Conventional type 1 dendritic cells protect against gut barrier disruption via maintaining Akkermansia muciniphila in alcoholic steatohepatitis

Alcohol-perturbed gut immune homeostasis is associated with the development of alcoholic liver disease (ALD). However, the role of intestinal dendritic cells (DCs) in ALD progression is still unknown. This study aimed to investigate the cellular and molecular mechanisms through which intestinal DCs respond to alcohol exposure and contribute to the pathogenesis of ALD.After 8 weeks of alcohol consumption, the number of basic leucine zipper transcription factor ATF-like 3 ( Batf3 )-dependent conventional type 1 DCs (cDC1s) was dramatically decreased in the intestine but not the liver. cDC1 deficient Batf3 knockout mice along with wild-type mice were subjected to chronic-binge ethanol feeding to determine the role of intestinal cDC1s reduction in ALD. cDC1s deficiency exacerbated alcohol-induced gut barrier disruption, bacterial endotoxin translocation into the circulation, and liver injury. Adoptive transfer of cDC1s to alcohol-fed mice ameliorated alcohol-mediated gut barrier dysfunction and liver injury. Further studies revealed that intestinal cDC1s serve as a positive regulator of Akkermansia muciniphila ( A. muciniphila ). Oral administration of A. muciniphila markedly reversed alcoholic steatohepatitis in mice. Mechanistic studies revealed that cDC1s depletion exacerbated alcohol-downregulated intestinal antimicrobial peptides which play a crucial role in maintaining A. muciniphila abundance, by disrupting the IL-12-interferon gamma signaling pathway. Lastly, we identified that intestinal cDC1s were required for the protective role of Lactobacillus reuteri in alcoholic steatohepatitis.This study demonstrated that cDC1s protect alcohol-induced liver injury by maintaining A. muciniphila abundance in mice. Targeting cDC1s may serve as a promising therapeutic approach for treating ALD.