Elevated serum Activin A in chronic obstructive pulmonary disease with skeletal muscle wasting

OBJECTIVE: Muscle wasting contributes to the reduced quality of life and increased mortality in chronic obstructive pulmonary disease (COPD). Muscle atrophy in mice with cachexia was caused by Activin A binding to ActRIIB. The role of circulating Activin A leading to muscle atrophy in COPD remains elusive. METHODS: In the present study, we evaluated the relationship between serum levels of Activin A and skeletal muscle wasting in COPD patients. The expression levels of serum Activin A were measured in 78 stable COPD patients and in 60 healthy controls via ELISA, which was also used to determine the expression of circulating TNF-α levels. Total skeletal muscle mass (SMM) was calculated according to a validated formula by age and anthropometric measurements. The fat-free mass index (FFMI) was determined as the fat-free mass (FFM) corrected for body surface area. RESULTS: Compared to the healthy controls, COPD patients had upregulated Activin A expression. The elevated levels of Activin A were correlated with TNF-α expression, while total SMM and FFMI were significantly decreased in COPD patients. Furthermore, serum Activin A expression in COPD patients was negatively associated with both FFMI and BMI. CONCLUSION: The above results showed an association between increased circulating Activin A in COPD patients and the presence of muscle atrophy. Given our previous knowledge, we speculate that Activin A contributes to skeletal muscle wasting in COPD.

Effect of physical training on liver expression of activin A and follistatin in a nonalcoholic fatty liver disease model in rats

Nonalcoholic fatty liver disease (NAFLD) is characterized by fat accumulation in the liver and is associated with obesity and insulin resistance. Activin A is a member of the transforming growth factor beta (TGF)-β superfamily and inhibits hepatocyte growth. Follistatin antagonizes the biological actions of activin. Exercise is an important therapeutic strategy to reduce the metabolic effects of obesity. We evaluated the pattern of activin A and follistatin liver expression in obese rats subjected to swimming exercise. Control rats (C) and high-fat (HF) diet-fed rats were randomly assigned to a swimming training group (C-Swim and HF-Swim) or a sedentary group (C-Sed and HF-Sed). Activin βA subunit mRNA expression was significantly higher in HF-Swim than in HF-Sed rats. Follistatin mRNA expression was significantly lower in C-Swim and HF-Swim than in either C-Sed or HF-Sed animals. There was no evidence of steatosis or inflammation in C rats. In contrast, in HF animals the severity of steatosis ranged from grade 1 to grade 3. The extent of liver parenchyma damage was less in HF-Swim animals, with the severity of steatosis ranging from grade 0 to grade 1. These data showed that exercise may reduce the deleterious effects of a high-fat diet on the liver, suggesting that the local expression of activin-follistatin may be involved.

Bases ambientales y genéticas de las fisuras orofaciales: revisión / Narrative review: environmental and genetic basis of orofacial clefts

El desarrollo embriológico de las estructuras orofaciales es un proceso complejo guiado por programas genéticos. Alteraciones en esos procesos dan lugar a anomalías estructurales. Un ejemplo de ellas son las fisuras de labio y el paladar. Las principales vías involucradas en las fisuras tienen como participantes a las familias del factor de crecimiento fibroblástico (FGF), Hedgehog (HH), Wingless (WNT) y la familia del factor de crecimiento transformante beta (TGFß), que incluye las proteínas morfogenéticas del hueso (BMPs) y activinas. En esta revisión narrativa se presentan algunos de los procesos celulares, moleculares y factores ambientales implicados en el desarrollo del complejo orofacial, finalizando con posibilidades terapéuticas para la evidencia acumulada.

Complex genetic process guides the embryonic head development. Alterations in these processes result instructural abnormalities. An example of these are the cleft lip and palate. The major pathways involved in the fissures are families: the Fibroblast Growth Factor (FGF) family, the Hedgehog (HH) family, the Wingless (WNT) family and the Transforming Growth Factor beta (TGF-ß) family, which includes the Bone Morphogenetic Proteins (BMPs) and Activins. In this review, we discuss some of the celular/molecular processes and environmental factors involved in the development of the orofacial complex, ending with therapeutic possibilities and potential clinical relevance to the accumulated evidence.

Endometriose: papel da superfamília do fator transformador de crescimento beta / Endometriosis: the role of transforming growth factor β superfamily

A endometriose é uma condição ginecológica, que atinge mulheres em idade reprodutiva e pode ser causa de dor e infertilidade. A patogênese da doença é multifatorial e envolve a perda da capacidade de diferenciação das células endometrióticas, moléculas de adesão celular para adesão do endométrio ao peritônio, neoangiogênese, características do fluido peritoneal e alterações do sistema imune. A superfamília do fator transformador de crescimento β (TGF-β) parece exercer papéis importantes na implantação e manutenção do tecido ectópico na endometriose. Ativinas, inibinas, folistatina, hormônio anti-mülleriano e as proteínas morfogenéticas ósseas são membros da superfamília do TGF-β. Estas moléculas são expressas no endométrio humano e apresentam ações importantes na proliferação celular, diferenciação celular, função imune, regulação da apoptose e remodelamento dos tecidos, apresentando, por conseguinte, um importante papel no ciclo menstrual, decidualização do endométrio e no início da gestação. Este artigo objetiva rever os achados sobre tais proteínas no endométrio e seus possíveis papéis na gênese e fisiopatologia da endometriose

Endometriosis is a gynecological pathological entity typical of women in reproductive age, associated with pelvic pain and infertility. The pathogenesis of the disease is multifactorial and it involves loss of the endometriotic cell differentiation, cell adhesion, neo-angiogenesis, peritoneal fluid characteristics, and changes in the immune system. The transforming growth factor β (TGF-β) superfamily seems to play important roles in the implementation and maintenance of ectopic tissue in endometriosis. Activin, inhibin, follistatin, anti-Mullerian hormone, and bone morphogenetic proteins are members of the superfamily of TGF-β. The TGF-β and family members are expressed by human endometrium and act on cell proliferation, differentiation, immune function, apoptosis and tissue remodeling, playing a role in menstrual cycle, decidualization, and early pregnancy. The aim of this study is to review the findings about these molecules in the endometrium and their possible roles in the genesis and pathophysiology of endometriosis

Expression of SMAD proteins, TGF-beta/activin signaling mediators, in human thyroid tissues / Expressão de proteínas SMAD, mediadores da sinalização de TGF-beta/activina, em tecidos de tiroide humana

OBJECTIVE: To investigate the expression of SMAD proteins in human thyroid tissues since the inactivation of TGF-β/activin signaling components is reported in several types of cancer. Phosphorylated SMAD 2 and SMAD3 (pSMAD2/3) associated with the SMAD4 induce the signal transduction generated by TGF-β and activin, while SMAD7 inhibits this intracellular signaling. Although TGF-β and activin exert antiproliferative roles in thyroid follicular cells, thyroid tumors express high levels of these proteins. MATERIALS AND METHODS: The protein expression of SMADs was evaluated in multinodular goiter, follicular adenoma, papillary and follicular carcinomas by immunohistochemistry. RESULTS: The expression of pSMAD2/3, SMAD4 and SMAD7 was observed in both benign and malignant thyroid tumors. Although pSMAD2/3, SMAD4 and SMAD7 exhibited high cytoplasmic staining in carcinomas, the nuclear staining of pSMAD2/3 was not different between benign and malignant lesions. CONCLUSIONS: The finding of SMADs expression in thyroid cells and the presence of pSMAD2/3 and SMAD4 proteins in the nucleus of tumor cells indicates propagation of TGF-β/activin signaling. However, the high expression of the inhibitory SMAD7, mostly in malignant tumors, could contribute to the attenuation of the SMADs antiproliferative signaling in thyroid carcinomas.

OBJETIVO: Investigar a expressão de proteínas SMAD em tecidos de tiroide humana desde que a inativação dos componentes da sinalização de TGF-β/activina é relatada em diversos tipos de câncer. SMAD 2 e SMAD3 fosforilados (pSMAD2/3) associados com SMAD4 induzem a transmissão do sinal gerado por TGF-β e activina, enquanto SMAD7 inibe essa sinalização intracelular. Embora TGF-β e activina exerçam efeitos antiproliferativos nas células foliculares da tiroide, tumores de tiroide expressam altos níveis dessas proteínas. MATERIAIS E MÉTODOS: A expressão proteica de SMADs foi avaliada em bócio multinodular, adenoma folicular, carcinomas papilífero e folicular por imuno-histoquímica. RESULTADOS: A expressão de pSMAD2/3, SMAD4 e SMAD7 foi observada tanto em tumores benignos como malignos da tiroide. Embora pSMAD2/3, SMAD4 e SMAD7 exibissem alta positividade citoplasmática em carcinomas, a positividade nuclear de pSMAD2/3 não foi diferente entre lesões benignas e malignas da tiroide. CONCLUSÕES: O achado da expressão de SMADs em células tiroidianas e a presença das proteínas pSMAD2/3 e SMAD4 no núcleo de células tumorais indicam propagação da sinalização TGF-β/activina. Contudo, a alta expressão de SMAD7 inibitório, principalmente em tumores malignos, poderia contribuir para atenuação da sinalização antiproliferativa de SMADs em carcinomas de tiroide.

TGFbeta, activina e sinalização SMAD em câncer de tiróide / TGFbeta, activin and SMAD signalling in thyroid cancer

TGFbeta e activina são membros da superfamília TGFbeta e desempenham um amplo papel no desenvolvimento, proliferação e apoptose. Estes fatores de crescimento exercem seus efeitos biológicos ligando-se a receptores de membrana do tipo I e do tipo II que transduzem a sinalização até o núcleo através da fosforilação das proteínas R-SMADs (SMAD 2/3) e co-SMADs (SMAD4). O controle apropriado da via de TGFbeta/activina ainda depende da regulação negativa exercida pelo SMAD inibitório (SMAD7) e pelas enzimas E3 de ubiquitinação (Smurfs). Fisiologicamente, TGFbeta e activina atuam como potentes inibidores da proliferação na célula folicular tiroidiana. Desta forma, alterações de receptores e componentes da via de sinalização SMAD estão associadas a diferentes tipos de tumores. Desde que TGFbeta e activina geram sua sinalização intracelular utilizando os mesmos componentes da via SMAD, o desequilíbrio desta via prejudica dois processos anti-mitogênicos da célula. Nesta revisão, enfocamos aspectos que indicam o mecanismo de resistência ao efeito inibitório de TGFbeta e activina ocasionado pelo desequilíbrio da via de sinalização SMAD nas neoplasias da tiróide.

TGFbeta and activin are members of the TGFbeta superfamily and play a wide role in development, proliferation and apoptosis. These growth factors exert their biological effects by binding to the type I and II membrane receptors to transduce their signalling through the nucleus by phosphorylation of R-SMADs (SMAD 2/3) and co-SMADs (Smad 4). The proper control of TGFbeta/activin pathway is negatively regulated by inhibitory SMAD (SMAD7) and by E3 ubiquitination enzymes (Smurfs). Physiologically, TGFbeta and activin act as potent growth inhibitors in thyroid follicular cell. Thus, alterations in the receptors and components of SMAD signalling pathway are associated with several types of tumors. Since TGFbeta and activin generate their intracellular signalling through the same components of the SMAD pathway, the unbalance of this pathway impairs both of anti-mitogenic signals in the cell. This review addresses aspects of the molecular mechanisms in the understanding of resistance to the growth inhibitory effects of TGFbeta and activin due to the disequilibrium in the SMAD inhibitory pathway in thyroid neoplasia.