The inten sity indices for IL 8 were 0. 17 for the control, 0. 52 for Paclitaxel solubility IL 1 alone, 0. 20 for epinephrine alone, and 0. 64 for IL 1 plus epinephrine. The results with IL 13 expression showed the same pattern. IL 1 was a good inducer of IL 13 transcription while epinephrine alone only minimally induced IL 13 mRNA. The combined stimulus of IL 1 and epinephrine significantly increased IL 13 mRNA pro duction over that seen with each stimulus alone. RT PCR neously with IL 1 into the cultures, the production of IL 6 was enhanced significantly compared with that induced by IL 1 alone. Since the physiolog ical concentration of epinephrine in plasma is 0. 11 0. 27 10 6 M, we decided to use epinephrine at a supramaximal concentration of 1 10 5 M for the rest of the experiments.
In addition to IL 6, the enhancing effect of epinephrine was also observed in the production of IL 8 and IL 13 from IL 1 induced HMC 1 cells. To measure proatherogenic cytokine gene expression, HMC 1 were treated with IL 1, epinephrine, and IL 1 plus epinephrine for 6 hours and harvested for transcrip tional analysis via RT PCR. IL 1 treated HMC 1 showed increased IL 6 mRNA transcription as seen with densitom etry, while epinephrine alone appeared to have no effect. When IL 1 and epinephrine were added together to HMC 1, IL 6 mRNA expression increased over IL 1 treat ment alone. The intensities of the cytokine and house keeping gene bands were measured by den sitometry, and the ratio of the cytokine to the house keep Intensity indices for IL 13 were 0. 22 for the control, 0. 57 for IL 1 alone, 0.
20 for epinephrine alone, and 0. 64 for IL 1 plus epinephrine. To evaluate further the ability of epinephrine to induce IL 13 transcription at a molecular level, we transiently transfected HMC 1 cells with mini mal promoter sequences as described in the materials and methods. IL 1 at 10 ng ml significantly increased IL 13 promotor activity as detected by luciferase expression. Epinephrine did not enhance IL 13 promoter activity suggesting that post transcriptional mechanisms may be involved in the IL 13 induction. It is likely that epinephrine either prolongs IL 13 mRNA half life and or enhances IL 13 secretory processes from the mast cell in response to IL 1 stimulation.
Enhancing effect of epinephrine on proatherogenic cytokine production from IL 1 induced HMC 1 is down regulated Batimastat by adrenoceptor antagonists Since our previous study has shown that the effect of epinephrine on nitric oxide synthesis is mediated by adrenoceptors, adrenergic receptor antagonists were used to block the enhancing effect of epinephrine on proatherogenic cytokine production in HMC 1. Propranolol and atenolol at a concentration of 1 10 4 M did not affect the cell viability in the cultures, nor induced production of IL 6, IL 8 or IL 13. When propranolol at 1 10 4 and 1 10 5 M was used in the culture, it significantly reduced the enhancing effect of epinephrine on IL 6 production.