Up-regulation of corticotropin releasing hormone is associated with the downregulation of corticotropinreleasing hormone binding protein and up-regulation of IL33 and IL-8 expression in psoriasis

Purpose: To determine the expression of corticotropin-releasing hormone (CRH) in psoriasis and normal skin biopsy samples, and to correlate the expression of CRH with the expression of CRHBP and inflammatory cytokines IL-8 and IL-33. Methods: Psoriasis and normal skin biopsy samples were obtained from three psoriatic and three normal healthy patients. The mRNA expression was examined by quantitative real-time polymerase chain reaction (qRT-PCR). Protein expression analysis was carried out by western blotting and then further validated by immunohistochemistry. Results: The results revealed that the expression of CRH was highly significantly (p < 0.0001) in psoriatic skin samples compared to normal skin samples. The increase of CRH in psoriatic samples ranged from 2.7- to 3.5-fold. Expression of CRH was associated with concomitant downregulation of CRHBP in all the psoriatic skin biopsy samples. Expression of CRHBP was 3- to 6.2-fold lower in psoriatic samples compared to normal skin samples. Analysis of mRNA expression of IL-8 and IL-33, revealed that expression of both IL-8 and IL-33 was significantly (p < 0.0001) upregulated in psoriatic skin samples. Expression of IL-8 and IL-33 was approximately 4.1 and 3.2-fold higher in psoriatic skin samples than in normal skin samples. Expression of CRHBP, IL-8 and IL-33 was further confirmed by western blotting and immunohistochemistry which the findings from quantitative RT-PCR. Conclusion: Taken together, the results confirm that the expression of CRH is associated with suppression of CRHBP and upregulation of IL-8 and IL-33. Keywords: Psoriasis, Corticotropin releasing hormone, Inflammatory cytokines, Interleukin, Skin biopsy