Clinical Science (2015) 128, 307–319 (Printed in Great Britain) doi: 10.1042/CS20140215 Angiotensin-(1–7) decreases skeletal muscle atrophy induced by angiotensin II through a Mas receptor-dependent mechanism Franco Cisternas ∗1 , Mar´ ıa Gabriela Morales ∗1 , Carla Meneses ∗ , Felipe Simon†‡, Enrique Brandan§, Johanna Abrigo ∗ , Yaneisi Vazquez ∗ and Claudio Cabello-Verrugio ∗ ∗ Laboratorio de Biolog´ ıa y Fisiopatolog´ ıa Molecular, Departamento de Ciencias Biol´ ogicas, Facultad de Ciencias Biol´ ogicas & Facultad de Medicina, Universidad Andres Bello, Santiago, Chile †Laboratorio de Fisiopatolog´ ıa Integrativa, Departamento de Ciencias Biol´ ogicas, Facultad de Ciencias Biol´ ogicas & Facultad de Medicina, Universidad Andres Bello, Santiago, Chile ‡Millennium Institute on Immunology and Immunotherapy, Santiago, Chile §Centro de Regulaci´ on Celular y Patolog´ ıa (CRCP), Centro de Regeneraci´ on y Envejecimiento (CARE), Laboratorio de Diferenciaci´ on Celular y Patolog´ ıa, Departamento de Biolog´ ıa Celular y Molecular, MIFAB, Pontificia Universidad Cat´ olica de Chile, Santiago, Chile Abstract Skeletal muscle atrophy is a pathological condition characterized by the loss of strength and muscle mass, an increase in myosin heavy chain (MHC) degradation and increase in the expression of two muscle-specific ubiquitin ligases: atrogin-1 and MuRF-1. Angiotensin II (AngII) induces muscle atrophy. Angiotensin-(1–7) [Ang-(1–7)], through its receptor Mas, produces the opposite effects than AngII. We assessed the effects of Ang-(1–7) on the skeletal muscle atrophy induced by AngII. Our results show that Ang-(1–7), through Mas, prevents the effects induced by AngII in muscle gastrocnemius: the decrease in the fibre diameter, muscle strength and MHC levels and the increase in atrogin-1 and MuRF-1. Ang-(1–7) also induces AKT phosphorylation. In addition, our analysis in vitro using C 2 C 12 myotubes shows that Ang-(1–7), through a mechanism dependent on Mas, prevents the decrease in the levels of MHC and the increase in the expression of the atrogin-1 and MuRF-1, both induced by AngII. Ang-(1–7) induces AKT phosphorylation in myotubes; additionally, we demonstrated that the inhibition of AKT with MK-2206 decreases the anti-atrophic effects of Ang-(1–7). Thus, we demonstrate for the first time that Ang-(1–7) counteracts the skeletal muscle atrophy induced by AngII through a mechanism dependent on the Mas receptor, which involves AKT activity. Our study indicates that Ang-(1–7) is novel molecule with a potential therapeutical use to improve muscle wasting associated, at least, with pathologies that present high levels of AngII. Key words: angiotensin-(1–7), atrophy, Mas, muscle wasting, skeletal muscle INTRODUCTION Skeletal muscle atrophy is the loss of muscle mass concomit- antly with a decrease in strength generated by muscle wasting. Several characteristic features are observed in skeletal muscle at- rophy, such as the decrease in the sarcomeric proteins as the heavy and light chains of myosin, which is translated into a decrease in the generation of net force [1,2]. The causes of skeletal muscle atrophy are diverse and include chronic diseases such as cardiac, renal and pulmonary failure [3–7]. One of the Abbreviations: AngII, angiotensin II; Ang-(1–7), angiotensin-(1–7); ACE, angiotensin-converting enzyme; AT 1 R, angiotensin type 1 receptor; AT 2 R, angiotensin type 2 receptor; FoxO, forkhead box O; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; IGF-1, insulin-like growth factor-I; MHC, myosin heavy chain; RAS, renin–angiotensin system; UPS, ubiquitin–proteasome system; WGA, wheat germ agglutinin. 1 These authors contributed equally to the present work Correspondence: Dr Claudio Cabello-Verrugio (email claudio.cabello@unab.cl). common aspects of these diseases is the high level of circu- lating angiotensin II (AngII), the main peptide of the classical axis of the renin–angiotensin system (RAS). Recently, AngII has been demonstrated to be a key peptide in the regulation of skeletal muscle function by modulating tissue structure, dam- age and contractile activity in muscle diseases, such as in mus- cular dystrophy or insulin resistance [8–10]. In addition, sev- eral studies have described the effects of AngII as an atrophic factor in skeletal muscle [11,12]. One of the main mechanisms involved in the skeletal muscle atrophy induced by AngII is the C  The Authors Journal compilation C  2015 Biochemical Society 307 Clinical Science www.clinsci.org Au Au Aut C Copy aM ‡, Enrique Bra ad de Ciencias Biol ´ ogicas & ´ Cien gicas & Facultad y Envejecimiento (CARE), Laborator Univ a de C uthor C on ch n and n II (AngII) induce effects than AngII. sults show tha mius: the decrease in the fi MuRF-1. Ang-(1–7) also ind s shows that Ang-(1–7), d the increase in the exp ylation in myotub atrophic effects of A atrophy induced Our study indicat uscle wasting associated, at Au y wor angiotensin-(1–7), atrop UCTION CT