Regulation mechanism of ischemic preconditioning renal tubular cell-derived exosomes on PI3K/AKT/mTOR signaling pathway in rats with renal ischemia reperfusion injury
10.3760/cma.j.cn441217-20231006-01004
- VernacularTitle:缺血预处理的肾小管细胞来源外泌体对肾缺血再灌注损伤大鼠PI3K/AKT/mTOR信号通路的调控机制
- Author:
Jiahui CHEN
1
;
Yanzi ZHANG
;
Aisha ZHANG
;
Xiaolu SUI
;
Yunpeng XU
;
Tingfei XIE
;
Jihong CHEN
Author Information
1. 广东医科大学深圳宝安临床医学院肾内科，深圳518000
- Keywords:
Exosomes;
MicroRNAs;
Reperfusion injury;
Phosphatidylinositol 3-kinases;
PI3K/AKT/mTOR
- From:
Chinese Journal of Nephrology
2024;40(9):732-740
- CountryChina
- Language:Chinese
-
Abstract:
This study aims to establish a rat model of renal ischemia reperfusion injury (RIRI) to observe the alterations in the expression of phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway following various exosome treatments. Additionally, differential miRNA expression analysis will be conducted to elucidate the molecular mechanisms underlying the effects of exosomes derived from ischemic preconditioned (IPC) renal tubular cells in mitigating RIRI in rats. Initially, ten SD rats were subjected to bilateral nephrectomy under general anesthesia to prepare primary renal tubular cells. The second-generation renal tubular cells were then subjected to the following treatments for 12 hours: normoxia (38% O 2, 5% CO 2), hypoxia (1% O 2, 5% CO 2), and hypoxia plus inactivation (heated at 65 ℃ for 30 minutes). Following these treatments, exosomes were extracted, yielding normoxic exosomes, IPC exosomes, and inactivated exosomes, respectively. A subsequent cohort of 50 SD rats was randomly divided into five groups: Sham group, RIRI group, RIRI + normoxic exosome group (NC group), RIRI + IPC exosome group (IPC group), and RIRI + inactivated exosome group (INA group). RIRI model was established in the latter four groups. Twenty-four hours after RIRI modeling, the NC, IPC, and INA groups received intravenous injections of 200 μg of normoxic exosomes, IPC exosomes, and inactivated exosomes via the tail vein, respectively. Six days later, venous blood samples were collected, and both kidneys were excised to observe renal function, histopathological changes in kidney tissue, and alterations in the PI3K/AKT/mTOR signaling pathway among the five groups. Furthermore, differential miRNA expression analysis [ P<0.05, |log 2(Fold Change)|≥1] was conducted between the NC and IPC groups to investigate the changes in the miRNA expression profile. Subsequently, GO analysis and KEGG pathway enrichment analysis were performed. The results revealed that: (1) Compared with the Sham group, the RIRI and INA groups exhibited elevated levels of serum creatinine and urea nitrogen (all P<0.01). Histopathological examination of kidney tissues showed substantial inflammatory cell infiltration in the interstitium accompanied by varying degrees of edema, degenerative swelling of tubular structures, necrosis, and detachment of tubular epithelial cells. Notably, the number of TUNEL-positive cells was significantly increased, while the number of Ki67-stained positive cells was markedly decreased. Additionally, the mRNA and protein expression of PI3K/AKT/mTOR signaling pathway in RIRI group and INA group were down-regulated. (2) Compared to the NC group, the IPC group demonstrated lower levels of serum creatinine and urea nitrogen (both P<0.01). Notably, there was a significant decrease in the accumulation of inflammatory cells in the renal interstitium, and tissue edema was markedly improved. Moreover, the number of TUNEL-positive cells was reduced, while the number of Ki67-stained positive cells was significantly increased. Additionally, the mRNA and protein expressions of PI3K, PDK1, AKT, and mTOR were all up-regulated (all P<0.05). (3) Compared to the NC group, 56 miRNAs were up-regulated and 42 miRNAs were down-regulated in the IPC group. The target genes of GO enrichment analysis were PIK3C2A, PIK3CA, PIK3CB, PIK3CD, PIK3C2G, AKT1, mTOR, Rheb, and KEGG enrichment analysis revealed significant enrichment in PI3K/AKT signal pathway and mTOR signal pathway. In conclusion, this study reveals that during the course of RIRI, exosomes derived from IPC renal tubular cells induce differential miRNA expression in kidney tissues, resulting in enhanced expression of the PI3K/AKT/mTOR signaling pathway, which plays a pivotal role in mitigating RIRI in rats.
