Age-related sarcopenia is a degenerative disease characterized by the decline in skeletal muscle mass and function during the aging process. Anabolic resistance, which refers to the diminished response of skeletal muscle to anabolic stimulation from leucine and other nutrients, is a significant contributing factor to its development. Recent studies have suggested that large neutral amino acid-transporter 1 (LAT1/SLC7A5) may play an important role in enhancing leucine's effects on protein synthesis in aging skeletal muscle. In this paper, the structure and function of LAT1 and its key molecules regulating aging skeletal muscle protein synthesis were reviewed, and the potential relationship between LAT1, as a transmembrane transporter of leucine, and protein synthesis in aging skeletal muscle was analyzed. The aim is to explore new mechanisms and insights for prevention and treatment of age-related sarcopenia, and provide reference for the application of relevant targets in clinical translational medicine.
Humans ; Leucine/metabolism* ; Muscle, Skeletal/metabolism* ; Aging/metabolism* ; Large Neutral Amino Acid-Transporter 1/metabolism* ; Protein Biosynthesis ; Sarcopenia/metabolism* ; Animals ; Muscle Proteins/biosynthesis*

The aim of the present study was to measure the kinetic parameters of skeletal muscle protein synthesis in rats by deuterated water (HO). Twenty Sprague-Dawley (SD) rats were labeled byHO through intraperitoneal injection and drinking. At the each end of the 1st, 3rd, 5th, 6th and 10th week after the firstHO labeling, four rats were sacrificed by cardiac puncture for blood plasma and quadriceps femoris sampling. Skeletal muscle protein and free amino acids in plasma were purified, hydrolyzed by hydrochloric acid and derived. The deuterium enrichments ofH-labeled alanyl in skeletal muscle protein and plasma protein-boundH-labeled alanine were determined by gas chromatography-mass spectrometry (GC-MS). The fractional synthesis rate of skeletal muscle protein and synthetic dynamic equation were calculated. The fractional synthetic rate of skeletal muscle protein was 12.8%/week, and synthetic dynamic equation was f= 0.158 × (1 - e). The results suggest that the kinetic parameters of skeletal muscle protein synthesis can be measured byHO labeling, and the method can be applied in long-term labeling experiment.
Alanine ; Amino Acids ; blood ; Animals ; Deuterium ; Gas Chromatography-Mass Spectrometry ; Kinetics ; Male ; Muscle Proteins ; biosynthesis ; Muscle, Skeletal ; metabolism ; Protein Biosynthesis ; Rats ; Rats, Sprague-Dawley ; Water

OBJECTIVETo observe the effect of Shenshuai Yingyang Capsule (SSYYJN) in ameliorating muscle atrophy in rats with chronic renal failure (CRF) and explore the role of Wnt7a-Akt/mTOR signal pathway in mediating this effect.

METHODSMale rats were randomly assigned to 5/6 nephrectomy group and sham-operated group, and the former group was further randomly divided into CRF model group, KA group, and SSYYJN group. The size of anterior tibia muscle was examined microscopically with HE staining. Protein synthesis in the soleus muscle was investigated by (14)C-phenylalanine experiment, and the expression of Wnt7a, frizzled-7, phospho-Akt, phospho-mTOR and GAPDH were detected with Western blotting.

RESULTSThe body weight, the wet and dry weight, cross-sectional area, and muscle protein synthesis of the anterior tibia muscles, and expressions of the proteins in the Wnt7a/Akt signaling pathway all increased significantly in SSYYJN and KA groups as compared with those in the model group.

CONCLUSIONSSYYJN can effectively improve muscle atrophy in the rat model of CRF possibly by reversing the reduction in the expressions of Wnt7a/Akt signaling pathway proteins in the skeletal muscles.

Animals ; Capsules ; Drugs, Chinese Herbal ; pharmacology ; Kidney Failure, Chronic ; complications ; Male ; Muscle Proteins ; biosynthesis ; Muscle, Skeletal ; drug effects ; Muscular Atrophy ; drug therapy ; Nephrectomy ; Proto-Oncogene Proteins ; metabolism ; Rats ; Signal Transduction ; TOR Serine-Threonine Kinases ; metabolism ; Wnt Proteins ; metabolism

PURPOSE: The purpose of this study was to examine the effects of Cu/Zn SOD on reduction of hindlimb muscular atrophy induced by cisplatin in rats. METHODS: Forty-two rats were assigned to three groups; control group, Cisplatin (CDDP) group and cisplatin with Cu/Zn SOD (CDDP-SOD) group. At day 35 hindlimb muscles were dissected. Food intake, activity, withdrawal threshold, muscle weight, and Type I, II fiber cross-sectional area (CSA) of dissected muscles were measured. Relative SOD activity and expression of MHC and phosphorylated Akt, ERK were measured after dissection. RESULTS: Muscle weight and Type I, II fiber CSA of hindlimb muscles in the CDDP group were significantly less than the control group. Muscle weight and Type I, II fiber CSA of hindlimb muscles, food intake, activity, and withdrawal thresholds of the CDDP-SOD group were significantly greater than the CDDP group. There were no significant differences in relative SOD activities of hindlimb muscles between the CDDP-SOD and CDDP groups. MHC expression and phosphorylated Akt, ERK of hindlimb muscles in the CDDP-SOD group were significantly greater than the CDDP group. CONCLUSION: Cu/Zn SOD attenuates hindlimb muscular atrophy induced by cisplatin through increased food intake and activity. Increment of phosphorylated Akt, ERK may relate to attenuation of hindlimb muscular atrophy.
Animals ; Body Weight/drug effects ; Cisplatin/*toxicity ; Disease Models, Animal ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Hindlimb ; Male ; Muscle, Skeletal/*drug effects/enzymology/metabolism ; Muscular Atrophy/*chemically induced/metabolism/pathology ; Phosphorylation ; Proto-Oncogene Proteins c-akt/metabolism ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins/biosynthesis/genetics/pharmacology ; Superoxide Dismutase/genetics/metabolism/pharmacology ; Superoxides/metabolism

OBJECTIVETo investigate effects of dahuang zhechong pill ( DHZCP) on the cell cycle and the related signal pathways in vascular smooth muscle cells (VSMCs) stimulated by platelet-derived growth factor (PDGF) with the method of serum pharmacology.

METHODSDNA synthesis in VSMCs was examined by detecting 5'-bromo-2'-deoxyuridine incorporation with the immunocytochemical method. The cycle of VSMCs was evaluated with flow cytometry. Expressions of cyclin D1, p27, protein kinase Cα (PKCα), and phosphorylated extracellular signal regulated kinase 1/2 (ERK1/2) were quantified by Western blot method.

RESULTSDHZCP containing serum significantly inhibited DNA synthesis of PDGF-stimulated VSMCs, arrested the cells in G G(1) phase, modulated the protein expressions of cyclin D D(1) and p27, and suppressed the activation of PKCα and ERK1/2.

CONCLUSIONDHZCP containing serum inhibits VSMCs proliferation via modulating the expressions of cell cycle proteins to arrest the cell in G G(1) phase, which is attributed to, at least in part, suppressing PKCα-ERK1/2 signaling in VSMCs.

Animals ; Aorta, Thoracic ; cytology ; Blood Proteins ; pharmacology ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; DNA ; biosynthesis ; Drugs, Chinese Herbal ; pharmacology ; G1 Phase ; drug effects ; physiology ; MAP Kinase Signaling System ; physiology ; Male ; Muscle, Smooth, Vascular ; cytology ; drug effects ; enzymology ; Platelet-Derived Growth Factor ; pharmacology ; Protein Kinase C-alpha ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the expression pattern of FHL2, which is an intracellular signaling transcription molecule during mineralization in cultured human periodontal ligament cells (hPDLCs) in vitro.

METHODShPDLCs were cultured in vitro. Test group was cultured with mineral induction media while control group without induction media. 0, 14, 28 days after culture, alizarin red staining was used to measure the mineral nodules formation. Immunocytochemistry was used to examine the expression of FHL2 protein 0 day and 14 days after mineral induction. Meanwhile, mRNA expression level of FHL2 was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) on the 0, 14, 28 days after induction.

RESULTS14 and 28 days after cultivation, mineral nodules formed and were stained positively with alizarin red staining in test group while no mineral nodule formed in control group. Immunocytochemical results indicated that hPDLCs in test group expressed FHL2 positively. According to RT-PCR results, 14 and 28 days after mineral induction, the expression levels of FHL2 both increased significantly when compared with 0 day (P<0.01), and the expression level at 14 days was 1.4 folds of 0 day.

CONCLUSIONFHL2 protein is found to be involved in the in vitro mineralization of hPDLCs. FHL2 protein may play a role in the differentiation and mineralization of hPDLCs.

Cell Differentiation ; Cells, Cultured ; Humans ; In Vitro Techniques ; LIM-Homeodomain Proteins ; biosynthesis ; Muscle Proteins ; biosynthesis ; Periodontal Ligament ; RNA, Messenger ; Transcription Factors ; biosynthesis

OBJECTIVETo construct the recombinant plasmid pcDNA3.0-RGC32 and evaluate the effect of the response gene to complement-32 (RGC32) on cell cytoskeleton in vitro.

METHODSThe full-length cDNA of RGC32 was obtained by RT-PCR and inserted into the eukaryotic expression vector pcDNA3.0 to generate the recombinant plasmid pcDNA3.0-RGC32. After transfection of the recombinant plasmid into SW480 cells, the expression of RGC32 in the cells was detected by Western blotting. The cytoskeleton of SW480 cells was visualized before and after the transfection, and the changes in the cell migration ability was assessed by wound-healing assay.

RESULTSThe recombinant plasmid pcDNA3.0-RGC32 was successfully constructed. The expression of RGC32 was significantly increased in SW480 cells after transfection with pcDNA3.0-RGC32. Before the transfection, the microfilaments of SW480 cells were few and short without obvious polarity, but after the transfection, the microfilaments were increased and elongated with also an obvious polarity, and the invasive structures of lamellae and lamellipodia occurred. The migration ability of the cells was enhanced after transfection with pcDNA3.0-RGC32.

CONCLUSIONOverexpression of RGC32 can cause the reorganization of cytoskeleton and promotes the cell migration, which can be an important mechanism of RGC32 in promoting cancer metastasis.

Cell Cycle Proteins ; biosynthesis ; genetics ; Cell Line, Tumor ; Cell Movement ; Colorectal Neoplasms ; genetics ; metabolism ; pathology ; Cytoskeleton ; chemistry ; metabolism ; Genetic Vectors ; Humans ; Muscle Proteins ; biosynthesis ; genetics ; Neoplasm Metastasis ; genetics ; Nerve Tissue Proteins ; biosynthesis ; genetics ; Plasmids ; genetics ; Recombinant Proteins ; biosynthesis ; genetics

The influence of spinal cord injury (SCI) on protein expression in the rat urinary bladder was assessed by proteomic analysis at different time intervals post-injury. After contusion SCI between T9 and T10, bladder tissues were processed by 2-DE and MALDI-TOF/MS at 6 hr to 28 days after SCI to identify proteins involved in the healing process of SCI-induced neurogenic bladder. Approximately 1,000 spots from the bladder of SCI and sham groups were visualized and identified. At one day after SCI, the expression levels of three protein were increased, and seven spots were down-regulated, including heat shock protein 27 (Hsp27) and heat shock protein 20 (Hsp20). Fifteen spots such as S100-A11 were differentially expressed seven days post-injury, and seven proteins including transgelin had altered expression patterns 28 days after injury. Of the proteins with altered expression levels, transgelin, S100-A11, Hsp27 and Hsp20 were continuously and variably expressed throughout the entire post-SCI recovery of the bladder. The identified proteins at each time point belong to eight functional categories. The altered expression patterns identified by 2-DE of transgelin and S100-A11 were verified by Western blot. Transgelin and protein S100-A11 may be candidates for protein biomarkers in the bladder healing process after SCI.
Animals ; Biological Markers/metabolism ; Electrophoresis, Gel, Two-Dimensional ; Female ; HSP20 Heat-Shock Proteins/metabolism ; HSP27 Heat-Shock Proteins/metabolism ; Microfilament Proteins/metabolism ; Muscle Proteins/metabolism ; Proteome/*biosynthesis ; Proteomics ; Rats ; Rats, Sprague-Dawley ; S100 Proteins/metabolism ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Spinal Cord Injuries/*metabolism/pathology ; Urinary Bladder/*metabolism ; *Wound Healing

The experiment was designed to investigate the function of SREBP cleavage-activating protein (SCAP) mutant (D443N) by constructing an eukaryotic expressive vector using a smooth muscle specific promoter SM22 (pGL3-SM22-SCAP(D443N)). SM22 promoter (pSM22) was amplified from genome DNA of mice by nested PCR, and then cloned into pMD-T vector. The SM22 promoter fragment released from the vector by Kpn I and Hind III digestion was sub-cloned into pGL3-control-Luc vector, to form pGL3-SM22-Luc. The activity of pSM22 in human vascular smooth muscle cells (VSMCs) was tested using Dual-Luciferase Reporter System. SCAP(D443) mutant amplified from plasmid pTK-HSV-SCAP(D443N) and pSM22 from mice liver were cloned into pGL3-control vector to construct pGL3-SM22-SCAP(D443N) which was transfected into Chinese hamster ovary cells (CHO) to test SCAP(D443) expression by real-time PCR and Western blot. The sequence and construction of pGL3-SM22-SCAP(D443N) were correct. SM22 promoter activity initiated the expression of luciferase in VSMCs and also drove SCAP(D443) expression in transfected CHO cells. The pGL3-SM22-SCAP(D443N) eukaryotic expression vector was successfully constructed and the recombinant vector provides a powerful approach in investigating the function and regulation of SCAP and also in producing vascular smooth muscle specific SCAP transgenic mice.
Animals ; CHO Cells ; Cricetinae ; Cricetulus ; Genetic Vectors ; genetics ; Humans ; Intracellular Signaling Peptides and Proteins ; genetics ; physiology ; Membrane Proteins ; biosynthesis ; genetics ; physiology ; Mice ; Mice, Transgenic ; Microfilament Proteins ; genetics ; Muscle Proteins ; genetics ; Mutant Proteins ; biosynthesis ; genetics ; Promoter Regions, Genetic ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Transfection

In order to study ovine follistatin function, we amplified the total of 1038 base pair of ovine complete follistatin cDNA and cloned into pGEM-T vector by RT-PCR from ovine ovary RNA. After removal of the signal peptide it was subcloned into the pET41a to construct the prokaryotic expression vector, named pFSsig-. SDS-PAGE and Western blotting identified the 66 kDa product of the expression of follistatin cDNA. Based on the complete CDS sequence, we cloned follistatin N-terminal domain and domain 1 with PCR and inserted into pLEX-MCS lentiviral vector, named pFS-N+D1. After package and passage of lentivirus in 293T cells, and then infected sheep primary muscle cells (SPMC). The expression of FS N+D1 in SPMC was assayed by Western blotting. The cell growth curve of the infected SPMC and noninfected control cells displayed that FS N+D1 stablly transfected SPMC proliferated significantly faster than the control cells (P < 0.01). Our data inferred that ovine FS N+D1 domain had the function to stimulate sheep muscle cell growth.
Animals ; Cells, Cultured ; Escherichia coli ; genetics ; metabolism ; Female ; Follistatin ; biosynthesis ; genetics ; Genetic Vectors ; genetics ; Lentivirus ; genetics ; metabolism ; Muscle, Skeletal ; cytology ; Ovary ; metabolism ; Prokaryotic Cells ; metabolism ; Protein Structure, Tertiary ; Recombinant Proteins ; biosynthesis ; genetics ; Sheep