ETS-1 and ETS-2 are upregulated in a transgenic mouse model of pigmented ocular neoplasm

Purpose: Choroidal melanoma is the most common primary malignant ocular tumor in human adults. Relevant mouse models of human uveal melanoma still remain to be developed. We have studied the transgenic mouse strain, Tyrp-1-TAg, to try to gain insight into possible molecular mechanisms common to pigmented ocular neoplasms occurring spontaneously in the eyes of these mice and human choroidal melanoma. The role of two members of the ETS (E26 avian leukemia oncogene) family of transcription factors, ETS-1 and ETS-2, has been investigated in many cancers but has not yet been studied in ocular tumors. Methods: This is the first study describing the production and distribution of ETS-1 and ETS-2 mRNAs and proteins using in situ hybridization and immunohistochemistry in murine ocular tissue sections of normal control eyes and tumoral eyes from mice of the same age. Using semi-quantitative reverse-transcription polymerase chain reaction (RT–PCR) and western blots experiments, we compared changes in ETS-1 and ETS-2 expression, their protein levels, and the regulation of some of their target gene expressions at different stages of the ocular tumoral progression in the transgenic mouse model, Tyrp-1-TAg, with those in normal eyes from control mice of the same age. Results: In normal control adult mouse eyes, ETS-1 was mostly present in the nuclei of all neuroretinal layers whereas ETS-2 was mostly localized in the cytosol of the cell bodies of these layers with a smaller amount present in the nuclei. Both were found in the retinal pigmentary epithelium (RPE). ETS-1 and ETS-2 mRNA and protein levels were much higher in the ocular tissues of Tyrp-1-TAg mice than in control ocular tissues from wild-type mice. This upregulation was correlated with tumor progression. We also demonstrated upregulation of ETS-1 and ETS-2 target expressions in Tyrp-1-TAg mice when comparing with the same target expressions in control mice. Conclusions: Our findings suggest that ETS-1 and ETS-2 are upregulated in ocular tumors derived from the retinal epithelium and may be involved in one or several signaling pathways that activate the expression of a set of genes involved in ocular tumor progression such as those encoding ICAM-1 (intercellular adhesion molecule-1), PAI-1 (Plasminogen activator inhibitor-1), MCP-1 (monocyte chemoattractant protein-1) and p16 (Cyclin dependent kinase inhibitor 2A)

RGD constructs with physical anchor groups as polymer co-electrospinnable cell adhesives

The tissue integration of synthetic polymers can be promoted by displaying RGD peptides at the biointerface with the objective of enhancing colonization of the material by endogenous cells. A firm but flexible attachment of the peptide to the polymer matrix, still allowing interaction with receptors, is therefore of interest. Here, the covalent coupling of flexible physical anchor groups, allowing for temporary immobilization on polymeric surfaces via hydrophobic or dipole–dipole interactions, to a RGD peptide was investigated. For this purpose, a stearate or an oligo(ethylene glycol) (OEG) was attached to GRGDS in 51–69% yield. The obtained RGD linker constructs were characterized by NMR, IR and MALDI-ToF mass spectrometry, revealing that the commercially available OEG and stearate linkers are in fact mixtures of similar compounds. The RGD linker constructs were co-electrospun with poly(p-dioxanone) (PPDO). After electrospinning, nitrogen could be detected on the surface of the PPDO fibers by X-ray photoelectron spectroscopy. The nitrogen content exceeded the calculated value for the homogeneous material mixture suggesting a pronounced presentation of the peptide on the fiber surface. Increasing amounts of RGD linker constructs in the electrospinning solution did not lead to a detection of an increased amount of peptide on the scaffold surface, suggesting inhomogeneous distribution of the peptide on the PPDO fiber surface. Human adipose-derived stem cells cultured on the patches showed similar viability as when cultured on PPDO containing pristine RGD. The fully characterized RGD linker constructs could serve as valuable tools for the further development of tissue-integrating polymeric scaffolds

Fermi liquid theory of electronic topological transitions and screening anomalies in metals

General expressions for the contributions of the Van Hove singularity (VHS)in the electron density of states to the thermodynamic potential $\Omega are obtained in the framework of microscopic Fermi liquid theory. The renormalization of the singularities in$\Omega connected with the Lifshitz electronic topological transition (ETT) is found. Screening anomalies due to virtual transitions between VHS and the Fermi level are considered. It is shown that, in contrast with the one-particle picture of ETT, the singularities in $\Omega turns out to be two-sided for interacting electrons.Comment: 8 pages RevTeX, with minor corrections (Introduction and Conclusions are rewritten, new references are added), to appear in Physical review

The influence of electrospinning parameters on polydioxanone scaffold properties

Conduits currently used to reconstruct the right ventricular outflow tract (RVOT) have no growth potential and require reoperations, resulting in an increased level of morbidity and mortality. This work investigates the effect of electrospinning parameters on the mechanical properties and biocompatibility of bioresorbable tubular scaffolds, as part of a program to develop a tissue-engineered valved tube for RVOT replacement. Electrospinning was used to develop tubular scaffolds of polydioxanone, with the experimental parameters systematically varied. Three electrospinning parameters (volume of liquid, flow rate, and speed of mandrel rotation) were investigated, and their effects on the mechanical properties and cellular response of the scaffolds were analysed using scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, gas chromatography, uniaxial tensile tests, cell viability and cytotoxicity assays. Mechanical properties were compared to those of the native RVOT reported in the literature. Increasing the mandrel rotation speed tended to increase fibre alignment slightly, and led to more profound rises in the stress at failure and Young's modulus. An increase in flow rate also increased the rigidity of the tubes. Cell viability and cytotoxicity assays showed all the tubes produced to have excellent biocompatibility. Through variation of the processing parameters, it is possible to tune mechanical properties of medical-grade polymer tubes over a wide range. By using a mandrel rotation speed of 50 rpm and a flow rate of 20 mL/h or higher we can prepare materials with Young's modulus, strain at failure, and tensile stress close to the native tissue. Electrospinning therefore offers great promise in the development of scaffolds to match the properties of the native RVOT, paving the way to a future bioresorbable device to replace the RVOT in children

Efficient Non-Viral Reprogramming of Myoblasts to Stemness with a Single Small Molecule to Generate Cardiac Progenitor Cells

The current protocols for generation of induced pluripotent stem (iPS) cells involve genome integrating viral vectors which may induce tumorgenesis. The aim of this study was to develop and optimize a non-viral method without genetic manipulation for reprogramming of skeletal myoblasts (SMs) using small molecules

Binding Properties and Stability of the Ras-Association Domain of Rap1-GTP Interacting Adapter Molecule (RIAM)

The Rap1-GTP interacting adapter protein (RIAM) is an important protein in Rap1-mediated integrin activation. By binding to both Rap1 GTPase and talin, RIAM recruits talin to the cell membrane, thus facilitating talin-dependent integrin activation. In this article, we studied the role of the RIAM Ras-association (RA) and pleckstrin-homology (PH) domains in the interaction with Rap1. We found that the RA domain was sufficient for GTP-dependent interaction with Rap1B, and the addition of the PH domain did not change the binding affinity. We also detected GTP-independent interaction of Rap1B with the N-terminus of RIAM. In addition, we found that the PH domain stabilized the RA domain both in vitro and in cells