Single-cell profiling uncovers kaempferol-mediated immunoregulation in the protection against experimental autoimmune hepatitis.

BACKGROUND

Autoimmune hepatitis (AIH) is triggered by an aberrant immune response directed against hepatocyte autoantigens, ultimately leading to liver inflammation and hepatocellular damage. Kaempferol (KAE), a natural flavonoid, exhibits potent anti-inflammatory and hepatoprotective properties. However, the precise immunoregulatory mechanisms of KAE in alleviating AIH are still undefined.

OBJECTIVES

This study utilized comprehensive single-cell analysis to investigate the therapeutic efficacy and underlying immunoregulatory mechanisms of KAE in alleviating ConA-induced experimental AIH.

METHODS

Murine AIH models were established by concanavalin A (ConA) injection. The serum cytokine levels were measured using antibody microarray. Cytometry by time-of-flight (CyTOF) and single-cell RNA sequencing (scRNA-seq) were employed to thoroughly examine the high-dimensional immune landscape at single-cell resolution. Multiple immunofluorescence assays were carried out to achieve in situ co-localization of the key markers.

RESULTS

KAE treatment significantly mitigated ConA-induced experimental AIH and reshaped the hepatic immune microenvironment. Comprehensive single-cell analysis revealed that KAE maintained hepatocyte homeostasis. Additionally, KAE promoted the expansion of M2 macrophages and upregulated Acod1, a key enzyme for itaconate synthesis, suggesting an anti-inflammatory effect of macrophages following KAE treatment. Furthermore, KAE significantly depleted pathogenic CD8+ resident memory T cells (Trm) and CD8+ central memory T cells (Tcm), probably through upregulation of Klf2 in CD8+ Tcm cells to inhibit lymphocyte tissue residency and induction of apoptosis in both pathogenic CD8+ Tcm and CD8+ Trm subsets.

CONCLUSION

This study demonstrated protective efficacy of KAE against AIH, providing novel insights for immunomodulatory therapy.