The Conserved Non-coding Sequences CNS6 and CNS9 Control Cytokine-Induced Rorc Transcription during T Helper 17 Cell Differentiation.

RORγt is the lineage-specific transcription factor for T helper 17 (Th17) cells whose upregulation in developing Th17 cells is critically regulated by interleukin-6 (IL-6) and TGF-ß, the molecular mechanisms of which remain largely unknown. Here we identified conserved non-coding sequences (CNSs) 6 and 9 at the Rorc gene, essential for its expression during Th17 cell differentiation but not required for RORγt expression in innate lymphocytes and γδ T cells. Mechanistically, the IL-6-signal transducer and activator of transcription 3 (STAT3) axis appeared to be largely dependent on CNS9 and only partially on CNS6 in controlling RORγt expression and epigenetic activation of the Rorc locus. TGF-ß alone was sufficient to induce RORγt expression in a CNS6- but not CNS9-dependent manner through CNS6 binding by SMAD proteins. Our study reveals an important synergistic mechanism downstream of IL-6 and TGF-ß in regulation of RORγt expression and Th17 cell commitment via distinct cis-regulatory elements.

Dietary and Microbial Determinants in Food Allergy.

The steep rise in food allergy (FA) has evoked environmental factors involved in disease pathogenesis, including the gut microbiota, diet, and their metabolites. Early introduction of solid foods synchronizes with the "weaning reaction," a time during which the microbiota imprints durable oral tolerance. Recent work has shown that children with FA manifest an early onset dysbiosis with the loss of Clostridiales species, which promotes the differentiation of ROR-γt+ regulatory T cells to suppress FA. This process can be reversed in pre-clinical mouse models by targeted bacteriotherapy. Here, we review the dominant tolerance mechanisms enforced by the microbiota to suppress FA and discuss therapeutic intervention strategies that act to recapitulate the early life window of opportunity in stemming the FA epidemic.

High Glucose Intake Exacerbates Autoimmunity through Reactive-Oxygen-Species-Mediated TGF-ß Cytokine Activation.

Diet has been suggested to be a potential environmental risk factor for the increasing incidence of autoimmune diseases, yet the underlying mechanisms remain elusive. Here, we show that high glucose intake exacerbated autoimmunity in mouse models of colitis and experimental autoimmune encephalomyelitis (EAE). We elucidated that high amounts of glucose specifically promoted T helper-17 (Th17) cell differentiation by activating transforming growth factor-ß (TGF-ß) from its latent form through upregulation of reactive oxygen species (ROS) in T cells. We further determined that mitochondrial ROS (mtROS) are key for high glucose-induced TGF-ß activation and Th17 cell generation. We have thus revealed a previously unrecognized mechanism underlying the adverse effects of high glucose intake in the pathogenesis of autoimmunity and inflammation.

Pin1 maintains the effector program of pathogenic Th17 cells in autoimmune neuroinflammation.

Th17 cells mediated immune response is the basis of a variety of autoimmune diseases, including multiple sclerosis and its mouse model of immune aspects, experimental autoimmune encephalomyelitis (EAE). The gene network that drives both the development of Th17 and the expression of its effector program is dependent on the transcription factor RORγt. In this report, we showed that Peptidylprolyl Cis/Trans Isomerase, NIMA-Interacting 1 (Pin1) formed a complex with RORγt, and enhanced its transactivation activity, thus sustained the expression of the effector genes as well as RORγt in the EAE-pathogenic Th17 cells. We first found out that PIN1 was highly expressed in the samples from patients of multiple sclerosis, and the expression of Pin1 by the infiltrating lymphocytes in the central nerve system of EAE mice was elevated as well. An array of experiments with transgenic mouse models, cellular and molecular assays was included in the study to elucidate the role of Pin1 in the pathology of EAE. It turned out that Pin1 promoted the activation and maintained the effector program of EAE-pathogenic Th17 cells in the inflammation foci, but had little effect on the priming of Th17 cells in the draining lymph nodes. Mechanistically, Pin1 stabilized the phosphorylation of STAT3 induced by proinflammatory stimuli, and interacted with STAT3 in the nucleus of Th17 cells, which resulted in the increased expression of Rorc. Moreover, Pin1 formed a complex with RORγt, and enhanced the transactivation of RORγt to the +11 kb enhancer of Rorc, which enforced and maintained the expression of both Rorc and the effector program of pathogenic Th17 cells in EAE. Finally, the inhibition of Pin1, by genetic knockdown or by small molecule inhibitor, deceased the population of Th17 cells and the neuroinflammation, and alleviated the symptoms of EAE. These findings suggest that Pin1 is a potential therapeutic target for MS and other autoimmune inflammatory diseases.

Evaluation of the activity of cardiac glycosides on RORγ and RORγT nuclear receptors.

Cardiac glycosides, derived from plants and animals, have been recognized since ancient times. These substances hinder the function of the sodium-potassium pump within eukaryotic cells. Many reports have shown that these compounds influence the activity of nuclear receptors. Thus, we assessed the effects of various cardiac glycosides at nontoxic concentrations on RORγ and RORγT. RORγT is a crucial protein involved in the differentiation of Th17 lymphocytes. Sixteen analyzed cardiac glycosides exhibited varying toxicities in HepG2 cells, all of which demonstrated agonistic effects on RORγ, as confirmed in the RORγ-HepG2 reporter cell line. The overexpression of both the RORγ and RORγT isoforms intensified the effects of these compounds. Additionally, these glycosides induced the expression of G6PC, a gene regulated by RORγ, in HepG2 cells. Subsequently, the effects of two endogenous cardiac glycosides (marinobufagenin and ouabain) and the three most potent glycosides (bufalin, oleandrin, and telecinobufagenin) were evaluated in Th17 primary lymphocytes. All of these compounds increased the expression of the IL17A, IL17F, IFNG, and CXCL10 genes, but they exhibited varying effects on GZMB and CCL20 expression. Molecular docking analysis revealed the robust binding affinity of cardiac glycosides for the ligand binding domain of the RORγ/RORγT receptors. Thus, we demonstrated that at nontoxic concentrations, cardiac glycosides have agonistic effects on RORγ/RORγT nuclear receptors, augmenting their activity. This potential can be harnessed to modulate the phenotype of IL17-expressing cells (e.g., Th17 or Tc17 lymphocytes) in adoptive therapy for combating various types of cancer.

RORγt protein modifications and IL-17-mediated inflammation.

RORγt, the master transcription factor for cytokine interleukin (IL)-17, is expressed explicitly in Th17 cells, γδT cells, and type 3 innate lymphoid cells in mice and humans. Since dysregulated IL-17 expression is strongly linked to several human inflammatory diseases, the RORγt-IL-17 axis has been the focus of intense research. Recently, several studies have shown that RORγt is modified by multiple post-translational mechanisms, including ubiquitination, acetylation, SUMOylation, and phosphorylation. This review discusses how post-translational modifications modulate RORγt function and its turnover to regulate IL-17-driven inflammation. Broad knowledge of these pathways is crucial for a clear understanding of the pathogenic role of RORγt+IL-17+ cells and for the development of putative therapeutic strategies to target IL-17-driven diseases such as multiple sclerosis, psoriasis, rheumatoid arthritis, systemic lupus erythematosus, and inflammatory bowel disease.

Shifting phenotype and differentiation of CD11b+Gr.1+ immature heterogeneous myeloid derived adjuster cells support inflammation and induce regulators of IL17A in imiquimod induced psoriasis.

OBJECTIVE AND DESIGN: The exact immunological mechanism of widespread chronic inflammatory skin disorder psoriasis has not been fully established. CD11b+Gr.1+ myeloid-derived cells are immature heterogeneous cells with T-cell suppressive property in neoplasia; however, influence of these cells on adaptive immunity is highly contextual; therefore, we dubbed these cells as myeloid-derived adjuster cells (MDAC). We studied imiquimod induced psoriasis in mouse model and evaluated for the first time the RORγt-NFAT1 axis in MDACs and the function, differentiation and interaction of these cells with T cells. MATERIALS AND METHODS: The status of T cells and MDACs; their functionality and differentiation properties, and the roles of RORγt and NFAT1 in MDACs were evaluated using flow cytometry, qRT-PCR and confocal imaging. RESULTS: We found gradual increase in T cells and MDACs and an increase in the number of IL17 -secreting MDACs and T cells in the skin of psoriatic animals. We also noted that MDAC differentiation is biased toward M1 macrophages and DCs which perpetuate inflammation. We found that psoriatic MDACs were unable to suppress T-cell proliferation or activation but seemingly helped these T cells produce more IL17. Inhibition of the RORγt/NFAT1 axis in MDACs increased the suppressive nature of MDACs, allowing these cells to suppress the activity of psoriatic T-cells. CONCLUSION: Our results indicate that altered MDAC properties in psoriatic condition sustains pathological inflammation and RORγt and NFAT1 as promising intervention target for psoriasis management.

The cytokine receptor DR3 identifies and promotes the activation of thymic NKT17 cells.

Invariant natural killer T (iNKT) cells correspond to a population of thymus-generated T cells with innate-like characteristics and effector functions. Among the various iNKT subsets, NKT17 is the only subset that produces the proinflammatory cytokine IL-17. But, how NKT17 cells acquire this ability and what would selectively trigger their activation remain incompletely understood. Here, we identified the cytokine receptor DR3 being specifically expressed on thymic NKT17 cells and mostly absent on other thymic iNKT subsets. Moreover, DR3 ligation promoted the in vivo activation of thymic NKT17 cells and provided costimulatory effects upon agonistic α-GalCer stimulation. Thus, we identified a specific surface marker for thymic NKT17 cells that triggers their activation and augments their effector functions both in vivo and in vitro. These findings provide new insights for deciphering the role and function of murine NKT17 cells and for understanding the development and activation mechanisms of iNKT cells in general.

Extrathymic AIRE-Expressing Cells: A Historical Perspective.

Since its discovery, Aire has been the topic of numerous studies in its role as a transcriptional regulator in the thymus where it promotes the "promiscuous" expression of a large repertoire of tissue-restricted antigens (TRAs) that are normally expressed only in the immune periphery. This process occurs in specialized medullary thymic epithelial cells (mTECs) and mediates the elimination of self-reactive T cells or promotes their conversion to the Foxp3+ regulatory T cell lineage, both of which are required for the prevention of autoimmunity. In recent years, there has been increasing interest in the role of extrathymic Aire expression in peripheral organs. The focus has primarily been on the identification of the cellular source(s) and mechanism(s) by which extrathymic AIRE affects tolerance-related or other physiological processes. A cadre of OMICs tools including single cell RNA sequencing and novel transgenic models to trace Aire expression to perform lineage tracing experiments have shed light on a phenomenon that is more complex than previously thought. In this chapter, we provide a deeper analysis of how extrathymic Aire research has developed and progressed, how cellular sources were identified, and how the function of AIRE was determined. Current data suggests that extrathymic AIRE fulfills a function that differs from what has been observed in the thymus and strongly argues that its main purpose is to regulate transcriptional programs in a cell content-dependent manner. Surprisingly, there is data that also suggests a non-transcriptional role of extrathymic AIRE in the cytoplasm. We have arrived at a potential turning point that will take the field from the classical understanding of AIRE as a transcription factor in control of TRA expression to its role in immunological and non-immunological processes in the periphery.

Cooperativity between the orthosteric and allosteric ligand binding sites of RORγt.

Cooperative ligand binding is an important phenomenon in biological systems where ligand binding influences the binding of another ligand at an alternative site of the protein via an intramolecular network of interactions. The underlying mechanisms behind cooperative binding remain poorly understood, primarily due to the lack of structural data of these ternary complexes. Using time-resolved fluorescence resonance energy transfer (TR-FRET) studies, we show that cooperative ligand binding occurs for RORγt, a nuclear receptor associated with the pathogenesis of autoimmune diseases. To provide the crucial structural insights, we solved 12 crystal structures of RORγt simultaneously bound to various orthosteric and allosteric ligands. The presence of the orthosteric ligand induces a clamping motion of the allosteric pocket via helices 4 to 5. Additional molecular dynamics simulations revealed the unusual mechanism behind this clamping motion, with Ala355 shifting between helix 4 and 5. The orthosteric RORγt agonists regulate the conformation of Ala355, thereby stabilizing the conformation of the allosteric pocket and cooperatively enhancing the affinity of the allosteric inverse agonists.

USP25 attenuates anti-GBM nephritis in mice by negative feedback regulation of Th17 cell differentiation.

PURPOSE: This study aimed to elucidate the role of USP25 in a mouse model of anti-glomerular basement membrane glomerulonephritis (anti-GBM GN). METHODS: USP25-deficient anti-GBM GN mice were generated, and their nephritis progression was monitored. Naïve CD4+ T cells were isolated from spleen lymphocytes and stimulated to differentiate into Th1, Th2, and Th17 cells. This approach was used to investigate the impact of USP25 on CD4+ T lymphocyte differentiation in vitro. Furthermore, changes in USP25 expression were monitored during Th17 differentiation, both in vivo and in vitro. RESULTS: USP25-/- mice with anti-GBM GN exhibited accelerated renal function deterioration, increased infiltration of Th1 and Th17 cells, and elevated RORγt transcription. In vitro experiments demonstrated that USP25-/- CD4+ T lymphocytes had a higher proportion for Th17 cell differentiation and exhibited higher RORγt levels upon stimulation. Wild-type mice with anti-GBM GN showed higher USP25 levels compared to healthy mice, and a positive correlation was observed between USP25 levels and Th17 cell counts. Similar trends were observed in vitro. CONCLUSION: USP25 plays a crucial role in mitigating renal histopathological and functional damage during anti-GBM GN in mice. This protective effect is primarily attributed to USP25's ability to inhibit the differentiation of naïve CD4+ T cells into Th17 cells. The underlying mechanism may involve the downregulation of RORγt. Additionally, during increased inflammatory responses or Th17 cell differentiation, USP25 expression is activated, forming a negative feedback regulatory loop that attenuates immune activation.

27-hydroxycholesterol causes cognitive deficits by disturbing Th17/Treg balance and the related immune responses in mild cognitive impairment patients and C57BL/6J mice.

BACKGROUND: Cognitive impairment is associated with dysregulated immune responses. Emerging evidence indicates that Th17 cells and their characteristic cytokine-IL-17 are receiving growing interest in the pathogenesis of cognitive decline. Here, we focus on the involvement of Th17 cells in mild cognitive impairment (MCI) and the possible mechanism of cholesterol metabolite-27-hydroxycholesterol (27-OHC). METHODS: 100 individuals were recruited into the nested case-control study who completed cognition assessment and the detection of oxysterols and Th17-related cytokines in serum. In addition, mice were treated with 27-OHC and inhibitors of RORγt and Foxp3 (Th17 and Treg transcription factors), and the factors involved in Th17/Treg balance and amyloidosis were detected. RESULTS: Our results showed there was enhanced 27-OHC level in serum of MCI individuals. The Th17-related cytokines homeostasis was altered, manifested as increased IL-17A, IL-12p70, IL-23, GM-CSF, MIP-3α and TNF-α but decreased IL-13, IL-28A and TGF-ß1. Further, in vivo experiments showed that 27-OHC induced higher immunogenicity, which increased Th17 proportion but decreased Treg cells in peripheral blood mononuclear cells (PBMCs); Th17 proportions in hippocampus, and IL-17A level in serum and brain were also higher than control mice. The fluorescence intensity of amyloid-ß (Aß) and the precursor of amyloid A amyloidosis-serum amyloid A (SAA) was increased in the brain of 27-OHC-treated mice, and worse learning and memory performance was supported by water maze test results. While by inhibiting RORγt in 27-OHC-loaded mice, Th17 proportions in both PBMCs and hippocampus were reduced, and expressions of IL-17A and TGF-ß1 were down- and up-regulated, respectively, along with a decreased amyloidosis in brain and improved learning and memory decline. CONCLUSIONS: Altogether, our results demonstrate that excessive 27-OHC aggravates the amyloidosis and leads to cognitive deficits by regulating RORγt and disturbing Th17/Treg balance.

Associations between RORγt and T-bet Expressions, clinicopathological indices and survival rate in oral Squamous cell carcinoma patients.

BACKGROUND: Oral cancers are the sixth most common cancers around the world. According to the pivotal role of immune cells in the pathogenesis of oral squamous cell carcinoma (OSCC), as the frequent form of malignant epithelial neoplasm in the oral cavity, we investigated the association between the expression of RORγt and T-bet genes as two transcription factors, clinicopathologic indices, and survival rate. METHODS AND MATERIALS: Forty-two OSCC paraffin embded-blocks tissue samples and their surgical healthy margins (as a control group) were collected. Demographic information like age and gender, and medical history including tumor stage/grade, and following-up time were registered. The RORγt and T-bet expression were assessed by qPCR. The overall survival (OS) and disease free survival (DFS) were analyzed by SPSS V.23 software. RESULTS: The expression of RORγt and T-bet genes in OSCC patients were significantly higher than in surgical healthy margins (P < 0.001). Both expression demonstrated a significant difference between surgical healthy margins and tumor tissues related to gender and clinicopathological indices including stage and grade (P < 0.05). The expression of both genes in stage I patients was significant compared to stage IV (P < 0.05). The relation between expressions, OS, and DFS with clinical stage and histological grade of tumors was not statistically significant (P > 0.05). CONCLUSION: Overexpression of RORγt and T-bet in OSCC patients with higher grade and stage in compare to surgical healthy margin highlighted their critical role in OSCC pathogenesis including oral epithelial cell differentiation, tumorigenesis process, and malignant transformation. Moreover, both mentioned genes can apply as prognostic biomarkers in OSCC patients. We suggest surgical healthy margin be considered as valuable biological area.

Multistrain Probiotics Supplement Alleviates Asthma Symptoms via Increasing Treg Cells Population: A Randomized, Double-Blind, Placebo-Controlled Trial.

INTRODUCTION: The favorable effects of probiotics have been demonstrated in allergic disorders. However, the underlying immunological mechanisms are poorly understood. In the present study, we investigated the improvement of clinical symptoms and immunological balance after receiving probiotics in patients with asthma. METHODS: The present study was a randomized, double-blind, placebo-controlled trial in which 40 patients with asthma were enrolled. They were treated with probiotics or placebo: 1 capsule/day for 8 weeks. Pulmonary function test, percentage of CD4+ CD25+ FoxP3+ Tregs, and gene expression of T-bet, GATA-3, RORγt, and Foxp3 in PBMCs were assessed at baseline and after treatment. RESULTS: Our results showed a significant increase in the expression of FoxP3 and CD4+ CD25+ FoxP3+ Tregs population, while RORγt and GATA3 expression were reduced. In addition, pulmonary function tests showed a significant improvement in forced expiratory volume and forced vital capacity after receiving probiotics. DISCUSSION/CONCLUSION: Our findings demonstrate that 8-week treatment with probiotic supplementation can control T-helper 2-predominant and Th17 pro-inflammatory responses and improve forced vital and forced expiratory volume in asthmatic patients. It seems probiotics can be used besides common treatments for patients with asthma.

T-Cell Immune Responses and Immunological Factors Associated with Coronavirus Disease 2019 Progression as Predictors for the Severity of the Disease in Hospitalized Patients.

INTRODUCTION: The prevalence of coronavirus disease 2019 (COVID-19) has rapidly increased worldwide. More investigation is needed to progress toward understanding the exact role of immune responses in the pathology of the disease, leading to improved anticipation and treatment options. METHODS: In the present study, we examined the relative expression of T-bet, GATA3, RORγt, and FoxP3 transcription factors as well as laboratory indicators in 79 hospitalized patients along with 20 healthy subjects as a control group. In order to make an exact comparison between various degrees of severity of disease, patients were divided into critical (n = 12) and severe (n = 67) groups. To evaluate the expression of genes of interest by performing real-time PCR, blood samples were obtained from each participant. RESULTS: We found a significant increase in the expression of T-bet, GATA3, and RORγt and a reduction in the expression of FoxP3 in the critically ill patients compared to the severe and control groups. Also, we noticed that the GATA3 and RORγt expressions were elevated in the severe group in comparison with healthy subjects. Additionally, the GATA3 and RORγt expressions showed a positive correlation with elevation in CRP and hepatic enzyme concentration. Moreover, we observed that the GATA3 and RORγt expressions were the independent risk factors for the severity and outcome of COVID-19. DISCUSSION: The present study showed that the overexpression of T-bet, GATA3, and RORγt, as well as a decrease in the FoxP3 expression was associated with the severity and fatal outcome of COVID-19.

α-Synuclein induces Th17 differentiation and impairs the function and stability of Tregs by promoting RORC transcription in Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons (DA) and the accumulation of Lewy body deposits composed of alpha-Synuclein (α-Syn), which act as antigenic epitopes to drive cytotoxic T-cell responses in PD. Increased T helper 17 (Th17) cells and dysfunctional regulatory T cells (Tregs) have been reported to be associated with the loss of DA in PD. However, the mechanism underlying the Th17/Treg imbalance remains unknown. METHODS: Here, we examined the percentage of Th17 cells, the percentage of Tregs and the α-Syn level and analysed their correlations in the peripheral blood of PD patients and in the substantia nigra pars compacta (SNpc) and spleen of MPTP-treated mice and A53 transgenic mice. We assessed the effect of α-Syn on the stability and function of Tregs and the differentiation of Th17 cells and evaluated the role of retinoid-related orphan nuclear receptor (RORγt) upregulation in α-Syn stimulation in vivo and in vitro. RESULTS: We found that the α-Syn level and severity of motor symptoms were positively correlated with the increase in Th17 cells and decrease in Tregs in PD patients. Moreover, α-Syn stimulation led to the loss of Forkhead box protein P3 (FOXP3) expression in Tregs, accompanied by the acquisition of IL-17A expression. Increased Th17 differentiation was detected upon α-Syn stimulation when naïve CD4+ T cells were cultured under Th17-polarizing conditions. Mechanistically, α-Syn promotes the transcription of RORC, encoding RORγt, in Tregs and Th17 cells, leading to increased Th17 differentiation and loss of Treg function. Intriguingly, the increase in Th17 cells, decrease in Tregs and apoptosis of DA were suppressed by a RORγt inhibitor (GSK805) in MPTP-treated mice. CONCLUSION: Together, our data suggest that α-Syn promotes the transcription of RORC in circulating CD4+ T cells, including Tregs and Th17 cells, to impair the stability of Tregs and promote the differentiation of Th17 cells in PD. Inhibition of RORγt attenuated the apoptosis of DA and alleviated the increase in Th17 cells and decrease in Tregs in PD.

Increased Pro Th1 And Th17 Transcriptional Activity In Patients With Severe COVID-19.

Background: COVID-19 is known to disrupt immune response and induce hyperinflammation that could potentially induce fatal outcome of the disease. Until now, it is known that interplay among cytokines is rather important for clinical presentation and outcome of COVID-19. The aim of this study was to determine transcriptional activity and functional phenotype of T cells and the relationship between pro- and anti-inflammatory cytokines and clinical parameters of COVID-19 severity. Methods: All recruited patients met criteria for COVID-19 are were divided in four groups according to disease severity. Serum levels of IL-12, IFN-γ, IL-17 and IL-23 were measured, and flow cytometry analysis of T cells from peripheral blood was performed. Results: Significant elevation of IL-12, IFN-γ, IL-17 and IL-23 in stage IV of the disease has been revealed. Further, strong intercorrelation between IL-12, IFN-γ, IL-17 and IL-23 was also found in stage IV of the disease, marking augmented Th1 and Th17 response. Analyses of T cells subsets indicate a noticeable phenotype change. CD4+, but not CD8+ T cells expressed increased transcriptional activity through increased expression of Tbet and RORγT, accompanied with increased percentage of IFN-γ and IL-17 producing T cells. Conclusion: Our results pose a novel hypothesis of the underlying mechanism behind deteriorating immune response in severe cases of COVID-19.

iNKT17 cells play a pathogenic role in ethinylestradiol-induced cholestatic hepatotoxicity.

IL-17 is closely associated with inflammation in intrahepatic cholestasis (IHC). Targeting IL-17 ameliorates IHC in mice. Invariant natural killer T (iNKT) cells are predominantly enriched in the liver and they mediate drug-induced liver injury through their secreted cytokines. However, whether iNKT17 cells are involved in ethinylestradiol (EE)-induced IHC remains unclear. In the present study, the administration of EE (10 mg/kg in vivo and 6.25 µM in vitro) promoted the activation and expansion of iNKT17 cells, which contributed to a novel hepatic iNKT17/Treg imbalance. iNKT cell-deficient Jα18-/- mice and the RORγt inhibitor digoxin (20 µg) alleviated EE-induced cholestatic hepatotoxicity and downregulated the IL-17 signalling pathway. In contrast, the co-administration of EE with recombinant IL-17 (1 µg) to Jα18-/- mice induced cholestatic hepatotoxicity and increased the infiltration of hepatic neutrophils and monocytes. Importantly, the administration of IL-17-/- iNKT cells (3.5 × 105) to Jα18-/- mice resulted in the attenuation of hepatotoxicity and the recruitment of fewer hepatic neutrophils and monocytes than the adoptive transfer of wild-type iNKT cells. These results indicated that iNKT17 cells could exert pathogenic effects. The recruitment and activation of iNKT17 cells could be attributed to the high level of CXCR3 expression on their surface. CXCL10 deficiency ameliorated EE-induced cholestatic liver damage, reduced hepatic CXCR3+ iNKT cells and inhibited RORγt expression. These findings suggest that iNKT17 cells play a key role in EE-induced cholestatic liver injury via CXCR3-mediated recruitment and activation. Our study provides new insights and therapeutic targets for cholestatic diseases.

Natural Geranylated Sulfur-Containing Amides with Inhibitory Effect on Th17 Differentiation.

Chemical investigation of medicinal plant Glycosmis lucida Wall. ex C. C. Huang leaves led to the production of ten compounds (1-10), including two previously unreported geranylated sulfur-containing amides (1 and 2) and eight known ones (3-10). Structural characterization was carried out using comprehensive spectroscopic methods including NMR, MS and CD. The inhibitory effects of all isolates on Th17 differentiation were evaluated, of which compounds 1 and 6 significantly inhibited Th17 differentiation with IC50 values of 0.36 and 1.30 µM, respectively, while both 1 and 6 failed to bind to retinoic acid-related orphan receptor gamma t (RORγt), suggesting that their inhibition of Th17 differentiation is independent of RORγt.

Cornus mas L. Extract Targets the Specific Molecules of the Th17/Treg Developmental Pathway in TNBS-Induced Experimental Colitis in Rats.

Given that one of the crucial events in the pathogenesis of inflammatory bowel disease is the loss of homeostasis between Th17 and Treg cells, targeting the specific molecules of the Th17/Treg axis developmental pathway is a promising strategy for inflammatory bowel disease prevention and treatment. The current study aimed to assess the impact of cornelian cherry (Cornus mas L.) extract, rich in iridoids and polyphenols known for their potential anti-inflammatory activity, at two doses (20 or 100 mg/kg) on the crucial factors for Th17/Treg cell differentiation in the course of experimental colitis and compare this action with that of sulfasalazine. This study was conducted on the biobank colon tissue samples collected during the previous original experiment, in which colitis in rats was induced by trinitrobenzenesulfonic acid (TNBS). The levels of IL-6, RORγt, total STAT3, p-STAT3, and Foxp3 were determined by ELISA. The expression of PIAS3 mRNA was quantified by qPCR. Cornelian cherry extract at a dose of 100 mg/kg counteracted the TNBS-induced elevation of IL-6, RORγt, and p-STAT3 levels and a decrease in Foxp3 level and PIAS3 mRNA expression, while given concomitantly with sulfasalazine was more effective than sulfasalazine alone in reversing the TNBS-induced changes in IL-6, RORγt, total STAT3, p-STAT3, Foxp3 levels, and PIAS3 mRNA expression. The beneficial effect of cornelian cherry extract on experimental colitis may be due to its immunomodulatory activity reflected by the influence on factors regulating the Th17/Treg axis.