Objective:To explore the molecular mechanism of the effect of the histone methylase zeste gene enhancer homolog 2 (EZH2) on the proliferation and apoptosis of human hypertrophic cardiomyocytes AC16.Methods:The AC16 hypertrophic cardiomyocyte model was constructed by adding angiotensin Ⅱ to the AC16 cell culture medium. The cells were divided into four groups, including the blank control group, the angiotensin Ⅱ group, the empty vector + angiotensin Ⅱ group, and the EZH2 overexpression + angiotensin Ⅱ group. The expression levels of EZH2 and brain natriuretic peptide ( BNP) genes were measured using fluorescent quantitative PCR. The EZH2, trimethylation of lysine at position 27 of histone H3 (H3K27me3), and BNP proteins expression were detected by Western Blot. The MTS method was used to detect the proliferation of AC16 cell. The Annexin V-FITC/PI double staining method was used to detect the apoptosis of AC16 cell. Results:Compared with the blank control group, the expression levels of EZH2 and H3K27me3 in the angiotensin Ⅱ group were decreased, the expression level of BNP was increased, cell proliferation was decreased, and apoptosis was increased (all P < 0.001). Compared with the empty vector + angiotensin Ⅱ group, the expression levels of EZH2 and H3K27me3 in the EZH2 overexpression + angiotensin Ⅱ group were increased, the expression level of BNP was decreased, the cell proliferation level was increased, and the apoptosis level was decreased (all P < 0.001). There was no significant difference between the angiotensin Ⅱ group and the empty vector + angiotensin Ⅱ group (all P > 0.05). Conclusions:Histone methylase EZH2 has an effect on the proliferation and apoptosis of AC16 cell, providing a reference for the treatment of myocardial hypertrophy and revealing the exact pathogenesis of myocardial hypertrophy.

目的 观察心肌肥厚大鼠心肌组织及肥大心肌细胞中环状RNA rno_circRNA_016002的表达变化,并探讨其在心肌肥厚过程中的作用.方法 将12只SD大鼠随机分为Control组与异丙肾上腺素(ISO)组,每组6只.ISO组每天腹腔注射ISO 3 mg/kg,Control组注射同等体积的生理盐水,连续注射两周后采用心脏超声检测心肌以明确心肌肥厚大鼠模型建立,然后处死大鼠,取出心脏组织,利用实时定量PCR法检测心肌组织中环状RNA rno_circRNA_016002.将心肌细胞H9C2饥饿过夜后分为ISO 50μmol/L与ISO 100μmol/L组、细胞对照组,ISO 50μmol/L与ISO 100μmol/L组中分别添加50与100μmol/L的ISO进行心肌肥厚的诱导,细胞对照组不作处理,利用实时定量PCR法检测肥大心肌细胞H9C2中环状RNA rno_circRNA_016002;将心肌细胞H9C2分为siRNA+ISO 50μmol/L组、siRNA+ISO 100μmol/L组、siRNA组、阴性对照组,其中siRNA+ISO 50μmol/L与siRNA+ISO 100μmol/L组加入siRNA与转染试剂后,分别再加入50与100μmol/L的ISO处理饥饿过夜;阴性对照组中只加入转染试剂,siRNA组中加入siRNA与转染试剂.加入ISO 48 h后利用实时定量PCR法检测各组心肌细胞H9C2中ANP mRNA与BNP mRNA,采用Western blotting检测各组心肌细胞H9C2中ANP、BNP蛋白质.结果 与Control组比较,ISO组环状RNA rno_circRNA_016002的表达水平上调(P<0.01);与细胞对照组比较,ISO 50μmol/L、ISO 100μmol/L组环状RNA rno_circRNA_016002的表达水平均上调(P均<0.01).siRNA+ISO 50μmol/L与siRNA+ISO 100μmol/L组中ANP、BNP mRNA和蛋白质表达与阴性对照组相比,P均>0.05.结论 rno_circRNA_016002在ISO诱导的大鼠肥厚的心肌组织和肥大心肌细胞中表达均上调,并且促进了心肌肥厚.

目的 探索木兰花碱对慢性不可预见性温和应激所致抑郁小鼠行为学的影响机制.方法 将ICR小鼠随机分为正常对照组(control组)、抑郁模型组(PG组)、木兰花碱高剂量组(MH组)和木兰花碱低剂量组(ML组).采用慢性不可预见性温和刺激方法建立抑郁小鼠模型,检测各组小鼠行为学的变化,并用实时定量PCR、Western blot检测小鼠脑部赖氨酸特异性组蛋白去甲基化酶1(LSD1)mRNA及蛋白表达水平的变化.免疫组化染色法检测小鼠脑部LSD1阳性细胞数量.结果 木兰花碱在行为学上改善了小鼠的抑郁状况,与PG组相比,MH组和ML组悬尾不动时间、强迫游泳不动时间明显缩短(P<0.05).实时定量PCR及Western blot结果显示,与control组相比,PG组LSD1 mRNA表达差异无统计学意义,蛋白表达明显降低(P<0.05),ML组LSD1 mRNA和蛋白表达明显升高(P<0.05);与PG组相比,ML组LSD1 mRNA和蛋白表达明显升高(P<0.05).免疫组化结果显示,与control组相比,PG组小鼠脑部LSD1阳性细胞数量减少,而ML组较PG组增加.结论 在木兰花碱治疗抑郁小鼠的过程中,LSD1可能起到了重要的调节作用.

Objective To construct the Hut78 cell line with EZH2 gene knocked into by CRISPR/Cas9 system. Methods The EZH2 expression vector pMD-18T-EZH2 with homologous arm and the sgRNA expression vector pSpCas9 (BB)-2A-Puro-sgRNA, which could cut the double stranded genomic DNA, were constructed, and the two vectors were co-transfected into Hut78 cells. Then the expression of EZH2 mRNA was detected by qPCR, and the expressions of EZH2 and H3K27me3 proteins were detected by Western blot assay. Results The pMD-18T-EZH2 and pSpCas9(BB)-2A-Puro-sgRNA recombinant vectors were confirmed by DNA sequencing. When Hut78 cells were transfected with the two recombinant plasmid, qPCR results showed that the expression of EZH2 mRNA was significantly increased, and Western blot analysis showed that the expressions of EZH2 and H3K27me3 proteins were significantly increased. Conclusion EZH2 gene is successfully knocked into Hut78 cells by CRISPR/Cas9 system.

Objective To constructe the rat-specific EZH2 overexpression plasmid and the EZH2 catalytic subunit SET domain deletion plasmid,as well as assess their levels of expression in 293T cells.Methods The RNA extracted from rat cardiac tissue was reverse-transcribed into cDNA,the cDNA of catalytic subunit SET domain deleted EZH2 was amplified by overlap PCR,then the PCR amplification was achieved using the EZH2 gene as template.Products through PCR amplification and vector were cut with double enzyme,and then ligated the target fragments,purified by gel extraction,using T4 ligase.The ligated products were transferred into competent cells.After plate coating,monoclonal picking,shaking cultivation and sequencing procedures,the plasmids were extracted and transfected into 293T cells using liposome-mediated method.Results Western Blot and RT-PCR assays showed recombinant plasmids DNA can successfully overexpress EZH2 gene in 293T cells.Conclusions Two plasmids were successfully constructed.This study laid the foundation for the further study on the relationship between EZH2 and myocardial hypertrophy,and the function of EZH2 catalytic subunit.