Synthesis and release of platelet-activating factor by human vascular endothelial cells treated with tumor necrosis factor or interleukin 1 alpha.

Human endothelial cells synthesize large amounts of platelet-activating factor (PAF) after 30-min treatment with recombinant tumor necrosis factor (TNF). Synthesis of PAF peaks at 4-6 h, whereas in endothelial cells treated with interleukin 1 alpha (IL-1) it peaks at 8-12 h. More than twice as much PAF is synthesized in response to optimal concentrations of TNF than in response to IL-1. However, PAF synthesis is stimulated by lower molar concentrations of IL-1 than TNF. About 30% of PAF produced in response to either TNF or IL-1 is released into the medium, whereas approximately 70% remains cell-associated. Experiments with labeled precursors show that PAF is synthesized de novo in response to TNF. This activity of TNF is inhibited by treating endothelial cells with the inhibitors of protein or RNA synthesis cycloheximide or actinomycin D. This finding may be explained by the observation that TNF induces in endothelial cells an acetyltransferase required for PAF synthesis. The induction of this enzymatic activity precedes the peak of PAF synthesis in TNF-treated cells. After prolonged incubation with either TNF or IL-1, endothelial cells no longer respond to the same monokine, but are still capable of producing PAF when treated with the other monokine. The finding that these monokines do not show reciprocal tachyphylaxis in endothelial cells may be explained by their binding to different receptors. In cells treated simultaneously with different concentrations of TNF and IL-1, PAF synthesis is stimulated in an additive rather than synergistic way. This suggests that PAF is synthesized by the same pathway in response to TNF or IL-1

Salivary extracellular vesicle-associated exRNA as cancer biomarker

Extracellular vesicles (EVs) secreted in biological fluids contain several transcripts of the cell of origin, which may modify the functions and phenotype of proximal and distant cells. Cancer-derived EVs may promote a favorable microenvironment for cancer growth and invasion by acting on stroma and endothelial cells and may favor metastasis formation. The transcripts contained in cancer EVs may be exploited as biomarkers. Protein and extracellular RNA (exRNA) profiling in patient bio-fluids, such as blood and urine, was performed to identify molecular features with potential diagnostic and prognostic values. EVs are concentrated in saliva, and salivary EVs are particularly enriched in exRNAs. Several studies were focused on salivary EVs for the detection of biomarkers either of non-oral or oral cancers. The present paper provides an overview of the available studies on the diagnostic potential of exRNA profiling in salivary EVs

A model of discriminant analysis on the basis of descriptor variables for the ampelography of Vitis sp.

Use of descriptor variables in ampelography is recommended to simplify recording of data and to enable useful comparisons. Parametric assumptions are, however, poorly satisfied especially with regard to statistical interference. In the paper some statistical procedures to improve the discriminant ability of descriptor variables are considered. The use of variances and covariances of variety by year interactions is suggested for the error matrix within a multiple discriminant analysis procedure. The adequacy of this model is verified in a 3-year experiment with Italian wine varieties. The discriminant power, as evaluated on the basis of the estimated distances among varieties, is satisfactory

Role of Lefty in the anti tumor activity of human adult liver stem cells

Recent studies demonstrated that factors derived from embryonic stem cells inhibit the tumorigenicity of a variety of cancer cell lines. Embryonic stem cell-secreted Lefty, an inhibitor of Nodal-signalling pathway, was implicated in reprogramming cancer cells. Whether adult stem cells exhibited similar properties has not been explored. The aim of the present study was to investigate whether the conditioned medium (CM) derived from adult stem cells influence in vitro and in vivo tumor growth by a Nodal-dependent pathway. In particular we compared the anti-tumor effect of CM from human liver stem cells (HLSC) with that of bone marrow-derived mesenchymal stem cells (MSC). We found that HLSC-CM inhibited the in vitro growth and promoted apoptosis in HepG2 cells that expressed a deregulated Nodal pathway. The effect of HLSC-CM was related to the presence of Lefty A in the CM of HLSC. Silencing Lefty A in HLSC or Lefty A blockade with a blocking peptide abrogated the anti-proliferative and pro-apoptotic effect of HLSC-CM. Moreover, the administration of human recombinant Lefty A protein mimicked the effect of HLSC-CM indicating that Nodal pathway is critical for the growth of HepG2. At variance of HLSC, bone marrow-derived MSC did not express and release Lefty A and the MSC-CM did not exhibited an anti-tumor activity in vitro, but rather stimulated proliferation of HepG2. In addition, the intra-tumor administration of HLSC-CM was able to inhibit the in vivo growth of HepG2 hepatoma cells implanted subcutaneously in SCID mice. At variance, HLSC-CM derived from Lefty A silenced HLSC was unable to inhibit tumor growth. In conclusion, the results of present study suggest that Lefty A may account for the tumor suppressive activity of HLSC as a result of an inhibition of the Nodal-signalling pathway by a mechanism similar to that described for embryonic stem cells

A Versatile Model of Microfluidic Perifusion System for the Evaluation of C-Peptide Secretion Profiles: Comparison Between Human Pancreatic Islets and HLSC-Derived Islet-Like Structures

A robust and easy-to-use tool for the ex vivo dynamic evaluation of pancreatic islet (PI) function is essential for further development of novel cell-based therapeutic approaches to treating diabetes. Here, we developed four different glucose perifusion protocols (GPPs) in a microfluidic perifusion system (MPS), based entirely on commercially available components. After validation, the GPPs were used to evaluate C-peptide secretion profiles of PIs derived from different donors (healthy, obese, and type 2 diabetic) and from human liver stem-cell-derived islet-like structures (HLSC-ILS). Using this device, we demonstrated that PIs derived from healthy donors displayed a physiological C-peptide secretion profile as characterized by the response to (a) different glucose concentrations, (b) consecutive pulses of high-glucose concentrations, (c) a glucose threshold ranging from 5–8 mM, and (d) a constant high-glucose perifusion in a biphasic manner. Moreover, we were able to detect a dysregulated secretion profile in PIs derived from both obese and type 2 diabetes mellitus (T2DM) donors. Finally, we also evaluated the kinetic secretion profiles of HLSC-ILS, demonstrating that, nonetheless, with a lower amplitude of secretion compared to PI derived from healthy donors, they were already glucose-responsive on day seven post-differentiation. In conclusion, we have provided evidence that our MPS is a versatile device and may represent a valuable tool to study insulin-producing cells in vitro

Stem cell-derived extracellular vesicles inhibit and revert fibrosis progression in a mouse model of diabetic nephropathy.

Abstract Extracellular vesicles (EVs) that are derived from mesenchymal stromal cells (MSCs) have been shown to reprogram injured cells by activating regenerative processes. We herein investigate the potential therapeutic effect of EVs, shed by human bone marrow MSCs and by human liver stem-like cells (HLSCs), on the progression and reversion of fibrosis in a mouse model of diabetic nephropathy, as induced by streptozotocin. After the development of nephropathy, stem cell-derived EVs were administered weekly to diabetic mice for four weeks. The stem cell-derived EV treatment, but not the fibroblast EV treatment that was used as a control, significantly ameliorated functional parameters, such as albumin/creatinine excretion, plasma creatinine and blood urea nitrogen, which are altered in diabetic mice. Moreover, the renal fibrosis that develops during diabetic nephropathy progression was significantly inhibited in stem cell EV-treated animals. A correlation was found between the down regulation of several pro-fibrotic genes in renal tissues and the anti-fibrotic effect of HLSC and MSC EVs. A comparative analysis of HLSC and MSC EV miRNA content highlighted some common and some specific patterns of miRNAs that target predicted pro-fibrotic genes. In conclusion, stem cell-derived EVs inhibit fibrosis and prevent its progression in a model of diabetes-induced chronic kidney injury