RESUMEN
TAR DNA-binding protein 43 (TDP-43) proteinopathy in brain cells is the hallmark of amyotrophic lateral sclerosis (ALS) but its cause remains elusive. Asparaginase-like-1 protein (ASRGL1) cleaves isoaspartates, which alter protein folding and susceptibility to proteolysis. ASRGL1 gene harbors a copy of the human endogenous retrovirus HML-2, whose overexpression contributes to ALS pathogenesis. Here we show that ASRGL1 expression was diminished in ALS brain samples by RNA sequencing, immunohistochemistry, and western blotting. TDP-43 and ASRGL1 colocalized in neurons but, in the absence of ASRGL1, TDP-43 aggregated in the cytoplasm. TDP-43 was found to be prone to isoaspartate formation and a substrate for ASRGL1. ASRGL1 silencing triggered accumulation of misfolded, fragmented, phosphorylated and mislocalized TDP-43 in cultured neurons and motor cortex of female mice. Overexpression of ASRGL1 restored neuronal viability. Overexpression of HML-2 led to ASRGL1 silencing. Loss of ASRGL1 leading to TDP-43 aggregation may be a critical mechanism in ALS pathophysiology.
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Esclerosis Amiotrófica Lateral , Asparaginasa , Proteínas de Unión al ADN , Neuronas , Proteinopatías TDP-43 , Animales , Femenino , Humanos , Masculino , Ratones , Esclerosis Amiotrófica Lateral/metabolismo , Esclerosis Amiotrófica Lateral/genética , Esclerosis Amiotrófica Lateral/patología , Asparaginasa/genética , Asparaginasa/metabolismo , Autoantígenos/genética , Autoantígenos/metabolismo , Encéfalo/metabolismo , Encéfalo/patología , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Corteza Motora/metabolismo , Corteza Motora/patología , Neuronas/metabolismo , Neuronas/patología , Proteinopatías TDP-43/metabolismo , Proteinopatías TDP-43/patología , Proteinopatías TDP-43/genética , Retrovirus Endógenos/genética , Retrovirus Endógenos/metabolismoRESUMEN
Rehabilitation training is essential for a successful recovery of upper extremity function after stroke. Training programs are typically conducted in hospitals or rehabilitation centers, supervised by specialized medical professionals. However, frequent visits to hospitals can be burdensome for stroke patients with limited mobility. We consider a self-administered rehabilitation system based on a mobile application in which patients can periodically upload videos of themselves performing reach-to-grasp tasks to receive recommendations for self-managed exercises or progress reports. Sensing equipment aside from cameras is typically unavailable in the home environment. A key contribution of our work is to propose a deep learning-based assessment model trained only with video data. As all patients carry out identical tasks, a fine-grained assessment of task execution is required. Our model addresses this difficulty by learning RGB and optical flow data in a complementary manner. The correlation between the RGB and optical flow data is captured by a novel module for modality fusion using cross-attention with Transformers. Experiments showed that our model achieved higher accuracy in movement assessment than existing methods for action recognition. Based on the assessment model, we developed a patient-centered, solution-based mobile application for upper extremity exercises for hemiplegia, which can recommend 57 exercises with three levels of difficulty. A prototype of our application was evaluated by potential end-users and achieved a good quality score on the Mobile Application Rating Scale (MARS).
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Aplicaciones Móviles , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Humanos , Rehabilitación de Accidente Cerebrovascular/métodos , Extremidad Superior , Movimiento , Recuperación de la FunciónRESUMEN
Human endogenous retroviruses (HERVs) are ancestral viral relics that constitute nearly 8% of the human genome. Although normally silenced, the most recently integrated provirus HERV-K (HML-2) can be reactivated in certain cancers. Here, we report pathological expression of HML-2 in malignant gliomas in both cerebrospinal fluid and tumor tissue that was associated with a cancer stem cell phenotype and poor outcomes. Using single-cell RNA-Seq, we identified glioblastoma cellular populations with elevated HML-2 transcripts in neural progenitor-like cells (NPC-like) that drive cellular plasticity. Using CRISPR interference, we demonstrate that HML-2 critically maintained glioblastoma stemness and tumorigenesis in both glioblastoma neurospheres and intracranial orthotopic murine models. Additionally, we demonstrate that HML-2 critically regulated embryonic stem cell programs in NPC-derived astroglia and altered their 3D cellular morphology by activating the nuclear transcription factor OCT4, which binds to an HML-2-specific long-terminal repeat (LTR5Hs). Moreover, we discovered that some glioblastoma cells formed immature retroviral virions, and inhibiting HML-2 expression with antiretroviral drugs reduced reverse transcriptase activity in the extracellular compartment, tumor viability, and pluripotency. Our results suggest that HML-2 fundamentally contributes to the glioblastoma stem cell niche. Because persistence of glioblastoma stem cells is considered responsible for treatment resistance and recurrence, HML-2 may serve as a unique therapeutic target.
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Retrovirus Endógenos , Glioblastoma , Humanos , Animales , Ratones , Retrovirus Endógenos/genética , Glioblastoma/genética , Nicho de Células Madre , Provirus/genéticaRESUMEN
BACKGROUND AND OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can cause a wide range of neurologic complications; however, its neuropenetrance during the acute phase of the illness is unknown. METHODS: Extracellular vesicles were isolated from brain biopsy tissue from a patient undergoing epilepsy surgery using ultracentrifugation and analyzed by Western blot and qPCR for the presence of virus protein and RNA, respectively. Biopsy tissue was assessed by immunohistochemistry for the presence of microvascular damage and compared with 3 other non-COVID surgical epilepsy brain tissues. RESULTS: We demonstrate the presence of viral nucleocapsid protein in extracellular vesicles and microvascular disease in the brain of a patient undergoing epilepsy surgery shortly after SARS-CoV-2 infection. Endothelial cell activation was indicated by increased levels of platelet endothelial cell adhesion molecule-1 and was associated with fibrinogen leakage and immune cell infiltration in the biopsy tissue as compared with control non-COVID surgical epilepsy brain tissues. DISCUSSION: Despite the lack of evidence of viral replication within the brain, the presence of the nucleocapsid protein was associated with disease-specific endothelial cell activation, fibrinogen leakage, and immune cell infiltration.
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COVID-19 , SARS-CoV-2 , Humanos , Proteínas de la Nucleocápside de Coronavirus/metabolismo , Nucleocápside/metabolismo , Proteínas de la Nucleocápside/genética , Proteínas de la Nucleocápside/metabolismo , Encéfalo/metabolismoRESUMEN
There is a continuing unmet medical need to develop neuroprotective strategies to treat neurodegenerative disorders. To address this need, we screened over 2000 compounds for potential neuroprotective activity in a model of oxidative stress and found that numerous antifungal agents were neuroprotective. Of the identified compounds, fluconazole was further characterized. Fluconazole was able to prevent neurite retraction and cell death in in vitro and in vivo models of toxicity. Fluconazole protected neurons in a concentration-dependent manner and exhibited efficacy against several toxic agents, including 3-nitropropionic acid, N-methyl D-aspartate, 6-hydroxydopamine, and the HIV proteins Tat and gp120. In vivo studies indicated that systemically administered fluconazole was neuroprotective in animals treated with 3-nitropropionic acid and prevented gp120-mediated neuronal loss. In addition to neuroprotection, fluconazole also induced proliferation of neural progenitor cells in vitro and in vivo. Fluconazole mediates these effects through upregulation and signaling via the insulin growth factor-1 receptor which results in decreased cAMP production and increased phosphorylation of Akt. Blockade of the insulin growth factor-1 receptor signaling with the selective inhibitor AG1024 abrogated the effects of fluconazole. Our studies suggest that fluconazole may be an attractive candidate for treatment of neurodegenerative diseases due to its protective properties against several categories of neuronal insults and its ability to spur neural progenitor cell proliferation.
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Insulinas , Enfermedades Neurodegenerativas , Fármacos Neuroprotectores , Animales , Receptor IGF Tipo 1/metabolismo , Neuroprotección , Fluconazol/farmacología , Fármacos Neuroprotectores/farmacología , Proteínas Proto-Oncogénicas c-akt , Oxidopamina , Antifúngicos , Ácido D-AspárticoRESUMEN
OBJECTIVE: Human endogenous retroviruses have been implicated in neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). Expression of human endogenous retrovirus K (HERV-K) subtype HML-2 envelope (Env) in human neuronal cultures and in transgenic mice results in neurotoxicity and neurodegeneration, and mice expressing HML-2 Env display behavioral and neuromuscular characteristics resembling ALS. This study aims to characterize the neurotoxic properties of HML-2 Env. METHODS: Env neurotoxicity was detected in ALS cerebrospinal fluid and confirmed using recombinant Env protein in a cell-based assay and a mouse model. The mechanism of neurotoxicity was assessed with immunoprecipitation followed by mass spectrometry and Western blot, and by screening a panel of inhibitors. RESULTS: We observed that recombinant HML-2 Env protein caused neurotoxicity resulting in neuronal cell death, retraction of neurites, and decreased neuronal electrical activity. Injection of the Env protein into the brains of mice also resulted in neuronal cell death. HML-2 Env protein was also found in the cerebrospinal fluid of patients with sporadic ALS. The neurotoxic properties of the Env and the cerebrospinal fluid could be rescued with the anti-Env antibody. The Env was found to bind to CD98HC complexed to ß1 integrin on the neuronal cell surface. Using a panel of compounds to screen for their ability to block Env-induced neurotoxicity, we found that several compounds were protective and are linked to the ß1 integrin pathway. INTERPRETATION: HERV-K Env is released extracellularly in ALS and causes neurotoxicity via a novel mechanism. Present results pave the way for new treatment strategies in sporadic ALS. ANN NEUROL 2022;92:545-561.
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Esclerosis Amiotrófica Lateral , Retrovirus Endógenos , Esclerosis Amiotrófica Lateral/genética , Animales , Productos del Gen env , Humanos , Integrina beta1 , Ratones , Ratones TransgénicosRESUMEN
The underlying mechanisms by which severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to acute and long-term neurological manifestations remains obscure. We aimed to characterize the neuropathological changes in patients with coronavirus disease 2019 and determine the underlying pathophysiological mechanisms. In this autopsy study of the brain, we characterized the vascular pathology, the neuroinflammatory changes and cellular and humoral immune responses by immunohistochemistry. All patients died during the first wave of the pandemic from March to July 2020. All patients were adults who died after a short duration of the infection, some had died suddenly with minimal respiratory involvement. Infection with SARS-CoV-2 was confirmed on ante-mortem or post-mortem testing. Descriptive analysis of the pathological changes and quantitative analyses of the infiltrates and vascular changes were performed. All patients had multifocal vascular damage as determined by leakage of serum proteins into the brain parenchyma. This was accompanied by widespread endothelial cell activation. Platelet aggregates and microthrombi were found adherent to the endothelial cells along vascular lumina. Immune complexes with activation of the classical complement pathway were found on the endothelial cells and platelets. Perivascular infiltrates consisted of predominantly macrophages and some CD8+ T cells. Only rare CD4+ T cells and CD20+ B cells were present. Astrogliosis was also prominent in the perivascular regions. Microglial nodules were predominant in the hindbrain, which were associated with focal neuronal loss and neuronophagia. Antibody-mediated cytotoxicity directed against the endothelial cells is the most likely initiating event that leads to vascular leakage, platelet aggregation, neuroinflammation and neuronal injury. Therapeutic modalities directed against immune complexes should be considered.
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COVID-19 , Enfermedades del Sistema Nervioso , Adulto , Complejo Antígeno-Anticuerpo , Activación de Complemento , Células Endoteliales , Humanos , Inflamación , SARS-CoV-2RESUMEN
COVID survivors frequently experience lingering neurological symptoms that resemble cancer-therapy-related cognitive impairment, a syndrome for which white matter microglial reactivity and consequent neural dysregulation is central. Here, we explored the neurobiological effects of respiratory SARS-CoV-2 infection and found white-matter-selective microglial reactivity in mice and humans. Following mild respiratory COVID in mice, persistently impaired hippocampal neurogenesis, decreased oligodendrocytes, and myelin loss were evident together with elevated CSF cytokines/chemokines including CCL11. Systemic CCL11 administration specifically caused hippocampal microglial reactivity and impaired neurogenesis. Concordantly, humans with lasting cognitive symptoms post-COVID exhibit elevated CCL11 levels. Compared with SARS-CoV-2, mild respiratory influenza in mice caused similar patterns of white-matter-selective microglial reactivity, oligodendrocyte loss, impaired neurogenesis, and elevated CCL11 at early time points, but after influenza, only elevated CCL11 and hippocampal pathology persisted. These findings illustrate similar neuropathophysiology after cancer therapy and respiratory SARS-CoV-2 infection which may contribute to cognitive impairment following even mild COVID.
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COVID-19 , Gripe Humana , Neoplasias , Animales , Humanos , Gripe Humana/patología , Ratones , Microglía/patología , Vaina de Mielina , Neoplasias/patología , SARS-CoV-2RESUMEN
Survivors of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection frequently experience lingering neurological symptoms, including impairment in attention, concentration, speed of information processing and memory. This long-COVID cognitive syndrome shares many features with the syndrome of cancer therapy-related cognitive impairment (CRCI). Neuroinflammation, particularly microglial reactivity and consequent dysregulation of hippocampal neurogenesis and oligodendrocyte lineage cells, is central to CRCI. We hypothesized that similar cellular mechanisms may contribute to the persistent neurological symptoms associated with even mild SARS-CoV-2 respiratory infection. Here, we explored neuroinflammation caused by mild respiratory SARS-CoV-2 infection - without neuroinvasion - and effects on hippocampal neurogenesis and the oligodendroglial lineage. Using a mouse model of mild respiratory SARS-CoV-2 infection induced by intranasal SARS-CoV-2 delivery, we found white matter-selective microglial reactivity, a pattern observed in CRCI. Human brain tissue from 9 individuals with COVID-19 or SARS-CoV-2 infection exhibits the same pattern of prominent white matter-selective microglial reactivity. In mice, pro-inflammatory CSF cytokines/chemokines were elevated for at least 7-weeks post-infection; among the chemokines demonstrating persistent elevation is CCL11, which is associated with impairments in neurogenesis and cognitive function. Humans experiencing long-COVID with cognitive symptoms (48 subjects) similarly demonstrate elevated CCL11 levels compared to those with long-COVID who lack cognitive symptoms (15 subjects). Impaired hippocampal neurogenesis, decreased oligodendrocytes and myelin loss in subcortical white matter were evident at 1 week, and persisted until at least 7 weeks, following mild respiratory SARS-CoV-2 infection in mice. Taken together, the findings presented here illustrate striking similarities between neuropathophysiology after cancer therapy and after SARS-CoV-2 infection, and elucidate cellular deficits that may contribute to lasting neurological symptoms following even mild SARS-CoV-2 infection.
RESUMEN
Atypical Teratoid Rhabdoid Tumor (AT/RT) is a rare pediatric central nervous system cancer often characterized by deletion or mutation of SMARCB1, a tumor suppressor gene. In this study, we found that SMARCB1 regulates Human Endogenous Retrovirus K (HERV-K, subtype HML-2) expression. HML-2 is a repetitive element scattered throughout the human genome, encoding several intact viral proteins that have been associated with stem cell maintenance and tumorigenesis. We found HML-2 env expression in both the intracellular and extracellular compartments in all AT/RT cell lines (n = 4) and in 95% of AT/RT patient tissues (n = 37) evaluated. SMARCB1 knock-down in neural stem cells (NSCs) led to an upregulation of HML-2 transcription. We found that SMARCB1 binds adjacent to the HML-2 promoter, repressing its transcription via chromatin immunoprecipitation; restoration of SMARCB1 expression in AT/RT cell lines significantly downregulated HML-2 expression. Further, targeted downregulation of HML-2 transcription via CRISPR-dCas9 coupled with suppressor proteins led to cellular dispersion, decreased proliferation, and cell death in vitro. HML-2 knock-down with shRNA, siRNA, and CRISPR-dCas9 significantly decreased Ras expression as measured by qRT-PCR, suggesting that HML-2 modulates MAPK/ERK signaling in AT/RT cells. Overexpression of NRAS was sufficient to restore cellular proliferation, and MYC, a transcription factor downstream of NRAS, was bound to the HERV-K LTR significantly more in the absence of SMARCB1 expression in AT/RT cells. We show a mechanism by which these undifferentiated tumors remain pluripotent, and we demonstrate that their formation is aided by aberrant HML-2 activation, which is dependent on SMARCB1 and its interaction with MYC.
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Transformación Celular Neoplásica/genética , Retrovirus Endógenos/genética , Tumor Rabdoide/etiología , Tumor Rabdoide/patología , Proteína SMARCB1/deficiencia , Eliminación de Secuencia , Activación Viral/genética , Biomarcadores de Tumor , Línea Celular Tumoral , Proliferación Celular , Micropartículas Derivadas de Células/metabolismo , Susceptibilidad a Enfermedades , GTP Fosfohidrolasas/metabolismo , Regulación de la Expresión Génica , Humanos , Proteínas de la Membrana/metabolismo , Secuencias Repetitivas de Ácidos Nucleicos , Transducción de SeñalRESUMEN
BACKGROUND The number of organ donations from hepatitis B virus (HBV) or hepatitis C virus (HCV)-positive donors is gradually increasing; however, the current status of organ donation from brain-dead donors with hepatitis in South Korea has not been analyzed. This study aimed to analyze this. MATERIAL AND METHODS In total, 9210 potential brain deaths were reported in South Korea from January 2013 to December 2017, of which 333 were hepatitis carriers (HBV, n=246; HCV, n=87). Based on the data from the Korean Network for Organ Sharing and Korea Organ Donation Agency, 2460 completion of transplantations from brain-dead donors have been performed, of which 71 were hepatitis carriers (HBV, n=60; HCV, n=11). RESULTS There were 60 and 11 transplantations from HBV- and HCV-positive brain-dead donors, respectively. The main reasons for organ transplantation failure were recipient's refusal (n=90), unsuitability as donors (n=80), non-brain death (n=45), and cardiac death (n=20). There were 71 and 31 kidney and liver donations, respectively; the average number of organs donated by HBV-positive donors was higher than that donated by HCV-positive donors. HBV-positive donors donated more hearts and livers than HCV-positive donors. CONCLUSIONS There are few organ donations from brain-dead donors with hepatitis B or C which led to transplantation completion in South Korea, and the main reasons for failure are recipient's refusal to receive organs from donors with hepatitis and unsuitability for donation due to active viral conditions. To promote organ transplantations from donors with hepatitis B and C virus, we could consider 3 strategies: 1) reducing recipient's refusal rates by educating recipients and their families on the outcomes of organ donation from hepatitis carriers, 2) establishing treatment protocols for infection management after organ transplantations from HBV/HCV brain-dead donors, and 3) increasing the relevant experience of medical staff.
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Hepatitis B , Hepatitis C , Trasplante de Órganos , Donantes de Tejidos , Obtención de Tejidos y Órganos , Adulto , Análisis de Datos , Femenino , Humanos , Masculino , Persona de Mediana Edad , República de CoreaRESUMEN
When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen â¼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.
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Antivirales/análisis , Antivirales/farmacología , Evaluación Preclínica de Medicamentos , Ensayos Analíticos de Alto Rendimiento , Inhibidores de Proteasas/análisis , Inhibidores de Proteasas/farmacología , Virus Zika/efectos de los fármacos , Animales , Antivirales/uso terapéutico , Inteligencia Artificial , Chlorocebus aethiops , Modelos Animales de Enfermedad , Inmunocompetencia , Concentración 50 Inhibidora , Metaciclina/farmacología , Ratones Endogámicos C57BL , Inhibidores de Proteasas/uso terapéutico , Relación Estructura-Actividad Cuantitativa , Bibliotecas de Moléculas Pequeñas , Células Vero , Infección por el Virus Zika/tratamiento farmacológico , Infección por el Virus Zika/virologíaRESUMEN
BACKGROUNDCerebral malaria (CM) accounts for nearly 400,000 deaths annually in African children. Current dogma suggests that CM results from infected RBC (iRBC) sequestration in the brain microvasculature and resulting sequelae. Therapies targeting these events have been unsuccessful; findings in experimental models suggest that CD8+ T cells drive disease pathogenesis. However, these data have largely been ignored because corroborating evidence in humans is lacking. This work fills a critical gap in our understanding of CM pathogenesis that is impeding development of therapeutics.METHODSUsing multiplex immunohistochemistry, we characterized cerebrovascular immune cells in brain sections from 34 children who died from CM or other causes. Children were grouped by clinical diagnosis (CM+ or CM-), iRBC sequestration (Seqhi, Seqlo, Seq0) and HIV status (HIV+ or HIV-).RESULTSWe identified effector CD3+CD8+ T cells engaged on the cerebrovasculature in 69% of CM+ HIV- children. The number of intravascular CD3+CD8+ T cells was influenced by CM status (CM+ > CM-, P = 0.004) and sequestration level (Seqhi > Seqlo, P = 0.010). HIV coinfection significantly increased T cell numbers (P = 0.017) and shifted cells from an intravascular (P = 0.004) to perivascular (P < 0.0001) distribution.CONCLUSIONWithin the studied cohort, CM is associated with cerebrovascular engagement of CD3+CD8+ T cells, which is exacerbated by HIV coinfection. Thus, CD3+CD8+ T cells are highly promising targets for CM adjunctive therapy, opening new avenues for the treatment of this deadly disease.FUNDINGThis research was supported by the Intramural Research Program of the National Institutes of Health.
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Encéfalo/irrigación sanguínea , Encéfalo/inmunología , Linfocitos T CD8-positivos/inmunología , Malaria Cerebral/inmunología , Encéfalo/patología , Linfocitos T CD8-positivos/patología , Niño , Preescolar , Femenino , Humanos , Lactante , Malaria Cerebral/patología , MasculinoRESUMEN
OBJECTIVE: To determine the underlying etiology in a patient with progressive dementia with extrapyramidal signs and chronic inflammation referred to the National Institutes of Health Undiagnosed Diseases Program. METHODS: Extensive investigations included metabolic profile, autoantibody panel, infectious etiologies, genetic screening, whole exome sequencing, and the phage-display assay, VirScan, for viral immune responses. An etiological diagnosis was established postmortem. RESULTS: Using VirScan, enrichment of dengue viral antibodies was detected in cerebrospinal fluid as compared to serum. No virus was detected in serum or cerebrospinal fluid, but postmortem analysis confirmed dengue virus in the brain by immunohistochemistry, in situ hybridization, quantitative polymerase chain reaction, and sequencing. Dengue virus was also detectable by polymerase chain reaction and sequencing from brain biopsy tissue collected 33 months antemortem, confirming a chronic infection despite a robust immune response directed against the virus. Immunoprofiling and whole exome sequencing of the patient did not reveal any immunodeficiency, and sequencing of the virus demonstrated wild-type dengue virus in the central nervous system. INTERPRETATION: Dengue virus is the most common arbovirus worldwide and represents a significant public health concern. Infections with dengue virus are usually self-limiting, and chronic dengue infections have not been previously reported. Our findings suggest that dengue virus infections may persist in the central nervous system causing a panencephalitis and should be considered in patients with progressive dementia with extrapyramidal features in endemic regions or with relevant travel history. Furthermore, this work highlights the utility of comprehensive antibody profiling assays to aid in the diagnosis of encephalitis of unknown etiology. ANN NEUROL 2019;86:695-703.
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Dengue/complicaciones , Dengue/patología , Encefalitis Viral/etiología , Encefalitis Viral/patología , Enfermedad Crónica , Demencia , Virus del Dengue , Resultado Fatal , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Thymosin ß4 (Tß4) regulates the expression of molecules associated with dentinogenesis, including bone sialoprotein (BSP). BSP regulates the initiation of mineralization and the direction of dentin growth. However, the association between Tß4 signaling and BSP expression in odontoblasts remains unclear. Therefore, the aim of the present study was to investigate Tß4 mRNA expression in odontoblasts during dentinogenesis and the association between the Tß4 signaling pathway and BSP expression in MDPC23 odontoblastic cells. Expression and localization of Tß4 mRNA was determined by in situ hybridization during mouse tooth development. The effect of Tß4 signaling on BSP expression was investigated by reverse transcription polymerase chain reaction, western blot analysis, immunofluorescence and a luciferase reporter assay in the presence or absence of specific inhibitors of mitogen activated protein kinase kinase (PD98059) and mothers against decapentaplegic homolog 3 (Smad3; SIS3) in MDPC23 cells. The expression of Tß4 mRNA in the odontoblast layer was highest at postnatal day 5, known as the advanced bell stage, when odontoblasts actively secrete dentin matrix proteins. Tß4 increased BSP mRNA and protein levels in MDPC23 cells, but this was inhibited by PD98059 or SIS3 treatment. Tß4 increased levels of phosphorylated (p) extracellular signalregulated kinase (ERK)1/2, pSmad3, pßcatenin, and runtrelated transcription factor 2 (Runx2) protein, but these effects were inhibited by PD98059 or SIS3. Tß4 induced the nuclear translocation of Runx2 and pSmad3, while nuclear translocation of ßcatenin was decreased. Tß4 significantly increased BSP promoter activity, which was decreased by PD98059 or SIS3 treatment. Tß4 induced BSP expression in MDPC23 cells via ERK and Smad3 signaling pathways, suggesting its role as a signaling molecule in odontoblasts for regulating BSP secretion during dentinogenesis.
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Sialoproteína de Unión a Integrina/genética , Sistema de Señalización de MAP Quinasas , Odontoblastos/metabolismo , Transducción de Señal , Proteína smad3/metabolismo , Timosina/metabolismo , Regulación hacia Arriba , Animales , Línea Celular , Femenino , Regulación del Desarrollo de la Expresión Génica , Ratones Endogámicos ICR , Regiones Promotoras Genéticas , Timosina/genéticaRESUMEN
Nodding syndrome is an epileptic disorder of unknown etiology that occurs in children in East Africa. There is an epidemiological association with Onchocerca volvulus, the parasitic worm that causes onchocerciasis (river blindness), but there is limited evidence that the parasite itself is neuroinvasive. We hypothesized that nodding syndrome may be an autoimmune-mediated disease. Using protein chip methodology, we detected autoantibodies to leiomodin-1 more abundantly in patients with nodding syndrome compared to unaffected controls from the same village. Leiomodin-1 autoantibodies were found in both the sera and cerebrospinal fluid of patients with nodding syndrome. Leiomodin-1 was found to be expressed in mature and developing human neurons in vitro and was localized in mouse brain to the CA3 region of the hippocampus, Purkinje cells in the cerebellum, and cortical neurons, structures that also appear to be affected in patients with nodding syndrome. Antibodies targeting leiomodin-1 were neurotoxic in vitro, and leiomodin-1 antibodies purified from patients with nodding syndrome were cross-reactive with O. volvulus antigens. This study provides initial evidence supporting the hypothesis that nodding syndrome is an autoimmune epileptic disorder caused by molecular mimicry with O. volvulus antigens and suggests that patients may benefit from immunomodulatory therapies.
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Enfermedades Autoinmunes/parasitología , Síndrome del Cabeceo/inmunología , Síndrome del Cabeceo/parasitología , Onchocerca volvulus/fisiología , Secuencia de Aminoácidos , Animales , Autoanticuerpos/sangre , Autoanticuerpos/líquido cefalorraquídeo , Autoantígenos/química , Autoantígenos/inmunología , Enfermedades Autoinmunes/sangre , Sistema Nervioso Central/metabolismo , Sistema Nervioso Central/patología , Niño , Preescolar , Reacciones Cruzadas/inmunología , Proteínas del Citoesqueleto/química , Proteínas del Citoesqueleto/inmunología , Femenino , Proteínas del Helminto/metabolismo , Humanos , Masculino , Síndrome del Cabeceo/sangre , Síndrome del Cabeceo/líquido cefalorraquídeoRESUMEN
Deposition of amyloid-ß plaques is increased in the brains of HIV-infected individuals, and the HIV transactivator of transcription (Tat) protein affects amyloidogenesis through several indirect mechanisms. Here, we investigated direct interactions between Tat and amyloid-ß peptide. Our in vitro studies showed that in the presence of Tat, uniform amyloid fibrils become double twisted fibrils and further form populations of thick unstructured filaments and aggregates. Specifically, Tat binding to the exterior surfaces of the Aß fibrils increases ß-sheet formation and lateral aggregation into thick multifibrillar structures, thus producing fibers with increased rigidity and mechanical resistance. Furthermore, Tat and Aß aggregates in complex synergistically induced neurotoxicity both in vitro and in animal models. Increased rigidity and mechanical resistance of the amyloid-ß-Tat complexes coupled with stronger adhesion due to the presence of Tat in the fibrils may account for increased damage, potentially through pore formation in membranes.
Asunto(s)
Péptidos beta-Amiloides/química , Péptidos beta-Amiloides/toxicidad , Amiloide/toxicidad , Neurotoxinas/toxicidad , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/química , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/toxicidad , Amiloide/química , Péptidos beta-Amiloides/metabolismo , Animales , Células Cultivadas , Dicroismo Circular , Técnica del Anticuerpo Fluorescente , Humanos , Ratones Transgénicos , Microscopía de Fuerza Atómica , Modelos Biológicos , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Neurotoxinas/química , Agregado de Proteínas/efectos de los fármacos , Unión Proteica/efectos de los fármacos , Estructura Secundaria de Proteína , Ratas Sprague-Dawley , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/metabolismoRESUMEN
The underlying mechanisms for increased neurodegeneration and neurocognitive deficits in HIV-infected people are unclear. Therefore, this study was aimed to investigate the mechanisms of increased neurodegeneration in 5-month old male HIV-1 Transgenic (Tg) rats compared to the age- and gender-matched wild-type (WT) by evaluating histological changes and biochemical parameters of the key proteins involved in the cell death signaling and apoptosis. Histological and immunohistochemical analyses revealed decreased neuronal cells with elevated astrogliosis in HIV-1 Tg rats compared to WT. Mechanistic studies revealed that increased levels of nitroxidative stress marker proteins such as NADPH-oxidase, cytochrome P450-2E1 (CYP2E1), inducible nitric oxide synthase (iNOS), the stress-activated mitogen-activated protein kinases such as JNK and p38K, activated cell-cycle dependent CDK5, hypoxia-inducible protein-1α, nitrated proteins, hyperphosphorylated tau, and amyloid plaques in HIV-Tg rats were consistently observed in HIV-1 Tg rats. Confocal microscopy and cell viability analyses showed that treatment with an antioxidant N-acetylcysteine or a specific inhibitor of iNOS 1400W significantly prevented the increased apoptosis of neuro-2A cells by HIV-1 Tat or gp120 protein, demonstrating the causal role of HIV-1 mediated nitroxidative stress and protein nitration in promoting neuronal cell death. Immunoprecipitation and immunoblot analysis confirmed nitration of Hsp90, evaluated as an example of nitrated proteins, suggesting possible involvement of nitrated proteins in neuronal damage. Further, activated p-JNK directly binds tau and phosphorylates multiple amino acids, suggesting an important role of p-JNK in tau hyperphosphorylation and tauopathy. These changes were accompanied with elevated levels of many apoptosis-related proteins Bax and cleaved (activated) caspase-3 as well as proinflammatory cytokines including TNF-α, IL-6 and MCP-1. Collectively, these results indicate that raised nitroxidative stress accompanied by elevated inflammation, cell death signaling pathway including activated p-JNK, C-terminal C99 amyloid fragment formation and tau hyperphosphorylation are responsible for increased apoptosis of neuronal cells and neurodegeneration in 5-month old HIV-Tg rats.