醛固酮对3T3-L1前脂肪细胞与脂肪细胞内脂素表达和分泌的影响

目的:探讨醛固酮对3T3-L1前脂肪细胞和脂肪细胞内脂素基因表达和蛋白分泌的影响。方法:10-8和10-6mol/L醛固酮加或不加10-6mol/L安体舒通分别干预3T3-L1前脂肪细胞和脂肪细胞24h和48h,用实时RT-PCR测定内脂素和盐皮质激素受体(MR)mRNA的表达,酶联免疫法测定培养液中内脂素的浓度。结果:醛固酮作用于3T3-L1前脂肪细胞,内脂素mRNA表达减少,培养液中蛋白浓度变化不明显,MR mRNA表达增高。醛固酮作用于脂肪细胞,内脂素mRNA表达和蛋白浓度均降低,MR mRNA表达增高。安体舒通在一定程度上可对抗醛固酮对内脂素的抑制作用。结论:醛固酮抑制3T3-L1脂肪细胞内脂素的基因表达和分泌。     

脂联素siRNA对3T3-L1细胞基础葡萄糖转运的影响

目的：构建携带小鼠脂联素（Acrp30）siRNA腺病毒载体，并检测其对小鼠脂肪细胞Acrp30表达以及对3T3-L1脂肪细胞基础葡萄糖转运的影响。方法:设计并化学合成小鼠脂肪细胞Acrp30 siRNA片段，将其亚克隆入AdEaxy XL 腺病毒载体系统，在293细胞内包装扩增为重组腺病毒。用此重组腺病毒感染3T3-L1脂肪细胞，用RT-PCR和ELISA检测其Acrp30 mRNA和蛋白表达。采用2-Deoxy-［3H］D-glucose掺入法测定脂肪细胞葡萄糖转运。结果:设计并构建了小鼠Acrp30 基因特异性siRNA腺病毒载体，该载体感染脂肪细胞后，能显著抑制Acrp30 mRNA和蛋白表达，影响3T3-L1脂肪细胞基础葡萄糖的转运，与对照组相比，差异显著(P<0.05)。结论:构建的Acrp30 基因特异性siRNA腺病毒载体能有效地抑制脂联素在3T3-L1脂肪细胞中的表达，从而影响3T3-L1脂肪细胞基础葡萄糖转运。     

胰岛素和人参皂甙 Rg1对脂联素mRNA 表达的影响

目的:探讨不同浓度的胰岛素和人参皂甙Rg1对体外3T3-L1脂肪细胞脂联素(adiponectin) mRNA 表达的影响。方法:通过不同浓度胰岛素和Rg1与3T3-L1脂肪细胞共同培养，以β-actin为内对照，半定量逆转录PCR法测定脂联素 mRNA表达。结果:随着胰岛素浓度的升高，脂联素 mRNA 表达逐渐降低，在胰岛素浓度 ≥100 nmol/L 时具有显著差异（P<0.05）;40 mg/L Rg1能有效逆转高胰岛素对脂联素mRNA 表达的抑制作用（P<0.05）。结论:体外高胰岛素水平可使3T3-L1细胞脂联素表达下降，Rg1可逆转体外高胰岛素降低脂联素表达的作用。     

替米沙坦对体外培养脂肪细胞脂联素表达的影响

背景:脂联素对胰岛素抵抗、代谢综合征有着重要的调节作用,其合成受过氧化物酶体增殖物活化受体γ活性的调节,研究表明部分血管紧张素受体拮抗剂可通过激活过氧化物酶体增殖物活化受体γ影响脂联素代谢,但具体机制尚不清楚。目的:探讨替米沙坦对脂肪细胞脂联素表达和分泌的影响,并与坎地沙坦进行比较。方法:体外培养、诱导分化3T3-L1脂肪细胞,分别用空白培养液、坎地沙坦(10μmol/L)和替米沙坦(10μmol/L)干预3T3-L1脂肪细胞,采用RT-PCR法、Western blot法和ELISA法检测脂肪细胞脂联素mRNA和蛋白表达及培养液中脂联素的分泌水平。结果与结论:与空白组和坎地沙坦组相比,替米沙坦组脂肪细胞脂联素的mRNA和蛋白表达水平明显增加(P0.05或P0.01),但各组间脂肪细胞培养液中脂联素的分泌水平差异无显著性意义(P0.05)。说明替米沙坦可以明显增加脂肪细胞脂联素的表达,但并不增加脂联素的分泌水平,其促进脂联素表达的作用优于坎地沙坦。     

血管钠肽减轻MPP+所致多巴胺神经元损伤*

 目的：探讨血管钠肽（vasonatrin peptide,VNP）的神经保护效应。方法：原代培养取自小鼠中脑腹侧的多巴胺神经元,暴露于1-甲基-4-苯基吡啶离子（1-methyl-4-phenylpyridinium,MPP+）。采用细胞活力分析和免疫荧光染色评价VNP对MPP+神经毒性的影响,并应用多种阻断剂和激动剂探讨VNP神经效应的机制。结果：MPP+造成多巴胺神经元损伤,VNP增强多巴胺神经元的细胞活力,增加神经元轴突数目和长度。VNP还可抑制MPP+造成的神经元β-微管蛋白III解聚。另外,VNP显著升高细胞内cGMP水平。VNP的效应可以被8-Br-cGMP（一种膜通透性的cGMP类似物）所模拟,被HS-142-1［鸟苷酸环化酶偶联的钠尿肽受体（NPR）的阻断剂］或KT-5823［cGMP依赖性蛋白激酶(PKG)的阻断剂］所阻断。结论：VNP通过NPR/cGMP/PKG通路减轻MPP+的神经毒性,提示VNP可能成为一种新的有效药物,治疗帕金森病的神经退行性病变。     

甘露聚糖结合凝集素(MBL)对3T3-L1前脂肪细胞成脂分化的调节作用及机制

目的研究甘露聚糖结合凝集素(mannan-binding lectin,MBL)对3T3-L1前脂肪细胞成脂分化的调节及其机制。方法体外诱导3T3-L1前脂肪细胞成脂分化,同时给予不同浓度的MBL(0、1、10、20μg/ml)干预。CCK-8法检测细胞增殖能力变化,油红O染色和细胞内甘油三酯含量测定法分析脂质积累情况。Western blot及qRT-PCR检测脂肪细胞成脂分化相关因子PPARγ及C/EBPα的蛋白质及mRNA表达水平。Western blot分析脂肪合成调控信号分子Akt的表达及磷酸化。结果实验组各浓度MBL(0、1、10、20μg/ml)对3T3-L1前脂肪细胞增殖都无影响。3T3-L1前脂肪细胞诱导分化3 d,甘油三酯检测发现MBL处理组细胞内甘油三酯水平下降,并呈剂量依赖关系;油红O染色结果进一步显示,MBL处理组的脂滴数量显著减少,吸光度值也显著降低,同样呈现浓度依赖关系。Western blot及qRT-PCR检测结果证实,MBL处理组PPARγ和C/EBPα的蛋白质及mRNA表达水平均显著下降,呈剂量依赖性。在MBL干预下,Akt的磷酸化水平也明显下调。结论MBL通过Akt信号通路调控3T3-L1前脂肪细胞的成脂分化。     

小檗碱激活AMPK抑制3T3-L1脂肪细胞分化

目的 探讨小檗碱对3T3-L1脂肪分化的作用是否与激活腺苷酸活化蛋白激酶（AMPK）有关.方法 在3T3-L脂肪细胞分化全程加入小檗碱,以油红O染色检测3T3-L1脂肪细胞胞浆中脂肪的堆积,实时定量PCR检测过氧化物酶体增殖物激活受体γ2（PPARγ2）、CCAAT增强子结合蛋白α（CEBPα）和AMPK的mRNA表达,以Western印迹法检测AMPK和乙酰辅酶A羧化酶（ACC）的磷酸化水平.结果 小檗碱剂量依赖性地抑制3T3-L1脂肪细胞分化,10 μmol/L小檗碱几乎完全抑制胞浆中脂肪的堆积.5 μmol/L小檗碱在脂肪细胞诱导分化1、3、5、7d后均显著降低CEBPα mRNA表达（P〈0.05或P〈0.01）,诱导分化3、5、7d时显著降低PPARγ2的mRNA表达（P〈0.05或P〈0.01）.AMPK的mRNA水平在分化过程中未受小檗碱的明显影响,而小檗碱明显增加其蛋白磷酸化水平,其下游靶基因ACC磷酸化水平也明显增加.结论 小檗碱抑制3T3-L1脂肪细胞的分化可能与其激活AMPK有关.     

resistin基因过表达影响3T3-L1脂肪细胞的脂质代谢

目的观察resistin基因过表达对3T3-L1脂肪细胞的脂质代谢、糖代谢的影响。方法构建大鼠resistin真核表达载体并转染3T3-L1前体脂肪细胞,获得稳定表达resistin基因的细胞株;采用油红O染色,观察脂肪细胞分化及脂质积聚情况;采用逆转录PCR技术,检测脂肪细胞分化标志基因及葡萄糖转运体4（glucose transporter4,GLUT4）基因表达变化;采用全自动生化仪比色法,检测脂肪细胞内甘油三酯（triglyceride,TG）、游离脂肪酸（free fatty acids,FFAs）的含量变化。结果（1）resistin基因过表达脂肪细胞中,脂滴出现时间提前,且细胞内布满了小而多的圆形脂滴;（2）resistin基因过表达脂肪细胞中,分化中、晚期标志基因C/EBPα、FAS的mRNA表达水平明显上调,分化早期标志基因Pref-1的表达则明显下调;（3）re-sistin基因过表达脂肪细胞中,胞质内TG、FFAs含量均显著增加;（4）resistin基因过表达脂肪细胞中,分化第2、4、8d的GLUT4基因mRNA表达水平间无显著变化,与正常脂肪细胞中的表达水平差异也无统计学意义。结论resistin基因过表达能够显著干扰3T3-L1脂肪细胞的脂质代谢,有助于肥胖和胰岛素抵抗的发生,而并不影响GLUT4基因的表达。     

GLP-1受体激动剂对肥胖小鼠脂肪组织的脂解作用及机制探讨

目的:探讨胰高血糖素样肽1(GLP-1)受体激动剂艾塞那肽(exendin-4)对肥胖小鼠脂肪组织的作用及机制。方法:8周龄C57BL/6J小鼠高脂喂养12周后随机分为艾塞那肽组和生理盐水对照组,另设正常饮食组。取附睾旁脂肪检测sirtuin 1(SIRT1)、脂肪甘油三酯脂酶(ATGL)、肿瘤坏死因子α(TNF-α)及脂联素mRNA的表达。Exendin-4或联合SIRT1激动剂/抑制剂处理3T3-L1脂肪细胞24 h;小鼠胚胎成纤维细胞(MEF)诱导成脂肪细胞后exendin-4干预24 h;检测SIRT1、ATGL和激素敏感性脂酶(HSL)的蛋白表达水平。结果:与生理盐水对照组相比,艾塞那肽组小鼠附睾旁脂肪量、空腹血糖及血甘油三酯水平降低(均P0.05),体重减轻,血TNF-α水平降低。艾塞那肽干预后,肥胖小鼠脂肪组织SIRT1、ATGL和脂联素mRNA表达明显上调,TNF-αmRNA表达明显下调(P0.05)。Exendin-4剂量依赖性促进3T3-L1脂肪细胞SIRT1、ATGL和HSL脂解相关蛋白的表达。联合SIRT1激动剂后,脂滴数量减少,上述脂解相关蛋白的表达上调。联合SIRT1抑制剂后上述作用减弱。敲除SIRT1后MEF脂肪细胞内脂滴增大,数量增多,exendin-4促进脂解的作用消失。结论:艾塞那肽通过激活SIRT1促进肥胖小鼠脂肪组织脂解作用。     

果糖通过激活Akt信号通路促进3T3-L1细胞的脂肪分化

目的:研究果糖(fructose)对3T3-L1前脂肪细胞分化过程的影响及其作用机制。方法:对体外培养的3T3-L1前脂肪细胞给予鸡尾酒法诱导脂肪分化,并使用1 g/L的果糖进行诱导干预。油红O染色法定量分析细胞内的脂质含量;RT-qPCR法检测脂肪分化过程中脂滴包被蛋白2(Plin2)、CCAAT/增强子结合蛋白(C/EBP)α和C/EBPβ的mRNA表达水平;Western blot检测脂肪分化标志蛋白过氧化物酶体增殖物激活受体γ(PPARγ)和脂肪细胞蛋白2(αP2)的蛋白表达水平。结果:与单纯用分化培养基(DM)的对照组相比,实验(DM+fructose)组的脂肪细胞体积及胞质内脂滴积累量显著增加,脂肪分化标志蛋白PPARγ和aP2的表达水平显著上调(P0.01),Plin2、C/EBPα和C/EBPβ的mRNA表达水平亦显著上调(P0.05)。此外,加入果糖之后Akt信号通路中的关键分子Akt的磷酸化水平显著增加(P0.01),加入Akt特异性阻断剂之后,PPARγ和aP2的表达水平显著下调。结论:果糖能够促进3T3-L1细胞的脂肪分化,可能是通过激活Akt信号通路实现的。     

On the relationship of P3a and the Novelty-P3

Deviant stimuli give rise to a late positive ERP component with latencies from 250 to 400 ms. Target deviants elicit a P300 with maximum amplitude over parieto-central recording sites while the 'P300' elicited by deviant nontarget stimuli occurs somewhat earlier and shows a more frontally-oriented scalp distribution. Two varieties of frontal P300s have been described, elicited either by rare stimuli (target or nontarget) presented in a two-stimulus oddball task (P3a) or by infrequent, unrecognizable stimuli presented in the context of a three-stimulus oddball task (Novelty-P3). The Novelty-P3 has been observed in a number of subsequent studies; the P3a has not been extensively studied and both its significance and existence have been called into question. The present report describes a replication of two prototypical studies with 'frontal' P3s observed in each context. Application of factor analysis to the two sets of ERP waveforms does not support a distinction between these two components.     

Covalent binding of guanine nucleotides to the CD3-γ chain of the T cell receptor/CD3 complex

In a search for proteins involved in signal transduction through the T cell receptor (TcR/CD3 complex), a recently developed highly efficient method for labeling of nucleotide binding proteins in permeabilized cells was applied. Here, we report that human CD3-γ could be labeled by periodate-oxidized [α-³²P] GTP (GTP_oxi). In contrast to GTP_oxi labeling of CD3-ξ, (Peter, M. E., Hall, C, Ruhlmann, A., Sancho, J. and Terhorst, C, EMBOJ. 1992. 11: 933), GTP-specific labeling of CD3-γ reached a maximum when nucleotides were added 60 min prior to the cross-linking reaction. As CD3-γ did not contain a known consensus sequence for nucleotide binding and since labeling kinetics of CD3-γ coincided with those of cytosolic GTP-binding proteins, labeling may have been caused by a GTP-binding protein. This putative protein was not T cell specific because labeling of CD3-γ could also be achieved when expressed in the endoplasmic reticulum of Chinese hamster ovary (CHO) cells. In CHO cells, labeling by GTP_oxi took place only when CD3-γ was associated with CD3-ξ, whereas labeling could not be established upon association of CD3-γ with CD3-δ or TcR α. The observation that CD3-γ was labeled without leaving the endoplasmic reticulum led to the hypothesis that the association of CD3-γ with a GTP-binding protein might be involved in an early step of the TcR/CD3 complex formation or transport.     

14-3-3 Protein isoforms and atypical patterns of the 14-3-3 assay in the diagnosis of Creutzfeldt-Jakob disease

A positive 14-3-3 assay is a criterion for probable Creutzfeldt-Jakob disease (CJD). Cerebrospinal fluid (CSF) 14-3-3 is usually detected by immunoblot using an antibody that recognizes all of the 14-3-3 isoforms. In a few cases, the antibody recognizes an inferior band and this pattern is associated with false positive results. We analyzed 43 CSF (26 CJD, 17 controls) samples using antibodies against specific isoforms (beta, epsilon, gamma, tau, xi) and compared the results with those obtained with the standard antibody. The anti-gamma and anti-beta antibody achieved similar results but the presence of atypical patterns made the standard antibody more accurate for the CJD diagnosis. To study the nature of the inferior band, CSF samples were probed with antibodies against light chain immunoglobulins, and immunoblots of human IgG with the standard antibody. The experiments suggested a cross-reaction of the anti-14-3-3 antibody with light chain immunoglobulins.     

Partial deletion of the short arm of chromosome 3: further delineation of the 3p25 - 3pter syndrome

A male newborn with partial deletion of the short arm of chromosome 3 is described. The patient shares most of the features with the previously reported cases. In addition, cardiac, skeletal and gastrointestinal anomalies not previously reported are described. These characteristics may help in further delineation of the syndrome.     

Comparison of the effects of interleukin-1α, interleukin-lβ and interferon-γ-inducing factor on the production of interferon-γ by natural killer

Interferon-γ inducing factor (IGIF) is a recently identified cytokine which stimulates the production of interferon-γ (IFN-γ) by T cells and enhances natural killer (NK) cell cytolytic activity. Protein fold recognition, structure prediction and comparative modeling have revealed that IGIF is a member of the interleukin (IL)-1 cytokine family and has prompted the designation IL-1γ. Here we report functional similarities between members of the IL-1 family by comparing the effects of IL-1α, IL-1β and IGIF on NK cell production of IFN-γ. All three IL-1 types enhanced NK cell production of IFN-γ when induced by IL-2 or IL-12, although at high concentrations (>10 ng/ml), IGIF was five- to tenfold more potent than IL-1α or IL-1β. This effect correlated with enhanced levels of mRNA for IFN-γ when NK cells were stimulated with IGIF plus IL-12. In contrast to IL-12 and IL-2, the ability of IGIF to stimulate NK cell production of IFN-γ was not increased by IL-1α or IL-1β. The ability of IGIF to enhance IFN-γ production was independent of the type I and type II IL-1 receptors or the IL-1R accessory protein. Together, these results identify IGIF as a potent stimulator of NK cell production of IFN-γ and demonstrate that the effect of IGIF on NK cell production of IFN-γ is similar to that of IL-1α and IL-1β but distinct from that of IL-12.     

Electron-microscopic characteristics of the dynamics of thymidine-H3 and uridine-H3 in the mouse epidermis

The dynamics of distribution of uridine-H³ and thymidine-H³ in the epidermis of C57BL mice was studied electron-microscopically between 2 and 24 h after their separate intraperitoneal injection. A high rate of incorporation of both labeled nucleosides was discovered and their localization was found to depend on the time of injection. Depending on the character of their distribution and the rate of incorporation into the epidermis three zones of active protein synthesis can be distinguished: the boundary zone between the epidermis and dermis, the layer of basal cells, and the granular layer. The character of distribution of the label in the late period after injection confirms electron-microscopic data on the active role of the nucleus and the cytoplasmic ribosomes in fibril synthesis in the basal and prickle cells and in keratohyalin formation in the cells of the granular layer. By determining the hourly changes in the distribution of the labels the stages of transport of the injected nucleosides or their metabolites could be followed from the subepidermal region into the cells of the epidermis.Scientific-Research Laboratory, Ministry of Health of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 78, No. 9, pp. 111–115, September, 1974.