Summary: The deubiquitinating enzyme ubiquitin specific peptidase 15 (USP15) is regarded as a regulator of TGFβ signaling pathway. This process depends on Smad7, the inhibitory factor of the TGFβ signal, and type Ⅰ TGFβ receptor (TβR- Ⅰ ), one of the receptors of TGFβ. The expression level of USP 15 seems to play vital roles in the pathogenesis of many neoplasms, but so far there has been no report about USP15 in psoriasis. In this study, immunohistochemical staining of USP15, TβR- Ⅰ and Smad7 was performed in 30 paraffin-embedded psoriasis specimens and 10 normal specimens to investigate the expression of USP15, TβR- Ⅰ and Smad7 in psoriasis and to explore the relevance among them. And USP 15 small interfering RNA (USP 15 siRNA) was used to transfect Hacat cells to detect the mRNA expression of TβR- Ⅰ and Smad7. Of 30 cases of psoriasis in active stage, 28, 24 and 26 cases were positive for USP15, TβR- Ⅰ and Smad7 staining, respectively. The positive rates of USP15 and Smad7 were significantly higher in psoriasis specimens than in normal skin specimens (44.1%±26.0% vs. 6.1%±6.6%, 47.2%±27.1% vs. 6.6%±7.1%), and positive rate of TβR- I (20.3%±22.2%) in psoriasis was lower than that in normal skin specimens (46.7%±18.2%). There was a significant positive correlation between USP15 and Smad7 expression, and significant negative correlations between USP15 and TβR- Ⅰ expression, and between TβR- Ⅰ and Smad7 expression in psoriasis. After transfection of USP15 siRNA in Hacat ceils, the expression ofTβR- Ⅰ mRNA was up-regulated and that of Smad7 was down-regulated. It is concluded that USP15 may play a role in the pathogenesis of psoriasis through regulating the TβR- Ⅰ/Smad7 pathway and there may be other cell signaling pathways interacting with USP 15 to take part in the development of psoriasis.
Summary: This study examined the correlation of the expression of interleukin-36 (IL-36), a novel member of interleukin-1 (IL-1) family, with p38 mitogen-activated protein kinase (p38 MAPK) and nu clear factor-kappa B (NF-kB) pathways in psoriasis vulgaris skin lesions. The expression levels of IL-36a, IL-3613, IL-367, phosphorylated p38 MAPK, and NF-id3p65 were detected in the skin tissues of 38 psoriasis patients and 17 healthy control subjects by real-time quantitative reverse transcription po lymerase chain reaction (qRT-PCR) and Western blotting. The cytokine expression levels were com pared between the psoriasis group and the control group. A correlation analysis between cytokine pro teins was performed in the psoriasis group. Results showed that the expression levels of IL-36a, IL-3613, IL-36y, phosphorylated p38 MAPK and NF-rh3p65 in the psoriasis group were Significantly higher than those in the control group (P〈0.001). In the psoriasis group, the IL-36 cytokine expression was positively correlated with phosphorylated p38 MAPK and NF-kBp65 expression (P〈0.05). A significant positive correlation was also found between the phosphorylated p38 MAPK and NF-v,.Bp65 expression (P〈0.01). It was concluded that the increased IL-36 expression is correlated with p38 MAPK and NF-kB pathways in psoriasis vulgaris skin lesions. All the three factors may be jointly involved in the pathogenesis and local inflammatory response of psoriasis.