[Changes in the mitochondrial subproteome of mouse brain Rpn13-binding proteins induced by the neurotoxin MPTP and the neuroprotector isatin]. / Izmenenie mitokhondrial'nogo subproteoma Rpn13-sviazyvaiushchikh belkov mozga myshi pod deistviem neirotoksina MFTP i neiroprotektora izatina.

Mitochondrial dysfunction and ubiquitin-proteasome system (UPS) failure contribute significantly to the development of Parkinson's disease (PD). The proteasome subunit Rpn13 located on the regulatory (19S) subparticle play an important role in the delivery of proteins, subjected to degradation, to the proteolytic (20S) part of proteasome. We have previously found several brain mitochondrial proteins specifically bound to Rpn13 (Buneeva et al. (2020) Biochemistry (Moscow), Supplement Series B: Biomedical Chemistry, 14, 297-305). In this study we have investigated the effect of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and the neuroprotector isatin on the mitochondrial subproteome of Rpn13-binding proteins of the mouse brain. Administration of MPTP (30 mg/kg) to animals caused movement disorders typical of PD, while pretreatment with isatin (100 mg/kg, 30 min before MPTP) reduced their severity. At the same time, the injection of MPTP, isatin, or their combination (isatin + MPTP) had a significant impact on the total number and the composition of Rpn13-binding proteins. The injection of MPTP decreased the total number of Rpn13-binding proteins in comparison with control, and the injection of isatin prior to MPTP or without MPTP caused an essential increase in the number of Rpn13-binding proteins, mainly of the functional group of proteins participating in the protein metabolism regulation, gene expression, and differentiation. Selected biosensor validation confirmed the interaction of Rpn13 subunit of proteasome with some proteins (glyceraldehyde-3-phosphate dehydrogenase, pyruvate kinase, histones H2A and H2B) revealed while proteomic profiling. The results obtained testify that under the conditions of experimental MPTP-induced parkinsonism the neuroprotective effect of isatin may be aimed at the interaction of mitochondria with the components of UPS.

The Effect of Neurotoxin MPTP and Neuroprotector Isatin on the Profile of Ubiquitinated Brain Mitochondrial Proteins.

Mitochondria are a crucial target for the actions of neurotoxins, causing symptoms of Parkinson's disease in various experimental animal models, and also neuroprotectors. There is evidence that mitochondrial dysfunction induced by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) influences functioning of the ubiquitin-proteasomal system (UPS) responsible for selective proteolytic degradation of proteins from various intracellular compartments (including mitochondria) and neuroprotective effects of certain anti-Parkisonian agents (monoamine oxidase inhibitors) may be associated with their effects on the UPS. In this study, we have investigated the effect of the neurotoxin MPTP and neuroprotector isatin, and their combination on the profile of ubiquitinated brain mitochondrial proteins. The development of movement disorders induced by MPTP administration caused dramatic changes in the profile of ubiquitinated proteins associated with mitochondria. Pretreatment with the neuroprotector isatin decreased manifestations of MPTP-induced Parkinsonism, and had a significant impact on the profile of ubiquitinated mitochondrial proteins (including oxidative modified proteins). Administration of isatin alone to intact mice also influenced the profile of ubiquitinated mitochondrial proteins, and increased the proportion of oxidized proteins carrying the ubiquitination signature. These alterations in the ubiquitination of mitochondrial proteins observed within 2 h after administration of MPTP and isatin obviously reflect immediate short-term biological responses to these treatments.

Isatin, an endogenous nonpeptide biofactor: A review of its molecular targets, mechanisms of actions, and their biomedical implications.

Isatin (indole-2,3-dione) is an oxidized indole. It is widely distributed in mammalian tissues and body fluids, where isatin concentrations vary significantly from <0.1 to > 10 µM. Isatin output is increased under conditions of stress. Exogenously administered isatin is characterized by low toxicity, mutagenicity, and genotoxicity in vivo. Cytotoxic effects of isatin on various cell cultures are usually observed at concentrations exceeding 100 µM. Binding of [3 H]isatin to rat brain sections is consistent with its physiological concentrations. Proteomic analysis of mouse and rat brain isatin-binding proteins revealed about 90 individual proteins, which demonstrated significant interspecies differences (rat versus mouse). Certain evidence exist that redox state(s) and possibly other types of posttranslational modifications regulate affinity of target proteins to isatin. Recent data suggest that interacting with numerous intracellular isatin binding proteins, isatin can act as a regulator of complex protein networks in norm and pathology. Physiological concentrations of isatin in vitro inhibit monoamine oxidase B and natriuretic peptide receptor guanylate cyclase, higher (neuroprotective) concentrations (50-400 µM) cause apoptosis of various (including malignant tumor) cell lines and influence expression of certain apoptosis-related genes. Being administered in vivo, isatin exhibits various behavioral effects; it attenuates manifestations of MPTP-induced parkinsonism and tumor growth in experimental animal models. © 2017 BioFactors, 44(2):95-108, 2018.

[The effect of neurotoxin MPTP administration to mice on the proteomic profile of brain isatin-binding proteins]. / Vliianie neirotoksina MFTP na proteomnyi profil' izatin-sviazyvaiushchikh belkov mozga myshei.

Isatin (indole-2,3-dione) is an endogenous indole found in the mammalian brain, peripheral organs and body fluids. It acts as a neuroprotector, which decreases manifestation of locomotor impairments in animal models of Parkinson's disease. A wide range of biological activity of isatin is associated with interaction of this regulator with numerous isatin-binding proteins. The aim of this study was to investigate the profile of brain isatin-binding proteins in mice with MPTP-induced Parkinsonism (90 min and seven days after administration of this neurotoxin). A single dose administration of MPTP (30 mg/kg, ip.) was accompanied by locomotor impairments in the open field test 90 min after administration; seven days after MPTP administration locomotor activity of mice significantly improved but did not reach the control level. Five independent experiments on proteomic profiling of isatin-binding proteins resulted in confident identification of 96±12 proteins. Development of MPTP-induced locomotor impairments was accompanied by a significant decrease in the number of isatin-binding proteins (63±6; n=5; p<0.01). Seven days after MPTP administration the total number of identified proteins increased and reached the control level (132±34; n=4). The profiles of isatin-binding proteins were rather specific for each group of mice: in the control group these proteins (which were not found in both groups of MPTP-treated mice) represented more than 70% of total proteins. In the case of MPTP treated mice this parameter was 60% (90 min after MPTP administration) and >82% (seven days after MPTP administration). The major changes were found in the groups of isatin-binding proteins involved into cytoskeleton formation and exocytosis, regulation of gene expression, cell division and differentiation and also proteins involved in signal transduction.