title: Deoxyribozyme-mediated knockdown of xylosyltransferase-1 mRNA promotes axon growth in the adult rat spinal cord.
abstract: In the injured spinal cord, proteoglycans (PGs) within scar tissue obstruct axon growth through their glycosaminoglycan (GAG)-side chains. The formation of GAG-side chains (glycosylation) is catalysed by xylosyltransferase-1 (XT-1). Here, we knocked down XT-1 mRNA using a tailored deoxyribozyme (DNAXTas) and hypothesized that this would decrease the amount of glycosylated PGs and, consequently, promote axon growth in the adult rat spinal cord. A continuous 2-week delivery of DNAXTas near the rostral border of a peripheral nerve graft bridging the transected dorsal columns in the thoracic spinal cord resulted in an 81% decrease in XT-1 mRNA, an average of 1.4-fold reduction in GAG-side chains of chondroitin sulphate or heparan sulphate-PGs and 2.2-fold reduction in neurocan and brevican core proteins in scar tissue. Additionally, compared to control deoxyribozyme, the DNAXTas treatment resulted in a 9-fold increase in length and a 4-fold increase in density of ascending axons growing through the nerve graft and scar tissue present at the rostral spinal cord. Together our data showed that treatment with a deoxyribozyme against XT-1 mRNA decreased the amount of glycosylated PGs and promoted axon growth through scar tissue in the injured spinal cord. The deoxyribozyme approach may become a contributing factor in spinal cord repair strategies.
authors.affiliation: International Center for Spinal Cord Injury, Hugo W Moser Research Institute at Kennedy Krieger, Baltimore, MD, USA.
authors.forename: Andres
authors.initials: A
authors.lastname: Hurtado
authors.forename: Heidrun
authors.initials: H
authors.lastname: Podinin
authors.forename: Martin
authors.initials: M
authors.lastname: Oudega
authors.forename: Barbara
authors.initials: B
authors.lastname: Grimpe