热敏感性通道TRPV1及产热分子UCP1缺失致肥胖性高血压的机制

Dysfunction of adipose energy metabolism is the pivotal pathophysiological basis for obese hypertension, but its mechanism remains unclear. Uncoupling protein 1 (UCP1), which can be modulated by mitophagy, is the key thermogenic molecule for energy metabolism in brown adipose tissue. Our preliminary research showed that double knockout of UCP1 gene and transient receptor potential vanillic subtype 1 (TRPV1) gene, which encodes a thermosensitive channel, cause more severe obesity and hypertension compared with UCP1 knockout mice. This result indicated that TRPV1 knockout aggravates obese hypertension caused by dysfunction of UCP1, but its mechanisms needed to be clarified. We proposed that deficency of TRPV1 and UCP1 blocks mitophagy regulation, aggravates subsequently the mitochondrial dysfunction, and, eventually, causes obese hypertension.We plan to observe the basal metabolic rate, core temperature, vascular function, mitophagy function in brown fat, mitochondrial membrane potential, thermogenesis function and ROS generation in TRPV1/UCP1 knockout mice. We want to explore the molecular mechanisms of obese hypertension caused by deficency of TRPV1 and UCP1. This study will provide a new pathway for the prevention of obese hypertension.

脂肪能量代谢障碍是导致肥胖性高血压的重要病理生理基础。棕色脂肪的产热分子解偶联蛋白1(UCP1)是能量代谢的关键，线粒体自噬对UCP1有重要调节作用。我们前期实验发现，TRPV1可影响肝细胞线粒体自噬；UCP1和热敏感通道(TRPV1)双基因敲除的小鼠与UCP1敲除小鼠比较，肥胖及高血压程度更重，提示TRPV1缺失对UCP1功能异常致肥胖及血压升高有明显促进作用。我们提出TRPV1及UCP1功能缺失可阻断线粒体自噬的调节作用、影响棕色脂肪细胞线粒体功能、导致肥胖性高血压的假说。本项目拟采用TRPV1、UCP1单基因及双基因敲除小鼠模型，在整体与离体水平研究其基础代谢率、核心体温和血管功能的变化，揭示棕色脂肪线粒体自噬功能、线粒体膜电位、产热功能的改变及ROS生成的变化，阐明TRPV1及UCP1功能缺失致肥胖性高血压的机制，为其防治提供新的思路。

脂肪能量代谢障碍是导致肥胖性高血压的重要病理生理基础。棕色脂肪的产热分子解偶联蛋白1(UCP1)是能量代谢的关键，线粒体功能对UCP1有重要调节作用。我们前期实验发现，TRPV1可影响肝细胞线粒体功能；提示TRPV1缺失对UCP1功能异常致肥胖及血压升高有明显促进作用。.本研究采用TRPV1、UCP1单基因及双基因敲除小鼠模型，在整体与离体水平研究其基础代谢率、核心体温和血压的变化。结果显示， TRPV1-/-/UCP1-/-组小鼠体重明显比WT, TRPV1-/- 和 UCP1-/-组小鼠体重更重。TRPV1-/-/UCP1-/-组小鼠鼠尾血压、动态血压和甘油三酯水平也比其他三组高)。TRPV1-/-/UCP1-/-组小鼠棕色脂肪(BAT)和附睾、皮下、肾周和肠系膜白色脂肪的重量最重。TRPV1-/-/UCP1-/-组小鼠与其他三组相比，昼夜耗氧量均最低。TRPV1-/-/UCP1-/-组和UCP1-/-组呼吸商比WT和TRPV1-/-组小鼠高。线粒体功能检测发现，与其他三组相比，TRPV1-/-/UCP1-/-组小鼠线粒体功能损害更严重。原代培养棕色脂肪细胞，测定胞浆和线粒体ROS产生。TRPV1-/-/UCP1-/-组BAT细胞胞浆和线粒体超氧阴离子产生比其他三组相比显著增加，线粒体钙氢离子交换功能明显降低。TRPV1-/-/UCP1-/-组线粒体CI OXPHOS、CI+II OXPHOS以及ETS,ETS II明显增强，CI Leak有降低趋势。Western blot显示，TRPV1-/-/UCP1-/-组脂肪分化因子PRDM16、C/EBPβ、PPARγ较其他三组显著降低，脂质分解因子PPARδ、HSL蛋白表达较其他三组显著降低，脂肪酸合成酶(FAS)也显著降低。TRPV1-/-/UCP1-/-组小鼠棕色脂肪，UCP1和LETM1的表达水平较其他三组显著下调，乙酰辅酶A羧化酶（ACC）则显著上调。.以上结果提示UCP1和TRPV1双基因敲除的小鼠更容易发生肥胖和高血压，TRPV1-/-/UCP1-/-组小鼠静息耗氧量和自发活动明显降低，这与棕色脂肪线粒体功能明显相关；线粒体膜电位、能量代谢功能的改变及ROS生成的变化可能是其重要机制。.