AJR11993: 30:49-57 Printed ill the United States ofAmerica - all rig/as reserved. Copyright ." Mlillksgallrd, /993 American Journal of Reproducth'e Immunologg ISSN 11755-11920 Cytokine-Initiated Signal Transduction in Human Myometrial Cells FRANK HERTELENDY, ROBERTO ROMERO, MIKLOS MOLNAR, HERBERT TODD, AND JOSEPH J, BALDASSARE Cvtokine-Initiated Signal Transduction in Human Myometrial Cells. Hertelendy F, Romero R, Molnar M, Todd H, Baldassare 11. A1R! /993: 30:49-57 ([) Munksgaard PROBLEM: The objectives of this study were to evaluate interleukin-I (lL-I) binding and some postreceptor actions of this cytokine and tumor necrosis factor (TN F) in human myome- trial cells (HMC), METHOD: Monolayer cultures of HMC were used to characterize binding and to measure cyclic (c)AMP. prostaglandin (PG)E 2 • and PGI 2 production. Membrane preparations were used to assess ADP-ribosylation and for immunoblotting. RESULTS: HMC were found to specifically bind [ 125I]IL-I with an apparent K, of 2 X 10- 10M. Incubation of HMC with IL-I or TNF caused a time-dependent and dose-dependent accumulation of cAMP. as well as a significant potentiation of forskolin-promoted cAMP pro- duction. These cytokines also increase PGE 2 and PGI 2 output. independently of the activation of adenylyl cyclase. IL-l treatment had no measurable effect either on cholera toxin-mediated and pertussis toxin-mediated ADP-ribosylati6n. or on the amount of G; proteins. as assessed by immunoblotting using a polyclonal antibody. CONCLUSIONS: It is suggested that IL-I and TNF may activate one or more isoforms of the catalytic component of adenylyl cyclase. raising intracellular cAMP. INTRODUCTION Interleukin (IL)-l and IL-6, as well as tumor necrosis factor (TNF), have been implicated as important mediators of preterm labor and parturition as- sociated with intrauterine infection. 1.2 The potent stimulatory effect of these cytokines on prostaglandin (PG) production by gestational tissues supports the hypothesis that an increased output of PGE 2 from the amnion and de- cidua plays a critical role in the initiation of premature labor, in the setting of intraamniotic infection. There is also evidence that the myometrium itself may be a target site of cytokines. 3 A recent study indicated that IL-I and TNF promote the release of eH]-arachidonic acid from human myometrial cell cultures in a time-dependent and dose-dependent fashion. This effect can be suppressed by cycloheximide, an inhibitor of protein synthesis, suggest- ing that these cytokines enhance the synthesis of phospholipase A 2 and pos- sibly other enzymes involved in arachidonic acid release. In turn, arachidonic Key words: IL-I receptors. cAMP. prostaglandin. forskolin, iloprost FRANK HERTELENDY Departments of Obstetrics and Gynecology and Pharmacological and Physiological Science. St. Louis University School of Medicine. St. Louis. Missouri ROBERTO ROMERO Wayne State University. Detroit. Michigan. and Perinatology Branch, NICHD. Bethesda. Maryland MIKLOS MOLNAR Department of Obstetrics and Gyneco- logy. St. Louis University School of Medicine. St. Louis. Missouri. and Institute of Pathophysiology. Sem- melweis Medical University. Budapest. Hungary HERBERT TODD Department of Obstetrics and Gynecology JOSEPHJ.BALDASSARE Department of Pharmacological and Physiological Science. St. Louis University School of Medicine. St. Louis. Missouri Presented at the 40th Annual Meeting of the Society for Gynecologic Investigation. Toronto. Canada. March 31-ApriI3. 1993. Submitted for publication June 9. 1993; accepted July 17. 1993. Address reprint requests to Frank Hertelendy. Ph.D .. D,Sc .. Department of Obstetrics & Gynecology. St. Louis University School of Medicine. 3635 Vista Avenue at Grand Blvd .. St. Louis. MO 63110-0250. AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY VOL. 30, 1993