Phosphorylation Levels Of STAT1 Research Articles

Stigmasterol Exerts an Anti-Melanoma Property through Down-Regulation of Reactive Oxygen Species and Programmed Cell Death Ligand 1 in Melanoma Cells.

Cancer immunotherapy as a promising anti-cancer strategy has been widely studied in recent years. Stigmasterol (STIG), a phytosterol, is known to have various pharmacological effects, including anti-inflammatory effects. However, the pharmacological role of STIG on melanoma immunotherapy has not been investigated. The present study demonstrates the anti-melanoma potency of STIG through the regulation of PD-L1 levels. The results reveal that STIG reduces reactive oxygen species (ROS) levels induced by hydrogen peroxide and increases glutathione levels decreased by α-MSH in B16F10 cells. Moreover, STIG significantly decreases melanin content and tyrosinase activities elevated by α-MSH. It also suppresses nitric oxide production induced by α-MSH. Additionally, STIG induces apoptosis with the up-regulation of PARP activation. STIG inhibits IFN-γ-induced PD-L1 expression and STAT1 phosphorylation levels. STIG also reverses the up-regulation of PD-L1 and phosphorylated STAT1 levels augmented by cisplatin, and STIG enhances CD8(+) T-cell-mediated cell death against B16F10 cells. These findings represent the first evidence of pro-apoptotic activity of STIG on melanoma cells through the down-regulation of ROS and PD-L1 pathways. Therefore, STIG may be an effective candidate for melanoma immunotherapy.

UMP-CMP kinase 2 inhibits ZIKV replication through activation of type I IFN signaling pathway.

Cytidine/uridine monophosphate kinase 2 (UMP-CMP kinase 2, CMPK2) has been reported as an antiviral interferon-stimulated gene (ISG). We previously observed that the expression of CMPK2 was significantly upregulated after Zika Virus (ZIKV) infection in A549 cells. However, the association and the underlying mechanisms between CMPK2 induction and ZIKV replication remain to be determined. We investigated the induction of CMPK2 during ZIKV infection and the effect of CMPK2 on ZIKV replication in A549, U251, Vero, IFNAR-deficient U5A and its parental 2fTGH cells, Huh7 and its RIG-I-deficient derivatives Huh7.5.1 cells. The activation status of Jak-STAT signaling pathway was determined by detecting the phosphorylation level of STAT1, the activity of interferon stimulated response element (ISRE) and the expression of several interferon stimulated genes (ISGs). We found that ZIKV infection induced CMPK2 expression through an IFNAR and RIG-I dependent manner. Overexpression of CMPK2 inhibited while CMPK2 knockdown promoted ZIKV replication in A549 and U251 cells. Mechanically, we found that CMPK2 overexpression increased IFNβ expression and activated Jak/STAT signaling pathway as shown by the increased level of p-STAT1, enhanced activity of ISRE, and the upregulated expression of downstream ISGs. These findings suggest that ZIKV infection induced CMPK2 expression, which inhibited ZIKV replication and serves as a positive feedback regulator for IFN-Jak/STAT pathway.

Neointimal myofibroblasts contribute to maintaining Th1/Tc1 and Th17/Tc17 inflammation in giant cell arteritis

Vascular smooth muscle cells (VSMCs) have been shown to play a role in the pathogenesis of giant cell arteritis (GCA) through their capacity to produce chemokines recruiting T cells and monocytes in the arterial wall and their ability to migrate and proliferate in the neointima where they acquire a myofibroblast (MF) phenotype, leading to vascular stenosis. This study aimed to investigate if MFs could also impact T-cell polarization.Confocal microscopy was used to analyze fresh fragments of temporal artery biopsies (TABs). Healthy TAB sections were cultured to obtain MFs, which were then treated or not with interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) and analyzed by immunofluorescence and RT-PCR. After peripheral blood mononuclear cells and MFs were co-cultured for seven days, T-cell polarization was analyzed by flow cytometry.In the neointima of GCA arteries, we observed a phenotypic heterogeneity among VSMCs that was consistent with a MF phenotype (α-SMA+CD90+desmin+MYH11+) with a high level of STAT1 phosphorylation. Co-culture experiments showed that MFs sustain Th1/Tc1 and Th17/Tc17 polarizations. The increased Th1 and Tc1 polarization was further enhanced following the stimulation of MFs with IFN-γ and TNF-α, which induced STAT1 phosphorylation in MFs. These findings correlated with increases in the production of IL-1β, IL-6, IL-12 and IL-23 by MFs.Our study showed that MFs play an additional role in the pathogenesis of GCA through their ability to maintain Th17/Tc17 and Th1/Tc1 polarizations, the latter being further enhanced in case of stimulation of MF with IFN-γ and TNF-α.

All-Trans-Retinoic Acid Induction Overcomes Immune Evasion through Downregulating Immune Checkpoint Molecules and Inducing a Cytokine Storm Triggered By Overexpression of S100A8/A9 Signaling

Background: More than 95% of acute promyelocytic leukemia (APL) patients can achieve complete remission by dual induction of all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO). However, early death is a treatment obstacle of APL. The main causes of early death in APL include hemorrhage, differentiation syndrome (DS) related to induction therapy, and infection. Currently, the mechanism of DS in APL largely remains unclear. This study aims to investigate the pathogenetic mechanism and treatment pattern for APL DS and find a suitable biomarker for DS using multiomics approaches. Methods: Eighty newly diagnosed APL patients were recruited through Jan 2019 to Jan 2021 from a clinical trial (NCT04446806). Matched RNA and plasma samples of APL at presentation and DS were studied by RNA-seq and Human Cytokine Array. Two matched peripheral blood samples at presentation and DS from 2 severe DS patients were selected for 10×scRNA-seq analysis, compared with 3 peripheral blood and 2 bone marrow controls. Results: The incidence of DS was 35.3% (29/80), including 21.3% (17/80) moderate DS and 15% (12/80) severe DS. Bulk RNA-seq suggested immune response and cytokines interaction might play important roles in the development of DS ( Figure 1A and B). Significant downregulation of immune checkpoint molecules was shown in the DS period, such as GAL-9, which plays a crucial role in regulating the immune response ( Figure 1C). The activated CD4 +T and CD8 +T cells were amplification at diagnosis period compared with the corresponding CR/CRi period, then declined dramatically at DS period ( Figure 1 D). 10×scRNA-seq analysis revealed the activation of neutrophils and monocytes through innate immune response and inflammatory response ( Figure 1 E). Consistent with bulk RNA-seq results, apparent elevated expression of multiple inflammatory storm-related cytokines/receptors are shown in the DS period in monocytes and neutrophils, which indicates they contribute to the inflammatory cytokine storm ( Figure 1 F). These results indicated that ATRA induction overcomes immune evasion and induces highly activated immune response through downregulating immune checkpoint molecules. Based on 10×scRNA-seq data, differentiated promyelocytic leukemic cell, neutrophils and monocytes are major cell populations and expressed significantly higher cytokine and chemokine in DS stage, indicating that these cells might be major sources of the cytokine storm ( data not shown). We found S100A8 and S100A9, which function as danger-associated molecular pattern (DAMP) molecules and activate innate immune responses via binding to PRRs, significantly upregulated among all known alarmins ( Figure 1G). S100A8/A9 can be induced by ATRA induction, and also activate ERK, JAK-STAT and NF-κB signaling pathways ( Figure 1H). S100A8/A9 expression can be repressed by ERK inhibitor ( Figure 1I). Knockdown of S100A9 induced lower phosphorylation level of STAT1 and P65 ( Figure 1J). These results indicated S100A8/A9 were regulated by the ERK signaling and controlled the JAK-STAT and NF-κB signaling pathway. As a result, JAK-STAT related cytokines could be regulated by S100A8/A9 signaling. Importantly, ROC analysis showed that S100A8/A9 displayed both high sensitivity and specificity as a biomarker for predicting APL DS ( Figure 1K). According to clinical and cytokine storm characteristics of APL DS patients, Dexamethasone (DEX) and Ruxolitinib (RUX) were applied in the treatment of APL DS patients. The percentage of severe DS reduced remarkably after DEX prevention ( Figure 1L, P<0.05). The early death rate of APL declined under the DEX prevention and RUX treatment, and no patient died due to DS ( Figure 1M). The expression of a series of inflammatory cytokines dramatically decreased, indicating that the cytokine storm was effectively suppressed by the treatment of DEX and/or RUX ( Figure 1N). Conclusion s : Our data indicate that ATRA induction could overcome immune evasion through downregulating immune checkpoint molecules. ATRA-induced upregulation of S100A8/A9 may contribute to the cytokine storm observed in the DS stage of APL patients by activating the JAK-STAT and NF-κB signaling pathway. S100A8/A9 is recommended as a biomarker for predicting APL DS. Dexamethasone and Ruxolitinib are appropriate prevention and treatment pattern for APL DS patients.

Interleukin-12 induces IFN-γ secretion and STAT signaling implying its potential regulation of Th1 cell response in Nile tilapia.

As a pleiotropic cytokine consisting of IL-12p35 and IL-12p40, Interleukin-12 (IL-12) features in inflammation regulation and anti-bacterial immunity. While IL-12 homologs have been identified in non-mammalian species, the precise mechanisms by which IL-12 contributes to early adaptive immune responses in vertebrates remain incompletely understood. Herein, an evolutionary conserved Oreochromis niloticus IL-12 (defined as OnIL-12) was identified by synteny characterization, structural comparisons and phylogenetic pattern of IL-12p35b and IL-12p40a. IL-12p35b and IL-12p40a exhibited widespread expression in lymphoid-related tissues of tilapia, while their mRNA expression in head-kidney demonstrated a significant increase after Edwardsiella piscicida infection. Compared with other lymphocytes, recombinant OnIL-12 (rOnIL-12) displayed stronger affinity binding to T cells. Although stimulation of lymphocytes with the p35b or p40a subunit resulted in a significant induction of IFN-γ expression, rOnIL-12 showed stronger potential to promote IFN-γ expression than these subunits. rOnIL-12 not only elevated the mRNA expression level Th1 cell-associated transcription factor T-bet in lymphocytes, but also increased the proportion of CD4-1+IFN-γ+ lymphocytes. Moreover, the mRNA and phosphorylation levels of STAT1, STAT3, STAT4 and STAT5 were enhanced by rOnIL-12. These findings will offer previous evidence for further exploration into the regulatory mechanisms of Th1 cellular immunity in early vertebrates.

The Mixture of Natural Products SH003 Exerts Anti-Melanoma Effects through the Modulation of PD-L1 in B16F10 Cells.

Melanoma is the most invasive and lethal skin cancer. Recently, PD-1/PD-L1 pathway modulation has been applied to cancer therapy due to its remarkable clinical efficacy. SH003, a mixture of natural products derived from Astragalus membranaceus, Angelica gigas, and Trichosanthes kirilowii, and formononetin (FMN), an active constituent of SH003, exhibit anti-cancer and anti-oxidant properties. However, few studies have reported on the anti-melanoma activities of SH003 and FMN. This work aimed to elucidate the anti-melanoma effects of SH003 and FMN through the PD-1/PD-L1 pathway, using B16F10 cells and CTLL-2 cells. Results showed that SH003 and FMN reduced melanin content and tyrosinase activity induced by α-MSH. Moreover, SH003 and FMN suppressed B16F10 growth and arrested cells at the G2/M phase. SH003 and FMN also led to cell apoptosis with increases in PARP and caspase-3 activation. The pro-apoptotic effects were further enhanced when combined with cisplatin. In addition, SH003 and FMN reversed the increased PD-L1 and STAT1 phosphorylation levels induced by cisplatin in the presence of IFN-γ. SH003 and FMN also enhanced the cytotoxicity of CTLL-2 cells against B16F10 cells. Therefore, the mixture of natural products SH003 demonstrates therapeutic potential in cancer treatment by exerting anti-melanoma effects through the PD-1/PD-L1 pathway.

USP18 promotes endometrial receptivity via the JAK/STAT1 and the ISGylation pathway.

Interferon-tau (IFNT), a pregnancy recognition signal in ruminants, promotes the establishment of endometrial receptivity by inducing the expression of interferon-stimulated genes (ISGs) via the Janus kinase/signal transducer and activator of transcription (JAK/STATs) signaling pathway. However, the precise mechanisms remain largely unknown. Ubiquitin-specific protease 18 (USP18) acts specifically on the ISGylation modification system to exert deubiquitination and participates in the regulation of the type I IFN signaling pathway. The purpose of this study was to determine the role and mechanism of USP18 on endometrial receptivity in goat. USP18 was mainly localized in the uterine luminal and glandular epithelium, and its expression levels were significantly increased from days 5-18 of early pregnancy. Progesterone (P4), estradiol (E2), and IFNT significantly stimulated USP18 expression in goat endometrial epithelial cells (gEECs) cultured invitro. Meanwhile, the markers of endometrial receptivity HOXA11, ITGB1, ITGB3, and ITGB5 were significantly upregulated after USP18 overexpression in gEECs. However, USP18 interference significantly inhibited the expression of HOXA10, ITGB1, ITGB3, and ITGB5 in gEECs. In addition, both the phosphorylation levels of STAT1 and the expression of ISGylation-modified proteins were significantly increased after USP18 silencing in gEECs. Furthermore, pretreatment with the STAT1 inhibitor Fludara markedly restored the effect of USP18 interference in gEECs. In summary, USP18 may play an important role in promoting goat endometrial receptivity by regulating the JAK/STAT1 pathway and ISGylation.

Anti-PAI-1 Monoclonal Antibody Inhibits the Metastasis and Growth of Esophageal Squamous Cell Carcinoma.

Plasminogen activator inhibitor (PAI-1) is highly expressed in esophageal squamous cell carcinoma (ESCC) and strongly contributes to metastasis, making it a potential target for ESCC therapy. However, the antibodies and inhibitors targeting PAI-1 have not shown good therapeutic effect in the in vivo experiments yet. Here, we generated a panel of novel monoclonal antibodies (mAbs) against PAI-1. Analysis of PAI-1 expression in 90 tissue specimens and 128 serum specimens from ESCC patients with these mAbs confirmed that PAI-1 levels was significantly correlated with metastasis and poor survival. In addition, we found that high PAI-1 expression contributed to the enhanced motility and invasiveness of two ESCC cell lines. Next, mAb-1E2 and mAb-2E3, which have highest affinity with PAI-1, were shown to possess strong inhibitory effects on ESCC migration and invasion. Anti-tumor and anti-metastatic effects of mAb-2E3 were further demonstrated in the experimental animal models. Finally, LRP1 was identified as key factor mediating the pro-invasive function of PAI-1 and the anti-invasive capacity of mAb-2E3 in ESCC cells. The mAb-2E3 markedly decreased STAT1 phosphorylation levels and blocked the binding between PAI-1 and LRP1-ClusterII domain. Collectively, mAb-2E3 developed by our lab may be an effective antibody drug which can be used for anti-metastatic therapy in ESCC.

Mesenchymal stem/stromal cells primed by inflammatory cytokines alleviate psoriasis-like inflammation via the TSG-6-neutrophil axis

Psoriasis is currently an incurable skin disorder mainly driven by a chronic inflammatory response. We found that subcutaneous application of umbilical cord- derived mesenchymal stem/stromal cells (MSCs) primed by IFN-γ and TNF-α, referred to as MSCs-IT, exhibited remarkable therapeutic efficacy on imiquimod (IMQ)-induced psoriasis-like inflammation in mice. Neutrophil infiltration, a hallmark of psoriasis, was significantly reduced after treatment with MSCs-IT. We further demonstrated that the effects of MSCs-IT were mediated by tumor necrosis factor (TNF) stimulating gene-6 (TSG-6), which was greatly upregulated in MSCs upon IFN-γ and TNF-α stimulation. MSCs transduced with TSG-6 siRNA lost their therapeutic efficacy while recombinant TSG-6 applied alone could also reduce neutrophil infiltration and alleviate the psoriatic lesions. Furthermore, we demonstrated that TSG-6 could inhibit neutrophil recruitment by decreasing the expression of CXCL1, which may be related to the reduced level of STAT1 phosphorylation in the keratinocytes. Thus, blocking neutrophil recruitment by MSCs-IT or TSG-6 has potential for therapeutic application in human psoriasis.

Anti-Interferon-γ Autoantibodies Impair T-Lymphocyte Responses in Patients with Talaromyces marneffei Infections.

BackgroundAlthough anti-IFN-γ autoantibodies predispose patients to Talaromyces marneffei infection, whether this is mediated by T cell attenuation remains elusive.MethodsTotal peripheral blood mononuclear cells (PBMCs) from healthy donors or patients with T. marneffei infection were stimulated with M158−66, and immunodominant influenza H1N1 peptide, or heat-inactivated T. marneffei in the presence of serum from anti-IFN-γ autoantibody-positive patients or healthy controls. The percentages of IFN-γ+TNF+CD8+ T cells and IFN-γ+CD4+ T cells were determined by flow cytometry and cytokines released in the supernatant were detected by Cytometric Bead Array. Furthermore, PBMCs from patients with T. marneffei infection and healthy individuals were stimulated with IFN-γ and anti-CD3/CD28 beads, and the levels of STAT1 and STAT3 phosphorylation were detected by Western blot.ResultsThe M1-reactive CD8+ T cells that expressed IFN-γ+ TNF-α+ of healthy controls were clearly reduced in serum with high-titer anti-IFN-γ autoantibodies. In addition, the CD4+ T cell response, designated by the expression of IFN-γ, against T. marneffei in PBMCs of patients were significantly decreased when cultured in high-titer anti-IFN-γ autoantibody serum culture, compared to the healthy compartments. Moreover, the release of the cytokines IFN-γ, TNF-α and IL-2 was significantly decreased, while IL-10 was significantly increased. There was no significant difference in the phosphorylation levels of STAT1 and STAT3 protein between patients and healthy controls after IFN-γ or anti-CD3/CD28 beads stimulation.ConclusionAnti-IFN-γ autoantibodies presence in the serum inhibited CD4+ Th1 and CD8+ T cell immune responses. There was no congenital dysfunction of STAT1 and STAT3 in anti-IFN-γ autoantibody-positive patients with T. marneffei infection. These results suggest that the production of anti-IFN-γ autoAbs impair T-lymphocyte responses.

Anti-TIM1 suppresses airway inflammation and hyperresponsiveness via the STAT6 /STAT1 pathways in mice with allergic asthma.

T cell immunoglobulin and mucin domain-1 (TIM-1) is a transmembrane glycoprotein and has been reported as an molecular mechanism of allergic diseases. This study aimed to explore the effects of anti-TIM-1 monoclonal antibodies (anti-TIM1) on the development of allergic asthma. Female C57BL/6 mice were induced and challenged with ovalbumin (OVA) and received subsequent intranasal administration of anti-TIM1. The airway resistance of all mice was evaluated using a Buxco PFT system. Flow cytometry was used to detect the expression of TIM-1 in peripheral blood mononuclear cells. The level of cytokine production in the bronchial alveolar lavage fluid and serum was determined using ELISA. Mucous cells were observed using Alcian blue and periodic acid-Schiff staining. In addition, B-cell lymphoma gene 2(BCL2), T-box transcription factor (T-bet), GATA binding protein-3(GATA3), signal transducer and activator of transcription (STAT) 1, STAT6 were analyzed by western blot analysis. Their corresponding mRNA expression levels were determined by quantitative PCR. The mRNA expression level of Mucin 5AC in the lung tissues was also detected using quantitative RT-PCR. The results showed that the intranasal administration of anti-TIM1 ameliorated airway inflammation and hyperresponsiveness in an acute model of asthma. Following administration of anti-TIM1, both the mRNA and protein levels of T-bet were upregulated, while those of BCL2 and GATA3 were downregulated. Moreover, the phosphorylation levels of STAT1 and STAT6 were increased. Taken together, these findings demonstrated that intranasal administration of anti-TIM1 ameliorated allergic lung inflammation and remodeling in mouse models of asthma by repairing both the STAT1 and STAT6 pathways.

Transcriptomic Analysis of STAT1/3 in the Goat Endometrium During Embryo Implantation.

Interferon tau (IFNT), a pregnancy recognition signal in ruminants, promotes the establishment of embryo implantation by inducing the expression of interferon-stimulated genes (ISGs) via the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway. However, the precise regulatory mechanism of IFNT in goat embryo implantation remains largely unknown. In this study, we performed RNA sequencing of goat endometrial epithelial cells (gEECs) with or without 20 ng/mL IFNT treatment. Differential comparison showed that there were 442 upregulated differentially expressed genes (DEGs) and 510 downregulated DEGs. Bioinformatic analyses revealed that DEGs were significantly enriched in immune-related functions or pathways. The qRT-PCR validation results showed that the expression levels of STAT family members (STAT1, STAT2, and STAT3) were significantly upregulated in gEECs after IFNT treatment, which is in agreement with the RNA-seq data. Meanwhile, the protein levels of p-STAT1 and p-STAT3 increased significantly in gEECs after 6 and 24 h of IFNT treatment, respectively. Further in vivo experiments also confirmed that both mRNA and protein phosphorylation levels of STAT1 and STAT3 in the uterus on day 18 of pregnancy (P18) were significantly increased compared to those on day 5 (P5) and day 15 of pregnancy (P15). On P5, STAT1 and STAT3 proteins were primarily located in the uterine luminal epithelium (LE) and glandular epithelium (GE), and were also detected in the stromal cells. The intense immunostaining of STAT1 and STAT3 proteins were decreased on P15 and then increased on P18, especially in the superficial GE and subepithelial stromal cells. Moreover, p-STAT1 and p-STAT3 were highly expressed in the deep GE on P18. Collectively, these results highlight the role of IFNT in regulating endometrial receptivity in gEECs and uncover the temporal and spatial changes in the expression of STAT1/3 during embryo implantation in the goat endometrium.

Downregulated expression of IL‑28RA is involved in the pathogenesis of pancreatic ductal adenocarcinoma.

Pancreatic cancer ranks seventh in terms of cancer‑related mortality in men and women worldwide, where the most common subtype is pancreatic ductal adenocarcinoma (PDAC). To date, the pathogenesis of PDAC remains incompletely understood and the prognosis of PDAC is poor. In the present study, the expression of interleukin‑28 receptorα subunit (IL‑28RA) in PDAC tissues was detected using immunofluorescence staining and western blotting. IL‑28RA recombinant plasmids and control pCMV6‑entrymammalian expression plasmid, short hairpin (sh)IL‑28RA plasmids and control pRS scrambled shRNA vector purchased were used to produce stably transfected PANC‑1 cells overexpressing IL‑28RA or with IL‑28RA expression knocked down. MTS assays were used to measure cell viability and wound healing assay was used to assess the cell migratory ability invitro. Flow cytometry analysis was performed to determine the proportion of cells in each phase of the cell cycle whereas total protein and phosphorylated protein levels were assessed using western blotting. Xenograft models of subcutaneous tumors were established by injecting PANC‑1 cells hypodermically into nude mice to investigate the effect of IL‑28RA on tumorigenesis and tumor growth. The results showed that the expression of IL‑28RA in PDAC tissues was lower compared with that in normal tissues. IL‑28RA overexpression invitro resulted in the activation of the IL‑28RA pathway, which reduced cell viability and decreased the proportion of cells in the G2/M phase by reducing cyclin B1 expression. In addition, IL‑28RA overexpression inhibited migration of PDAC cells. By contrast, an increased proportion of cells in G2/M phase, upregulated cyclin B1 expression and enhanced cell viability and migratory ability along with inhibition of the IL‑28RA pathway were observed in PANC‑1 cells following IL‑28RA knockdown. The inhibitory effect of IL‑28RA was observed by tumor size in a nude mouse model induced by PANC‑1 cells with stable IL‑28RA overexpression or knockdown. The tumor size induced by PANC‑1 cells with stable IL‑28RA overexpression were smaller, whilst larger tumors induced by PANC‑1 cells were observed following stable IL‑28RA knockdown, when compared to control. Further studies showed that the effect of IL‑28RA on PDAC cells was exerted by regulating the phosphorylation levels of STAT1 and AKT. In conclusion, lower IL‑28RA expression may contribute to the pathogenesis of PDAC, where results from the present may provide further insights into the progression of PDAC, in addition to highlighting potentially novel therapeutic targets for this disease.

Chemical structure and anti-inflammatory activity of a branched polysaccharide isolated from Phellinus baumii

Phellinus baumii is used to treat inflammatory bowel disease (IBD) and gastroenteritis. In this study, a 46 kDa heteropolysaccharide SHPS-1 was isolated from fruiting bodies of P. baumii. SHPS-1 consisted of arabinose, mannose, glucose, and galactose at a molar ratio of 2.2:15.7:49.3:32.8. SHPS-1 had a backbone containing 1,3-linked β-D-Glcp and 1,6-linked α-D-Galp residues, and Araf, Manp and Galp units were attached as oligosaccharidic side chains to the backbone at C-6 of some glucopyranoses. SHPS-1 decreased phosphorylation level of STAT-1 and expression levels of STAT-1 targeted genes such as iNOS and TNF-α in lipopolysaccharide-stimulated macrophage RAW 264.7 cells. Furthermore, SHPS-1 promoted the expression of IL-10 and macrophage mannose receptor CD 206, markers of tissue repairing macrophages. SHPS-1 alleviated ulcerative colitis in mice by decreasing pro-inflammatory genes and increasing anti-inflammatory and tissue repairing genes. Collectively, SHPS-1 polysaccharide from P. baumii had anti-inflammatory activity and can potentially treat IBD.

Dexmedetomidine inhibits apoptosis of astrocytes induced by oxygen-glucose deprivation via targeting JAK/STAT3 signal pathway

ObjectiveThere is an increasing interest concerning the contribution of astrocytes to the intrinsic bioremediation of ischemic brain injury. The aim of this work was to disclose the effects and mechanism of dexmedetomidine (DEX) on the apoptosis of astrocytes under oxygen glucose deprivation (OGD) condition. MethodsPrimary cultured astrocytes separated from Sprague-Dawley (SD) rats were subjected to OGD treatment. Astrocytes were transfected with si-JMJD3 or pcDNA3.1-JMJD3 and then treated with DEX or JAK/STAT inhibitor (WP1066) before cell apoptosis was detected by TUNEL apoptosis kit. Western blot was applied to assess the level of apoptosis-related proteins Caspase-3, Bax and Bcl-2. Astrocyte cell viability was assessed by measuring the lactate dehydrogenase (LDH) level using a LDH assay kit. ResultsAstrocytes received OGD treatment had increased LDH and elevated apoptotic rate (P < 0.05). DEX could suppress OGD induced cytotoxic effect on astrocytes, as evidenced by decreased LDH release and suppressed cell apoptosis rate (P < 0.05). Meanwhile, DEX and WP1066 treatment were also found to inhibit the phosphorylation level of STAT1 and STAT3 (P < 0.05), indicating the DEX could suppress the activation of JAK/STAT signal pathway. JMJD3 overexpression in astrocytes could suppress the anti-apoptotic function of WP1066 in OGD treated astrocytes and hamper the protective effect of DEX in cell apoptosis (P < 0.05), suggesting that DEX and JAK/STAT signal pathway inhibits OGD induced apoptosis in astrocytes by down-regulating JMJD3. ConclusionDEX protects astrocytes against apoptosis via inhibiting JAK2/STAT3 signal pathway and downregulating JMJD3 expression in vitro.

PTP1B negatively regulates STAT1-independent Pseudomonas aeruginosa killing by macrophages

Pseudomonas aeruginosa is the main conditional pathogen of immunodeficiency individuals. The mechanisms governing immune response to P. aeruginosa infection by macrophages remain incompletely defined. Herein, we demonstrate that protein tyrosine phosphatase-1B (PTP1B) is a critical negative regulator of P. aeruginosa infection response by macrophages. PTP1B-deficient macrophages display greatly enhanced bacterial phagocytosis and killing, accompanied by increased lysosome formation during P. aeruginosa infection. We also found that PTP1B repressed nitric oxide (NO) production and nitric oxide synthase (iNOS) induction following P. aeruginosa infection. PTP1B deficiency tended to upregulate the production of TRIF-interferon (IFN) pathway cytokines and chemokines, including IFN-β and interferon γ-inducible protein 10 (CXCL10, IP-10). Unexpectedly, the phosphorylation level of STAT1 was not regulated by PTP1B. In vivo experiments also confirmed that the regulatory function of PTP1B was not dependent on STAT1. These findings demonstrate that STAT1 is dispensable for negative regulation of P. aeruginosa clearance by macrophages.

IL‑27 suppresses airway inflammation, hyperresponsiveness and remodeling via the STAT1 and STAT3 pathways in mice with allergic asthma.

Type 2 cytokine-associated immunity may be involved in the pathogenesis of allergic asthma. Although interleukin 27 (IL-27) has been reported as an initiator and suppressor of T-helper 1 (Th1) and T-helper 2 (Th2) responses, respectively, its effects on the development of asthma remain unclear. In the present study, mice were induced and challenged with ovalbumin and received subsequent intranasal administration of IL-27. Total and differential cell counts were determined from Wright-Giemsa-stained cytospins, whereas the cytokine levels were detected using ELISA. In addition, the expression levels of signal transducer and activator of transcription (STAT) 1, STAT3, GATA-binding protein-3 (GATA3) and T-bet (T-box transcription factor) were analyzed in T cells by western blot analysis. Their corresponding mRNA expression levels were determined by quantitative PCR. Airway remodeling was assessed by conventional pathological techniques. The results indicated that intranasal administration of IL-27 ameliorated airway inflammation and hyperresponsiveness in an acute model of asthma. Furthermore, IL-27 prevented airway remodeling in a chronic model of asthma. Following administration of IL-27, the mRNA expression levels of STAT1 and T-bet were upregulated, while those of GATA3 were downregulated. Moreover, the phosphorylation levels of STAT1 and STAT3 were increased. Taken together, these findings demonstrated that intranasal administration of IL-27 ameliorated Th2-related allergic lung inflammation and remodeling in mouse models of asthma by repairing both the STAT1 and STAT3 pathways.

Trichothecin Inhibits Cancer-Related Features in Colorectal Cancer Development by Targeting STAT3.

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that contributes to cancer progression through multiple processes of cancer development, which makes it an attractive target for cancer therapy. The IL-6/STAT3 pathway is associated with an advanced stage in colorectal cancer patients. In this study, we identified trichothecin (TCN) as a novel STAT3 inhibitor. TCN was found to bind to the SH2 domain of STAT3 and inhibit STAT3 activation and dimerization, thereby blocking STAT3 nuclear translocation and transcriptional activity. TCN did not affect phosphorylation levels of STAT1. TCN significantly inhibited cell growth, arrested cell cycle at the G0/G1 phase, and induced apoptosis in HCT 116 cells. In addition, the capacities of colony formation, migration, and invasion of HCT 116 cells were impaired upon exposure to TCN with or without IL-6 stimulation. In addition, TCN treatment abolished the tube formation of HUVEC cells in vitro. Taken together, these results highlight that TCN inhibits various cancer-related features in colorectal cancer development in vitro by targeting STAT3, indicating that TCN is a promising STAT3 inhibitor that deserves further exploration in the future.

Exogenous dihydrosphingosine 1 phosphate mediates collagen synthesis in cardiac fibroblasts through JAK/STAT signalling and regulation of TIMP1

Cardiac fibrosis and myocyte hypertrophy are hallmarks of the cardiac remodelling process in cardiomyopathies such as heart failure (HF). Dyslipidemia or dysregulation of lipids contribute to HF. The dysregulation of high density lipoproteins (HDL) could lead to altered levels of other lipid metabolites that are bound to it such as sphingosine-1- phosphate (S1P). Recently, it has been shown that S1P and its analogue dihydrosphingosine-1-phosphate (dhS1P) are bound to HDL in plasma. The effects of dhS1P on cardiac cells have been obscure. In this study, we show that extracellular dhS1P is able to increase collagen synthesis in neonatal rat cardiac fibroblasts (NCFs) and cause hypertrophy of neonatal cardiac myocytes (NCMs). The janus kinase/signal transducer and activator (JAK/STAT) signalling pathway was involved in the increased collagen synthesis by dhS1P, through sustained increase of tissue inhibitor of matrix metalloproteinase 1 (TIMP1). Extracellular dhS1P increased phosphorylation levels of STAT1 and STAT3 proteins, also caused an early increase in gene expression of transforming growth factor-β (TGFβ), and sustained increase in TIMP1. Inhibition of JAKs led to inhibition of TIMP1 and TGFβ gene and protein expression. We also show that dhS1P is able to cause NCM hypertrophy through S1P-receptor-1 (S1PR1) signalling which is opposite to that of its analogue, S1P. Taken together, our results show that dhS1P increases collagen synthesis in cardiac fibroblasts causing fibrosis through dhS1P-JAK/STAT-TIMP1 signalling.

Porcine circovirus 3 Cap inhibits type I interferon signaling through interaction with STAT2

Porcine circovirus 3 (PCV3) is a novel circovirus that is associated with porcine dermatitis and nephropathy syndrome, reproductive failure, and multi-systemic inflammation. The type I Interferon (IFN) signaling pathway is an important innate immune signaling pathway for defense against viral infection. Many mammalian viruses inhibit host innate immune signaling through diverse strategies. Here, we found that the PCV3 capsid protein (Cap) significantly inhibited IFN-β-stimulated response element (ISRE) promoter activity, suggesting that Cap suppresses IFN signaling. However, Cap did not affect expression and phosphorylation levels of STAT1 and STAT2 and did not interrupt the heterodimerization of pSTAT1 and pSTAT2. Although Cap interacted with KPAN1, it did not block the interaction between KPNA1 and pSTAT1 or the nuclear translocation of pSTAT1 and pSTAT2. Interestingly, we found that Cap inhibited the activation of ISRE promoter induced by IRF9-S2C. Mechanistically, Cap interacted with the transactivation domain of STAT2, a key protein in type I IFN signaling. In addition, we found that Cap bound to ISRE and prevented ISRE binding of IRF9-S2C. This work is the first to describe the mechanism of inhibition of IFN signaling by PCV3 Cap.