Molecular Architecture of the Blood Brain Barrier Tight Junction Proteins--A Synergistic Computational and In Vitro Approach.

The blood-brain barrier (BBB) constituted by claudin-5 tight junctions is critical in maintaining the homeostasis of the central nervous system, but this highly selective molecular interface is an impediment for therapeutic interventions in neurodegenerative and neurological diseases. Therapeutic strategies that can exploit the paracellular transport remain elusive due to lack of molecular insights of the tight junction assembly. This study focuses on analyzing the membrane driven cis interactions of claudin-5 proteins in the formation of the BBB tight junctions. We have adopted a synergistic approach employing in silico multiscale dynamics and in vitro cross-linking experiments to study the claudin-5 interactions. Long time scale simulations of claudin-5 monomers, in seven different lipid compositions, show formation of cis dimers that subsequently aggregate into strands. In vitro formaldehyde cross-linking studies also conclusively show that cis-interacting claudin-5 dimers cross-link with short methyle...