isolation-leukocytes-from-murine-tissues-at-maternal-fetal

Isolation of Leukocytes from the Murine Tissues at the Maternal-Fetal Interface

Immune tolerance in pregnancy requires that the immune system of the mother undergoes distinctive changes in order to accept and nurture the developing ...

Wayne State University School of Medicine

The human labor is an inflammatory process invading leukocytes modulated by gestational tissues. The local increase of cell adhesion molecules (CAMs) promotes the permanence of these leukocytes in the coriodecidua. Gestational tissues express ICAM-1, while circulating leukocytes expressing its ligand Mac-1.

[Expression of cell adhesion molecules in the maternal fetal period of human gestation].

Intrauterine infection during pregnancy can trigger a local inflammatory response leading to several complications, such as preterm labor. Many studies have used in vitro and in vivo models employing mitogens to induce the expression of the characteristic proinflammatory mediators triggered by infection. However, relative expression assays depend on the stability of housekeeping gene expression, which can vary depending on certain stimuli. In this study, we analyzed the stability and pairwise variation in the expression of GAPDH, ACTB and RNA18S1 in cultured reproductive tissues under mitogen stimulation. We used fetal membranes, placental villous and umbilical cord explants from patients with normal term pregnancies (>37 weeks of gestation), as well as myometrium and cervix explants from patients undergoing hysterectomies. Tissues were stimulated with lipopolysaccharide or phytohemagglutinin for 24 hours. We then analyzed the expression stability and the pairwise variation of GAPDH, ACTB and RNA18S1 from real time quantitative RT-PCR absolute threshold cycles (Cp) using geNorm software.

Housekeeping gene expression stability in reproductive tissues after mitogen stimulation.

Labor resembles an inflammatory response that includes secretion of cytokines/chemokines by resident and infiltrating immune cells into reproductive tissues and the maternal/fetal interface. Untimely activation of these inflammatory pathways leads to preterm labor, which can result in preterm birth. Preterm birth is a major determinant of neonatal mortality and morbidity; therefore, the elucidation of the process of labor at a cellular and molecular level is essential for understanding the pathophysiology of preterm labor. Here, we summarize the role of innate and adaptive immune cells in the physiological or pathological activation of labor. We review published literature regarding the role of innate and adaptive immune cells in the cervix, myometrium, fetal membranes, decidua and the fetus in late pregnancy and labor at term and preterm. Accumulating evidence suggests that innate immune cells (neutrophils, macrophages and mast cells) mediate the process of labor by releasing pro-inflammatory factors such as cytokines, chemokines and matrix metalloproteinases. Adaptive immune cells (T-cell subsets and B cells) participate in the maintenance of fetomaternal tolerance during pregnancy, and an alteration in their function or abundance may lead to labor at term or preterm. Also, immune cells that bridge the innate and adaptive immune systems (natural killer T (NKT) cells and dendritic cells (DCs)) seem to participate in the pathophysiology of preterm labor. In conclusion, a balance between innate and adaptive immune cells is required in order to sustain pregnancy; an alteration of this balance will lead to labor at term or preterm.

Immune cells in term and preterm labor.

Is increased leukocyte chemotactic activity (CA) from gestational tissues necessary for term or preterm labor in guinea pigs?

Chemotactic activity of gestational tissues through late pregnancy, term labor, and RU486-induced preterm labor in Guinea pigs.

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality worldwide. A transition from an anti-inflammatory state to a pro-inflammatory state in the mother and at the maternal-fetal interface has been implicated in the pathophysiology of microbial-induced preterm labor. However, it is unclear which immune cells mediate this transition. We hypothesized that an imbalance between innate and adaptive immune cells at the maternal-fetal interface will occur prior to microbial-induced preterm labor. Using an established murine model of endotoxin-induced PTB, our results demonstrate that prior to delivery there is a reduction of CD4+ regulatory T cells (Tregs) in the uterine tissues. This reduction is neither linked to a diminished number of Tregs in the spleen, nor to an impaired production of IL10, CCL17, or CCL22 by the uterine tissues. Endotoxin administration to pregnant mice does not alter effector CD4+ T cells at the maternal-fetal interface. However, it causes an imbalance between Tregs (CD4+ and CD8+), effector CD8+ T cells, and Th17 cells in the spleen. In addition, endotoxin administration to pregnant mice leads to an excessive production of CCL2, CCL3, CCL17, and CCL22 by the uterine tissues as well as abundant neutrophils. This imbalance in the uterine microenvironment is accompanied by scarce APC-like cells such as macrophages and MHC II+ neutrophils. Collectively, these results demonstrate that endotoxin administration to pregnant mice causes an imbalance between innate and adaptive immune cells at the maternal-fetal interface.Cellular & Molecular Immunology advance online publication, 6 April 2015; doi:10.1038/cmi.2015.22.

Article	Year
[Expression of cell adhesion molecules in the maternal fetal period of human gestation]. Ginecología y obstetricia de México\| PubMed ID: 21961374	2010
Housekeeping gene expression stability in reproductive tissues after mitogen stimulation. BMC research notes\| PubMed ID: 23875991	2013
Immune cells in term and preterm labor. Cellular & molecular immunology\| PubMed ID: 24954221	2014
Chemotactic activity of gestational tissues through late pregnancy, term labor, and RU486-induced preterm labor in Guinea pigs. American journal of reproductive immunology (New York, N.Y. : 1989)\| PubMed ID: 25329235	2015
An imbalance between innate and adaptive immune cells at the maternal-fetal interface occurs prior to endotoxin-induced preterm birth. Cellular & molecular immunology\| PubMed ID: 25849119	2015

Marcia Arenas-Hernandez

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