EXPRESSION OF PLACENTA GROWTH FACTOR CYCLOOXYGENASE AND THYMUS-AND ACTIVATION-REGULATED CHEMOKINE IN THE EPIDERM IN VITRO HUMAN SKIN EQUIVALENT.
In vitro skin equivalent models are finding increased utility as tools in basic skin research, safety assessment and product development processes. To further utilization for these purposes, we are currently defining a growing list of physiologically significant molecular endpoints to monitor the effects of experimental treatments on EpiDerm™ in vitro human skin tissue. In the present work, we have investigated the expression in EpiDerm of cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), placenta growth factor (PlGF), and thymus and activation-regulated chemokine (TARC) at the mRNA level The cyclooxygenase product prostaglandin E2 (PGE2) is thought to be an important mediator of skin carcinogenesis (1-3). Irradiation of EpiDerm with UVB caused elevated levels of cyclooxygenase product prostaglandin E2 (PGE2) secretion into the culture medium. Experiments with selective COX inhibitors indicate a prominent role for COX-2 in UVB-induced PGE2 production. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect both COX-1 and COX-2 message in EpiDerm. COX-2 message was induced while COX-1 message was decreased upon exposure to UVB. We also investigated expression of placenta growth factor (PlGF) in the EpiDerm model. PlGF and related vascular endothelial growth factors (VEGF) are potentangiogenesis-inducing factors believed to play important roles in development of skin cancers (4,5). Previous microarray experiments revealed the induction of PlGF after UVB-irradiation of EpiDerm (6). In the present work we utilized RT-PCR to confirm the induction of PlGF in UVB-irradiated EpiDerm tissue. H2O2 was also found to induce PlGF in EpiDerm tissue. Lastly, we investigated the expression of TARC in EpiDerm tissue. TARC is a highly specific chemoattractant for Th2 cells, which play a prominent role in atopic dermatitis (7-8). A combination of interferon-γ and tumor necrosis factor-α induced the expression TARC mRNA in EpiDerm. These endpoints expand the utility of in vitro human skin equivalents for studies involving skin inflammation, skin cancer, topical sensitization and related skin phenomena.
COX-1, COX-2, Chemoattractant, Cyclooxygenase-1, Cyclooxygenase-2, Dermatitis atopic, EpiDerm, Gene expression, Genotoxicity, Interferon-y, Isolation of, Microarray, PGE-2, PIGF, Placenta growth factor, Product development, Prostaglandin E-2, RNA, RT-PCR, Safety assessments, Skin cancer, Skin equivalent, Skin inflammation, Sun screens, TARC, Topical sensitization, UVA, UVB
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