长期能量限制增加去乙酰化酶SIRT1表达和降低小鼠血管的衰老

目的 初步研究能量限制对血管细胞衰老的影响及作用机制。方法 取2月龄和18月龄的C57BL/6小鼠,用western blot检测血管细胞衰老分子相关分子的变化;建立能量限制12月的小鼠模型,用western blot检测相关分子的蛋白水平。结果 与2月龄小鼠相比,18月龄的小鼠动脉中SIRT1表达水平显著降低。能量限制显著增加小鼠动脉中SIRT1表达水平,降低细胞衰老标志分子P53和P21表达水平,增加抗氧化酶MnSOD的表达水平。结论 能量限制可以抑制血管细胞衰老,其机制可能与增加SIRT1表达,降低氧化应激有关。     

能量限制条件下SIRT1和SIRT2的表达变化

目的研究不同程度的能量限制（CR）下,大鼠脑组织中SIRT1和SIRT2的表达变化。方法 60只大鼠随机分成四组：正常对照组、75%CR组（喂养食物为正常对照组的75%）,55%CR组（喂养食物为正常对照组的55%）和高脂组,喂养8周。免疫组织化学检测大鼠脑组织中SIRT1和SIRT2的表达与定位。RT-PCR及Western-blot检测各实验组中SIRT1、SIRT2的表达。结果在大鼠脑组织中发现SIRT1可于细胞浆和细胞核中表达,且主要于细胞核中表达;SIRT2主要在细胞核中表达。能量限制下,与对照组相比SIRT1表达升高;高脂食物条件下,SIRT1表达相对于对照组增高,但是比CR组减少。75%CR与55%CR相比,后者中的SIRT1的表达增加更多。与对照组相比,55%CR增加SIRT1的表达差异有统计学意义（P〈0.05）,而75%CR和HFa增加SIRT1的表达差异无统计学意义。SIRT2在CR和HFa下表达无明显变化。结论 CR能增加SIRT1而不增加SIRT2的表达,重度CR比中等程度CR对SIRT1表达的影响更大。     

IRF3 and IRF7 contribute to diesel exhaust particles-induced pulmonary inflammation by mediating mTORC1 activation and restraining autophagy in mice

Exposure to diesel exhaust particles (DEPs) is associated with acute inflammatory responses in the lung and exacerbation of respiratory diseases. However, the mechanism by which DEPs trigger the inflammatory responses remains unclear. Here, we demonstrated that the IFN response factors IRF3 and IRF7 played pivotal roles in DEP-induced pulmonary inflammation. DEPs could not directly induce inflammatory cytokine expression in mouse cells, whereas DEPs triggered autophagy both in vitro and in vivo. The DEP-induced autophagy was augmented in the absence of IRF3 and IRF7, but not in the absence of IFNAR. The expression of Raptor was induced by IRF3 and IRF7 in response to DEPs treatment. Furthermore, administration of the mechanistic target of rapamycin (mTOR) inhibitor alleviated the inflammatory responses in the lung during DEP exposure. Our findings define an IFNAR-independent role of increased autophagy in the absence of IRF3 and IRF7 during pulmonary DEP exposure, and provide the basis to develop new therapeutic approaches to counteract the adverse effects of DEPs and possibly other ambient particulate matters.     

SIRT1过表达可抑制衣霉素诱导软骨细胞内质网应激

目的探究SIRT1对衣霉素诱导的软骨细胞内质网应激的影响。方法分离人正常软骨细胞和骨关节炎(OA)软骨细胞,观察细胞形态,免疫细胞化学染色检测Ⅱ型胶原表达,Western blot检测SIRT1表达。将培养的软骨细胞分为对照组(OA软骨细胞、正常软骨细胞)、正常软骨细胞组(衣霉素组、SIRT1过表达组和衣霉素+SIRT1过表达组)。24 h后,Western blot检测ERS相关蛋白(CHOP、p-e IF2α和ATF4等)、凋亡相关蛋白(Bcl-2、Bax和caspase-3等)以及p-P38的表达。ELISA检测NF-κB活性。结果与人正常软骨细胞相比,OA软骨细胞增殖缓慢,Ⅱ型胶原和SIRT1表达均显著降低(P0.05)。与正常软骨细胞对照组相比,OA对照组和0.5 mg/L衣霉素组CHOP、p-e IF2α、ATF4和p-P38表达上调,NF-κB活性增加,Bcl-2表达明显下调,Bax和caspase-3表达明显增加(P0.05)。SIRT1过表达处理则显著逆转上述蛋白表达。结论 SIRT1过表达可抑制衣霉素诱导的软骨细胞内质网应激和细胞凋亡,并下调P38/NF-κB活化。     

Tumor-associated macrophages expressing the transcription factor IRF8 promote T cell exhaustion in cancer

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Altered expression of transcription factors IRF4 and IRF8 in peripheral blood B cells is associated with clinical severity and circulating plasma cells frequency in patients with myasthenia gravis

Previous studies have shown that interferon regulatory factor-4 (IRF4) and IRF8 play critical but distinct roles in the differentiation of B cells into plasma cells (PCs). In the present study, we aimed to measure the expression levels of IRF4 and IRF8 in B cells from patients with myasthenia gravis (MG) and to investigate whether the expression of IRF4 and IRF8 associates with pathogenesis of MG. A total of 35 anti-acetylcholine receptor (AChR) antibody (Ab)-positive patients with MG [20 generalized MG (GMG) and 15 ocular MG (OMG) and 25 healthy donors were recruited in this study. The quantitative myasthenia gravis score (QMGS) was used to evaluate the clinical severity. Real-time PCR and Western blot were used to measure the levels of IRF4 and IRF8 expressed in peripheral blood B cells. Peripheral blood CD138⁺ PCs were assayed by flow cytometry. Our data demonstrated that the mRNA/protein levels of IRF4 and IRF8 were significantly higher and lower, respectively, in patients with OMG/GMG groups compared with healthy controls. In addition, IRF4 expression was significantly higher and IRF8 expression was significantly lower in GMG group than in OMG group. Pearson’s correlation analysis revealed that IRF8 expression was negatively correlated with clinical severity, PCs frequency and anti-AChR Ab levels, while IRF4 expression and IRF4/IRF8 ratio was positively correlated with these parameters in two MG subgroups. Finally, glucocorticoid treatment can relieve the imbalance of IRF4/IRF8 in peripheral blood B cells, and this restoration is accompanied by reduced PCs frequency and clinical symptoms. These evidences suggest that IRF4 and IRF8 are important in the counter-balancing mechanisms controlling differentiation of PCs in MG. The disruption of the balanced IRF4/IFR8 ratio in B cells may play important roles in the pathogenesis of MG and offer a promising therapeutic target for the development of novel immunotherapy for MG patients.     

IRF1对M1巨噬细胞极化及其抗肿瘤效应的影响

目的研究IRF1对M1巨噬细胞极化及M1介导的抗肝癌细胞增殖和凋亡的影响。方法构建单核细胞U937来源M1巨噬细胞模型(U937-M1),将细胞分为4组:用PMA诱导的未活化巨噬细胞组(M0),用PMA,IFN-γ和LPS处理的M1型巨噬细胞组(M1),用siRNA干扰IRF1的M1型巨噬细胞组(si IRF1)以及阴性干扰的M1型巨噬细胞组(si C)。用流式细胞术检测M1/M2特异表面标志物CD86/CD206的表达;q PCR检测M1/M2相关基因(IL-12p35,IL-12p40,IL-23p19,IL-6,TNF-α/IL-10)及IFNB1的表达;ELISA检测IL-12p70,IL-10及IFN-β的表达;Western blot检测IRF1及IRF5的表达;CCK8和流式细胞术分别检测Hep G2及SMMC-7721增殖和凋亡。结果与U937-M1组相比,干扰IRF的M1组CD86表达降低,但CD206升高(P0.05);mRNA水平上,IL-12p35,IL-12p40,IL-23p19,IL-6,TNF-α以及IFNB1表达降低,但IL-10表达增高(P0.01);蛋白水平上,IL-12p70,IFN-β及IRF5表达降低,但IL-10表达增高(P0.05)。IRF1干扰后,M1巨噬细胞促进肝癌细胞增殖、抑制其凋亡(P0.05)。结论干扰IRF1后,M1巨噬细胞极化状态受损,甚至部分向M2型转变;其抗肿瘤效应转变为促肿瘤效应;且IRF1可能参与调节IFN-β与IRF5的表达。     

SIRT1 promotes proliferation and inhibits apoptosis of human malignant glioma cell lines

In mammalian cells, SIRT1 decreases PTEN acetylation and inactivates the AKT pathway in a SIRT1 deacetylase-dependent manner. However, the function of SIRT1 in glioma was unknown. SIRT1 reexpression or knockdown was induced in human glioma cell lines. The cell synchronization, BrdU labeling and mitotic index were detected. Subsequently, cell cycle, cell viability, apoptosis, cell growth and proliferation were analyzed. Our work identified that SIRT1-knockdown significantly delayed mitotic entry of glioma cells, inhibited its growth and proliferation, and promoted its apoptosis. The apoptosis was related to PTEN/PI3K/AKT signaling pathway. The results showed that SIRT1 might be a promoter factor on tumorigenesis of glioma through PTEN/PI3K/AKT signaling pathway.     

IRF8 deficiency induces the transcriptional,functional, and epigenetic reprogramming of cDC1 into the cDC2 lineage

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SIRT1上调大鼠血管平滑肌细胞P27Kip1的表达

目的 研究III类去乙酰化酶SIRT1在血管平滑肌中对p27Kip1表达的影响及其可能的机制。方法 用H2O2和oxLDL刺激大鼠平滑肌细胞A7r5,Western blot检测平滑肌细胞内源性SIRT1的表达变化;在动物血管损伤模型中,Western blot检测血管损伤处平滑肌的SIRT1表达水平。用SIRT1重组腺病毒感染A7r5细胞和原代大鼠平滑肌细胞,Western blot观察SIRT1过表达引起的p27表达的改变;用SIRT1抑制剂NAM处理平滑肌细胞并观察p27的表达改变;用免疫共沉淀技术探寻SIRT1上调p27基因表达可能的分子机制。 结果 在H2O2和oxLDL氧化应激刺激的A7r5细胞中,内源性SIRT1的表达随作用时间逐渐增加;动物血管损伤模型中,内源性SIRT1的表达明显上调;过表达SIRT1能够在10%血清刺激的早期上调p27表达,而SIRT1抑制剂NAM则能够减少p27表达;在原代平滑肌细胞中,腺病毒介导的SIRT1过表达同样能够显著上调p27的表达。在血管平滑肌细胞中检测到SIRT1能够与FOXO3a相互作用。结论 SIRT1在血管平滑肌细胞中上调p27的表达。     

Acacia ferruginea inhibits inflammation by regulating inflammatory iNOS and COX-2

Inflammation is a local defensive reaction of a host to cellular injury or infection. Prolonged inflammation can contribute to pathogenesis of many disorders. Identification of naturally occurring phytoconstituents that can suppress inflammatory mediators can lead to the discovery of anti-inflammatory therapeutics. Acacia ferruginea is used traditionally to treat numerous ailments including hemorrhage, irritable bowel syndrome and leprosy. The present study evaluated the anti-inflammatory activity of A. ferruginea extract against acute (carrageenan) and chronic (formaldehyde) inflammation in Balb/c mice. Pre-treatment with A. ferruginea extract (10?mg/kg BW) for 5 consecutive days via intraperitonial (IP) administration significantly inhibited subsequent induction of paw edema in both models; the effects were comparable to that of the standard drug indomethacin. The results also showed the A. ferruginea extract significantly inhibited nitric oxide (NO) synthesis and iNOS expression (as measured in serum), diminished inflammation in – and neutrophil infiltration to – the paw tissues and led to a reduction in the number of COX-2⁺ immunoreative cells (as evidenced by histologic and immunohistochemical analyses) in the paws relative to those in paws of mice that received the irritants only. Further, in vitro studies showed the extract could significantly scavenge free radicals generated as in DPPH and NO radical generating assays. Taken together, the results showed that A. ferruginea extract imparted potent anti-oxidant and -inflammatory effects, in part by maintaining oxidative homeostasis, inhibiting NO synthesis and suppressing iNOS and COX-2 expression and so could potentially be exploited as a potential plant-based medication against inflammatory disorders.     

Induction of iNOS expression and antimicrobial activity by interferon (IFN)-beta is distinct from IFN-gamma in Burkholderia pseudomallei-infected mouse macrophages

Burkholderia pseudomallei is a causative agent of melioidosis. This Gram-negative bacterium is able to survive and multiple inside both phagocytic and nonphagocytic cells. We previously reported that exogenous interferons (both type I and type II) enhanced antimicrobial activity of the macrophages infected with B. pseudomallei by up-regulating inducible nitric oxide synthase (iNOS). This enzyme thus plays an essential role in controlling intracellular growth of bacteria. In the present study we extended our investigation, analysing the mechanism(s) by which the two types of interferons (IFNs) regulate antimicrobial activity in the B. pseudomallei-infected macrophages. Mouse macrophage cell line (RAW 264.7) that was exposed simultaneously to B. pseudomallei and type I IFN (IFN-beta) expressed high levels of iNOS, leading to enhanced intracellular killing of the bacteria. However, neither enhanced iNOS expression nor intracellular bacterial killing was observed when the macrophages were preactivated with IFN-beta prior to being infected with B. pseudomallei. On the contrary, the timing of exposure was not critical for the type II IFN (IFN-gamma) because when the cells were either prestimulated or co-stimulated with IFN-gamma, both iNOS expression and intracellular killing capacity were enhanced. The differences by which these two IFNs regulate antimicrobial activity may be related to the fact that IFN-gamma was able to induce more sustained interferon regulatory factor-1 (IRF-1) expression compared with the cells activated with IFN-beta.     

胃癌组织中SIRT1、Noxa的表达及其临床意义

目的探讨SIRT1与Noxa在胃癌组织中的表达水平相关性,分析两者表达与患者临床病理学特征及预后的关系。方法应用实时荧光定量PCR法和免疫组化EnVision两步法检测106例胃癌及癌周正常组织中SIRT1及Noxa的mRNA和蛋白表达,分析两者相关性及其与患者性别、年龄、肿瘤部位、肿瘤大小、浸润深度及转移等临床病理特征的关系。结果实时荧光定量PCR结果显示,胃癌组织中SIRT1 mRNA表达较高,Noxa mRNA表达较低。免疫组化结果显示,SIRT1在胃癌组织中的阳性率高于正常胃组织(79.2%vs 41.5%),Noxa在胃癌组织中的阳性率低于正常胃组织(43.3%vs 71.6%),差异有统计学意义(P0.05)。SIRT1表达与肿瘤分化程度、肿瘤直径、浸润深度、淋巴结和远隔器官转移情况相关(P均0.05),Noxa表达与肿瘤直径、浸润深度、淋巴结和远隔器官转移情况相关(P均0.05)。胃癌组织中SIRT1与Noxa表达呈负相关。SIRT1阳性、Noxa阴性的患者2年生存率较低,其是预后较差的独立危险因素。结论 SIRT1和Noxa在胃癌的发生、发展中可能具有协同作用,联合检测两者的表达有助于判断患者的临床表现和预后。     

组蛋白脱乙酰酶SIRT1与细胞自噬

.Sirtuin 1 (SIRT1), one of the nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylases, plays an important role in regulating cell cycle, cell aging, apoptosis and metabolism. Autophagy, a vital basic phenomenon that wildly exists in eukaryotic cells, plays an important part in waste scavenging, structure reestablishment, growth and development. In recent years, more and more attention has been paid to the connection between SIRT1 and autophagy. Clarifying the relationship between SIRT1 and autophagy will be of great importance in preventing and controlling aging-related diseases. This article overviews its research advancement.     

SIRT1在乳腺癌中的作用

沉默信息调节因子1(sirtuin Type 1,SIRT1)是酵母Sir2的哺乳动物同源体,是一种NAD+依赖的Ⅲ类组蛋白去乙酰化酶,能使组蛋白和非组蛋白去乙酰化,参与细胞多种生理、病理过程,如基因沉默、细胞衰老、寿命延长、抗氧化应激、能量代谢调节、DNA损伤修复、肿瘤发生等。其中,SIRTl在乳腺癌的发生中涉及的上下游信号分子众多,信号通路繁杂而交叉。有研究显示SIRTl起着抑制乳腺癌发生的作用;而有的研究结果正相反,SIRTl起着促进乳腺癌发生的作用。