STAT4 Mediates IL-6 Trans-Signaling Arrhythmias in High Fat Diet Guinea Pig Heart.

Obesity is a major risk factor for the development of life-threatening malignant ventricular tachyarrhythmias (VT) and sudden cardiac death (SCD). Risks may be highest for patients with high levels of the proinflammatory cytokine interleukin (IL)-6. We used our guinea pig model of high-fat diet (HFD)-induced arrhythmias that exhibit a heightened proinflammatory-like pathology, which is also observed in human obesity arrhythmias, as well as immunofluorescence and confocal microscopy approaches to evaluate the pathological IL-6 trans-signaling function and explore the underlying mechanisms. Using blind-stick and electrocardiogram (ECG) techniques, we tested the hypothesis that heightened IL-6 trans-signaling would exhibit increased ventricular arrhythmia/SCD incidence and underlying arrhythmia substrates. Remarkably, compared to low-fat diet (LFD)-fed controls, HFD promoted phosphorylation of the IL-6 signal transducer and activator of transcription 4 (STAT4), leading to its activation and enhanced nuclear translocation of pSTAT4/STAT4 compared to LFD controls and pSTAT3/STAT3 nuclear expression. Overactivation of IL-6 trans-signaling in guinea pigs prolonged the QT interval, which resulted in greater susceptibility to arrhythmias/SCD with isoproterenol challenge, as also observed with the downstream Janus kinase (JAK) 2 activator. These findings may have potentially profound implications for more effective arrhythmia therapy in the vulnerable obese patient population.

Association between STAT4 gene polymorphism and susceptibility to pulmonary tuberculosis in the Moldavian population.

Signal transducer and activator of transcription 4 (STAT4) plays a crucial role in the host immune response against Mycobacterium tuberculosis. This study investigates the association between STAT4 gene polymorphisms and pulmonary tuberculosis (TB) risk in the Moldavian population. A total of 272 TB patients and 251 community-matched controls underwent screening for functional single-nucleotide polymorphisms (SNPs) rs897200 and rs7574865 in the STAT4 gene. The minor T allele and the TT/CT genotype of rs897200 demonstrated a significant association with reduced pulmonary TB risk (allelic model: adjusted OR = .74, p = .025; log-additive model: adjusted OR = .72, p = .02; and dominant model: adjusted OR = .65, p = .023), indicating a protective effect. Similar associations, characterized by an even more pronounced reduction in risk, were observed among females and late-onset TB patients (>44 years). No significant associations were found for rs7574865. In addition, a combined genotype analysis incorporating 43 SNPs from our previous studies revealed potential associations, such as STAT4 rs897200 CT with IFNG rs2430561 AA (adjusted OR = .36, p = .0025) and STAT4 rs897200 CT with TNFA rs1800629 GA (adjusted OR = .33, p = .0012). This study emphasizes the significant association of STAT4 rs897200 with pulmonary TB risk in the Moldavian population, underscoring its role in the disease development.

Interferon pathway lupus risk alleles modulate risk of death from acute COVID-19.

Type I interferon (IFN) is critical in our defense against viral infections. Increased type I IFN pathway activation is a genetic risk factor for systemic lupus erythematosus (SLE), and a number of common risk alleles contribute to the high IFN trait. We hypothesized that these common gain-of-function IFN pathway alleles may be associated with protection from mortality in acute COVID-19. We studied patients admitted with acute COVID-19 (756 European-American and 398 African-American ancestry). Ancestral backgrounds were analyzed separately, and mortality after acute COVID-19 was the primary outcome. In European-American ancestry, we found that a haplotype of interferon regulatory factor 5 (IRF5) and alleles of protein kinase cGMP-dependent 1 (PRKG1) were associated with mortality from COVID-19. Interestingly, these were much stronger risk factors in younger patients (OR = 29.2 for PRKG1 in ages 45-54). Variants in the IRF7 and IRF8 genes were associated with mortality from COVID-19 in African-American subjects, and these genetic effects were more pronounced in older subjects. Combining genetic information with blood biomarker data such as C-reactive protein, troponin, and D-dimer resulted in significantly improved predictive capacity, and in both ancestral backgrounds the risk genotypes were most relevant in those with positive biomarkers (OR for death between 14 and 111 in high risk genetic/biomarker groups). This study confirms the critical role of the IFN pathway in defense against COVID-19 and viral infections, and supports the idea that some common SLE risk alleles exert protective effects in antiviral immunity.

Assessing the association of rs7574865 STAT4 gene variant and type 1 diabetes mellitus among Egyptian patients.

BACKGROUND: Variants in the signal transducer and activator of transcription 4 (STAT4) gene have an important role in the incident of multiple autoimmune diseases including type 1 diabetes mellitus (T1D). It is a genetically related auto-immune disorder that resulted from T cell-mediated destruction of pancreatic cells that are in control for the production of insulin in the blood. The current study aimed to clarify the role of STAT4 (rs7574865) variant allelic and genotypic variations in the susceptibility to type 1 diabetes among Egyptians by using the real-time PCR. RESULTS: A total of 100 patients and 100 controls were genotyped for rs7574865, and the biochemical and anthropometric parameters were measured to show that type 1 diabetic patients had significantly higher levels of HbA1c and triglycerides compared to non-diabetic individuals (P < 0.05). And genetically, the T allele and GT genotype have a significant correlation with diabetes type 1. CONCLUSION: It was confirmed by this study that the rs7574865 T allele and GT genotype have a significant correlation with diabetes type 1 incidence among Egyptian patients.

Genetic variants in STAT4 and their interactions with environmental factors for the incidence of hepatocellular carcinoma.

BACKGROUND: A recent genome-wide association study (GWAS) has posed STAT4 as a promising susceptibility gene for hepatocellular carcinoma (HCC). However, the most significant variant in this GWAS, rs7574865, yielded inconsistent results. OBJECTIVE: This study, in a Southern Chinese population, was aimed to clarify the roles in HCC incidence of the rs7574865 and other two potentially functional variants, rs897200 and rs1031507 in STAT4. METHODS: This study enrolled 631 new HCC cases and 631 cancer-free controls. The genetic association was estimated using the multivariate logistic regression model. The pairwise gene-environment interactions were assessed using the multiplicative term in regression model and the "Delta" method for the additive scale. RESULTS: In the multivariate analysis, the rs7574865 TT genotype conferred a decreased risk of HCC compared to the GG genotype (adjusted OR = 0.62, 95%CI = 0.38∼0.99). The significant association of rs7574865 was also observed under the additive genetic model, with an adjusted OR of 0.81 (95%CI = 0.65∼0.99). Nevertheless, other two variants alone showed no significant association, as well as the haplotypes and genetic risk scores. Further analysis indicated a potential interaction between the rs897200 and alcohol drinking (P= 0.048 and 0.072 for additive and multiplicative interactions, respectively). Drinkers with the rs897200 CT+CC genotypes presented an increased disease-risk, as compared with non-drinkers carrying the TT genotype (adjusted OR = 1.68, 95%CI = 1.11∼2.54). CONCLUSIONS: The variant in STAT4, rs7574865, serves as a potential marker for predicting incidence of HCC. The rs897200 variant possibly interplays with alcohol drinking to alter HCC risk in the Southern Chinese, but warrants further investigation.

Computationally predicted SARS-COV-2 encoded microRNAs target NFKB, JAK/STAT and TGFB signaling pathways.

Recently an outbreak that emerged in Wuhan, China in December 2019, spread to the whole world in a short time and killed >1,410,000 people. It was determined that a new type of beta coronavirus called severe acute respiratory disease coronavirus type 2 (SARS-CoV-2) was causative agent of this outbreak and the disease caused by the virus was named as coronavirus disease 19 (COVID19). Despite the information obtained from the viral genome structure, many aspects of the virus-host interactions during infection is still unknown. In this study we aimed to identify SARS-CoV-2 encoded microRNAs and their cellular targets. We applied a computational method to predict miRNAs encoded by SARS-CoV-2 along with their putative targets in humans. Targets of predicted miRNAs were clustered into groups based on their biological processes, molecular function, and cellular compartments using GO and PANTHER. By using KEGG pathway enrichment analysis top pathways were identified. Finally, we have constructed an integrative pathway network analysis with target genes. We identified 40 SARS-CoV-2 miRNAs and their regulated targets. Our analysis showed that targeted genes including NFKB1, NFKBIE, JAK1-2, STAT3-4, STAT5B, STAT6, SOCS1-6, IL2, IL8, IL10, IL17, TGFBR1-2, SMAD2-4, HDAC1-6 and JARID1A-C, JARID2 play important roles in NFKB, JAK/STAT and TGFB signaling pathways as well as cells' epigenetic regulation pathways. Our results may help to understand virus-host interaction and the role of viral miRNAs during SARS-CoV-2 infection. As there is no current drug and effective treatment available for COVID19, it may also help to develop new treatment strategies.

Association of STAT4 Gene Rs7574865, Rs10168266 Polymorphisms and Systemic Lupus Erythematosus Susceptibility: A Meta-analysis.

Association of signal transducer and activator of transcription 4 (STAT4) gene rs7574865, rs10168266 polymorphisms with systemic lupus erythematosus (SLE) risk remains unclear. A meta-analysis was conducted on the correlation between rs7574865, rs10168266 polymorphisms and SLE. Twenty-six studies were recruited in our study (17,389 patients and 29,273 controls). For rs7574865, results showed significant associations between T allele and SLE susceptibility in overall population, Asians and Europeans (OR=1.557, 95%CI: 1.505-1.611, P<0.001; OR=1.557, 95%CI: 1.498-1.661, P<0.001; OR=1.548, 95%CI: 1.474-1.625, P<0.001). Significant associations of genotypes TT, GT, TT+TG and SLE risk were observed in general subjects, Asians and Europeans (all P<0.001). Regarding rs10168266, increased T allele frequencies were detected in overall SLE cases and those from Asian origin (OR=1.532, 95%CI: 1.440-1.631, P<0.001; OR=1.575, 95%CI: 1.445-1.717, P<0.001). The overall data showed that TT genotype, CT genotype and TT+CT genotype were significantly correlated with SLE (all P < 0.001). In conclusion, the present study verified strong association of STAT4 gene rs7574865, rs10168266 polymorphisms and SLE susceptibility.

Silencing of STAT4 Protects Against Autoimmune Myocarditis by Regulating Th1/Th2 Immune Response via Inactivation of the NF-κB Pathway in Rats.

Signal transducer and activator of transcription 4 (STAT4) has been implicated in the progression of myocarditis. The aim of the current study was to investigate the role by which STAT4 influences autoimmune myocarditis in an attempt to identify a theoretical therapeutic perspective for the condition. After successful establishment of an autoimmune myocarditis rat model, the expression patterns of STAT4, NF-κB pathway-related genes, Th1 inflammatory cytokines (IFN-γ and IL-2), and Th2 inflammatory cytokines (IL-6 and IL-10) were subsequently determined. The rats with autoimmune myocarditis were treated with oe-STAT4 or sh-STAT4 lentiviral vectors to evaluate the role of STAT4 in autoimmune myocarditis, or administrated with 1 mL 10 µmol/L of BAY11-7082 (the NF-κB pathway inhibitor) via tail vein to investigate the effect of the NF-κB pathway on autoimmune myocarditis. Finally, cell apoptosis was evaluated. The serum levels of IFN-γ and IL-2, extent of IκBα and P65 phosphorylation, and the expression of STAT4 were elevated, while the serum levels of IL-6 and IL-10 as well as the expression of IκBα were reduced among the rats with autoimmune myocarditis, which was accompanied by an increase in the apoptotic cells. More importantly, the silencing of STAT4 or the inhibition of the NF-κB pathway was detected to result in a decrease in the serum levels of IFN-γ and IL-2 and an elevation of the serum levels of IL-6 and IL-10, and inhibited myocardial cell apoptosis in rats with autoimmune myocarditis. Moreover, STAT4 silencing was also observed to decrease the extent of IκBα and P65 phosphorylation while acting to elevate the expression of IκBα. Taken together, silencing of STAT4 could hinder the progression of autoimmune myocarditis by balancing the expression of Th1/Th2 inflammatory cytokines via the NF-κB pathway, which may provide a novel target for experimental autoimmune myocarditis (EAM) treatment.

Association between STAT4 polymorphisms and risk of primary biliary cholangitis: a meta-analysis.

Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease. Several studies reported that SATA4 (signal transducer and activator of transcription 4) polymorphisms were significantly associated with PBC susceptibility. In order to derive a more comprehensive estimation of the association between STAT4 and PBC risk, this meta-analysis was conducted. Thirteen eligible studies from 8 articles with a total number of 11,310 cases and 27,844 controls were included in this meta-analysis. Pooled odds ratios (OR) and 95% confidence intervals (CI) were estimated with fixed effects model or random effects model. The results showed statistically significant association between polymorphisms of rs7574865, rs3024921, rs6752770, rs7601754 and rs10168266 in STAT4 and PBC risk under the allelic effect model (rs7574865, T vs. G, OR = 1.24, 95% CI 1.14-1.35; rs3024921, T vs. A, OR = 1.65, 95% CI 1.44-1.91; rs6752770, G vs. A, OR = 1.24, 95% CI 1.11-1.39; rs7601754, A vs. G, OR = 1.35, 95% CI 1.17-1.55; and rs10168266, T vs. C, OR = 1.31, 95% CI 1.22-1.41). Furthermore, the rs7574865 polymorphism was significantly associated with PBC risk under all genotype genetic models (dominant effect model: TT + TG vs. GG, OR = 1.43, 95% CI 1.19-1.71; recessive effect: TT vs. TG + GG, OR = 1.40, 95% CI 1.24-1.58; and co-dominant effect: TT vs. GG, OR = 1.67, 95% CI 1.37-2.02). The sensitivity analysis by omitting one study at a time showed that the results were stable. No publication bias was indicated from both Begg's test and Egger's weighted regression. This meta-analysis suggested that polymorphisms of rs7574865, rs3024921, rs6752770, rs7601754 and rs10168266 in STAT4 were significantly associated with the risk of PBC.

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.

Association of Polymorphisms of Signal Transducer and Activator of Transcription 4 with the Susceptibility to Preeclampsia / 中山大学学报(医学科学版)

[Objective]To investigate associations between the functional polymorphisms of signal transducer and activator of transcription 4 (STAT4) gene and preeclampsia.[Methods]PCR-restriction fragment length polymorphism was used to genotype rs10181656 and rs16833431 local polymorphism in 228 preeclampsia cases and 179 normal controls.[Results](1)The frequencies of rs10181656C/G were 35.96%,46.37%in genotype C/C,47.81%,44.69%in genotype C/G and 16.23%,8.94%in genotype G/G between preeclampsia patients and normal controls. They reached statistical difference (P = 0.031). There was different distribution in two alleles(C and G)between preeclampsia patients and normal controls(P=0.009).(2)There was no different distribution in 3 genotypes(C/C,C/T,T/T)and 2 alleles(C and T)of rs16833431 C/T between preeclampsia patients and normal controls(P =0.508,0.461).[Conclusions]Functional polymorphisms of the rs10181656 locus could associate with the preeclampsia. The polymor-phisms of the rs16833431 locus could not associate with the preeclampsia.

Association of rs10181656 Polymorphism in Signal Transducer and Activator of Transcription 4 Gene with Susceptibility to Unexplained Recurrent Spontaneous Abortion / 中山大学学报(医学科学版)

[Objective] To investigate associations between the functional polymorphisms of signal transducer and activator of transcription 4 (STAT4) gene and unexplained recurrent spontaneous abortion (URSA) and between STAT4 protein expression and the genotypes of rs 10181656 locus.[Methods] PCR-restriction fragment length polymorphism was used to genotype rs 1 0181656 locus polymorphism in 332 URSA cases and 260 normal controls,in 86 URSA cases and 77 normal controls of which immunohistochemical technique was used to detect STAT4 protein expression.[Results] The frequencies of rs10181656 C/G were 36.45 ％,46.54％ in genotype C/C,46.99％,45.38％ in genotype C/G and 16.57％,8.08％ in genotype G/G between URSA patients and normal controls.They reached statistical difference (P ＜ 0.05).The carriers of rs 10181656 G allele increased the risk of URSA (OR =1.50,P ＜ 0.05).STAT4 protein expression in decidual tissues:①There was statistical difference in the STAT4 protein expression in decidual tissues between cases and controls (P ＜ 0.05).In URSA patients there was statistical difference in the STAT4 protein expression among genotype CC,CG and GG of rs10181656 locus (P ＜ 0.05).So was in normal controls (P ＜ 0.05).In genotype CC there was no difference in the STAT4 protein expression between cases and controls (P ＞ 0.05).Neither was In genotype CG and GG respectively (P all ＞ 0.05).[Conclusion] Functional polymorphisms of the rs10181656 locus could probably associate with the susceptibility of URSA via STAT4 protein expression increased by genotype G/G in maternal decidual tissue.

Cryptotanshinone inhibits lung tumor growth by increasing CD4+ T cell cytotoxicity through activation of the JAK2/STAT4 pathway.

Cryptotanshinone is one of the fat-soluble phenanthrene quinone components. In vitro studies have shown that tanshinone compounds can inhibit the proliferation of various tumor cells and affect cell cycle distribution. The aim of the present study was to better understand the effect of cryptotanshinone on the inhibition of small cell lung cancer by cytotoxic cluster of differentiation (CD)4+ T cells through activation of the Janus kinase 2/signal transducer and activator of transcription 4 (JAK2/STAT4) pathway. The Cell Counting kit-8 assay and the lactate dehydrogenase assay were used to analyze the cell proliferation of H446 and CD4+ T cells, and the cell cytotoxicity of CD4+ and CD8+ T cells, respectively. JAK2 and STAT4 protein expression was measured by western blot analysis. Cryptotanshinone effectively inhibited the tumor growth of the H446 cells and the cell proliferation of the CD4+ T cells. Treatment with cryptotanshinone increased the cytotoxicity of the CD4+ T cells, but could not affect the cytotoxicity of the CD8+ T cells. Meanwhile, cryptotanshinone induced phosphorylated (p)-JAK2 and p-STAT4 protein expression in the CD4+ T cells. These results suggest that cryptotanshinone inhibits the cell growth of lung tumors by increasing CD4+ T cell toxicity through activation of the JAK2/STAT4 pathway.

Association of genetic polymorphisms of STAT4, the cytotoxic T-lymphocyte antigen-4 and chromosome 9p21.3 with susceptibility to rheumatoid arthritis in Minnan population / 中华风湿病学杂志

Objective A very high prevalence of rheumatoid arthritis (RA) is observed in Minnan population in China.We aimed to explore the genetic characteristics of RA in Minnan population and genetic mechanisms of RA by studying the associations of three single nucleotide polymorphisms (SNPs) of signal transducer and activator of transcription 4 (STAT-4) (rs7574865),the cytotoxic T-lymphocyte antigen-4 (CTLA)-4 (rs3087243) and chromosome 9p21.3(rs1333049) with RA in Minnan population.Methods A case-control study of 119 RA patients and 125 normal controls from Quanzhou were enrolled.SNPs (rs7574865,rs3087243,rs1333049) were genotyped by allele-specific polymerase chain reaction (PCR) and analyzed by SPSS 18.0.x2-test was applied to compare allele and genotype frequeneies betweeen cases and controlsLogistic regression models were used to analyze the SNPs.Results The results showed the genotype distributions of STAT4 genes were significantly different between case and control groups (P＜0.01).Compared with the GT heterozygous genotype,TT and GG homozygosity carriers had a lower risk (OR=0498 and 0.300,P=0.018 and P=0.002 respectively).There was not statistical difference in genotypes and allele in CTLA-4 (rs3087243) between RA patients and healthy controls (x2=4.083,P=0.130),but compared with the AG genotyoe,GG homozygosity carriers had a lower risk on basis of statistics (OR=0.580,P=0.04).There was not statistical difference in genotypes and allele in the chromosome 9p21.3 (rs1333049) (P＞0.05),but compared with the GG genotype carriers,CC and GC genotypes carriers had a lower risk on basis of statistics (OR=0.565,P=0.0495).Conclusion Chromosome 9p21.3 (rs1333049) and CTLA-4 rs3087243 G/A may not be associated with susceptibility to RA in Minnan popula-tions.This replication study confirmes that STAT4 rs7574865 G/T polymorphism is associated with susceptibility to RA in Minnan population.

STAT4 rs7574865 polymorphism contributes to the risk of type 1 diabetes: a meta analysis.

The signal transducer and activator of transcription 4 (STAT4) rs7574865 polymorphism has been indicated to be correlated with type 1 diabetes (T1D) susceptibility, but study results are still debatable. Thus, a meta-analysis was conducted. The electronic databases PubMed, Embase, CNKI, and Web of Science (ISI) were searched to find eligible studies. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. A significant association was found between STAT4 rs7574865 polymorphism and T1D risk (OR=1.30; 95% CI, 1.13-1.48; P<0.01; I(2) =73%). Significant associations were also found in Asians (OR=1.33; 95% CI, 1.04-1.71; P=0.02; I(2) =60%) and Caucasians (OR=1.26; 95% CI, 1.08-1.47; P<0.01; I(2) =74%), respectively. This association was also positive in the pediatric patients (OR=1.41; 95% CI, 1.19-1.68; P<0.01; I(2) =46%). Moreover, we found that STAT4 rs7574865 polymorphism was associated with early-onset T1D risk (OR=1.43; 95% CI, 1.16-1.77; P<0.01; I(2) =0%). This meta-analysis suggested that the STAT4 rs7574865 polymorphism may be associated with T1D development.

Porphyromonas gingivalis RagB is a proinflammatory signal transducer and activator of transcription 4 agonist.

Periodontal diseases are semi-ubiquitous and caused by chronic, plaque-induced inflammation. The 55-kDa immunodominant RagB outer membrane protein of Porphyromonas gingivalis, a keystone periodontal pathogen, has been proposed to facilitate nutrient transport. However, potential interactions between RagB and the innate response have not been examined. We determined that RagB exposure led to the differential and dose-related expression of multiple genes encoding proinflammatory mediators [interleukin-1α (IL-1α), IL-1ß, IL-6, IL-8 and CCL2; all P < 0.05] in primary human monocytes and to the secretion of tumor necrosis factor and IL-8, but not interferon-γ or IL-12. RagB was shown to be a Toll-like receptor 2 (TLR2) and TLR4 agonist that activated signal transducer and activator of transcription 4 and nuclear factor-κB signaling, as determined by a combination of blocking antibodies, pharmaceutical inhibitors and gene silencing. In keeping, a ΔragB mutant similarly exhibited reduced inflammatory capacity, which was rescued by ragB complementation. These results suggest that RagB elicits a major pro-inflammatory response in primary human monocytes and, therefore, could play an important role in the etiology of periodontitis and systemic sequelae.

Calcitonin gene-related peptide inhibits human immunodeficiency type 1 transmission by Langerhans cells via an autocrine/paracrine feedback mechanism.

AIM: Peripheral neurones innervating mucosal epithelia are in direct contact with resident immune cells, including Langerhans cells (LCs). Such neurones secrete the neuropeptide calcitonin gene-related peptide (CGRP) that modulates LCs function. We recently found that CGRP strongly inhibits human immunodeficiency virus type 1 (HIV-1) transmission, by interfering with multiple steps of mucosal LC-mediated HIV-1 transfer, including increased expression of the LC-specific lectin langerin. Herein, we investigated the anti-HIV-1 mechanism of CGRP. METHODS: In the presence of CGRP, HIV-1 transfer from LCs to CD4+ T cells was tested with viral clones using either the HIV-1 co-receptor CCR5 (R5) or CXCR4 (X4). Surface expression of CCR5, CXCR4 and langerin was evaluated by flow cytometry. CGRP secretion by LCs was measured with an enzyme immunoassay. Expression of the multimeric CGRP receptor was examined by quantitative real-time RT-PCR and immuno-fluorescent microscopy. RESULTS: Calcitonin gene-related peptide decreased transfer of HIV-1 R5, but increased that of X4. These opposing effects correlated with decreased CCR5 vs. increased CXCR4 surface expression in LCs. Inhibition of HIV-1 R5 transfer by CGRP involved signal transducer and activator of transcription 4 (STAT4) activation. Both αCGRP and ßCGRP were similarly efficient in decreasing HIV-1 R5 transfer and increasing langerin expression. LCs secreted low basal levels of endogenous CGRP, which increased markedly following CGRP treatment. CGRP also increased expression of its cognate receptor in LCs. CONCLUSION: CGRP engages a positive feedback mechanism that would further enhance its anti-HIV-1 activity. This information might be relevant for the therapeutic use of CGRP as a prophylactic agent against HIV-1.

Contribution of the STAT4 rs7574865 gene polymorphism to the susceptibility to autoimmune thyroiditis in healthy Turk population and psoriatic subgroups.

INTRODUCTION: STAT4 is an important transcription factor that activates gene transcription as a response to cytokines. Recently, the influence of STAT4 gene on autoimmune disease has been widely studied in many different immune-related diseases. Autoimmune, metabolic and cardiovascular disorders are more common in psoriatic patients. STAT4 may be a unique gene that switches on in autoimmune-related thyroid disease in psoriatic patients. THE AIM OF THE STUDY: To explore the association of a STAT4 rs7574865 polymorphism to autoimmune thyroid diseases in the general Turkish population and psoriatic subgroups. MATERIAL AND METHODS: A total of 132 psoriatic patients and 118 non-psoriatic volunteers were genotyped for STAT4 rs7574865 using real time PCR. Twenty-four of the psoriatic patients and 15 of the non-psoriatic volunteers have autoimmune-related thyroid diseases. RESULTS: The prevalence of the T allele [OR = 4.37; 95% CI: 1.05-19; p = 0.03] of the STAT4 rs7574865 was higher in individuals with autoimmune-related thyroid diseases among the all non-psoriatic volunteers. The volunteers with autoimmune-related thyroid diseases has an increased allele positivity and carriers having at least one of the risk allele was significantly higher than in counterparts with a GG wild genotype [ORGT/TT vs. GG: 1.73; 95% CI: 0.09-32; p = 0.03]. Yet, there was no evidence of an association between rs7574865 and autoimmune-related thyroid disease in psoriatic patients. CONCLUSIONS: The STAT4 rs7574865 polymorphism increases autoimmune-related thyroid disease susceptibility among the general population but not in psoriatic patients.

Fibroblast signal transducer and activator of transcription 4 drives cigarette smoke-induced airway fibrosis.

Cigarette smoke-induced emphysema and small airway remodeling are the anatomic bases of chronic obstructive pulmonary disease (COPD), but the pathogenesis of these changes is unclear, and current treatments for COPD are minimally effective. To evaluate the role of signal transducer and activator of transcription (STAT)-4 in cigarette smoke-induced small airway remodeling, we used C57BL/6J (wild type [WT]) and STAT4-/- mice exposed to air or cigarette smoke for 6 months and isolated airway and parenchymal fibroblasts. We also compared the results with those obtained with human fibroblasts. We found that STAT4-/- mice were protected against smoke-induced small airway remodeling but not emphysema. STAT4 is abundantly expressed in airway compared with parenchymal-derived fibroblasts isolated from normal human and murine lung. WT airway fibroblasts proliferate faster than STAT4-/- airway fibroblasts, whereas there is no difference between strains for parenchymal fibroblasts. IL-12 is up-regulated in the lung after smoke exposure, and IL-12 receptor B2 is expressed on airway and parenchymal fibroblasts in mouse and human lung. Treatment with IL-12 causes phosphorylation of STAT4 in WT airway fibroblasts. Exposure of WT airway, but not parenchymal, fibroblasts to IL-12 causes increased expression of collagen 1α1 and transforming growth factor ß1, factors involved in small airway remodeling, whereas STAT4-/- fibroblasts are unresponsive to IL-12. These results indicate that IL-12 can drive small airway remodeling via STAT4 signaling and suggest that treatment with clinically available anti-IL-12p40 drugs might provide a new approach to preventing small airway remodeling in cigarette smokers.

STAT4 deficiency protects against neointima formation following arterial injury in mice.

Signal transducer and activator of transcription 4 (STAT4) has been associated with susceptibility to autoimmune diseases. Intriguingly, we previously reported that STAT4 might play a critical role in vascular smooth muscle cell (VSMC) proliferation. The present study therefore investigated the impact of STAT4 on VSMC migration, apoptosis and neointimal hyperplasia postinjury, as well as the underlying mechanisms. Guide-wire injury was associated with development of intimal neointima, STAT4 and phosphorylated STAT4 (p-STAT4) expressions were apparently up-regulated in the injured arteries. Neointima was greatly blocked in STAT4 knockout (KO) mice compared with wild type (WT) mice. A marked loss of inflammatory cells was identified in the vasculature postinjury in STAT4 KO mice. VSMC apoptosis was enhanced in the vasculature postinjury in STAT4 KO mice compared with WT mice. Cultured primary STAT4 KO VSMCs displayed reduced migration in comparison with WT controls. Mechanically, the deletion of STAT4 potently decreased the level of MCP-1, and its downstream targets MMP1 and MMP2. The effect of STAT4 on VSMC apoptosis was mainly mediated by the activation of the mitochondrial apoptotic pathway, as manifested by increased cytochrome c release and the activation of caspase-3. STAT4 therefore represents a promising molecular target to limit restenosis after artery intervention.