[Expression of Mas1 receptor in human placenta and its effect on the function of trophoblast cells in pre-eclampsia patients].

Objective: To investigate the expression change of the Mas1 receptor in the placenta of healthy pregnant women during different gestation periods, analyze the expression level of the Mas1 receptor in the placenta of pre-eclampsia (PE) patients, and its biological function in trophoblast cells. Methods: Placental villous tissues were collected from normal pregnant women in early, mid and late pregnancy. Human trophoblast stem cells were isolated and cultured from early pregnancy villous tissues. The expression of the Mas1 receptor was detected by fluorescence immunoassay and real-time fluorescence quantitative PCR. In a case-control study, patients with full-term PE were selected as the case group and healthy women with full-term pregnancy were selected as the control group. Placental villus tissues were collected from both groups. Immunofluorescence chemistry and immunoprotein blotting were used to study the changes in Mas1 receptor expression in PE. Mas1 receptor agonists and blockers induced HTR8/Svneo cells and BeWo cells, and the effects of the Mas1 receptor on the proliferation and migration of trophoblast cells were detected by the CCK8 proliferation test and scratch test. Results: Eight cases were included in early pregnancy, seven cases in mid-pregnancy and six cases in late pregnancy. Mas1 receptors in normal placental villi tissue were mainly expressed in human trophoblast stem cell membranes and cytoplasm, and the expression of Mas1 receptor mRNA in villi tissue was significantly higher in late pregnancy than in mid-pregnancy. There were 24 cases included in the case group and 12 cases in the control group. Mas1 receptor expression in placental villi was significantly lower in the case group compared to the control group; Activation/inhibition of the Mas1 receptor had no significant effect on the proliferation of HTR8/Svneo cells and BeWo cells. Activated Mas1 receptor had no significant effect on the migration ability of HTR8/Svneo cells. Conclusion: Mas1 receptors are expressed in placental villous tissue and their expression varies with gestation. Mas1 receptor expression is reduced in PE patients, but it does not affect the value-added or migratory function of trophoblast cells.

Investigation of microbiologically influenced corrosion inhibition of 304 stainless steel by D-cysteine in the presence of Pseudomonas aeruginosa.

The influence of D-cysteine (D-cys) on the microbiologically influenced corrosion (MIC) of 304 stainless steel caused by Pseudomonas aeruginosa was investigated in this work. Immersion tests in the sterile and P. aeruginosa-inoculated culture media with different D-cys concentrations were carried out. The results showed that the addition of D-cys inhibited the formation of P. aeruginosa biofilms on stainless steel surfaces. D-cys itself did not affect the corrosion of stainless steel but could decrease the corrosion rate of MIC of stainless steel caused by P. aeruginosa. X-ray photoelectron spectroscopy (XPS) analysis and scanning electrochemical microscopy (SECM) analysis indicated that the biofilm inhibition effect of D-cys greatly reduced the destructive effect of the adhered P. aeruginosa cells on the passive film of the stainless steel, thus inhibiting the MIC of the stainless steel.

Homology-directed dna repair, mitomycin-c resistance, and chromosome stability is restored with correction of a Brca1 mutation.

Chromosomal breaks occur spontaneously as a result of normal DNA metabolism and after exposure to DNA-damaging agents. A major pathway involved in chromosomal double-strand break repair is homologous recombination. In this pathway, a DNA sequence with similarity to a damaged chromosome directs the repair of the damage. The protein products of the hereditary breast cancer susceptibility genes, BRCA1 and BRCA2, interact with the Rad51 protein, a central component of homologous repair pathways. We have recently shown that this interaction is significant by demonstrating that Brca1- and BRCA2-deficient cells are defective in homology-directed chromosomal break repair. We confirm that Brca1-deficient embryonic stem (ES) cells are defective in gene targeting and homology-directed repair of an I-Sce I-induced chromosome break. The phenotypic paradigm that defines homology-directed repair mutants is extended to these Brca1-deficient cells by the demonstration of 100-fold sensitivity to the interstrand cross-linking agent mitomycin-C and spontaneous chromosome instability. Interestingly, although chromosome aberrations were evident, aneuploidy was not observed. Repair phenotypes are partially restored by expression of a Brca1 transgene, whereas correction of one mutated Brca1 allele through gene targeting fully restores mitomycin-C resistance and chromosome stability. We conclude that the inability to properly repair strand breaks by homology-directed repair gives rise to defects in chromosome maintenance that promote genetic instability and, it is likely, tumorigenesis.

Interleukin-1 beta regulates human cytotrophoblast metalloproteinase activity and invasion in vitro.

During early human pregnancy, fetal cytotrophoblasts rapidly invade the uterus. This process has many similarities to tumor invasion, except that the extent and the timing of cytotrophoblast invasion are carefully regulated. Therefore, this system is particularly useful for studying mechanisms that regulate invasive processes. Previously, we showed that production and activation of the 92-kDa type IV collagenase (matrix metalloproteinase(MMP)-9) is necessary for cytotrophoblast invasion in vitro. In other systems, interleukin (IL)-1 beta is an important regulator of matrix-degrading metalloproteinases. Therefore, we investigated trophoblast production of IL-1 beta and its receptors, as well as the effects of this cytokine on cytotrophoblast metalloproteinase activity and invasion. The results showed that release of IL-1 beta parallels the invasive potential of the cytotrophoblasts; the highest levels are produced by first trimester cells and the lowest levels by term cells. Immunoprecipitation showed that cytotrophoblasts express the 80-kDa type I IL-1 receptor, suggesting that autocrine effects are possible. IL-1 beta stimulated trophoblast MMP-9 secretion (by a mechanism that required nascent mRNA and protein synthesis) as well as metalloproteinase activity and invasion of Matrigel. Increasing (by lipopolysaccharide treatment) or decreasing (by glucocorticoid treatment) IL-1 beta production had parallel effects on MMP-9 secretion, metalloproteinase activity, and invasion. Because IL-1 beta and corticosteroids are present in high concentrations at the maternal-fetal interface, normal trophoblast invasion may be regulated, in part, by their opposing actions. In contrast, stimulation of cytotrophoblast IL-1 beta secretion by lipopolysaccharide may play a role in the sequela of infected fetal membranes.

An inhibitor of the matrix metalloproteinase synthesized by rabbit corneal epithelium.

Normal and abnormal processes of cellular invasion often are initiated by degradation of basement membranes. The process of corneal ulceration might operate via similar mechanisms; degradation of the corneal stroma is not seen until after the basement membrane underlying the corneal epithelium in the preulcerative lesion is lost. Recent data implicate a member of the matrix metalloproteinase (MMP) family of enzymes, 92 kD gelatinase/type IV collagenase (MMP-9) in both cellular invasion processes and degradation of epithelial basement membrane before corneal ulceration. This suggests that use of nontoxic substances that block activity of MMP-9 might be useful in preventing or inhibiting pathologic invasion processes in vivo. An agent that fits these criteria is N-[D,L-2-isobutyl-3(N'-hydroxycarbonylamido)-propanoyl]-O- methyl-L-tyrosine methylamide, which previously has been characterized as an inhibitor of tumor cell collagenases. In this study, the authors show that the inhibitor can efficiently block activity of MMP-9 purified from cultures of rabbit corneal epithelial cells. Results suggest that the recently reported efficacy of a closely related inhibitor in blocking progression of alkali burns to ulceration might be attributable to its action against MMP-9.

Adhesive and degradative properties of human placental cytotrophoblast cells in vitro.

Human fetal development depends on the embryo rapidly gaining access to the maternal circulation. The trophoblast cells that form the fetal portion of the human placenta have solved this problem by transiently exhibiting certain tumor-like properties. Thus, during early pregnancy fetal cytotrophoblast cells invade the uterus and its arterial network. This process peaks during the twelfth week of pregnancy and declines rapidly thereafter, suggesting that the highly specialized, invasive behavior of the cytotrophoblast cells is closely regulated. Since little is known about the actual mechanisms involved, we developed an isolation procedure for cytotrophoblasts from placentas of different gestational ages to study their adhesive and invasive properties in vitro. Cytotrophoblasts isolated from first, second, and third trimester human placentas were plated on the basement membrane-like extracellular matrix produced by the PF HR9 teratocarcinoma cell line. Cells from all trimesters expressed the calcium-dependent cell adhesion molecule cell-CAM 120/80 (E-cadherin) which, in the placenta, is specific for cytotrophoblasts. However, only the first trimester cytotrophoblast cells degraded the matrices on which they were cultured, leaving large gaps in the basement membrane substrates and releasing low molecular mass 3H-labeled matrix components into the medium. No similar degradative activity was observed when second or third trimester cytotrophoblast cells, first trimester human placental fibroblasts, or the human choriocarcinoma cell lines BeWo and JAR were cultured on radiolabeled matrices. To begin to understand the biochemical basis of this degradative behavior, the substrate gel technique was used to analyze the cell-associated and secreted proteinase activities expressed by early, mid, and late gestation cytotrophoblasts. Several gelatin-degrading proteinases were uniquely expressed by early gestation, invasive cytotrophoblasts, and all these activities could be abolished by inhibitors of metalloproteinases. By early second trimester, the time when cytotrophoblast invasion rapidly diminishes in vivo, the proteinase pattern of the cytotrophoblasts was identical to that of term, noninvasive cells. These results are the first evidence suggesting that specialized, temporally regulated metalloproteinases are involved in trophoblast invasion of the uterus. Since the cytotrophoblasts from first trimester and later gestation placentas maintain for several days the temporally regulated degradative behavior displayed in vivo, the short-term cytotrophoblast outgrowth culture system described here should be useful in studying some of the early events in human placen

The physico-chemical properties of cancer-suppressive factor.

Biological fluids of mammalia possess a cancer-suppressive activity. CSF has been isolated from ascitic fluid (Ehrlich ascites carcinoma) in this laboratory. Chemically, it is a peptide complexing with lipids, and inhibits the cancer cells in vitro, but has a little effect on normal bone marrow cells. This paper reports the molecular homogeneity, amino acid composition, approximate molecular weight and terminal structures of the peptide.