Paolo Grieco, Ciro Indolfi, Francesco Borgia, Massimo Chiariello, Luigi Di Serafino, Cinzia Perrino, Giovanni Esposito, Giuseppe Gargiulo, Laura Scudiero, Gianluigi Pironti, Alessandro Cannavo, Anna Franzone, Gabriele G. Schiattarella, Anna Sannino, Esposito, Giovanni, Perrino, Cinzia, Cannavo, A, Schiattarella, Gg, Borgia, Francesco, Sannino, A, Pironti, G, Gargiulo, G, Di Serafino, L, Franzone, A, Scudiero, L, Grieco, Paolo, Indolfi, C, and Chiariello, Massimo
Urotensin II (UTII) and its seven trans-membrane receptor (UTR) are up-regulated in the heart under pathological conditions. Previous in vitro studies have shown that UTII trans-activates the epidermal growth factor receptor (EGFR), however, the role of such novel signalling pathway stimulated by UTII is currently unknown. In this study, we hypothesized that EGFR trans-activation by UTII might exert a protective effect in the overloaded heart. To test this hypothesis, we induced cardiac hypertrophy by transverse aortic constriction (TAC) in wild-type mice, and tested the effects of the UTII antagonist Urantide (UR) on cardiac function, structure, and EGFR trans-activation. After 7 days of pressure overload, UR treatment induced a rapid and significant impairment of cardiac function compared to vehicle. In UR-treated TAC mice, cardiac dysfunction was associated with reduced phosphorylation levels of the EGFR and extracellular-regulated kinase (ERK), increased apoptotic cell death and fibrosis. In vitro UTR stimulation induced membrane translocation of beta-arrestin 1/2, EGFR phosphorylation/internalization, and ERK activation in HEK293 cells. Furthermore, UTII administration lowered apoptotic cell death induced by serum deprivation, as shown by reduced TUNEL/Annexin V staining and caspase 3 activation. Interestingly, UTII-mediated EGFR trans-activation could be prevented by UR treatment or knockdown of beta-arrestin 1/2. Our data show, for the first time in vivo, a new UTR signalling pathway which is mediated by EGFR trans-activation, dependent by beta-arrestin 1/2, promoting cell survival and cardioprotection.