“FGF21抵抗”对血管内皮细胞衰老的影响和机制研究

Senescence of vascular endothelial cells is one of the key mechanisms underlying the occurrence and development of vascular aging and aging-associated cerebrovascular diseases including atherosclerosis. Fibroblast growth factor 21 (FGF21) has been widely recognized as a metabolic regulator that is elevated in response to caloric and nutritional restrictions, by which it improves glucose and lipid metabolism in mice and humans...　　Our preliminary studies revealed that the concentration of blood circulating FGF21 (cFGF21) elevated with aging in healthy volunteers. During the course of in vitro subculture, FGF21 was noted to be beneficial for delaying both replicative senescence and H2O2-induced premature senescence in a SIRT1-dependent manner. Based on aging-associated increase of cFGF21 and decrease of SIRT1, we herein propose that HUVECs also develop “FGF21 resistance” during the course of senescence, a phenomenon observed in other types of cells such as adipocytes...　　In this project, we are planning to comprehensively evaluate the change of cFGF21 concentration during healthy aging by employing our unique aging subjects collected during the past decades. We aimed to dissect the effects of FGF21 on the regulation of HUVEC senescence and function with FGF21 concentration used within the range of physiological variation. Finally, we will verify the existence of “FGF21 resistance” during HUVEC senescence, and demonstrate the underlying molecular mechanisms and signaling networks during the interplays between “FGF21 resistance” and endothelial senescence, through which we intend to identify the eventual FGF21 responsive targets that can be employed to prevent “FGF21 resistance” during endothelial senescence...　　The outcome of this investigation could serve as a theoretical basis for prevention and delay the occurrence and development of vascular aging and aging-associated cerebrovascular diseases.

血管内皮细胞的衰老是血管衰老和增龄性心脑血管疾病发生发展的核心机制之一。血液循环中的FGF21（cFGF21）在小鼠和人体内发挥重要的改善糖脂代谢的作用。我们的初步临床检测发现健康人的cFGF21浓度随增龄而升高，但也同时发现FGF21可在in vitro水平延缓人脐静脉内皮细胞（HUVECs）的复制型衰老，并保护细胞因H2O2处理而导致的损伤和早衰，由此我们提出了在HUVECs中可能存在“FGF21抵抗”的现象。通过本项目，我们希望能全面评估健康衰老过程中人cFGF21浓度的变化；借助转录组测序及转基因动物实验等技术，研究FGF21在生理浓度变化范围内对HUVECs衰老和功能的影响及相关分子机制；验证HUVECs衰老过程中可能存在的“FGF21抵抗”，明确其分子机制并鉴定可能改善“FGF21抵抗”的作用靶点，为更全面地解析血管衰老，开发延缓或逆转血管衰老的治疗策略提供新的思路和理论依据。

.血管内皮细胞的衰老是血管衰老和增龄性心脑血管疾病发生发展的核心机制之一。FGF21在小鼠和人体内发挥重要的改善糖脂代谢的作用。我们早期的实验发现高浓度外源性的FGF21（5000 pg/mL）可在in vitro水平延缓人脐静脉内皮细胞（HUVECs）的复制性衰老，保护细胞因H2O2处理而导致的损伤和早衰，并推测在HUVEC的衰老过程可能伴随着“FGF21抵抗”的现象。健康人的血浆FGF21的生理浓度是多少，在生理浓度下FGF21是否依然对血管内皮细胞有类似作用，是本项目研究的主要目标。.本项目检测了212位20-70的健康受试者的空腹血浆FGF21浓度，发现20至70岁健康人血浆FGF21浓度的中位值在113 pg/mL - 210 pg/mL区间，不超过400 pg/mL的浓度可被视为在生理浓度范围，增龄可独立地促进血浆FGF21浓度的增加。接着，我们验证了在生理浓度下，FGF21也可促进年轻HUVEC的糖酵解和一氧化氮分泌、缓解H2O2造成的细胞氧化损伤，下调炎症、凋亡等相关通路，揭示了受FGF21调控的下游靶基因以及不同程度上依赖于SIRT1的调控机制。随后，我们在衰老的HUVEC中从多层面证实了存在“FGF21抵抗”的现象，使FGF21对细胞的保护和增益性作用随细胞的衰老而降低；同时鉴定了一个可能调控“FGF21抵抗”的关键因子，并对此因子开展更深入的研究。在动物水平上，高脂喂养肝脏内特异性敲除FGF21的小鼠可导致小鼠的代谢异常，并伴随有一系列的血管结构和功能的异常，包括高血压、血管管腔增加，血管硬化和老化。.作为本课题的延伸，我们分析了血浆中高浓度的cFGF21在心血管疾病中的风险预测作用。同时也展示了血液中cFGF21的浓度可被多种生活方式（吸烟、饮酒、饮食、节食、运动...）所干预，成为辅助评估和监测现代人“健康生活”的敏感的指标。.本项目系统地研究了FGF21对从血管内皮细胞到人体的多重保护和增益性的作用和机制，探索随衰老伴随的“FGF21抵抗”现象和机制，为将来可能的靶向调控FGF21信号通路来延缓血管衰老，预防和治疗衰老导致的心脑血管疾病提供理论基础。.