L5   THE HAIR FOLLICLE AS A TARGET FOR GENE THERAPY

Domashenko A., Gupta S., Cotsarelis G. Dept of Dermatology, University of Pennsylvania Medical School, Philadelphia, PA.

The topical delivery of transgenes to hair follicles is a potentially powerful approach for treating disorders of the skin and hair. Here we show that the topical administration of liposome/DNA mixtures (lipoplex) to mouse skin and to human skin xenografts resulted in efficient in vivo transfection of hair follicle cells. Transfection depended on liposome composition, and occurred only at the onset of a new growing stage of the hair cycle. By manipulating the hair follicle cycle with depilation and retinoic acid treatment, xenografts were transfected at an efficiency of almost 50% at anagen onset. Transgenes administered in this fashion were selectively expressed in hair progenitor cells, and therefore have the potential to affect the characteristics of the follicle. These findings form a foundation for the future use of topical lipoplex applications to alter hair follicle phenotype and treat diseases of the hair and skin.