吸烟对大鼠骨骼肌胰岛素受体底物2基因表达的影响

应用RT-PCR和免疫组化检测被动吸烟大鼠骨骼肌胰岛素受体底物2(IRS-2)mRNA和蛋白表达变化,结果显示吸烟使正常组、高脂饲养组大鼠骨骼肌IRS-2 mRNA(0.27±0.02 vs 0.41±0.25,0.40±0.04 vs 0.51±0.02)及蛋白(2.91±0.42 vs 4.90±0.29,2.43 vs 0.36±3.80+0.30)表达显著降低(均P<0.01).糖尿病吸烟组大鼠与对照组则差异无统计学意义(P>0.05),提示IRS-2基因表达的变化可能在吸烟致大鼠胰岛素抵抗发生机制中起一定的作用.     

胰岛素受体底物及其基因多态性与胰岛素抵抗

胰岛素受体底物(IRS)是胰岛素信息传递的重要介质。IRS-1主要介导胰岛素在外周组织的效应,调节β细胞分泌;IRS-2主要介导胰岛素在肝脏的作用,对β细胞发育有重要影响;IRS-3、IRS-4的作用尚存争论。IRS-1、IRS-2基因多态性可致肝脏、外周组织及β细胞胰岛素抵抗;IRS-3、IRS-4基因多态性尚缺乏相关的报道。     

OLETF大鼠肝脏、肌肉、脂肪组织中胰岛素受体底物1的蛋白表达

各种靶组织的胰岛素抵抗和胰腺 β细胞分泌功能受损是导致 2型糖尿病的主要原因〔1〕,但机制不明 ;为探讨 2型糖尿病胰岛素抵抗的分子机制 ,以一种自发发病的 2型糖尿病模型—ＯＬＥＴＦ大鼠为对象 ,研究其肝脏、骨胳肌、脂肪组织内胰岛素信号传导分子胰岛素受体底物 1(ＩＲＳ 1)蛋白表达水平。一、材料和方法1.实验动物 :ＯＬＥＴＦ大鼠 (由日本大冢制药公司研究所提供 4周龄雄性大鼠 ,在北京医科大学实验动物中心普通饲料喂养至 16周 )为研究对象 ;Ｗｉｓｔａｒ大鼠为对照组。2 .口服葡萄糖耐量试验〔2〕:试验前禁食 14小时 ,先取空腹眼眶…     

胰岛素抵抗的分子机制——胰岛素受体底物-1丝氨酸磷酸化和p85α表达增加

尽管胰岛素抵抗（IR）与糖尿病（DM），肥胖，高血压和心血管疾病关系密切，但其分子机制并不完全清楚。在细胞水平，IR是指胰岛素信号传导能力的减低，这种信号传导从胰岛素受体向下到达胰岛素作用的终未底物，涉及到细胞功能的多种代谢和促有丝分裂方面。     

胰岛素受体底物及其基因多态性与胰岛素抵抗

胰岛素受体底物(IRS)是胰岛素信息传递的重要介质。IRS-1主要介导胰岛素在外周组织的效应，调节β细胞分泌；IRS-2主要介导胰岛素在肝脏的作用，对β细胞发育有重要影响；IRS-3、IRS-4的作用尚存争论。IRS-1、IRS-2基因多态性可致肝脏、外周组织及β细胞胰岛素抵抗；IRS-3、IRS-4基因多态性尚缺乏相关的报道。     

胰岛素对人成骨细胞胰岛素受体底物-2的作用

胰岛素受体底物(IRS)是胰岛素受体、胰岛素样生长因子 1受体酪氨酸蛋白激酶的主要底物 [1]。IRS 2在糖尿病的发生和发展中起着一定作用,它调节胰岛β细胞数目及功能 [2]。IRS 2还是骨代谢的调节因子,在胰岛素、胰岛素样生长因子 1等骨代谢因子的信号传递中起重要作用,IRS 2     

吸烟减少大鼠骨骼肌胰岛素受体底物1 mRNA和蛋白表达

应用RT-PCR及免疫组化技术分别检测实验大鼠后肢骨骼肌胰岛素受体底物1 mRNA及蛋白的表达。结果提示正常吸烟组、高脂饲养吸烟组及糖尿病吸烟组大鼠骨骼肌胰岛素受体底物1基因mRNA的表达及蛋白含量显著低于各自对照组（P〈0．05或P〈0．01），这可能是吸烟导致胰岛素抵抗的分子机制之一。     

胰岛素受体底物-1与骨代谢

胰岛素受体底物(insulin receptor substrate,IRS)是胰岛素信号传导通路中受体后水平的重要信号蛋白。IRS-1对骨骼生长、骨转换以及骨折愈合等均具有重要作用,为代谢性骨病和骨质疏松的防治提供了新思路。     

胰岛素受体底物在2型糖尿病患者脂肪组织中的表达及意义

用Western印迹技术检测2型糖尿病患者腹部皮下脂肪组织内胰岛素受体底物1与2(IRS-1和IRS-2)的蛋白表达。结果提示2型糖尿病患者脂肪组织IRS-1蛋白表达减少和IRS-2蛋白表达未变。IRS-2可能是主要的docking蛋白，并可能是引起2型糖尿病高胰岛素血症及胰岛素抵抗的因素之一。     

胰岛素受体底物及其在支气管哮喘发病机制中的作用

支气管哮喘(简称哮喘)是由多种因素引起的疾病,目前公认的发病机制是气道炎症假说.近来研究表明,胰岛素受体底物(insulin receptor substrate,IRS)在哮喘发病中也起很大作用,通过探索IRS如IRS-1、IRS-2和SHc(SHc是含有SH结构域的基因编码的蛋白产物),尤其是SHc在哮喘中的作用机制,将有望在哮喘治疗上提出新的治疗方向.     

胃旁路术后IRS-1和IRS-2的表达变化对糖尿病大鼠空腹血糖和胰岛素抵抗的影响及作用机制

目的探讨Roux-en-Y胃旁路术（RYGB）后胰岛素受体底物（IRS）-1和IRS-2的表达变化对糖尿病大鼠空腹血糖和胰岛素抵抗的影响及其作用机制。 方法用随机数字表法将30只糖尿病模型的Wistar大鼠分为RYGB组、假手术组和饮食对照组。另选取10只同周龄的正常Wistar大鼠为对照组。RYGB组接受RYGB,假手术组在相同位置处切开胃壁和空肠后行原位缝合,饮食对照组的进食量为RYGB组前1天的进食量,空白对照组自由进食普通饲料。于术前和术后1、2、3、4周检测空腹血糖（FPG）和空腹胰岛素（FIns）水平,并计算胰岛素抵抗指数（HOMA-IR）。其后处死大鼠,取骨骼肌、肝脏和胰腺组织。采用Western blot技术检测各组大鼠骨骼肌和肝脏中IRS-1和IRS-2的表达情况,采用免疫组化方法检测胰腺IRS-2的表达情况。4组数据的比较采用单因素方差分析,组间两两比较采用LSD-t检验;组内两组数据的比较采用配对t检验;4组胰腺组织IRS-2阳性表达率的比较采用χ²检验。 结果术后第4周,RYGB组大鼠的FPG水平较术前明显降低（t=30.617,P<0.05）,低于同期的假手术组和饮食对照组（LSD-t_假手术组=12.112,LSD-t_{饮食对照组}=10.095,P值均<0.05),与空白对照组比较差异无统计学意义（LSD-t=0.347,P>0.05）;RYGB组大鼠的HOMA-IR值也较术前明显下降（t=8.631,P<0.05）,低于同期假手术组和饮食对照组（LSD-t_假手术组=7.713,LSD-t_{饮食对照组}=7.931,P值均<0.05）,与空白对照组比较差异无统计学意义（LSD-t=0.822,P>0.05）。手术4周后,RYGB组大鼠肌肉组织中IRS-1和其磷酸化的p-IRS-1表达水平明显高于假手术组和饮食对照组（P<0.05）;RYGB组大鼠肝脏组织中IRS-2的表达水平明显低于假手术组和饮食对照组（P<0.05）,稍高于空白对照组;RYGB组大鼠胰腺细胞中IRS-2的阳性表达率为76%,明显高于饮食对照组的2%,假手术组的3%和空白对照组的44%（χ²_{饮食对照组}=230.181,χ²_假手术组=222.994,χ²_{空白对照组}=42.667,P值均<0.05）。 结论RYGB能引起相应靶器官内IRS-1和IRS-2的表达变化,这可能是改善2型糖尿病胰岛素抵抗和降低空腹血糖水平的机制之一。     

Distribution and subcellular localization of glucocorticoid receptor-immunoreactive neurons in the developing and adult male zebra finch brain

Stress has long lasting effects on physiology, development, behavior, reproductive success and the survival of an individual. These effects are mediated by glucocorticoids, such as corticosterone, via glucocorticoid receptors (GR), however the exact mechanisms underlying these effects are unknown. GR have been widely studied in mammals but little is known about GR in other vertebrate groups, especially songbirds. We investigated the distribution, quantity, and subcellular-localization of GR-immunoreactive (GRir) neurons in the brains of male zebra finches on P10 (post-hatch day 10, song nuclei formed), and in adulthood (post-hatch day 90 or older) using immunohistochemistry. GRir neurons were widely distributed in the brains of male zebra finches including two song nuclei HVC (acronym is a proper name) and RA (nucleus robustus arcopallii) and brain regions including HP (hippocampal formation), BSTl (lateral part of the bed nucleus of the stria terminalis), POM (nucleus preopticus medialis), PVN (nucleus paraventricularis magnocellularis), TeO (optic tectum), S (nucleus of the solitary tract), LoC (Locus coeruleus). Distribution did not vary at the two age points examined, however there were significant differences in staining intensity. Subcellular GR-immunoreactivity patterns were classified as cytoplasmic, nuclear, or both (cytoplasmic and nuclear) and there were significant differences in the overall number of GRir neurons and neurons with both nuclear and cytoplasmic staining in P10 and adult brains. However, there were no significant differences in the percentage of subcellular GR immunoreactivity patterns between P10 and adults. Our study of GRir neuronal distribution in the zebra finch brain may contribute towards understanding of the complex and adverse effects of stress on brain during two different stages of life history.     

小胶质细胞Toll样受体4信号转导通路与中枢神经系统损伤

中枢神经系统损伤机制复杂,小胶质细胞参与了多种中枢神经系统疾病和损伤过程.Toll样受体4(Toll-like receptor 4,TLR4)可介导小胶质细胞的活化和炎性细胞因子的表达,是小胶质细胞发挥功能的重要受体蛋白之一.文章简要介绍了小胶质细胞TLR4信号通路在中枢神经系统损伤中的作用.     

Antineoplastic effect of rapamycin is potentiated by inhibition of IRS-1 signaling in prostate cancer cells xenografts

Proper activation of phosphoinositide 3-kinase-Akt pathway is critical for the prevention of tumorigenesis. Recent data have characterized a negative feedback loop, wherein mammalian target of rapamycin (mTOR) blocks additional activation of the Akt/mTOR pathway through inhibition insulin receptor substrate 1 (IRS-1) function. However, the potential of IRS-1 inhibition during rapamycin treatment has not been examined. Herein, we show that IRS-1 antisense oligonucleotide and rapamycin synergistically antagonize the activation of mTOR in vivo and induced tumor suppression, through inhibition of proliferation and induction of apoptosis, in prostate cancer cell xenografts. These data demonstrate that the addition of agents that blocks IRS-1 potentiate the effect of mTOR inhibition in the growth of prostate cancer cell xenografts.     

Distribution of peptide-containing nerve fibres in achalasia of the oesophagus

In this study the innervation of the normal human oesophagus was compared with samples taken from 12 patients undergoing Heller's cardiomyotomy for achalasia. The distribution of all nerve fibres in the oesophageal wall was revealed by immunoreactivity to neuron specific enolase and subpopulations of nerve fibres were revealed by immunoreactivity to vasoactive intestinal peptide, neuropeptide Y, enkephalin and substance P. In healthy oesophagus, many nerve fibres immunoreactive for vasoactive intestinal peptide and neuropeptide Y were present in the circular and longitudinal muscle layers of the oesophageal wall and in the cardia of the stomach, whereas fibres immunoreactive for enkephalin and substance P were uncommon. Neuropeptide Y-reactive fibres were commonly seen around blood vessels. In the myenteric plexus cell bodies reactive for vasoactive intestinal peptide and neuropeptide Y were prevalent, as were varicose and non-varicose fibres. In contrast, samples from patients with achalasia revealed few nerve fibres immunoreactive for vasoactive intestinal peptide or neuropeptide Y in either circular or longitudinal muscle, suggesting damage to the inhibitory motor neurons to the muscle layers. Very few fibres were found that were reactive for neuron-specific enolase, indicating that other fibre populations (e.g. excitatory cholinergic motor neurons) are also damaged in achalasia. These abnormalities were observed in biopsies from both the constricted and dilated portions of the oesophagus, but the pattern of innervation in the gastric cardia was normal. Myenteric ganglion cells were seen in the oesophagus in only two patients and varicose nerve fibres in the myenteric plexus were uncommon. Neuropeptide Y-reactive perivascular nerve fibres were still found in achalasia as well as non-varicose nerve fibres in the myenteric plexus. These findings indicate damage to all intrinsic neurons in the oesophageal wall in achalasia; however, extrinsic nerve fibres appear to be intact.     

Insulin-independent and wortmannin-resistant targeting of IRS-3 to the plasma membrane via its pleckstrin homology domain mediates a different interaction with the insulin receptor from that of IRS-1

Aims/hypothesis: In primary adipocytes, although IRS-1 and IRS-3 are expressed in comparable amounts, these proteins manifest distinct distribution and significance in insulin signalling. We investigated the molecular basis of the difference between these two proteins. Methods: In Cos-1 cells transiently expressing rat IRS-1, IRS-3, or chimeric proteins of these two proteins we examined the tyrosine phosphorylation via the wild-type or mutant insulin receptors and evaluated their targeting to the plasma membrane by immunostaining the membrane ghost. Results: In contrast to IRS-1, IRS-3 was tyrosine-phosphorylated by the insulin receptor altering Tyr⁹⁶⁰ to Phe (Y960F), which disrupts the binding site of the PTB domain of IRSs, to an extent comparable to the wild-type receptor. The tyrosine phosphorylation of IRS-3 with the PH domain replacement via the Y960F insulin receptor markedly decreased, whereas that of IRS-3 with the PTB domain alteration was mildly impaired. Insulin-stimulated translocation of IRS-1 to the plasma membrane, as well as that of IRS-3 with the PH domain replacement, was wortmannin-sensitive, although that of IRS-3 was insulin-independent and wortmannin-resistant. Conclusions/interpretation: The affinity of the PH domain for the phospholipids in the plasma membrane seems to influence the receptor-substrate interaction required for IRS tyrosine phosphorylation, indicating that the PH domain and the PTB domain of IRSs cooperatively function in insulin-stimulated tyrosine phosphorylation of these proteins. [Diabetologia (2001) 44: 992–1004] Received: 17 October 2000 and in revised form: 27 March 2001     

甲状腺机能减退对仔鼠中枢神经系统Ⅱ型脱碘酶mRNA表达的影响

目的观察甲状腺激素机能减退(甲减)时仔鼠中枢神经系统Ⅱ型脱碘酶mRNA(D2-mRNA)的表达,研究甲状腺激素对脑发育调控的机制。方法怀孕Wistar雌鼠随机分为甲减组和对照组,从怀孕15d开始甲减组每日经胃灌注1%丙基硫氧嘧啶2.5ml,所生鼠即为甲减仔鼠。对照组每日经胃灌注生理盐水2.5ml。分别于出生时、出生后14、21和45d处死仔鼠,利用荧光定量PCR的方法,分析各组动物大脑皮质、小脑、脑干、海马及脊髓中D2的表达。结果甲减仔鼠大脑、脑干及脊髓中D2mRNA在出生时及出生后14d时表达量高于对照组,在21d和45d时与对照组无显著性差异;在小脑和海马中D2mRNA的表达量在出生时及出生后14、21d时都高于对照组,只有在45d时与对照组接近。结论甲减时仔鼠中枢神经系统D2表达增加,通过调节甲状腺激素水平对其生长发育起着重要作用。     

前咽缺陷蛋白-1在APP/PS1转基因阿尔茨海默病小鼠模型中枢神经系统的分布及表达

目的 研究y-分泌酶组件蛋白APH-1(anterior pharynx defective 1,APH-1)在成年APP/PS1双转基因痴呆小鼠中枢神经系统(central nervous system,CNS)中的分布及表达,以及在阿尔茨海默病(Alzheimer's disease,AD)模型鼠和野生型小鼠脑中的表达差异,以进一步明确APH-1与AD的关系.方法 对APP/PS1双转基因AD模型种鼠交配后产下的子代进行基因分型,用免疫组化方法检测APH-1在成年APP/PS1双转基因痴呆模型小鼠CNS内的分布及表达,以及比较APH-1在出生后1d、7d、21 d、120 d的痴呆小鼠及同窝野生型小鼠脑内的表达和分布情况.结果 APH-1广泛分布于成年痴呆小鼠CNS的各区域,包括大脑皮质、海马、嗅脑、丘脑、纹状体、尾状核、中缝大核、小脑、脑干和脊髓等;出生1 dAD模型鼠与同窝野生型小鼠大脑皮质内APH-1均有高水平表达,而出生7d、21d表达水平较低,且成年小鼠脑中其表达量有所回升;各时间点痴呆小鼠脑内APH-1免疫阳性反应都比同窝野生型小鼠显著增强(P＜0.05).结论 APH-1在痴呆小鼠的CNS中广泛分布,但不同脑区分布和表达存在差异;且痴呆小鼠和正常野生型小鼠脑内APH-1分布和表达有区别,这些差异可能与AD的发生相关.