Proteomic Analyses of Human Regulatory T Cells Reveal Adaptations in Signaling Pathways that Protect Cellular Identity.

To obtain a molecular definition of regulatory T (Treg) cell identity, we performed proteomics and transcriptomics on various populations of human regulatory and conventional CD4+ T (Tconv) cells. A protein expression signature was identified that defines all Treg cells, and another signature that defines effector Treg cells. These signatures could not be extrapolated from transcriptome data. Unique cell-biological and metabolic features in Treg cells were defined, as well as specific adaptations in cytokine, TCR, and costimulatory receptor signaling pathways. One such adaptation-selective STAT4 deficiency-prevented destabilization of Treg cell identity and function by inflammatory cytokines, while these signals could still induce critical transcription factors and homing receptors via other pathways. Furthermore, our study revealed surface markers that identify FOXP3+CD4+ T cells with distinct functional properties. Our findings suggest that adaptation in signaling pathways protect Treg cell identity and present a resource for further research into Treg cell biology.

An IL-23-STAT4 pathway is required for the proinflammatory function of classical dendritic cells during CNS inflammation.

Although many cytokine pathways are important for dendritic cell (DC) development, it is less clear what cytokine signals promote the function of mature dendritic cells. The signal transducer and activator of transcription 4 (STAT4) promotes protective immunity and autoimmunity downstream of proinflammatory cytokines including IL-12 and IL-23. In experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), Stat4-/- mice are resistant to the development of inflammation and paralysis. To define whether STAT4 is required for intrinsic signaling in mature DC function, we used conditional mutant mice in the EAE model. Deficiency of STAT4 in CD11c-expressing cells resulted in decreased T cell priming and inflammation in the central nervous system. EAE susceptibility was recovered following adoptive transfer of wild-type bone marrow-derived DCs to mice with STAT4-deficient DCs, but not adoptive transfer of STAT4- or IL-23R-deficient DCs. Single-cell RNA-sequencing (RNA-seq) identified STAT4-dependent genes in DC subsets that paralleled a signature in MS patient DCs. Together, these data define an IL-23-STAT4 pathway in DCs that is key to DC function during inflammatory disease.

Autocrine Loop Involving IL-6 Family Member LIF, LIF Receptor, and STAT4 Drives Sustained Fibroblast Production of Inflammatory Mediators.

Fibroblasts are major contributors to and regulators of inflammation and dominant producers of interleukin-6 (IL-6) in inflammatory diseases like rheumatoid arthritis. Yet, compared to leukocytes, the regulation of inflammatory pathways in fibroblasts is largely unknown. Here, we report that analyses of genes coordinately upregulated with IL-6 pointed to STAT4 and leukemia inhibitory factor (LIF) as potentially linked. Gene silencing revealed that STAT4 was required for IL-6 transcription. STAT4 was recruited to the IL-6 promoter after fibroblast activation, and LIF receptor (LIFR) and STAT4 formed a molecular complex that, together with JAK1 and TYK2 kinases, controlled STAT4 activation. Importantly, a positive feedback loop involving autocrine LIF, LIFR, and STAT4 drove sustained IL-6 transcription. Besides IL-6, this autorine loop also drove the production of other key inflammatory factors including IL-8, granulocyte-colony stimulating factor (G-CSF), IL-33, IL-11, IL-1α, and IL-1ß. These findings define the transcriptional regulation of fibroblast-mediated inflammation as distinct from leukocytes.

A family-wide assessment of latent STAT transcription factor interactions reveals divergent dimer repertoires.

The conversion of signal transducer and activator of transcription (STAT) proteins from latent to active transcription factors is central to cytokine signaling. Triggered by their signal-induced tyrosine phosphorylation, it is the assembly of a range of cytokine-specific STAT homo- and heterodimers that marks a key step in the transition of hitherto latent proteins to transcription activators. In contrast, the constitutive self-assembly of latent STATs and how it relates to the functioning of activated STATs is understood less well. To provide a more complete picture, we developed a co-localization-based assay and tested all 28 possible combinations of the seven unphosphorylated STAT (U-STAT) proteins in living cells. We identified five U-STAT homodimers-STAT1, STAT3, STAT4, STAT5A, and STAT5B-and two heterodimers-STAT1:STAT2 and STAT5A:STAT5B-and performed semi-quantitative assessments of the forces and characterizations of binding interfaces that support them. One STAT protein-STAT6-was found to be monomeric. This comprehensive analysis of latent STAT self-assembly lays bare considerable structural and functional diversity in the ways that link STAT dimerization before and after activation.

In-silico assessment of novel peptidomimetics inhibitor targeting STAT3 and STAT4 N-terminal domain dimerization: A comprehensive study using molecular docking, molecular dynamics simulation, and binding free energy analysis.

Dysregulation in Janus kinase-Signal Transducer and Activation of Transcription (JAK-STAT) pathway is closely linked to various cancer types. The N-terminal domain (NTD) of STAT proteins, upon dimerization, assumes a multifaceted role with remarkable adaptability in mediating interactions between proteins. Consequently, the strategic targeting of the N-terminal domain of STATs has emerged as a promising tactic for disrupting dimerization and impeding the translocation of STAT proteins. In this study, we have deployed an integrated in-silico methodology to rationally design Peptidomimetic foldamers as inhibitors of the N-terminal domains of STAT3 and STAT4, with the objective of disrupting protein dimerization. Consequently, we have judiciously designed a series of peptidomimetics that encompass ß3-amino acids, bearing side chains that mimic the residues within interface II of the dimeric structures of the NTDs. Employing molecular docking techniques; we have assessed the binding affinity of these designed peptidomimetics toward both the NTDs. Furthermore, we have conducted an evaluation of the stability and conformational alterations within the docked complexes over an extensive Molecular Dynamics, subsequently computing the binding free energy utilizing MM/PBSA calculations. Our findings unequivocally demonstrate that the peptidomimetic foldamers we have devised (Peptide-A, Peptide-B, and Peptide-C) exhibit a propensity to bind to and impede the dimerization process of the NTDs of both STAT3 and STAT4. These outcomes serve to underscore the potential of these meticulously designed peptidomimetics as potential candidates meriting further exploration in the realm of cancer prevention and management.

Quercetin regulates dendritic cell activation by targeting STAT4 in the treatment of experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) is a class of autoimmune diseases mainly caused by the immune system attacking the myelin sheath of the axons in the nervous system. Although the pathogenesis of MS is complex, studies have shown that dendritic cells (DCs) play a vital role in the pathogenesis of MS. Quercetin (QU) has a unique advantage in clinical application, especially for treating autoimmune diseases. However, the mechanism of QU in the treatment of experimental autoimmune encephalomyelitis (EAE) remains unclear. In this study, we explore the potential role of QU in EAE. Finally, we find that QU has anti-inflammatory activities and neural protective effects in EAE. The experimental results suggest that the cellular basis for QU's function is to inhibit the activation of DCs while modulating the Th17 cell differentiation in the co-culture system. Further, QU may target STAT4 to inhibit its activation in DCs. This work will be of great significance for the future development and utilization of QU.

TOX, TWIST1, STAT4, and SATB1 protein expressions in early-stage mycosis fungoides.

BACKGROUND: Diagnosis of early mycosis fungoides (eMF) is challenging and often delayed as many of its clinical and histopathologic features may mimic various benign inflammatory dermatoses (BIDs). The products of the thymocyte selection-associated high mobility group box (TOX), twist family BHLH transcription factor 1 (TWIST1), signal transducer and activator of transcription 4 (STAT4), and special AT-rich sequence-binding protein 1 (SATB1) genes function as transcription factors and are involved in the pathogenesis of MF. OBJECTIVES: We aim to determine the diagnostic value of TOX, TWIST1, STAT4, and SATB1 protein expressions in eMF. METHODS: This non-randomized, controlled, prospective analytic study was conducted by performing immunohistochemistry staining with TOX, TWIST1, STAT4, and SATB1 polyclonal antibodies in lesional skin biopsies of eMF and BID patients. Nuclear staining of lymphocytes was compared between eMF and BIDs, and the capacity of these antibodies to predict eMF was determined. RESULTS: Immunostainings with anti-TWIST1 showed an increase in protein expression (p = 0.003) and showed a decrease with anti-SATB1 antibodies in eMF compared to BIDs (p = 0.005) while anti-TOX and anti-STAT4 antibodies did not exhibit significant differences (p = 0.384; p = 0.150). Receiver operating characteristic analysis showed that immunohistochemical evaluations of TWIST1 and SATB1 protein expressions can differentiate eMF (area under the curve [AUC]: 0.728, 95% confidence interval [CI]: 0.605-0.851, p = 0.002; AUC: 0.686, 95% CI: 0.565-0.807, p = 0.013). CONCLUSIONS: TWIST1 and SATB1 are potential diagnostic markers for the histologic diagnosis of eMF.

Regulation of STAT1 and STAT4 Expression by Growth Factor and Interferon Supplementation in Sjögren's Syndrome Cell Culture Models.

Our goal was to investigate the effects of epidermal growth factor (EGF) and interferons (IFNs) on signal transducer and activator of transcription STAT1 and STAT4 mRNA and active phosphorylated protein expression in Sjögren's syndrome cell culture models. iSGECs (immortalized salivary gland epithelial cells) and A253 cells were treated with EGF, IFN-alpha, -beta, -gamma, or mitogen-activated protein kinase p38 alpha (p38-MAPK) inhibitor for 0-24-48-72 h. STAT1 and STAT4 mRNA expression was quantified by qRT-PCR. Untreated and treated cells were compared using the delta-delta-CT method based on glyceraldehyde-3-phosphate dehydrogenase (GAPDH) normalized relative fold changes. phospho-tyrosine-701-STAT1 and phospho-serine-721-STAT4 were detected by Western blot analysis. STAT4 mRNA expression decreased 48 h after EGF treatment in A253 cells, immortalized salivary gland epithelial cells iSGECs nSS2 (sicca patient origin), and iSGECs pSS1 (anti-SSA negative Sjögren's Syndrome patient origin). EGF and p38-MAPK inhibitor decreased A253 STAT4 mRNA levels. EGF combined with IFN-gamma increased phospho-STAT4 and phospho-STAT1 after 72 h in all cell lines, suggesting additive effects for phospho-STAT4 and a major effect from IFN-gamma for phospho-STAT1. pSS1 and nSS2 cells responded differently to type I and type II interferons, confirming unique functional characteristics between iSGEC cell lines. EGF/Interferon related pathways might be targeted to regulate STAT1 and STAT4 expression in salivary gland epithelial cells. Further investigation is required learn how to better target the Janus kinases/signal transducer and activator of transcription proteins (JAK/STAT) pathway-mediated inflammatory response in Sjögren's syndrome.

Harnessing Metformin's Immunomodulatory Effects on Immune Cells to Combat Breast Cancer.

Metformin, a medication known for its anti-glycemic properties, also demonstrates potent immune system activation. In our study, using a 4T1 breast cancer model in BALB/C WT mice, we examined metformin's impact on the functional phenotype of multiple immune cells, with a specific emphasis on natural killer T (NKT) cells due to their understudied role in this context. Metformin administration delayed the appearance and growth of carcinoma. Furthermore, metformin increased the percentage of IFN-γ+ NKT cells, and enhanced CD107a expression, as measured by MFI, while decreasing PD-1+, FoxP3+, and IL-10+ NKT cells in spleens of metformin-treated mice. In primary tumors, metformin increased the percentage of NKp46+ NKT cells and increased FasL expression, while lowering the percentages of FoxP3+, PD-1+, and IL-10-producing NKT cells and KLRG1 expression. Activation markers increased, and immunosuppressive markers declined in T cells from both the spleen and tumors. Furthermore, metformin decreased IL-10+ and FoxP3+ Tregs, along with Gr-1+ myeloid-derived suppressor cells (MDSCs) in spleens, and in tumor tissue, it decreased IL-10+ and FoxP3+ Tregs, Gr-1+, NF-κB+, and iNOS+ MDSCs, and iNOS+ dendritic cells (DCs), while increasing the DCs quantity. Additionally, increased expression levels of MIP1a, STAT4, and NFAT in splenocytes were found. These comprehensive findings illustrate metformin's broad immunomodulatory impact across a variety of immune cells, including stimulating NKT cells and T cells, while inhibiting Tregs and MDSCs. This dynamic modulation may potentiate its use in cancer immunotherapy, highlighting its potential to modulate the tumor microenvironment across a spectrum of immune cell types.

Investigating the Link between STAT4 Genetic Variants, STAT4 Protein Concentrations, and Laryngeal Squamous Cell Carcinoma: A Comprehensive Analysis of Clinical Manifestations.

According to recent research, inflammatory STAT4 and its protein impact may be important factors in developing cancerous diseases. Still unanalyzed is this effect in patients with laryngeal squamous cell carcinoma (LSCC). In the present study, we evaluated four single nucleotide variants (SNVs) of STAT4 (rs10181656, rs7574865, rs7601754, and rs10168266) and STAT4 serum levels to determine their link between LSCC development and its clinical manifestations. A total of 632 men (324 LSCC patients and 338 healthy individuals) were involved in this study. The genotyping was carried out using real-time PCR. Additionally, we measured 80 study subjects' (40 LSCC patients and 40 control subjects) STAT4 protein concentrations using an enzyme-linked immunosorbent assay (ELISA). In our study, the T allele of STAT4 rs7574865 significantly increases the likelihood of LSCC occurrence by 1.4-fold. Additionally, this SNV is associated with higher odds of early-stage disease, T1 size LSCC development, absence of metastasis to neck lymph nodes, and well-differentiated carcinoma. The G allele of rs10181656 is significantly associated with various clinical characteristics of LSCC, increasing the odds of early- and advanced-stage disease by 2.8-fold and 1.9-fold, respectively. Additionally, this allele is linked to an increased likelihood of developing tumors of different sizes and non-metastasized LSCC, as well as poorly differentiated carcinoma, highlighting its potential impact on the development and features of LSCC. Conclusion: The analysis of the STAT4 rs7574865 SNV revealed that the G allele is linked to a more favorable prognosis in LSCC. Additionally, it is hypothesized that the G allele of rs10181656 may be associated with the occurrence of LSCC but may not serve as a sensitive prognostic biomarker for distinguishing between disease stages, cell differentiation, or tumor size.

STAT4 activation by leukemia inhibitory factor confers a therapeutic effect on intestinal inflammation.

T helper 17 (Th17)-cell differentiation triggered by interleukin-6 (IL-6) via STAT3 activation promotes inflammation in inflammatory bowel disease (IBD) patients. However, leukemia inhibitory factor (LIF), an IL-6 family cytokine, restricts inflammation by blocking Th17-cell differentiation via an unknown mechanism. Here, we report that microbiota dysregulation promotes LIF secretion by intestinal epithelial cells (IECs) in a mouse colitis model. LIF greatly activates STAT4 phosphorylation on multiple SPXX elements within the C-terminal transcription regulation domain. STAT4 and STAT3 act reciprocally on both canonical cis-inducible elements (SIEs) and noncanonical "AGG" elements at different loci. In lamina propria lymphocytes (LPLs), STAT4 activation by LIF blocks STAT3-dependent Il17a/Il17f promoter activation, whereas in IECs, LIF bypasses the extraordinarily low level of STAT4 to induce YAP gene expression via STAT3 activation. In addition, we found that the administration of LIF is sufficient to restore microbiome homeostasis. Thus, LIF effectively inhibits Th17 accumulation and promotes repair of damaged intestinal epithelium in inflamed colon, serves as a potential therapy for IBD.

SDMA attenuates renal tubulointerstitial fibrosis through inhibition of STAT4.

BACKGROUND: Renal tubulointerstitial fibrosis is the hallmark of various chronic kidney diseases. Symmetric dimethylarginine (SDMA) is an independent cardiovascular risk factor in patients with chronic kidney diseases, which is mostly excreted through renal tubules. However, the effect of SDMA on kidneys in a pathological condition is currently unknown. In this study, we investigated the role of SDMA in renal tubulointerstitial fibrosis and explored its underlying mechanisms. METHODS: Mouse unilateral ureteral obstruction (UUO) and unilateral ischemia-reperfusion injury (UIRI) models were established to study renal tubulointerstitial fibrosis. SDMA was injected into kidneys through ureter retrogradely. TGF-ß stimulated human renal epithelial (HK2) cells were used as an in vitro model and treated with SDMA. Signal transducer and activator of transcription-4 (STAT4) was inhibited by berbamine dihydrochloride or siRNA or overexpressed by plasmids in vitro. Masson staining and Western blotting were performed to evaluate renal fibrosis. Quantitative PCR was performed to validate findings derived from RNA sequencing analysis. RESULTS: We observed that SDMA (from 0.01 to 10 µM) dose-dependently inhibited the expression of pro-fibrotic markers in TGF-ß stimulated HK2 cells. Intrarenal administration of SDMA (2.5 µmol/kg or 25 µmol/kg) dose-dependently attenuated renal fibrosis in UUO kidneys. A significant increase in SDMA concentration (from 19.5 to 117.7 nmol/g, p < 0.001) in mouse kidneys was observed after renal injection which was assessed by LC-MS/MS. We further showed that intrarenal administration of SDMA attenuated renal fibrosis in UIRI induced mouse fibrotic kidneys. Through RNA sequencing analysis, we found that the expression of STAT4 was reduced by SDMA in UUO kidneys, which was further confirmed by quantitative PCR and Western blotting analysis in mouse fibrotic kidneys and renal cells. Inhibition of STAT4 by berbamine dihydrochloride (0.3 mg/ml or 3.3 mg/ml) or siRNA reduced the expression of pro-fibrotic markers in TGF-ß stimulated HK2 cells. Furthermore, blockage of STAT4 attenuated the anti-fibrotic effect of SDMA in TGF-ß stimulated HK2 cells. Conversely, overexpression of STAT4 reversed the anti-fibrotic effect of SDMA in TGF-ß stimulated HK2 cells. CONCLUSION: Taken together, our study indicates that renal SDMA ameliorates renal tubulointerstitial fibrosis through inhibition of STAT4.

SNP in PTPN22, PADI4, and STAT4 but Not TRAF1 and CD40 Increase the Risk of Rheumatoid Arthritis in Polish Population.

Single nucleotide polymorphisms in non-HLA genes are involved in the development of rheumatoid arthritis (RA). SNPS in genes: PADI4 (rs2240340), STAT4 (rs7574865), CD40 (rs4810485), PTPN22 (rs2476601), and TRAF1 (rs3761847) have been described as risk factors for the development of autoimmune diseases, including RA. This study aimed to assess the prevalence of polymorphisms of these genes in the Polish population of patients with rheumatoid arthritis as compared to healthy controls. 324 subjects were included in the study: 153 healthy subjects and 181 patients from the Department of Rheumatology, Medical University of Lodz who fulfilled the criteria of rheumatoid arthritis diagnosis. Genotypes were determined by Taqman SNP Genotyping Assay. rs2476601 (G/A, OR = 2.16, CI = 1.27-3.66; A/A, OR = 10.35, CI = 1.27-84.21), rs2240340 (C/T, OR = 4.35, CI = 2.55-7.42; T/T, OR = 2.80, CI = 1.43-4.10) and rs7574865 (G/T, OR = 1.97, CI = 1.21-3.21; T/T, OR = 3.33, CI = 1.01-11.02) were associated with RA in the Polish population. Rs4810485 was also associated with RA, however after Bonferroni's correction was statistically insignificant. We also found an association between minor alleles of rs2476601, rs2240340, and rs7574865 and RA (OR = 2.32, CI = 1.47-3.66; OR = 2.335, CI = 1.64-3.31; OR = 1.88, CI = 1.27-2.79, respectively). Multilocus analysis revealed an association between CGGGT and rare (below 0.02 frequency) haplotypes (OR = 12.28, CI = 2.65-56.91; OR = 3.23, CI = 1.63-6.39). In the Polish population, polymorphisms of the PADI4, PTPN22, and STAT4 genes have been detected, which are also known risk factors for RA in various other populations.

[Predictive significance of genetic analysis of the development of dry eye disease of different origin]. / Prediktivnaya znachimost' geneticheskogo analiza razvitiya sindroma «sukhogo glaza¼ razlichnogo geneza.

One of the etiological causes of dry eye disease (DED) is systemic autoimmune diseases (AID): primary Sjögren's syndrome (PSS), rheumatoid arthritis (RA); their manifestation may begin with ophthalmic symptoms. The relationship of PSS and RA with genetic factors is proven. The contribution of polymorphic markers of the genes THBS1, MUC1, TRIM21, STAT4, PTPN22 in the development of these diseases is established, as well as their connection with the development of DED. A panel of genetic markers for evaluating the risk of developing DED in PSS and RA is developed, and its sensitivity and specificity is determined. PURPOSE: The aim of the study was to determine the prognostic significance of a panel of polymorphic gene markers in the development of dry eye syndrome in patients with primary Sjögren's syndrome and rheumatoid arthritis over a five-year follow-up period. MATERIAL AND METHODS: Patients with a verified diagnosis of PSS and RA without signs of DED were examined (n=35 and n=42, respectively). The control group included 82 volunteers without AID and DED. The observation period was 5 years. Every year all study subjects underwent an ophthalmological clinical and functional examination. RESULTS: Dry eye disease had developed in groups of patients with AID with predisposing genotypes of polymorphic markers of the genes THBS1, MUC1, TRIM21, STAT4, PTPN22. The peak of DED development in these patients was in the third year of the follow-up. As a result of ROC analysis, it was found that the sensitivity and specificity of determining the predisposing genotypes of polymorphic markers of the THBS1, MUC1, TRIM21, STAT4, PTPN22 genes was 68 and 87%, respectively (p<0.0001). CONCLUSION: Genetic research methods are essential for minimally invasive early diagnosis of dry eye disease, and can subsequently become the basis for a personalized approach to its treatment.

Promoted CD4+ T cell-derived IFN-γ/IL-10 by photobiomodulation therapy modulates neurogenesis to ameliorate cognitive deficits in APP/PS1 and 3xTg-AD mice.

BACKGROUND: The immune system has been implicated in synaptic plasticity, inflammation, and the progression of Alzheimer's disease (AD). However, there were few studies on improving the niche microenvironment of neural stem cells (NSCs) in the brain of AD to promote adult hippocampal neurogenesis (AHN) by regulating the function of non-parenchymal immune cells. METHODS: The lymph nodes of amyloid precursor protein/presenilin 1 (APP/PS1) and 3xTg (APP/PS1/tau) mouse models of AD were treated with photobiomodulation therapy (PBMT) for 10 J/cm2 per day for 1 month (10 min for each day), T lymphocytes isolated from these two AD models were treated with PBMT for 2 J/cm2 (5 min for each time). The NSCs isolated from hippocampus of these two AD models at E14, and the cells were co-cultivated with PBMT-treated T lymphocyte conditioned medium for NSCs differentiation. RESULTS: Our results showed that PBMT treatment could promote AHN and reverse cognitive deficits in AD mouse model. The expression of interferon-γ (IFN-γ) and interleukin-10 (IL-10) was upregulated in the brain of these two AD models after PBMT treated, which was induced by the activation of Janus kinase 2 (JAK2)-mediated signal transducer and activator of transcription 4 (STAT4)/STAT5 signaling pathway in CD4+ T cells. In addition, elevated CD4+ T cell levels and upregulated transforming growth factor-ß1 (TGFß1)/insulin-like growth factors-1 (IGF-1)/brain-derived neurotrophic factor (BDNF) protein expression levels were also detected in the brain. More importantly, co-cultivated the PBMT-treated T lymphocyte conditioned medium with NSCs derived from these two AD models was shown to promote NSCs differentiation, which was reflected in the upregulation of both neuronal class-III ß-tubulin (Tuj1) and postsynaptic density protein 95 (PSD95), but the effects of PBMT was blocked by reactive oxygen species (ROS) scavenger or JAK2 inhibitor. CONCLUSION: Our research suggests that PBMT exerts a beneficial neurogenesis modulatory effect through activating the JAK2/STAT4/STAT5 signaling pathway to promote the expression of IFN-γ/IL-10 in non-parenchymal CD4+ T cells, induction of improvement of brain microenvironmental conditions and alleviation of cognitive deficits in APP/PS1 and 3xTg-AD mouse models.

The effects of the interactions of STAT4 rs7574865 with HBV mutations on the risk of hepatocellular carcinoma.

Signal transducer and activator of transcription 4 (STAT4) is closely related to liver diseases and affects the processes of inflammation and carcinogenesis by regulating immune responses. A single-nucleotide polymorphism rs7574865 (T > G) in STAT4 has been reported to be associated with the risk of hepatocellular carcinoma (HCC). In addition, hepatitis B virus (HBV) mutations are crucial risk factors for HBV-induced HCC. However, the effects of the interactions of STAT4 rs7574865 with HBV mutations on the risk of HCC remain unknown. Rs7574865 was genotyped in 846 healthy controls (HCs), 968 chronic hepatitis B (CHB) subjects, 316 liver cirrhosis (LC) subjects and 1021 HCC subjects using Sequenom MassArray. HBV mutations were detected via direct sequencing. Multivariate logistic regression analysis was used to evaluate the effects of the interactions of STAT4 rs7574865 with HBV mutations on the risk of HCC. We found that the rs7574865 TT genotype was significantly associated with HBeAg seroconversion (TT vs. GG, p = 0.012; TT vs. GT, p = 0.033). The rs7574865 GG genotype was significantly associated with increased risks of CHB (p = 0.048), LC (p = 0.005) and HCC (p < 0.001). The interaction term between rs7574865 and HBV C1913A significantly increased the risk of progression from CHB to HCC (p = 0.038), while the interaction term between rs7574865 and HBV T1674C significantly increased the risk of progression from LC to HCC (p = 0.023). STAT4 rs7574865 is significantly associated with the risks of CHB, LC and HCC. The interactions of rs7574865 with HBV C1913A and T1674C mutations significantly increase the risk of HCC, which have the potential to identify HBV-infected individuals who tend to progress from CHB or LC to HCC.

STAT4 genetic polymorphism significantly affected HBeAg seroconversion in HBeAg-positive chronic hepatitis B patients receiving Peginterferon-α therapy: A prospective cohort study in China.

A variant in signal transducer and activator of transcription 4 (STAT4) was reported to correlate with the response of interferon-α (IFN-α) in a retrospective study in hepatitis B e antigen (HBeAg)-positive chronic hepatitis B virus (CHB) patients. Here, we conducted a prospective study to analyze the effect of STAT4 genetic polymorphism on the response of pegylated interferon-α-2a (PegIFN-α-2a) in HBeAg-positive patients. A prospective, multicenter, open-label, parallel cohort study was performed. One hundred and fifty treatment-naïve and 156 nucleos(t)ide analog (NA)-experienced HBeAg-positive CHB patients were enrolled, respectively. All patients received PegIFN-α-2a treatment for 48 weeks and 24-week follow-up post PegIFN-α-2a treatment. Before treatment, STAT4 genetic polymorphism was determined by PCR and DNA sequencing. Serological markers, serum HBV DNA levels, and adverse events were collected at each visit. We observed a larger reduction of HBV DNA load and a significantly higher HBeAg seroconversion rate in the GT/TT group than in the GG group at week 72 (p = 0.002 and p = 0.023) in treatment-naïve patients. In NA-experienced patients, the HBeAg seroconversion rate in the GT/TT group was higher than that in the GG group at week 72 (p = 0.005). STAT4 rs7574865 gene polymorphism was the strongest independent predictor of HBeAg seroconversion in both paralleled cohorts. Also, patients in the GT/TT group had a higher hepatitis B surface antigen loss rate than in the GG group in the study. There was no significant difference in adverse events between GG and GT/TT groups. This prospective cohort study confirmed that STAT4 rs7574865 gene polymorphism is associated with HBeAg seroconversion and HBsAg loss irrespective of naïve and NA-experienced HBeAg-positive CHB patients treated with PegIFN-α-2a.

MiR-363-5p modulates regulatory T cells through STAT4-HSPB1-Notch1 axis and is associated with the immunological abnormality in Graves' disease.

MiRNAs are a class of small non-coding RNAs with ability to regulate function of Treg cells and are involved in many autoimmune diseases. Our previous study found that miR-363-5p expression was significantly upregulated in peripheral Treg cells of GD patients. Herein, we aimed to investigate its effect and mechanism on Treg cell dysfunction in GD patients. The results showed that miR-363-5p upregulation was significantly associated with the Treg cell dysfunction and inflammatory factors levels in GD patients. Transcriptome sequencing revealed that 883 genes were significantly regulated by miR-363-5p in Treg cells. These genes with significant differential expression were primarily involved in lymphocyte differentiation, immunity, as well as Notch1 and various interleukin signalling pathways. Moreover, miR-363-5p can regulate HSPB1 and Notch1 through the target gene STAT4, thereby regulating Notch1 signalling pathway and inhibiting Treg cells. The effects of miR-363-5p on Treg cell function and STAT4-HSPB1-Notch1 axis were also verified in GD patients. In conclusion, our results indicated that miR-363 could inhibit the proliferation, differentiation and function of Treg cells by regulating the STAT4-HSPB1-Notch1 axis through target gene STAT4. MiR-363-5p may play an important role in Treg cell dysfunction and immune tolerance abnormalities in GD patients.

The IL-12-STAT4 axis in the pathogenesis of human systemic lupus erythematosus.

Generation of autoantibodies is a hallmark of systemic lupus erythematosus (SLE). As demonstrated in a number of lupus mouse models, recent evidence suggests that both GC and extrafollicular pathways contribute to the generation of autoantibodies also in human SLE, and that CD11c+ IgD- CD27- (double negative:DN) B cells play a central role in the latter pathway. In this mini-review, the author will first briefly summarize the features of CD11c+ DN B cells in human SLE, and discuss how the IL-12-STAT4 axis might contribute to the generation of autoantibodies in SLE. In addition, various types of CD4+ helper T cell subsets promoting the generation of autoantibodies in SLE will be described, and finally it will be discussed how these recent discoveries contribute to understanding of SLE pathogenesis and treatment of SLE patients.

Overexpression of E3 ubiquitin ligase Cbl attenuates endothelial dysfunction in diabetes mellitus by inhibiting the JAK2/STAT4 signaling and Runx3-mediated H3K4me3.

BACKGROUND: Diabetes mellitus (DM), a most common chronic disease, is featured with impaired endothelial function and bioavailability of nitric oxide (NO), while E3 ubiquitin ligase appears to alleviate endothelial dysfunction as a promising option for DM treatment. Herein, we aimed to determine whether E3 ubiquitin ligase casitas B-lineage lymphoma (Cbl) alleviates endothelial dysfunction in DM rats by JAK2/STAT4 pathway. METHODS: A rat model of DM was developed through intraperitoneal injection of streptozotocin, followed by collection of aortic tissues to determine the expression of Cbl, JAK2, runt-related transcription factor 3 (Runx3) and STAT4. Human umbilical vein endothelial cells (HUVECs) were cultured in high glucose (HG) condition to induce DM as an in vitro model. With gain- and loss-function method, we assessed the aberrantly expressed Cb1 on endothelial dysfunction, NO production and apoptosis of HUVECs. RESULTS: Cbl was reduced in DM rat tissues and HG-induced HUVECs, where JAK2, Runx3 and STAT4 were elevated. It was found that overexpression of Cbl alleviated endothelial dysfunction by increasing NO production and restoring vasodilation and suppressing apoptosis of HUVECs. Mechanistically, Cb1 enhanced JAK2 ubiquitination and decreased JAK2 and STAT4 expression, where STAT4 improved Runx3 expression by regulating histone H3 lysine 4 trimethylation level. Overexpression of JAK2 and STAT4, or Runx3 increased apoptosis of HUVECs, abrogating the effect of Cb1 on endothelial function. CONCLUSION: In conclusion, Cbl alleviates endothelial dysfunction by inactivation of the JAK2/STAT4 pathway and inhibition of Runx3 expression in DM. These evidence might underlie novel Cbl-based treatment against DM in the future.