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Esteca MV, Divino IA, Vieira da Silva AL, Severino MB, Braga RR, Ropelle ER, Simabuco FM, Baptista IL. Parkin is a critical player in the effects of caffeine over mitochondrial quality control pathways during skeletal muscle regeneration in mice. Acta Physiol (Oxf) 2024; 240:e14111. [PMID: 38314948 DOI: 10.1111/apha.14111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 01/04/2024] [Accepted: 01/12/2024] [Indexed: 02/07/2024]
Abstract
AIM This study aimed to investigate the effects of caffeine on pathways associated with mitochondrial quality control and mitochondrial capacity during skeletal muscle regeneration, focusing on the role of Parkin, a key protein involved in mitophagy. METHODS We used in vitro C2C12 myoblast during differentiation with and without caffeine in the medium, and we evaluated several markers of mitochondrial quality control pathways and myotube growth. In vivo experiments, we used C57BL/6J (WT) and Parkintm 1Shn lineage (Parkin-/- ) mice and injured tibial anterior muscle. The mice regenerated TA muscle for 3, 10, and 21 days with or without caffeine ingestion. TA muscle was used to analyze the protein content of several markers of mitochondrial quality pathways, muscle satellite cell differentiation, and protein synthesis. Furthermore, it analyzed mtDNA, mitochondrial respiration, and myofiber growth. RESULTS C2C12 differentiation experiments showed that caffeine decreased Parkin content, potentially leading to increased DRP1 and PGC-1α content and altered mitochondrial population, thereby enhancing growth capacity. Using Parkin-/- mice, we found that caffeine intake during the regenerative process induces an increase in AMPKα phosphorylation and PGC-1α and TFAM content, changes that were partly Parkin-dependent. In addition, the absence of Parkin potentiates the ergogenic effect of caffeine by increasing mitochondrial capacity and myotube growth. Those effects are related to increased ATF4 content and activation of protein synthesis pathways, such as increased 4E-BP1 phosphorylation. CONCLUSION These findings demonstrate that caffeine ingestion changes mitochondrial quality control during skeletal muscle regeneration, and Parkin is a central player in those mechanisms.
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Affiliation(s)
- M V Esteca
- Laboratory of Cell and Tissue Biology, School of Applied Sciences, University of Campinas, Limeira, Brazil
| | - I A Divino
- Laboratory of Cell and Tissue Biology, School of Applied Sciences, University of Campinas, Limeira, Brazil
| | - A L Vieira da Silva
- Laboratory of Cell and Tissue Biology, School of Applied Sciences, University of Campinas, Limeira, Brazil
| | - M B Severino
- Laboratory of Cell and Tissue Biology, School of Applied Sciences, University of Campinas, Limeira, Brazil
- Multidisciplinarity Laboratory of Food and Health, School of Applied Sciences, University of Campinas, Limeira, Brazil
| | - R R Braga
- Laboratory of Molecular Biology of Exercise, School of Applied Sciences, University of Campinas, Limeira, Brazil
| | - E R Ropelle
- Laboratory of Molecular Biology of Exercise, School of Applied Sciences, University of Campinas, Limeira, Brazil
| | - F M Simabuco
- Multidisciplinarity Laboratory of Food and Health, School of Applied Sciences, University of Campinas, Limeira, Brazil
- Department of Biochemistry, Federal University of São Paulo, São Paulo, Brazil
| | - I L Baptista
- Laboratory of Cell and Tissue Biology, School of Applied Sciences, University of Campinas, Limeira, Brazil
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Gonçalves LDS, Sales LP, Saito TR, Campos JC, Fernandes AL, Natali J, Jensen L, Arnold A, Ramalho L, Bechara LRG, Esteca MV, Correa I, Sant'Anna D, Ceroni A, Michelini LC, Gualano B, Teodoro W, Carvalho VH, Vargas BS, Medeiros MHG, Baptista IL, Irigoyen MC, Sale C, Ferreira JCB, Artioli GG. Histidine dipeptides are key regulators of excitation-contraction coupling in cardiac muscle: Evidence from a novel CARNS1 knockout rat model. Redox Biol 2021; 44:102016. [PMID: 34038814 PMCID: PMC8144739 DOI: 10.1016/j.redox.2021.102016] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/15/2021] [Accepted: 05/16/2021] [Indexed: 12/04/2022] Open
Abstract
Histidine-containing dipeptides (HCDs) are abundantly expressed in striated muscles. Although important properties have been ascribed to HCDs, including H+ buffering, regulation of Ca2+ transients and protection against oxidative stress, it remains unknown whether they play relevant functions in vivo. To investigate the in vivo roles of HCDs, we developed the first carnosine synthase knockout (CARNS1−/−) rat strain to investigate the impact of an absence of HCDs on skeletal and cardiac muscle function. Male wild-type (WT) and knockout rats (4 months-old) were used. Skeletal muscle function was assessed by an exercise tolerance test, contractile function in situ and muscle buffering capacity in vitro. Cardiac function was assessed in vivo by echocardiography and cardiac electrical activity by electrocardiography. Cardiomyocyte contractile function was assessed in isolated cardiomyocytes by measuring sarcomere contractility, along with the determination of Ca2+ transient. Markers of oxidative stress, mitochondrial function and expression of proteins were also evaluated in cardiac muscle. Animals were supplemented with carnosine (1.8% in drinking water for 12 weeks) in an attempt to rescue tissue HCDs levels and function. CARNS1−/− resulted in the complete absence of carnosine and anserine, but it did not affect exercise capacity, skeletal muscle force production, fatigability or buffering capacity in vitro, indicating that these are not essential for pH regulation and function in skeletal muscle. In cardiac muscle, however, CARNS1−/− resulted in a significant impairment of contractile function, which was confirmed both in vivo and ex vivo in isolated sarcomeres. Impaired systolic and diastolic dysfunction were accompanied by reduced intracellular Ca2+ peaks and slowed Ca2+ removal, but not by increased markers of oxidative stress or impaired mitochondrial respiration. No relevant increases in muscle carnosine content were observed after carnosine supplementation. Results show that a primary function of HCDs in cardiac muscle is the regulation of Ca2+ handling and excitation-contraction coupling.
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Affiliation(s)
- Lívia de Souza Gonçalves
- Applied Physiology & Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, SP, Brazil; Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de São Paulo, Brazil
| | - Lucas Peixoto Sales
- Applied Physiology & Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, SP, Brazil; Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de São Paulo, Brazil
| | - Tiemi Raquel Saito
- Applied Physiology & Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, SP, Brazil; Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de São Paulo, Brazil
| | | | - Alan Lins Fernandes
- Applied Physiology & Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, SP, Brazil; Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de São Paulo, Brazil
| | - José Natali
- Applied Physiology & Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, SP, Brazil
| | - Leonardo Jensen
- Laboratório de Hipertensão do Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | - Alexandre Arnold
- Laboratório de Hipertensão do Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | - Lisley Ramalho
- Institute of Biomedical Sciences, University of Sao Paulo, Brazil
| | | | - Marcos Vinicius Esteca
- Laboratory of Cell and Tissue Biology, Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Brazil
| | - Isis Correa
- Laboratório de Hipertensão do Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | - Diogo Sant'Anna
- Laboratório de Hipertensão do Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | - Alexandre Ceroni
- Departamento de Fisiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil
| | | | - Bruno Gualano
- Applied Physiology & Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, SP, Brazil; Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de São Paulo, Brazil
| | - Walcy Teodoro
- Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de São Paulo, Brazil
| | | | | | | | - Igor Luchini Baptista
- Laboratory of Cell and Tissue Biology, Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Brazil
| | - Maria Cláudia Irigoyen
- Laboratório de Hipertensão do Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | - Craig Sale
- Musculoskeletal Physiology Research Group, Sport, Health and Performance Enhancement Research Centre, Nottingham Trent University, UK
| | | | - Guilherme Giannini Artioli
- Applied Physiology & Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, SP, Brazil; Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de São Paulo, Brazil.
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Nemezio K, Yamaguchi GDC, Ramkrapes APB, Schulz ML, Baptista IL, Riani LA, Gonçalves LDS, Sale C, Medeiros MHGD, Gualano B, Artioli GG. The role of chronic muscle (in)activity on carnosine homeostasis: a study with spinal cord-injured athletes. Am J Physiol Regul Integr Comp Physiol 2021; 320:R824-R832. [PMID: 33789445 DOI: 10.1152/ajpregu.00360.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To examine the role of chronic (in)activity on muscle carnosine (MCarn) and how chronic (in)activity affects MCarn responses to β-alanine supplementation in spinal cord-injured athletes, 16 male athletes with paraplegia were randomized (2:1 ratio) to receive β-alanine (n = 11) or placebo (PL, n = 5). They consumed 6.4 g/day of β-alanine or PL for 28 days. Muscle biopsies of the active deltoid and the inactive vastus lateralis (VL) were taken before and after supplementation. MCarn in the VL was also compared with the VL of a group of individuals without paraplegia (n = 15). MCarn was quantified in whole muscle and in pools of individual fibers by high-performance liquid chromatography. MCarn was higher in chronically inactive VL vs. well-trained deltoid (32.0 ± 12.0 vs. 20.5 ± 6.1 mmol/kg DM; P = 0.018). MCarn was higher in inactive vs. active VL (32.0 ± 12.0 vs. 21.2 ± 7.5 mmol/kg DM; P = 0.011). In type-I fibers, MCarn was significantly higher in the inactive VL than in the active deltoid (38.3 ± 4.7 vs. 27.3 ± 11.8 mmol/kg DM, P = 0.014). MCarn increased similarly between inactive VL and active deltoid in the β-alanine group (VL: 68.9 ± 55.1%, P = 0.0002; deltoid: 90.5 ± 51.4%, P < 0.0001), with no changes in the PL group. MCarn content was higher in the inactive VL than in the active deltoid and the active VL, but this is probably a consequence of fiber type shift (type I to type II) that occurs with chronic inactivity. Chronically inactive muscle showed an increase in MCarn after BA supplementation equally to the active muscle, suggesting that carnosine accretion following β-alanine supplementation is not influenced by muscle inactivity.
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Affiliation(s)
- Kleiner Nemezio
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, São Paulo, Brazil
| | - Guilherme de Carvalho Yamaguchi
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, São Paulo, Brazil
| | | | | | - Igor Luchini Baptista
- Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, São Paulo, Brazil
| | - Luiz Augusto Riani
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, São Paulo, Brazil
| | - Lívia de Souza Gonçalves
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, São Paulo, Brazil
| | - Craig Sale
- Musculoskeletal Physiology Research Group, Sport, Health and Performance Enhancement Research Centre, Nottingham Trent University, Nottingham, United Kingdom
| | | | - Bruno Gualano
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, São Paulo, Brazil
| | - Guilherme Giannini Artioli
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, Faculdade de Medicina, Divisão de Reumatologia, Universidade de São Paulo, São Paulo, Brazil
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Muñoz VR, Gaspar RC, Esteca MV, Baptista IL, Vieira RFL, da Silva ASR, de Moura LP, Cintra DE, Ropelle ER, Pauli JR. Physical exercise increases ROCK activity in the skeletal muscle of middle-aged rats. Mech Ageing Dev 2020; 186:111213. [PMID: 32032622 DOI: 10.1016/j.mad.2020.111213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/17/2020] [Accepted: 01/30/2020] [Indexed: 12/23/2022]
Abstract
The physical exercise is a potential strategy to control age-related metabolic disorders, such as insulin resistance, impaired glucose homeostasis, and type 2 diabetes. Rho-kinase (ROCK) increases skeletal muscle glucose uptake through Insulin Receptor Substrate 1 (IRS1) phosphorylation. Here, we investigated the role of physical exercise in ROCK pathway in the skeletal muscle of Fischer middle-aged rats. Firstly, we observed the ROCK distribution in different skeletal muscle fiber types. ROCK signaling pathway (ROCK1 and ROCK2) and activity (pMYPT1) were higher in the soleus, which was associated with increased insulin signaling pathway (pIR, pIRS1, pPDK, pGSK3β). Middle-aged rats submitted to physical exercise, showed the upregulation of ROCK2 content and normalized RhoA (ROCK activator enzyme) levels in soleus muscle compared with middle-aged sedentary rats. These molecular changes in middle-aged exercised rats were accompanied by higher insulin signaling (pIRS1, pGSK3β, pAS160, GLUT4) in the soleus muscle. Reinforcing these findings, when pharmacological inhibition of ROCK activity was performed (using Y-27632), the insulin signaling pathway and glucose metabolism-related genes (Tpi, Pgk1, Pgam2, Eno3) were decreased in the soleus muscle of exercised rats. In summary, ROCK signaling seems to contribute with whole-body glucose homeostasis (∼50 %) through its higher upregulation in the soleus muscle in middle-aged exercised rats.
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Affiliation(s)
- Vitor Rosetto Muñoz
- Laboratory of Molecular Biology of Exercise, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil
| | - Rafael Calais Gaspar
- Laboratory of Molecular Biology of Exercise, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil
| | - Marcos Vinicius Esteca
- Laboratory of Cellular and Tissue Biology, Faculty of Applied Sciences, University of Campinas (UNICAMP), Limeira, Brazil
| | - Igor Luchini Baptista
- Laboratory of Cellular and Tissue Biology, Faculty of Applied Sciences, University of Campinas (UNICAMP), Limeira, Brazil
| | - Renan Fudoli Lins Vieira
- Laboratory of Molecular Biology of Exercise, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil
| | - Adelino Sanchez Ramos da Silva
- Postgraduate Program in Rehabilitation and Functional Performance, Ribeirão Preto Medical School, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil; School of Physical Education and Sport of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Leandro Pereira de Moura
- Laboratory of Molecular Biology of Exercise, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil; OCRC - Obesity and Comorbidities Research Center, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Dennys Esper Cintra
- School of Physical Education and Sport of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil; Laboratory of Nutritional Genomics, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil
| | - Eduardo Rochete Ropelle
- Laboratory of Molecular Biology of Exercise, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil; OCRC - Obesity and Comorbidities Research Center, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - José Rodrigo Pauli
- Laboratory of Molecular Biology of Exercise, University of Campinas (UNICAMP), Limeira, São Paulo, Brazil; OCRC - Obesity and Comorbidities Research Center, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.
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Silvestre JG, Baptista IL, Silva WJ, Cruz A, Silva MT, Miyabara EH, Labeit S, Moriscot AS. The E3 ligase MuRF2 plays a key role in the functional capacity of skeletal muscle fibroblasts. ACTA ACUST UNITED AC 2019; 52:e8551. [PMID: 31482977 PMCID: PMC6720025 DOI: 10.1590/1414-431x20198551] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 07/11/2019] [Indexed: 12/13/2022]
Abstract
Fibroblasts are a highly heterogeneous population of cells, being found in a large number of different tissues. These cells produce the extracellular matrix, which is essential to preserve structural integrity of connective tissues. Fibroblasts are frequently engaged in migration and remodeling, exerting traction forces in the extracellular matrix, which is crucial for matrix deposition and wound healing. In addition, previous studies performed on primary myoblasts suggest that the E3 ligase MuRF2 might function as a cytoskeleton adaptor. Here, we hypothesized that MuRF2 also plays a functional role in skeletal muscle fibroblasts. We found that skeletal muscle fibroblasts express MuRF2 and its siRNA knock-down promoted decreased fibroblast migration, cell border accumulation of polymerized actin, and down-regulation of the phospho-Akt expression. Our results indicated that MuRF2 was necessary to maintain the actin cytoskeleton functionality in skeletal muscle fibroblasts via Akt activity and exerted an important role in extracellular matrix remodeling in the skeletal muscle tissue.
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Affiliation(s)
- J G Silvestre
- Departamento de Anatomia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
| | - I L Baptista
- Faculdade de Ciências Aplicadas, UNICAMP, Limeira, SP, Brasil
| | - W J Silva
- Departamento de Anatomia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
| | - A Cruz
- Departamento de Anatomia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
| | - M T Silva
- Departamento de Anatomia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
| | - E H Miyabara
- Departamento de Anatomia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
| | - S Labeit
- Institute for Integrative Pathophysiology, Mannheim Medical University, Faculty for Clinical Medicine Mannheim, University of Heidelberg, Mannheim, Germany
| | - A S Moriscot
- Departamento de Anatomia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil
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Artioli GG, De Oliveira Silvestre JG, Guilherme JPLF, Baptista IL, Ramos GV, Da Silva WJ, Miyabara EH, Moriscot AS. Embryonic stem cells improve skeletal muscle recovery after extreme atrophy in mice. Muscle Nerve 2014; 51:346-52. [PMID: 24934406 DOI: 10.1002/mus.24320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2014] [Indexed: 01/02/2023]
Abstract
INTRODUCTION We injected embryonic stem cells into mouse tibialis anterior muscles subjected to botulinum toxin injections as a model for reversible neurogenic atrophy. METHODS Muscles were exposed to botulinum toxin for 4 weeks and allowed to recover for up to 6 weeks. At the onset of recovery, a single muscle injection of embryonic stem cells was administered. The myofiber cross-sectional area, single twitch force, peak tetanic force, time-to-peak force, and half-relaxation time were determined. RESULTS Although the stem cell injection did not affect the myofiber cross-sectional area gain in recovering muscles, most functional parameters improved significantly compared with those of recovering muscles that did not receive the stem cell injection. CONCLUSIONS Muscle function recovery was accelerated by embryonic stem cell delivery in this durable neurogenic atrophy model. We conclude that stem cells should be considered a potential therapeutic tool for recovery after extreme skeletal muscle atrophy.
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Affiliation(s)
- Guilherme Giannini Artioli
- Laboratory of Cellular and Molecular Biology of Striated Muscle, Department of Anatomy, Institute of Biomedical Sciences, Avenida Prof. Lineu Prestes 2415, São Paulo CEP 05508-000, Brazil; Laboratory of Applied Nutrition and Metabolism, School of Physical Education and Sport, Department of Biodynamics, University of São Paulo, São Paulo, SP, Brazil
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Miyabara EH, Baptista IL, Lomonte B, Selistre-de-Araújo HS, Gutiérrez JM, Moriscot AS. Effect of calcineurin inhibitors on myotoxic activity of crotoxin and Bothrops asper phospholipase A2 myotoxins in vivo and in vitro. Comp Biochem Physiol C Toxicol Pharmacol 2006; 143:284-94. [PMID: 16635590 DOI: 10.1016/j.cbpc.2006.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2005] [Revised: 03/03/2006] [Accepted: 03/06/2006] [Indexed: 10/24/2022]
Abstract
Previous studies have shown that calcineurin activity plays a critical role in the myotoxic activity induced by crotoxin (CTX), a group II phospholipase A(2) (PLA(2)) with neurotoxic and myotoxic actions. In order to address whether calcineurin is also important for the activity of non-neurotoxic group II PLA(2) myotoxins we have compared the effects of calcineurin inhibition on the myotoxic capacity of CTX and the non-neurotoxic PLA(2)s, myotoxin II (Mt II) and myotoxin III (Mt III) from Bothrops asper venom. Rats were treated with cyclosporin A (CsA) or FK506, calcineurin inhibitors, and received an intramuscular injection of either CTX, Mt II or Mt III into the tibialis anterior. Animals were killed 24 h after injection of toxins. Tibialis anterior was removed and stored in liquid nitrogen. Myofibers in culture were also treated with CsA or FK506 and exposed to CTX, Mt II and Mt III. It was observed that, in contrast to CTX, CsA and FK506 do not attenuate myotoxic effects induced by both Mt II and Mt III in vivo and in vitro. The results of the present study suggest that calcineurin is not essential for the myotoxic activity of Mt II and Mt III, indicating that distinct intracellular pathways might be involved in myonecrosis induced by neurotoxic CTX and non-neurotoxic Bothrops sp. PLA(2) myotoxins. Alternatively, calcineurin dependent fast fiber type shift might render the muscle resistant to the action of CTX, without affecting its susceptibility to Bothrops sp. myotoxins.
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Affiliation(s)
- E H Miyabara
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, Av Lineu Prestes 1524, São Paulo, 05508-900, SP, Brazil
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