Adenoviral vector carrying glial cell-derived neurotrophic factor for direct gene therapy in comparison with human umbilical cord blood cell-mediated therapy of spinal cord injury in rat

Abstract

Study design: Experimental study. Objective: To evaluate the treatment of spinal cord injury with glial cell-derived neurotrophic factor (GDNF) delivered using an adenoviral vector (AdV-GDNF group) in comparison with treatment performed using human umbilical cord blood mononuclear cells (UCB-MCs)-transduced with an adenoviral vector carrying the GDNF gene (UCB-MCs+AdV-GDNF group) in rat. Setting: Kazan, Russian Federation. Methods: We examined the efficacy of AdV-GDNF and UCB-MCs+AdV-GDNF therapy by conducting behavioral tests on the animals and morphometric studies on the spinal cord, performing immunofluorescence analyses on glial cells, investigating the survival and migration potential of UCB-MCs, and evaluating the expression of the recombinant GDNF gene. Results: At the 30th postoperative day, equal positive locomotor recovery was observed after both direct and cell-based GDNF therapy. However, after UCB-MCs-mediated GDNF therapy, the area of preserved tissue and the number of spared myelinated fibers were higher than those measured after direct GDNF gene therapy. Moreover, we observed distinct changes in the populations of glial cells; expression patterns of the specific markers for astrocytes (GFAP, S100B and AQP4), oligodendrocytes (PDGFαR and Cx47) and Schwann cells (P0) differed in various areas of the spinal cord of rats treated with AdV-GDNF and UCB-MCs+AdV-GDNF. Conclusion: The differences detected in the AdV-GDNF and UCB-MCs+AdV-GDNF groups could be partially explained by the action of UCB-MCs. We discuss the insufficiency and the advantages of these two methods of GDNF gene delivery into the spinal cord after traumatic injury. INTRODUCTIONSpinal cord injury (SCI) leads to complex pathological changes that include the death of neurons and glial cells and the demyelination and degeneration of nerve fibers. The limited growth capacity of mature central nervous system (CNS) neurons and the non-permissive environment of the CNS for axon regrowth are the main factors responsible for the little or no regeneration toward targets displayed by injured axons and for the permanent functional deficit observed after SCI. One promising approach for preventing neurodegeneration involves locally treating the site of injury in order to increase the expression of neurotrophic factors. Exploiting the stimulatory effects of neurotrophic factors on neuroregeneration appears to also be useful for SCI treatment, and one neurotrophic factor that is particularly suitable for SCI treatment is glial cell-derived neurotrophic factor (GDNF). GDNF is a member of the TGF-β superfamily that binds to the receptor GFRα1 and upregulates several signaling pathways; these pathways include those involving intracellular RAS/extracellular signalregulated kinase, phosphatidylinositol 3-kinase/AKT, p38 mitogen-

Mesenchymal Stem Cell Therapy for Spinal Cord Contusion: A Comparative Study on Small and Large Animal Models

“…Experimental approaches for the treatment of SCI have been evolving and currently include a variety of approaches with a significant prevalence of genetic [43][44][45] and cellular therapies. Cells of adult organism, embryonic cells, and induced pluripotent stem cells have been used in multiple studies with variable effects [46][47][48], as has the application of extracellular vesicles as a cell-free therapy [49].…”

Electrophysiological, Morphological, and Ultrastructural Features of the Injured Spinal Cord Tissue after Transplantation of Human Umbilical Cord Blood Mononuclear Cells Genetically Modified with the VEGF and GDNF Genes

“…Thus far, we have shown that transplantation of hUCB-MCs, transduced with Ad5-GDNF, into the area of SCI damage improves tissue preservation, reduces the formation of cavities, and inhibits degeneration of myelinated fibers [8, 28]. It is unclear, however, how transplantation of hUCB-MCs transduced with Ad5-VEGF alone functions in the same experimental model of SCI.…”

“…After skin incision, the Th8 vertebral level was removed by laminectomy. The impact rod (diameter 2 mm, 10 g) of an impactor was centered above Th8 and dropped from a height of 25 mm to induce SCI [8]. After SCI, cells were injected in the hUCB-MC groups; then the dorsal back musculature and skin were sutured.…”

“…Transplantation into the SCI of genetically modified by NT-3 gene human mesenchymal stem cells derived from umbilical cord blood has been demonstrated to reduce pathological cavitation, confer protection to myelinated fibers, and promote functional recovery [7]. Previously, we determined that genetic modification of hUCB-MCs with vegf , fgf2, and gdnf genes, when transplanted into the SCI area in rats, enhanced the therapeutic effect of these cells [8–10]. Analysis of these data suggested that the gene-cell hUCB-MC construct with a combination of the vegf and gdnf genes had the greatest potential to enhance posttraumatic recovery and improve the regenerative impact of the carrier cells.…”

Role of GDNF in Spinal Cord Injury Repair

“…Furthermore, this treatment showed reduced astrogliosis, increased axon regeneration, and both autophagy-dependent and autophagy-independent neuroprotection. In a 2016 study [45], human umbilical cord blood mononuclear cells (hUCB-MCs) were combined with an adenoviral vector containing GDNF, following rat thoracic contusion SCI. Adenoviral vectors carrying GDNF as well as hUCB-MCs with adenoviral GDNF showed significantly more tissue sparing than either of the control groups lacking GDNF.…”