SOCS3 promotor hypermethylation and STAT3-NF-κB interaction downregulate SOCS3 expression in human coronary artery smooth muscle cells

Role of the suppressor of cytokine signaling-3 in the pathogenesis of Graves' orbitopathy

Objective

Graves' orbitopathy (GO) is characterized by increased production of proinflammatory cytokines and hyaluronic acid by fibroblasts and their differentiation into adipocytes in response to immunologic stimuli. The suppressor of cytokine signaling-3 (SOCS3) is an inducible negative regulator of the JAK/STAT pathway, implicated in various inflammatory diseases. In this study, we investigated the role of SOCS3 in the inflammatory and adipogenic pathogenesis of GO.

Methods

Transcriptome profiling of orbital tissues obtained from five patients with GO who underwent orbital decompression surgery and four healthy subjects was performed using RNA-sequencing. Among the top-ranked differentially expressed genes, we identified 24 hub genes and found SOCS3 to be the most significantly upregulated gene in GO samples compared with that in healthy tissue based on quantitative real-time polymerase chain reaction. SOCS3 expression was analyzed in IL-1β-, and IGF-1-stimulated orbital fibroblasts using quantitative real-time polymerase chain reaction and western blot analysis. Knockdown of SOCS3 using siRNA transfection was performed to assess the effect of SOCS3 on the production of proinflammatory cytokines and adipogenic phenotype.

Results

We identified 184 consistently differentially expressed genes-120 upregulated and 64 downregulated- in GO tissues compared to the control. SOCS3 mRNA expression was significantly higher in GO tissues (n = 17) compared with that in control (n = 15). IL-1β and IGF-1 enhanced the expression of SOCS3 at mRNA and protein levels. Silencing of SOCS3 suppressed the levels of IL-1β-induced proinflammatory cytokines, including IL-6, IL-8, and ICAM-1. Phosphorylation of NF-kB and Akt was suppressed and adipogenic differentiation was significantly attenuated by SOCS3 knockdown.

Conclusions

SOCS3 was remarkably expressed in the adipose tissues of patients with GO and was induced by IL-1β and IGF-1 in orbital fibroblasts. SOCS3 inhibition attenuated the production of proinflammatory cytokines and adipogenesis, suggesting that SOCS3 may be a therapeutic target for controlling the inflammatory and adipogenic mechanisms in GO.

The Exacerbating Effects of the Tumor Necrosis Factor in Cardiovascular Stenosis: Intimal Hyperplasia

TNF-α functions as a master regulator of inflammation, and it plays a prominent role in several immunological diseases. By promoting important cellular mechanisms, such as cell proliferation, migration, and phenotype switch, TNF-α induces its exacerbating effects, which are the underlying cause of many proliferative diseases such as cancer and cardiovascular disease. TNF-α primarily alters the immune component of the disease, which subsequently affects normal functioning of the cells. Monoclonal antibodies and synthetic drugs that can target TNF-α and impair its effects have been developed and are currently used in the treatment of a few select human diseases. Vascular restenosis is a proliferative disorder that is initiated by immunological mechanisms. In this review, the role of TNF-α in exacerbating restenosis resulting from neointimal hyperplasia, as well as molecular mechanisms and cellular processes affected or induced by TNF-α, are discussed. As TNF-α-targeting drugs are currently not approved for the treatment of restenosis, the summation of the topics discussed here is anticipated to provide information that can emphasize on the use of TNF-α-targeting drug candidates to prevent vascular restenosis.

Endogenous blocking of TLR2 along with TNF-α and IL-1β ameliorates the severity of the S. aureus arthritis via modulating STAT3/SOCS3 expressions in tissue resident macrophages

In vivo studies identifying a role of TLR2 in septic arthritis models are lacking. TNF-α played as the most important proinflammatory cytokine, and connected directly to the pathogenesis of bacterial arthritis. IL-1β is another central mediator cytokine in arthritis. It is therefore reasonable to question the role of neutralization of endogenous TNF-α and IL-1β along with TLR2 and associated downstream signaling as crucial mediators in the S. aureus -induced inflammatory arthritis. In reaction to an injury or a pathogen encounter, innate immune cells serve as the initial line of defense. TLR2 mediated entry of S. aureus into macrophage cells initiates an array of inflammatory cascades. After macrophage cell gets activated at the site inflammation, they generate elevated number of cytokines which includes TNF-α, IL-1β. This cytokines signals through STAT1/STAT3 mediated pathways. Thus, aim of this study was to discover how This bone damage could be altered by altering the STAT/STAT3/SOCS3 ratio by blocking TLR2, a particular S. aureus binding site, in conjunction with the use of IL-1 and TNF- antibodies for neutralizing endogenous IL-1β and TNF-α. Additionally, the role of local macrophages in therapy of arthritis was investigated in synovial and Splenic tissue. To comprehend the inflammatory milieu within the system, ROS and other antioxidant enzymes, along with the expression of mTOR in macrophage cells, were also taken into consideration. The detrimental impact of bacterial burden on synovial joints was reduced by simultaneously inhibiting TLR2, TNF-α, and IL-1β. Lowered IFN-γ decreases its sensitivity to STAT1 and lowered IL-6 reduces STAT3 expressions. Whereas, elevated IL-10 enhances SOSC3 expression, which thereby able to limits STAT1/STAT3 inter-conversion. As a result, NF-κB activity was downregulated.

Increased Expression of Long Noncoding RNA LOC100506314 in T cells from Patients with Nonsegmental Vitiligo and Its Contribution to Vitiligo Pathogenesis

This study aimed to identify the abnormal expression of long noncoding RNAs (lncRNAs) in T cells from patients with vitiligo and to investigate their functional roles in the immune system. Using microarray analysis, the expression levels of RNA transcripts in T cells from patients with vitiligo and controls were compared. We identified several genes and validated their expression levels in T cells from 41 vitiligo patients and 41 controls. The biological functions of the lncRNAs were studied in a transfection study using an RNA pull-down assay, followed by proteomic analysis and western blotting. The expression levels of 134 genes were significantly increased, and those of 142 genes were significantly decreased in T cells from vitiligo patients. After validation, six genes had increased expression, and three genes had decreased expression in T cells from patients with vitiligo. T-cell expression of LOC100506314 was increased in vitiligo, especially CD4+, but not CD8+ T cells. The expression levels of LOC100506314 in CD4+ T cells was positively and significantly associated with the severity of vitiligo. LOC100506314 was bound to the signal transducer and activator of transcription 3 (STAT3) and macrophage migration inhibitory factor (MIF). Enhanced expression of LOC100506314 inhibited the phosphorylation of STAT3, protein kinase B (AKT), and extracellular signal-regulated protein kinases (ERK), as well as the levels of nuclear protein of p65 and the expression of IL-6 and IL-17 in Jurkat cells and T cells from patients with vitiligo. In conclusion, this study showed that the expression of LOC100506314 was elevated in CD4+ T cells from patients with vitiligo and associated the severity of vitiligo. LOC100506314 interacted with STAT3 and MIF and inhibited IL-6 and IL-17 expression by suppressing the STAT3, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), AKT, and ERK pathways. Enhanced expression of LOC100506314 in T cells may be a potential treatment strategy for vitiligo.

DNA methylation at the suppressor of cytokine signaling 3 (SOCS3) gene influences height in childhood

Human height is strongly influenced by genetics but the contribution of modifiable epigenetic factors is under-explored, particularly in low and middle-income countries (LMIC). We investigate links between blood DNA methylation and child height in four LMIC cohorts (n = 1927) and identify a robust association at three CpGs in the suppressor of cytokine signaling 3 (SOCS3) gene which replicates in a high-income country cohort (n = 879). SOCS3 methylation (SOCS3m)-height associations are independent of genetic effects. Mendelian randomization analysis confirms a causal effect of SOCS3m on height. In longitudinal analysis, SOCS3m explains a maximum 9.5% of height variance in mid-childhood while the variance explained by height polygenic risk score increases from birth to 21 years. Children's SOCS3m is associated with prenatal maternal folate and socio-economic status. In-vitro characterization confirms a regulatory effect of SOCS3m on gene expression. Our findings suggest epigenetic modifications may play an important role in driving child height in LMIC.

Aronia melanocarpa Anthocyanin Extracts Improve Hepatic Structure and Function in High-Fat Diet-/Streptozotocin-Induced T2DM Mice

Anthocyanins can prevent and ameliorate type 2 diabetes mellitus (T2DM), but its mechanism of action has not been fully established. IKK/NF-κB and JAK/Stat pathways have multiple effects, triggering T2DM. Liver abnormalities in individuals with T2DM are detrimental to glycemic control. We determined whether anthocyanins could improve the liver of individuals with T2DM using IKK/NF-κB and JAK/Stat. We established a T2DM mouse model using a high-fat diet and streptozotocin and then performed Aronia melanocarpa anthocyanin extracts' (AMAEs') administration for 5 weeks. AMAEs improved blood glucose and hyperinsulinemia of T2DM mice. In the liver of AMAE-administered T2DM mice, ROS, IKKβ/NF-κB p65, and JAK2/Stat3/5B signalings were down-regulated, thereby reducing the suppressor of cytokine signaling 3 (SOCS3), iNOS, and inflammatory mediators. AMAE-improved hyperinsulinemia also down-regulated SOCS3 by decreasing p-Stat5B in hepatocytes. AMAEs enhanced glucose uptake and conversion and decreased hepatocyte enlargement and inflammatory cells in the liver of T2DM mice. These indicated that AMAEs could alleviate oxidative stress, insulin resistance, inflammation, and tissue damage in the liver of T2DM mice through inhibiting NF-κB p65 and Stat3/5B.

Short communication: TNF-α and IGF-1 regulates epigenetic mechanisms of HDAC2 and HDAC10

Vascular restenosis often presents as a consequence of injury to the vessel wall, resulting from stenting and other interventional procedures. Such injury to the arteries induces proliferation of Vascular Smooth Muscle Cells (VSMCs), resulting in cellular hyperplasia and restenosis. We and others have previously reported de-novo production of different cytokines and growth factors such as Tumor Necrosis Factor Alpha (TNF-α) and Insulin like Growth Factor 1 (IGF-1), after vascular injury. As complex as it is, the profuse proliferation of VSMCs appears to be occurring due to several induced factors which initiate molecular mechanisms and exacerbate disease conditions. In many pathological events, the deleterious effects of TNF-α and IGF-1 in initiating disease mechanisms was reported. In the present work, we explored whether TNF-α and IGF-1 can regulate epigenetic mechanisms that promote proliferation of VSMCs. We investigated the mechanistic roles of proteins which can structurally interact with DNMT1 and initiate cellular pathways that promote proliferation of VSMCs. Our findings here, identify a novel molecular mechanism that is initiated by TNF-α and IGF-1. It was previously reported that DNMT1 expression is directly induced by TNF-α and IGF-1 treatment and increased/induced expression of DNMT1 causes silencing of genes that are essential to maintaining cellular homeostasis such as the tumor suppressor genes. We have earlier reported that TNF-α and IGF-1 treatment elevates DNMT1 expression in VSMCs and causes increased VSMC proliferation. However, the molecular mechanisms involved were not fully deciphered. Interestingly, in the present study we found that TNF-α and IGF-1 treatment failed to elevate DNMT1 expression levels in absence of HDAC2 and HDAC10. Also, while HDAC2 expression was not affected by HDAC10 knockdown, HDAC2 is essentially required for HDAC10 expression. Further, in TNF-α and IGF-1 induced epigenetic signaling mechanism, the expression of two important proteins EZH2 and PCNA seem to be regulated in an HDAC2-HDAC10 dependent manner. Our results show an inter-dependence of epigenetic mediators in inducing proliferation in VSMCs. To our knowledge, this is the first report that shows HDAC2 dependent expression of HDAC10, and suggests a novel mechanistic link between DNMT1, HDAC10 and HDAC2 that regulates EZH2 and PCNA to enhance cell proliferation of VSMCs which is the underlying cause for neointimal hyperplasia and restenosis.

The JAK/STAT signaling pathway: from bench to clinic

The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway was discovered more than a quarter-century ago. As a fulcrum of many vital cellular processes, the JAK/STAT pathway constitutes a rapid membrane-to-nucleus signaling module and induces the expression of various critical mediators of cancer and inflammation. Growing evidence suggests that dysregulation of the JAK/STAT pathway is associated with various cancers and autoimmune diseases. In this review, we discuss the current knowledge about the composition, activation, and regulation of the JAK/STAT pathway. Moreover, we highlight the role of the JAK/STAT pathway and its inhibitors in various diseases.

The JAK/STAT signaling pathway: from bench to clinic

The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway was discovered more than a quarter-century ago. As a fulcrum of many vital cellular processes, the JAK/STAT pathway constitutes a rapid membrane-to-nucleus signaling module and induces the expression of various critical mediators of cancer and inflammation. Growing evidence suggests that dysregulation of the JAK/STAT pathway is associated with various cancers and autoimmune diseases. In this review, we discuss the current knowledge about the composition, activation, and regulation of the JAK/STAT pathway. Moreover, we highlight the role of the JAK/STAT pathway and its inhibitors in various diseases.

Association between SOCS3 hypermethylation and HBV-related hepatocellular carcinoma and effect of sex and age: A meta-analysis

BACKGROUND

Suppressor 3 of cytokine signaling (SOCS3) hypermethylation has been reported to participate in hepatocellular carcinoma (HCC) development and progression, but conflicting results were published. This study aimed to analyze the clinical effects of SOCS3 hypermethylation in HCC and the effects of sex and age on SOCS3 hypermethylation in HCC.

METHODS

Databases were searched for relevant case-control and cohort studies on SOCS3 hypermethylation in HBV-related HCC. In vitro and in vivo studies and studies of patients with serious comorbidities were excluded. Review Manager 5.2 was used to estimate the effects of the results among the selected studies. Forest plots, sensitivity analysis, and bias analysis for the included studies were also conducted.

RESULTS

Finally, 8 relevant studies met the inclusion criteria. A significant difference in SOCS3 hypermethylation in HCC was found between tumor and nontumor groups (the odds ratio [OR] = 2.01, 95% confidence interval [CI]: 1.48-2.73, P < .00001; P for heterogeneity = .39, I2 = 5%). The meta-analysis suggested no significant difference in the effect of sex (OR = 1.00, 95% CI: 0.76-1.31, P = .76; P for heterogeneity = .44, I2 = 0%) and age on SOCS3 hypermethylation in HCC (OR = 1.11, 100% CI: 0.78-1.29, P = .03; P for heterogeneity = .14, I2 = 36%). Limited publication bias was observed in this study.

CONCLUSION

SOCS3 hypermethylation is associated with HBV-related HCC. Sex and age do not affect the association between SOCS3 hypermethylation and HCC. SOCS3 might be a treatment target for HCC.

Interleukin 27 as an inducer of antiviral response against chikungunya virus infection in human macrophages

Chikungunya virus (CHIKV) is known to have a wide range of tropism in human cell types throughout infection, including keratinocytes, fibroblasts, endothelial cells, monocytes, and macrophages. We reported that human monocytes-derived macrophages (MDMs) are permissive to CHIKV infection in vitro. We found that the peak of CHIKV replication was at 24 hpi; however, at 48 hpi, a significant reduction in viral titer was observed that correlated with high expression levels of genes encoding antiviral proteins (AVPs) in an IFN-independent manner. To explore the molecular mechanisms involved in the induction of antiviral response in CHIKV-infected MDMs, we performed transcriptomic analysis by RNA-sequencing. Differential expression of genes at 24 hpi showed that CHIKV infection abrogated the expression of all types of IFNs in MDMs. However, we observed that CHIKV-infected MDMs activated the JAK-STAT signaling and induced a robust antiviral response associated with control of CHIKV replication. We identified that the IL27 pathway is activated in CHIKV-infected MDMs and that kinetics of IL27p28 mRNA expression and IL27 protein production correlated with the expression of AVPs in CHIKV-infected MDMs. Furthermore, we showed that stimulation of THP-1-derived macrophages with recombinant-human IL27 induced the activation of the JAK-STAT signaling and induced a robust pro-inflammatory and antiviral response, comparable to CHIKV-infected MDMs. Furthermore, pre-treatment of MDMs with recombinant-human IL27 inhibits CHIKV replication in a dose-dependently manner (IC50 = 1.83 ng/mL). Altogether, results show that IL27 is highly expressed in CHIKV-infected MDMs, leading to activation of JAK-STAT signaling and stimulation of pro-inflammatory and antiviral response to control CHIKV replication in an IFN-independent manner.

Comprehensive analysis of suppressor of cytokine signaling proteins in human breast Cancer

Background

Abnormal expression of suppressor of cytokine signaling (SOCS) proteins regulates tumor angiogenesis and development in cancers. In this study, we aimed to perform a comprehensive bioinformatic analysis of SOCS proteins in breast invasive carcinoma (BRCA).

Methods

The gene expression, methylation level, copy number, protein expression and patient survival data related to SOCS family members in BRCA patients were obtained from the following databases: Oncomine, The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), Human Protein Atlas (HPA), Gene Expression Profiling Interactive Analysis (GEPIA), PCViz, cBioPortal and Kaplan-Meier plotter. Correlation analyses, identification of interacting genes and construction of regulatory networks were performed by functional and pathway enrichment analyses, weighted gene coexpression network analysis (WGCNA) and gene set enrichment analysis (GSEA).

Results

Data related to 1109 BRCA tissues and 113 normal breast tissue samples were extracted from the TCGA database. SOCS2 and SOCS3 exhibited significantly lower mRNA expression levels in BRCA tissues than in normal tissues. BRCA patients with high mRNA levels of SOCS3 (p < 0.01) and SOCS4 (p < 0.05) were predicted to have significantly longer overall survival (OS) times. Multivariate analysis showed that SOCS3 was an independent prognostic factor for OS. High mRNA expression levels of SOCS2 (p < 0.001), SOCS3 (p < 0.001), and SOCS4 (p < 0.01), and a low expression level of SOCS5 (p < 0.001) were predicted to be significantly associated with better recurrence-free survival (RFS). Multivariate analysis showed that SOCS2 was an independent prognostic factor for RFS. Lower expression levels of SOCS2 and SOCS3 were observed in patients with tumors of more advanced clinical stage (p < 0.05). Functional and pathway enrichment analyses, together with WGCNA and GSEA, showed that SOCS3 and its interacting genes were significantly involved in the JAK-STAT signaling pathway, suggesting that JAK-STAT signaling might play a critical role in BRCA angiogenesis and development. Western blot results showed that overexpression of SOCS3 inhibited the activity of the JAK-STAT signaling pathway in vitro.

Conclusions

SOCS family proteins play a very important role in BRCA. SOCS3 may be a prognostic factor and SOCS2 may be a potential therapeutic target in breast cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08434-y.

Essential roles of insulin and IGF-1 receptors during embryonic lineage development

The insulin and insulin-like growth factor-1 (IGF-1) receptors are important for the growth and development of embryonic tissues. To directly define their roles in the maintenance of pluripotency and differentiation of stem cells, we knocked out both receptors in induced pluripotent stem cells (iPSCs). iPSCs lacking both insulin and IGF-1 receptors (double knockout, DKO) exhibited preserved pluripotency potential despite decreased expression of transcription factors Lin28a and Tbx3 compared to control iPSCs. While embryoid body and teratoma assays revealed an intact ability of DKO iPSCs to form all three germ layers, the latter were composed of primitive neuroectodermal tumor-like cells in the DKO group. RNA-seq analyses of control vs DKO iPSCs revealed differential regulation of pluripotency, developmental, E2F1, and apoptosis pathways. Signaling analyses pointed to downregulation of the AKT/mTOR pathway and upregulation of the STAT3 pathway in DKO iPSCs in the basal state and following stimulation with insulin/IGF-1. Directed differentiation toward the three lineages was dysregulated in DKO iPSCs, with significant downregulation of key markers (Cebpα, Fas, Pparγ, and Fsp27) in adipocytes and transcription factors (Ngn3, Isl1, Pax6, and Neurod1) in pancreatic endocrine progenitors. Furthermore, differentiated pancreatic endocrine progenitor cells from DKO iPSCs showed increased apoptosis. We conclude that insulin and insulin-like growth factor-1 receptors are indispensable for normal lineage development and perturbations in the function and signaling of these receptors leads to upregulation of alternative compensatory pathways to maintain pluripotency.

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Insulin and IGF-1 receptor signaling regulate the expression of pluripotency genes Lin28 and Tbx3.

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The STAT3 pathway is upregulated in DKO iPSCs.

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RNA-seq analyses revealed key developmental and apoptosis pathways regulated by insulin and IGF-1 receptors.

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Lineage development was dysregulated in DKO iPSCs with downregulation of key mesoderm and endodermal markers.

Genetic information from discordant sibling pairs points to ESRP2 as a candidate trans-acting regulator of the CF modifier gene SCNN1B

SCNN1B encodes the beta subunit of the epithelial sodium channel ENaC. Previously, we reported an association between SNP markers of SCNN1B gene and disease severity in cystic fibrosis-affected sibling pairs. We hypothesized that factors interacting with the SCNN1B genomic sequence are responsible for intrapair discordance. Concordant and discordant pairs differed at six SCNN1B markers (Praw = 0.0075, Pcorr = 0.0397 corrected for multiple testing). To identify the factors binding to these six SCNN1B SNPs, we performed an electrophoretic mobility shift assay and captured the DNA-protein complexes. Based on protein mass spectrometry data, the epithelial splicing regulatory protein ESRP2 was identified when using SCNN1B-derived probes and the ESRP2-SCNN1B interaction was independently confirmed by coimmunoprecipitation assays. We observed an alternative SCNN1B transcript and demonstrated in 16HBE14o- cells that levels of this transcript are decreased upon ESRP2 silencing by siRNA. Furthermore, we confirmed that mildly and severely affected siblings have different ESPR2 genetic backgrounds and that ESRP2 markers are linked to the response of CF patients' nasal epithelium to amiloride, indicating ENaC involvement (Pbest = 0.0131, Pcorr = 0.068 for multiple testing). Our findings demonstrate that sibling pairs clinically discordant for CF can be used to identify meaningful DNA regulatory elements and interacting factors.

Tumor Necrosis Factor α Influences Phenotypic Plasticity and Promotes Epigenetic Changes in Human Basal Forebrain Cholinergic Neuroblasts

TNFα is the main proinflammatory cytokine implicated in the pathogenesis of neurodegenerative disorders, but it also modulates physiological functions in both the developing and adult brain. In this study, we investigated a potential direct role of TNFα in determining phenotypic changes of a recently established cellular model of human basal forebrain cholinergic neuroblasts isolated from the nucleus basalis of Meynert (hfNBMs). Exposing hfNBMs to TNFα reduced the expression of immature markers, such as nestin and β-tubulin III, and inhibited primary cilium formation. On the contrary, TNFα increased the expression of TNFα receptor TNFR2 and the mature neuron marker MAP2, also promoting neurite elongation. Moreover, TNFα affected nerve growth factor receptor expression. We also found that TNFα induced the expression of DNA-methylation enzymes and, accordingly, downregulated genes involved in neuronal development through epigenetic mechanisms, as demonstrated by methylome analysis. In summary, TNFα showed a dual role on hfNBMs phenotypic plasticity, exerting a negative influence on neurogenesis despite a positive effect on differentiation, through mechanisms that remain to be elucidated. Our results help to clarify the complexity of TNFα effects in human neurons and suggest that manipulation of TNFα signaling could provide a potential therapeutic approach against neurodegenerative disorders.

Potential Molecular Mechanism of the NPPB Gene in Postischemic Heart Failure with and without T2DM

Background

This study is aimed at investigating natriuretic peptide B (NPPB) coexpression genes and their pathways involved in heart failure (HF) among patients both with and without type 2 diabetes mellitus (T2DM).

Methods

The microarray dataset GSE26887, containing 19 postischemic HF patients' peripheral blood samples (7 with T2DM and 12 without T2DM), was examined to detect the genes coexpressed with NPPB using the corr.test function in the R packet. Furthermore, using online analytical tools, we determined the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, Gene Ontology (GO) annotation, and protein-protein interaction (PPI) network of the coexpression genes. The modules and hub genes of the PPI network were then identified using the Cytoscape software.

Results

In patients with T2DM, a total of 41 biological processes (BP), 20 cellular components (CC), 13 molecular functions (MF), and 41 pathways were identified. Furthermore, a total of 61 BPs, 16 CCs, 13 MFs, and 22 pathways in patients without T2DM were identified. In both groups of patients, 17 BPs, 10 CCs, 6 MFs, and 13 pathways were enriched. We also identified 173 intersectional coexpression genes (63 positively, 106 negatively, and 4 differently coexpressed in patients with and without T2DM, respectively) in both types of patients, which were enriched in 16 BPs, 8 CCs, 3 MFs, and 8 KEGG pathways. Moreover, the PPI network (containing 237 edges and 170 nodes) with the top module significantly enriched in 4 BPs (tricarboxylic acid metabolic process, citrate metabolic process, tricarboxylic acid cycle, and aerobic respiration) and 3 pathways (citrate cycle, malaria parasite metabolic pathway, and AGE-RAGE signaling pathway in diabetic complications) was constructed. DECR1, BGN, TIMP1, VCAN, and CTCF are the top hub genes.

Conclusions

Our findings may elucidate the functions and roles of the NPPB gene in patients with postischemic HF and facilitate HF management.

25-Hydroxyvitamin D3 positively regulates periodontal inflammaging via SOCS3/STAT signaling in diabetic mice

BACKGROUND

Diabetes is a known age-related disease. Inflammaging has recently been shown to result in diabetic complications. Vitamin D₃ is related to aging in the latest study but little is known about the underlying mechanism. Here, we investigated the effects of 25-Hydroxyvitamin D₃ (25(OH)D₃) on inflammaging in diabetic periodontitis, a common chronic inflammatory diabetic complication.

EXPERIMENTAL DESIGN

A model of Porphyromonas gingivalis-infected db/db mice as experimental type 2 diabetic periodontitis was adopted in the whole study. A range of techniques, including microCT, western blotting, ELISA, histological and immunohistochemical analysis, were carried out in this study. The distinctive senescence-associated secretory phenotype (SASP) in serum was measured by Luminex technology.

RESULTS

We found an archetypal inflammaging status occurred in db/db mice. An increased SASP, senescent enhancement, and periodontal destruction were observed in periodontitis-db/db mice. Upon administration with 25(OH)D₃, periodontitis-db/db mice presented increased levels of serum 25(OH)D₃, 1α,25-Dihydroxyvitamin D₃ and calcium. Moreover, decreased p16/p21-positive cells, relieved periodontal conditions and ameliorated serum SASP secretion were found in the periodontitis-db/db mice after treatment. Gingival tissue exhibited increased level of VDR and decreased expression of SOCS3, p-STAT3/STAT3, p-STAT5/STAT5, NF-κB and IL-1β, which were consistent with the change of p16/p21 expression.

CONCLUSION

Diabetic periodontitis appeared to develop an inflammaging status resulted in periodontal infection. 25(OH)D₃ could inhibit SASP secretion through reducing SOCS3 expression in experimental diabetic periodontitis, dependently inactivating NF-κB pro-inflammatory signaling. The reversible effect further documented that the inflammaging might be a highly likely contributor in diabetic periodontitis.

The long non-coding RNA DANCR regulates the inflammatory phenotype of breast cancer cells and promotes breast cancer progression via EZH2-dependent suppression of SOCS3 transcription

Long non-coding RNA (lncRNA) is involved in the regulation of tumorigenesis and metastasis. In this study, we focused on the clinical relevance, biological effects, and molecular mechanisms of the lncRNA differentiation antagonizing non-protein coding RNA (DANCR) in breast cancer. We compared the expression of DANCR between breast cancer and normal tissues, and between breast cancer cell lines and normal breast epithelial cells using quantitative real-time PCR (qRT-PCR) analysis. By knocking down and overexpressing DANCR, we assessed its significance in regulating viability (MTT assay), migration/invasion (Transwell assay), epithelial-mesenchymal transition (western blot), stemness (mammosphere formation assay and western blot), and production of inflammatory cytokines (qRT-PCR and ELISA) of breast cancer cells in vitro, as well as xenograft growth in vivo. Furthermore, using ChIP and RNA immunoprecipitation, we examined the reciprocal regulation between DANCR and suppressor of cytokine signaling 3 (SOCS3) in breast cancer. DANCR was significantly up-regulated in tissue samples from patients with breast cancer, as well as in breast cancer cell lines, as compared with normal tissues and breast epithelial cells, respectively. The highest DANCR expression levels were associated with advanced tumor grades or lymph node metastasis. DANCR was necessary and sufficient to control multiple malignant phenotypes of breast cancer cells in vitro and xenograft growth in vivo. Mechanistically, DANCR promoted the binding of enhancer of zeste homolog 2 (EZH2) to the promoter of SOCS3, thereby epigenetically inhibiting SOCS3 expression. Functionally, SOCS3 up-regulation or EZH2 inhibition could rescue multiple malignant phenotypes induced by DANCR. Our data indicate that DANCR is a pleiotropic oncogenic lncRNA in breast cancer. Boosting SOCS3 expression may reverse the oncogenic activities of DANCR and thus provide a therapeutic strategy for breast cancer treatment.

Visceral Adipose Tissue Inflammatory Factors (TNF-Alpha, SOCS3) in Gestational Diabetes (GDM): Epigenetics as a Clue in GDM Pathophysiology

Gestational diabetes (GDM) is among the most challenging diseases in westernized countries, affecting mother and child, immediately and in later life. Obesity is a major risk factor for GDM. However, the impact visceral obesity and related epigenetics play for GDM etiopathogenesis have hardly been considered so far. Our recent findings within the prospective ‘EaCH’ cohort study of women with GDM or normal glucose tolerance (NGT), showed the role, critical factors of insulin resistance (i.e., adiponectin, insulin receptor) may have for GDM pathophysiology with epigenetically modified expression in subcutaneous (SAT) and visceral (VAT) adipose tissues. Here we investigated the expression and promoter methylation of key inflammatory candidates, tumor necrosis factor-alpha (TNF-α) and suppressor of cytokine signaling 3 (SOCS3) in maternal adipose tissues collected during caesarian section (GDM, n = 19; NGT, n = 22). The mRNA expression of TNF-α and SOCS3 was significantly increased in VAT, but not in SAT, of GDM patients vs. NGT, accompanied by specific alterations of respective promoter methylation patterns. In conclusion, we propose a critical role of VAT and visceral obesity for the pathogenesis of GDM, with epigenetic alterations of the expression of inflammatory factors as a potential factor.

Influenza Virus-Induced Robust Expression of SOCS3 Contributes to Excessive Production of IL-6

Influenza A virus (IAV) remains a major public health threat in the world, as indicated by the severe pneumonia caused by its infection annually. Interleukin-6 (IL-6) involved excessive inflammatory response to IAV infection profoundly contributes to the virus pathogenesis. However, the precise mechanisms underlying such a response are poorly understood. Here we found from both in vivo and in vitro studies that IAV not only induced a surge of IL-6 release, but also greatly upregulated expression of suppressor of cytokine signaling-3 (SOCS3), the potent suppressor of IL-6-associated signal transducer and activator of transcription 3 (STAT3) signaling. Interestingly, there existed a cytokine-independent mechanism of the robust induction of SOCS3 by IAV at early stages of the infection. Furthermore, we employed SOCS3-knockdown transgenic mice (TG), and surprisingly observed from virus challenge experiments using these mice that disruption of SOCS3 expression provided significant protection against IAV infection, as evidenced by attenuated acute lung injury, a higher survival rate of infected animals and lower viral load in infected tissues as compared with those of wild-type littermates under the same condition. The activity of nuclear factor-kappa B (NFκB) and the expression of its target gene IL-6 were suppressed in SOCS3-knockdown A549 cells and the TG mice after infection with IAV. Moreover, we defined that enhanced STAT3 activity caused by SOCS3 silencing was important for the regulation of NFκB and IL-6. These findings establish a critical role for IL-6-STAT3-SOCS3 axis in the pathogenesis of IAV and suggest that influenza virus may have evolved a strategy to circumvent IL-6/STAT3-mediated immune response through upregulating SOCS3.

Promoter methylation and expression of SOCS3 affect the clinical outcome of pediatric acute lymphoblastic leukemia by JAK/STAT pathway

Suppressor of cytokine signaling 3 (SOCS3) has been characterized as one of the most crucial negative regulator in the JAK2/STAT3 signaling pathway. However, there are few studies on the relationship between SOCS3 and pediatric acute lymphoblastic leukemia (ALL). This study analyzes the influence of SOCS3 expression on the risk and the progression of pediatric ALL and the underlying mechanism. The levels of SOCS3, p-JAK2, p-STAT3, SOCS3 methylation, CD4+CD25+CD127lowTreg were detected by PCR, laser confocal microscopy, western blot, bisulfite sequencing and flow cytometry at different progression of ALL. We found that the SOCS3 expression level at initial diagnosis (DG) of ALL patients was significantly lower than that of healthy controls (HC), while the expression of SOCS3 methylation was opposite. The expression of SOCS3 and SOCS3 methylation were returned to normal in the complete remission (CR) stage, and there were no difference between resistance, relapse and initial diagnosis. The expression of SOCS3 decreased and weakened the inhibition of pSTAT3 expression in DG, resistance and relapse groups. The levels of Treg cells in ALL children were significantly higher than those in the HC children. There was a positive correlation between the expression level of STAT3 and the expression level of Treg cells in children with ALL, while that was negatively correlated with the expression levels of Treg cells. Compared with high-level of SOCS3, the low-level of SOCS3 patients had more high risk factors, as higher WBC counts, LDH level and much more poor prognostic genes. SOCS3 methylation leads to low-expression of SOCS3, which can lead to continuous activation of JAK/STAT3 and increased expression of Treg cells, which in turn affects the anti-tumor immunological effect of the body. Taken together, our data show that monitoring the level of SOCS3 can contribute to the understanding of the state of illness and evaluate the risk of progression of ALL.

Nephrotoxicity instead of immunotoxicity of OTA is induced through DNMT1-dependent activation of JAK2/STAT3 signaling pathway by targeting SOCS3

Ochratoxin A (OTA) is reported to induce nephrotoxicity and immunotoxicity in animals and humans. However, the underlying mechanism and the effects of OTA on DNA damage have not been reported until now. The present study aims to investigate OTA-induced cytotoxicity and DNA damage and the underlying mechanism in PK15 cells and PAMs. The results showed that OTA at 2.0-8.0 µg/mL for 24 h induced cytotoxicity and DNA damage in PK15 cells and PAMs as demonstrated by decreasing cell viabilities and mRNA levels of DNA repair genes (OGG1, NEIL1 and NEIL3), increasing LDH release, Annexin V staining cells, apoptotic nuclei and the accumulation of γ-H2AX foci. OTA at 2.0-8.0 µg/mL increased DNMT1 and SOCS3 mRNA expressions about 2-4 fold in PK15 cells or 1.3-2 fold in PAMs. OTA at 2.0-8.0 µg/mL increased DNMT1, SOCS3, JAK2 and STAT3 protein expressions in PK15 cells or PAMs. DNMT inhibitor (5-Aza-2-dc), promoted SOCS3 expression, inhibited JAK2 and STAT3 expression, alleviated cytotoxicity, apoptosis and DNA damage induced by OTA at 4.0 µg/mL in PK15 cells. While, in PAMs, 5-Aza-2-dc had no effects on SOCS3 expression induced by OTA at 4.0 µg/mL, but inhibited JAK2 and STAT3 expression, and alleviated cytotoxicity, apoptosis and DNA damage induced by OTA. JAK inhibitor (AG490) or STAT3-siRNA alleviated OTA-induced cytotoxicity and DNA damage in PK15 cells or PAMs. Taken together, nephrotoxicity instead of immunotoxicity of OTA is induced by targeting SOCS3 through DNMT1-mediated JAK2/STAT3 signaling pathway. These results provide a scientific and new explanation of the underlying mechanism of OTA-induced nephrotoxicity and immunotoxicity.

Inhibition of DNA methyltransferase-1 instigates the expression of DNA methyltransferase-3a in angioplasty-induced restenosis

Increased expression of DNA methyltransferase-1 (DNMT1) associates with the progression of many human diseases. Because DNMT1 induces cell proliferation, drugs that inhibit DNMT1 have been used to treat proliferative diseases. Because these drugs are nonspecific inhibitors of DNMT1, subsidiary events or the compensatory mechanisms that are activated in the absence of DNMT1 limit their therapeutic application. Here, we studied the molecular mechanisms that occur during angioplasty-induced restenosis and found that DNMT1 inhibition in both in vitro and in vivo approaches resulted in the induction of DNA methyltransferase-3a (DNMT3a) expression. In vascular smooth muscle cells (VSMCs), the microRNA hsa-miR-1264 mimic, specifically inhibiting DNMT1, induced nuclear expression of DNMT3a. On the contrary, there was no induced expression of DNMT3a in VSMCs that were transfected with hsa-miR-1264 inhibitor. Further, ectopic expression of suppressor of cytokine signaling 3 (SOCS3) through adeno-associated virus (AAV)-mediated gene delivery in the coronary arteries of Yucatan microswine showed inhibition of both DNMT1 and DNMT3a in vivo. These findings show the existence of an inter-regulatory mechanism between DNMT1 and DNMT3a where, in the absence of DNMT1, induction of DNMT3a compensates for the loss of DNMT1 functions, suggesting that the inhibition of both DNMT1 and DNMT3a are required to prevent restenosis.

Epigenetics of Mucus Hypersecretion in Chronic Respiratory Diseases

Asthma, chronic obstructive pulmonary disease, and cystic fibrosis are three chronic pulmonary diseases that affect an estimated 420 million individuals across the globe. A key factor contributing to each of these conditions is mucus hypersecretion. Although management of these diseases is vastly studied, researchers have only begun to scratch the surface of the mechanisms contributing to mucus hypersecretion. Epigenetic regulation of mucus hypersecretion, other than microRNA post-translational modification, is even more scarcely researched. Detailed study of epigenetic mechanisms, such as DNA methylation and histone modification, could not only help to better the understanding of these respiratory conditions but also reveal new treatments for them. Because mucus hypersecretion is such a complex event, there are innumerable genes involved in the process, which are beyond the scope of a single review. Therefore, the purpose of this review is to narrow the focus and summarize specific epigenetic research that has been conducted on a few aspects of mucus hypersecretion in asthma, chronic obstructive pulmonary disease, cystic fibrosis, and some cancers. Specifically, this review emphasizes the contribution of DNA methylation and histone modification of particular genes involved in mucus hypersecretion to identify possible targets for the development of future therapies for these conditions. Elucidating the role of epigenetics in these respiratory diseases may provide a breath of fresh air to millions of affected individuals around the world.

PPARγ alleviated hepatocyte steatosis through reducing SOCS3 by inhibiting JAK2/STAT3 pathway

Peroxisome proliferator-activated receptor gamma (PPARγ) participates in the process of insulin resistance (IR), a crucial pathophysiology in non-alcoholic fatty liver disease (NAFLD). Meanwhile, suppressor of cytokine signaling3 (SOCS3) also regulates IR in NAFLD. Both PPARγ and SOCS3 play a role in NAFLD through regulating IR, while it is unclear whether these two proteins interact to regulate hepatic steatosis. PPARγ, SOCS3 and its associated JAK2/STAT3 pathway were analyzed using Kuppfer cells (KCs) treatment with LPS and BRL-3A cells treatment with palmitic acid, KC-conditioned medium (KCCM), PPARγ agonist rosiglitazone (ROZ) or JAK2 inhibitor AG490 to demonstrate the role of PPARγ and SOCS3 in hepatocytes steatosis. As LPS concentration increasing, phagocytosis activity of KCs decreased; but releasing of TNF-α and IL-6 increased. After treatment with KCCM, mRNA level of SOCS3, JAK2 and STAT3 as well as protein expression of SOCS3, p-JAK2 and p-STAT3 in steatosis BRL-3A cells increased significantly, which were inhibited by AG490 or ROZ treatment. Taken together, these results indicated that KCCM attributed to KCs dysfunction facilitated hepatocyte steatosis through promoting expressing SOCS3; but PPARγ agonist ROZ alleviated steatosis through reducing SOCS3 expression by inhibiting JAK2/STAT3 in hepatocytes.

Exendin-4 inhibits high-altitude cerebral edema by protecting against neurobiological dysfunction

The anti-inflammatory and antioxidant effects of exendin-4 (Ex-4) have been reported previously. However, whether (Ex-4) has anti-inflammatory and antioxidant effects on high-altitude cerebral edema (HACE) remains poorly understood. In this study, two rat models of HACE were established by placing rats in a hypoxic environment with a simulated altitude of either 6000- or 7000-m above sea level (MASL) for 72 hours. An altitude of 7000 MASL with 72-hours of hypoxia was found to be the optimized experimental paradigm for establishing HACE models. Then, in rats where a model of HACE was established by introducing them to a 7000 MASL environment with 72-hours of hypoxia treatment, 2, 10 and, 100 μg of Ex-4 was intraperitoneally administrated. The open field test and tail suspension test were used to test animal behavior. Routine methods were used to detect change in inflammatory cells. Hematoxylin-eosin staining was performed to determine pathological changes to brain tissue. Wet/dry weight ratios were used to measure brain water content. Evans blue leakage was used to determine blood-brain barrier integrity. Enzyme-linked immunosorbent assay (ELISA) was performed to measure markers of inflammation and oxidative stress including superoxide dismutase, glutathione, and malonaldehyde values, as well as interleukin-6, tumor necrosis factor-alpha, cyclic adenosine monophosphate levels in the brain tissue. Western blot analysis was performed to determine the levels of occludin, ZO-1, SOCS-3, vascular endothelial growth factor, EPAC1, nuclear factor-kappa B, and aquaporin-4. Our results demonstrate that Ex-4 preconditioning decreased brain water content, inhibited inflammation and oxidative stress, alleviated brain tissue injury, maintain blood-brain barrier integrity, and effectively improved motor function in rat models of HACE. These findings suggest that Ex-4 exhibits therapeutic potential in the treatment of HACE.

Methylation of the suppressor of cytokine signaling 3 gene (SOCS3) in bladder cancer

BACKGROUND

It has been identified consequences of dysregulation of JAK-STAT signalling, particularly in regard to JAK-STAT signalling that has been shown to have roles in the oncogenesis of several cell types. SOCS3 protein, the negative regulatory protein of JAK-STAT signaling pathway, may also plays critical regulatory roles in cancer initiation and progression. SOCS3 promoter hypermethylation has often been identified in human cancers; however, the precise role of SOCS3 in bladder cancer is unclear.

METHODS

The methylation status of the SOCS3 was analyzed in an age (±5 years) and sex-matched case-control study, including 112 bladder cancer cases and 118 normal controls, using the MassARRAY EpiTYPER system.

RESULTS

Methylation rate of JAK2, SOCS3 and STAT3 gene were shown to vary among different CpG island. The methylation rate of SOCS3 gene was also much higher in BCa than in normal control participants, but the methylation rate of JAK2, STAT3 gene weren't different in Bca and normal control participants.

CONCLUSIONS

Our study demonstrates that promoter hypermethylation of SOCS3 gene is associated with BCa and thus, may serve as an independent prognostic biomarker.

TNFR2 Stimulation Promotes Mitochondrial Fusion via Stat3- and NF-kB-Dependent Activation of OPA1 Expression

Supplemental Digital Content is available in the text.

Rationale:

Mitochondria are important cellular organelles and play essential roles in maintaining cell structure and function. Emerging evidence indicates that in addition to having proinflammatory and proapoptotic effects, TNFα (tumor necrosis factor α) can, under certain circumstances, promote improvements in mitochondrial integrity and function, phenomena that can be ascribed to the existence of TNFR2 (TNFα receptor 2).

Objective:

The present study aimed to investigate whether and how TNFR2 activation mediates the effects of TNFα on mitochondria.

Methods and Results:

Freshly isolated neonatal mouse cardiac myocytes treated with shRNA targeting TNFR1 were used to study the effects of TNFR2 activation on mitochondrial function. Neonatal mouse cardiac myocytes exhibited increases in mitochondrial fusion, a change that was associated with increases in mitochondrial membrane potential, intracellular ATP levels, and oxygen consumption capacity. Importantly, TNFR2 activation–induced increases in OPA1 (optic atrophy 1) protein expression were responsible for the above enhancements, and these changes could be attenuated using siRNA targeting OPA1. Moreover, both Stat3 and RelA bound to the promoter region of OPA1 and their interactions synergistically upregulated OPA1 expression at the transcriptional level. Stat3 acetylation at lysine 370 or lysine 383 played a key role in the ability of Stat3 to form a supercomplex with RelA. Meanwhile, p300 modulated Stat3 acetylation in HEK293T (human embryonic kidney 293T) cells, and p300-mediated Stat3/RelA interactions played an indispensable role in OPA1 upregulation. Finally, TNFR2 activation exerted beneficial effects on OPA1 expression in an in vivo transverse aortic constriction model, whereby TNFR1-knockout mice exhibited better outcomes than in mice with both TNFR1 and TNFR2 knocked out.

Conclusions:

TNFR2 activation protects cardiac myocytes against stress by upregulating OPA1 expression. This process was facilitated by p300-mediated Stat3 acetylation and Stat3/RelA interactions, leading to improvements in mitochondrial morphology and function.

Nuclear translocation of STAT3 and NF-κB are independent of each other but NF-κB supports expression and activation of STAT3

NF-κB and STAT3 are essential transcription factors in immunity and act at the interface of the transition from chronic inflammation to cancer. Different functional crosstalks between NF-κB and STAT3 have been recently described arguing for a direct interaction of both proteins. During a systematic analysis of NF-κB/STAT3 crosstalk we observed that appearance of the subcellular distribution of NF-κB and STAT3 in immunofluorescence heavily depends on the fixation procedure. Therefore, we established an optimized fixation protocol for the reliable simultaneous analysis of the subcellular distributions of both transcription factors. Using this protocol we found that cytokine-induced nuclear accumulation of NF-κB or STAT3 did not alter the subcellular distribution of the other transcription factor. Both knockout and overexpression of STAT3 does not have any major effect on canonical TNFα-NF-κB signalling in MEF or HeLa cells. Similarly, knockout of p65 did not alter nuclear accumulation of STAT3 in response to IL-6. However, p65 expression correlates with elevated total cellular levels of STAT3 and STAT1 and supports activation of these transcription factors. Our findings in MEF cells argue against a direct physical interaction of free cellular NF-κB and STAT3 but point to more intricate functional interactions.

Down-regulation of hsa-miR-1264 contributes to DNMT1-mediated silencing of SOCS3

Previously we found decreased expression of SOCS3 in neointimal hyperplastic region following balloon angioplasty in atherosclerotic micro swine. In our recent in vitro studies using human coronary artery smooth muscle cells (HCASMC), we observed the inhibition of SOCS3 expression in the presence of both TNF-α and IGF-1, correlating with the in vivo findings in microswine. We also reported that two independent mechanisms, JAK/STAT3/NFκB and promoter methylation of SOCS3 were responsible for TNF-α and IGF-1 induced SOCS3 inhibition. In this study, using miRNA array and gene expression approaches, we explored the molecular mechanisms involved in the above SOCS3 repression and identified several miRNAs that are associated with the regulation of SOCS3 expression. Our miRNA expression profiling revealed profound down-regulation of two specific miRNAs, hsa-miR-758 and hsa-miR-1264, whose expression levels were decreased by 8-10 folds in HCASMCs that were treated with both TNF-α and IGF-1. This was accompanied with a significant up-regulation of three specific miRNAs, hsa-miR-155, hsa-miR-146b-5p and hsa-miR-146a, which showed about 3-7 fold increases in their expression levels. Importantly, we also found that the miRNA hsa-miR-1264 targets DNA methyltransferase-1 (DNMT1) transcripts by binding to its 3'UTR region to affect its expression. Expression of hsa-miR-1264 in HCASMCs not only resulted in decreased DNMT1 mRNA transcripts but it also increased SOCS3 expression. The treatment with TNF-α and IGF-1 resulted in drastic decrease in hsa-miR-1264 levels with no change in the expression of DNMT1. Consequently, the DNMT1 activity caused hypermethylation in the CpG island of the SOCS3 promoter region and inhibited its expression. This could be a causative epigenetic mechanism associated with TNF-α and IGF-1 induced smooth muscle cell proliferation involved in the pathogenesis of coronary artery hyperplasia and restenosis.

Transcriptional repression of SOCS3 mediated by IL-6/STAT3 signaling via DNMT1 promotes pancreatic cancer growth and metastasis

BACKGROUND

Previous studies have investigated the sustained aberrantly activated Interleukin-6 (IL-6)/signal transducer and activator of transcription 3 (STAT3) signaling pathway is crucial for pancreatic cancer growth and metastasis. Suppressor of cytokine signaling 3 (SOCS3), as a key negative feedback regulator of this signaling pathway, is usually down-regulated in various cancers. In the present study, we aim at exploring the biological function and the underlying molecular regulation mechanisms of SOCS3 in pancreatic cancer.

METHODS

The expression of SOCS3 and other genes in pancreatic cancer was examined by Quantitative real-time PCR, western blotting and immunohistochemical staining. The interaction between pSTAT3 and DNA Methyltransferase 1 (DNMT1) was investigated by co-immunoprecipitation assay. Luciferase reporter assay was used to investigate the transcriptional regulation of pSTAT3 and DNMT1 on the SOCS3 gene. The effects of SOCS3 on the biological behavior of pancreatic cancer cells were assessed both in vitro and vivo. Furthermore, we performed a comprehensive analysis of the expression of SOCS3 in a pancreatic cancer tissue microarray (TMA) and correlated our findings with pathological parameters and outcomes of the patients.

RESULTS

We showed that SOCS3 expression was decreased in phosphorylated STAT3 (pSTAT3)-positive tumors and was negatively correlated with pSTAT3 in pancreatic cancer cells. We also found that IL-6/STAT3 promoted SOCS3 promoter hypermethylation by increasing DNMT1 activity; silencing DNMT1 or 5-aza-2-deoxycytidine (5-AZA) treatment could reverse the down-regulation of SOCS3 mediated by IL-6. Using co-immunoprecipitation and luciferase reporter assays, we found that STAT3 recruited DNMT1 to the promoter region of SOCS3 and inhibited its transcriptional activity. Overexpression of SOCS3 significantly inhibited cell proliferation, which may be due to the increase in G1-S phase arrest; overexpression of SOCS3 also inhibited cell migration and invasion as well as tumorigenicity in nude mice. Pancreatic cancer tissue microarray analysis showed that high SOCS3 expression was a good prognostic factor and negatively correlated with tumor volume and metastasis.

CONCLUSION

We demonstrated that activated IL-6/STAT3 signaling could induce SOCS3 methylation via DNMT1, which led to pancreatic cancer growth and metastasis. These data also provided a mechanistic link between sustained aberrantly activated IL-6/STAT3 signaling and SOCS3 down-regulation in pancreatic cancer. Thus, inhibitors of STAT3 or DNMT1 may become novel strategies for treating pancreatic cancer.

Methylation and microRNA-mediated epigenetic regulation of SOCS3

Epigenetic gene silencing of several genes causes different pathological conditions in humans, and DNA methylation has been identified as one of the key mechanisms that underlie this evolutionarily conserved phenomenon associated with developmental and pathological gene regulation. Recent advances in the miRNA technology with high throughput analysis of gene regulation further increased our understanding on the role of miRNAs regulating multiple gene expression. There is increasing evidence supporting that the miRNAs not only regulate gene expression but they also are involved in the hypermethylation of promoter sequences, which cumulatively contributes to the epigenetic gene silencing. Here, we critically evaluated the recent progress on the transcriptional regulation of an important suppressor protein that inhibits cytokine-mediated signaling, SOCS3, whose expression is directly regulated both by promoter methylation and also by microRNAs, affecting its vital cell regulating functions. SOCS3 was identified as a potent inhibitor of Jak/Stat signaling pathway which is frequently upregulated in several pathologies, including cardiovascular disease, cancer, diabetes, viral infections, and the expression of SOCS3 was inhibited or greatly reduced due to hypermethylation of the CpG islands in its promoter region or suppression of its expression by different microRNAs. Additionally, we discuss key intracellular signaling pathways regulated by SOCS3 involving cellular events, including cell proliferation, cell growth, cell migration and apoptosis. Identification of the pathway intermediates as specific targets would not only aid in the development of novel therapeutic drugs, but, would also assist in developing new treatment strategies that could successfully be employed in combination therapy to target multiple signaling pathways.

SOCS3 Methylation Predicts a Poor Prognosis in HBV Infection-Related Hepatocellular Carcinoma

Suppressor of cytokine signaling 3 (SOCS3) plays crucial roles in JAK/STAT signaling pathway inhibition in hepatocellular carcinoma (HCC). However, the methylation status of SOCS3 in HBV infection-related HCC and the relationship between SOCS3 methylation and the clinical outcome remain unknown. Here, we reported that in HCC tumor tissues, two regions of the CpG island (CGI) in the SOCS3 promoter were subjected to methylation analysis and only the region close to the translational start site of SOCS3 was hypermethylated. In HCC tumor tissues, SOCS3 showed an increased methylation frequency and intensity compared with that in the adjacent non-tumor tissues. Moreover, SOCS3 expression was significantly down-regulated in HCC cell lines and tumor tissues, and this was inversely correlated with methylation. Kaplan-Meier curve analysis revealed that in patients with an hepatitis B virus (HBV) infection background, SOCS3 hypermethylation was significantly correlated with a poor clinical outcome of HCC patients. Our findings indicated that SOCS3 hypermethylation has already happened in non-tumor tissues and increased in both frequency and intensity in tumor tissues. This suggests that the methylation of SOCS3 could predict a poor prognosis in HBV infection-related HCC patients.

Characterization of the roles of suppressor of cytokine signaling-3 in prostate cancer development and progression

As negative feedback regulators of cytokine signaling, suppressor of cytokine signaling proteins are induced by interleukins and various peptide hormones and may prevent sustained activation of signaling pathways. In particular, suppressor of cytokine signaling-3 (SOCS-3) plays pivotal roles in the development and progression of various cancers and exerts pleiotropic effects on cell proliferation and apoptosis. In recent years, abnormal expression of SOCS-3 and its multiple functions have been extensively investigated in human carcinomas, particularly in prostate cancer. SOCS-3 can act as an oncogene or a tumor suppressor depending on the cellular context. In this review, we focus on the role of SOCS-3 in prostate cancer development and prognosis, as well as the potential of SOCS-3 as a therapeutic target and diagnostic marker.

The relevance of epigenetics to occlusive cerebral and peripheral arterial disease

Athero-thrombosis of the arteries supplying the brain and lower limb are the main causes of stroke and limb loss. New therapies are needed to improve the outcomes of athero-thrombosis. Recent evidence suggests a role for epigenetic changes in the development and progression of ischaemic injury due to atherosclerotic occlusion of peripheral arteries. DNA hypermethylation have been associated with cardiovascular diseases. Histone post-translational modifications have also been implicated in atherosclerosis. Oxidized low-density lipoprotein regulated pro-inflammatory gene expression within endothelial cells is controlled by phosphorylation/acetylation of histone H3 and acetylation of histone H4 for example. There are a number of challenges in translating the growing evidence implicating epigenetics in atherosclerosis to improved therapies for patients. These include the small therapeutic window in conditions such as acute stroke and critical limb ischaemia, since interventions introduced in such patients need to act rapidly and be safe in elderly patients with many co-morbidities. Pre-clinical animal experiments have also reported conflicting effects of some novel epigenetic drugs, which suggest that further in-depth studies are required to better understand their efficacy in resolving ischaemic injury. Effective ways of dealing with these challenges are needed before epigenetic approaches to therapy can be introduced into practice.

The future of EPAC-targeted therapies: agonism versus antagonism

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Although tractable to drug development, targeting of cAMP signalling has side effects.

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Selectively targeting EPAC1 and EPAC2 cAMP sensor enzymes may limit some of these off-target effects.

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EPAC agonists could be used to treat vascular inflammation (EPAC1) or type 2 diabetes (EPAC2).

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EPAC1 and EPAC2 antagonists could be used to treat heart disease.

Pharmaceutical manipulation of cAMP levels exerts beneficial effects through the regulation of the exchange protein activated by cAMP (EPAC) and protein kinase A (PKA) signalling routes. Recent attention has turned to the specific regulation of EPAC isoforms (EPAC1 and EPAC2) as a more targeted approach to cAMP-based therapies. For example, EPAC2-selective agonists could promote insulin secretion from pancreatic β cells, whereas EPAC1-selective agonists may be useful in the treatment of vascular inflammation. By contrast, EPAC1 and EPAC2 antagonists could both be useful in the treatment of heart failure. Here we discuss whether the best way forward is to design EPAC-selective agonists or antagonists and the current strategies being used to develop isoform-selective, small-molecule regulators of EPAC1 and EPAC2 activity.

A molecular profile of cocaine abuse includes the differential expression of genes that regulate transcription, chromatin, and dopamine cell phenotype

Chronic drug abuse, craving, and relapse are thought to be linked to long-lasting changes in neural gene expression arising through transcriptional and chromatin-related mechanisms. The key contributions of midbrain dopamine (DA)-synthesizing neurons throughout the addiction process provide a compelling rationale for determining the drug-induced molecular changes that occur in these cells. Yet our understanding of these processes remains rudimentary. The postmortem human brain constitutes a unique resource that can be exploited to gain insights into the pathophysiology of complex disorders such as drug addiction. In this study, we analyzed the profiles of midbrain gene expression in chronic cocaine abusers and well-matched drug-free control subjects using microarray and quantitative PCR. A small number of genes exhibited robust differential expression; many of these are involved in the regulation of transcription, chromatin, or DA cell phenotype. Transcript abundances for approximately half of these differentially expressed genes were diagnostic for assigning subjects to the cocaine-abusing vs control cohort. Identification of a molecular signature associated with pathophysiological changes occurring in cocaine abusers' midbrains should contribute to the development of biomarkers and novel therapeutic targets for drug addiction.

Exhaustive exercise modifies different gene expression profiles and pathways in LPS-stimulated and un-stimulated whole blood cultures

Exhaustive exercise can interfere with immunity, causing transient immunosuppression and infections/inflammation in athletes. We used microarray technology to analyze the gene expression profiles of whole blood in short time (1h) LPS-stimulated and un-stimulated cultures drawn before, 30min after, 3h after and 24h after a half-marathon run. Four male and 4 female athletes participated. Exercise induced differential expression of genes known to be involved in innate immunity/inflammatory response, metabolic response, DNA methylation, apoptosis and regulation of brain function. Several genes with prominent anti-inflammatory function were up-regulated in un-stimulated cultures, including ARG-1, SOCS3, DUSP-1, ORMs, IRAK3, and GJB6. Some of these genes were also strongly up-regulated in LPS-stimulated cultures (ARG-1, ORM2, and GJB6). Some genes were strongly up-regulated through exercise in LPS-stimulated cultures, but not in un-stimulated cultures (TNIP3, PLAU, and HIVEP1). There was also a row of genes, which were strongly down-regulated by exercise in LPS-stimulated cultures, notably IFN-β1 and CXCL10. Exercise also significantly changed the expression of genes (OLIG2, TMEM106B) which are known to be related to brain function and expression of which has never been documented in peripheral blood. In summary, exhaustive exercise, in addition to modifying gene expression in un-stimulated cells, could also interfere with the early gene expression response to endotoxin. There was an anti-inflammatory bias of gene regulation by exercise, including genes involved in the negative regulation of TLRs signalling. The results of the present study demonstrate that some potentially important effects of exercise can only be detected in relation to pathogen stimulation.

Role of Ubiquitylation in Controlling Suppressor of Cytokine Signalling 3 (SOCS3) Function and Expression

The realisation that unregulated activation of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway is a key driver of a wide range of diseases has identified its components as targets for therapeutic intervention by small molecule inhibitors and biologicals. In this review, we discuss JAK-STAT signalling pathway inhibition by the inducible inhibitor "suppressor of cytokine signaling 3 (SOCS3), its role in diseases such as myeloproliferative disorders, and its function as part of a multi-subunit E3 ubiquitin ligase complex. In addition, we highlight potential applications of these insights into SOCS3-based therapeutic strategies for management of conditions such as vascular re-stenosis associated with acute vascular injury, where there is strong evidence that multiple processes involved in disease progression could be attenuated by localized potentiation of SOCS3 expression levels.

IL-23 selectively promotes the metastasis of colorectal carcinoma cells with impaired Socs3 expression via the STAT5 pathway

Interleukin-23 (IL-23) is a conventional proinflammatory IL related to colorectal carcinoma (CRC). The signal transducer and activator of transcription (STAT) and suppressors of cytokine signaling (Socs) molecules, respectively, serve as agonists and antagonists of IL-23-associated inflammation. However, it remains unknown whether IL-23 directly affects CRC metastasis. In this study, we measured the metastasis of several human CRC cell lines stimulated by IL-23 in vitro and in vivo. Interestingly, the prometastasis effect of IL-23 was observed only in SW-620 cells. IL-23-associated migration and invasion was mediated by the phosphorylation of STAT5. The expression of Socs3 in SW-620 was impaired by IL-23 via DNA methylation and DNA methyltransferase-1 (DNMT-1)-dependent way. The DNMT-1-associated regulation was not observed in the other three cells. Socs3 was further confirmed to inhibit the prometastatic function of IL-23 both in vitro and in vivo. We analyzed the clinical correlation between the level of IL-23 in tumors and the metastasis of CRC and found that higher IL-23 levels along with lower Socs3 in CRC tissues accounted for more metastatic cases. In conclusion, it was demonstrated that IL-23, assisted by STAT5, might only promote the metastasis of CRC with deficient Socs3 expression in which IL-23-induced DNMT-1 was involved. It was elucidated that Socs3 seemed to be one of the important factors that mediate the selectivity of IL-23. Taken together, these discoveries give rise to new insights into the role of IL-23 in cancer biology and provide additional preclinical data regarding IL-23-associated therapy for CRC.