No abstract

Highlights d Reprogramming of patient somatic cells to induced hTSCs with OSKM d Conversion of naive and extended hPSCs to hTSCs d Comparison of models of the human trophoblast lineage d h(i/c)TSCs are akin to day 8 trophoblasts of the human embryo

The involvement of diesel exhaust particles (DEPs) in respiratory diseases was evaluated by studying their effects on two in vitro models of human airway epithelial cells. The cytotoxicity of DEPs, their phagocytosis, and the resulting immune response were investigated in a human bronchial epithelial cell line (16HBE14o−) as well as in human nasal epithelial cells in primary culture. DEP exposure induced a time- and dose-dependent membrane damage. Transmission electron microscopy showed that DEPs underwent endocytosis by epithelial cells and translocated through the epithelial cell sheet. Flow cytometric measurements allowed establishment of the time and dose dependency of this phagocytosis and its nonspecificity with different particles (DEPs, carbon black, and latex particles). DEPs also induced a time-dependent increase in interleukin-8, granulocyte-macrophage colony-stimulating factor, and interleukin-1β release. This inflammatory response occurred later than phagocytosis, and its extent seems to depend on the content of adsorbed organic compounds because carbon black had no effect on cytokine release. Furthermore, exhaust gas posttreatments, which diminished the adsorbed organic compounds, reduced the DEP-induced increase in granulocyte-macrophage colony-stimulating factor release. These results suggest that DEPs could 1) be phagocytosed by airway epithelial cells and 2) induce a specific inflammatory response.

Nitric oxide (NO), a free radical that is negatively inotropic in the heart and skeletal muscle, is produced in large amounts during sepsis by an NO synthase inducible (iNOS) by LPS and/or cytokines. The aim of this study was to examine iNOS induction in the rat diaphragm after Escherichia Coli LPS inoculation (1.6 mg/kg i.p.), and its involvement in diaphragmatic contractile dysfunction. Inducible NOS protein and activity could be detected in the diaphragm as early as 6 h after LPS inoculation. 6 and 12 h after LPS, iNOS was expressed in inflammatory cells infiltrating the perivascular spaces of the diaphragm, whereas 12 and 24 h after LPS it was expressed in skeletal muscle fibers. Inducible NOS was also expressed in the left ventricular myocardium, whereas no expression was observed in the abdominal, intercostal, and peripheral skeletal muscles. Diaphragmatic force was significantly decreased 12 and 24 h after LPS. This decrease was prevented by inhibition of iNOS induction by dexamethasone or by inhibition of iNOS activity by N G -methyl-L -arginine. We conclude that iNOS was induced in the diaphragm after E. Coli LPS inoculation in rats, being involved in the decreased muscular force. ( J. Clin. Invest. 1996. 98:1550-1559.)

A critical step in the establishment of human pregnancy is the invasion of the uterus wall by extravillous cytotrophoblasts (EVCTs) during the first trimester. It is well established that human chorionic gonadotropin hormone (hCG) is secreted by the endocrine syncytiotrophoblast (ST) into the maternal compartment. We recently reported that invasive EVCTs also produce hCG, suggesting an autocrine role in the modulation of trophoblast invasion. Here we analyzed the role of hCG secreted in vitro by primary cultures of invasive EVCT and noninvasive ST. We first demonstrated that LH/CG receptor was present in EVCTs in situ and in vitro as well as in an EVCT cell line (HIPEC65). We next showed that hCG secreted by EVCTs stimulated progesterone secretion by MA10 cells in a concentration-dependent manner. Incubation of HIPEC65 with EVCT supernatants induced a 10-fold increase in cell invasion, whereas ST supernatants had no effect. This stimulating effect was strongly decreased when hCG was depleted from EVCT supernatants containing a large amount of the hyperglycosylated form of hCG, which is almost undetectable in ST supernatants. Finally, we investigated the regulation of hCG expression by peroxisome proliferator-activated receptor (PPAR)-gamma, a nuclear receptor shown to inhibit trophoblast invasion. Activation of PPARgamma decreased alpha- and beta-subunit transcript levels and total hCG secretion in primary EVCTs. Our results offer the first evidence that hCG secreted by the invasive trophoblast, likely the hyperglycosylated form of hCG, but not by the syncytiotrophoblast, promotes trophoblast invasion and may be a PPARgamma target gene in trophoblast invasion process.

We report the measurement of thermal conductance of silicon nanowires at low temperature. It is demonstrated that the roughness at the nanometer scale plays a crucial role for the phonon transport in low-dimensional samples. To this end, using e-beam lithography, nanowires of size 200 nm by 100 nm and 10 microm long have been nanofabricated. Their thermal properties have been measured using the 3 omega method between 0.3 and 6 K. The change in the temperature behavior of the thermal conductance (quadratic temperature dependence of K(T)) is a signature of an intermediate regime lying between the classical Casimir regime and the quantum regime. The Casimir-Ziman model is used to show that this specific behavior originates in mesoscopic samples where the dominant phonon wavelength becomes commensurate to the characteristic length of the roughness of the nanowire surfaces.

No abstract

Plasma concentrations of biologically active vitamin D (1,25-(OH)2D) are tightly controlled via feedback regulation of renal 1␣-hydroxylase (CYP27B1; positive) and 24-hydroxylase (CYP24A1; catabolic) enzymes. In pregnancy, this regulation is uncoupled, and 1,25-(OH) 2 D levels are significantly elevated, suggesting a role in pregnancy progression. Epigenetic regulation of CYP27B1 and CYP24A1 has previously been described in cell and animal models, and despite emerging evidence for a critical role of epigenetics in placentation generally, little is known about the regulation of enzymes modulating vitamin D homeostasis at the fetomaternal interface. In this study, we investigated the methylation status of genes regulating vitamin D bioavailability and activity in the placenta. No methylation of the VDR (vitamin D receptor) and CYP27B1 genes was found in any placental tissues. In contrast, the CYP24A1 gene is methylated in human placenta, purified cytotrophoblasts, and primary and cultured chorionic villus sampling tissue. No methylation was detected in any somatic human tissue tested. Methylation was also evident in marmoset and mouse placental tissue. All three genes were hypermethylated in choriocarcinoma cell lines, highlighting the role of vitamin D deregulation in this cancer. Gene expression analysis confirmed a reduced capacity for CYP24A1 induction with promoter methylation in primary cells and in vitro reporter analysis demonstrated that promoter methylation directly down-regulates basal promoter activity and abolishes vitamin D-mediated feedback activation. This study strongly suggests that epigenetic decoupling of vitamin D feedback catabolism plays an important role in maximizing active vitamin D bioavailability at the fetomaternal interface.In eutherian mammals, proper fetal growth and development are dependent on the formation and function of the placenta. In combination with the maternal decidua, cells of the placenta (primarily trophoblasts) regulate the exchange of nutrients, growth factors, oxygen, and waste between maternal and fetal circulations. The placenta also protects the developing pregnancy from the maternal immune system (1).Although mammalian placentas share a basic common function in modulating exchange at the fetomaternal interface, it is clear that the human placenta is unique in structure and function (2). Animal models may therefore be of limited value in fully dissecting processes underlying certain aspects of human pathologies, such as pre-eclampsia and gestational trophoblastic disease (3). An examination of human placentation is therefore critical in understanding its unique function and potential role in disease.The biologically active form of vitamin D (1,25-(OH) 2 D) 4 is a potent secosteroid hormone. Its wide ranging actions include regulating calcium and phosphorus homeostasis, immune system modulation, cellular differentiation, and apoptosis (4 -6). It also has potent antiproliferative effects (7-9). Vitamin D deficiency has been linked to several adverse pregnancy outco...