| Objective: Psoriasis is a common chronic inflammatory skin disease.At present,the specific pathogenesis of psoriasis is not yet clear,and there is no complete cure.It is essential to find new therapeutic targets.The study found that the prevalence of metabolic syndrome in patients with psoriasis was higher than in healthy people.There is a significant correlation between FTO gene SNP and obesity,hypertension and fasting blood glucose abnormality.FTO protein is also one of m6 A demethylase.Therefore,this study used lipopolysaccharide(LPS)-induced keratinocyte model and imiquimod(IMQ)-induced psoriasis-like dermatitis in mice to investigate whether FTO has an Impact on the mechanism of psoriasis.Methods: 1.Keratinocytes were randomized into two groups:(1)Normal group: culture under normal conditions;(2)LPS group: LPS stimulation for 24 hours to induced inflammation model.2.qRT-PCR was used to detect the mRNA expression level of FTO in keratinocytes;Western blot was used to detect the expression of FTO in keratinocytes.3.IMQ-induced psoriasiform dermatitis model,10 female BALB/c mice were randomized into two groups:(1)Experimental group: mice were treated with IMQ cream for 7 consecutive days.(2)Control group: The same amount of Vaseline cream was applied for 7 days in a row.The pathological changes of the skin lesions were observed and the expression of FTO in the skin lesions of mice was detected by qRT-PCR and Western blot.5.IMQ induced mouse psoriasis model,15 female BALB/c mice were randomly divided into three groups:(1)Experimental group: mice were treated with IMQ cream for 7 consecutive days,and on the first and fourth day respectively intradermally injected lentivirus to silence FTO.(2)Model group: Mice were treated with IMQ,and the same titer of the negative control virus was intradermally injected on the first day and the fourth day.(3)Control group: Vaseline cream was applied externally for 7 days,and the same titer of the negative control virus was intradermally injected on the first day and the fourth day.The degree of inflammation of the dorsal skin lesions in mice was assessed using the Clinical Psoriasis Area and Severity Index(PASI)objective scoring system.6.The peripheral blood of mice was taken through eyeball and the back lesions of the mice were excised.The pathological changes of the skin lesions were observed.The expression of FTO in the lesions of mice was detected by immunohistochemistry and Western blot.The expression level of inflammatory factors in mouse skin lesions was detected by qRT-PCR,and the expression level of inflammatory factors in peripheral blood serum of mice was detected by ELISA.Western blot was used to detect the expression of m6 A methyltransferase and desmethylase in the lesions of IMQ-induced psoriasis-like dermatitis mice and normal control mice.Results: In vitro,we found that the expression of FTO in keratinocytes induced by LPS was significantly higher than that in the control group by qRT-PCR and Western blot,and the difference was statistically significant(P<0.05).2.In the in vivo experiment,it was observed by the naked eye that the large erythema on the back of the experimental group was covered with white scaly,while the control mice had no visible lesion on the back.The results of HE staining showed that the epidermal hyperkeratosis,epidermal protrusion,keratosis and acanthosis were observed in the experimental group.No obvious abnormalities were observed in the control group.The results of qRT-PCR and Western blot showed that the amount of FTO in the skin lesions of the experimental group was significantly higher than that of the control group,and it was statistically significant(P<0.05).3.In the in vivo experiment,it was observed by the naked eye that the large erythema on the back of the model group was covered with white scaly.The back skin lesions of the mice in the experimental group were mild,while the mice in the control group had no visible lesions on the back.HE staining results showed that the model group showed excessive keratinization of the epidermis,prolongation of epidermal processes,keratosis,and acanthosis.In the experimental group,hyperkeratosis and acanthosis were observed,but the degree was lower than that of the model group.No obvious abnormalities were observed in the control group.The results of immunohistochemistry showed that FTO in the keratinocyte nucleus of the model group was highly expressed with brown granules.The expression level of FTO in the nucleus of the epidermal cells of the experimental group was significantly lower than that of the model group,but no brownish yellow granules were observed in the keratinocytes of the control group.There were significant differences among the model group,the control group and the experimental group(P<0.05).The results of Western blot showed that the amount of FTO in the skin lesions of the model group was significantly higher than that of the control group.The amount of FTO in the skin lesions of the experimental group was significantly lower than that of the model group,but higher than that of the control group.There were statistically significant differences among the model group,the experimental group and the control group(P<0.05).The results of ELISA showed that the skin lesions and serum inflammatory factors IL-17 and IL-23 in the experimental group were higher than those in the model group,and there was statistically significant difference between two groups(P<0.05).The skin lesions and serum inflammatory factors in the experimental group and the model group were higher than those in the control group.The results were statistically significant(P<0.05).The expressions of m6 A methylases METTL4,WTAP,demethylase FTO and ALKBH5 in the experimental group were significantly higher than those in the control group(P<0.05).But the difference in FTO expression is the most significant.Conclusion: Our results show that FTO may be an important part in the pathogenesis of psoriasis,which may promote the development of psoriasis through demethylation. |
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