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1.
South Med J ; 114(12): 807-811, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34853859

RESUMO

OBJECTIVES: Numerous studies have demonstrated the high risk for burnout and mental illness in medical students. Because of the coronavirus disease 2019 (COVID-19) pandemic, our medical school transitioned to an all-virtual learning environment from March to June 2020, which raised concerns among student leaders and administrators, as reduced interpersonal attachments have known associations with decreased mental health. In an effort to facilitate student well-being during the pandemic, the Virtual Wellness and Learning Communities (VWLC) program was established. VWLC consisted of hour-long events that offered students the opportunity to engage with their peers online. METHODS: More than 20 events and workshops were conducted from March to June 2020, including trivia nights, song and guitar performances, sketching, video editing tutorials, chess lessons, yoga, and personal investing tips. An institutional review board-approved survey to assess the efficacy of the VWLC program was sent to medical student participants and nonparticipants. RESULTS: The overall response rate of this study was 43% (53/123). The response rate for students who attended a VWLC event was 51% (33/65), and the response rate for students who did not attend a VWLC event was 34% (20/58). Of all of the respondents, 85% (45/53) reported a decreased sense of connectivity with peers because of the pandemic, and 40% (21/53) reported a decrease in their sense of wellness. After attending a VWLC event, 79% (26/33) reported an increased sense of peer connectivity, 61% (20/33) reported improved wellness, and 55% (18/33) believed that these events should continue postpandemic to supplement in-person programming. Those who did not attend a virtual event stated that the main barriers to attending were unfamiliarity with attendees and screen fatigue. CONCLUSIONS: The COVID-19 pandemic has worsened medical student well-being and sense of community. VWLC programming may be an effective strategy for promoting medical student wellness and community while social distancing during the COVID-19 pandemic. To our knowledge, this is the first virtual wellness program for promotion of medical student mental health during the COVID-19 pandemic to be described in the literature.


Assuntos
COVID-19/epidemiologia , Instrução por Computador , Educação de Graduação em Medicina/organização & administração , Estudantes de Medicina/psicologia , Adulto , Currículo , Feminino , Humanos , Masculino , Pandemias , SARS-CoV-2
2.
J Parkinsons Dis ; 11(4): 1821-1832, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34366375

RESUMO

BACKGROUND: Gastrointestinal (GI) complications, that severely impact patient quality of life, are a common occurrence in patients with Parkinson's disease (PD). Damage to enteric neurons and the accumulation of alpha-synuclein in the enteric nervous system (ENS) are thought to contribute to this phenotype. Copper or iron chelators, that bind excess or labile metal ions, can prevent aggregation of alpha-synuclein in the brain and alleviate motor-symptoms in preclinical models of PD. OBJECTIVE: We investigated the effect of ATH434 (formally PBT434), a small molecule, orally bioavailable, moderate-affinity iron chelator, on colonic propulsion and whole gut transit in A53T alpha-synuclein transgenic mice. METHODS: Mice were fed ATH434 (30 mg/kg/day) for either 4 months (beginning at ∼15 months of age), after the onset of slowed propulsion ("treatment group"), or for 3 months (beginning at ∼12 months of age), prior to slowed propulsion ("prevention group"). RESULTS: ATH434, given after dysfunction was established, resulted in a reversal of slowed colonic propulsion and gut transit deficits in A53T mice to WT levels. In addition, ATH434 administered from 12 months prevented the slowed bead expulsion at 15 months but did not alter deficits in gut transit time when compared to vehicle-treated A53T mice. The proportion of neurons with nuclear Hu+ translocation, an indicator of neuronal stress in the ENS, was significantly greater in A53T than WT mice, and was reduced in both groups when ATH434 was administered. CONCLUSION: ATH434 can reverse some of the GI deficits and enteric neuropathy that occur in a mouse model of PD, and thus may have potential clinical benefit in alleviating the GI dysfunctions associated with PD.


Assuntos
Gastroenteropatias , Doença de Parkinson , alfa-Sinucleína , Animais , Modelos Animais de Doenças , Gastroenteropatias/etiologia , Gastroenteropatias/prevenção & controle , Camundongos , Camundongos Transgênicos , Doença de Parkinson/complicações , Doença de Parkinson/tratamento farmacológico , alfa-Sinucleína/genética
3.
Nutrients ; 13(8)2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34444967

RESUMO

Obesity is widespread, with serious health consequences; addressing it requires considerable effort at a public health level, incorporating prevention and management along with policies to support implementation. Behavioural weight-management programmes are widely used by public health bodies to address overweight and obesity. Shape-Up is an evidence-based programme combining a structured behavioural intervention (targeting nutrition and physical activity behaviours) within a peer-learning framework. This study was a service-evaluation of Shape-Up, as delivered in Rotherham by a local leisure provider, and included a secondary analysis of data collected in the community by service providers. The RE-AIM (Reach Effectiveness Adoption Implementation Maintenance) framework was used to explore programme effectiveness, implementation, and whom it reached. A total of 141 participants were included. Compared to local demographics, participants were older, at 48.9 (SD 14.47) years, with a lower employment rate (41% employed) and greater proportion female (67% female). Mean BMI was 38.0 (SD 7.54) kg/m2. Mean weight-change between baseline and endpoint (12 weeks, 10 group sessions) was -4.4 (SD 3.38) kg, and degree of weight change was associated with session attendance (F (9, 131) = 6.356, p < 0.0005). There were positive effects on participants' weight, health-related behaviours, and quality of life. The intervention content (including the focus of nutritional recommendations) and structure were adapted during implementation to better suit national guidelines and local population needs. RE-AIM was found to be a useful framework for evaluating and adapting an existing evidence-based weight management programme in line with local population needs. This could be a more cost-effective approach, compared to developing new programmes, for delivering public health goals relating to obesity, nutrition, and physical activity.


Assuntos
Terapia Cognitivo-Comportamental/métodos , Comportamentos Relacionados com a Saúde/fisiologia , Promoção da Saúde/métodos , Adulto , Peso Corporal/fisiologia , Exercício Físico/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Saúde Pública
4.
Commun Biol ; 4(1): 411, 2021 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-33767334

RESUMO

Prion diseases are distinguished by long pre-clinical incubation periods during which prions actively propagate in the brain and cause neurodegeneration. In the pre-clinical stage, we hypothesize that upon prion infection, transcriptional changes occur that can lead to early neurodegeneration. A longitudinal analysis of miRNAs in pre-clinical and clinical forms of murine prion disease demonstrated dynamic expression changes during disease progression in the affected thalamus region and serum. Serum samples at each timepoint were collected whereby extracellular vesicles (EVs) were isolated and used to identify blood-based biomarkers reflective of pathology in the brain. Differentially expressed EV miRNAs were validated in human clinical samples from patients with human sporadic Creutzfeldt-Jakob disease (sCJD), with the molecular subtype at codon 129 either methionine-methionine (MM, n = 14) or valine-valine (VV, n = 12) compared to controls (n = 20). EV miRNA biomarkers associated with prion infection predicted sCJD with an AUC of 0.800 (85% sensitivity and 66.7% specificity) in a second independent validation cohort (n = 26) of sCJD and control patients with MM or VV subtype. This study discovered clinically relevant miRNAs that benefit diagnostic development to detect prion-related diseases and therapeutic development to inhibit prion infectivity.


Assuntos
Encéfalo/patologia , MicroRNAs/análise , Doenças Priônicas/etiologia , Idoso , Idoso de 80 Anos ou mais , Animais , Biomarcadores/sangue , Síndrome de Creutzfeldt-Jakob/sangue , Síndrome de Creutzfeldt-Jakob/etiologia , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , MicroRNAs/sangue , Pessoa de Meia-Idade , Doenças Priônicas/sangue
5.
J Abnorm Psychol ; 130(1): 9-25, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33271039

RESUMO

Exposure to adverse childhood experiences (ACEs) is prevalent and confers risk for psychopathology later in life. Approaches to understanding the impact of ACEs on development include the independent risk approach, the Dimensional Model of Adversity and Psychopathology (DMAP) distinguishing between threat and deprivation events, and the cumulative risk approach. The present research provides an empirical confirmation of DMAP and a comparison of these three approaches in predicting internalizing and externalizing symptoms in youth. In Study 1, mental health professionals (N = 57) rated ACEs as threat or deprivation events. These ratings were used to create composites to represent the DMAP approach in Study 2. With cross-sectional and longitudinal data from children and adolescents in state custody (N = 23,850), hierarchical linear regression analyses examined independent risk, DMAP, and cumulative risk models in predicting internalizing symptoms, disinhibited externalizing symptoms, and antagonistic externalizing symptoms. All three approaches produced significant models and revealed associations between exposure to ACEs and symptoms. Individual risk accounted for significantly more variance in symptoms than cumulative risk and DMAP. Cumulative risk masked differential associations between ACEs and psychological symptoms found in the individual risk and DMAP approaches. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Assuntos
Comportamento do Adolescente/psicologia , Experiências Adversas da Infância/psicologia , Experiências Adversas da Infância/estatística & dados numéricos , Comportamento Infantil/psicologia , Transtornos Mentais/psicologia , Adolescente , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Estudos Longitudinais , Masculino , Risco , Sudeste dos Estados Unidos
6.
J Extracell Vesicles ; 10(2): e12034, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33318779

RESUMO

The misfolding and fibrillization of the protein, α-synuclein (αsyn), is associated with neurodegenerative disorders referred to as the synucleinopathies. Understanding the mechanisms of αsyn misfolding is an important area of interest given that αsyn misfolding contributes to disease pathogenesis. While many studies report the ability of synthetic lipid membranes to modulate αsyn folding, there is little data pertaining to the mechanism(s) of this interaction. αSyn has previously been shown to associate with small lipid vesicles released by cells called extracellular vesicles (EVs) and it is postulated these interactions may assist in the spreading of pathological forms of this protein. Together, this presents the need for robust characterisation studies on αsyn fibrillization using biologically-derived vesicles. In this study, we comprehensively characterised the ability of lipid-rich small extracellular vesicles (sEVs) to alter the misfolding of αsyn induced using the Protein Misfolding Cyclic Amplification (PMCA) assay. The biochemical and biophysical properties of misfolded αsyn were examined using a range of techniques including: Thioflavin T fluorescence, transmission electron microscopy, analytical centrifugation and western immunoblot coupled with protease resistance assays and soluble/insoluble fractionation. We show that sEVs cause an acceleration in αsyn fibrillization and provide comprehensive evidence that this results in an increase in the abundance of mature insoluble fibrillar species. In order to elucidate the relevance of the lipid membrane to this interaction, sEV lipid membranes were modified by treatment with methanol, or a combination of methanol and sarkosyl. These treatments altered the ultrastructure of the sEVs without changing the protein cargo. Critically, these modified sEVs had a reduced ability to influence αsyn fibrillization compared to untreated counterparts. This study reports the first comprehensive examination of αsyn:EV interactions and demonstrates that sEVs are powerful modulators of αsyn fibrillization, which is mediated by the sEV membrane. In doing so, this work provides strong evidence for a role of sEVs in contributing directly to αsyn misfolding in the synucleinopathy disorders.


Assuntos
Membrana Celular/metabolismo , Vesículas Extracelulares/metabolismo , Dobramento de Proteína , Multimerização Proteica , alfa-Sinucleína/metabolismo , Membrana Celular/química , Vesículas Extracelulares/química , Humanos , Conformação Proteica , alfa-Sinucleína/química
7.
Brain Commun ; 2(2): fcaa029, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32954317

RESUMO

Astrocytes are glial cells of the central nervous system that become reactive under conditions of stress. The functional properties of reactive astrocytes depend on their stimulus that induces the upregulation of specific genes. Reactive astrocytes are a neuropathological feature of prion disorders; however, their role in the disease pathogenesis is not well understood. Here, we describe our studies of one polarization state of reactive astrocytes, termed A1 astrocytes, in the frontal cortex region of 35 human sporadic Creutzfeldt-Jakob disease brains encompassing a range of molecular sub-types. Examination of two mRNA markers of A1 astrocytes, C3 and GBP2, revealed a strong linear correlation between the two following their log-normalization (P = 0.0011). Both markers were found upregulated in the sporadic Creutzfeldt-Jakob disease brain compared with age-matched control tissues (P = 0.0029 and 0.0002, for C3log and GBP2log, respectively), and stratifying samples based on codon 129 genotype revealed that C3log is highest in homozygous methionine and lowest in homozygous valine patients, which followed a linear trend (P = 0.027). Upon assessing other disease parameters, a significant positive correlation was found between GBP2log and disease duration (P = 0.031). These findings provide evidence for a divergence in the astrocytic environment amongst patients with sporadic Creutzfeldt-Jakob disease based on molecular sub-type parameters of disease. While more research will be needed to determine the global changes in the genomic profiles and resulting functional properties of reactive astrocytes in disease, considering the evidence demonstrating that A1 astrocytes harbour neurotoxic properties, the changes seen in C3log and GBP2log in the current study may reflect differences in pathogenic mechanisms amongst the sporadic Creutzfeldt-Jakob disease sub-types associated with the A1 polarization state.

8.
Prog Mol Biol Transl Sci ; 175: 121-145, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32958230

RESUMO

Transmissible spongiform encephalopathies or prion diseases describe a number of different human disorders that differ in their clinical phenotypes, which are nonetheless united by their transmissible nature and common pathology. Clinical variation in the absence of a conventional infectious agent is believed to be encoded by different conformations of the misfolded prion protein. This misfolded protein is the target of methods designed to prevent disease transmission in a surgical setting and reduction of the misfolded seed or preventing its continued propagation have been the focus of therapeutic strategies. It is therefore possible that strain variation may influence the efficacy of prevention and treatment approaches. Historically, an understanding of prion disease transmission and pathogenesis has been focused on research tools developed using agriculturally relevant strains of prion disease. However, an increased understanding of the molecular biology of human prion disorders has highlighted differences not only between different forms of the disease affecting humans and animals but also within diseases such as Creutzfeldt-Jakob Disease (CJD), which is represented by several sporadic CJD specific conformations and an additional conformation associated with variant CJD. In this chapter we will discuss whether prion strain variation can affect the efficacy of methods used to decontaminate prions and whether strain variation in pre-clinical models of prion disease can be used to identify therapeutic strategies that have the best possible chance of success in the clinic.


Assuntos
Doenças Priônicas/prevenção & controle , Doenças Priônicas/terapia , Príons/metabolismo , Humanos , Doenças Priônicas/transmissão
9.
Biophys J ; 119(1): 128-141, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32562618

RESUMO

Prion diseases are neurodegenerative disorders pathogenically linked to cellular prion protein (PrPC) misfolding into abnormal conformers (PrPSc), with PrPSc underpinning both transmission and synaptotoxicity. Although the biophysical features of PrPSc required to induce acute synaptic dysfunction remain incompletely defined, we recently reported that acutely synaptotoxic PrPSc appeared to be oligomeric. We herein provide further insights into the kinetic and requisite biophysical characteristics of acutely synaptotoxic ex vivo PrPSc derived from the brains of mice dying from M1000 prion disease. Pooled fractions of M1000 PrPSc located within the molecular weight range approximating monomeric PrP (mM1000) generated through size exclusion chromatography were found to harbor acute synaptotoxicity equivalent to preformed oligomeric fractions (oM1000). Subsequent investigation showed mM1000 corresponded to PrPSc rapidly concatenating in physiological buffer to exist as predominantly, closely associated, small oligomers. The oligomerization of PrP in mM1000 could be substantially mitigated by treatment with the antiaggregation compound epigallocatechin gallate, thereby maintaining the PrPSc as primarily nonoligomeric with completely abrogated acute synaptotoxicity; moreover, despite epigallocatechin gallate treatment, pooled oM1000 remained oligomeric and acutely synaptotoxic. A similar tendency to rapid formation of oligomers was observed for PrPC when monomeric fractions derived from size exclusion chromatography of normal brain homogenates (mNBH) were pooled, but neither mNBH nor preformed higher-order NBH complexes (oNBH) were acutely synaptotoxic. Oligomers formed from mNBH could be reduced to mainly monomers (<100 kDa) after enzymatic digestion of nucleic acids, whereas higher-order PrP assemblies derived from pooled mM1000, oM1000, and oNBH resisted such treatment. Collectively, these findings support that oligomerization of PrPSc into small multimeric assemblies appears to be a critical biophysical feature for engendering inherent acute synaptotoxicity, with preformed oligomers found in oM1000 appearing to be stable, tightly self-associated ensembles that coexist in dynamic equilibrium with mM1000, with the latter appearing capable of rapid aggregation, albeit initially forming smaller, weakly self-associated, acutely synaptotoxic oligomers.


Assuntos
Proteínas PrPC , Doenças Priônicas , Príons , Animais , Encéfalo/metabolismo , Camundongos
13.
Dis Model Mech ; 13(1)2020 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-31848207

RESUMO

The misfolding and aggregation of the largely disordered protein, α-synuclein, is a central pathogenic event that occurs in the synucleinopathies, a group of neurodegenerative disorders that includes Parkinson's disease. While there is a clear link between protein misfolding and neuronal vulnerability, the precise pathogenic mechanisms employed by disease-associated α-synuclein are unresolved. Here, we studied the pathogenicity of misfolded α-synuclein produced using the protein misfolding cyclic amplification (PMCA) assay. To do this, previous published methods were adapted to allow PMCA-induced protein fibrillization to occur under non-toxic conditions. Insight into potential intracellular targets of misfolded α-synuclein was obtained using an unbiased lipid screen of 15 biologically relevant lipids that identified cardiolipin (CA) as a potential binding partner for PMCA-generated misfolded α-synuclein. To investigate whether such an interaction can impact the properties of α-synuclein misfolding, protein fibrillization was carried out in the presence of the lipid. We show that CA both accelerates the rate of α-synuclein fibrillization and produces species that harbour enhanced resistance to proteolysis. Because CA is virtually exclusively expressed in the inner mitochondrial membrane, we then assessed the ability of these misfolded species to alter mitochondrial respiration in live non-transgenic SH-SY5Y neuroblastoma cells. Extensive analysis revealed that misfolded α-synuclein causes hyperactive mitochondrial respiration without causing any functional deficit. These data give strong support for the mitochondrion as a target for misfolded α-synuclein and reveal persistent, hyperactive respiration as a potential upstream pathogenic event associated with the synucleinopathies.This article has an associated First Person interview with the first author of the paper.


Assuntos
Mitocôndrias/metabolismo , Neuroblastoma/metabolismo , Dobramento de Proteína , alfa-Sinucleína/química , Cardiolipinas/química , Linhagem Celular Tumoral , Respiração Celular , Sobrevivência Celular , Glicólise , Humanos , Neuroblastoma/patologia
14.
Neurogastroenterol Motil ; 32(3): e13755, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31709672

RESUMO

BACKGROUND: Chronic stress exacerbates motor deficits and increases dopaminergic cell loss in several rodent models of Parkinson's disease (PD). However, little is known about effects of stress on gastrointestinal (GI) dysfunction, a common non-motor symptom of PD. We aimed to determine whether chronic stress exacerbates GI dysfunction in the A53T mouse model of PD and whether this relates to changes in α-synuclein distribution. METHODS: Chronic isolation stress was induced by single-housing WT and homozygote A53T mice between 5 and 15 months of age. GI and motor function were compared with mice that had been group-housed. KEY RESULTS: Chronic isolation stress increased plasma corticosterone and exacerbated deficits in colonic propulsion and whole-gut transit in A53T mice and also increased motor deficits. However, our results indicated that the novel environment-induced defecation response, a common method used to evaluate colorectal function, was not a useful test to measure exacerbation of GI dysfunction, most likely because of the reported reduced level of anxiety in A53T mice. A53T mice had lower corticosterone levels than WT mice under both housing conditions, but single-housing increased levels for both genotypes. Enteric neuropathy was observed in aging A53T mice and A53T mice had a greater accumulation of alpha-synuclein (αsyn) in myenteric ganglia under both housing conditions. CONCLUSIONS & INFERENCES: Chronic isolation stress exacerbates PD-associated GI dysfunction, in addition to increasing motor deficits. However, these changes in GI symptoms are not directly related to corticosterone levels, worsened enteric neuropathy, or enteric αsyn accumulation.


Assuntos
Sistema Nervoso Entérico/patologia , Motilidade Gastrointestinal/fisiologia , Transtornos Parkinsonianos/patologia , Transtornos Parkinsonianos/psicologia , Estresse Psicológico/complicações , Animais , Sistema Nervoso Entérico/fisiopatologia , Camundongos , Camundongos Transgênicos , Transtornos Parkinsonianos/fisiopatologia , Isolamento Social/psicologia
15.
Sci Rep ; 9(1): 11034, 2019 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-31363141

RESUMO

Periodontitis is an economically important disease which is highly prevalent worldwide. Current diagnostic approaches are time-consuming and require interpretation of multiple aspects of clinical and radiographic assessment. Chair-side monitoring of inflammatory mediators of periodontitis could provide immediate information about disease activity, which can inform patient management. We aimed to develop a novel prototype biosensor to measure salivary matrix metalloproteinase-8 (MMP-8) using specific antibodies and surface acoustic wave (SAW) technology. The analytical performance of the prototype biosensor was compared to standard enzyme-linked immunosorbent assay (ELISA) using unstimulated saliva samples obtained from patients with periodontitis before and after non-surgical treatment (N = 58), patients with gingivitis (N = 54) and periodontally healthy volunteers (N = 65). Receiver operator characteristic (ROC) analysis for distinguishing periodontitis from health revealed an almost identical performance between the sensor and ELISA assays (area under curve values (AUC): ELISA 0.93; SAW 0.89). Furthermore, both analytical approaches yielded readouts which distinguished between heath, gingivitis and periodontitis, correlated identically with clinical measures of periodontal disease and recorded similar post-treatment decreases in salivary MMP-8 in periodontitis. The assay time for our prototype device is 20 minutes. The prototype SAW biosensor is a novel and rapid method of monitoring periodontitis which delivers similar analytical performance to conventional laboratory assays.


Assuntos
Técnicas Biossensoriais/métodos , Metaloproteinase 8 da Matriz/análise , Periodontite/metabolismo , Saliva/química , Acústica , Adulto , Anticorpos/imunologia , Diagnóstico Bucal/métodos , Feminino , Gengivite/diagnóstico , Gengivite/metabolismo , Humanos , Imunoensaio/métodos , Masculino , Metaloproteinase 8 da Matriz/imunologia , Pessoa de Meia-Idade , Periodontite/diagnóstico
18.
J Biol Chem ; 294(23): 9016-9028, 2019 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-31064841

RESUMO

The misfolding and aggregation of α-synuclein (αsyn) in the central nervous system is associated with a group of neurodegenerative disorders referred to as the synucleinopathies. In addition to being a pathological hallmark of disease, it is now well-established that upon misfolding, αsyn acquires pathogenic properties, such as neurotoxicity, that can contribute to disease development. The mechanisms that produce αsyn misfolding and the molecular events underlying the neuronal damage caused by these misfolded species are not well-defined. A consistent observation that may be relevant to αsyn's pathogenicity is its ability to associate with lipids. This appears important not only to how αsyn aggregates, but also to the mechanism by which the misfolded protein causes intracellular damage. This review discusses the current literature reporting a role of lipids in αsyn misfolding and neurotoxicity in various synucleinopathy disorders and provides an overview of current methods to assess protein misfolding and pathogenicity both in vitro and in vivo.


Assuntos
Lipídeos/química , alfa-Sinucleína/metabolismo , Sistema Nervoso Central/metabolismo , Ácidos Graxos Insaturados/química , Ácidos Graxos Insaturados/metabolismo , Humanos , Agregação Patológica de Proteínas , Deficiências na Proteostase/metabolismo , Deficiências na Proteostase/patologia , alfa-Sinucleína/química
19.
PLoS Pathog ; 15(4): e1007712, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30970042

RESUMO

Although considerable evidence supports that misfolded prion protein (PrPSc) is the principal component of "prions", underpinning both transmissibility and neurotoxicity, clear consensus around a number of fundamental aspects of pathogenesis has not been achieved, including the time of appearance of neurotoxic species during disease evolution. Utilizing a recently reported electrophysiology paradigm, we assessed the acute synaptotoxicity of ex vivo PrPSc prepared as crude homogenates from brains of M1000 infected wild-type mice (cM1000) harvested at time-points representing 30%, 50%, 70% and 100% of the terminal stage of disease (TSD). Acute synaptotoxicity was assessed by measuring the capacity of cM1000 to impair hippocampal CA1 region long-term potentiation (LTP) and post-tetanic potentiation (PTP) in explant slices. Of particular note, cM1000 from 30% of the TSD was able to cause significant impairment of LTP and PTP, with the induced failure of LTP increasing over subsequent time-points while the capacity of cM1000 to induce PTP failure appeared maximal even at this early stage of disease progression. Evidence that the synaptotoxicity directly related to PrP species was demonstrated by the significant rescue of LTP dysfunction at each time-point through immuno-depletion of >50% of total PrP species from cM1000 preparations. Moreover, similar to our previous observations at the terminal stage of M1000 prion disease, size fractionation chromatography revealed that capacity for acute synpatotoxicity correlated with predominance of oligomeric PrP species in infected brains across all time points, with the profile appearing maximised by 50% of the TSD. Using enhanced sensitivity western blotting, modestly proteinase K (PK)-resistant PrPSc was detectable at very low levels in cM1000 at 30% of the TSD, becoming robustly detectable by 70% of the TSD at which time substantial levels of highly PK-resistant PrPSc was also evident. Further illustrating the biochemical evolution of acutely synaptotoxic species the synaptotoxicity of cM1000 from 30%, 50% and 70% of the TSD, but not at 100% TSD, was abolished by digestion of immuno-captured PrP species with mild PK treatment (5µg/ml for an hour at 37°C), demonstrating that the predominant synaptotoxic PrPSc species up to and including 70% of the TSD were proteinase-sensitive. Overall, these findings in combination with our previous assessments of transmitting prions support that synaptotoxic and infectious M1000 PrPSc species co-exist from at least 30% of the TSD, simultaneously increasing thereafter, albeit with eventual plateauing of transmitting conformers.


Assuntos
Evolução Biológica , Encefalopatias/patologia , Proteínas PrPSc/metabolismo , Doenças Priônicas/patologia , Príons/patogenicidade , Sinapses/patologia , Animais , Encefalopatias/etiologia , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Doenças Priônicas/etiologia , Proteólise , Sinapses/metabolismo
20.
Muscle Nerve ; 60(1): 62-66, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30920665

RESUMO

INTRODUCTION: Charcot-Marie-Tooth (CMT) phenotypes can be distinguished by electrophysiology and genetic analysis but few can be identified by their clinical characteristics. Distinctive phenotypes are useful in identifying affected individuals and providing additional clues about the mechanism of the neuropathy. Cranial neuropathies are uncommon features of CMT, and few reports of familial hemifacial spasm (HFS) and trigeminal neuralgia (TN) have been published. METHODS: Sixty-three members of a large CMT 1B kindred were assessed for signs of peripheral neuropathy and cranial neuropathies then tested for the G163R mutation in the myelin protein zero (MPZ) gene. RESULTS: Of 27 individuals with the G163R mutation in MPZ, 10 had HFS or TN. Co-existing HFS and TN were found in 3 of these and 4 had bilateral HFS or TN. CONCLUSIONS: This kindred exhibits a distinct CMT phenotype characterized by the development of HFS or TN decades after clinical signs of hereditary neuropathy are manifest. Muscle Nerve, 2019.


Assuntos
Doença de Charcot-Marie-Tooth/fisiopatologia , Espasmo Hemifacial/fisiopatologia , Neuralgia do Trigêmeo/fisiopatologia , Adolescente , Adulto , Idoso , Doença de Charcot-Marie-Tooth/complicações , Doença de Charcot-Marie-Tooth/genética , Família , Feminino , Espasmo Hemifacial/complicações , Espasmo Hemifacial/genética , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Proteína P0 da Mielina/genética , Linhagem , Fenótipo , Neuralgia do Trigêmeo/complicações , Neuralgia do Trigêmeo/genética , Adulto Jovem
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