Large-scale chondroitin sulfate proteoglycan digestion with chondroitinase gene therapy leads to reduced pathology and modulates macrophage phenotype following spinal cord contusion injury.
journal contributionposted on 14.05.2019, 14:23 by K Bartus, ND James, A Didangelos, KD Bosch, J Verhaagen, RJ Yáñez-Muñoz, JH Rogers, BL Schneider, EM Muir, EJ Bradbury
Chondroitin sulfate proteoglycans (CSPGs) inhibit repair following spinal cord injury. Here we use mammalian-compatible engineered chondroitinase ABC (ChABC) delivered via lentiviral vector (LV-ChABC) to explore the consequences of large-scale CSPG digestion for spinal cord repair. We demonstrate significantly reduced secondary injury pathology in adult rats following spinal contusion injury and LV-ChABC treatment, with reduced cavitation and enhanced preservation of spinal neurons and axons at 12 weeks postinjury, compared with control (LV-GFP)-treated animals. To understand these neuroprotective effects, we investigated early inflammatory changes following LV-ChABC treatment. Increased expression of the phagocytic macrophage marker CD68 at 3 d postinjury was followed by increased CD206 expression at 2 weeks, indicating that large-scale CSPG digestion can alter macrophage phenotype to favor alternatively activated M2 macrophages. Accordingly, ChABC treatment in vitro induced a significant increase in CD206 expression in unpolarized monocytes stimulated with conditioned medium from spinal-injured tissue explants. LV-ChABC also promoted the remodelling of specific CSPGs as well as enhanced vascularity, which was closely associated with CD206-positive macrophages. Neuroprotective effects of LV-ChABC corresponded with improved sensorimotor function, evident as early as 1 week postinjury, a time point when increased neuronal survival correlated with reduced apoptosis. Improved function was maintained into chronic injury stages, where improved axonal conduction and increased serotonergic innervation were also observed. Thus, we demonstrate that ChABC gene therapy can modulate secondary injury processes, with neuroprotective effects that lead to long-term improved functional outcome and reveal novel mechanistic evidence that modulation of macrophage phenotype may underlie these effects.
This work was supported by the United Kingdom Medical Research Council (Senior Non-Clinical Fellowship Award G1002055), the International Spinal Research Trust (SRT101), the Henry Smith Charity, the Darwin Trust of Edinburgh, and the International Foundation for Research in Paraplegia (to E.J.B.); the International Spinal Research Trust (TR1002 to E.M.M.); and European Union FP7 projects Plasticise (Project Number 223524, to B.L.S.) and Persist (222878, to R.J.Y.-M.).
CitationJournal of Neuroscience, 2014, 34 (14), pp. 4822-4836
Author affiliation/Organisation/COLLEGE OF LIFE SCIENCES/School of Medicine/Department of Infection, Immunity and Inflammation
VersionVoR (Version of Record)
Published inJournal of Neuroscience
PublisherSociety for Neuroscience
chondroitinasecontusiongene therapyneuroprotectionspinal cord injuryAnimalsCells, CulturedChondroitin ABC LyaseChondroitin Sulfate ProteoglycansDisease Models, AnimalElectric StimulationFemaleGene Expression RegulationGenetic TherapyInjections, SpinalMacrophagesNerve Tissue ProteinsNeural ConductionPsychomotor PerformanceRatsRats, Sprague-DawleySpinal Cord InjuriesTime Factors