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“img class=”content ” sizes=”(min-width: 320px) 320px, 100vw” src=”https://mmbiz.qpic.cn/mmbiz_png/x5F5KAyDKw19I4VvcibrfNia7lD1fial5KribXqZxjxMxtoc3ichKKz6ib3w5kJias8QNRBYGn80MM0AxEgOvRLib>p>width=”6400″ >Recently, the team of Professor Chen Yuguo/Xu Feng from the Chest Pain Center of Qilu Hospital Emergency Department of Shandong University published in Arteriosclerosis, Thrombosis, and Vascular Biology, the official journal of the American Heart Association Committee on Arteriosclerosis, Thrombosis, and Vascular Biology ( Chinese Academy of Sciences District 1, IF=8.313) published online titled “Macrophage ALDH2 stabilizing Rac2 is required for efferocytosis internalization and reduction of atherosclerosis development”. A research paper on inhibiting the development of atherosclerosis) revealed a new non-enzymatic mechanism of ALDH2 promoting macrophage burial and inhibiting the occurrence and development of atherosclerosis. It is a drug for acute coronary syndrome (ACS). The research and development provides new targets, especially to reduce the incidence of ACS in the 30%-50% Chinese population carrying the rs671 mutation of the ALDH2 gene crucial. Qilu Hospital of Shandong University is the first author and the corresponding author unit, Professor Xu Feng is the independent corresponding author of the article, doctoral student Zhang Jian and master student Zhao Xiangkai are the co-first authors.
ACS is a common high-risk disease in emergency medicine and a serious threat It is a key disease prevention and treatment in my country, and its pathological basis is the instability of atherosclerotic plaques. ALDH2 rs671 is the most common functional gene mutation site in the Chinese population. After the mutation of this site, the ALDH2 enzyme activity is significantly reduced, which brings a series of effects. Therefore, it is also commonly known as the “red face gene”. The team of Professor Chen Yuguo/Xu Feng has long been committed to the research on the role and mechanism of this common gene variant in acute and critical cardiovascular diseases in Chinese, in order to help the precise prevention and treatment of such diseases and provide Chinese people with more individualized prevention and treatment Strategy. Several previous clinical studies by the team found that ALDH2 gene mutation can lead to a significant increase in the risk of ACS and poor prognosis (JCMM 2011, 2018), but its specific mechanism has not been fully elucidated. Probing the internal mechanism of ALDH2 gene mutation promoting the occurrence of ACS has important clinical value and social significance for promoting the early prevention of this kind of disease and reducing its incidence.
First, the researchers used bone marrow transplantation to transfer APOE-/- span> ALDH2-/- and APOE -/- mouse bone marrow transplantation into APOE-/-In mice, APOE-/- ALDH2-/- Compared with APOE-/- marrow recipient mice, sup> marrow recipient mice The area of atherosclerotic plaques increased significantly, lipid accumulation and macrophage infiltration at the plaques increased significantly, collagen content decreased, and necrotic cores increased significantly, indicating that macrophage ALDH2 gene knockout promotes the progression of atherosclerosis.
Subsequently, the researchers explored how the ALDH2 gene knockout in myeloid cells increased the plaque necrosis core. The mechanism of necrotic cell accumulation in plaques was found to be due to decreased apoptotic cell clearance (expocytosis) rather than increased apoptotic cell production. Subsequent immunofluorescence, RNA-sequencing analysis, and flow cytometry assays also verified the inhibitory effect of ALDH2 knockout on exocytosis.
Further, the researchers found through bioinformatics analysis that 26 cells regulated by ALDH2 Among the related genes, the expression level of Rac2 has the most significant changes. Further proteomic analysis and verification experiments showed that Rac2 interacts with ALDH2, and ALDH2 gene knockout in macrophages can inhibit the expression and activation of Rac2. p>
Then, through in vitro and in vivo experiments, the researchers found that the realization of the burial effect of Rac2 depends on the Up-regulation of the protein, inhibition of Rac2 expression in macrophages can inhibit exocytosis, while overexpression of Rac2 can rescue the damaged exocytosis originally caused by ALDH2 knockout. This suggests that the reason why ALDH2 inhibits macrophage exocytosis is Rac2 Protein reduction.
Since the results of protein profiling suggested that ALDH2 protein and Rac2 protein might be combined, the researchers used immunofluorescence and laser Confocal, found that ALDH2 and Rac2 have obvious colocalization bit phenomenon. Endogenous binding, exogenous binding and in vitro binding experiments all proved that ALDH2 protein and Rac2 protein directly bind.
In order to investigate the effect of ALDH2 or rs671 variants on the stability of Rac2, the researchers used the protein synthase inhibitor cyclohexanoylidene amine (CHX)-treated macrophages, and found that compared with APOE-/- macrophages, APOE-/- ALDH2-/- Degradation of Rac2 was significantly increased in macrophages and confirmed that Rac2 protein is mainly degraded by the proteasomal pathway rather than the lysosomal pathway. The researchers further explored the internal mechanism of ALDH2 affecting Rac2 protein degradation, and found that ALDH2 WT can directly interact with Rac2 and inhibit Rac2 degradation by inhibiting the latter’s polyubiquitination at the K48 position of its 123rd lysine. Increases the stability of Rac2 protein.
Finally, the researchers extracted PBMC from healthy volunteers, The above results were verified in human samples, and it was found that compared with wild-type PBMCs, PBMCs with ALDH2 rs671 mutation had significantly lower burial capacity, because the rs671 mutation inhibited the expression of Rac2 protein, while the ALDH2 rs671 mutation PBMCs complemented wild-type PBMCs. Type ALDH2 rescued its impaired exocytosis.
The ALDH2-specific knockout mouse line, and through high-throughput mRNA sequencing and bioinformatics analysis and other research methods, combined with a large number of in vivo and in vitro experiments, it was found that the protein expressed by the ALDH2 wild-type gene can directly bind to the Rac2 protein and inhibit Rac2 The polyubiquitination modification of K48-linked form at the K123 site of protein inhibits Rac2 degradation, enhances Rac2 stability, thereby enhancing macrophage burial and inhibiting the development of atherosclerosis; however, the expression of the rs671 variant gene The protein lost this protective function, thus promoting the occurrence of ACS. The results of this study provide a new target for the precise prevention and treatment of ACS, and are of great significance for reducing the risk of ACS for 30%-50% of the Chinese population carrying rs671 mutations. This study further enriched the non-enzymatic activity spectrum of ALDH2, perfected the “double-edged sword” theory of ALDH2 in different acute and critical cardiovascular diseases, and provided more scientific basis for the future development of ALDH2-based tissue-specific therapy .
