TRPV1-Dependent Autonomic Control in Diabetes

TRPV1 依赖性糖尿病自主控制

• 批准号: 8694847
• 负责人: Andrea Zsombok
• 金额: $ 33.49万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8694847
• 关键词: Achievement; Agonist; Autonomic Dysfunction; Autonomic nervous system; Blood Glucose; Blood Pressure; Brain; Cells; Clinical; Conscious; Data; Diabetes Mellitus; Diabetic mouse; Drug Targeting; Electrophysiology (science); Euglycemic Clamping; Gene Expression; Gene Proteins; Glucagon; Gluconeogenesis; Glucose; Glucose Clamp; Glutamates; Glycogen; Glycolysis; Goals; Heart Rate; Hepatic; Homeostasis; Hypothalamic structure; In Vitro; Injection of therapeutic agent; Insulin; Knowledge; Laboratories; Lead; Liver; Location; Maintenance; Measures; Modeling; Monitor; Mus; Muscle; Neurons; Non-Insulin-Dependent Diabetes Mellitus; Outcome; Output; Peripheral; Physiological; Play; Population; Prevalence; Property; Public Health; Regulation; Research; Role; Serum; Signal Transduction; Site; Skeletal Muscle; Slice; Stereotaxic Techniques; Structure of dorsomedial hypothalamic nucleus; Synapses; System; Telemetry; Testing; Therapeutic Intervention; Tissues; Tracer; Vanilloid; Viral; blood glucose regulation; diabetic patient; glucose production; glucose uptake; glycemic control; hepatic gluconeogenesis; high risk; improved; in vivo; innovation; mouse model; neurotransmission; neurotransmitter release; novel strategies; optogenetics; paraventricular nucleus; patch clamp; postsynaptic; presynaptic; protein expression; public health relevance; receptor; research study; response; viral gene delivery

DESCRIPTION (provided by applicant): Systemic glucose homeostasis is substantially regulated by central autonomic circuits and there is a high risk of developing type 2 diabetes if autonomic dysfunction is present. Therefore, without a full understanding of the mechanisms governing the preautonomic neurons, there is a barrier to the understanding of the control of glycemic status. The overall long term goal of this proposal is to elucidate the fundamental relationship between central autonomic control and glucose homeostasis. The paraventricular nucleus (PVN) of the hypothalamus is a critical command center controlling autonomic outflow and, thereby, influencing glucose and energy homeostasis. Since impaired glucose homeostasis in diabetic patients involves central circuits controlling autonomic output, the immediate objective of this proposal is to identify transient receptor potential vanilloid type 1 (TRPV1)-dependent mechanisms involved in the regulation of preautonomic PVN neurons in the control of glycemic status using in vivo and in vitro approaches. The involvement of TRPV1 in diabetes has been established and recent studies from my laboratory have indicated that TRPV1 is a vital controller of preautonomic PVN neurons through increasing excitatory neurotransmitter release. Furthermore, this TRPV1- dependent excitation of liver-related PVN neurons was absent in a diabetic mouse model. Our preliminary observations demonstrate that activation of TRPV1 in the PVN lowers systemic blood glucose levels in control mice likely through increasing glucose uptake of the muscle and decreasing gluconeogenesis by the liver. These observations lead to the central hypothesis that preautonomic PVN neurons receive TRPV1-expressing inputs and these inputs are integrated into a coordinated autonomic output signal to generate an appropriate glycemic response. The proposed in vivo studies will determine the effect of TRPV1 activation in PVN circuits on autonomic endpoints. The effect of TRPV1 activation in PVN on glucose homeostasis will be determined using hyperinsulinemic-euglycemic clamp studies in conscious mice, and on blood pressure and heart rate using telemetry. Systems level studies using optogenetics will determine the effect of selective stimulation and inhibition of TRPV1 inputs on glucose homeostasis using TRPV1cre mice. Whole-cell, patch-clamp studies will reveal the cellular effects of activation and inhibition of TRPV1 inputs on PVN neurons, and we will identify preautonomic neuronal populations in the PVN regulated by TRPV1-expressing projections. Furthermore, the effect of TRPV1 activation on neurotransmission will be determined using photostimulation in TRPV1cre mice. These studies will define the role of central TRPV1 action on whole body glucose homeostasis through preautonomic PVN neurons, and will differentiate the importance of pre- and postsynaptic locations of TRPV1 on this system. The outcomes of the proposed studies hold the promise of opening innovative clinical strategies and drug targets for the improvement of glycemic status in diabetic patients via autonomic control.

描述（由申请人提供）：全身葡萄糖稳态基本上由中枢自主神经回路调节，如果存在自主神经功能障碍，则存在患 2 型糖尿病的高风险。因此，如果不充分了解控制前自主神经元的机制，对血糖状态控制的理解就会存在障碍。该提案的总体长期目标是阐明中枢自主控制与葡萄糖稳态之间的基本关系。下丘脑的室旁核（PVN）是控制自主神经流出的关键指挥中心，从而影响葡萄糖和能量稳态。由于糖尿病患者的葡萄糖稳态受损涉及控制自主神经输出的中枢回路，因此该提案的直接目标是使用体内和体外方法确定瞬态受体电位香草酸1型（TRPV1）依赖性机制，该机制涉及调节自主神经前PVN神经元以控制血糖状态。 TRPV1 与糖尿病的关系已经确定，我实验室最近的研究表明，TRPV1 通过增加兴奋性神经递质的释放，是自主神经前 PVN 神经元的重要控制器。此外，这种 TRPV1 依赖性肝脏相关 PVN 神经元的兴奋在糖尿病小鼠模型中不存在。我们的初步观察表明，PVN 中 TRPV1 的激活可能通过增加肌肉的葡萄糖摄取和减少肝脏的糖异生来降低对照小鼠的全身血糖水平。这些观察结果得出了一个中心假设，即前自主性 PVN 神经元接收表达 TRPV1 的输入，并且这些输入被整合到协调的自主输出信号中以产生适当的血糖反应。拟议的体内研究将确定 PVN 回路中 TRPV1 激活对自主神经终点的影响。 PVN 中 TRPV1 激活对葡萄糖稳态的影响将通过在清醒小鼠中进行高胰岛素-正常血糖钳夹研究来确定，并通过遥测技术来确定对血压和心率的影响。使用光遗传学的系统级研究将确定 TRPV1cre 小鼠选择性刺激和抑制 TRPV1 输入对葡萄糖稳态的影响。全细胞膜片钳研究将揭示 TRPV1 输入激活和抑制对 PVN 神经元的细胞影响，并且我们将鉴定 PVN 中受 TRPV1 表达投射调节的前自主神经元群体。此外，TRPV1 激活对神经传递的影响将通过 TRPV1cre 小鼠的光刺激来确定。这些研究将通过自主神经前 PVN 神经元定义中枢 TRPV1 作用对全身葡萄糖稳态的作用，并将区分 TRPV1 在此系统中突触前和突触后位置的重要性。拟议研究的结果有望开辟创新的临床策略和药物靶点，通过自主控制改善糖尿病患者的血糖状态。