Combinatorial lentiviral gene delivery of pro‐oligodendrogenic factors for improving myelination of regenerating axons after spinal cord injury

Spinal cord injury (SCI) results in paralysis below the injury and strategies are being developed that support axonal regrowth, yet recovery lags, in part, because many axons are not remyelinated. Herein, we investigated strategies to increase myelination of regenerating axons by overexpression of platelet‐derived growth factor (PDGF)‐AA and noggin either alone or in combination in a mouse SCI model. Noggin and PDGF‐AA have been identified as factors that enhance recruitment and differentiation of endogenous progenitors to promote myelination. Lentivirus encoding for these factors was delivered from a multichannel bridge, which we have previously shown creates a permissive environment and supports robust axonal growth through channels. The combination of noggin+PDGF enhanced total myelination of regenerating axons relative to either factor alone, and importantly, enhanced functional recovery relative to the control condition. The increase in myelination was consistent with an increase in oligodendrocyte‐derived myelin, which was also associated with a greater density of cells of an oligodendroglial lineage relative to each factor individually and control conditions. These results suggest enhanced myelination of regenerating axons by noggin+PDGF that act on oligodendrocyte‐lineage cells post‐SCI, which ultimately led to improved functional outcomes.Spinal cord injury (SCI) results in paralysis below the injury and strategies are being developed that support axonal regrowth, yet recovery lags, in part because many axons are not remyelinated. Herein, we investigated strategies to increase myelination of regenerating axons by overexpression of platelet‐derived growth factor‐AA and noggin either alone or in combination in a mouse SCI model.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146575/1/bit26838_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146575/2/bit26838.pd

Accelerated Axonal Loss Following Acute CNS Demyelination in Mice Lacking Protein Tyrosine Phosphatase Receptor Type Z

Protein tyrosine phosphatase receptor type Z (Ptprz) is widely expressed in the mammalian central nervous system and has been suggested to regulate oligodendrocyte survival and differentiation. We investigated the role of Ptprz in oligodendrocyte remyelination after acute, toxin-induced demyelination in Ptprz null mice. We found neither obvious impairment in the recruitment of oligodendrocyte precursor cells, astrocytes, or reactive microglia/macrophage to lesions nor a failure for oligodendrocyte precursor cells to differentiate and remyelinate axons at the lesions. However, we observed an unexpected increase in the number of dystrophic axons by 3 days after demyelination, followed by prominent Wallerian degeneration by 21 days in the Ptprz-deficient mice. Moreover, quantitative gait analysis revealed a deficit of locomotor behavior in the mutant mice, suggesting increased vulnerability to axonal injury. We propose that Ptprz is necessary to maintain central nervous system axonal integrity in a demyelinating environment and may be an important target of axonal protection in inflammatory demyelinating diseases, such as multiple sclerosis and periventricular leukomalacia. (Am J Pathol 2012, 181:1518-1523; http://dx.doi.org/10.1016/j.ajpath.2012.07.011)UK Multiple Sclerosis SocietyMultiple Sclerosis International FederationUniv Cambridge, Dept Vet Med, Cambridge CB3 0ES, EnglandUniv Cambridge, Wellcome Trust & MRC Cambridge Stem Cell Inst, Cambridge CB3 0ES, EnglandUniversidade Federal de São Paulo, Dept Biosci, Santos, BrazilMerck Serono Int, Geneva Res Ctr, Geneva, SwitzerlandUniversidade Federal de São Paulo, Dept Biosci, Santos, BrazilWeb of Scienc

Central but not systemic administration of XPro1595 is therapeutic following moderate spinal cord injury in mice

BACKGROUND: Glial cell activation and overproduction of inflammatory mediators in the central nervous system (CNS) have been implicated in acute traumatic injuries to the CNS, including spinal cord injury (SCI). Elevated levels of the proinflammatory cytokine tumor necrosis factor (TNF), which exists in both a soluble (sol) and a transmembrane (tm) form, have been found in the lesioned cord early after injury. The contribution of solTNF versus tmTNF to the development of the lesion is, however, still unclear. METHODS: We tested the effect of systemically or centrally blocking solTNF alone, using XPro1595, versus using the drug etanercept to block both solTNF and tmTNF compared to a placebo vehicle following moderate SCI in mice. Functional outcomes were evaluated using the Basso Mouse Scale, rung walk test, and thermal hyperalgesia analysis. The inflammatory response in the lesioned cord was investigated using immunohistochemistry and western blotting analyses. RESULTS: We found that peripheral administration of anti-TNF therapies had no discernable effect on locomotor performances after SCI. In contrast, central administration of XPro1595 resulted in improved locomotor function, decreased anxiety-related behavior, and reduced damage to the lesioned spinal cord, whereas central administration of etanercept had no therapeutic effects. Improvements in XPro1595-treated mice were accompanied by increases in Toll-like receptor 4 and TNF receptor 2 (TNFR2) protein levels and changes in Iba1 protein expression in microglia/macrophages 7 and 28 days after SCI. CONCLUSIONS: These studies suggest that, by selectively blocking solTNF, XPro1595 is neuroprotective when applied directly to the lesioned cord. This protection may be mediated via alteration of the inflammatory environment without suppression of the neuroprotective effects of tmTNF signaling through TNFR2

Cortical AAV-CNTF gene therapy combined with intraspinal mesenchymal precursor cell transplantation promotes functional and morphological outcomes after spinal cord injury in adult rats

Ciliary neurotrophic factor (CNTF) promotes survival and enhances long-distance regeneration of injured axons in parts of the adult CNS. Here we tested whether CNTF gene therapy targeting corticospinal neurons (CSN) in motor-related regions of the cerebral cortex promotes plasticity and regrowth of axons projecting into the female adult F344 rat spinal cord after moderate thoracic (T10) contusion injury (SCI). Cortical neurons were transduced with a bicistronic adeno-associated viral vector (AAV1) expressing a secretory form of CNTF coupled to mCHERRY (AAV-CNTFmCherry) or with control AAV only (AAV-GFP) two weeks prior to SCI. In some animals, viable or nonviable F344 rat mesenchymal precursor cells (rMPCs) were injected into the lesion site two weeks after SCI to modulate the inhibitory environment. Treatment with AAV-CNTFmCherry, as well as with AAV-CNTFmCherry combined with rMPCs, yielded functional improvements over AAV-GFP alone, as assessed by open-field and Ladderwalk analyses. Cyst size was significantly reduced in the AAV-CNTFmCherry plus viable rMPC treatment group. Cortical injections of biotinylated dextran amine (BDA) revealed more BDA-stained axons rostral and alongside cysts in the AAV-CNTFmCherry versus AAV-GFP groups. After AAV-CNTFmCherry treatments, many sprouting mCherry-immunopositive axons were seen rostral to the SCI, and axons were also occasionally found caudal to the injury site. These data suggest that CNTF has the potential to enhance corticospinal repair by transducing parent CNS populations

Spinal Cord Injuries and Evaluation of Treatments

Spinal cord injuries (SCI) are common injuries that do not currently have a fully successful treatment. These injuries cause many physical, psychological, and social burdens for the injured person and any close friends or family members. Older treatment options include surgery, pharmacotherapy, and physical therapy, while newer treatment options include stem cell therapy, bionics, and electrical stimulation. After a full evaluation of the treatments, it was concluded that the best treatment for today is pharmacotherapy, but with more research, stem cell therapy will become the ideal treatment for SCI in the future

The Pathogenesis Of Primary Progressive Multiple Sclerosis: Antibody-Mediated Attack And No Repair?

Primary progressive multiple sclerosis (MS) differs from the more common form of MS which has an initial relapsing-remitting course in a number of ways, including pathological features, clinical course, differential diagnosis and response to treatment. The lesions in primary progressive MS tend to be more diffuse, less inflammatory and less likely to remyelinate than those occurring in relapsing-remitting MS and secondary progressive MS; there are also fewer focal lesions in the brain in primary progressive MS. Recent evidence suggests that antibodies to central nervous system (CNS) antigens have an important role in disease progression. Such antibodies could cause demyelination, inhibit remyelination and cause axonal destruction. Ongoing immune attack by autoantibody and lack of CNS repair could be responsible for the gradually increasing disability in primary progressive MS. Further research on the B-cell and autoantibody response in primary progressive MS might lead to advances in diagnosis and treatment. Inhibition of autoantibody production by inducing B-cell apoptosis with rituximab is a potential new therapy for primary progressive MS

Proton magnetic resonance spectroscopy in multiple sclerosis.

Proton magnetic resonance spectroscopy ((1)H-MRS) provides tissue metabolic information in vivo. This article reviews the role of MRS-determined metabolic alterations in lesions, normal-appearing white matter, gray matter, and spinal cord in advancing our knowledge of pathologic changes in multiple sclerosis (MS). In addition, the role of MRS in objectively evaluating therapeutic efficacy is reviewed. This potential metabolic information makes MRS a unique tool to follow MS disease evolution, understand its pathogenesis, evaluate the disease severity, establish a prognosis, and objectively evaluate the efficacy of therapeutic interventions