Mechanisms of Neuropeptides Action in Diabetes

描述(申请人提供)：周围神经病变在糖尿病足溃疡(DFU)的发展中起主要作用，因为疼痛不敏感，允许长期的组织损伤，直到形成慢性伤口。然而，我们单位和其他地方最近的研究表明，与神经病变相关的C-伤害性纤维缺乏局部分泌的神经肽会损害伤口的愈合，这可能是导致慢性DFU发展的主要原因之一，可能需要截肢。在目前的应用中，我们计划确定神经病变相关的神经肽缺乏和慢性炎症导致伤口愈合失败的机制。我们的主要假设是，与糖尿病诱导的促炎状态相关的神经肽的缺乏导致蛋白酪氨酸磷酸酶1B(PTP1B)表达和活性增加，导致生长因子信号转导减少，成纤维细胞功能降低，损害伤口愈合。此外，我们假设糖尿病诱导的PTP1B表达和神经病变相关神经肽缺陷导致肥大细胞功能受损，导致各种细胞因子和血管生成因子分泌不足，从而减少血管生成，进一步损害伤口愈合。我们最后假设，抑制PTP1B和肥大细胞稳定将促进糖尿病动物模型的创面愈合，并导致新的治疗方法的发展。为了验证我们的假设，我们在糖尿病患者中进行了一项前瞻性队列随访研究，以研究神经病变的严重程度和神经肽表达与PTP1B前足和前臂皮肤表达/活性以及肥大细胞数量和激活的关系。我们还将研究PTP1B、肥大细胞以及细胞因子和生长因子的变化与伤口愈合损害的关系。我们还建议进行动物研究，以检验影响这些机制的干预措施是否会影响伤口愈合的进展，并可能导致新的治疗方法的发展。该提案有三个具体目标：1)探讨糖尿病促炎症状态下神经肽缺乏导致PTP1B表达/活性增加和肥大细胞功能障碍与创面愈合受损的假说。研究PTP1B抑制是否能促进糖尿病患者创面愈合；研究神经肽缺乏是否导致糖尿病患者肥大细胞功能障碍和创面愈合障碍。该应用程序将包括来自Joslin-Beth以色列女执事足部中心、血管外科和内分泌学以及塔夫茨医学中心分子免疫药理学和药物发现实验室的研究人员的合作。不同学科之间的合作创造了非常强大的协同效应，将导致新的和临床上有用的数据，并有可能创造当前思维的范式转变，导致可以转化为新的治疗方法的开创性发现。

DESCRIPTION (provided by applicant): Peripheral neuropathy plays a major role in the development of diabetic foot ulceration (DFU) because of the pain insensitivity that allows prolonged tissue injury till a chronic wound has been developed. However, recent studies by our unit and elsewhere indicate that the neuropathy-associated lack of locally secreted neuropeptides by the C-nociceptive fibers impair wound healing and this may be of the major reasons that lead to the development of chronic DFU that may necessitate amputation. In the present application we plan to identify the mechanisms through which, the neuropathy-associated lack of neuropeptides and chronic inflammation lead to wound healing failure. Our primary hypothesis is that the lack of neuropeptides in association with the diabetes-induced pro-inflammatory state lead to increased expression and activity of protein tyrosine phosphatase 1B (PTP1B) causing reduced growth factor signaling, reduced fibroblast function and impaired wound healing. In addition, we hypothesize that diabetes-induced PTP1B expression and the neuropathy-related neuropeptide deficiency leads to impaired mast cell function results in deficient secretion of various cytokines and angiogenic factors that reduces angiogenesis and further impairs wound healing. We finally hypothesize that inhibition of PTP1B and mast cell stabilization in diabetic animal models will improve wound healing and lead to the development of new therapeutic approaches. In order to explore our hypothesis, we propose a prospective cohort follow up study in diabetic patients to study the relationship between the severity of neuropathy and neuropeptides expression to PTP1B forefoot and forearm skin expression/activity and mast cell number and activation. We will also examine the association between PTP1B, mast cells and changes in cytokines and growth factors to wound healing impairment. We also propose animal studies that will examine whether interventions that affect these mechanisms can affect the progress of wound healing and can lead to the development of new therapeutic approaches. The proposal has three specific aims: 1.) To explore the hypothesis that the deficiency of neuropeptides in association with the diabetes-induced pro-inflammatory state lead to increased PTP1B expression/activity and mast cell dysfunction are associated with impaired wound healing; 2.) To investigate whether PTP1B inhibition can improve wound healing in diabetes; 3.) To examine whether neuropeptide deficiency causes mast cell dysfunction and contributes to wound healing impairment in diabetes. The application will encompass the collaboration of investigators from the Joslin-Beth Israel Deaconess Foot Center, Vascular Surgery and Endocrinology and the Molecular Immunopharmacology and Drug Discovery Lab at Tufts Medical Center. The collaboration among the various disciplines creates very strong synergy and will lead to novel and clinically useful data and has the potential to create a paradigm shift in the current thinking, lead to seminal discoveries that can be translated to new therapeutic approaches.