The CXCL12/CXCR4 Axis in Sepsis-Induced Acute Lung Injury: Mechanisms and Therapeutic Potential

Sepsis remains a major cause of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), conditions characterized by high mortality and limited therapeutic options. Among the diverse inflammatory pathways implicated in their pathogenesis, the CXCL12/CXCR4 chemokine axis has gained increasing attention for its dual capacity to drive acute inflammation while also supporting tissue repair. Although numerous studies have investigated this signaling pathway, an integrated framework that reconciles its context-dependent functions, upstream regulatory mechanisms, and translational relevance has been lacking. In this review, we synthesize current evidence on the multifaceted roles of the CXCL12/CXCR4 axis in sepsis-induced ALI, highlighting its cell-type-specific effects in neutrophils, macrophages, alveolar epithelial cells, and endothelial cells through downstream pathways such as NF-κB, MAPK, and PI3K/Akt. We further evaluate emerging therapeutic approaches, including small-molecule antagonists (e.g., AMD3100), natural products, and epigenetic modulators. Newly added sections summarize the upstream regulation of CXCL12 by hypoxia, cytokines, and epigenetic factors, discuss the regulatory influence of the alternative receptor CXCR7/ACKR3, and differentiate preclinical insights from human clinical observations. Finally, we outline key obstacles to clinical translation and propose future directions to develop precision medicine strategies that more effectively target this axis. Collectively, our analysis suggests that although the CXCL12/CXCR4 pathway represents a promising target for ALI/ARDS therapy, its context-dependent and cell-specific actions demand carefully tailored modulation rather than uniform inhibition.