97 - The Role of DVL2 in Congenital Heart Disease

Poster Number: 97
Publication Number: 97.425

Alyx Posorske, Riley Hospital for Children at Indiana University Health, Indianapolis, IN, United States; Matthew Durbin, Indiana University School of Medicine, Indianapolis, IN, United States; Laura Haneline, Indiana University School of Medicine, Indianapolis, IN, United States; Nina J. Jain, University of California, Davis, Carmel, IN, United States; Ellen V. Voskoboynik, Indiana University School of Medicine, Indianapolis, IN, United States; James B. Zwierzynski, Indiana University School of Medicine, Indianapolis, IN, United States; Weinian Shou, Indiana University School of Medicine, Indianapolis, IN, United States; Stephanie M. Ware, Indiana University School of Medicine, Indianapolis, IN, United States

Background: Congenital heart defects (CHDs) are the most common birth defects, yet most etiologies remain unknown. DISHEVELLED2 (DVL2) is a protein whose loss-of-function is implicated in CHD. DVL2 is thought to have a role driving second heart field (SHF) and cardiac neural crest cells (NC) migration during cardiac development.  A recent study demonstrates DVL2 is bimodally regulated by two other proteins, DAAM1 and VANGL2, during neurulation. This process is unexplored in cardiac development and has important implications for CHD pathogenesis in humans. 

Objective: We hypothesize DVL2 is critical in cardiac development by its genetic interaction with DAAM1 and VANGL2, and by its involvement in SHF and NC cell migration, and disruption of these processes leads to CHD. 

Design/Methods: To determine mechanisms by which DVL2 loss-of-function leads to cardiac defects, we performed analysis of the transcriptome, proteome and kinome in DVL2∆/∆ and littermate DVL2+/+  embryos at E12.5 during closure of the ventricular septum. We performed RNA-seq analysis in micro-dissected LV and OFT, and also after conditional deletion of OFT NC (Wnt1-Cre) and SHF cells (Mef2c-Cre). We performed TMT-MS analysis of the global and phosphor-proteome of these genetically manipulated mouse embryonic hearts. We compared differential expression profiles and further implemented pathway analysis. We also crossed heterozygous loss-of-function mice (DVL2+/∆, DAAM1+/gt,  VANGL2+/∆) to generate cohort litters of embryos haploinsufficient for one, two, or all three proteins, and performed histologic analysis at E14.5 to identify anatomic cardiac defects. 

Results: Deletion of DVL2 in the LV and in the SHF of the OFT revealed no differentially expressed genes, but deletion of OFT NC reveals 115 genes were significantly altered (FDR< 0.05), indicating a likely role in NC migration to the OFT. Global proteome and kinome analysis revealed 179 and 33 differentially expressed proteins, respectively, (p< 0.05). Differential expression and pathway analysis revealed multiple genes, proteins and pathways important for cardiac development. Preliminary analysis reveals a trend of increased membranous VSDs within the compound heterozygous embryos, with VSDs in 4 of 10, (40%) of DVL2+/∆, DAAM1+/gt, VANGL2+/∆ embryos, compared to 2 of 14, (14%) in single heterozygous embryos.

Conclusion(s): Our data suggests DVL2 has a role in NC migration, and it interacts with VANGL2 and DAAM1 during cardiac development. These unique mechanistic insights have important implications for CHD inheritance, pathogenesis and therapeutic development in humans.