alpha-synuclein and Necrosis

Among therapeutic proposals for amyloid-associated disorders, special attention has been given to the exploitation of nanoparticles (NPs) as promising agents against aggregation.. In this paper, the inhibitory effect of cerium oxide (CeO. It may be concluded that CeO

Topics: alpha-Synuclein; Amyloid; Apoptosis; bcl-2-Associated X Protein; Benzothiazoles; Cell Line, Tumor; Cerium; Congo Red; Humans; Kinetics; Molecular Docking Simulation; Molecular Dynamics Simulation; Nanoparticles; Necrosis; RNA, Messenger; Spectrometry, Fluorescence

Most of the Parkinson's disease (PD) cases are sporadic, although several genes are directly related to PD. Several pathways are central in PD pathogenesis: protein aggregation linked to proteasomal impairments, mitochondrial dysfunctions and impairment in dopamine (DA) release. Here we studied the close crossing of mitochondrial dysfunction and aggregation of α-synuclein (α-syn) and in the extension in the dopaminergic neuronal death. Here, using rat primary cultures of mesencephalic neurons, we induced the mitochondrial impairments using "DA-toxins" (MPP+, 6OHDA, rotenone). We showed that the DA-Toxins induced dopaminergic cell death through different pathways: caspase-dependent cell death for 6OHDA; MPP+ stimulated caspase-independent cell death, and rotenone activated both pathways. In addition, a decrease in energy production and/or a development of oxidative stress were observed and were linked to α-syn aggregation with generation of Lewy body-like inclusions (found inside and outside the dopaminergic neurons). We demonstrated that any of induced mitochondrial disturbances and processes of death led to α-syn protein aggregation and finally to cell death. Our study depicts the cell death mechanisms taking place in in vitro models of Parkinson's disease and how mitochondrial dysfunctions is at the cross road of the pathologies of this disease.

Topics: 1-Methyl-4-phenylpyridinium; alpha-Synuclein; Animals; Apoptosis; Cells, Cultured; Dopaminergic Neurons; Embryo, Mammalian; Energy Metabolism; Female; Humans; Mesencephalon; Mitochondria; Necroptosis; Necrosis; Neurotoxins; Oxidative Stress; Oxidopamine; Parkinson Disease; Primary Cell Culture; Protein Aggregation, Pathological; Rats; Rotenone

Natural food sources constitute a promising source of new compounds with neuroprotective properties, once they have the ability to reach the brain. Our aim was to evaluate the brain accessibility of quercetin, epigallocatechin gallate (EGCG) and cyanidin-3-glucoside (C3G) in relation to their neuroprotective capability. Primary cortical neuron cultures were exposed to oxidative insult in the absence and presence of the selected compounds, and neuroprotection was assessed through evaluation of apoptotic-like and necrotic-like cell death. The brain accessibility of selected compounds was assessed using an optimised human blood-brain barrier model. The blood-brain barrier model was crossed rapidly by EGCG and more slowly by C3G, but not by quercetin. EGCG protected against oxidation-induced neuronal necrotic-like cell death by ~40%, and apoptosis by ~30%. Both quercetin and C3G were less effective, since only the lowest quercetin concentration was protective, and C3G only prevented necrosis by ~37%. Quercetin, EGCG and C3G effectively inhibited α-synuclein fibrillation over the relevant timescale applied here. Overall, EGCG seems to be the most promising neuroprotective compound. Thus, inclusion of this polyphenol in the diet might provide an affordable means to reduce the impact of neurodegenerative diseases.

Topics: alpha-Synuclein; Animals; Anthocyanins; Antioxidants; Apoptosis; Brain; Catechin; Cells, Cultured; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Drug Stability; Endothelial Cells; Flavonoids; Glucosides; Humans; Necrosis; Neurons; Neuroprotective Agents; Oxidative Stress; Protein Multimerization; Quercetin; Rats, Wistar; Recombinant Proteins

Oxidative stress has been proposed to be involved in the pathogenesis of Parkinson's disease (PD). A plausible source of oxidative stress in nigral dopaminergic neurons is the redox reactions that specifically involve dopamine and produce various toxic molecules, i.e., free radicals and quinone species. alpha-Synuclein, a protein found in Lewy bodies characteristic of PD, is also thought to be involved in the pathogenesis of PD and point mutations and multiplications in the gene coding for alpha-synuclein have been found in familial forms of PD.. We used dopaminergic human neuroblastoma BE(2)-M17 cell lines stably transfected with WT or A30P mutant alpha-synuclein to characterize the effect of alpha-synuclein on dopamine toxicity. Cellular toxicity was analyzed by lactate dehydrogenase assay and by fluorescence-activated cell sorter analysis. Increased expression of either wild-type or mutant alpha-synuclein enhances the cellular toxicity induced by the accumulation of intracellular dopamine or DOPA.. Our results suggest that an interplay between dopamine and alpha-synuclein can cause cell death in a neuron-like background. The data presented here are compatible with several models of cytotoxicity, including the formation of alpha-synuclein oligomers and impairment of the lysosomal degradation.

Topics: alpha-Synuclein; Apoptosis; Cell Death; Cell Line, Tumor; Cell Survival; Dihydroxyphenylalanine; Dopamine; Fluorescence; Humans; L-Lactate Dehydrogenase; Mutation, Missense; Necrosis; Neuroblastoma; Neurons; Parkinson Disease; Transfection

The mechanism underlying sodium arsenite (arsenite)-induced neurotoxicity was investigated in rat brain. Arsenite was locally infused in the substantia nigra (SN) of anesthetized rat. Seven days after infusion, lipid peroxidation in the infused SN was elevated and dopamine level in the ipsilateral striatum was reduced in a concentration-dependent manner (0.3-5 nmol). Furthermore, local infusion of arsenite (5 nmol) decreased GSH content and increased expression of heat shock protein 70 and heme oxygenase-1 in the infused SN. Aggregation of alpha-synuclein, a putative pathological protein involved in several CNS neurodegenerative diseases, was elevated in the arsenite-infused SN. From the breakdown pattern of alpha-spectrin, both necrosis and apoptosis were involved in the arsenite-induced neurotoxicity. Pyknotic nuclei, cellular shrinkage and cytoplasmic disintegration, indicating necrosis, and TUNEL-positive cells and DNA ladder, indicating apoptosis was observed in the arsenite-infused SN. Arsenite-induced apoptosis was mediated via two different organelle pathways, mitochondria and endoplasmic reticulum (ER). For mitochondrial activation, cytosolic cytochrome c and caspase-3 levels were elevated in the arsenite-infused SN. In ER pathway, arsenite increased activating transcription factor-4, X-box binding protein 1, C/EBP homologues protein (CHOP) and cytosolic immunoglobulin binding protein levels. Moreover, arsenite reduced procaspase 12 levels, an ER-specific enzyme in the infused SN. Taken together, our study suggests that arsenite is capable of inducing oxidative injury in CNS. In addition to mitochondria, ER stress was involved in the arsenite-induced apoptosis. Arsenite-induced neurotoxicity clinically implies a pathophysiological role of arsenite in CNS neurodegeneration.

Topics: alpha-Synuclein; Animals; Apoptosis; Arsenites; Caspase 3; Corpus Striatum; Cytochromes c; Dopamine; Dose-Response Relationship, Drug; Endoplasmic Reticulum; Glutathione; Heme Oxygenase-1; HSP70 Heat-Shock Proteins; Lipid Peroxidation; Male; Mitochondria; Necrosis; Neurotoxicity Syndromes; Oxidative Stress; Rats; Rats, Sprague-Dawley; Sodium Compounds; Substantia Nigra

Alpha-synuclein (alpha-syn) is an important component of neuronal and glial inclusions in brains of patients with several neurodegenerative disorders. Sporadic inclusion-body myositis (s-IBM) is the most common progressive muscle disease of older patients. Its muscle phenotype shows several similarities with Alzheimer disease brain. A distinct feature of s-IBM pathology is specific vacuolar degeneration of muscle fibers characterized by intracellular amyloid inclusions formed by both amyloid-beta (Abeta) and paired-helical filaments composed of phosphorylated tau. We immunostained alpha-syn in muscle biopsies of s-IBM, disease-control, and normal patients. Approximately 60% of Abeta-positive vacuolated muscle fibers (VMF) contained well-defined inclusions immunoreactive with antibodies against alpha-syn. In those fibers. alpha-syn co-localized with Abeta, both by light microscopy, and ultrastructurally. Paired-helical filaments did not contain alpha-syn immunoreactivity. In all muscle biopsies, alpha-syn was strongly immunoreactive at the postsynaptic region of the neuromuscular junctions. alpha-syn immunoreactivity also occurred diffusely in regenerating and necrotic muscle fibers. In cultured human muscle fibers, alpha-syn and its mRNA were expressed by immunocytochemistry, immunoblots, and Northern blots. Our study provides the first demonstration that alpha-syn participates in normal and pathologic processes of human muscle. Therefore. its function is not exclusive to the brain and neurodegenerative diseases.

Topics: alpha-Synuclein; Cells, Cultured; Fluorescent Antibody Technique; Humans; Inclusion Bodies; Microscopy, Immunoelectron; Muscle Fibers, Skeletal; Muscle, Skeletal; Myositis, Inclusion Body; Necrosis; Nerve Tissue Proteins; Neuromuscular Junction; Regeneration; Synucleins