Perillyl alcohol efficiently scavenges activity of cellular ROS and inhibits the translational expression of hypoxia-inducible factor-1α via mTOR/4E-BP1 signaling pathways

Perillyl alcohol (POH) is a dietary monoterpene present in a variety of plants with a pure or mixed form, and it is one of the very few natural substances with anticancer activity. However, the mechanism by which POH unleashes its anticancer activity in tumor cells remains unclear. We here demonstrated the effect of POH on hypoxia-inducible factor-1α (HIF-1α) activation. POH showed the potent inhibitory activity against HIF-1 activation induced by hypoxia in various human cancer cell lines and efficient scavenging activity of cellular Reactive oxygen species (ROS) by hypoxia in tumor cells. Further analysis revealed that POH inhibited HIF-1α protein synthesis, without affecting the expression level of HIF-1α mRNA or degradation of HIF-1α protein. Moreover, we found that suppression of HIF-1α accumulation by POH correlated with strong de-phosphorylation of mammalian target of rapamycin (mTOR) and eIF4E binding protein-1 (4E-BP1), and eukaryotic initiation factor 4E (eIF4E). These results showed that POH inhibited HIF-1α protein synthesis through the inhibition of mTOR/4E-BP1 signaling pathways. Furthermore, POH increased the expression of p53, p21, induced cell cycle arrest in the G1 phase as well as decreased cyclin D1, c-Myc, and Skp2 expression. In vivo studies further confirmed the inhibitory effect of POH on the expression of HIF-1α proteins, leading to a decrease growth of HCT116 cells in a xenograft tumor model. There results show that POH is an effective inhibitor of HIF-1 and provide new perspectives in to the mechanism of its anticancer activity.     

缺氧对食管癌细胞缺氧诱导因子-1α及己糖激酶表达的影响

目的探讨不同缺氧程度对食管癌细胞株TE1中缺氧诱导因子-1α（Hypoxia-inducible factor-1α,HIF-1α）及糖酵解关键酶表达的影响。方法 TE1细胞分别在正常氧分压和缺氧条件下培养,缺氧时间设定为6、12、24及48h,使用Western blot方法检测缺氧培养不同时间后细胞中HIF-1α及糖酵解关键酶己糖激酶II（Hexokinase-II,HK-II）的蛋白水平表达变化。结果常氧及缺氧条件下TE1细胞中HIF-1α及HK-II均有表达,缺氧后表达均较常氧培养时明显增强,且随缺氧时间不同而呈先增多后减少的动态变化。结论低氧能够增加食管癌细胞中HIF-1α及HK-II表达而促进糖酵解进程,联合抑制HIF-1α和糖酵解酶可能成为治疗食管癌的潜在的靶点。     

Curcumin relieves TPA-induced Th1 inflammation in K14-VEGF transgenic mice

Curcumin has been confirmed to have anti-inflammatory properties in addition to the ability to decrease the expression of pro-inflammatory cytokines in keratinocytes. It was suggested that the interleukin-23 (IL-23)/IL-17A cytokine axis played a critical role in the pathogenesis of 12-O-tetradecanoyl phorbol 12-myristate 13-acetate (TPA)-induced K14-VEGF transgenic psoriasis-like mice model. Here, we report that topical use of a curcumin gel formulation inhibited TPA-induced Th1 inflammation in K14-VEGF transgenic mice ears but not Th17 inflammation as expected. Real-time PCR showed that mRNA levels of IL-23, IL-17A, IL-22, IL-6 and TNFα cytokines failed to increase after TPA-induction in K14-VEGF transgenic mice ear skin; but the mRNA level of IFNγ increased significantly at the same time. Furthermore, TPA-induction up-regulated the TCRγδ protein but failed to impact the CCR6 protein, which means that the proliferation of γδ T cells is incapable of IL-17A production. We find that curcumin is capable of relieving TPA-induced inflammation by directly down-regulating IFNγ production. In conclusion, curcumin inhibits TPA-induced Th1 inflammation in K14-VEGF transgenic mice which has not been previously described.     

Cinnamaldehyde suppresses NLRP3 derived IL-1β via activating succinate/HIF-1 in rheumatoid arthritis rats

Cinnamaldehyde (CA) is an essential component of cinnamon (Cinnamomum cassia Presland), which is often used as a flavoring condiment in beverages, pastries, perfumes, etc. Cinnamon is also used as herbal medicine in China and Southeast Asia to treat rheumatoid arthritis. However, the molecular mechanism is unclear. In this study, we aim to investigate its anti-inflammatory effects against Rheumatoid arthritis (RA) using activated macrophages (Raw246.7) in vitro and adjuvant arthritis rats (AA) in vivo. The results demonstrated that CA significantly reduced synovial inflammation in AA rats, possibly due to suppression of the expressions of pro-inflammatory cytokines, especially the IL-1β. Further investigation found that CA also suppressed the activity of HIF-1α by inhibiting the accumulation of succinate in cytoplasm. As we know, the reduction of HIF-1α nucleation slows down IL-1β production, because HIF-1α activates the expression of NLRP3, which is involved in the assembly of inflammasome and processing of IL-1β. In addition, CA also inhibited the expression of the succinate receptor GPR91, which in turn inhibited the activation of HIF-1α. In conclusions, our results suggested that CA might be a potential therapeutic compound to relieve rheumatoid arthritis progress by suppressing IL-1β through modulating succinate/HIF-1α axis and inhibition of NLRP3.     

Molecular control of pathogenic Th17 cells in autoimmune diseases

IL-17A-producing CD4⁺ T helper cells (Th17) are crucial for the development of inflammatory and autoimmune diseases and thus are exploited for clinical immunotherapies. Emerging evidence suggests Th17 cells are heterogeneous and able to adopt both pathogenic and non-pathogenic phenotypes which are shaped by environmental and genetic factors. On one hand, IL-6 in concert with TGFβ1 can induce non-pathogenic Th17 cells (non-pTh17), which are not effective in inducing tissue inflammation. On the other hand, IL-6, IL-1β with IL-23 induce pathogenic Th17 cells (pTh17) to induce immune pathologies in various tissues. Th17 cells could be both pathogenic and non-pathogenic in a content-dependent manner in vivo. Understanding how the generation and pathogenicity of pTh17 cells are regulated will aid us to devise more effective immunotherapy. In this review, we summarize recent advances in the differentiation and regulation of Th17 cells especially pTh17 cells in vitro and in vivo. The emerging results revealing the specific molecular control of pTh17 cells are highlighted.     

银杏内酯、刺五加皂苷和人参皂苷诱导PC12细胞缺氧诱导因子-1α表达

目的缺氧诱导因子-1α(HIF-1α)在介导心肌和脑低氧/缺血的适应性反应中起重要作用,本文研究银杏内酯、刺五加皂苷和人参皂苷的药理作用机制是否与HIF-1α表达及其相关信号通路有关。方法MTT比色法观察PC12细胞活性,蛋白质免疫印迹法分析PC12细胞HIF-1α及磷酸化细胞外信号调节激酶1/2(p-ERK1/2)蛋白表达,RT-PCR观察HIF-1αmRNA表达。结果一定浓度范围的银杏内酯、刺五加皂苷或人参皂苷均可促进PC12细胞的活性,在浓度分别为37.5,50和60mg·L-1时达最好效果;银杏内酯(37.5mg·L-1)、刺五加皂苷(50mg·L-1)或人参皂苷(60mg·L-1)处理PC12细胞24h均可诱导p-ERK1/2和HIF-1α表达增高,且引起HIF-1αmRNA表达水平的上调,提示HIF-1α蛋白水平的增高与其合成增加有关。结论银杏内酯、刺五加皂苷和人参皂苷均可诱导PC12细胞表达HIF-1α,该作用可能与激活MAPK信号通路有关。     

金雀异黄素对IL-1α刺激破骨样细胞的组织蛋白酶K表达的影响

目的探讨金雀异黄素对白细胞介素1α(IL-1α)刺激破骨样细胞组织蛋白酶K(CK)表达的作用.方法从人骨巨细胞瘤组织中纯化出破骨样细胞(OCLs),用不同浓度的金雀异黄素或1 7β-雌二醇(17β-E2)孵育,并设空白对照组和阳性对照组,采用RT-PCR和Western blot方法,观察IL-1α刺激后CK的表达.结果与空白对照组相比,IL-1α刺激CK表达显著增加(P＜0.01);金雀异黄素在转录水平下调IL-1α刺激后CK的表达,且呈剂量依赖关系(r=0.68,P＜0.01);金雀异黄素下调IL-1α刺激后CK的蛋白表达,且呈剂量依赖关系(r=0.61,P＜0.01).雌激素受体拮抗剂ICI 182.780可以部分抑制金雀异黄素的上述作用.结论金雀异黄素可通过破骨样细胞的雌激素受体部分抑制IL-1α刺激后CK的表达.     

HIF-1α and HIF-2α are critically involved in hypoxia-induced lipid accumulation in hepatocytes through reducing PGC-1α-mediated fatty acid β-oxidation

During periods of cellular hypoxia, hepatocytes adapt to consume less oxygen by shifting energy production from mitochondrial fatty acid β-oxidation to glycolysis. One of the earliest responses to pathologic hypoxia is the activation of the hypoxia-inducible factor (HIF). In the present study, we examined whether HIF-1 and HIF-2 were involved in the regulation of fatty acid synthesis and β-oxidation. We showed that hypoxia induced fat accumulation in the livers of mice and in HepG2 cells. These hypoxia-induced changes in fatty acid metabolism were mediated by suppressing fatty acid β-oxidation, without significantly influencing fatty acid synthesis. Exposing hepatocytes to 1% O₂ reduced the mRNA expression of carnitine palmitoyltransferase 1 (CPT-1), which catalyzes the rate-limiting step in the mitochondrial import of fatty acids for β-oxidation. Moreover, hypoxia exposure reduced proliferator-activated receptor-γ coactivator-1α (PGC-1α) protein levels, which plays an important role in regulation of β-oxidation. Exposure of HIF-1α or HIF-2α deficient hepatocytes to hypoxia abrogated the reduction in PGC-1α and CPT-1 expression and cellular lipid accumulation observed in normal hepatocytes exposed to hypoxia. These results suggest that both HIF-1α and HIF-2α are involved in hypoxia-induced lipid accumulation in hepatocytes via reducing PGC-1α mediated fatty acid β-oxidation.     

Involvement of hypoxia-inducible factor-1α in the oxidative stress induced by advanced glycation end products in murine Leydig cells

Hyperglycemia increases the formation of advanced glycation end products (AGEs), triggers oxidative impairments and influences inducible factor (HIF)-1α protein levels and transactivation function. Compromised HIF-1α in testis leads to male infertility. The aim of the study was to investigate the role of HIF-1α in oxidative stress induced by AGEs in murine Leydig TM3 cells. TM3 cells were treated with 50 μg/ml of AGEs, or HIF-1α siRNA or 500 μM of DMOG (dimethyloxalylglycine) respectively. The cells were also pretreated with HIF-1α siRNA or 500 μM of DMOG and then were treated with 50 μg/ml of AGEs. The formation of reactive oxygen species (ROS) and cell apoptosis was evaluated. The expression of caspase-3, Heme oxygenase (HO)-1, steroidogenic acute regulatory protein (StAR) and cytochrome P450 17α polypeptide 1 (CYP17A1) was examined by Western blotting. AGEs increased ROS production, induced apoptosis and activated HIF-1α and HO-1 in TM3 cells. HIF-1α attenuated the AGE-induced ROS formation and promoted apoptosis via the upregulation of caspase-3. Knockdown of HIF-1α inhibited the expression of CYP17A1 and StAR, and enhanced the inhibition of StAR and CYP17A1 by AGEs. These findings indicate that attenuated HIF-1α exacerbates the oxidative stress injury by AGEs in murine Leydig cells, and contributes to diabetic male infertility.     

Andrographolide down-regulates hypoxia-inducible factor-1α in human non-small cell lung cancer A549 cells

Andrographolide (Andro), a diterpenoid lactone isolated from a traditional herbal medicine Andrographis paniculata, is known to possess multiple pharmacological activities. In our previous study, Andro had been shown to inhibit non-small cell lung cancer (NSCLC) A549 cell migration and invasion via down-regulation of phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. Here we demonstrated that Andro inhibited the expression of hypoxia-inducible factor-1α (HIF-1α) in A549 cells. HIF-1α plays an important role in tumor growth, angiogenesis and lymph node metastasis of NSCLC. The Andro-induced decrease of cellular protein level of HIF-1α was correlated with a rapid ubiquitin-dependent degradation of HIF-1α, and was accompanied by increased expressions of hydroxyl-HIF-1α and prolyl hydroxylase (PHD2), and a later decrease of vascular endothelial growth factor (VEGF) upon the treatment of Andro. The Andro-inhibited VEGF expression appeared to be a consequence of HIF-1α inactivation, because its DNA binding activity was suppressed by Andro. Molecular data showed that all these effects of Andro might be mediated via TGFβ1/PHD2/HIF-1α pathway, as demonstrated by the transfection of TGFβ1 overexpression vector and PHD2 siRNA, and the usage of a pharmacological MG132 inhibitor. Furthermore, we elucidated the involvement of Andro in HIF-1α transduced VEGF expression in A549 cells and other NSCLC cell lines. In conclusion, these results highlighted the potential effects of Andro, which may be developed as a chemotherapeutic or an anti-angiogenesis agent for NSCLC in the future.     

Decreased carboxylesterases expression and hydrolytic activity in type 2 diabetic mice through Akt/mTOR/HIF-1α/Stra13 pathway

Abstract

• 1.?This study investigated the alteration of carboxylesterases in type 2 diabetes. We found that the carboxylesterase 1d (Ces1d) and carboxylesterase 1e (Ces1e) expression and the capacity of hydrolytic activity of liver and intestine decreased, whereas the Akt/mTOR/HIF-1α/ Stra13 (DEC1) signaling was activated in T2D mice. Consistently, high insulin could give rise to the same results in the high-glucose DMEM condition, which mimicked T2D, in primary mouse hepatocytes.

• 2.?Perifosine or rapamycin almost abolished the decrease of the Ces1d and Ces1e expression and the hydrolytic activity induced by the insulin in the primary mouse hepatocytes.

• 3.?The responsiveness of human hepatoma (HepG2) cells to high insulin in high-glucose condition was similar to that of primary mouse hepatocytes in terms of the altered expression of carboxylesterases.

• 4.?The knockdown of HIF-1α or DEC1 with shRNA construct abrogated the decrease of the CES1 and CES2 expression induced by the insulin in high glucose condition in HepG2 cells.

• 5.?Taken together, the decreased carboxylesterases expression and hydrolytic activity in T2D mice are through the Akt/mTOR/HIF-1α/Stra13 (DEC1) pathway.

     

Interleukin-2 maintains the survival of interleukin-17+ gamma/delta T cells in inflammation and autoimmune diseases

There is increasing appreciation of the critical pathogenic role of IL-17 in inflammation and autoimmune diseases, which could be produced from both adaptive Th17 cells and innate γδ T cells. Existing evidences suggest that IL-2 is important for in vivo accumulation of IL-17⁺ γδ T cells, leaving the mechanisms still elusive. Herein, using lupus-prone MRL/lpr mice, we demonstrated that splenic γδ T cells were potent IL-17 producers at the onset of lupus, which could be diminished by in vivo IL-2 neutralization. Additional in vivo results showed that neutralization of IL-2 also significantly deleted the IL-17-producing γδ T cells in ovalbumin (OVA) /CFA-immunized B6 mice. Using splenic γδ T cells from OVA/CFA-immunized B6 mice, we further demonstrated that IL-2 could induce IL-17 production alone or together with IL-1β or IL-23 or anti-TCRγδ. Mechanism studies demonstrated that IL-2 could support the survival of γδ T cells, rather than induce the proliferation. Through specific pharmacologic inhibitor, we demonstrated that IL-2 could maintain that RORγt expression of γδ T cells in a STAT5-dependent manner. Collectively, this study suggested that the interplay between IL and 2 and other pro-inflammatory cytokines could trigger the rapid IL-17 production from innate γδ T cells, thus to orchestrate an inflammatory response before the development of adaptive Th17 cells.     

姜黄素对人肝癌细胞BEL-7402中HIF-1α表达的影响

目的探讨姜黄素对人肝癌细胞BEL-7402中H IF-1α表达的影响以及蛋白酶体在其中的作用。方法以0、2.5、5、10、15、20μmol.L-1的姜黄素处理人肝癌细胞BEL-7402缺氧环境中培养6 h,W ST-8法和台盼蓝染色法分析细胞增殖和活力,采用RT-PCR和W estern B lot方法检测肝癌细胞中H IF-1α的表达;以0、10μmol.L-1姜黄素、10μmol.L-1MG-132、10μmol.L-1姜黄素+10μmol.L-1MG-132处理人肝癌细胞BEL-7402缺氧环境中培养6 h,采用W esternB lot方法检测肝癌细胞中H IF-1α的蛋白表达。结果①不同剂量的姜黄素对肝癌细胞活力和增殖率的影响与对照组相比差异无显著性;②随着姜黄素浓度的增加,H IF-1α蛋白表达逐渐降低;③不同剂量的姜黄素对H IF-1αmRNA表达的影响与对照组相比差异无显著性;④MG-132能够逆转姜黄素对H IF-1α蛋白的减少。结论姜黄素抑制人肝癌细胞BEL-7402中H IF-1α蛋白表达是通过转录后机制和蛋白酶体途径。     

Paeoniflorin suppresses IL-6/Stat3 pathway via upregulation of Socs3 in dendritic cells in response to 1-chloro-2,4-dinitrobenze

Mounting evidence has suggested that inflammation is associated with IL-6/Stat3 pathway in dendritic cells (DCs) and Th17 cells, which are critical for development of allergic contact dermatitis (ACD). Paeoniflorin (PF) has been clinically proved to be effective in the treatment of inflammatory skin diseases such as ACD. We have previously demonstrated the effect of PF on DCs stimulated with 1-chloro-2,4-dinitrobenze (DNCB) and naïve CD4⁺ CD45RA⁺ T cells for Th17 cell differentiation. However, whether PF down-regulates IL-6/Stat3 in DCs and Th17 cells remains to be explored. In this study, we show clearly that PF markedly decreases IL-6/Stat3 in DCs stimulated with DNCB at both gene and protein levels compared with control DCs in vitro. Meanwhile, PF up-regulates suppressor of cytokine signaling 3 (Socs3). Such decreased expression of IL-6/Stat3 is abolished in DCs that were transfected with Socs3 short interfering RNA (siRNA). When mice CD4⁺ CD45 RA⁺ T cells were co-cultured with PF-treated DCs stimulated with/without DNCB, the gene expression of the Th17 cell markers such as retinoic acid-related orphan nuclear hormone receptor γt (RORγt), IL-17A, and IL-23R decreased, in accordance with the less secretions of IL-17 and IL-23 in vitro and in vivo. Finally, the suppressed Th17 differentiation induced by PF can be abolished by additional recombinant mouse IL-6. Our results suggest that the anti-inflammatory mechanisms introduced by depletion of Socs3 expression or inactivation of the negative regulator such as Socs3 may represent a promising strategy for the prevention of ACD.     

甘草酸对慢性肾脏病大鼠心肌HMGB1/TLR4/NF-κB/HIF-1α信号通路的影响

目的 探讨应用甘草酸（Gly）治疗时对慢性肾脏病（CKD）大鼠心室肌高迁移率族蛋白B1/Toll样受体4/核因子κB/缺氧诱导因子1α(HMGB1/TLR4/NF-κB/HIF-1α)信号通路的影响。方法 将38只Wistar大鼠按随机数字表法分为4组：假手术（Sham）组、Sham+Gly组、CKD组、CKD+Gly组，5/6肾切除制备CKD模型，Gly腹腔注射给药（80 mg/kg）。4周后行血流动力学及心脏彩超观察各组大鼠心脏功能；心室取血检测生化指标；心肌组织取材检测HMGB1、TLR4、NF-κB、HIF-1α蛋白表达的变化。结果 与Sham组相比，CKD组肌酐、尿酸、尿素氮和血清镁水平增高（P<0.05），血压升高，舒张期室间隔厚度、收缩期左心室内径增加，左心室射血分数降低，E/A比值降低，肺动脉血流加速时间延长（P<0.05）;HE染色可见心肌细胞肥大，Masson染色见心肌纤维化程度增加（P<0.05），心肌组织HMGB1、NF-κB、HIF-1α蛋白表达水平上调（P<0.05）。与CKD组相比，CKD+Gly组收缩期室间隔厚度增加，左心室射血分...