NrCAM activates the NF-κB signalling pathway by competitively binding to SUMO-1 and promotes Th17 cell differentiation in Graves' disease.

This study aimed to explore the molecular mechanism of neuronal cell adhesion molecule (NrCAM) by regulating Th17 cell differentiation in the pathogenesis of Graves' disease (GD). Naïve CD4+ T cells were isolated from peripheral blood mononuclear cells of GD patients and healthy control (HC) subjects. During the differentiation of CD4+ T cells into Th17 cells, NrCAM level in GD group was improved. Interference with NrCAM in CD4+ T cells of GD patients decreased the percentage of Th17 cells. NrCAM overexpression in CD4+ T cells of HC subjects increased the percentage of Th17 cells and upregulated p-IκBα, p50, p65, c-Rel protein expressions, and NF-κB inhibitor BAY11-7082 partially reversed NrCAM effect. NrCAM overexpression promoted the degradation of IκBα, and overexpression of small ubiquitin-related modifier 1 (SUMO-1) inhibited IκBα degradation. NrCAM overexpression reduced IκBα binding to SUMO-1. During Th17 cell differentiation in HC group, NrCAM overexpression increased IL-21 levels and secretion, and IL-21 neutralizing antibody reversed this effect. IL-21 level was decreased after p65 interference in CD4+ T cells of HC subjects. p65 interacts with IL-21 promoter region. In conclusion, NrCAM binds to SUMO-1 and increases phosphorylation of IκBα, leading to activation of NF-κB pathway, which promotes Th17 cell differentiation.

Hedgehog signaling pathway regulates Th17 cell differentiation in asthma via IL-6/STAT3 signaling.

Asthma is the most prevalent chronic inflammatory disease of the airways in children. The most prevalent phenotype of asthma is eosinophilic asthma, which is driven by a Th2 immune response and can be effectively managed by inhaled corticosteroid therapy. However, there are phenotypes of asthma with Th17 immune response that are insensitive to corticosteroid therapy and manifest a more severe phenotype. The treatment of this corticosteroid-insensitive asthma is currently immature and requires further attention. The objective of this study is to elucidate the regulation of the Hedgehog signaling pathway in Th17 cell differentiation in asthma. The study demonstrated that both Smo and Gli3, key components of the Hedgehog signaling pathway, were upregulated in Th17 polarization in vitro and in a Th17-dominant asthma model in vivo. Inhibiting Smo with a small molecule inhibitor or genetically knocking down Gli3 was found to suppress Th17 polarization. Smo was found to increase in Th1, Th2, Th17 and Treg polarization, while Gli3 specifically increased in Th17 polarization. ChIP-qPCR analyses indicated that Gli3 can directly interact with IL-6 in T cells, inducing STAT3 phosphorylation and promoting Th17 cell differentiation. Furthermore, the study demonstrated a correlation between elevated Gli3 expression and IL-17A and IL-6 expression in children with asthma. In conclusion, the study demonstrated that the Hedgehog signaling pathway plays an important role in the pathogenesis of asthma, as it regulates the differentiation of Th17 cells through the IL-6/STAT3 signaling. This may provide a potential therapeutic target for corticosteroid-insensitive asthma driven by Th17 cells.

[H3K27me3 Expression Level and Its Epigenetic Regulation Mechanisms in Th17 Cell Differentiation in Patients With Ankylosing Spondylitis]. / å¼ºç›´æ€§è„ŠæŸ±ç‚Žæ‚£è€ H3K27me3è¡¨è¾¾æ°´å¹³åŠå ¶è°ƒæŽ§Th17ç»†èƒžåˆ†åŒ–çš„è¡¨è§‚é—ä¼ æœºåˆ¶.

Objective: To investigate the roles of histone H3K27me3 methylation and its regulatory enzymes JMJD3 and EZH2 in the differentiation of Th17 cells in ankylosing spondylitis (AS), to unveil their potential involvement in the pathogenesis of AS, and to provide new strategies and targets for the clinical treatment of AS by analyzing the methylation state of H3K27me3 and its interactions with Th17-related factors. Methods: A total of 84 AS patients (42 active AS patiens and 42 patients in the stable phase of AS) were enrolled for the study, while 84 healthy volunteers were enrolled as the controls. Blood samples were collected. Peripheral blood mononuclear cells were isolated. ELISA assay was performed to examine Th17 cells and the relevant cytokines IL-21, IL-22, and IL-17. The mRNA expressions of RORc, JAK2, and STAT3 were analyzed by RT-PCR, the protein expressions of RORc, JAK2/STAT3 pathway protein, H3K27me3 and the relevant protease (EZH2 and JMJD3) were determined by Western blot. Correlation between H3K27me3, EZH2 and JMJD3 and the key signaling pathway molecules of Th cell differentiation was analyzed by Pearson correlation analysis. Results: The mRNA expressions of RORc, JAK2, and STAT3 were significantly higher in the active phase group than those in the stable phase group ( P<0.05). The relative grayscale values of H3K27me3 and EZH2 in the active phase group were lower than those of the stable phase group, which were lower than those of the control group, with the differences being statistically significant ( P<0.05). The relative grayscale values of JMJD3, RORc, JAK2, pJAK2, STAT3, and pSTAT3 proteins were significantly higher in the active phase group than those in the stable phase group, which were higher than those in the control group (all P<0.05). The proportion of Th17 and the expression level of inflammatory factors in the active period group were higher than those in the other two groups (P<0.05). H3K27me3 was negatively correlated with RORc, JAK2, STAT3, and IL-17, JMJD3 was positvely correlated with JAK2, STAT3, and IL-17, and EZH2 was negatively correlated with JAK2, STAT3, and IL-17 (all P<0.05). Conclusion: The low expression of H3K27me3 in AS is influenced by the gene loci JMJD3 and EZH2, which can regulate the differentiation of Th17 cells and thus play a role in the pathogenesis and progression of AS.

Class IIa HDAC4 and HDAC7 cooperatively regulate gene transcription in Th17 cell differentiation.

Class II histone deacetylases (HDACs) are important in regulation of gene transcription during T cell development. However, our understanding of their cell-specific functions is limited. In this study, we reveal that class IIa Hdac4 and Hdac7 (Hdac4/7) are selectively induced in transcription, guiding the lineage-specific differentiation of mouse T-helper 17 (Th17) cells from naive CD4+ T cells. Importantly, Hdac4/7 are functionally dispensable in other Th subtypes. Mechanistically, Hdac4 interacts with the transcription factor (TF) JunB, facilitating the transcriptional activation of Th17 signature genes such as Il17a/f. Conversely, Hdac7 collaborates with the TF Aiolos and Smrt/Ncor1-Hdac3 corepressors to repress transcription of Th17 negative regulators, including Il2, in Th17 cell differentiation. Inhibiting Hdac4/7 through pharmacological or genetic methods effectively mitigates Th17 cell-mediated intestinal inflammation in a colitis mouse model. Our study uncovers molecular mechanisms where HDAC4 and HDAC7 function distinctively yet cooperatively in regulating ordered gene transcription during Th17 cell differentiation. These findings suggest a potential therapeutic strategy of targeting HDAC4/7 for treating Th17-related inflammatory diseases, such as ulcerative colitis.

Targeting Aquaporin-3 Attenuates Skin Inflammation in Rosacea.

Rosacea is a common inflammatory skin disorder mediated by the dysregulation of both keratinocytes and T cells. Here, we report that aquaporin 3 (AQP3), a channel protein that mediates the transport of water/glycerol, was highly expressed in the epidermis and CD4+ T cells of both rosacea patients and experimental mice. Specifically, AQP3 deletion blocked the development of rosacea-like skin inflammation in model mice with LL37-induced rosacea-like disease. We also present mechanistic evidence showing that AQP3 was essential to the activation of NF-κB signaling and subsequent production of disease-characteristic chemokines in keratinocytes. Moreover, we show that AQP3 was upregulated during T cell differentiation and promotes helper T (Th) 17 differentiation possibly via the activation of STAT3 signaling. Our findings reveal that AQP3-mediated activation of NF-κB in keratinocytes and activation of STAT3 in CD4+ T cells acted synergistically and contributed to the inflammation in rosacea.

Rheum palmatum L. and Salvia miltiorrhiza Bge. Alleviates Acute Pancreatitis by Regulating Th17 Cell Differentiation: An Integrated Network Pharmacology Analysis, Molecular Dynamics Simulation and Experimental Validation.

OBJECTIVE: To identify the core targets of Rheum palmatum L. and Salvia miltiorrhiza Bge., (Dahuang-Danshen, DH-DS) and the mechanism underlying its therapeutic efficacy in acute pancreatitis (AP) using a network pharmacology approach and validate the findings in animal experiments. METHODS: Network pharmacology analysis was used to elucidate the mechanisms underlying the therapeutic effects of DH-DS in AP. The reliability of the results was verified by molecular docking simulation and molecular dynamics simulation. Finally, the results of network pharmacology enrichment analysis were verified by immunohistochemistry, Western blot analysis and real-time quantitative PCR, respectively. RESULTS: Sixty-seven common targets of DH-DS in AP were identified and mitogen-activated protein kinase 3 (MAPK3), Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), protein c-Fos (FOS) were identified as core targets in the protein interaction (PPI) network analysis. Gene ontology analysis showed that cellular response to organic substance was the main functions of DH-DS in AP, and Kyoto Encyclopedia of Genes and Genomes analysis showed that the main pathway included Th17 cell differentiation. Molecular docking simulation confirmed that DH-DS binds with strong affinity to MAPK3, STAT3 and FOS. Molecular dynamics simulation revealed that FOS-isotanshinone II and STAT3-dan-shexinkum d had good binding capacity. Animal experiments indicated that compared with the AP model group, DH-DS treatment effectively alleviated AP by inhibiting the expression of interleukin-1ß, interleukin-6 and tumor necrosis factor-α, and blocking the activation of Th17 cell differentiation (P<0.01). CONCLUSION: DH-DS could inhibit the expression of inflammatory factors and protect pancreatic tissues, which would be functioned by regulating Th17 cell differentiation-related mRNA and protein expressions.

PCSK9 inhibition ameliorates experimental autoimmune myocarditis by reducing Th17 cell differentiation through LDLR/STAT-3/ROR-γt pathway.

Proprotein convertase subtilisin kexin type 9 (PCSK9) was characterized as a protein regulating circulating cholesterol metabolism; however, recent studies demonstrated a role for PCSK9 in inflammatory and autoimmune diseases unrelated to cholesterol alterations. The implication of PCSK9 in myocarditis is unclear and we aim at investigating the roles and mechanisms of PCSK9 in myocarditis. Male BALB/c mice received subcutaneous immunization with MyHC-α peptide on days 0 and 7 to establish the experimental autoimmune myocarditis (EAM) model. PCSK9 inhibitor, evolocumab, was administered subcutaneously once a week starting on day 0 and all mice were euthanized on day 21. Our results showed that PCSK9 inhibition ameliorated the cardiac inflammation of EAM mice. PCSK9 inhibition reduced both the levels of cardiac and peripheral blood PCSK9. We found that CD4+ T cells, CD8+ T cells, macrophages, and cardiomyocytes in the heart of EAM mice could express PCSK9. PCSK9 inhibition decreased the differentiation of cardiac Th17 cells by lowering ROR-γt levels but had no effects on Th1, Th2, and Treg cell differentiation. In vitro experiments of CD4+ T cells, we found that PCSK9 directly promoted Th17 cell differentiation through LDLR/STAT3/ROR-γt pathway. Collectively, we demonstrated that PCSK9 inhibition ameliorated the severity of EAM mice by reducing Th17 cell differentiation. PCSK9 is a promising target for treating myocarditis.

AhR may be involved in Th17 cell differentiation in chronic hepatitis B.

Th17 cells which are crucial for host immunity have been demonstrated to increase HBV infection. However, the mechanism of the Th17 cell increase is unknown. Hence, the mechanism of Th17 cell enhancement is important to provide a theoretical foundation for chronic hepatitis B immunotherapy. This study included 15 instances in the healthy control (HC) and 15 cohorts in the chronic hepatitis B (CHB). Their CD4+ T cells were isolated from their peripheral blood and then subjected to RNA transcriptome sequencing. Then, to identify target genes linked to Th17-cell differentiation, DEGs associated with CHB were convergent with the Th17-cell-associated genes from the KEGG database. Hub genes of DEG and target genes linked to Th17 cells were analysed for correlation. The AhR-related genes were located using the GeneMANIA database. To analyse the function of the genes, GO and KEGG pathways were employed. Protein-protein interaction network analysis employed the Metascape, STRING and Cytoscape databases. Finally, Western blotting and RT-qPCR were used to validate AhR. A total of 348 differential genes were identified in CHB patients. CytoHubba was used for screening five hub genes associated with CHB: CXCL10, RACGAP1, TPX2, FN1 and GZMA. This study aimed to determine the mechanism of elevated Th17 cells in CHB. As a result, further investigation using the convergence of DGEs and Th17 cell-related genes identified three target genes: AhR, HLA-DQA1 and HLA-DQB1, all of which were elevated in CHB. The three genes were primarily involved in immune response-related processes, according to the GO enrichment analysis. Correlation analysis of CXCL10, RACGAP1, TPX2, FN1 and GZMA genes with AhR, HLA-DQA1 and HLA-DQB1 revealed that AhR was positively associated with CXCL10 and GZMA genes, which best respond to the severity of CHB disease. Combined with the role of AhR in Th17 cell differentiation, the genes AhR was chosen for confirmation by RT-qPCR and WB in this study. The results showed that the CHB group had higher expression levels of AhR at both RT-qPCR and WB levels. Furthermore, this study's findings revealed that AhR may contribute to the development of CHB by affecting the differentiation of Th17 cells.

MIF promotes Th17 cell differentiation in Hashimoto's thyroiditis by binding HVEM and activating NF-κB signaling pathway.

Hashimoto's thyroiditis is a typical thyroid autoimmune disease and Th17 cells are crucial in its development. In recent years, MIF (Macrophage Migration Inhibitory Factor) has been found to promote the secretion of IL-17A and the production and differentiation of Th17 cells. However, the specific mechanism of it remains unclear. Here, we found that the expression of MIF, IL-17A and HVEM (Herpes Virus Entry Mediator) were up-regulated in HT patients. The proportion of Th17 cells in peripheral blood mononuclear cells was positively correlated with the serum MIF protein level. We further found that the expression of HVEM and the phosphorylation level of NF-κB in peripheral blood mononuclear cells of HT patients were significantly increased. Therefore, we speculated that MIF promotes Th17 cell differentiation through HVEM and NF-κB signaling pathways. Further mechanism studies showed that MIF could directly bind to HVEM, and the stimulation of rhMIF in vitro could increase the expression of HVEM and activate NF-κB signaling pathways to promote Th17 cell differentiation. After blocking HVEM with HVEM antibody, the effect of MIF on Th17 cell differentiation disappeared. The results above show that the differentiation of Th17 cells is promoted by MIF combined with HVEM through NF-κB signaling pathways. Our research provides a new theory to the regulation mechanism of Th17 cell differentiation and gives hint to new potential therapeutic targets for HT.

Liangxue Jiedu formula improves imiquimod-induced psoriasiform dermatitis with circadian desynchrony by regulating Th17 cell differentiation based on network pharmacological analysis.

ETHNOPHARMACOLOGICAL RELEVANCE: Liangxue Jiedu formula (LXJDF) is an effective traditional Chinese medicine (TCM) formula for treating psoriasis of blood-heat syndrome and has been used in clinics for decades. AIM OF THE STUDY: This study aimed to discover the mechanism of LXJDF in psoriasis and the circadian clock by network pharmacology and experimental studies. MATERIALS AND METHODS: The compounds of LXJDF were obtained from the TCMSP and BATMAN-TCM databases. The genes related to psoriasis and circadian rhythm/clock were identified by the OMIM and GeneCards databases. Then, target genes were integrated by Venn and analyzed by the String, CytoNCA, DAVID (GO and KEGG) databases, and the network was constructed using Cytoscape. Mice were raised under light disturbance for fourteen days. On the eighth day, mouse dorsal skin was shaved and smeared with 62.5 mg 5% imiquimod at 8:00 (ZT0) for six successive days. Mice were randomly divided into the model, LXJDF-H (49.2 g/kg·bw), LXJDF-L (24.6 g/kg·bw), and positive drug (dexamethasone) groups. Other mice were smeared with Vaseline under the normal light cycle as the control. The drug of each group was administered at 10:00 (ZT2) and 22:00 (ZT14). The skin lesions were observed, and PASI was scored daily. HE and immunofluorescence were used to measure pathological morphology. Th17 cytokines in serum and skin were measured by flow cytometry and qPCR. Circadian clock gene and protein expression levels were determined by qPCR and Western blotting. RESULTS: We found 34 potential targets of LXJDF in the treatment of psoriasis and circadian rhythm and confirmed their importance by topology analysis. KEGG pathway analysis revealed that the two major pathways were Th17 cell differentiation and the HIF-1 signaling pathway. At ZT2 and ZT14, LXJDF improved IMQ-induced light disturbance mouse skin lesions, including alleviating scales, erythema, and infiltration, reducing PASI, and inhibiting keratinocyte hyperproliferation and parakeratosis. LXJDF reduced IL-17A, IL-17F, TNF-α, and IL-6 in serum at ZT2 and increased IL-10 at ZT2 and ZT14. LXJDF downregulated the expression of IL-17A and IL-17F in skin. At ZT2, LXJDF significantly upregulated CLOCK and REV-ERBα expression and downregulated HIF-1α expression. At ZT14, LXJDF decreased HIF-1α and RORγt expression and significantly increased REV-ERBα expression. CONCLUSION: LXJDF improves psoriasis dermatitis with circadian rhythm disorders by regulating Th17 cell differentiation.

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.

SGLT2 inhibitor, canagliflozin, ameliorates cardiac inflammation in experimental autoimmune myocarditis.

Myocarditis is an inflammatory cardiovascular disease which contributes to dilated cardiomyopathy (DCM) and heart failure. Canagliflozin (CANA) exerts anti-inflammatory and cardioprotective effects in heart failure besides its hypoglycemic effect. However, the role of CANA in myocarditis has not been elucidated. In this work, CANA treatment markedly alleviated cardiac inflammation and improved cardiac function in experimental autoimmune myocarditis (EAM) mice induced by α-myosin-heavy chain peptides. The expressions of NLRP3 inflammasome complexes (NLRP3, ASC, and Caspase-1) and their downstream molecules (IL-1ß, IL-18) were significantly downregulated by CANA, accompanied with reduced Th17 cell infiltration in hearts. Furthermore, Bax/Bcl-2 ratio, Cleaved Caspase-3 protein level and the percentage of TUNEL-positive myocardial cells, which usually indicated apoptosis, were reduced by CANA treatment. These findings suggest CANA could be a valuable medication for myocarditis treatment.

Vitamin D3 reverses the transcriptional profile of offspring CD4+ T lymphocytes exposed to intrauterine inflammation.

Chorioamnionitis profoundly influences multiple fetal organs as well as the immune system. Maternal vitamin D (VitD) supplementation may modulate the immune function of offspring. Here, we sought to uncover the immunomodulatory potential of intrauterine inflammation and VitD in offspring CD4+ T cells. Pregnant C57BL/6 mice were treated with intrauterine lipopolysaccharide (LPS) injections, with or without VitD. Splenic CD4+ T cells were negatively selected using anti-biotin microbeads at 28 days after birth. Differentially expressed genes (DEGs) in the offspring CD4+ T cells were identified via RNA sequencing. In total, 181 DEGs induced by LPS exposure were identified in offspring CD4+ T cells. Furthermore, 2461 DEGs were detected after VitD supplementation in addition to LPS exposure. VitD supplementation showed an unexpected ability to counteract the LPS-induced transcriptional responses. VitD supplementation downregulated lymphocyte differentiation (GO: 0030098) and lymphocyte activation (GO: 0046649), and upregulated the responses to viruses (GO: 0009615) and bacteria (GO:0009617) in offspring CD4+ T cells with intrauterine LPS exposure. In addition, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that several pathways, including the T cell receptor signaling pathway, the mitogen-activated protein kinase (MAPK) signaling pathway, Th17 cell differentiation, and autophagy, were downregulated by intrauterine VitD intervention following LPS exposure. Subsequently, we confirmed the counteracting effect of VitD against LPS on the expression of several genes (Insr, Foxo1, and Peli1) using qRT-PCR and western blot analyses. We also demonstrated that intrauterine VitD supplementation interferes with offspring Th17 cell differentiation induced by intrauterine LPS exposure. Our study revealed that VitD reverses the transcriptional and Th17 differential profiles of offspring CD4+ T lymphocytes induced by intrauterine LPS, and indicated the contribution of maternal VitD supplementation to immune protection in offspring affected by intrauterine inflammation.

Ursolic acid inhibits Th17 cell differentiation via STAT3/RORγt pathway and suppresses Schwann cell-mediated Th17 cell migration by reducing CXCL9/10 expression.

Th17 cells represent important immune cells. Ursolic acid (UA) can regulate immune cell activities. This study was aimed to explore the effects of UA on Th17 cell differentiation and Schwann cell(SCs)-mediated migration and the potential mechanism. Naïve CD4+ T cells were isolated from rat peripheral blood, induced for Th17 cell differentiation, and treated with UA. The proportion of Th17 cells was detected by flow cytometry assay. SCs were co-cultured with Th17 cells. Th17 cell migration was detected by Transwell assay. The molecule expression was determined by Western blot and qRT-PCR. UA inhibited the Th17 cell differentiation and suppressed the STAT3/RORγt pathway. STAT3 overexpression up-regulated p-STAT3 and RORγt expression and promoted Th17 cell differentiation under the UA treatment. In LPS- and IFN-γ-stimulated-SCs, UA suppressed the expression of chemokines CXCL9/10, but had no significant effect of CCL20 expression. The expression CXCL9/10 receptor CXCR3 was higher in Th17 cells than that in Treg cells, while the expression CCL20 receptor CCR6 was lower in Th17 cells than that in Treg cells. UA, anti-CXCR3, and anti-CCR6 treatment inhibited SCs-mediated Th17 cell migration, and anti-CXCR3 exerted stronger inhibitory effect than Anti-CCR6. UA inhibited Th17 cell differentiation through STAT3/RORγt pathway and suppressed Th17 cell migration through down-regulating CXCL9/10 expression in SCs.

MicroRNA-Messenger RNA Regulatory Network Mediates Disrupted TH17 Cell Differentiation in Depression.

Accumulating evidence indicates an important role for microRNA (miRNA)-messenger RNA (mRNA) regulatory networks in human depression. However, the mechanisms by which these networks act are complex and remain poorly understood. We used data mining to identify differentially expressed miRNAs from GSE81152 and GSE152267 datasets, and differentially expressed mRNAs were identified from the Netherlands Study of Depression and Anxiety, the GlaxoSmithKline-High-Throughput Disease-specific target Identification Program, and the Janssen-Brain Resource Company study. We constructed a miRNA-mRNA regulatory network based on differentially expressed mRNAs that intersected with target genes of differentially expressed miRNAs, and then performed bioinformatics analysis of the network. The key candidate genes were assessed in the prefrontal cortex of chronic social defeat stress (CSDS) depression mice by quantitative real-time polymerase chain reaction (qRT-PCR). Three differentially expressed miRNAs were commonly identified across the two datasets, and 119 intersecting differentially expressed mRNAs were identified. A miRNA-mRNA regulatory network including these three key differentially expressed miRNAs and 119 intersecting differentially expressed mRNAs was constructed. Functional analysis of the intersecting differentially expressed mRNAs revealed that an abnormal inflammatory response characterized by disturbed T-helper cell 17 (Th17) differentiation was the primary altered biological function. qRT-PCR validated the decreased expression of Th17 cell differentiation-related genes, including interleukin (IL)17A, IL21, IL22, and IL1ß, and the increased expression of retinoic acid receptor-related orphan receptor gamma-t (RORγt) in CSDS mice, which showed significant depressive- and anxiety-like behaviors. This study indicates that an abnormal inflammatory response characterized by disturbed Th17 cell differentiation is the primary altered biological process in major depressive disorder. Our findings indicate possible biomarkers and treatment targets and provide novel clues to understand the pathogenesis of major depressive disorder.

KT2 alleviates ulcerative colitis by reducing Th17 cell differentiation through the miR-302c-5p/STAT3 axis.

BACKGROUND: The abnormal differentiation of Th17 cells aggravates ulcerative colitis (UC). Antimicrobial peptides (AMPs) exert pivotal protection functions against UC. KT2 is a cationic AMP that mediates colon cancer development. However, KT2's function in UC remains unclear. METHODS: The UC mouse model was induced by administering 2.5% dextran sulfate sodium, and the mice were given an enema of KT2. KT2's function in UC and Th17 cell differentiation in vivo was evaluated through various molecular experiments. The KT2's function in Th17 cell differentiation in vitro was evaluated by the proportion of CD4+ IL-17+ T cells, IL-17 levels, and RORγt expression levels. Meanwhile, the mechanism was assessed through quantitative real-time PCR, various loss-of-function assays, and dual-luciferase reporter gene assay. RESULTS: KT2 restrained Th17 cell differentiation in both in vivo and in vitro UC models and slowed the UC process. KT2 elevated miR-302c-5p expression, as well as restrained Th17 cell differentiation by increasing miR-302c-5p. Meanwhile, miR-302c-5p interacted with the signal transducer and activator of transcription 3 (STAT3) and negatively regulated its expression. Furthermore, our data revealed that KT2 restrained the activation of STAT3 by elevating miR-302c-5p, thereby inhibiting Th17 cell differentiation. CONCLUSION: KT2 alleviates UC by repressing Th17 cell differentiation through the miR-302c-5p/STAT3 axis.

HIPK2 directs cell type-specific regulation of STAT3 transcriptional activity in Th17 cell differentiation.

SignificanceSTAT3 (signal transducer and activator of transcription 3) is a master transcription factor that organizes cellular responses to cytokines and growth factors and is implicated in inflammatory disorders. STAT3 is a well-recognized therapeutic target for human cancer and inflammatory disorders, but how its function is regulated in a cell type-specific manner has been a major outstanding question. We discovered that Stat3 imposes self-directed regulation through controlling transcription of its own regulator homeodomain-interacting protein kinase 2 (Hipk2) in a T helper 17 (Th17) cell-specific manner. Our validation of the functional importance of the Stat3-Hipk2 axis in Th17 cell development in the pathogenesis of T cell-induced colitis in mice suggests an approach to therapeutically treat inflammatory bowel diseases that currently lack a safe and effective therapy.

Catalpol Inhibits Tregs-to-Th17 Cell Transdifferentiation by Up-Regulating Let-7g-5p to Reduce STAT3 Protein Levels.

PURPOSE: Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease, and Th17 cells are key factors in the pathogenesis of human inflammatory conditions, such as RA. Catalpol (CAT), a component in Rehmanniae Radix (RR), has been found to regulate human immunity. However, the effects of CAT on Th17 cell differentiation and improvement of RA are not clear. MATERIALS AND METHODS: Collagen-induced arthritis (CIA) mice were constructed to detect the effects of CAT on arthritis and Th17 cells. The effect of CAT on Th17 differentiation was evaluated with let-7g-5p transfection experiments. Flow cytometry was used to detect the proportion of Th17 cells after CAT treatment. Levels of interleukin-17 and RORγt were assessed by qRT-PCR and enzyme-linked immunosorbent assay. The expression of signal transducer and activator of transcription 3 (STAT3) was determined by qRT-PCR and Western blot. RESULTS: We found that the proportion of Th17 cells was negatively associated with let-7g-5p expression in CIA mice. In in vitro experiments, CAT suppressed traditional differentiation of Th17 cells. Simultaneously, CAT significantly decreased Tregs-to-Th17 cells transdifferentiation. Our results demonstrated that CAT inhibited Tregs-to-Th17 cells transdifferentiation by up-regulating let-7g-5p and that the suppressive effect of CAT on traditional differentiation of Th17 cells is not related with let-7-5p. CONCLUSION: Our data indicate that CAT may be a potential modulator of Tregs-to-Th17 cells transdifferentiation by up-regulating let-7g-5p to reduce the expression of STAT3. These results provide new directions for research into RA treatment.

Norcantharidin ameliorates the development of murine lupus via inhibiting the generation of IL-17 producing cells.

Systemic lupus erythematosus (SLE) is a devastating autoimmune disorder associated with severe organ damage. The abnormality of T cell apoptosis is considered as an important pathogenetic mechanism of SLE. Norcantharidin (NCTD), a derivative of Cantharidin, is an efficacious anti-cancer drug by inhibiting cell proliferation and inducing cell apoptosis. Besides, NCTD has also been proved to protect the function of kidneys, while damaged renal function is the most important predictor of morbidity and mortality in SLE. All these suggest the potential effects of NCTD in SLE treatment. In this study we investigated whether NCTD exerted therapeutic effects in a mouse SLE model. Lupus prone female MRL/lpr mice were treated with NCTD (1, 2 mg·kg-1·d-1, ip) for 8 weeks. We showed that NCTD administration significantly decreased mortality rate, diminished the expression of anti-dsDNA IgG antibody, a diagnostic marker for SLE, as well as restored renal structure and function in MRL/lpr mice. Moreover, NCTD administration dose-dependently inhibited lymphoproliferation and T cell accumulation in the spleens of MRL/lpr mice. We further revealed that NCTD specifically inhibited DN T cell proliferation and Th17 cell differentiation both via blocking activation of signal transducer and activator of transcription 3 (STAT3) signaling pathway. On the other hand, NCTD did not affect T cell apoptosis in MRL/lpr mice. Taken together, our data suggest that NCTD may be as a promising therapeutic drug through targeting T cells for the treatment of SLE.

Th17 cell differentiation induced by cytopathogenic biotype BVDV-2 in bovine PBLCs.

BACKGROUND: Bovine viral diarrhea virus (BVDV) is a major pathogen that causes bovine viral diarrhea/mucosal disease (BVD-MD), which has become a global infectious disease due to its wide spread and the lack of effective treatment. The process of BVDV infection is complex. Once infected, host immune cells are activated and modulated. As a major immune cell, peripheral blood lymphocyte cells (PBLCs) are the primary target of BVDV. In order to further understand the mechanism of BVDV- host interaction, the expression profiles of host lymphocytes mRNAs associated with BVDV infection were investigated by transcriptomic sequencing analysis. RESULTS: The transcriptomic sequencing analysis was performed on bovine PBLCs infected with CP BVDV-2 GS2018 after 12 h of infection. Gene expression profiling demonstrated that 1052 genes were differentially expressed in GS2018 infected PBLCs compared with the control group. Of these genes, 485 genes were up-regulated and 567 were down-regulated. The 19 differential expressed genes (DEGs) were selected for validation using quantitative real-time PCR and the results were consistent with the results of RNA-Seq. Gene ontology enrichment and KEGG pathway analysis showed that 1052 DEGs were significantly enriched in 16 pathways, including cytokine-cytokine receptor interaction, IL17, PI3K-Akt, MAPK and TNF signaling pathway. PPI network analysis showed that IL17A, IFN-γ and TNF-α interacted with various proteins and may play crucial roles in BVDV-2 infection. Of note, we confirmed that GS2018 induced Th17 cell differentiation in PBLCs and persistently increased the expression levels of IL17A. In turn, the replication of GS2018 was inhibited by IL17A. CONCLUSION: In this study, the transcription changes of DEGs related to host immune responses in bovine PBLCs were caused by CP BVDV-2 infection. In particular, the effector molecules IL17A of Th17 cells were significantly up-regulated, which inhibited viral replication. These results will contribute to exploration and further understanding of the host immune response mechanism and interaction between host and BVDV-2.