Possible role of Malassezia furfur in psoriasis: modulation of TGF-beta1, integrin, and HSP70 expression in human keratinocytes and in the skin of psoriasis-affected patients.
BACKGROUND
Psoriasis is a disease characterized by an abnormal pattern of keratinocyte growth and differentiation. Malassezia furfur forms part of the normal human skin flora. It may also be involved in the pathogenesis of psoriasis. To define the role of M. furfur in the pathogenesis of psoriasis, we investigated how M. furfur regulates molecules involved in cell migration and proliferation. The experiments were performed using human keratinocytes and skin biopsies from M. furfur-positive and -negative psoriasis-affected patients. In addition, we examined the signal transduction mechanisms involved.


METHODS
Western blot analysis was performed on human keratinocytes lysates treated or untreated with M. furfur and on biopsies from healthy and psoriasis patients. Signal transduction mechanisms involved were evaluated by electrophoretic mobility shift assay using the AP-1 inhibitor curcumin.


RESULTS
We found that M. furfur up-regulates transforming growth factor-beta1 (TGF-beta1), integrin chain, and HSP70 expression in human keratinocytes via AP-1-dependent mechanism. In the biopsies of M. furfur-positive psoriasis-affected patients, an increase in TGF-beta1, integrin chains, and HSP70 expression was found.


CONCLUSIONS
Our data suggest that M. furfur can induce the overproduction of molecules involved in cell migration and hyperproliferation, thereby favoring the exacerbation of psoriasis.
Baroni
Adone
A
Department of Dermatology, Second University of Naples, Via Constantinopoli 16, 80138 Naples, Italy.
Paoletti
Iole
I
Ruocco
Eleonora
E
Agozzino
Marina
M
Tufano
Maria Antonietta
MA
Donnarumma
Giovanna
G
D015153:Blotting, Western; D002455:Cell Division / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D015603:Keratinocytes / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D008290:Malassezia / Q000472:pathogenicity* / Q000502:physiology; D011565:Psoriasis / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D015398:Signal Transduction; D012867:Skin / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D018808:Transcription Factor AP-1 / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D053773:Transforming Growth Factor beta1
D018840:HSP70 Heat-Shock Proteins; D016023:Integrins; C508960:TGFB1 protein, human; D018808:Transcription Factor AP-1; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1