Role of the skeletal muscle/pancreatic axis in type 2 diabetes

描述（由申请人提供）：2型糖尿病影响全球3.66亿人，仅在美国就有2580万人。它是21世纪世纪的主要公共卫生和经济负担之一。尽管问题的规模很大，但我们对疾病本身的基本理解是不完整的。在2型糖尿病患者中，运动可降低胰岛素抵抗 并增加胰腺对葡萄糖的敏感性。本R21应用的目的是探索骨骼肌收缩和胰腺胰岛素分泌的下游调节之间的细胞和分子联系。我们的中心假设是收缩的骨骼肌分泌靶向β细胞的肌因子，并参与葡萄糖刺激的胰岛素分泌的调节。为了验证这一假设，我们将从新诊断的2型糖尿病患者和非糖尿病年龄和性别匹配对照的股外侧肌产生原代细胞培养物，并使用电脉冲刺激（EPS）测量肌因子分泌组对收缩的反应。我们将利用最先进的蛋白质组学分析，包括2D电泳和质谱来鉴定非靶向肌因子，以及免疫测定来鉴定来自经历收缩的肌肉细胞的培养基中的靶向肌因子特征。我们将使用计算过滤来识别分泌的肌因子。我们的研究结果的整体生理验证将从这些肌因子对葡萄糖刺激的胰岛素分泌的集体作用中进行评估。根据我们对2型糖尿病的初步人体研究，运动训练后胰岛素分泌增加。我们预计，葡萄糖刺激胰岛素分泌和刺激分泌耦合将增加在培养基中培养的胰岛从EPS条件细胞。预期EPS期间分泌的肌因子介导胰腺胰岛素分泌增加。我们将使用化学抑制，siRNA和免疫细胞化学来探索内质网-高尔基体网络作为收缩诱导的肌因子分泌的可能分泌途径。这些研究将为全面和补充分析2型糖尿病临床相关人群中骨骼肌收缩和下游胰腺胰岛素分泌之间的生化联系提供初步步骤。我们希望这些原理验证研究将导致识别 特异性肌因子，可用于药物开发和糖尿病管理。这些发现也将进一步加深我们对骨骼肌作为内分泌器官及其在2型糖尿病葡萄糖代谢和胰岛素分泌调节中的作用的理解。

DESCRIPTION (provided by applicant): Type 2 diabetes affects 366 million people globally, and 25.8 million in the US alone. It is one of the major public health and economic burdens of the 21st century. Despite the scale of the problem our fundamental understanding of the disease itself is incomplete. In patients with type 2 diabetes, exercise reduces insulin resistance in muscle and increases glucose sensitivity in the pancreas. The objective of this R21 application is to explore the cellular and molecular links between skeletal muscle contraction and downstream regulation of pancreatic insulin secretion. Our central hypothesis is that contracting skeletal muscle secretes myokines that target β-cells and participate in the regulation of glucose stimulated insulin secretion. To test this hypothesis we will generate primary cell cultures from vastus lateralis muscle of newly diagnosed patients with type 2 diabetes and non-diabetic age and gender matched controls, and measure the myokine secretome response to contraction using electrical pulse stimulation (EPS). We will utilize state-of-the-art proteomic analyses, including 2D electrophoresis and mass spectrometry to identify non-targeted myokines, and immunoassays to identify a targeted myokine signature in the media from muscle cells that undergo contraction. We will use computational filtering to identify the secreted myokines. Global physiological validation of our findings will be assessed from the collective effect of these myokines on glucose stimulated insulin secretion from isolated human pancreatic islets. Based on our preliminary human studies in type 2 diabetes, insulin secretion was increased after exercise training. We expect that glucose stimulated insulin secretion and stimulus-secretory- coupling will be increased in islets incubated in media from EPS-conditioned cells. It is expected that myokines secreted during EPS mediate increased pancreatic insulin secretion. We will use chemical inhibition, siRNA and immunocytochemistry to explore the endoplasmic reticulum-Golgi network as a likely secretory pathway for contraction-induced myokine secretion. These studies will provide the initial steps towards a comprehensive and complementary analysis of a biochemical link between skeletal muscle contraction and downstream pancreatic insulin secretion in a clinically relevant population of individuals with type 2 diabetes. We expect that these proof-of-principle studies will lead to the identification of specific myokines that can be used for drug development and diabetes management. The discoveries will also further our understanding of skeletal muscle as an endocrine organ and its role in the regulation of glucose metabolism and insulin secretion in type 2 diabetes.