ELMO1 and Rac1 Signaling in Kidney Disease: Molecular Mechanisms, Context-Dependent Roles, and Therapeutic Potential

Background: Chronic kidney disease (CKD) is a major global health burden, affecting more than 850 million people worldwide. Increasing evidence implicates engulfment and cell motility 1 (ELMO1), a cytoplasmic adaptor protein that regulates cytoskeletal remodeling, phagocytosis, and immune responses through the ELMO1-DOCK1-Rac1 signaling axis, in renal injury and disease progression. Methods: This narrative review identified relevant publications through searches of PubMed, Web of Science, and Google Scholar using combinations of the terms "ELMO1," "kidney disease," "diabetic kidney disease," "IgA nephropathy," "focal segmental glomerulosclerosis," "acute kidney injury," and "renal fibrosis." English-language original research articles, genetic association studies, mechanistic investigations, and selected review articles were preferentially included according to their relevance to ELMO1 in kidney diseases. Results: Genetic association studies have implicated the ELMO1 locus in susceptibility to diabetic kidney disease (DKD), although associated variants and effect sizes differ across populations. Experimental studies suggest that ELMO1 regulates cytoskeletal remodeling, inflammatory responses, oxidative stress, and extracellular matrix deposition through the canonical ELMO1-DOCK1-Rac1 signaling pathway as well as Rac1-independent mechanisms. Available evidence supports a role for ELMO1 in DKD and renal fibrotic remodeling. In focal segmental glomerulosclerosis, the relevance of ELMO1 is primarily inferred from Rac1-associated podocyte injury pathways, whereas evidence in acute kidney injury remains limited and context-dependent. ELMO1 may contribute to inflammatory injury in ischemia-reperfusion settings but may also support efferocytosis and tissue repair in nephrotoxic injury models. In IgA nephropathy, evidence for a direct role of ELMO1 remains limited and is currently based largely on indirect mechanistic observations involving mucosal immunity and glomerular injury responses. Conclusions: ELMO1 is a context-dependent regulator of cytoskeletal, inflammatory, oxidative, and matrix-remodeling processes relevant to kidney disease. The strongest evidence currently supports its involvement in DKD, whereas its roles in other kidney diseases remain to be further defined in disease-specific, cell-type-specific, and stage-specific experimental models. Further studies are required to clarify its potential as a biomarker or therapeutic target in CKD.