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Muroya Y, Ito O. Effect of clofibrate on fatty acid metabolism in the kidney of puromycin-induced nephrotic rats. Clin Exp Nephrol 2016; 20:862-870. [PMID: 26949064 DOI: 10.1007/s10157-016-1253-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 02/24/2016] [Indexed: 11/25/2022]
Abstract
BACKGROUND Proteinuria plays an essential role in the progression of tubulointerstitial damage, which causes end-stage renal disease. An increased load of fatty acids bound to albumin reabsorbed into proximal tubular epithelial cells (PTECs) contributes to tubulointerstitial damage. Fibrates, agonists of peroxisome proliferator-activated receptor α (PPARα), have renoprotective effects against proteinuria whereas the effects of these compounds on fatty acid metabolism in the kidney are still unknown. Therefore, the present study examined whether the renoprotective effects of clofibrate were associated with improvement of fatty acid metabolism in puromycin aminonucleoside (PAN)-induced nephrotic rats. METHODS Rats were allocated to the control, PAN or clofibrate-treated PAN group. Biochemical parameters, renal injury and changes in fatty acid metabolism were studied on day14. RESULTS PAN increased proteinuria, lipid accumulation in PTECs, excretions of N-acetyl-β-D-glucosaminidase (NAG) and 8-hydroxydeoxyguanosine (8OHdG) and the area of caspase 3-positive tubular cells. It decreased renal expressions of medium-chain acyl-CoA dehydrogenase (MCAD), cytochrome P450 (CYP)4A, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) and estrogen-related receptor α (ERRα) without change of the expression of PPARα. Clofibrate reduced proteinuria, lipid accumulation, NAG excretion and the area of caspase 3-positive tubular cells. However, albumin excretion was not reduced and 8OHdG excretion was increased. Clofibrate minimized changes in MCAD, CYP4A, PGC-1α and ERRα expressions with increased PPARα, very long-chain acyl-CoA dehydrogenase (VLCAD) and long-chain acyl-CoA dehydrogenase (LCAD) expressions. CONCLUSION Clofibrate is protective against renal lipotoxicity in PAN nephrosis. This study indicates that clofibrate has renoprotective effects through maintaining fatty acid metabolism in the kidney of PAN-induced nephrotic rats.
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Affiliation(s)
- Yoshikazu Muroya
- Department of General Medicine and Rehabilitation, Tohoku Medical and Pharmaceutical University School of Medicine, 1-12-1 Fukumuro, Miyagino-ku, Sendai, 983-8512, Japan.
| | - Osamu Ito
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Sendai, Japan
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Leucine-induced anabolic-catabolism: two sides of the same coin. Amino Acids 2015; 48:321-36. [DOI: 10.1007/s00726-015-2109-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 09/28/2015] [Indexed: 10/22/2022]
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Zizola C, Kennel PJ, Akashi H, Ji R, Castillero E, George I, Homma S, Schulze PC. Activation of PPARδ signaling improves skeletal muscle oxidative metabolism and endurance function in an animal model of ischemic left ventricular dysfunction. Am J Physiol Heart Circ Physiol 2015; 308:H1078-85. [PMID: 25713305 DOI: 10.1152/ajpheart.00679.2014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 02/18/2015] [Indexed: 01/06/2023]
Abstract
Exercise intolerance in heart failure has been linked to impaired skeletal muscle oxidative capacity. Oxidative metabolism and exercise capacity are regulated by PPARδ signaling. We hypothesized that PPARδ stimulation reverts skeletal muscle oxidative dysfunction. Myocardial infarction (MI) was induced in C57BL/6 mice and the development of ventricular dysfunction was monitored over 8 wk. Mice were randomized to the PPARδ agonist GW501516 (5 mg/kg body wt per day for 4 wk) or placebo 8 wk post-MI. Muscle function was assessed through running tests and grip strength measurements. In muscle, we analyzed muscle fiber cross-sectional area and fiber types, metabolic gene expression, fatty acid (FA) oxidation and ATP content. Signaling pathways were studied in C2C12 myotubes. FA oxidation and ATP levels decreased in muscle from MI mice compared with sham- operated mice. GW501516 administration increased oleic acid oxidation levels in skeletal muscle of the treated MI group compared with placebo treatment. This was accompanied by transcriptional changes including increased CPT1 expression. Further, the PPARδ-agonist improved running endurance compared with placebo. Cell culture experiments revealed protective effects of GW501516 against the cytokine-induced decrease of FA oxidation and changes in metabolic gene expression. Skeletal muscle dysfunction in HF is associated with impaired PPARδ signaling and treatment with the PPARδ agonist GW501516 corrects oxidative capacity and FA metabolism and improves exercise capacity in mice with LV dysfunction. Pharmacological activation of PPARδ signaling could be an attractive therapeutic intervention to counteract the progressive skeletal muscle dysfunction in HF.
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Affiliation(s)
- Cynthia Zizola
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York, New York; and
| | - Peter J Kennel
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York, New York; and
| | - Hirokazu Akashi
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York, New York; and
| | - Ruiping Ji
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York, New York; and
| | - Estibaliz Castillero
- Division of Cardiothoracic Surgery, Columbia University Medical Center, New York, New York
| | - Isaac George
- Division of Cardiothoracic Surgery, Columbia University Medical Center, New York, New York
| | - Shunichi Homma
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York, New York; and
| | - P Christian Schulze
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York, New York; and
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Takeda T, Tsuiji K, Li B, Tadakawa M, Yaegashi N. Proliferative effect of Hachimijiogan, a Japanese herbal medicine, in C2C12 skeletal muscle cells. Clin Interv Aging 2015; 10:445-51. [PMID: 25709418 PMCID: PMC4330035 DOI: 10.2147/cia.s75945] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Background Hachimijiogan (HJG), Ba-Wei-Di-Huang-Wan in Chinese, is one of the most popular herbal medicines in Japanese Kampo. HJG is often prescribed for the prevention and treatment of age-related diseases. Muscle atrophy plays an important role in aging-related disabilities such as sarcopenia. The purpose of this study was to investigate the possible beneficial effect of HJG on skeletal muscle. Methods Cells of murine skeletal muscle myoblast cell line C2C12 were used as an in vitro model of muscle cell proliferation and differentiation. The effect of HJG on C2C12 cell proliferation and differentiation was assessed. We counted the number of myotubes morphologically to assess the degree of differentiation. Results HJG treatment (200 μg/mL) for 3 days significantly increased C2C12 cell number by 1.23-fold compared with that of the control. HJG promoted the proliferation of C2C12 cells through activation of the ERK1/2 signaling pathway without affecting the Akt signaling pathway. HJG did not affect the differentiation of C2C12 cells. Conclusion HJG had beneficial effects on skeletal muscle myoblast proliferation. These findings may provide a useful intervention for the prevention and treatment of sarcopenia.
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Affiliation(s)
- Takashi Takeda
- Division of Women's Health, Research Institute of Traditional Asian Medicine, Kinki University School of Medicine, Osaka, Japan ; Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kenji Tsuiji
- Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Bin Li
- Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Mari Tadakawa
- Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Nobuo Yaegashi
- Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Sendai, Japan
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Suryawan A, Nguyen HV, Almonaci RD, Davis TA. Differential regulation of protein synthesis in skeletal muscle and liver of neonatal pigs by leucine through an mTORC1-dependent pathway. J Anim Sci Biotechnol 2014; 3. [PMID: 22675606 PMCID: PMC3366465 DOI: 10.1186/2049-1891-3-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Neonatal growth is characterized by a high protein synthesis rate that is largely due to an enhanced sensitivity to the postprandial rise in insulin and amino acids, especially leucine. The mechanism of leucine's action in vivo is not well understood. In this study, we investigated the effect of leucine infusion on protein synthesis in skeletal muscle and liver of neonatal pigs. To evaluate the mode of action of leucine, we used rapamycin, an inhibitor of mammalian target of rapamycin (mTOR) complex-1 (mTORC1). Overnight-fasted 7-day-old piglets were treated with rapamycin for 1 hour and then infused with leucine (400 μmol·kg(-1)·h(-1)) for 1 hour. Leucine infusion increased the rate of protein synthesis, and ribosomal protein S6 kinase 1 (S6K1) and eukaryotic initiation factor (eIF) 4E-binding protein-1 (4E-BP1) phosphorylation in gastrocnemius and masseter muscles (P < 0.05), but not in the liver. The leucine-induced stimulation of protein synthesis and S6K1 and 4E-BP1 phosphorylation were completely blocked by rapamycin, suggesting that leucine action is by an mTORC1-dependent mechanism. Neither leucine nor rapamycin had any effect on the activation of the upstream mTORC1 regulators, AMP-activated protein kinase and protein kinase B, in skeletal muscle or liver. The activation of eIF2α and elongation factor 2 was not affected by leucine or rapamycin, indicating that these two pathways are not limiting steps of leucine-induced protein synthesis. These results suggest that leucine stimulates muscle protein synthesis in neonatal pigs by inducing the activation of mTORC1 and its downstream pathway leading to mRNA translation.
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Affiliation(s)
- Agus Suryawan
- Department of Pediatrics, Baylor College of Medicine, United States, Department of Agriculture/Agriculture Research Service Children's Nutrition Research Center, 1100 Bates Street, Houston, TX 77030, USA
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Suryawan A, Torrazza RM, Gazzaneo MC, Orellana RA, Fiorotto ML, El-Kadi SW, Srivastava N, Nguyen HV, Davis TA. Enteral leucine supplementation increases protein synthesis in skeletal and cardiac muscles and visceral tissues of neonatal pigs through mTORC1-dependent pathways. Pediatr Res 2012; 71:324-31. [PMID: 22391631 PMCID: PMC3619200 DOI: 10.1038/pr.2011.79] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
INTRODUCTION Leucine (Leu) activates mammalian target of rapamycin (mTOR) to upregulate protein synthesis (PS). RESULTS PS in skeletal muscles, heart, liver, pancreas, and jejunum, but not kidney, were greater in low protein supplemented with Leu (LP+L) than LP, but lower than high protein (HP). In longissimus dorsi muscle, protein kinase B phosphorylation was similar in LP and LP+L, but lower than HP. Although less than HP, p70 ribosomal S6 kinase 1 (S6K1) and eukaryotic initiation factor (eIF) 4E binding protein 1 (4EBP1) association with regulatory associated protein of mammalian target of rapamycin was greater in LP+L than LP, resulting in higher S6K1 and 4EBP1 phosphorylation. Feeding LP+L vs. LP decreased 4EBP1·eIF4E and increased eIF4E·eIF4G formation, but not to HP. Similar results were obtained for S6K1 and 4EBP1 phosphorylation in gastrocnemius, masseter, heart, liver, pancreas, and jejunum, but not kidney. eIF2α and elongation factor 2 phosphorylation was unaffected by treatment. DICUSSION: Our results suggest that enteral Leu supplementation of a low protein diet enhances PS in most tissues through mTOR complex 1 pathways. METHODS To examine enteral Leu effects on PS and signaling activation, 5-d-old piglets were fed for 24 h diets containing: (i) LP, (ii) LP+L, or (iii) HP.
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Affiliation(s)
- Agus Suryawan
- Department of Pediatrics, United States Department of Agriculture/Agriculture Research Service Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
| | - Roberto Murgas Torrazza
- Department of Pediatrics, United States Department of Agriculture/Agriculture Research Service Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
| | - Maria C. Gazzaneo
- Department of Pediatrics, United States Department of Agriculture/Agriculture Research Service Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
| | - Renán A. Orellana
- Department of Pediatrics, United States Department of Agriculture/Agriculture Research Service Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
| | - Marta L. Fiorotto
- Department of Pediatrics, United States Department of Agriculture/Agriculture Research Service Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
| | - Samer W. El-Kadi
- Department of Pediatrics, United States Department of Agriculture/Agriculture Research Service Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
| | - Neeraj Srivastava
- Department of Pediatrics, United States Department of Agriculture/Agriculture Research Service Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
| | - Hanh V. Nguyen
- Department of Pediatrics, United States Department of Agriculture/Agriculture Research Service Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
| | - Teresa A. Davis
- Department of Pediatrics, United States Department of Agriculture/Agriculture Research Service Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030
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