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Are stress proteins induced during PUVA therapy?
A S Al-Masaud1, E J Wood, W J Cunliffe
1Department of Biochemistry and Molecular Biology, University of Leeds, U.K.
The British Journal of Dermatology
|May 1, 1996
Summary
Psoralen and ultraviolet A (PUVA) therapy raises skin temperature but does not trigger a heat shock protein (HSP) response in patients. However, in vitro studies show PUVA induces HSP90 and HSP70 synthesis in keratinocytes without mRNA level changes.
Area of Science:
- Dermatology
- Molecular Biology
- Biophysics
Background:
- Heat shock proteins (HSPs) are cellular protective proteins activated by temperature stress.
- Psoralen and ultraviolet A (PUVA) therapy is a common treatment for psoriasis.
- PUVA treatment involves exposure to UV light and a photosensitizing agent, potentially causing thermal stress.
Purpose of the Study:
- To investigate whether PUVA therapy induces a heat shock response in human epidermis.
- To compare in vivo and in vitro responses to thermal stress induced by PUVA.
Main Methods:
- Measuring skin temperature during PUVA treatment in psoriasis patients.
- Analyzing epidermal samples for heat shock protein (HSP90, HSP70) production and mRNA levels.
- Exposing cultured keratinocytes to simulated PUVA conditions in vitro.
Main Results:
- In vivo, PUVA treatment caused a mean skin temperature increase of 5.3°C, but no detectable HSP response in epidermal samples.
- In vitro, a 5-7°C temperature rise induced HSP90 and HSP70 production in epidermal and keratinocyte cultures.
- In vitro simulated PUVA increased HSP90 and HSP70 synthesis in keratinocytes, but this did not correlate with mRNA level changes.
Conclusions:
- The thermal stress from clinical PUVA treatment is insufficient to elicit an in vivo heat shock response in the skin.
- In vitro models demonstrate that keratinocytes can produce HSP90 and HSP70 in response to simulated PUVA, suggesting post-transcriptional regulation may be involved.