Coxsackievirus-adenovirus receptor (CAR) is essential for early embryonic cardiac development

Abstract

The coxsackievirus-adenovirus receptor (CAR) is a cell contact protein on various cell types with unknown physiological function. It belongs to a subfamily of the immunoglobulin-superfamily of which some members are junctional adhesion molecules on epithelial and/or endothelial cells. CAR is dominantly expressed in the hearts and brains of mice until the newborne phase after which it becomes mainly restricted to various epithelial cells. To understand more about the physiological function of CAR, we have generated CAR-deficient mice by gene targeting. We found that these mice die between E11.5 and E13.5 of embryonal development. Ultrastructural analysis of cardiomyocytes revealed that the density of myofibrils was reduced and that their orientation and bundling was disorganized. In addition, mitochondria were enlarged and glycogen storage strongly enriched. In line with these defects, we observed pericardial edema formation as a clear sign of insufficient heart function. Developmental abnormalities likely to be secondary effects of gene ablation were the persistent singular cardial atrio-ventricular canal and dilatations of larger blood vessels such as the cardinal veins. The secondary nature of these defects was supported by the fact that CAR was not expressed on vascular cells or on cells of the vascular wall. No obvious signs for alterations of the histological organization of the placenta were observed. We conclude that CAR is required for embryonal heart development, most likely due to its function during the organization of myofibrils in cardiomyocytes.

CAR might provide a survival signal for myocardial cells

“…We read with great interest the Research Article by Dorner et al (Dorner et al, 2005) describing their coxsackievirus and adenovirus receptor (CAR)-deficient mouse, as we have previously published details of our own CAR-knockout mouse (Asher et al, 2005). Our findings of embryonic death associated with cardiac defects at day 11.5 postconception were very similar to theirs.…”

The Coxsackievirus–Adenovirus Receptor Reveals Complex Homophilic and Heterophilic Interactions on Neural Cells

“…In the adult heart, CAR is predominantly localized at the intercalated discs (Shaw et al, 2004). In the vertebrate nervous system, CAR is strongly expressed during embryogenesis, followed by drastic reduction at early postnatal stages (Xu and Crowell, 1996;Honda et al, 2000;Dorner et al, 2005).…”

“…The absence of CAR in mice results in lethality at embryonic day 11 because of malformations of the heart (Asher et al, 2005;Dorner et al, 2005;Chen et al, 2006). In the adult heart, ablation of CAR results in disturbed conduction of electrical activity from the atrium (A) to the ventricle (V) as indicated by a prolonged PR interval in electrocardiogram plots.…”

Profiling Subcellular Protein Phosphatase Responses to Coxsackievirus B3 Infection of Cardiomyocytes

“…diomyocytes (93,94), CVB3 pathogenesis is largely studied in permissive HeLa cells because of the efficiency of viral propagation (40,95,96). As an alternative, neonatal mouse HL-1 cells have been used (35,39), but these cells are atrially derived, and CVB3 infections disproportionately impact the ventricular myocardium (97,98).…”