REGULATION OF FAST AXONAL TRANSPORT DIABETIC NEUROPATHY

快速轴突运输糖尿病神经病的调节

• 批准号: 6311181
• 负责人: SCOTT THOMAS BRADY
• 金额: $ 33.7万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-30 至 2005-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6311181
• 关键词: diabetic neuropathy; hormone regulation /control mechanism; insulin; intracellular transport; kinesin; laboratory mouse; laboratory rat; neuronal transport; phosphorylation; protein kinase; protein kinase C; protoplasm motility

Diabetic neuropathies and their associated neurological complications represent one of the least tractable problems encountered in the clinics during long term management of the disease. Although the consequences and costs are clear, the underlying pathogenic mechanisms remain obscure. One proposed mechanism is alteration of axonal transport processes. Evidence that changes in axonal transport do occur in diabetic nerves exists, but the data do not establish whether this plays a primary or secondary role in development of diabetic neuropathy and the biochemical basis for these changes has been unclear. Recent studies in our laboratory have identified a series of kinase activities that inhibit or modulate fast axonal transport. Unexpectedly, several of these kinase activities are known to be altered in diabetic tissues, including protein kinase C and glycogen synthase kinase 3b. Preliminary data suggest that misregulation of kinase and phosphatase activities in nervous tissue associated with inappropriate levels of insulin may affect kinesin-based motility and targeting of specific neuronal proteins. This may provide a critical link between metabolic changes in diabetic patients and the mechanisms of fast axonal transport. In this application, we propose to analyze kinesin phosphorylation in normal and diabetic nerves in a rat model of type 1 diabetes. These experiments will determine the extent to which kinesin is altered in diabetic nerve and facilitate identification of kinase/phosphatase pathways involved. As specific phosphorylation patterns relevant to diabetes are identified, we will characterize biochemical and biophysical effects of kinesin phosphorylation at sites altered in diabetes. These studies will determine how kinesin phosphorylation may affect kinesin motor activities. Finally, we will evaluate changes in kinesin function in diabetic nerves. These experiments will determine the extent to which diabetes induced alterations in phosphorylation affect metabolic turnover of kinesin, interaction of kinesin with other motor proteins and kinesin based motility of membrane bounded organelles. Studies of the effects that insulin levels and diabetes may have on kinesin-based transport processes have the potential to identify promising protective strategies that will minimize or eliminate diabetic neuropathies in clinically controlled diabetics.

糖尿病神经性病变及其相关的神经系统并发症是临床长期治疗中遇到的最难处理的问题之一。虽然后果和代价是明确的，但潜在的致病机制仍然不清楚。一种被提出的机制是轴突运输过程的改变。有证据表明，糖尿病神经中确实发生轴突转运的变化，但数据并不能确定这在糖尿病神经病变的发展中是主要的还是次要的，而且这些变化的生化基础尚不清楚。我们实验室最近的研究发现了一系列抑制或调节快速轴突运输的激酶活性。出乎意料的是，这些激酶的一些活性已知在糖尿病组织中发生改变，包括蛋白激酶C和糖原合成酶激酶3b。初步数据表明，与胰岛素水平不适当相关的神经组织中激酶和磷酸酶活性的错误调节可能影响基于运动蛋白的运动和特定神经元蛋白的靶向。这可能提供了糖尿病患者代谢变化和快速轴突转运机制之间的关键联系。在这个应用中，我们建议在1型糖尿病大鼠模型中分析正常和糖尿病神经中激酶磷酸化。这些实验将确定糖尿病神经中肌动蛋白改变的程度，并有助于确定所涉及的激酶/磷酸酶途径。随着与糖尿病相关的特定磷酸化模式的确定，我们将描述糖尿病中激酶磷酸化位点改变的生化和生物物理效应。这些研究将确定激酶磷酸化如何影响激酶运动活动。最后，我们将评估糖尿病神经中运动蛋白功能的变化。这些实验将确定糖尿病诱导的磷酸化改变在多大程度上影响运动蛋白的代谢周转、运动蛋白与其他运动蛋白的相互作用以及基于膜结合细胞器的运动。研究胰岛素水平和糖尿病可能对基于运动蛋白的转运过程产生的影响，有可能确定有希望的保护策略，以减少或消除临床控制的糖尿病患者的糖尿病神经病变。