Obestatin/GPR39 signaling stimulates skeletal muscle repair by inducing the expansion of satellite stem cells as well as myofiber hypertrophy. Here, we describe that the obestatin/GPR39 system acts as autocrine/paracrine factor on human myogenesis. Obestatin regulated multiple steps of myogenesis: myoblast proliferation, cell cycle exit, differentiation and recruitment to fuse and form multinucleated hypertrophic myotubes. Obestatin-induced mitogenic action was mediated by ERK1/2 and JunD activity, being orchestrated by a G-dependent mechanism. At a later stage of myogenesis, scaffolding proteins β-arrestin 1 and 2 were essential for the activation of cell cycle exit and differentiation through the transactivation of the epidermal growth factor receptor (EGFR). Upon obestatin stimulus, β-arrestins are recruited to the membrane, where they functionally interact with GPR39 leading to Src activation and signalplex formation to EGFR transactivation by matrix metalloproteinases. This signalplex regulated the mitotic arrest by p21 and p57 expression and the mid- to late stages of differentiation through JNK/c-Jun, CAMKII, Akt and p38 pathways. This finding not only provides the first functional activity for β-arrestins in myogenesis but also identify potential targets for therapeutic approaches by triggering specific signaling arms of the GPR39 signaling involved in myogenesis.

Dyeing with cochineal extract has been carried out in Mexico since pre‐Hispanic times as a handcraft process. However, this has limited its application on fabrics other than wool. An experiment was designed to study the influence of mordant concentration on colour behaviour in cotton fabric dyed with cochineal extract at the laboratory. At the same time, colour fastness was determined by applying six fastness tests to define the quality of the dyed fabric. It was concluded that, when there was a larger concentration of metallic ions in the mordant, colour fixation in the fabric was better, as there was less lightness in the red hue of the fabric. In addition, the more hydrogen ions present because of acids, the more intense the red hue. A decreasing trend in the colour fastness tests was observed: dry rubbing > artificial light > acids > alkalis > domestic washing > hot water.