HNRNPC-Mediated m6A Epitranscriptomics Drives CD80-Dependent Tubular Dysfunction in Sepsis-Induced AKI

Sepsis-associated acute kidney injury (S-AKI) is a critical condition characterized by renal tubular epithelial cell apoptosis and abnormal cytoskeleton. This study aims to investigate the role of the m6A modification-dependent protein HNRNPC in regulating renal cell apoptosis and cytoskeleton in S-AKI. Dot blot analysis was employed to assess the total m6A levels. Cell viability, flow cytometry, and fluorescent phalloidin staining were used to evaluate the role of HNRNPC in CD80-dependent apoptosis and cytoskeletal remodeling. RNA sequencing and subsequent data analysis highlighted the involvement of the NF-κB signaling pathway. Luciferase reporter assays and Western blot were used to establish that HNRNPC transcriptionally promotes CD80 expression. Bioinformatics, EMSA, and ChIP assays further confirmed the role of NF-κB in regulating CD80. Additionally, MeRIP-qPCR and RNA m6A quantification demonstrated that HNRNPC facilitates apoptosis through m6A-dependent regulation of NF-κB. Induction of HNRNPC to a higher level can induce apoptosis and cytoskeletal deformation in renal tubular cells. Meanwhile, CD80 was essential for HNRNPC-induced tubular injury. Further experiments showed that HNRNPC regulated NF-κB mRNA dependent on m6A modification. Moreover, NF-κB acted as a transcription factor to promote CD80 expression. In vivo experiments further verified the relationships between HNRNPC, NF-κB, and CD80 and demonstrated the significance of HNRNPC in CD80-associated apoptosis. This study elucidates the molecular mechanisms underlying the pathogenesis of S-AKI and highlights the potential of HNRNPC and CD80 as therapeutic targets to reduce renal damage in S-AKI.