Retinoid-related Orphan Receptor Research Articles

Functional and phenotypic heterogeneity of group 3 innate lymphoid cells.

SummaryGroup 3 innate lymphoid cells (ILC3), defined by expression of the transcription factor retinoid‐related orphan receptor γt, play key roles in the regulation of inflammation and immunity in the gastrointestinal tract and associated lymphoid tissues. ILC3 consist largely of two major subsets, NCR + ILC3 and LTi‐like ILC3, but also demonstrate significant plasticity and heterogeneity. Recent advances have begun to dissect the relationship between ILC3 subsets and to define distinct functional states within the intestinal tissue microenvironment. In this review we discuss the ever‐expanding roles of ILC3 in the context of intestinal homeostasis, infection and inflammation – with a focus on comparing and contrasting the relative contributions of ILC3 subsets.

Atopic Dermatitis Deteriorates Dextran Sodium Sulfate-Induced Ulcerative Colitis via Thymic Stromal Lymphopoietin in Mice

It has been reported that atopic dermatitis (AD) and ulcerative colitis are related. However, the mechanism underlying this association has not been clarified. We therefore explored how AD induces ulcerative colitis. We developed an AD mouse model (NC/Nga mice) with ulcerative colitis by administering dextran sodium sulfate (DSS) for five days. DSS-induced ulcerative colitis was deteriorated in our conventional AD mouse model compared with specific-pathogen-free (SPF) mice. The plasma levels of thymic stromal lymphopoietin (TSLP) and tumor necrosis factor-α increased the most in DSS-treated conventional mice. Furthermore, the expression of dendritic cells (DC), retinoid-related orphan receptor (ROR)γt (marker of T helper 17 cells [Th17]), interleukin (IL)-17, GATA binding protein 3 (GATA3) (marker of Th2), and IL-4 increased the most in the colon of the DSS-treated conventional mice compared with DSS-treated SPF mice. In addition, TSLP inhibitor (TSLP neutralizing antibody) did not exacerbate ulcerative colitis in DSS-treated conventional mice. These results indicate that TSLP/DC/Th2 and Th17 play major roles in the exacerbation of ulcerative colitis by AD.

Upregulation of SOCS3 in lung CD4+ T cells in a mouse model of chronic PA lung infection and suppression of Th17‑mediated neutrophil recruitment in exogenous SOCS3 transfer in vitro.

Neutrophilic airway inflammation in chronic lung infections caused by Pseudomonas aeruginosa (PA) is associated with T helper (Th)17 responses. Suppressor of cytokine signaling 3 (SOCS3) is the major negative modulator of Th17 function through the suppression of signal transducer and activator of transcription (STAT)3 activation. The aim of the present study was to investigate the expression of SOCS3 in lung CD4+ T cells in a mouse model of chronic PA lung infection and the effect of exogenous SOCS3 on Th17-mediated neutrophil recruitment in vitro. A mouse model of chronic PA lung infection was established and the activation of STAT3 and Th17 response in lung tissues and lung CD4+ T cells was assessed. The protein and mRNA expression of SOCS3 in lung CD4+ T cells was analyzed by western blotting and reverse transcription-quantitative polymerase chain reaction. The authors constructed a recombinant lentivirus carrying the SOCS3 gene and transferred it into lung CD4+ T cells isolated from a mouse model. These transfected cells were stimulated with interleukin (IL)-23 in vitro and the protein level of p-STAT3 and retinoid-related orphan receptor (ROR)γt was determined by western blotting. The expression of IL-17A+ cells was analyzed by flow cytometry and the level of IL-17A in cell culture supernatant was measured by ELISA. The mouse lung epithelial cell line, MLE-12, was cocultured with lung CD4+ T cells that overexpressed the SOCS3 gene and the culture supernatant was harvested and used for a chemotaxis assay. Compared with control mice, mice with chronic PA lung infection had significantly higher level of p-STAT3 and Th17 response in both lung tissues and lung CD4+ T cells. The protein and mRNA level of SOCS3 in lung CD4+ T cells increased as the chronic PA lung infection developed. Exogenous SOCS3 gene transfer in PA-infected lung CD4+ T cells decreased p-STAT3 and RORγt expression and suppressed the level of IL-17A+ cells in vitro. MLE-12 cells cocultured with SOCS3-overexpressing lung CD4+ T cells expressed a significantly lower level of neutrophil chemoattractants chemokine (C-X-C motif) ligand (CXCL) 1 and CXCL5, and recruited significantly smaller numbers of migrating neutrophils than those cocultured with control cells. SOCS3 was upregulated in lung CD4+ T cells following the activation of STAT3/Th17 axis in a mouse model of chronic PA lung infection. Exogenous SOCS3 transfer in PA-infected lung CD4+ T cells suppresses Th17-mediated neutrophil recruitment in vitro.

Nuclear receptor retinoid-related orphan receptor alpha promotes apoptosis but is reduced in human gastric cancer.

Retinoid-related orphan receptor α (RORα) is a nuclear receptor, which regulates inflammation and immune responses, lipid metabolism and circadian rhythm. Although RORα suppresses breast tumor invasion, it is unknown whether RORα is dysregulated in gastric cancer leading to cellular survival. Therefore, we hypothesize that RORα is dysfunctional in gastric carcinoma and this causes decreased apoptosis in gastric cancer cells. To test this hypothesis, we employed human gastric cancer tissues with different stages to determine RORα expression, as well as in vitro human gastric cancer cells to determine how RORα is reduced during apoptosis. We found that the expression of RORα was reduced in gastric tissues with cancer, and this correlated with increased TNM stages. The mechanisms underlying RORα reduction is due to the reduced activation of AMP-activated protein kinase (AMPK), as a selective AMPK activator AICAR increased RORα activation and level in human gastric cancer cells. Furthermore, AICAR treatment increased RORα recruitment on the promoters of tumor suppressor genes (i.e., FBXM7, SEMA3F and p21) leading to apoptosis in human gastric cancer cells. Taken together, RORα reduction occurs in gastric cancer leading to the survival of tumor cells, which is attenuated by AMPK. Therefore, both RORα and AMPK are potential targets for the intervention and therapy in gastric carcinoma.

Retinoid-Related Orphan Receptor β and Transcriptional Control of Neuronal Differentiation.

The ability to generate neuronal diversity is central to the function of the nervous system. Here we discuss the key neurodevelopmental roles of retinoid-related orphan receptor β (RORβ) encoded by the Rorb (Nr1f2) gene. Recent studies have reported loss of function of the human RORB gene in cases of familial epilepsy and intellectual disability. Principal sites of expression of the Rorb gene in model species include sensory organs, the spinal cord, and brain regions that process sensory and circadian information. Genetic analyses in mice have indicated functions in circadian behavior, vision, and, at the cellular level, the differentiation of specific neuronal cell types. Studies in the retina and sensory areas of the cerebral cortex suggest that this orphan nuclear receptor acts at decisive steps in transcriptional hierarchies that determine neuronal diversity.

The immunomodulatory effects of TNF-α inhibitors on human Th17 cells via RORγt histone acetylation.

The presence of interleukin (IL)-17-related cytokines correlates with rheumatoid arthritis (RA) pathogenesis. Epigenetic modifications, including histone acetylation, regulate gene expression in RA pathogenesis. Tumour necrosis factor-alpha (TNF-α) inhibitors such as etanercept and adalimumab, represent a breakthrough in RA treatment. We aimed to investigate the effects of etanercept and adalimumab on human Th17-polarized cells and the possible intracellular regulators of these effects, including the Th17-specific transcription factors signal transducer, activator of transcription 3 (STAT3), retinoid-related orphan receptor γ-T (RORγt) and epigenetic modification. Human CD4+ T cells from healthy subjects and patients with RA were pretreated with TNF-α inhibitors and then being polarized into IL-17-producing cells. The Th17-related cytokine levels in the culture supernatants were determined with an enzyme-linked immunosorbent assay. Intracellular signalling was investigated by western blot, real-time RT-PCR, and chromatin immunoprecipitation. Th17-polarized cells from patients with RA produced more IL-17A, IL-17F and IL-22 than those from healthy subjects. Etanercept and adalimumab suppressed IL-17A, IL-17F and IL-22 levels in Th17-polarized cells from healthy subjects and patients with RA. Western blot analysis revealed that etanercept and adalimumab decreased mitogen-activated protein kinase-phospho-p38, nuclear factor-κB-phospho-p65, phospho-STAT3 and RORγt levels. Etanercept and adalimumab decreased histone (H)3 and H4 acetylation in the RORγt gene promotor region by decreasing the recruitment of the acetyltransferases p300, CBP and PCAF. The present study broadens our knowledge of the mechanisms underlying the immunomodulatory effects of TNF-α inhibitors in rheumatoid arthritis treatment.

Nuclear receptor retinoid-related orphan receptor α deficiency exacerbates high-fat diet-induced cardiac dysfunction despite improving metabolic abnormality

Retinoid-related orphan receptor α (RORα), a member of the metabolic nuclear receptor superfamily, plays a vital regulatory role in circadian rhythm and metabolism. Here, we investigated the role of RORα in high-fat diet (HFD)-induced cardiac impairments and the underlying mechanisms involved. RORα-deficient stagger mice (sg/sg) and wild type (WT) littermates were fed with either standard diet or HFD. At 20weeks after HFD treatment, RORα deficiency resulted in significantly decreased body weight gain, improved dyslipidemia and ameliorated insulin resistance (evaluated by blood biochemical and glucose/insulin tolerance tests) compared with WT control. However, compared with HFD-treated WT mice, HFD-treated sg/sg mice exhibited significantly augmented myocardial hypertrophy, cardiac fibrosis (wheat germ agglutinin, masson trichrome and sirius red staining) and cardiac dysfunction (echocardiography and hemodynamics). Mechanistically, RORα deficiency impaired mitochondrial biogenesis and function. Additionally, RORα deficiency resulted in inhibition of the AMPK-PGC1α signaling pathway. In contrast, cardiomyocyte-specific RORα overexpression ameliorated myocardial hypertrophy, fibrosis and dysfunction by restoring AMPK-PGC1α signaling, and subsequently normalizing mitochondrial biogenesis. These findings demonstrated for the first time that nuclear receptor RORα deficiency aggravated HFD-induced myocardial dysfunction at least in part by impairing mitochondrial biogenesis in association with disrupting AMPK-PGC1α signaling. This article is part of a Special Issue entitled: Genetic and epigenetic control of heart failure - edited by Jun Ren and Megan Yingmei Zhang.

Support for the association between RORA gene polymorphisms and the DSM-5 posttraumatic stress disorder symptoms in male earthquake survivors in China.

This study examined the association between interaction of retinoid-related orphan receptor alpha (RORA) (rs8042149) genotype x trauma exposure and post-traumatic stress disorder (PTSD) symptoms. A total of 1196 Chinese adults who suffered from a deadly 2008 Wenchuan earthquake participated in this study. PTSD symptoms were measured with the PTSD Checklist for DSM-5 (PCL-5). A custom-by-design 2×48-Plex SNPscan™Kit were used to genotype the RORA rs8042149 SNP. Our results showed that the interaction of rs8042149 genotype x trauma exposure was associated with total PTSD symptoms in males. Moreover, the rs8042149 genotype x trauma exposure interaction was only associated with severity of the negative affect, anhedonia and dysphoric arousal symptoms in males. A moderate sample exposed to a specific event was assessed with a self-reported PTSD measure. This study provides preliminary evidence supporting the functional role of RORA in PTSD, and adds to the knowledge for understanding the genetic underpinnings of PTSD. Moreover, this study carries implications for understanding the comorbidity of PTSD and the sex-specific expression of PTSD's symptoms.

Expression of retinoid-related orphan receptor γt (RORγt) of decidual NK22 cells in women with spontaneous miscarriages with or without chromosomal abnormality

Expression of retinoid-related orphan receptor γt (RORγt) of decidual NK22 cells in women with spontaneous miscarriages with or without chromosomal abnormality

Galectin-3 regulates inflammasome activation in cholestatic liver injury.

Macrophage activation is an important feature of primary biliary cholangitis (PBC) pathogenesis and other cholestatic liver diseases. Galectin-3 (Gal3), a pleiotropic lectin, is produced by monocytic cells and macrophages. However, its role in PBC has not been addressed. We hypothesized that Gal3 is a key to induce NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome in macrophages and in turn to propagate proinflammatory IL-17 signaling. In liver tissues from patients with PBC and dnTGF-βRII mice, a model of autoimmune cholangitis, the expression of Gal3, NLRP3, and the adaptor protein adaptor apoptosis-associated speck-like protein was induced, with the downstream activation of caspase-1 and IL-1β. In wild-type hepatic macrophages, deoxycholic acid induced the association of Gal3 and NLRP3 with direct activation of the inflammasome, resulting in an increase in IL-1β. Downstream retinoid-related orphan receptor C mRNA, IL-17A, and IL-17F were induced. In Gal3-/- macrophages, no inflammasome activation was detected. To confirm the key role of Gal3 in the pathogenesis of cholestatic liver injury, we generated dnTGF-βRII/galectin-3-/- (dn/Gal3-/-) mice, which showed impaired inflammasome activation along with significantly improved inflammation and fibrosis. Taken together, our data point to a novel role of Gal3 as an initiator of inflammatory signaling in autoimmune cholangitis, mediating the activation of NLRP3 inflammasome and inducing IL-17 proinflammatory cascades. These studies provide a rationale to target Gal3 in autoimmune cholangitis and potentially other cholestatic diseases.-Tian, J., Yang, G., Chen, H.-Y., Hsu, D. K., Tomilov, A., Olson, K. A., Dehnad, A., Fish, S. R., Cortopassi, G., Zhao, B., Liu, F.-T., Gershwin, M. E., Török, N. J., Jiang, J. X. Galectin-3 regulates inflammasome activation in cholestatic liver injury.

Retinoid-related orphan receptor γ (RORγ) adult induced knockout mice develop lymphoblastic lymphoma.

RORγ is a nuclear hormone receptor which controls polarization of naive CD4+ T-cells into proinflammatory Th17 cells. Pharmacological antagonism of RORγ has therapeutic potential for autoimmune diseases; however, this mechanism may potentially carry target-related safety risks, as mice deficient in Rorc, the gene encoding RORγ, develop T-cell lymphoma with 50% frequency. Due to the requirement of RORγ during development, the Rorc knockout (KO) animals lack secondary lymphoid organs and have a dysregulation in the generation of CD4+ and CD8+ T cells. We wanted to extend the evaluation of RORγ deficiency to address the question whether lymphomas, similar to those observed in the Rorc KO, would develop in an animal with an otherwise intact adult immune system. Accordingly, we designed a conditional RORγ knockout mouse (Rorc CKO) where the Rorc locus could be deleted in adult animals. Based on these studies we can confirm that these animals also develop lymphoma in a similar time frame as embryonic Rorc knockouts. This study also suggests that in animals where the gene deletion is incomplete, the thymus undergoes a rapid selection process replacing Rorc deficient cells with remnant thymocytes carrying a functional Rorc locus and that subsequently, these animals do not develop lymphoblastic lymphoma.

Expression of retinoid-related orphan receptor (ROR)γt on NK22 cells in the peripheral blood and uterine endometrium of women with unexplained recurrent pregnancy loss and unexplained infertility.

Recently, NK22 cells, a subset of interleukin (IL)-22-producing natural killer (NK) cells, were identified. We have previously reported the higher percentage of NK22 cells in women suffering recurrent pregnancy loss (RPL). Moreover, we have also reported lower expression of NKp46, a kind of natural cytotoxicity receptor (NCR), on NK cells and the changes of NK cell producing cytokines in women who experience RPL. NK22 cells express NCRs, such as NKp44 or NKp46. Retinoid-related orphan receptor γt (RORγt) is known as a regulator of NK22 cells; however, in NK22 cells of peripheral blood (PB) and the uterine endometrium (UE), the relationship between NCRs and RORγt is unclear. We investigate RORγt expression NK22 cells in the PB and UE of women with unexplained infertility (uI) or unexplained RPL (uRPL). Lymphocytes were extracted from PB and UE, derived from women with uI or uRPL. Expression of RORγt and NCRs in NK cells and NK cell-produced cytokines were analyzed by flow cytometry. CD56+ /NKp46+ /RORγt+ cells were positively correlated with CD56+ /IL-22+ cells in both PB and UE. CD56bright /NKp46bright /RORγt+ cells were significantly higher in uRPL than in uI, and endometrial CD56bright /NKp46bright /RORγt+ cells were positively correlated with PB. In UE, CD56bright /RORγt+ cells were negatively correlated with CD56bright /interferon-γ+ and CD56bright /tumor necrosis factor-α+ cells of uRPL. RORγt may be associated with NK22 cells in reproduction. Particularly, higher expression of RORγt may be associated with elevated NK22 cells in uRPL.

Effects of grape seed proanthocyanidin extract on airway inflammation and Treg/Th17 balance in asthmatic mice

Objective To explore effect of grape seed proanthocyanidin extract(GSPE)on airway inflammation and hyperresponsiveness of ovalbumin-induced murine asthma model and the associated regulatory effect on Treg/Th17 imbalance. Methods A total of 40 mice were randomly assigned to four experimental groups: control, asthma model, low dose GSPE(40 mg/kg), and high dose GSPE(80 mg/kg). Acute asthma model was established with OVA; airway responsiveness of mice in each group was measured with a noninvasive pulmonary function instrument; lung inflammation changes were observed by pathological HE staining; Treg/Th17 cytokines levels in bronchoalveolar lavage fluid were evaluated by ELISA; the expressions of forkhead/winged helix transcription factor(Foxp3)mRNA and retinoid-related orphan receptor gammat(RORγt)mRNA in lung tissue of each group were gained by Real-time PCR method. Results GSPE inhibited ovalbumin-induced increases in airway responsiveness(P<0.05). Histological studies demonstrated that GSPE substantially inhibited OVA-induced airway inflammation in lung tissue.GSPE decreased IL-17A levels and increased IL-10 levels in bronchoalveolar lavage fluid(P<0.05). In the asthma model group, RORγt mRNA expression in lung tissue was significantly higher than that in the control group(P<0.05)and Foxp3 mRNA expression was significantly lower than that in the control group(P<0.05). In the GSPE group, RORγt mRNA expression was lower than that in asthma model group(P<0.05), however the Foxp3 mRNA expression was higher than that in asthma model group(P<0.05). Conclusion GSPE could alleviate airway hyperresponsiveness and airway inflammation of in asthmatic mice.It can modify the asthmatic mice Treg/Th17 imbalance by decreasing IL-17A and increasing IL-10 concentration at the level of cytokines; and also by increasing Foxp3 mRNA expression and inhibiting the expression of RORγt mRNA at the transcriptional level, which provide a new way for treatment of bronchial asthma. Key words: Grape seed proanthocyanidin extract; Asthma; Forkhead/winged helix transcription factor; Retinoid-related orphan receptor gammat

Expression of retinoid-related orphan receptor γt (RORγt) on NK22 cell in the peripheral blood and uterine endometrium of women with unexplained recurrent pregnancy loss and unexplained infertility

Interleukin-22 (IL-22) is a cytokine that belongs to the IL-10 family of interleukins. It can be produced by T helper 22 (Th22) cells, T helper 1 (Th1) cells, T helper 17 (Th17) cells, natural killer 22 (NK22) cells, natural killer T (NKT) cells, innate lymphoid cells (ILCs), and γδ T cells. IL-22 acts via binding to a heterodimeric transmembrane receptor complex that consists of IL-22R1 and IL-10R2 and mainly contributes to the tissue repair and host defense. Transcription factors such as retinoid orphan receptor γt (RORγt) and signal transducer and activator of transcription 3 (STAT3), have been reported to play important roles in regulation of IL-22 expression. Recently, it has been demonstrated in several studies that microRNAs (miRNAs) potently regulate expression of interleukins, including production of IL-22. Here, we review current knowledge about regulators of IL-22 expression with a particular emphasis on the role of miRNAs.

Expression of retinoid-related orphan receptor γt (RORγt) on NK22 cell in the peripheral blood and uterine endometrium of women with unexplained recurrent pregnancy loss and unexplained infertility

Expression of retinoid-related orphan receptor γt (RORγt) on NK22 cell in the peripheral blood and uterine endometrium of women with unexplained recurrent pregnancy loss and unexplained infertility

Schisandrin B inhibits Th1/Th17 differentiation and promotes regulatory T cell expansion in mouse lymphocytes

Schisandrin B (Sch-B), the most abundant active ingredient of the fruit of Schisandra chinensis, has been proposed to have antioxidant, anti-tumor and anti-inflammatory effects. The present study was undertaken to investigate the effect of Sch-B on differentiation of T helper cells (Th). Using mouse splenic lymphocytes stimulated with concanavalin A (Con A) in vitro and ex vivo as inflammation models, we found that Sch-B significantly inhibited secretion of Th1 and Th17 related cytokines, such as IFN-γ and IL-17. In addition, we found that Sch-B suppressed the differentiation of naive CD4+ T cells into Th1 and Th17 cells, while promoted their differentiation into the regulatory T cells (Treg) in vitro. We further found that Sch-B suppressed transcription of Th1-related T-box transcription factor, T-bet, and Th17-related transcription factor, retinoid related orphan receptor gamma t (RORγt), while enhanced transcription of Treg-related transcription factor forkhead box protein 3 (Foxp3) in naive CD4+ T cells under Th cell polarization conditions. Furthermore, the effect of Sch-B on the T cell differentiation was abrogated by heme oxygenase-1 (HO-1) inhibitor zinc protoporphyrin. Taken together, we conclude that Sch-B can modulate differentiation of naïve CD4+ T cells into specific lineages of effector cells, which may have potential benefits for treatment of autoimmune diseases.

Retinoid-related orphan receptor gamma t (RORγt) inhibitors from Vitae Pharmaceuticals (WO2015116904) and structure proposal for their Phase I candidate VTP-43742

ABSTRACTRetinoic acid receptor-related orphan nuclear receptor gamma t (RORγt or RORC2) is a key transcription factor for the differentiation of naïve proinflammatory CD4+ T cells and the production of T helper-17 (TH17) cells. Inhibiting RORγt activity is thought to be beneficial in targeting a variety of inflammatory and autoimmune disorders, however current candidates remain to be validated in the clinic. Recently Vitae Pharmaceuticals successfully finished its Phase 1 single ascending dose clinical study with their proprietary RORγt inverse agonist VTP-43742. On the basis of the reported promising results, Vitae Pharmaceuticals could currently be considered as having the leading clinical candidate in the RORγt inverse agonist category. This prompts the interest on the exact chemical structure of their clinical candidate. The first relevant patent application (WO2014179564) from Vitae Pharmaceuticals describes RORγt inverse agonists with a 5,6-dihydro-4H-pyrrolo[3,4-d]thiazole core, while in the second and latest patent application (WO2015116904) this element has changed towards a 6,7-dihydro-5H-pyrrolo[3,4-b]pyridine core. By combining information from Vitae’s patent applications and trustworthy online information, the potential elucidation of the chemical structure of clinical candidate VTP-43742 is described.

RNA expression profiling in depressed patients suggests retinoid-related orphan receptor alpha as a biomarker for antidepressant response

Gene expression profiling may be a tool to identify markers of antidepressant treatment response and new potential drug targets. In a first step, we selected 12 males, age- and severity-matched pairs of remitters and non-responders, and analyzed expression profiles in peripheral blood at admission and after 2 and 5 weeks of treatment using Illumina expression arrays. We identified 127 transcripts significantly associated with treatment response with a minimal P -value of 9.41×10 −4 (false discovery rate-corrected). Analysis of selected transcripts in an independent replication sample of 142 depressed inpatients confirmed that lower expression of retinoid-related orphan receptor alpha (RORa, P =6.23×10 −4 ), germinal center expressed transcript 2 (GCET2, P =2.08×10 −2 ) and chitinase 3-like protein 2 (CHI3L2, P =4.45×10 −2 ) on admission were associated with beneficial treatment response. In addition, leukocyte-specific protein 1 (LSP1) significantly decreased after 5 weeks of treatment in responders ( P =2.91×10 −2 ). Additional genetic, in vivo stress responsitivity data and murine hippocampal gene expression findings corroborate our finding of RORa as a transcriptional marker of antidepressant response. In summary, using a genome-wide transcriptomics approach and subsequent validation studies, we identified several transcripts including the circadian gene transcript RORa that may serve as biomarkers indicating antidepressant treatment response.

Addition of Dexamethasone Alters the Bile Acid Composition by Inducing CYP8B1 in Primary Cultures of Human Hepatocytes

Primary human hepatocytes offer the best human in vitro model for studies on human liver cell metabolism. Investigators use a variety of different media supplements and matrix biocoatings and the type of culture system used may influence the outcome. To optimize in vitro conditions for primary human hepatocytes with regard to bile acid synthesis. Human hepatocytes were isolated and cultured on collagen type I or EHS matrigel in cell media with or without dexamethasone. The glucocorticoid receptor (GR) antagonist RU486 was used to elucidate the involvement of GR. Hepatocytes cultured on EHS matrigel produced more bile acids and expressed higher levels of cholesterol 7α-hydroxylase (CYP7A1) than cells cultured on rat tail collagen. Supplementation with dexamethasone increased the formation of cholic acid (CA) and decreased chenodeoxycholic acid formation. In line with these results, the mRNA expression of sterol 12α-hydroxylase (CYP8B1) increased following dexamethasone treatment. Surprisingly, the mRNA expression of CYP7A1 and CYP27A1 was not increased to the same extent. By using the GR antagonist RU486, we concluded that CYP8B1 induction is mediated via a GR-independent pathway. An altered expression of retinoid-related orphan receptor (ROR) α and ROR α target gene Glucose-6-phosphatase (G6Pase) suggests that ROR α signaling may regulate CYP8B1 expression. Primary human hepatocytes have an increased bile acid synthesis rate when cultured on matrigel as compared to collagen. Exposure to glucocorticoid hormones stimulates the expression of CYP8B1, leading to an increased formation of CA and alteration of the bile acid composition. The effect is most likely mediated through a GR-independent pathway, possibly through ROR α.

B Cell-Activating Transcription Factor Plays a Critical Role in the Pathogenesis of Anti-Major Histocompatibility Complex-Induced Obliterative Airway Disease.

Antibodies (Abs) against major histocompatibility complex (MHC) results in T helper-17 (Th17)-mediated immunity against lung self-antigens (SAgs), K-α1 tubulin and collagen V and obliterative airway disease (OAD). Because B cell-activating transcription factor (BATF) controls Th17 and autoimmunity, we proposed that BATF may play a critical role in OAD. Anti-H2K(b) was administered intrabronchially into Batf (-/-) and C57BL/6 mice. Histopathology of the lungs on days 30 and 45 after Ab administration to Batf (-/-) mice resulted in decreased cellular infiltration, epithelial metaplasia, fibrosis, and obstruction. There was lack of Abs to SAgs, reduction of Sag-specific interleukin (IL)-17 T cells, IL-6, IL-23, IL-17, IL-1β, fibroblast growth factor-6, and CXCL12 and decreased Janus kinase 2, signal transducer and activator of transcription 3 (STAT3), and retinoid-related orphan receptor γT. Further, micro-RNA (miR)-301a, a regulator of Th17, was reduced in Batf (-/-) mice in contrast to upregulation of miR-301a and downregulation of protein inhibitor of activated STAT3 (PIAS3) in anti-MHC-induced OAD animals. We also demonstrate an increase in miR-301a in the bronchoalveolar lavage cells from lung transplant recipients with Abs to human leukocyte antigen. This was accompanied by reduction in PIAS3 mRNA. Therefore, we conclude that BATF plays a critical role in the immune responses to SAgs and pathogenesis of anti-MHC-induced rejection. Targeting BATF should be considered for preventing chronic rejection after human lung transplantation.