Objective:

We aimed to verify a novel strategy of blood-brain barrier (BBB)-crossing delivery system for antisense oligonucleotide (ASO) by modulating the tricellular tight junctions (TJ) formed by brain microvascular endothelial cells.

Background:

ASO has increasingly become powerful therapeutic tools for intractable diseases. However, in case of treating disorders in the central nervous system, safe yet efficient methods of delivering ASO across the BBB by systemic administration have not been established. Recently, molecular characteristics of tricellular TJ located at the point where three cells meet in the BBB have been gradually elucidated.

Design/Methods:

We prepared angubindin-1, a recombinant protein fragment that binds to and modulates angulin-1 expressed at the TJs in the BBB, by using an E.coli expression system. Then we intravenously injected angubindin-1 and subsequently fluorescent-labeled ASO to mice, and examined the distribution of the ASO in the brain by immunohistochemical analyses. We also evaluated the effect of intravenously injected angubindin-1 on the silencing effect of the target RNA in the brain and spinal cord by subsequently injected ASO.

Results:

The fluorescent signals of the ASO were apparent in neurons when injected after angubindin-1. Prior administration of angubindin-1 produced a silencing effect of ASO by 30% to 40% in the brain and spinal cord. This silencing effect was dependent on the interval of injection between angubindin-1 and ASO, and was increased in a dose-dependent manner of both angubindin-1 and ASO. We also found that similarly prepared bicellular TJ modulators did not produce such a silencing effect.

Conclusions:

The delivery strategy of modulating the tricellular TJ in the BBB via angubindin-1 provides a novel avenue of development of ASO-based therapeutics for the treatment of various disorders in the central nervous system.