C-met及相关基因在m大鼠胰腺发育功能完善中的表达

目的：研究原癌基因c—met及其相关基因在大鼠胰腺发育及细胞功能完善过程中的表达。方法：采用高密度寡核苷酸芯片（Affymetrix芯片）对孕12．5（E12．5）、E15．5和E18．5、新生、成年胰腺进行基因转录水平分析,并用RT—PCR验证基因在大鼠胰腺不同发育时期的表达。结果：c—met基因在E15．5、E18．5较成年特异高表达。芯片中c—met转录调控基因和信号传导通路相关基因的表达趋势与c—met高度相似。RT—PCR（所用引物设计区域与芯片相同）验证,c—met表达趋势与芯片结果相符;与芯片c—met探针所用引物不同RT—PCR,结果却在各发育阶段呈现与芯片不同的表达趋势。结论：提示c—met可能在胰腺发育细胞功能完善的关键阶段起调控作用,参与胚胎胰腺发育中晚期细胞功能完善的信号传导过程。并且c—met在胰腺发育中发挥作用有可能存在不同转录本。     

Energy intake,oxidative stress and antioxidant in mice during lactation

Reproduction is the highest energy demand period for small mammals, during which both energy intake and expenditure are increased to cope with elevated energy requirements of offspring growth and somatic protection. Oxidative stress life history theory proposed that reactive oxygen species(ROS) were produced in direct proportion to metabolic rate, resulting in oxidative stress and damage to macromolecules. In the present study, several markers of oxidative stress and antioxidants activities were examined in brain, liver, kidneys, skeletal muscle and small intestine in non-lactating(Non-Lac) and lactating(Lac) KM mice. Uncoupling protein(ucps) gene expression was examined in brain, liver and muscle. During peak lactation, gross energy intake was 254% higher in Lac mice than in Non-Lac mice. Levels of H2O2 of Lac mice were 17.7% higher in brain(P<0.05), but 21.1%(P<0.01) and 14.5%(P<0.05) lower in liver and small intestine than that of Non-Lac mice. Malonadialdehyde(MDA) levels of Lac mice were significantly higher in brain, but lower in liver, kidneys, muscle and small intestine than that of Non-Lac mice. Activity of glutathione peroxidase(GSH-PX) was significantly decreased in brain and liver in the Lac group compared with that in the Non-Lac group. Total antioxidant capacity(TAOC) activity of Lac mice was significantly higher in muscle, but lower in kidneys than Non-Lac mice. Ucp4 and ucp5 gene expression of brain was 394% and 577% higher in Lac mice than in Non-Lac mice. These findings suggest that KM mice show tissuedependent changes in both oxidative stress and antioxidants. Activities of antioxidants may be regulated physiologically in response to the elevated ROS production in several tissues during peak lactation. Regulations of brain ucp4 and ucp5 gene expression may be involved in the prevention of oxidative damage to the tissue.     

Absence of association between N-acetyltransferase 2 acetylator status and colorectal cancer susceptibility: based on evidence from 40 studies

Background and Objectives

N-Acetyltransferase (NAT) 2 is an important enzyme involved in the metabolism of different xenobiotics, including potential carcinogens, whose phenotypes were reported to be related to individual susceptibility to colorectal cancer (CRC). However, the results remain conflicting. To assess the relationship between NAT2 phenotypes and CRC risk, we performed this meta-analysis.

Methods

A comprehensive literature search was conducted to identify all case-control or cohort studies of NAT2 acetylator status on the susceptibility of CRC by searching of PubMed and EMBASE, up to May 20, 2011. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association.

Results

A total of over 40,000 subjects from 40 published literatures were identified by searching the databases. No significantly elevated CRC risk in individuals with NAT2 slow acetylators compared with fast acetylators was found when all studies pooled (OR = 0.95, 95% CI: 0.87–1.04, I² = 52.6%). While three studies contributed to the source of heterogeneity were removed, there was still null result observed (OR = 0.96, 95% CI: 0.90–1.03, P = 0.17 for heterogeneity, I² = 17.8%). In addition, we failed to detect any associations in the stratified analyses by race, sex, source of controls, smoking status, genotyping methods or tumor localization. No publication bias was observed in this study.

Conclusions

This meta-analysis suggests that the NAT2 phenotypes may not be associated with colorectal cancer development.     

Polymorphisms of the DNA Methyltransferase 1 Associated with Reduced Risks of Helicobacter pylori Infection and Increased Risks of Gastric Atrophy

Introduction

DNA methyltransferase-1(DNMT1) is an important enzyme in determining genomic methylation patterns in mammalian cells. We investigated the associations between SNPs in the DNMT1 gene and risks of developing H. pylori seropositivity, gastric atrophy and gastric cancer in the Chinese population.

Methods

The study consisted of 447 patients with gastric cancer; 111 patients with gastric atrophy; and 961 healthy controls. Five SNPs, rs10420321, rs16999593, rs8101866, rs8111085 and rs2288349 of the DNMT1 gene were genotyped. Anti-H.pylori IgG was detected by ELISA. Gastric atrophy was screened by the level of serum pepsinogen Ιand II and then confirmed by endoscopy and histopatholgical examinations.

Results

The age- and sex-adjusted OR of H. pylori seropositivity was 0.67 (95%CI: 0.51–0.87) for rs8111085 TC/CC genotypes, significantly lower than the TT genotype in healthy controls. The adjusted OR of H.pylori seropositivity was 0.68 (95%CI: 0.52–0.89) for rs10420321 AG/GG genotypes. In addition, patients carrying rs2228349 AA genotype have a significantly increased risk for H.pylori seropositivity (OR = 1.67; 95%CI: 1.02–2.75). Further haplotype analyses also showed that the ATTTG and ATCTA are significantly associated with increased risks in H.pylori infection compared to the GTCCG haplotype (OR = 1.38, 95%CI: 1.08–1.77; OR = 1.40, 95% CI: 1.09–1.80). The adjusted ORs of gastric atrophy were 1.66 (95%CI: 1.06–2.61) for rs10420321 GG genotype, and 1.67 (95%CI 1.06–2.63, P = 0.03) for rs8111085 CC genotype, but no association was found between SNPs in the DNMT1 gene and risk of developing gastric cancer.

Conclusions

Individuals with rs10420321 GG and rs8111085 CC genotype of the DNMT1 gene were associated with reduced risks for H.pylori infection. On the other hand, higher risks of gastric atrophy were found in the carriers with these two genotypes compared to other genotypes. Our results suggested that SNPs of DNMT1 could be used as genotypic markers for predicting genetic susceptibilities to H.pylori infection and risks in gastric atrophy.     

Identification of a novel MTOR activator and discovery of a competing endogenous RNA regulating autophagy in vascular endothelial cells

MTOR, a central regulator of autophagy, is involved in cancer and cardiovascular and neurological diseases. Modulating the MTOR signaling balance could be of great significance for numerous diseases. No chemical activators of MTOR have been found, and the urgent challenge is to find novel MTOR downstream components. In previous studies, we found a chemical small molecule, 3-benzyl-5-((2-nitrophenoxy) methyl)–dihydrofuran-2(3H)-one (3BDO), that inhibited autophagy in human umbilical vein endothelial cells (HUVECs) and neuronal cells. Here, we found that 3BDO activated MTOR by targeting FKBP1A (FK506-binding protein 1A, 12 kDa). We next used 3BDO to detect novel factors downstream of the MTOR signaling pathway. Activation of MTOR by 3BDO increased the phosphorylation of TIA1 (TIA1 cytotoxic granule-associated RNA binding protein/T-cell-restricted intracellular antigen-1). Finally, we used gene microarray, RNA interference, RNA-ChIP assay, bioinformatics, luciferase reporter assay, and other assays and found that 3BDO greatly decreased the level of a long noncoding RNA (lncRNA) derived from the 3′ untranslated region (3′UTR) of TGFB2, known as FLJ11812. TIA1 was responsible for processing FLJ11812. Further experiments results showed that FLJ11812 could bind with MIR4459 targeting ATG13 (autophagy-related 13), and ATG13 protein level was decreased along with 3BDO-decreased FLJ11812 level. Here, we provide a new activator of MTOR, and our findings highlight the role of the lncRNA in autophagy.     

莲虾共作池塘夏季浮游植物群落及其与环境因子关系

为研究莲虾共作生态系统夏季浮游植物的群落结构特征,于2018年6月至8月对洪湖莲虾共作池塘的浮游植物和水质进行了定量调查监测,并探讨了浮游植物群落结构变化与环境因子之间的关系。结果显示,共鉴定有浮游植物7门71种属,其中绿藻门种类最多,蓝藻门和硅藻门种类次之,三者共占浮游植物总种类数的83.1%。浮游植物优势种有8种,以蓝藻门和绿藻门为主。莲虾共作池塘夏季浮游植物密度和生物量分别变化在2.50×10⁶~6.20×10⁷ cells/L和0.93~24.36 mg/L之间,浮游植物密度总体表现为逐渐升高的趋势,而浮游植物生物量为先升高后降低的趋势,且浮游植物各门的密度、生物量月份间差异不显著(P>0.05)。浮游植物Shannon-Wiener指数和Pielou均匀度指数均以7月最高出现峰值,不具有明显的月份差异(P>0.05);夏季各月的浮游植物多样性指数均较好,表明莲虾共作池塘浮游植物群落结构处于较稳定的状态。冗余分析（RDA）显示养殖期间的浮游植物物种密度受水温（WT）、总氮（TN）、氨氮（NH₄ ⁺—N）、高锰酸钾指数（COD_Mn）等多种环境因子的影响,而影响莲虾共作池塘各月浮游植物分布的关键环境因子是WT、NH₄ ⁺—N、TN。     

Generation of genetically modified mice by oocyte injection of androgenetic haploid embryonic stem cells

Haploid cells are amenable for genetic analysis. Recent success in the derivation of mouse haploid embryonic stem cells (haESCs) via parthenogenesis has enabled genetic screening in mammalian cells. However, successful generation of live animals from these haESCs, which is needed to extend the genetic analysis to the organism level, has not been achieved. Here, we report the derivation of haESCs from androgenetic blastocysts. These cells, designated as AG-haESCs, partially maintain paternal imprints, express classical ESC pluripotency markers, and contribute to various tissues, including the germline, upon injection into diploid blastocysts. Strikingly, live mice can be obtained upon injection of AG-haESCs into MII oocytes, and these mice bear haESC-carried genetic traits and develop into fertile adults. Furthermore, gene targeting via homologous recombination is feasible in the AG-haESCs. Our results demonstrate that AG-haESCs can be used as a genetically tractable fertilization agent for the production of live animals via injection into oocytes.     

热量限制通过HNF3γ下调NOX4表达来抑制内皮细胞的衰老

为了观察热量限制对主动脉内皮细胞中HNF3γ及NOX4基因表达的影响, 揭示HNF3γ-NOX4-活性氧通路介导热量限制抗内皮细胞衰老的分子机制, 文章将主动脉内皮细胞分为5组：对照组、高热量组、低热量组、siRNA+低热量组、siRNA+高热量组。应用逆转录实时定量PCR(Real-time quantitative PCR, RT-qPCR)、Western blotting分析各组HNF3γ、NOX4 mRNA及蛋白水平变化, 并检测各组细胞内活性氧产量及细胞衰老程度变化。采用染色质免疫共沉淀分析HNF3γ蛋白与NOX4基因启动子区域结合情况, 萤光素酶报告基因检测HNF3γ蛋白结合后对NOX4基因启动子活性的影响。结果显示：与对照组比较, 低热量组HNF3γ mRNA和总HNF3γ蛋白表达水平、磷酸化/总HNF3γ比值显著升高(P<0.05), NOX4 mRNA和蛋白表达水平、细胞内活性氧产量及细胞衰老程度显著降低(P<0.05); 高热量组HNF3γ mRNA和总HNF3γ蛋白表达水平、磷酸化/总HNF3γ比值显著降低(P<0.05), NOX4 mRNA和蛋白表达水平、细胞内活性氧产量及细胞衰老程度显著升高(P<0.05); siRNA+低热量组及siRNA+高热量组中NOX4 mRNA和蛋白表达水平、细胞内活性氧水平及细胞衰老程度显著升高(P< 0.05)。染色质免疫共沉淀证实HNF3γ蛋白可与NOX4基因启动区域4个结合位点(-6 bp、-76 bp、-249 bp、-954 bp)结合。萤光素酶报告基因检测显示HNF3γ蛋白与NOX4启动子区域1个位点(-6 bp)、2个位点(-6、-76 bp)、3个位点(-6、-76、-249 bp)、4个位点(-6、-76、-249、-954 bp)结合, 可使NOX4启动子活性分别降低至对照组的80.15±4.64%、40.02.±2.15%、16.46±2.24%、12.13±1.46%, P<0.05。上述结果提示热量限制可上调HNF3γ基因表达, 增强HNF3γ蛋白活性, 促进HNF3γ蛋白同NOX4基因启动子区域结合, 抑制NOX4基因表达, 进而减少细胞内活性氧产生而延缓动脉内皮细胞衰老。