A Nanomule Peptide Carrier Delivers siRNA Across the Intact Blood-Brain Barrier to Attenuate Ischemic Stroke

Abstract

The blood-brain barrier (BBB) hinders the distribution of therapeutics intended for treatment of neuroinflammation (NI) of the central nervous system. A twelve-amino acid peptide that transcytoses the BBB, termed MTfp, was chemically conjugated to siRNA to create a novel peptide-oligonucleotide conjugate (POC), directed to downregulate NOX4, a gene thought responsible for oxidative stress in ischemic stroke. The MTfp-NOX4 POC has the ability to cross the intact BBB and knockdown NOX4 expression in the brain. Following induction of ischemic stroke, animals pretreated with the POC exhibited significantly smaller infarcts; accompanied by increased protection against neurological deterioration and improved recovery. The data demonstrates that the MTfp can act as a nanomule to facilitate BBB transcytosis of siRNAs; where the NOX-4 specific siRNA moiety can elicit effective therapeutic knockdown of a gene responsible for oxidative stress in the central nervous system. This study is the first to conclusively demonstrate both siRNA-carrier delivery and therapeutic efficacy in any CNS disease model where the BBB remains intact and thus offers new avenues for potential treatments of oxidative stress underlying neuroinflammation in a variety of neuropathologies that are currently refractory to existing therapies.

RNA-based therapeutics for neurological diseases

“…Another BBB-crossing siRNA technology, the XB 3 platform developed by Bioasis works via peptide conjugation (a 12 amino acid peptide called MTfp) and receptor-mediated transcytosis. Proof-of-concept has been obtained for the silencing of NOX4 which plays a role in ischaemic stroke [ 111 ]. After induction of ischaemic stroke, animals treated with this novel siRNA suffered significantly reduced infarcts and improved recovery [ 111 ].…”

“…Proof-of-concept has been obtained for the silencing of NOX4 which plays a role in ischaemic stroke [ 111 ]. After induction of ischaemic stroke, animals treated with this novel siRNA suffered significantly reduced infarcts and improved recovery [ 111 ].…”

Liver-directed gene therapy corrects neurologic disease in a murine model of mucopolysaccharidosis type I-Hurler

“…17 In addition, MTfp effectively delivered NOX4-specific small interfering RNA (siRNA) to the brain, reducing ischemic stroke. 18 These studies indicate that MTfp, as a brain-targeting peptide, has the potential to facilitate drug delivery to the brain.…”

Oxidative Injury in Ischemic Stroke: A Focus on NADPH Oxidase 4

“…It could be a feasible way to reduce the expression of NOX4 by using NOX4-specific siRNA. It has been demonstrated that a twelve-amino acid peptide (MTfp), derived from melanotransferrin (MTf), could efficiently transport siRNA through the BBB model by forming a novel peptide-oligonucleotide conjugate (POC) [ 106 , 107 ]. MTfp-NOX4 POC further reduced the expression level of NOX4.…”