Myometrial‐derived CXCL12 promotes lipopolysaccharide induced preterm labour by regulating macrophage migration,polarization and function in mice

Preterm birth is a major contributor to neonatal mortality and morbidity. Infection results in elevation of inflammation‐related cytokines followed by infiltration of immune cells into gestational tissue. CXCL12 levels are elevated in preterm birth indicating it may have a role in preterm labour (PTL); however, the pathophysiological correlations between CXCL12/CXCR4 signalling and premature labour are poorly understood. In this study, PTL was induced using lipopolysaccharide (LPS) in a murine model. LPS induced CXCL12 RNA and protein levels significantly and specifically in myometrium compared with controls (3‐fold and 3.5‐fold respectively). Highest levels were found just before the start of labour. LPS also enhanced the infiltration of neutrophils, macrophages and T cells, and induced macrophage M1 polarization. In vitro studies showed that condition medium from LPS‐treated primary smooth muscle cells (SMC) induced macrophage migration, M1 polarization and upregulated inflammation‐related cytokines such as interleukin (IL)‐1, IL‐6 and tumor necrosis factor alpha (TNF‐α). AMD3100 treatment in pregnant mice led to a significant decrease in the rate of PTL (70%), prolonged pregnancy duration and suppressed macrophage infiltration into gestation tissue by 2.5‐fold. Further, in‐vitro treatment of SMC by AMD3100 suppressed the macrophage migration, decreased polarization and downregulated IL‐1, IL‐6 and TNF‐α expression. LPS treatment in pregnant mice induced PTL by increasing myometrial CXCL12, which recruits immune cells that in turn produce inflammation‐related cytokines. These effects stimulated by LPS were completely reversed by AMD3100 through blocking of CXCL12/CXCR4 signalling. Thus, the CXCL12/CXCR4 axis presents an excellent target for preventing infection and inflammation‐related PTL.     

HOW COMMON IS HOMOPLOID HYBRID SPECIATION?

Hybridization has long been considered a process that prevents divergence between species. In contrast to this historical view, an increasing number of empirical studies claim to show evidence for hybrid speciation without a ploidy change. However, the importance of hybridization as a route to speciation is poorly understood, and many claims have been made with insufficient evidence that hybridization played a role in the speciation process. We propose criteria to determine the strength of evidence for homoploid hybrid speciation. Based on an evaluation of the literature using this framework, we conclude that although hybridization appears to be common, evidence for an important role of hybridization in homoploid speciation is more circumscribed.     

Toll-like receptor expression in normal ovary and ovarian tumors

Recent studies have implicated inflammation in the initiation and progression of ovarian cancer, though the mechanisms underlying this effect are still not clear. Toll-like receptors (TLRs) allow immune cells to recognize pathogens and to trigger inflammatory responses. Tumor cell expression of TLRs can promote inflammation and cell survival in the tumor microenvironment. Here we sought to characterize the expression of TLRs in normal human ovaries, benign and malignant ovarian tumors from patients, and in established ovarian tumor cell lines. We report that TLR2, TLR3, TLR4, and TLR5 are strongly expressed on the surface epithelium of normal ovaries. In contrast to previous studies of uterus and endocervix, we found no cyclic variation in TLR expression occurred in murine ovaries. TLR2, TLR3, TLR4, and TLR5 are expressed in benign conditions, epithelial tumors, and in ovarian cancer cell lines. Variable expression of TLR6 and TLR8 was seen in benign and malignant epithelium of some patients, while expression of TLR1, TLR7, and TLR9 was weak. Normal and malignant ovarian stroma were negative for TLR expression. Vascular endothelial cells, macrophages, and occasional fibroblasts in tumors were positive. Functional activity for TLRs was demonstrated by stimulation of cell lines with specific ligands and subsequent activation and translocation of NFκB and release of the proinflammatory cytokines interleukin-6 and CCL-2. These studies demonstrate expression of multiple TLRs in the epithelium of normal ovaries and in ovarian tumor cells, and may indicate a mechanism by which epithelial tumors manipulate inflammatory pathways to facilitate tumor progression.     

Abnormal development and increased 3-nitrotyrosine in copper-deficient mouse embryos

Copper-deficient rat embryos are characterized by brain and heart anomalies, low superoxide dismutase activity, and high superoxide anion concentrations. One consequence of increased superoxide anions can be the formation of peroxynitrite, a strong biological oxidant. To investigate developmentally important features of copper deficiency, GD 8.5 mouse embryos from copper-adequate and copper-deficient dams were cultured in media that were adequate or deficient in copper. After 48 h, copper-deficient embryos exhibited brain and heart anomalies, and a high incidence of yolk sac vasculature abnormalities compared to controls. Immunohistochemistry of 4-hydroxynonenal and 8-hydroxy-2'-deoxyguanosine for lipid and DNA damage, respectively, was similar between groups. In contrast, 3-nitrotyrosine, taken as a measure of protein nitration, was markedly higher in the neuroepithelium of the anterior neural tube of copper-deficient embryos than in controls. Repletion of copper-deficient media with copper, or supplementation with copper-zinc superoxide dismutase, Tiron, or glutathione peroxidase did not ameliorate the abnormal development, but did decrease 3-nitrotyrosine in neuroepithelium of copper-deficient embryos. These data support the concept that while copper deficiency compromises oxidant defense and increases protein nitration, additional mechanisms, e.g., altered nitric oxide metabolism may contribute to copper-deficiency-induced teratogenesis.     

Large P body-like RNPs form in C. elegans oocytes in response to arrested ovulation, heat shock, osmotic stress, and anoxia and are regulated by the major sperm protein pathway

As Caenorhabditis elegans hermaphrodites age, sperm become depleted, ovulation arrests, and oocytes accumulate in the gonad arm. Large ribonucleoprotein (RNP) foci form in these arrested oocytes that contain RNA-binding proteins and translationally masked maternal mRNAs. Within 65 min of mating, the RNP foci dissociate and fertilization proceeds. The majority of arrested oocytes with foci result in viable embryos upon fertilization, suggesting that foci are not deleterious to oocyte function. We have determined that foci formation is not strictly a function of aging, and the somatic, ceh-18, branch of the major sperm protein pathway regulates the formation and dissociation of oocyte foci. Our hypothesis for the function of oocyte RNP foci is similar to the RNA-related functions of processing bodies (P bodies) and stress granules; here, we show three orthologs of P body proteins, DCP-2, CAR-1 and CGH-1, and two markers of stress granules, poly (A) binding protein (PABP) and TIA-1, appear to be present in the oocyte RNP foci. Our results are the first in vivo demonstration linking components of P bodies and stress granules in the germ line of a metazoan. Furthermore, our data demonstrate that formation of oocyte RNP foci is inducible in non-arrested oocytes by heat shock, osmotic stress, or anoxia, similar to the induction of stress granules in mammalian cells and P bodies in yeast. These data suggest commonalities between oocytes undergoing delayed fertilization and cells that are stressed environmentally, as to how they modulate mRNAs and regulate translation.     

Prior exposure to indole-3-carbinol decreases the incidence of specific cyclophosphamide-induced developmental defects in mice

BACKGROUND: Indole-3-carbinol (I3C) is a product of the hydrolysis of glucobrassicin that is found in cruciferous vegetables. I3C can intervene in toxic processes that are mediated by oxidative mechanisms because it possesses the chemical and pharmacokinetic properties necessary to provide a free radical trap. Cyclophosphamide (CP) is a bifunctional alkylating agent known to produce DNA damage and to cause developmental toxicity, including malformations, in laboratory animals. METHODS: Pregnant CD-1 mice were given a 100 mg/kg dose of I3C 24 or 48 hr before administration of 20 mg/kg CP on gestation day 10 (GD 10). Controls were given the vehicle (DMSO), I3C, or CP. This regimen was carried out to determine if I3C could protect against the developmental toxicity of alkylating agents, such as CP. Dams were sacrificed on GD 17 and their litters were examined for adverse effects. RESULTS: Treatment with I3C 48 hr before CP administration was associated with decreased fetal limb and tail malformations. Limb malformation incidences were reduced from 42% litters affected in the CP control to 16% in the I3C/CP 48-hr treatment group, and tail malformations were reduced from 45% in the CP control to 16% in the I3C/CP 48-hr treatment group, indicating a protective effect of prior exposure to I3C. I3C given 24 hr before CP had no significant protective effect, while having an apparently adverse consequence with regard to the incidence of talipes. CONCLUSIONS: Exposure of a developing mammal to indole-3-carbinol before exposure to cyclophosphamide during organogenesis can influence the teratogenicity of cyclophosphamide.