IRF1-Regulated CCL25/CCR9 Promotes Chronic Kidney Disease Progression Through PI3K/AKT-Mediated Oxidative Stress and Inflammatory Response

Abstract

Chronic kidney disease (CKD) is imperceptible and with a complex pathogenesis involving oxidative stress and inflammatory responses. The phosphatidylinositol 3 kinases/protein kinase B (PI3K/AKT) signaling pathway plays a crucial role in this process. Previous studies indicated that chemokine ligand 25 (CCL25) and its receptor CCR9 participate in regulating the PI3K/AKT pathway. However, it remains unclear whether CCL25/CCR9 influences CKD by modulating oxidative stress and inflammation via the PI3K/AKT pathway. We aimed to clarify the roles of CCL25/CCR9 in CKD progression through PI3K/AKT activation and its upstream regulatory factors. In this study, an adenine-induced CKD rat model and an indoxyl sulfate-induced CKD cell model were constructed. Bioinformatics method based on two online websites (JASPAR and Cistrome DB) was conducted to predict the upstream of CCL25/CCR9. Anti-CCL25 and PI3K/AKT activator 740Y-P were added, and sh-IRF1 was transfected into the HK-2 cells for the mechanism exploration. Renal function markers (blood urea nitrogen, creatinine, urine protein/creatinine ratio), renal pathology, oxidative stress markers (reactive oxygen species, malondialdehyde, superoxide dismutase), inflammatory cytokines (Interleukin (IL)-1β, IL-6, Tumor Necrosis Factor (TNF)-α), and the expression of CCL25, CCR9, PI3K/AKT pathway-related proteins, and the transcription factor interferon regulatory factor 1 (IRF1) were measured. Chromatin immunoprecipitation PCR (ChIP-PCR) was used to confirm IRF1 binding to the CCL25 promoter. The results indicated that CCL25 and CCR9 were upregulated in CKD rat and in vitro cell model. Enhanced oxidative stress and inflammatory response, followed by renal fibrosis and renal dysfunction, were observed in CKD rats. Anti-CCL25 addition decreased the PI3K/AKT markers, oxidative stress markers, and inflammatory responses, whereas 740Y-P addition reversed the above alteration. IRF1 was confirmed to be an important transcription factor for CCL25 in bioinformatics analysis. IRF1 was increased in CKD models and binding with CCL25 in ChIP-PCR detection. sh-IRF1 transfection decreased the CCL25 and CCR9 expression. In conclusion, IRF1-regulated CCL25/CCR9 was demonstrated to promote CKD progression through PI3K/AKT-mediated oxidative stress and inflammatory response.