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1.
Growth Horm IGF Res ; 53-54: 101323, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32408253

RESUMEN

OBJECTIVE: Insulin-like growth factor I (IGF1) is an important regulator of collagen and extracellular matrix protein expression. We aimed to evaluate the effect of amino acids (AAs) on expression of IGF1 and IGF1-dependent genes in human myotubes and skeletal muscle and supposed that AAs administration increases IGF1 levels in blood and expression of IGF1 and IGF1-dependent genes in trained skeletal muscle, thereby reducing training-induced muscle damage. DESIGN: Human myotubes were incubated with Arg and Leu for 24 h. Then, the effects of long-term branched chain AAs administration (10 weeks, 0.1 g/kg body mass/day) to volunteers (six subjects per AAs and placebo groups) performing large training volumes regularly (cross country skiers, training twice a day) were examined. RESULTS: Incubating the myotubes with AAs increases expression of IGF1 mRNA isoforms and IGF1 secretion by 2-3 times. In athletes, long-term AAs administration increased basal blood levels of IGF1 (~50%) and expression of IGF1Ea mRNA slightly in skeletal muscle. There is no marked increase in expression of COL1A1, COL3A1, COL5A1, and LOX genes in skeletal muscle after AAs administration. However, expression of these genes in the combined group (placebo + AAs; n = 12) significantly correlated with the expression of IGF1Ea mRNA in muscle and did not correlate with IGF1 levels in the blood. CONCLUSIONS: AAs administration increases IGF1 expression in vitro and in vivo. To obtain more pronounced changes in expression of IGF1 and IGF1-dependent genes in skeletal muscle, it may be necessary to increase the dose and/or duration of AAs administration.


Asunto(s)
Arginina/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Factor I del Crecimiento Similar a la Insulina/metabolismo , Leucina/farmacología , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , Adulto , Humanos , Factor I del Crecimiento Similar a la Insulina/genética , Masculino , Fibras Musculares Esqueléticas/efectos de los fármacos , Músculo Esquelético/efectos de los fármacos , Adulto Joven
2.
Cytokine ; 128: 154991, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32000013

RESUMEN

The effects of glycated albumin on the expression of inflammatory cytokines in differentiated myotubes were investigated. Glycated albumin stimulates the expression of TNF α, IL-1ß, IL-6 and CCL-2 both at the mRNA and protein levels via the receptor of AGEs. Various cytokines demonstrated different kinetics of stimulation by glycated albumin. At a high glucose concentration, the stimulation effect was more pronounced than at a low one. At physiological concentrations of albumin and fructosamine, the stimulation effect of glycated albumin on inflammatory cytokine expression in myotubes was also observed. The induction of expression of all studied cytokines was sensitive to the inhibitors of JNK, p38 MAPK, MEK1/2, Src family protein kinases and NF-κB. At the same time, the induction of TNFα and IL-1ß was diminished by the Ca2+/calmodulin-dependent protein kinase inhibitor, whereas the induction of IL-6 and CCL-2 was reduced by the inhibitor of phosphoinositide 3-kinase. Possible implications of observed stimulation of cytokine expression by glycated albumin in the development of diabetes mellitus symptoms are discussed.


Asunto(s)
Citocinas/genética , Inflamación/genética , Células Musculares/metabolismo , Albúmina Sérica/genética , Células Cultivadas , Productos Finales de Glicación Avanzada , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos/genética , Sistema de Señalización de MAP Quinasas/genética , Proteínas Quinasas Activadas por Mitógenos/genética , FN-kappa B/genética , Fosfatidilinositol 3-Quinasas/genética , Transducción de Señal/genética , Factor de Necrosis Tumoral alfa/genética , Proteínas Quinasas p38 Activadas por Mitógenos/genética , Albúmina Sérica Glicada
3.
Biochem Biophys Rep ; 18: 100627, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30957033

RESUMEN

The effects of potassium chloride on the expression of IGF-1 splice forms and myoblast proliferation were investigated. KCl at the concentrations of 7-12 mM stimulated the synthesis of IGF-1 and mechano growth factor (MGF) in murine myoblasts as well as in myotubes both at the mRNA and protein levels. Pan-calcium channel blocker CdCl2 completely abolished stimulation of growth factor expression, whereas blocker of HCN and Nav1.4 channels ZD7288 drastically reduced it. In addition, potassium chloride stimulated myoblast proliferation, while IGF-1 autocrine signaling inhibition partially suppressed these mitogenic effects.

4.
Biochem Biophys Rep ; 9: 226-231, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28956009

RESUMEN

Myofibrillar proteins titin and myomesin stimulated myoblast proliferation as determined by MTT-test and labelled thymidine incorporation in the DNA. Specific Fn type III and Ig-like domains of these proteins were able to exert mitogenic effects as well. Proliferative effect of Fn type III domains was highly sensitive to inhibition of Ca2+/calmodulin dependent protein kinase, whereas the effect of Ig-like domains showed greater sensitivity to the inhibition of adenylyl cyclase - cAMP - PKA pathway. IGF-1 autocrine signalling inhibition partially suppressed mitogenic effects revealed by both domain types.

5.
Muscle Nerve ; 51(3): 434-42, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24916884

RESUMEN

INTRODUCTION: We investigated the effect of resistance exercise intensity and exercise-induced metabolic stress on the activation of anabolic signaling and expression of myogenic genes in skeletal muscle. METHODS: Ten strength-trained athletes performed high-intensity [HI, 74% of 1-repetition maximum (RM)], middle-intensity (MI, 54% 1RM), or middle-intensity (54% 1RM) no-relaxation exercise (MIR). Kinase phosphorylation level and myogenic gene expression in muscle samples were evaluated before, 45 min, 5 h, and 20 h after exercise. RESULTS: The lactate concentration in MI was approximately 2-fold lower than in the 2 other sessions, and was highest in MIR. The phosphorylation level of extracellular kinase 1/2Thr202/Tyr204 after exercise was related to metabolic stress. Metabolic stress induced a decrease in myostatin mRNA expression, whereas mechano-growth factor mRNA level depended on exercise intensity. CONCLUSIONS: This study demonstrates that both intensity and exercise-induced metabolic stress can be manipulated to affect muscle anabolic signaling.


Asunto(s)
Sistema de Señalización de MAP Quinasas/fisiología , Músculo Esquelético/metabolismo , Miostatina/biosíntesis , Entrenamiento de Fuerza/métodos , Factor de Transcripción STAT5/biosíntesis , Estrés Fisiológico/fisiología , Proteínas Supresoras de Tumor/biosíntesis , Regulación de la Expresión Génica , Humanos , Masculino , Adulto Joven
6.
Mol Cell Endocrinol ; 399: 69-77, 2015 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-25152160

RESUMEN

Expression of insulin-like growth factor 1 (IGF-1) mRNAs splice forms was recently shown to be stimulated by myofibrillar proteins released from the damaged muscle. In this study, we report that individual subfragments of titin and myomesin composed of Fn type III and Ig-like domains can activate expression of two IGF-1 splice forms in cultured myoblasts, both at protein and mRNA levels. Competition studies showed that each of the domain-types interacts with its own receptor. Induction of IGF-1 expression caused by domains of different types showed dissimilar sensitivity to inhibitors of regulatory cascades. The effect of Fn type III domains was more sensitive to inhibition of Ca(2+)/calmodulin dependent protein kinase, whereas the effect of Ig-like domains showed greater sensitivity to the inhibition of the adenylyl cyclase-cAMP-PKA pathway.


Asunto(s)
Empalme Alternativo/efectos de los fármacos , Conectina/farmacología , Factor I del Crecimiento Similar a la Insulina/biosíntesis , Mioblastos/metabolismo , Humanos , Factor I del Crecimiento Similar a la Insulina/genética , Mioblastos/citología , Estructura Terciaria de Proteína , ARN Mensajero/biosíntesis , ARN Mensajero/genética
7.
Mol Cell Biochem ; 363(1-2): 347-55, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22160926

RESUMEN

Mechano-growth factor (MGF) is a product of alternative splicing of the insulin-like growth factor 1 (IGF-1) mRNA. MGF is known to stimulate myoblast proliferation and to protect neurons and cardiomyocytes from apoptosis. MGF expression is dramatically increased in response to mechanical stimuli and tissue damage. The mechanisms of induction of MGF expression are as yet imperfectly understood. There is certain evidence that some protein factors able to stimulate MGF synthesis in normal myoblasts are released from damaged muscle. This study was undertaken to explore the nature of these protein inductors of MGF expression and to investigate the mechanism of their action. We report here that myofibrillar fraction of skeletal muscle homogenate activated MGF expression in murine myoblasts and myotubes in culture. The expression of another splice form of IGF-1 gene, IGF-1Ea, was also stimulated by myofibrils. Three myofibrillar proteins able to stimulate MGF synthesis were isolated. These proteins were identified by MALDI and immunoblotting as myomesin, myosin-binding protein C, and titin. The activation of MGF expression was associated with the increase of cAMP level in the cells. Inhibitor of adenylyl cyclase dideoxyadenosine arrested stimulation of MGF synthesis by all three myofibrillar proteins.


Asunto(s)
Proteínas Contráctiles/metabolismo , Factor I del Crecimiento Similar a la Insulina/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Mioblastos/metabolismo , Miofibrillas/metabolismo , Inhibidores de Adenilato Ciclasa , Adenilil Ciclasas/metabolismo , Empalme Alternativo , Animales , Western Blotting , Proteínas Portadoras/metabolismo , Células Cultivadas , Colforsina/farmacología , Conectina , AMP Cíclico/metabolismo , Didesoxiadenosina/farmacología , Activación Enzimática , Activadores de Enzimas/farmacología , Inhibidores Enzimáticos/farmacología , Factor I del Crecimiento Similar a la Insulina/genética , Ratones , Fibras Musculares Esqueléticas/efectos de los fármacos , Proteínas Musculares/metabolismo , Mioblastos/efectos de los fármacos , Miofibrillas/efectos de los fármacos , Proteínas Quinasas/metabolismo , Proteómica/métodos , ARN Mensajero/metabolismo , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Regulación hacia Arriba
8.
Arch Biochem Biophys ; 507(2): 323-31, 2011 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-21192914

RESUMEN

The effect of second messengers on the expression of mechano-growth factor (MGF) synthesis by myoblasts and differentiated myotubes in culture was investigated. cAMP stimulates MGF expression both in murine and human cells. CNG- and HCN-channel blockers slightly activated MGF synthesis, while an activator of Epac protein had no effect. It is assumed that cAMP activates MGF synthesis via protein kinase A. Phorbol ester (PMA) activates MGF synthesis in human myoblasts and myotubes only. The expression of another splice form of IGF-1 gene, IGF-1Ea, was also stimulated in human cells by db-cAMP and PMA and in murine cells by db-cAMP only. Stimulation of MGF expression in human cells by db-cAMP and PMA demonstrated different time dependences but showed additivity when the compounds were applied in a combination. Inhibitors specific to protein kinase A did not affect PMA-mediated activation, while inhibitors specific to protein kinase C did not affect db-cAMP-mediated process. Ca²+ ionophore and ROS inductor strongly inhibited synthesis of the growth factor. PGE2 known as physiological stimulator of cAMP synthesis was shown to stimulate MGF expression both in murine and human cells. Implication of protein kinase A and protein kinase C in MGF synthesis stimulation and a cross-talk between two signaling systems is discussed.


Asunto(s)
Regulación de la Expresión Génica , Factor I del Crecimiento Similar a la Insulina/genética , Factor I del Crecimiento Similar a la Insulina/metabolismo , Sistemas de Mensajero Secundario , Adolescente , Animales , Diferenciación Celular/efectos de los fármacos , AMP Cíclico/metabolismo , Dinoprostona/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Factor I del Crecimiento Similar a la Insulina/biosíntesis , Masculino , Ratones , Fibras Musculares Esqueléticas/citología , Fibras Musculares Esqueléticas/efectos de los fármacos , Fibras Musculares Esqueléticas/metabolismo , Mioblastos/citología , Mioblastos/efectos de los fármacos , Mioblastos/metabolismo , Sistemas de Mensajero Secundario/efectos de los fármacos , Factores de Tiempo , Adulto Joven
9.
Biochem Biophys Res Commun ; 375(2): 271-4, 2008 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-18706390

RESUMEN

The effect of cellular stress factors, the hyperthermia and the acidification of culture medium, on mechano-growth factor (MGF) synthesis by murine myoblasts in culture was investigated. Hyperthermia was shown to stimulate MGF expression both in primary myoblasts and in differentiated multinuclear myotubes. The induction of MGF synthesis peaked at 40 degrees capital ES, Cyrillic, with some activation at 39 and 41 degrees capital ES, Cyrillic. Decrease of culture medium pH stimulated MGF expression with a maximum at pH 6.3. Hydrocortisone eliminated induction of MGF synthesis completely both under hyperthermia and acidification conditions.


Asunto(s)
Ácidos , Calor , Factor I del Crecimiento Similar a la Insulina/biosíntesis , Fibras Musculares Esqueléticas/metabolismo , Mioblastos/metabolismo , Ácidos/farmacología , Animales , Células Cultivadas , Concentración de Iones de Hidrógeno , Ratones , Fibras Musculares Esqueléticas/efectos de los fármacos , Mioblastos/efectos de los fármacos
10.
Hybridoma (Larchmt) ; 25(5): 300-5, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17044786

RESUMEN

Two hybridoma clones secreting monoclonal antibodies (MAbs) to mechano-growth factor (MGF) have been produced by cell fusion technique. Isotyping of the MAbs revealed that both belong to the G1 subclass. The epitope specificity of the MAbs has been examined in competition experiments. No competition was detected, suggesting that the MAbs obtained recognize different antigenic determinants. MAbs of one clone (8B9) recognize human MGF peptide absent in insulin-like growth factor-1 (IGF-1) and comprising amino acids from 87 to 111. Affinity binding constants with the full-length MGF and 87-111 amino acid peptide have been determined by enzyme-linked immunosorbent assay (ELISA). A pair of monoclonal antibodies obtained can be used in a sandwich-type assay to quantify MGF.


Asunto(s)
Anticuerpos Monoclonales/biosíntesis , Factor I del Crecimiento Similar a la Insulina/inmunología , Isoformas de Proteínas/inmunología , Animales , Anticuerpos Monoclonales/aislamiento & purificación , Afinidad de Anticuerpos , Especificidad de Anticuerpos , Unión Competitiva , Células Cultivadas , Reacciones Cruzadas , Ensayo de Inmunoadsorción Enzimática/métodos , Humanos , Hibridomas/metabolismo , Técnicas Inmunológicas , Ratones , Ratones Endogámicos BALB C
11.
Oncogene ; 23(54): 8834-40, 2004 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-15480427

RESUMEN

Exposure to asbestos fibers increases the risk of development of mesotheliomas and lung carcinomas, but not fibrosarcomas. We present data suggesting that resistance of fibroblasts to asbestos-induced carcinogenesis is likely to be connected with their lower ability to generate reactive oxygen species (ROS) in response to asbestos exposure and stricter control of proliferation of cells bearing asbestos/ROS-induced injuries. In fact, chrysotile (Mg6Si4O10(OH)8) asbestos exposure (5-10 microg/cm2) increased intracellular ROS and 8-oxo-guanine contents in rat pleural mesothelial cells, but not in lung fibroblasts. Simultaneously, moderate dosages of chrysotile and other agents increasing ROS levels (hydrogen peroxide, H2O2 and ethyl-methanesulfonate, EMS) inhibited cell cycle progression, in particular G1-to-S transition, in fibroblasts, but not in mesothelial cells. The arrested fibroblasts underwent cell death, while the majority of chrysotile-treated mesothelial cells survived. The differences in cell cycle response to asbestos/ROS-induced injuries correlated with distinct activity of p53-p21Cip1/Waf1 pathway in the two cell types. Chrysotile, H2O2 and EMS caused p53 upregulation in both cell types, but mesothelial cells, unlike fibroblasts, showed no accumulation of p21Cip1/Waf1. Of note, treatment with doxorubicin caused similar p53-dependent p21Cip1/Waf1 upregulation and cell cycle arrest in both cell types. This suggests differential response of fibroblasts and mesothelial cells specifically to asbestos/ROS exposure rather than to all DNA-damaging insults.


Asunto(s)
Asbestos Serpentinas/toxicidad , ADN/efectos de los fármacos , Fase G1 , Especies Reactivas de Oxígeno , Animales , Northern Blotting , Western Blotting , División Celular/efectos de los fármacos , Células Cultivadas , ADN/metabolismo , Oxidación-Reducción , Pleura/citología , Pleura/efectos de los fármacos , Ratas , Ratas Wistar
12.
Teratog Carcinog Mutagen ; Suppl 1: 207-14, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12616610

RESUMEN

The report is devoted to the investigation of cytotoxic action of macrophages and asbestos on transformed mesothelium and mesothelioma cells, the characterization of its specificity, and the nature of the factors mediating it. The viability of different cells after asbestos exposure was studied in co-culture with macrophages. Mesothelioma cell lines obtained from tumors developed in vivo were the most sensitive to the cytotoxic action of macrophages and asbestos. Mesothelium cells of late passages and ras-transformed cell lines IAR2 and Rat1 were somewhat less sensitive, whereas untransformed cells of IAR2 and Rat1 lines and early passage mesothelium were low sensitive to that cytotoxic action. In experiments performed on Petri dishes with inserts that allowed treatment with asbestos of only one of two cell populations, it was shown that asbestos treatment of mesothelioma cells was necessary and sufficient for manifestation of cytotoxic effect (in the absence of macrophages asbestos caused very low cytotoxicity). The medium conditioned by macrophages was not cytototoxic by itself but it strongly enhanced cytotoxic action of asbestos on transformed mesothelium and mesothelioma cells but not on normal mesothelial cells and IAR2 and Rat1 cells (both normal and ras-transformed). The specificity of this augmenting effect for different toxicants was also investigated. It was shown that medium conditioned by macrophages enhanced cytotoxicity of hydrogen peroxide and sodium azide but not that of nonfibrous silicon dioxide, ethylmethanesulfonate, and sodium dodecylsulfate. The factor mediating this effect is thermolabile, non-dialyzable and protease-sensitive. Its m.w. is approximately 3-5 kD.


Asunto(s)
Transformación Celular Neoplásica/efectos de los fármacos , Citotoxinas/metabolismo , Citotoxinas/toxicidad , Células Epiteliales/efectos de los fármacos , Macrófagos Peritoneales/metabolismo , Cavidad Pleural/efectos de los fármacos , Animales , Amianto/toxicidad , Línea Celular Transformada , Transformación Celular Neoplásica/patología , Células Epiteliales/citología , Mesotelioma/metabolismo , Mesotelioma/patología , Neoplasias Experimentales/metabolismo , Neoplasias Experimentales/patología , Neoplasias Peritoneales/metabolismo , Neoplasias Peritoneales/patología , Cavidad Pleural/citología , Ratas , Ratas Wistar , Células Tumorales Cultivadas
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