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

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.

Abnormal production of the TNF-homologue APRIL increases the proliferation of human malignant glioblastoma cell lines via a specific receptor.

A proliferation-inducing ligand (APRIL) of the tumour necrosis factor (TNF) family is produced in small amounts in many tissues and more abundantly in tumours. APRIL has been reported to promote cell growth in vivo and in vitro. It was recently shown that the production of APRIL in some glioblastoma cell lines does not lead to an increase in cell growth. In this study, we investigated the production of APRIL and its ability to increase the proliferation of eight human glioblastoma cell lines. We found that APRIL was produced in the eight human glioblastoma cell lines tested but not in the normal embryonic astrocyte counterparts of glioblastomas. Flow cytometry demonstrated the presence of a specific APRIL-binding receptor on the cell surface in all the glioblastoma cell lines tested. This receptor was also present on normal embryonic and adult astrocytes and embryonic neural progenitor cells. Moreover, the addition of recombinant human APRIL resulted in an increase in proliferation rate of normal adult astrocytes and in four of eight cell lines tested. Addition of the soluble recombinant TNF-receptor-homologue B-cell maturation (BCMA) chimeric protein, which binds APRIL, confirmed the involvement of APRIL in the growth of malignant glioblastoma cell lines.