛灌注实验，结果表明 ACh/NE 及其受体在胰岛中高度表达，并能快速调节不同激素的分泌。磷酸化被认为是胰岛神经支配中的一种重要的翻译后修饰，本研究通过定量蛋白质组学和磷酸化蛋白质组学分析进行了鉴定。研究发现，磷酸化的胰岛蛋白参与了许多生物学和病理学过程，如突触信号转导、钙通道开放和胰岛素信号通路。然后，通过基序分析预测激酶，并用不同的胰岛细胞系（αTC1-6、Min6 和 TGP52）中的激酶特异性 siRNA 进行筛选和验证。经过功能验证后，Ksr2 和 Pkacb 被认为是 ACh 和 NE 调节胰岛素分泌的关键激酶，Cadps、Mlxipl 和 Pdcd4 是这些激酶的底物，可通过免疫荧光共染色进行检测。然后，在糖尿病小鼠中发现 ACh 和 NE 的受体、激酶和底物的表达减少，并且通过联合干预关键受体（M3（毛果芸香碱）或α2a（胍法辛））和激酶（Ksr2 或 Pkacb）可以改善胰岛素分泌的异常节律。
异常的神经支配与糖尿病小鼠胰岛功能障碍的严重程度密切相关，在糖尿病早期干预关键受体和激酶后，胰岛素分泌的异常节律可以得到显著改善，这可能为未来的糖尿病提供一种有前途的治疗策略。
Zotero 插件
