Effect of COX-2 inhibitor NS-398 on expression of PGE2 receptor subtypes in M-1 mouse CCD cells.. R Nasrallah; O Laneuville; S Ferguson; R L Hébert (2001) American journal of physiology. Renal physiology display abstract
Our present study has investigated the effect of cyclooxygenase-2 (COX-2) inhibition on prostaglandin E2 (PGE2) receptor expression in M-1 cortical collecting duct cells and measured their response to PGE2. Using a semiquantitative titration analysis method, we show that following the addition of the COX-2-specific inhibitor NS-398, E-prostanoid receptor subtype (EP3 and EP4) mRNA expression was found to increase threefold each vs. the vehicle-treated control. We also observed that EP1 but not EP2 is expressed in M-1 cells and EP2 levels are not induced by NS-398. To determine the status of the PGE2 response on exposure to NS-398, we measured cAMP levels in cells after stimulation with varying concentrations of PGE2, then pretreated the cells with 10 microM NS-398 before PGE2 exposure and found a significant rise in the stimulatory effect of PGE2 on cAMP production. Finally, Western blot analysis of the levels of the EP4 receptor protein in control vs. NS-398-treated cells revealed an induction in protein levels in these cells, correlating with the induction in EP4 mRNA. We conclude that NS-398 upregulates the expression of EP3 and EP4 mRNA in M-1 cells. Also, EP4 protein levels are increased, resulting in an increased stimulation of cAMP production by PGE2.
Cyclooxygenase 2-mediated suppression of macrophage interleukin-12 production after thermal injury.. Martin G Schwacha; Chun-Shiang Chung; Alfred Ayala; Kirby I Bland; Irshad H Chaudry (2002) American journal of physiology. Cell physiology display abstract
Macrophage (Mphi) prostaglandin (PG)E(2) production has been implicated in immunosuppression and increased susceptibility to sepsis after thermal injury. Deficient interleukin (IL)-12 production has also been implicated in these postburn complications. The present study examined the relationship between Mphi cyclooxygenase (COX)-2 activity and IL-12 production after thermal injury. C57BL/6 female mice were subjected to a 25% total body surface area full-thickness burn. Mphi were isolated 7 days later, or the mice were subjected to sepsis by cecal ligation and puncture (CLP). IL-12 production by Mphi from injured mice was suppressed by >50%, whereas COX-2 expression and PGE(2) production were increased twofold. The COX-2 inhibitor NS-398 suppressed PGE(2) production and normalized IL-12 production in the injury group, whereas it had no effect on IL-10 production. Injured mice subjected to CLP had lower IL-12 plasma levels compared with sham-treated mice subjected to CLP. NS-398 treatment prevented the suppression in plasma IL-12 levels in the injury group. Thus elevated Mphi COX-2 activity, independent of IL-10, suppresses Mphi IL-12 production after thermal injury and may play an important role in the observed immunosuppression under such conditions.