Dr. Antonio Martins

Institution: UPR – Medical Sciences Campus

Email: antonio.martins@upr.edu

Identification of the molecular mechanisms of the blood-brain barrier disruption by the NG291 peptide

The blood-brain barrier (BBB) is a specialized barrier that impedes the flow of substances from the  blood to the central nervous system. What blocks the free flow of substances are highly specialized blood microvessels different from those on the peripheral system. The vessels on the CNS display specialized tight junctions for (paracellular transport) and transcellular vesicular transport (transcytosis). This selectivity of transport is so powerful that it prevents the uptake of pharmaceuticals, creating one of the biggest challenges in treating the central nervous system. One strategy to transiently increase the BBB permeability includes activating the B2 kinin receptor (B2BR) by protease-resistant agonists such as NG291. B2R is a G protein-coupled receptor and an essential effector of the kallikreinkinin system, widely expressed in astrocytes and endothelial cells forming the BBB. Our recent discoveries found that we can safely open the BBB using NG291 and the type of disrupted transport is dose dependent. However, a limited understanding of the molecular pathways that control these transports through the BBB after activation of B2BKR by NG291 has decreased our capability of manipulating the normal BBB. Therefore, we will fill this gap of knowledge. We aim to elucidate the NG291 molecular pathway in two different BBB transport systems, paracellular and transcytosis. First, we will investigate the molecular mechanisms triggered by NG291 that disrupt the paracellular mechanism. Using inhibitors of key proteins of different pathways, western blot, and radiolabeled probes, we aim to identify the differentially expressed protein in tight junctions to evaluate changes in paracellular transport. Second, we will investigate the molecular pathways of transcytosis modified by NG291 using molecular strategies, western blot, radiolabeled probes, and transmission electron microscopy. The experiments described here represent complementation of previous results and expand the research to improve the penetration of drugs that cannot cross the blood-brain barrier. Finally, attaining the goals delineated here, we can produce a significant impact on neurosciences, enabling physicians to open for a short period and exclusively a desired type of transport for the transient delivery of drugs to the CNS.