Inflammation-induced Preterm Birth Alters Neuronal Morphology in the Mouse Fetal Brain

Maternal and Child Health Research Program, Department of Obstetrics and Gynecology, Center for Research on Reproduction and Women's Health, University of Pennsylvania, Philadelphia, PA 19104-6142, USA.
Journal of Neuroscience Research (Impact Factor: 2.59). 07/2010; 88(9):1872-81. DOI: 10.1002/jnr.22368
Source: PubMed


Adverse neurological outcome is a major cause of long-term morbidity in ex-preterm children. To investigate the effect of parturition and inflammation on the fetal brain, we utilized two in vivo mouse models of preterm birth. To mimic the most common human scenario of preterm birth, we used a mouse model of intrauterine inflammation by intrauterine infusion of lipopolysaccharide (LPS). To investigate the effect of parturition on the immature fetal brain, in the absence of inflammation, we used a non-infectious model of preterm birth by administering RU486. Pro-inflammatory cytokines (IL-10, IL-1beta, IL-6 and TNF-alpha) in amniotic fluid and inflammatory biomarkers in maternal serum and amniotic fluid were compared between the two models using ELISA. Pro-inflammatory cytokine expression was evaluated in the whole fetal brains from the two models. Primary neuronal cultures from the fetal cortex were established from the different models and controls in order to compare the neuronal morphology. Only the intrauterine inflammation model resulted in an elevation of inflammatory biomarkers in the maternal serum and amniotic fluid. Exposure to inflammation-induced preterm birth, but not non-infectious preterm birth, also resulted in an increase in cytokine mRNA in whole fetal brain and in disrupted fetal neuronal morphology. In particular, Microtubule-associated protein 2 (MAP2) staining was decreased and the number of dendrites was reduced (P < 0.001, ANOVA between groups). These results suggest that inflammation-induced preterm birth and not the process of preterm birth may result in neuroinflammation and alter fetal neuronal morphology.

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Available from: Irina Burd, Apr 08, 2014
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    • "An intrauterine infection gaining access to the FMs is thought to trigger prematurity by activating innate immune responses (Romero et al., 2007). Indeed, clinical and experimental studies have correlated bacteria/bacterial components and inflammation at the maternal–fetal interface with preterm birth (Elovitz and Mrinalini, 2004; Elovitz et al., 2006; Romero et al., 2006; Pettker et al., 2007; Koga et al., 2009; Pirianov et al., 2009; Burd et al., 2010; Cardenas et al., 2011). However, in spite of this association, no single bacterium has been attributed to preterm birth, and antibiotic interventions have proved unsuccessful (Ganu et al., 2012). "
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    ABSTRACT: There has been growing interest in the role of viral infections and their association with adverse pregnancy outcomes. However, little is known about the impact viral infections have on the fetal membranes (FM). Toll-like receptors (TLR) are thought to play a role in infection-associated inflammation at the maternal-fetal interface. Therefore, the objective of this study was to characterize the cytokine profile and antiviral response in human FMs exposed to viral dsRNA, which activates TLR3, and viral ssRNA, which activates TLR8; and to determine the mechanisms involved. The viral dsRNA analog, Poly(I:C), induced upregulated secretion of MIP-1α, MIP-1β, RANTES and TNF-α, and downregulated IL-2 and VEGF secretion. In contrast, viral ssRNA induced a broader panel of cytokines in the FMs by upregulating the secretion of IL-1β, IL-2, IL-6, G-CSF, MCP-1, MIP-1α, MIP-1β, RANTES, TNF-α and GRO-α. Using inhibitory peptides against TLR adapter proteins, FM secretion of MIP-1β and RANTES in response to Poly(I:C) was MyD88-dependent; MIP-1α secretion was dependent on MyD88 and TRIF; and TNF-α production was independent of MyD88 and TRIF. Viral ssRNA-induced FM secretion of IL-1β, IL-2, IL-6, G-CSF, MIP-1α, RANTES and GRO-α was dependent on MyD88 and TRIF; MIP-1β was dependent upon TRIF, but not MyD88; and TNF-α and MCP-1 secretion was dependent on neither. Poly(I:C), but not ssRNA, induced a FM antiviral response by upregulating the expression of inflammasome components, IFNβ, MxA, OAS and APOBEC3G. These findings demonstrate that human FMs respond to two viral signatures by generating distinct inflammatory cytokine/chemokine profiles and antiviral responses through different mechanisms.
    Preview · Article · Apr 2014 · Molecular Human Reproduction
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    • "Antenatal infection has been linked to white matter damage and cerebral palsy; in babies born within one hour of membrane rupture (with low risk of infection subsequent to the rupture) whose placentas had histologic chorioamnionitis, the presence of leukocytes in the umbilical cord and chorionic plate were associated with an eleven-fold increase in the risk of white matter damage [73]. Studies involving mice show that inflammation-induced preterm birth caused neuropathology in the fetal brains, but not in preterm mice induced by a non-inflammatory method, indicating that it is not the process of preterm birth that affects neuronal morphology [74]. In this study, gestational day 15.5 mice were given an intraperitoneal injection of LPS with or without silibinin and compared to a basal group. "
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    ABSTRACT: Infection-induced preterm birth is the largest cause of infant death and of neurological disabilities in survivors. Silibinin, from milk thistle, exerts potent anti-inflammatory activities in non-gestational tissues. The aims of this study were to determine the effect of silibinin on pro-inflammatory mediators in (i) human fetal membranes and myometrium treated with bacterial endotoxin lipopolysaccharide (LPS) or the pro-inflammatory cytokine IL-1β, and (ii) in preterm fetal membranes with active infection. The effect of silibinin on infection induced inflammation and brain injury in pregnant mice was also assessed. Fetal membranes and myometrium (tissue explants and primary cells) were treated with 200 μM silibinin in the presence or absence of 10 μg/ml LPS or 1 ng/ml IL-1β. C57BL/6 mice were injected with 70 mg/kg silibinin with or without 50 μg LPS on embryonic day 16. Fetal brains were collected after 6 h. In human fetal membranes, silibinin significantly decreased LPS-stimulated expression of IL-6 and IL-8, COX-2, and prostaglandins PGE2 and PGF2α. In primary amnion and myometrial cells, silibinin also decreased IL-1β-induced MMP-9 expression. Preterm fetal membranes with active infection treated with silibinin showed a decrease in IL-6, IL-8 and MMP-9 expression. Fetal brains from mice treated with silibinin showed a significant decrease in LPS-induced IL-8 and ninjurin, a marker of brain injury. Our study demonstrates that silibinin can reduce infection and inflammation-induced pro-labour mediators in human fetal membranes and myometrium. Excitingly, the in vivo results indicate a protective effect of silibinin on infection-induced brain injury in a mouse model of preterm birth.
    Full-text · Article · Mar 2014 · PLoS ONE
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    • "However, a role for fetal membrane activation in PTD has also been described as clinical and histological chorioamnionitis (inflammation of the amnion and chorion) can lead to preterm premature rupture of membranes (pPROM) (reviewed by Menon & Fortunato (2007) and Gomez-Lopez et al. (2010)). PTD can be artificially induced by treating pregnant mice with LPS (via the i.p., intrauterine, intra-amniotic or vaginal routes), allowing the effect of preterm labour (and potential therapeutic targets) on neonatal morbidity and mortality to be investigated (Elovitz et al. 2003, Pirianov et al. 2009, Burd et al. 2010, Gonzalez et al. 2011). "
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    ABSTRACT: The mechanisms that regulate the induction of term or preterm delivery are not fully understood. Infection is known to play a role in the induction of pro-inflammatory cascades in uteroplacental tissues associated with preterm pathological parturition. Similar, but not identical cascades are evident in term labor. In the current study we used a mouse model to evaluate the role of prokineticins in term and preterm parturition. Prokineticins are multi-functioning secreted proteins that signal through G-protein coupled receptors to induce gene expression, including genes important in inflammatory responses. Expression of prokineticins (Prok1 and Prok2) was quantified in murine uteroplacental tissues by QPCR in the days preceding labor (Day 16 to 19). Prok1 mRNA expression increased significantly on D18 in fetal membranes (compared to D16) but not in uterus or placenta. Intrauterine injection of PROK1 on D17 induced fetal membrane mRNA expression of the pro-inflammatory mediators Il6, Il1B, Tnf, Cxcl2 and Cxcl5 which are not normally upregulated until D19 of pregnancy. However, intrauterine injection of PROK1 did not result in preterm delivery. As expected, injection of LPS induced preterm delivery but this was not associated with changes in expression of Prok1 or its receptor (Prokr1) in fetal membranes. These results suggest that although Prok1 exhibits dynamic mRNA regulation in fetal membranes preceding labor and induces a pro-inflammatory response when injected into the uterus on D17, it is insufficient to induce preterm delivery. Additionally, prokineticin upregulation appears not to be part of the LPS induced inflammatory response in mouse fetal membranes.
    Full-text · Article · Sep 2013 · Reproduction
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