Genetic inactivation of the β1 adrenergic receptor prevents cerebral cavernous malformations in zebrafish.

Abstract

Previously, we showed that propranolol reduces experimental murine cerebral cavernous malformations (CCMs) and prevents embryonic caudal venous plexus (CVP) lesions in zebrafish that follow mosaic inactivation of <i>ccm2</i> (Li et al., 2021). Because morpholino silencing of the β1 adrenergic receptor (<i>adrb1</i>) prevents the embryonic CVP lesion, we proposed that <i>adrb1</i> plays a role in CCM pathogenesis. Here, we report that <i>adrb1^-/-</i> zebrafish exhibited 86% fewer CVP lesions and 87% reduction of CCM lesion volume relative to wild type brood mates at 2dpf and 8-10 weeks stage, respectively. Treatment with metoprolol, a β1 selective antagonist, yielded a similar reduction in CCM lesion volume. <i>Adrb1^-/-</i> zebrafish embryos exhibited reduced heart rate and contractility and reduced CVP blood flow. Similarly, slowing the heart and eliminating the blood flow in CVP by administration of 2,3-BDM suppressed the CVP lesion. In sum, our findings provide genetic and pharmacological evidence that the therapeutic effect of propranolol on CCM is achieved through β1 receptor antagonism.