FIGURE 4.

(A) Induction of IL-6 and IL-8 gene expression in TRPV1-overexpressing cells by capsaicin and inhibition by LJO-328. Cells were treated as shown in the figure for 4 h, harvested, and changes in gene expression assessed by RT-PCR, as described under the materials and methods section. (*) Represents a statistical increase over untreated control cells while (#) represents significant differences from treated and control cells. (B) The effects of multiple TRPV1 antagonists and modulators of TRPV1 function or calcium concentration on the induction of IL-6 (open bars) and IL-8 (shaded bars) genes in TRPV1-overexpressing cells treated with capsaicin (1 μM) for 4 h at 37°C. Concentrations of antagonist were SC0030 (100 nM), capsazepine (15 μM), EGTA (75 μM), and ruthenium red (150 μM). Points at which statistically greater levels of gene expression were observed versus untreated control cells are indicated by an asterisk (*), while lower levels of expression relative to capsaicin-treated cells are represented with an open circle (°). Data represent the mean and standard deviation (n = 5). (C) Inhibition of capsaicin- and RTX-induced IL-6 secretion by TRPV1-overexpressing cells with LJO-328. Cells were treated with increasing concentrations of LJO-328 and capsaicin (1 μM) (squares) or RTX (10 nM) (triangles) for 24 h at 37°C. IL-6 concentration in media was determined by ELISA using pooled samples (n = 3). The concentration of IL-6 in untreated control cells was ~265 pg/mL.