Division of Nephrology and National Clinical Research Center for Geriatrics, Kidney Research Institute, West China Hospital of Sichuan University, Chengdu 610041, China.
West China Biomedical Big Data Center, West China Hospital of Sichuan University, Chengdu 610041, China.
Life Sci. 2021 Mar 1;268:119023. doi: 10.1016/j.lfs.2021.119023. Epub 2021 Jan 9.
AIMS: Rhabdomyolysis-associated acute kidney injury (AKI) is life-threatening but effective treatments is lacking. Recently, fatty acid-binding protein 4 (FABP4) has been identified as a mediator of ischemic and toxic AKI through regulating endoplasmic reticulum (ER) stress in our previous studies. However, the role of FABP4 in rhabdomyolysis-induced AKI and extended organelle dysfunctions need to be explored and validated. MAIN METHODS: We firstly performed mRNA-seq and bioinformatic analysis to investigate the role of FABP4. The mouse model was established via injecting glycerol to FABP4 wild type (WT) and knockout (KO) mice. Blood biochemical, inflammatory and apoptotic parameters were measured and compared across groups. Representative pathways of ER stress and mitochondrial dysfunction were also detected and quantified. KEY FINDINGS: Comparing FABP4 WT and FABP4 KO model groups, FABP4 deficiency significantly attenuated renal dysfunction, by reducing serum creatinine (165.90 ± 15.61 μmol/L vs 35.5 ± 8.33 μmol/L, p < 0.0001) and blood urea nitrogen (89.78 ± 6.82 mmol/L vs 19.75 ± 5.97 mmol/L, p < 0.0001), and alleviating tubular injury scores. Inflammatory and apoptotic responses were alleviated by FABP4 genetic inhibition. Mechanistically, glycerol injection triggered ER stress characterized by activated IRE1, PERK, and ATF6 signaling pathways, and induced mitochondrial dysfunction supported by ultrastructural damage, energy metabolic derangement, and excessive mitochondrial fission (upregulated DRP1/downregulated OPA1). These two organelle dysfunctions were effectively relieved by FABP4 deficiency. SIGNIFICANCE: Taken together, genetic inhibition of FABP4 protected against rhabdomyolysis-induced AKI via reducing ER stress as well as mitochondrial dysfunction. FABP4 might act as a novel therapeutic target in rhabdomyolysis-induced AKI.
目的:横纹肌溶解相关性急性肾损伤(AKI)具有生命威胁,但目前缺乏有效的治疗方法。最近,我们的研究发现脂肪酸结合蛋白 4(FABP4)可通过调节内质网(ER)应激,成为缺血性和毒性 AKI 的介质。然而,FABP4 在肌溶解诱导的 AKI 及扩展的细胞器功能障碍中的作用仍需进一步探索和验证。
主要方法:我们首先进行了 mRNA-seq 和生物信息学分析,以研究 FABP4 的作用。通过向 FABP4 野生型(WT)和敲除(KO)小鼠注射甘油来建立小鼠模型。测量并比较各组的血液生化、炎症和凋亡参数。还检测和量化了 ER 应激和线粒体功能障碍的代表性途径。
主要发现:与 FABP4 WT 模型组相比,FABP4 缺失显著减轻了肾功能障碍,降低了血清肌酐(165.90±15.61μmol/L 比 35.5±8.33μmol/L,p<0.0001)和血尿素氮(89.78±6.82mmol/L 比 19.75±5.97mmol/L,p<0.0001),并减轻了肾小管损伤评分。炎症和凋亡反应也因 FABP4 的遗传抑制而减轻。在机制上,甘油注射引发了以 IRE1、PERK 和 ATF6 信号通路激活为特征的 ER 应激,并通过超微结构损伤、能量代谢紊乱和过度线粒体分裂(DRP1 上调/OPA1 下调)支持的线粒体功能障碍。这两种细胞器功能障碍均因 FABP4 缺失而得到有效缓解。
意义:总之,FABP4 的遗传抑制通过减轻 ER 应激和线粒体功能障碍,防止了肌溶解诱导的 AKI。FABP4 可能成为肌溶解诱导的 AKI 的一种新的治疗靶点。
JMIR Public Health Surveill. 2023-5-4