Background: Acute liver injury (ALI) can rapidly progress to life-threatening acute liver failure. Liver transplantation remains the only definitive treatment, despite critical donor shortages. Macrophage-based therapies have shown promise in ALI but face challenges related to subset imprecision and limited humanized validation. VSIG4 is generally considered a marker of Kupffer cells; however, it is also expressed in monocyte-derived macrophages (MoMFs), and its role remains unclear during ALI.
Methods: By integrating single-cell RNA sequencing (scRNA-seq) data from human and mouse liver tissues with clinical ALI tissue samples, we elucidated the dynamic changes in VSIG4+ macrophages (VSIG4+ Mφ) within the liver. We developed a reversible immunomagnetic nanoparticle system for the non-destructive isolation of viable VSIG4+ Mφ. The therapeutic efficacy and potential mechanisms of VSIG4+ Mφ were evaluated through tissue and molecular-level analyses in an acetaminophen (APAP)-induced ALI mouse model, as well as in a newly established vascularized human liver organoid ALI and monocyte chemotaxis model.
Results: scRNA-seq revealed a previously underrecognized subpopulation of VSIG4+ MoMFs, which increases following ALI, while the number of resident VSIG4+ Kupffer cells decreases significantly. Clinical ALI tissue samples also confirmed the presence of CCR2+VSIG4+ cells in the livers of patients with ALI. In the APAP-induced ALI animal model, adoptive transfer of isolated VSIG4+ MoMFs dramatically decreased serum alanine transaminase, hepatic necrosis, and apoptosis while increasing anti-inflammatory cytokines. In contrast, adoptive transfer of unselected BMDM failed to improve liver injury and instead exacerbated certain pro-inflammatory responses, including elevated TNF-α and reduced CD206 expression. Mechanistically, VSIG4+ MoMFs prevented inflammatory amplification by suppressing NF-κB-dependent CCL2 transcription, thereby disrupting the CCL2-CCR2 chemotactic axis and reducing pro-inflammatory CCR2+ monocyte and macrophage recruitment. We further developed vascularized human liver organoids and APAP-induced hepatocyte injury and monocyte chemotaxis, finding that the chemotaxis-interrupting mechanism was fully recapitulated in the human liver organoid ALI model.
Discussion: This study identifies VSIG4+ MoMFs as a therapeutically viable subset for ALI, with clear superiority over unselected BMDM. By blocking the CCL2-CCR2 inflammatory amplification loop, these cells attenuate liver injury in both mouse and humanized models. These consistent findings provide robust preclinical evidence to support the advancement of VSIG4+ Mφ-based immunotherapies into clinical practice.
Keywords: Acute liver injury; Adoptive cell therapy; CCL2-CCR2 axis; Chemotaxis; Human liver organoids; VSIG4+ macrophages.
PMID: 42477763
PMCID: PMC13386671
