Li, W.; McCurdy, S.; Lopez-Ramirez, M. A.; Lee, H.-S.

Propranolol reduces experimental murine cerebral cavernous malformations (CCMs) and prevents embryonic caudal venous plexus (CVP) lesions in zebrafish that follow mosaic inactivation of ccm2. Because morpholino silencing of the {beta}1 adrenergic receptor (adrb1) prevents the embryonic CVP lesion, we proposed that adrb1 plays a role in CCM pathogenesis. Here we report that adrb1-/- zebrafish exhibited 86.80% fewer CVP lesions and 87.34% reduction of CCM lesion volume relative to wild type brood mates at 2dpf and 8-10 weeks stage, respectively. Treatment with metoprolol, a beta1 selective antagonist, yielded a similar reduction in CCM lesion volume. Adrb1-/- 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 beta1 receptor antagonism.