[An experimental study on the regulation of the expression of Th2 cytokines by nuclear factor-kappaB and protein kinase C in asthma]

Abstract

Objective: To explore the role of nuclear factor-kappaB (NF-kappaB) in the signal pathway of protein kinase C (PKC) regulating the expression of Th2 cytokines, interleukin 4 (IL-4) and IL-5, by T lymphocyte in asthma.

Methods: 16 guinea pigs were randomly divided into 2 groups, normal control and asthmatic group. 16 asthmatic patients and 16 normal control persons also participated in the study. T lymphocytes were isolated and purified from blood of each guinea pig and each person and divided into 3 groups: cells of 1st group were control group, cells of 2nd group were stimulated with phorbol 12-myristate 13-acetate (PMA), cells of 3rd group were stimulated with PMA and pyrrolidine dithiocarbamate (PDTC). The expression of NF-kappaB were observed by immunocytochemical staining, the expression of IL-4 and IL-5 mRNA were observed by in situ hybridization staining, IL-4 and IL-5 protein in supernatants were measured by ELISA.

Results: The percentage of cells of active NF-kappaB, the percentage of positive cells of IL-4 and IL-5 mRNA, IL-4 and IL-5 protein in supernatants of asthmatic T lymphocyte stimulated with PMA were significantly higher than those of asthmatic T lymphocyte stimulated without PMA (q = 8.44 approximately 38.66, P < 0.01) and those of normal control T lymphocyte stimulated with PMA (q = 8.11 approximately 40.12, P < 0.01), and were significant reduced by PDTC (q = 6.50 approximately 35.63, P < 0.01). There were good positive correlation between the percentage of cells of active NF-kappaB and the percentage of positive cells of IL-4 and IL-5 mRNA (r = 0.60 approximately 0.82, P < 0.001, respectively), and also good positive correlation between the percentage of active NF-kappaB and IL-4 and IL-5 protein in supernatants (r = 0.42 approximately 0.70, P < 0.005 or < 0.001, respectively).

Conclusions: The active PKC of asthmatic T lymphocyte increasing the expression of IL-4 and IL-5 may be mediated by activating NF-kappaB, the activation of PKC-NF-kappaB signal pathway of T lymphocyte NF-kappab may play an important role in the pathogenesis of asthma.