Identification of Natural RORγ Ligands that Regulate the Development of Lymphoid Cells

• DOI: 10.1016/j.cmet.2015.01.004
• Publication Date: 2015-02-03T17:31:36Z
• Authors: Fabio R. Santori; Pengxiang Huang; Serge A. van de P...; Eugene F. Douglass; David J. Leaver; Brad A. Haubrich; Rok Keber; Gregor Lorbek; Tanja Konijn; Brittany N. Rosales; Damjana Rozman; Simon Horvat; Alain Rahier; Reina E. Mebius; Fraydoon Rastinejad; W. David Nes; Dan R. Littman
• Keywords: Male; 0301 basic medicine; Physiology; [SDV]Life Sciences [q-bio]; Mice, Transgenic; [SDV.BC]Life Sciences [q-bio]/Cellular Biology; [SDV.BBM.BM] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology; Ligands; Cell Line; Mice; Sterol 14-Demethylase; 03 medical and health sciences; Animals; Humans; Lymphocytes; Molecular Biology; [SDV.BC] Life Sciences [q-bio]/Cellular Biology; Mice, Knockout; [SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology; Cell Biology; Nuclear Receptor Subfamily 1, Group F, Member 3; [SDV] Life Sciences [q-bio]; Sterols; Cholesterol; Drosophila melanogaster; HEK293 Cells; Th17 Cells

Mice deficient in the nuclear hormone receptor RORγt have defective development of thymocytes, lymphoid organs, Th17 cells, and type 3 innate lymphoid cells. RORγt binds to oxysterols derived from cholesterol catabolism, but it is not clear whether these are its natural ligands. Here, we show that sterol lipids are necessary and sufficient to drive RORγt-dependent transcription. We combined overexpression, RNAi, and genetic deletion of metabolic enzymes to study RORγ-dependent transcription. Our results are consistent with the RORγt ligand(s) being a cholesterol biosynthetic intermediate (CBI) downstream of lanosterol and upstream of zymosterol. Analysis of lipids bound to RORγ identified molecules with molecular weights consistent with CBIs. Furthermore, CBIs stabilized the RORγ ligand-binding domain and induced coactivator recruitment. Genetic deletion of metabolic enzymes upstream of the RORγt-ligand(s) affected the development of lymph nodes and Th17 cells. Our data suggest that CBIs play a role in lymphocyte development potentially through regulation of RORγt.