RESUMEN
Phototherapy with UV light is a standard treatment for psoriasis, yet the mechanisms underlying the therapeutic effects are not well understood. Studies in human and mouse keratinocytes and in the skin tissues from human patients and mice showed that UV treatment triggers ubiquitination and downregulation of the type I IFN receptor chain IFNAR1, leading to suppression of IFN signaling and an ensuing decrease in the expression of inflammatory cytokines and chemokines. The severity of imiquimod-induced psoriasiform inflammation was greatly exacerbated in skin of mice deficient in IFNAR1 ubiquitination (Ifnar1(SA)). Furthermore, these mice did not benefit from UV phototherapy. Pharmacologic induction of IFNAR1 ubiquitination and degradation by an antiprotozoal agent halofuginone also relieved psoriasiform inflammation in wild-type but not in Ifnar1(SA) mice. These data identify downregulation of IFNAR1 by UV as a major mechanism of the UV therapeutic effects against the psoriatic inflammation and provide a proof of principle for future development of agents capable of inducing IFNAR1 ubiquitination and downregulation for the treatment of psoriasis.
Asunto(s)
Inflamación/terapia , Piperidinas/farmacología , Psoriasis/terapia , Quinazolinonas/farmacología , Receptor de Interferón alfa y beta/metabolismo , Terapia Ultravioleta/métodos , Animales , Línea Celular , Quimiocinas/metabolismo , Citocinas/metabolismo , Modelos Animales de Enfermedad , Regulación hacia Abajo/efectos de la radiación , Humanos , Inflamación/patología , Queratinocitos/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Psoriasis/patología , Receptor de Interferón alfa y beta/genética , Transducción de Señal , Piel/patología , Ubiquitinación/efectos de los fármacos , Ubiquitinación/efectos de la radiaciónRESUMEN
The purpose of the present study was to establish and characterize serum-free epithelial cultures of normal human conjunctiva using fresh biopsy tissue. To this end, small pieces of normal conjunctiva were biopsied from patients undergoing routine cataract surgery. Fragments of the tissue were placed in explant culture in medium containing fetal bovine serum for approximately 1 week to promote epithelial cell outgrowth. Cultures were then passaged multiple times into serum-free medium. Cultures generated in this way were at least 95% keratinocytes and exhibited a typical epithelial morphology, which was dependent on the extracellular Ca(2+)concentration. Immunocytochemical staining revealed that E-cadherin, P-cadherin, and involucrin were present in the cultures, with distributions consistent with their in vivo localization patterns. Distribution of keratins 19, 3, and 4 in conjunctival epithelial cultures were also consistent with in vivo patterns and distinctly different from patterns observed in epithelial cultures similarly generated from cornea and foreskin. Hence, conjunctival keratinocyte cultures retain some tissue-specific markers and do not revert to a generic, culture phenotype.