Ghrelin/GHSR通过AMPK信号通路调控动脉粥样硬化斑块稳定性的分子机制研究

As one of brain-gut peptide, ghrelin might be involved in pathogenesis of atherosclerosis (AS) which is considered as kind of chronic inflammatory disease. In preliminary work, we have successfully established AS mice model with GHSR -/- LDLR-/-, and showed that ghrelin not only inhibit AS plaque progression, but also increase its stability. However, the mechanism involved is not clear. Our further study confirmed that AMPK phospholation level in endothelial cells (ECs) and smooth muscle cells (SMCs) from plaques is significant lower in double-deficiency mice than that of LDLR-/- mice. Base on these results, plus literature retrieval, we build our hypothesis that ghrelin regulate pathogenesis of AS plaque through GHSR via AMPK pathway, by means of inhibition of infammation in plaque, as well as migration and apoptosis of SMCs. In the present study, we aim to intevene GHSR, AMPK, P53-P21-CDK, IRE1α, NF-κB, by using GHSR -/- LDLR-/- mice and GHSR-/- mice with femoral artery injuried mice model, to elucidate regulatory effect of GHSR- AMPK- IRE1α/XBP1 -NF-κB and GHSR- AMPK - P53-P21-CDK network on stability of AS plaque. The significance of this study lies in thoroughly exploration of the relationship between ghrelin and AS pathogenesis, and possible finding of new regulatory target that might be used in AS prevention and treatment.

动脉粥样硬化（AS）是一种慢性炎症性疾病，脑肠肽（Ghrelin）可能在该过程中发挥重要作用。我们前期工作已成功制备Ghrelin受体（GHSR）及低密度脂蛋白受体（LDLR）双缺失小鼠的AS模型，发现Ghrelin可抑制AS斑块进展并增加其稳定性，但机制不清晰。通过文献检索和前期预试验，本课题提出了Ghrelin调控AS斑块的稳定性是通过其受体GHSR发挥作用，由AMPK信号介导，抑制AS斑块炎症反应、平滑肌细胞的迁移和凋亡。采用本课题组制备的双缺失小鼠模型，以及细胞模型和股动脉套管炎症损伤模型，通过干预AMPK信号转导途径的多个中间环节，阐明GHSR- AMPK- IRE1α/XBP1 -NF-κB及GHSR- AMPK - P53-P21-CDK间的调控网络在AS斑块稳定性中的作用机制。本研究对探讨Ghrelin与AS斑块稳定性的关系具有重要理论意义，也为AS的防治提出新的调控靶点。

动脉粥样硬化（AS）是一种慢性炎症性疾病，脑肠肽（Ghrelin）可能在该过程中发挥重要作用。通过将Ghrelin受体（GHSR）缺失的小鼠同低密度脂蛋白缺失的小鼠杂交，我们成功培育出GHSR-/-LDLR-/-双缺失小鼠的AS模型。对不同AS模型小鼠进行表型比对分析，发现Ghrelin受体缺失可以加剧AS斑块不稳定性，促进血管炎症反应。结合前期对GHSR缺失小鼠动脉内皮细胞AMPK通路激活程度的研究，初步证明了AMPK通路在Ghrelin调节AS斑块稳定性过程中的作用。为了更进一步阐述Ghrelin作用的下游机制，我们利用THP-1及HUVECs构建了AS细胞模型，探讨了Ghrelin调节过程中AMPK/NF-κB通路的活化情况。发现Ghrelin作用于细胞表面GHSR后，可以抑制细胞内AMPK/NF-κB信号通路活化的作用，从而调节内皮细胞及单核细胞的炎症反应，抑制内皮细胞同单核细胞间的黏附作用，同时抑制ICAM-1、VCAM-1、MCP-1、IL-1β、IL-8等炎症因子的表达，从而调节AS斑块稳定性。本研究探讨了Ghrelin与AS斑块稳定性的关系，并强调了AMPK/NF-κB通路在其中的作用，为AS的防治提出了新的调控靶点。