Abstract

This study investigated the regulatory role of CCL2 in traumatic brain injury (TBI) and elucidated its underlying molecular mechanism. Bioinformatics analysis revealed significant enrichment of CCL2 in the TNF signaling pathway. ELISA and Western blot analyses confirmed marked upregulation of CCL2 in the serum of TBI patients as well as in the serum and brain tissues of TBI mouse models. Functional experiments demonstrated that CCL2 knockdown significantly alleviated neurological impairment and secondary brain injury in TBI mice. Mechanistically, CCL2 suppression enhanced neuronal autophagy, as evidenced by increased Beclin1 and LC3-II expression and modulation of autophagy flux markers (p62 and LAMP2), while simultaneously attenuating neuronal apoptosis through regulation of apoptosis-related proteins, including Bcl-2, Bax, and cleaved caspase-3. Rescue experiments further showed that TNFR1 overexpression abolished the protective effects of CCL2 knockdown and restored activation of the TNF signaling pathway, accompanied by elevated MCP-1, TNFR1, and phosphorylated p65 levels. Collectively, these findings demonstrate that CCL2 promotes TBI progression by activating the TNF signaling pathway, thereby suppressing autophagy and enhancing apoptosis. Targeting the CCL2–TNFR1 axis may represent a promising therapeutic strategy for secondary brain injury following TBI.