Neurogenetics最新文献

Alzheimer's disease (AD) is a slow brain degeneration disorder in which the accumulation of beta-amyloid precursor plaque and an intracellular neurofibrillary tangle of hyper-phosphorylated tau proteins in the brain have been implicated in neurodegeneration. In this study, we identified the most important genes that are unique and sensitive in the entorhinal region of the brain to target AD effectively. At first, microarrays data are selected and constructed protein-protein interaction network (PPIN) and gene regulatory network (GRN) from differentially expressed genes (DEGs) using Cytoscape software. Then, networks analysis was performed to determine hubs, bottlenecks, clusters, and signaling pathways in AD. Finally, critical genes were selected as targets for repurposing drugs. Analyzing the constructed PPIN and GRN identified CD44, ELF1, HSP90AB1, NOC4L, BYSL, RRP7A, SLC17A6, and RUVBL2 as critical genes that are dysregulated in the entorhinal region of AD suffering patients. The functional enrichment analysis revealed that DEG nodes are involved in the synaptic vesicle cycle, glutamatergic synapse, PI3K-Akt signaling pathway, retrograde endocannabinoid signaling, endocrine and other factor-regulated calcium reabsorption, ribosome biogenesis in eukaryotes, and nicotine addiction. Gentamicin, isoproterenol, and tumor necrosis factor are repurposing new drugs that target CD44, which plays an important role in the development of AD. Following our model validation using the existing experimental data, our model based on previous experimental reports suggested critical molecules and candidate drugs involved in AD for further investigations in vitro and in vivo.

The cytoskeleton, composed of microtubules, intermediate filaments and actin filaments is vital for various cellular functions, particularly within the nervous system, where microtubules play a key role in intracellular transport, cell morphology, and synaptic plasticity. Tubulin-specific chaperones, including tubulin folding cofactors (TBCA, TBCB, TBCC, TBCD, TBCE), assist in the proper formation of α/β-tubulin heterodimers, essential for microtubule stability. Pathogenic variants in these chaperone-encoding genes, especially TBCD, have been linked to Progressive Encephalopathy with Brain Atrophy and Thin Corpus Callosum (PEBAT, OMIM #604,649), a severe neurodevelopmental disorder. We report three cases from two consanguineous families with varying clinical presentations of PEBAT syndrome due to homozygous pathogenic variants in the TBCD. In Family 1, two siblings (F1C1 and F1C2) harboring the homozygous c.2314C > T, p.(Arg772Cys) variant exhibited severe neurodevelopmental regression, spastic tetraplegia, seizures, and brain atrophy. In contrast, Family 2, Case 3 (F2C3), with the homozygous c.230A > G, p.(His77Arg) variant, presented a milder phenotype, including absence seizures, slight developmental delay, and less pronounced neuroanatomical abnormalities. These findings contribute to the expanding phenotypic spectrum of PEBAT and suggesting that modifier genes or epigenetic factors may influence disease severity.

Memory is a dynamic process of encoding, storing, and retrieving information. It includes sensory, short-term, and long-term memory, each with unique characteristics. Nitric oxide (NO) is a biological messenger synthesized on demand by neuronal nitric oxide synthase (nNOS) through a biochemical process initiated by glutamate binding to NMDA receptors, causing membrane depolarization and calcium influx. NO is known to regulate many signaling pathways including those related to memory consolidation. To throw light on the precise molecular mechanism of nitric oxide (NO) in memory consolidation and the possibility of targeting NO pathways as a therapeutic approach to scale down cognitive impairments. We conducted a search of the PubMed MEDLINE database, maintained by the US National Library of Medicine. The search strategy utilized Medical Subject Headings (MeSH) terms, including "nitric oxide and memory," "nitric oxide synthesis in the brain," "nitric oxide and Alzheimer's," "nitric oxide and Parkinson's," and "nitric oxide, neurodegenerative disorders, and psychiatric disorders." Additionally, relevant keywords such as "nitric oxide," "memory," and "cognitive disorders" were employed. We included the most recent preclinical and clinical studies pertinent to the review topic and limited the selection to articles published in English. NO exerts its role in memory consolidation by diffusing between neurons to promote synaptic plasticity, especially long-term potentiation (LTP). It acts as a retrograde messenger, neurotransmitter release modulator, and synaptic protein modifier. The dysregulation of NO balance in the brain can contribute to the pathogenesis of various neurodegenerative diseases, particularly Alzheimer's, Parkinson's, and psychiatric disorders. The disturbance in NO signaling is strongly correlated with synaptic signaling dysfunction and oxidative stress. NO plays a fundamental role in memory consolidation, and its dysregulation contributes to cognitive impairment-a hallmark of numerous neurodegenerative and psychiatric disorders. Future research should aim to deepen our understanding of the mechanisms underlying NO's involvement in memory consolidation and to explore therapeutic strategies targeting the NO pathway to mitigate cognitive decline in affected individuals.

Huntington's disease (HDs) is a fatal, autosomal dominant, and hereditary neurodegenerative disorder characterized by progressive motor dysfunction, cognitive decline, and psychiatric disturbances. HD is well linked to mutation in the HTT gene, which leads to an abnormal expansion of trinucleotide CAG repeats, resulting in the production of the mHTT protein and responsible for abnormally long poly-Q tract. These abnormal proteins disrupt cellular processes, including neuroinflammation, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction, ultimately leading to selective neuronal loss in the brain. Epidemiological studies reveal significant regional variability in HDs prevalence, with the highest rates observed in North America and the lowest in Africa. In addition to genetic factors, environmental influences such as exposure to metals, and chemicals, and lifestyle factors like alcohol and tobacco use may exacerbate disease progression. This review explores the molecular mechanisms underlying HDs and emphasize the role of neuroinflammatory mediators and environmental factors, in HD research. Understanding these complex interactions is crucial for developing targeted interventions that can slow or halt the progression of this devastating disease.

Neuronal Ceroid Lipofuscinosis 11 (CLN11) is an ultra-rare subtype of adult-onset Neuronal Ceroid Lipofuscinosis. Its phenotype is variable and not fully known. A 21-year-old man was evaluated in our neurogenetic outpatient clinic for early onset complex phenotype, including learning difficulties, cerebellar ataxia, cone-rod dystrophy, epilepsy, and dystonia. The patient was submitted to neurological and neuropsychological assessment, neuro-ophthalmological tests, brain MRI, EEG and whole exome sequencing. A homozygous frameshift variant (NM_002087.4: c.768_769dup; p.Gln257Profs*27) was found. Distinct type descriptions, as in this case, increase the clinical spectrum of the disease.

Intermediate CAG repeats from 29 to 33 in the ATXN2 gene contributes to the risk of amyotrophic lateral sclerosis (ALS) in European and Asian populations. In this study, 148 ALS patients of multiethnic descent: Chinese (56.1%), Malay (24.3%), Indian (12.8%), others (6.8%) and 100 neurologically normal controls were screened for the ATXN2 CAG repeat expansion. The most common repeat length in both the controls and patients was 22. No familial ALS patients were positive for the intermediate repeat sizes (29-33), while four sporadic patients (2.8%) were positive, with one harbouring a rare ATXN2 homozygous 32 repeat expansion, and a likely pathogenic variant in SPAST. All four patients had limb-onset ALS. Despite representing the smallest ethnic group in our patient cohort, three of the four patients with intermediate repeat sizes were of Indian ancestry. This study, which is the first in Malaysia and Southeast Asia, shows that ATXN2 intermediate risk expansions are relevant to ALS in these populations and will help to inform future genetic testing strategies in the clinic.

Schizophrenia (SZ) is a complex, chronic mental disorder characterized by positive symptoms (such as delusions and hallucinations), negative symptoms (including anhedonia, alogia, avolition, and social withdrawal), and cognitive deficits (affecting attention, processing speed, verbal and visuospatial learning, problem-solving, working memory, and mental flexibility). Extensive animal and clinical studies have emphasized the NMDAR hypofunction hypothesis of SZ. Glycine plays a crucial role as an agonist of NMDAR, enhancing the receptor's affinity for glutamate and supporting normal synaptic function and plasticity, that is, signal transmission between neurons. In the absence of glycine or any other co-agonists (serine and D-cycloserine), NMDAR responsiveness to glutamate decreases, reducing its likelihood to open and allow ion flow, which leads to impaired synaptic plasticity and neurotransmission. Current antipsychotic treatments are severely limited, as they only address positive symptoms, can lead to significant neurological and metabolic side effects such as sexual dysfunction, and are effective in only about half of SZ patients. Similarly, direct glycine-site modulators have shown considerable side-effects due to high-dose usage, such as nausea, nephrotoxicity, anxiety, depression, and hyperexcitability resulting from the external administration of glycine, serine, and D-cycloserine. To this effect, the current study considers glycine-like compounds with improved BBB permeability directly targeting the Glycine modulatory site (GMS). A thorough evaluation encompassing ADMET analysis, virtual screening, and molecular dynamics was used to screen the glycine-like library. Data collected revealed Compound_8, Compound_15, and Compound_945 as promising agonists. Further experimental validation is needed to confirm their preclinical relevance as SZ treatment.