基于ABCA1介导JAK2/STAT3及TLR4通路辛酸抑制炎症反应作用机制研究

Atherosclerosis (AS) is the main pathological basis of heart and cerebrovascular diseases. AS is considered as a kind of chronic inflammatory disease, which is a hot and difficult point for prevention and control. Recent studies have found that ABCA1 can not only promote the reverse cholesterol transport（RCT）, reduce the formation of foam cells, but also regulate the inflammatory response of AS. Fatty acid and lipid metabolism, inflammatory reaction is closely related. According to the report that the saturated fatty acids are the risk factors of AS, but our study found that medium chain fatty acids (MCFAs) belong to saturated fatty acids can promote RCT, improve the metabolism of cholesterol and reduce the AS plaque of ApoE-/- mice and increase the ABCA1 expression of liver. Further study found that octylic acid can increase the ABCA1 protein expression of aorta, regulate the gene expression of inflammatory pathways and inhibit the inflammatory response of aorta and macrophage. Those indicate that octylic acid can inhibit the inflammatory reaction and improve AS by ABCA1, and the specific regulation mechanism is not clear. This research aims to clarify the regulation mechanism of octylic acid on the ABCA1 and on the influence of inflammatory cytokines and JAK2/STAT3 and TLR4 signaling molecules. The technology of siRNA gene silencing and over expression of ABCA1 gene plasmid transfection will be used to validate the mechanism on cell. Using the ABCA1 knockout mice to be confirmed the mechanism. This study will elucidate the mechanism of MCFAs on anti-inflammation, and provide new ideas and scientific basis for the prevention and treatment of AS in the future.

动脉粥样硬化(AS)是心、脑血管疾病的病理基础，属于一种慢性炎性疾病，为防治的热点和难点。研究发现ABCA1能够促进胆固醇逆转运（RCT），减少泡沫细胞的形成，还能调控AS炎症反应。脂肪酸与血脂、炎症反应密切相关，普遍认为饱和脂肪酸是危险因素，但我们研究发现中链脂肪酸（MCFAs）能够促进RCT，减轻ApoE-/-小鼠AS斑块形成，上调肝脏ABCA1的表达，而且发现辛酸能够抑制主动脉及巨噬细胞炎症反应，上调主动脉ABCA1和调控炎症通路的基因表达。提示辛酸能够通过ABCA1抑制炎症改善AS，具体机制不清。本课题拟通过细胞实验阐明辛酸上调ABCA1的机制和对JAK2/STAT3及TLR4通路信号分子及炎症因子表达的影响，采用siRNA基因沉默/过表达ABCA1质粒转染技术进行机制验证，并通过ABCA1-/-小鼠实验证实。阐明辛酸抗炎的机制，为防治AS提供新思路和依据。

慢性炎症是动脉粥样硬化（AS）关键致病因素，抑制慢性炎症对防治AS性心血管疾病（ASCVD）具有重要意义。研究发现ABCA1能够促进胆固醇逆转运（RCT），减少泡沫细胞的形成，还能调控AS炎症反应。脂肪酸与血脂、炎症反应密切相关，我们前期研究发现中链脂肪酸能够促进RCT，减轻ApoE-/-小鼠AS斑块形成，上调肝脏ABCA1的表达，而且发现辛酸能够抑制主动脉及巨噬细胞炎症反应。本项目通过细胞实验证实辛酸能够上调ABCA1且调节JAK2/STAT3及TLR4的信号通路而降低炎症因子的表达，并采用siRNA基因沉默ABCA1基因质粒转染技术进行细胞实验验证，最后通过C57BL/6J小鼠和ABCA1基因敲除动物实验证实辛酸上调ABCA1调节JAK2/STAT3及TLR4的信号分子而降低炎症因子的作用。研究发现辛酸能够通过上调RWA264.7细胞LXR、Sp1表达介导ABCA1的表达增加，而上调JAK2/ STAT3通路而降低P65炎性因子的表达；辛酸干预ABCA1敲减的RAW246.7细胞后ABCA1显著升高，但JAK2/STAT3的表达未见显著改变，仅p-STAT3蛋白增高；辛酸能够上调C57BL/6J小鼠主动脉及小肠ABCA1表达，并且抑制TLR4的表达，抑制血清和小肠NF-κB、TNFα及MYD88炎性因子水平；敲除ABCA1后小鼠血清及小肠炎性因子显著升高，且辛酸表现出JAK2和STAT3显著降低，与高脂肪组比较辛酸抑制TLR4表达，NF-κB无显著性差异，而EPA较辛酸能够显著抑制TLR4表达，降低NF-κB的表达。以上研究证实了中链脂肪酸辛酸可以抑制炎症反应，其机制可以通过ABCA1调节JAK2/STAT3及TLR4的信号分子而降低炎症因子，为抗AS提供了新的治疗方法，也为中链脂肪酸应用于功能性食品提供了研究基础。