组蛋白修饰变化参与曲古抑菌素A缓解的烟草烟雾暴露所致小鼠子宫损伤过程

目的研究组蛋白修饰变化在曲古抑菌素A(trichostatin A,TSA)缓解烟草烟雾(cigarette smoke,CS)暴露所致的雌性小鼠子宫损伤过程中的作用。方法通过CS暴露30 d方法制备CS暴露小鼠子宫损伤模型,CS暴露的同时给予TSA进行治疗;HE染色观察各组小鼠子宫组织形态学变化;Western blot技术检测各组小鼠子宫组织H3K4me1、H3K4me2、H3K4me3、H3K9me1、H3K9me2、H3K9me3和H3K27me3总的修饰水平变化以及GLP(euchromatic histone lysine methyltransferase 1,H3K9甲基转移酶),G9ɑ(euchromatic histone lysine methyltransferase 2,H3K9甲基转移酶),EZH2(enhancer of zeste homolog 2,H3K27me3甲基转移酶)的表达水平。结果TSA缓解CS暴露所致的雌性小鼠子宫间质细胞和腺体数量减少等结构改变。TSA有效抑制了CS暴露激活的小鼠子宫组织H3K9me1的表达,但却进一步激活CS暴露诱导的总H3K27me3修饰水平。TSA可以抑制CS暴露激活的小鼠子宫组织GLP和G9ɑ的表达,进一步激活CS暴露诱导的EZH2表达水平。结论组蛋白修饰变化参与CS暴露所致的小鼠子宫损伤以及TSA的缓解损伤过程。     

组蛋白乙酰化调控异常与大鼠抑郁行为的关系研究

目的研究组蛋白乙酰化与慢性不可预见刺激(chronic unpredictable stress,CUS)致大鼠抑郁行为的关系。方法30只♂Sprague Dawley(SD)大鼠随机分为对照组和模型组,采用孤养结合CUS方式连续刺激28 d建立大鼠抑郁症模型;以开场实验和强迫游泳实验评价大鼠抑郁行为;采用实时荧光定量PCR法检测大鼠前脑皮层和海马组蛋白去乙酰化酶2(histone deacetylase 2,HDAC2)mRNA表达;采用Western blot法检测大鼠前脑皮层和海马组蛋白H3(histone3,H3)、组蛋白H4(histone 4,H4)、乙酰化组蛋白H3(actylation-histone 3,ac H3)及乙酰化组蛋白H4(actylation-histone4,ac H4)蛋白表达水平。结果与对照组大鼠相比,模型组大鼠开场实验得分明显降低(P<0.01)、强迫游泳实验不动时间明显延长(P<0.01)、前脑皮层和海马HDAC2 mRNA和蛋白表达明显增加(P<0.01)、组蛋白H3和组蛋白H4蛋白表达均无明显差异、ac H3及ac H4蛋白水平均明显降低(P<0.01)。结论 CUS诱导大鼠产生抑郁样行为改变,其机制可能与脑内HDAC表达增高致组蛋白乙酰化修饰水平降低有关。     

TSA对不同糖浓度下小鼠海马神经元HT-22细胞凋亡的影响#br#

目的　探究曲古抑菌素A（TSA）对不同糖浓度下小鼠海马神经元细胞系HT-22细胞凋亡的影响。方法　分别用高糖培养基（葡萄糖浓度55 mmol/L）及普通培养基（葡萄糖浓度25 mmol/L）培养小鼠海马神经元HT-22细胞,高糖培养基及普通培养基各分为对照组（NC组）和抑制剂组（TSA组）。用1 mmol/L的TSA作用细胞1、4、8 h,同时用0.4 mmol/L的TSA作用细胞1、4、8、12、14、16、20、24 h,CCK8法检测细胞存活率,确定抑制剂最佳作用浓度和作用时间;酶联免疫吸附测定（ELISA）法检测组蛋白去乙酰化酶（HDAC）和组蛋白乙酰转移酶（HAT）活性;流式细胞术检测细胞凋亡情况;蛋白免疫印迹法检测B淋巴细胞瘤-2（Bcl-2）、Bcl-2相关X蛋白（Bax）、半胱氨酸天冬氨酸蛋白酶3（Caspase-3）的表达情况。结果　以0.4 mmol/L、20 h为TSA处理HT-22细胞的最适条件;ELISA结果显示,TSA作用后,HDAC显著减少,HAT显著增加（P＜0.05）;流式细胞术结果显示,在TSA抑制20 h后,细胞凋亡率显著增加,高糖环境下加入TSA,细胞凋亡情况更加严重;TSA作用20 h后,Bcl-2表达显著下调,Caspase-3显著上调（P＜0.05）。结论　TSA可能通过抑制HDAC增加组蛋白乙酰化水平,导致小鼠神经元HT-22细胞的凋亡。     

组蛋白赖氨酸甲基转移酶2B的研究进展

组蛋白赖氨酸甲基转移酶2B（histone lysine-K specific methyltransferase 2B,KMT2B）,也称为混合谱系白血病2（mixed lineage leukemia 2,MLL2）蛋白,属于哺乳动物组蛋白H3赖氨酸4（histone H3 lysine-K 4,H3K4）特异性的甲氨基转移酶家族,在广泛的细胞过程中发挥关键作用。KMT2B蛋白本身及其介导转录的某些特定基因启动子、强化子或附近顺式调节位点上的H3K4甲基化（H3K4me）的修饰,均能引起表观遗传修饰异常的改变,从而通过调控基因的转录与表达进而影响生长、发育。随着国内外近年来对KMT2B蛋白研究进一步的深入,发现KMT2B与早期生长迟缓、胚胎死亡、自主运动的控制和儿童肌张力障碍的发病机制有关。此外,MLL家族的MLL2在肝细胞癌、白血病、结肠直肠癌和神经胶质瘤等肿瘤里高表达,表现出有促肿瘤功能。在这篇综述中,我们讨论了KMT2B基因、KMT2B蛋白特征和生物学功能,还强调了基因调控、组织发育、先天性疾病和肿瘤疾病的影响,以期为相关疾病预防和诊治提供新的思路。     

H3K27me3在肿瘤中的表达及其应用

组蛋白H3第27位赖氨酸三甲基化(H3K27me3)的修饰是表观遗传中重要的基因沉默标志,参与调节细胞分化与增殖之间的平衡,其表达水平异常与多种疾病密切相关.H3K27me3由多梳抑制复合物2(PRC2)产生,PRC2组成部分的改变,如Zeste基因增强子人类同源物2(EZH2)功能改变或过表达、胚胎外胚层发育蛋白(E...     

甲基转移酶SETDB2对肝癌侵袭迁移的影响及其机制研究

摘要：目的 检测甲基转移酶SETDB2对肝癌侵袭转移的影响并探讨其机制。方法 应用Western blot、免疫组 化以及 Real-time PCR 等方法检测 37 例肝癌及对应癌旁组织标本中 SETDB2 蛋白及 mRNA 表达情况。将靶向 SETDB2 的短发卡 RNA（sh-SETDB2）和空载体（sh-NC）分别转染至人肝癌 MHCC97H 细胞构建稳转细胞系,应用 Tanswell侵袭实验、细胞划痕实验检测2组细胞的侵袭和迁移能力。通过基因芯片检测敲低SETDB2后表达有变化 的基因。敲低SETDB2后,运用Real-time PCR检测PTEN的mRNA的表达变化以及Western blot检测PTEN和组蛋白 H3第9位赖氨酸的三甲基化（H3K9me3）的表达变化,CHIP 检测H3K9me3在PTEN 的启动子区域的变化。在敲低 SETDB2的同时敲低PTEN的表达,Tanswell侵袭实验检测细胞侵袭能力的变化。结果 （1）Western blot和Real-time PCR的结果均表明肝癌组织中SETDB2蛋白及mRNA表达水平均高于癌旁组织;SETDB2表达的高低与肝癌组织学 分级和TNM分期有关。（2）转染sh-SETDB2的MHCC97H细胞的侵袭和迁移能力均明显低于sh-NC组。（3）基因芯 片、Western blot以及Real-time PCR等实验结果显示敲低SETDB2后PTEN表达上调。（4）在敲低SETDB2后H3K9me3 表达下调,PTEN启动子区域的H3K9me3减少。（5）与敲低SETDB1组相比,敲低SETDB2的同时敲低PTEN后细胞的 侵袭能力恢复。结论 SETDB2通过下调PTEN的表达促进肝癌细胞的侵袭迁移。     

甘珀酸抑制eATP-P2X7R-NLRP3信号通路减轻慢性胰腺炎纤维化的实验研究

摘要：目的　探讨细胞外ATP（eATP）-P2X7R-NLRP3信号通路在慢性胰腺炎（CP）胰腺纤维化中的作用以及ATP抑制剂甘珀酸（CBX）对CP的治疗作用。方法　将6周龄雄性C57BL/6小鼠随机均分为5组：正常组,模型组,CBX低、中、高剂量组（分别为25、50、100 mg/kg）。造模结束后,CBX各剂量组小鼠分别腹腔注射相应剂量的药物。末次给药24 h后将小鼠脱颈处死。HE染色评估胰腺组织病理学改变;ATP化学发光法测定小鼠胰腺组织eATP水平;免疫荧光染色检测P2X7R、NLRP3、半胱氨酸天冬氨酸蛋白酶1（Caspase-1）蛋白表达;实时荧光定量逆转录聚合酶链反应（qPCR）检测P2X7R、NLRP3、Caspase-1、缝隙连接蛋白（PAN-1）mRNA的表达。结果　HE染色,光镜下可见正常组小鼠胰腺细胞分布紧密,排列规则,无纤维化及炎症细胞浸润。模型组细胞间隙增宽、腺泡萎缩、炎症细胞浸润且有大量胶原纤维生成,组织学评分较正常组显著升高（P＜0.01）;与模型组相比,CBX中、高剂量组炎症细胞浸润及胶原纤维生成均减少,组织学评分降低。模型组小鼠造模后eATP水平较正常组显著升高（P＜0.01）,CBX中、高剂量组给药2周后,胰腺组织eATP水平均低于模型组。免疫荧光染色法和qPCR检测均显示,与正常组相比,模型组P2X7R、NLRP3、Caspase-1蛋白和mRNA表达升高（P＜0.01）;与模型组相比,CBX中、高剂量组表达均下调（P＜0.05）。此外,qPCR检测结果还显示,模型组小鼠PAN-1 mRNA表达较正常组显著上调;与模型组相比,CBX中、高剂量组表达均下调（P＜0.01）。结论　CP病程中eATP水平显著增加并激活P2X7R,促进NLRP3炎性体组装,加重胰腺纤维化,CBX可下调P2X7R、NLRP3、Caspase-1,减轻胰腺炎症损伤及纤维化,从而发挥治疗作用。     

TSA抑制NB4细胞去乙酰化酶活性并促进细胞周期素激酶抑制剂表达

目的　研究曲古菌素A(TrichostatinA,TSA)对NB4细胞组蛋白去乙酰化酶HDAC1的作用及细胞周期依赖激酶抑制剂P21WAF1 /CIP1的表达,探讨TSA抗白血病的作用机制。方法　培养人的急性早幼粒细胞白血病细胞株NB4,应用TSA在不同浓度和不同时间点处理细胞,提取细胞的总蛋白和mRNA,用Westernblot蛋白质印迹技术检测HDAC1和P21WAF1 /CIP1 蛋白表达, 并用RT PCR技术同时检测P21WAF1 /CIP1 mRNA的表达水平。结果　①TSA明显抑制HDAC1的活性和表达,在IC50浓度时作用 4hHDAC1已经降低,持续 48 h;在较低浓度 ( 37 5 nmol·L-1 )时就对HDAC1有明显的抑制作用,但在 75 ~ 300 nmol·L-1时HDAC1降低水平未见明显区别;②TSA明显促进P21WAF1 /CIP1蛋白和mRNA的表达,在 8h时mRNA已增高, 12h后可见到蛋白增加,在浓度大于 150nmol·L-1时呈明显时间和剂量依赖性。结论　TSA明显抑制HDAC1活性和表达,促进细胞周期依赖性激酶抑制剂P21WAF1 /CIP1蛋白和mRNA水平升高,有明显的抗白血病作用。抑制HDAC1活性和促进P21WAF1 /CIP1增加可能是TSA抗白血病的机制之一。     

热打击通过活化NLRP3炎性小体增加肺毛细血管的通透性

目的 验证热打击通过活化 NLRP3炎性小体增加肺毛细血管通透性的机制。方法 C57BL/6小鼠和肺微血管内皮细胞,用 42 ℃热打击。体内实验分组包括：对照组和热打击组,每组 12只小鼠;体外实验分组包括：对照组、热打击组、热打击+2,2,6,6-四甲基哌啶氧化物（TEMPO）组、热打击+半胱氨酸的天冬氨酸蛋白水解酶（caspase）抑制剂（Z-VAD-FMK）组、热打击+白细胞介素-1受体拮抗剂（IL-1Ra）组,每组 4例。检测肺组织和肺微血管内皮细胞活性氧（ROS）表达;Western blot 和（或）免疫荧光检测 caspase-1、白细胞介素-1β（IL-1β）、紧密连接蛋白 ZO-1、occludin、claudin-5的表达;用伊文氏蓝检测小鼠肺毛细血管的通透性。结果 体内实验结果显示,与对照组比较,热打击组小鼠肺组织伊文氏蓝浓度明显升高、ROS表达上调、NLRP3炎性小体活化、IL-1β表达上调和紧密连接蛋白的表达下调（P＜0.01）。体外实验结果显示,用 TEMPO 清除 ROS 后,NLRP3炎性小体活化被抑制（P＜0.01）;用 ZVAD-FMK抑制 caspase-1作用后,IL-1β表达显著下调（P＜0.01）;用 IL-1Ra阻断 IL-1β作用后,紧密连接蛋白表达显著上调（P＜0.01）。结论 热打击可通过活化 NLRP3炎性小体促进 IL-1β的表达,进而下调紧密连接蛋白的表达,导致肺微血管通透性增加。     

Trichostatin A alleviated ovarian tissue damage caused by cigarette smoke exposure

Cigarette smoke (CS) has a negative impact on women's health and fertility. Studies have shown that histone deacetylases 1 and 2 (HDAC1/2) were involved in oocyte development. However, the roles of HDAC1/2 in ovarian toxicity caused by CS exposure and the therapeutic potential of trichostatin A (TSA, a HDAC inhibitor) for ovarian tissue damage have not been investigated. In this study, Female C57BL/6 mice were exposed to CS from six cigarettes mixed with indoor air for 120 min (one cigarette for 20 min) using a whole-body mainstream smoke exposure system twice daily for 30 days. TSA (0.6 mg/kg body weight) was injected intraperitoneally into mice in the Control + TSA group and CS + TSA group every two days for 30 days. We found that exposure to CS resulted in ovarian tissue damage and HDAC1/2 over-expression. TSA alleviated the structural changes of ovarian tissue induced by smoking and prevented the activation of HDAC1/2. Exposure to CS caused autophagy inhibition and pyroptosis activation. TSA treatment restored the expression of autophagy-associated proteins and decreased the levels of pyroptosis-related proteins induced by CS exposure. The TSA effect may be mediated by inhibition of HDAC1/2 involved in autophagy and pyroptosis process.     

PI3K/AKT信号通路在大鼠腹腔感染性脓毒症急性肾损伤中的作用

目的 探究磷脂酰肌醇3-激酶/蛋白激酶B（PI3K/AKT）信号通路在大鼠腹腔感染性脓毒症急性肾损伤（acute kidney injury,AKI）中的作用。方法 使用盲肠结扎穿孔（cecal ligation and puncture,CLP）的方法制备大鼠腹腔感染性脓毒症模型,按照检测时间点（24、48、72 h）分组,于术后各时间点用全自动生化分析仪检测血清肌酐（Cr）、尿素氮（BUN）水平;用实时定量聚合酶链反应（Real-time PCR）检测大鼠肾脏组织PI3K mRNA及AKT mRNA的表达水平,采用蛋白免疫印迹法（Western blot,WB）检测大鼠肾脏组织Nod样受体蛋白3（NLRP3）、凋亡相关斑点样蛋白（ASC）、半胱氨酸天冬氨酸特异性蛋白酶1（Caspase-1）蛋白表达水平,采用酶联免疫吸附法（ELISA）检测血清肿瘤坏死因子-α（TNF-α）、白细胞介素（IL）-1β及IL-18的表达水平。假手术组除不进行盲肠结扎及穿孔外,其余操作与CLP组相同。结果 与假手术组相比,CLP各组大鼠血Cr、BUN水平出现明显升高（P＜0.05）,肾脏组织内PI3K及AKT mRNA 表达水平明显升高（P＜0.01）,且其下游 NLRP3 炎性小体蛋白表达水平明显升高（P＜0.01）,同时血清TNF-α、IL-1β及IL-18水平明显升高（P＜0.01）。结论 PI3K/AKT信号通路在腹腔感染性脓毒症AKI中具有重要作用,其活化诱导下游NLRP3炎性小体活化增加,进而使炎症因子释放增加并加重脓毒症病情。     

Effect of the histone deacetylase inhibitor trichostatin A on spontaneous apoptosis in various types of adult rat hepatocyte cultures

Acetylation and deacetylation of histones, catalysed by histone acetyl transferases and histone deacetylases (HDAC), respectively, are known to be involved in gene expression regulation. Here, the effect on the activity and expression of several apoptosis-related proteins of trichostatin A (TSA), a well-known HDAC inhibitor, were studied in short-term (conventional monolayer) and long-term cultured (collagen I gel sandwich cultures and co-cultures) adult rat hepatocytes. No significant effects of TSA on the caspase-3-like activity were seen in rat hepatocytes cultured in a sandwich configuration or in a co-culture with rat liver epithelial cells of primitive biliary origin. In both culture models, the basal level of apoptosis was found to be much lower than in control monolayer cultures. In the latter system, it was found that, after 4 days of culture, TSA decreased the levels of caspase-3 (both proform and p17 fragment) and of the pro-apoptotic protein Bid. No effect of TSA was found on the expression of Bax. As expected, a TSA-mediated increase of acetylated histones H3 and H4 was observed in all culture systems examined. In addition, in the presence of TSA, increased albumin secretion and cytochrome P450 1A1/2 and 2B1-dependent enzyme activities were found in conventional cultures after 7 days. In conclusion, TSA delayed the occurrence of apoptosis and loss of liver specific functions in conventional hepatocyte monolayers. In contrast, in hepatocyte culture models in which spontaneous apoptosis is already minimised through the addition of either extracellular matrix components (sandwich cultures) or non-parenchymal liver cells (co-cultures), TSA did not have any additional anti-apoptotic effect.     

Arsenite downregulates H3K4 trimethylation and H3K9 dimethylation during transformation of human bronchial epithelial cells

Arsenic is an established human carcinogen but with weak mutagenic activity. The mechanisms of arsenic‐induced carcinogenesis are not well understood. In the present study, we investigated the role of histone methylation in transformation of human bronchial epithelial (BEAS‐2B) cells. After 16 weeks’ exposure, cells were transformed by 0.1, 0.5 and 1 μm arsenite. Global trimethylated H3K4 (H3K4me3) was decreased by 0.1 μm arsenite at 12 weeks, and 0.5 and 1 μm arsenite at 8, 12 and 16 weeks, which could be attributed to reduced histone methyltransferase activities, increased histone demethylase (HDM) activities as well as increased protein levels of H3K4 demethylase KDM5A. Global dimethylated H3K9 (H3K9me2) was also decreased after exposure to 0.5 μm arsenite for 4, 8, 12 and 16 weeks and 1.0 μm arsenite for 8 and 12 weeks, which was associated with an increase of HDM activities. Our findings indicated that arsenite decreased global H3K4me3 and H3K9me2 levels during cell transformation by modulating the enzymatic activities of histone methyltransferases and/or HDMs, and by upregulation of KDM5A protein levels for H3K4me3.