BOR - Papers in Press, published online ahead of print
December 11, 2002.
Biol Reprod 2002, 10.1095/biolreprod.102.011403
BIOLOGY OF REPRODUCTION 68, 18421849 (2003)
DOI: 10.1095/biolreprod.102.011403
© 2003 by the Society for the Study of Reproduction, Inc.
Interleukin-1ß Induces Calcium Transients and Enhances Basal and Store Operated Calcium Entry in Human Myometrial Smooth Muscle1
Rachel M. Tribe2,3,
Patrick Moriarty3,
Annette Dalrymple3,
Abdul A. Hassoni4, and
Lucilla Poston3
Parturition Research, Maternal and Fetal Research Unit,3
Department of Women's Health, Centre for Cardiovascular Biology and Medicine,4 King's College London, St. Thomas' Hospital Campus, London SE1 7EH, United Kingdom
We have previously reported increased protein expression of sarcoplasmic reticulum calcium ATPase (SERCA) 2b in myometrium from women in labor at term, but the stimulus for this change is unknown. Proinflammatory cytokines have been implicated in the cascade of events leading to preterm and term labor, and we hypothesize that interleukin (IL)-1ß may induce changes in key calcium homeostatic mechanisms and, in turn, augment myometrial contractility before labor. The aim of the present study was to investigate the long-term effects of IL-1ß on SERCA 2b protein expression, calcium mobilization from intracellular stores, and store-operated calcium entry. Myometrial biopsies were obtained, with consent, from women undergoing elective cesarean section at term. Primary-cultured human myometrial smooth muscle (HMSM) cells were exposed to IL-1ß (10 ng/ml) for 24 h or to culture medium alone (control). Cells were subsequently used in Western blot studies or loaded with fura-2 to assess calcium dynamics using fluorescent digital imaging. The present study clearly demonstrated that IL-1ß significantly increased SERCA 2b protein expression in HMSM cells. Cyclopiazonic acid-induced calcium transients were also augmented, predominantly by activation of lanthanum-sensitive, store-operated calcium entry. HMSM cell excitability was enhanced, as evidenced by increased basal calcium entry and the initiation of spontaneous calcium transients in 37% of IL-1ß-treated cells. IL-1ß modulation of calcium mobilization may be an important mechanism in the cascade of events preparing the pregnant uterus for labor.
1 Supported by a grant from The Wellcome Trust (no. 061138) and Tommy's, the baby charity (reg. charity no. 1060508).
2 Correspondence: R.M. Tribe, Parturition Research, Maternal and Fetal Research Unit, Department of Women's Health, Guy's, King's and St. Thomas' School of Medicine, St. Thomas' Hospital Campus, London SE1 7EH, U.K. FAX: 44 020 7620 1227; rachel.tribe{at}kcl.ac.uk
Copyright © 2003 by the Society for the Study of Reproduction.