RESUMO
Objective:To investigate changes in circadian gene cryptochrome 2 (CRY2) expression in mouse models of psoriasis and HaCaT cells, and to explore underlying mechanisms.Methods:Imiquimod-induced mouse model experiment: 12 C57BL/6 female mice were randomly and equally divided into imiquimod group receiving topical imiquimod treatment for 5 consecutive days and control group receiving no treatment; these mice were sacrificed on day 6, skin tissues were resected from the back of mice, and immunofluorescence staining was performed to determine the CRY2 expression in the epidermis. HaCaT cell transfection experiment: HaCaT cells with small interfering RNA (siRNA) -mediated knockdown of CRY2 served as siRNA-CRY2 group, and siRNA-NC group as control group; 5-ethynyl-2′-deoxyuridine (EdU) staining was performed to evaluate the proliferative activity of the HaCaT cells, real-time fluorescence-based quantitative PCR (qPCR) to determine the mRNA expression of chemokines in the HaCaT cells, and Western blot analysis to determine phosphorylation levels of extracellular signal-regulated kinase 1/2 (ERK1/2) . Tumor necrosis factor-α (TNF-α) -stimulated animal and cell experiments: 12 C57BL/6 female mice were randomly and equally divided into TNF-α group subcutaneously injected with TNF-α solution in the ear for 6 days, and phosphate buffered saline (PBS) group subcutaneously injected with the same amount of PBS; the mice were sacrificed on day 7, skin tissues were resected from the ear of mice, and immunofluorescence staining was conducted to determine the CRY2 expression in the epidermis; CRY2-knockdown HaCaT cells stimulated with 50 ng/ml TNF-α for 12 hours served as siRNA-CRY2 + TNF-α group, and siRNA-NC + TNF-α group as control group; qPCR was performed to determine the mRNA expression of chemokines in HaCaT cells in the above groups. Statistical analysis was carried out by using two-independent-sample t test. Results:Immunofluorescence staining showed that the CRY2 protein expression was significantly lower in the mouse dorsal epidermis in the imiquimod group (0.94 ± 0.23) than in the control group (2.30 ± 0.25, t = 3.99, P = 0.016) . Compared with the siRNA-NC group, the siRNA-CRY2 group showed significantly increased proportions of EdU-positive cells (48.13% ± 10.97% vs. 38.23% ± 0.81%, t = 5.00, P = 0.007) , mRNA expression levels of chemokines CXCL1 and CXCL8, as well as significantly increased phosphorylated (p) -ERK1/2 protein expression levels (all P < 0.05) , while there were no significant differences in the CCL20 mRNA expression or ERK1/2 protein expression between the two groups (both P > 0.05) . Immunofluorescence staining showed significantly decreased CRY2 protein expression level in the mouse ear epidermis in the TNF-α group (0.37 ± 0.34) compared with the PBS group (2.04 ± 0.17, t = 4.38, P = 0.012) ; the relative mRNA expression levels of chemokines CXCL1, CXCL8, and CCL20 in HaCaT cells were significantly higher in the siRNA-CRY2 + TNF-α group than in the siRNA-NC + TNF-α group (all P < 0.05) . Conclusion:CRY2 was markedly underexpressed in psoriasis, which might promote the proliferation of keratinocytes and expression of chemokines CXCL1, CXCL8 and CCL20, and TNF-α might be an upstream cytokine that could downregulate CRY2 expression.
RESUMO
Objective:To investigate the efficacy and safety of infliximab in the treatment of severe plaque psoriasis and its effect on the expression of programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) in psoriatic lesions.Methods:A total of 17 patients with severe plaque psoriasis were enrolled from Shanghai Skin Disease Hospital from February 2019 to April 2019, and were treated with intravenous drips of infliximab at a dose of 5 mg/kg at weeks 0, 2, 6, 14, 22, 30, 38 and 46. Efficacy was evaluated by using the psoriasis area and severity index (PASI) score at weeks 2, 6, 10, 14, 22, 30, 38, 46 and 52, and adverse events were recorded during the trial. Real-time PCR was performed to determine the expression of PD-1 and PD-L1 in skin tissues of 8 volunteer controls, as well as in skin lesions of 14 patients with plaque psoriasis before treatment and 5 patients with plaque psoriasis after 10-week treatment, and immunofluorescence assay to measure the expression of PD-1 and PD-L1 in skin tissues of 5 volunteers and 5 patients with psoriasis. The independent sample t-test was used to compare the expression of PD-1 and PD-L1 in skin tissues between the patients with plaque psoriasis and controls, and paired t-test to compare the expression of PD-1 and PD-L1 in the skin lesions of patients before and after infliximab treatment. Results:After 2, 6, 10, 14, 22, 30, 38, 46 and 52 weeks of infliximab treatment, the proportion of patients with plaque psoriasis achieving PASI75 was 1/17, 6/16, 9/16, 10/16, 15/15, 14/15, 13/14, 11/13 and 10/11, respectively. Antinuclear antibody staining turned positive in 12 patients, which was the most common adverse reaction, and 1 patient experienced an infusion reaction, which was the most severe adverse reaction. Before the treatment, the expression of PD-1 and PD-L1 (1.111 ± 0.391, 0.902 ± 0.169, respectively) was significantly higher in the skin lesions of patients with psoriasis than in the skin tissues of controls (0.620 ± 0.225, t=3.116, P=0.007; 0.474 ± 0.360, t=3.208, P=0.006, respectively) ; after infliximab treatment, the expression of PD-1 and PD-L1 (0.570 ± 0.230, 0.150 ± 0.050, respectively) in the improved skin lesions was significantly lower than that in the corresponding lesions before the treatment (1.238 ± 0.414, t=3.107, P=0.036; 0.966 ± 0.184, t=8.423, P=0.001, respectively) . Conclusions:Infliximab is effective and safe for the treatment of plaque psoriasis, but monitoring is necessary during treatment. The expression of PD-1 and PD-L1 is aberrantly upregulated in plaque psoriasis lesions, and decreased after infliximab treatment, suggesting that PD-1/PD-L1 may be involved in inflammation regulation in psoriasis.