Integration of genetically modified adult astrocytes into the lesioned rat spinal cord

Abstract

Combination of ex vivo gene transfer and cell transplantation is now considered as a potentially useful strategy for the treatment of spinal cord injury. In a perspective of clinical application, autologous transplantation could be an option of choice. We analyzed the fate of adult rat cortical astrocytes genetically engineered with a lentiviral vector transplanted into a lesioned rat spinal cord. Cultures of adult rat cortical astrocytes were infected with an HIV-1-derived vector (TRIP-CMV-GFP) and labeled with the fluorescent dye Hoechst. Transfected and labeled astrocyte suspension was injected at T11 in rats in which spinal cord transection at T7-T8 levels had been carried out 1 week earlier. Six weeks after grafting, the animals were sacrificed and transplants were retrieved either by Hoechst fluorescence or by immunohistochemistry for detection of glial fibrillary acidic protein (GFAP) and vimentin. Grafted astrocytes expressing green fluorescent protein (GFP) were found both at the injection and transection sites. Genetically modified astrocytes thus survived, integrated, and migrated within the host parenchyma when grafted into the completely transected rat spinal cord. In addition, they retained some ability to express the GFP transgene for at least 6 weeks after transplantation. Adult astrocytes infected with lentiviral vectors can therefore be a valuable tool for the delivery of therapeutic factors into the lesioned spinal cord.

Effect of cyclosporin A on functional recovery in the spinal cord following contusion injury

“…The GFAP group represents the regular active astrocytes already present in that area of the spinal cord, while the GFAP‐ and vimentin‐expressing group are reactive astrocytes which proliferate and migrate to the site of injury following spinal cord injury. Vimentin is expressed initially during development by immature astrocytes and is re‐expressed by reactive astrocytes following spinal cord injury (Pencalet et al. 2006).…”

“…The GFAP group represents the regular active astrocytes already present in that area of the spinal cord, while the GFAP-and vimentin-expressing group are reactive astrocytes which proliferate and migrate to the site of injury following spinal cord injury. Vimentin is expressed initially during development by immature astrocytes and is re-expressed by reactive astrocytes following spinal cord injury (Pencalet et al 2006). Similar to the case of macrophages and microglia, reactive astrocytes appear to have a phase-dependent role following spinal cord injury which accounts for seemingly conflicting functions (Okada et al 2006).…”

Biomaterial-Supported Cell Transplantation Treatments for Spinal Cord Injury: Challenges and Perspectives

“…This was found to be due to the astrocytic migration to the nucleus gracilis, where they protected neurons from denervation, increasing neuronal survival and networks only from astrocytes migrating out of the E14 spinal tissue but not from the E14 derived spinal cord astrocytes. Moreover, GFP labeled adult rat cortical astrocytes injected caudally (T11) 1 week after a T7-T8 full transection showed survival, integration and long distance migration to the lesion site and beyond 6 weeks post-transplantation (Pencalet et al, 2006 ).…”

Gemfibrozil, stretching arms beyond lipid lowering

“…Upon activation, both microglia and astrocytes release many inflammatory molecules including inflammatory cytokines TNF-α, IL-1β, IL-6, IL-12; chemokines including CCL2, 4, 6, 8 and CXCL10; or even, small diffusible chemical compounds including NO and ROS. These molecules participate in wide range of inflammatory reactions contributing to the pathology of MS and EAE (49,50). Because gemfibrozil inhibits the expression of these neurotoxic and inflammatory molecules from both microglia and astrocytes; we and others examined the effect of this lipid lowering drug on the disease process of EAE and reported suppression of EAE at multiple steps [14,40,41,44].…”