Transduction of cultured oligodendrocytes from normal and twitcher mice bya retroviral vector containing human galactocerebrosidase (GALC) cDNA

Krabbe disease or globoid cell leukodystropy is a lysosomal disorder caused by a deficiency of galactocerebrosidase (GALC) activity. This results in d efects in myelin that lead to severe symptoms and early death in most human patients and animals with this disease. With the cloning of the GALC gene and the availability of the mouse model, called twitcher, it was important to evaluate the effects of providing GALC via a retroviral vector to oligod endrocytes in culture. After differentiation, the untransduced cells from n ormal mice extended highly branched processes while those from the twitcher mice did not. Oligodendrocytes in culture can be readily transduced to pro duce much higher than normal levels of GALC activity. Transduced normal and twitcher cells formed clusters when plated at high density. Transduction o f twitcher oligodendrocytes plated at lower density, followed by differenti ation, resulted in some cells having a completely normal appearance with hi ghly branched processes. Other cells showed retraction and fragmentation. P erhaps over expression of GALC activity may be detrimental to oligodendrocy tes. These studies demonstrate that the phenotype of twitcher oligodendrocy tes can be corrected by providing GALC via gene transfer, and this could le ad the way to future studies to treat this disease.