RESUMO
Novel insights on regulation of gene expression mechanisms highlight the pivotal role of epitranscriptomic modifications on decision about transcript fate. These modifications include methylation of adenosine and cytosine in RNA molecules. Impairment of the normal epitranscriptome profile was observed in several pathological conditions, such as cancer and neurodegeneration. However, it is still unknown if alteration of this regulatory mechanism can be involved in cerebral cavernous malformation (CCM) development. CCM is a rare genetic condition affecting brain microvasculature, resulting from mutations in the three genes KRIT1, CCM2, and PDCD10. By data integration of association study, in silico prediction, and gene expression analysis, we evaluated role of single nucleotide polymorphisms (SNPs) highly recurrent in patients with CCM, on CCM gene expression regulation. Results showed that several of these SNPs lead to a drastic downexpression, in KRIT1 and CCM2 genes and this downregulation can be due to alteration of epitranscriptome profile, occurring these SNPs in gene regions that are subject to epitranscriptome modifications. These data suggest that this novel mechanism of gene expression regulation can be consider to further investigation on CCM pathogenesis.
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Hemangioma Cavernoso do Sistema Nervoso Central , Adenosina/genética , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Transporte/metabolismo , Citosina , Hemangioma Cavernoso do Sistema Nervoso Central/genética , Hemangioma Cavernoso do Sistema Nervoso Central/metabolismo , Humanos , Proteínas de Membrana/metabolismo , Polimorfismo de Nucleotídeo Único/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , RNA Mensageiro/genéticaRESUMO
By regulating several phases of gene expression, RNA editing modifications contribute to maintaining physiological RNA expression levels. RNA editing dysregulation can affect RNA molecule half-life, coding/noncoding RNA interaction, alternative splicing, and circular RNA biogenesis. Impaired RNA editing has been observed in several pathological conditions, including cancer and Alzheimer's disease. No data has been published yet on the editome profile of endothelial cells (ECs) isolated from human cerebral cavernous malformation (CCM) lesions. Here, we describe a landscape of editome modifications in sporadic CCM-derived ECs (CCM-ECs) by comparing editing events with those observed in human brain microvascular endothelial cells (HBMECs). With a whole transcriptome-based variant calling pipeline, we identified differential edited genes in CCM-ECs that were enriched in pathways related to angiogenesis, apoptosis and cell survival, inflammation and, in particular, to thrombin signalling mediated by protease-activated receptors and non-canonical Wnt signalling. These pathways, not yet associated to CCM development, could be a novel field for further investigations on CCM molecular mechanisms. Moreover, enrichment analysis of differentially edited miRNAs suggested additional small noncoding transcripts to consider for development of targeted therapies.
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Hemangioma Cavernoso do Sistema Nervoso Central , MicroRNAs , Células Endoteliais/metabolismo , Hemangioma Cavernoso do Sistema Nervoso Central/genética , Hemangioma Cavernoso do Sistema Nervoso Central/metabolismo , Hemangioma Cavernoso do Sistema Nervoso Central/patologia , Humanos , MicroRNAs/metabolismo , Neovascularização Patológica/genética , TranscriptomaRESUMO
Blindness due to photoreceptor degeneration is observed in both genetic and acquired eye disorders. Long blue light exposure can contribute to increase levels of oxidative compounds within the retinal pigment epithelium (RPE), enhancing risk of retinal damage. In retina, reactive oxygen species contribute to the activation of inflammatory cascade. If chronic, this inflammatory response can result in photoreceptor death. Therefore, we investigated the effects of the endogenous adduct N-retinylidene-N-retinylethanolamine (A2E) on RPE cells, in order to identify the most dysregulated cytokines and their related inflammatory pathways. RPE cells were exposed to A2E and blue light for 3h and 6h. By transcriptome analysis, we identified differentially expressed genes in A2E-treated cells, when compared to untreated ones. Expression values were quantified by the Limma R package. Enrichment analysis was performed according to the "Reactome" and the Gene Ontology databases. Expression of pro-inflammatory cytokines increased after 3h of A2E treatment and pathways related to IL-6 and IL-1 signaling resulted enriched. Also the up-regulation of genes having a protective role against inflammation was observed. Moreover, our results show that ferroptosis could contribute to RPE degeneration induced by A2E and blue light. Dysregulated genes related to retinal degeneration triggered by oxidative damage and inflammatory response activation identified in this study can be considered as potential biomarkers for targeted therapies.
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Citocinas/genética , Regulação da Expressão Gênica , Inflamação/genética , Degeneração Retiniana/genética , Epitélio Pigmentado da Retina/metabolismo , Retinoides/genética , Linhagem Celular , Sobrevivência Celular , Doença Crônica , Citocinas/biossíntese , Humanos , Inflamação/metabolismo , Inflamação/patologia , Espécies Reativas de Oxigênio/metabolismo , Degeneração Retiniana/metabolismo , Degeneração Retiniana/patologia , Epitélio Pigmentado da Retina/patologia , Pigmentos da Retina , Retinoides/biossíntese , Transdução de SinaisRESUMO
WHAT IS KNOWN AND OBJECTIVE: Trimethylaminuria is a metabolic disorder characterized by excessive excretion of trimethylamine in body fluids following FMO3 gene mutations. Secondary forms of the disease may be due to consumption of trimethylamine precursor-rich foods or metabolism of some xenobiotics. CASE SUMMARY: A HIV patient developed secondary trimethylaminuria following antiretroviral treatment. Riboflavin supplementation ameliorated his phenotype. 1 H-NMR confirmed increased urine level of TMA. Several genes involved in choline catabolism harboured missense mutations. Riboflavin supplement improved enzymatic activity of mutated enzymes promoting TMA clearance. WHAT IS NEW AND CONCLUSION: Antiretrovirals may increase the concentration of TMA precursors. The present study reports antiretroviral treatment as risk factor for such secondary trimethylaminuria. Riboflavin is an effective treatment.
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Antirretrovirais/efeitos adversos , Infecções por HIV/tratamento farmacológico , Erros Inatos do Metabolismo/induzido quimicamente , Metilaminas/urina , Adulto , Antirretrovirais/uso terapêutico , Humanos , Imageamento por Ressonância Magnética , Masculino , Erros Inatos do Metabolismo/tratamento farmacológico , Riboflavina/uso terapêuticoRESUMO
BACKGROUND: Retinitis pigmentosa punctata albescens (RPA) is a particular form of retinitis pigmentosa characterized by childhood onset night blindness and areas of peripheral retinal atrophy. We investigated the genetic cause of RPA in a family consisting of two affected Egyptian brothers with healthy consanguineous parents. METHODS: Mutational analysis of four RPA causative genes was realized by Sanger sequencing on both probands, and detected variants were subsequently genotyped in their parents. Afterwards, found variants were deeply, statistically, and in silico characterized to determine their possible effects and association with RPA. RESULTS: Both brothers carry three missense PRPH2 variants in a homozygous condition (c.910C > A, c.929G > A, and c.1013A > C) and two promoter variants in RHO (c.-26A > G) and RLBP1 (c.-70G > A) genes, respectively. Haplotype analyses highlighted a PRPH2 rare haplotype variant (GAG), determining a possible alteration of PRPH2 binding with melanoregulin and other outer segment proteins, followed by photoreceptor outer segment instability. Furthermore, an altered balance of transcription factor binding sites, due to the presence of RHO and RLBP1 promoter variants, might determine a comprehensive downregulation of both genes, possibly altering the PRPH2 shared visual-related pathway. CONCLUSIONS: Despite several limitations, the study might be a relevant step towards detection of novel scenarios in RPA etiopathogenesis.
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Variação Genética , Haplótipos , Periferinas/genética , Segmento Externo das Células Fotorreceptoras da Retina/metabolismo , Retinose Pigmentar/metabolismo , Sítios de Ligação , Proteínas de Transporte/genética , Pré-Escolar , Simulação por Computador , Análise Mutacional de DNA , Egito , Saúde da Família , Humanos , Transdução de Sinal Luminoso , Masculino , Mutação , Mutação de Sentido Incorreto , Doenças do Sistema Nervoso Periférico/metabolismo , Dobramento de Proteína , Degeneração Retiniana/metabolismo , Proteínas rho de Ligação ao GTP/genéticaRESUMO
BACKGROUND: Trimethylaminuria (TMAU) is a rare genetic disease characterized by the accumulation of trimethylamine (TMA) and its subsequent excretion trough main body fluids, determining the characteristic fish odour in affected patients. We realized an experimental study to investigate the role of several coding variants in the causative gene FMO3, that were only considered as polymorphic or benign, even if the available literature on them did not functionally explain their ineffectiveness on the encoded enzyme. METHODS: Mutational analysis of 26 TMAU patients was realized by Sanger sequencing. Detected variants were, subsequently, deeply statistically and in silico characterized to determine their possible effects on the enzyme activity. To achieve this goal, a docking prediction for TMA/FMO3 and an unbinding pathway study were performed. Finally, a TMAO/TMA urine quantification by 1H-NMR spectroscopy was performed to support modelling results. RESULTS: The FMO3 screening of all patients highlighted the presence of 17 variants distributed in 26 different haplotypes. Both non-sense and missense considered variants might impair the enzymatic kinetics of FMO3, probably reducing the interaction time between the protein catalytic site and TMA, or losing the wild-type binding site. CONCLUSIONS: Even if further functional assays will confirm our predictive results, considering the possible role of FMO3 variants with still uncertain effects, might be a relevant step towards the detection of novel scenarios in TMAU etiopathogenesis.
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Erros Inatos do Metabolismo , Metilaminas/urina , Modelos Moleculares , Mutação , Oxigenases , Adulto , Feminino , Humanos , Masculino , Erros Inatos do Metabolismo/enzimologia , Erros Inatos do Metabolismo/genética , Erros Inatos do Metabolismo/urina , Ressonância Magnética Nuclear Biomolecular , Oxigenases/química , Oxigenases/genética , Oxigenases/metabolismoRESUMO
Brain arteriovenous malformation (bAVM) is a congenital defect affecting brain microvasculature, characterized by a direct shunt from arterioles to venules. Germline mutations in several genes related to transforming growth factor beta (TGF-ß)/BMP signaling are linked to both sporadic and hereditary phenotypes. However, the low incidence of inherited cases makes the genetic bases of the disease unclear. To increase this knowledge, we performed a whole exome sequencing on five patients, on DNA purified by peripheral blood. Variants were filtered based on frequency and functional class. Those selected were validated by Sanger sequencing. Genes carrying selected variants were prioritized to relate these genes with those already known to be linked to bAVM development. Most of the prioritized genes showed a correlation with the TGF-ßNotch signaling and vessel morphogenesis. However, two novel pathways related to cilia morphogenesis and ion homeostasis were enriched in mutated genes. These results suggest novel insights on sporadic bAVM onset and confirm its genetic heterogeneity. The high frequency of germline variants in genes related to TGF-ß signaling allows us to hypothesize bAVM as a complex trait resulting from the co-existence of low-penetrance loci. Deeper knowledge on bAVM genetics can improve personalized diagnosis and can be helpful with genotype-phenotype correlations.
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Células Endoteliais/metabolismo , Mutação em Linhagem Germinativa , Homeostase , Malformações Arteriovenosas Intracranianas/diagnóstico , Malformações Arteriovenosas Intracranianas/genética , Transdução de Sinais , Biologia Computacional/métodos , Ontologia Genética , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Reprodutibilidade dos Testes , Análise de Sequência de DNA , Sequenciamento do ExomaRESUMO
Ion channels are membrane-spanning integral proteins expressed in multiple organs, including the eye. Here, ion channels play a role in several physiological processes, like signal transmission and visual processing. A wide range of mutations have been reported in the corresponding genes and their interacting subunit coding genes, which contribute significantly to a wide spectrum of ocular diseases collectively called channelopathies, a subgroup of inherited retinal dystrophies. Such mutations result in either a loss or gain-of channel functions affecting the structure, assembly, trafficking and localization of channel proteins. We investigated the probands of seven Italian and Egyptian families affected by not completely defined forms of inherited retinal dystrophies, by whole exome sequencing (WES) experiments, and found interesting variants in already known causative genes probably able to impair retinal functionalities. However, because such variants did not completely explain the phenotype manifested by each patient, we proceed to further investigate possible related genes carrying mutations that might complement previously found data, based on the common aspect linked to neurotransmission impairments. We found 10 mutated genes whose variants might alter important ligand binding sites differently distributed through all considered patients. Such genes encode for ion channels, or their regulatory proteins, and strictly interact with known causative genes, also sharing with them synaptic-related pathways. Taking into account several limitations that will be resolved by further experiments, we believe that our exploratory investigation will help scientists to provide a new promising paradigm for precise diagnosis of retinal dystrophies to facilitate the development of rational treatments.
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Genes Modificadores , Canais Iônicos/genética , Fenótipo , Distrofias Retinianas/genética , Exoma , Feminino , Humanos , Masculino , Linhagem , Polimorfismo Genético , Sinapses/genéticaRESUMO
Cerebrovascular malformations include a wide range of blood vessel disorders affecting brain vasculature. Neuroimaging differential diagnosis can result unspecific due to similar phenotypes of lesions and their deep localization. Next-generation sequencing (NGS) platforms simultaneously analyze several hundreds of genes and can be applied for molecular distinction of different phenotypes within the same disorder's macro-area. We discuss about the main criticisms regarding molecular bases of cerebral cavernous malformations (CCM) and brain arteriovenous malformations (AVM), highlighting both common pathogenic aspects and genetic differences leading to lesion development. Many recent studies performed on human CCM and AVM tissues aim to detect genetic markers to better understand molecular bases and pathogenic mechanism, particularly for sporadic cases. Several genes involved in angiogenesis show different expression patterns between CCM and AVM, and these could represent a valid starting point to project a NGS panel to apply for differential cerebrovascular malformation diagnosis.
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Neoplasias do Sistema Nervoso Central/genética , Hemangioma Cavernoso do Sistema Nervoso Central/genética , Malformações Arteriovenosas Intracranianas/genética , Animais , Neoplasias do Sistema Nervoso Central/diagnóstico , Hemangioma Cavernoso do Sistema Nervoso Central/diagnóstico , Humanos , Malformações Arteriovenosas Intracranianas/diagnósticoRESUMO
BACKGROUND: Autosomal recessive forms of retinitis punctata albescens (RPA) have been described. RPA is characterized by progressive retinal degeneration due to alteration in visual cycle and consequent deposit of photopigments in retinal pigment epithelium. Five loci have been linked to RPA onset. Among these, the retinaldehyde-binding protein 1 gene, RLBP1, is the most frequently involved and several founder mutations were reported. We report results of a genetic molecular investigation performed on a large Sicilian family in which appears a young woman with RPA. RESULTS: The proband is in homozygous condition for a novel RLBP1 single-pair deletion, and her healthy parents, both heterozygous, are not consanguineous. Thenovelc.398delC (p.P133Qfs*258) involves the exon 6 and leads to a premature stop codon, resulting in a truncated protein entirely missing of CRAL-TRIO lipid-binding domain. Pedigree analysis showed other non-consanguineous relatives heterozygous for the same mutation in the family. Extension of mutation research in the native town of the proband revealed its presence also in healthy subjects, in a heterozygous condition. CONCLUSIONS: A novel RLBP1 truncating mutation was detected in a young girl affected by RPA. Although her parents are not consanguineous, the mutation was observed in a homozygous condition. Being them native of the same small Sicilian town of Fiumedinisi, the hypothesis of a geographical area-related mutation was assessed and confirmed.
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Proteínas de Transporte/genética , Mutação , Doenças Retinianas/genética , Adulto , Sequência de Bases , Proteínas de Transporte/química , Análise Mutacional de DNA , Feminino , Geografia , Heterozigoto , Homozigoto , Humanos , Masculino , Linhagem , Conformação ProteicaRESUMO
Glyoxalase 1 (GLO1) is a ubiquitous cellular enzyme involved in detoxification of methylglyoxal (MGO), a cytotoxic byproduct of glycolysis, whose excess can cause oxidative stress. In retinitis pigmentosa (RP), the prevalent cause of blindness just during working life in the industrialized countries, oxidative stress represents one of the possible mechanisms leading to death of cones following that of rods in the retina. To date, the causes of secondary death of cones remain unclear and among proposed mechanisms are: the deprivation of trophic factors normally produced by healthy rods, a compromised uptake of nutrients to cones due to irreversible destruction of RPE-cone outer segment, microglial activation and following release of pro-inflammatory cytokines and rod-derived toxins. In present paper, role of oxidative stress due to an excess of MGO was evaluated. In particular, we wanted to determine whether single nucleotide polymorphisms (SNPs) in GLO1 influence enzyme activity, contributing to cone death in advanced RP. 120 healthy controls and 80 RP patients from Sicilian population were genotyped for three GLO1 common SNPs, rs1130534 (c.372A>T, p.G124G), rs2736654 (c.A332C, p.E111A) and rs1049346 (c.-7C>T, 5'-UTR). While c.A332C polymorphism was not associated with RP, c.372A>T showed an allelic association (T372 allele frequency = 70% vs 60% in controls, p = 0.0071). Conversely, c.-7C>T showed both genotypic (χ2 = 68.0952; p = 1.634e-15) and allelic associations (χ2 = 51.7094; p = 6.435e-13): mutated allele frequency was higher in controls than in patients, suggesting its possible protective role. RP susceptibility may be associated with two of the analyzed GLO1 polymorphisms (rs1130534 and rs1049346).
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Lactoilglutationa Liase/genética , Retinose Pigmentar/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Humanos , Lactoilglutationa Liase/metabolismo , Masculino , Pessoa de Meia-Idade , Estresse Oxidativo/genética , Polimorfismo de Nucleotídeo Único , Aldeído Pirúvico/metabolismo , Retina/metabolismo , Células Fotorreceptoras Retinianas Cones/metabolismo , Retinose Pigmentar/metabolismo , SicíliaRESUMO
BACKGROUND: Cerebral cavernous malformations (CCMs) are vascular anomalies of the nervous system mostly located in the brain presenting sporadically or familial. Causes of familial forms are mutations in CCM1 (Krit1), CCM2 (MGC4607) and CCM3 (PDCD10) genes. Sporadic forms with no affected relative most often have only one lesion and no germ line mutations. However, a number of sporadic cases with multiple lesions have been reported and are indeed genetic cases with a de novo mutation or a mutation inherited from an asymptomatic parent. METHODS: Here, we performed an analysis of regulatory region of CCM genes in 60 sporadic patients, negative for mutations in coding region and intron-exon boundaries and large deletion/duplications in CCM genes by direct sequencing and MLPA. Among 5 variants identified in 851-bp region shared by CCM3 and SERPINI1 genes and acting as asymmetric bidirectional promoter, two polymorphisms c.-639 T > C/rs9853967 and c.-591 T > C/rs11714980 were selected. A case-control study was performed to analyze their possible relationships with sporadic CCMs. Promoter haplotypes activities on CCM3/SERPINI1 genes expression were tested by dual-luciferase assay. RESULTS: No variants were identified in CCM1 and CCM2 regulatory regions. In CCM3/SERPINI1 asymmetric bidirectional promoter 5 variants, 2 of them unknown and 3 corresponding to polymorphisms c.-639 T > C/rs9853967, c.-591 T > C/rs11714980 and c.-359G > A/rs9834676 were detected. While rs9853967 and rs11714980 polymorphisms fall in a critical regulatory fragment outside the minimal promoter in intergenic region, other variants had no effects on transcription factor binding according to RegRNA tool. Case-control study performed on 60 patients and 350 healthy controls showed frequencies of the mutated alleles significantly higher in the control group than in patients. Furthermore, the functional assay showed a significant reduction of CCM3 expression for C-C haplotype even more than for T-C and C-T haplotypes. In SERPINI1 direction, the reduction was not statistically significant. CONCLUSIONS: Our data indicated that rs9853967 and rs11714980 polymorphisms could be associated with a protective role in CCM disease.
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Proteínas Reguladoras de Apoptose/genética , Hemangioma Cavernoso do Sistema Nervoso Central/genética , Proteínas de Membrana/genética , Neuropeptídeos/genética , Polimorfismo de Nucleotídeo Único , Proteínas Proto-Oncogênicas/genética , Serpinas/genética , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Regiões Promotoras Genéticas , Adulto Jovem , NeuroserpinaRESUMO
OBJECTIVES: To assess effectiveness of an experimental sterilization method based on the exposure of an O3/O2 gas mixture directly inside the packaging for clear aligners. MATERIALS AND METHODS: Fifty samples consisting of pieces of polyethylene terephthalate glycol (PET-G) aligners were contaminated by manual handling and subsequently divided into different groups (n = 30 for exposure to O3/O2 gas at different times, n = 10 for positive control with 2% chlorhexidine digluconate, n = 10 for negative control). The measurement of optical densities (OD) of the initial and final microbial cultures was recorded for all groups. Kruskal-Wallis test was used for differences between groups while Wilcoxon test was used to compare initial and final OD values within groups. Statistical significance was set at P < .05. RESULTS: Comparison within the groups showed statistically significant differences for exposure to the gaseous mixture (72 hours), for positive and negative controls. Other significant differences were found in the multiple comparisons between the application of gaseous ozone (48 hours and 72 hours) and the negative control. CONCLUSIONS: The direct exposure of gaseous ozone on the aligners inside their packaging showed microbicidal capacity at 72 hours, which was equivalent to the positive control with immersion in chlorhexidine digluconate. This innovative sterilization procedure could be considered in the final manufacturing processes of clear aligners to eliminate the potentially pathogenic microorganisms that are deposited on surfaces of these orthodontic devices.
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Clorexidina/análogos & derivados , Aparelhos Ortodônticos Removíveis , Ozônio , Clorexidina/farmacologia , EsterilizaçãoRESUMO
Beyond their crucial role in energy production, mitochondria harbor a distinct genome subject to epigenetic regulation akin to that of nuclear DNA. This paper delves into the nascent but rapidly evolving fields of mitoepigenetics and mitoepigenomics, exploring the sophisticated regulatory mechanisms governing mitochondrial DNA (mtDNA). These mechanisms encompass mtDNA methylation, the influence of non-coding RNAs (ncRNAs), and post-translational modifications of mitochondrial proteins. Together, these epigenetic modifications meticulously coordinate mitochondrial gene transcription, replication, and metabolism, thereby calibrating mitochondrial function in response to the dynamic interplay of intracellular needs and environmental stimuli. Notably, the dysregulation of mitoepigenetic pathways is increasingly implicated in mitochondrial dysfunction and a spectrum of human pathologies, including neurodegenerative diseases, cancer, metabolic disorders, and cardiovascular conditions. This comprehensive review synthesizes the current state of knowledge, emphasizing recent breakthroughs and innovations in the field. It discusses the potential of high-resolution mitochondrial epigenome mapping, the diagnostic and prognostic utility of blood or tissue mtDNA epigenetic markers, and the promising horizon of mitochondrial epigenetic drugs. Furthermore, it explores the transformative potential of mitoepigenetics and mitoepigenomics in precision medicine. Exploiting a theragnostic approach to maintaining mitochondrial allostasis, this paper underscores the pivotal role of mitochondrial epigenetics in charting new frontiers in medical science.
Assuntos
Metilação de DNA , DNA Mitocondrial , Epigênese Genética , Mitocôndrias , Humanos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitocôndrias/patologia , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Processamento de Proteína Pós-Traducional/genética , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Doenças Mitocondriais/genética , Doenças Mitocondriais/metabolismo , Doenças Mitocondriais/patologia , RNA não Traduzido/genética , RNA não Traduzido/metabolismo , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologiaRESUMO
Aims: This pilot study investigates the potential pathogenic role of G-quadruplex (G4) structures in RPGR-associated retinal degeneration, starting from a case of suspected X-linked form affected family. We hypothesize that the stabilization of these structures might alter DNA replication and transcription, inducing genetic instability and influencing gene expression. Main methods: We conducted whole genome amplification experiments and next-generation sequencing to detect the blockade of polymerase activity by G4 structures. Our specific focus was the RPGR gene, which hosts a high concentration of predicted G4-forming motifs and is implicated in most X-linked retinal degeneration cases. To understand the potential interference of G4 structures, we applied computational and 3D molecular modeling to visualize interferences in DNA replication and transcription regulation. Key findings: Our data confirmed the obstruction of DNA polymerase enzymes by G4 structures, particularly when stabilized by the compound pyridostatin. This obstruction was evident in the reduced amplification of RPGR gene regions and a shift in the start/end sites of putative G4 motifs. Moreover, the modeling indicated a potential disruption of critical promoter elements and RNA polymerase binding, which could drastically alter gene expression. Significance: Our findings suggest that G4 formation in the RPGR gene could lead to genetic instability and affect the expression of RPGR, contributing to retinal dystrophy. Moreover, this study underscores the broader implications of G4 structures in other genetic disorders. Improved understanding of G4 structures could reveal novel therapeutic targets to combat genetic disorders, promoting the advancement of personalized medicine and precision health.
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Aims: Maternally inherited diabetes and deafness (MIDD) is a complex disorder characterized by multiorgan clinical manifestations, including diabetes, hearing loss, and ophthalmic complications. This pilot study aimed to elucidate the intricate interplay between nuclear and mitochondrial genetics, epigenetic modifications, and their potential implications in the pathogenesis of MIDD. Main methods: A comprehensive genomic approach was employed to analyze a Sicilian family affected by clinically characterized MIDD, negative to the only known causative m.3243 A > G variant, integrating whole-exome sequencing and whole-genome bisulfite sequencing of both nuclear and mitochondrial analyses. Key findings: Rare and deleterious variants were identified across multiple nuclear genes involved in retinal homeostasis, mitochondrial function, and epigenetic regulation, while complementary mitochondrial DNA analysis revealed a rich tapestry of genetic diversity across genes encoding components of the electron transport chain and ATP synthesis machinery. Epigenetic analyses uncovered significant differentially methylated regions across the genome and within the mitochondrial genome, suggesting a nuanced landscape of epigenetic modulation. Significance: The integration of genetic and epigenetic data highlighted the potential crosstalk between nuclear and mitochondrial regulation, with specific mtDNA variants influencing methylation patterns and potentially impacting the expression and regulation of mitochondrial genes. This pilot study provides valuable insights into the complex molecular mechanisms underlying MIDD, emphasizing the interplay between nucleus and mitochondrion, tracing the way for future research into targeted therapeutic interventions and personalized approaches for disease management.
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Arteriovenous malformation of the brain (bAVM) is a vascular phenotype related to brain defective angiogenesis. Involved vessels show impaired expression of vascular differentiation markers resulting in the arteriolar to venule direct shunt. In order to clarify aberrant gene expression occurring in bAVM, here we describe results obtained by methylome analysis performed on endothelial cells (ECs) isolated from bAVM specimens, compared to human cerebral microvascular ECs. Results were validated by quantitative methylation-specific PCR and quantitative realtime-PCR. Differential methylation events occur in genes already linked to bAVM onset, as RBPJ and KRAS. However, among differentially methylated genes, we identified EPHB1 and several other loci involved in EC adhesion as well as in EC/vascular smooth muscle cell (VSMC) crosstalk, suggesting that only endothelial dysfunction might not be sufficient to trigger the bAVM phenotype. Moreover, aberrant methylation pattern was reported for many lncRNA genes targeting transcription factors expressed during neurovascular development. Among these, the YBX1 that was recently shown to target the arteridin coding gene. Finally, in addition to the conventional CpG methylation, we further considered the role of impaired CHG methylation, mainly occurring in brain at embryo stage. We showed as differentially CHG methylated genes are clustered in pathways related to EC homeostasis, as well as to VSMC-EC crosstalk, suggesting as impairment of this interaction plays a prominent role in loss of vascular differentiation, in bAVM phenotype.
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Alzheimer-Perusini's (AD) disease represents the most spread dementia around the world and constitutes a serious problem for public health. It was first described by the two physicians from whom it took its name. Nowadays, we have extensively expanded our knowledge about this disease. Starting from a merely clinical and histopathologic description, we have now reached better molecular comprehension. For instance, we passed from an old conceptualization of the disease based on plaques and tangles to a more modern vision of mixed proteinopathy in a one-to-one relationship with an alteration of specific glial and neuronal phenotypes. However, no disease-modifying therapies are yet available. It is likely that the only way to find a few "magic bullets" is to deepen this aspect more and more until we are able to draw up specific molecular profiles for single AD cases. This review reports the most recent classifications of AD atypical variants in order to summarize all the clinical evidence using several discrimina (for example, post mortem neurofibrillary tangle density, cerebral atrophy, or FDG-PET studies). The better defined four atypical forms are posterior cortical atrophy (PCA), logopenic variant of primary progressive aphasia (LvPPA), behavioral/dysexecutive variant and AD with corticobasal degeneration (CBS). Moreover, we discuss the usefulness of such classifications before outlining the molecular-genetic aspects focusing on microglial activity or, more generally, immune system control of neuroinflammation and neurodegeneration.
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In the early stages of Alzheimer-Perusini's disease (AD), individuals often experience vision-related issues such as color vision impairment, reduced contrast sensitivity, and visual acuity problems. As the disease progresses, there is a connection with glaucoma and age-related macular degeneration (AMD) leading to retinal cell death. The retina's involvement suggests a link with the hippocampus, where most AD forms start. A thinning of the retinal nerve fiber layer (RNFL) due to the loss of retinal ganglion cells (RGCs) is seen as a potential AD diagnostic marker using electroretinography (ERG) and optical coherence tomography (OCT). Amyloid beta fragments (Aß), found in the eye's vitreous and aqueous humor, are also present in the cerebrospinal fluid (CSF) and accumulate in the retina. Aß is known to cause tau hyperphosphorylation, leading to its buildup in various retinal layers. However, diseases like AD are now seen as mixed proteinopathies, with deposits of the prion protein (PrP) and α-synuclein found in affected brains and retinas. Glial cells, especially microglial cells, play a crucial role in these diseases, maintaining immunoproteostasis. Studies have shown similarities between retinal and brain microglia in terms of transcription factor expression and morphotypes. All these findings constitute a good start to achieving better comprehension of neurodegeneration in both the eye and the brain. New insights will be able to bring the scientific community closer to specific disease-modifying therapies.