Transcriptional deregulation and a missense mutation define ANKRD1 as a candidate gene for total anomalous pulmonary venous return

Abstract

Total anomalous pulmonary venous return (TAPVR) is a congenital heart defect in which the pulmonary veins fail to enter the left atrium and drain instead into the right atrium or one of its venous tributaries. Although a genetic basis for TAPVR has long been recognized, no single gene involved in the pathogenesis of this disease has been identified to date. We previously reported a TAPVR patient bearing a de novo 10;21 balanced translocation. In this work, we cloned both translocation breakpoints from this patient and mapped the ANKRD1 gene, encoding a cardiac transcriptional regulator, 130 kb proximally to the breakpoint on chromosome 10. In situ hybridization analysis performed on murine embryos showed ANKRD1 expression in the developing pulmonary veins, suggesting a possible role for this gene in TAPVR pathogenesis. Moreover, ANKRD1 expression levels were found to be highly increased in lymphoblastoid cell lines derived from both the translocation-bearing proband and a second independent sporadic TAPVR patient, suggesting that disruption of the normal ANKRD1 expression pattern is associated with TAPVR. Finally, a nonconservative missense mutation in the ANKRD1 gene was found in a third sporadic TAPVR patient. In vitro calpain-mediated degradation assays, coupled to reporter gene analysis in transfected HeLa cells, strongly suggested that this mutation enhances both the stability of the ANKRD1/CARP protein and its transcriptional repression activity upon the cardiac-specific atrial natriuretic factor (ANF) promoter. Taken together, these results define ANKRD1 as a possible candidate gene for TAPVR pathogenesis.

Differential Regulation of Transforming Growth Factor β Signaling Pathways by Notch in Human Endothelial Cells

“…Additionally, we have found that ANKRD1, a TGF␤/Smad3 target in smooth muscle cells (33), was synergistically induced by Notch activation and TGF␤ signaling in endothelial cells. Interestingly, the association between the disruption of ANKRD1 expression and the pathogenesis of total anomalous pulmonary venous return (TAPVR), a congenital heart defect, has also been suggested in a recent study (48). Here we show that endothelium-specific inhibition of Notch activity by the overexpression of dnMAML1 in vivo blocks EndMT and reduces Smad3 expression in cardiac cushion cells of mouse embryonic hearts, and this impingement of Notch on a second distinct signaling pathway may explain the severe cardiac defects seen in targeted Notch1 mutants (6).…”

The enigmatic role of the ankyrin repeat domain 1 gene in heart development and disease

“…Later, ANKRD1/CARP expression has been found to be rapidly induced in cardiomyocytes in response to hypertrophy stimuli, as well as, at heart failure (HF), suggesting an involvement of ankrd1 activities in physiological and pathological remodeling of ventricular myocardium (Aihara et al, 2000;Zolk et al, 2002;Nagueh et al, 2004). Recently, ankrd1 has been identified as a candidate gene that can play a role in congenital heart disease (Cinquetti et al, 2008).…”

Intron retention generates ANKRD1 splice variants that are co-regulated with the main transcript in normal and failing myocardium

“…In addition, ankrd1 has also been identified as a candidate gene that can play an important role in congenital cardiac (Cinquetti et al, 2008) and skeletal muscle (Bakay et al, 2002;Nakada et al, 2003) disease, as well as in angiogenesis (Boengler et al, 2003), neovascularization (Shi et al, 2005;Samaras et al, 2007) and neurite outgrowth (Stam et al, 2007). In in vivo experimental settings, ANKRD1 is used as a surrogate biomarker of cardiac hypertrophy (Aihara et al, 2000), cardio-toxic damage (Torrado et al, 2004) or skeletal myopathy (Casey et al, 2008).…”