Search results for " Glycoproteins"
showing 10 items of 329 documents
The plasma membrane channel ORAI1 mediates detrimental calcium influx caused by endogenous oxidative stress.
2013
The mouse hippocampal cell line HT22 is an excellent model for studying the consequences of endogenous oxidative stress. Addition of extracellular glutamate depletes the cells of glutathione (GSH) by blocking the glutamate-cystine antiporter system x(c)(-). GSH is the main antioxidant in neurons and its depletion induces a well-defined program of cell death called oxytosis, which is probably synonymous with the iron-dependent form of non-apoptotic cell death termed ferroptosis. Oxytosis is characterized by an increase of reactive oxygen species and a strong calcium influx preceding cell death. We found a significant reduction in store-operated calcium entry (SOCE) in glutamate-resistant HT2…
Dendritic cells as mediators of tumor-induced tolerance in metastatic melanoma.
1997
Escape from immune surveillance is critical for tumor progression in metastatic melanoma. We assessed the function of melanoma-derived dendritic cells (DCs) in patients presenting simultaneously with responding (rM) or progressing (pM) melanoma metastases. These rare coincidences allowed us to compare syngeneically the function of tumor DCs. CD83+ DCs were purified freshly from large responding (rDCs) or progressing (pDCs) metastases following chemo-immunotherapy. rDCs were 5 times more potent inducers of allogeneic T-cell proliferation than the pDCs that were used as control. Phenotypic analysis showed a marked depression of CD86 expression on pDCs. Culture supernatants from pM showed prod…
CD83+ human dendritic cells transfected with tumor peptide cDNA by electroporation induce specific T-cell responses: A potential tool for gene immuno…
2000
Dendritic cells (DC) are the most potent immunostimulatory cells, with the capacity to induce primary T-cell responses. Functional autologous DC can be generated from fetal calf serum-free peripheral blood mononuclear cells in the presence of interleukin-4 and granulocyte-macrophage colony-stimulating factor and are stimulated with a defined cytokine cocktail for terminal maturation. We were able to establish a nonviral transfection protocol for these DC by electroporation. Using enhanced green fluorescent protein as a reporter gene, we achieved transfection efficiencies of up to 10%. FACScan analyses revealed a stable phenotype, and the expression of major histocompatibility complex class …
Synaptophysin expressed in the bronchopulmonary tract: neuroendocrine cells, neuroepithelial bodies, and neuroendocrine neoplasms.
1987
Synaptophysin is an integral membrane glycoprotein with an Mr of 38,000 that occurs in the small, clear vesicles present in neuronal cells and tumors as well as in pancreatic islet cells and various neuroendocrine (NE) carcinomas. We found that synaptophysin is also expressed in normal NE cells of the lungs of newborn rabbits and mice as well as of human fetuses. In bronchial ganglion cells and in nerves, synaptophysin is coexpressed with neurofilament proteins (NFPs), whereas in solitary NE cells and in at least some of the neuroepithelial bodies (NEBs) of the bronchial mucosal lining, synaptophysin coexists with cytokeratins. We also studied a series of NE neoplasms of the lung covering t…
Expression and regulation by interferon-γ of the membrane-bound complement regulators CD46 (MCP), CD55 (DAF) and CD59 in gastrointestinal tumours
1999
The membrane-bound complement inhibitors CD46 (membrane cofactor protein), CD55 (decay-accelerating factor) and CD59 (protectin) protect tumour cells against lysis by activated complement. In this study, a total of 14 (3 gastric, 3 colonic and 8 pancreatic) gastrointestinal tumour cell lines were examined for the expression of CD46, CD55 and CD59 with respect to the regulatory efficacy of interferon-gamma (IFN-gamma). The effects of IFN-gamma on mRNA and protein expression levels of CD46, CD55 and CD59 were evaluated by Northern blot hybridisation, RT-PCR, flow cytometry and immunostaining. In unstimulated cell lines, CD46 and CD59 transcripts were expressed at comparable levels, whereas th…
Dendritic cell-tumor cell hybrids and immunotherapy: what's next?
2011
Dendritic cells (DC) are professional antigen-presenting cells currently being used as a cellular adjuvant in cancer immunotherapy strategies. Unfortunately, DC-based vaccines have not demonstrated spectacular clinical results. DC loading with tumor antigens and DC differentiation and activation still require optimization. An alternative technique for providing antigens to DC consists of the direct fusion of dendritic cells with tumor cells. These resulting hybrid cells may express both major histocompatibility complex (MHC) class I and II molecules associated with tumor antigens and the appropriate co-stimulatory molecules required for T-cell activation. Initially tested in animal models, …
Study of surface carbohydrates on isolated Golgi subfractions by fluorescent-lectin binding and flow cytometry
1995
The Golgi complex is a functionally heterogeneous subcellular structure that plays a key role in the synthesis, maturation, and sorting of newly synthesized glycoproteins. Fluorescent lectins have been used extensively to analyze surface glycoproteins by flow cytometry in whole cells and more recently in isolated subcellular organelles, such as mitochondria and chloroplasts. We report here the use of several fluorescein-isothiocyanate-conjugated lectins to detect and quantify specific surface sugars by flow cytometry on isolated elements from purified cis and trans-Golgi fractions from rat liver. Our results show that this approach may be useful to study Golgi composition and function, sinc…
Protein targeting to the plasma membrane of adult skeletal muscle fiber: an organized mosaic of functional domains.
2001
The plasma membrane of differentiated skeletal muscle fibers comprises the sarcolemma, the transverse (T) tubule network, and the neuromuscular and muscle-tendon junctions. We analyzed the organization of these domains in relation to defined surface markers, beta-dystroglycan, dystrophin, and caveolin-3. These markers were shown to exhibit highly organized arrays along the length of the fiber. Caveolin-3 and beta-dystroglycan/dystrophin showed distinct, but to some extent overlapping, labeling patterns and both markers left transverse tubule openings clear. This labeling pattern revealed microdomains over the entire plasma membrane with the exception of the neuromuscular and muscle-tendon j…
An unconventional role for miRNA: let-7 activates Toll-like receptor 7 and causes neurodegeneration
2011
Activation of innate immune receptors by host-derived factors exacerbates CNS damage, but the identity of these factors remains elusive. We uncovered an unconventional role for the microRNA let-7, a highly abundant regulator of gene expression in the CNS, in which extracellular let-7 activates the RNA-sensing Toll-like receptor (TLR) 7 and induces neurodegeneration through neuronal TLR7. Cerebrospinal fluid (CSF) from individuals with Alzheimer’s disease contains increased amounts of let-7b, and extracellular introduction of let-7b into the CSF of wild-type mice by intrathecal injection resulted in neurodegeneration. Mice lacking TLR7 were resistant to this neurodegenerative effect, but thi…
Growth control in mammalian cells by cell-cell contacts.
1990
Growth of normal diploid mammalian cells in vitro is strongly regulated by the actual cell density. Cell-cell contacts via specific plasma membrane glycoproteins whose glycan moieties interact with specific receptors has been found to be a main growth regulatory principle. Malignant growth is suggested to result from impaired function of these receptors.