Search results for "Epithelial Cells"
showing 10 items of 400 documents
Polymeric drug delivery micelle-like nanocarriers for pulmonary administration of beclomethasone dipropionate
2017
In this paper, the potential of novel polymeric micelles as drug delivery systems for Beclomethasone Dipropionate (BDP) administration into the lung is investigated. These nanostructures are obtained starting from α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA), which was subsequently functionalized with O-(2-aminoethyl)-Oâ-methylpolyethylenglycole (PEG2000), ethylenediamine (EDA) and lipoic acid (LA), obtaining PHEA-PEG2000-EDA-LA graft copolymer. Empty and drug-loaded micelles possess adequate chemical-physical characteristics for pulmonary administration such as spherical shape, slightly positive surface charge and mean size of about 200 nm. Besides, BDP-loaded micelles, obtained …
Sustained activation of mTOR pathway in embryonic neural stem cells leads to development of tuberous sclerosis complex-associated lesions
2011
SummaryTuberous Sclerosis Complex (TSC) is a multisystem genetic disorder characterized by hamartomatous neurological lesions that exhibit abnormal cell proliferation and differentiation. Hyperactivation of mTOR pathway by mutations in either the Tsc1 or Tsc2 gene underlies TSC pathogenesis, but involvement of specific neural cell populations in the formation of TSC-associated neurological lesions remains unclear. We deleted Tsc1 in Emx1-expressing embryonic telencephalic neural stem cells (NSCs) and found that mutant mice faithfully recapitulated TSC neuropathological lesions, such as cortical lamination defects and subependymal nodules (SENs). These alterations were caused by enhanced gen…
Nickel induces intracellular calcium mobilization and pathophysiological responses in human cultured airway epithelial cells.
2009
Abstract Environmental exposure to nickel is associated to respiratory disorders and potential toxicity in the lung but molecular mechanisms remain incompletely explored. The extracellular Ca 2+ -sensing receptor (CaSR) is widely distributed and may be activated by divalent cations. In this study, we investigated the presence of CaSR in human cultured airway epithelial cells and its activation by nickel. Nickel transiently increased intracellular calcium (−log EC 50 = 4.67 ± 0.06) in A549 and human bronchial epithelial cells as measured by epifluorescence microscopy. Nickel (20 μM)-induced calcium responses were reduced after thapsigargin or ryanodine exposure but not by Ca 2+ -free medium…
Thymoma and paraneoplastic myasthenia gravis
2010
Paraneoplastic autoimmune diseases associate occasionally with small cell lung cancers and gynecologic tumors. However, myasthenia gravis (MG) occurs in at least 30% of all patients with thymomas (usually present at MG diagnosis). These epithelial neoplasms almost always have numerous admixed maturing polyclonal T cells (thymocytes). This thymopoiesis-and export of mature CD4(+)T cells-particularly associates with MG, though there are rare/puzzling exceptions in apparently pure epithelial WHO type A thymomas. Other features potentially leading to inefficient self-tolerance induction include defective epithelial expression of the autoimmune regulator (AIRE) gene and/or of major histocompatib…
Side-specific effects by cadmium exposure: Apical and basolateral treatment in a coculture model of the blood–air barrier
2010
Cadmium (Cd{sup 2+}) is a widespread environmental pollutant, which is associated with a wide variety of cytotoxic and metabolic effects. Recent studies showed that intoxication with the heavy metal most importantly targets the integrity of the epithelial barrier. In our study, the lung epithelial cell line, NCI H441, was cultured with the endothelial cell line, ISO-HAS-1, as a bilayer on a 24-well HTS-Transwell (registered) filter plate. This coculture model was exposed to various concentrations of CdCl{sub 2}. The transepithelial electrical resistance decreased on the apical side only after treatment with high Cd{sup 2+} concentrations after 48 h. By contrast, a breakdown of TER to less t…
The effect of ions at the surface of calcium oxalate monohydrate crystals on cell-crystal interactions
2003
Magnesium is an abundant ion in biologic systems, including renal tubular fluid; however, the precise role of magnesium during the interaction of calcium oxalate crystals with cells has not been previously defined. In addition, the respective roles of calcium and hydrogen ions during the cell-crystal bonding interaction remain poorly defined. Here we report an atomic level three-dimensional study of a single crystal of calcium oxalate monohydrate (COM; whewellite) which was bathed in a solution of magnesium hexahydrate for 1 year. Magnesium was not incorporated into the structure of whewellite to any significant degree. Instead, COM accepted magnesium primarily as an adsorbate in a binding …
Cadmium regulation of apoptotic and stress response genes in tumoral and immortalized epithelial cells of the human breast
2008
Cadmium (Cd) is a widely-disseminated metal which can be imported and accumulated in living cells thereby drastically interfering with their biological mechanisms. Increasing interest has been recently focused on the elucidation of the cellular and molecular aspects of Cd-dependent regulation of gene expression and signal transduction pathways in different model system. Concerning breast cancer, very limited studies have been produced so far on the role played by Cd on estrogen receptor-negative human breast cancer cells, that are expected to be insensitive to the already-proven metallo-estrogenic effect exerted by Cd on the estrogen receptor-positive cell counterparts. Here, we have examin…
Interactions of silica nanoparticles with lung epithelial cells and the association to flotillins
2012
Amorphous silica nanoparticles (aSNPs) gain increasing popularity for industrial and therapeutic claims. The lung with its surface area of 100-140 m(2) displays an ideal target for therapeutic approaches, but it represents also a serious area of attack for harmful nanomaterials. The exact nature of the cytotoxic effects of NPs is still unknown. Furthermore, cellular pathways and the destiny of internalized NPs are still poorly understood. Therefore, we examined the cytotoxicity (MTS, LDH) and inflammatory responses (IL-8) for different-sized aSNPs (30, 70, 300 nm) on our lung epithelial cells line NCI H441 and endothelial cell line ISO-HAS-1. Additionally, colocalization studies have been c…
Desmosomes: interconnected calcium-dependent structures of remarkable stability with significant integral membrane protein turnover
2002
Desmosomes are prominent cell adhesion structures that are major stabilizing elements, together with the attached cytoskeletal intermediate filament network, of the cytokeratin type in epithelial tissues. To examine desmosome dynamics in tightly coupled cells and in situations of decreased adhesion, fluorescent desmosomal cadherin desmocollin 2a (Dsc2a) chimeras were stably expressed in human hepatocellular carcinoma-derived PLC cells (clone PDc-13) and in Madin-Darby canine kidney cells (clone MDc-2) for the continuous monitoring of desmosomes in living cells. The hybrid polypeptides integrated specifically and without disturbance into normal-appearing desmosomes that occurred in associati…
Role of tir and intimin in the virulence of rabbit enteropathogenic Escherichia coli serotype O103:H2.
2000
ABSTRACT Attaching and effacing (A/E) rabbit enteropathogenic Escherichia coli (REPEC) strains belonging to serogroup O103 are an important cause of diarrhea in weaned rabbits. Like human EPEC strains, they possess the locus of enterocyte effacement clustering the genes involved in the formation of the A/E lesions. In addition, pathogenic REPEC O103 strains produce an Esp-dependent but Eae (intimin)-independent alteration of the host cell cytoskeleton characterized by the formation of focal adhesion complexes and the reorganization of the actin cytoskeleton into bundles of stress fibers. To investigate the role of intimin and its translocated coreceptor (Tir) in the pathogenicity of REPEC, …