Effects of endogenous substance P expression on degranulation in RBL-2H3 cells

Abstract

To determine whether RBL-2H3 cells have endogenous substance P (SP) expression under immunoglobulin E (IgE)-activated and inactivated conditions, and to ascertain the function of endogenous SP in the antigen-induced degranulation of RBL-2H3 cells. SP mRNA and protein expression in both inactivated and 2,4-dinitrophenol (DNP)-specific IgE-activated RBL-2H3 cells were assessed by real-time PCR and immunofluorescence, respectively. Following activation with DNP-specific IgE, the degranulation of RBL-2H3 cells in response to DNP-bovine serum albumin (BSA), with and without endogenous SP expression, was assessed by monitoring the release of the granular enzyme β-hexosaminidase. Endogenous SP mRNA and peptide expression increased in activated RBL-2H3 cells, compared with inactivated RBL-2H3 cells. The small hairpin RNA (shRNA)-mediated knockdown of endogenous SP reduced the degranulation ability of RBL-2H3 cells. Activated RBL-2H3 cells express endogenous SP which plays a role in antigen-induced degranulation.