endometrium such as specific cytokines equilibrium, growth factors and angiogenic factors but also some specific immunological target cells.Despite research and technique progresses, despite a lot of publications defining profiles -normal or pathological-at the genomic and proteomic level, the molecular fingerprint of the receptive endometrium remains unknown (Berlanga et al., 2011;Rashid et al., 2011;Singh et al., 2011).The progression of implantation and then pregnancy requires immunological tolerance which allows conceptus survival.It has been proposed that uterine natural killer cells (uNK) could exert, directly or indirectly, either positive or negative control over these early steps (Dosiou and Giudice, 2005).These cells secrete an array of cytokines important for adequate local immune regulation, angiogenesis, placental development, and establishment of pregnancy.Successful subsequent placentation and remodeling of the uterine vasculature is a fundamental step for a healthy pregnancy that requires also a highly orchestrated reciprocal signaling process.Deficiencies in this process are implicated in a number of dangerous pregnancy complications with excess (percreta/accreta placentation) or defective implantation (preeclampsia, intra uterine growth restriction).Implantation failure, recurrent miscarriage and preeclampsia have several recognized causes in common, but in most cases, the precise etiology remains obscure.The most limiting and difficult issue to evaluate during the implantation process is the dialogue at the materno-fetal interface.Embryo is able to cross-talk with the endometrium through different molecules, cytokines and hormones.It is able to actively participate to its own implantation and to influence endometrial gene expression (Kashiwagi et al., 2007).Inversely, endometrium is competent to differently answer to the implanting embryo, to favor or reject implantation (Bauersachs et al., 2009).Moreover, the cytokine network acting in the female reproductive tract around implantation integrates environmental information to program the embryo and fine-tune the maternal immune response and endometrial remodeling to determine implantation success (Robertson et al., 2011).All these interactions are not accessible to the researcher for obvious ethical reasons that let understand why implantation remains the black box of reproduction, even in 2012.Among the factors produced by the embryo, its specific signal chorionic gonadotropin hormone (hCG) and its hyperglycosylated form H-hCG are another example of target molecules at this crossroads of immune tolerance, angiogenesis, and invasive process at the maternal-fetal interface.This chapter will overview the recent literature and personal data concerning impact of gametes, endometrium and embryo during implantation process.
In addition to lethal minute colony mutations which correspond to loss of mitochondrial DNA, acriflavin induces in Chlamydomonas reinhardtii a low percentage of cells that grow in the light but do not divide under heterotrophic conditions. Two such obligate photoautotrophic mutants were shown to lack the cyanide-sensitive cytochrome pathway of the respiration and to have a reduced cytochrome c oxidase activity. In crosses to wild type, the mutations are transmitted almost exclusively from the mating type minus parent. A same pattern of inheritance is seen for the mitochondrial DNA in crosses between the two interfertile species C. reinhardtii and Chlamydomonas smithii. Both mutants have a deletion in the region of the mitochondrial DNA containing the apocytochrome b gene and possibly the unidentified URFx gene.
To evaluate the presence and potential involvement of members of the plasminogen/plasminogen activator (Plg/PA) system in the exudative form of age-related macular degeneration (AMD).The expression of PA members mRNA was evaluated in human and experimental choroidal neovascularization (CNV) by RT-PCR. The presence and activity of PA was studied by immunofluorescence and in situ zymography. The influence of endogenous plasminogen (Plg), urokinase (uPA), tissue type plasminogen activator (tPA), and uPA receptor (uPAR) was explored in single-gene-deficient mice in a model of laser-induced CNV.Members of the Plg/PA system were present both in human and murine CNV. The absence of Plg, uPA, or tPA significantly decreased the development of experimental CNV compared with wild-type or uPAR-deficient mice. This effect could be attributable, partly to a modulation of matrix metalloproteinase activity, but also to an accumulation of fibrinogen-fibrin in the laser-induced wounds.Together with previous work done by the authors, this study indicates that choroidal neovascularization is extremely sensitive to the modulation of Plg/PA system activity. This may provide a new strategy for the treatment of exudative AMD.
Abstract Membrane‐type 4 matrix metalloprotease (MT4‐MMP) expression in breast adenocarcinoma stimulates tumor growth and metastatic spreading to the lung. However, whether these pro‐tumorigenic and pro‐metastatic effects of MT4‐MMP are related to a proteolytic action is not yet known. Through site directed mutagenesis MT4‐MMP has been inactivated in cancer cells through Glutamic acid 249 substitution by Alanine in the active site. Active MT4‐MMP triggered an angiogenic switch at day 7 after tumor implantation and drastically accelerated subcutaneous tumor growth as well as lung colonization in recombination activating gene‐1‐deficient mice. All these effects were abrogated upon MT4‐MMP inactivation. In sharp contrast to most MMPs being primarily of stromal origin, we provide evidence that tumor‐derived MT4‐MMP, but not host‐derived MT4‐MMP contributes to angiogenesis. A genetic approach using MT4‐MMP‐deficient mice revealed that the status of MT4‐MMP produced by host cells did not affect the angiogenic response. Despite of this tumor intrinsic feature, to exert its tumor promoting effect, MT4‐MMP requires a permissive microenvironment. Indeed, tumor‐derived MT4‐MMP failed to circumvent the lack of an host angio‐promoting factor such as plasminogen activator inhibitor‐1. Overall, our study demonstrates the key contribution of MT4‐MMP catalytic activity in the tumor compartment, at the interface with host cells. It identifies MT4‐MMP as a key intrinsic tumor cell determinant that contributes to the elaboration of a permissive microenvironment for metastatic dissemination.
Purpose.: To evaluate the antilymphangiogenic potential of multi-target tyrosine kinase inhibitor sunitinib in corneal neovascularization (NV). Methods.: Inflammatory corneal NV was induced by thermal cauterization applied in the central cornea of mice, to which sunitinib malate was daily administered by gavage or not. At days 6, 11, or 17 post cauterization, lymphatic and blood vessels, as well as inflammatory cells were immunostained and quantified in whole-mounted corneas. RT-PCRs were performed to evidence VEGF–A, VEGF-C, VEGF-D, placental growth factor (PlGF), and soluble vascular endothelial growth factor receptor (VEGFR)-1 and -2 (sVEGFR-1, sVEGFR-2) expressions. Macrophages were isolated from mice peritoneal cavity following thioglycollate injection to produce conditioned medium. The effects of sunitinib were evaluated in vitro in the aortic and lymphatic ring assays in the presence or not of macrophage conditioned medium. Results.: Sunitinib treatment drastically reduced pathologic corneal lymphangiogenesis and angiogenesis. Reduced F4/80+ cell infiltration was evidenced in sunitinib-treated mice and was associated to decreased VEGF-A (by 50%, P < 0.01) and VEGF-C (by 35%, P < 0.01) expressions, while VEGF-D and sVEGFR-2 expressions were not affected. In vitro, sunitinib dose-dependently inhibited aortic ring outgrowth, but failed to affect lymphangiogenesis in the lymphatic ring assay. However, macrophage conditioned medium-enhanced angiogenesis and lymphangiogenesis were both strongly counteracted by sunitinib treatment. Mechanistically, sunitinib blocked VEGFR-2 phosphorylation induced by VEGF-A released by macrophages. Conclusions.: Sunitinib exerts antihemangiogenic and antilymphangiogenic effects in vivo by reducing F4/80+ cell recruitment and interacting with their released factors.
The cyclic growth, differentiation, and cell death of endometrium represents the most dynamic example of steroid-driven tissue turnover in human adults. Key effectors in these processes—matrix metalloproteinases (MMPs) and their specific inhibitors (TIMPs)—are regulated by ovarian steroids and, locally, by cytokines. We used reverse transcription-polymerase chain reaction to evaluate the expression of both transcriptionally regulated molecules such as estrogen receptor-α, progesterone receptor, and prolactin and a large array of MMPs and TIMPs (MMP-1, -2, -3, -7, -8, -9, -11, -12, -19, -26, MT1-MMP, MT2-MMP, MT3-MMP, TIMP-1, -2, -3). Altogether, three distinct patterns of MMP and two patterns of TIMP expression were detected in cycling endometrium: 1) MMPs restricted to the menstrual period (MMPs-1, -3, -8, -9, -12); 2) MMPs and TIMPs expressed throughout the cycle (MMP-2, MT1-MMP, MT2-MMP, MMP-19, TIMP-1, and TIMP-2); 3) MMPs predominantly expressed during the proliferative phase (MMP-7, MMP-11, MMP-26, and MT3-MMP); and 4) TIMP-3, which, contrary to the other TIMPs, shows significant modulations, with maximum expression during the late secretory and menstrual phases. These specific patterns of MMP expression associated with each phase of the cycle may point to specific roles in the processes of menstruation, housekeeping activities, angiogenesis, tissue growth, and extracellular matrix remodeling.
Membrane-type 1 matrix metalloproteinase (MT1-MMP) and vascular endothelial growth factor (VEGF) are two key molecules involved in pericellular proteolysis and cell proliferation during tumor growth and an-giogenesis. Our previous data showed that MT1-MMP overexpression in human breast carcinoma MCF7 cells induced an up-regulation of VEGF expression. This effect was associated in vivo with accelerated tumor growth and angiogenesis. We now provide evidence that MT1-MMP overexpression specifically affected VEGF-A production and failed to influence that of other VEGF family members (VEGF, B, C, D, or P1GF) or their receptors. The up-regulation of VEGF-A by MT1-MMP was related to an increased transcriptional activation rather than to a modification of mRNA stability. It was blocked by synthetic MMP inhibitors, TIMP2, but not TIMP-1 and abolished by a partial deletion of the catalytic domain or the cytoplasmic tail of MT1-MMP. Analysis of the signal transduction mechanisms demonstrated that MT1-MMP acts through a signaling pathway involving Src tyrosine kinases. Thus, our results provide new insight into the mechanisms of action of MT1MMP during angiogenesis and suggest that the full enzymatic activity of MT1-MMP is required for a specific up-regulation of VEGF-A through an activation of Src tyrosine kinase pathways. The abbreviations used are: VEGF, vascular endothelial growth factor; P1GF, placental-like growth factor;
