Retinoid-related Orphan Receptor Research Articles

Identification of Target Genes for Retinoid-related Orphan Receptors Involved in the Suppression of Atherosclerosis

Retinoid-related orphan receptor alpha (RORα) participates in regulating several physiological processes, including metabolism and circadian rhythms. RORα is an important regulator of plasma cholesterol levels and is involved in lipid homeostasis. Its activation increases high-density lipoprotein (HDL) levels and metabolism of oxysterols. RORα-deficient mice develop atherosclerosis owing to decreased plasma HDL levels, increased expression of inflammatory cytokines, and ischemia/reperfusion-induced damage. The transcriptional activity of RORα is controlled by cholesterol and its derivatives, endogenous ligands that form transcription initiation complexes. Conversely, when intracellular cholesterol is reduced by lipid-lowering drugs such as statins, which inhibit cholesterol synthesis, the transcriptional activity of RORα is attenuated. Therefore, studies have focused on identifying target genes regulated by RORα involved in alleviating atherosclerosis to develop new therapies. Characterization of ligands, transcription-mediating factors, and transcription initiation complexes involved in the transcriptional regulation of RORα will facilitate the development of synthetic ligands and their potential applications in diseases such as atherosclerosis, dyslipidemia, and diabetes. In this review, we discuss the current literature on the structure and function of RORα, the target genes regulated by RORα, and the potential of RORα as a therapeutic target for atherosclerosis.

Promoter methylation status of RORC, IL17A, and TNFA in peripheral blood leukocytes in adolescents with obesity-related asthma

A higher Th17-immune response characterises obesity and obesity-related asthma phenotype. Nevertheless, obesity-related asthma has a more significant Th17-immune response than obesity alone. Retinoid-related orphan receptor C (RORC) is the essential transcription factor for Th17 polarisation. Previous studies have found that adolescents with obesity-related asthma presented upregulation of RORC, IL17A, and TNFA. However, the mechanisms that cause these higher mRNA expression levels in this asthmatic phenotype are poorly understood. Methylation directly regulates gene expression by adding a methyl group to carbon 5 of dinucleotide CpG cytosine. Thus, we evaluated the relationship between RORC, IL17A, and TNFA methylation status and mRNA expression levels to investigate a possible epigenetic regulation. A total of 102 adolescents (11–18 years) were studied in the following four groups: 1) healthy participants (HP), 2) allergic asthmatic participants (AAP), 3) obese participants without asthma (OP), and 4) non-allergic obesity-related asthma participants (OAP). Real-time qPCR assessed the methylation status and gene expression levels in peripheral blood leukocytes. Remarkably, the OAP and AAP groups have lower promoter methylation patterns of RORC, IL17A, and TNFA than the HP group. Notably, the OAP group presents lower RORC promoter methylation status than the OP group. Interestingly, RORC promoter methylation status was moderately negatively associated with gene expression of RORC (rs = −0.39, p < 0.001) and IL17A (rs = −0.37, p < 0.01), respectively. Similarly, the promoter methylation pattern of IL17A was moderately negatively correlated with IL17A gene expression (rs = −0.3, p < 0.01). There is also a moderate inverse relationship between TNFA promoter methylation status and TNFA gene expression (rs = −0.3, p < 0.01). The present study suggests an association between lower RORC, IL17A, and TNFA gene promoter methylation status with obesity-related asthma and allergic asthma. RORC, IL17A, and TNFA gene promoter methylation patterns are moderately inversely correlated with their respective mRNA expression levels. Therefore, DNA methylation may regulate RORC, IL17A, and TNF gene expression in both asthmatic phenotypes.

Effect of baotaiyin on IL-23 /Th17 immune inflammatory axis in mouse model of spontaneous abortion.

The mechanism for traditional Chinese medicine in treating of recurrent spontaneous abortion is not clear. This study aims to explore the mechanism of baotaiyin in the treatment of recurrent abortion by regulating the immune inflammatory axis of interleukin (IL)-23/helper T cell (Th)17. Spontaneous abortion model mice were randomly divided into a model group, 3 dose (low, medium, and high) groups of baotaiyin, with 10 mice in each group. After 14 days of medication, the levels of IL-17, IL-23, IL-10, and TGF-β in serum were detected with enzyme-linked immunosorbent assay. The proportion of Th17 and regulatory T cells (Treg) cells in spleen lymphocytes was tested with flow cytometry. The expressions of (retinoid-related orphan receptor γt, ROR-γt) and forkhead box P3 (FOXP3) mRNA in decidua tissues was detected with RT-PCR. Embryo absorption rate was counted. Compared with the model group, the absorption rate of embryo and Th17/Treg cell ratio in baotaiyin medium- and high-dose groups were decreased significantly (all P<0.05); the levels of IL-17 and IL-23 in serum were decreased (both P<0.05), while the levels of TGF-β and IL-10 in baotaiyin medium- and high-dose groups were increased (P<0.05, P<0.01, respectively); the expression of ROR-γt mRNA was decreased and the expression of FOXP3 mRNA was increased (all P<0.01) in decidua tissues of baotaiyin medium- and high-dose groups. Baotaiyin inhibits the positive feedback cycle of IL-23/Th17 immune inflammatory axis, which regulates Th17/Treg cell balance, mediates the maternal and fetal immune tolerance, and prevents the recurrent abortion.

Natural Compound 2,2′,4′-Trihydroxychalcone Suppresses T Helper 17 Cell Differentiation and Disease Progression by Inhibiting Retinoid-Related Orphan Receptor Gamma T

Retinoid-related orphan receptor γt (RORγt), a vital transcription factor for the differentiation of the pro-inflammatory Th17 cells, is essential to the inflammatory response and pathological process mediated by Th17 cells. Pharmacological inhibition of the nuclear receptor RORγt provides novel immunomodulators for treating Th17-driven autoimmune diseases and organ transplant rejection. Here, we identified 2,2',4'-trihydroxychalcone (TDC), a natural chalcone derivant, binds directly to the ligand binding domain (LBD) of RORγt and inhibited its transcriptional activation activity. Using three mice models of Th17-related diseases, it was found that the administration of TDC effectively alleviated the disease development of experimental autoimmune encephalomyelitis (EAE), experimental colitis, and skin allograft rejection. Collectively, these results demonstrated TDC targeting RORγt to suppress Th17 cell polarization, as well as its activity, thus, indicating the potential of this compound in treating of Th17-related autoimmune disorders and organ transplant rejection disorders.

Impact of interleukin-32α on T helper cell-related cytokines, transcription factors, and proliferation in patients with type 2 diabetes mellitus

Objective The ability of interleukin (IL)-32α to induce T helper (Th) 1, Th17, and Treg cytokines (interferon gamma [IFN-γ], IL-17, and IL-10, respectively), and transcription factors ([signal transducer and activator of transcription (STAT) 1 and T-box (T-bet) for Th1, STAT3 and retinoid-related orphan receptor (ROR)-γt for Th17, and STAT5 and forkhead box P3 (Foxp3) for Treg]) were investigated in type 2 diabetes mellitus (T2DM). IL-32α effects on Th cell proliferation and related factors including IL-2 and NF-κB were also explored. Methods Serum levels of IL-32α in 31 patients and 31 healthy controls (HCs) were determined by ELISA assay. CD4+ T cells cultured with polyclonal activators in the presence and absence of recombinant IL-32α (rIL-32α). Gene expressions in cultured Th cells were assessed with real-time PCR. Cytokines in supernatants were measured with ELISA. Proliferation experiments were assessed by flow cytometry. Results The patients showed significant increase in IL-32α levels compared with HCs and its levels were positively correlated with fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c). rIL-32α enhanced IL-17 and IL-2 production, increased ROR-γt and NF-κB expression, and enhanced Th proliferation in both patients and HCs. In patients, IL-17, ROR-γt, NF-κB, and proliferation levels were higher than those in HCs, in cultures with and without rIL-32α (rIL-32α+ and rIL-32α-). IL-2 levels in rIL-32α+cultures of patients were significantly higher than the HCs, and it was positively correlated with proliferation rate and NF-κB expression. Conclusions Aberrant IL-32α levels are participated in T2DM pathogenesis. IL-32α potently induces Th17-related factors and amplifies the proliferative function of T cells. Highlights Enhanced serum levels of IL-32α in T2DM patients was correlated with FPG and HbA1c. IL-32α increases ROR-γt expression and IL-17 production, and induces Th17 cells. IL-32α enhances NF-κB expression and IL-2 production, and promotes Th proliferation. IL-32α is more effective for inducing Th17 cells and proliferation in the patients. IL-32α axis could be mentioned as a future therapeutic goal for the T2DM.

Hepatic Niemann-Pick C1-Like 1 exacerbates non-alcoholic fatty liver disease by re-absorbing specific biliary oxysterols

BackgroundDietary oxysterols are believed to be associated with the progression of non-alcoholic fatty liver disease (NAFLD). However, the molecular basis of the association between dietary oxysterols and NAFLD is poorly understood. We hypothesized that hepatic Niemann-Pick C1-Like 1 (NPC1L1), a cholesterol re-absorber from bile to the liver, would regulate hepatic oxysterol levels and affects NAFLD progression. Methods and resultsConsidering the species differences in hepatic NPC1L1 expression, we used liver-specific NPC1L1 transgenic (NPC1L1Tg) mice as a human model and demonstrated that oxysterol-rich heated cholesterol exacerbated high-fat diet-induced steatosis, an early stage of NAFLD, in a hepatic NPC1L1-dependent manner. Analyses of hepatic and biliary oxysterol levels in NPC1L1Tg mice and in vitro oxysterol uptake assays with NPC1L1-overexpressing cells revealed that NPC1L1 can uptake some, but not all, oxysterols and suppress their biliary excretion. Furthermore, in vitro and in vivo analyses revealed that 22(R)-hydroxycholesterol (22R-OHC) and 25-hydroxycholesterol (25-OHC), which are NPC1L1 substrates, were primarily involved in steatosis progression, via the activation of liver X receptor α and retinoid-related orphan receptor γ, respectively. Consistent with these results, examination of clinical specimens revealed that among the 14 major oxysterols analyzed, plasma concentrations of 22R-OHC and 25-OHC were significantly positively correlated with hepatic fat accumulation in humans. ConclusionsAmong the major dietary oxysterols, 22R-OHC and 25-OHC are particularly potent in promoting the progression of hepatic steatosis in a hepatic NPC1L1-dependent manner.

Diallyl disulfide inhibits proliferation, epithelial—mesenchymal transition, and invasion through RORα-mediated downregulation of Wnt1/β-catenin pathway in gastric cancer cells

Overactivation of Wnt/β-catenin pathway due to dysfunction of retinoid-related orphan receptor α (RORα) is related to cancer development and progression. Diallyl disulfide (DADS), an active component of garlic, has been reported in our previous study for upregulation of RORα expression in gastric cancer (GC) cells. It remains to be elucidated the role and mechanism of RORα in DADS against GC. This study revealed that DADS treatment resulted in reduced expression levels of Wnt1, β-catenin, TCF-4, intranuclear β-catenin and p-β-catenin in GC cells, concomitant with the compromised expression of β-catenin target genes (Axin, c-Jun, and c-Myc). RORα overexpression augmented DADS-induced downregulation of Wnt1/β-catenin pathway, G2/M phase arrest, and cell growth inhibition in vitro and in vivo. Contrarily, knockdown of RORα attenuated these effects of DADS. Interestingly, DADS induced an increase in the binding of RORα to β-catenin, which may lead to reduction of β-catenin phosphorylation and nuclear translocation. This interplay modulated by DADS may affect β-catenin target gene expression for that the opposite results were observed in DADS-treated RORα knockdown and overexpression cells. DADS caused a decrease in vimentin, snail and MMP-9, as well as an increase in E-cadherin and TIMP3 expression, which restricted epithelial‑mesenchymal transition (EMT), migration, and invasion. The aforementioned effects of DADS were weakened simultaneously when the suppression of DADS on the Wnt1/β-catenin pathway was resisted by knockdown of RORα. In contrast, overexpression of RORα enhanced the effects of DADS. Therefore, RORα-mediated downregulation of Wnt1/β-catenin pathway could undertake an important role in anticancer activity of DADS against GC cell proliferation, EMT, migration, and invasion.

Abstract P345: Inhibition Of Nuclear Receptor Retinoid-related Orphan Receptor γt Attenuates Interleukin-17A Production And Ameliorates Angiotensin II-induced Neuroinflammation And Hypertension In Rats

Interleukin (IL)-17A, a key inflammatory mediator produced primarily by T helper (Th) 17 cells, has been implicated in the pathogenesis of cardiovascular diseases including hypertension and heart failure. IL-17A can access the brain by disrupting blood-brain barrier (BBB) integrity to induce neuroinflammation. We previously reported that IL-17A contributes to angiotensin (ANG) II-induced hypertension via promoting neuroinflammation and sympathetic excitation. The nuclear receptor retinoid-related orphan receptor γt (RORγt) is a master transcription factor regulating Th17 cell differentiation. Here, we sought to determine whether systemic inhibition of RORγt attenuates IL-17A production and diminishes ANG II-induced neuroinflammation and hypertension. Sprague-Dawley rats received a 2-week subcutaneous (sc) infusion of ANG II (150 ng/kg/min) combined with daily sc injection of a RORγt inhibitor digoxin or vehicle (VEH). Compared with the control animals, blood pressure (162±5* vs 118±3 mmHg, *P&lt;0.05) and sympathetic tone as indicated by blood pressure change in response to ganglionic blockade (55±5* vs 23±3 mmHg) were increased in ANG II+VEH rats, which were reduced (38-41%*) in ANG II+digoxin rats. ANG II+VEH rats also had elevated RORγt mRNA in peripheral blood mononuclear cells (PBMCs: 3.38±0.70* vs 1.12±0.22) and higher IL-17A levels in plasma (23.22±5.85 * vs 4.30±0.66 pg/mL), along with increased IL-17A levels in cerebrospinal fluid (CSF: 11.89±1.91* vs 2.01±0.55 pg/mL), mRNA of IL-17A (3.02±0.48* vs 1.07±0.17), cytokines tumor necrosis factor (TNF)-α (2.78±0.45* vs 1.04±0.12) and IL-1β (2.57±0.53* vs 1.03±0.14) in the hypothalamic paraventricular nucleus (PVN), a key cardiovascular-related center in the brain. Although RORγt mRNA was unchanged in PBMCs, levels of IL-17A in plasma and CSF, mRNA of IL-17A, TNF-α and IL-1β in the PVN was reduced (41-62 %*) in ANG II+digoxin rats. Additionally, mRNA of caveolin-1 (2.26±0.39* vs 1.06±0.17), a marker of the BBB permeability, was increased in the PVN in ANG II+VEH rats and decreased (43%*) in ANG II+digoxin rats. These data suggest that RORγt inhibition improves ANG II-induced hypertension and sympathetic activation probably by reducing IL-17A production and neuroinflammation.

RORA rs8042149 polymorphism moderates the association between PTSD symptom severity and transverse temporal gyrus thickness in Han Chinese adults who lost their only child

BackgroundThe G allele in retinoid-related orphan receptor alpha (RORA, rs8042149) gene is associated with post-traumatic stress disorder (PTSD) diagnosis and more severe symptoms, reported in the first genome-wide association study of PTSD and subsequent replication studies. Although recent MRI studies identified brain structural deficits in RORA rs8042149 risk G allele carriers, the neural mechanism underlying RORA–related brain structural changes in PTSD remains poorly understood. MethodsThis study included 227 Han Chinese adults who lost their only child. Cortical thickness and subcortical volume were extracted using FreeSurfer, and PTSD severity was assessed using the Clinician-Administered PTSD Scale. Hierarchical linear regression was used to assess the interaction effect between RORA genotypes (T/T, G/T, and G/G) and PTSD severity on cortical and subcortical structures. ResultsSignificant genotype × PTSD symptom severity interaction effects were found for bilateral transverse temporal gyrus thickness. For individuals with the homozygous T/T genotype, current PTSD symptom severity was positively associated with bilateral transverse temporal gyrus thickness. For individuals with heterozygous G/T genotype, current PTSD symptom severity was negatively associated with the left transverse temporal gyrus thickness. No significant main or interaction effects were found in any subcortical regions. LimitationCross-sectional design of this study. ConclusionThese findings suggest that the non-risk T/T genotype – but not the risk G allele carriers – has a potentially protective or compensatory role on temporal gyrus thickness in adults who lost their only child. These results highlight the moderation effect of RORA polymorphism on the relationship between PTSD symptom severity and cortical structural changes.

High density lipoprotein inhibited group II innate lymphoid cells proliferation and function in allergic rhinitis

BackgroundMore and more studies had suggested that dyslipidemia was closely related to allergic diseases. High density lipoprotein (HDL) often plays anti-inflammatory and anti-oxidative roles by suppressing immune cell chemotaxis and activation. We aimed to explore the role of HDL in the regulation of group II innate lymphoid cells (ILC2) in allergic rhinitis (AR).MethodsThe blood lipid levels and their correlation with symptom scores of 20 AR subjects and 20 controls were analyzed. Purified ILC2 were stimulated by HDL and cytokines production were examined by enzyme-linked immunosorbent assay (ELISA) and flow cytometry. The mRNA levels of GATA binding protein 3(GATA3) and retinoid-related orphan receptor α (RORα) expressed by ILC2 were detected using reverse transcription polymerase chain reaction (RT-PCR).ResultsHDL level was significantly lower in AR than controls and correlated with the symptom scores. The serum HDL levels were negatively related to the increased number of ILC2, IL-5+ ILC2, and IL-13+ ILC2 in AR patients. HDL decreased the number of ILC2 and type II cytokines levels significantly by inhibiting expression of GATA3 and RORα.ConclusionsOur data provide preliminary evidence that HDL may play a negative role in ILC2 inflammation in AR, suggesting that HDL may serve as promising treatment target in AR.

Interleukin 35 regulates interleukin 17 expression and T helper 17 in patients with proliferative diabetic retinopathy

ABSTRACT T helper 17 (Th17) cells regulate inflammatory processes and are implicated in pathogenesis of proliferative diabetic retinopathy (PDR) through modulation of interleukin-17 (IL-17). IL-35, anti-inflammatory factor, negatively mediates IL-17 expression and Th17 differentiation. In this study, the role of IL-35 in PDR was assessed. The results showed that IL-35 was down-regulated, while IL-17 was up-regulated, in peripheral blood mononuclear cells (PBMCs) of PDR patients. In addition, immunofluorescence analysis indicated that frequency of Th17 cells was enhanced in the PBMCs of PDR patients. However, incubation with IL-35 reduced the Th17 cell frequency and decreased the level of IL-17 in CD4+ T lymphocytes. Moreover, the levels of transcription factors essential for Th17 differentiation, ROR α (retinoid-related orphan receptor alpha) and ROR γt, were reduced by IL-35 treatment. In conclusion, IL-35 reduced level of IL-17 and inhibited Th17 differentiation to protect against PDR.

POU6F1 cooperates with RORA to suppress the proliferation of lung adenocarcinoma by downregulating HIF1A signaling pathway

Lung adenocarcinoma (LUAD) represents the most frequently diagnosed histological subtype of non-small cell lung cancer with the highest mortality worldwide. Transcriptional dysregulation is a hallmark of nearly all kinds of cancers. In the study, we identified that the POU domain, class 6, transcription factor 1 (POU6F1), a member of the POU family of transcription factors, was closely associated with tumor stage and death in LUAD. We revealed that POU6F1 was downregulated in LUAD tissues and downregulated POU6F1 was predictive of an unfavorable prognosis in LUAD patients. In vitro assays, including CCK8, soft agar, transwell, clone formation, wound-healing assay, and nude mouse xenograft model all revealed that POU6F1 inhibited the growth and invasion of LUAD cells. Mechanistically, POU6F1 bound and stabilized retinoid-related orphan receptor alpha (RORA) to exert the transcriptional inhibition of hypoxia-inducible factor 1-alpha (HIF1A) and alter the expression of HIF1A signaling pathway-associated genes, including ENO1, PDK1, and PRKCB, thereby leading to the suppression of LUAD cells. Collectively, these results demonstrated the suppressive role of POU6F1/RORA in the progression of LUAD and may potentially be used as a target for the treatment of LUAD.

Effect of tetra-hydroxylated bile acid on size and insulin sensitivity of subcutaneous adipocytes in healthy lean cats

Obesity leads to insulin resistance and is a major risk factor for the development of diabetes mellitus in cats. Prevention of obesity and obesity-induced insulin resistance is difficult, and reliable long-term strategies are currently lacking. Retinoid-related orphan receptor gamma (RORγ) was recently identified as an important transcription factor in the development of large insulin-resistant adipocytes in mice and humans. RORγ negatively affects adipocyte differentiation through expression of its target gene matrix metalloproteinase 3 (MMP3) and promotes the development of large insulin-resistant adipocytes. Preliminary studies in mice showed that RORγ can be inhibited by its ligand tetra-hydroxylated bile acid (THBA). In the present study, serum THBA levels were determined in healthy and diabetic cats. Moreover, potential side effects and the effects of THBA supplementation on adipocyte size, mRNA expression of RORγ, MMP3, interleukin 6, tumor necrosis factor α, adiponectin and leptin in feline subcutaneous adipocytes and insulin sensitivity were investigated in healthy normal weight cats. Thirteen healthy and 13 diabetic cats were used for determination of serum THBA level, and six healthy normal-weight cats were included in a feeding trial. Similar THBA levels were determined in serum of healthy and diabetic cats. Supplementation of 5 mg/kg THBA for 8 wk did not cause any negative effect on feeding behavior, general condition and blood parameters of tested cats. It significantly reduced adipocyte size and mRNA expression of MMP3, interleukin 6, and tumor necrosis factor α in adipocytes, while mRNA expression of adiponectin significantly increased and mRNA expression of RORγ and leptin remained unchanged. Administration of THBA did not influence fasting blood glucose levels or the response of cats to acute insulin administration. Based on these results, THBA is palatable and is considered safe for use in cats. It reduces expression of MMP3 and promotes the development of small adipocytes with increased expression of adiponectin and reduced expression of interleukin 6 and tumor necrosis factor α. Further studies are recommended to evaluate the effect of THBA on adipocyte size and insulin sensitivity in obese cats.

WSDTNBI: a novel network-based inference method for virtual screening.

In recent years, the rapid development of network-based methods for the prediction of drug–target interactions (DTIs) provides an opportunity for the emergence of a new type of virtual screening (VS), namely, network-based VS. Herein, we reported a novel network-based inference method named wSDTNBI. Compared with previous network-based methods that use unweighted DTI networks, wSDTNBI uses weighted DTI networks whose edge weights are correlated with binding affinities. A two-pronged approach based on weighted DTI and drug–substructure association networks was employed to calculate prediction scores. To show the practical value of wSDTNBI, we performed network-based VS on retinoid-related orphan receptor γt (RORγt), and purchased 72 compounds for experimental validation. Seven of the purchased compounds were confirmed to be novel RORγt inverse agonists by in vitro experiments, including ursonic acid and oleanonic acid with IC50 values of 10 nM and 0.28 μM, respectively. Moreover, the direct contact between ursonic acid and RORγt was confirmed using the X-ray crystal structure, and in vivo experiments demonstrated that ursonic acid and oleanonic acid have therapeutic effects on multiple sclerosis. These results indicate that wSDTNBI might be a powerful tool for network-based VS in drug discovery.

LncRNA HOTTIP from synovial fibroblast-derived exosomes: A novel molecular target for rheumatoid arthritis through the miR-1908–5p/STAT3 axis

Rheumatoid arthritis (RA) is a chronic inflammation mediated by autoimmune responses. HOTTIP, a long noncoding RNA (lncRNA), participates in cell proliferation and invasion. However, the correlation between HOTTIP and RA remains unclear. Therefore, this study aimed to clarify how HOTTIP works in RA and to investigate its role in the development of RA. Flow cytometry was used to analyze cell cycle progression. Binding between HOTTIP, signal transducer and activator of transcription 3 (STAT3) and miR-1908–5p was demonstrated by dual-luciferase assays. Quantitative real-time polymerase chain reaction (qRT–PCR) was used to measure the expression of T cell differentiation-related proteins. We found that HOTTIP was upregulated in rheumatoid arthritis synovial fibroblasts (RASFs). HOTTIP directly bound to miR-1908–5p and negatively modulated miR-1908–5p expression while positively regulating STAT3. The effects of HOTTIP overexpression on regulating the balance of the Th17/Treg cell ratio were partly reversed by miR-1908–5p overexpression. In addition, in vivo experiments demonstrated that overexpression of HOTTIP aggravated inflammation in RA mice, which was demonstrated by hematoxylin and eosin (HE) staining and the increased expression levels of CD4+ interleukin (IL)-17+, forkhead Box P3 (FOXP3) and retinoid-related orphan receptor gamma-t (RORγt). In summary, our study suggests that HOTTIP plays a damaging role in RA by promoting inflammation, which may be related to the regulation of miR-1908–5p expression and the STAT3 signaling pathway. These results suggest that the regulation of HOTTIP may be a promising therapeutic strategy for RA.

Melatonin attenuates low shear stress-induced pyroptosis and endothelial cell dysfunction via the RORα/miR-223/STAT-3 signalling pathway.

Endothelial cells sense changes in blood flow shear stress and affect the progression of atherosclerotic plaques. Pyroptosis is an inflammatory form of cell death and has been implicated in cardiovascular diseases. Melatonin and its nuclear receptor retinoid-related orphan receptor α (RORα) have protective effects on the development of atherosclerosis. To date, whether melatonin can prevent endothelial cell pyroptosis and dysfunction in pathological shear stress remains unclear. In the present study, human umbilical vein endothelial cells (ECs) were cultured under low shear stress conditions (5 dyne/cm2) for 24 h and treated with or without melatonin (2 µmol/l). The binding sites of the microRNA (miR)-223 promoter and RORα were predicted using the JASPAR website. Expression of pyroptosis-related proteins, including cleaved N-terminal gasdermin D, caspase-1, intercellular adhesion molecule 1 (ICAM-1) and nitric oxide (NO) were assessed. The results indicated that low shear stress increased pyroptosis and ICAM-1 expression, whereas it decreased NO levels. Melatonin alleviated pyroptosis and ICAM-1 expression and increased the production of NO in ECs. Further assessment revealed that low-level shear stress decreased RORα protein and mRNA expression, whereas melatonin would bind to RORα and thereby promoted miR-223 transcription in ECs. The present study also identified signal transducer and activator of transcription 3 (STAT-3) as a potential target gene of miR-223-3p. When transfected with miR-223 inhibitor, ECs up-regulated the expression of pyroptosis-related proteins and ICAM-1, and down-regulated NO levels. By contrast, silencing STAT-3 expression diminished the protective effect of miR-223. These results indicated that melatonin prevented ECs from undergoing pyroptosis and alleviated dysfunction via the RORα/miR-223/STAT-3 signalling pathway. This information could aid in the development of novel therapeutic approaches and provide new insights into atherosclerosis.

Inverse Agonist of Retinoid-Related Orphan Receptor-Alpha Prevents Apoptosis and Degeneration in Nucleus Pulposus Cells via Upregulation of YAP.

Intervertebral disc degenerative disease (IDD) is the most common degenerative spine disease, which leads to chronic low back pain and symptoms in the lower extremities. In this study, we found that RORα, a member of the retinoid-related orphan receptor family, is significantly elevated in nucleus pulposus tissue in IDD patients. The elevation of RORα is associated with increased apoptosis of nucleus pulposus (NP) cells. Therefore, we applicated a well-established inverse agonist of RORα, SR3335, to investigate its role in regulating NP cell metabolism and apoptosis. To further investigate the mechanism that SR3335 regulates the pathogenesis of IDD in vitro, tumor necrosis factor alpha (TNF-α) stimulation was used in human NP cells to mimic the hostile environment that leads to degeneration. We found that SR3335 treatment reversed the trend of increased apoptosis in NP cells induced by TNF-α treatment. Next, TNF-α treatment upregulated the expression of type II collagen and aggrecan and downregulated MMP13 (matrix-degrading enzyme matrix metalloproteinase 13) and ADAMTS4 (a disintegrin and metalloproteinase with thrombospondin motifs 4). However, these effects were reversed after SR3335 treatment. Furthermore, we find that SR3335 mediated the effect in NP cells by regulating the YAP signaling pathway, especially by affecting the phosphorylation state of YAP. In conclusion, the reduction of matrix degradation enzymes and apoptosis upon SR3335 treatment suggests that SR3335 is a promising drug in reversing the deleterious microenvironment in IDD patients.

Pseudomonas aeruginosa outer membrane vesicles ameliorates lung ischemia-reperfusion injury by regulating the balance of regulatory T cells and Th17 cells through Tim-3 and TLR4/NF-κB pathway.

Regulatory T cells (Tregs) and T helper (Th) 17 cells are two subsets of CD4 + T cells with opposite effects which play a crucial role in the pathogenesis of lung injury. In this study, we aim to investigate the protective effect of Pseudomonas aeruginosa outer membrane vesicles (OMVs) preconditioning on lung ischemia-reperfusion (I/R) injury and potential mechanisms. Pathogen-free C57BL/6 mice were randomly divided into four groups: control, Control + OMVs, I/R and I/R + OMVs groups. Bronchoalveolar lavage fluid (BALF), serum, and lung tissues were collected and analyzed for pathophysiology and immune mechanism. OMVs not only attenuated tissue injury and respiratory physiologic function but also mediated the downregulation of lung wet-to-dry weight ratio and the reduction of total protein concentration. The numbers of total cells, macrophages, neutrophils, and lymphocytes were markedly decreased in the I/R mice following OMVs preconditioning. OMVs also decreased inflammatory cytokines associated with CD4 + T cells in both BALF and serum. In addition, the level of Tregs and its transcription factor forkhead box P3 (Foxp3) were significantly increased, while the level of Th17 cells and its transcription factor retinoid-related orphan receptor γ (RORγt) were significantly decreased following OMVs preconditioning. In the process of exploring the underlying protection mechanisms of OMVs, we found that OMVs preconditioning significantly reduced protein expression of Toll-like receptor 4 (TLR4), which in turn not only inactivated myeloid differentiation factor 88 (MyD88) and Phosphorylated nuclear factor kappa B (p-NF-κB), but also simultaneously increased the levels of T-cell immunoglobulin and mucin domain-containing protein 3 (Tim-3). These results suggest that OMVs preconditioning may ameliorate lung I/R injury by regulating the balance of Tregs and Th17 cells through Tim-3 and TLR4/NF-κB pathway.

MicroRNA-766-3p-mediated downregulation of HNF4G inhibits proliferation in colorectal cancer cells through the PI3K/AKT pathway.

Nuclear receptors (NRs) are a class of transcription factors that play a pivotal role in carcinogenesis, but their function in colorectal cancer (CRC) remains unclear. Here, we investigate the role NRs play in CRC pathogenesis. We found that hepatocyte nuclear factor 4 gamma (HNF4G; NR2A2), hepatocyte nuclear factor 4α (HNF4A; NR2A1), and retinoid-related orphan receptor γ (RORC; NR1F3) were significantly upregulated in CRC tissues analyzed by GEPIA bioinformatics tool. The expression of HNF4G was examined in CRC samples and cell lines by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry. Increased expression of HNF4G was strongly associated with high tumor-node-metastasis stage and poor prognosis. Moreover, overexpression of HNF4G significantly promoted the proliferation of CRC cells in vitro. Next, we found that HNF4G promoted CRC proliferation via the PI3K/AKT pathway through targeting of GNG12 and PTK2. In addition, HNF4G was verified as a direct target of microRNA-766-3p (miR-766-3p). miR-766-3p inhibited the proliferation of CRC cells by targeting HNF4G in vitro and in vivo. Collectively, our study indicates that miR-766-3p reduces the proliferation of CRC cells by targeting HNF4G expression and thus inhibits the PI3K/AKT pathway. Therefore, development of therapies which target the miR-766-3p/HNF4G axis may aid in the treatment of CRC.

Preclinical and clinical characterization of the ROR\u03b3t inhibitor JNJ-61803534

The nuclear receptor retinoid-related orphan receptor gamma t (RORγt) plays a critical role in driving Th17 cell differentiation and expansion, as well as IL-17 production in innate and adaptive immune cells. The IL-23/IL-17 axis is implicated in several autoimmune and inflammatory diseases, and biologics targeting IL-23 and IL-17 have shown significant clinical efficacy in treating psoriasis and psoriatic arthritis. JNJ-61803534 is a potent RORγt inverse agonist, selectively inhibiting RORγt-driven transcription versus closely-related family members, RORα and RORβ. JNJ-61803534 inhibited IL-17A production in human CD4+ T cells under Th17 differentiation conditions, but did not inhibit IFNγ production under Th1 differentiation conditions, and had no impact on in vitro differentiation of regulatory T cells (Treg), nor on the suppressive activity of natural Tregs. In the mouse collagen-induced arthritis model, JNJ-61803534 dose-dependently attenuated inflammation, achieving ~ 90% maximum inhibition of clinical score. JNJ-61803534 significantly inhibited disease score in the imiquimod-induced mouse skin inflammation model, and dose-dependently inhibited the expression of RORγt-regulated genes, including IL-17A, IL-17F, IL-22 and IL-23R. Preclinical 1-month toxicity studies in rats and dogs identified doses that were well tolerated supporting progression into first-in-human studies. An oral formulation of JNJ-61803534 was studied in a phase 1 randomized double-blind study in healthy human volunteers to assess safety, pharmacokinetics, and pharmacodynamics. The compound was well tolerated in single ascending doses (SAD) up to 200 mg, and exhibited dose-dependent increases in exposure upon oral dosing, with a plasma half-life of 164 to 170 h. In addition, dose-dependent inhibition of ex vivo stimulated IL-17A production in whole blood was observed, demonstrating in vivo target engagement. In conclusion, JNJ-61803534 is a potent and selective RORγt inhibitor that exhibited acceptable preclinical safety and efficacy, as well as an acceptable safety profile in a healthy volunteer SAD study, with clear evidence of a pharmacodynamic effect in humans.