Expression and significance of Caspase-1, Gasdermin D and N-terminal fragment of GSDMD in serum and lesions of patients with psoriasis vulgaris

Objective To detect the expressions of Caspase-1 in serum and Caspase-1, Gasdermin D (GSDMD) as well as N-terminal fragment of GSDMD(GSDMD-N) in lesions of patients with psoriasis vulgaris, and further explore the role of pyroptosis in psoriasis.

Methods A total of 30 patients with progressive psoriasis vulgaris were enrolled into psoriasis group (PSO group). Serum samples from 30 healthy subjects who underwent physical examinations in the Physical Examination Center of Northern Jiangsu People's Hospital and skin tissue (skin lesions) from 20 healthy aesthetic seekers in Department of Plastic Surgery were collected and included in healthy control group (CON group). The expression of Caspase-1 mRNA in the serum was detected by Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR); the levels of serum Caspase-1 of two groups were detected by enzyme linked immunosorbent assay (ELISA); the expression of proteins of Caspase-1 in samples of skin tissues were detected by western blot; the expression and distribution of GSDMD and GSDMD-N in samples of skin tissues were detected by immunohistochemical method(IHC).

Results The expression level of Caspase-1 mRNA in serum of the PSO group was significantly higher than that of in the CON group (P<0.01). The level of serum Caspase-1 protein expression in the PSO group was (1 047.74±276.20) pg/mL, which was significantly higher than (371.20±160.84) pg/mL in the CON group (P<0.01). The expression level of total Caspase-1 protein between PSO group and CON group showed no significant difference(P>0.05). The expression level of Pro-Caspase-1 protein in skin lesions of the PSO group was significantly lower than that in the CON group, and the positive rates of expression of Cleaved Caspase-1 protein and GSDMD protein of the PSO group were significantly higher than those in the CON group (P<0.01). The positive rates of expression of GSDMD-N protein in skin lesions of the PSO group was significantly higher than that in the CON group (P<0.01).

Conclusion The expressions of Caspase-1 in serum and skin lesions, GSDMD and GSDMD-N in skin lesions are increased in patients with psoriasis vulgaris in active stage, suggesting that the pyroptosis pathway may be involved in the occurrence and development of psoriasis vulgaris.