In vivo discovery of blood-brain barrier opening small molecules with FishNAP

Abstract

The blood-brain barrier (BBB) maintains neural homeostasis by tightly regulating molecular exchange between the circulation and the brain, but it also restricts drug delivery and thereby limits treatment of neurological disorders. Pharmacological agents that transiently and safely increase BBB permeability could therefore improve brain drug delivery, yet their systematic discovery has been constrained by the limitations of existing approaches. Here we present FishNAP, a non-invasive, high-throughput zebrafish platform for real-time in vivo assessment of BBB permeability. Screening 2,320 FDA-approved small molecules identified seven that increased BBB permeability in zebrafish, with barrier integrity recovering within 24 hours in each case, indicating reversible modulation. Three of these compounds, Calcitriol, Lovastatin and Sunitinib, which act through distinct signaling pathways, also increased BBB permeability in adult mice through both tight junction disruption and increased transcytosis. FishNAP thus enables the identification of conserved modulators of BBB function with translational potential for brain drug delivery.