The American Journal of Pathology, Vol. 179, No. 6, December 2011 Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved. DOI: 10.1016/j.ajpath.2011.08.029 Biomarkers, Genomics, Proteomics, and Regulation

Prokineticin 1 Induces Inflammatory Response in Human Myometrium

A Potential Role in Initiating Term and Preterm Parturition

Marta R. Gorowiec,*† Rob D. Catalano,* Human parturition is a pro-inflammatory event associated Jane E. Norman,† Fiona C. Denison,† and with the influx of leukocytes, such as neutrophils and 1,2 Henry N. Jabbour* macrophages, to the uterus. Indeed, 40% to 60% of up-regulated in the myometrium and cervix at la- From the Medical Research Council Human Reproductive bor are involved in inflammation and chemotaxis.3 Re- Sciences Unit * and Reproductive and Developmental cruited leukocytes secrete cytokines, including IL-1␤, † Sciences, The Queen’s Medical Research Institute, Edinburgh, 4 IL-6, and IL-8, and E2 (PGE2) and F2␣ United Kingdom (PGF2␣). These cytokines and prostaglandins can stimu- late production of matrix metalloproteinases that are in- volved in membrane rupture5 and can also promote cer- vical ripening.6 However, during labor, the greatest influx The infiltration of human myometrium and cervix of leukocytes is observed in the myometrium.1 Cytokines, with leukocytes and the formation of a pro-inflam- such as IL-1␤, released by leukocytes, promote the syn- matory environment within the uterus have been thesis of synthase 2 (PTGS2)–dependent associated with the initiation of both term and pre- prostaglandins (PGE2 and PGF2␣), which are important term parturition. The mechanism regulating the on- regulators of myometrial contractility.7,8 More important, set of this pro-inflammatory cascade is not fully independently of prostaglandins, IL-1␤ also regulates elucidated. We demonstrate that prokineticin 1 basal and store-operated calcium entry in myometrial (PROK1) is up-regulated in human myometrium cells, which is important for contractions and during labor. The expression of of individual smooth muscle cells.9 PROK1 receptor remains unchanged during labor The same pro-inflammatory events can be initiated and is abundantly expressed in the myometrium. before 37 weeks of gestation and lead to premature onset Gene array analysis identified 65 genes up-regu- of parturition and preterm birth. Nearly 11% of all single- lated by PROK1 in human myometrium, mainly cy- ton deliveries are preterm, and this constitutes the big- tokines and chemokines, including IL-1␤, chemo- gest cause of neonatal morbidity and mortality.10,11 Al- kine C-C motif ligand 3, and colony-stimulating though several factors, such as smoking, alcohol, factor 3. In addition, we demonstrate that PROK1 advanced maternal age, and structural abnormalities of 12,13 increases the expression of chemokine C-C motif the cervix, can contribute to preterm initiation of la- ligand 20, IL-6, IL-8, prostaglandin synthase 2, and bor, bacterial infection in the uteroplacental unit is be- lieved to be a major cause. Such infections are detected prostaglandin E2 and F2␣ secretion. The treatment of myometrial explants with 100 ng/mL of lipopoly- in 79% of births at 23 weeks and in 11% of births at 31 to 14,15 saccharide up-regulates the expression of PROK1, 34 weeks. In most cases of preterm birth, even in the PROK1 receptor, and inflammatory mediators. The infection of myometrial explants with lentiviral mi- Supported by the Medical Research Council, Piggy Bank Kids. croRNA targeting PROK1, preceding treatment with Accepted for publication August 18, 2011. lipopolysaccharide, reduces the expression of in- M.R.G. and R.D.C. contributed eq