RESUMO
Tumor heterogeneity refers to the diversity observed among tumor cells: both between different tumors (inter-tumor heterogeneity) and within a single tumor (intra-tumor heterogeneity). These cells can display distinct morphological and phenotypic characteristics, including variations in cellular morphology, metastatic potential and variability treatment responses among patients. Therefore, a comprehensive understanding of such heterogeneity is necessary for deciphering tumor-specific mechanisms that may be diagnostically and therapeutically valuable. Innovative and multidisciplinary approaches are needed to understand this complex feature. In this context, proteogenomics has been emerging as a significant resource for integrating omics fields such as genomics and proteomics. By combining data obtained from both Next-Generation Sequencing (NGS) technologies and mass spectrometry (MS) analyses, proteogenomics aims to provide a comprehensive view of tumor heterogeneity. This approach reveals molecular alterations and phenotypic features related to tumor subtypes, potentially identifying therapeutic biomarkers. Many achievements have been made; however, despite continuous advances in proteogenomics-based methodologies, several challenges remain: in particular the limitations in sensitivity and specificity and the lack of optimal study models. This review highlights the impact of proteogenomics on characterizing tumor phenotypes, focusing on the critical challenges and current limitations of its use in different clinical and preclinical models for tumor phenotypic characterization.
Assuntos
Neoplasias , Fenótipo , Proteogenômica , Humanos , Proteogenômica/métodos , Neoplasias/genética , Neoplasias/patologia , Neoplasias/metabolismo , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Animais , Sequenciamento de Nucleotídeos em Larga Escala , Heterogeneidade Genética , Espectrometria de Massas/métodos , Proteômica/métodosRESUMO
The bee gut microbiota plays an important role in the services the bees pay to the environment, humans and animals. Alongside, gut-associated microorganisms are vehiculated between apparently remote habitats, promoting microbial heterogeneity of the visited microcosms and the transfer of the microbial genetic elements. To date, no metaproteomics studies dealing with the functional bee microbiota are available. Here, we employ a metaproteomics approach to explore a fraction of the bacterial, fungal, and unicellular parasites inhabiting the bee gut. The bacterial community portrays a dynamic composition, accounting for specimens of human and animal concern. Their functional features highlight the vehiculation of virulence and antimicrobial resistance traits. The fungal and unicellular parasite fractions include environment- and animal-related specimens, whose metabolic activities support the spatial spreading of functional features. Host proteome depicts the major bee physiological activities, supporting the metaproteomics strategy for the simultaneous study of multiple microbial specimens and their host-crosstalks. Altogether, the present study provides a better definition of the structure and function of the bee gut microbiota, highlighting its impact in a variety of strategies aimed at improving/overcoming several current hot topic issues such as antimicrobial resistance, environmental pollution and the promotion of environmental health.
Assuntos
Anti-Infecciosos , Microbioma Gastrointestinal , Microbiota , Saúde Única , Humanos , Abelhas , Animais , Reações CruzadasRESUMO
Goat cheese is an important element of the Mediterranean diet, appreciated for its health-promoting features and unique taste. A pivotal role in the development of these characteristics is attributed to the microbiota and its continuous remodeling over space and time. Nevertheless, no thorough study of the cheese-associated microbiota using two metaomics approaches has previously been conducted. Here, we employed 16S rRNA gene sequencing and metaproteomics to explore the microbiota of a typical raw goat milk cheese at various ripening timepoints and depths of the cheese wheel. The 16S rRNA gene-sequencing and metaproteomics results described a stable microbiota ecology across the selected ripening timepoints, providing evidence for the microbiologically driven fermentation of goat milk products. The important features of the microbiota harbored on the surface and in the core of the cheese mass were highlighted in both compositional and functional terms. We observed the rind microbiota struggling to maintain the biosafety of the cheese through competition mechanisms and/or by preventing the colonization of the cheese by pathobionts of animal or environmental origin. The core microbiota was focused on other biochemical processes, supporting its role in the development of both the health benefits and the pleasant gustatory nuances of goat cheese.
Assuntos
Queijo , Microbiota , Saúde Única , Animais , Queijo/análise , Cabras/genética , RNA Ribossômico 16S/genética , Bactérias/genética , Microbiota/genéticaRESUMO
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive degeneration of the corticospinal motor neurons, which ultimately leads to death. The repeat expansion in chromosome 9 open reading frame 72 (C9ORF72) represents the most common genetic cause of ALS and it is also involved in the pathogenesis of other neurodegenerative disorders. To offer insights into C9ORF72-mediated pathogenesis, we quantitatively analyzed the proteome of patient-derived primary skin fibroblasts from ALS patients carrying the C9ORF72 mutation compared with ALS patients who tested negative for it. Differentially expressed proteins were identified, used to generate a protein-protein interaction network and subjected to a functional enrichment analysis to unveil altered molecular pathways. ALS patients were also compared with patients affected by frontotemporal dementia carrying the C9ORF72 repeat expansion. As a result, we demonstrated that the molecular pathways mainly altered in fibroblasts (e.g., protein homeostasis) mirror the alterations observed in C9ORF72-mutated neurons. Moreover, we highlighted novel molecular pathways (nuclear and mitochondrial transports, vesicle trafficking, mitochondrial bioenergetics, glucose metabolism, ER-phagosome crosstalk and Slit/Robo signaling pathway) which might be further investigated as C9ORF72-specific pathogenetic mechanisms. Data are available via ProteomeXchange with the identifier PXD023866.
Assuntos
Esclerose Lateral Amiotrófica , Proteína C9orf72 , Expansão das Repetições de DNA , Fibroblastos , Proteoma , Transdução de Sinais/genética , Pele , Adulto , Idoso , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Proteína C9orf72/genética , Proteína C9orf72/metabolismo , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Proteoma/genética , Proteoma/metabolismo , Pele/metabolismo , Pele/patologiaRESUMO
More than 300 different protein post-translational modifications are currently known, but only a few have been extensively investigated because modified proteoforms are commonly present in sub-stoichiometry amount. For this reason, improvement of specific enrichment techniques is particularly useful for the proteomic characterization of post-translationally modified proteins. Enrichment proteomic strategies could help the researcher in the challenging issue to decipher the complex molecular cross-talk existing between the different factors influencing the cellular pathways. In this review the state of art of the platforms applied for the enrichment of specific and most common post-translational modifications, such as glycosylation and glycation, phosphorylation, sulfation, redox modifications (i.e. sulfydration and nitrosylation), methylation, acetylation, and ubiquitinylation, are described. Enrichments strategies applied to characterize less studied post-translational modifications are also briefly discussed.
Assuntos
Processamento de Proteína Pós-Traducional , Proteínas/metabolismo , Proteômica , Glicosilação , Humanos , OxirreduçãoRESUMO
Recent advances in the field of meta-omics sciences and related bioinformatics tools have allowed a comprehensive investigation of human-associated microbiota and its contribution to achieving and maintaining the homeostatic balance. Bioactive compounds from the microbial community harboring the human gut are involved in a finely tuned network of interconnections with the host, orchestrating a wide variety of physiological processes. These includes the bi-directional crosstalk between the central nervous system, the enteric nervous system, and the gastrointestinal tract (i.e., gut-brain axis). The increasing accumulation of evidence suggest a pivotal role of the composition and activity of the gut microbiota in neurodegeneration. In the present review we aim to provide an overview of the state-of-the-art of meta-omics sciences including metagenomics for the study of microbial genomes and taxa strains, metatranscriptomics for gene expression, metaproteomics and metabolomics to identify and/or quantify microbial proteins and metabolites, respectively. The potential and limitations of each discipline were highlighted, as well as the advantages of an integrated approach (multi-omics) to predict microbial functions and molecular mechanisms related to human diseases. Particular emphasis is given to the latest results obtained with these approaches in an attempt to elucidate the link between the gut microbiota and the most common neurodegenerative diseases, such as multiple sclerosis (MS), Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS).
Assuntos
Encéfalo/fisiologia , Suscetibilidade a Doenças , Retroalimentação Fisiológica , Trato Gastrointestinal/fisiologia , Doenças Neurodegenerativas/etiologia , Doenças Neurodegenerativas/metabolismo , Animais , Genômica/métodos , Humanos , Metabolômica/métodos , Metagenômica/métodos , Microbiota , Proteômica/métodosRESUMO
Proteins oxidation by reactive species is implicated in the aetiology or progression of a panoply of disorders and diseases such as neurodegenerative disorders. It is becoming increasingly evident that redox imbalance in the brain mediates neurodegeneration. Free radicals, as reactive species of oxygen (ROS) but also reactive nitrogen species (RNS) and reactive sulfur species (RSS), are generated in vivo from several sources. Within the cell the mitochondria represent the main source of ROS and mitochondrial dysfunction is both the major contributor to oxidative stress (OS) as well its major consequence.To date there are no doubts that a condition of OS added to other factors as mitochondrial damage in mtDNA or mitochondrial respiratory chain, may contribute to trigger or amplify mechanisms leading to neurodegenerative disorders.In this chapter, we aim at illustrate the molecular interplay occurring between mitochondria and OS focusing on Amyotrophic Lateral Sclerosis, describing a phenotypic reprogramming mechanism of mitochondria in complex neurological disorder.
Assuntos
Esclerose Lateral Amiotrófica , Mitocôndrias , Estresse Oxidativo , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/fisiopatologia , DNA Mitocondrial/genética , Humanos , Mitocôndrias/patologia , Espécies Reativas de Nitrogênio , Espécies Reativas de Oxigênio/metabolismoRESUMO
A number of factors can trigger amyotrophic lateral sclerosis (ALS), although its precise pathogenesis is still uncertain. In a previous study done by us, poisonous liquoral levels of hydrogen sulphide (H2S) in sporadic ALS patients were reported. In the same study very high concentrations of H2S in the cerebral tissues of the familial ALS (fALS) model of the SOD1G93A mouse, were measured. The objective of this study was to test whether decreasing the levels of H2S in the fALS mouse could be beneficial. Amino-oxyacetic acid (AOA)-a systemic dual inhibitor of cystathionine-ß-synthase and cystathionine-γ lyase (two key enzymes in the production of H2S)-was administered to fALS mice. AOA treatment decreased the content of H2S in the cerebral tissues, and the lifespan of female mice increased by approximately ten days, while disease progression in male mice was not affected. The histological evaluation of the spinal cord of the females revealed a significant increase in GFAP positivity and a significant decrease in IBA1 positivity. In conclusion, the results of the study indicate that, in the animal model, the inhibition of H2S production is more effective in females. The findings reinforce the need to adequately consider sex as a relevant factor in ALS.
Assuntos
Ácido Amino-Oxiacético/farmacologia , Esclerose Lateral Amiotrófica/metabolismo , Cistationina beta-Sintase/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Sulfeto de Hidrogênio/metabolismo , Ácido Amino-Oxiacético/uso terapêutico , Esclerose Lateral Amiotrófica/tratamento farmacológico , Esclerose Lateral Amiotrófica/genética , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Células Cultivadas , Inibidores Enzimáticos/uso terapêutico , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neuroglia/efeitos dos fármacos , Fatores Sexuais , Superóxido Dismutase-1/genéticaRESUMO
Mitochondria are undeniably the cell powerhouse, directly affecting cell survival and fate. Growing evidence suggest that mitochondrial protein repertoire affects metabolic activity and plays an important role in determining cell proliferation/differentiation or quiescence shift. Consequently, the bioenergetic status of a cell is associated with the quality and abundance of the mitochondrial populations and proteomes. Mitochondrial morphology changes in the development of different cellular functions associated with metabolic switches. It is therefore reasonable to speculate that different cell lines do contain different mitochondrial-associated proteins, and the investigation of these pools may well represent a source for mining missing proteins (MPs). A very effective approach to increase the number of IDs through mass spectrometry consists of reducing the complexity of the biological samples by fractionation. The present study aims at investigating the mitochondrial proteome of five phenotypically different cell lines, possibly expressing some of the MPs, through an enrichment-fractionation approach at the organelle and protein level. We demonstrate a substantial increase in the proteome coverage, which, in turn, increases the likelihood of detecting low abundant proteins, often falling in the category of MPs, and resulting, for the present study, in the identification of METTL12, FAM163A, and RGS13. All MS data have been deposited to the MassIVE data repository ( https://massive.ucsd.edu ) with the data set identifier MSV000082409 and PXD010446.
Assuntos
Mitocôndrias/química , Proteínas Mitocondriais/análise , Proteoma/análise , Linhagem Celular , Fracionamento Químico , Bases de Dados de Proteínas , Humanos , Espectrometria de Massas/métodos , Proteínas de Membrana/análise , Metiltransferases/análise , Proteínas de Neoplasias/análise , Proteômica/métodos , Proteínas RGS/análiseRESUMO
INTRODUCTION: The development of precision medicine requires advanced technologies to address the multifactorial disease stratification and to support personalized treatments. Among omics techniques, proteomics based on Mass Spectrometry (MS) is becoming increasingly relevant in clinical practice allowing a phenotypic characterization of the dynamic functional status of the organism. From this perspective, Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI-TOF) MS is a suitable platform for providing a high-throughput support to clinics. Areas covered: This review aims to provide an updated overview of MALDI-TOF MS applications in clinical proteomics. The most relevant features of this analysis have been discussed, highlighting both pre-analytical and analytical factors that are crucial in proteomics studies. Particular emphasis is placed on biofluids proteomics for biomarkers discovery and on recent progresses in clinical microbiology, drug monitoring, and minimal residual disease (MRD). Expert commentary: Despite some analytical limitations, the latest technological advances together with the easiness of use, the low time and low cost consuming and the high throughput are making MALDI-TOF MS instruments very attractive for the clinical practice. These features offer a significant potential for the routine of the clinical laboratory and ultimately for personalized medicine.
Assuntos
Proteômica , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Líquidos Corporais/metabolismo , Descoberta de Drogas , Humanos , Neoplasia Residual/metabolismoRESUMO
The Mitochondrial Human Proteome Project aims at understanding the function of the mitochondrial proteome and its crosstalk with the proteome of other organelles. Being able to choose a suitable and validated enrichment protocol of functional mitochondria, based on the specific needs of the downstream proteomics analysis, would greatly help the researchers in the field. Mitochondrial fractions from ten model cell lines were prepared using three enrichment protocols and analyzed on seven different LC-MS/MS platforms. All data were processed using neXtProt as reference database. The data are available for the Human Proteome Project purposes through the ProteomeXchange Consortium with the identifier PXD007053. The processed data sets were analyzed using a suite of R routines to perform a statistical analysis and to retrieve subcellular and submitochondrial localizations. Although the overall number of identified total and mitochondrial proteins was not significantly dependent on the enrichment protocol, specific line to line differences were observed. Moreover, the protein lists were mapped to a network representing the functional mitochondrial proteome, encompassing mitochondrial proteins and their first interactors. More than 80% of the identified proteins resulted in nodes of this network but with a different ability in coisolating mitochondria-associated structures for each enrichment protocol/cell line pair.
Assuntos
Mitocôndrias/química , Proteoma/fisiologia , Proteômica/normas , Linhagem Celular , Cromatografia Líquida , Humanos , Itália , Proteínas Mitocondriais/análise , Mapas de Interação de Proteínas/fisiologia , Espectrometria de Massas em TandemRESUMO
BACKGROUND: Myxomatous mitral valve disease (MVD) is the most common acquired heart disease in dogs, and the Cavalier King Charles Spaniel (CKCS) is the most studied breed because of the high prevalence, early onset and hereditary component evidenced in the breed. MVD has different severity levels, and there are many practical limitations in identifying its asymptomatic stages. Proteomic techniques are valuable for studying the proteins and peptides involved in cardiovascular diseases, including the period prior to the clinical onset of the disease. The aim of this study was to identify the serum proteins that were differentially expressed in healthy CKCS and those affected by MVD in mild to severe stages. Proteomics analysis was performed using two-dimensional gel electrophoresis separation and a bioinformatics analysis for the detection of differentially expressed spots. In a comparative analysis, protein spots with a p < 0.05 (ANOVA) were considered statistically significant and were excised from the gels for analysis by MALDI-TOF-MS for protein identification. RESULTS: Eight proteins resulted differentially expressed among the groups and significantly related to the progression of the disease. In mild affected group versus healthy dogs complement factor H isoform 2, inhibitor of carbonic anhydrase, hemopexin, dystrobrevin beta isoform X7 and CD5 molecule-like resulted to be down-regulated, whereas fibronectin type-III domain-containing protein 3A isoform X4 was up-regulated. In severe affected dogs versus healthy group complement factor H isoform 2, calpain-3 isoform X2, dystrobrevin beta isoform X7, CD5 molecule-like and l-2-hydroxyglutarate dehydrogenase resulted to be down-regulated. Complement factor H isoform 2, calpain-3 isoform X2, dystrobrevin beta isoform X7, CD5 molecule-like and hydroxyglutarate dehydrogenase were found to be down-regulated in mild affected group versus healthy dogs. All of these proteins except complement factor H followed a decreasing trend according to the progression of the pathology. CONCLUSION: The differential expression of serum proteins demonstrates the possibility these might be valuable for the detection and monitoring of the disease. Further longitudinal studies are required to determine whether differential protein expression occurs sufficiently early in the progression of the disease and with sufficient predictive value to allow proteomics analysis to be used as an early detection and on-line diagnostic tool.
Assuntos
Doenças do Cão/sangue , Doenças das Valvas Cardíacas/veterinária , Proteoma , Animais , Proteínas Sanguíneas/análise , Cruzamento , Estudos de Casos e Controles , Doenças do Cão/diagnóstico , Cães , Feminino , Doenças das Valvas Cardíacas/sangue , Doenças das Valvas Cardíacas/diagnóstico , Masculino , Valva Mitral/patologia , ProteômicaRESUMO
OBJECTIVE: Amyotrophic lateral sclerosis (ALS) is a motor neuron disease whose pathophysiological deficits, causing impairment in motor function, are largely unknown. Here we propose that hydrogen sulfide (H2 S), as a glial-released inflammatory factor, contributes to ALS-mediated motor neuron death. METHODS: H2 S concentrations were analyzed in the cerebrospinal fluid of 37 sporadic ALS patients and 14 age- and gender-matched controls, in tissues of a familial ALS (fALS) mouse model, and in spinal cord culture media by means of a specific and innovative high-performance liquid chromatography method. The effects of H2 S on motor neurons cultures was analyzed immunohistochemically and by patch clamp recordings and microfluorometry. RESULTS: We found a significantly high level of H2 S in the spinal fluid of the ALS patients. Consistently, we found increased levels of H2 S in the tissues and in the media from mice spinal cord cultures bearing the fALS mutation SOD1G93A. In addition, NaHS, an H2 S donor, added to spinal culture, obtained from control C57BL/6J mice, is toxic for motor neurons, and induces an intracellular Ca(2+) increase, attenuated by the intracytoplasmatic application of adenosine triphosphate. We further show that H2 S is mainly released by astrocytes and microglia. INTERPRETATION: This study unravels H2 S as an astroglial mediator of motor neuron damage possibly involved in the cellular death characterizing ALS.
Assuntos
Esclerose Lateral Amiotrófica/líquido cefalorraquidiano , Esclerose Lateral Amiotrófica/diagnóstico , Sulfeto de Hidrogênio/líquido cefalorraquidiano , Idoso , Animais , Biomarcadores/líquido cefalorraquidiano , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Pessoa de Meia-Idade , Técnicas de Cultura de Órgãos , Medula Espinal/metabolismoRESUMO
Mycobacterium avium subsp. paratuberculosis (MAP) is the cause of a chronic enteritis of ruminants (bovine paratuberculosis (PTB)--Johne's disease) that is associated with enormous worldwide economic losses for the animal production. Diagnosis is based on observation of clinical signs, the detection of antibodies in milk or serum, or evaluation of bacterial culture from feces. The limit of these methods is that they are not able to detect the disease in the subclinical stage and are applicable only when the disease is already advanced. For this reason, the main purpose of this study is to use the MAP proteome to detect novel immunoreactive proteins that may be helpful for PTB diagnoses. 2DE and 2D immunoblotting of MAP proteins were performed using sera of control cattle and PTB-infected cattle in order to highlight the specific immunoreactive proteins. Among the assigned identifiers to immunoreactive spots it was found that most of them correspond to surface-located proteins while three of them have never been described before as antigens. The identification of these proteins improves scientific knowledge that could be useful for PTB diagnoses. The sequence of the identified protein can be used for the synthesis of immunoreactive peptides that could be screened for their immunoreaction against bovine sera infected with MAP. All MS data have been deposited in the ProteomeXchange consortium with identifier PXD001159 and DOI 10.6019/PXD001159.
Assuntos
Proteínas de Bactérias/análise , Proteínas de Bactérias/imunologia , Doenças dos Bovinos/microbiologia , Mycobacterium avium subsp. paratuberculosis/imunologia , Paratuberculose/microbiologia , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Antígenos de Bactérias/análise , Antígenos de Bactérias/imunologia , Bovinos , Eletroforese em Gel BidimensionalRESUMO
Measurement of biochemical markers represents an important aid to clinicians in the early diagnosis and prognosis of neurological diseases. Many factors can contribute to increase the chances that a biomarker study becomes successful. In a cerebrospinal fluid analysis (CSF), more than 84% of laboratory errors can be attributed to several preanalytical variables that include CSF collection, storage, and freeze thawing cycles. In this concept paper, we focus on some critical issues arising from basic proteomics investigation in order to highlight some key elements of CSF quality control. Furthermore, we propose a direct assessment of sample quality (DASQ) by applying a fast MALDI-TOF-MS methodology to evaluate molecular features of sample degradation and oxidation. We propose DASQ as a fast and simple initial step to be included in large-scale projects for neurological biomarker studies. In fact, such a procedure will improved the development of standardized protocols in order to have well-characterized CSF biobanks.
Assuntos
Biomarcadores/líquido cefalorraquidiano , Testes de Química Clínica/normas , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/normas , Humanos , Doenças Neurodegenerativas/diagnóstico , Controle de Qualidade , Manejo de EspécimesRESUMO
Among the most common stable-isotope labeling strategies, the reaction of formaldehyde with peptides in the presence of NaCNBH3 features many attractive aspects that are conducive to its employment in quantitation experiments in proteomics. Reductive amination, with formaldehyde and d(2)-formaldehyde, is reported to be a fast, easy, and specific reaction, undoubtedly inexpensive if compared with commercially available kits for differential isotope coding. Acetaldehyde and d(4)-acetaldehyde could be employed as well without a substantial increase in terms of cost, and should provide a wider spacing between the differentially tagged peptides in the mass spectrum. Nevertheless, only a single paper reports about a diethylation approach for quantitation. We undertook a systematic analytical investigation on the reductive amination of some standard peptides pointing out the occasional occurrence of side reactions in dependence of pH or reagents order of addition, particularly observing the formation of cyclic adducts ascribable to rearrangements involving the generated Schiff-base and all the nucleophilic sites of its chemical environment. We also tried to evaluate how much this side-products amount may impair isotope coded relative quantitation.
Assuntos
Aminação , Oligopeptídeos/análise , Oligopeptídeos/química , Cromatografia Líquida de Alta Pressão , Formaldeído/química , Concentração de Íons de Hidrogênio , Marcação por Isótopo , Metilação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Redox dysregulation, an imbalance between oxidants and antioxidants, is crucial in the pathogenesis of various neurodegenerative diseases. Within this context, the "redoxome" encompasses the network of redox molecules collaborating to maintain cellular redox balance and signaling. Among these, cysteine-sensitive proteins are fundamental for this homeostasis. Due to their reactive thiol groups, cysteine (Cys) residues are particularly susceptible to oxidative post-translational modifications (PTMs) induced by free radicals (reactive oxygen, nitrogen, and sulfur species) which profoundly affect protein functions. Cys-PTMs, forming what is referred to as "cysteinet" in the redox proteome, are essential for redox signaling in both physiological and pathological conditions, including neurodegeneration. Such modifications significantly influence protein misfolding and aggregation, key hallmarks of neurodegenerative diseases such as Alzheimer's, Parkinson's, and notably, amyotrophic lateral sclerosis (ALS). This review aims to explore the complex landscape of cysteine PTMs in the cellular redox environment, elucidating their impact on neurodegeneration at protein level. By investigating specific cysteine-sensitive proteins and the regulatory networks involved, particular emphasis is placed on the link between redox dysregulation and ALS, highlighting this pathology as a prime example of a neurodegenerative disease wherein such redox dysregulation is a distinct hallmark.
RESUMO
REM sleep is critical for memory, emotion, and cognition. Manipulating brain activity during REM could improve our understanding of its function and benefits. Earlier studies have suggested that auditory stimulation in REM might modulate REM time and reduce rapid eye movement density. Building on this, we studied the cognitive effects and electroencephalographic responses related to such stimulation. We used acoustic stimulation locked to eye movements during REM and compared two overnight conditions (stimulation and no-stimulation). We evaluated the impact of this stimulation on REM sleep duration and electrophysiology, as well as two REM-sensitive memory tasks: visual discrimination and mirror tracing. Our results show that this auditory stimulation in REM decreases the rapid eye movements that characterize REM sleep and improves performance on the visual task but is detrimental to the mirror tracing task. We also observed increased beta-band activity and decreased theta-band activity following stimulation. Interestingly, these spectral changes were associated with changes in behavioural performance. These results show that acoustic stimulation can modulate REM sleep and suggest that different memory processes underpin its divergent impacts on cognitive performance.
Assuntos
Eletroencefalografia , Sono REM , Sono REM/fisiologia , Estimulação Acústica , Cognição , EletrofisiologiaRESUMO
Brain insulin resistance links the failure of energy metabolism with cognitive decline in both type 2 Diabetes Mellitus (T2D) and Alzheimer's disease (AD), although the molecular changes preceding overt brain insulin resistance remain unexplored. Abnormal biliverdin reductase-A (BVR-A) levels were observed in both T2D and AD and were associated with insulin resistance. Here, we demonstrate that reduced BVR-A levels alter insulin signaling and mitochondrial bioenergetics in the brain. Loss of BVR-A leads to IRS1 hyper-activation but dysregulates Akt-GSK3ß complex in response to insulin, hindering the accumulation of pGSK3ßS9 into the mitochondria. This event impairs oxidative phosphorylation and fosters the activation of the mitochondrial Unfolded Protein Response (UPRmt). Remarkably, we unveil that BVR-A is required to shuttle pGSK3ßS9 into the mitochondria. Our data sheds light on the intricate interplay between insulin signaling and mitochondrial metabolism in the brain unraveling potential targets for mitigating the development of brain insulin resistance and neurodegeneration.
Assuntos
Glicogênio Sintase Quinase 3 beta , Resistência à Insulina , Insulina , Mitocôndrias , Oxirredutases atuantes sobre Doadores de Grupo CH-CH , Transdução de Sinais , Glicogênio Sintase Quinase 3 beta/metabolismo , Mitocôndrias/metabolismo , Fosforilação , Animais , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/metabolismo , Insulina/metabolismo , Camundongos , Humanos , Encéfalo/metabolismo , Proteínas Substratos do Receptor de Insulina/metabolismo , Resposta a Proteínas não Dobradas , Diabetes Mellitus Tipo 2/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Doença de Alzheimer/metabolismoRESUMO
Transthyretin (TTR) is a homotetrameric protein of the CNS that plays a role of as the major thyroxine (T4) carrier from blood to cerebrospinal fluid (CSF). T4 physiologically helps oligodendrocyte precursor cells to turn into myelinating oligodendrocytes, enhancing remyelination after myelin sheet damage. We investigated post-translational oxidative modifications of serum and CSF TTR in multiple sclerosis subjects, highlighting high levels of S-sulfhydration and S-sulfonation of cysteine in position ten only in the cerebral TTR, which correlate with an anomalous TTR protein folding as well as with disease duration. Moreover, we found low levels of free T4 in CSF of multiple sclerosis patients, suggestive of a potential role of these modifications in T4 transport into the brain.