Project description:T helper 17 (Th17) cells produce interleukin-17 (IL-17) cytokines and drive inflammatory responses in autoimmune diseases such as multiple sclerosis and rheumatoid arthritis. The differentiation of Th17 cells is dependent on the retinoic acid receptor-related orphan nuclear receptor RORgt. Here we identify REV-ERBa (encoded by Nr1d1), a member of the nuclear hormone receptor family (NHR), as a transcriptional repressor that antagonizes RORgt function in Th17 cells. REV-ERBa binds to ROR response elements (RORE) in Th17 cells and inhibits the expression of RORgt-dependent genes such as Il17a and Il17f. Furthermore, elevated REV-ERBa expression or treatment with a synthetic REV-ERB agonist significantly delays the onset and impedes the progression of experimental autoimmune encephalomyelitis (EAE), a Th17 cell-mediated autoimmune disease. These results suggest that modulating REV-ERB activity may hold therapeutic potential for treatment of Th17 cell-mediated autoimmune diseases.
Project description:RORγt is well recognized as the lineage defining transcription factor for TH17 cell development. However, the cell-intrinsic mechanisms that negatively regulate TH17 cell development and autoimmunity remain poorly understood. Here we demonstrate that the transcriptional repressor REV-ERBa is exclusively expressed in TH17 cells, competes with RORγt for their shared DNA consensus sequence, and negatively regulates TH17 cell development via repression of genes traditionally characterized as RORγt-dependent, including Il17a. Deletion of REV-ERBa enhanced TH17-mediated pro-inflammatory cytokine expression, exacerbating experimental autoimmune encephalomyelitis (EAE) and colitis. Treatment with REV-ERB-specific synthetic ligands, which have similar phenotypic properties as RORγ modulators, suppressed TH17 cell development, was effective in colitis intervention studies, and significantly decreased the onset, severity, and relapse rate in several models of EAE without affecting thymic cellularity. Our results establish that REV-ERBa negatively regulates pro-inflammatory TH17 responses in vivo and identifies the REV-ERBs as potential targets for the treatment of TH17-mediated autoimmune diseases.
Project description:The circadian nature of mood and its dysfunction in affective disorders is well recognized, but the underlying molecular mechanisms are still unclear. We showed that the circadian nuclear receptor REV-ERBa, which is associated with bipolar disorder, impacts midbrain dopamine production and mood-related behavior in mice. Genetic deletion of the Rev-erba gene or pharmacological inhibition of REV-ERBa activity in the ventral midbrain induced mania-like behavior in association with a central hyperdopaminergic state. We used microarrays to identify differentially expressed genes in the ventral midbrains of wild-type (WT) and Rev-erba knock-out (RKO) mice.
Project description:Circadian gene transcription is fundamental to metabolic physiology. Here we report that the nuclear receptor REV-ERBa, a repressive component of the molecular clock, forms circadian condensates in the nuclei of mouse liver. These condensates are dictated by an intrinsically disordered region (IDR) located in the protein’s hinge region which specifically concentrates nuclear receptor corepressor 1 (NCOR1) at the genome. IDR deletion diminishes the recruitment of NCOR1 and disrupts rhythmic gene transcription in vivo. REV-ERBa condensates are located at high-order transcriptional repressive hubs in the liver genome that are highly correlated with circadian gene repression. Deletion of the IDR disrupts transcriptional repressive hubs and diminishes silencing of target genes by REV-ERBa. This work demonstrates physiological circadian protein condensates containing REV-ERBa whose IDR is required for hub formation and the control of rhythmic gene expression.
Project description:RORgt is known to instruct the differentiation of Th17 cells that mediate the pathogenesis of autoimmune diseases. However, it remains unknown whether RORgt plays a distinct role in the differentiation and effector function of Th17 cells. Here we show that mutation of RORgt lysine 256, a ubiquitination site, to arginine (K256R) separates the RORgt role in these two functions. Preventing ubiquitination at K256 via arginine substitution does not affect RORgt-dependent thymocyte development and Th17 differentiation in vitro and in vivo, however, greatly impaired the pathogenesis of Th17 cell-mediated experimental autoimmune encephalomyelitis (EAE). Mechanistically, K256R mutation impairs RORgt to bind to and activate Runx1 expression critical for Th17-mediated EAE. Thus, RORgt regulates the effector function of Th17 cells in addition to Th17 differentiation. This work informs the development of RORgt-based therapies that specifically target the effector function of Th17 cells responsible for autoimmunity.
Project description:RORgt is known to instruct the differentiation of Th17 cells that mediate the pathogenesis of autoimmune diseases. However, it remains unknown whether RORgt plays a distinct role in the differentiation and effector function of Th17 cells. Here we show that mutation of RORgt lysine 256, a ubiquitination site, to arginine (K256R) separates the RORgt role in these two functions. Preventing ubiquitination at K256 via arginine substitution does not affect RORgt-dependent thymocyte development and Th17 differentiation in vitro and in vivo, however, greatly impaired the pathogenesis of Th17 cell-mediated experimental autoimmune encephalomyelitis (EAE). Mechanistically, K256R mutation impairs RORgt to bind to and activate Runx1 expression critical for Th17-mediated EAE. Thus, RORgt regulates the effector function of Th17 cells in addition to Th17 differentiation. This work informs the development of RORgt-based therapies that specifically target the effector function of Th17 cells responsible for autoimmunity.
Project description:The circadian nature of mood and its dysfunction in affective disorders is well recognized, but the underlying molecular mechanisms are still unclear. We showed that the circadian nuclear receptor REV-ERBa, which is associated with bipolar disorder, impacts midbrain dopamine production and mood-related behavior in mice. Genetic deletion of the Rev-erba gene or pharmacological inhibition of REV-ERBa activity in the ventral midbrain induced mania-like behavior in association with a central hyperdopaminergic state. We used microarrays to identify differentially expressed genes in the ventral midbrains of wild-type (WT) and Rev-erba knock-out (RKO) mice. Male RKO and WT mice (10-15 weeks of age) were maintained in a C57BL/6J background. Mice were housed in temperature-controlled (22-23ºC) quarters under a 12-h light-dark (LD) photoperiod (lights on at 8:00 a.m.). After entrainment for >10 days under LD conditions, mice were kept in constant darkness (DD) for 2 days starting at lights-off time. On the third day, mice were sacrificed at indicated time points by cervical dislocation.
Project description:The circadian clock regulates behavioural and physiological processes in a 24-h cycle. The nuclear receptors REV-ERBa and REV-ERBb are involved in the cell-autonomous circadian transcriptional/translational feedback loops as transcriptional repressors. A number of studies have also demonstrated a pivotal role of REV-ERBs in regulation of metabolic, neuronal, and inflammatory functions including bile acid metabolism, lipid metabolism, and production of inflammatory cytokines. Given the multifunctional role of REV-ERBs, it is important to elucidate the mechanism through which REV-ERBs exert their functions. To this end, we established a Rev-erba/Rev-erbb double-knockout mouse embryonic stem (ES) cell model and analyzed the circadian clock and clock-controlled output gene expressions. A comprehensive mRNA-seq analysis revealed that the complete knockout of both Rev-erba and Rev-erbb does not abrogate expression rhythms of E-box-regulated core clock genes but drastically changes a diverse set of other rhythmically-expressed output genes. Of note, REV-ERBa/b deficiency does not compromise circadian expression rhythms of PER2, while REV-ERB target genes, Bmal1 and Npas2, are significantly upregulated. This study emphasizes REV-ERBs function to form an essential link between the circadian clock and a wide variety of cellular physiological functions.
Project description:We address the function of HNF6 in the mouse liver metabolism and Rev-erba cistrome We performed Rev-erba ChIP-seq in mouse livers at 5pm of the day and compared between WT and HNF6-depleted livers.