Heat shock protein 70 upregulates interleukin-6 expression by fibroblasts from psoriasis vulgaris lesions

Abstract

Objective To evaluate the in vitro effect of heat shock protein 70(HSP70)on interleukin-6 (IL-6)expression by cultured fibroblasts from psoriasis vulgaris lesions(PFbs).Methods Fibroblasts were isolated from the lesions of patients with psoriasis vulgaris and subjected to a primary culture.After 3 to 5 passages of culture,the fibroblasts were collected and used in the next experiment.Some PFbs were cultured with different concentrations(5,10,20,30 mg/L)of HSP70 for 48 hours,or with HSP70 of 30 mg/L for different durations(3,6,12,24,48,72 hours);some PFbs were incubated with HSP70 of 30 mg/L for 24 hours after pretreatment with pyrrolidine dithiocarbamate(PDTC,a specific inhibitor of nuclear factor-kappa B)for 30 minutes.PFbs receiving no treatment served as the control.Enzyme-linked immunosorbent assay(ELISA)and semi-quantitative reverse transcription PCR were performed to measure the IL-6 protein expression in culture supematant and IL-6 mRNA expression by PFbs,respectively.Differences in the expression of IL-6 protein and mRNA between PFbs receiving different treatment were analyzed by using t test and Dunnett's t test.Results HSP70 significantly increased both protein production and mRNA expression of IL-6 in a time(0-48 h)-and dose(5-30 mg/L)-dependent manner.The expression levels of supernatant IL-6 protein and IL-6 mRNA were significantly higher in the PFbs treated with HSP70 of 10 mg/L for 48 hours than untreated PFbs((75.2 ± 15.4)ng/L vs.(47.2 ± 10.6)ng/L,0.439 ± 0.093 vs.0.249 ± 0.069,both P ＜ 0.05).A significant increase was observed as early as 6 hours in the level of IL-6 mRNA after the treatment with HSP70 of 30 mg/L,and 12 hours in the level of supematant IL-6 protein.Decreased supernatant IL-6 protein and IL-6 mRNA were noted for PFbs treated with PDTC and HSP70 of 30 mg/L compared with untreated PFbs((42.23 ± 9.41)ng/L vs.(68.40 ± 14.43)ng/L,0.144 ± 0.048 vs.0.295 ± 0.081,both P ＜ 0.05).Conclusion HSP70 may increase the expression of IL-6 mRNA and protein by cultured PFbs via the nuclear factor-kappa B pathway. Key words: Psoriasis; HSP70 heat-shock proteins; Fibroblasts; Interleukin-6