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BACKGROUND: Intrauterine fetal demise is a recognized complication of coronavirus disease 2019 in pregnant women and is associated with histopathological placental lesions. The pathological mechanism and virus-induced immune response in the placenta are not fully understood. A detailed description of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced inflammation in the placenta during fetal demise is crucial for improved clinical management. CASE PRESENTATION: We report the case of a 27-week gestation SARS-CoV-2-asymptomatic unvaccinated pregnant woman without comorbidities or other risk factors for negative pregnancy outcomes with a diagnosis of intrauterine fetal demise. Histopathological findings corresponded to patterns of subacute inflammation throughout the anatomic compartments of the placenta, showing severe chorioamnionitis, chronic villitis and deciduitis, accompanied by maternal and fetal vascular malperfusion. Our immunohistochemistry results revealed infiltration of CD68+ macrophages, CD56+ Natural Killer cells and scarce CD8+ T cytotoxic lymphocytes at the site of placental inflammation, with the SARS-CoV-2 nucleocapsid located in stromal cells of the chorion and chorionic villi, and in decidual cells. CONCLUSION: This case describes novel histopathological lesions of inflammation with infiltration of plasma cells, neutrophils, macrophages, and natural killer cells associated with malperfusion in the placenta of a SARS-CoV-2-infected asymptomatic woman with intrauterine fetal demise. A better understanding of the inflammatory effects exerted by SARS-CoV-2 in the placenta will enable strategies for better clinical management of pregnant women unvaccinated for SARS-CoV-2 to avoid fatal fetal outcomes during future transmission waves.
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COVID-19 , Muerte Fetal , Placenta , Complicaciones Infecciosas del Embarazo , SARS-CoV-2 , Humanos , Femenino , Embarazo , COVID-19/complicaciones , COVID-19/inmunología , Muerte Fetal/etiología , Adulto , Placenta/patología , Placenta/virología , Corioamnionitis/patología , Inflamación , Células Asesinas Naturales/inmunologíaRESUMEN
Genome damage and their defective repair have been etiologically linked to degenerating neurons in many subtypes of amyotrophic lateral sclerosis (ALS) patients; however, the specific mechanisms remain enigmatic. The majority of sporadic ALS patients feature abnormalities in the transactivation response DNA-binding protein of 43 kDa (TDP-43), whose nucleo-cytoplasmic mislocalization is characteristically observed in spinal motor neurons. While emerging evidence suggests involvement of other RNA/DNA binding proteins, like FUS in DNA damage response (DDR), the role of TDP-43 in DDR has not been investigated. Here, we report that TDP-43 is a critical component of the nonhomologous end joining (NHEJ)-mediated DNA double-strand break (DSB) repair pathway. TDP-43 is rapidly recruited at DSB sites to stably interact with DDR and NHEJ factors, specifically acting as a scaffold for the recruitment of break-sealing XRCC4-DNA ligase 4 complex at DSB sites in induced pluripotent stem cell-derived motor neurons. shRNA or CRISPR/Cas9-mediated conditional depletion of TDP-43 markedly increases accumulation of genomic DSBs by impairing NHEJ repair, and thereby, sensitizing neurons to DSB stress. Finally, TDP-43 pathology strongly correlates with DSB repair defects, and damage accumulation in the neuronal genomes of sporadic ALS patients and in Caenorhabditis elegans mutant with TDP-1 loss-of-function. Our findings thus link TDP-43 pathology to impaired DSB repair and persistent DDR signaling in motor neuron disease, and suggest that DSB repair-targeted therapies may ameliorate TDP-43 toxicity-induced genome instability in motor neuron disease.
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Esclerosis Amiotrófica Lateral/genética , Esclerosis Amiotrófica Lateral/metabolismo , Roturas del ADN de Doble Cadena , Reparación del ADN , Proteínas de Unión al ADN/metabolismo , Animales , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Reparación del ADN por Unión de Extremidades , Proteínas de Unión al ADN/genética , Humanos , Neuronas Motoras/metabolismo , Unión Proteica , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismoRESUMEN
Dominant mutations in the RNA/DNA-binding protein TDP-43 have been linked to amyotrophic lateral sclerosis (ALS). Here, we screened genomic DNA extracted from spinal cord specimens of sporadic ALS patients for mutations in the TARDBP gene and identified a patient specimen with previously reported Q331K mutation. The patient spinal cord tissue with Q331K mutation showed accumulation of higher levels of DNA strand breaks and the DNA double-strand break (DSB) marker γH2AX, compared to age-matched controls, suggesting a role of the Q331K mutation in genome-damage accumulation. Using conditional SH-SY5Y lines ectopically expressing wild-type (WT) or Q331K-mutant TDP-43, we confirmed the increased cytosolic sequestration of the poly-ubiquitinated and aggregated form of mutant TDP-43, which correlated with increased genomic DNA strand breaks, activation of the DNA damage response factors phospho-ataxia-telangiectasia mutated (ATM), phospho-53BP1, γH2AX and neuronal apoptosis. We recently reported the involvement of WT TDP-43 in non-homologous end joining (NHEJ)-mediated DSB repair, where it acts as a scaffold for the recruitment of XRCC4-DNA ligase 4 complex. Here, the mutant TDP-43, due to its reduced interaction and enhanced cytosolic mislocalization, prevented the nuclear translocation of XRCC4-DNA ligase 4. Consistently, the mutant cells showed significantly reduced DNA strand break sealing activity and were sensitized to DNA-damaging drugs. In addition, the mutant cells showed elevated levels of reactive oxygen species, suggesting both dominant negative and loss-of-function effects of the mutation. Together, our study uncovered an association of sporadic Q331K mutation with persistent genome damage accumulation due to both damage induction and repair defects.
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Esclerosis Amiotrófica Lateral/genética , ADN Ligasa (ATP)/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Mutación , Esclerosis Amiotrófica Lateral/metabolismo , Apoptosis/genética , Línea Celular , ADN/metabolismo , Roturas del ADN de Doble Cadena , ADN Ligasa (ATP)/genética , Reparación del ADN , Humanos , Neuronas/metabolismo , Polimorfismo de Nucleótido Simple , Proteínas de Unión al ARN/metabolismo , Médula Espinal/metabolismo , Translocación GenéticaRESUMEN
TDP-43 mislocalization and aggregation are key pathological features of motor neuron diseases (MND) including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, transgenic hTDP-43 WT or ΔNLS-overexpression animal models mainly capture late-stages TDP-43 proteinopathy, and do not provide a complete understanding of early motor neuron-specific pathology during pre-symptomatic phases. We have now addressed this shortcoming by generating a new endogenous knock-in (KI) mouse model using a combination of CRISPR/Cas9 and FLEX Cre-switch strategy for the conditional expression of a mislocalized Tdp-43ΔNLS variant of mouse Tdp-43. This variant is either expressed conditionally in whole mice or specifically in the motor neurons. The mice exhibit loss of nuclear Tdp-43 concomitant with its cytosolic accumulation and aggregation in targeted cells, leading to increased DNA double-strand breaks (DSBs), signs of inflammation and DNA damage-associated cellular senescence. Notably, unlike WT Tdp43 which functionally interacts with Xrcc4 and DNA Ligase 4, the key DSB repair proteins in the non-homologous end-joining (NHEJ) pathway, the Tdp-43ΔNLS mutant sequesters them into cytosolic aggregates, exacerbating neuronal damage in mice brain. The mutant mice also exhibit myogenic degeneration in limb muscles and distinct motor deficits, consistent with the characteristics of MND. Our findings reveal progressive degenerative mechanisms in motor neurons expressing endogenous Tdp-43ΔNLS mutant, independent of TDP-43 overexpression or other confounding etiological factors. Thus, this unique Tdp-43 KI mouse model, which displays key molecular and phenotypic features of Tdp-43 proteinopathy, offers a significant opportunity to further characterize the early-stage progression of MND and also opens avenues for developing DNA repair-targeted approaches for treating TDP-43 pathology-linked neurodegenerative diseases.
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Amyotrophic lateral sclerosis type 6 (ALS6) is a familial subtype of ALS linked to Fused in Sarcoma (FUS) gene mutation. FUS mutations lead to decreased global protein synthesis, but the mechanism that drives this has not been established. Here, we used ALS6 patient-derived induced pluripotent stem cells (hIPSCs) to study the effect of the ALS6 FUSR521H mutation on the translation machinery in motor neurons (MNs). We find, in agreement with findings of others, that protein synthesis is decreased in FUSR521H MNs. Furthermore, FUSR521H MNs are more sensitive to oxidative stress and display reduced expression of TGF-ß and mTORC gene pathways when stressed. Finally, we show that IFNγ treatment reduces apoptosis of FUSR521H MNs exposed to oxidative stress and partially restores the translation rates in FUSR521H MNs. Overall, these findings suggest that a functional IFNγ response is important for FUS-mediated protein synthesis, possibly by FUS nuclear translocation in ALS6.
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Esclerosis Amiotrófica Lateral , Humanos , Esclerosis Amiotrófica Lateral/genética , Esclerosis Amiotrófica Lateral/metabolismo , Neuronas Motoras/metabolismo , Mutación , Estrés Oxidativo , Proteína FUS de Unión a ARN/genéticaRESUMEN
Mesenchymal stem cells (MSCs) experience functional decline with systemic aging, resulting in reduced proliferation, increased senescence, and lower differentiation potential. The placenta represents a valuable source of MSCs, but the possible effect of donor age on the properties of placenta-derived mesenchymal stem cells (PDMSCs) has not been thoroughly studied. Thus, the aim of this study was to underscore the effect of maternal age on the biological characteristics and stemness properties of PDMSCs. PDMSCs were isolated from 5 donor age groups (A: 18-21, B: 22-25, C: 26-30, D:31-35 and E: ≥36 years) for comparison of morphological, proliferative and differentiation properties. The pluripotency markers NANOG, OCT4, and SSEA4, as well as multipotency and differentiation markers, showed higher expression in PDMSCs from mothers aged 22-35 years, with up to a 7-fold increase in adipogenesis. Cumulative population doubling, cell growth curves, and colony-forming unit-fibroblast assays revealed higher self-renewal ability in donors 26-30 years old. An increase in the proliferative characteristics of PDMSCs correlated with increased telomere shortening, suggesting that shorter telomere lengths could be related to cellular division rather than aging. A clear understanding of the effect of maternal age on MSC regenerative potential will assist in increasing the effectiveness of future cell therapies.
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Diferenciación Celular/fisiología , Edad Materna , Células Madre Mesenquimatosas/fisiología , Placenta/citología , Acortamiento del Telómero/fisiología , Adolescente , Adulto , Proliferación Celular/fisiología , Femenino , Humanos , Embarazo , Adulto JovenRESUMEN
There is limited evidence regarding severe acute respiratory syndrome coronavirus 2 infection in the placenta of pregnant women who tested positive, and if this could be a route for vertical transmission of the virus in utero. We present the cases of 2 pregnant women in their third trimester who were admitted for delivery by cesarean delivery and who, through universal screening, tested positive for coronavirus disease 2019. The maternal and fetal sides of the placenta were sectioned from both patients for viral analysis. Real-time polymerase chain reaction analysis of the placental-extracted RNA revealed a severe acute respiratory syndrome coronavirus 2 infection on the fetal side of the placenta in both patients. The virus was isolated from the patient with the lowest cycle threshold value on the fetal side of the placenta. Whole genome sequencing showed that the virus detected in this placenta was from the B1 lineage. Immunohistochemical analysis of the placental tissue detected severe acute respiratory syndrome coronavirus 2 in the endothelial cells of chorionic villi vessels proximal to both the maternal and fetal sides, with a granular cytoplasmic pattern and perinuclear reinforcement. Histologic examination of the placenta also detected a dense infiltrate of lymphoid cells around decidual vessels and endothelial cells with cytopathic changes, especially on the maternal side. Nasopharyngeal swabs from the infants that were subjected to reverse transcription quantitative polymerase chain reaction testing were negative for severe acute respiratory syndrome coronavirus 2 at 24 hours after birth. A follow-up analysis of the infants for immunoglobin G and immunoglobin M expression, clinical manifestations, and long-term developmental abnormalities is recommended.
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Homologous recombination/end joining (HR/HEJ)-deficient cancers with BRCA mutations utilize alternative DNA double-strand break repair pathways, particularly alternative non-homologous end joining or microhomology-mediated end joining (alt-EJ/MMEJ) during S and G2 cell cycle phases. Depletion of alt-EJ factors, including XRCC1, PARP1 and POLQ, is synthetically lethal with BRCA2 deficiency; yet, XRCC1 roles in HR-deficient cancers and replication stress are enigmatic. Here, we show that after replication stress, XRCC1 forms an active repair complex with POLQ and MRE11 that supports alt-EJ activity in vitro. BRCA2 limits XRCC1 recruitment and repair complex formation to suppress alt-EJ at stalled forks. Without BRCA2 fork protection, XRCC1 enables cells to complete DNA replication at the expense of increased genome instability by promoting MRE11-dependent fork resection and restart. High XRCC1 and MRE11 gene expression negatively impacts Kaplan-Meier survival curves and hazard ratios for HR-deficient breast cancer patients in The Cancer Genome Atlas. The additive effects of depleting both BRCA2 and XRCC1 indicate distinct pathways for replication restart. Our collective data show that XRCC1-mediated processing contributes to replication fork degradation, replication restart and chromosome aberrations in BRCA2-deficient cells, uncovering new roles of XRCC1 and microhomology-mediated repair mechanisms in HR-deficient cancers, with implications for chemotherapeutic strategies targeting POLQ and PARP activities.
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Amyotrophic lateral sclerosis (ALS) is a degenerative motor neuron disease that has been linked to defective DNA repair. Many familial ALS patients harbor autosomal dominant mutations in the gene encoding the RNA/DNA binding protein 'fused in sarcoma' (FUS) commonly inducing its cytoplasmic mislocalization. Recent reports from our group and others demonstrate a role of FUS in maintaining genome integrity and the DNA damage response (DDR). FUS interacts with many DDR proteins and may regulate their recruitment at damage sites. Given the role of FUS in RNA transactions, here we explore whether FUS also regulates the expression of DDR factors. We performed RT2 PCR arrays for DNA repair and DDR signaling pathways in CRISPR/Cas9 FUS knockout (KO) and shRNA mediated FUS knockdown (KD) cells, which revealed significant (> 2-fold) downregulation of BRCA1, DNA ligase 4, MSH complex and RAD23B. Importantly, similar perturbations in these factors were also consistent in motor neurons differentiated from an ALS patient-derived induced pluripotent stem cell (iPSC) line with a FUS-P525L mutation, as well as in postmortem spinal cord tissue of sporadic ALS patients with FUS pathology. BRCA1 depletion has been linked to neuronal DNA double-strand breaks (DSBs) accumulation and cognitive defects. The ubiquitin receptor RAD23 functions both in nucleotide excision repair and proteasomal protein clearance pathway and is thus linked to neurodegeneration. Together, our study suggests that the FUS pathology perturbs DDR signaling via both its direct role and the effect on the expression of DDR genes. This underscors an intricate connections between FUS, genome instability, and neurodegeneration.
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Daño del ADN , Enfermedad de la Neurona Motora/metabolismo , Enfermedad de la Neurona Motora/patología , Proteína FUS de Unión a ARN/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Transducción de Señal , Daño del ADN/genética , Reparación del ADN/genética , Regulación de la Expresión Génica , Células HEK293 , Humanos , Enfermedad de la Neurona Motora/genética , Neuronas Motoras/metabolismo , Neuronas Motoras/patologíaRESUMEN
Amyotrophic lateral sclerosis (ALS), a common motor neuron disease affecting two per 100,000 people worldwide, encompasses at least five distinct pathological subtypes, including, ALS-SOD1, ALS-C9orf72, ALS-TDP-43, ALS-FUS and Guam-ALS. The etiology of a major subset of ALS involves toxicity of the TAR DNA-binding protein-43 (TDP-43). A second RNA/DNA binding protein, fused in sarcoma/translocated in liposarcoma (FUS/TLS) has been subsequently associated with about 1% of ALS patients. While mutations in TDP-43 and FUS have been linked to ALS, the key contributing molecular mechanism(s) leading to cell death are still unclear. One unique feature of TDP-43 and FUS pathogenesis in ALS is their nuclear clearance and simultaneous cytoplasmic aggregation in affected motor neurons. Since the discoveries in the last decade implicating TDP-43 and FUS toxicity in ALS, a majority of studies have focused on their cytoplasmic aggregation and disruption of their RNA-binding functions. However, TDP-43 and FUS also bind to DNA, although the significance of their DNA binding in disease-affected neurons has been less investigated. A recent observation of accumulated genomic damage in TDP-43 and FUS-linked ALS and association of FUS with neuronal DNA damage repair pathways indicate a possible role of deregulated DNA binding function of TDP-43 and FUS in ALS. In this review, we discuss the different ALS disease subtypes, crosstalk of etiopathologies in disease progression, available animal models and their limitations, and recent advances in understanding the specific involvement of RNA/DNA binding proteins, TDP-43 and FUS, in motor neuron diseases.
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Esclerosis Amiotrófica Lateral/genética , Proteínas de Unión al ADN/genética , Proteína FUS de Unión a ARN/genética , HumanosRESUMEN
La enfermedad de Wilson es una condición genética autosómica recesiva poco frecuente. Se ha identificado el gen ATP7B como el que codifica la proteína transportadora de cobre y su deficiencia lleva al acúmulo del metal en el cerebro, hígado y otros órganos vitales. Su diagnóstico clínico precoz es esencial para mejorar la calidad de vida del paciente. A continuación, se presenta el caso de un paciente de 20 años, masculino, con un cuadro clínico de 2 años de evolución de desinhibición, impulsividad, anartria y apraxia de la marcha, movimientos distónicos faciales y en 4 extremidades. Al examen físico se evidenció el anillo de Kayser Flescher a nivel ocular. En Resonancia Magnética Encefálica hiperintensidad en ganglios de la base y mesencéfalo en T2. Ceruloplasmina en suero 4.08 mg/dL. Cobre sérico 26.03ug/dL y cobre en orina de 24 horas 224.30ug/ 24h. Se confirma el diagnóstico de Enfermedad de Wilson, tratándose con D- Penicilamina, evidenciándose una evolución adecuada, con mejoría notable del cuadro neurológico. El tratamiento precoz permite una evolución favorable temprana del paciente, disminuyendo las secuelas neurológicas secundarias a la enfermedad; de ahí la importancia del reporte del presente caso.(AU)
BackgroundWilson's disease is a rare autosomal recessive genetic condition. The ATP7B gene has been identified as the one that encodes the copper transport protein and its deficiency leads to the accumulation of metal in the brain, liver and other vital organs. Your early clinical diagnosis is essential to improve the quality of life of the patient. Following we present the clinical case of a 20-year-old male patient who since 2 years ago, presented disinhibition, impulsivity, anartria and gait apraxia, facial dystonic movements and in extremities. To the physical exam, Kayser Flescher ring was present. In Brain Magnetic Resonance hyperintensity in Basal Ganglia and Midbrain. Serum Ceruloplasmin 4.08. Serum Copper 26.03. Urinary Cupper 224.30. The diagnosis of Wilson's disease is confirmed, treating with D-Penicillamine, evidencing an adequate evolution, with notable improvement of the neurological symptoms. Early treatment allows a favorable early evolution of the patient, reducing the neurological sequelae secondary to the disease; so that the importance of the report of this case.(AU)
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Humanos , Masculino , Adulto , ATPasas Transportadoras de Cobre/análisis , Degeneración Hepatolenticular/complicaciones , Degeneración Hepatolenticular/diagnóstico por imagen , Ceruloplasmina/químicaRESUMEN
The primary cause(s) of neuronal death in most cases of neurodegenerative diseases, including Alzheimer's and Parkinson's disease, are still unknown. However, the association of certain etiological factors, e.g., oxidative stress, protein misfolding/aggregation, redox metal accumulation and various types of damage to the genome, to pathological changes in the affected brain region(s) have been consistently observed. While redox metal toxicity received major attention in the last decade, its potential as a therapeutic target is still at a cross-roads, mostly because of the lack of mechanistic understanding of metal dyshomeostasis in affected neurons. Furthermore, previous studies have established the role of metals in causing genome damage, both directly and via the generation of reactive oxygen species (ROS), but little was known about their impact on genome repair. Our recent studies demonstrated that excess levels of iron and copper observed in neurodegenerative disease-affected brain neurons could not only induce genome damage in neurons, but also affect their repair by oxidatively inhibiting NEIL DNA glycosylases, which initiate the repair of oxidized DNA bases. The inhibitory effect was reversed by a combination of metal chelators and reducing agents, which underscore the need for elucidating the molecular basis for the neuronal toxicity of metals in order to develop effective therapeutic approaches. In this review, we have focused on the oxidative genome damage repair pathway as a potential target for reducing pro-oxidant metal toxicity in neurological diseases.
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Daño del ADN , Reparación del ADN , Genoma/genética , Metales/metabolismo , Enfermedades Neurodegenerativas/genética , Enfermedades Neurodegenerativas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Animales , Humanos , Oxidación-ReducciónRESUMEN
The toxicity of α-synuclein in the neuropathology of Parkinson's disease which includes its hallmark aggregation has been studied scrupulously in the last decade. Although little is known regarding the normal functions of α-synuclein, its association with membrane phospholipids suggests its potential role in signaling pathways. Following extensive evidences for its nuclear localization, we and others recently demonstrated DNA binding activity of α-synuclein that modulates its conformation as well as aggregation properties. Furthermore, we also underscored the similarities among various amyloidogenic proteins involved in neurodegenerative diseases including amyloid beta peptides and tau. Our more recent studies show that α-synuclein is glycated and glycosylated both in vitro and in neurons, significantly affecting its folding, oligomeric, and DNA binding properties. Glycated α-synuclein causes increased genome damage both via its direct interaction with DNA and by increased generation of reactive oxygen species as glycation byproduct. In this review, we discuss the mechanisms of glycation and other posttranslational modifications of α-synuclein, including phosphorylation and nitration, and their role in neuronal death in Parkinson's disease.
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Productos Finales de Glicación Avanzada/metabolismo , Enfermedad de Parkinson/metabolismo , alfa-Sinucleína/fisiología , Animales , Muerte Celular/fisiología , Glicosilación , Humanos , Enfermedad de Parkinson/patología , Fosforilación/fisiología , Unión Proteica/fisiología , Pliegue de Proteína , alfa-Sinucleína/efectos adversos , alfa-Sinucleína/toxicidadRESUMEN
Introducción: Ante el envejecimiento acelerado de la población cubana los trastornos cognitivos se han convertido en creciente problema y un reto para nuestro sistema de salud. Objetivo: Describir la influencia de las determinantes del estado de salud de la población en el desarrollo de los trastornos cognitivos. Fuente de datos: Se consultaron 113 artículos en la Biblioteca Virtual Scielo y en las bases de datos Medline, Google Scholar, Cochrane y PubMed, en idioma Inglés y Español. Se seleccionaron 40, publicados en revistas nacionales e internacionales de gran impacto, por autores considerados expertos en esta temática. Síntesis de los datos: Además de factores biológicos y genéticos, existen determinantes psicosociales como el nivel educacional y los estilos de vida que pudieran incidir en la aparición y desarrollo de las demencias. Entre estos últimos, aparecen los hábitos tóxicos, las relaciones sociales, antecedentes de depresión, nivel socioeconómico y otros. Conclusiones: La influencia de los determinantes del estado de salud de la población en el desarrollo de los trastornos cognitivos, es notable. Es necesario el estudio de estos determinantes y su contribución a la puesta en marcha de estrategias de intervención comunitaria que ayuden, sobre todo, a la población más vulnerable a tener una mejor calidad de vida(AU).
Introduction: The accelerated aging of the Cuban population is an alert to the high prevalence of dementias and other chronic diseases. Objective: To describe the influence of health status determinants of the population in the development of cognitive disorders. Data source: 113 articles in the Scielo Virtual Library and in Medline, Google Scholar, Cochrane and PubMed databases were consulted, both in English and Spanish. 38 of the selected were published in national and international magazines of great impact, by authors considered experts in this subject. Synthesis of data: In addition to biological and genetic factors, there are other psychosocial determinants such as education and lifestyles that may have an impact on the onset and development of dementia. Among the latter are toxic habits, social interactions, sleep, and depressive states. These states may be considered as a psychological reaction to incipient cognitive worsening or as an early manifestation of dementia. Conclusions: The influence of population´s health status determinants in the development of cognitive disorders is remarkable. Given the accelerated aging of the Cuban population, cognitive disorders become a growing health problem. More research is needed and the results of this may contribute to a better understanding of the epidemiological behavior of these disorders. It is necessary, through intersectoral work, the implementation of community intervention strategies that help above all most vulnerable population to have a better life quality(AU)
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Humanos , Masculino , Femenino , Calidad de Vida/psicología , Dinámica Poblacional , Trastornos del Conocimiento/etiología , Trastornos del Conocimiento/etnología , Trastornos del Conocimiento/epidemiología , Demencia/etiología , Determinantes Sociales de la Salud/etnología , Envejecimiento Cognitivo/psicología , CubaRESUMEN
BACKGROUND: Deoxyribonucleic acid (DNA) topology plays a critical role in maintaining the integrity of the genome and cellular functions. Although changes in DNA conformation and structural dynamics in the brain have been associated with various neurological disorders, its precise role in the pathogenesis is still unclear. Previous studies from our laboratory have shown that there is a conformational change in the genomic DNA of Parkinson's disease (PD) (B to altered B-DNA) and Alzheimer's disease brain (B to Z-DNA). However, there is limited information on the mechanism on DNA dynamics changes in brain. OBJECTIVE: In the present study, we have investigated the DNA conformation and sequence specific binding ability of α-Synuclein and Tau with reference to B-DNA and Z-DNA using oligonucleotide (CGCGCGCG)(2) as a novel model DNA system. This sequence is predominantly present in the promoter region of the genes of biological relevance. MATERIALS AND METHODS: Natively, (CGCGCGCG)(2) sequence exists in B-DNA conformation, but in the presence of high sodium concentration (4 M NaCl), the oligo converts into Z-DNA form. We used circular dichroism, melting temperature and fluorescence studies to understand protein-DNA interactions. RESULTS: CD studies indicated that both α-Synuclein and Tau bind to B-DNA conformation of (CGCGCGCG)(2) and induce altered B-form. Further, these proteins increased the melting temperature and decreased the number of EtBr molecules bound per base pair of DNA in B-form indicating that DNA stability is favored to alter B-DNA conformation, which could be an intermediate form favoring Z-DNA conformation. Moreover, both α-Synuclein and Tau also bound to disease-linked Z-DNA conformation of (CGCGCGCG)(2) and further stabilized the Z-conformation. CONCLUSIONS: The present study provides vital mechanistic information on Synuclein and Tau binding to DNA in a conformation-specific manner causing conformational transition. Furthermore, both the proteins stabilize Z-DNA conformation. These have altered minor and major groove patterns and thus may have significant biological implications in relevance to gene expression pattern in neurodegeneration. We discuss the implications of α-Synuclein/Tau binding to DNA and stabilizing the altered conformations of DNA in neuronal cell dysfunction.