Magnetic resonance imaging-guided focused ultrasound thalamotomy launch with remote telemedicine international proctorship

Background

COVID-19 limitations have hindered the implementation of new technologies by preventing proctors from coming to the site. We share our first experience of magnetic resonance imaging (MRI)-guided focused ultrasound (MRgFUS) treatment with an international remote online proctorship, and develop and evaluate the methodology of remote MRgFUS proctorship.

Methods

This single-center, nonrandomized controlled prospective study included 94 patients: 27 with essential tremor (ET) and 67 with tremor-dominant Parkinson's disease (PD). The coming of proctors was impossible, so we arranged for the remote participation of proctors from the United Kingdom, Spain, and Israel. A total of 38 patients (40.4%) received telemedicine-proctored treatment (proctor group) and 56 received their treatment independently (solo group). We used the Clinical Rating Scale for Tremor (CRST) for ET patients and the Unified Parkinson's Disease Rating Scale (UPDRS) Part III for PD patients.

Results

In patients with ET, success rates were 81.8% (proctor group) and 100% (solo group) (p = 0.22). CRST reduction on the treated side was 71.43% [65.83%; 80.56%] (proctor group) versus 60.87% [53.99; 79.58] (solo group) (p = 0.19). None of the patients showed worsening of tremors within 1 year. In patients with PD, the success rates were 92.6% (proctor group) and 100% (solo group) (p = 0.08). The UPDRS Part III improvement was 30.1% (proctor group) versus 39.9% (solo group) (p = 0.003). The 1-year recurrence rate was 40% (proctor group) and 17.5% (solo group) (p = 0.04). No complications were observed at 6 months.

Conclusions

We developed a feasible and safe methodology for telemedicine remote online-proctored MRgFUS treatment. No significant difference was observed between the solo and developed remote proctor protocols in terms of complication rate, effect, and long-term results; however, UPDRS Part III improvement was better in the PD solo group. This study demonstrated that the MRgFUS international proctorship can be performed successfully remotely.

Substitution of Met-38 to Ile in γ-synuclein found in two patients with amyotrophic lateral sclerosis induces aggregation into amyloid

α-, β-, and γ-Synuclein are intrinsically disordered proteins implicated in physiological processes in the nervous system of vertebrates. α-synuclein (αSyn) is the amyloidogenic protein associated with Parkinson's disease and certain other neurodegenerative disorders. Intensive research has focused on the mechanisms that cause αSyn to form amyloid structures, identifying its NAC region as being necessary and sufficient for amyloid assembly. Recent work has shown that a 7-residue sequence (P1) is necessary for αSyn amyloid formation. Although γ-synuclein (γSyn) is 55% identical in sequence to αSyn and its pathological deposits are also observed in association with neurodegenerative conditions, γSyn is resilient to amyloid formation in vitro. Here, we report a rare single nucleotide polymorphism (SNP) in the SNCG gene encoding γSyn, found in two patients with amyotrophic lateral sclerosis (ALS). The SNP results in the substitution of Met38 with Ile in the P1 region of the protein. These individuals also had a second, common and nonpathological, SNP in SNCG resulting in the substitution of Glu110 with Val. In vitro studies demonstrate that the Ile38 variant accelerates amyloid fibril assembly. Contrastingly, Val110 retards fibril assembly and mitigates the effect of Ile38. Substitution of residue 38 with Leu had little effect, while Val retards, and Ala increases the rate of amyloid formation. Ile38 γSyn also results in the formation of γSyn-containing inclusions in cells. The results show how a single point substitution can enhance amyloid formation of γSyn and highlight the P1 region in driving amyloid formation in another synuclein family member.

Current progress and challenges in the development of brain tissue models: How to grow up the changeable brain in vitro?

In vitro modeling of brain tissue is a promising but not yet resolved problem in modern neurobiology and neuropharmacology. Complexity of the brain structure and diversity of cell-to-cell communication in (patho)physiological conditions make this task almost unachievable. However, establishment of novel in vitro brain models would ultimately lead to better understanding of development-associated or experience-driven brain plasticity, designing efficient approaches to restore aberrant brain functioning. The main goal of this review is to summarize the available data on methodological approaches that are currently in use, and to identify the most prospective trends in development of neurovascular unit, blood-brain barrier, blood-cerebrospinal fluid barrier, and neurogenic niche in vitro models. The manuscript focuses on the regulation of adult neurogenesis, cerebral microcirculation and fluids dynamics that should be reproduced in the in vitro 4D models to mimic brain development and its alterations in brain pathology. We discuss approaches that are critical for studying brain plasticity, deciphering the individual person-specific trajectory of brain development and aging, and testing new drug candidates in the in vitro models.

[Hypothalamic hamartoma dissection using focused ultrasound under MRI control. The first successful experience in Russia]

Treatment of motor disorders by MRI-guided focused ultrasound is an alternative to neuro- and radiosurgery such as stereotactic radiofrequency ablation and thalamotomy with a gamma knife. However, safety, efficacy and feasibility of this technology for intracranial neoplasms are still unclear. The authors report successful hypothalamic hamartoma dissection by MRI-guided focused ultrasound in a 32-year-old woman with drug-resistant gelastic epilepsy and violent laughter and crying attacks. Magnetic resonance imaging revealed type II hypothalamic hamartoma. The last one was detached from surrounding brain tissue by MRI-guided focused ultrasound without side effects. Symptoms regressed immediately after surgery. No laughter and crying attacks were observed throughout 6-month follow-up.

Neurophysiological hallmarks of Huntington's disease progression: an EEG and fMRI connectivity study

Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) can provide corroborative data on neurophysiological alterations in Huntington's disease (HD). However, the alterations in EEG and fMRI resting-state functional connectivity (rsFC), as well as their interrelations, at different stages of HD remain insufficiently investigated. This study aimed to identify neurophysiological alterations in individuals with preclinical HD (preHD) and early manifest HD (EMHD) by analyzing EEG and fMRI rsFC and examining their interrelationships. We found significant differences in EEG power between preHD individuals and healthy controls (HC), with a decrease in power in a specific frequency range at the theta-alpha border and slow alpha activity. In EMHD patients, in addition to the decrease in power in the 7-9 Hz range, a reduction in power within the classic alpha band compared to HC was observed. The fMRI analysis revealed disrupted functional connectivity in various brain networks, particularly within frontal lobe, putamen-cortical, and cortico-cerebellar networks, in individuals with the HD mutation compared to HC. The analysis of the relationship between EEG and fMRI rsFC revealed an association between decreased alpha power, observed in individuals with EMHD, and increased connectivity in large-scale brain networks. These networks include putamen-cortical, DMN-related and cortico-hippocampal circuits. Overall, the findings suggest that EEG and fMRI provide valuable information for monitoring pathological processes during the development of HD. A decrease in inhibitory control within the putamen-cortical, DMN-related and cortico-hippocampal circuits, accompanied by a reduction in alpha and theta-alpha border oscillatory activity, could potentially contribute to cognitive decline in HD.

Anomia: Deciphering Functional Neuroanatomy in Primary Progressive Aphasia Variants

Naming decline is one of the most common symptoms of primary progressive aphasia (PPA). Most studies on anomia in PPA are performed without taking into account PPA variants, especially for action naming. Only limited data are available for the neuroanatomical basis of anomia considering differences in the pathogenesis of PPAs. The aim of our study is to investigate the associations between anomia severity for both noun and verb naming and gray matter (GM) atrophy, as well as accompanying functional connectivity (FC) changes in three PPA variants. A total of 17 patients with non-fluent (nfvPPA), 11 with semantic (svPPA), and 9 with logopenic (lvPPA) PPA variants were included in the study and underwent cognitive/naming assessments and brain MRIs. Voxel-based morphometry was performed to evaluate GM volume. A resting-state functional MRI was applied to investigate FC changes in the identified GM areas. The study shows that different brain regions are involved in naming decline in each PPA variant with a predominantly temporal lobe involvement in svPPA, parietal lobe involvement in lvPPA, and frontal lobe involvement in nfvPPA. Separate data for object and action naming in PPA variants are provided. The obtained results mainly correspond to the current understanding of language processing and indicate that the evaluation of language impairments is preferable for each PPA variant separately. A further analysis of larger cohorts of patients is necessary to confirm these preliminary results.

[Neurological manifestations of hypoparathyroidism: diagnostic difficulties. Case report]

Hypoparathyroidism is a rare condition characterized by reduced production of parathyroid hormone or tissue resistance which leads to hypocalcemia and hyperphosphatemia. Neurological manifestations often occur as the first symptoms of hypoparathyroidism and are characterized by a wide variety of symptoms of both the central and peripheral nervous systems dysfunction, which requires a differential diagnosis with a wide range of neurological diseases. Two clinical cases illustrating the features of subacute and chronic hypoparathyroidism are presented. In the case of subacute hypoparathyroidism, a young woman presented with severe tetany involving the oculomotor muscles (paroxysmal strabismus), laryngeal muscles (respiratory stridor), body muscles (opisthotonus, «obstetrician's hand») and the development of secondary myopathy. In another case with a long-term chronic course of postoperative hypoparathyroidism, the patient's adaptation to severe hypocalcemia was noted; the clinical features were dominated by cerebral syndromes due to brain structures calcification (Fahr's syndrome). Possible reasons for late diagnosis of hypoparathyroidism, the importance of active detection of symptoms of neuromuscular hyperexcitability and laboratory testing of phosphorus and calcium metabolism are discussed.

Analysis of ADORA2A, MTA1, PTGDS, PTGS2, NSF, and HNMT Gene Expression Levels in Peripheral Blood of Patients with Early Stages of Parkinson's Disease

Parkinson's disease (PD) is a common chronic, age-related neurodegenerative disease. This disease is characterized by a long prodromal period. In this context, it is important to search for the genes and mechanisms that are involved in the development of the pathological process in the earliest stages of the disease. Published data suggest that blood cells, particularly lymphocytes, may be a model for studying the processes that occur in the brain in PD. Thus, in the present work, we performed an analysis of changes in the expression of the genes ADORA2A, MTA1, PTGDS, PTGS2, NSF, and HNMT in the peripheral blood of patients with early stages of PD (stages 1 and 2 of the Hoehn-Yahr scale). We found significant and PD-specific expression changes of four genes, i.e., MTA1, PTGS2, NSF, and HNMT, in the peripheral blood of patients with early stages of PD. These genes may be associated with PD pathogenesis in the early clinical stages and can be considered as potential candidate genes for this disease. Altered expression of the ADORA2A gene in treated PD patients may indicate that this gene is involved in processes affected by antiparkinsonian therapy.

Mitochondrial Dysfunction in Dopaminergic Neurons Derived from Patients with LRRK2- and SNCA-Associated Genetic Forms of Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disease. Some cases of PD may be caused by genetic factors, among which mutations in the LRRK2 and SNCA genes play an important role. To develop effective neuroprotective strategies for PD, it is important to diagnose the disease at the earliest stages of the neurodegenerative process. Therefore, the detection of diagnostic and prognostic markers of Parkinson's disease (PD) is an urgent medical need. Advances in induced pluripotent stem cell (iPSC) culture technology provide new opportunities for the search for new biomarkers of PD and its modeling in vitro. In our work, we used a new technology for multiplex profiling of gene expression using barcoding on the Nanostring platform to assess the activity of mitochondrial genes on iPSC-derived cultures of dopaminergic neurons obtained from patients with LRRK2- and SNCA-associated genetic forms PD and a healthy donor. Electron microscopy revealed ultrastructural changes in mitochondria in both LRRK2 and SNCA mutant cells, whereas mitochondria in cells from a healthy donor were normal. In a culture with the SNCA gene mutation, the ratio of the area occupied by mitochondria to the total area of the cytoplasm was significantly lower than in the control and in the line with the LRRK2 gene mutation. Transcriptome analysis of 105 mitochondria proteome genes using the Nanostring platform revealed differences between the diseased and normal cells in the activity of genes involved in respiratory complex function, the tricarboxylic acid cycle, ATP production, mitochondria-endoplasmic reticulum interaction, mitophagy, regulation of calcium concentration, and mitochondrial DNA replication.

Establishing an online resource to facilitate global collaboration and inclusion of underrepresented populations: Experience from the MJFF Global Genetic Parkinson's Disease Project

Parkinson's disease (PD) is the fastest-growing neurodegenerative disorder, currently affecting ~7 million people worldwide. PD is clinically and genetically heterogeneous, with at least 10% of all cases explained by a monogenic cause or strong genetic risk factor. However, the vast majority of our present data on monogenic PD is based on the investigation of patients of European White ancestry, leaving a large knowledge gap on monogenic PD in underrepresented populations. Gene-targeted therapies are being developed at a fast pace and have started entering clinical trials. In light of these developments, building a global network of centers working on monogenic PD, fostering collaborative research, and establishing a clinical trial-ready cohort is imperative. Based on a systematic review of the English literature on monogenic PD and a successful team science approach, we have built up a network of 59 sites worldwide and have collected information on the availability of data, biomaterials, and facilities. To enable access to this resource and to foster collaboration across centers, as well as between academia and industry, we have developed an interactive map and online tool allowing for a quick overview of available resources, along with an option to filter for specific items of interest. This initiative is currently being merged with the Global Parkinson's Genetics Program (GP2), which will attract additional centers with a focus on underrepresented sites. This growing resource and tool will facilitate collaborative research and impact the development and testing of new therapies for monogenic and potentially for idiopathic PD patients.

Case report: A novel CACNA1S mutation associated with hypokalemic periodic paralysis

Background

Hypokalemic periodic paralysis (HypoKPP) is a rare neuromuscular genetic disorder causing recurrent episodes of flaccid paralysis. Most cases are associated with CACNA1S mutation, causing defect of calcium channel and subsequent impairment of muscle functions. Due to defined management approaches early diagnosis is crucial for promptly treatment and prevention new attacks.

Materials and methods

We report a case of HypoKPP associated with previously unreported mutation in CACNA1S gene (p.R900M). Molecular modeling of CaV1.1 was applied to evaluate its pathogenicity.

Results

As a patient referred between attacks neurological status, laboratory and neurophysiological examination were unremarkable. Molecular modeling predicted that the p.R900M mutation affects the process of calcium channels activation.

Conclusion

Novel CACNA1S mutation, associated with HypoKPP was identified. Monte-Carlo energy minimization of the CaV1.1 model supported the association of this mutation with this disease.

Neuronal Hyperactivation in EEG Data during Cognitive Tasks Is Related to the Apolipoprotein J/Clusterin Genotype in Nondemented Adults

The clusterin (CLU) rs11136000 CC genotype is a probable risk factor for Alzheimer's disease (AD). CLU, also known as the apolipoprotein J gene, shares certain properties with the apolipoprotein E (APOE) gene with a well-established relationship with AD. This study aimed to determine whether the electrophysiological patterns of brain activation during the letter fluency task (LFT) depend on CLU genotypes in adults without dementia. Previous studies have shown that LFT performance involves activation of the frontal cortex. We examined EEG alpha1 and alpha2 band desynchronization in the frontal regions during the LFT in 94 nondemented individuals stratified by CLU (rs11136000) genotype. Starting at 30 years of age, CLU CC carriers exhibited more pronounced task-related alpha2 desynchronization than CLU CT&TT carriers in the absence of any differences in LFT performance. In CLU CC carriers, alpha2 desynchronization was significantly correlated with age. Increased task-related activation in individuals at genetic risk for AD may reflect greater "effort" to perform the task and/or neuronal hyperexcitability. The results show that the CLU genotype is associated with neuronal hyperactivation in the frontal cortex during cognitive tasks performances in nondemented individuals, suggesting systematic vulnerability of LFT related cognitive networks in people carrying unfavorable CLU alleles.

[Gerstmann-Sträussler disease: a familial case with common PRNP mutation and atypical features]

Gerstmann-Sträussler disease (GSD) is a very rare autosomal dominant late-onset neurodegenerative disorder related to prion protein gene PRNP. Mutation p.Pro102Leu produces about 80% of cases, which are often named GSD-102. DNA testing provides exact diagnosis. In the presented Russian family there were 3 patients: a female index case, age 32 years, her brother, age 37 years (age of onset in both is 27 years) and their deceased father (onset in 35 years, death in 44 years). GSD was not suspected until whole exome sequencing in the female detected PRNP mutation p.Pro102Leu confirmed in her and in the brother by Sanger sequencing. Atypical features of the case are: early onset in siblings, absence of mental and behavioral problems in the female and in the father and mild disturbances in the brother; epilepsy in the brother; atypical onset with transient signs in the brother. Other intrafamilial differences are prevailing spastic paraparesis in the female in contrast to predominant ataxia in the brother and dysarthria absence in the female. The case illustrates GSD-102 variability, complicating clinical diagnostics.

Embracing Monogenic Parkinson's Disease: The MJFF Global Genetic PD Cohort

BACKGROUND

As gene-targeted therapies are increasingly being developed for Parkinson's disease (PD), identifying and characterizing carriers of specific genetic pathogenic variants is imperative. Only a small fraction of the estimated number of subjects with monogenic PD worldwide are currently represented in the literature and availability of clinical data and clinical trial-ready cohorts is limited.

OBJECTIVE

The objectives are to (1) establish an international cohort of affected and unaffected individuals with PD-linked variants; (2) provide harmonized and quality-controlled clinical characterization data for each included individual; and (3) further promote collaboration of researchers in the field of monogenic PD.

METHODS

We conducted a worldwide, systematic online survey to collect individual-level data on individuals with PD-linked variants in SNCA, LRRK2, VPS35, PRKN, PINK1, DJ-1, as well as selected pathogenic and risk variants in GBA and corresponding demographic, clinical, and genetic data. All registered cases underwent thorough quality checks, and pathogenicity scoring of the variants and genotype-phenotype relationships were analyzed.

RESULTS

We collected 3888 variant carriers for our analyses, reported by 92 centers (42 countries) worldwide. Of the included individuals, 3185 had a diagnosis of PD (ie, 1306 LRRK2, 115 SNCA, 23 VPS35, 429 PRKN, 75 PINK1, 13 DJ-1, and 1224 GBA) and 703 were unaffected (ie, 328 LRRK2, 32 SNCA, 3 VPS35, 1 PRKN, 1 PINK1, and 338 GBA). In total, we identified 269 different pathogenic variants; 1322 individuals in our cohort (34%) were indicated as not previously published.

CONCLUSIONS

Within the MJFF Global Genetic PD Study Group, we (1) established the largest international cohort of affected and unaffected individuals carrying PD-linked variants; (2) provide harmonized and quality-controlled clinical and genetic data for each included individual; (3) promote collaboration in the field of genetic PD with a view toward clinical and genetic stratification of patients for gene-targeted clinical trials. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Genetic Variant in GRM1 Underlies Congenital Cerebellar Ataxia with No Obvious Intellectual Disability

Metabotropic glutamate receptor 1 (mGluR1) plays a crucial role in slow excitatory postsynaptic conductance, synapse formation, synaptic plasticity, and motor control. The GRM1 gene is expressed mainly in the brain, with the highest expression in the cerebellum. Mutations in the GRM1 gene have previously been known to cause autosomal recessive and autosomal dominant spinocerebellar ataxias. In this study, whole-exome sequencing of a patient from a family of Azerbaijani origin with a diagnosis of congenital cerebellar ataxia was performed, and a new homozygous missense mutation in the GRM1 gene was identified. The mutation leads to the homozygous amino acid substitution of p.Thr824Arg in an evolutionarily highly conserved region encoding the transmembrane domain 7, which is critical for ligand binding and modulating of receptor activity. This is the first report in which a mutation has been identified in the last transmembrane domain of the mGluR1, causing a congenital autosomal recessive form of cerebellar ataxia with no obvious intellectual disability. Additionally, we summarized all known presumable pathogenic genetic variants in the GRM1 gene to date. We demonstrated that multiple rare variants in the GRM1 underlie a broad diversity of clinical neurological and behavioral phenotypes depending on the nature and protein topology of the mutation.

[Diagnosis and treatment of early forms of cognitive impairment: possibilities of influencing neuronal energy metabolism. Resolution of the Council of Experts]

Diagnosis and treatment of early forms of cognitive impairment: possibilities of influencing neuronal energy metabolism. Resolution of the Council of Experts.

[Cognitive impairment and tactics of using the drug Cerebrolysin. Resolution of the International Council of Experts (May 12, 2023)]

The aging of the population and the associated increase in the share of cognitive impairments in the structure of a wide range of diseases are a serious challenge for modern healthcare. Difficulties in the treatment of cognitive disorders are determined by many factors, including the age of patients, comorbidity, forced polypragmasia and the adequacy of the dosage of drugs that restore cognitive activity. The experts discussed information about the therapeutic potential of the drug Cerebrolysin in the treatment of cognitive disorders of various origins, stated significant experience of its effective and safe use in many clinical studies in mild and moderate forms of dementia. At the same time, there was a lack of consistent and systematic data on the dosage regimen, frequency, and duration of use of the drug in different forms of cognitive impairment and the degree of their severity. The aim of the international council of experts was to determine the optimal dosage regimens of the drug Cerebrolysin in patients with various etiologies and severity of cognitive impairment. The result of the work was the approval of a unified scheme for the use of the drug Cerebrolysin, considering the severity of the disease and its duration.

[Experience of staged and simultaneous bilateral thalamotomy using MR-guided focused ultrasound in the treatment of essential tremor]

OBJECTIVE

To show that effective and safe bilateral MR-guided focused ultrasound (MRgFUS) treatment of essential tremor (ET) is achievable.

MATERIAL AND METHODS

Four male patients underwent bilateral thalamotomy. Two patients underwent staged thalamotomy, with the ≥12 month interval between operations. Two patients underwent simultaneous bilateral thalamotomy.

RESULTS

After six months, all patients noted a significant reduction in symptoms on both sides: when assessing tremors with the Clinical Rating Scale for Tremor, the severity of hyperkinesis decreased by 57.5-69.7%. We did not observe any complications in any of the cases.

CONCLUSION

Our experience indicates that simultaneous bilateral MRI-guided focused ultrasound treatment of ET can be performed safely and effectively. Further research is necessary to estimate the effectiveness and adverse effect rates.

[Oral disease-modifying therapy for adult patients with spinal muscular atrophy type 2]

Disease modifying therapy for adult patients with SMA still raises certain questions regarding its effectiveness, given the long-term chronic process with often significant neurological deficits at the time of initiation of therapy. This paper presents three clinical cases of adult sitter patients with SMA type 2, who began risdiplam therapy 16.5-41 years after the disease onset. All patients have been receiving therapy since 2020, at the time of observation for 2.5-3 years. All patients showed subjective and objective (using specialized scales) improvement during long-term therapy with risdiplam. In addition to an increase in muscle strength, mainly in the proximal and distal parts of the arms, several non-motor effects were also noted (including improved swallowing and breathing), which cannot be recorded using scales. No adverse events were recorded during therapy.

[Cerebellar degeneration associated with HIV infection]

OBJECTIVE

To describe the features of the clinical presentation and evaluate the incidence of HIV-associated cerebellar degeneration in patients with progressive cerebellar ataxia.

MATERIAL AND METHODS

Three hundred and seventy-seven patients with progressive cerebellar ataxia were studied. Brain MRI study, assessment by the Scale for the Assessment and Rating of Ataxia (SARA), screening for cognitive impairment by the Montreal Cognitive Assessment Scale (MoCA) were performed. In patients with HIV infection, autoimmune, deficient and other causes of ataxia, as well as opportunistic infections, multiple system atrophy and frequent forms of hereditary spinocerebellar ataxias were excluded.

RESULTS

Five patients (1.3%) were identified with a combination of cerebellar ataxia and HIV infection (2 men, 3 women, aged 31 to 52 years). The median duration of HIV infection was 5 years, the duration of ataxia was 1 year. In the clinical findings, in addition to progressive ataxia, pyramidal signs, dysphagia, less often ophthalmoparesis, dystonia, postural hand tremor, affective and mild cognitive impairment were observed. In three patients, brain MRI revealed signs of olivopontocerebellar atrophy, two patients had isolated cerebellar degeneration (mainly of the vermis). All patients received combination of antiretroviral therapy in various regimens, but despite this, ataxia was progressive.

CONCLUSION

HIV infection is a rare cause of cerebellar degeneration. This diagnosis remains a diagnosis of exclusion to this day. Cerebellar degeneration can occur and progress even after achieving a stable remission of HIV infection while taking highly active antiretroviral therapy.

Deconvolution of B cell receptor repertoire in multiple sclerosis patients revealed a delay in tBreg maturation

Background

B lymphocytes play a pivotal regulatory role in the development of the immune response. It was previously shown that deficiency in B regulatory cells (Bregs) or a decrease in their anti-inflammatory activity can lead to immunological dysfunctions. However, the exact mechanisms of Bregs development and functioning are only partially resolved. For instance, only a little is known about the structure of their B cell receptor (BCR) repertoires in autoimmune disorders, including multiple sclerosis (MS), a severe neuroinflammatory disease with a yet unknown etiology. Here, we elucidate specific properties of B regulatory cells in MS.

Methods

We performed a prospective study of the transitional Breg (tBreg) subpopulations with the CD19+CD24highCD38high phenotype from MS patients and healthy donors by (i) measuring their content during two diverging courses of relapsing-remitting MS: benign multiple sclerosis (BMS) and highly active multiple sclerosis (HAMS); (ii) analyzing BCR repertoires of circulating B cells by high-throughput sequencing; and (iii) measuring the percentage of CD27+ cells in tBregs.

Results

The tBregs from HAMS patients carry the heavy chain with a lower amount of hypermutations than tBregs from healthy donors. The percentage of transitional CD24highCD38high B cells is elevated, whereas the frequency of differentiated CD27+ cells in this transitional B cell subset was decreased in the MS patients as compared with healthy donors.

Conclusions

Impaired maturation of regulatory B cells is associated with MS progression.

Genetic association of apolipoprotein E genotype with EEG alpha rhythm slowing and functional brain network alterations during normal aging

The ε4 allele of the apolipoprotein E (APOE4+) genotype is a major genetic risk factor for Alzheimer’s disease (AD), but the mechanisms underlying its influence remain incompletely understood. The study aimed to investigate the possible effect of the APOE genotype on spontaneous electroencephalogram (EEG) alpha characteristics, resting-state functional MRI (fMRI) connectivity (rsFC) in large brain networks and the interrelation of alpha rhythm and rsFC characteristics in non-demented adults during aging. We examined the EEG alpha subband’s relative power, individual alpha peak frequency (IAPF), and fMRI rsFC in non-demented volunteers (age range 26–79 years) stratified by the APOE genotype. The presence of the APOE4+ genotype was associated with lower IAPF and lower relative power of the 11–13 Hz alpha subbands. The age related decrease in EEG IAPF was more pronounced in the APOE4+ carriers than in the APOE4+ non-carriers (APOE4-). The APOE4+ carriers had a stronger fMRI positive rsFC of the interhemispheric regions of the frontoparietal, lateral visual and salience networks than the APOE4– individuals. In contrast, the negative rsFC in the network between the left hippocampus and the right posterior parietal cortex was reduced in the APOE4+ carriers compared to the non-carriers. Alpha rhythm slowing was associated with the dysfunction of hippocampal networks. Our results show that in adults without dementia APOE4+ genotype is associated with alpha rhythm slowing and that this slowing is age-dependent. Our data suggest predominant alterations of inhibitory processes in large-scale brain network of non-demented APOE4+ carriers. Moreover, dysfunction of large-scale hippocampal network can influence APOE-related alpha rhythm vulnerability.

Generation of induced pluripotent stem cell line, ICGi033-A, by reprogramming peripheral blood mononuclear cells from a patient with Huntington's disease

Huntington's disease (HD) is a hereditary autosomal dominant neurodegenerative disease caused by the polyglutamine stretch expansion in the huntingtin (HTT) protein. In HD, dysregulation of multiple cellular processes occurs, resulting in the death of medium spiny neurons of striatum. A line of induced pluripotent stem cells (iPSCs) ICGi033-A was obtained from peripheral blood mononuclear cells of a patient carrying 77 CAG repeats in the HTT gene. The iPSCs express pluripotency markers, have a normal karyotype, and differentiate into three germ layers: endoderm, ectoderm, mesoderm.

Novel genes bearing mutations in rare cases of early-onset ataxia with cerebellar hypoplasia

We propose an approach for the identification of mutant genes for rare diseases in single cases of unknown etiology. All genes with rare biologically significant variants sorted from individual exome data are tested further for profiling of their spatial-temporal and cell/tissue specific expression compared to that of their paralogs. We developed a simple bioinformatics tool ("Essential Paralogue by Expression" (EPbE)) for such analysis. Here, we present rare clinical forms of early ataxia with cerebellar hypoplasia. Using whole-exome sequencing and the EPbE tool, we identified two novel mutant genes previously not associated with congenital human diseases. In Family I, the unique missense mutation (p.Lys258Glu) was found in the LRCH2 gene inherited in an X-linked manner. p.Lys258Glu occurs in the evolutionarily invariant site of the leucine-rich repeat domain of LRCH2. In Family II and Family III, the identical genetic variant was found in the CSMD1 gene inherited as an autosomal-recessive trait. The variant leads to amino acid substitution p.Gly2979Ser in a highly conserved region of the complement-interacting domain of CSMD1. The LRCH2 gene for Family I patients (in which congenital cerebellar hypoplasia was associated with demyelinating polyneuropathy) is expressed in Schwann and precursor Schwann cells and predominantly over its paralogous genes in the developing cerebellar cortex. The CSMD1 gene is predominantly expressed over its paralogous genes in the cerebellum, specifically in the period of late childhood. Thus, the comparative spatial-temporal expression of the selected genes corresponds to the neurological manifestations of the disease.

Visual analysis of nigrosome-1 in the differential diagnosis of Parkinson's disease and essential tremor

Differentiation between Parkinson’s disease, especially in its early stages, and essential tremor, which is a phenotypically similar movement disorder, still remains an unsolved challenge for neurology. The aim of this study was to assess the diagnostic significance of nigrosome imaging (nigrosomes are dopaminergic neuron clusters in the substantia nigra of the midbrain) using 3T high-resolution SW-MRI. The study was conducted in 20 patients with Parkinson’s disease and 10 patients with essential tremor. Visual analysis of the acquired nigrosome-1 images was performed using a 4-point ordinal rating scale. Differences in sex, age and duration of the disease were calculated using the Fisher exact test and the Mann–Whitney U test. The diagnostic value of the method was assessed using Pearson’s chisquared test. Nigrosome-1 was bilaterally or unilaterally absent in 70% of parkinsonian patients. Less specific changes to the substantia nigra (SN) were observed in two more parkinsonian patients (10%), whose nigrosome-1 appeared reduced in size. By contrast, nigrosome-1 was bilaterally intact in all patients (100%) with essential tremor (p < 0.001). Our preliminary findings demonstrate the high potential of noninvasive nigrosome-1 imaging in the differential diagnosis of Parkinson’s disease and essential tremor.

Reproducibility of developmental neuroplasticity in in vitro brain tissue models

The current prevalence of neurodevelopmental, neurodegenerative diseases, stroke and brain injury stimulates studies aimed to identify new molecular targets, to select the drug candidates, to complete the whole set of preclinical and clinical trials, and to implement new drugs into routine neurological practice. Establishment of protocols based on microfluidics, blood-brain barrier- or neurovascular unit-on-chip, and microphysiological systems allowed improving the barrier characteristics and analyzing the regulation of local microcirculation, angiogenesis, and neurogenesis. Reconstruction of key mechanisms of brain development and even some aspects of experience-driven brain plasticity would be helpful in the establishment of brain in vitro models with the highest degree of reliability. Activity, metabolic status and expression pattern of cells within the models can be effectively assessed with the protocols of system biology, cell imaging, and functional cell analysis. The next generation of in vitro models should demonstrate high scalability, 3D or 4D complexity, possibility to be combined with other tissues or cell types within the microphysiological systems, compatibility with bio-inks or extracellular matrix-like materials, achievement of adequate vascularization, patient-specific characteristics, and opportunity to provide high-content screening. In this review, we will focus on currently available and prospective brain tissue in vitro models suitable for experimental and preclinical studies with the special focus on models enabling 4D reconstruction of brain tissue for the assessment of brain development, brain plasticity, and drug kinetics.

Ultrasound imaging of vagus nerves in patients with Parkinson's disease

Parkinson’s disease (PD) is a neurodegenerative multisystem disorder characterized by pathologic α-synuclein aggregation affecting, among other things, vagal fibers. The aim of this study was to investigate the cross-sectional area (CSA) of the vagus nerve (VN) in patients with PD using ultrasound imaging. The study was conducted in 32 patients with PD (15 men and 17 women; mean age 58 ± 10 years) and 32 healthy controls comparable with the main group in terms of sex and age. All study participants underwent ultrasound examination of the VN using a high-resolution transducer. Left VN CSA was significantly smaller in patients with PD than in the control group (1.78 ± 0.52 mm2 vs 2.11 ± 0.41 mm2; р = 0.007). A similar result was obtained for right VN CSA at the trend level. ROC analysis demonstrated that the threshold CSA value of < 2.10 mm2 for the left VN has low diagnostic sensivity (59%) for VN atrophy in patients with PD. Right VN CSA was significantly larger than left VN CSA in both groups (p < 0.001). The analysis of the PD group did not reveal any associations between VN CSA and age, duration and stage of the disease, motor (UPDRS III) and non-motor (NMSQ) scores. Patients with akinetic-rigid form of PD had smaller left VN CSA than patients with the mixed form of the disease (р < 0.05). A moderate inverse correlation was established between left VN CSA and the area of substantia nigra hyperechogenicity on both sides (р < 0.04); for the right VN a similar correlation was established at the trend level. High-resolution ultrasound of patients with PD demonstrated atrophy of the VN and the association of VN CSA with the clinical form of the disease and the ultrasound features of the substantia nigra.

[The influence of parasomnia on clinical and functional characteristics of extrapyramidal disorders]

OBJECTIVE

To compare clinical and functional features of the essential tremor (ET) and Parkinson's disease (PD) with- or without rapid eye movement (REM) sleep behavior disorder (RBD).

MATERIAL AND METHODS

Sixty patients with PD and 52 patients with ET were examined. Cognitive functions, anxiety, asthenia and depression, autonomic disorders and sleep disorders were assessed with scales and questionnaires. All patients underwent polysomnography (PSG). Based on the results of PSG, patients were divided by the presence or absence of parasomnia, known as REM sleep behavior disorder.

RESULTS

Patients with PD and ET suffering from RBD were more likely to be overweight, more likely to develop cognitive impairment, obstructive sleep apnea, and emotional disorders. In addition, presence of RBD has adverse effects on the sleep structure. The profile of memory, attention, psychoemotional and sleep disorders in patients with PD and ET had common features, which suggests that it is RPBDH that affects the change in the clinical picture.

CONCLUSION

Presence of RBD aggravates non-motor manifestations of such extrapyramidal diseases as PD and ET. On the one hand it helps to predict the course of the disease, on the other hand let us suspect RBD when we see non-motor symptoms worsening.

Mitochondrial Disorders in Alzheimer's Disease

Alzheimer's disease is the most common age-related neurodegenerative disease. Understanding of its etiology and pathogenesis is constantly expanding. Thus, the increasing attention of researchers is directed to the study of the role of mitochondrial disorders. In addition, in recent years, the concept of Alzheimer's disease as a stress-induced disease has begun to form more and more actively. The stress-induced damage to the neuronal system can trigger a vicious circle of pathological processes, among which mitochondrial dysfunctions have a significant place, since mitochondria represent a substantial component in the anti-stress activity of the cell. The study of mitochondrial disorders in Alzheimer's disease is relevant for at least two reasons: first, as important pathogenetic component in this disease; second, due to vital role of mitochondria in formation of the body resistance to various conditions, including stressful ones, throughout the life. This literature review analyzes the results of a number of recent studies assessing potential significance of the mitochondrial disorders in Alzheimer's disease. The probable mechanisms of mitochondrial disorders associated with the development of this disease are considered: bioenergetic dysfunctions, changes in mitochondrial DNA (including assessment of the significance of its haplogroup features), disorders in the dynamics of these organelles, oxidative damage to calcium channels, damage to MAM complexes (membranes associated with mitochondria; mitochondria-associated membranes), disruptions of the mitochondrial quality control system, mitochondrial permeability, etc. The issues of the "primary" or "secondary" mitochondrial damage in Alzheimer's disease are discussed. Potentials for the development of new methods for diagnosis and therapy of mitochondrial disorders in Alzheimer's disease are considered.

STIM2 Mediates Excessive Store-Operated Calcium Entry in Patient-Specific iPSC-Derived Neurons Modeling a Juvenile Form of Huntington's Disease

Huntington's disease (HD) is a severe autosomal-dominant neurodegenerative disorder caused by a mutation within a gene, encoding huntingtin protein. Here we have used the induced pluripotent stem cell technology to produce patient-specific terminally differentiated GABA-ergic medium spiny neurons modeling a juvenile form of HD (HD76). We have shown that calcium signaling is dramatically disturbed in HD76 neurons, specifically demonstrating higher levels of store-operated and voltage-gated calcium uptakes. However, comparing the HD76 neurons with the previously described low-repeat HD models, we have demonstrated that the severity of calcium signaling alterations does not depend on the length of the polyglutamine tract of the mutant huntingtin. Here we have also observed greater expression of huntingtin and an activator of store-operated calcium channels STIM2 in HD76 neurons. Since shRNA-mediated suppression of STIM2 decreased store-operated calcium uptake, we have speculated that high expression of STIM2 underlies the excessive entry through store-operated calcium channels in HD pathology. Moreover, a previously described potential anti-HD drug EVP4593 has been found to attenuate high levels of both huntingtin and STIM2 that may contribute to its neuroprotective effect. Our results are fully supportive in favor of the crucial role of calcium signaling deregulation in the HD pathogenesis and indicate that the cornerstone of excessive calcium uptake in HD-specific neurons is a calcium sensor and store-operated calcium channels activator STIM2, which should become a molecular target for medical treatment and novel neuroprotective drug development.

Brain atrophy patterns in patients with frontotemporal dementia: voxel-based morphometry

Frontotemporal dementia (FTD) is a neurodegenerative disorder characterized by language and behaviour deficits, which is considered the second most common cause of early-onset dementia. Detection of brain atrophy patterns is important for FTD diagnosis. However, the visual assessment of magnetic resonance imaging data may not be sensitive enough requiring the use of objective gray matter (GM) volume determination method. The study was aimed to assess the GM atrophy pattern in patients with FTD compared to control group patients using voxel-based morphometry (VBM). The study included 16 patients with FTD (12 patients with nonfluent agrammatic variant primary progressive aphasia (nfvPPA), three patients with behavioral variant of FTD, and one patient with logopenic variant PPA) and 10 healthy volunteers. VBM of patients with FTD and healthy controls revealed three significant (pFWE-corr < 0.05) atrophy areas in the left inferior frontal, left fusiform, and left supramarginal gyri. Taking into account the predominance of patients with nfvPPA in the group of FTD patients, the additional VBM of this group and control group was carried out, which revealed a distinct atrophy pattern: the reduced GM volume was detected in the left inferior frontal and left middle frontal gyri (pFWE-corr < 0.05). The results obtained indicate that regardless of the clinical variant, there is a certain atrophy pattern characteristic of FTD, which involves both frontotemporal areas and parietal lobe. The example of nfvPPA shows that each variant of the disease is associated with distinct localization of atrophy.

[C9orf72-associated frontotemporal dementia in the Russian population]

OBJECTIVE

To evaluate the frequency of C9orf72-associated frontotemporal dementia (FTD) in the Russian population and to study clinical features of GGGGCC-repeat expansion carriers.

MATERIAL AND METHODS

Twenty-eight patients with FTD are included in the study: 15 with a behavioral variant of FTD (bvFTD) and 13 with a agrammatic/non-fluent variant of primary progressive aphasia (avPPA). The mean age was 62 years (34-80), the mean disease duration was 4 years (1-10). The positive family history was noted in 46% of cases. DNA diagnosis was performed using repeat-primed polymerase chain reaction.

RESULTS

The frequency of the C9orf72 repeat expansion in patients with FTD was 14%, in patients with bvFTD 20%, in patients with avPPA 8%. The mean age of disease onset in the expansion carriers was 63 (55-75) years. The frequency of the C9orf72 repeats expansion in familial FTD cases was 31%, in sporadic cases 7%. bvFTD with parkinsonian syndrome was noted in two out of four cases, bvFTD with amyotrophic lateral sclerosis (ALS) was shown in one case, avPPA with ALS was shown in one case. One female patient with bvFTD with parkinsonian syndrome presented with cognitive fluctuations that required a differential diagnosis with Lewy body disease.

CONCLUSION

This is the first study of the genetic structure of FTD in the Russian population. The prevalence and clinical characteristics of C9orf72-associated FTD were defined, in particular, the spectrum of motor symptoms was shown along with behavioral and aphasic disturbances. DNA diagnosis plays an important role in confirming the diagnosis and selection of patients for potential disease-modifying treatment.

C9orf72 Gene Expression in Frontotemporal Dementia and Amyotrophic Lateral Sclerosis

We studied the expression of C9orf72 gene in pathologies associated with hexanucleotide repeats expansion in this gene: frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). The study included 7 patients with hexanucleotide repeats expansion in the C9orf72 gene and 9 patients of the control group. The expression of C9orf72 mRNA was evaluated in blood leukocytes by real-time PCR. Methylation of CpG-sites in C9orf72 promotor region was evaluated by DNA sequencing after bisulfite conversion. A 2-fold decrease in the C9orf72 gene expression was found in patients with hexanucleotide repeats expansion in comparison with controls, though the difference did not reach statistical significance due to small sample size. The highest expression was shown for ALS in comparison with FTD and FTD-ALS phenotype. A trend to inverse correlation between C9orf72 mRNA level and promoter methylation of this gene as well as between mRNA level and age of disease onset was demonstrated.

Parkinson's Disease: Available Clinical and Promising Omics Tests for Diagnostics, Disease Risk Assessment, and Pharmacotherapy Personalization

Parkinson's disease is the second most frequent neurodegenerative disease, representing a significant medical and socio-economic problem. Modern medicine still has no answer to the question of why Parkinson's disease develops and whether it is possible to develop an effective system of prevention. Therefore, active work is currently underway to find ways to assess the risks of the disease, as well as a means to extend the life of patients and improve its quality. Modern studies aim to create a method of assessing the risk of occurrence of Parkinson's disease (PD), to search for the specific ways of correction of biochemical disorders occurring in the prodromal stage of Parkinson's disease, and to personalize approaches to antiparkinsonian pharmacotherapy. In this review, we summarized all available clinically approved tests and techniques for PD diagnostics. Then, we reviewed major improvements and recent advancements in genomics, transcriptomics, and proteomics studies and application of metabolomics in PD research, and discussed the major metabolomics findings for diagnostics and therapy of the disease.

[Clinical and morphological analysis of a caseof Parkinson's disease]

Parkinson's disease (PD) is a neurodegenerative disease that belongs to a group of cerebral proteinopathies. The main pathomorphological signs of PD are neuronal degeneration in the midbrain substantia nigra and detection of pathological forms of the synaptic protein α-synuclein in the nigral neurons. At the same time, the pathological forms of α-synuclein in this disease have been recently shown to accumulate in the cells of not only the central, but also peripheral autonomic nervous system. The paper provides a clinical and morphological description of a PD case in a 70-year-old patient, which demonstrates that there are typical α-synuclein-positive inclusions in the brain regions (substantia nigra, caudate nucleus, and frontal cortex), salivary glands and colon. The systemic nature of α-synucleinopathy in PD is important in both clarifying the pathogenesis of the disease and elaborating new approaches to its diagnosis and, in the future, to targeted therapy.

[Genetic Diversity in Frontotemporal Dementia]

Frontotemporal dementia is a progressive neurodegenerative disorder with high clinical, genetic, and pathomorphological diversity It is the third most common cause of dementia in all ages and the most common cause of early onset dementia (below 65). Despite its multifactorial nature, up to 40% of patients have a family history where the autosomal dominant inheritance type is seen in a quarter of cases. In this review, we describe key genes whose mutations can result in the development of frontotemporal dementia, the possible pathogenic mechanisms of the degenerative process, and provide information on the clinical features of the disease for different genetic variants. Special emphasis is placed on the frontotemporal dementia phenotype that is associated with amyotrophic lateral sclerosis.

Thymoquinone as a Potential Neuroprotector in Acute and Chronic Forms of Cerebral Pathology

Thymoquinone is one of the main active components of the essential oil from black cumin (Nigella sativa) seeds. Thymoquinone exhibits a wide range of pharmacological activities, including neuroprotective action demonstrated in the models of brain ischemia/reperfusion, Alzheimer's and Parkinson's diseases, and traumatic brain injury. The neuroprotective effect of thymoquinone is mediated via inhibition of lipid peroxidation, downregulation of proinflammatory cytokines, maintenance of mitochondrial membrane potential, and prevention of apoptosis through inhibition of caspases-3, -8, and -9. Thymoquinone-based mitochondria-targeted antioxidants are accumulated in the mitochondria and exhibit neuroprotective properties in nanomolar concentrations. Thymoquinone reduces the negative effects of acute and chronic forms of brain pathologies. The mechanisms of the pharmacological action of thymoquinone and its chemical derivatives require more comprehensive studying. In this paper, we formulated the prospects of application of thymoquinone and thymoquinone-based drugs in the therapy of neurodegenerative diseases.

Generation of induced pluripotent stem cell line ICGi018-A from peripheral blood mononuclear cells of a patient with Huntington's disease

Huntington's disease (HD) is an autosomal dominant neurodegenerative disease caused by CAG repeat expansion in the HTT gene. HD patient-specific induced pluripotent stem cells (iPSCs) represent an excellent model for the disease study. We generated iPSC line from blood mononuclear cells of HD patient with 38 CAG repeats in the HTT exon 1 using integration free episomal plasmids expressing Yamanaka factors. The iPSC line retained the disease causing mutation and expressed pluripotency markers. It also displayed a normal karyotype and the ability to differentiate into derivatives of three germ layers.

[Epigenetic regulation of clinical manifestations of Friedreich's disease]

AIM

To study a methylation profile of FXN gene and its influence on the clinical phenotype of Friedreich's desease (FD).

MATERIAL AND METHODS

The methylation pattern was analyzed in 17 patients with FD. Forty-five CpG-sites in the promoter region and the region of intron 1 of FXN: before the GAA-expansion (UP-GAA) and after the GAA-expansion (DOWN-GAA), were studied.

RESULTS

Correlations between the methylation level of CpG-sites in UP-GAA and DOWN-GAA and the number of GAA repeats in both expanded FXN alleles in patients with FD were found. An analysis revealed an earlier onset and a more severe course of FD in cases with hypermethylation of several CpG-sites in the UP-GAA region. The correlation between the methylation pattern and the presence of extraneural manifestations of FD was also revealed. In FD patients with cardiomyopathy, a hypomethylated CpG-site in the promoter region was found. In FD patients with carbohydrate metabolism disorders, two hypomethylated CpG-sites in the DOWN-GAA region were observed.

CONCLUSION

The results indicate a significant contribution of epigenetic modifications of FXN to the clinical presentation of FA.

Parkinson's Disease-Associated Changes in the Expression of Neurotrophic Factors and their Receptors upon Neuronal Differentiation of Human Induced Pluripotent Stem Cells

Parkinson's disease (PD) is a neurodegenerative pathology resulting from the degeneration of dopaminergic (DA) neurons in the substantia nigra (SN). Neurotrophic factors (NTFs) and their receptors are key regulators of the survival, differentiation, and development of neurons. However, the role of these factors in the pathogenesis of PD is still unclear. Here, we analyzed the expression of NTFs and their receptors in human induced pluripotent stem cells (iPSCs) derived from the fibroblasts of patients with PD and healthy donors (HDs). Four PD-derived iPSC lines with different mutations and three cell lines from HDs at different stages of neuronal differentiation were used for RT-qPCR analysis and ELISA. We found that the mRNA levels of most analyzed genes were altered in PD-derived cells compared with those in HD-derived cells at all stages. Importantly, irrespective of PD-associated mutations, the mRNA levels of the BDNF and GDNF genes were mostly increased or unchanged in predominantly DA terminally differentiated neurons (TDNs) compared with those in HD-derived cells. Strikingly, in contrast to BDNF and GDNF mRNA levels, BDNF and GDNF protein levels were lower in almost all PD-derived TDNs than in HD-derived cells, thus indicating the dysregulation of NTF expression at the post-transcriptional level. We suggest that this dysregulation is one of the important signs of PD development.

Generation of an induced pluripotent stem cell line, ICGi014-A, by reprogramming peripheral blood mononuclear cells from a patient with homozygous D90A mutation in SOD1 causing Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by death of motor neurons. To date, neither etiology nor pathogenesis of ALS are known, which leads to the absence of an effective treatment strategy. ALS patient-specific induced pluripotent stem cells (iPSCs) represent an excellent tool for the disease study. We obtained iPSCs line from peripheral blood mononuclear cells of the patient with homozygous Asp90Ala mutation in the SOD1 gene using non-integrating episomal vectors. The iPSCs line retained pathological genotype and expressed pluripotency markers. It also displayed a normal karyotype and the ability to differentiate into derivatives of three germ layers.

The Use of Human Induced Pluripotent Stem Cells for Testing Neuroprotective Activity of Pharmacological Compounds

Development of therapeutic preparations involves several steps, starting with the synthesis of chemical compounds and testing them in different models for selecting the most effective and safest ones to clinical trials and introduction into medical practice. Cultured animal cells (both primary and transformed) are commonly used as models for compound screening. However, cell models display a number of disadvantages, including insufficient standardization (primary cells) and disruption of cell genotypes (transformed cells). Generation of human induced pluripotent stem cells (IPSCs) offers new possibilities for the development of high-throughput test systems for screening potential therapeutic preparations with different activity spectra. Due to the capacity to differentiate into all cell types of an adult organism, IPSCs are a unique model that allows examining the activity and potential toxicity of tested compounds during the entire differentiation process in vitro. In this work, we demonstrated the efficiency of IPSCs and their neuronal derivatives for selecting substances with the neuroprotective activity using two classes of compounds - melanocortin family peptides and endocannabinoids. None of the tested compounds displayed cyto- or embryotoxicity. Both melanocortin peptides and endocannabinoids exerted neuroprotective effect in the neuronal precursors and IPSC-derived neurons subjected to hydrogen peroxide. The endocannabinoid N-docosahexaenoyl dopamine exhibited the highest neuroprotective effect (~70%) in the differentiated cultures enriched with dopaminergic neurons; the effect of melanocortin Semax was ~40%. The possibility of using other IPSC derivatives for selecting compounds with the neuroprotective activity is discussed.

[Diagnostic algorithm for autosomal recessive ataxia]

AIM

To develop a complex algorithm for autosomal recessive ataxia (ARA) diagnosis applicable for Russian patients with degenerative ataxias.

MATERIAL AND METHODS

48 patients with of presumably degenerative ataxias were examined. Clinical evaluation was performed with the use of the SARA and ICARS scales (for ataxia) and MoCA (cognitive functions), and a set of laboratory tests was carried out, including electromyography, brain MRI, and DNA analysis of mutations responsible for Friedreich's disease and spinocerebellar ataxias (SCAs) types 1, 2, 3, 6 and 17. 28 patients underwent mutation screening using a multigenic MPS panel.

RESULTS

8 patients (16.7%) with non-hereditary causes of ataxia were identified: cerebellar alcoholic degeneration (n = 6) and multiple system atrophy of cerebellar type (n = 2); 3 patients (6.3%) with genetic ataxias were identified using routine DNA tests, such as with SCA type 1, 2 and 17, and 9 (18.8%) patients with Friedreich's disease. The MPS panel enabled molecular diagnosis of ARA in 8 patients (28.6%): ataxia-telangiectasia (n = 2), SANDO syndrome (n = 2), ataxia with oculomotor apraxia type 2 (n = 1), SCAR10 (n = 1), SCAR16 (n = 1), and atypical form of neuroaxonal dystrophy (n = 1). The diagnosis was not established in 20 patients.

CONCLUSION

We have proposed an appropriate algorithm for degenerative ataxia diagnosis which is recommended to be used when examining patients with sporadic and autosomal recessive cases of the disorders with dyscoordination of movements.

Expression and Functional Properties of NMDA and GABAA Receptors during Differentiation of Human Induced Pluripotent Stem Cells into Ventral Mesencephalic Neurons

Ionotropic glutamate and GABA receptors regulate the differentiation and determine the functional properties of mature neurons. Both insufficient and excessive activity of these neurotransmission systems are associated with various nervous system diseases. Our knowledge regarding the expression profiles of these receptors and the mechanisms of their regulation during the differentiation of specialized human neuron subtypes is limited. Here the expression profiles of the NMDA and GABA_A receptor subunits were explored during in vitro differentiation of human induced pluripotent stem cells (iPSCs) into ventral mesencephalic neurons. The correlation between the neuronal maturation and the expression dynamics of these genes was investigated, and the functional activity of these receptors was assessed by calcium imaging. The role of NMDA and GABA_A receptors in neurite outgrowth and the development of spontaneous activity was analyzed using the viral transduction of neural progenitors with the reporter genes TagGFP and TagRFP. The data indicate that agonists of the investigated receptors can be employed for optimization of existing protocols for neural differentiation of iPSCs, in particular for acceleration of neuronal maturation.

A Platform for Studying Neurodegeneration Mechanisms Using Genetically Encoded Biosensors

Patient-specific induced pluripotent stem cells (iPSCs) capable of differentiation into required cell type are a promising model for studying various pathological processes and development of new therapeutic approaches. However, no conventional strategies for using iPSCs in disease research have been established yet. Genetically encoded biosensors can be used for monitoring messenger molecules, metabolites, and enzyme activity in real time with the following conversion of the registered signals in quantitative data, thus allowing evaluation of the impact of certain molecules on pathology development. In this article, we describe the development of a universal cell-based platform for studying pathological processes associated with amyotrophic lateral sclerosis. For this purpose, we have created a series of plasmid constructs for monitoring endoplasmic reticulum stress, oxidative stress, apoptosis, and Ca2+-dependent hyperexcitability and generated transgenic iPSC line carrying mutation in the superoxide dismutase 1 gene (SOD1) and healthy control cell line. Both cell lines have specific transactivator sequence required for doxycycline-controlled transcriptional activation and can be used for a single-step biosensor insertion.

[A comparative analysis of allele frequencies of rs1801133 and rs1801131 of MTHFR in patients with stroke and healthy people from the Moscow region]

AIM

To study genetic characteristics of the population of the Moscow region and analyze the association of rs1801133 and rs1801131 of MTHFR with the risk of ischemic stroke (IS).

MATERIAL AND METHODS

A sample of 170 and 115 patients with atherothrombotic and cardioembolic subtypes of IS and 360 residents of the Moscow region without IS were examined. MTHFR alleles were determined by a multiplex real-time polymerase chain reaction.

RESULTS AND CONCLUSION

No association between the frequencies of MTHFR alleles and the risk of ischemic stroke was found. The comparison of allele frequencies with those in Caucasian populations published in the dbSNP (NCBI) and 1000 Genomes Project databases revealed significant differences for rs1801133 from the EUR 1000 Genomes Project. The allele frequency data for MTHFR could increase the accuracy and reliability of the individual risk calculation for multifactorial diseases in the Russian population.

Genetic Association between Alzheimer's Disease Risk Variant of the PICALM Gene and Auditory Event-Related Potentials in Aging

Aging and genetic predisposition are major risk factors in age-related neurodegenerative disorders. The most common neurodegenerative disorder is Alzheimer's disease (AD). Genome-wide association studies (GWAS) have identified statistically significant association of the PICALM rs3851179 polymorphism with AD. The PICALM G allele increases the risk of AD, while the A allele has a protective effect. We examined the association of the PICALM rs3851179 polymorphism with parameters of the P3 component of auditory event-related potentials (ERPs) in 87 non-demented volunteers (age, 19-77 years) subdivided into two cohorts younger and older than 50 years of age. We found statistically significant association between the AD risk variant PICALM GG and increase in the P3 latency in subjects over 50 years old. The age-dependent increase in the P3 latency was more pronounced in the PICALM GG carriers than in the carriers of the PICALM AA and PICALM AG genotypes. The observed PICALM-associated changes in the neurophysiological processes indicate a decline in the information processing speed with aging due, probably, to neuronal dysfunction and subclinical neurodegeneration of the neuronal networks in the hippocampus and the frontal and parietal cortical areas. Such changes were less pronounced in the carriers of the PICALM gene A allele, which might explain the protective effect of this allele in the cognitive decline and AD development.

Molecular Pathogenesis in Huntington's Disease

Huntington's disease (HD) is a severe autosomal dominant neurodegenerative disorder characterized by a combination of motor, cognitive, and psychiatric symptoms, atrophy of the basal ganglia and the cerebral cortex, and inevitably progressive course resulting in death 5-20 years after manifestation of its symptoms. HD is caused by expansion of CAG repeats in the HTT gene, which leads to pathological elongation of the polyglutamine tract within the respective protein - huntingtin. In this review, we present a modern view on molecular biology of HD as a representative of the group of polyglutamine diseases, with an emphasis on conformational changes of mutant huntingtin, disturbances in its cellular processing, and proteolytic stress in degenerating neurons. Main pathogenetic mechanisms of neurodegeneration in HD are discussed in detail, such as systemic failure of transcription, mitochondrial dysfunction and suppression of energy metabolism, abnormalities of cytoskeleton and axonal transport, microglial inflammation, decrease in synthesis of brain-derived neurotrophic factor, etc.

Genome Editing and the Problem of Tetraploidy in Cell Modeling of the Genetic Form of Parkinsonism

The prevalent form of familial parkinsonism is caused by mutations in the LRRK2 gene encoding for the mitochondrial protein kinase. In the review, we discuss possible causes of appearance of tetraploid cells in neuronal precursors obtained from induced pluripotent stem cells from patients with the LRRK2-associated form of parkinsonism after genome editing procedure. As LRRK2 protein participates in cell proliferation and maintenance of the nuclear envelope, spindle fibers, and cytoskeleton, mutations in the LRRK2 gene can affect protein functions and lead, via various mechanisms, to the mitotic machinery disintegration and chromosomal aberration. These abnormalities can appear at different stages of fibroblast reprogramming; therefore, editing of the LRRK2 nucleotide sequence should be done during or before the reprogramming stage.

[Complex assessment of the contribution of genetic factors to the risk of ischemic stroke]

AIM

To develop a method of the complex assessment of genetic risk for ischemic stroke (IS) and evaluate its effectiveness.

MATERIAL AND METHODS

Genotyping of 182 patients with atherothrombotic and cardioembolic subtypes of IS and 360 healthy individuals of 48 single nucleotide polymorphic loci (SNP) associated with the risk of II and its subtypes was performed.

RESULTS AND CONCLUSION

In each group of SNPs, composite indicators of genetic risk of IS in groups of patients and healthy controls were identified. Differences between the calculated values of the genetic risk in these groups were significant (p <0,05). The quality of the binary classification validated by ROC-analysis confirmed the predictive potential of the proposed method of risk calculation for determining the genetic predisposition to the development of IS.