IL-21／STAT3通路在溃疡性结肠炎小鼠发病中的表达及其意义

目的探讨IL-21／STAT3通路在溃疡性结肠炎（ulcerativecolitis,UC）小鼠肠道中的表达及其作用。方法20只BALB／C小鼠随机分为正常组和DSS模型组各10只。小鼠UC模型用葡聚糖硫酸钠dextransodiumsulphate,DSS）诱导,观察小鼠疾病活动指数（DAI）评分、病变结肠常规病理切片,采用ELISA法检测血清IL-6、IL-21含量,免疫组化检测结肠STAT3表达。结果模型组小鼠DAI评分、血清IL-6和IL-21含量、结肠病理评分、黏膜STAT3表达水平均较正常组高,差异有显著性（P〈0．05）。结论溃疡性结肠炎小鼠血清炎症介质及肠道STAT3表达水平明显升高,推测IL-21／STAT3通路可能参与UC小鼠肠道炎症损伤,阻断病变肠道IL-21／STAT3通路,减少STAT3蛋白表达或许是治疗UC的作用靶点。     

SOCS1 hypermethylation mediated by DNMT1 is associated with lipopolysaccharide-induced inflammatory cytokines in macrophages

Macrophages activation which releases the pro-inflammatory cytokines is an essential event in the process of inflammation. SOCS1 has been shown to act as a negative regulator of cytokine signals and plays a key role in the suppression of tissue injury and inflammatory diseases. DNA methylation mediated by specific DNA methyltransferases1 (DNMT1) which contributes to the epigenetic silencing of multiple genes. SOCS1 promoter hypermethylation is by far the best categorized epigenetic change in tumors. Our study with a view to investigate whether the loss of SOCS1 due to SOCS1 promoter methylation was involved in the course of inflammatory cytokines released from lipopolysaccharide (LPS)-stimulated macrophages. Here, we found that treatment of LPS-induced RAW264.7 macrophage cells with the DNA methylation inhibitor 5-aza-2′-deoxycytidine (5-azadC) reduced aberrant promoter hypermethylation of SOCS1 and prevented the loss of the expression of SOCS1 in macrophages which secret inflammatory cytokines. Knockdown of DNMT1 gene not only attenuated the SOCS1 gene promoter methylation but also up-regulated the expression of SOCS1 in activated RAW264.7 cells. Furthermore, silencing of DNMT1 prevented the activation of JAK2/STAT3 pathway in LPS-induced RAW264.7 cells. These studies demonstrated that DNMT1-mediated SOCS1 hypermethylation caused the loss of SOCS1 expression results in negative regulation of activation of the JAK2/STAT3 pathway, and enhanced the release of LPS-induced pro-inflammatory cytokines such as TNF-α and IL-6 in macrophages.     

IL-10 plays a pivotal role in anti-inflammatory effects of resveratrol in activated microglia cells

The development of agents that can modulate microglial activation has been suggested as one potential strategy for the treatment or prevention of neurodegenerative diseases. Among these agents, resveratrol, with its anti-inflammatory action, has been described to have neuroprotective effects. In this paper we demonstrate that in LPS-stimulated microglia resveratrol pretreatment reduced, in a dose-dependent manner, pro-inflammatory cytokines IL-1β, TNF-α and IL-6 mRNA expression and increased the release of anti-inflammatory interleukin (IL)-10. Moreover, resveratrol pretreatment up-regulated the phosphorylated forms of JAK1 and STAT3, as well as suppressor of cytokine signaling (SOCS)3 protein expression in LPS activated cells, demonstrating that the JAK–STAT signaling pathway is involved in the anti-inflammatory effect exerted by resveratrol. By supplementing the cultures with an IL-10 neutralizing antibody (IL-10NA) we obtained the opposite effect. Taken together, these data allow us to conclude that the LPS-induced pro-inflammatory response in microglial cells can be markedly reduced by resveratrol, through IL-10 dependent up-regulation of SOCS3, requiring the JAK–STAT signaling pathway.     

Effect of Diacerein on HOTAIR/IL-6/STAT3, Wnt/β-Catenin and TLR-4/NF-κB/TNF-α axes in colon carcinogenesis

Colorectal cancer (CRC) is a common malignancy with high mortality and poor prognosis. Diacerein (DIA) is an anti-inflammatory used for treatment of osteoarthritis. We delineated some underlying molecular mechanisms of DIA’s anti-carcinogenic effect in CRC using in vivo and in vitro models. Human Caco-2 cells were treated with DIA followed by MTT and Annexin V assays and CRC was experimentally induced using 1,2-dimethylhydrazine. DIA (50 mg/kg/day, orally) was administrated for 8 weeks. The MTT assay confirmed cytotoxic effect of DIA in vitro and Annexin V confirmed its apoptotic effect. DIA resulted in regression of tumour lesions with reduced colonic TLR4, NF-κB and TNF-α protein levels and down-regulated VEGF expression, confirming anti-angiogenic impact. DIA triggered caspase-3 expression and regulated Wnt/β-Catenin pathway, by apparently interrupting the IL-6/STAT3/ lncRNA HOTAIR axis. In conclusion, DIA disrupted IL-6/STAT3/ lncRNA HOTAIR axis which could offer an effective therapeutic strategy for the management of CRC.     

TAK-242通过调控JAK2/STAT3通路抑制小鼠心肌缺血再灌注损伤炎症反应

目的：探讨Toll样受体4拮抗剂TAK-242抑制小鼠心肌缺血/再灌注损伤（ischemia/reperfusion,I/R）炎症反应的分子机制。方法：选用48只雄性C57BL/6小鼠随机分为4组：假手术组（sham）、模型组（I_30min /R_24h）、给药组[I/R+TAK-242（3 mg·kg^-1）]、干预组[I/R+TAK-242+AG490（15 mg·kg^-1）]。再灌注24 h后心脏超声检测小鼠心功能,氯化三苯基四氮唑（TTC）染色法测定心肌梗死面积,HE染色观察心肌病理改变,WB检测心肌JAK2/STAT3磷酸化水平,ELISA检测血清IL-6、TNF-α、IL-10和高迁移率族蛋白B1（HMGB1）浓度。结果：与sham组比较,I/R组小鼠左心室收缩期直径（LVIDs）延长（P<0.01）,左心室射血分数（LVEF）和左心室短轴缩短分数（LVFS）显著降低（P<0.001或P<0.01）,心梗面积明显增加并出现心肌炎性浸润,心肌p-JAK2/p-STAT3表达明显升高（P<0.01或P<0.05）,血清IL-6、IL-10、TNF-α和HMGB1水平显著升高（P<0.001或P<0.01）。与I/R组比较,TAK-242给药组小鼠LVIDs缩短（P<0.05）,LVEF和LVFS显著升高（P<0.01或P<0.05）,心梗面积缩小（P<0.01）,心肌炎症浸润减轻,心肌p-JAK2/p-STAT3表达降低（P<0.01或P<0.05）,血清IL-6和TNF-α水平明显下降（P<0.001或P<0.01）,而IL-10和HMGB1浓度进一步升高（P<0.01）。与TAK-242给药组比较,AG490干预可显著加强TAK-242治疗作用,包括心肌收缩功能增强,心梗面积缩小及炎性浸润程度减轻,心肌p-JAK2/p-STAT3表达降低（P<0.05）,血清IL-6、TNF-α浓度下降而IL-10、HMGB1浓度升高（P<0.01或P<0.05）。结论： Toll样受体4拮抗剂TAK-242抑制小鼠I/R炎症反应与JAK2/STAT3信号通路失活有关。     

酪氨酸激酶抑制剂A77-1726阻断IL-13介导STAT6磷酸化和c-fos表达

目的研究酪氨酸激酶抑制剂A77-1726对IL-13介导Dami细胞STAT6磷酸化和c-fos表达的影响,为A77-1726的临床应用和IL-13的信号通路研究提供新的实验依据。方法提取Dami细胞总RNA,RT-PCR检测c-fos mRNA表达。提取Dami细胞总蛋白,Western blot检测磷酸化STAT6和c-fos蛋白表达。凝胶定量软件Quantity One检测电泳条带光密度,统计学分析。结果100μg·L-1IL-13作用Dami细胞,可见STAT6磷酸化,50μmol·L-1A77-1726可阻断IL-13诱导的Dami细胞STAT6磷酸化。IL-13作用Dami细胞,c-fos mRNA表达增高(P<0.05),50μmol·L-1A77-1726阻断了IL-13诱导的Dami细胞c-fos mRNA的表达(P<0.05)。IL-13促进Dami细胞c-fos蛋白表达(P<0.05),50μmol·L-1A77-1726作用Dami细胞,阻断了IL-13诱导的c-fos蛋白表达(P<0.05)。结论酪氨酸激酶抑制剂A77-1726阻断了IL-13介导的白血病Dami细胞STAT6磷酸化和c-fos表达,JAK/STAT6通路是IL-13信号通路之一,IL-13诱导的c-fos表达与STAT6通路相关。     

Kupffer cell depletion attenuates IL-6/STAT3 mediates hepatocyte apoptosis in immunological liver injury of trichloroethylene sensitized mice

Trichloroethylene (TCE) induced TCE hypersensitivity syndrome which makes immune injuries in multi-system. The multiple organ damage included skin, liver, kidney and so on. The main manifestations of liver injuries were apoptosis and edema of hepatocytes. In our previous research, we found the activation of Kupffer cells (KCs) which increased IL-6 can aggravate liver cell apoptosis in TCE sensitized mice. However, the mechanism of IL-6 in liver damages induced by TCE was not clear. This study explored the function of IL-6/STAT3 signal pathway on the TCE induced apoptosis of liver cell. We established a TCE sensitized BALB/c mouse model with a KCs inhibitor GdCl₃, we found that the expressions of ALT and AST in TCE sensitization positive mice were higher than other mice, and the expressions of apoptosis-related proteins were up-regulated in TCE sensitization positive mice, GdCl₃ could alleviate this process. Meanwhile, GdCl₃ could significantly decrease the expressions of IL-6/STAT3 proteins. All in all, the activation of KCs can increase the expression of IL-6, IL-6R and phosphorylate STAT3, induces hepatocyte apoptosis, and participates in immunity damage of liver which induced by TCE.     

Shikonin suppresses IL-17-induced VEGF expression via blockage of JAK2/STAT3 pathway

IL-17 signaling in keratinocytes plays an important role in psoriasis, which is a benign, chronic skin disease characterized by keratinocytes hyperproliferation and increased dermal vascularity. Shikonin, isolated from the traditional medical herbs Lithospermum erythrorhizon, has long been found to possess different medicinal properties such as antibacterial, improving wound healing, anti-inflammatory and anti-tumor effects. However, the effects and mechanisms of shikonin on VEGF expression in keratinocytes mediated by IL-17 signaling, are still not fully clarified. In the present study, we investigated the effects and regulatory mechanisms of shikonin on VEGF expression in keratinocytes induced by IL-17 by in vitro and in vivo experiments. Our results showed that shikonin significantly inhibited IL-17-induced VEGF mRNA and protein expression in HaCaT cells and the secretion of VEGF by HaCaT cells, inhibited IL-17-induced IL-17R, pJAK2 and pSTAT3 expression, while up-regulated the expression of SOCS1 in HaCaT cells. Additionally, shikonin effectively suppressed VEGF expression in the skin of IL-17 stimulated mice. Furthermore, shikonin suppressed VEGF-induced tube formation of HUVECs and CD34 expression in the skin of IL-17 stimulated mice. These results imply that shikonin suppresses IL-17-induced VEGF expression in vitro and in vivo and the mechanisms may be related to its effect in blockage of JAK2/STAT3 pathway. These data deepen our understanding of shikonin in the inhibition of angiogenesis in inflammatory skin diseases such as psoriasis.     

藤梨根提取物通过 IL-6/STAT3信号通路调控食管癌细胞生物学行为的研究

目的探讨藤梨根提取物通过白细胞介素 -6/信号传导因子及转录激活因子 3(IL-6/STAT3)信号通路调控食管癌 EC9706细胞生物学行为的研究。方法本实验研究自 2018年 10月到 2019年 6月,分别用 1、5、10、100、500、1 000 mg/L的藤梨根提取物处理食管癌 EC-9706细胞,选取 100 mg/L作为最佳逆转实验浓度;用 IL-6/STAT3信号通路激活剂处理食管癌 EC-9706细胞。甲基噻唑基四唑( MTT)检测细胞的毒性;流式细胞术检测细胞的凋亡率; Transwell法检测细胞的迁移和侵袭;划痕实验检测细胞的运动能力;蛋白免疫印迹法( Western blotting)检测细胞周期蛋白 1(Cyclin D1)、周期蛋白依赖性激酶抑制因子(P21)、 B淋巴细胞瘤 -2相关蛋白(Bax)、 B淋巴细胞瘤 -2(Bcl-2)基质金属蛋白酶 -2(MMP-2)、基质金属蛋白酶 -9(MMP-9)、信号传导及转录活化因子 3(STAT3)、磷酸化的信号传导与转录激活因、子-3(p-STAT3)蛋白的表达。结果藤梨根提取物明显促进了食管癌 EC-9706细胞凋亡( 37.35±2.37)并抑制了细胞增殖( 21.33±3.91)、迁移( 106.31±3.20)和侵袭( 67.29±2.99)(P<0.05);下调 CyclinD1(0.25±0.01)、 Bcl-2(0.26±0.03),、MMP-2(0.27±0.03)、 MMP-9(0.25±0.01)、 STAT3(0.34±0.03)、 p-STAT3(0.20±0.01)     

Effect of dexamethasone on STAT6-dependent Ym1/2 expression in vivo and in vitro

Ym1 and Ym2 (Ym1/2) are chitinase-like proteins and we reported previously that IL-4 induced Ym1/2 in mouse bone marrow-derived mast cells. In the present study, ovalbumin-induced asthmatic mice were used to investigate the effect of glucocorticoids on Ym1/2 expression. Ym1/2 were highly induced in bronchoalveolar lavage fluid (BALF) and the lung. Ym1/2 expression was completely inhibited by dexamethasone (Dex) in BALF and weakly inhibited in the lung. Primary cultured macrophages were used to investigate the inhibition of Ym1/2 expression at the cellular level. Although Dex pretreatment inhibited the Ym1/2 expression level in an animal model, it did not reduce IL-4 induction of Ym1/2 expression in vitro. Next, we tested whether Dex blocks IL-4 induced STAT6 signaling and found that it had no inhibitory effect on the phosphorylation level of STAT6 in macrophages. The luciferase reporter assay also revealed that Dex did not inhibit IL-4 induction of Ym1/2 promoter activity. These results indicate that the inhibitory effect of Dex on Ym1/2 protein expression in the murine model of asthma does not involve the STAT6 signaling pathway.     

Activation of PI3-K/Akt pathway for thermal preconditioning to protect cultured cerebellar granule neurons against low potassium-induced apoptosis

AIM: This study was designed to investigate whether the activation of the phosphatidylinositol 3-kinase (PI3-K)/Akt pathway is required for thermal preconditioning to protect rat cerebellar granule neurons (CGN) against apoptosis induced by low potassium, and to explore the possibility of a link between the upregulated heat shock protein (HSP)70 expression and Akt activation in the acquisition of neuroprotection induced by thermal preconditioning. METHODS: CGN cultured for 8 d in vitro were switched to 5K medium for 24 h after thermal preconditioning (TP; 43.5 degree for 90 min, then 37 degree for 1 h). To study the role of the PI3-K/Akt pathway, a PI3-K inhibitor, LY294002 (20 micromol/L) was added into the cultures 1 h before TP. 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay and fluorescein diacetate staining were used to determine cell viability. Hoechst 33258 staining and agar gel electrophoresis were used to test the morphological and biological characters of CGN. Western blot analysis was employed to detect the levels of phospho-Akt, phospho-glycogen synthase kinase 3beta (GSK3beta) Akt, GSK3beta, and HSP70. RESULTS: TP protected CGN against apoptosis induced by low potassium. LY294002 inhibited the neuroprotective effect on CGN induced by TP. TP induced a robust activation of Akt and the inactivation of GSK3beta via PI3-K. Furthermore, the activation of the PI3-K/Akt pathway by TP persisted for 24 h in the 5K cultures. LY294002 (20 micromol/L) failed to inhibit the upregulated HSP70 expression induced by TP. CONCLUSION: The activation of the PI3-K/Akt pathway is required for TP to protect CGN against apoptosis induced by low potassium, but the neuroprotective effect by Akt activation is not mediated through the downstream induction of HSP70 expression.     

Ulinastatin affects focal cerebral ischemia–reperfusion injury via SOCS1-mediated JAK2/STAT3 signalling pathway

Cerebral ischemia results in loss of cerebral blood flow, which contributes to neuronal damage, neurocognitive impairment, as well as learning and memory difficulties. Although reperfusion is necessary to restore the blood supply to the brain, it also leads to several detrimental effects on the brain. The purpose of this study was to assess the effects of ulinastatin (UTI) on preventing focal cerebral ischemia/reperfusion-induced injury (FCIRI). First, a rat model of FCIRI was established and treated with UTI. The effects of UTI on FCIRI in rats were evaluated using Morris water maze assay, triphenyl tetrazolium chloride staining, TUNEL, western blot assay, and enzyme-linked immunosorbent assay analysis. UTI was found to improve the learning memory ability, reduce infarction area, inhibit apoptosis and decrease inflammation in FCIRI rats. Messenger RNA microarray analysis of hippocampal tissues revealed that suppressor of cytokine signalling-1 (SOCS1) was the downstream target of UTI in FCIRI. SOCS1 depletion impaired the protective effect of UTI on FCIRI in rats. SOCS1 blocked the activation of the JAK2/STAT3 pathway. JAK2 inhibitor caused the JAK2/STAT3 pathway deficit, hence reversing the effect of sh-SOCS1 on FCIRI in rats. Taken together, our results demonstrate that UTI alleviated FCIRI in rats, which was, to some extent, related to SOCS1-mediated JAK2/STAT3 pathway.