Leptin, a therapeutic avenue for the treatment of vascular disease, focus on congenital and antiretroviral therapy-associated lipodystrophies

项目摘要 脂肪营养不良是一种先天性疾病或后天获得的条件，这可能是由抗逆转录病毒引起的 治疗（ART）。脂肪营养不良的特征在于完全或部分缺乏脂肪组织，导致剧烈的脂肪变性。 瘦素水平降低、代谢紊乱和心血管疾病（CVD）。然而，分子 脂肪营养不良引起CVD的机制仍不清楚。此外，虽然FDA最近 批准使用瘦素作为治疗，以尽量减少脂肪营养不良患者的代谢功能障碍， 瘦素替代疗法改善脂肪营养不良相关的CVD仍然是未知的。目前的目标是 应用是联合收割机基因工程动物模型和药理学方法的使用与 细胞培养以鉴定脂肪营养不良诱导内皮功能障碍的分子机制， 确定瘦素治疗是否恢复脂肪代谢障碍相关的内皮功能障碍。初步数据 对于本申请，报告了先天性和先天性肥胖小鼠模型中脂肪量和瘦素水平降低， ART诱导的脂肪代谢障碍与内皮依赖性舒张功能受损相关。而且我们 显示脂肪代谢障碍增加血管氧化应激， 血管，减少血管过氧化物酶体增殖物激活受体γ（PPARγ），并促进 以RANTES/CCR 5、IL-1β、MCP-1、F4/80和加塔-3水平升高为特征的血管炎症。我们 还表明用tempol或Nox 1/Nox 4抑制剂清除ROS恢复内皮功能， 缺乏可防止脂肪营养不良诱导的内皮功能障碍和血管炎症。此外，我们发现， 瘦素补充，恢复内皮功能，增加过氧化物酶体增殖物激活受体γ，减少Nox 1， 分离的内皮细胞，降低RANTES/CCR 5表达并逆转血管炎症。最后我们 报告称，内皮细胞中瘦素敏感性的增加可以特异性地防止脂肪代谢障碍诱导的内皮细胞 功能障碍和血管炎症。基于这些发现，我们假设， 内皮细胞瘦素信号传导损害内皮依赖性舒张，并通过 脂肪营养不良中的Nox 1依赖机制。将通过以下三个目标检验这一假设：K99： 目的1：脂肪代谢障碍通过Nox 1介导的、PPARγ依赖的机制触发内皮功能障碍。 K99/R 00：目的2：内皮瘦素信号转导减少损害小鼠模型的内皮功能 脂肪营养不良。R 00：目的3：瘦素通过降低内皮细胞增殖减少血管免疫细胞浸润 RANTES/CCR 5表达。

PROJECT SUMMARY Lipodystrophy is a congenital disorder or a condition acquired later in life, which can be caused by antiretroviral therapies (ART). Lipodystrophy is characterized by a total or partial absence of adipose tissue resulting in drastic reductions in leptin levels, metabolic disorders and cardiovascular disease (CVD). However the molecular mechanisms whereby lipodystrophy causes CVD are still unclear. In addition, although the FDA recently approved the use of leptin as a therapy to minimize the metabolic dysfunction in lipodystrophic patients, whether leptin replacement therapy improves lipodystrophy-associated CVD remains unknown. The goal of the present application is to combine the use of genetically engineered animal models and pharmacological approaches with cell cultures to identify the molecular mechanism whereby lipodystrophy induces endothelial dysfunction and determine whether leptin treatment restores lipodystrophy associated endothelial dysfunction. Preliminary data for this application report that reduction in adipose mass and leptin levels in mouse models of congenital and ART-induced lipodystrophy is associated with impaired endothelium-dependent relaxation. Furthermore, we show that lipodystrophy increases vascular oxidative stress, elevates endothelial Nox1 expression in the vasculature, reduces vascular peroxisome proliferator-activated receptor gamma (PPARγ) and promotes vascular inflammation characterized by elevated RANTES/CCR5, IL-1β, MCP-1, F4/80, and GATA-3 levels. We also show that ROS scavenging with tempol or the Nox1/Nox4 inhibitor restores endothelial function and Nox1 lack prevents lipodystrophy-induced endothelial dysfunction and vascular inflammation. Moreover, we find that leptin supplementation, restores endothelial function, increases PPARγ, reduces Nox1 in aortae and freshly isolated endothelial cells, reduces RANTES/CCR5 expression and reverts vascular inflammation. Finally, we report that increasing leptin sensitivity in endothelial cells specifically prevents lipodystrophy-induced endothelial dysfunction and vascular inflammation. Based on these findings, we hypothesized that the reduction in endothelial leptin signaling impairs endothelium-dependent relaxation and promotes vascular inflammation via Nox1 dependent mechanisms, in lipodystrophy. This hypothesis will be tested with the three following aims: K99: Aim 1: lipodystrophy triggers endothelial dysfunction via Nox1-mediated, PPARγ-dependent mechanisms. K99/R00: Aim 2: reduction in endothelial leptin signaling impairs endothelial function in mouse models of lipodystrophy. R00: Aim 3: leptin reduces vascular immune cell infiltration via decreasing endothelial RANTES/CCR5 expression.