Uterine NK Cells Mediate Inflammation-Induced Fetal Demise in IL-10-Null Mice This information is current as Shaun P. Murphy, Loren D. Fast, Nazeeh N. Hanna and of September 27, 2021. Surendra Sharma J Immunol 2005; 175:4084-4090; ; doi: 10.4049/jimmunol.175.6.4084 http://www.jimmunol.org/content/175/6/4084 Downloaded from References This article cites 52 articles, 13 of which you can access for free at: http://www.jimmunol.org/content/175/6/4084.full#ref-list-1 http://www.jimmunol.org/ Why The JI? Submit online. • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication by guest on September 27, 2021 *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2005 by The American Association of Immunologists All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology Uterine NK Cells Mediate Inflammation-Induced Fetal Demise in IL-10-Null Mice Shaun P. Murphy,* Loren D. Fast,† Nazeeh N. Hanna,‡ and Surendra Sharma2* Specialized NK cells are recruited in high numbers to the mammalian embryo implantation sites, yet remain pregnancy com- patible. It is not well understood whether uterine NK (uNK) cells become adversely activated and mediate fetal demise, a common complication of early pregnancy. In this study we show that mating of IL-10؊/؊ mice resulted in fetal resorption or intrauterine growth restriction in response to very low doses of LPS. Pregnancy in congenic wild-type mice was normal even at 10-fold higher LPS doses. Fetal resorption in IL-10؊/؊ mice was associated with a significant increase in uNK cell cytotoxic activation and invasion into the placenta. Depletion of uNK cells, TNF-␣ neutralization, or IL-10 administration rescued pregnancy in LPS- treated IL-10؊/؊ animals. Our results identify an immune mechanism of fetal demise involving IL-10 deficiency, NK cells, and inflammation. These results may provide insight into adverse pregnancy outcomes in humans. The Journal of Immunology, 2005, Downloaded from 175: 4084–4090. pproximately half of all human blastocyst implantations populations of macrophages, T cells, and other immune cells in the result in failed pregnancy. Multiple factors may contrib- uterus during early stages of pregnancy (11). These cells populate A ute to this failure, including genetic and developmental the uterus after implantation in mice and during the proliferative anomalies of the embryo. However, many cases of pregnancy fail- stage of the menstrual cycle in humans, where they increase in http://www.jimmunol.org/ ure are thought to be associated with maternal immune-mediated number until midgestation. Thereafter, their numbers decline rap- mechanisms. A successful pregnancy is marked by an intricate idly (11, 12). Most studies to date have shown a pregnancy-com- regulation of the immune system at the maternal-fetal interface, patible role for uNK cells in reproduction, mainly through their resulting in tolerance of the semiallogeneic fetus (1–3). It is be- regulation of decidualization, production of pregnancy-compatible lieved that disruptions in this regulation may result in pregnancy cytokines, and cross-talk with the trophoblast. During pregnancy, failures. In this context, an array of factors may impel the maternal NK cell-deficient mice display abnormalities in decidual artery immune system toward antifetal responses. Indeed, infection and remodeling and trophoblast invasion, possibly due to the lack of other inflammatory insults are associated with a host of pregnancy uNK cell-derived IFN-␥ (13–16). In humans, it has been suggested complications in humans (4, 5). that defective trophoblast invasion and placental development are by guest on September 27, 2021 The maternal-fetal interface constitutes a unique environment associated with altered uNK cell function and preeclampsia (17, for innate and adaptive immune responses (6, 7). However, the 18). Curiously, although uNK cells display an activated phenotype implanted embryo and developing fetus during normal pregnancy (19, 20), to date, no in vivo role for uNK cell cytotoxicity has been are capable of suppressing these immune responses (8). There also identified. It is tempting to propose that although uNK cells nor- appear to be pregnancy-compatible alterations in the maternal im- mally contribute to the success of pregnancy, they may exert a mune system that protect against a graft-vs-host reaction from the negative role given aberrant intrauterine conditions. fetal immune system (8). However, aberrant immune regulation For the most part, tolerogenic processes that control the maternal may result in adverse pregnancy outcomes. In mice, disruptions in immune system and protect the fetus are probably local and temporal T cell regulation have been shown to result in immune-mediated at the maternal-fetal interface. The search for components of the in- loss of the fetal allograft (9, 10). In normal pregnancy, no adverse trauterine milieu that contribute to successful pregnancy outcome and immune responses are mounted despite the presence of high num- control detrimental innate and adaptive inflammatory immune re- 3 bers of uterine NK (uNK) cells (up to 65–70%) as well as smaller sponses has implicated cytokines, neuroendocrine immunomodula- tors, complement regulators, and nutrition-based factors (9, 21, 22). Among cytokines, the anti-inflammatory cytokine IL-10 is especially † *Departments of Pediatrics and Pathology, Women and Infants’ Hospital, and De- attractive for a critical role in pregnancy because of its regulatory partment of Medicine, Rhode Island Hospital-Brown University, Providence, RI 02905; and ‡Division of Neonatology, University of Medicine and Dentistry of New relationship with other intrauterine modulators and its wide range of Jersey-Robert Wood Johnson Medical School, New Brunswick, NJ 08903 immunosuppressive activities (23). Significantly, its local production Received for publication May 27, 2005. Accepted for publication July 11, 2005. by gestational tissues is well documented (24–26). We observed that The costs of publication of this article were defrayed in part by the payment of page IL-10 expression by the human placenta was gestational age depen- charges. This article must therefore be hereby marked advertisement in accordance dent, with significant expression through the second trimester coupled with 18 U.S.C. Section 1734 solely to indicate this fact. with attenuation at term (26). IL-10 expression was also found to be 1 This work was supported by National Institutes of Health Grants HD41701 and P20RR018728 (to S.S.). poor in decidual and placental tissues from unexplained spontaneous 2 Address correspondence and reprint requests to Dr. Surendra Sharma, Department abortion cases (27) and from deliveries associated with preterm labor of Pediatrics, 101 Dudley Street, Women and Infants’ Hospital of Rhode Island, and pre-eclampsia (our unpublished observations). However, the Providence, RI 02905. E-mail address: [email protected] mechanism(s) by which IL-10 protects the fetus remains poorly un- 3 Abbreviations used in this paper: uNK, uterine NK; DB, deciduas basalis; gd, ges- derstood. Although IL-10Ϫ/Ϫ mice suffer no pregnancy defects when tational day; IUGR, intrauterine growth restriction; MMP, matrix metalloproteinase; NRS, nonimmune rabbit serum; P, placental labyrinth; PAS, periodic acid-Schiff; mated under pathogen-free conditions (28), these mice eventually de- UMC, uterine mononuclear cell. velop colitis and fail to control intrinsic inflammatory responses (29, Copyright © 2005 by The American Association of Immunologists, Inc. 0022-1767/05/$02.00 The Journal of Immunology 4085 30). It is then plausible that in addition to IL-10 deficiency, an un- the supernatant from target cells lysed with 1 N HCl. The flow cytometry- regulated inflammatory insult resulting from genital tract infections, based cytotoxicity assay was performed according to the manufacturer’s Ј environmental factors, and/or hormonal anomalies during gestation protocol (Molecular Probes). Briefly, target cells were treated with 3,3 - dioctadecyloxacarbocyanine for 20 min at 37°C. Effector cells were mixed may lead to adverse pregnancy outcomes. with target cells as described above, and propidium iodide was added to A likely potential mechanism for IL-10-mediated protection of effector/target cell cultures, which were incubated for2hat37°C in 10% pregnancy is through direct action on decidual immune cells. In CO2. Cellular events were then immediately acquired on a flow cytometer. this study we demonstrate a novel regulatory relationship among Histochemistry IL-10 deficiency, inflammation, enhanced uNK cell activity, and pregnancy loss. Exposure of IL-10Ϫ/Ϫ, but not wild-type, mice to Individual, intact utero-placental units were isolated and fixed with 10% low doses of LPS provokes vigorous uNK cell cytotoxicity and buffered formalin for 24 h. Tissue was processed for histological staining with hematoxylin and periodic acid-Schiff reagent