Cell proliferation and neuroblast differentiation in the dentate gyrus of high-fat diet-fed mice are increased after rosiglitazone treatment

In this study, we determined how rosiglitazone (RSG) differentially affected hippocampal neurogenesis in mice fed a low-fat diet (LFD) or high-fat diet (HFD; 60% fat). LFD and HFD were given to the mice for 8 weeks. Four weeks after initiating the LFD and HFD feeding, vehicle or RSG was administered orally once a day to both groups of mice. We measured cell proliferation and neuroblast differentiation in the subgranular zone of the dentate gyrus using Ki67 and doublecortin (DCX), respectively, as markers. In addition, we monitored the effects of RSG on the levels of DCX and brain-derived neurotrophic factor (BDNF) in hippocampal homogenates. At 8 weeks after the LFD feeding, the numbers of Ki67- and DCX-positive cells as well as hippocampal levels of DCX and BDNF were significantly decreased in the RSG-treated group compared to the vehicle-treated animals. In contrast, the numbers of Ki67- and DCX-positive cells along with hippocampal levels of DCX and BDNF in the HFD fed mice were significantly increased in the RSG-treated mice compared to the vehicle-treated group. Our data demonstrate that RSG can modulate the levels of BDNF, which could play a pivotal role in cell proliferation and neuroblast differentiation in the hippocampal dentate gyrus.     

N-acetylserotonin increases cell proliferation and differentiating neuroblasts with tertiary dendrites through upregulation of brain-derived neurotrophic factor in the mouse dentate gyrus

In this study, we investigated the effects of N-acetylserotonin (NAS) on cell proliferation and neuroblast differentiation in the mouse dentate gyrus using anti-Ki67 and anti-doublecortin (DCX) antibodies. Ki67 is expressed in the nucleus or on the surface of chromosomes during all of the active phases of the cell cycle, and DCX is expressed in neuronal precursor cells as well as in immature neurons. At 17 weeks of age, 20 mg/kg of NAS or the same volume of vehicle was intraperitoneally administered once a day for 3 weeks. The animals were sacrificed 2 hr after the last vehicle or NAS treatment. NAS treatment significantly increased the number of Ki67-positive nuclei and DCX-immunoreactive neuroblasts with well-developed dendrites (tertiary dendrites) compared to the vehicle-treated group. However, the number of DCX-immunoreactive neuroblasts without tertiary dendrites was not changed. The administration of NAS also significantly increased the protein levels of brain-derived neurotrophic factor (BDNF) in the dentate gyrus. This result suggests that NAS significantly promotes cell proliferation and the number of differentiating neuroblasts with tertiary dendrites through an increase in BDNF levels in the mouse dentate gyrus.     

Adult neurogenesis in the mammalian dentate gyrus

Earlier observations in neuroscience suggested that no new neurons form in the mature central nervous system. Evidence now indicates that new neurons do form in the adult mammalian brain. Two regions of the mature mammalian brain generate new neurons: (a) the border of the lateral ventricles of the brain (subventricular zone) and (b) the subgranular zone (SGZ) of the dentate gyrus of the hippocampus. This review focuses only on new neuron formation in the dentate gyrus of the hippocampus. During normal prenatal and early postnatal development, neural stem cells (NSCs) give rise to differentiated neurons. NSCs persist in the dentate gyrus SGZ, undergoing cell division, with some daughter cells differentiating into functional neurons that participate in learning and memory and general cognition through integration into pre-existing neural networks. Axons, which emanate from neurons in the entorhinal cortex, synapse with dendrites of the granule cells (small neurons) of the dentate gyrus. Axons from granule cells synapse with pyramidal cells in the hippocampal CA3 region, which send axons to synapse with CA1 hippocampal pyramidal cells that send their axons out of the hippocampus proper. Adult neurogenesis includes proliferation, differentiation, migration, the death of some newly formed cells and final integration of surviving cells into neural networks. We summarise these processes in adult mammalian hippocampal neurogenesis and discuss the roles of major signalling molecules that influence neurogenesis, including neurotransmitters and some hormones. The recent controversy raised concerning whether or not adult neurogenesis occurs in humans also is discussed.     

Effects of plant-induced hypervitaminosis D on cutaneous structure, cell differentiation and cell proliferation in cattle

Solanum glaucophyllum (Sg) (synonym S. malacoxylon) is a plant toxic to cattle due to its high levels of 1,25-dihydroxyvitamin D3 as glycoside derivatives. Sg causes a disease characterized by wasting and calcification of soft tissues. The effects of vitamin D are not only important in calcium homeostasis, but also in immune regulation, cell growth and cell differentiation. Skin samples in Sg-intoxicated and control heifers were studied histologically. Cellular differentiation and proliferation were analysed by immunohistochemical expression of cytokeratins, involucrin and proliferating cell nuclear antigen (PCNA). The results were obtained by image processing and analysis and were statistically evaluated. Sg-intoxicated cattle showed atrophy of epidermis and severe involution of hair follicles and of sebaceous and sweat glands. As judged by PCNA expression, cellular proliferation was reduced, even though the reduction was not statistically significant. The analysed markers of differentiation, e.g. involucrin and cytokeratins 10 and 11, changed in relation to Sg-poisoning. The possible pathogenesis of the skin lesions is discussed.     

色氨酸分解代谢对T细胞分化增殖的影响

色氨酸是动物必需氨基酸之一。体内色氨酸在吲哚胺-2,3-双加氧酶(IDO)等相关酶的作用下进行分解代谢,发挥重要生理作用,包括抑制T细胞分化增殖和影响T细胞功能。本文就色氨酸分解代谢对T淋巴细胞的影响及可能机理作一综述。     

胰岛素对原代培养大鼠前体脂肪细胞增殖分化的影响

对分离自20日龄雄性SD大鼠附睾和肾周白色脂肪组织的前体脂肪细胞进行原代培养，并采用MTT比色法、油红O染色提取法分析了100～400nmol／L胰岛素对其增殖、分化的影响，同时利用半定量RT-PCR分析了该浓度胰岛素对分化标志基因——脂肪酸合酶（FAS）、乙酰CoA羧化酶α（ACC1）基因mRNA表达的影响。结果显示，胰岛素能有效地促进前体脂肪细胞的增殖和分化（P〈0．05），在400nmol／L以下具有剂量依赖性；胰岛素处理72h能显著提高脂肪细胞FAS和ACC1基因mRNA的表达水平（P〈0．05）。证实胰岛素对原代培养大鼠前体脂肪细胞增殖分化有明显促进作用。     

YAP对梅花鹿鹿茸间充质细胞增殖与分化的影响

以梅花鹿为研究对象,通过流式细胞术、荧光定量PCR等方法,探讨YAP(Yes-associated protein,即Yes相关蛋白)对鹿茸间充质细胞增殖与分化的影响.分离培养鹿茸间充质细胞,添加一定浓度的YAP抑制剂Verteporfin后,通过流式细胞术检测发现,细胞的增殖活性被显著抑制,G0/G1期细胞百分比增加...     

Effects of aluminum on the reduction of neural stem cells,proliferating cells,and differentiating neuroblasts in the dentate gyrus of D-galactose-treated mice via increasing oxidative stress

Aluminum (Al) accumulation increases with aging, and long-term exposure to Al is regarded as a risk factor for Alzheimer''s disease. In this study, we investigated the effects of Al and/or D-galactose on neural stem cells, proliferating cells, differentiating neuroblasts, and mature neurons in the hippocampal dentate gyrus. AlCl₃ (40 mg/kg/day) was intraperitoneally administered to C57BL/6J mice for 4 weeks. In addition, vehicle (physiological saline) or D-galactose (100 mg/kg) was subcutaneously injected to these mice immediately after AlCl₃ treatment. Neural stem cells, proliferating cells, differentiating neuroblasts, and mature neurons were detected using the relevant marker for each cell type, including nestin, Ki67, doublecortin, and NeuN, respectively, via immunohistochemistry. Subchronic (4 weeks) exposure to Al in mice reduced neural stem cells, proliferating cells, and differentiating neuroblasts without causing any changes to mature neurons. This Al-induced reduction effect was exacerbated in D-galactose-treated mice compared to vehicle-treated adult mice. Moreover, exposure to Al enhanced lipid peroxidation in the hippocampus and expression of antioxidants such as Cu, Zn- and Mn-superoxide dismutase in D-galactose-treated mice. These results suggest that Al accelerates the reduction of neural stem cells, proliferating cells, and differentiating neuroblasts in D-galactose-treated mice via oxidative stress, without inducing loss in mature neurons.     

不同海拔孵化对鸡胚肝细胞增殖的影响

研究发现,将适应平原环境的高产品种种蛋运送到西藏高原环境孵化常出现孵化率降低、死亡率增高、胚胎发育迟缓和畸形率增高等现象[1];且鸡胚各组织器官的生长发育也与平原孵化存在一定差别[1-2]。为了探讨高原对细胞增殖、分化时序影响的机理,本试验采用不同海拔(北京和西藏林芝)孵化的鸡胚研究两种孵化条件下鸡胚肝细胞增殖的日龄变化差异,以期为促进高原地区鸡的繁殖育种提供理论依据。1材料与方法1.1实验动物与孵化条件农大小型鸡D种蛋,由中国农业大学实验种鸡场提供。分2组。(1)高原孵化组:西藏大学牧医系养鸡场孵化室(西藏林芝,海拔2 …     

Changes in glial fibrillary acidic protein immunoreactivity in the dentate gyrus and hippocampus proper of adult and aged dogs

Astrocytes perform neuron-supportive tasks, repair and scarring process in the central nervous system. In this study, we observed glial fibrillary acidic protein (GFAP), a marker for astrocytes, immunoreactivity in the dentate gyrus and hippocampus proper (CA1-3 region) of adult (2-3 years of age) and aged (10-12 years of age) dogs. In the adult group, GFAP immunoreactive astrocytes were distributed in all layers of the dentate gyrus and CA1-3 region, except in the stratum pyramidale of the CA1-3 region. In the aged group, GFAP immunoreactivity decreased markedly in the molecular layer of the dentate gyrus. However, GFAP immunoreactivity in the CA1-3 region increased in all layers, and the cytoplasm of GFAP immunoreactive astrocytes was hypertrophied. GFAP protein levels in the aged dentate gyrus decreased; however, GFAP levels in the CA1-3 region increased. These results suggest that the morphology of astrocytes and GFAP protein levels in the hippocampal dentate gyrus and CA1 region are changed, respectively, with age.     

A case of feline temporal lobe epilepsy with hippocampal sclerosis and dentate gyrus malformation

A two-months-old, male, mixed breed cat presented with epileptic seizures. The cat was diagnosed with drug-resistant epilepsy, and died at 3-years of age. No gross lesion was found at necropsy. Histopathologically, the dentate gyrus granule cell layer of the hippocampus was irregularly arranged. Granule cells were dispersed and ectopic cells were sporadically observed in the molecular layer. The granule cells had an enlarged cytoplasm and swollen nucleus. Immunohistochemistry for NeuN and GFAP confirmed severe neuronal loss and mild gliosis in CA1. Binucleation and ischemic change were observed in the remaining pyramidal cells. This report describes a case of feline temporal lobe epilepsy and hippocampal sclerosis associated with dentate gyrus malformation.     

Regulation of bovine satellite cell proliferation and differentiation by insulin and triiodothyronine

Satellite cells activity contributes to postnatal muscle growth. Herein, we have studied the respective influence of insulin and triiodothyronine (T3) on the proliferation and differentiation of primary bovine satellite cells isolated from Semitendinosus muscle of Montbéliard steers. Under basal conditions, satellite cells proliferated until the fifth day of culture, began to fuse into myotubes and expressed differentiation markers such as connectin, myogenin, and myosin heavy chain (MHC) isoforms. Insulin behaved as an effective mitogen. Moreover, it promoted extensive myotube formation and enhanced differentiation as shown by an increase in the accumulation of differentiation markers. Maximal differentiation occurred with insulin physiological range concentrations. A delay in the stimulation of differentiation was registered with a high dose that promoted maximal proliferation. Conversely, T3 decreased cell proliferation in a dose-dependent manner. In addition, fusion and biochemical differentiation (accumulation of connectin, MyoD1, myogenin, and myosin heavy chain isoforms) were also enhanced. Bovine satellite cells seemed to respond differentially to insulin and T3 for proliferation. Interestingly, both hormones displayed a myogenic influence. Our observations suggest that both hormones could influence bovine satellite cells in vivo and contribute to the regulation of postnatal muscle growth.     

Effect of natural and synthetic retinoids on the proliferation and differentiation of three canine melanoma cell lines

The effect of two natural retinoids and synthetic retinoids with or without retinoid synergists on the proliferation and differentiation of 3 melanoma cell lines were investigated in vitro. No retinoids showed significant growth inhibitory effect on these cell lines when used alone, however, cell differentiation and significant growth inhibition were observed when treated with a combination of retinoids and a retinoid synergist. This study may suggest that, though the cells showed low susceptibilities when retinoids were treated alone, the combination of retinoids and a retinoid synergist may be effective to control the growth of canine melanoma cell lines.     

钙对体外培养大鼠成骨细胞增殖分化及细胞周期的影响

在体外培养大鼠成骨细胞的过程中,添加不同剂量的钙(0、1、2、4 mmol/L),通过检测细胞周期、细胞增殖能力、碱性磷酸酶(ALP)活性及骨桥蛋白表达,探讨了钙对成骨细胞增殖分化及细胞周期的影响.结果表明,2、4 mmol/L钙组在1～8 d均显著或极显著地促进成骨细胞增殖(P<0.05或P<0.01),1 mmol/L钙组则在5、6、8 d有显著或极显著的差异(P<0.05或P<0.01);添加不同浓度的钙除1 mmol/L组第2天外的不同时间均极显著地抑制细胞内ALP活性(P<0.01);1 mmol/L钙能极显著的使成骨细胞滞留在S期(P<0.01);添加不同浓度的钙均能使G2期显著或极显著的增加(P<0.05或P<0.01),G1期极显著的下降(P<0.01),并能极显著地诱导细胞内骨桥蛋白的表达(P<0.01).表明添加不同浓度的钙均能抑制其早期分化,促进成骨细胞的增殖,使细胞滞留在S期或G2期,诱导细胞在基质成熟期分化,有利于细胞的钙化.     

Ghrelin对鸡脂肪间充质干细胞增殖及分化为脂肪细胞的影响

为探讨Ghrelin对鸡脂肪间充质干细胞(AMSCs)增殖及分化为脂肪细胞的影响。本研究采用CCK-8法检测不同浓度的Ghrelin对AMSCs增殖的影响,再通过实时荧光定量PCR检测Ghrelin对AMSCs中c-myc和胸苷激酶1(TK1)基因mRNA表达水平的影响。然后,采用化学法对AMSCs进行成脂分化诱导,在此过程中添加不同浓度的Ghrelin,观察AMSCs的形态学变化,油红染色测定甘油三酯的累积情况,并通过实时荧光定量PCR检测脂肪细胞分化转录因子过氧化物酶体增殖剂活化受体γ(PPARγ)和CAAT/增强子结合蛋白α(C/EBPα)基因mRNA表达水平的变化。结果显示,10-7~10-11 mol/L浓度的Ghrelin均能显著或极显著促进AMSCs的增殖,其中10-9 mol/L浓度的Ghrelin的促增殖作用最强;Ghrelin也能显著或极显著升高c-myc和TK1基因mRNA的表达量。同时,Ghrelin促进AMSCs分化为脂肪细胞过程中甘油三酯的累积和脂滴的形成,显著或极显著升高PPARγ和C/EBPα基因mRNA的表达水平。结果说明,Ghrelin能够促进AMSCs增殖及分化为脂肪细胞。其分子调节机制可能是,Ghrelin通过增加c-myc的含量,进而引起TK1的活化,从而导致细胞周期的激活,促进AMSCs增殖;Ghrelin可能通过促进PPARγ和C/EBPα的表达,从而促进AMSCs分化为脂肪细胞。     

干扰DHX9对牛骨骼肌卫星细胞增殖与成肌分化的影响

为研究天冬氨酸-谷氨酸-丙氨酸-组氨酸盒解旋酶9 (DEAH (Asp-Glu-Ala-His)-box helicase 9,DHX9)对牛骨骼肌细胞增殖与分化的影响,利用已经建立的牛骨骼肌卫星细胞体外成肌分化模型,设计合成DHX9的si-RNA,采用荧光定量PCR和Western blot技术检测DHX9基因在成肌...     

Effects of fatty acid transport protein 1 on proliferation and differentiation of porcine intramuscular preadipocytes

Fatty acid transport protein 1 (FATP1) plays an important role in the fatty acid transmembrane transport and fat deposition. However, its role in porcine intramuscular preadipocytes proliferation and differentiation remain poorly understood. Here, we examined the effects of pFATP1 on porcine intramuscular preadipocytes proliferation and differentiation. Overexpression of pFATP1 in porcine intramuscular preadipocytes significantly promoted the proliferation of porcine intramuscular preadipocytes, and also significantly upregulated the expressions of peroxisome proliferator‐activated receptor γ, CCAAT enhancer binding protein α, lipoprotein lipase, fatty acid synthetase and perilipin 1. Moreover, overexpression of pFATP1 in porcine intramuscular preadipocytes significantly increased fat accumulation and downregulated β‐catenin protein expression. Overall, our results indicated that pFATP1 played an important role in porcine intramuscular preadipocytes proliferation and differentiation, and it might promote adipogenesis in porcine intramuscular preadipocytes by repressing Wnt/β‐catenin signaling pathway.     

Steroid hormone-regulated let-7b mediates cell proliferation and basigin expression in the mouse endometrium

Let-7b, one of the let-7 family members, was studied for its regulative role in endometrial cells during early pregnancy in mice. According to real-time RT-PCR analysis, the expression of let-7b in epithelial cells increased gradually from day 1 to day 4 of preimplantation stages and reached the highest level on day 4. On the other hand, the highest level of let-7b in stromal cells was observed on day 1, although the expression was decreased on day 2 and increased significantly on day 4. By in situ hybridization, let-7b was also found to express in uteri during days 6-8 of pregnancy. Endometrial cells isolated from prepubertal mice were treated with steroid hormones, progesterone (P4), estradiol (E2) and P4 plus E2. After 96 h of culture in the presence of steroid hormones, the expression levels of let-7b were increased in the endometrial cells, although significant differences were only observed after P4 treatment in stromal cells and after individual E2 and P4 treatments in the epithelial cells. In association with the increased let-7b expression, the cell proliferation slope, measured by a MTT assay, significantly decreased in the presence of P4 and P4 plus E2 compared with the nonhormone and E2 treatment groups during 72-108 h of culture. Furthermore, results from transfection of let-7b into stromal cells isolated from day 4 pregnant mice or prepubertal mice demonstrated that let-7b attenuated the proliferation during the periods of time examined. After transfection of let-7b into mouse stromal cells isolated from day 7 of pregnancy, the expression of Basigin (Bsg), a matrix metalloproteinase (MMP) inducer, was suppressed, as well as that of MMP-9. In conclusion, this study clarifies the expression pattern of let-7b in uterine epithelial and stromal cells during preimplantation stages in mice, as well as the inhibitory effect of let-7b associated with steroid hormones on stromal cell proliferation and on the expression of MMP-9.     

Effects of nuclear transfer procedures on ES cell cloning efficiency in the mouse

Enucleated oocytes receiving mouse embryonic stem (ES) cells develop into fertile young. The developmental potential to young is low, however, and the rate of postnatal death is high. We examined the effect of various nuclear transfer procedures on the in vitro and in vivo developmental potential of nuclear-transferred oocytes. The potential of oocytes receiving ES cells at M phase to develop into blastocysts after fusion by Sendai virus was high compared with that after direct injection (67% vs. 30%). The developmental potential of oocytes receiving ES cells at the M phase is higher than that of oocytes receiving ES cells at the G(1) phase (30-67% vs. 2-5%). Developmental ability to live young was low in all groups (0-4%). Different activation protocols affected the potential to develop into blastocysts to a different extent (27-62%), but did not affect the potential to develop into live young (0-3%). The present study demonstrated that the various conditions examined did not affect the potential of nuclear-transferred oocytes receiving ES cells to develop into live young or the incidence of postnatal death.     

Forkhead box O3 promotes cell proliferation and inhibits myotube differentiation in chicken myoblast cells

1. In the poultry industry, growth performance is important due to its effects on economic value. Much effort has been put forth to achieve introgression of specific genes and DNA markers related to muscle proliferation and differentiation in selective breeding approaches.

2. This study investigated the biological functions of the gene Forkhead box O3 (FOXO3) during myogenic differentiation in chicken myoblast cells. FOXO3 was downregulated in primary chicken myoblast (pCM) cells by the piggyBac transposon-mediated microRNA (miRNA) knock-down (KD) system.

3. The pCM cells that were stably integrated into the FOXO3 KD expression vector showed significant downregulation of FOXO3 protein and mRNA levels. Expression levels of paired box protein Pax7 (Pax7) and target genes such as CCAAT/enhancer binding protein beta and serum response element decreased in FOXO3 KD pCM cells. In addition, in the undifferentiated myoblast stage, there were no significant differences in cell morphology; however, proliferation rate in FOXO3 KD pCM cells was significantly lower during d 4 and 5 of in vitro culture. By contrast, when myotube differentiation was induced, FOXO3 KD pCM cells exhibited rapid initiation of myotube formation, higher expression of myogenin and desmin as myogenic indicators and a further differentiated phenotype than observed in regular pCM cells.

4. These results demonstrated that FOXO3 promotes cell proliferation and inhibits myotube differentiation in chicken myoblast cells. Therefore, the regulation of FOXO3 could be applied to improve muscle differentiation in commercial poultry.