Escherichia coli-induced temporal and differential secretion of heat- shock protein 70 and interleukin-1b by human fetal membranes in a two-compartment culture system M. Osorio-Caballero a , C. Perdig  on-Palacio b , G. García-L  opez c , O. Flores-Herrera d , S. Olvera-S  anchez d , I. Morales-M  endez e , I. Sosa-Gonz  alez e , J.F. Acevedo f , A.M. Guzm  an-Grenfell b , A. Molina-Hern  andez c , N.F. Díaz c , H. Flores-Herrera b, * a Department of Obstetrics and Gynecology, National Institute of Perinatology “Isidro Espinosa de los Reyes”, Montes Urales #800, Col. Lomas de Virreyes cp, 11000 Mexico City, Mexico b Department of Biochemistry and Molecular Biology, National Institute of Perinatology “Isidro Espinosa de los Reyes”, Mexico City, Mexico c Department of Cellular Biology, National Institute of Perinatology “Isidro Espinosa de los Reyes”, Mexico City, Mexico d Department of Biochemistry, School of Medicine, UNAM. Apdo. Postal 70-159, Copilco, Coyoac an, Mexico City, Mexico e Department of Infectology and Immunology, National Institute of Perinatology “Isidro Espinosa de los Reyes”, Mexico City, Mexico f Department of Obstetrics and Gynecology, University of Texas SouthWestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75235, USA article info Article history: Accepted 15 December 2014 Keywords: Amnion Choriodecidual Chorioamnionitis Escherichia coli Heat-shock protein Interleukin-1b abstract Introduction: Escherichia coli is recognized as an etiological bacteria associated with chorioamnionitis and the preterm premature rupture of fetal membranes. This pathological condition induces pro- inflammatory cytokines and degradative metalloproteinases, which are considered biological markers secreted in an acute stage of infection. Heat-shock proteins (HSPs) are an important component of the innate immunity response and are found in different pathological conditions. They have not been pre- viously measured in human fetal membranes in response to infectious conditions. We hypothesized that the choriodecidual tissue and amniotic epithelium secreted temporal and differential Hsp-60, Hsp-70, and interleukin (IL)-1b mediated by E. coli infection. Methods: Fetal membranes were mounted in a two-compartment culture system and infected with two passes of live E. coli at different doses (10 2 , 10 4 , 10 5 , and 10 6 colony-forming units (CFU)/mL) and intervals of incubation (3, 6, and 24 h). The culture medium was collected, and Hsp-60, Hsp-70, and IL-1b were assessed using the enzyme-linked immunosorbent assay (ELISA) method. Results: After 3 and 6 h of infection, E. coli induced an increase in Hsp-70 secretion in the choriodecidual tissue. However, after 24 h of incubation, Hsp-70 was downregulated and we observed an increase in IL- 1b secretion. By contrast, E. coli induced a lower Hsp-60 secretion in the amnion compared to Hsp-70. Discussion: Human fetal membranes responded actively to E. coli infection, with an increase in Hsp-70 during the first hours of infection. After 24 h, there was an increase in the liberation of IL-1b. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Intrauterine infections are major etiological factors associated with preterm delivery (PTD) and premature rupture of the fetal membranes (PROM), and they predispose the neonate to a higher risk of intra-amniotic infection [1]. The early pathogenesis stages of intrauterine infections are not completely understood. However, much evidence has shown that fetal membranes actively respond to acute infection by secreting pro-inflammatory cytokines (inter- leukin (IL)-1b and IL-8); tumor necrosis factor alpha (TNF-a); che- mokines (IL-8, monocyte chemotactic protein-1, and macrophage inflammatory protein-1) [2e4]; and degradative matrix metal- loproteinases (MMP)-2, MMP-3, and MMP-9 [5,6]. These molecules are considered biological markers. Through these pro- inflammatory/degradative processes, the structure, stability, and * Corresponding author. Department of Biochemistry and Molecular Biology, National Institute of Perinatology “Isidro Espinosa de los Reyes”, Montes Urales #800, Col. Lomas de Virreyes cp, 11000 Mexico City, Mexico. Tel./fax: þ52 55 55209705. E-mail address: h.flores@inper.mx (H. Flores-Herrera). Contents lists available at ScienceDirect Placenta journal homepage: www.elsevier.com/locate/placenta http://dx.doi.org/10.1016/j.placenta.2014.12.011 0143-4004/© 2014 Elsevier Ltd. All rights reserved. Placenta 36 (2015) 262e269