Hepatocytes of Wistar and Sprague Dawley rats differ significantly in their central metabolism

Wistar and Sprague‐Dawley (SD) rats are most commonly used experimental rats. They have similar genetic background and are therefore, not discriminated in practical research. In this study, we compared metabolic profiles of Wistar and SD rat hepatocytes from middle (6 months) and old (23 months) age groups. Principle component analysis (PCA) on the specific uptake and production rates of amino acids, glucose, lactate and urea indicated clear differences between Wistar and SD rat hepatocytes. SD rat hepatocytes showed higher uptake rates of various essential and non‐essential amino acids, particularly in early culture phases (0‐12 h) compared to later phases (12‐24 h). SD hepatocytes seem to be more sensitive to isolation procedure and in vitro culture requiring more amino acids for cellular maintenance and repair. Major differences between Wistar and SD rat hepatocytes were observed for glucose and branched chain amino acid metabolism. We conclude that the observed differences in the central carbon metabolism of isolated hepatocytes from these two rats should be considered when using one or the other rat type in studies on metabolic effects or diseases such as diabetes or obesity.     

The Tyrosine Phosphatase STEP Is Involved in Age-Related Memory Decline

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A cAMP/PKA/Kinesin-1 Axis Promotes the Axonal Transport of Mitochondria in Aging Drosophila Neurons

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应用CRISPR/Cas9技术构建YOD1基因敲除小鼠

目的:应用CRISPR/Cas9技术构建去泛素化酶YOD1基因敲除小鼠。方法:针对YOD1基因设计单链向导RNA(sg RNA)识别序列,构建sg RNA质粒,与Cas9质粒体外转录、纯化后注射入受精卵,通过PCR和测序验证得到F0代阳性小鼠。配繁两代后,取同窝对照的野生型(WT)和敲除(KO)小鼠的主要组织器官研磨,使用免疫印迹(WB)技术检测各组织YOD1蛋白的表达,确证YOD1敲除小鼠模型是否成功建立。统计YOD1杂合子(HET)自交存活后代各基因型比例,分析是否有胚胎致死表型。解剖小鼠分析主要组织器官的表型,进一步利用H.E.染色分析KO小鼠是否存在自发的病理改变。通过血糖耐受实验(GTT)分析KO小鼠的血糖调控能力。结果:基因组测序和WB检测结果显示KO小鼠中YOD1被明显敲除,YOD1敲除小鼠模型成功建立。YOD1杂合子自交后代各基因型比例符合孟德尔定律,提示KO小鼠非胚胎致死。YOD1敲除小鼠肝脏显著小于WT小鼠。GTT结果表明敲除YOD1不影响小鼠的血糖稳态。结论:应用CRISPR/Cas9技术成功构建YOD1基因敲除小鼠。KO小鼠正常出生,无任何胚胎发育缺陷。与WT小鼠相比,KO小鼠肝脏显著减小,但无显著的自发病理变化,KO小鼠血糖控制亦无显著差异。     

Atp1a3‐deficient heterozygous mice show lower rank in the hierarchy and altered social behavior

Atp1a3 is the Na‐pump alpha3 subunit gene expressed mainly in neurons of the brain. Atp1a3‐deficient heterozygous mice (Atp1a3^+/?) show altered neurotransmission and deficits of motor function after stress loading. To understand the function of Atp1a3 in a social hierarchy, we evaluated social behaviors (social interaction, aggression, social approach and social dominance) of Atp1a3^+/? and compared the rank and hierarchy structure between Atp1a3^+/? and wild‐type mice within a housing cage using the round‐robin tube test and barbering observations. Formation of a hierarchy decreases social conflict and promote social stability within the group. The hierarchical rank is a reflection of social dominance within a cage, which is heritable and can be regulated by specific genes in mice. Here we report: (1) The degree of social interaction but not aggression was lower in Atp1a3^+/? than wild‐type mice, and Atp1a3^+/? approached Atp1a3^+/? mice more frequently than wild type. (2) The frequency of barbering was lower in the Atp1a3^+/? group than in the wild‐type group, while no difference was observed in the mixed‐genotype housing condition. (3) Hierarchy formation was not different between Atp1a3^+/? and wild type. (4) Atp1a3^+/? showed a lower rank in the mixed‐genotype housing condition than that in the wild type, indicating that Atp1a3 regulates social dominance. In sum, Atp1a3^+/? showed unique social behavior characteristics of lower social interaction and preference to approach the same genotype mice and a lower ranking in the hierarchy.     

Single point mutation on the gene encoding dysbindin results in recognition deficits

The dystrobrevin‐binding protein 1 (DTNBP1) gene is a candidate risk factor for schizophrenia and has been associated with cognitive ability in both patient populations and healthy controls. DTNBP1 encodes dysbindin protein, which is localized to synaptic sites and is reduced in the prefrontal cortex and hippocampus of patients with schizophrenia, indicating a potential role in schizophrenia etiology. Most studies of dysbindin function have focused on the sandy (sdy) mice that lack dysbindin protein and have a wide range of abnormalities. In this study, we examined dysbindin salt and pepper (spp) mice that possess a single point mutation on the Dtnbp1 gene predicted to reduce, but not eliminate, dysbindin expression. By western blot analysis, we found that spp homozygous (spp ?/?) mutants had reduced dysbindin and synaptosomal‐associated protein 25 (SNAP‐25) in the prefrontal cortex, but unaltered levels in hippocampus. Behaviorally, spp mutants performed comparably to controls on a wide range of tasks assessing locomotion, anxiety, spatial recognition and working memory. However, spp ?/? mice had selective deficits in tasks measuring novel object recognition and social novelty recognition. Our results indicate that reduced dysbindin and SNAP‐25 protein in the prefrontal cortex of spp ?/? is associated with selective impairments in recognition processing. These spp mice may prove useful as a novel mouse model to study cognitive deficits linked to dysbindin alterations. Our findings also suggest that aspects of recognition memory may be specifically influenced by DTNBP1 single nucleotide polymorphisms or risk haplotypes in humans and this connection should be further investigated.     

CD36 initiates the secretory phenotype during the establishment of cellular senescence

Cellular senescence is a unique cell fate characterized by stable proliferative arrest and the extensive production and secretion of various inflammatory proteins, a phenomenon known as the senescence‐associated secretory phenotype (SASP). The molecular mechanisms responsible for generating a SASP in response to senescent stimuli remain largely obscure. Here, using unbiased gene expression profiling, we discover that the scavenger receptor CD36 is rapidly upregulated in multiple cell types in response to replicative, oncogenic, and chemical senescent stimuli. Moreover, ectopic CD36 expression in dividing mammalian cells is sufficient to initiate the production of a large subset of the known SASP components via activation of canonical Src–p38–NF‐κB signaling, resulting in the onset of a full senescent state. The secretome is further shown to be ligand‐dependent, as amyloid‐beta (Aβ) is sufficient to drive CD36‐dependent NF‐κB and SASP activation. Finally, loss‐of‐function experiments revealed a strict requirement for CD36 in secretory molecule production during conventional senescence reprogramming. Taken together, these results uncover the Aβ–CD36–NF‐κB signaling axis as an important regulator of the senescent cell fate via induction of the SASP.     

β-aminoisobutyric Acid,l-BAIBA,Is a Muscle-Derived Osteocyte Survival Factor

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Age-Associated Impairments in Mitochondrial ADP Sensitivity Contribute to Redox Stress in Senescent Human Skeletal Muscle

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