Noonan Syndrome (NS) is a relatively common congenital genetic condition characterized by congenital heart malformation, short stature, learning problems, indentation of the chest, impaired blood clotting, and a characteristic configuration of facial features.
In a study in mice appearing online on July 19 in advance of publication in the August print issue of the Journal of Clinical Investigation, Jeffrey Robbins and colleagues from Cincinnati Children?s Hospital Medical Center show that blocking the activation of the molecule ERK1/2 can prevent the development of NS-associated heart abnormalities.
Mutations in the protein SHP2 (Scr homology region 2, phosphatase 2) occur in approximately half of all NS patients with cardiac abnormalities. Robbins et al. used transgenic mice bred to express a mutated form of SHP2 in heart muscle cells during gestation or following birth. Embryonic hearts containing the mutated SHP2 had altered cardiomyocyte cell cycling and structural defects, while expression of the mutant protein in postnatal cardiomyocytes had no effect. Fetal expression of this mutated protein was found to activate the ERK1/2 pathway and further studies confirmed that activation by mutant SHP2 was necessary and sufficient to cause the heart abnormalities. The authors went on to show that prevention of ERK1/2 activation was able to prevent the development of cardiac abnormalities, suggesting that therapeutic modulation of ERK1/2 could be a useful strategy during embryonic development for preventing this form of congenital heart disease.
TITLE: Mediating ERK1/2 signaling rescues congenital heart defects in a mouse model of Noonan syndrome