[Protein Homeostasis Dysregulation in Pathogenesis of Neurodegenerative Diseases].

The formation and accumulation of unfolded, misfolded, or damaged cellular proteins leads to development of endoplasmic reticulum stress (ER stress). A series of protective reactions is initiated in response to ER stress. These reactions are aimed at restoring the balance between protein synthesis and degradation, which is key to maintaining protein homeostasis (proteostasis). The main protective mechanisms are the attenuation of protein synthesis, increase of chaperone levels, and activation of protein degradation systems. Insufficiency or malfunction of these mechanisms induce apoptosis. Proteostasis dysregulation accompanied by protein aggregation and subsequent cell death in specific regions of the nervous system is a common pathogenetic hallmark of most neurodegenerative diseases. We discuss targeted regulation of the ER stress signaling pathways as a potential therapeutic strategy that can slow or even halt the disease progression.

[Comparative Analysis of MPTP Neurotoxicity in Mice with a Constitutive Knockout of the α-Synuclein Gene].

Aggregated forms of α-synuclein are core components of pathohistological inclusions known as Lewy bodies in substantia nigra (SN) neurons of patients with Parkinson's disease (PD). The role of α-synuclein in selective loss of SN dopaminergic neurons (DNs) in PD is studied in mice knocked out in the α-synuclein gene. The new mouse strain delta flox KO with a constitutive knockout of the α-synuclein gene models the end point of in vivo deletion of the α-synuclein gene in mice with a conditional knockout and has no foreign sequence in the modified genomic locus, thus differing from all other α-synuclein knockout mouse strains. The effect of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which is used to model PD, was compared between delta flox KO mice and mice of the well-known α-synuclein knockout strain AbKO. Subchronic MPTP administration, which models early PD, was found to reduce the dopamine content and to change the ratio of dopamine metabolites in the striatum to the same levels in delta flox KO, АbKO, and wild-type mice. Overt locomotor defects were not observed after MPTP treatment, but gait testing in a CatWalk XT (Noldus) system revealed identical gait deviations in mice of the two strains and control wild-type mice. Based on the findings, a similar mechanism of neurotoxic damage to DNs was assumed for delta flox KO and AbKO mice.

Increased Expression of the Multimerin-1 Gene in α-Synuclein Knokout Mice.

Multimerin-1 (Mmrn-1) is a soluble protein, also known as elastin microfibril interfacer 4 (EMILIN-4), found in platelets and in the endothelium of blood vessels. Its function and role in pathology are still not fully understood. Genetic modifications in alpha-synuclein gene (Snca) locus that mapped 160 Kb apart from Mmrn-1 in mouse genome, could weigh with regulatory elements of Mmrn-1 gene. We have studied the Mmrn-1 expression in brain cortex of three mouse lines with Snca knock-out: B6(Cg)-Sncatm1.2Vlb/J, B6;129-Sncatm1Sud/J, and B6;129X1-Sncatm1Rosl/J. The 35-fold increase for Mmrn-1 mRNA level have been found in B6;129X1-Sncatm1Rosl/J mice that carry in their genome foreign sequences including bacterial gene neo and a strong promoter of a mouse phosphoglycerate kinase (Pgk1) oriented towards Mmrn-1 gene. This effect on regulatory elements of Mmrn-1 gene as a result of modifications in Snca locus should be taken into consideration when using B6;129X1-Sncatm1Rosl/J line, that is widely applied for study of neurodegeneration mechanisms.

[The association of gamma-synuclein autoantibodies with the polymorphism in exon 4 of the coding gene]. / Sviaz' nalichiia autoantitel k gamma-sinukleinu s polimorfizmom v 4-m ékzone kodiruiushchego gena.

AIM: To analyze the polymorphism in exon 4 of the gamma-synuclein gene (SNCG) in patients with autoantibodies against the gamma-synuclein protein. MATERIAL AND METHODS: To identify autoantibodies against gamma-synuclein, the serum from patients with chronic cerebral ischemia and cervical osteochondrosis was used. All patients were women of the Slavic ethnic group, mean age 61±5 years. The isolated genomic DNA was used to determine the point mutation in exon 4 by the restriction endonuclease HphI and subsequent sequencing of the resulting fragments to confirm the results. RESULTS AND CONCLUSION: Antibodies against gamma-synuclein were identified in 2 patients with chronic cerebral ischemia and 3 with cervical osteochondrosis. All five patients had a T to A substitution at position 371, which was detected by the restriction endonuclease HphI resulting in a hydrolysis of the amplicon and the formation of two fragments. The subsequent sequencing of exon 4 of the SNCG revealed no other mutations and confirmed the T to A substitution. This single nucleotide polymorphism results in the amino acid substitution of glutamic acid to valine at position 110 (out of 127), changing its physicochemical properties and the ability to form aggregates as well as post-translational modifications. The obtained results provide grounds for further association studies of SNCG polymorphism in patients with various diseases of the nervous system.

[The FUS protein: Physiological functions and a role in amyotrophic lateral sclerosis].

Certain forms of amyotrophic lateral sclerosis (ALS) are associated with an altered compartmentalization of FUS and its aggregation in the cytoplasm of motoneurons. FUS is a DNA/RNA-binding protein that is involved in DNA repair and the regulation of transcription, splicing, RNA transport, and local translation. Two theories have been proposed to explain the mechanism of the pathophysiological process in ALS. The theories attribute degeneration of motor neurons to either loss or gain of FUS function. The review describes the main physiological functions of FUS and considers evidence for each of the theories of ALS pathogenesis.

[Dimebon delays the onset of symptoms of FUS-proteinopathy in transgenic mice]. / Otsrochennyi debiut simptomaticheskoi stadii FUS-proteinopatii u transgennykh myshei pod deistviem dimebona.

AIM: To evaluate an effect of dimebon on the onset of symptomatic stage in FUS.1-513 transgenic mice - a new genetic model of neurodegeneration, and to study the dynamics of disease progression in the terminal stage. MATERIAL AND METHODS: The study was carried out on males of line FUS1-513 with the contribution of genes from CD1 strains. Mice of the experimental group (n=28) received dimebon with water in the concentration of 70 mcg/ml starting from the 35th day of life. The control group (n=25) did not receive the drug. Age, body mass of animals at the start of symptomatic stage and duration of symptomatic stage were assessed. RESULTS: Application of dimebon can delay the onset of the manifestation of clinical symptoms of the neurodegenerative process in the experimental group (127.6±4.6 days) compared to the control group (110.6±4.2 days). The body mass was similar in both groups. CONCLUSION: Dimebon leads to an increase in the duration of presymptomatic stage and delays the manifestation of clinical symptoms. The changes in the dynamics of the pathological process in the symptomatic stage are not detected.

Detection of autoantibodies to potentially amyloidogenic protein, gamma-synuclein, in the serum of patients with amyotrophic lateral sclerosis and cerebral circulatory disorders.

In this study, we analyzed serum for the presence of antibodies to gamma-synuclein in patients with amyotrophic lateral sclerosis (ALS) compared to the control group of patients with other neurological diseases and healthy control donors. As a result, antibodies against gamma-synuclein are not an ALS-specific feature and have been identified in patients with ALS as well as in the control group patients. Patients with the impaired cerebral circulation showed increased incidence of autoantibodies to gamma-synuclein, yet the difference lacks statistical representativeness due to limited sample size.

Psychotropic Activity of New Fluorinated Derivatives of Tetrahydrocarbasoles.

Psychotropic properties of CA-7043× and CA-7050×, new fluorinated derivatives of tetrahydrocarbasoles, were examined on outbred CD1 mice and transgenic 5×FAD mice with Alzheimer disease. Both agents exerted cognitive-stimulating and anxiolytic effects in a dose of 5 mg/kg. In the new cage test, they retarded extinction of orientation and exploratory behavior. CA-7043× produced an anxiolytic effect on CD1 mice assessed in the open-field test and exerted cognitive-stimulating action in the new location test. In the same tests, CA-7050× demonstrated the cognitive-stimulating and anxiolytic effects on transgenic 5×FAD mice.

[Molecular aspects of the pathogenesis and current approaches to pharmacological correction of Alzheimer's disease].

This review addresses the current hypotheses of the pathogenesis of Alzheimer's disease (AD) and methods of its pharmacological corrections. The following topics are reviewed: a role of ß-amyloid in the pathogenesis of AD, a role of tau-protein in the pathogenesis of AD, main hypotheses of the pathogenesis, the relationship between ß-amyloid and tau-protein, the dysfunction of synapses in AD, a neuroimmune hypothesis, treatment approaches.

[A mice model of amyotrophic lateral sclerosis expressing mutant human FUS protein].

UNLABELLED: BACKGROUND AND ОBJECTIVE: Loss of conformation and function of sufficient number of proteins with high aggregation capacity plays an important role in the pathogenesis of many neurodegenerative disorders (NDD). Due to a recent discovery of new array of proteins with the capacity to form aggregates of nonamyloid type, new NDD models as well as a new level of understanding in vivo models which are already exist is needed. DNA/RN A binding proteins - FUS and TDP-43 play a crucial role in the pathogenesis of some forms of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. The objective of the study was to develop a new ALS transgenic model. MATERIAL AND METHODS: In cell culture experiments, we studied mutant FUS proteins capable to form intracellular deposits morphologically similar to those observed in the autopsy material of ALS patients. RESULTS AND CONCLUSION: We created a transgenic mice line, in which a pathogenic form of human FUS protein was expressed in the nervous system. That led to the aggregation of FUS protein in spinal cord and motor neurons with the following degeneration and development of a phenotype, similar to the human ALS disease phenotype, in young grown-up animals. This neurodegenerative phenotype corresponds to a great number of clinical manifestations of human ALS and is an adequate transgenic model of the disease.