Developmental SHP2 dysfunction underlies cardiac hypertrophy in Noonan syndrome with multiple lentigines
Jessica Lauriol, … , Kyu-Ho Lee, Maria I. Kontaridis
Jessica Lauriol, … , Kyu-Ho Lee, Maria I. Kontaridis
Published August 1, 2016; First published June 27, 2016
Citation Information: J Clin Invest. 2016;126(8):2989-3005. https://doi.org/10.1172/JCI80396.
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Categories: Research Article Cardiology

Developmental SHP2 dysfunction underlies cardiac hypertrophy in Noonan syndrome with multiple lentigines

Abstract

Hypertrophic cardiomyopathy is a common cause of mortality in congenital heart disease (CHD). Many gene abnormalities are associated with cardiac hypertrophy, but their function in cardiac development is not well understood. Loss-of-function mutations in PTPN11, which encodes the protein tyrosine phosphatase (PTP) SHP2, are implicated in CHD and cause Noonan syndrome with multiple lentigines (NSML), a condition that often presents with cardiac hypertrophic defects. Here, we found that NSML-associated hypertrophy stems from aberrant signaling mechanisms originating in developing endocardium. Trabeculation and valvular hyperplasia were diminished in hearts of embryonic mice expressing a human NSML-associated variant of SHP2, and these defects were recapitulated in mice expressing NSML-associated SHP2 specifically in endothelial, but not myocardial or neural crest, cells. In contrast, mice with myocardial- but not endothelial-specific NSML SHP2 expression developed ventricular septal defects, suggesting that NSML-associated mutations have both cell-autonomous and nonautonomous functions in cardiac development. However, only endothelial-specific expression of NSML-associated SHP2 induced adult-onset cardiac hypertrophy. Further, embryos expressing the NSML-associated SHP2 mutation exhibited aberrant AKT activity and decreased downstream forkhead box P1 (FOXP1)/FGF and NOTCH1/EPHB2 signaling, indicating that SHP2 is required for regulating reciprocal crosstalk between developing endocardium and myocardium. Together, our data provide functional and disease-based evidence that aberrant SHP2 signaling during cardiac development leads to CHD and adult-onset heart hypertrophy.

Authors

Jessica Lauriol, Janel R. Cabrera, Ashbeel Roy, Kimberly Keith, Sara M. Hough, Federico Damilano, Bonnie Wang, Gabriel C. Segarra, Meaghan E. Flessa, Lauren E. Miller, Saumya Das, Roderick Bronson, Kyu-Ho Lee, Maria I. Kontaridis

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Figure 6

NSML expression affects both apoptosis and proliferation in the developing heart.

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NSML expression affects both apoptosis and proliferation in the developi...
(A) Immunofluorescence staining of E14.5 embryo hearts representative of endocardial cell apoptosis and proliferation using Apoptag (top panels) to mark apoptotic cells (red) or p-HH3 (lower panels) to mark proliferation (red). Additional double-staining for MF20 was used to identify myocardium (green), and Hoechst stain was used to mark the nuclei, and in this case, to delineate the mitral valves. Scale bars: 50 μm. Quantification of endocardial (B) apoptosis and (C) proliferation is demonstrated from n = 4 embryos per group per analysis, with counts equal to or greater than 1000 cells/embryo/defined area. (D) Immunofluorescence staining of myocardial cell apoptosis and proliferation using Apoptag (upper panels) to mark apoptotic cells (red) or p-HH3 (lower panels) to mark proliferation (red) in left ventricle or right ventricle. Additional double-staining for MF20 was used to identify myocardium (green), and Hoechst stain was used to mark the nuclei. Scale bars: 50 μm. p-HH3, phospho-histone H3. Quantification of myocardial (E) apoptosis and (F) proliferation are demonstrated in left ventricle, right ventricle, septum, and total myocardium, with n = 4 embryos per group per analysis, with counts equal to or greater than 1000 cells/embryo/defined area. All data are expressed as mean ± SEM. *P < 0.05; **P < 0.01. P values were derived from 1-way ANOVA with Bonferroni’s post-test when ANOVA was significant.