Overexpression of Bcl-2 in transgenic mice decreases apoptosis and improves survival in sepsis

In sepsis there is extensive apoptosis of lymphocytes, which may be beneficial by down-regulating the accompanying inflammation. Alternatively, apoptosis may be detrimental by impairing host defense. We studied whether Bcl-2, a potent antiapoptotic protein, could prevent lymphocyte apoptosis in a clinically relevant model of sepsis. Transgenic mice in which Bcl-2 was overexpressed in T cells had complete protection against sepsis-induced T lymphocyte apoptosis in thymus and spleen. Surprisingly, there was also a decrease in splenic B cell apoptosis in septic Bcl-2 overexpressors compared with septic HeJ and HeOuJ mice. There were marked increases in TNF-alpha, IL-1beta, and IL-10 in thymic tissue in sepsis in the three species of mice, and the increase in TNF-alpha and IL-10 in HeOuJ mice was greater than that in Bcl-2 mice. Mitotracker, a mitochondrial membrane potential indicator, demonstrated a sepsis-induced loss of membrane potential in T cells in HeJ and HeOuJ mice but not in Bcl-2 mice. Importantly, Bcl-2 overexpressors also had improved survival in sepsis. To investigate the potential impact of loss of lymphocytes on survival in sepsis, Rag-1-/- mice, which are totally deficient in mature T and B cells, were also studied. Rag-1-/- mice had decreased survival compared with immunologically normal mice with sepsis. We conclude that overexpression of Bcl-2 provides protection against cell death in sepsis. Lymphocyte death may be detrimental in sepsis by compromising host defense.     

LPS诱导脓毒症小鼠脾组织microRNA表达的筛选研究

目的采用Small RNA测序技术检测脓毒症小鼠24 h脾组织microRNA(miRNA)的表达变化,并从非编码基因层面分析脓毒症脾功能损伤的可能机制。方法将30只SPF级健康BALB/C小鼠随机分为对照组和脓毒症组,每组15只。脓毒症组采用LPS 10 mg/kg腹腔注射进行建模,对照组仅予等量生理盐水腹腔注射。两组术毕均行肌肉注射平衡液5 ml/kg,并于术后24 h各组随机取5只小鼠的脾组织提取RNA,采用Small RNA测序技术进行miRNA检测,然后应用生物信息学软件分析脓毒症小鼠脾组织的miRNA表达差异及靶基因预测。结果小鼠建模后24 h,与对照组相比,脓毒症小鼠脾脏组织已知及未知miRNA表达上调数分别为39个、3个,下调数分别为16个、3个。其中已知miRNA表达上、下调倍数最大的前5个基因分别为Rno-miR-217-5p,rno-mir-216a-5p,rnomiR-216b-5p,rno-miR-375-3p,rno-mir-216b-3p。下调倍数前5的miRNA:Rno-miR-138-5p,rno-miR-451a-3p,rno-miR-138-1-3p,rno-miR-202-5p,rno-miR-592。结论LPS诱导脓毒症小鼠可出现miRNA表达量的改变,其上、下调倍数最显著的miRNA可能对预测LPS诱导的脓毒症脾功能损伤有一定指导意义。     

Differential profiles of genes expressed in neonatal brain of 129X1/SvJ and C57BL/6J mice: A database to aid in analyzing DNA microarrays using nonisogenic gene-targeted mice.

Strain-specific differences in gene expression have been observed among various inbred mouse strains. Two strains that are commonly used in gene-targeting research today are the 129 substrains, which are used to produce ES cell lines, and C57BL/6J, which is used for the extensive backcrosses required to produce isogenic knockout mice. When F2 nonisogenic littermates are assessed using DNA microarrays, one must determine whether the expression profiles obtained resulted either from specific alteration(s) induced by the targeted gene mutation or from gene expression differences related to the genetic background of the parent mouse strains. In the present study, we report the differential expression profile of genes expressed in neonatal brains and adult spleen and liver of 129X1/SvJ and C57BL/6J strains of mice. These comprehensive profiles were assessed using two types of Agilent Mouse Oligo Microarrays (development and standard) and were compiled into a publicly available database. Researchers can use this database to determine whether their microarray findings represent strain-specific differences in gene expression by comparing their data with those cataloged in our database. This database is useful for effectively analyzing DNA microarray data from nonisogenic littermates, and would help researchers avoid time-consuming backcrosses and confirmatory experiments requiring the use of many mice.     

糖尿病小鼠胚胎早期发育的差异表达基因

目的利用小鼠糖尿病模型,探讨母体糖尿病环境对早期胚胎基因表达的影响。方法ICR雌性小鼠腹腔注射150mg／kg剂量STZ诱发糖尿病,与正常雄鼠交配受孕,取14d胎龄的胚胎,提取胚胎的总RNA。将Cy3和Cy52种荧光分别标记到实验组和对照组的RNA上,制成RNA探针,并与包含24859个基因的表达谱芯片进行杂交及扫描,重复3次实验,采用Agilent扫描仪进行扫描软件读取数据。结果筛选出差异表达基因397个,其中有328个基因在实验组表达量比对照组大2倍,69个基因在实验组表达量比对照组小2倍。结论母体糖尿病环境能影响早期胎儿的基因表达,通过上调代谢相关基因和下调发育相关基因影响小鼠胚胎的早期发育。为深入探讨糖尿病胚胎病理和代谢疾病的分子机理提供了基本数据和研究的方向。     

Modification of gene expression by dietary antioxidants in radiation-induced apoptosis of mice splenocytes

The modification of radiation-induced apoptosis in splenocytes by a vitamin-containing dietary supplement was studied. For 45 days prior to irradiation at a lethal dose of 6 Gy, mice received a dietary supplement containing vitamins with antioxidant properties and microelements. The expression of TRPM-2 (a marker for programmed cell death), bcl-2 (the product of which has been shown to prevent apoptosis), superoxide dismutase, and catalase genes was studied at different time intervals after irradiation. Radiation-induced alterations in gene expression were different in the control and the antioxidant mixture-fed mice. The antioxidant mixture administration resulted in an inhibition of TRPM-2 expression both before and after irradiation. The bcl-2 mRNA content steadily increased after irradiation in splenocytes from antioxidant mixture-fed mice, while in the control group 2-h after irradiation only trace amount of bcl-2 mRNA was detected. In splenocytes from control mice, the expression of superoxide dismutase and catalase genes significantly decreased within 2-h after irradiation; whereas in mice receiving the antioxidant mixture, inhibition of catalase gene expression was not as prominent. The expression of superoxide dismutase gene was still high 24-h after irradiation. The antioxidant administration decreased the radiation-induced apoptosis and delayed internucleosomal fragmentation of DNA. Our data suggest that radiation-induced alteration of gene expression is, at least in part, determined by reactive oxygen species.     

Differential gene expression in pancreatic tissues of streptozocin-induced diabetic rats and genetically-diabetic mice in response to hypoglycemic dipeptide cyclo (His-Pro) treatment

Diabetic studies are mostly interested in gene expression in the pancreas, the site of insulin secretion that regulates blood glucose levels. However, a single gene approach has been ruled out for many years in discovering new genes or the molecular networks involved in the induction process of diabetes. To understand the molecular mechanisms by which cyclo (His-Pro) (CHP) affects amelioration of diabetes mellitus, we performed gene expression profiling in the pancreatic tissues of two diabetic animal models, streptozocin (STZ)-induced diabetic rats (T1DM) and genetically-diabetic (C57BL/6J ob/ob) mice (T2DM). To understand the healing process of these diabetic rodents, we examined the effects of CHP on various gene expression in pancreatic tissues of both animal models. Our microarray analysis revealed that a total of 1,175 genes were down-regulated and 629 genes were up-regulated in response to STZ treatment, and the altered expression levels of numerous genes were restored to normal state upon CHP treatment. In particular, 476 genes showed significantly altered gene expression upon CHP treatment. In a functional classification, 7,198 genes were counted as differentially expressed in pancreatic tissues of STZ- and CHP-treated rats compared with control, whereas 1,534 genes were restored to normal states by CHP treatment. Microarray data demonstrated for the first time that overexpression of the genes encoding IL-1 receptor, lipid metabolic enzymes (e.g. Mte1, Ptdss1, and Sult2a1), myo-inositol oxygenase, glucagon, and somatostatin as well as down-regulation of olfactory receptor 984 and mitochondrial ribosomal protein, which are highly linked to T1DM etiology. In genetically-diabetic mice, 4,384 genes were altered in gene expression by more than 2-fold compared to the control mice, when counted differentially expressed. In genetically-diabetic mice, 4,384 genes altered in expression by higher than 2-fold were counted as differentially expressed genes in pancreatic tissues of CHP-treated mice. On the other hand, 2,140 genes were up-regulated and 2,244 genes were down-regulated by CHP treatment. The results of the microarray analysis revealed that up-regulation of IL-2, IL12a, and leptin receptor and down-regulation of PIK3 played important physiological roles in the onset of T2DM. In conclusion, we hypothesize that CHP accelerates alterations of gene expression in ameliorating diabetes and antagonizes those that induces the disease.