A family of cytokine-inducible inhibitors of signalling

Suppressor of cytokine signaling 2 is induced in Huntington's disease and involved in autophagy

Suppressor of cytokine signaling (SOCS) proteins are primarily feedback inhibitors of cytokine signaling. The two conserved domains of SOCS proteins have distinct functions. Src homology 2 (SH2) domain inhibits cytokine receptor, while SOCS box acts as an E3 ubiquitin ligase. SOCS2, a cytokine signaling suppressor, has been primarily implicated in regulating inflammatory conditions in neuronal diseases. However, SOCS proteins have been suggested to play diverse roles in healthy and diseased nervous system including neurodegenerative disorders. In this study, SOCS2 was found to be upregulated in Huntington's disease and was substantially induced in extended polyglutamine (polyQ)-expressing striatal cells. The induced level was augmented under aging conditions. In extended polyQ-expressing cells, downregulated SOCS2 improved autophagic dysfunction rather than altered inflammatory conditions. Overall, we suggest that SOCS2 involves in regulating autophagy by functioning as an E3 ligase in extended polyQ conditions, and consequently regulates cell damage and cell death type.

People with HIV-1 demonstrate type 1 interferon refractoriness associated with upregulated USP18

HIV-1 infection persists in humans despite expression of antiviral type 1 interferons (IFN). Even exogenous administration of IFNα only marginally reduces HIV-1 abundance, raising the hypothesis that people living with HIV-1 (PLWH) are refractory to type 1 IFN. We demonstrated type 1 IFN refractoriness in CD4+ and CD8+ T cells isolated from HIV-1 infected persons by detecting diminished STAT1 phosphorylation (pSTAT1) and interferon-stimulated gene (ISG) induction upon type 1 IFN stimulation compared to healthy controls. Importantly, HIV-1 infected people who were virologically suppressed with antiretrovirals also showed type 1 IFN refractoriness. We found that USP18 levels were elevated in people with refractory pSTAT1 and ISG induction and confirmed this finding ex vivo in CD4+ T cells from another cohort of HIV-HCV coinfected persons who received exogenous pegylated interferon-α2b in a clinical trial. We used a cell culture model to recapitulate type 1 IFN refractoriness in uninfected CD4+ T cells that were conditioned with media from HIV-1 inoculated PBMCs, inhibiting de novo infection with antiretroviral agents. In this model, RNA interference against USP18 partly restored type 1 IFN responses in CD4+ T cells. We found evidence of type 1 IFN refractoriness in PLWH irrespective of virologic suppression that was associated with upregulated USP18, a process that might be therapeutically targeted to improve endogenous control of infection.ImportancePeople living with HIV-1 (PLWH) have elevated constitutive expression of type 1 interferons (IFN). However, it is unclear whether this impacts downstream innate immune responses. We identified refractory responses to type 1 IFN stimulation in T cells from PLWH, independent of antiretroviral treatment. Type 1 IFN refractoriness was linked to elevated USP18 levels in the same cells. Moreover, we found that USP18 levels predicted the anti-HIV-1 effect of type 1 IFN-based therapy on PLWH. In vitro, we demonstrated that refractory type 1 IFN responses were transferrable to HIV-1 uninfected target CD4+ T cells, and this phenomenon was mediated by type 1 IFN from HIV-1 infected cells. Type 1 IFN responses were partially restored by USP18 knockdown. Our findings illuminate a new mechanism by which HIV-1 contributes to innate immune dysfunction in PLWH, through the continuous production of type 1 IFN that induces a refractory state of responsiveness.

The role of SOCS proteins in the development of virus- induced hepatocellular carcinoma

Background

Liver cancer has become one of the most common cancers and has a high mortality rate. Hepatocellular carcinoma is one of the most common liver cancers, and its occurrence and development process are associated with chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections.

Main body

The serious consequences of chronic hepatitis virus infections are related to the viral invasion strategy. Furthermore, the viral escape mechanism has evolved during long-term struggles with the host. Studies have increasingly shown that suppressor of cytokine signaling (SOCS) proteins participate in the viral escape process. SOCS proteins play an important role in regulating cytokine signaling, particularly the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway. Cytokines stimulate the expression of SOCS proteins, in turn, SOCS proteins inhibit cytokine signaling by blocking the JAK-STAT signaling pathway, thereby achieving homeostasis. By utilizing SOCS proteins, chronic hepatitis virus infection may destroy the host’s antiviral responses to achieve persistent infection.

Conclusions

This review provides recent knowledge regarding the role of SOCS proteins during chronic hepatitis virus infection and provides some new ideas for the future treatment of chronic hepatitis.

Microtubule-dependent mechanism of anti-inflammatory effect of SOCS1 in endothelial dysfunction and lung injury

Suppressors of cytokine signaling (SOCS) provide negative regulation of inflammatory reaction. The role and precise cellular mechanisms of SOCS1 in control of endothelial dysfunction and barrier compromise associated with acute lung injury remain unexplored. Our results show that siRNA-mediated SOCS1 knockdown augmented lipopolysaccharide (LPS)-induced pulmonary endothelial cell (EC) permeability and enhanced inflammatory response. Consistent with in vitro data, EC-specific SOCS1 knockout mice developed more severe lung vascular leak and accumulation of inflammatory cells in bronchoalveolar lavage fluid. SOCS1 overexpression exhibited protective effects against LPS-induced endothelial permeability and inflammation, which were dependent on microtubule (MT) integrity. Biochemical and image analysis of unstimulated EC showed SOCS1 association with the MT, while challenge with LPS or MT depolymerizing agent colchicine impaired this association. SOCS1 directly interacted with N2 domains of MT-associated proteins CLIP-170 and CLASP2. Furthermore, N-terminal region of SOCS1 was indispensable for these interactions and SOCS1-ΔN mutant lacking N-terminal 59 amino acids failed to rescue LPS-induced endothelial dysfunction. Depletion of endogenous CLIP-170 or CLASP2 abolished SOCS1 interaction with Toll-like receptor-4 and Janus kinase-2 leading to impairment of SOCS1 inhibitory effects on LPS-induced inflammation. Altogether, these findings suggest that endothelial barrier protective and anti-inflammatory effects of SOCS1 are critically dependent on its targeting to the MT.

Multi-omics links IL-6 trans-signalling with neutrophil extracellular trap formation and Haemophilus infection in COPD

BACKGROUND

IL-6 trans-signalling (IL-6TS) is emerging as a pathogenic mechanism in chronic respiratory diseases, however the drivers of IL-6TS in the airways and the phenotypic characteristic of patients with increased IL-6TS pathway activation remain poorly understood.

OBJECTIVE

Our aim was to identify and characterize COPD patients with increased airway IL-6TS and to elucidate the biological drivers of IL-6TS pathway activation.

METHODS

We used an IL-6TS-specific sputum biomarker profile (sIL-6R, IL-6, IL-1β, IL-8, MIP-1β) to stratify sputum data from patients with COPD (n=74; BEAT-COPD) by hierarchical clustering. The IL-6TS signature was related to clinical characteristics and sputum microbiome profiles. The induction of neutrophil extracellular trap formation (NETosis) and IL-6TS by Haemophilus influenzae were studied in human neutrophils.

RESULTS

Hierarchical clustering revealed an IL-6TS-high subset (n=24) of COPD patients, which shared phenotypic traits with an IL-6TS-high subset previously identified in asthma. The subset was characterized by increased sputum cell counts (p=0.0001), persistent sputum neutrophilia (p=0.0004), reduced quality of life (CRQ total score; p=0.008), and increased levels of pro-inflammatory mediators and MMPs in sputum. IL-6TS-high COPD patients showed an increase in Proteobacteria, with Haemophilus as the dominating genus. NETosis induced by H. influenzae was identified as a potential mechanism for increased soluble IL-6 receptor (sIL-6R) levels. This was supported by a significant positive correlation between sIL-6R and NETosis markers in bronchoalveolar lavage fluid from COPD patients.

CONCLUSION

IL-6TS pathway activation due to chronic colonization with Haemophilus may be an important disease driver in a subset of COPD patients.

Studies in lung cancer cytokine proteomics: a review

INTRODUCTION

Proteins are molecules that have role in the progression of the diseases. Proteomics is a tool that can play an effective role in identifying diagnostic and therapeutic biomarkers for lung cancer. Cytokines are proteins that play a decisive role in activating body's immune system in lung cancer. They can increase the growth of the tumor (oncogenic cytokines) or limit tumor growth (anti-tumor cytokines) by regulating related signaling pathways such as proliferation, growth, metastasis, and apoptosis.

AREAS COVERED

In the present study, a total of 223 papers including 196 research papers and 27 review papers, extracted from PubMed and Scopus and published from 1997 to present, are reviewed. The most important involved-cytokines in lung cancer including TNF-α, IFN- γ, TGF-β, VEGF and interleukins such as IL-6, IL-17, IL-8, IL-10, IL-22, IL-1β and IL-18 are introduced. Also, the pathological and biological role of such cytokines in cancer signaling pathways is explained.

EXPERT OPINION

In lung cancer, the cytokine expression changes under the physiological conditions of the immune system, and inflammatory cytokines are associated with the progression of lung cancer. Therefore, the cytokine expression profile can be used in the diagnosis, prognosis, prediction of therapeutic responses, and survival of patients with lung cancer.

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.

Cytokine inducible SH2-containing protein potentiate J subgroup avian leukosis virus replication and suppress antiviral responses in DF-1 chicken fibroblast cells

Cytokine-inducible Srchomology2 (SH2)-containing protein (CIS) belongs to the suppressors of cytokine signaling (SOCS) protein family function as a negative feedback loop inhibiting cytokine signal transduction. J subgroup avian leukosis virus (ALV-J), a commonly-seen avian virus with a feature of immunosuppression, poses an unmeasurable threat to the poultry industry across the world. However, commercial medicines or vaccines are still no available for this virus. This study aims to evaluate the potential effect of chicken CIS in antiviral response and its role on ALV-J replication. The results showed that ALV-J strain SCAU-HN06 infection induced CIS expression in DF-1 cells, which was derived from chicken embryo free of endogenous avian sarcoma-leukosis virus (ASLV) like sequences. By overexpressing CIS, the expression of chicken type I interferon (IFN-I) and interferon-stimulated genes (ISGs; PKR, ZAP, CH25H, CCL4, IFIT5, and ISG12) were both suppressed. Meanwhile, data showed that CIS overexpression also increased viral yield. Interestingly, knockdown of CIS enhanced induction of IFN-I and ISGs and inhibited viral replication. Collectively, we proved that modulation of CIS expression not only affected SCAU-HN06 replication in vitro but also altered the expression of IFN-I and ISGs that act as an essential part of antiviral innate immune system. Our data provide a potential target for developing antiviral agents for ALV-J.

EBV-induced gene 3 augments IL-23Rα protein expression through a chaperone calnexin

Epstein-Barr virus-induced gene 3 (EBI3) is a subunit common to IL-27, IL-35, and IL-39. Here, we explore an intracellular role of EBI3 that is independent of its function in cytokines. EBI3-deficient naive CD4+ T cells had reduced IFN-γ production and failed to induce T cell-dependent colitis in mice. Similarly reduced IFN-γ production was observed in vitro in EBI3-deficient CD4+ T cells differentiated under pathogenic Th17 polarizing conditions with IL-23. This is because the induction of expression of one of the IL-23 receptor (IL-23R) subunits, IL-23Rα, but not another IL-23R subunit, IL-12Rβ1, was selectively decreased at the protein level, but not the mRNA level. EBI3 augmented IL-23Rα expression via binding to the chaperone molecule calnexin and to IL-23Rα in a peptide-dependent manner, but not a glycan-dependent manner. Indeed, EBI3 failed to augment IL-23Rα expression in the absence of endogenous calnexin. Moreover, EBI3 poorly augmented the expression of G149R, an IL-23Rα variant that protects against the development of human colitis, because binding of EBI3 to the variant was reduced. Taken together with the result that EBI3 expression is inducible in T cells, the present results suggest that EBI3 plays a critical role in augmenting IL-23Rα protein expression via calnexin under inflammatory conditions.

Translational Research in Retinopathy of Prematurity: From Bedside to Bench and Back Again

Retinopathy of prematurity (ROP), a vascular proliferative disease affecting preterm infants, is a leading cause of childhood blindness. Various studies have investigated the pathogenesis of ROP. Clinical experience indicates that oxygen levels are strongly correlated with ROP development, which led to the development of oxygen-induced retinopathy (OIR) as an animal model of ROP. OIR has been used extensively to investigate the molecular mechanisms underlying ROP and to evaluate the efficacy of new drug candidates. Large clinical trials have demonstrated the efficacy of anti-vascular endothelial growth factor (VEGF) agents to treat ROP, and anti-VEGF therapy is presently becoming the first-line treatment worldwide. Anti-VEGF therapy has advantages over conventional treatments, including being minimally invasive with a low risk of refractive error. However, long-term safety concerns and the risk of late recurrence limit this treatment. There is an unmet medical need for novel ROP therapies, which need to be addressed by safe and minimally invasive therapies. The recent progress in biotechnology has contributed greatly to translational research. In this review, we outline how basic ROP research has evolved with clinical experience and the subsequent emergence of new drugs. We discuss previous and ongoing trials and present the candidate molecules expected to become novel targets.

JAK/STAT Dysregulation With SOCS1 Overexpression in Acquired Cholesteatoma-Adjacent Mucosa

IMPORTANCE

Surgery remains the gold standard in cholesteatoma treatment. However, the rate of recurrence is significant and the development of new nonsurgical treatment alternatives is warranted. One of the possible molecular pathways to target is the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway.

OBJECTIVE

To investigate the JAK/STAT pathway in the middle ear mucosa in patients with acquired cholesteatoma compared with middle ear mucosa from healthy controls.

DESIGN

Case-control study.

SETTING

Linköping University Hospital, Sweden, and Karolinska Institutet, Stockholm, Sweden. Sampling period: February 2011 to December 2016.

PARTICIPANTS

Middle ear mucosa from 26 patients with acquired cholesteatoma undergoing tympanoplasty and mastoidectomy, and 27 healthy controls undergoing translabyrinthine surgery for vestibular schwannoma or cochlear implantation was investigated.

MAIN OUTCOMES/MEASURES

The expression of Interleukin-7 receptor alpha, JAK1, JAK2, JAK3, STAT5A, STAT5B, and suppressor of cytokine signaling-1 (SOCS1) were quantified using quantitative polymerase chain reaction. In addition, expression level of cyclin D2, transforming growth factor beta 1, thymic stromal lymphopoietin, CD3, and CD19 was evaluated.

RESULTS

In cholesteatoma-adjacent mucosa, SOCS1 was significantly upregulated (p= 0.0003) compared with healthy controls, whereas STAT5B was significantly downregulated (p = 0.0006). The expression of JAK1, JAK2, JAK3, and STAT5A did not differ significantly between groups.

CONCLUSIONS AND RELEVANCE

To the best of our knowledge, this is the first article reporting dysregulation of the JAK/STAT pathway in cholesteatoma-adjacent mucosa. The main finding is that important players of the aforementioned pathway are significantly altered, namely SOCS1 is upregulated and STAT5B is downregulated compared with healthy controls.

SOCS, SPRED, and NR4a: Negative regulators of cytokine signaling and transcription in immune tolerance

Cytokines are important intercellular communication tools for immunity. Most cytokines utilize the JAK-STAT and Ras-ERK pathways to promote gene transcription and proliferation; however, this signaling is tightly regulated. The suppressor of cytokine signaling (SOCS) family and SPRED family are a representative negative regulators of the JAK-STAT pathway and the Ras-ERK pathway, respectively. The SOCS family regulates the differentiation and function of CD4⁺ T cells, CD8⁺ T cells, and regulatory T cells, and is involved in immune tolerance, anergy, and exhaustion. SPRED family proteins have been shown to inactivate Ras by recruiting the Ras-GTPase neurofibromatosis type 1 (NF1) protein. Human genetic analysis has shown that SOCS family members are strongly associated with autoimmune diseases, allergies, and tumorigenesis, and SPRED1 is involved in NF1-like syndromes and tumors. We also identified the NR4a family of nuclear receptors as a key transcription factor for immune tolerance that suppresses cytokine expression and induces various immuno-regulatory molecules including SOCS1.

SOCS3-microtubule interaction via CLIP-170 and CLASP2 is critical for modulation of endothelial inflammation and lung injury

Proinflammatory cytokines such as IL-6 induce endothelial cell (EC) barrier disruption and trigger an inflammatory response in part by activating the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway. The protein suppressor of cytokine signaling-3 (SOCS3) is a negative regulator of JAK-STAT, but its role in modulation of lung EC barrier dysfunction caused by bacterial pathogens has not been investigated. Using human lung ECs and EC-specific SOCS3 knockout mice, we tested the hypothesis that SOCS3 confers microtubule (MT)-mediated protection against endothelial dysfunction. SOCS3 knockdown in cultured ECs or EC-specific SOCS3 knockout in mice resulted in exacerbated lung injury characterized by increased permeability and inflammation in response to IL-6 or heat-killed Staphylococcus aureus (HKSA). Ectopic expression of SOCS3 attenuated HKSA-induced EC dysfunction, and this effect required assembled MTs. SOCS3 was enriched in the MT fractions, and treatment with HKSA disrupted SOCS3-MT association. We discovered that-in addition to its known partners gp130 and JAK2-SOCS3 interacts with MT plus-end binding proteins CLIP-170 and CLASP2 via its N-terminal domain. The resulting SOCS3-CLIP-170/CLASP2 complex was essential for maximal SOCS3 anti-inflammatory effects. Both IL-6 and HKSA promoted MT disassembly and disrupted SOCS3 interaction with CLIP-170 and CLASP2. Moreover, knockdown of CLIP-170 or CLASP2 impaired SOCS3-JAK2 interaction and abolished the anti-inflammatory effects of SOCS3. Together, these findings demonstrate for the first time an interaction between SOCS3 and CLIP-170/CLASP2 and reveal that this interaction is essential to the protective effects of SOCS3 in lung endothelium.

MicroRNA-140-5p regulates the proliferation, apoptosis and inflammation of RA FLSs by repressing STAT3

Ectopic expression of microRNA (miRNA) in rheumatoid arthritis (RA) fibroblast-like synoviocyte (RA FLS) is associated with the development of rheumatoid arthritis. The present study aimed to evaluate the effects of miRNA-140-5p (miR-140) on the properties of RA FLSs. It was found that miR-140 expression was decreased in 33 RA patients and extracted RA FLS samples, when compared to the corresponding healthy controls. Abnormally increased miR-140 expression in RA FLSs attenuated cell proliferation and increased cell apoptosis. Additionally, reduced pro-inflammatory cytokine production was observed in RA FLSs transfected with a miR-140 precursor. Furthermore, the 3'-UTR of the signal transducer and activator of transcription (STAT) 3 gene was identified as a target of miR-140. Notably, restoration of STAT3 expression rescued the regulatory effect of miR-140 on the proliferation, apoptosis and inflammatory cytokine production of RA FLSs. Therefore, the current findings indicated that miR-140 is a crucial modulator of both proliferation and apoptosis, shedding light on the etiology behind RA FLS viability, which is modulated by an interplay between miR-140 and STAT3 in the context of RA.

Genome-wide translation patterns in gliomas: An integrative view

Gliomas are the most frequent tumors of the central nervous system (CNS) and include the highly malignant glioblastoma (GBM). Characteristically, gliomas have translational control deregulation related to overactivation of signaling pathways such as PI3K/AKT/mTORC1 and Ras/ERK1/2. Thus, mRNA translation appears to play a dominant role in glioma gene expression patterns. The, analysis of genome-wide translated transcripts, together known as the translatome, may reveal important information for understanding gene expression patterns in gliomas. This review provides a brief overview of translational control mechanisms altered in gliomas with a focus on the current knowledge related to the translatomes of glioma cells and murine glioma models. We present an integrative meta-analysis of selected glioma translatome data with the aim of identifying recurrent patterns of gene expression preferentially regulated at the level of translation and obtaining clues regarding the pathological significance of these alterations. Re-analysis of several translatome datasets was performed to compare the translatomes of glioma models with those of their non-tumor counterparts and to document glioma cell responses to radiotherapy and MNK modulation. The role of recurrently altered genes in the context of translational control and tumorigenesis are discussed.

Accelerator or Brake: Immune Regulators in Malaria

Malaria is a life-threatening infectious disease, affecting over 250 million individuals worldwide each year, eradicating malaria has been one of the greatest challenges to public health for a century. Growing resistance to anti-parasitic therapies and lack of effective vaccines are major contributing factors in controlling this disease. However, the incomplete understanding of parasite interactions with host anti-malaria immunity hinders vaccine development efforts to date. Recent studies have been unveiling the complexity of immune responses and regulators against Plasmodium infection. Here, we summarize our current understanding of host immune responses against Plasmodium-derived components infection and mainly focus on the various regulatory mechanisms mediated by recent identified immune regulators orchestrating anti-malaria immunity.

CDK8 Fine-Tunes IL-6 Transcriptional Activities by Limiting STAT3 Resident Time at the Gene Loci

Cytokines are highly pleiotropic ligands that regulate the immune response. Here, using interleukin-6 (IL-6) as a model system, we perform detailed phosphoproteomic and transcriptomic studies in human CD4⁺ T helper 1 (Th-1) cells to address the molecular bases defining cytokine functional pleiotropy. We identify CDK8 as a negative regulator of STAT3 transcriptional activities, which interacts with STAT3 upon IL-6 stimulation. Inhibition of CDK8 activity, using specific small molecule inhibitors, reduces the IL-6-induced phosphoproteome by 23% in Th-1 cells, including STAT3 S727 phosphorylation. STAT3 binding to target DNA sites in the genome is increased upon CDK8 inhibition, which results in a concomitant increase in STAT3-mediated transcriptional activity. Importantly, inhibition of CDK8 activity under Th-17 polarizing conditions results in an enhancement of Th-17 differentiation. Our results support a model where CDK8 regulates STAT3 transcriptional processivity by modulation of its gene loci resident time, critically contributing to diversification of IL-6 responses.

•

CDK8 regulates IL-6-mediated STAT3 S727 phosphorylation in primary human T cells

•

CDK8 controls STAT3 activity by limiting its resident time at gene loci

•

CDK8 inhibition increases IL-6-mediated Th17 differentiation

N6-Adenosine Methylation of Socs1 mRNA Is Required to Sustain the Negative Feedback Control of Macrophage Activation

Bacterial infection triggers a cytokine storm that needs to be resolved to maintain the host's wellbeing. Here, we report that ablation of m⁶A methyltransferase subunit METTL14 in myeloid cells exacerbates macrophage responses to acute bacterial infection in mice, leading to high mortality due to sustained production of pro-inflammatory cytokines. METTL14 depletion blunts Socs1 m⁶A methylation and reduces YTHDF1 binding to the m⁶A sites, which diminishes SOCS1 induction leading to the overactivation of TLR4/NF-κB signaling. Forced expression of SOCS1 in macrophages depleted of METTL14 or YTHDF1 rescues the hyper-responsive phenotype of these macrophages in vitro and in vivo. We further show that LPS treatment induces Socs1 m⁶A methylation and sustains SOCS1 induction by promoting Fto mRNA degradation, and forced FTO expression in macrophages mimics the phenotype of METTL14-depleted macrophages. We conclude that m⁶A methylation-mediated SOCS1 induction is required to maintain the negative feedback control of macrophage activation in response to bacterial infection.

Growth Hormone Receptor Regulation in Cancer and Chronic Diseases

The GHR signaling pathway plays important roles in growth, metabolism, cell cycle control, immunity, homeostatic processes, and chemoresistance via both the JAK/STAT and the SRC pathways. Dysregulation of GHR signaling is associated with various diseases and chronic conditions such as acromegaly, cancer, aging, metabolic disease, fibroses, inflammation and autoimmunity. Numerous studies entailing the GHR signaling pathway have been conducted for various cancers. Diverse factors mediate the up- or down-regulation of GHR signaling through post-translational modifications. Of the numerous modifications, ubiquitination and deubiquitination are prominent events. Ubiquitination by E3 ligase attaches ubiquitins to target proteins and induces proteasomal degradation or starts the sequence of events that leads to endocytosis and lysosomal degradation. In this review, we discuss the role of first line effectors that act directly on the GHR at the cell surface including ADAM17, JAK2, SRC family member Lyn, Ubc13/CHIP, proteasome, βTrCP, CK2, STAT5b, and SOCS2. Activity of all, except JAK2, Lyn and STAT5b, counteract GHR signaling. Loss of their function increases the GH-induced signaling in favor of aging and certain chronic diseases, exemplified by increased lung cancer risk in case of a mutation in the SOCS2-GHR interaction site. Insight in their roles in GHR signaling can be applied for cancer and other therapeutic strategies.

Walnut polyphenol extracts inhibit Helicobacter pylori-induced STAT3Tyr705 phosphorylation through activation of PPAR-γ and SOCS1 induction

The health beneficial effects of walnut plentiful of n-3 polyunsaturated fatty acid had been attributed to its anti-inflammatory and anti-oxidative properties against various clinical diseases. Since we have published Fat-1 transgenic mice overexpressing 3-desaturase significantly mitigated Helicobacter pylori (H. pylori)-associated gastric pathologies including rejuvenation of chronic atrophic gastritis and prevention of gastric cancer, in this study, we have explored the underlying molecular mechanisms of walnut against H. pylori infection. Fresh walnut polyphenol extracts (WPE) were found to suppress the phosphorylation and nuclear translocation of signal transducer and activator of transcription 3 (STAT3) induced by H. pylori infection in RGM-1 gastric mucosal cells. Notably, H. pylori infection significantly decreased suppressor of cytokine signaling 1 (SOCS1), but WPE induced expression of SOCS1, by which the suppressive effect of walnut extracts on STAT3^Tyr705 phosphorylation was not seen in SOCS1 KO cells. WPE induced significantly increased nuclear translocation nuclear translocation of PPAR-γ in RGM1 cells, by which PPAR-γ KO inhibited transcription of SOCS1 and suppressive effect of WPE on p-STAT3^Tyr705 was not seen. WPE inhibited the expression of c-Myc and IL-6/IL-6R signaling, which was attenuated in the RGM1 cells harboring SOCS1 specific siRNA. Conclusively, WPE inhibits H. pylori-induced STAT3 phosphorylation in a PPAR-γ and SOCS1-dependent manner.

SOCS Proteins Participate in the Regulation of Innate Immune Response Caused by Viruses

The host immune system has multiple innate immune receptors that can identify, distinguish and react to viral infections. In innate immune response, the host recognizes pathogen-associated molecular patterns (PAMP) in nucleic acids or viral proteins through pathogen recognition receptors (PRRs), especially toll-like receptors (TLRs) and induces immune cells or infected cells to produce type I Interferons (IFN-I) and pro-inflammatory cytokines, thus when the virus invades the host, innate immunity is the earliest immune mechanism. Besides, cytokine-mediated cell communication is necessary for the proper regulation of immune responses. Therefore, the appropriate activation of innate immunity is necessary for the normal life activities of cells. The suppressor of the cytokine signaling proteins (SOCS) family is one of the main regulators of the innate immune response induced by microbial pathogens. They mainly participate in the negative feedback regulation of cytokine signal transduction through Janus kinase signal transducer and transcriptional activator (JAK/STAT) and other signal pathways. Taken together, this paper reviews the SOCS proteins structures and the function of each domain, as well as the latest knowledge of the role of SOCS proteins in innate immune caused by viral infections and the mechanisms by which SOCS proteins assist viruses to escape host innate immunity. Finally, we discuss potential values of these proteins in future targeted therapies.

Functional genomic landscape of cancer-intrinsic evasion of killing by T cells

The genetic circuits that allow cancer cells to evade destruction by the host immune system remain poorly understood^1-3. Here, to identify a phenotypically robust core set of genes and pathways that enable cancer cells to evade killing mediated by cytotoxic T lymphocytes (CTLs), we performed genome-wide CRISPR screens across a panel of genetically diverse mouse cancer cell lines that were cultured in the presence of CTLs. We identify a core set of 182 genes across these mouse cancer models, the individual perturbation of which increases either the sensitivity or the resistance of cancer cells to CTL-mediated toxicity. Systematic exploration of our dataset using genetic co-similarity reveals the hierarchical and coordinated manner in which genes and pathways act in cancer cells to orchestrate their evasion of CTLs, and shows that discrete functional modules that control the interferon response and tumour necrosis factor (TNF)-induced cytotoxicity are dominant sub-phenotypes. Our data establish a central role for genes that were previously identified as negative regulators of the type-II interferon response (for example, Ptpn2, Socs1 and Adar1) in mediating CTL evasion, and show that the lipid-droplet-related gene Fitm2 is required for maintaining cell fitness after exposure to interferon-γ (IFNγ). In addition, we identify the autophagy pathway as a conserved mediator of the evasion of CTLs by cancer cells, and show that this pathway is required to resist cytotoxicity induced by the cytokines IFNγ and TNF. Through the mapping of cytokine- and CTL-based genetic interactions, together with in vivo CRISPR screens, we show how the pleiotropic effects of autophagy control cancer-cell-intrinsic evasion of killing by CTLs and we highlight the importance of these effects within the tumour microenvironment. Collectively, these data expand our knowledge of the genetic circuits that are involved in the evasion of the immune system by cancer cells, and highlight genetic interactions that contribute to phenotypes associated with escape from killing by CTLs.

Molecular evolution and functional characterization of SOCS3a and SOCS3b in miiuy croaker (Miichthys miiuy)

The suppressor of cytokine signaling 3 (SOCS3), as a negative regulator in inferferon (IFN) signaling pathways in mammals, has a vital role in immune systems. However, studies on the function of SOCS3 in lower vertebrates are limited. In this study, we identified SOCS3a and fish-specific SOCS3b gene in miiuy croaker. Sequence analysis results showed that SOCS3a and SOCS3b were evolutionarily conservative in fish. Expression analysis indicated that miiuy croaker SOCS3a and SOCS3b (mmSOCS3a and mmSOCS3b) were expressed in all of the tested miiuy croaker tissues, thus revealing the potential ability to perceive poly (I:C) stimulation. Further functional experiments showed that mmSOCS3a and mmSOCS3b could inhibit the IFNγ- and IFNα-induced ISRE reporter activation, respectively. Accordingly, the investigation of mmSOCS3a and mmSOCS3b can provide insights into fish SOCS3 and a basis for future research on the SOCS family of fish immune systems.

Differential regulation of JAK/STAT-signaling in patients with ulcerative colitis and Crohn’s disease

In 2018, the pan-Janus kinase (JAK) inhibitor tofacitinib was launched for the treatment of ulcerative colitis (UC). Although tofacitinib has proven efficacious in patients with active UC, it failed in patients with Crohn’s disease (CD). This finding strongly hints at a different contribution of JAK signaling in both entities. Here, we review the current knowledge on the interplay between the JAK/signal transducer and activator of transcription (STAT) pathway and inflammatory bowel diseases (IBD). In particular, we provide a detailed overview of the differences and similarities of JAK/STAT-signaling in UC and CD, highlight the impact of the JAK/STAT pathway in experimental colitis models and summarize the published evidence on JAK/STAT-signaling in immune cells of IBD as well as the genetic association between the JAK/STAT pathway and IBD. Finally, we describe novel treatment strategies targeting JAK/STAT inhibition in UC and CD and comment on the limitations and challenges of the new drug class.

Structural Understanding of Interleukin 6 Family Cytokine Signaling and Targeted Therapies: Focus on Interleukin 11

Cytokines are small signaling proteins that have central roles in inflammation and cell survival. In the half-century since the discovery of the first cytokines, the interferons, over fifty cytokines have been identified. Amongst these is interleukin (IL)-6, the first and prototypical member of the IL-6 family of cytokines, nearly all of which utilize the common signaling receptor, gp130. In the last decade, there have been numerous advances in our understanding of the structural mechanisms of IL-6 family signaling, particularly for IL-6 itself. However, our understanding of the detailed structural mechanisms underlying signaling by most IL-6 family members remains limited. With the emergence of new roles for IL-6 family cytokines in disease and, in particular, roles of IL-11 in cardiovascular disease, lung disease, and cancer, there is an emerging need to develop therapeutics that can progress to clinical use. Here we outline our current knowledge of the structural mechanism of signaling by the IL-6 family of cytokines. We discuss how this knowledge allows us to understand the mechanism of action of currently available inhibitors targeting IL-6 family cytokine signaling, and most importantly how it allows for improved opportunities to pharmacologically disrupt cytokine signaling. We focus specifically on the need to develop and understand inhibitors that disrupt IL-11 signaling.

BC-Box Motif in SOCS6 Induces Differentiation of Epidermal Stem Cells into GABAnergic Neurons

The BC-box motif in suppressor of cytokine signaling 6 (SOCS6) promotes the neuronal differentiation of somatic stem cells, including epidermal stem cells. SOCS6 protein belongs to the group of SOCS proteins and inhibits cytokine signaling. Here we showed that epidermal stem cells were induced to differentiate into GABAnergic neurons by the intracellular delivery of a peptide composed of the amino-acid sequences encoded by the BC-box motif in SOCS6 protein. The BC-box motif (SLQYLCRFVI) in SOCS6 corresponded to the binding site of elongin BC. GABAnergic differentiation mediated by the BC-box motif in SOCS6 protein was caused by ubiquitination of JAK2 and inhibition of the JAK2-STAT3 pathway. Furthermore, GABAnergic neuron-like cells generated from epidermal stem cells were transplanted into the brain of a rodent ischemic model. Then, we demonstrated that these transplanted cells were GAD positive and that the cognitive function of the ischemic model rodents with the transplanted cells was improved. This study could contribute to not only elucidating the mechanism of GABAnergic neuronal differentiation but also to neuronal regenerative medicine utilizing GABAnergic neurons.

Deletion of IL-6 Exacerbates Colitis and Induces Systemic Inflammation in IL-10-Deficient Mice

BACKGROUND AND AIMS

Interleukin 6 [IL-6] or its receptor is currently a candidate for targeted biological therapy of inflammatory bowel disease [IBD]. Thus, a comprehensive understanding of the consequences of blocking IL-6 is imperative. We investigated this by evaluating the effects of IL-6 deletion on the spontaneous colitis of IL-10-deficient mice [IL-10-/-].

METHODS

IL-6/IL-10 double-deficient mice [IL-6-/-/IL-10-/-] were generated and analysed for intestinal inflammation, general phenotypes and molecular/biochemical changes in the colonic mucosa compared with wild-type and IL-10-/- mice.

RESULTS

Unexpectedly, the IL-6-/-/IL-10-/- mice showed more pronounced gut inflammation and earlier disease onset than IL-10-/- mice, both locally [colon and small bowel] and systemically [splenomegaly, ulcerative dermatitis, leukocytosis, neutrophilia and monocytosis]. IL-6-/-/IL-10-/- mice exhibited elevations of multiple cytokines [IL-1β, IL-4, IL-12, TNFα] and chemokines [MCP-1 and MIG], but not IFN-γ [Th1], IL-17A and IL-17G [Th17], or IL-22 [Th22]. FOXP3 and TGF-β, two key factors for regulatory T [Treg] cell differentiation, were significantly down-regulated in the colonic mucosa, but not in the thymus or mesenteric lymph nodes, of IL-6-/-/IL-10-/- mice. CTLA-4 was diminished while iNOS was up-regulated in the colonic mucosa of IL-6-/-/IL-10-/- mice.

CONCLUSION

In IL-10-/- mice, complete IL-6 blockade significantly aggravates gut inflammation, at least in part by suppressing Treg/CTLA-4 and promoting the IL-1β/Th2 pathway. In addition, the double mutant exhibits signs of severe systemic inflammation. Our data define a new function of IL-6 and suggest that caution should be exercised when targeting IL-6 in IBD patients, particularly those with defects in IL-10 signalling.

Genome-Wide CRISPR-Cas9 Screens Expose Genetic Vulnerabilities and Mechanisms of Temozolomide Sensitivity in Glioblastoma Stem Cells

Glioblastoma therapies have remained elusive due to limitations in understanding mechanisms of growth and survival of the tumorigenic population. Using CRISPR-Cas9 approaches in patient-derived GBM stem cells (GSCs) to interrogate function of the coding genome, we identify actionable pathways responsible for growth, which reveal the gene-essential circuitry of GBM stemness and proliferation. In particular, we characterize members of the SOX transcription factor family, SOCS3, USP8, and DOT1L, and protein ufmylation as important for GSC growth. Additionally, we reveal mechanisms of temozolomide resistance that could lead to combination strategies. By reaching beyond static genome analysis of bulk tumors, with a genome-wide functional approach, we reveal genetic dependencies within a broad range of biological processes to provide increased understanding of GBM growth and treatment resistance.

The methylation status of TNF-α and SOCS3 promoters and the regulation of these gene expressions in patients with Behçet's disease

Introduction: The aim of this study was to evaluate the methylation status of TNF-α and SOCS3 promoters in patients with BD and compare them with a healthy group.Method: This was a case-control study, in which 47 subjects with BD and 61 individuals as the control participated. Blood samples were collected from all the participants. Then, PBMCs were isolated using the Ficoll method and methylation of considered sites was investigated using the qMS-PCR technique after DNA extraction by the rapid genomic DNA extraction method and its analysis with Nano-drop.Results: The methylation and expression of TNF-α showed that the methylation level significantly declined in the patient in comparison with the healthy (p < 0.05). Moreover, the results on the mean expression showed that it significantly increased in the patient group, as compared with the healthy group (p < 0.05). In addition, the expression of the SOCS3 gene was not significantly different between the patients and healthy subjects while the level of SOCS3 methylation was significantly higher in the patient group than that in the healthy group (p < 0.05).Discussion: The present study revealed that the gene expression of TNF-alpha increased in BD patients, suggesting that TNF-alpha likely has a role in the pathogenesis of BD.

EPAS1 regulates proliferation of erythroblasts in chronic mountain sickness

Excessive erythrocytosis (EE) is a characteristic of chronic mountain sickness (CMS). Currently, the pathogenesis of CMS remains unclear. This study was intended to investigate the role of EPAS1 in the proliferation of erythroblasts in CMS. Changes of HIF-1α and EPAS1/HIF-2α in the bone marrow erythroblasts of 21 patients with CMS and 14 control subjects residing at the same altitudes were determined by RT-qPCR and western blotting. We also developed a lentiviral vector, Lv-EPAS1/sh-EPAS1, to over-express/silence EPAS1 in K562 cells. Cells cycle and proliferation were detected by flow cytometry. Transcriptome analyses were carried out on Illumina. CMS patients showed a higher expression of EPAS1/HIF-2α in the bone marrow erythroblasts than those of controls. Variations in EPAS1 expression in CMS patients were positively correlated with RBC levels, and negatively correlated with SaO₂. Over-expressing of EPAS1 in K562 cells accelerated the erythroid cells cycle progression and promoted the erythroid cells proliferation-and vice versa. Transcriptome data indicated that proliferation-related DEGs were significantly enriched in EPAS1 overexpression/silencing K562 cells. Our results suggest that EPAS1 might participate in the pathogenesis of EE by regulating the proliferation of erythroblasts.

The Role of JAK-STAT Signaling Activation in Hypertrophied Ligamentum Flavum

BACKGROUND

Although previous studies have reported the expression of JAK1, STAT3, and phosphorylated STAT3 in hypertrophied ligamentum flavum (LF), the role of the Janus kinase-signal transducer and activator of transcription (JAK/STAT) signaling pathway in hypertrophied LF has not been fully elucidated. The aim of this study was to identify the important JAK/STAT gene expression patterns of the 3 main receptors involved in this pathway: interferon (IFN)-γ receptor (IFN-γR), IFN-α receptor (IFNAR), and interleukin (IL)-6 receptor (IL-6R).

METHODS

The human LF specimens were obtained from 28 patients who underwent lumbar spine surgery for either degenerative lumbar canal stenosis (DLCS) (n = 28) or lumbar disc herniation (LDH) (n = 20). In this design, patients with LDH served as the control group. The degree of fibrosis was demonstrated by Masson's trichrome staining. The location and expression profiling of the JAK/STAT pathway were analyzed by quantitative real-time polymerase chain reaction and Western blotting. The thickness of the LF was measured with axial T1-weighted magnetic resonance imaging.

RESULTS

The most severe fibrotic changes were on the dorsal side of the LF. IL-6 and IFN-I expression levels were significantly increased on the dorsal side of the LF. While expression levels of IL-6R and IFNAR on the dural and dorsal side were significantly higher in the DLCS samples, IFN-γR and endothelial epidermal growth factor receptor in LF samples showed a significant increase only on the dorsal side. JAK/STAT genes were significantly expressed, especially on the dorsal side.

CONCLUSIONS

Our data suggest that IFNAR- and IL-6R-dependent JAK/STAT signaling pathways may be significant targets in drug development strategies for the treatment of LF hypertrophy.

SOCS3 Attenuates GM-CSF/IFN-γ-Mediated Inflammation During Spontaneous Spinal Cord Regeneration

SOCS3, a feedback inhibitor of the JAK/STAT signal pathway, negatively regulates axonal regrowth and inflammation in the central nervous system (CNS). Here, we demonstrated a distinct role of SOCS3 in the injured spinal cord of the gecko following tail amputation. Severing the gecko spinal cord did not evoke an inflammatory cascade except for an injury-stimulated elevation of the granulocyte/macrophage colony-stimulating factor (GM-CSF) and interferon gamma (IFN-γ) cytokines. Simultaneously, the expression of SOCS3 was upregulated in microglia, and unexpectedly not in neurons. Enforced expression of SOCS3 was sufficient to suppress the GM-CSF/IFN-γ-driven inflammatory responses through its KIR domain by attenuating the activities of JAK1 and JAK2. SOCS3 was also linked to GM-CSF/IFN-γ-induced cross-tolerance. Transfection of adenovirus overexpressing SOCS3 in the injured cord resulted in a significant decrease of inflammatory cytokines. These results reveal a distinct role of SOCS3 in the regenerating spinal cord, and provide new hints for CNS repair in mammals.

Mammary epithelial cell derived exosomal MiR-221 mediates M1 macrophage polarization via SOCS1/STATs to promote inflammatory response

Lactational mastitis seriously alters the normal physiological function of mammary gland and activates the innate immune. Mammary epithelial cells (MECs) secret cytokines and regulate the function of immune system. However, the mechanism MECs mediated crosstalk with immune cells, such as macrophages, during mastitis is unclear. In this study, mouse mammary epithelial cells (HC11), treated with Lipoteichoic acid (LTA), and macrophages (RAW264.7) were used to mimic intercellular communication. Our results showed that exosomal miR-221 level was up-regulated and reached the peak at 12 h after infected by LTA. The expression of miR-211, CD11b protein and TNF-α mRNA were upregulated and the expression of CD206 protein and Arg-1 mRNA were inhibited in RAW264.7 treated with exosomes. In addition, miR-221 mimics and inhibitors enhanced and depressed HC11-derived exosomal miR-221 level, respectively. After treatment of Exo(mimic) in RAW264.7, the expression of CD11b protein and TNF-α mRNA were up-regulated, the expression of CD206 and Arg-1 mRNA were down-regulated. Additionally, Exo(inhibitor) enhanced CD206 protein and Arg-1 mRNA levels and inhibited CD11b protein and TNF-α mRNA levels. Furthermore, SOCS1 was identified to be a target gene of miR-221 by using Luciferase assays. And western blot assays showed that the expression of p-STAT1 and p-STAT3 were elevated and repressed, respectively. Taken together, we suggest that exosomal miR-221 promotes polarization of M1 macrophages via SOCS1, STAT1 and STAT3. And we reveal a novel crosstalk signaling pathway between mammary epithelial cells and macrophages in the process of inflammation.

Function and Modulation of Type I Interferons during Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory infections in infants and young children, accounting for an estimated 3 million hospitalizations annually worldwide. Despite the major health burden, there is currently no licensed RSV vaccine. RSV is recognized by a range of cellular receptors including both toll-like receptors (TLR) and retinoic acid-inducible gene-I-like receptors (RIG-I). This interaction initiates signaling through mitochondrial antiviral signaling (MAVS) and interferon regulatory factor (IRF) proteins, resulting in the induction of type I interferons (IFN). Early viral control is mediated by either IFN-α or IFN-β signaling through the IFN receptor (IFNAR), inducing the production of antiviral interferon-stimulating genes (ISGs). Type I IFNs also initiate the early production of proinflammatory cytokines including interleukin 6 (IL-6), tumor necrosis factor (TNF), and IFN-γ. Type I IFN levels correlate with age, and inadequate production may be a critical factor in facilitating the increased RSV disease severity observed in infants. Here, we review the current literature on the function of type I IFNs in RSV pathogenesis, as well as their involvement in the differential immune responses observed in infants and adults.

Ascorbate protects liver from metabolic disorder through inhibition of lipogenesis and suppressor of cytokine signaling 3 (SOCS3)

Background

Fatty liver is a reversible status, but also an origin stage to develop to other metabolic syndromes, such as diabetes and heart disease that threatens public health worldwide. Ascorbate deficiency is reported to be correlated with increasing risks for metabolic syndromes, but whether ascorbate has a therapeutic effect is unknown. Here, we investigated if ascorbate treatment alone could work on protecting from the development of steatosis and mechanisms beyond.

Methods

Guinea pigs were fed with a chow diet or a high palm oil diet (HPD) respectively. HPD induced animals were administered different concentrations of ascorbate in different time intervals through water. Besides, hepatocyte-like cells derived from human embryonic stem cells and HepG2 cells were treated with palmitic acid (PA) to induce lipid accumulation for molecular mechanism study.

Results

We find that ascorbate rescues HPD and PA induced steatosis and insulin tolerance in vivo and in vitro. We demonstrate that ascorbate changes cellular lipid profiles via inhibits lipogenesis, and inhibits the expression of SOCS3 via STAT3, thus enhances insulin signal transduction. Overexpression of SOCS3 abolishes the ascorbate rescue effects on insulin signal and lipid accumulation in hepatic cells.

Conclusions

Ascorbate ameliorates hepatic steatosis and improves insulin sensitivity through inhibiting lipogenesis and SOCS3.

Suppressors of cytokine signaling proteins as modulators of development and innate immunity of insects

The suppressors of cytokine signaling (SOCS) are a family of intracellular molecules. Many members of this family have been reported to be involved in various physiological processes in invertebrates and vertebrates (e.g., developmental process and immune response). The functions of SOCS molecules seem to remain conserved in animals throughout evolutionary history. The members of the SOCS family play vital roles in the physiological processes by regulating the extent and duration of signaling activities of both Janus Kinase-Signal Transducer and Activators of Transcription (JAK-STAT) and epidermal growth factor receptor (EGFR) pathways in vivo. So far, in different insect species, a variable number of SOCS and SOCS box domain-containing proteins have been identified. These proteins are categorized into different types based on their sequence diversification, leading to an alteration in structure and regulatory function. The biological roles of the many SOCS proteins have been established as a negative or positive regulator of the signaling pathways, as mentioned earlier. Here, we discussed the existing knowledge on the SOCS proteins and their involvement in different biological functions in insects, and future perspectives to further elucidate their physiological roles.

Targeting STAT-3 signaling pathway in cancer for development of novel drugs: Advancements and challenges

Signal transducers and activators of transcription 3 (STAT-3) is a transcription factor that regulates the gene expression of several target genes. These factors are activated by the binding of cytokines and growth factors with STAT-3 specific receptors on cell membrane. Few years ago, STAT-3 was considered an acute phase response element having several cellular functions such as inflammation, cell survival, invasion, metastasis and proliferation, genetic alteration, and angiogenesis. STAT-3 is activated by several types of inflammatory cytokines, carcinogens, viruses, growth factors, and oncogenes. Thus, the STAT3 pathway is a potential target for cancer therapeutics. Abnormal STAT-3 activity in tumor development and cellular transformation can be targeted by several genomic and pharmacological methodologies. An extensive review of the literature has been conducted to emphasize the role of STAT-3 as a unique cancer drug target. This review article discusses in detail the wide range of STAT-3 inhibitors that show antitumor effects both in vitro and in vivo. Thus, targeting constitutive STAT-3 signaling is a remarkable therapeutic methodology for tumor progression. Finally, current limitations, trials and future perspectives of STAT-3 inhibitors are also critically discussed.

Antihyperglycemic Effects and Mode of Actions of Musa paradisiaca Leaf and Fruit Peel Hydroethanolic Extracts in Nicotinamide/Streptozotocin-Induced Diabetic Rats

The present study aimed to evaluate the antihyperglycemic effects of Musa paradisiaca (M. paradisiaca) leaf and fruit peel hydroethanolic extracts and to suggest their probable mode of actions in nicotinamide (NA)/streptozotocin (STZ)-induced diabetic rats. The leaf and fruit peel hydroethanolic extracts were analyzed by GC-MS that indicated the presence of phytol, octadecatrienoic acid, hexadecanoic acid, and octadecadienoic acid as major components in the leaf extract and vitamin E, octadecenamide, β-sitosterol, and stigmasterol as major phytochemicals in the fruit peel extract. Diabetes mellitus was induced by a single intraperitoneal injection of STZ (60 mg/kg body weight) dissolved in citrate buffer (pH 4.5), 15 minutes after intraperitoneal injection of NA (120 mg/kg body weight). The NA/STZ-induced diabetic rats were, respectively, treated with M. paradisiaca leaf and fruit peel hydroethanolic extracts at a dose of 100 mg/kg body weight/day by oral administration for 28 days. The treatment of NA/STZ-induced diabetic rats with leaf and fruit peel extracts significantly improved the impaired oral glucose tolerance and significantly increased the lowered serum insulin and C-peptide levels. The HOMA-IR (as the index of insulin resistance) and QUICKI (as a marker for insulin sensitivity), as well as HOMA-β cell function were significantly alleviated as a result of treatment of diabetic rats with leaf and fruit peel extracts. In association, the elevated serum-free fatty acids, TNF-α, and IL-6 levels were significantly decreased. In addition, the suppressed adipose tissue PPARγ, GLUT4, adiponectin, and insulin receptor β-subunit mRNA expressions were upregulated while the elevated adipose tissue resistin expression was downregulated in diabetic rats as a result of treatment with the leaf and peel extract. Based on these results, it can be concluded that M. paradisiaca leaf and fruit peel hydroethanolic extracts have antihyperglycemic effects which may be mediated via their insulinotropic and insulin-sensitizing effects.

The role of JAK/STAT signaling pathway and its inhibitors in diseases

The JAK/STAT signaling pathway is an universally expressed intracellular signal transduction pathway and involved in many crucial biological processes, including cell proliferation, differentiation, apoptosis, and immune regulation. It provides a direct mechanism for extracellular factors-regulated gene expression. Current researches on this pathway have been focusing on the inflammatory and neoplastic diseases and related drug. The mechanism of JAK/STAT signaling is relatively simple. However, the biological consequences of the pathway are complicated due to its crosstalk with other signaling pathways. In addition, there is increasing evidence indicates that the persistent activation of JAK/STAT signaling pathway is closely related to many immune and inflammatory diseases, yet the specific mechanism remains unclear. Therefore, it is necessary to study the detailed mechanisms of JAK/STAT signaling in disease formation to provide critical reference for clinical treatments of the diseases. In this review, we focus on the structure of JAKs and STATs, the JAK/STAT signaling pathway and its negative regulators, the associated diseases, and the JAK inhibitors for the clinical therapy.

Human Monocytes/Macrophage Inflammatory Cytokine Changes Following in vivo and in vitro Schistomam manoni Infection

Introduction

Epidemiological and animal studies indicate that helminth infections have positive effects due to their potential to protect against autoimmune diseases. Here, we aim to assess the effect of S. mansoni infection on immune modulation of human monocytes and their potential protection against autoimmune disease development both in vivo and in vitro.

Materials and Methods

Monocytes were isolated from helminth-infected Ethiopians (MHIE), and from Dutch healthy volunteers (MHV). The MHV were stimulated in vitro with S. mansoni soluble egg antigens (SEA) or soluble worm antigens (SWA). In addition, phenotypical changes were studied directly, as well as after culturing for 6 days in the presence of human serum to obtain macrophages. Q-PCR, flow cytometry, multiplex bead immunoassay, and live-cell imaging were employed during analysis.

Results

MHIE showed elevated transcripts of SOCS-1 and TNF-α compared to MHV. Similarly, MHV that were stimulated with SEA demonstrated enhanced levels of SOCS-1, IL-10, and IL-12 mRNA, compared to control MHV. Remarkably, the SEA-treated monocytes showed a much higher motility than control monocytes, a hallmark of a patrolling phenotype. Furthermore, in vitro cultured macrophages that were stimulated by SEA exhibited enhanced mRNA levels of SOCS-1, IL-10, TNF-α, IL-12 and TGF-β, compared to control macrophages.

Conclusion

Macrophages from MHIE as well as SEA-treated MHV show an intermediate activation phenotype with both pro-inflammatory and anti-inflammatory characteristics in vitro. The observed pro-inflammatory properties might reflect a recent response of the cells due to contact with a pathogen, whereas the anti-inflammatory properties might contribute to helminth-induced protection against inflammatory diseases. Large-scale study is recommended to consolidate the findings of the present study.

Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use:

https://youtu.be/SYOVExqwTRU

Fruit and vegetable intake modifies the associations between suppressor of cytokine signaling 3 genetic variants and type 2 diabetes

PURPOSE

Type 2 diabetes is a complex disease determined by variable genes and environmental factors. The study was designed to investigate the effect of interactions of four polymorphisms of suppressor of cytokine signaling 3 (SOCS3) with fruit and vegetable (F&V) intake on type 2 diabetes in a rural population of China.

METHODS

A total of 4411 participants from the rural areas of Henan, China were included in the study. Multivariate logistic regression and restricted cubic splines were used to estimate the associations between polymorphisms and risk allele score of SOCS3 and type 2 diabetes in different groups. Haplotype analysis was conducted to examine the effects of linkage inheritance at these four loci on type 2 diabetes.

RESULTS

Three of the four polymorphisms showed significant associations with type 2 diabetes in the less F&V intake group after adjusting the covariates, the odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs) were 1.24 (1.08-1.41) for rs4969168, 1.16 (1.02-1.32) for rs9892622, and 1.21 (1.06-1.39) for rs9914220. No significant association was detected in the more F&V intake group. The obvious dose-response relationship between the risk allele score and type 2 diabetes was also noted only in the less F&V intake group.

CONCLUSIONS

Variants of SOCS3 gene were associated with type 2 diabetes and the associations could be modified by the F&V intake.

Effects of miR-150-5p on the growth and SOCS1 expression of rheumatoid arthritis synovial fibroblasts

OBJECTIVE

miR-150-5p has been implicated in the regulation and onset of immune diseases. We investigated the effects of miR-150-5p on the functions of RA synovial fibroblasts (RASFs).

METHOD

The binding site between suppressor of cytokine signaling 1 (SOCS1) and miR-150-5p was analyzed using European Bioinformatics Institute database, and the 3' UTR of SOCS1 mRNA, including the binding site, was amplified and ligated to the 3'-end of LUC2 gene in the pmirGL0 dual-luciferase vector. The pmirGL0 vector and corresponding mimics were subsequently co-transfected into 293T cells to compare the relative fluorescence intensity of LUC2 between the miR-150-5p mimics and the negative control (NC) mimics groups. Further, the RASF cell line MH7A was transfected with miR-150-5p or NC mimics and subjected to flow cytometric analysis, cell counting kit-8 assay, western blot analysis, qPCR, and enzyme-linked immunosorbent (ELISA) assay 48 h after transfection.

RESULTS

miR-150-5p mimics resulted in a lower cell apoptotic rate and proportion of cells in the S phase. Using a dual-luciferase reporter gene assay, we then found that SOCS1 is a potential target of miR-150-5p. Compared with NC mimics, miR-150-5p mimics significantly decreased the protein and mRNA expression levels of SOCS1. ELISA assay showed that miR-150-5p mimics increased interleukin-6 level in the cell culture medium but did not influence tumor necrosis factor-alpha levels.

CONCLUSIONS

Overall, the growth-promoting effect of miR-150-5p on MH7A cells may be attributed to the miR-150-5p-induced degradation of SOCS1 mRNA, suggesting a potential therapeutic target for RA.Key Points• SOCS1 is a potential target of miR-150-5p.• miR-150-5p promoted the growth of RASF cell line MH7A.• miR-150-5p increased the secretion of IL-6 but did not significantly affect TNF-α levels in MH7A cells.

Differential expression of zinc transporters in functionally contrasting tissues involved in zinc homeostasis

Zinc homeostasis is maintained by 24 tissue-specific zinc transporters which include ZnTs (ZnT1-10), ZIPs (ZIP1-14), in addition to metallothionein (MT). Current study aimed the role of zinc transporters in maintaining the basal levels of zinc in functionally contrasting tissue specific THP-1 (monocyte), RD (muscle), and Saos-2 (bone) cells. Zinc transporters expression was assessed by qRT-PCR. The mRNA levels of ZnTs (ZnT5-7 & ZnT9), ZIPs (ZIP6-10, ZIP13-14), and MT were significantly (p < 0.05) higher in Saos-2 compared to THP-1 and RD. The present study suggests that distinct expression pattern of zinc transporters and metallothionein might be responsible for the differential zinc assimilation.

SOCS2 modulates adipose tissue inflammation and expansion in mice

INTRODUCTION

Obesity is usually triggered by a nutrient overload that favors adipocyte hypertrophy and increases the number of pro-inflammatory cells and mediators into adipose tissue. These mediators may be regulated by suppressors of cytokine signaling (SOCS), such as SOCS2, which is involved in the regulation of the inflammatory response of many diseases, but its role in obesity is not yet known. We aimed to investigate the role of SOCS2 in metabolic and inflammatory dysfunction induced by a high-refined carbohydrate-containing diet (HC).

MATERIAL AND METHODS

Male C57BL/6 wild type (WT) and SOCS2 deficient (SOCS2^-/-) mice were fed chow or an HC diet for 8 weeks.

RESULTS

In general, SOCS2 deficient mice, independent of the diet, showed higher adipose tissue mass compared with their WT counterparts that were associated with decreased lipogenesis rate in adipose tissue, lipolysis in adipocyte culture and energy expenditure. An anti-inflammatory profile was observed in adipose tissue of SOCS2^-/- by reduced secretion of cytokines, such as TNF and IL-6, and increased M2-like macrophages and regulatory T cells compared with WT mice. Also, SOCS2 deficiency reduced the differentiation/expansion of pro-inflammatory cells in the spleen but increased Th2 and Treg cells compared with their WT counterparts.

CONCLUSION

The SOCS2 protein is an important modulator of obesity that regulates the metabolic pathways related to adipocyte size. Additionally, SOCS2 is an inflammatory regulator that appears to be essential for controlling the release of cytokines and the differentiation/recruitment of cells into adipose tissue during the development of obesity.

Identification of Haptoglobin as a Readout of rhGH Therapy in GH Deficiency

BACKGROUND

GH deficiency (GHD) is characterized by a cluster of cardiovascular risk factors and subtle inflammation. We aimed to demonstrate, through a proteomic approach, molecules directly modulated by GHD and involved in the inflammatory state.

METHODS

Ten children with isolated GHD were studied before and after 1 year of treatment with rhGH and compared with 14 matched controls. A two-dimensional electrophoresis plasma proteomics analysis was performed at baseline and after GH treatment to identify the top molecules modulated by GH. In vitro studies on human hepatoma (HepG2) cells were performed to validate the data.

RESULTS

Twelve of 20 proteomic spots were predicted to be isoforms α and β of haptoglobin (Hp) and confirmed by liquid chromatography tandem mass spectrometry and Western immunoblot analyses. Hp levels were higher in patients with GHD than controls at baseline (P < 0.001) and were reduced following GH treatment (P < 0.01). In HepG2 cells, both GH and IGF-1 were able to downregulate IL-6-induced Hp secretion. Moreover, Hp secretion was restored in pegvisomant-treated HepG2 cells.

CONCLUSIONS

Hp is a molecule acting in the inflammatory state of GHD and a possible biomarker for GH treatment. Nevertheless, the contribution of other factors and the molecular pathways involved in the GH downregulation of Hp remain to be clearly defined.

Loss of adenomatous polyposis coli function renders intestinal epithelial cells resistant to the cytokine IL-22

Interleukin-22 (IL-22) is a critical immune defence cytokine that maintains intestinal homeostasis and promotes wound healing and tissue regeneration, which can support the growth of colorectal tumours. Mutations in the adenomatous polyposis coli gene (Apc) are a major driver of familial colorectal cancers (CRCs). How IL-22 contributes to APC-mediated tumorigenesis is poorly understood. To investigate IL-22 signalling in wild-type (WT) and APC-mutant cells, we performed RNA sequencing (RNAseq) of IL-22-treated murine small intestinal epithelial organoids. In WT epithelia, antimicrobial defence and cellular stress response pathways were most strongly induced by IL-22. Surprisingly, although IL-22 activates signal transducer and activator of transcription 3 (STAT3) in APC-mutant cells, STAT3 target genes were not induced. Our analyses revealed that ApcMin/Min cells are resistant to IL-22 due to reduced expression of the IL-22 receptor, and increased expression of inhibitors of STAT3, particularly histone deacetylases (HDACs). We further show that IL-22 increases DNA damage and genomic instability, which can accelerate cellular transition from heterozygosity (ApcMin/+) to homozygosity (ApcMin/Min) to drive tumour formation. Our data reveal an unexpected role for IL-22 in promoting early tumorigenesis while excluding a function for IL-22 in transformed epithelial cells.

Signatures of selection for resistance to Haemonchus contortus in sheep and goats

Background

Gastrointestinal nematode infection (GNI) is the most important disease affecting the small ruminant industry in U.S. The environmental conditions in the southern United States are ideal for the survival of the most pathogenic gastrointestinal nematode, Haemonchus contortus. Host genetic variation for resistance to H. contortus allows selective breeding for increased resistance of animals. This selection process increases the prevalence of particular alleles in sheep and goats and creates unique genetic patterns in the genome of these species. The aim of this study was to identify loci with divergent allelic frequencies in a candidate gene panel of 100 genes using two different approaches (frequentist and Bayesian) to estimate Fst outliers in three different breeds of sheep and goats exposed to H. contortus.

Results

Our results for sheep populations showed SNPs under selection in C3AR1, CSF3, SOCS2, NOS2, STAT5B, TGFB2 and IL2RA genes using frequentist and Bayesian approaches. For goats, SNPs in CD1D, ITGA9, IL12A, IL13RA1, CD86 and TGFB2 genes were under selection. Common signatures of selection in both species were observed in NOS2, TGFB2 and TLR4 genes. Directional selection was present in all SNPs evaluated in the present study.

Conclusions

A total of 13 SNPs within 7 genes of our candidate gene panel related to H. contortus exposure were identified under selection in sheep populations. For goats, 11 SNPs within 7 genes were identified under selection. Results from this study support the hypothesis that resistance to H. contortus is likely to be controlled by many loci. Shared signatures of selection related to mechanisms of immune protection against H. contortus infection in sheep and goats could be useful targets in breeding programs aimed to produce resistant animals with low FEC.

Autophagy and Its Relationship to Epithelial to Mesenchymal Transition: When Autophagy Inhibition for Cancer Therapy Turns Counterproductive

The manipulation of autophagy for cancer therapy has gained recent interest in clinical settings. Although inhibition of autophagy is currently being used in clinical trials for the treatment of several malignancies, autophagy has been shown to have diverse implications for normal cell homeostasis, cancer cell survival, and signaling to cells in the tumor microenvironment. Among these implications and of relevance for cancer therapy, the autophagic process is known to be involved in the regulation of protein secretion, in tumor cell immunogenicity, and in the regulation of epithelial-to-mesenchymal transition (EMT), a critical step in the process of cancer cell invasion. In this work, we have reviewed recent evidence linking autophagy to the regulation of EMT in cancer and normal epithelial cells, and have discussed important implications for the manipulation of autophagy during cancer therapy.