Mechanism of Diabetic Enteric Neuropathy

糖尿病肠神经病变的机制

• 批准号: 8516025
• 负责人: Shanthi K Srinivasan
• 金额: $ 28.7万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8516025
• 关键词: Ablation; Advanced Glycosylation End Products; Automobile Driving; Award; Cell Line; Chronic Disease; Complication; Complications of Diabetes Mellitus; Constipation; Data; Development; Diabetes Mellitus; Diabetic Autonomic Neuropathy; Disease; Enteral; Etiology; Event; Gastrointestinal Motility; General Population; Genetic; Healthcare Systems; Hyperglycemia; Laboratories; Lead; Light; Mediating; Mus; Neurons; Neuropathy; Oxidative Stress; Pathogenesis; Patients; Play; Prevalence; Prevention; Process; Research; Role; Signal Transduction; Signal Transduction Pathway; Streptozocin; TLR4 gene; Testing; Toll-like receptors; United States; Up-Regulation; cost; diabetic; gastrointestinal; glycation; in vivo; knock-down; motility disorder; neuron apoptosis; neuron loss; new therapeutic target; novel; overexpression; prevent; research study

DM mellitus (DM) is a common disorder with a prevalence of 15.5 million sufferers in the United States (1). In 2007, complications arising from DM cost the US healthcare system $58 billion (1). One major complication of DM is neuropathies. Constipation is a key consequence of enteric neuropathy and is significantly more common in DM patients with a prevalence of 60% compared to 15% in the general population. DM-associated enteric neuropathy results from hyperglycemia-induced neuronal apoptosis. However, the mechanism by which hyperglycemia drives neuronal apoptosis in DM remains enigmatic. In light of the increasing appreciation of the role of toll-like receptors (TLR) in driving a variety of chronic disease processes, especially those associated with oxidative stress and advanced glycation products (AGEs), which is known to result from hyperglycemia, we hypothesized that TLRs play a role in DM-associated enteric neuropathy. In support of this notion, we have observed that upregulation of one particular TLR, namely TLR4 is associated with hyperglycemia-induced neuronal apoptosis. Moreover, genetic and pharmacological ablation of TLR4 prevents both hyperglycemia-induced neuronal apoptosis and DM-associated colonic dysmotility. Thus, we hypothesize that hyperglycemia-induced activation of TLR4 results in neuronal apoptosis and, consequently, drives the colonic dysmotility associated with DM. To test the hypothesis and further investigate the underlying mechanism(s) of hyperglycemia-induced neuronal apoptosis, we will perform experiments to establish the role of TLR4 in mediating hyperglycemia-induced enteric neuronal apoptosis and elucidate the mechanism involved. Using primary enteric neurons from WT/TLR4-/- mice and knock down/overexpression strategies in the enteric neuronal cell line developed in our laboratory, we will establish the necessity and sufficiency of TLR4 in modulating hyperglycemia-induced enteric neuronal damage. The mechanism of hyperglycemia induced TLR4 activation will be examined focusing on the role of Advanced Glycation end products (AGES) and oxidative stress. Further, we will characterize the signaling events involved in hyperglycemia-induced TLR4 activation in enteric neuronal apoptosis focusing on the downstream targets of TLR4 including NF-¿B. Finally, we will determine the role of TLR4 on enteric neuronal apoptosis and colonic dysmotility in vivo. Our preliminary data indicate that streptozotocin (STZ) -induced DM results in enteric neuronal apoptosis and loss of mouse colonic myenteric neurons. These changes are ameliorated in TLR4-/- DM mice. Taken together these studies will not only elucidate a novel mechanism involving TLR4 in the pathogenesis of hyperglycemia-induced enteric neuronal apoptosis but also provide "proof of principle" for targeted therapies that could be used for the treatment or prevention of dysmotility associated with DM.

糖尿病(DM)是一种常见疾病，在美国有1550万患者(1)。在……里面 2007年，糖尿病引起的并发症使美国医疗系统损失了580亿美元(1)。一个主要的并发症是 糖尿病是一种神经病。便秘是肠道神经病变的一个关键后果，而且明显多于 在糖尿病患者中很常见，其患病率为60%，而普通人群的患病率为15%。DM关联 肠神经病变是由高血糖诱导的神经细胞凋亡引起的。然而，通过这种机制 糖尿病患者高血糖导致神经细胞凋亡仍是个谜。鉴于……的价值日益增加 Toll样受体(Toll-like Receptor，TLR)在多种慢性疾病过程中的作用 与氧化应激和晚期糖基化产物(AGEs)有关，已知这是由 高血糖时，我们假设TLRs在糖尿病相关肠神经病变中起作用。为了支持这一点 概念，我们观察到一个特定的TLR，即TLR4的上调与 高血糖诱导神经细胞凋亡。此外，TLR4的遗传和药物消融可以防止 高血糖诱导的神经细胞凋亡和糖尿病相关的结肠运动障碍。因此，我们 假设高血糖诱导的TLR4激活会导致神经元凋亡， 因此，会导致与糖尿病相关的结肠运动障碍。以检验假设，并进一步 研究高血糖诱导神经细胞凋亡的潜在机制(S)，我们将进行 TLR4在高血糖诱导肠神经细胞凋亡中作用的实验研究 阐明所涉及的机制。利用WT/TLR4-/-小鼠的原代肠道神经元和爆震 在我们实验室开发的肠神经细胞系中的下调/过表达策略，我们将建立 TLR4在调节高血糖所致肠神经损伤中的必要性和充分性。这个 高血糖诱导TLR4激活的机制将集中在高级糖蛋白的作用上 糖基化终末产物(AGEs)和氧化应激。此外，我们将描述信令事件的特征 TLR4参与高血糖诱导的肠神经细胞凋亡 TLR4的靶点包括核因子-B。最后，我们将确定TLR4在肠神经细胞凋亡和 活体内结肠运动障碍。我们的初步数据表明，链脲佐菌素(STZ)诱导的DM导致 小鼠结肠肌间神经元的缺失和肠神经元的凋亡。这些更改已在 TLR4-/-DM小鼠。综上所述，这些研究不仅将阐明与TLR4有关的一种新的机制，而且 高血糖诱导肠神经细胞凋亡的发病机制也为 可用于治疗或预防与糖尿病相关的运动障碍的靶向治疗。