Effect of protein kinase C on signal transduction in antigen activated mast cells / 第二军医大学学报

ABSTRACT

Objective: To investigate the effect of protein ki nase C on signal transduction such as tyrosine phosphorylation, c-fos and c-ju n mRNA expression in antigen activated mast cells. Methods: RBL-2H3 cells either untreated or treated with phorbol 12-myristate 13 -acetate (PMA) were sensitized with anti-DNP IgE, and activated with DNP-BSA, histamine release and tyrosine phosphorylation were quantitatively measured by ELISA and flow cytometry, respectively. The effect of PKC on the ex pression of c-fos and c-jun in serum-deprived RBL-2H3 cells activated by DNP-BSA detected by ethidium staining of PCR-amplified cDNA, the amplified cDNA products were subjected to Southern blot hybridization using specific prob es to determine the veracity of amplification. Results: Tyr osine phosphorylation and histamine release were significantly reduced from (4.4 7±0.03)% to (2.79±0.07)% and (104.47±1.31) nmol/L to (60.75±1.38) nm ol/L, respectively, 45 min after DNP-BSA stimulation in sensitized cells pre treated with PMA for 48 h. Bands of the size predicted for the amplified cDNA we re obtained 299 bp for c-fos, and 651 bp for c-jun, a decrease of 91% and 82% , respectively, for c-fos and c-jun mRNAs was observed in antigen stimulated c ells pretreated with PMA for 48 h. Conclusion: PKC plays an impo rtant role in modulating the tyrosine phosphorylation and histamine release resp onses and may upregulate the expression of c-fos and c-jun in antigen activate d mast cell.