Gene transfer to the spinal cord neural scar with lentiviral vectors: predominant transgene expression in astrocytes but not in meningeal cells.

Viral vector-mediated overexpression of neurotrophins in cells constituting the neural scar may represent a powerful approach to rendering scar tissue of a central nervous system (CNS) lesion permissive for neuronal regrowth. In this study a lentiviral vector encoding green fluorescent protein (LV-GFP) was injected in and around the neural scar 2 weeks after a dorsal column lesion in the rat spinal cord in order to analyze transduction characteristics of the neural scar after 4, 7, and 14 days. GFP expression was found at all points after injection and increased from 4 to 7 days, with no apparent difference observed between 7 and 14 days. The core of the lesion was virtually devoid of GFP signal despite direct vector injections in this area. The colocalization of GFP with specific cell markers (GFAP, vimentin, Raldh2, NeuN, OX-42, ED-1, and NG-2) indicated that the predominant cells transduced in the rim of the lesion were astrocytes, with neurons, microglia, oligodendrocyte precursors, and macrophages transduced to a lesser extent. None of the Raldh2-positive meningeal cells, present in the core of the scar, expressed GFP. In vitro meningeal cells were readily transduced, indicating that in vivo the formation of an extracellular matrix might prevent LV particles from transducing cells in the core of the scar. Because astrocytes are important cellular constituents of the glial scar after CNS injury, transduction of astrocytes with LV vectors encoding neurotrophic factors like BDNF or NT-3 may be used to enhance regeneration of severed axonal tracts through or along boundaries of a CNS lesion.

Hendriks WT ，Eggers R ，Verhaagen J ，Boer GJ ... -  《JOURNAL OF NEUROSCIENCE RESEARCH》

Lentiviral vector-mediated transduction of neural progenitor cells before implantation into injured spinal cord and brain to detect their migration, deliver neurotrophic factors and repair tissue.

Blits B ，Kitay BM ，Farahvar A ，Caperton CV ，Dietrich WD ，Bunge MB ... -  《RESTORATIVE NEUROLOGY AND NEUROSCIENCE》

Lentiviral vector-mediated reporter gene expression in avulsed spinal ventral root is short-term, but is prolonged using an immune "stealth" transgene.

Hendriks WT ，Eggers R ，Carlstedt TP ，Zaldumbide A ，Tannemaat MR ，Fallaux FJ ，Hoeben RC ，Boer GJ ，Verhaagen J ... -  《RESTORATIVE NEUROLOGY AND NEUROSCIENCE》

Loss of gene expression in lentivirus- and retrovirus-transduced neural progenitor cells is correlated to migration and differentiation in the adult spinal cord.

Vroemen M ，Weidner N ，Blesch A 《EXPERIMENTAL NEUROLOGY》

Ex vivo and in vitro studies of transgene expression in rat astrocytes transduced with lentiviral vectors.

Implantation of cells genetically modified to express therapeutic genes into the brain has been proposed as a potential treatment for neurodegenerative diseases. In the current study embryonic rat-derived astrocytes were cultured and transduced with a lentiviral vector expressing the reporter gene green fluorescent protein (GFP) and subsequently grafted into the adult rat brain. The proportion of GFP expressing cells was stable, albeit small (1%), at all survival times, up to 6 weeks, the longest time point studied. In parallel in vitro studies, the astrocytes were lentivirally transduced to express either one of the two isoforms of glutamate decarboxylase (GAD(65) or GAD(67)) or glial cell line-derived neurotrophic factor (GDNF). When transducing 293T cells with the two GAD vectors, released GABA could be measured using high-performance liquid chromatography. Further studies of rat astrocytes transduced with the same vectors resulted in a level of GAD activity about 10 times higher than the activity of an intact rat striatum. One hundred thousand astrocytes transduced with LV-GDNF released approximately 27 ng of GDNF per hour. Thus, taken together, our observations provide support for the use of rat astrocytes in ex vivo gene transfer of these proteins in animal models of CNS disorders, e.g., Parkinson's disease or epilepsy.

Ericson C ，Wictorin K ，Lundberg C 《EXPERIMENTAL NEUROLOGY》