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1.
Brain ; 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38964748

RESUMEN

Early pathological upregulation of adenosine A2A receptors (A2ARs), one of the caffeine targets, by neurons is thought to be involved in the development of synaptic and memory deficits in Alzheimer's disease (AD) but mechanisms remain ill-defined. To tackle this question, we promoted a neuronal upregulation of A2AR in the hippocampus of APP/PS1 mice developing AD-like amyloidogenesis. Our findings revealed that the early upregulation of A2AR in the presence of an ongoing amyloid pathology exacerbates memory impairments of APP/PS1 mice. These behavioural changes were not linked to major change in the development of amyloid pathology but rather associated with increased phosphorylated tau at neuritic plaques. Moreover, proteomic and transcriptomic analyses coupled with quantitative immunofluorescence studies indicated that neuronal upregulation of the receptor promoted both neuronal and non-neuronal autonomous alterations, i.e. enhanced neuroinflammatory response but also loss of excitatory synapses and impaired neuronal mitochondrial function, presumably accounting for the detrimental effect on memory. Overall, our results provide compelling evidence that neuronal A2AR dysfunction, as seen in the brain of patients, contributes to amyloid-related pathogenesis and underscores the potential of A2AR as a relevant therapeutic target for mitigating cognitive impairments in this neurodegenerative disorder.

2.
Int J Mol Sci ; 25(2)2024 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-38256109

RESUMEN

The available antipsychotics for schizophrenia (SZ) only reduce positive symptoms and do not significantly modify SZ neurobiology. This has raised the question of the robustness and translational value of methods employed during drug development. Electroencephalography (EEG)-based measures like evoked and spontaneous gamma oscillations are considered robust translational biomarkers as they can be recorded in both patients and animal models to probe a key mechanism underlying all SZ symptoms: the excitation/inhibition imbalance mediated by N-methyl-D-aspartate receptor (NMDAr) hypofunction. Understanding the effects of commercialized atypical antipsychotics on such measures could therefore contribute to developing better therapies for SZ. Yet, the effects of such drugs on these EEG readouts are unknown. Here, we studied the effect of the atypical antipsychotic aripiprazole on the gamma-band auditory steady-state response (ASSR), spontaneous gamma oscillations and behavioral features in a SZ rat model induced by the NMDAr antagonist MK-801. Interestingly, we found that aripiprazole could not normalize MK-801-induced abnormalities in ASSR, spontaneous gamma oscillations or social interaction while it still improved MK-801-induced hyperactivity. Suggesting that aripiprazole is unable to normalize electrophysiological features underlying SZ symptoms, our results might explain aripiprazole's inefficacy towards the social interaction deficit in our model but also its limited efficacy against social symptoms in patients.


Asunto(s)
Antipsicóticos , Esquizofrenia , Humanos , Animales , Ratas , Aripiprazol/farmacología , Esquizofrenia/tratamiento farmacológico , Maleato de Dizocilpina/farmacología , Antipsicóticos/farmacología , Electroencefalografía , Receptores de N-Metil-D-Aspartato
3.
Cell Mol Life Sci ; 79(8): 431, 2022 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-35852606

RESUMEN

Amyotrophic lateral sclerosis (ALS) is a fatal motoneuron (MN) disease characterized by protein misfolding and aggregation leading to cellular degeneration. So far neither biomarker, nor effective treatment has been found. ATP signaling and P2X4 receptors (P2X4) are upregulated in various neurodegenerative diseases. Here we show that several ALS-related misfolded proteins including mutants of SOD1 or TDP-43 lead to a significant increase in surface P2X4 receptor density and function in vitro. In addition, we demonstrate in the spinal the cord of SOD1-G93A (SOD1) mice that misfolded SOD1-G93A proteins directly interact with endocytic adaptor protein-2 (AP2); thus, acting as negative competitors for the interaction between AP2 and P2X4, impairing constitutive P2X4 endocytosis. The higher P2X4 surface density was particularly observed in peripheral macrophages of SOD1 mice before the onset and during the progression of ALS symptoms positioning P2X4 as a potential early biomarker for ALS. P2X4 expression was also upregulated in spinal microglia of SOD1 mice during ALS and affect microglial inflammatory responses. Importantly, we report using double transgenic SOD1 mice expressing internalization-defective P2X4mCherryIN knock-in gene or invalidated for the P2X4 gene that P2X4 is instrumental for motor symptoms, ALS progression and survival. This study highlights the role of P2X4 in the pathophysiology of ALS and thus its potential for the development of biomarkers and treatments. We also decipher the molecular mechanism by which misfolded proteins related to ALS impact P2X4 trafficking at early pathological stage in cells expressing-P2X4.


Asunto(s)
Esclerosis Amiotrófica Lateral , Enfermedad de la Neurona Motora , Receptores Purinérgicos P2X4 , Superóxido Dismutasa-1 , Esclerosis Amiotrófica Lateral/genética , Esclerosis Amiotrófica Lateral/metabolismo , Esclerosis Amiotrófica Lateral/patología , Animales , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Ratones , Ratones Transgénicos , Enfermedad de la Neurona Motora/genética , Enfermedad de la Neurona Motora/metabolismo , Enfermedad de la Neurona Motora/patología , Neuronas Motoras/metabolismo , Neuronas Motoras/patología , Receptores Purinérgicos P2X4/genética , Receptores Purinérgicos P2X4/metabolismo , Médula Espinal/metabolismo , Superóxido Dismutasa-1/genética , Superóxido Dismutasa-1/metabolismo
4.
Brain ; 144(4): 1167-1182, 2021 05 07.
Artículo en Inglés | MEDLINE | ID: mdl-33842937

RESUMEN

Deposits of different abnormal forms of tau in neurons and astrocytes represent key anatomo-pathological features of tauopathies. Although tau protein is highly enriched in neurons and poorly expressed by astrocytes, the origin of astrocytic tau is still elusive. Here, we used innovative gene transfer tools to model tauopathies in adult mouse brains and to investigate the origin of astrocytic tau. We showed in our adeno-associated virus (AAV)-based models and in Thy-Tau22 transgenic mice that astrocytic tau pathology can emerge secondarily to neuronal pathology. By designing an in vivo reporter system, we further demonstrated bidirectional exchanges of tau species between neurons and astrocytes. We then determined the consequences of tau accumulation in astrocytes on their survival in models displaying various status of tau aggregation. Using stereological counting of astrocytes, we report that, as for neurons, soluble tau species are highly toxic to some subpopulations of astrocytes in the hippocampus, whereas the accumulation of tau aggregates does not affect their survival. Thus, astrocytes are not mere bystanders of neuronal pathology. Our results strongly suggest that tau pathology in astrocytes may significantly contribute to clinical symptoms.


Asunto(s)
Astrocitos/patología , Hipocampo/patología , Tauopatías/patología , Proteínas tau/toxicidad , Animales , Humanos , Masculino , Ratones , Neuronas/patología , Agregado de Proteínas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/toxicidad , Tauopatías/metabolismo , Proteínas tau/genética , Proteínas tau/metabolismo
5.
Brain ; 144(10): 3142-3158, 2021 11 29.
Artículo en Inglés | MEDLINE | ID: mdl-34086871

RESUMEN

Traumatic brain injury (TBI) leads to major brain anatomopathological damages underlined by neuroinflammation, oxidative stress and progressive neurodegeneration, ultimately leading to motor and cognitive deterioration. The multiple pathological events resulting from TBI can be addressed not by a single therapeutic approach, but rather by a synergistic biotherapy capable of activating a complementary set of signalling pathways and providing synergistic neuroprotective, anti-inflammatory, antioxidative, and neurorestorative activities. Human platelet lysate might fulfil these requirements as it is composed of a plethora of biomolecules readily accessible as a TBI biotherapy. In the present study, we tested the therapeutic potential of human platelet lysate using in vitro and in vivo models of TBI. We first prepared and characterized platelet lysate from clinical-grade human platelet concentrates. Platelets were pelletized, lysed by three freeze-thaw cycles, and centrifuged. The supernatant was purified by 56°C 30 min heat treatment and spun to obtain the heat-treated platelet pellet lysate that was characterized by ELISA and proteomic analyses. Two mouse models were used to investigate platelet lysate neuroprotective potential. The injury was induced by an in-house manual controlled scratching of the animals' cortex or by controlled cortical impact injury. The platelet lysate treatment was performed by topical application of 60 µl in the lesioned area, followed by daily 60 µl intranasal administration from Day 1 to 6 post-injury. Platelet lysate proteomics identified over 1000 proteins including growth factors, neurotrophins, and antioxidants. ELISA detected several neurotrophic and angiogenic factors at ∼1-50 ng/ml levels. We demonstrate, using two mouse models of TBI, that topical application and intranasal platelet lysate consistently improved mouse motor function in the beam and rotarod tests, mitigated cortical neuroinflammation, and oxidative stress in the injury area, as revealed by downregulation of pro-inflammatory genes and the reduction in reactive oxygen species levels. Moreover, platelet lysate treatment reduced the loss of cortical synaptic proteins. Unbiased proteomic analyses revealed that heat-treated platelet pellet lysate reversed several pathways promoted by both controlled cortical impact and cortical brain scratch and related to transport, postsynaptic density, mitochondria or lipid metabolism. The present data strongly support, for the first time, that human platelet lysate is a reliable and effective therapeutic source of neurorestorative factors. Therefore, brain administration of platelet lysate is a therapeutical strategy that deserves serious and urgent consideration for universal brain trauma treatment.


Asunto(s)
Terapia Biológica/métodos , Plaquetas/metabolismo , Lesiones Traumáticas del Encéfalo/metabolismo , Lesiones Traumáticas del Encéfalo/terapia , Administración Intranasal , Animales , Lesiones Traumáticas del Encéfalo/patología , Línea Celular Tumoral , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL
6.
Sensors (Basel) ; 21(17)2021 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-34502820

RESUMEN

Internet of Things (IoT) applications are becoming more integrated into our society and daily lives, although many of them can expose the user to threats against their privacy. Therefore, we find that it is crucial to address the privacy requirements of most of such applications and develop solutions that implement, as far as possible, privacy by design in order to mitigate relevant threats. While in the literature we may find innovative proposals to enhance the privacy of IoT applications, many of those only focus on the edge layer. On the other hand, privacy by design approaches are required throughout the whole system (e.g., at the cloud layer), in order to guarantee robust solutions to privacy in IoT. With this in mind, we propose an architecture that leverages the properties of blockchain, integrated with other technologies, to address security and privacy in the context of IoT applications. The main focus of our proposal is to enhance the privacy of the users and their data, using the anonymisation properties of blockchain to implement user-controlled privacy. We consider an IoT application with mobility for smart vehicles as our usage case, which allows us to implement and experimentally evaluate the proposed architecture and mechanisms as a proof of concept. In this application, data related to the user's identity and location needs to be shared with security and privacy. Our proposal was implemented and experimentally validated in light of fundamental privacy and security requirements, as well as its performance. We found it to be a viable approach to security and privacy in IoT environments.

7.
Inflammopharmacology ; 29(3): 735-752, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33881683

RESUMEN

This study aims to investigate the activity of n-hexane, ethyl acetate and butanol fractions obtained from Arrabidaea chica Verlot against MIA-induced osteoarthritis (OA). The antinociceptive potentials of each fraction were evaluated through a cyclooxygenase (COX) 1 and 2 inhibition test and an in vivo OA-model. In addition, toxicity assessments in the liver, spleen and kidney, as well as radiographic and histopathological knee analyses, were performed. The chemical composition of the n-hexane fraction was elucidated, and a molecular docking protocol was carried out to identify which compounds are associated with the detected bioactivity. The n-hexane A. chica fraction preferentially inhibits COX-2, with 90% inhibition observed at 10 µg/mL. The fractions also produced significant improvements in OA incapacity, motor activity and hyperalgesia parameters and in radiological knee conditions. However, concerning the histopathological evaluations, these improvements were only significant in the hexane and ethyl acetate fraction treatments, which resulted in better average scores, suggesting that these fractions slow OA-promoted joint injury progression. Histopathological organ analyses indicate that the fractions are not toxic to animals. Twenty compounds were identified in the n-hexane fraction, comprising fatty acids, terpenes and phytosterols. In silico analyses indicate the presence of favourable interactions between some of the identified compounds and the COX-2 enzyme, mainly concerning alpha-tocopherol (Vitamin E), squalene and beta-sitosterol. The findings indicate that A. chica fractions display analgesic, anti-inflammatory properties, are non-toxic and are able to slow OA progression, and may, therefore, be prioritized as natural products in OA human clinical trials.


Asunto(s)
Analgésicos/uso terapéutico , Antiinflamatorios/uso terapéutico , Osteoartritis/tratamiento farmacológico , Extractos Vegetales/uso terapéutico , Plantas Medicinales , Analgésicos/aislamiento & purificación , Analgésicos/farmacología , Animales , Antiinflamatorios/aislamiento & purificación , Antiinflamatorios/farmacología , Masculino , Simulación del Acoplamiento Molecular/métodos , Actividad Motora/efectos de los fármacos , Actividad Motora/fisiología , Osteoartritis/metabolismo , Osteoartritis/patología , Extractos Vegetales/aislamiento & purificación , Extractos Vegetales/farmacología , Estructura Secundaria de Proteína , Ratas , Ratas Wistar
8.
Brain ; 142(11): 3636-3654, 2019 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-31599329

RESUMEN

Accumulating data support the role of tau pathology in cognitive decline in ageing and Alzheimer's disease, but underlying mechanisms remain ill-defined. Interestingly, ageing and Alzheimer's disease have been associated with an abnormal upregulation of adenosine A2A receptor (A2AR), a fine tuner of synaptic plasticity. However, the link between A2AR signalling and tau pathology has remained largely unexplored. In the present study, we report for the first time a significant upregulation of A2AR in patients suffering from frontotemporal lobar degeneration with the MAPT P301L mutation. To model these alterations, we induced neuronal A2AR upregulation in a tauopathy mouse model (THY-Tau22) using a new conditional strain allowing forebrain overexpression of the receptor. We found that neuronal A2AR upregulation increases tau hyperphosphorylation, potentiating the onset of tau-induced memory deficits. This detrimental effect was linked to a singular microglial signature as revealed by RNA sequencing analysis. In particular, we found that A2AR overexpression in THY-Tau22 mice led to the hippocampal upregulation of C1q complement protein-also observed in patients with frontotemporal lobar degeneration-and correlated with the loss of glutamatergic synapses, likely underlying the observed memory deficits. These data reveal a key impact of overactive neuronal A2AR in the onset of synaptic loss in tauopathies, paving the way for new therapeutic approaches.


Asunto(s)
Complemento C1q/metabolismo , Neuronas/metabolismo , Receptor de Adenosina A2A/genética , Receptor de Adenosina A2A/metabolismo , Sinapsis/patología , Tauopatías/genética , Tauopatías/patología , Animales , Autopsia , Degeneración Lobar Frontotemporal/genética , Degeneración Lobar Frontotemporal/metabolismo , Hipocampo/metabolismo , Hipocampo/patología , Humanos , Trastornos de la Memoria/etiología , Trastornos de la Memoria/psicología , Ratones , Ratones Transgénicos , Mutación , Aprendizaje Espacial , Tauopatías/psicología , Proteínas tau/genética
9.
Glia ; 67(12): 2329-2342, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31328322

RESUMEN

Adenosine A2A receptors (A2A R) are modulators of various physiological processes essential for brain homeostasis and fine synaptic tuning. In certain neurodegenerative conditions, notably Alzheimer's disease (AD), A2A Rs are pathologically upregulated in neurons but also in astrocytes. In that context, the use of A2A Rs inhibitors, normalizing impaired receptor function, is seen as a potential therapeutic strategy. However, the impact of A2A R alterations, particularly in astrocytes, is not fully understood. Here, we investigated the effect of A2A R overexpression on transcriptional deregulation in primary astrocytic cultures. By performing whole transcriptome analysis, we found that A2A R overexpression promotes robust transcriptional changes, mostly affecting immune response, angiogenesis, and cell activation-related genes. Importantly, we observed that treatment with SCH58261, a selective A2A R antagonist, restored the expression levels of several inflammatory and astrocytic activation-related genes, such as Interleukin-1beta and vimentin. This supports the notion that A2A R blockade could restore some astrocytic dysfunctions associated with abnormal A2A R expression, further arguing for a potential beneficial impact of receptor antagonists in A2A R-induced transcriptional deregulation, inflammation, and astrogliosis. Overall, our findings provide novel insights into the putative impact of A2A R overexpression on transcriptional deregulation in astrocytes, thereby opening novel avenues for the use of A2A R antagonists as potential therapeutic strategy in neurodegenerative diseases.


Asunto(s)
Antagonistas del Receptor de Adenosina A2/farmacología , Astrocitos/fisiología , Receptor de Adenosina A2A/genética , Receptor de Adenosina A2A/metabolismo , Transcripción Genética/fisiología , Animales , Animales Recién Nacidos , Astrocitos/efectos de los fármacos , Células Cultivadas , Redes Reguladoras de Genes/efectos de los fármacos , Redes Reguladoras de Genes/fisiología , Ratones , Transcripción Genética/efectos de los fármacos
10.
Neurobiol Dis ; 125: 14-22, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30665005

RESUMEN

Accumulation of hyper-phosphorylated and aggregated Tau proteins is a neuropathological hallmark of Alzheimer's Disease (AD) and Tauopathies. AD patient brains also exhibit insulin resistance. Whereas, under normal physiological conditions insulin signaling in the brain mediates plasticity and memory formation, it can also regulate peripheral energy homeostasis. Thus, in AD, brain insulin resistance affects both cognitive and metabolic changes described in these patients. While a role of Aß oligomers and APOE4 towards the development of brain insulin resistance emerged, contribution of Tau pathology has been largely overlooked. Our recent data demonstrated that one of the physiological function of Tau is to sustain brain insulin signaling. We postulated that under pathological conditions, hyper-phosphorylated/aggregated Tau is likely to lose this function and to favor the development of brain insulin resistance. This hypothesis was substantiated by observations from patient brains with pure Tauopathies. To address the potential link between Tau pathology and brain insulin resistance, we have evaluated the brain response to insulin in a transgenic mouse model of AD-like Tau pathology (THY-Tau22). Using electrophysiological and biochemical evaluations, we surprisingly observed that, at a time when Tau pathology and cognitive deficits are overt and obvious, the hippocampus of THY-Tau22 mice exhibits enhanced response to insulin. In addition, we demonstrated that the ability of i.c.v. insulin to promote body weight loss is enhanced in THY-Tau22 mice. In line with this, THY-Tau22 mice exhibited a lower body weight gain, hypoleptinemia and hypoinsulinemia and finally a metabolic resistance to high-fat diet. The present data highlight that the brain of transgenic Tau mice exhibit enhanced brain response to insulin. Whether these observations are ascribed to the development of Tau pathology, and therefore relevant to human Tauopathies, or unexpectedly results from the Tau transgene overexpression is debatable and discussed.


Asunto(s)
Encéfalo/metabolismo , Insulina/metabolismo , Tauopatías/metabolismo , Proteínas tau/metabolismo , Animales , Resistencia a la Insulina/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Proteínas tau/genética
11.
Sensors (Basel) ; 19(5)2019 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-30823677

RESUMEN

This paper introduces a strategy for the path planning problem for platforms with limited sensor and processing capabilities. The proposed algorithm does not require any prior information but assumes that a mapping algorithm is used. If enough information is available, a global path planner finds sub-optimal collision-free paths within the known map. For the real time obstacle avoidance task, a simple and cost-efficient local planner is used, making the algorithm a hybrid global and local planning solution. The strategy was tested in a real, cluttered environment experiment using the Pioneer P3-DX and the Xbox 360 kinect sensor, to validate and evaluate the algorithm efficiency.

12.
Brain ; 140(1): 184-200, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27818384

RESUMEN

Alzheimer's disease is characterized by the combined presence of amyloid plaques and tau pathology, the latter being correlated with the progression of clinical symptoms. Neuroinflammatory changes are thought to be major contributors to Alzheimer's disease pathophysiology, even if their precise role still remains largely debated. Notably, to what extent immune responses contribute to cognitive impairments promoted by tau pathology remains poorly understood. To address this question, we took advantage of the THY-Tau22 mouse model that progressively develops hippocampal tau pathology paralleling cognitive deficits and reappraised the interrelationship between tau pathology and brain immune responses. In addition to conventional astroglial and microglial responses, we identified a CD8-positive T cell infiltration in the hippocampus of tau transgenic mice associated with an early chemokine response, notably involving CCL3. Interestingly, CD8-positive lymphocyte infiltration was also observed in the cortex of patients exhibiting frontemporal dementia with P301L tau mutation. To gain insights into the functional involvement of T cell infiltration in the pathophysiological development of tauopathy in THY-Tau22 mice, we chronically depleted T cells using anti-CD3 antibody. Such anti-CD3 treatment prevented hippocampal T cell infiltration in tau transgenic animals and reverted spatial memory deficits, in absence of tau pathology modulation. Altogether, these data support an instrumental role of hippocampal T cell infiltration in tau-driven pathophysiology and cognitive impairments in Alzheimer's disease and other tauopathies.


Asunto(s)
Anticuerpos/uso terapéutico , Complejo CD3/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Corteza Cerebral/inmunología , Quimiocinas/inmunología , Disfunción Cognitiva/inmunología , Hipocampo/inmunología , Inflamación/inmunología , Tauopatías/inmunología , Anciano , Animales , Disfunción Cognitiva/terapia , Modelos Animales de Enfermedad , Humanos , Inflamación/terapia , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Persona de Mediana Edad , Tauopatías/terapia
13.
Proc Natl Acad Sci U S A ; 110(41): 16456-61, 2013 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-24065829

RESUMEN

Animal cells actively generate contractile stress in the actin cortex, a thin actin network beneath the cell membrane, to facilitate shape changes during processes like cytokinesis and motility. On the microscopic scale, this stress is generated by myosin molecular motors, which bind to actin cytoskeletal filaments and use chemical energy to exert pulling forces. To decipher the physical basis for the regulation of cell shape changes, here, we use a cell-like system with a cortex anchored to the outside or inside of a liposome membrane. This system enables us to dissect the interplay between motor pulling forces, cortex-membrane anchoring, and network connectivity. We show that cortices on the outside of liposomes either spontaneously rupture and relax built-up mechanical stress by peeling away around the liposome or actively compress and crush the liposome. The decision between peeling and crushing depends on the cortical tension determined by the amount of motors and also on the connectivity of the cortex and its attachment to the membrane. Membrane anchoring strongly affects the morphology of cortex contraction inside liposomes: cortices contract inward when weakly attached, whereas they contract toward the membrane when strongly attached. We propose a physical model based on a balance of active tension and mechanical resistance to rupture. Our findings show how membrane attachment and network connectivity are able to regulate actin cortex remodeling and membrane-shape changes for cell polarization.


Asunto(s)
Actomiosina/metabolismo , Forma de la Célula/fisiología , Citoesqueleto/metabolismo , Liposomas/química , Proteínas Motoras Moleculares/metabolismo , Animales , Microscopía Fluorescente , Conejos
14.
Proc Natl Acad Sci U S A ; 109(36): 14440-5, 2012 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-22908255

RESUMEN

Cells use their dynamic actin network to control their mechanics and motility. These networks are made of branched actin filaments generated by the Arp2/3 complex. Here we study under which conditions the microscopic organization of branched actin networks builds up a sufficient stress to trigger sustained motility. In our experimental setup, dynamic actin networks or "gels" are grown on a hard bead in a controlled minimal protein system containing actin monomers, profilin, the Arp2/3 complex and capping protein. We vary protein concentrations and follow experimentally and through simulations the shape and mechanical properties of the actin gel growing around beads. Actin gel morphology is controlled by elementary steps including "primer" contact, growth of the network, entanglement, mechanical interaction and force production. We show that varying the biochemical orchestration of these steps can lead to the loss of network cohesion and the lack of effective force production. We propose a predictive phase diagram of actin gel fate as a function of protein concentrations. This work unveils how, in growing actin networks, a tight biochemical and physical coupling smoothens initial primer-caused heterogeneities and governs force buildup and cell motility.


Asunto(s)
Actinas/metabolismo , Movimiento Celular/fisiología , Modelos Biológicos , Complejos Multiproteicos/metabolismo , Fenómenos Biomecánicos , Simulación por Computador , Cartilla de ADN/genética , Microesferas
15.
Biophys J ; 107(4): 854-62, 2014 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-25140420

RESUMEN

Actin is ubiquitous globular protein that polymerizes into filaments and forms networks that participate in the force generation of eukaryotic cells. Such forces are used for cell motility, cytokinesis, and tissue remodeling. Among those actin networks, we focus on the actin cortex, a dense branched network beneath the plasma membrane that is of particular importance for the mechanical properties of the cell. Here we reproduce the cellular cortex by activating actin filament growth on a solid surface. We unveil the existence of a sparse actin network that emanates from the surface and extends over a distance that is at least 10 times larger than the cortex itself. We call this sparse actin network the "actin cloud" and characterize its mechanical properties with optical tweezers. We show, both experimentally and theoretically, that the actin cloud is mechanically relevant and that it should be taken into account because it can sustain forces as high as several picoNewtons (pN). In particular, it is known that in plant cells, actin networks similar to the actin cloud have a role in positioning the nucleus; in large oocytes, they play a role in driving chromosome movement. Recent evidence shows that such networks even prevent granule condensation in large cells.


Asunto(s)
Citoesqueleto de Actina/química , Actinas/química , Fenómenos Biomecánicos , Materiales Biomiméticos/química , Módulo de Elasticidad , Modelos Biológicos , Dinámicas no Lineales , Pinzas Ópticas , Poliestirenos/química
16.
Nutrients ; 15(21)2023 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-37960344

RESUMEN

Early-life exposure to high-fat diets (HF) can program metabolic and cognitive alterations in adult offspring. Although the hippocampus plays a crucial role in memory and metabolic homeostasis, few studies have reported the impact of maternal HF on this structure. We assessed the effects of maternal HF during lactation on physiological, metabolic, and cognitive parameters in young adult offspring mice. To identify early-programming mechanisms in the hippocampus, we developed a multi-omics strategy in male and female offspring. Maternal HF induced a transient increased body weight at weaning, and a mild glucose intolerance only in 3-month-old male mice with no change in plasma metabolic parameters in adult male and female offspring. Behavioral alterations revealed by a Barnes maze test were observed both in 6-month-old male and female mice. The multi-omics strategy unveiled sex-specific transcriptomic and proteomic modifications in the hippocampus of adult offspring. These studies that were confirmed by regulon analysis show that, although genes whose expression was modified by maternal HF were different between sexes, the main pathways affected were similar with mitochondria and synapses as main hippocampal targets of maternal HF. The effects of maternal HF reported here may help to better characterize sex-dependent molecular pathways involved in cognitive disorders and neurodegenerative diseases.


Asunto(s)
Dieta Alta en Grasa , Efectos Tardíos de la Exposición Prenatal , Animales , Ratones , Femenino , Masculino , Humanos , Dieta Alta en Grasa/efectos adversos , Obesidad/etiología , Obesidad/metabolismo , Multiómica , Proteómica , Lactancia , Hipocampo/metabolismo , Fenómenos Fisiologicos Nutricionales Maternos/fisiología , Efectos Tardíos de la Exposición Prenatal/metabolismo
17.
Neuropharmacology ; 209: 108999, 2022 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-35181375

RESUMEN

Due to the pathophysiological complexity of Alzheimer's disease, multitarget approaches able to mitigate several pathogenic mechanisms are of interest. Previous studies have pointed to the neuroprotective potential of Doxycycline (Dox), a safe and inexpensive second-generation tetracycline. Dox has been particularly reported to slow down aggregation of misfolded proteins but also to mitigate neuroinflammatory processes. Here, we have evaluated the pre-clinical potential of Dox in the APP/PS1 mouse model of amyloidogenesis. Dox was provided to APP/PS1 mice from the age of 8 months, when animals already exhibit amyloid pathology and memory deficits. Spatial memory was then evaluated from 9 to 10 months of age. Our data demonstrated that Dox moderately improved the spatial memory of APP/PS1 mice without exerting major effect on amyloid lesions. While Dox did not alleviate overall glial reactivity, we could evidence that it rather enhanced the amyloid-dependent upregulation of several neuroinflammatory markers such as CCL3 and CCL4. Finally, Dox exerted differentially regulated the levels of synaptic proteins in the hippocampus and the cortex of APP/PS1 mice. Overall, these observations support that chronic Dox delivery does not provide major pathophysiological improvements in the APP/PS1 mouse model.


Asunto(s)
Enfermedad de Alzheimer , Precursor de Proteína beta-Amiloide , Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Modelos Animales de Enfermedad , Doxiciclina/farmacología , Doxiciclina/uso terapéutico , Hipocampo/metabolismo , Ratones , Ratones Transgénicos , Presenilina-1/genética , Presenilina-1/metabolismo
18.
Front Mol Neurosci ; 15: 841892, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35250480

RESUMEN

Alzheimer's disease (AD) is the leading cause of dementia. While impaired glucose homeostasis has been shown to increase AD risk and pathological loss of tau function, the latter has been suggested to contribute to the emergence of the glucose homeostasis alterations observed in AD patients. However, the links between tau impairments and glucose homeostasis, remain unclear. In this context, the present study aimed at investigating the metabolic phenotype of a new tau knock-in (KI) mouse model, expressing, at a physiological level, a human tau protein bearing the P301L mutation under the control of the endogenous mouse Mapt promoter. Metabolic investigations revealed that, while under chow diet tau KI mice do not exhibit significant metabolic impairments, male but not female tau KI animals under High-Fat Diet (HFD) exhibited higher insulinemia as well as glucose intolerance as compared to control littermates. Using immunofluorescence, tau protein was found colocalized with insulin in the ß cells of pancreatic islets in both mouse (WT, KI) and human pancreas. Isolated islets from tau KI and tau knock-out mice exhibited impaired glucose-stimulated insulin secretion (GSIS), an effect recapitulated in the mouse pancreatic ß-cell line (MIN6) following tau knock-down. Altogether, our data indicate that loss of tau function in tau KI mice and, particularly, dysfunction of pancreatic ß cells might promote glucose homeostasis impairments and contribute to metabolic changes observed in AD.

19.
J Clin Invest ; 132(12)2022 06 15.
Artículo en Inglés | MEDLINE | ID: mdl-35536645

RESUMEN

Caffeine is the most widely consumed psychoactive substance in the world. Strikingly, the molecular pathways engaged by its regular consumption remain unclear. We herein addressed the mechanisms associated with habitual (chronic) caffeine consumption in the mouse hippocampus using untargeted orthogonal omics techniques. Our results revealed that chronic caffeine exerts concerted pleiotropic effects in the hippocampus at the epigenomic, proteomic, and metabolomic levels. Caffeine lowered metabolism-related processes (e.g., at the level of metabolomics and gene expression) in bulk tissue, while it induced neuron-specific epigenetic changes at synaptic transmission/plasticity-related genes and increased experience-driven transcriptional activity. Altogether, these findings suggest that regular caffeine intake improves the signal-to-noise ratio during information encoding, in part through fine-tuning of metabolic genes, while boosting the salience of information processing during learning in neuronal circuits.


Asunto(s)
Cafeína , Proteómica , Animales , Cafeína/metabolismo , Cafeína/farmacología , Hipocampo/metabolismo , Aprendizaje , Ratones , Plasticidad Neuronal/fisiología
20.
J Clin Invest ; 132(22)2022 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-36377661

RESUMEN

Cisplatin is a potent chemotherapeutic drug that is widely used in the treatment of various solid cancers. However, its clinical effectiveness is strongly limited by frequent severe adverse effects, in particular nephrotoxicity and chemotherapy-induced peripheral neuropathy. Thus, there is an urgent medical need to identify novel strategies that limit cisplatin-induced toxicity. In the present study, we show that the FDA-approved adenosine A2A receptor antagonist istradefylline (KW6002) protected from cisplatin-induced nephrotoxicity and neuropathic pain in mice with or without tumors. Moreover, we also demonstrate that the antitumoral properties of cisplatin were not altered by istradefylline in tumor-bearing mice and could even be potentiated. Altogether, our results support the use of istradefylline as a valuable preventive approach for the clinical management of patients undergoing cisplatin treatment.


Asunto(s)
Antineoplásicos , Neuralgia , Animales , Ratones , Cisplatino/efectos adversos , Purinas/farmacología , Neuralgia/inducido químicamente , Receptor de Adenosina A2A , Antineoplásicos/efectos adversos
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