The chemokine receptor CCR2 is not required for successful initiation of labor in mice

Menzies, F. M., Khan, A. H., Higgins, C. A., Nelson, S. M. and Nibbs, R. J. B. (2012) The chemokine receptor CCR2 is not required for successful initiation of labor in mice. Biology of Reproduction, 86(4), p. 118. (doi:10.1095/biolreprod.111.094631)

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Publisher's URL: http://dx.doi.org/10.1095/biolreprod.111.094631

Abstract

Chemokine-driven neutrophil and monocyte recruitment into the uterus and cervix has been proposed to initiate labor. Chemokines that bind CXCR2 direct neutrophil migration and are induced during labor in humans. The chemokine CCL2, induced in the uterus by endocrine and mechanical signals, has been proposed to drive CCR2-dependent monocyte homing to the uterus to contribute to the initiation of labor. However, no direct evidence indicates that chemokines or their receptors play indispensable roles in labor-associated inflammation, and the impact of leukocyte infiltration on labor is unclear. Here, we have quantified expression of the principal monocyte- and neutrophil-attracting chemokines in the uteri of term pregnant (Day 18) and laboring wild-type mice. None of the neutrophil attractants we assayed were up-regulated with labor. Strikingly, however, Ccl2 was markedly increased, and this was concomitant with increased expression of Ccr2, the myeloid marker Itgam (also known as Cd11b), the monocyte/macrophage marker Emr1 (also known as F4/80). Moreover, in CCR2-deficient mice, this labor-associated increase in Itgam and Emr1 was not seen, consistent with the monocyte-trafficking defects that exist in these animals. Nonetheless, laboring CCR2-deficient and wild-type uteri showed similarly enhanced expression of the myometrial activation markers Gja1 and Oxtr (commonly known as connexin 43 and oxytocin receptor, respectively), and CCR2-deficient mice had gestation lengths, litter sizes, and fetal and placental weights no different from those of their wild-type counterparts. Thus, whereas labor is associated with an inflammatory response in gestational tissues, CCR2-dependent leukocyte recruitment into the mouse uterus is dispensable for the initiation of successful labor.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Menzies, Dr Fiona and Nelson, Professor Scott and Higgins, Dr Claire and Nibbs, Professor Robert
Authors: Menzies, F. M., Khan, A. H., Higgins, C. A., Nelson, S. M., and Nibbs, R. J. B.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cancer Sciences
College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
Journal Name:Biology of Reproduction
ISSN:0006-3363
ISSN (Online):1529-7268
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