The gut microbiota instructs the hepatic endothelial cell transcriptome

The gut microbiota affects remote organ functions but its impact on organotypic endothelial cell (EC) transcriptomes remains unexplored. The liver endothelium encounters microbiota-derived signals and metabolites via the portal circulation. To pinpoint how gut commensals affect the hepatic sinusoidal endothelium, a magnetic cell sorting protocol, combined with fluorescence activated cell sorting, was used to analyze the transcriptome of hepatic sinusoidal ECs from germ-free (GF) and conventionally-raised (CONV-R) mice by RNA-sequencing. This resulted in a comprehensive map of microbiota-regulated hepatic EC-specific transcriptome profiles. Gene Ontology analysis revealed that several functional processes in the hepatic endothelium were influenced. The absence of a microbiota influenced the expression of genes involved in cholesterol flux and angiogenesis. Specifically, genes functioning in hepatic endothelial sphingosine matabolism and the sphingosine-1-phosphate pathway showed a drastically increased expression in the GF state. Our analyses reveal a prominent role for the microbiota in shaping the transcriptional landscape of the hepatic endothelium. Overall design: Transcriptome analysis of hepatic sinusoidal ECs from germ-free (GF) and conventionally-raised (CONV-R) mice by RNA-sequencing