The Effect of Misoprostol on Arachidonic Acid Mobilization, Prostaglandin E(2), Production, and IL-1beta Signaling.
The effect of misoprostol on interleukin-1beta (IL-1beta)-mediated phospholipid metabolism, arachidonic acid release, and prostaglandin E(2) (PGE(2)) production was examined using normal skin fibroblasts and synovial fibroblasts from patients with osteoarthritis. We found that both IL-1beta and misoprostol induced arachidonic acid release, suggesting enhanced phospholipase A(2) activation. Both Il-1beta and IL-1beta/misoprostol, but not misoprostol alone, induced a significant increase in PGE(2) levels compared with controls. Even though PGE(2) production was not significantly increased by misoprostol alone, misoprostol synergistically enhanced IL-1beta-mediated cyclooxygenase activity (sixfold to eightfold) and PGE(2) synthesis in normal fibroblasts but not in OA synovial fibroblasts. Additionally, misoprostol dramatically affected the arachidonate-labeling of triglyceride and cholesterol ester pools; the significance of this is as yet unclear. Together, the results suggest that misoprostol may upregulate the conversion of arachidonic acid to PGE(2) by enhancing the IL-1beta-induced activation/synthesis of cyclooxygenase.
Ballou
Leslie R.
LR
Department of Medicine, The University of Tennessee, Memphis USA, Department of Biochemistry, The University of Tennessee, Memphis USA, and Department of Veterans Affairs, Memphis, USA.
Postlethwaite
Arnold E.
AE
Kang
Andrew H.
AH