老年慢性肾病（CKD）患者的肾小管上皮细胞生物利用度下降通常会导致与年龄相关的肾衰竭。 BRD4 是一种表观遗传调节因子，也是溴结构域和末端外 (BET) 蛋白家族的成员，在胚胎发生和癌症发展过程中充当组织和调节基因表达的超级增强子 (SE)。但BRD4在正常细胞中的生理功能研究较少。本研究旨在研究BRD4在正常细胞衰老过程中的某些生物学作用并探讨其潜在机制。本研究主要探讨BRD4蛋白在肾小管细胞衰老中的生物学功能。首先，我们使用 D-半乳糖 (D-gal) 和 BRD4 抑制剂 (Abbv-075) 在体内复制肾脏衰老。然后使用 D-gal 和 Abbv-075 测量与衰老相关的变化，例如体外细胞周期、β-半乳糖苷酶活性、细胞迁移和 p16 蛋白表达的变化。最后，我们敲低并过表达BRD4来研究肾小管细胞中与衰老相关的生理现象。在体外，D-gal处理诱导了明显的衰老相关变化，例如诱导细胞凋亡和细胞周期停滞、增加β-半乳糖苷酶活性以及上调原代人肾小管上皮细胞中 p16 蛋白的表达。在衰老小鼠模型中，D-gal 显着诱导肾功能损伤并减弱 BRD4 蛋白表达。同时，BRD4 抑制剂 (Abbv-075) 能够模拟 D-gal 诱导的细胞衰老。在体内，Abbv-075 还会降低肾功能并上调 p21 蛋白表达。当我们敲低BRD4的表达时，衰老相关的β-半乳糖苷酶（SA-β-gal）活性急剧增加，细胞迁移受到抑制，处于G0/G1期的细胞比例增加。此外，敲低还促进了衰老相关蛋白 p16 的表达。当肾小管细胞过表达BRD4时，D-gal诱导的细胞衰老模型中细胞衰老相关指标发生逆转。BRD4在体内和体外似乎对肾小管细胞的衰老具有积极作用。研究结果还表明，BRD4 抑制剂对于肿瘤治疗具有潜在的肾毒性作用。 BRD4 可能是衰老相关肾脏疾病的潜在治疗生物标志物和药物靶点，值得进一步研究。2024 转化男科和泌尿科。版权所有。

Age-related kidney failure is often induced by a decrease in the bioavailability of tubular epithelial cells in elderly chronic kidney disease (CKD) patients. BRD4, an epigenetic regulator and a member of the bromodomain and extraterminal (BET) protein family, acts as a super-enhancer (SE) organizing and regulating genes expression during embryogenesis and cancer development. But the physiological function of BRD4 in normal cells has been less studied. This study aimed to research certain biological roles of BRD4 in the process of normal cell aging and discuss the potential mechanisms.In this study, we investigated the biological functions of BRD4 proteins in the aging of renal tubular cells. At first, we used a D-galactose (D-gal) and BRD4 inhibitor (Abbv-075) to replicate kidney senescence in vivo. D-gal and Abbv-075 were then used to measure the aging-related changes, such as changes in cell cycle, β-galactosidase activity, cell migration, and p16 protein expression in vitro. At last, we knocked down and over-expressed BRD4 to investigate the aging-related physiological phenomena in renal tubular cells.In vitro, D-gal treatment induced noticeable aging-related changes such as inducing cell apoptosis and cell cycle arrest, increasing β-galactosidase activity as well as up-regulating p16 protein expression in primary human tubular epithelial cells. In the aging mice model, D-gal significantly induced renal function impairment and attenuated BRD4 protein expression. At the same time, the BRD4 inhibitor (Abbv-075) was able to mimic D-gal-induced cell senescence. In vivo, Abbv-075 also decreased kidney function and up-regulated p21 protein expression. When we knocked down the expression of BRD4, the senescence-associated β-galactosidase (SA-β-gal) activity increased dramatically, cell migration was inhibited, and the proportion of cells in the G0/G1 phase increased. Additionally, the knockdown also promoted the expression of the senescence-related proteins p16. When the renal tubular cells were overexpressed with BRD4, cell aging-related indicators were reversed in the D-gal-induced cell aging model.BRD4 appears to have an active role in the aging of renal tubular cells in vivo and in vitro. The findings also suggest that BRD4 inhibitors have potential nephrotoxic effects for oncology treatment. BRD4 may be a potential therapeutic biomarker and drug target for aging-related kidney diseases, which warrants additional studies.2024 Translational Andrology and Urology. All rights reserved.