RESUMO
Mechanically activated Piezo1 channels undergo transitions from closed to open-state in response to pressure and other mechanical stimuli. However, the molecular details of these mechanosensitive gating transitions are unknown. Here, we used cell-attached pressure-clamp recordings to acquire single channel data at steady-state conditions (where inactivation has settled down), at various pressures and voltages. Importantly, we identify and analyze subconductance states of the channel which were not reported before. Pressure-dependent activation of Piezo1 increases the occupancy of open and subconductance state at the expense of decreased occupancy of shut-states. No significant change in the mean open time of subconductance states was observed with increasing negative pipette pressure or with varying voltages (ranging from -40 to -100 mV). Using Markov-chain modeling, we identified a minimal four-states kinetic scheme, which recapitulates essential characteristics of the single channel data, including that of the subconductance level. This study advances our understanding of Piezo1-gating mechanism in response to discrete stimuli (such as pressure and voltage) and paves the path to develop cellular and tissue level models to predict Piezo1 function in various cell types.
Assuntos
Ativação do Canal Iônico , Canais Iônicos , Mecanotransdução Celular , Pressão , Humanos , Células HEK293 , Ativação do Canal Iônico/fisiologia , Canais Iônicos/metabolismo , Cinética , Cadeias de MarkovRESUMO
Stroke results in varying levels of motor and sensory disability that have been linked to the neurodegeneration and neuroinflammation that occur in the infarct and peri-infarct regions within the brain. Specifically, previous research has identified a key role of the corticospinal tract in motor dysfunction and motor recovery post-stroke. Of note, neuroimaging studies have utilized magnetic resonance imaging (MRI) of the brain to describe the timeline of neurodegeneration of the corticospinal tract in tandem with motor function following a stroke. However, research has suggested that alternate motor pathways may also underlie disease progression and the degree of functional recovery post-stroke. Here, we assert that expanding neuroimaging techniques beyond the brain could expand our knowledge of alternate motor pathway structure post-stroke. In the present work, we will highlight findings that suggest that alternate motor pathways contribute to post-stroke motor dysfunction and recovery, such as the reticulospinal and rubrospinal tract. Then we review imaging and electrophysiological techniques that evaluate alternate motor pathways in populations of stroke and other neurodegenerative disorders. We will then outline and describe spinal cord neuroimaging techniques being used in other neurodegenerative disorders that may provide insight into alternate motor pathways post-stroke.
RESUMO
Toxicological studies have revealed that DEHP exposure during pregnancy may induce developmental disorders, especially in male offspring, leading to morphological and functional alterations in the reproductive system by mechanisms that should be investigated. Thus, the aim of this work was to analyze the testicular toxicity induced by an environmentally relevant DEHP dose during development and its impact on FLNA, a protein that participates in the blood-testis barrier assembly. We used male Wistar rats exposed to DEHP during pregnancy and lactation. The results showed that DEHP exposure during development and lactation increased body weight, decreased gonadal weight and shortened anogenital distance. This phthalate induced morphological changes in the testis, suggestive of hypospermatogenesis. DEHP exposure decreased the number of FLNA positive cells and the expression of FLNA and claudin-1 in prepubertal testes. Furthermore, DEHP inhibited FLNA and claudin-1 protein expression in adult male rats. These results indicated that exposure to DEHP during gestation and lactation perturbed testis development and suggested that FLNA is a target protein of DEHP, possibly contributing to the phthalate-induced damage on BTB.
Assuntos
Dietilexilftalato , Efeitos Tardios da Exposição Pré-Natal , Gravidez , Feminino , Ratos , Masculino , Animais , Humanos , Testículo/metabolismo , Dietilexilftalato/toxicidade , Dietilexilftalato/metabolismo , Filaminas/metabolismo , Claudina-1/metabolismo , Ratos Wistar , Lactação , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Efeitos Tardios da Exposição Pré-Natal/metabolismoRESUMO
Cancer cells almost universally harbor constitutively active Phosphatidylinositol-3 Kinase (PI3K) Pathway activity via mutation of key signaling components and/or epigenetic mechanisms. Scores of PI3K Pathway inhibitors are currently under investigation as putative chemotherapeutics. However, feedback and stem cell mechanisms induced by PI3K Pathway inhibition can lead to reduced treatment efficacy. To address therapeutic barriers, we examined whether JAKi would reduce stem gene expression in a setting of PI3K Pathway inhibition in order to improve treatment efficacy. We targeted the PI3K Pathway with NVP-BEZ235 (dual PI3K and mTOR inhibitor) in combination with the Janus Kinase inhibitor JAKi in glioblastoma (GBM) and basal-like breast cancer (BBC) cell lines. We examined growth, gene expression, and apoptosis in cells treated with NVP-BEZ235 and/or JAKi. Growth and recovery assays showed no significant impact of dual treatment with NVP-BEZ235/JAKi compared to NVP-BEZ235 treatment alone. Gene expression and flow cytometry revealed that single and dual treatments induced apoptosis. Stem gene expression was retained in dual NVP-BEZ235/JAKi treatment samples. Future in vivo studies may give further insight into the impact of combined NVP-BEZ235/JAKi treatment in GBM and BBC.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Neoplasias da Mama/tratamento farmacológico , Glioblastoma/tratamento farmacológico , Imidazóis/farmacologia , Quinolinas/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Apoptose/efeitos dos fármacos , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Glioblastoma/patologia , Humanos , Imidazóis/uso terapêutico , Inibidores de Janus Quinases/farmacologia , Inibidores de Janus Quinases/uso terapêutico , Inibidores de Fosfoinositídeo-3 Quinase/farmacologia , Inibidores de Fosfoinositídeo-3 Quinase/uso terapêutico , Quinolinas/uso terapêutico , Serina-Treonina Quinases TOR/antagonistas & inibidoresRESUMO
BACKGROUND: The PI3K pathway controls diverse cellular processes including growth, survival, metabolism, and apoptosis. Nuclear FOXO factors were observed in cancers that harbor constitutively active PI3K pathway output and stem signatures. FOXO1 and FOXO3 were previously published to induce stem genes such as OCT4 in embryonic stem cells. Here, we investigated FOXO-driven stem gene expression in U87MG glioblastoma cells. METHODS: PI3K-activated cancer cell lines were investigated for changes in gene expression, signal transduction, and clonogenicity under conditions with FOXO3 disruption or exogenous expression. The impact of PI3K pathway inhibition on stem gene expression was examined in a set of glioblastoma cell lines. RESULTS: We found that CRISPR-Cas9-mediated FOXO3 disruption in U87MG cells caused decreased OCT4 and SOX2 gene expression, STAT3 phosphorylation on tyrosine 705 and clonogenicity. FOXO3 over expression led to increased OCT4 in numerous glioblastoma cancer cell lines. Strikingly, treatment of glioblastoma cells with NVP-BEZ235 (a dual inhibitor of PI3K and mTOR), which activates FOXO factors, led to robust increases OCT4 gene expression. Direct FOXO factor recruitment to the OCT4 promoter was detected by chromatin immunoprecipitation analyses using U87MG extracts. DISCUSSION: We show for the first time that FOXO transcription factors promote stem gene expression glioblastoma cells. Treatment with PI3K inhibitor NVP-BEZ235 led to dramatic increases in stem genes in a set of glioblastoma cell lines. CONCLUSION: Given that, PI3K inhibitors are actively investigated as targeted cancer therapies, the FOXO-mediated induction of stem genes observed in this study highlights a potential hazard to PI3K inhibition. Understanding the molecular underpinnings of stem signatures in cancer will allow refinements to therapeutic strategies. Targeting FOXO factors to reduce stem cell characteristics in concert with PI3K inhibition may prove therapeutically efficacious.
Assuntos
Proteína Forkhead Box O3/metabolismo , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/patologia , Fosfatidilinositol 3-Quinases/metabolismo , Linhagem Celular Tumoral , HumanosRESUMO
CRISPR Cas9 genome editing allows researchers to modify genes in a multitude of ways including to obtain deletions, epitope-tagged loci, and knock-in mutations. Within 6 years of its initial application, CRISPR-Cas9 genome editing has been widely employed, but disadvantages to this method, such as low modification efficiencies and off-target effects, need careful consideration. Obtaining custom donor vectors can also be expensive and time-consuming. This chapter details strategies to overcome barriers to CRISPR-Cas9 genome editing as well as recent developments in employing this technique.
Assuntos
Sistemas CRISPR-Cas , Edição de Genes/métodos , Proteína 9 Associada à CRISPR/genética , Linhagem Celular , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Proteína Forkhead Box O3/genética , Vetores Genéticos/genética , Humanos , Mutação , RNA Guia de Cinetoplastídeos/genéticaRESUMO
The current study presents the adaptation of Automated Working Memory Assessment into European Spanish, considering the need of calibration for accent and linguistic issues not supported by the version available. For this purpose, verbal material was carefully and properly selected, considering specificities of the European Spanish, in order to control possible effects of psycholinguistic factors, such as word length or lexical frequency, and technical aspects such as stimuli presentation speed and sound quality were also tuned. An exploratory sample of 81 children from 7- to 9-year-old was assessed to confirm that the adaptation is suitable for further use, besides, their scores were contrasted with the Argentinean children. The data showed proper validity and reliability scores, which characterize this version as a useful instrument for research purposes, and its usage in further studies should be encourage to gather normative data for Spaniards
En el presente estudio se presenta la adaptación al idioma Español Europeo de la Evaluación Automatizada de la Memoria Operativa, habiéndose tenido en cuenta la necesidad de calibración para cuestiones de acento y lingüística que no son compatibles con la versión disponible. Con este propósito, el material verbal fue seleccionado cuidadosa y apropiadamente, teniendo en cuenta las especificidades del Español Europeo y con el fin de controlar los posibles efectos de los factores psicolingüísticos, tales como la longitud de las palabras o la frecuencia léxica, y aspectos técnicos, como la velocidad de presentación de los estímulos y la calidad de sonido también fueron controlados. Una muestra exploratoria de 81 niños de 7 a 9 años de edad se evaluó para confirmar que la adaptación es adecuada para su empleo posterior. Además las puntuaciones obtenidas se contrastaron con las de niños argentinos. Los datos mostraron una validez adecuada y una puntuación fiable, lo que permite considerar a esta versión como un instrumento útil para fines de investigación, y su empleo en futuros estudios debería incentivar la recopilación de datos normativos para españoles