Noonan syndrome-causing SHP2 mutants impair ERK-dependent chondrocyte differentiation during endochondral bone growth.
Mylène Tajan, Julie Pernin-Grandjean, Nicolas Beton, Isabelle Gennero, Florence Capilla, Benjamin G Neel, Toshiyuki Araki, Philippe Valet, Maithé Tauber, Jean-Pierre Salles, Armelle Yart, Thomas Edouard
Author Information
Mylène Tajan: INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC).
Julie Pernin-Grandjean: INSERM UMR 1043, Centre of Pathophysiology of Toulouse Purpan (CPTP), University of Toulouse Paul Sabatier, Toulouse, France.
Nicolas Beton: INSERM UMR 1043, Centre of Pathophysiology of Toulouse Purpan (CPTP), University of Toulouse Paul Sabatier, Toulouse, France.
Isabelle Gennero: INSERM UMR 1043, Centre of Pathophysiology of Toulouse Purpan (CPTP), University of Toulouse Paul Sabatier, Toulouse, France.
Florence Capilla: INSERM, US006, ANEXPLO/CREFRE, Histopathology Unit, Purpan Hospital, Toulouse, France.
Benjamin G Neel: Laura and Isaac Perlmutter Cancer Center, NYU-Langone Medical Center, NY 10016, USA.
Toshiyuki Araki: Laura and Isaac Perlmutter Cancer Center, NYU-Langone Medical Center, NY 10016, USA.
Philippe Valet: INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC).
Maithé Tauber: INSERM UMR 1043, Centre of Pathophysiology of Toulouse Purpan (CPTP), University of Toulouse Paul Sabatier, Toulouse, France.
Jean-Pierre Salles: INSERM UMR 1043, Centre of Pathophysiology of Toulouse Purpan (CPTP), University of Toulouse Paul Sabatier, Toulouse, France.
Armelle Yart: INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC).
Thomas Edouard: INSERM UMR 1043, Centre of Pathophysiology of Toulouse Purpan (CPTP), University of Toulouse Paul Sabatier, Toulouse, France.
Growth retardation is a constant feature of Noonan syndrome (NS) but its physiopathology remains poorly understood. We previously reported that hyperactive NS-causing SHP2 mutants impair the systemic production of insulin-like growth factor 1 (IGF1) through hyperactivation of the RAS/extracellular signal-regulated kinases (ERK) signalling pathway. Besides endocrine defects, a direct effect of these mutants on growth plate has not been explored, although recent studies have revealed an important physiological role for SHP2 in endochondral bone growth. We demonstrated that growth plate length was reduced in NS mice, mostly due to a shortening of the hypertrophic zone and to a lesser extent of the proliferating zone. These histological features were correlated with decreased expression of early chondrocyte differentiation markers, and with reduced alkaline phosphatase staining and activity, in NS murine primary chondrocytes. Although IGF1 treatment improved growth of NS mice, it did not fully reverse growth plate abnormalities, notably the decreased hypertrophic zone. In contrast, we documented a role of RAS/ERK hyperactivation at the growth plate level since 1) NS-causing SHP2 mutants enhance RAS/ERK activation in chondrocytes in vivo (NS mice) and in vitro (ATDC5 cells) and 2) inhibition of RAS/ERK hyperactivation by U0126 treatment alleviated growth plate abnormalities and enhanced chondrocyte differentiation. Similar effects were obtained by chronic treatment of NS mice with statins. In conclusion, we demonstrated that hyperactive NS-causing SHP2 mutants impair chondrocyte differentiation during endochondral bone growth through a local hyperactivation of the RAS/ERK signalling pathway, and that statin treatment may be a possible therapeutic approach in NS.
References
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