SKIN ABNORMALITIES IN MICE TRANSGENIC FOR PLASMINOGEN-ACTIVATOR INHIBITOR-1 - IMPLICATIONS FOR THE REGULATION OF DESQUAMATION AND FOLLICULAR NEOGENESIS BY PLASMINOGEN-ACTIVATOR ENZYMES

Plasminogen activator enzymes have been implicated in the regulation o f growth, migration, and differentiation which occur continually in no rmal epidermis and cyclically in the hair follicle. To elucidate furth er the importance of plasminogen activation in epidermal physiology, s tudies were conducted using mice transgenic for human plasminogen acti vator inhibitor 1 (PAI-1). The epidermis of the newborn (4-7 days) tra nsgenic mice was flaky and showed delayed hair growth compared to that of their control littermates. Histologic analyses revealed a greatly thickened stratum corneum in the transgenics. By 2 weeks after birth, no differences in epidermal morphology were apparent between transgeni c and control littermates. Using in situ hybridization, immunocytochem istry, and in situ reverse zymography techniques, epidermal PAI-1 expr ession was correlated temporally with the aberrant epidermal morpholog y. These data implicate plasminogen activator activity in the regulati on of epidermal shedding and follicular neogenesis. (C) 1995 Academic Press,Inc.