Regulation of calcium homeostasis by S100A12 drives NETosis in chronic kidney disease.

Chronic kidney disease (CKD) is characterized by persistent renal injury and inflammation. Although S100A12 is associated with inflammatory states, its specific role in regulating neutrophil extracellular trap (NET) formation (NETosis) and contributing to renal pathology in CKD remains poorly understood. This study aimed to identify key diagnostic biomarkers and elucidate the mechanism by which S100A12 mediates NETosis in CKD. METHODS: Integrated bioinformatic analysis was performed on combined datasets (GSE37171, GSE66494, and GSE15072). Differentially expressed genes (DEGs) were screened using WGCNA and three machine learning algorithms (LASSO, SVM-RFE, and Random Forest) to identify hub genes. Immune infiltration was analyzed to assess immune cell proportions. Clinical validation was conducted using peripheral blood samples from 43 CKD patients and 17 healthy controls collected between July 2024 and January 2025. Furthermore, in vitro experiments using dHL-60 cells investigated the impact of S100A12 on NET formation and calcium signaling. RESULTS: We identified 622 DEGs significantly expressed in CKD and enriched in inflammatory regulation. Five hub genes (MMP11, CASR, GATA1, MMP7, and S100A12) were identified, yielding a diagnostic model with high accuracy (AUC = 0.940). Immune infiltration analysis revealed that S100A12 expression was positively correlated with neutrophil infiltration. Experimental validation confirmed significantly elevated levels of S100A12 and NETosis markers (PADI4, MPO, dsDNA, and MPO-DNA complexes) in CKD patients compared to controls. Studies in dHL-60 cells demonstrated that S100A12 overexpression promotes NETosis via calcium overload, a process effectively inhibited by the calcium channel blocker verapamil. CONCLUSIONS: Integrated bioinformatic and experimental analyses identify S100A12 as a robust diagnostic biomarker and a key mediator of NETosis in CKD. Targeting the S100A12-mediated calcium signaling pathway offers a promising future direction for mitigating renal inflammation and injury..