Deficient expression of genes involved in the endogenous defense system against transposons in cryptorchid boys with impaired mini-puberty

Mini-puberty is the period between 30 and 80 days after birth when testosterone and gonadotropin surges occur in male infants to induce the transformation of gonocytes into adult/dark spermatogonia. Cryptorchid boys with impaired mini-puberty develop infertility despite timely and successful surgical treatment. The decreased germ cell count found in this group of boys could be the result of uncontrolled transposon activity inducing genomic instability and germ cell death. A genome-wide analysis of 18 cryptorchid and 4 control testes was performed with Affymetrix chips. We found that 5 of 8 genes that are important for transposon silencing were not expressed in the high azoospermia risk group of cryptorchid boys but were expressed in the low azoospermia risk and control groups. Two genes, CBX3 and DNMT1, were equally expressed in all 3 groups. Impaired expression of the DDX4, MAEL,MOV10L1, PIWIL2, PIWIL4, and TDRD9 genes in the group of cryptorchid boys at high risk of infertility indicates that gene instability induced by impaired expression of transposon silencing genes contribute to the development of azoospermia. Intact mini-puberty appears to be essential for the development of the endogenous defense system mediated by transposon silencing.     

Expression levels of genes likely involved in glucose-sensing in the obese Zucker rat brain

It has been suggested that certain cells in the brain, like pancreatic beta-cells, use glucose transporter-2 (GLUT-2), glucokinase and glucagon-like peptide-1 receptor (GLP-1R) to sense glucose in the service of multiple aspects of energy balance. The obese Zucker rat displays numerous disturbances in energy homeostasis and may provide a model of dysfunctional expression of genes related to nutrient control systems. Using real-time RT-PCR we measured gene expression for three of the pancreatic glucose-sensing markers and neuropeptide Y (NPY) in the medial, lateral hypothalamus and hindbrain of lean and obese Zucker rats of both genders. Additionally, we measured circulating levels of glucose, leptin, insulin, corticosterone and glucagon. The results indicate that GLUT-2 mRNA expression is decreased, whereas glucokinase is increased in the hindbrain of obese rats. NPY mRNA level is significantly higher, whereas GLP-1R is significantly lower in the medial hypothalamus in obese individuals. Gender-related differences were found in the hindbrain and medial hypothalamus for GLUT-2 and in the lateral hypothalamus for GLP-1R and they may be related to the fact that the female Zucker rats do not develop diabetes as readily as males. Furthermore, the hindbrain may be an important site for glucose-sensing where major phenotypic changes occur for glucose-sensing genes expression.     

Postprandial insulin response and mitochondrial oxidation in obese men nutritionally treated to lose weight

Obesity, hyperglycemia, and insulin resistance have been associated to an oxidative mitochondrial dysfunction. The aim of this research was to evaluate the relation between carbohydrate metabolism and mitochondrial oxidation, as affected by the weight status and the weight loss induced by a calorie-restricted diet. Lean control men (BMI<25 kg/m2, n = 6) and obese men (BMI>30 kg/m2, n = 14), who were characterized as insulin resistant (n = 6) or insulin sensitive (n = 8) based on HOMA index values, participated in the trial. Plasma insulin levels and mitochondrial oxidation estimated by the 2-keto(1-13C)isocaproate breath test, were measured after ingestion of a test meal during 3 h. Obese subjects repeated the breath test protocol after a 10-week caloric restriction diet to lose weight. Postprandial insulin secretion tended to be marginally higher (P = 0.059) in both obese groups than in controls, while the rate of postprandial mitochondrial oxidation was markedly decreased (P = 0.019) in the obese subjects as compared with lean individuals. The nutritionally induced weight loss produced a rise in the postprandial oxidative process in volunteers initially considered as insulin resistant (P = 0.036), while no statistical differences in the insulin-sensitive obese (P = 0.241) were found. Interestingly, the percentage of oxidized tracer was inversely related to postprandial insulin secretion (r = -0.56; P = 0.001). In conclusion, these results support the hypothetized relation between carbohydrate metabolism and mitochondrial oxidation at a postprandial state in obese subjects, raising interest about mitochondria stimulation as a target in the therapy of obesity.     

Short-term effects of a hypocaloric diet on nitrogen excretion in morbid obese women

OBJECTIVE: To determine whether the daily pattern of urine excretion of N wastes is affected by obesity and very low-calorie diets (VLCD). DESIGN: The plasma amino acid, urea and other energy parameters, as well as the urinary excretion of total nitrogen, urea and creatinine were studied in obese and normal-weight women. The obese women's data were obtained under hospital basal controlled conditions (8.1 MJ/day) and after 3 days of VLCD diet (1.9 MJ/day) controls were studied only once (5.8 MJ/day). The hourly excretion patterns of total N, urea and creatinine were determined from the composition of each bladder voiding. SUBJECTS: Twenty morbidly obese and 10 age-matched normal-weight control women. RESULTS: Plasma amino acid levels were higher in obese women, which showed a limited ability to metabolize amino acid hydrocarbon skeletons. Neither differences in the patterns between groups nor total 24 h values for urine volume were found. Total N and urea excretion diminished under VLCD diet. Hourly creatinine excretion showed a flat pattern and was higher in obese women than in the controls, VLCD diet diminished the amount of creatinine excreted in 24 h. CONCLUSIONS: The early change in energy availability that the creatinine excretion figures reflect may result from the energy conservation mechanisms induced in response to energy restriction. The early onset of this effect (3 days, and the extent of decrease (approximately 19%) also suggest that the impact of VLCD on the muscle energy budget of the obese is more marked than usually assumed.     

铬对膳食诱导的肥胖大鼠血清中瘦素的影响

目的 研究铬对大鼠肥胖基因表达的影响及其与胰岛素、生长激素和睾酮的关系。方法 先以高脂饲料造成大肥胖模型（每组22只）,再以灌胃方式给实验组补充铬（以葡萄糖酸铬的形式给予,相当于Cr^3 3mg/kg),对照组给予去离子水,并于灌胃后1d、1周、2周和3周分别制备血清测定瘦素、胰岛素、生长激素和睾酮等指标。结果 实验组与对照组相比,其瘦素、胰岛素水平显降低,而生长激素和睾酮水平显升高。结论 葡萄糖酸铬可抑制肥胖基因的表达和胰岛素的分泌,促进生长激素和睾酮的分泌。     

miRNAs and genes expression in MARC-145 cell in response to PRRSV infection

The regulation of viral replication is under control of miRNAs and their target genes. Several articles report the cross-talk between host and virus. The drastic effects of Porcine reproductive and respiratory syndrome virus (PRRSV) pressed us to investigate the expression profiling of miRNAs and immunity related genes during PRRSV infection. This was performed by qPCR in MARC145 cells during PRRSV infection. It was observed that miRNAs and genes show different expression patterns at different time points during PRRSV infection. The early infected stage was accompanied with increased expression of some miRNAs including miR-204, miR-21, miR-181a, miR-29 while a decrease was observed for the same in late infection stage. The opposite condition also existed in parallel. An interesting observation was seen when miR-145 was strongly induced by PRRSV infection, whereas miR-127 expression was significantly reduced in all infection points. Taken together, our studies have revealed that the expressions of miRNAs and immune-related genes were regulated in PRRSV infected MARC-145 cells and had important roles in the immune response, providing a basis for further investigations.     

Effects of expression level of DNA repair-related genes involved in the NHEJ pathway on radiation-induced cognitive impairment

Cranial radiation therapy can induce cognitive decline. Impairments of hippocampal neurogenesis are thought to be a paramountly important mechanism underlying radiation-induced cognitive dysfunction. In the mature nervous system, DNA double-strand breaks (DSBs) are mainly repaired by non-homologous end-joining (NHEJ) pathways. It has been demonstrated that NHEJ deficiencies are associated with impaired neurogenesis. In our study, rats were randomly divided into five groups to be irradiated by single doses of 0 (control), 0 (anesthesia control), 2, 10, and 20 Gy, respectively. The cognitive function of the irradiated rats was measured by open field, Morris water maze and passive avoidance tests. Real-time PCR was also used to detect the expression level of DNA DSB repair-related genes involved in the NHEJ pathway, such as XRCC4, XRCC5and XRCC6, in the hippocampus. The influence of different radiation doses on cognitive function in rats was investigated. From the results of the behavior tests, we found that rats receiving 20 Gy irradiation revealed poorer learning and memory, while no significant loss of learning and memory existed in rats receiving irradiation from 0–10 Gy. The real-time PCR and Western blot results showed no significant difference in the expression level of DNA repair-related genes between the 10 and 20 Gy groups, which may help to explain the behavioral results, i.e. DNA damage caused by 0–10 Gy exposure was appropriately repaired, however, damage induced by 20 Gy exceeded the body''s maximum DSB repair ability. Ionizing radiation-induced cognitive impairments depend on the radiation dose, and more directly on the body''s own ability to repair DNA DSBs via the NHEJ pathway.     

检测黄曲霉毒素生物合成相关基因芯片的研制

目的 建立比较成熟的可用于分析黄曲霉毒素生物合成相关基因的芯片技术.方法 采用反转录PCR和芯片检测对比的方法.实验所用探针来源于寄生曲霉,待测样品选择黄曲霉菌株.结果 芯片点阵后依次通过温浴2 h,650 mJ/cm<'2>紫外交联30 S,80℃烘烤2 h,预杂交45 min,清洗,干燥等步骤,最后与待测样品在42℃杂交16 h,获得了低背景高质量的芯片.芯片扫描显示荧光信号稳定,与反转录PCR扩增结果一致,并且无背景干扰.结论 探针设计合理,实验方法可靠.初步建立了用芯片检测与黄曲霉毒素生物合成相关基因的技术平台.     

Epigallocatechin gallate changes mRNA expression level of genes involved in cholesterol metabolism in hepatocytes

Catechins, compounds derived from green tea, have been shown to improve cholesterol metabolism in animal studies, but the molecular mechanisms underlying this function have not been fully understood. We performed DNA microarray analysis in order to clarify the effects of epigallocatechin gallate (EGCG), the dominant catechin in green tea, on cholesterol metabolism in HepG2 hepatocytes. This revealed that the expression levels of several genes related to cholesterol metabolism, including the LDL receptor, were changed by EGCG treatment. Using a real-time PCR technique, we confirmed that EGCG treatment up-regulated mRNA expression level of the LDL receptor. Moreover, EGCG decreased extracellular apoB levels. These findings indicated that EGCG improves cholesterol metabolism through the up-regulation of LDL receptor and also reduces extracellular apoB levels.     

基因组学技术初步分析甲基汞神经毒性功能基因

目的探讨甲基汞神经毒性差异表达基因功能。方法利用基因芯片筛选大鼠暴露体重剂量为0·5mg/Kg的氯化甲基汞后脑中的差异表达基因,并利用基因组学技术分析其功能。结果基因表达谱中差异表达基因共有303条,其中上调基因为170条,下调基因为133条。发生显著性改变的功能基因主要涉及到①免疫应答及解毒作用;②遗传信息传递与表达;③细胞信号传导;④神经传导;⑤细胞增殖与分化;⑥细胞凋亡;⑦其它未知功能等7组。在暴露组样本中,脑中有关细胞信号传导和神经传导功能基因发生了特别显著的差异表达。结论甲基汞通过对信号传导过程的影响,发挥其神经毒性的作用。     

Green tea extract suppresses adiposity and affects the expression of lipid metabolism genes in dietinduced obese zebrafish

ABSTRACT: BACKGROUND: Visceral fat accumulation is one of the most important predictors of mortality in obese populations. Administration of green tea extract (GTE) can reduce body fat and reduce the risk of obesity-related diseases in mammals. In this study, we investigated the effects and mechanisms of GTE on adiposity in diet-induced obese (DIO) zebrafish. METHODS: Zebrafish at 3.5 to 4.5 months post-fertilization were allocated to four groups: non-DIO, DIO, DIO + 0.0025%GTE, and DIO + 0.0050%GTE. The non-DIO group was fed freshly hatched Artemia once daily (5 mg cysts/fish daily) for 40 days. Zebrafish in the three DIO groups were fed freshly hatched Artemia three times daily (60 mg cysts/fish daily). Zebrafish in the DIO + 0.0025%GTE and DIO + 0.0050%GTE groups were exposed to GTE after the start of feeding three times daily for 40 days. RESULTS: Three-dimensional microcomputed tomography analysis showed that GTE exposure significantly decreased the volume of visceral but not subcutaneous fat tissue in DIO zebrafish. GTE exposure increased hepatic expression of the lipid catabolism genes ACOX1 (acyl-coenzyme A oxidase 1, palmitoyl), ACADM (acyl-coenzyme A dehydrogenase, c-4 to c- 12 straight chain), and PPARA (peroxisome proliferator-activated receptor alpha). GTE exposure also significantly decreased the visceral fat expression of SOCS3 (suppressor of cytokine signaling 3b) which inhibits leptin signaling. CONCLUSIONS: The present results are consistent with those seen in mammals treated with GTE, supporting the validity of studying the effects of GTE in DIO zebrafish. Our results suggest that GTE exerts beneficial effects on adiposity, possibly by altering the expression of lipid catabolism genes and SOCS3.     

甲基叔丁基醚对原癌基因和功能基因表达的影响

甲基叔丁基醚（ＭＴＢＥ）是一种新型的汽油添加剂,被用来提高汽油燃烧效率,减少汽车尾气中有害物质的排放。ＭＴＢＥ具有一定的动物致癌性,但其机制目前并不清楚。本研究采用免疫组织化学方法,检测了ＭＴＢＥ对体外培养的ＮＩＨ３Ｔ３细胞中ｃ－ｍｙｃ和ｐ２１蛋白表达的影响;采用点杂交方法,从ＲＮＡ水平检测了ＭＴＢＥ亚慢性染毒大鼠肝组织中原癌基因ｃ－ｍｙｃ基因和功能基因ＧＳＴ－Ｐ基因的表达情况。免疫组化结果显示,ＭＴＢＥ可诱导ｃ－ｍｙｃ基因的高表达,对ｐ２１蛋白的表达未见明显影响。点杂交结果显示,ＭＴＢＥ可明显诱导大鼠肝组织中ｃ－ｍｙｃ基因的高表达,而对ＧＳＴ－Ｐ基因的表达未见明显影响。上述结果提示,ＭＴＢＥ可诱导细胞中ｃ－ｍｙｃ基因表达活性增高,可能是其动物致癌性的机制之一。     

肥胖儿童食欲调节因子基因启动子区DNA甲基化探讨

目的 探讨肥胖儿童瘦素、瘦素受体及促阿片-黑素细胞皮质素原(proopiomelanocortin,POMC)基因启动子区CpG位点的甲基化改变。方法 选取北京酒仙桥地区45例4~6岁单纯性肥胖儿童及按性别、年龄1∶1 配对的45例正常儿童为研究对象。利用外周血提取基因组DNA,然后应用亚硫酸盐修饰直接测序法(BSP)和半巢式PCR检测儿童瘦素基因启动子区(324 bp,-228到+96)25个CpG位点、瘦素受体基因启动子区(271 bp,-411到-141)20个CpG位点及POMC基因启动子区(275 bp,-341到-67)18个CpG位点的甲基化状态;同时采用酶联免疫分析测定血浆瘦素含量。结果 单纯性肥胖儿童血浆瘦素含量(21.24±4.02) μg/L显著高于正常儿童(2.95±0.53) μg/L。肥胖儿童瘦素基因启动子区CpG位点的平均甲基化程度(0.43±0.13)显著低于正常儿童(0.52±0.15);对该启动子区单个CpG位点比较发现,9个位点的甲基化程度在肥胖组低于对照组。瘦素受体基因启动子区各CpG位点在两组儿童中均呈现完全去甲基化状态。POMC基因启动子区各CpG位点甲基化程度在肥胖与正常儿童之间均未见显著差异。结论 肥胖儿童瘦素基因启动子区CpG位点存在甲基化改变,可能与瘦素表达增加、瘦素抵抗发生有关。     

Lipoic acid increases the expression of genes involved in bone formation in mice fed a high-fat diet

Antioxidant lipoic acid (LA) has been reported to have a potential prophylactic effect on bone loss induced by high-fat diet (HFD). The aim of this work was to examine the hypothesis that LA decreases bone resorption-related gene expression and increases bone formation-related gene expression in HFD-fed mice, preventing a shift in the bone metabolism balance toward resorption. Male C57BL/6 mice were fed a normal diet, HFD, or HFD plus 0.1% LA for 12 weeks. The bone metabolism-related genes differentially expressed between mice fed HFD and those fed HFD supplemented with LA were identified through complementary DNA microarray. The supplemental LA significantly increased bone mineral density and bone antioxidant capacity in mice fed HFD (P < .05). Compared with the HFD-fed mice, LA induced the decreased expression of genes associated with bone resorption, such as Mmp9 (1.9-fold) and Ctsk (2.3-fold), and increased those genes associated with bone formation, such as Col1a1 (1.3-fold) and Alp1 (1.5-fold). Furthermore, LA upregulated many genes involved in the Igf signaling pathway, such as Igf-1 (increased 1.7-fold), and downregulated genes involved in the p53 apoptotic pathway, such as p53 (decreased 2.3-fold), thus attenuating the HFD-induced inhibition of bone formation. Lipoic acid induced upregulation of Il12a (2.1-fold) and downregulation of Tgfbr1 (4.3-fold) and Il17a (11.3-fold), which may reduce bone resorption. In summary, LA supplementation during HFD could affect bone density, altering gene expression.