Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
Proc Natl Acad Sci U S A ; 118(33)2021 08 17.
Artículo en Inglés | MEDLINE | ID: mdl-34389674

RESUMEN

Astrocytes have emerged as a potential source for new neurons in the adult mammalian brain. In mice, adult striatal neurogenesis can be stimulated by local damage, which recruits striatal astrocytes into a neurogenic program by suppression of active Notch signaling (J. P. Magnusson et al., Science 346, 237-241 [2014]). Here, we induced adult striatal neurogenesis in the intact mouse brain by the inhibition of Notch signaling in astrocytes. We show that most striatal astrocyte-derived neurons are confined to the anterior medial striatum, do not express established striatal neuronal markers, and exhibit dendritic spines, which are atypical for striatal interneurons. In contrast to striatal neurons generated during development, which are GABAergic or cholinergic, most adult astrocyte-derived striatal neurons possess distinct electrophysiological properties, constituting the only glutamatergic striatal population. Astrocyte-derived neurons integrate into the adult striatal microcircuitry, both receiving and providing synaptic input. The glutamatergic nature of these neurons has the potential to provide excitatory input to the striatal circuitry and may represent an efficient strategy to compensate for reduced neuronal activity caused by aging or lesion-induced neuronal loss.


Asunto(s)
Astrocitos/fisiología , Conexina 30/metabolismo , Ácido Glutámico/metabolismo , Neuronas/fisiología , Animales , Diferenciación Celular , Conexina 30/genética , Desoxiuridina/análogos & derivados , Desoxiuridina/farmacología , Fenómenos Electrofisiológicos , Neuronas GABAérgicas/enzimología , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/fisiología , Interneuronas/enzimología , Proteínas Luminiscentes , Ratones , Ratones Transgénicos , Óxido Nítrico Sintasa de Tipo I/genética , Óxido Nítrico Sintasa de Tipo I/metabolismo , Recombinación Genética , Tamoxifeno/farmacología
2.
Liver Int ; 35(4): 1253-64, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25243526

RESUMEN

BACKGROUND & AIMS: Liver fibrosis is induced by the accumulation of extracellular matrix, deposited mainly by activated hepatic stellate cells (HSCs). One key characteristic of stellate cell activation is the directional migration to the site of injury during the wound-healing process. P311 is a protein that has been shown to play a role in migration and we aimed to study a possible role for this protein during stellate cell migration. METHODS: Mouse stellate cells were isolated and cultured in vitro to investigate P311 protein and gene expression during HSC activation by immunocytochemistry and RT-qPCR respectively. Expression of P311 during in vivo activation was evaluated in CCl4 and bile duct ligation-induced liver fibrosis. Production of reactive oxygen species was determined using the fluorescent probe DCFH-DA. By siRNA-mediated knockdown of P311, we investigated a possible effect on proliferation by incorporation of EdU and on migration by Boyden chamber assays. RESULTS: P311 gene expression was increased during both in vitro and in vivo activation of HSCs. siRNA-mediated knockdown led to a decrease in reactive oxygen production and cell proliferation. Migration induced by different chemokines, such as PDGF-bb and MCP-1 was inhibited by knockdown of P311. CONCLUSIONS: P311 is central to reactive oxygen species-mediated HSC migration induced by different chemokines.


Asunto(s)
Movimiento Celular , Células Estrelladas Hepáticas/metabolismo , Cirrosis Hepática Experimental/metabolismo , Hígado/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Animales , Becaplermina , Movimiento Celular/efectos de los fármacos , Proliferación Celular , Células Cultivadas , Quimiocina CCL2/farmacología , Regulación de la Expresión Génica , Hemo-Oxigenasa 1/genética , Hemo-Oxigenasa 1/metabolismo , Células Estrelladas Hepáticas/efectos de los fármacos , Células Estrelladas Hepáticas/patología , Hígado/efectos de los fármacos , Hígado/patología , Cirrosis Hepática Experimental/genética , Cirrosis Hepática Experimental/patología , Masculino , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones Endogámicos BALB C , Proteínas del Tejido Nervioso/genética , Estrés Oxidativo , Proteínas Proto-Oncogénicas c-sis/farmacología , Interferencia de ARN , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal , Factores de Tiempo , Transfección , Factor de Crecimiento Transformador beta/farmacología
3.
Eur J Gastroenterol Hepatol ; 24(12): 1370-80, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22895388

RESUMEN

AIM: Direct and indirect effects of leptin on hepatic stellate cells (HSCs) have been documented in the literature, whereas little is known about leptin's actions on hepatocytes. Leptin mediates its profibrogenic and proinflammatory effects on HSCs in part through the production of intracellular reactive oxygen species (ROS). In this study, we focus our analysis on leptin-induced ROS production in hepatocytes. METHODS: The expression of leptin receptor isoforms on primary mouse liver cells was examined by real-time quantitative-PCR and western blotting. Cultures were exposed to leptin in combination with inhibitors for reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, MAP kinase/ERK kinase 1 (MEK1) or janus kinase 2 (JAK2). ROS levels were quantified by measuring fluorescence. The effects of leptin on hepatocyte functions and programmed cell death were evaluated by fluorescent or luminescent assays. RESULTS: Leptin induced ROS production in primary hepatocytes by 150-450%, compared with a 20-30% increase in HSCs and liver sinusoidal endothelial cells (LSECs). This ROS production could be inhibited by NADPH oxidase, MEK1 and JAK2 inhibitors. Western blotting indicated that mouse HSCs and LSECs mainly express short leptin receptor isoforms, whereas hepatocytes appeared to express both short and long isoform(s). Leptin-induced ROS production in db/db hepatocytes did not differ from wild-type mice. Finally, leptin had no negative influence on primary hepatocyte functions. CONCLUSION: Leptin induced higher ROS levels in primary hepatocytes than in LSECs and HSCs, depending on NADPH oxidase, MEK1 and JAK2 signalling but not on the long leptin receptor isoform. Furthermore, leptin exposure did not influence primary hepatocyte functionality negatively.


Asunto(s)
Hepatocitos/metabolismo , Leptina/metabolismo , Estrés Oxidativo , Especies Reactivas de Oxígeno/metabolismo , Albúminas/metabolismo , Animales , Apoptosis , Western Blotting , Células Cultivadas , Citocromo P-450 CYP1A2/metabolismo , Inhibidores Enzimáticos/farmacología , Hemo-Oxigenasa 1/genética , Hemo-Oxigenasa 1/metabolismo , Hepatocitos/efectos de los fármacos , Hepatocitos/patología , Janus Quinasa 2/antagonistas & inhibidores , Janus Quinasa 2/metabolismo , MAP Quinasa Quinasa 1/antagonistas & inhibidores , MAP Quinasa Quinasa 1/metabolismo , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , NADPH Oxidasas/antagonistas & inhibidores , NADPH Oxidasas/metabolismo , Estrés Oxidativo/efectos de los fármacos , Isoformas de Proteínas , ARN Mensajero/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores de Leptina/genética , Receptores de Leptina/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal , Factores de Tiempo , Urea/metabolismo
4.
BMC Gastroenterol ; 12: 68, 2012 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-22686625

RESUMEN

BACKGROUND: Mitochondrial dysfunction participates in the progression of several pathologies. Although there is increasing evidence for a mitochondrial role in liver disease, little is known about its contribution to hepatic stellate cell (HSC) activation. In this study we investigated the role of mitochondrial activity through mild uncoupling during in vitro activation of HSCs. METHODS: Cultured primary human and mouse HSCs were treated with the chemical uncouplers FCCP and Valinomycin. ATP levels were measured by luciferase assay and production of reactive oxygen species was determined using the fluorescent probe DCFH-DA. Possible cytotoxicity by uncoupler treatment was evaluated by caspase 3/7 activity and cytoplasmic protease leakage. Activation of HSCs and their response to the pro-fibrogenic cytokine TGF-ß was evaluated by gene expression of activation markers and signal mediators using RT-qPCR. Proliferation was measured by incorporation of EdU and protein expression of α-smooth muscle actin was analyzed by immunocytochemistry and western blot. RESULTS: FCCP and Valinomycin treatment mildly decreased ATP and reactive oxygen species levels. Both uncouplers increased the expression of mitochondrial genes such as Tfam and COXIV while inducing morphological features of quiescent mouse HSCs and abrogating TGF-ß signal transduction. Mild uncoupling reduced HSC proliferation and expression of pro-fibrogenic markers of mouse and human HSCs. CONCLUSIONS: Mild mitochondrial uncoupling inhibits culture-induced HSC activation and their response to pro-fibrogenic cytokines like TGF-ß. These results therefore suggest mitochondrial uncoupling of HSCs as a strategy to reduce progression of liver fibrosis.


Asunto(s)
Carbonil Cianuro p-Trifluorometoxifenil Hidrazona/farmacología , Proliferación Celular/efectos de los fármacos , Células Estrelladas Hepáticas/efectos de los fármacos , Mitocondrias Hepáticas/efectos de los fármacos , Desacopladores/farmacología , Valinomicina/farmacología , Actinas/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Caspasa 3/metabolismo , Caspasa 7/metabolismo , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Células Cultivadas , Células Estrelladas Hepáticas/citología , Células Estrelladas Hepáticas/metabolismo , Humanos , Técnicas In Vitro , Masculino , Ratones , Mitocondrias Hepáticas/fisiología , Modelos Animales , Especies Reactivas de Oxígeno/metabolismo
5.
Autophagy ; 8(1): 126-8, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22082960

RESUMEN

Hepatic stellate cell (HSC) activation, the transition from a resident quiescent HSC to a myofibroblastic collagen-producing HSC, is a fundamental feature of liver fibrosis. Autophagy has been implicated in major liver pathologies, such as HCV infection and hepatocarcinoma. However, its role in HSC biology is largely unknown. Recently, we were able to demonstrate that HSC activation is followed by an increased autophagic flux and that its inhibition can partially inhibit the HSC myofibroblastic transition. These results point to autophagy as a possible target in the prevention of HSC activation.


Asunto(s)
Autofagia , Células Estrelladas Hepáticas/patología , Animales , Humanos , Ratones , Modelos Biológicos , Ratas
6.
J Hepatol ; 55(6): 1353-60, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21803012

RESUMEN

BACKGROUND & AIMS: Autophagy is a metabolic process that degrades and recycles intracellular organelles and proteins with many connections to human disease and physiology. We studied the role of autophagy during hepatic stellate cell (HSC) activation, a key event in liver fibrogenesis. METHODS: Analysis of the autophagic flux during in vitro activation of primary mouse HSCs was performed using a DsRed-GFP-LC3B encoding plasmid. The effect of autophagy inhibition by bafilomycin A1 on the in vitro activation process of human and mouse HSCs was examined by measuring proliferation, presence of activation markers by RT-qPCR, immunofluorescence, and Western blotting. Analysis of lipid droplet and microtubule-associated protein light chain 3 beta (LC3B) colocalization in the presence of PDGF-BB was investigated by immunocytochemistry. RESULTS: A significant increased autophagic flux was observed during culture induced mouse HSC activation. Treatment of mouse HSCs and human HSCs with autophagy inhibitor bafilomycin A1 results in a significant decreased proliferation and expression of activation markers. In addition, lipid droplets and LC3B colocalization was increased after PDGF-BB treatment in quiescent HSCs. CONCLUSIONS: During HSC activation, autophagic flux is increased. The demonstration of partly inhibition of in vitro HSC activation after treatment with an autophagy inhibitor unveils a potential new therapeutic strategy for liver fibrosis.


Asunto(s)
Autofagia/fisiología , Células Estrelladas Hepáticas/fisiología , Actinas/genética , Animales , Autofagia/efectos de los fármacos , Becaplermina , Tetracloruro de Carbono/toxicidad , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Colágeno Tipo I/genética , Cadena alfa 1 del Colágeno Tipo I , Células Estrelladas Hepáticas/efectos de los fármacos , Células Estrelladas Hepáticas/patología , Humanos , Técnicas In Vitro , Metabolismo de los Lípidos/efectos de los fármacos , Cirrosis Hepática/etiología , Cirrosis Hepática/patología , Cirrosis Hepática/fisiopatología , Macrólidos/farmacología , Masculino , Ratones , Ratones Endogámicos BALB C , Proteínas Asociadas a Microtúbulos/metabolismo , Proteína-Lisina 6-Oxidasa , Proteínas Proto-Oncogénicas c-sis/metabolismo , Proteínas Proto-Oncogénicas c-sis/farmacología , ARN Mensajero/genética , ARN Mensajero/metabolismo
7.
J Hepatol ; 52(3): 389-97, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20133001

RESUMEN

BACKGROUND & AIMS: Advanced glycation end products are known to play an important role in the metabolic syndrome and were recently suggested to contribute to liver fibrosis development. However, little is known about the effect of advanced glycation end products on hepatic stellate cells, the major contributors to liver fibrosis development. We therefore studied the effect of advanced glycation end products on reactive oxygen species generation, a main feature for the activation hepatic stellate cells. METHODS: Three different types of advanced glycation end products were generated by BSA incubation with different substrates. The presence of advanced glycation end product receptors was examined by RTq-PCR, immunofluorescence and western blotting. Reactive oxygen species production was measured using DCFH-DA. RESULTS: Hepatic stellate cells express five advanced glycation end product receptors: Galectin-3, CD36, SR-AI, SR-BI and RAGE. All receptors, except SR-BI, showed up-regulation during HSC activation. All three advanced glycation end product types induced reactive oxygen species generation. DPI and NSC, a NADPH oxidase and a Rac1 inhibitor respectively, inhibited reactive oxygen species production. Rottlerin, a molecule often used as a PKCdelta inhibitor, also abrogated reactive oxygen species production. SiRNA mediated knockdown of p47(phox), Rac1 and PKCdelta decreased reactive oxygen species production induced by advanced glycation end products, establishing a role for these proteins in reactive oxygen species induction. CONCLUSIONS: The demonstration of advanced glycation end product-induced reactive oxygen species generation in hepatic stellate cells unveils a potential new route through which advanced glycation end products induce liver fibrosis in the metabolic syndrome.


Asunto(s)
Productos Finales de Glicación Avanzada/farmacología , Células Estrelladas Hepáticas/efectos de los fármacos , Células Estrelladas Hepáticas/metabolismo , NADPH Oxidasas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Animales , Células Cultivadas , Células Estrelladas Hepáticas/citología , Masculino , Ratones , Modelos Animales , Neuropéptidos/metabolismo , Proteína Quinasa C-delta/metabolismo , ARN Interferente Pequeño/farmacología , Receptor para Productos Finales de Glicación Avanzada , Receptores Inmunológicos/metabolismo , Transducción de Señal/efectos de los fármacos , Proteínas de Unión al GTP rac/metabolismo , Proteína de Unión al GTP rac1
8.
Life Sci ; 82(1-2): 21-9, 2008 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-18037449

RESUMEN

Hepatic stellate cells (HSC) play a crucial role in the development of liver fibrosis and are important targets in liver disease therapy. Adenosine acts as an extracellular signaling molecule in various tissues and in liver this nucleoside exerts protective effects. Ecto-5'-nucleotidase/CD73 is a marker for the plasma membrane and is considered to be a key enzyme in the generation of adenosine in the extracellular medium, by transforming AMP into adenosine. In addition, adenosine production from AMP is also catalyzed by alkaline phosphatase. We compared the extracellular metabolism of AMP and transcriptional levels of the ecto-5'-nucleotidase/CD73 and tissue non-specific alkaline phosphatase (TNALP) in activated and quiescent HSC of the mouse hepatic stellate cell line GRX. This cell line expresses a myofibroblast phenotype in basal medium and both retinol and indomethacin treatment induced a phenotypic change of GRX cells to quiescent HSC. Ecto-5'-nucleotidase activity and its mRNA expression were found to be higher in quiescent HSC than in activated HSC. During phenotype conversion, mediated by retinol, the AMP decay was accelerated with adenosine accumulation in extracellular medium, likely due to the decrease in adenosine deaminase activity also observed in quiescent HSC. The treatment with retinol also involves transcriptional activation of TNALP. Taken together, these data suggest that ecto-5'-nucleotidase-dependent adenosine generation may play a role in the regulation of quiescent HSC functions.


Asunto(s)
5'-Nucleotidasa , Adenosina/metabolismo , Cirrosis Hepática/enzimología , Hígado/enzimología , 5'-Nucleotidasa/biosíntesis , 5'-Nucleotidasa/metabolismo , Adenosina Monofosfato/metabolismo , Fosfatasa Alcalina/metabolismo , Animales , Línea Celular Transformada , Senescencia Celular , Activación Enzimática , Líquido Extracelular/metabolismo , Indometacina/farmacología , Hígado/patología , Cirrosis Hepática/patología , Ratones , Fenotipo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Vitamina A/farmacología
9.
Liver Int ; 27(9): 1255-64, 2007 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-17919238

RESUMEN

BACKGROUND/AIMS: Pre-adipocyte differentiation into adipocyte is a terminal differentiation process triggered by a cascade of transcription factors. Conversely, hepatic stellate cells (HSC) can switch between lipid storing and the myofibroblast phenotype in association with liver fibrotic processes. Here, adipogenic/lipogenic-related transcription factors and downstream-regulated genes were evaluated in a murine HSC cell line. GRX-HSC cells are transitional myofibroblasts that differentiate into lipocytes following retinol or indomethacin treatment. METHODS/RESULTS: Specific mRNAs were quantified by a real-time polymerase chain reaction after 24 h or 7 days of cell culture with indomethacin or retinol. Proliferator-activated receptorgamma and Pex16 transcripts were increased either by retinol or indomethacin. Retinol induced a minor increase in C/enhancer binding proteinalpha transcripts, while only indomethacin increased adipsin transcripts. CONCLUSIONS: Our results showed that the myofibroblast to lipocyte phenotype switch follows partially different transcriptional pathways, according to the effector. Retinol induces lipid synthesis and storage without affecting characteristic adipocytic genes, while indomethacin treatment restores the lipocytic phenotype with increased adipisin expression.


Asunto(s)
Adipocitos/citología , Adipocitos/metabolismo , Lipogénesis/fisiología , Hígado/citología , Proteínas de la Membrana/metabolismo , Factores de Transcripción/metabolismo , Adipocitos/efectos de los fármacos , Animales , Proteínas Potenciadoras de Unión a CCAAT/genética , Proteínas Potenciadoras de Unión a CCAAT/metabolismo , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Indometacina/farmacología , Proteínas de la Membrana/genética , Ratones , Miocardio/citología , Miocardio/metabolismo , PPAR gamma/genética , PPAR gamma/metabolismo , Fenotipo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Transcripción/genética , Transcripción Genética , Vitamina A/farmacología
10.
J Cell Biochem ; 90(2): 387-96, 2003 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-14505354

RESUMEN

Hepatic fibrosis is a common response to chronic liver injury and is characterized by increased production of extracellular matrix components, whose major part is produced by hepatic stellate cells activated by inflammatory mediators to proliferate and migrate into the injured regions. GRX cells are a model of hepatic stellate cells characterized as myofibroblasts by morphological and biochemical criteria. We have recently shown that they respond to inflammatory mediators and cytokines present in the concanavalin A-activated spleen cell supernatant (SCS) by quantitative changes in the expression of intermediate filaments. The present study investigated the effects of SCS and TNF-alpha on the GRX cell proliferation and on the organization of the actin cytoskeleton. SCS and TNF-alpha diminished the culture cell density, with an increase of cell [(3)H]thymidine incorporation and of cellular protein content, indicating an arrest in the G2/M phase of the cell cycle, which was reversible 48 h after removal of SCS. This effect was abrogated by dibutiryl-cAMP. Actin cytoskeleton reorganization was observed after 24 h treatment, indicating increased cell motility. Our results suggest that inflammation-dependent activation of stellate cells occurs in ordered interaction and coordination of proinflammatory agents. The increase of cAMP levels activates the conversion of lipocytes into myofibroblasts and increases the number of cells that can participate in repair. Since cAMP retains cells in the G1 phase, cytokines of the TNF-alpha group are required for cell proliferation inducing the entry into the S phase. The progression through the G2/M checkpoint is mediated again by increased cAMP levels.


Asunto(s)
Movimiento Celular , AMP Cíclico/metabolismo , Fase G2 , Hígado/citología , Mitosis , Actinas/metabolismo , Adipocitos/metabolismo , Animales , Antineoplásicos/farmacología , Bucladesina/farmacología , División Celular , Células Cultivadas , Citoesqueleto , Fibroblastos/citología , Fibroblastos/metabolismo , Técnicas In Vitro , Hígado/metabolismo , Ratones , Células Musculares/citología , Células Musculares/metabolismo , Bazo/metabolismo , Timidina/metabolismo , Factor de Necrosis Tumoral alfa/farmacología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...