Journal international de recherche cardiovasculaire

Cardiac Malformations in EMILIN2 Deficient Mice

Anuradha Guggilam, Devaraja Sannaningaiah, Yanqing Gong, Jessica Grondolsky, Menggui Huang, Huigin Nie,Elaine C Davis, Yehe Liu, Michael Jenkins, James Strainic and Jane Hoover-Plow

Background: EMILIN2, elastin microfibril interface located protein 2, is expressed during cardiovascular development, by cardiac stem cells, and in adult animal models of heart disease. In humans, the EMILIN2 gene is located on the short arm of Chromosome 18, and patients with partial or complete deletions of this chromosome region have cardiac malformations. The objective of this study was to evaluate whether the Emilin2 deficient mice have cardiac defects. Methods and results: Cardiac malformations were assessed in adult Emilin2, Emilin1 (EMILIN2 homologue) deficient mice, and Emilin2:Emilin1 double deficient mice. The primary malformation in Emilin2 deficient mice was ventricular septal defects. Although EMILIN1, is also expressed during cardiovascular development,the primary cardiac anomalies in Emilin1 deficient mice were valve insufficiency (pulmonary, aortic and mitral). Only half of the expected Emilin2:Emilin1 double deficient offspring were weaned, indicating embryonic and perinatal lethality. Surviving Emilin2:Emilin1 double deficient mice had both ventricular septal defects and regurgitation of valves. There was a trend for anterior wall thinning and left ventricular dilation in Emilin2:Emilin1 double deficient mice. In embryonic Emilin2:Emilin1 double deficient mice complete arterioventricular canal defects and ventricular septal defects were identified. A potential mechanism for development of cardiac defects in Emilin2 deficiency may be reduced mobilization of stem cells during heart development. Conclusions: Emilin2 deficient mice express cardiac anomalies, primarily ventricular septal defects, and Emilin1 mice exhibit primarily valve abnormalities including pulmonary regurgitation, whereas in Emilin2: Emilin1 double deficient mice, both anomalies occurred, suggesting that Emilin2 and Emilin1 have differential roles in cardiac development. Emilin2 deficient mice have cardiac malformations similar to individuals with deletions of the short arm of Chromosome 18. Emilin2 deficient mice may be an informative model to investigate the consequences of cardiac anomalies in subjects with deletions of the short arm of Chromosome 18, 18p