猪骨骼肌快肌肌钙蛋白C2基因的cDNA克隆与表达分析

从人骨骼肌快肌肌钙蛋白C2（TNNC2）基因出发,在dbEST数据库中进行同源性搜索,找到一个有较高同源性且在猪背最长肌中表达EST（BM083186）。通过电子克隆和进一步RT-PCR实验验证,获得猪TNNC2基因全长cDNA序列,其全长843bp,开放阅读框为201～683bp,编码有160个氨基酸。同源性分析结果表明,与人、鼠的骨骼肌快肌肌钙蛋白C2基因cDNA编码区（CDS）同源性分别为93.6％、90.5％,蛋白序列同源性均为97.5%。多种组织的半定量RT-PCR研究表明,该基因在骨骼肌中表达,并且在杜洛克猪背最长肌中的表达比兰塘猪高。     

ACTN3 GENOTYPE IS ASSOCIATED WITH TESTOSTERONE LEVELS OF ATHLETES

α-Actinin-3 (ACTN3) has been proposed to regulate skeletal muscle differentiation and hypertrophy through its interaction with the signalling protein calcineurin. Since the inhibition of calcineurin potentiates the production of testosterone, we hypothesized that α-actinin-3 deficiency (predicted from the ACTN3 XX genotype) may influence serum levels of testosterone of athletes. Objective: To investigate the association of ACTN3 gene R577X polymorphism with resting testosterone levels in athletes. Methods: A total of 209 elite Russian athletes from different sports (119 males, 90 females) were genotyped for ACTN3 gene R577X polymorphism by real-time PCR. Resting testosterone was examined in serum of athletes using enzyme immunoassay. Results: The mean testosterone levels were significantly higher in both males and females with the ACTN3 R allele than in XX homozygotes (males: RR: 24.9 (5.7), RX: 21.8 (5.5), XX: 18.6 (4.9) ng · mL^-1, P = 0.0071; females: RR: 1.43 (0.6), RX: 1.21 (0.71), XX: 0.79 (0.66) ng · mL^-1, P = 0.0167). Conclusions: We found that the ACTN3 R allele was associated with high levels of testosterone in athletes, and this may explain, in part, the association between the ACTN3 RR genotype, skeletal muscle hypertrophy and power athlete status.     

The evolution of skeletal muscle performance: gene duplication and divergence of human sarcomeric α‐actinins

In humans, there are two skeletal muscle α‐actinins, encoded by ACTN2 and ACTN3, and the ACTN3 genotype is associated with human athletic performance. Remarkably, approximately 1 billion people worldwide are deficient in α‐actinin‐3 due to the common ACTN3 R577X polymorphism. The α‐actinins are an ancient family of actin‐binding proteins with structural, signalling and metabolic functions. The skeletal muscle α‐actinins diverged ～250–300 million years ago, and ACTN3 has since developed restricted expression in fast muscle fibres. Despite ACTN2 and ACTN3 retaining considerable sequence similarity, it is likely that following duplication there was a divergence in function explaining why α‐actinin‐2 cannot completely compensate for the absence of α‐actinin‐3. This paper focuses on the role of skeletal muscle α‐actinins, and how possible changes in functions between these duplicates fit in the context of gene duplication paradigms.     

The JAK2/STAT3 Signal Pathway Regulates the Expression of Genes Related to Skeletal Muscle Development and Energy Metabolism in Mice and Mouse Skeletal Muscle Cells

The gene encoding a β-galactosidase from Entevobacter cloacae GAO was cloned and expressed in Escherichia coli. The nucleotide sequence of the insert of a positive clone had an open reading frame of 3084 bp that encoded a polypeptide of 1028 amino acid residues with a calculated molecular mass of 116,677 daltons. The amino acid sequence of β-galactosidase deduced from the nucleotide sequence, especially the sequence around the putative active site and of the fourteen regions, showed significant homology to β-galactosidases of other microorganisms, E. coli, Klebsiella pneumoniae, Lactobacillus bulgaricus, and Clostridium acetobutylicum.     

TRB3基因敲除减轻糖尿病小鼠中骨骼肌萎缩和纤维化的研究

摘要 目的：探讨TRB3基因敲除对糖尿病小鼠中骨骼肌萎缩和纤维化的影响。方法：选择30只TRB3敲除（TRB3-/-）小鼠和30只C57/BL6J小鼠,随机分为4组,包括TRB3基因敲除糖尿病模型组（A组）、TRB3基因敲除正常对照组（B组）、普通对照组（C组）和糖尿病模型组（D组）。正常对照组小鼠喂养标准大鼠饲料,糖尿病模型小鼠使用腹腔注射小剂量链脲佐菌素的方法建立糖尿病小鼠模型。进行前肢握力测试、悬栅试验、肌肉功能试验,同时测定骨微结构各指标水平、抗I型胶原蛋白和抗III型胶原蛋白水平、萎缩基因MuRF1和Atrogin-1水平。结果：A组、B组、D组小鼠前肢握力显著低于C组,其中D组小鼠前肢握力最低（P<0.05）;A组、B组、D组小鼠悬栅试验倒挂时间显著低于C组,其中D组小鼠悬栅试验倒挂时间最短（P<0.05）;A组、B组、D组小鼠肌肉功能CSA值显著低于C组,其中D组小鼠肌肉功能CSA值最低（P<0.05）;A组、B组、D组小鼠骨微结构指标BMD、BV/TV、Tb.N、Tb.Th值显著小于C组,其中D组数值最低（P<0.05）;而Tb.Sp和SMI值显著大于C组,其中D组数值最高（P<0.05）;A组、B组、D组小鼠抗I型胶原蛋白和抗III型胶原蛋白水平显著高于C组,其中D组抗I型胶原蛋白和抗III型胶原蛋白水平最高（P<0.05）;A组、B组、D组小鼠萎缩基因MuRF1和Atrogin-1水平显著高于C组,其中D组萎缩基因MuRF1和Atrogin-1水平最高（P<0.05）。结论：TRB3基因敲除可显著减轻糖尿病小鼠中骨骼肌萎缩和纤维化,增加骨强度。     

人骨骼肌M蛋白的提取与纯化

依据Ｔｒｉｎｉｃｋ－Ｅｐｐｅｎｂｅｒｇｅｒ对鸡骨骼肌Ｍ蛋白的提取方法,由人骨骼肌中得到的Ｍ蛋白粗提物除含分子量为１６５０００的Ｍ蛋白外,还含有分子量为１８５０００和１４００００（Ｃ成分）的两组分。由于在粗提物中未发现分子量为９００００的磷酸化酶,我们将最终纯化步骤中的亲和层析改为制备电泳,同样获得了纯化的Ｍ蛋白。     

基因芯片在骨骼肌老龄化相关基因表达谱中的应用

对老龄组大鼠 (30月龄 )和年轻对照组大鼠 (3月龄 )的腓肠肌超微结构进行观察 ,可以看到前者肌肉肌纤维萎缩伴有线粒体空泡变性。并进行总RNA抽提、mRNA纯化、探针制备 ,应用基因芯片筛选老龄化相关基因 ,两组大鼠骨骼肌重复出现的差异表达基因 12 7个 ,下调基因涉及能量代谢、信号转导 ,上调基因涉及蛋白质分解、细胞凋亡     

肥胖诱导的骨骼肌萎缩机制研究进展

骨骼肌是人体氨基酸和蛋白质的主要贮存、代谢库,其正常功能和代谢过程受到多种病理因素的影响。骨骼肌萎缩发生于骨骼肌稳态严重失衡状态下,对患者生活和社会医疗造成了沉重负担。近年来,由于世界肥胖人群数量激增,肥胖诱导的骨骼肌萎缩正日益成为公共卫生的严峻挑战之一。肥胖诱导的骨骼肌萎缩过程涉及多种信号分子或通路的改变,如泛素蛋白酶系统、自噬溶酶体系统、胰岛素/IGF1-PI3K-Akt、肌肉生长抑制素、白细胞介素-6、肿瘤坏死因子等;这些信号分子或通路在肥胖状态下被激活或抑制后,可共同影响蛋白质合成/分解平衡进而造成骨骼肌萎缩。基于上述信号分子或通路,系统总结并讨论了肥胖诱导的骨骼肌萎缩机制,以期为寻找缓解/治疗肥胖诱导的肌萎缩靶点和进一步开发利用天然植物化学物提供理论依据。     

小鼠骨骼肌纤维类型定量PCR内参基因的筛选

旨在筛选定量PCR检测不同骨骼肌纤维类型的稳定内参基因,为骨骼肌的能量和糖代谢等功能研究提供基础数据.试验选用6周龄小鼠,采集腓肠肌(Gastrocnemius muscle,GAS)、比目鱼肌(Soleus,SOL)、胫骨前肌(Tibialis anterior muscle,TA)和趾长伸肌(Extensor di...     

microRNAs对动物骨骼肌细胞增殖分化的调控作用

microRNAs（miRNAs）是一种含有约22个核苷长度的非编码RNA,在基因表达调控中发挥重要作用.近年研究表明,miRNAs在细胞增殖、分化和凋亡过程中扮演重要角色.miRNAs在骨骼肌中表达,是肌肉发育和功能必需的.本文综述了miRNAs的生物生成和作用机制,miRNAs调节骨骼肌细胞增殖分化及肌纤维类型的最新研究进展.     

Quantitative 3D Mapping of the Human Skeletal Muscle Mitochondrial Network

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EGF、bFGF和PHGF对大鼠骨骼肌卫星细胞增殖的影响

用MTT、流式细胞技术、溴脱氧核甘尿嘧啶(bromodeoxyuridine,BrdU)掺入法及免疫细胞化学检测增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)的方法探讨了表皮生长因子(epidermal growth factor,EGF)、碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)及促肝细胞生长因子(hepatocyte growth-promoting factor,PHGF)对大鼠骨骼肌卫星细胞增殖的影响。结果表明bFGF、PHGF对骨骼肌卫星细胞有较强的促增殖作用,且两者之间无差别,bFGF最佳作用浓度为5μg／L,PHGF最佳作用浓度为10μg／ml。与其他生长因子相比,PHGF价格低廉易于获取,适宜推广。EGF增殖作用不明显。     

PAX3 Confers Functional Heterogeneity in Skeletal Muscle Stem Cell Responses to Environmental Stress

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失神经骨骼肌萎缩的研究现状及进展

当今骨科领域,周围神经损伤一直影响着患者疗效。肌萎缩的发生,细胞凋亡导致骨骼肌萎缩,神经-肌肉接头处营养因子的代谢发生障碍,肌卫星细胞的减少,生长因子以及线粒体和各种酶的变化都是失神经骨骼肌萎缩的机制。电刺激法,保护神经元,生长因子,神经植入提高神经再生速度以及被动活动可以有效治疗患者。失神经骨骼肌萎缩的研究进展也趋于完善。     

从骨骼肌可塑性透视运动适应的细胞机制

作为一种高度可塑的组织,骨骼肌能应对运动刺激产生适应性变化,且适量的运动对预防心血管疾病、糖尿病和癌症有一定的干预作用。然而在运动生理学界,有关哪种运动方式对健康促进更有效的争辩由来已久,且其内在机制不完全明确。在本文中,笔者将比较不同类型运动介导运动适应的信号通路,并大胆推测其根本异同点,在丰富运动适应理论构架的同时对民众提出相关指导性意见。     

The ACTN3 R577X variant in sprint and strength performance

[Purpose]

The aim of this study is to examine the association between the distribution of ACTN3 genotypes and alleles in power, speed, and strength-oriented athletics.

[Methods]

ACTN3 genotyping was carried out for a total of 975 Korean participants: top-level sprinters (n = 58), top-level strength athletes (n = 63), and healthy controls (n = 854).

[Results]

Genetic associations were evaluated by chi-squire test or Fisher’s exact test. In the power-oriented group composed of sprinters and strength athletes, the frequency of the XX genotype was significantly underrepresented (11.6%) in comparison to its representation in the control group (11.6% versus 19.1%, P < 0.05). When the power-oriented group was divided into strength-oriented and speed-oriented groups, no significant difference in the ACTN3 XX genotype was found between the strength-oriented athletes and the controls (15.9% versus 19.1%, P < 0.262). Only the speed-oriented athletes showed significant differences in the frequency distributions of the ACTN3 XX genotype (6.9% versus 19.1%, P < 0.05) from that of the controls.

[Conclusion]

The ACTN3 genotype seems to mainly affect sports performance and especially speed.     

Metabolic Maturation during Muscle Stem Cell Differentiation Is Achieved by miR-1/133a-Mediated Inhibition of the Dlk1-Dio3 Mega Gene Cluster

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骨骼肌中肌浆网/内质网钙ATP酶的功能及其作用机制

骨骼肌是机体生命活动和能量代谢的重要场所,其代谢紊乱会诱发一系列肌肉疾病。Ca²⁺作为肌肉收缩过程的重要调节器,在骨骼肌的功能行使中发挥重要作用。骨骼肌细胞中Ca²⁺浓度主要受肌浆网/内质网钙ATP酶(sarcoplasmic/endoplasmic reticulum Ca²⁺ATPase, SERCA)的调节。SERCA利用ATP水解产生的能量介导胞质Ca²⁺进入肌浆网内腔,维持胞质Ca²⁺平衡。SERCA功能的失调会引发一系列骨骼肌疾病,而SERCA活性受部分肌浆网蛋白质的调控,跨膜蛋白质PLN、SLN、MRLN、DWORF和sAnk1以及胞质蛋白质THADA和SAR,其通过磷酸化,进而调控SERCA的功能。本文对骨骼肌中SERCA的功能、调控SERCA的相关功能蛋白质的结构及其作用机制进行了总结,以期为骨骼肌相关疾病的治疗提供最新的思路和方法。     

不同病因肝硬化患者L3骨骼肌指数特征及其对患者营养状况的预测价值分析

摘要 目的：探讨不同病因肝硬化患者L3骨骼肌指数特征及其对患者营养状况的预测价值分析。方法：选取2019年6月-2022年6月在我院收治的120例肝硬化患者作为研究对象,其中乙肝肝硬化40例,酒精性肝硬化40例,自身免疫性肝炎肝硬化40例。比较乙肝肝硬化组,酒精性肝硬化组,自身免疫性肝炎肝硬化L3 SMI的特征。采用Pearson相关检验分析L3 SMI与肝硬化患者营养状况的相关性。采用Logistics回归模型构建影响肝硬化营养状况的独立危险因素。采用受试者工作曲线（ROC）评估L3 SMI对肝硬化营养状况的预测价值。结果：自身免疫性肝炎肝硬化组L3 SMI、25（OH）D、ALB、PA、TRF的表达水平均显著低于酒精性肝硬化组和乙肝肝硬化组（P<0.05）,且酒精性肝硬化组显著低于乙肝肝硬化组（P<0.05）。肝硬化患者LSM与25（OH）D、ALB、PA、TRF均显著正相关（P<0.05）。以肝硬化患者营养状况作为因变量（营养正常=0,营养不良=1）纳入logistics回归模型,结果显示,25（OH）DALB、PA、TRF、L3 SMI是危险因素（P<0.05）。多因素分析结果显示,25（OH）DALB、PA、TRF、L3 SMI是影响肝硬化患者营养状况的独立危险因素（P<0.05）。L3 SMI预测评估肝硬化患者营养状况的Youden指数0.765,敏感度85.00（%）,特异度82.00（%）,AUC值0.810,95%CI：0.685~0.912。结论：不同病因肝硬化患者L3 SMI存在明显差异,临床可采用L3 SMI对肝硬化患者营养状况做出预测评估。