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1.
J Infect Dis ; 226(5): 901-906, 2022 09 13.
Artículo en Inglés | MEDLINE | ID: mdl-35313340

RESUMEN

Human immunodeficiency virus (HIV) infection is associated with impaired natural killer (NK) cell activity, which is only incompletely restored under antiretroviral therapy. Analyzing the bioenergetics profiles of oxygen consumption, we observed that several parameters were significantly reduced in HIV+ NK cells, indicating a mitochondrial defect. Accordingly, we found HIV+ CD56bright NK cells to display a decreased mitochondrial membrane potential and mitochondrial mass. Both parameters were positively correlated with interferon gamma (IFN-γ) production of NK cells. Finally, we demonstrated that stimulation of HIV+ NK cells with MitoTEMPO, a mitochondria-targeting antioxidant, significantly improved IFN-γ production. We identified mitochondrial dysfunction as a mechanism that contributes to impaired NK cell function.


Asunto(s)
Infecciones por VIH , Antígeno CD56/metabolismo , Citocinas/metabolismo , VIH/metabolismo , Infecciones por VIH/complicaciones , Humanos , Células Asesinas Naturales/metabolismo , Mitocondrias/metabolismo
2.
Hum Mol Genet ; 26(4): 790-800, 2017 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-28040728

RESUMEN

A repeat expansion in the non-coding region of C9orf72 gene is the most common mutation causing frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Sense and antisense transcripts are translated into aggregating dipeptide repeat (DPR) proteins in all reading frames (poly-GA,-GP,-GR,-PA and -PR) through an unconventional mechanism. How these changes contribute to cytoplasmic mislocalization and aggregation of TDP-43 and thereby ultimately leading to neuron loss remains unclear. The repeat RNA itself and poly-GR/PR have been linked to impaired nucleocytoplasmic transport. Here, we show that compact cytoplasmic poly-GA aggregates impair nuclear import of a reporter containing the TDP-43 nuclear localization (NLS) signal. However, a reporter containing a non-classical PY-NLS was not affected. Moreover, poly-GA expression prevents TNFα induced nuclear translocation of p65 suggesting that poly-GA predominantly impairs the importin-α/ß-dependent pathway. In neurons, prolonged poly-GA expression induces partial mislocalization of TDP-43 into cytoplasmic granules. Rerouting poly-GA to the nucleus prevented TDP-43 mislocalization, suggesting a cytoplasmic mechanism. In rescue experiments, expression of importin-α (KPNA3, KPNA4) or nucleoporins (NUP54, NUP62) restores the nuclear localization of the TDP reporter. Taken together, inhibition of nuclear import of TDP-43 by cytoplasmic poly-GA inclusions causally links the two main aggregating proteins in C9orf72 ALS/FTLD pathogenesis.


Asunto(s)
Esclerosis Amiotrófica Lateral/metabolismo , Expansión de las Repeticiones de ADN , Proteínas de Unión al ADN/metabolismo , Degeneración Lobar Frontotemporal/metabolismo , Neuronas/metabolismo , Proteínas/metabolismo , Esclerosis Amiotrófica Lateral/genética , Esclerosis Amiotrófica Lateral/patología , Animales , Proteína C9orf72 , Proteínas de Unión al ADN/genética , Degeneración Lobar Frontotemporal/genética , Degeneración Lobar Frontotemporal/patología , Humanos , Cuerpos de Inclusión/genética , Cuerpos de Inclusión/metabolismo , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Señales de Localización Nuclear/genética , Señales de Localización Nuclear/metabolismo , Proteínas de Complejo Poro Nuclear/genética , Proteínas de Complejo Poro Nuclear/metabolismo , Proteínas/genética , Ratas , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismo , alfa Carioferinas/genética , alfa Carioferinas/metabolismo
3.
J Virol ; 89(19): 9853-64, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26202247

RESUMEN

UNLABELLED: Mammalian prions are unconventional infectious agents composed primarily of the misfolded aggregated host prion protein PrP, termed PrP(Sc). Prions propagate by the recruitment and conformational conversion of cellular prion protein into abnormal prion aggregates on the cell surface or along the endocytic pathway. Cellular glycosaminoglycans have been implicated as the first attachment sites for prions and cofactors for cellular prion replication. Glycosaminoglycan mimetics and obstruction of glycosaminoglycan sulfation affect prion replication, but the inhibitory effects on different strains and different stages of the cell infection have not been thoroughly addressed. We examined the effects of a glycosaminoglycan mimetic and undersulfation on cellular prion protein metabolism, prion uptake, and the establishment of productive infections in L929 cells by two mouse-adapted prion strains. Surprisingly, both treatments reduced endogenous sulfated glycosaminoglycans but had divergent effects on cellular PrP levels. Chemical or genetic manipulation of glycosaminoglycans did not prevent PrP(Sc) uptake, arguing against their roles as essential prion attachment sites. However, both treatments effectively antagonized de novo prion infection independently of the prion strain and reduced PrP(Sc) formation in chronically infected cells. Our results demonstrate that sulfated glycosaminoglycans are dispensable for prion internalization but play a pivotal role in persistently maintained PrP(Sc) formation independent of the prion strain. IMPORTANCE: Recently, glycosaminoglycans (GAGs) became the focus of neurodegenerative disease research as general attachment sites for cell invasion by pathogenic protein aggregates. GAGs influence amyloid formation in vitro. GAGs are also found in intra- and extracellular amyloid deposits. In light of the essential role GAGs play in proteinopathies, understanding the effects of GAGs on protein aggregation and aggregate dissemination is crucial for therapeutic intervention. Here, we show that GAGs are dispensable for prion uptake but play essential roles in downstream infection processes. GAG mimetics also affect cellular GAG levels and localization and thus might affect prion propagation by depleting intracellular cofactor pools.


Asunto(s)
Glicosaminoglicanos/metabolismo , Proteínas PrPSc/metabolismo , Enfermedades por Prión/fisiopatología , Animales , Transporte Biológico/fisiología , Western Blotting , Células CHO , Línea Celular , Cloratos , Cricetinae , Cricetulus , Sulfato de Dextran , Citometría de Flujo , Procesamiento de Imagen Asistido por Computador , Ratones , Ratones Endogámicos C57BL , Microscopía Confocal , Enfermedades por Prión/metabolismo , Estadísticas no Paramétricas
4.
J Cell Sci ; 125(Pt 1): 155-65, 2012 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-22250204

RESUMEN

The spatially ordered formation and disassembly of focal adhesions is a basic requirement for effective cell locomotion. Because focal adhesions couple the contractile actin-myosin network to the substrate, their distribution determines the pattern of traction forces propelling the cell in a certain direction. In the present study, we quantitatively analyzed the spatial patterning of cell-substrate adhesion in migrating cells by mapping averaged focal adhesion growth dynamics to a standardized cell coordinate system. These maps revealed distinct zones of focal adhesion assembly, disassembly and stability and were strongly interrelated with corresponding actin flow and traction force patterns. Moreover, the mapping technique enables precise detection of even minute responses of adhesion dynamics upon targeted signaling perturbations. For example, the partial inhibition of vinculin phosphorylation was followed by the reduced number of newly formed adhesions, whereas growth dynamics of existing adhesions remained unaffected.


Asunto(s)
Movimiento Celular , Forma de la Célula , Adhesiones Focales/metabolismo , Queratinocitos/citología , Queratinocitos/metabolismo , Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Polaridad Celular , Humanos , Fosforilación , Vinculina/metabolismo
5.
Differentiation ; 84(5): 366-70, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23142732

RESUMEN

Stem cell fate can be induced by the grade of stiffness of the extracellular matrix, depending on the developed tissue or complex tissues. For example, a rigid extracellular matrix induces the osteogenic differentiation in bone marrow derived mesenchymal stem cells (MSCs), while a softer surface induces the osteogenic differentiation in dental follicle cells (DFCs). To determine whether differentiation of ectomesenchymal dental precursor cells is supported by similar grades of extracellular matrices (ECMs) stiffness, we examined the influence of the surface stiffness on the proliferation and osteogenic differentiation of stem cells from human exfoliated deciduous teeth (SHED). Cell proliferation of SHED was significantly decreased on cell culture surfaces with a muscle-like stiffness. A dexamethasone-based differentiation medium induced the osteogenic differentiation of SHED on substrates of varying mechanical stiffness. Here, the hardest surface improved the induction of osteogenic differentiation in comparison to that with the softest stiffness. In conclusion, our study showed that the osteogenic differentiation of ectomesenchymal dental precursor cells SHED and DFCs are not supported by similar grades of ECM stiffness.


Asunto(s)
Diferenciación Celular , Matriz Extracelular/química , Osteogénesis , Células Madre/citología , Diente Primario/citología , Línea Celular , Saco Dental/citología , Dexametasona , Dureza , Humanos
6.
Biochem Biophys Res Commun ; 410(3): 587-92, 2011 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-21684253

RESUMEN

The differentiation of stem cells can be directed by the grade of stiffness of the developed tissue cells. For example a rigid extracellular matrix supports the osteogenic differentiation in bone marrow derived mesenchymal stem cells (MSCs). However, less is known about the relation of extracellular matrix stiffness and cell differentiation of ectomesenchymal dental precursor cells. Our study examined for the first time the influence of the surface stiffness on the proliferation and osteogenic differentiation of human dental follicle cells (DFCs). Cell proliferation of DFCs was only slightly decreased on cell culture surfaces with a bone-like stiffness. The osteogenic differentiation in DFCs could only be initiated with a dexamethasone based differentiation medium after using varying stiffness. Here, the softest surface improved the induction of osteogenic differentiation in comparison to that with the highest stiffness. In conclusion, different to bone marrow derived MSCs, soft ECMs have a superior capacity to support the osteogenic differentiation of DFCs.


Asunto(s)
Diferenciación Celular , Saco Dental/citología , Células Madre Mesenquimatosas/citología , Osteogénesis , Técnicas de Cultivo de Célula , Proliferación Celular , Células Cultivadas , Medios de Cultivo/farmacología , Saco Dental/efectos de los fármacos , Dexametasona/farmacología , Humanos , Masculino , Células Madre Mesenquimatosas/efectos de los fármacos , Propiedades de Superficie , Adulto Joven
7.
Eur J Immunol ; 39(12): 3447-58, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19830727

RESUMEN

NK cells, a heterogeneous sub-population of lymphocytes, are critically involved in the regulation of both innate and adaptive immune responses in humans. Besides their participation in the control of tumors and viral infections, they also regulate inflammatory processes, mediating both beneficial and detrimental effects. To effectively fulfil their role in immune surveillance, proper trafficking of NK cells is essential. However, the mechanisms and factors governing NK cell recruitment are only poorly dissected. Here, we describe the functional role of tetraspanins, a family of evolutionary conserved cell-surface proteins, in modulating migration and transmigration of human NK cells. We demonstrate expression of various tetraspanins on NK cells. Furthermore, we show that stimulation of the NK cell-expressed tetraspanin CD81 induces phosphorylation of ezrin/radixin/moesin proteins and leads to NK cell polarization thereby facilitating NK cell migration toward various chemokines/cytokines. Finally, we provide evidence for a role of CD81 in promoting adhesion of NK cells to components of the extracellular matrix, a prerequisite for extravasation of lymphocytes in inflamed tissues. Thus, our data suggest that the tetraspanin CD81 is importantly involved in the regulation of NK cell recruitment.


Asunto(s)
Antígenos CD/metabolismo , Movimiento Celular , Células Asesinas Naturales/metabolismo , Proteínas de la Membrana/metabolismo , Western Blotting , Adhesión Celular , Polaridad Celular , Quimiocina CCL5/metabolismo , Quimiocina CCL5/farmacología , Quimiotaxis/efectos de los fármacos , Proteínas del Citoesqueleto/metabolismo , Citometría de Flujo , Humanos , Células Asesinas Naturales/citología , Proteínas de Microfilamentos/metabolismo , Fosforilación , Glicoproteínas de Membrana Plaquetaria/metabolismo , Unión Proteica , Proteína Quinasa C/metabolismo , Tetraspanina 28 , Tetraspanina 30 , Quinasas Asociadas a rho/metabolismo
8.
Biochem Biophys Res Commun ; 399(4): 560-4, 2010 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-20678470

RESUMEN

Focal adhesions (FAs) connect the cellular actin cytoskeleton via integrin with the extracellular matrix. They comprise of many structural and signaling proteins which are highly dynamic, well regulated, and responsible for the sensing of physical properties from the environment. Vinculin is a protein that incorporates all these functions. Here, we investigated the phosphorylation of Y1065 in the activation/regulation of vinculin. We used different vinculin mutants mimicking either a permanently activated or inhibited phosphorylation site at position 1065. Using these mutants, we determined their influence on the exchange dynamics and cell forces using fluorescence recovery after photobleaching and traction microscopy. The results indicate that phosphorylation at Y1065 significantly increases the amount of freely exchanging vinculin within FAs whereas inhibition of this phosphorylation site leads to an uncontrolled exchange of vinculin and reduced adhesive cell forces. In conclusion, we show that phosphorylation on position Y1065 is essential for accurate incorporation of vinculin into FAs and mechanical behavior of cells.


Asunto(s)
Adhesiones Focales/metabolismo , Tirosina/metabolismo , Vinculina/metabolismo , Animales , Adhesiones Focales/genética , Ratones , Ratones Noqueados , Mutación , Fosforilación , Tirosina/genética , Vinculina/genética
9.
Exp Cell Res ; 315(7): 1212-24, 2009 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-19100734

RESUMEN

Cell adhesion is an essential prerequisite for cell function and movement. It depends strongly on focal adhesion complexes connecting the extracellular matrix to the actin cytoskeleton. Especially in moving cells focal adhesions are highly dynamic and believed to be formed closely behind the leading edge. Filopodia were thought to act mainly as guiding cues using their tip complexes for elongation. Here we show for keratinocytes a strong dependence of lamellipodial adhesion sites on filopodia. Upon stable contact of the VASP-containing tip spot to the substrate, a filopodial focal complex (filopodial FX) is formed right behind along the filopodia axis. These filopodial FXs are fully assembled, yet small adhesions containing all adhesion markers tested. Filopodial FXs when reached by the lamellipodium are just increased in size resulting in classical focal adhesions. At the same time most filopodia regain their elongation ability. Blocking filopodia inhibits development of new focal adhesions in the lamellipodium, while focal adhesion maturation in terms of vinculin exchange dynamics remains active. Our data therefore argue for a strong spatial and temporal dependence of focal adhesions on filopodial focal complexes in keratinocytes with filopodia not permanently initiated via new clustering of actin filaments to induce elongation.


Asunto(s)
Adhesión Celular/fisiología , Movimiento Celular/fisiología , Queratinocitos/fisiología , Seudópodos/metabolismo , Moléculas de Adhesión Celular/metabolismo , Células Cultivadas , Proteínas del Citoesqueleto/genética , Proteínas del Citoesqueleto/metabolismo , Recuperación de Fluorescencia tras Fotoblanqueo , Adhesiones Focales/metabolismo , Glicoproteínas/genética , Glicoproteínas/metabolismo , Humanos , Queratinocitos/citología , Proteínas de Microfilamentos/metabolismo , Paxillin/genética , Paxillin/metabolismo , Fosfoproteínas/metabolismo , Seudópodos/ultraestructura , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Talina/genética , Talina/metabolismo , Vinculina/genética , Vinculina/metabolismo , Zixina
10.
Cell Motil Cytoskeleton ; 66(6): 350-64, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19422016

RESUMEN

The coordinated formation and release of focal adhesions is necessary for cell attachment and migration. According to current models, these processes are caused by temporal variations in protein composition. Protein incorporation into focal adhesions is believed to be controlled by phosphorylation. Here, we tested the exchange dynamics of GFP-vinculin as marker protein of focal adhesions using the method of Fluorescence Recovery After Photobleaching. The relevance of the phosphorylation state of the protein, the age of focal adhesions and the acting force were investigated. For stable focal adhesions of stationary keratinocytes, we determined an exchangeable vinculin fraction of 52% and a recovery halftime of 57 s. Nascent focal adhesions of moving cells contained a fraction of exchanging vinculin of 70% with a recovery halftime of 36 s. Upon maturation, mean saturation values and recovery halftimes decreased to levels of 49% and 42 s, respectively. Additionally, the fraction of stably incorporated vinculin increased with cell forces and decreased with vinculin phosphorylation within these sites. Experiments on a nonphosphorylatable vinculin mutant construct at phosphorylation site tyr1065 confirmed the direct interplay between phosphorylation and exchange dynamics of adhesion proteins during adhesion site maturation.


Asunto(s)
Adhesiones Focales/metabolismo , Queratinocitos/metabolismo , Vinculina/metabolismo , Adhesión Celular/fisiología , Movimiento Celular/fisiología , Células Cultivadas , Recuperación de Fluorescencia tras Fotoblanqueo , Humanos , Queratinocitos/citología , Fosforilación/fisiología , Vinculina/genética
11.
Neurobiol Aging ; 76: 24-34, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30640040

RESUMEN

We have developed a cell-based phenotypic automated high-content screening approach for N2a cells expressing the pro-aggregant repeat domain of tau protein (tauRDΔK), which allows analysis of a chemogenomic library of 1649 compounds for their effect on the inhibition or stimulation of intracellular tau aggregation. We identified several inhibitors and stimulators of aggregation and achieved a screening reproducibility >85% for all data. We identified 18 potential inhibitors (= 1.1% of the library) and 10 stimulators (= 0.6% of the library) of tau aggregation in this cell model of tau pathology. The results provide insights into the regulation of cellular tau aggregation and the pathways involved in this process (e.g., involving signaling via p38 mitogen-activated protein kinase, histone deacetylases, vascular endothelial growth factor, rho/ROCK). For example, inhibitors of protein kinases (e.g., p38) can reduce tau aggregation, whereas inhibitors of deacetylases (histone deacetylases) can enhance aggregation. These observations are compatible with reports that phosphorylated or acetylated tau promotes pathology.


Asunto(s)
Evaluación Preclínica de Medicamentos/métodos , Inhibidores Enzimáticos/farmacología , Agregación Patológica de Proteínas/metabolismo , Tauopatías/tratamiento farmacológico , Tauopatías/metabolismo , Proteínas tau/metabolismo , Línea Celular , Inhibidores de Histona Desacetilasas , Histona Desacetilasas/farmacología , Humanos , Modelos Biológicos , Agregación Patológica de Proteínas/genética , Transducción de Señal/genética , Transducción de Señal/fisiología , Tauopatías/genética , Proteínas Quinasas p38 Activadas por Mitógenos/antagonistas & inhibidores
12.
J Orthop Res ; 36(1): 272-281, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-28574610

RESUMEN

Previous studies suggested that degradation of contractile tissue requires cleavage of the costamere, a structural protein complex that holds sarcomeres in place. This study examined if costamere turnover is affected by a rotator cuff tear in a previously established ovine model. We found the activity of focal adhesion kinase (FAK), a main regulator of costamere turnover, was unchanged at 2 weeks but decreased by 27% 16 weeks after surgical release of the infraspinatus tendon. This was accompanied by cleavage of the costamere protein talin into a 190 kDa fragment while full length talin remained unchanged. At 2 weeks after tendon release, muscle volume decreased by 17 cm3 from an initial 185 cm3 , the fatty tissue volume was halved, and the contractile tissue volume remained unchanged. After 16 weeks, the muscle volume decreased by 36 cm3 , contractile tissue was quantitatively lost, and the fat content increased by 184%. Nandrolone administration mitigated the loss of contractile tissue by 26% and prevented fat accumulation, alterations in FAK activity, and talin cleavage. Taken together, these findings imply that muscle remodeling after tendon release occurs in two stages. The early decrease of muscle volume is associated with reduction of fat; while, the second stage is characterized by substantial loss of contractile tissue accompanied by massive fat accumulation. Regulation of costamere turnover is associated with the loss of contractile tissue and seems to be impacted by nandrolone treatment. Clinically, the costamere may represent a potential intervention target to mitigate muscle loss after a rotator cuff tear. © 2017 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 36:272-281, 2018.


Asunto(s)
Costameras/metabolismo , Proteína-Tirosina Quinasas de Adhesión Focal/metabolismo , Lesiones del Manguito de los Rotadores/metabolismo , Manguito de los Rotadores/metabolismo , Tendones/cirugía , Tejido Adiposo/metabolismo , Animales , Calcio/metabolismo , Femenino , Nandrolona/farmacología , Ovinos , Articulación del Hombro
13.
J Vis Exp ; (120)2017 02 10.
Artículo en Inglés | MEDLINE | ID: mdl-28287587

RESUMEN

The nervous system has the remarkable ability to adapt and respond to various stimuli. This neural adjustment is largely achieved through plasticity at the synaptic level. The Active Zone (AZ) is the region at the presynaptic membrane that mediates neurotransmitter release and is composed of a dense collection of scaffold proteins. AZs of Drosophila melanogaster (Drosophila) photoreceptors undergo molecular remodeling after prolonged exposure to natural ambient light. Thus the level of neuronal activity can rearrange the molecular composition of the AZ and contribute to the regulation of the functional output. Starting from the light exposure set-up preparation to the immunohistochemistry, this protocol details how to quantify the number, the spatial distribution, and the delocalization level of synaptic molecules at AZs in Drosophila photoreceptors. Using image analysis software, clusters of the GFP-fused AZ component Bruchpilot were identified for each R8 photoreceptor (R8) axon terminal. Detected Bruchpilot spots were automatically assigned to individual R8 axons. To calculate the distribution of spot frequency along the axon, we implemented a customized software plugin. Each axon's start-point and end-point were manually defined and the position of each Bruchpilot spot was projected onto the connecting line between start and end-point. Besides the number of Bruchpilot clusters, we also quantified the delocalization level of Bruchpilot-GFP within the clusters. These measurements reflect in detail the spatially resolved synaptic dynamics in a single neuron under different environmental conditions to stimuli.


Asunto(s)
Luz , Células Fotorreceptoras de Invertebrados/efectos de la radiación , Transmisión Sináptica/fisiología , Animales , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Proteínas Fluorescentes Verdes/metabolismo , Sustancias Luminiscentes/metabolismo , Células Fotorreceptoras de Invertebrados/metabolismo , Terminales Presinápticos , Unión Proteica , Transporte de Proteínas , Sinapsis/metabolismo
14.
J Steroid Biochem Mol Biol ; 165(Pt B): 382-395, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27523963

RESUMEN

Reversal of fatty infiltration of pennate rotator cuff muscle after tendon release is hitherto impossible. The administration of nandrolone starting at the time of tendon release prevents the increase in fat content, but does not revert established fatty infiltration. We hypothesised that tendon release and myotendinous retraction cause alterations in lipid related gene expression leading to fatty muscle infiltration, which can be suppressed by nandrolone through its genomic actions if applied immediately after tendon release. The effects of infraspinatus tendon release and subsequent tendon repair at 16 weeks were studied in six Swiss Alpine sheep. In the interventional groups, 150mg nandrolone was administered weekly after tendon release until sacrifice (N22W, n=6) or starting at the time of repair (N6W, n=6). Infraspinatus volume, composition, expressed transcripts, lipids, and selected proteins were analyzed at baseline, 16 and 22 weeks. Tendon release reduced infraspinatus volume by 22% and increased fat content from 11% to 38%. These changes were not affected by repair. Fatty infiltration was associated with up-regulation of 227 lipid species, and increased levels of the adipocyte differentiation marker PPARG2 (peroxisome proliferator-activated receptor gamma 2). Nandrolone abrogated lipid accumulation, halved the loss in fiber area percentage, and up-regulated androgen receptor levels and transcript expression in the N22W but not the N6W group. The results document that nandrolone mitigates muscle-to-fat transformation after tendon release via a general down-regulation of lipid accumulation concomitantly with up-regulated expression of its nuclear receptor and downstream transcripts in skeletal muscle. Reduced responsiveness of retracted muscle to nandrolone as observed in the N6W group is reflected by a down-regulated transcript response.


Asunto(s)
Músculo Esquelético/efectos de los fármacos , Nandrolona/farmacología , Manguito de los Rotadores/patología , Traumatismos de los Tendones/patología , Tendones/patología , Adipocitos/citología , Anabolizantes/farmacología , Animales , Atrofia/patología , Regulación hacia Abajo , Femenino , Regulación de la Expresión Génica , Genómica , Metabolismo de los Lípidos , Músculo Esquelético/metabolismo , Músculos/metabolismo , Receptores Androgénicos/metabolismo , Ovinos , Oveja Doméstica , Esteroides/química , Esteroides/uso terapéutico , Tenotomía , Transcriptoma
15.
Neuron ; 86(3): 711-25, 2015 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-25892303

RESUMEN

Neural activity contributes to the regulation of the properties of synapses in sensory systems, allowing for adjustment to a changing environment. Little is known about how synaptic molecular components are regulated to achieve activity-dependent plasticity at central synapses. Here, we found that after prolonged exposure to natural ambient light the presynaptic active zone in Drosophila photoreceptors undergoes reversible remodeling, including loss of Bruchpilot, DLiprin-α, and DRBP, but not of DSyd-1 or Cacophony. The level of depolarization of the postsynaptic neurons is critical for the light-induced changes in active zone composition in the photoreceptors, indicating the existence of a feedback signal. In search of this signal, we have identified a crucial role of microtubule meshwork organization downstream of the divergent canonical Wnt pathway, potentially via Kinesin-3 Imac. These data reveal that active zone composition can be regulated in vivo and identify the underlying molecular machinery.


Asunto(s)
Retroalimentación Fisiológica/fisiología , Células Fotorreceptoras de Invertebrados/citología , Terminales Presinápticos/fisiología , Animales , Drosophila , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Péptidos y Proteínas de Señalización Intracelular , Canales Iónicos , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Ratones Transgénicos , Microscopía Electrónica de Transmisión , Modelos Biológicos , Fenotipo , Fosfoproteínas/metabolismo , Estimulación Luminosa , Células Fotorreceptoras de Invertebrados/clasificación , Células Fotorreceptoras de Invertebrados/metabolismo , Terminales Presinápticos/ultraestructura , Transducción de Señal/genética , Sinapsis/fisiología , Sinapsis/ultraestructura , Canal Catiónico TRPA1 , Canales Catiónicos TRPC/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
16.
Cell Adh Migr ; 4(2): 215-25, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20179423

RESUMEN

Migration of cells is one of the most essential prerequisites to form higher organisms and depends on a strongly coordinated sequence of processes. Early migratory events include substrate sensing, adhesion formation, actin bundle assembly and force generation. While substrate sensing was ascribed to filopodia, all other processes were believed to depend mainly on lamellipodia of migrating cells. In this work we show for motile keratinocytes that all processes from substrate sensing to force generation strongly depend on filopodial focal complexes as well as on filopodial actin bundles. In a coordinated step by step process, filopodial focal complexes have to be tightly adhered to the substrate and to filopodial actin bundles to enlarge upon lamellipodial contact forming classical focal adhesions. Lamellipodial actin filaments attached to those focal adhesions originate from filopodia. Upon cell progression, the incorporation of filopodial actin bundles into the lamellipodium goes along with a complete change in actin cross-linker composition from filopodial fascin to lamellipodial alpha-actinin. alpha-Actinin in turn is replaced by myosin II and becomes incorporated directly behind the leading edge. Myosin II activity makes this class of actin bundles with their attached FAs the major source of force generation and transmission at the cell front. Furthermore, connection of FAs to force generating actin bundles leads to their stabilization and further enlargement. Consequently, adhesion sites formed independently of filopodia are not connected to detectable actin bundles, transmit weak forces to the substrate and disassemble within a few minutes without having been increased in size.


Asunto(s)
Actinas/metabolismo , Movimiento Celular/fisiología , Seudópodos/metabolismo , Adhesión Celular/genética , Adhesión Celular/fisiología , Movimiento Celular/genética , Células Cultivadas , Técnica del Anticuerpo Fluorescente , Humanos , Microscopía Fluorescente , Modelos Biológicos
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