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1.
J Neurogenet ; 37(1-2): 10-19, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36000467

RESUMEN

Tau is a microtubule-associated protein that forms insoluble filaments that accumulate as neurofibrillary tangles in neurodegenerative diseases such as Alzheimer's disease and other related tauopathies. A relationship between abnormal Tau accumulation and ubiquitin-proteasome system impairment has been reported. However, the molecular mechanism linking Tau accumulation and ubiquitin proteasome system (UPS) dysfunction remains unclear. Here, we show that overexpression of wild-type or mutant (P301L) Tau increases the abundance of polyubiquitinated proteins and activates the autophagy-lysosome pathway in mammalian neuronal cells. Previous studies found that PTK2 inhibition mitigates toxicity induced by UPS impairment. Thus, we investigated whether PTK2 inhibition can attenuate Tau-induced UPS impairment and cell toxicity. We found that PTK2 inhibition significantly reduces Tau-induced death in mammalian neuronal cells. Moreover, overexpression of WT or mutant Tau increased the phosphorylation levels of PTK2 and p62. We also confirmed that PTK2 inhibition suppresses Tau-induced phosphorylation of PTK2 and p62. Furthermore, PTK2 inhibition significantly attenuated the climbing defect and shortened the lifespan in the Drosophila model of tauopathy. In addition, we observed that phosphorylation of p62 is markedly increased in Alzheimer's disease patients with tauopathies. Taken together, our results indicate that the UPS dysfunction induced by Tau accumulation might contribute directly to neurodegeneration in tauopathies and that PTK2 could be a promising therapeutic target for tauopathies.


Asunto(s)
Enfermedad de Alzheimer , Tauopatías , Animales , Enfermedad de Alzheimer/metabolismo , Proteínas tau/metabolismo , Fosforilación , Complejo de la Endopetidasa Proteasomal/metabolismo , Tauopatías/metabolismo , Ubiquitinas/metabolismo , Mamíferos/metabolismo
2.
J Neuroinflammation ; 17(1): 299, 2020 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-33054766

RESUMEN

BACKGROUND: Cytoplasmic inclusions of transactive response DNA binding protein of 43 kDa (TDP-43) in neurons and astrocytes are a feature of some neurodegenerative diseases, such as frontotemporal lobar degeneration with TDP-43 (FTLD-TDP) and amyotrophic lateral sclerosis (ALS). However, the role of TDP-43 in astrocyte pathology remains largely unknown. METHODS: To investigate whether TDP-43 overexpression in primary astrocytes could induce inflammation, we transfected primary astrocytes with plasmids encoding Gfp or TDP-43-Gfp. The inflammatory response and upregulation of PTP1B in transfected cells were examined using quantitative RT-PCR and immunoblot analysis. Neurotoxicity was analysed in a transwell coculture system of primary cortical neurons with astrocytes and cultured neurons treated with astrocyte-conditioned medium (ACM). We also examined the lifespan, performed climbing assays and analysed immunohistochemical data in pan-glial TDP-43-expressing flies in the presence or absence of a Ptp61f RNAi transgene. RESULTS: PTP1B inhibition suppressed TDP-43-induced secretion of inflammatory cytokines (interleukin 1 beta (IL-1ß), interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-α)) in primary astrocytes. Using a neuron-astrocyte coculture system and astrocyte-conditioned media treatment, we demonstrated that PTP1B inhibition attenuated neuronal death and mitochondrial dysfunction caused by overexpression of TDP-43 in astrocytes. In addition, neuromuscular junction (NMJ) defects, a shortened lifespan, inflammation and climbing defects caused by pan-glial overexpression of TDP-43 were significantly rescued by downregulation of ptp61f (the Drosophila homologue of PTP1B) in flies. CONCLUSIONS: These results indicate that PTP1B inhibition mitigates the neuronal toxicity caused by TDP-43-induced inflammation in mammalian astrocytes and Drosophila glial cells.


Asunto(s)
Astrocitos/metabolismo , Proteínas de Unión al ADN/biosíntesis , Mediadores de Inflamación/metabolismo , Degeneración Nerviosa/metabolismo , Proteína Tirosina Fosfatasa no Receptora Tipo 1/antagonistas & inhibidores , Proteína Tirosina Fosfatasa no Receptora Tipo 1/biosíntesis , Animales , Animales Modificados Genéticamente , Astrocitos/patología , Células Cultivadas , Proteínas de Unión al ADN/genética , Drosophila , Expresión Génica , Mediadores de Inflamación/antagonistas & inhibidores , Masculino , Ratones , Ratones Endogámicos C57BL , Degeneración Nerviosa/genética , Degeneración Nerviosa/patología , Proteína Tirosina Fosfatasa no Receptora Tipo 1/genética
3.
Sensors (Basel) ; 17(9)2017 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-28832507

RESUMEN

The safety of children has always been an important issue, and several studies have been conducted to determine the stress state of a child to ensure the safety. Audio signals and biological signals including heart rate are known to be effective for stress state detection. However, collecting those data requires specialized equipment, which is not appropriate for the constant monitoring of children, and advanced data analysis is required for accurate detection. In this regard, we propose a stress state detection framework which utilizes both audio signal and heart rate collected from wearable devices, and adopted machine learning methods for the detection. Experiments using real-world data were conducted to compare detection performances across various machine learning methods and noise levels of audio signal. Adopting the proposed framework in the real-world will contribute to the enhancement of child safety.


Asunto(s)
Dispositivos Electrónicos Vestibles , Niño , Frecuencia Cardíaca , Humanos , Aprendizaje Automático , Estrés Fisiológico
4.
J Appl Toxicol ; 36(10): 1332-42, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27080386

RESUMEN

Airborne nanoparticles PM0.1 (<100 nm in diameter) were collected and their chemical composition was determined. Al was by far the most abundant metal in the PM0.1 followed by Zn, Cr, Mn, Cu, Pb and Ni. Exposure to PM0.1 resulted in a cell viability decrease in human neuronal cells SH-SY5Y in a concentration-dependent manner. Upon treatment with N-acetylcysteine, however, cell viability was significantly recovered, suggesting the involvement of reactive oxygen species (ROS). Cellular DNA damage by PM0.1 was also detected by the Comet assay. PM0.1 -induced autophagic cell death was explained by an increase in the expression of microtubule-associated protein light chain 3A-ІІ (LC3A-ІІ) and autophagy-related protein Atg 3 and Atg 7. Analysis of 2-DE gels revealed that six proteins were upregulated, whereas eight proteins were downregulated by PM0.1 exposure. Neuroinflammation-related lithostathine and cyclophilin A complexed with dipeptide Gly-Pro, autophagy-related heat shock protein gp96 and neurodegeneration-related triosephosphate isomerase were significantly changed upon exposure to PM0.1 . These results, taken together, suggest that PM0.1 -induced oxidative stress via ROS generation plays a key role in autophagic cell death and differential protein expressions in SH-SY5Y cells. This might provide a plausible explanation for the underlying mechanisms of PM0.1 toxicity in neuronal cells and even the pathogenesis of diseases associated with its exposure. Copyright © 2016 John Wiley & Sons, Ltd.


Asunto(s)
Contaminantes Atmosféricos/toxicidad , Autofagia/efectos de los fármacos , Daño del ADN , Metales Pesados/toxicidad , Nanopartículas/toxicidad , Neuronas/efectos de los fármacos , Contaminantes Atmosféricos/química , Línea Celular , Supervivencia Celular/efectos de los fármacos , Ensayo Cometa , Humanos , Metales Pesados/química , Nanopartículas/química , Neuronas/metabolismo , Neuronas/patología , Tamaño de la Partícula , Especies Reactivas de Oxígeno/metabolismo , Solubilidad
5.
J Environ Biol ; 37(1): 1-5, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26930853

RESUMEN

The anti-obesity effect of Korean traditional food, Memilmuk, was examined through inhibition of differentiation of 3T3-L1 preadipocytes by buckwheat flour extract. Oil-Red O staining showed that lipid accumulation in adipocytes was reduced upon adding buckwheat flour extract, indicating effective inhibition of adipocyte differentiation. Buckwheat flour extract also inhibited the expression of adipogenic transcription factor, peroxisome proliferator-activated receptor γ (PPARγ), and AMP-activated protein kinase (AMPK), an intracellular regulator of energy balance. Overall, the anti-obesity effect of Korean Memilmuk might be mediated through down-regulation of PPARγ expression via AMPK activation by buckwheat flour.


Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Adipocitos/efectos de los fármacos , Fagopyrum/química , Alimentos Funcionales , Obesidad/tratamiento farmacológico , Células 3T3-L1 , Proteínas Quinasas Activadas por AMP/genética , Adipocitos/enzimología , Adipocitos/metabolismo , Animales , Supervivencia Celular , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Ratones , República de Corea
6.
J Neurol Sci ; 457: 122885, 2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38278691

RESUMEN

Amyotrophic Lateral Sclerosis (ALS) is the most common type of motor neuron disease characterized by progressive motor neuron degeneration in brain and spinal cord. Most cases are sporadic in ALS and 5-10% of cases are familiar. >50 genes are known to be associated with ALS and one of them is ERBB4. In this paper, we report the case of a 53-year-old ALS patient with progressive muscle weakness and fasciculation, but he had no cognitive decline. We performed the next generation sequencing (NGS) and in silico analysis, it predicted a highly pathogenic variant, c.2116 A > G, p.Asn706Asp (N706D) in the ERBB4 gene. The amino acid residue is highly conserved among species. ERBB4 is a member of the ERBB family of receptor tyrosine kinases. ERBB4 has multiple tyrosine phosphorylation sites, including an autophosphorylation site at tyrosine 1284 residue. Autophosphorylation of ERBB4 promotes biological activity and it associated with NRG-1/ERBB4 pathway. It is already known that tyrosine 128 phosphorylation of ERBB4 is decreased in patients who have ALS-associated ERBB4 mutations. We generated ERBB4 N706D construct using site-directed mutagenesis and checked the phosphorylation level of ERBB4 N706D in NSC-34 cells. We found that the phosphorylation of ERBB4 N706D was decreased compared to ERBB4 wild-type, indicating a loss of function mutation in ERBB4. We report a novel variant in ERBB4 gene leading to ALS through dysfunction of ERBB4.


Asunto(s)
Esclerosis Amiotrófica Lateral , Masculino , Humanos , Persona de Mediana Edad , Esclerosis Amiotrófica Lateral/metabolismo , Mutación/genética , Receptor ErbB-4/genética , Receptor ErbB-4/metabolismo , Tirosina
7.
J Environ Biol ; 34(2): 283-7, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24620593

RESUMEN

The aim of the study was to examine the liver tissue damage induced by nanosized-TiO2 in mouse. The biochemical parameters of liver, namely glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase and alkaline phosphatase were enhanced approximately 18%, 35% and 69% by exposure to nanosized-TiO2, respectively. The nanosized-TiO2 accumulated in the periphery of sinusoid in liver when the ultrastructure was examined through transmission electron microscopy. Enzymes, such as superoxide dismutase, catalase and aldehyde dehydrogenase were significantly inhibited by 22%, 38% and 15%, respectively, whereas glutathione peroxidase was constant following exposure to nanosized-TiO2.


Asunto(s)
Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Nanopartículas , Titanio/toxicidad , Animales , Masculino , Ratones , Ratones Endogámicos ICR , Titanio/química
8.
Front Aging Neurosci ; 15: 1047897, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36875699

RESUMEN

The endoplasmic reticulum (ER) is a major organelle involved in protein quality control and cellular homeostasis. ER stress results from structural and functional dysfunction of the organelle, along with the accumulation of misfolded proteins and changes in calcium homeostasis, it leads to ER stress response pathway such as unfolded protein response (UPR). Neurons are particularly sensitive to the accumulation of misfolded proteins. Thus, the ER stress is involved in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, prion disease and motor neuron disease (MND). Recently, the complex involvement of ER stress pathways has been demonstrated in experimental models of amyotrophic lateral sclerosis (ALS)/MND using pharmacological and genetic manipulation of the unfolded protein response (UPR), an adaptive response to ER stress. Here, we aim to provide recent evidence demonstrating that the ER stress pathway is an essential pathological mechanism of ALS. In addition, we also provide therapeutic strategies that can help treat diseases by targeting the ER stress pathway.

9.
PLoS One ; 17(4): e0266426, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35404971

RESUMEN

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic substantially undermined medical education and healthcare systems. Owing to the pandemic in South Korea, most medical schools needed to be flexible when conducting online and offline classes, but the guidelines did not reflect the specificity of medical schools. This study described the impact of modified anatomy education schedules at the Seoul National University College of Medicine (SNUCM) on students' academic performance and satisfaction. METHODS: Anatomy education in SNUCM is divided into three regional units (the upper and lower limbs, trunk, and head and neck). Owing to the COVID-19 pandemic, the schedule was mixed with simultaneous and rotating schedules. The authors conducted exceptions for online lectures, cadaver dissections, and written and practical examinations in three classes of approximately 50 students each. Furthermore, the authors assessed students' performance using three sets of written and practical examinations, and students completed a questionnaire regarding modified anatomy laboratory schedules. RESULTS: Despite the pandemic events in Seoul and South Korea during the laboratory sessions, all sessions were completed without any confirmed COVID-19 cases among the students, faculty, and staff. Most of the scores on the written and practical examinations significantly decreased in 2020 compared to those in 2019. However, in the trunk session that used the virtual anatomy application, the score on the practical examination in 2020 was significantly higher than that in 2019. Over 70% (79 and 77 out of 105 respondents on the upper and lower limbs and trunk, respectively) and 53% (55/105) students reported that there were no significant difficulties in studying anatomy in a face-to-face laboratory. CONCLUSIONS: In conclusion, an adequate education program for cadaver dissection should be developed and provided to overcome the pandemic restrictions. The study findings could serve as a reference for anatomy education during the COVID-19 pandemic.


Asunto(s)
Anatomía , COVID-19 , Educación a Distancia , Estudiantes de Medicina , Anatomía/educación , COVID-19/epidemiología , Cadáver , Humanos , Pandemias , República de Corea/epidemiología
10.
Dev Cell ; 57(6): 783-798.e8, 2022 03 28.
Artículo en Inglés | MEDLINE | ID: mdl-35320731

RESUMEN

Fused in sarcoma (FUS) is a DNA/RNA-binding protein that is involved in DNA repair and RNA processing. FUS is associated with neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, the molecular mechanisms underlying FUS-mediated neurodegeneration are largely unknown. Here, using a Drosophila model, we showed that the overexpression of glutathione transferase omega 2 (GstO2) reduces cytoplasmic FUS aggregates and prevents neurodegenerative phenotypes, including neurotoxicity and mitochondrial dysfunction. We found a FUS glutathionylation site at the 447th cysteine residue in the RanBP2-type ZnF domain. The glutathionylation of FUS induces FUS aggregation by promoting phase separation. GstO2 reduced cytoplasmic FUS aggregation by deglutathionylation in Drosophila brains. Moreover, we demonstrated that the overexpression of human GSTO1, the homolog of Drosophila GstO2, attenuates FUS-induced neurotoxicity and cytoplasmic FUS accumulation in mouse neuronal cells. Thus, the modulation of FUS glutathionylation might be a promising therapeutic strategy for FUS-associated neurodegenerative diseases.


Asunto(s)
Esclerosis Amiotrófica Lateral , Enfermedades Neurodegenerativas , Esclerosis Amiotrófica Lateral/genética , Esclerosis Amiotrófica Lateral/metabolismo , Animales , Drosophila/metabolismo , Ratones , Mutación/genética , Proteína FUS de Unión a ARN/química , Proteína FUS de Unión a ARN/genética , Proteína FUS de Unión a ARN/metabolismo
11.
J Appl Toxicol ; 31(1): 45-52, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20658469

RESUMEN

Exposure to airborne PM10, particulate matter with a median aerodynamic diameter of less than 10 µm, is known to be associated with a number of adverse health effects. To gain a better understanding of the cytotoxic mechanism and to develop protein biomarker candidates for PM10-induced toxicity, proteomic analyses were performed in human lung epithelial cells. Two-dimensional gel electrophoresis (2-DE) was followed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) to analyze the proteins differentially expressed by exposure to PM10. Analysis of 2-DE gels revealed more than 1270 protein spots in the cells, of which 36 showed changes of more than 2-fold on exposure to PM10 (up-regulation, n = 6; down-regulation, n = 30). The glycolytic enzyme pyruvate kinase, which also plays a role in tumor metabolism, showed a marked increase in expression, whereas the cytoskeleton-related vinculin and anti-inflammatory annexin 1 showed marked decreases in expression.


Asunto(s)
Células Epiteliales/metabolismo , Pulmón/metabolismo , Material Particulado/toxicidad , Proteínas/análisis , Proteómica/métodos , Biomarcadores , Línea Celular , Regulación hacia Abajo , Electroforesis en Gel Bidimensional/métodos , Humanos , Espectrometría de Masas , Proteínas/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Regulación hacia Arriba
12.
J Appl Toxicol ; 31(5): 463-70, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21491466

RESUMEN

Airborne nanoparticles with thermodynamic diameters less than 56 nm (PM(0.056)) were collected using a Moudi cascade impactor, and the differentially expressed proteins upon exposure to the airborne nanoparticles were identified in human bronchial epithelial cells. More than 600 protein spots were detected on the two-dimensional gel, and the identified 13 of these proteins showed notable changes. Nine were up-regulated and four were down-regulated following treatment with the airborne nanoparticles. Notably, malignant transformation-associated multiple forms of keratins, epigenetic regulation-related MBD1-containing chromatin associated factor 2, epithelial malignancy-related vimentin and exocytosis-related annexin A2 were changed upon exposure to airborne nanoparticle PM(0.056).


Asunto(s)
Contaminantes Atmosféricos/toxicidad , Bronquios/efectos de los fármacos , Nanopartículas/toxicidad , Proteómica , Mucosa Respiratoria/efectos de los fármacos , Contaminantes Atmosféricos/química , Anexina A2/genética , Anexina A2/metabolismo , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Western Blotting , Bronquios/metabolismo , Línea Celular , Supervivencia Celular/efectos de los fármacos , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Electroforesis en Gel Bidimensional/métodos , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Queratinas/genética , Queratinas/metabolismo , Metales Pesados/análisis , Nanopartículas/química , Mucosa Respiratoria/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Vimentina/genética , Vimentina/metabolismo
13.
Exp Neurobiol ; 30(5): 341-355, 2021 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-34737239

RESUMEN

Sirtuin 3 (SIRT3), a well-known mitochondrial deacetylase, is involved in mitochondrial function and metabolism under various stress conditions. In this study, we found that the expression of SIRT3 was markedly increased by oxidative stress in dopaminergic neuronal cells. In addition, SIRT3 overexpression enhanced mitochondrial activity in differentiated SH-SY5Y cells. We also showed that SIRT3 overexpression attenuated rotenoneor H2O2-induced toxicity in differentiated SH-SY5Y cells (human dopaminergic cell line). We further found that knockdown of SIRT3 enhanced rotenone- or H2O2-induced toxicity in differentiated SH-SY5Y cells. Moreover, overexpression of SIRT3 mitigated cell death caused by LPS/IFN-γ stimulation in astrocytes. We also found that the rotenone treatment increases the level of SIRT3 in Drosophila brain. We observed that downregulation of sirt2 (Drosophila homologue of SIRT3) significantly accelerated the rotenone-induced toxicity in flies. Taken together, these findings suggest that the overexpression of SIRT3 mitigates oxidative stress-induced cell death and mitochondrial dysfunction in dopaminergic neurons and astrocytes.

14.
Antioxidants (Basel) ; 11(1)2021 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-35052586

RESUMEN

TAR DNA-binding protein 43 (TDP-43) is a member of an evolutionarily conserved family of heterogeneous nuclear ribonucleoproteins that modulate multiple steps in RNA metabolic processes. Cytoplasmic aggregation of TDP-43 in affected neurons is a pathological hallmark of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), Alzheimer's disease (AD), and limbic predominant age-related TDP-43 encephalopathy (LATE). Mislocalized and accumulated TDP-43 in the cytoplasm induces mitochondrial dysfunction and reactive oxidative species (ROS) production. Here, we show that TDP-43- and rotenone-induced neurotoxicity in the human neuronal cell line SH-SY5Y were attenuated by hydroxocobalamin (Hb, vitamin B12 analog) treatment. Although Hb did not affect the cytoplasmic accumulation of TDP-43, Hb attenuated TDP-43-induced toxicity by reducing oxidative stress and mitochondrial dysfunction. Moreover, a shortened lifespan and motility defects in TDP-43-expressing Drosophila were significantly mitigated by dietary treatment with hydroxocobalamin. Taken together, these findings suggest that oral intake of hydroxocobalamin may be a potential therapeutic intervention for TDP-43-associated proteinopathies.

15.
Front Pharmacol ; 12: 747975, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34925009

RESUMEN

The autophagy-lysosomal pathway is an essential cellular mechanism that degrades aggregated proteins and damaged cellular components to maintain cellular homeostasis. Here, we identified HEXA-018, a novel compound containing a catechol derivative structure, as a novel inducer of autophagy. HEXA-018 increased the LC3-I/II ratio, which indicates activation of autophagy. Consistent with this result, HEXA-018 effectively increased the numbers of autophagosomes and autolysosomes in neuronal cells. We also found that the activation of autophagy by HEXA-018 is mediated by the AMPK-ULK1 pathway in an mTOR-independent manner. We further showed that ubiquitin proteasome system impairment- or oxidative stress-induced neurotoxicity was significantly reduced by HEXA-018 treatment. Moreover, oxidative stress-induced mitochondrial dysfunction was strongly ameliorated by HEXA-018 treatment. In addition, we investigated the efficacy of HEXA-018 in models of TDP-43 proteinopathy. HEXA-018 treatment mitigated TDP-43 toxicity in cultured neuronal cell lines and Drosophila. Our data indicate that HEXA-018 could be a new drug candidate for TDP-43-associated neurodegenerative diseases.

16.
Front Cell Dev Biol ; 8: 548283, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33262983

RESUMEN

The abnormal accumulation of alpha-synuclein (α-syn) aggregates in neurons and glial cells is widely known to be associated with many neurodegenerative diseases, including Parkinson's disease (PD), Dementia with Lewy bodies (DLB), and Multiple system atrophy (MSA). Mitochondrial dysfunction in neurons and glia is known as a key feature of α-syn toxicity. Studies aimed at understanding α-syn-induced toxicity and its role in neurodegenerative diseases have primarily focused on neurons. However, a growing body of evidence demonstrates that glial cells such as microglia and astrocytes have been implicated in the initial pathogenesis and the progression of α-Synucleinopathy. Glial cells are important for supporting neuronal survival, synaptic functions, and local immunity. Furthermore, recent studies highlight the role of mitochondrial metabolism in the normal function of glial cells. In this work, we review the complex relationship between glial mitochondria and α-syn-mediated neurodegeneration, which may provide novel insights into the roles of glial cells in α-syn-associated neurodegenerative diseases.

17.
Exp Mol Med ; 52(10): 1652-1662, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-33051572

RESUMEN

TAR DNA-binding protein 43 (TDP-43) is a highly conserved nuclear RNA/DNA-binding protein involved in the regulation of RNA processing. The accumulation of TDP-43 aggregates in the central nervous system is a common feature of many neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), Alzheimer's disease (AD), and limbic predominant age-related TDP-43 encephalopathy (LATE). Accumulating evidence suggests that prion-like spreading of aberrant protein aggregates composed of tau, amyloid-ß, and α-synuclein is involved in the progression of neurodegenerative diseases such as AD and PD. Similar to those of prion-like proteins, pathological aggregates of TDP-43 can be transferred from cell-to-cell in a seed-dependent and self-templating manner. Here, we review clinical and experimental studies supporting the prion-like spreading of misfolded TDP-43 and discuss the molecular mechanisms underlying the propagation of these pathological aggregated proteins. The idea that misfolded TDP-43 spreads in a prion-like manner between cells may guide novel therapeutic strategies for TDP-43-associated neurodegenerative diseases.


Asunto(s)
Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Susceptibilidad a Enfermedades , Enfermedades Neurodegenerativas/etiología , Enfermedades Neurodegenerativas/metabolismo , Animales , Proteínas de Unión al ADN/química , Regulación de la Expresión Génica , Humanos , Agregación Patológica de Proteínas , Unión Proteica , Relación Estructura-Actividad
18.
Front Cell Dev Biol ; 8: 581942, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33282865

RESUMEN

Transactive response DNA-binding protein 43 (TDP-43)-induced neurotoxicity is currently well recognized as a contributor to the pathology of amyotrophic lateral sclerosis (ALS), and the deposition of TDP-43 has been linked to other neurodegenerative diseases, such as frontotemporal lobar degeneration (FTLD) and Alzheimer's disease (AD). Recent studies also suggest that TDP-43-induced neurotoxicity is associated with ubiquitin-proteasome system (UPS) impairment. Histone deacetylase 6 (HDAC6) is a well-known cytosolic deacetylase enzyme that suppresses the toxicity of UPS impairment. However, the role of HDAC6 in TDP-43-induced neurodegeneration is largely unknown. In this study, we found that HDAC6 overexpression decreased the levels of insoluble and cytosolic TDP-43 protein in TDP-43-overexpressing N2a cells. In addition, TDP-43 overexpression upregulated HDAC6 protein and mRNA levels, and knockdown of Hdac6 elevated the total protein level of TDP-43. We further found that HDAC6 modulates TDP-43-induced UPS impairment via the autophagy-lysosome pathway (ALP). We also showed that TDP-43 promoted a short lifespan in flies and that the accumulation of ubiquitin aggregates and climbing defects were significantly rescued by overexpression of HDAC6 in flies. Taken together, these findings suggest that HDAC6 overexpression can mitigate neuronal toxicity caused by TDP-43-induced UPS impairment, which may represent a novel therapeutic approach for ALS.

19.
Elife ; 92020 12 11.
Artículo en Inglés | MEDLINE | ID: mdl-33305734

RESUMEN

Cytoplasmic accumulation of TDP-43 in motor neurons is the most prominent pathological feature in amyotrophic lateral sclerosis (ALS). A feedback cycle between nucleocytoplasmic transport (NCT) defect and TDP-43 aggregation was shown to contribute to accumulation of TDP-43 in the cytoplasm. However, little is known about cellular factors that can control the activity of NCT, thereby affecting TDP-43 accumulation in the cytoplasm. Here, we identified via FRAP and optogenetics cytosolic calcium as a key cellular factor controlling NCT of TDP-43. Dynamic and reversible changes in TDP-43 localization were observed in Drosophila sensory neurons during development. Genetic and immunohistochemical analyses identified the cytosolic calcium-Calpain-A-Importin α3 pathway as a regulatory mechanism underlying NCT of TDP-43. In C9orf72 ALS fly models, upregulation of the pathway activity by increasing cytosolic calcium reduced cytoplasmic accumulation of TDP-43 and mitigated behavioral defects. Together, these results suggest the calcium-Calpain-A-Importin α3 pathway as a potential therapeutic target of ALS.


Asunto(s)
Calcio/metabolismo , Calpaína/metabolismo , Citoplasma/metabolismo , Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila/metabolismo , alfa Carioferinas/metabolismo , Transporte Activo de Núcleo Celular/fisiología , Esclerosis Amiotrófica Lateral/metabolismo , Animales , Drosophila melanogaster , Neuronas/metabolismo
20.
Autophagy ; 16(8): 1396-1412, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-31690171

RESUMEN

TARDBP/TDP-43 (TAR DNA binding protein) proteinopathies are a common feature in a variety of neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), and Alzheimer disease (AD). However, the molecular mechanisms underlying TARDBP-induced neurotoxicity are largely unknown. In this study, we demonstrated that TARDBP proteinopathies induce impairment in the ubiquitin proteasome system (UPS), as evidenced by an accumulation of ubiquitinated proteins and a reduction in proteasome activity in neuronal cells. Through kinase inhibitor screening, we identified PTK2/FAK (PTK2 protein tyrosine kinase 2) as a suppressor of neurotoxicity induced by UPS impairment. Importantly, PTK2 inhibition significantly reduced ubiquitin aggregates and attenuated TARDBP-induced cytotoxicity in a Drosophila model of TARDBP proteinopathies. We further identified that phosphorylation of SQSTM1/p62 (sequestosome 1) at S403 (p-SQSTM1 [S403]), a key component in the autophagic degradation of poly-ubiquitinated proteins, is increased upon TARDBP overexpression and is dependent on the activation of PTK2 in neuronal cells. Moreover, expressing a non-phosphorylated form of SQSTM1 (SQSTM1S403A) significantly repressed the accumulation of insoluble poly-ubiquitinated proteins and neurotoxicity induced by TARDBP overexpression in neuronal cells. In addition, TBK1 (TANK binding kinase 1), a kinase that phosphorylates S403 of SQSTM1, was found to be involved in the PTK2-mediated phosphorylation of SQSTM1. Taken together, our data suggest that the PTK2-TBK1-SQSTM1 axis plays a critical role in the pathogenesis of TARDBP by regulating neurotoxicity induced by UPS impairment. Therefore, targeting the PTK2-TBK1-SQSTM1 axis may represent a novel therapeutic intervention for neurodegenerative diseases with TARDBP proteinopathies.Abbreviations: ALP: macroautophagy/autophagy lysosomal pathway; ALS: amyotrophic lateral sclerosis; ATXN2: ataxin 2; BafA1: bafilomycin A1; cCASP3: cleaved caspase 3; CSNK2: casein kinase 2; FTLD: frontotemporal lobar degeneration; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; OPTN: optineurin; PTK2/FAK: PTK2 protein tyrosine kinase 2; SQSTM1/p62: sequestosome 1; TARDBP/TDP-43: TAR DNA binding protein; TBK1: TANK binding kinase 1; ULK1: unc-51 like autophagy activating kinase 1; UPS: ubiquitin-proteasome system.


Asunto(s)
Quinasa 1 de Adhesión Focal/metabolismo , Proteína Sequestosoma-1/metabolismo , Proteinopatías TDP-43/metabolismo , Respuesta de Proteína Desplegada , Animales , Autofagia/efectos de los fármacos , Conducta Animal/efectos de los fármacos , Proteínas de Unión al ADN/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Drosophila melanogaster/metabolismo , Quinasa 1 de Adhesión Focal/antagonistas & inhibidores , Quinasa 1 de Adhesión Focal/genética , Ratones , Modelos Biológicos , Mutación/genética , Neurotoxinas/toxicidad , Fosforilación/efectos de los fármacos , Fosfoserina/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Solubilidad , Proteínas Ubiquitinadas/metabolismo , Respuesta de Proteína Desplegada/efectos de los fármacos
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