L-Arginine (L-Arg), the precursor of nitric oxide (NO), plays an important role in muscle function. Fasttwitchglycolytic fibres are more susceptible to age-related atrophy than slow-twitch oxidative fibres.The effect ...L-Arginine (L-Arg), the precursor of nitric oxide (NO), plays an important role in muscle function. Fasttwitchglycolytic fibres are more susceptible to age-related atrophy than slow-twitch oxidative fibres.The effect of L-Arg/NO on protein metabolism of fast- and slow-twitch muscle fibres was evaluated inchickens. In Exp. 1, 48 chicks at 1 day old were divided into 4 groups of 12 birds and subjected to 4treatments: basal diet without supplementation or supplemented with 1% L-Arg, and water supplementedwith or without L-nitro-arginine methyl ester (L-NAME, 18.5 mM). In Exp. 2, 48 chicks weredivided into 4 groups of 12 birds fed with the basal diet and subjected to the following treatments: tapwater (control), tap water supplemented with L-NAME (18.5 mM), or molsidomine (MS, 0.1 mM), or18.5 mM L-NAME t 0.1 mM MS (NAMS). The regulatory effect of L-Arg/NO was further investigatedin vitro with myoblasts obtained from chicken embryo pectoralis major (PM) and biceps femoris (BF).In vivo, dietary L-Arg supplementation increased breast (t14.94%, P < 0.05) and thigh muscle mass(t23.40%, P < 0.05);whereas, MS treatment had no detectable influence. However, L-NAME treatmentblocked the beneficial influence of L-Arg on muscle development. L-Arg decreased (P < 0.05) proteinsynthesis rate, phosphorylated mTOR and ribosomal protein S6 kinase beta-1 (p70S6K) levels in breastmuscle, which was recovered by L-NAME treatment. In vitro, L-Arg or sodium nitroprusside (SNP)reduced protein synthesis rate, suppressed phosphorylated mTOR/p70S6K and decreased atrogin-1 andmuscle RING finger 1 (MuRF1) in myoblasts from PM muscle (P < 0.05). L-NAME abolished the inhibitoryeffect of L-Arg on protein synthesis and the mTOR/p70S6K pathway. However, myoblasts from BF muscleshowed the weak influence. Moreover, blocking the mTOR/p70S6K pathway with rapamycin suppressedprotein synthesis of the 2 types of myoblasts;whereas, the protein expression of atrogin-1 and MuRF1levels were restricted only in myoblasts from PM muscle. In conclusion, L-Arg/NO/mTOR/p70S6Kpathway enhances protein accumulation and muscle development in fast-twitch glycolytic muscle inchickens. L-Arg/NO regulates protein turnover in a muscle fibre specific way, which highlights the potentialclinical application in fast-twitch glycolytic muscle fibres.展开更多
目的：探讨哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin，mTOR）信号通路蛋白在卵巢型子宫内膜异位组织中的表达及其临床意义。方法：利用RT—PCR、蛋白质免疫印迹法、免疫组织化学法检测2011年1月～2013年6月就诊我院的卵...目的：探讨哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin，mTOR）信号通路蛋白在卵巢型子宫内膜异位组织中的表达及其临床意义。方法：利用RT—PCR、蛋白质免疫印迹法、免疫组织化学法检测2011年1月～2013年6月就诊我院的卵巢型子宫内膜异位症患者40例和正常增生期子宫内膜40例组织中mTOR及下游分子p70S6激酶（p70S6K）和4E—BP1的表达。结果：mTOR及下游分子p70S6K和4E—BP1在卵巢型子宫内膜异位组织中mRNA及蛋白的表达均低于正常子宫内膜组织。mTOR蛋白在卵巢型子宫内膜异位组织中为阳性表达，高于正常子宫内膜组织，且与痛经、月经异常、不孕无明显相关性，而与囊肿大小、异位内膜浸润深度及盆腔浸润情况关系显著。结论：mTOR信号通路与卵巢型子宫内膜异位症的发生、发展关系密切，mTOR蛋白失活可能是卵巢子宫内膜异位的显著标志，检测mTOR蛋白表达对卵巢子宫内膜异位的诊断具有一定意义。展开更多
基金the Key Technologies Research and Development Programof China(2021YFD1300405)the Earmarked Fund for China Agriculture Research System(CARS-40-K09)+1 种基金National Natural Science Foundation of China(31772619)Key Technology Research and Development Program of Shandong Province(2019JZZY020602).
文摘L-Arginine (L-Arg), the precursor of nitric oxide (NO), plays an important role in muscle function. Fasttwitchglycolytic fibres are more susceptible to age-related atrophy than slow-twitch oxidative fibres.The effect of L-Arg/NO on protein metabolism of fast- and slow-twitch muscle fibres was evaluated inchickens. In Exp. 1, 48 chicks at 1 day old were divided into 4 groups of 12 birds and subjected to 4treatments: basal diet without supplementation or supplemented with 1% L-Arg, and water supplementedwith or without L-nitro-arginine methyl ester (L-NAME, 18.5 mM). In Exp. 2, 48 chicks weredivided into 4 groups of 12 birds fed with the basal diet and subjected to the following treatments: tapwater (control), tap water supplemented with L-NAME (18.5 mM), or molsidomine (MS, 0.1 mM), or18.5 mM L-NAME t 0.1 mM MS (NAMS). The regulatory effect of L-Arg/NO was further investigatedin vitro with myoblasts obtained from chicken embryo pectoralis major (PM) and biceps femoris (BF).In vivo, dietary L-Arg supplementation increased breast (t14.94%, P < 0.05) and thigh muscle mass(t23.40%, P < 0.05);whereas, MS treatment had no detectable influence. However, L-NAME treatmentblocked the beneficial influence of L-Arg on muscle development. L-Arg decreased (P < 0.05) proteinsynthesis rate, phosphorylated mTOR and ribosomal protein S6 kinase beta-1 (p70S6K) levels in breastmuscle, which was recovered by L-NAME treatment. In vitro, L-Arg or sodium nitroprusside (SNP)reduced protein synthesis rate, suppressed phosphorylated mTOR/p70S6K and decreased atrogin-1 andmuscle RING finger 1 (MuRF1) in myoblasts from PM muscle (P < 0.05). L-NAME abolished the inhibitoryeffect of L-Arg on protein synthesis and the mTOR/p70S6K pathway. However, myoblasts from BF muscleshowed the weak influence. Moreover, blocking the mTOR/p70S6K pathway with rapamycin suppressedprotein synthesis of the 2 types of myoblasts;whereas, the protein expression of atrogin-1 and MuRF1levels were restricted only in myoblasts from PM muscle. In conclusion, L-Arg/NO/mTOR/p70S6Kpathway enhances protein accumulation and muscle development in fast-twitch glycolytic muscle inchickens. L-Arg/NO regulates protein turnover in a muscle fibre specific way, which highlights the potentialclinical application in fast-twitch glycolytic muscle fibres.
文摘目的探究干扰小RNA(si RNA)沉默小窝蛋白-1(CAV1)基因表达对人绒毛膜癌JEG-3细胞侵袭、迁移能力的影响及其可能的作用机制。方法将人绒毛膜癌JEG-3细胞分为对照组(不进行转染)、阴性组(转染si RNA-NC)和si RNA-CAV1组(转染si RNA-CAV1)。Transwell法检测下调CAV1表达对细胞侵袭、迁移能力的影响;实时定量PCR(q RT-PCR)检测转染细胞中CAV1 m RNA的表达水平;蛋白质印迹法(Western blot)检测细胞中CAV1、丝苏氨酸蛋白激酶(AKT)、雷帕霉素靶蛋白(MTOR)、核糖体p70S6激酶(p70S6K)、磷酸化AKT(p-AKT)、磷酸化MTOR(p-MTOR)、磷酸化p70S6K(p-p70S6K)蛋白的表达水平。结果 si RNA-CAV1组JEG-3细胞中CAV1 m RNA和蛋白的相对表达量均低于对照组(P﹤0.05);si RNA-CAV1组JEG-3细胞的侵袭数目、迁移数目均低于对照组(P﹤0.05);si RNA-CAV1组JEG-3细胞中AKT、MTOR、p70S6K以及磷酸化水平均低于对照组(P﹤0.05)。结论沉默CAV1表达可以抑制人绒毛膜癌JEG-3细胞的侵袭和迁移能力,该作用与AKT/MTOR/p70S6K信号通路有关。
文摘目的：探讨哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin，mTOR）信号通路蛋白在卵巢型子宫内膜异位组织中的表达及其临床意义。方法：利用RT—PCR、蛋白质免疫印迹法、免疫组织化学法检测2011年1月～2013年6月就诊我院的卵巢型子宫内膜异位症患者40例和正常增生期子宫内膜40例组织中mTOR及下游分子p70S6激酶（p70S6K）和4E—BP1的表达。结果：mTOR及下游分子p70S6K和4E—BP1在卵巢型子宫内膜异位组织中mRNA及蛋白的表达均低于正常子宫内膜组织。mTOR蛋白在卵巢型子宫内膜异位组织中为阳性表达，高于正常子宫内膜组织，且与痛经、月经异常、不孕无明显相关性，而与囊肿大小、异位内膜浸润深度及盆腔浸润情况关系显著。结论：mTOR信号通路与卵巢型子宫内膜异位症的发生、发展关系密切，mTOR蛋白失活可能是卵巢子宫内膜异位的显著标志，检测mTOR蛋白表达对卵巢子宫内膜异位的诊断具有一定意义。
