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1.
Nat Immunol ; 23(1): 40-49, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34937928

RESUMO

SARS-CoV-2 infection is generally mild or asymptomatic in children but a biological basis for this outcome is unclear. Here we compare antibody and cellular immunity in children (aged 3-11 years) and adults. Antibody responses against spike protein were high in children and seroconversion boosted responses against seasonal Beta-coronaviruses through cross-recognition of the S2 domain. Neutralization of viral variants was comparable between children and adults. Spike-specific T cell responses were more than twice as high in children and were also detected in many seronegative children, indicating pre-existing cross-reactive responses to seasonal coronaviruses. Importantly, children retained antibody and cellular responses 6 months after infection, whereas relative waning occurred in adults. Spike-specific responses were also broadly stable beyond 12 months. Therefore, children generate robust, cross-reactive and sustained immune responses to SARS-CoV-2 with focused specificity for the spike protein. These findings provide insight into the relative clinical protection that occurs in most children and might help to guide the design of pediatric vaccination regimens.


Assuntos
Anticorpos Antivirais/imunologia , Coronavirus Humano 229E/imunologia , Coronavirus Humano OC43/imunologia , Proteção Cruzada/imunologia , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Imunidade Adaptativa/imunologia , Adulto , Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , Vacinas contra COVID-19/imunologia , Criança , Pré-Escolar , Reações Cruzadas/imunologia , Humanos
2.
Mol Cell ; 84(4): 640-658.e10, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38266639

RESUMO

The Bloom syndrome helicase BLM interacts with topoisomerase IIIα (TOP3A), RMI1, and RMI2 to form the BTR complex, which dissolves double Holliday junctions and DNA replication intermediates to promote sister chromatid disjunction before cell division. In its absence, structure-specific nucleases like the SMX complex (comprising SLX1-SLX4, MUS81-EME1, and XPF-ERCC1) can cleave joint DNA molecules instead, but cells deficient in both BTR and SMX are not viable. Here, we identify a negative genetic interaction between BLM loss and deficiency in the BRCA1-BARD1 tumor suppressor complex. We show that this is due to a previously overlooked role for BARD1 in recruiting SLX4 to resolve DNA intermediates left unprocessed by BLM in the preceding interphase. Consequently, cells with defective BLM and BRCA1-BARD1 accumulate catastrophic levels of chromosome breakage and micronucleation, leading to cell death. Thus, we reveal mechanistic insights into SLX4 recruitment to DNA lesions, with potential clinical implications for treating BRCA1-deficient tumors.


Assuntos
Proteínas de Ligação a DNA , Recombinases , Humanos , DNA/genética , Reparo do DNA , Replicação do DNA , DNA Cruciforme , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Recombinases/genética , RecQ Helicases/genética , RecQ Helicases/metabolismo
3.
Mol Cell ; 82(18): 3382-3397.e7, 2022 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-36002001

RESUMO

Aberrant replication causes cells lacking BRCA2 to enter mitosis with under-replicated DNA, which activates a repair mechanism known as mitotic DNA synthesis (MiDAS). Here, we identify genome-wide the sites where MiDAS reactions occur when BRCA2 is abrogated. High-resolution profiling revealed that these sites are different from MiDAS at aphidicolin-induced common fragile sites in that they map to genomic regions replicating in the early S-phase, which are close to early-firing replication origins, are highly transcribed, and display R-loop-forming potential. Both transcription inhibition in early S-phase and RNaseH1 overexpression reduced MiDAS in BRCA2-deficient cells, indicating that transcription-replication conflicts (TRCs) and R-loops are the source of MiDAS. Importantly, the MiDAS sites identified in BRCA2-deficient cells also represent hotspots for genomic rearrangements in BRCA2-mutated breast tumors. Thus, our work provides a mechanism for how tumor-predisposing BRCA2 inactivation links transcription-induced DNA damage with mitotic DNA repair to fuel the genomic instability characteristic of cancer cells.


Assuntos
Replicação do DNA , Mitose , Afidicolina/farmacologia , Proteína BRCA2/genética , Sítios Frágeis do Cromossomo/genética , DNA/genética , Dano ao DNA , Instabilidade Genômica , Humanos , Mitose/genética
4.
PLoS Biol ; 22(2): e3002494, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38319934

RESUMO

Effective interactions with the environment rely on the integration of multisensory signals: Our brains must efficiently combine signals that share a common source, and segregate those that do not. Healthy ageing can change or impair this process. This functional magnetic resonance imaging study assessed the neural mechanisms underlying age differences in the integration of auditory and visual spatial cues. Participants were presented with synchronous audiovisual signals at various degrees of spatial disparity and indicated their perceived sound location. Behaviourally, older adults were able to maintain localisation accuracy. At the neural level, they integrated auditory and visual cues into spatial representations along dorsal auditory and visual processing pathways similarly to their younger counterparts but showed greater activations in a widespread system of frontal, temporal, and parietal areas. According to multivariate Bayesian decoding, these areas encoded critical stimulus information beyond that which was encoded in the brain areas commonly activated by both groups. Surprisingly, however, the boost in information provided by these areas with age-related activation increases was comparable across the 2 age groups. This dissociation-between comparable information encoded in brain activation patterns across the 2 age groups, but age-related increases in regional blood-oxygen-level-dependent responses-contradicts the widespread notion that older adults recruit new regions as a compensatory mechanism to encode task-relevant information. Instead, our findings suggest that activation increases in older adults reflect nonspecific or modulatory mechanisms related to less efficient or slower processing, or greater demands on attentional resources.


Assuntos
Mapeamento Encefálico , Percepção Visual , Humanos , Idoso , Teorema de Bayes , Percepção Visual/fisiologia , Encéfalo/fisiologia , Atenção/fisiologia , Estimulação Acústica/métodos , Percepção Auditiva/fisiologia , Estimulação Luminosa/métodos , Imageamento por Ressonância Magnética
5.
Mol Cell ; 74(3): 571-583.e8, 2019 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-30898438

RESUMO

In mitosis, cells inactivate DNA double-strand break (DSB) repair pathways to preserve genome stability. However, some early signaling events still occur, such as recruitment of the scaffold protein MDC1 to phosphorylated histone H2AX at DSBs. Yet, it remains unclear whether these events are important for maintaining genome stability during mitosis. Here, we identify a highly conserved protein-interaction surface in MDC1 that is phosphorylated by CK2 and recognized by the DNA-damage response mediator protein TOPBP1. Disruption of MDC1-TOPBP1 binding causes a specific loss of TOPBP1 recruitment to DSBs in mitotic but not interphase cells, accompanied by mitotic radiosensitivity, increased micronuclei, and chromosomal instability. Mechanistically, we find that TOPBP1 forms filamentous structures capable of bridging MDC1 foci in mitosis, indicating that MDC1-TOPBP1 complexes tether DSBs until repair is reactivated in the following G1 phase. Thus, we reveal an important, hitherto-unnoticed cooperation between MDC1 and TOPBP1 in maintaining genome stability during cell division.


Assuntos
Proteínas de Transporte/genética , Instabilidade Cromossômica/genética , Proteínas de Ligação a DNA/genética , Mitose/genética , Proteínas Nucleares/genética , Transativadores/genética , Proteínas Adaptadoras de Transdução de Sinal , Proteínas de Ciclo Celular , Quebras de DNA de Cadeia Dupla , Dano ao DNA/genética , Reparo do DNA/genética , Fase G1/genética , Genoma Humano/genética , Instabilidade Genômica/genética , Histonas , Humanos , Fosforilação , Transdução de Sinais/genética
6.
Dev Biol ; 515: 139-150, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39038593

RESUMO

Stem cell loss in aging and disease is associated with nuclear deformation. Yet, how nuclear shape influences stem cell homeostasis is poorly understood. We investigated this connection using Drosophila germline stem cells, as survival of these stem cells is compromised by dysfunction of the nuclear lamina, the extensive protein network that lines the inner nuclear membrane and gives shape to the nucleus. To induce nuclear distortion in germline stem cells, we used the GAL4-UAS system to increase expression of the permanently farnesylated nuclear lamina protein, Kugelkern, a rate limiting factor for nuclear growth. We show that elevated Kugelkern levels cause severe nuclear distortion in germline stem cells, including extensive thickening and lobulation of the nuclear envelope and nuclear lamina, as well as alteration of internal nuclear compartments. Despite these changes, germline stem cell number, proliferation, and female fertility are preserved, even as females age. Collectively, these data demonstrate that disruption of nuclear architecture does not cause a failure of germline stem cell survival or homeostasis, revealing that nuclear deformation does not invariably promote stem cell loss.


Assuntos
Proteínas de Drosophila , Drosophila melanogaster , Células Germinativas , Homeostase , Lâmina Nuclear , Células-Tronco , Animais , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Feminino , Células Germinativas/metabolismo , Drosophila melanogaster/metabolismo , Células-Tronco/metabolismo , Lâmina Nuclear/metabolismo , Núcleo Celular/metabolismo , Proliferação de Células , Drosophila/metabolismo , Membrana Nuclear/metabolismo
7.
Hum Mol Genet ; 32(1): 161-171, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36018815

RESUMO

Tuberculosis is a significant public health concern resulting in the death of over 1 million individuals each year worldwide. While treatment options and vaccines exist, a substantial number of infections still remain untreated or are caused by treatment resistant strains. Therefore, it is important to identify mechanisms that contribute to risk and prognosis of tuberculosis as this may provide tools to understand disease mechanisms and provide novel treatment options for those with severe infection. Our goal was to identify genetic risk factors that contribute to the risk of tuberculosis and to understand biological mechanisms and causality behind the risk of tuberculosis. A total of 1895 individuals in the FinnGen study had International Classification of Diseases-based tuberculosis diagnosis. Genome-wide association study analysis identified genetic variants with statistically significant association with tuberculosis at the human leukocyte antigen (HLA) region (P < 5e-8). Fine mapping of the HLA association provided evidence for one protective haplotype tagged by HLA DQB1*05:01 (P = 1.82E-06, OR = 0.81 [CI 95% 0.74-0.88]), and predisposing alleles tagged by HLA DRB1*13:02 (P = 0.00011, OR = 1.35 [CI 95% 1.16-1.57]). Furthermore, genetic correlation analysis showed association with earlier reported risk factors including smoking (P < 0.05). Mendelian randomization supported smoking as a risk factor for tuberculosis (inverse-variance weighted P < 0.05, OR = 1.83 [CI 95% 1.15-2.93]) with no significant evidence of pleiotropy. Our findings indicate that specific HLA alleles associate with the risk of tuberculosis. In addition, lifestyle risk factors such as smoking contribute to the risk of developing tuberculosis.


Assuntos
Predisposição Genética para Doença , Tuberculose , Humanos , Estudo de Associação Genômica Ampla , Tuberculose/genética , Cadeias beta de HLA-DQ/genética , Cadeias HLA-DRB1/genética , Haplótipos/genética , Fatores de Risco , Alelos , Frequência do Gene
8.
Mol Psychiatry ; 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39138355

RESUMO

Disordered eating and self-harm commonly co-occur in young people suggesting potential for shared underlying causes. Body image dissatisfaction (BID) has been recognised as a psychological correlate of body size, associated with both disordered eating and self-harm. However, the investigation into etiological pathways early in the lifecourse to provide detail on how body size and BID may foster disordered eating and self-harm remains largely unexplored. Employing data from two large population-based cohorts, the UK Biobank and the Avon Longitudinal Study of Parents And Children (ALSPAC), we conducted bidirectional Mendelian randomization (MR) to determine the causal direction of effect between genetically predicted prepubertal body size and two measures of BID indicating (i) desire to be smaller, and (ii) desire to be larger. We then used multivariable regression followed by counterfactual mediation analyses. Bidirectional MR indicated robust evidence that increased genetically predicted prepubertal body size increased desire to be smaller and decreased desire to be larger. Evidence for the reverse causal direction was negligible. These findings remained very similar across sensitivity analyses. In females and males, multivariable regression analyses demonstrated that being overweight increased the risk of disordered eating (risk ratio (RR), 95% confidence interval (CI): 1.19, 1.01 to 1.40 and 1.98, 1.28 to 3.05, respectively) and self-harm (RR, 95% CI: 1.35, 1.04 to 1.77 and 1.55, 0.86 to 2.81, respectively), while being underweight was protective against disordered eating (RR, 95% CI: 0.57, 0.40 to 0.81 and 0.81, 0.38 to 1.73, respectively). There was weak evidence of an increase in the risk of self-harm among underweight individuals. Mediation analyses indicated that the relationship between being overweight and subsequent disordered eating was largely mediated by the desire to be smaller. Our research carries important public health implications, suggesting distinct risk profiles for self-harm and disordered eating in relation to weight and body image. In addition, a better understanding of genetically predicted prepubertal BID may be valuable in the prevention and treatment of disordered eating and self-harm in adolescence.

9.
PLoS Genet ; 18(9): e1010356, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36137075

RESUMO

Rare variants in ten genes have been reported to cause Mendelian sleep conditions characterised by extreme sleep duration or timing. These include familial natural short sleep (ADRB1, DEC2/BHLHE41, GRM1 and NPSR1), advanced sleep phase (PER2, PER3, CRY2, CSNK1D and TIMELESS) and delayed sleep phase (CRY1). The association of variants in these genes with extreme sleep conditions were usually based on clinically ascertained families, and their effects when identified in the population are unknown. We aimed to determine the effects of these variants on sleep traits in large population-based cohorts. We performed genetic association analysis of variants previously reported to be causal for Mendelian sleep and circadian conditions. Analyses were performed using 191,929 individuals with data on sleep and whole-exome or genome-sequence data from 4 population-based studies: UK Biobank, FINRISK, Health-2000-2001, and the Multi-Ethnic Study of Atherosclerosis (MESA). We identified sleep disorders from self-report, hospital and primary care data. We estimated sleep duration and timing measures from self-report and accelerometery data. We identified carriers for 10 out of 12 previously reported pathogenic variants for 8 of the 10 genes. They ranged in frequency from 1 individual with the variant in CSNK1D to 1,574 individuals with a reported variant in the PER3 gene in the UK Biobank. No carriers for variants reported in NPSR1 or PER2 were identified. We found no association between variants analyzed and extreme sleep or circadian phenotypes. Using sleep timing as a proxy measure for sleep phase, only PER3 and CRY1 variants demonstrated association with earlier and later sleep timing, respectively; however, the magnitude of effect was smaller than previously reported (sleep midpoint ~7 mins earlier and ~5 mins later, respectively). We also performed burden tests of protein truncating (PTVs) or rare missense variants for the 10 genes. Only PTVs in PER2 and PER3 were associated with a relevant trait (for example, 64 individuals with a PTV in PER2 had an odds ratio of 4.4 for being "definitely a morning person", P = 4x10-8; and had a 57-minute earlier midpoint sleep, P = 5x10-7). Our results indicate that previously reported variants for Mendelian sleep and circadian conditions are often not highly penetrant when ascertained incidentally from the general population.


Assuntos
Ritmo Circadiano , Transtornos do Sono-Vigília , Ritmo Circadiano/genética , Humanos , Fenótipo , Receptores Acoplados a Proteínas G/genética , Sono/genética , Transtornos do Sono-Vigília/genética
10.
Proc Natl Acad Sci U S A ; 119(6)2022 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-35115399

RESUMO

The RecQ-like helicase BLM cooperates with topoisomerase IIIα, RMI1, and RMI2 in a heterotetrameric complex (the "Bloom syndrome complex") for dissolution of double Holliday junctions, key intermediates in homologous recombination. Mutations in any component of the Bloom syndrome complex can cause genome instability and a highly cancer-prone disorder called Bloom syndrome. Some heterozygous carriers are also predisposed to breast cancer. To understand how the activities of BLM helicase and topoisomerase IIIα are coupled, we purified the active four-subunit complex. Chemical cross-linking and mass spectrometry revealed a unique architecture that links the helicase and topoisomerase domains. Using biochemical experiments, we demonstrated dimerization mediated by the N terminus of BLM with a 2:2:2:2 stoichiometry within the Bloom syndrome complex. We identified mutations that independently abrogate dimerization or association of BLM with RMI1, and we show that both are dysfunctional for dissolution using in vitro assays and cause genome instability and synthetic lethal interactions with GEN1/MUS81 in cells. Truncated BLM can also inhibit the activity of full-length BLM in mixed dimers, suggesting a putative mechanism of dominant-negative action in carriers of BLM truncation alleles. Our results identify critical molecular determinants of Bloom syndrome complex assembly required for double Holliday junction dissolution and maintenance of genome stability.


Assuntos
Síndrome de Bloom/genética , DNA Cruciforme/genética , Instabilidade Genômica/genética , Alelos , Proteínas de Transporte/genética , Linhagem Celular , DNA Topoisomerases Tipo I/genética , Humanos , Mutação/genética , Ligação Proteica/genética , RecQ Helicases/genética , Recombinação Genética/genética , Solubilidade
11.
J Biol Chem ; 299(3): 102967, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36736429

RESUMO

High-resolution structures of voltage-gated sodium channels (Nav) were first obtained from a prokaryotic ortholog NavAb, which provided important mechanistic insights into Na+ selectivity and voltage gating. Unlike eukaryotic Navs, the NavAb channel is formed by four identical subunits, but its ion selectivity and pharmacological profiles are very similar to eukaryotic Navs. Recently, the structures of the NavAb voltage sensor at resting and activated states were obtained by cryo-EM, but its intermediate states and transition dynamics remain unclear. In the present work, we used liposome flux assays to show that purified NavAb proteins were functional to conduct both H+ and Na+ and were blocked by the local anesthetic lidocaine. Additionally, we examined the real-time conformational dynamics of the NavAb voltage sensor using single-molecule FRET. Our single-molecule FRET measurements on the tandem NavAb channel labeled with Cy3/5 FRET fluorophore pair revealed spontaneous transitions of the NavAb S4 segment among three conformational states, which fitted well with the kinetic model developed for the S4 segment of the human voltage-gated proton channel hHv1. Interestingly, even under strong activating voltage, the NavAb S4 segment seems to adopt a conformational distribution similar to that of the hHv1 S4 segment at a deep resting state. The conformational behaviors of the NavAb voltage sensor under different voltages need to be further examined to understand the mechanisms of voltage sensing and gating in the canonical voltage-gated ion channel superfamily.


Assuntos
Proteínas de Bactérias , Ativação do Canal Iônico , Canais de Sódio Disparados por Voltagem , Conformação Proteica , Canais de Sódio Disparados por Voltagem/metabolismo , Bactérias , Proteínas de Bactérias/metabolismo
12.
J Biol Chem ; 299(7): 104918, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37315791

RESUMO

Unlike other members of the voltage-gated ion channel superfamily, voltage-gated proton (Hv) channels are solely composed of voltage sensor domains without separate ion-conducting pores. Due to their unique dependence on both voltage and transmembrane pH gradients, Hv channels normally open to mediate proton efflux. Multiple cellular ligands were also found to regulate the function of Hv channels, including Zn2+, cholesterol, polyunsaturated arachidonic acid, and albumin. Our previous work showed that Zn2+ and cholesterol inhibit the human voltage-gated proton channel (hHv1) by stabilizing its S4 segment at resting state conformations. Released from phospholipids by phospholipase A2 in cells upon infection or injury, arachidonic acid regulates the function of many ion channels, including hHv1. In the present work, we examined the effects of arachidonic acid on purified hHv1 channels using liposome flux assays and revealed underlying structural mechanisms using single-molecule FRET. Our data indicated that arachidonic acid strongly activates hHv1 channels by promoting transitions of the S4 segment toward opening or "preopening" conformations. Moreover, we found that arachidonic acid even activates hHv1 channels inhibited by Zn2+ and cholesterol, providing a biophysical mechanism to activate hHv1 channels in nonexcitable cells upon infection or injury.


Assuntos
Ácido Araquidônico , Colesterol , Ativação do Canal Iônico , Canais Iônicos , Prótons , Zinco , Humanos , Albuminas/farmacologia , Ácido Araquidônico/farmacologia , Colesterol/farmacologia , Transferência Ressonante de Energia de Fluorescência , Ativação do Canal Iônico/efeitos dos fármacos , Canais Iônicos/agonistas , Canais Iônicos/antagonistas & inibidores , Canais Iônicos/química , Canais Iônicos/metabolismo , Lipossomos/metabolismo , Fosfolipases A2/metabolismo , Imagem Individual de Molécula , Zinco/farmacologia , Concentração de Íons de Hidrogênio
13.
BMC Genomics ; 25(1): 256, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38454350

RESUMO

BACKGROUND: Congenital heart defects (CHD) are structural defects of the heart affecting approximately 1% of newborns. They exhibit low penetrance and non-Mendelian patterns of inheritance as varied and complex traits. While genetic factors are known to play an important role in the development of CHD, the specific genetics remain unknown for the majority of patients. To elucidate the underlying genetic risk, we performed a genome wide association study (GWAS) of CHDs in general and specific CHD subgroups using the FinnGen Release 10 (R10) (N > 393,000), followed by functional fine-mapping through eQTL and co-localization analyses using the GTEx database. RESULTS: We discovered three genome-wide significant loci associated with general CHD. Two of them were located in chromosome 17: 17q21.32 (rs2316327, intronic: LRRC37A2, Odds ratio (OR) [95% Confidence Interval (CI)] = 1.17[1.12-1.23], p = 1.5 × 10-9) and 17q25.3 (rs1293973611, nearest: BAHCC1, OR[95%CI] = 4.48[2.80-7.17], p = 7.0 × 10-10), respectively, and in addition to general CHD, the rs1293973611 locus was associated with the septal defect subtype. The third locus was in band 1p21.2 (rs35046143, nearest: PALMD, OR[95%CI] = 1.15[1.09-1.21], p = 7.1 × 10-9), and it was associated with general CHD and left-sided lesions. In the subgroup analysis, two additional loci were associated with septal defects (rs75230966 and rs6824295), and one with left-sided lesions (rs1305393195). In the eQTL analysis the variants rs2316327 (general CHD), and rs75230966 (septal defects) both located in 17q21.32 (with a LD r2 of 0.41) were both predicted to significantly associate with the expression of WNT9B in the atrial appendage tissue category. This effect was further confirmed by co-localization analysis, which also implicated WNT3 expression in the atrial appendage. A meta-analysis of general CHD together with the UK Biobank (combined N = 881,678) provided a different genome-wide significant locus in LRRC37A2; rs16941382 (OR[95%CI] = 1.15[1.11-1.20], p = 1.5 × 10-9) which is in significant LD with rs2316327. CONCLUSIONS: Our results of general CHD and different CHD subcategories identified a complex risk locus on chromosome 17 near BAHCC1 and LRRC37A2, interacting with the genes WNT9B, WNT3 and MYL4, may constitute potential novel CHD risk associated loci, warranting future experimental tests to determine their role.


Assuntos
Estudo de Associação Genômica Ampla , Cardiopatias Congênitas , Humanos , Recém-Nascido , Predisposição Genética para Doença , Cardiopatias Congênitas/genética , Fatores de Risco , Bases de Dados Genéticas
14.
Biomacromolecules ; 25(8): 4925-4933, 2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-39040021

RESUMO

Viruses are a considerable threat to global health and place major burdens on economies worldwide. Manufactured viruses are also being widely used as delivery agents to treat (gene therapies) or prevent diseases (vaccines). Therefore, it is vital to study and fully understand the infectious state of viruses. Current techniques used to study viruses are often slow or nonexistent, making the development of new techniques of paramount importance. Here we present a high-throughput and robust, cell-free plate-based assay (FAIRY: Fluorescence Assay for vIRal IntegritY), capable of differentiating intact from nonintact enveloped viruses, i.e, infectious from noninfectious. Using a thiazole orange-terminated polymer, a 99% increase in fluorescence was observed between treated (heat or virucide) and nontreated. The FAIRY assay allowed for the rapid determination of the infectivity of a range of enveloped viruses, highlighting its potential as a valuable tool for the study of viruses and interventions against them.


Assuntos
Ensaios de Triagem em Larga Escala , Ensaios de Triagem em Larga Escala/métodos , Benzotiazóis/química , Fluorescência , Vírus/isolamento & purificação , Quinolinas/química , Humanos , Corantes Fluorescentes/química
15.
Biomacromolecules ; 25(3): 1629-1636, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38361251

RESUMO

There is a high demand for rapid, sensitive, and accurate detection methods for pathogens. This paper demonstrates a method of detecting the presence of amplified DNA from a range of pathogens associated with serious infections including Gram-negative bacteria, Gram-positive bacteria, and viruses. DNA is amplified using a polymerase chain reaction (PCR) and consequently detected using a sterically stabilized, cationic polymer latex. The DNA induces flocculation of this cationic latex, which consequently leads to rapid sedimentation and a visible change from a milky-white dispersion to one with a transparent supernatant, presenting a clear visible change, indicating the presence of amplified DNA. Specifically, a number of different pathogens were amplified using conventional or qPCR, including Staphylococcus aureus, Escherichia coli, and Herpes Simplex Virus (HSV-2). This method was demonstrated to detect the presence of bacteria in suspension concentrations greater than 380 CFU mL-1 and diagnose the presence of specific genomes through primer selection, as exemplified using methicillin resistant and methicillin susceptible Staphylococcus aureus. The versatility of this methodology was further demonstrated by showing that false positive results do not occur when a PCR of fungal DNA from C. albicans is conducted using bacterial universal primers.


Assuntos
Técnicas Biossensoriais , Látex , Floculação , DNA/genética , Staphylococcus aureus/genética , Reação em Cadeia da Polimerase/métodos , DNA Bacteriano/genética , Sensibilidade e Especificidade
16.
Dev Sci ; 27(4): e13492, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38553823

RESUMO

This paper presents rational inattention as a new, transdiagnostic theory of information seeking in neurodevelopmental conditions that have uneven cognitive and socio-emotional profiles, including developmental language disorder (DLD), dyslexia, dyscalculia and autism. Rational inattention holds that the optimal solution to minimizing epistemic uncertainty is to avoid imprecise information sources. The key theoretical contribution of this report is to endogenize imprecision, making it a function of the primary neurocognitive difficulties that have been invoked to explain neurodivergent phenotypes, including deficits in auditory perception, working memory, procedural learning and the social brain network. We argue that disengagement with information sources with low endogenous precision (e.g. speech in DLD, orthography-phonology mappings in dyslexia, numeric stimuli in dyscalculia and social signals in autism) constitutes resource-rational behaviour. We demonstrate the strength of this account in a series of computational simulations. In experiment 1, we simulate information seeking in artificial agents mimicking an array of neurodivergent phenotypes, which optimally explore a complex learning environment containing speech, text, numeric stimuli and social cues. In experiment 2, we simulate optimal information seeking in a cross-modal dual-task paradigm and qualitatively replicate empirical data from children with and without DLD. Across experiments, simulated agents' only aim was to maximally reduce epistemic uncertainty, with no difference in reward across information sources. We show that rational inattention emerges naturally in specific neurodivergent phenotypes as a function of low endogenous precision. For instance, an agent mimicking the DLD phenotype disengages with speech (and preferentially engages with alternative precise information sources) because endogenous imprecision renders speech not conducive to information gain. Because engagement is necessary for learning, simulation demonstrates how optimal information seeking may paradoxically contribute negatively to an already delayed learning trajectory in neurodivergent children. RESEARCH HIGHLIGHTS: We present the first comprehensive theory of information seeking in neurodivergent children to date, centred on the notion of rational inattention. We demonstrate the strength of this account in a series of computational simulations involving artificial agents mimicking specific neurodivergent phenotypes that optimally explore a complex learning environment containing speech, text, numeric stimuli, and social cues. We show how optimal information seeking may, paradoxically, contribute negatively to an already delayed learning trajectory in neurodivergent children. This report advances our understanding of the factors shaping short-term decision making and long-term learning in neurodivergent children.


Assuntos
Atenção , Humanos , Atenção/fisiologia , Comportamento de Busca de Informação/fisiologia , Aprendizagem/fisiologia , Transtornos do Desenvolvimento da Linguagem/fisiopatologia , Simulação por Computador , Cognição/fisiologia
17.
Adv Exp Med Biol ; 1437: 59-76, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38270853

RESUMO

Multisensory perception is critical for effective interaction with the environment, but human responses to multisensory stimuli vary across the lifespan and appear changed in some atypical populations. In this review chapter, we consider multisensory integration within a normative Bayesian framework. We begin by outlining the complex computational challenges of multisensory causal inference and reliability-weighted cue integration, and discuss whether healthy young adults behave in accordance with normative Bayesian models. We then compare their behaviour with various other human populations (children, older adults, and those with neurological or neuropsychiatric disorders). In particular, we consider whether the differences seen in these groups are due only to changes in their computational parameters (such as sensory noise or perceptual priors), or whether the fundamental computational principles (such as reliability weighting) underlying multisensory perception may also be altered. We conclude by arguing that future research should aim explicitly to differentiate between these possibilities.


Assuntos
Nível de Saúde , Longevidade , Criança , Adulto Jovem , Humanos , Idoso , Teorema de Bayes , Reprodutibilidade dos Testes , Causalidade
18.
J Sleep Res ; : e13973, 2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37380357

RESUMO

Little is known regarding the shared genetic influences underlying the observed phenotypic association between chronotype and breast cancer in women. Leveraging summary statistics from the hitherto largest genome-wide association study conducted in each trait, we investigated the genetic correlation, pleiotropic loci, and causal relationship of chronotype with overall breast cancer, and with its subtypes defined by the status of oestrogen receptor. We identified a negative genomic correlation between chronotype and overall breast cancer ( r g $$ {r}_g $$ = -0.06, p = 3.00 × 10-4 ), consistent across oestrogen receptor-positive ( r g $$ {r}_g $$ = -0.05, p = 3.30 × 10-3 ) and oestrogen receptor-negative subtypes ( r g $$ {r}_g $$ = -0.05, p = 1.11 × 10-2 ). Five specific genomic regions were further identified as contributing a significant local genetic correlation. Cross-trait meta-analysis identified 78 loci shared between chronotype and breast cancer, of which 23 were novel. Transcriptome-wide association study revealed 13 shared genes, targeting tissues of the nervous, cardiovascular, digestive, and exocrine/endocrine systems. Mendelian randomisation demonstrated a significantly reduced risk of overall breast cancer (odds ratio 0.89, 95% confidence interval 0.83-0.94; p = 1.30 × 10-4 ) for genetically predicted morning chronotype. No reverse causality was found. Our work demonstrates an intrinsic link underlying chronotype and breast cancer, which may provide clues to inform management of sleep habits to improve female health.

19.
Eur J Neurol ; 30(7): 1854-1860, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36940265

RESUMO

BACKGROUND AND PURPOSE: Real-time quaking-induced conversion (RT-QuIC) assays offer a sensitive and specific means for detection of prions, although false negative results are recognized in clinical practice. We profile the clinical, laboratory, and pathologic features associated with false negative RT-QuIC assays and extend these to frame the diagnostic approach to patients with suspected prion disease. METHODS: A total of 113 patients with probable or definite prion disease were assessed at Mayo Clinic (Rochester, MN; Jacksonville, FL; Scottsdale, AZ) or Washington University School of Medicine (Saint Louis, MO) from 2013 to 2021. RT-QuIC testing for prions was performed in cerebrospinal fluid (CSF) at the National Prion Disease Pathology Surveillance Center (Cleveland, OH). RESULTS: Initial RT-QuIC testing was negative in 13 of 113 patients (sensitivity = 88.5%). RT-QuIC negative patients were younger (median = 52.0 years vs. 66.1 years, p < 0.001). Other demographic and presenting features, and CSF cell count, protein, and glucose levels were similar in RT-QuIC negative and positive patients. Frequency of 14-3-3 positivity (4/13 vs. 77/94, p < 0.001) and median CSF total tau levels were lower in RT-QuIC negative patients (2517 vs. 4001 pg/mL, p = 0.020), and time from symptom onset to first presentation (153 vs. 47 days, p = 0.001) and symptomatic duration (710 vs. 148 days, p = 0.001) were longer. CONCLUSIONS: RT-QuIC is a sensitive yet imperfect measure necessitating incorporation of other test results when evaluating patients with suspected prion disease. Patients with negative RT-QuIC had lower markers of neuronal damage (CSF total tau and protein 14-3-3) and longer symptomatic duration of disease, suggesting that false negative RT-QuIC testing associates with a more indolent course.


Assuntos
Síndrome de Creutzfeldt-Jakob , Doenças Priônicas , Príons , Humanos , Príons/líquido cefalorraquidiano , Síndrome de Creutzfeldt-Jakob/diagnóstico , Sensibilidade e Especificidade , Doenças Priônicas/diagnóstico , Proteínas 14-3-3
20.
Brain ; 145(12): 4409-4424, 2022 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-35793238

RESUMO

Huntington disease is caused by a CAG repeat expansion in exon 1 of the huntingtin gene (HTT) that is translated into a polyglutamine stretch in the huntingtin protein (HTT). We previously showed that HTT mRNA carrying an expanded CAG repeat was incompletely spliced to generate HTT1a, an exon 1 only transcript, which was translated to produce the highly aggregation-prone and pathogenic exon 1 HTT protein. This occurred in all knock-in mouse models of Huntington's disease and could be detected in patient cell lines and post-mortem brains. To extend these findings to a model system expressing human HTT, we took advantage of YAC128 mice that are transgenic for a yeast artificial chromosome carrying human HTT with an expanded CAG repeat. We discovered that the HTT1a transcript could be detected throughout the brains of YAC128 mice. We implemented RNAscope to visualize HTT transcripts at the single molecule level and found that full-length HTT and HTT1a were retained together in large nuclear RNA clusters, as well as being present as single transcripts in the cytoplasm. Homogeneous time-resolved fluorescence analysis demonstrated that the HTT1a transcript had been translated to produce the exon 1 HTT protein. The levels of exon 1 HTT in YAC128 mice, correlated with HTT aggregation, supportive of the hypothesis that exon 1 HTT initiates the aggregation process. Huntingtin-lowering strategies are a major focus of therapeutic development for Huntington's disease. These approaches often target full-length HTT alone and would not be expected to reduce pathogenic exon 1 HTT levels. We have established YAC128 mouse embryonic fibroblast lines and shown that, together with our QuantiGene multiplex assay, these provide an effective screening tool for agents that target HTT transcripts. The effects of current targeting strategies on nuclear RNA clusters are unknown, structures that may have a pathogenic role or alternatively could be protective by retaining HTT1a in the nucleus and preventing it from being translated. In light of recently halted antisense oligonucleotide trials, it is vital that agents targeting HTT1a are developed, and that the effects of HTT-lowering strategies on the subcellular levels of all HTT transcripts and their various HTT protein isoforms are understood.


Assuntos
Doença de Huntington , Humanos , Camundongos , Animais , Doença de Huntington/genética , Proteína Huntingtina/genética , RNA Mensageiro/metabolismo , Fibroblastos/metabolismo , RNA Nuclear , Modelos Animais de Doenças
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