muramidase and Neuroblastoma

Protein fibrillation is a phenomenon associated with misfolding and the production of highly ordered nanofibrils, which may cause serious degenerative diseases such as Parkinson's disease, Alzheimer's disease, and type 2 diabetes. Upon contact with biological fluids, the nanomaterials are immediately covered by proteins and interact with them. In this study, the effects of Graphene NanoPlateles (Plain-GNPs) and their modified forms with a carboxyl group (GNPs -COOH) and an amine group (GNPs -NH

Topics: Amyloid; Animals; Chickens; Diabetes Mellitus, Type 2; Egg White; Graphite; Muramidase; Neuroblastoma

In amyloid diseases, it is not evident which protein aggregates induce cell death via specific molecular mechanisms and which cause damage because of their mass accumulation and mechanical properties. We showed that equine lysozyme assembles into soluble amyloid oligomers and protofilaments at pH 2.0 and 4.5, 57 degrees C. They bind thioflavin-T and Congo red similar to common amyloid structures, and their morphology was monitored by atomic force microscopy. Molecular volume evaluation from microscopic measurements allowed us to identify distinct types of oligomers, ranging from tetramer to octamer and 20-mer. Monomeric lysozyme and protofilaments are not cytotoxic, whereas the oligomers induce cell death in primary neuronal cells, primary fibroblasts, and the neuroblastoma IMR-32 cell line. Cytotoxicity was accessed by ethidium bromide staining, MTT reduction, and TUNEL assays. Primary cultures were more susceptible to the toxic effect induced by soluble amyloid oligomers than the neuroblastoma cell line. The cytotoxicity correlates with the size of oligomers; the sample incubated at pH 4.5 and containing larger oligomers, including 20-mer, appears to be more cytotoxic than the lysozyme sample kept at pH 2.0, in which only tetramers and octamers were found. Soluble amyloid oligomers may assemble into rings; however, there was no correlation between the quantity of rings in the sample and its toxicity. The cytotoxicity of transient oligomeric species of the ubiquitous protein lysozyme indicates that this is an intrinsic feature of protein amyloid aggregation, and therefore soluble amyloid oligomers can be used as a primary therapeutic target and marker of amyloid disease.

Topics: Amyloid; Amyloidosis; Animals; Cell Death; Cell Line, Tumor; Cells, Cultured; Dimerization; Fibroblasts; Horses; Hydrogen-Ion Concentration; Mice; Mice, Inbred BALB C; Microscopy, Atomic Force; Muramidase; Neuroblastoma; Neurons

One of the hallmarks of neurodegeneration is the accumulation of ubiquitinated proteins in intraneuronal inclusions in the cytosol, endosomes/lysosomes and nuclei of affected cells. The relationship between inclusion production and cell viability is not well understood. On the one hand inclusions may be beneficial and result from an attempt of the cell to isolate a subclass of ubiquitinated proteins that are not effectively degraded. On the other hand, the inclusions may impede normal cell function contributing to cell death. To address this issue we treated mouse neuronal HT4 cells with three toxic agents cadmium, zinc and H2O2, and investigated their effects on glutathione homeostasis, on accumulation of ubiquitinated proteins and on cell viability. The three treatments induce oxidative stress manifested by decreases in glutathione (GSH) and/or increases in protein mixed disulfides (PrSSG). After an overnight recovery period in the absence of treatment, GSH and PrSSG were restored to almost normal levels. However, the levels of ubiquitinated proteins were significantly increased, and cell viability was sharply reduced. These results suggest that the ubiquitin-proteasome pathway is recruited for removal of proteins that are oxidatively modified. However, if the ubiquitinated proteins are not efficiently degraded, they accumulate in the cell and contribute to a decrease in cell viability.

Topics: Animals; Blotting, Western; Cadmium; Cell Survival; Cysteine Endopeptidases; Glutathione; Hydrogen Peroxide; Mice; Multienzyme Complexes; Muramidase; Neuroblastoma; Neurons; Oxidative Stress; Proteasome Endopeptidase Complex; Rabbits; Reticulocytes; Tumor Cells, Cultured; Ubiquitins; Zinc

The presence of lysozyme in the CSF is considered with regard to its value in the early diagnosis of primary or secondary CNS Tumours. Since the appearance of this enzyme in the CSF is secondary to the increase of protein in the fluid, the search for lysozyme in the CSF is of no practical help in the diagnosis of CNS tumours.

Topics: Adolescent; Adult; Aged; Brain Neoplasms; Central Nervous System Diseases; Cerebral Ventricles; Child; Child, Preschool; Craniopharyngioma; Cysts; Female; Glioma; Humans; Hydrocephalus; Infant; Male; Meningioma; Meningitis; Middle Aged; Muramidase; Neoplasm Metastasis; Neurilemmoma; Neuroblastoma; Peripheral Nervous System Neoplasms; Time Factors; Vestibulocochlear Nerve

Topics: Brain Injuries; Brain Neoplasms; Cerebrospinal Fluid; Craniopharyngioma; Glioma; Humans; Meningioma; Muramidase; Neurilemmoma; Neuroblastoma; Vestibulocochlear Nerve