【摘要】 目的：探讨RNA结合蛋白（RNA binding protein, RBP）转导蛋白β样蛋白2(transducin beta-like protein 2, TBL2)在缺氧/复氧（hypoxia/reoxygenation, H/R）诱导的心肌细胞损伤中的作用及其分子机制。方法：构建H9C2大鼠心肌细胞H/R模型，体外模拟心肌缺血。使用小干扰RNA(siRNA)沉默TBL2。通过CCK-8评估细胞活力，ELISA检测炎症因子白细胞介素-6(IL-6)和IL-1α,Western blot检测内质网应激（endoplasmic reticulum stress,ERS）标志物转录激活因子4(activating transcription factor 4, ATF4)的表达水平。运用RNA免疫共沉淀测序（RNA immunoprecipitation sequencing, RIP-Seq）筛选TBL2靶RNA，并进行GO和KEGG功能注释和富集分析。RIP-qPCR验证TBL2与ATF4的结合。结果：H/R处理后，细胞活力显著下降；IL-1α和IL-6升高，TBL2和ATF4蛋白上调（P<0.01）。TBL2沉默显著改善细胞活力并降低炎症因子表达（P<0.01），同时降低ATF4表达（P<0.05）。RIP-Seq显示TBL2结合的RNA主要涉及RNA剪接、蛋白加工与ERS等功能通路。RIP-qPCR证实ATF4 mRNA在TBL2复合物中显著富集（P<0.01）。结论：TBL2在心肌梗死细胞模型中显著高表达，参与心肌细胞的ERS与炎症反应。沉默TBL2可减轻H/R诱导的心肌细胞损伤，改善心肌细胞活力并减轻炎症反应与ERS。TBL2作为RBP，通过结合ATF4 mRNA，促进其表达，推动细胞损伤进展。更多还原

【Abstract】 AIM: To investigate the role of the RNA-binding protein(RBP) transducin beta-like protein 2(TBL2) in hypoxia/reoxygenation(H/R)-induced myocardial injury and its molecular mechanism. METHODS: The H/R model was established using H9C2 rat myocardial cells to simulate myocardial ischemia in vitro. TBL2 was silenced using small interfering(siRNA). Cell viability was assessed by CCK-8, inflammatory factors interleukin-6(IL-6) and IL-1α were measured by ELISA, and endoplasmic reticulum stress(ERS) marker activating transcription factor 4(ATF4) was detected by Western blot. RNA immunoprecipitation sequencing(RIP-Seq) was used to identify TBL2-targeted RNAs, followed by GO and KEGG functional annotation and enrichment analysis. RIP-qPCR was performed to validate the binding of TBL2 with ATF4. RESULTS: After H/R treatment, cell viability significantly decreased, IL-1α and IL-6 levels were elevated, and TBL2 and ATF4 protein levels were upregulated(P<0. 01). Silencing of TBL2 significantly improved cell viability and reduced the expression of inflammatory factors(P<0. 01), while also decreasing ATF4 expression(P<0. 05). RIP-Seq revealed that RNAs bound by TBL2 were primarily involved in RNA splicing, protein processing, and ERS-related pathways. RIP-qPCR confirmed that ATF4 mRNA was significantly enriched in the TBL2 complex(P<0. 01). CONCLUSION: TBL2 is significantly upregulated in the myocardial infarction cell model and participates in ERS and inflammatory response in myocardial cells. Silencing TBL2 alleviates H/R-induced cell damage, improves myocardial cell viability, and reduces inflammation and ERS. As an RBP, TBL2 promotes the expression of ATF4 by binding to its mRNA, thereby advancing cell injury.更多还原