4-Methylenesterols from Theonella swinhoei sponge are natural pregnane-X-receptor agonists and farnesoid-X-receptor antagonists that modulate innate immunity

We report the isolation and the structural elucidation of a family of polyhydroxylated steroids from the marine sponge Theonella swinhoei. Decodification of interactions of these family with nuclear receptors shows that these steroids are potent agonists of human pregnane-X-receptor (PXR) and antagonists of human farnesoid-X-receptor (FXR) with the putative binding mode to nuclear receptors (NRs) obtained through docking experiments.By using monocytes isolated from transgenic mice harboring hPXR, we demonstrated that swinhosterol B counter-regulates induction of pro-inflammatory cytokines in a PXR-dependent manner. Exposure of CD4+ T cells to swinhosterol B upregulates the expression of IL-10 causing a shift toward a T cells regulatory phenotype in a PXR dependent manner. These results pave the way to development of a dual PXR agonist/FXR antagonist with a robust immunomodulatory activity and endowed with the ability to modulate the expression of bile acid-regulated genes in the liver.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Structural elucidation of polyhydroxylated steroids from the marine sponge Theonella swinhoei. ► Discovery of potent agonists of PXR and antagonists of FXR. ► The putative binding mode to nuclear receptors (NRs) has been obtained through docking calculations. ► Swinhosterol B counter-regulates induction of pro-inflammatory cytokines in a PXR-dependent manner.