Gene expression profiling in engineered skin substitutes subjected to chemical injury: protective effects of keratinocyte growth factor

In this study we aim at understanding the response of epidermis to barrier disruption by chemical injury. In contrast to cells in culture, engineered skin tissues mimic human epidermis in terms of tissue architecture and exhibit significant barrier function. Skin equivalents were cultured for seven days at the air-liquid interface and then exposed to acetone for various times. Long exposure (>5 min) to acetone resulted in loss of metabolic activity over time. Histological staining showed that the tissues were affected in a time and position-dependent fashion. Using the TUNEL assay we found that exposure to acetone increased apoptosis especially in the upper layers of the epidermis. Interestingly, addition of KGF reduced apoptosis significantly. To identify changes of gene expression in response to barrier disruption and KGF treatment, we employed cDNA micro-array technology. We found that acetone treatment increased the levels of several genes, which are involved in apoptosis. Interestingly, KGF downregulated genes that promote apoptosis and upregulated genes that promote cell survival. Our results suggest that KGF may exert its protective effect(s) by preventing apoptosis. Furthermore, we propose that functional genomics may be used in tissue engineering to understand tissue development, wound regeneration and response to environmental stimuli.