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1.
Mol Cell ; 84(5): 967-980.e10, 2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38242130

RESUMEN

Histone-modifying enzymes depend on the availability of cofactors, with acetyl-coenzyme A (CoA) being required for histone acetyltransferase (HAT) activity. The discovery that mitochondrial acyl-CoA-producing enzymes translocate to the nucleus suggests that high concentrations of locally synthesized metabolites may impact acylation of histones and other nuclear substrates, thereby controlling gene expression. Here, we show that 2-ketoacid dehydrogenases are stably associated with the Mediator complex, thus providing a local supply of acetyl-CoA and increasing the generation of hyper-acetylated histone tails. Nitric oxide (NO), which is produced in large amounts in lipopolysaccharide-stimulated macrophages, inhibited the activity of Mediator-associated 2-ketoacid dehydrogenases. Elevation of NO levels and the disruption of Mediator complex integrity both affected de novo histone acetylation within a shared set of genomic regions. Our findings indicate that the local supply of acetyl-CoA generated by 2-ketoacid dehydrogenases bound to Mediator is required to maximize acetylation of histone tails at sites of elevated HAT activity.


Asunto(s)
Histonas , Óxido Nítrico , Histonas/genética , Histonas/metabolismo , Acetilcoenzima A/metabolismo , Acetilación , Óxido Nítrico/metabolismo , Complejo Mediador/metabolismo , Oxidorreductasas/metabolismo
2.
Genes Dev ; 37(21-24): 1017-1040, 2023 Dec 26.
Artículo en Inglés | MEDLINE | ID: mdl-38092518

RESUMEN

Transcription termination pathways mitigate the detrimental consequences of unscheduled promiscuous initiation occurring at hundreds of thousands of genomic cis-regulatory elements. The Restrictor complex, composed of the Pol II-interacting protein WDR82 and the RNA-binding protein ZC3H4, suppresses processive transcription at thousands of extragenic sites in mammalian genomes. Restrictor-driven termination does not involve nascent RNA cleavage, and its interplay with other termination machineries is unclear. Here we show that efficient termination at Restrictor-controlled extragenic transcription units involves the recruitment of the protein phosphatase 1 (PP1) regulatory subunit PNUTS, a negative regulator of the SPT5 elongation factor, and Symplekin, a protein associated with RNA cleavage complexes but also involved in cleavage-independent and phosphatase-dependent termination of noncoding RNAs in yeast. PNUTS and Symplekin act synergistically with, but independently from, Restrictor to dampen processive extragenic transcription. Moreover, the presence of limiting nuclear levels of Symplekin imposes a competition for its recruitment among multiple transcription termination machineries, resulting in mutual regulatory interactions. Hence, by synergizing with Restrictor, Symplekin and PNUTS enable efficient termination of processive, long-range extragenic transcription.


Asunto(s)
ARN Polimerasa II , Transcripción Genética , Animales , ARN Polimerasa II/metabolismo , Secuencias Reguladoras de Ácidos Nucleicos , Proteínas de Unión al ARN/metabolismo , Procesamiento Proteico-Postraduccional , Mamíferos/genética
3.
J Neuroeng Rehabil ; 19(1): 97, 2022 09 10.
Artículo en Inglés | MEDLINE | ID: mdl-36088387

RESUMEN

BACKGROUND: Numerous studies showed that postural balance improves through light touch on a stable surface highlighting the importance of haptic information, seemingly downplaying the mechanical contributions of the support. The present study examined the mechanical effects of canes for assisting balance in healthy individuals challenged by standing on a beam. METHODS: Sixteen participants supported themselves with two canes, one in each hand, and applied minimal, preferred, or maximum force onto the canes. They positioned the canes in the frontal plane or in a tripod configuration. Statistical analysis used a linear mixed model to evaluate the effects on the center of pressure and the center of mass. RESULTS: The canes significantly reduced the variability of the center of pressure and the center of mass to the same level as when standing on the ground. Increasing the exerted force beyond the preferred level yielded no further benefits, although in the preferred force condition, participants exploited the altered mechanics by resting their arms on the canes. The tripod configuration allowed for larger variability of the center of pressure in the task-irrelevant anterior-posterior dimension. High forces had a destabilizing effect on the canes: the displacement of the hand on the cane handle increased with the force. CONCLUSIONS: Given this static instability, these results show that using canes can provide not only mechanical benefits but also challenges. From a control perspective, effort can be reduced by resting the arms on the canes and by channeling noise in the task-irrelevant dimensions. However, larger forces exerted onto the canes can also have destabilizing effects and the instability of the canes needs to be counteracted, possibly by arm and shoulder stiffness. Insights into the variety of mechanical effects is important for the design of canes and the instructions of how to use them.


Asunto(s)
Postura , Posición de Pie , Brazo , Mano , Humanos , Equilibrio Postural
4.
J Neuroeng Rehabil ; 18(1): 145, 2021 09 25.
Artículo en Inglés | MEDLINE | ID: mdl-34563223

RESUMEN

BACKGROUND: Maintaining upright posture is an unstable task that requires sophisticated neuro-muscular control. Humans use foot-ground interaction forces, characterized by point of application, magnitude, and direction to manage body accelerations. When analyzing the directions of the ground reaction forces of standing humans in the frequency domain, previous work found a consistent pattern in different frequency bands. To test whether this frequency-dependent behavior provided a distinctive signature of neural control or was a necessary consequence of biomechanics, this study simulated quiet standing and compared the results with human subject data. METHODS: Aiming to develop the simplest competent and neuromechanically justifiable dynamic model that could account for the pattern observed across multiple subjects, we first explored the minimum number of degrees of freedom required for the model. Then, we applied a well-established optimal control method that was parameterized to maximize physiologically-relevant insight to stabilize the balancing model. RESULTS: If a standing human was modeled as a single inverted pendulum, no controller could reproduce the experimentally observed pattern. The simplest competent model that approximated a standing human was a double inverted pendulum with torque-actuated ankle and hip joints. A range of controller parameters could stabilize this model and reproduce the general trend observed in experimental data; this result seems to indicate a biomechanical constraint and not a consequence of control. However, details of the frequency-dependent pattern varied substantially across tested control parameter values. The set of parameters that best reproduced the human experimental results suggests that the control strategy employed by human subjects to maintain quiet standing was best described by minimal control effort with an emphasis on ankle torque. CONCLUSIONS: The findings suggest that the frequency-dependent pattern of ground reaction forces observed in quiet standing conveys quantitative information about human control strategies. This study's method might be extended to investigate human neural control strategies in different contexts of balance, such as with an assistive device or in neurologically impaired subjects.


Asunto(s)
Fenómenos Mecánicos , Modelos Biológicos , Articulación del Tobillo , Fenómenos Biomecánicos , Humanos , Equilibrio Postural , Posición de Pie
5.
J Neurophysiol ; 124(1): 295-304, 2020 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-32579415

RESUMEN

There are numerous ways to reach for an apple hanging from a tree. Yet, our motor system uses a specific muscle activity pattern that features activity bursts and silent periods. We suggest that these bursts are an evidence against the common view that the brain controls the commands to the muscles in a smooth continuous manner. Instead, we propose a model in which a motor plan is transformed into a piecewise-constant control signal that is low-pass filtered and transmitted to the muscles with different muscle-specific delays. We use a Markov chain Monte Carlo (MCMC) method to identify transitions in the state of the muscles following initial activation and show that fitting a bang-bang control model to the kinematics of movement predicts these transitions in the state of the muscles. Such a bang-bang controller suggests that the brain reduces the complexity of the problem of ballistic movements control by sending commands to the muscles at sparse times. Identifying this bang-bang controller can be useful to develop efficient controllers for neuroprostheses and other physical human-robot interaction systems.NEW & NOTEWORTHY While ballistic hand reaching movements are characterized by smooth position and velocity signals, the activity of the muscles exhibits bursts and silent periods. Here, we propose that a model based on bang-bang control provides the link between the abrupt changes in the muscle activity and the smooth reaching trajectory. Using bang-bang control instead of continuous control may simplify the design of prostheses and other physical human-robot interaction systems.


Asunto(s)
Modelos Biológicos , Actividad Motora/fisiología , Músculo Esquelético/fisiología , Adulto , Electromiografía , Humanos , Modelos Estadísticos
6.
Environ Res ; 184: 109347, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32179267

RESUMEN

BACKGROUND: Waterpipe tobacco smoking has grown in popularity worldwide, with the prevalence of use increasing in Spain from 6.2% to 10.8% in the last decade, despite the smoking ban enacted in 2010 for all hospitality premises. OBJECTIVE: To assess exposure to second-hand smoke from waterpipes based on the concentrations of airborne nicotine and particulate matter ≤2.5 µm in diameter (PM2.5) in a sample of waterpipe cafés in the city of Barcelona (Spain). METHODS: This cross-sectional study included a sample of 20 waterpipe cafés. Airborne nicotine and PM2.5 were sampled for 30 min in each venue using a nicotine sampling device connected by a tube to a pump and a TSI SidePak Personal Aerosol Monitor. Five outdoor control locations were also measured. We computed medians, interquartile ranges (IQRs), and maximum values and compared them according to venues' and sampling characteristics using the Kruskall-Wallis and U-Mann Whitney tests. Nicotine and PM2.5 were correlated by calculating the Spearman-rank correlation coefficient. RESULTS: The median concentration of nicotine and PM2.5 were 1.15 and 230.50 µg/m3 in waterpipe cafés and 0.03 and 10.00 µg/m3 in control locations (p<0.05 in both cases). The Spearman correlation coefficient between both markers was 0.61 (95% confidence interval: 0.18-0.84). No differences were found in nicotine or PM2.5 concentration according to the venues' and sampling characteristics studied, with the exception of area. After stratifying for area, venues >100 m2, located in a tourist area, with >15 lit waterpipes, >8 waterpipes/100 m2, and a ratio of 2 users per waterpipe or less had significantly higher nicotine concentration. DISCUSSION: Despite the current smoking ban, which includes hospitality venues, we found nicotine and PM2.5 levels in Barcelona waterpipe cafés that exceeded the threshold recommended by the World Health Organization. This exposure poses serious risks to the health of both workers and customers and constitutes a non-compliance of the legislation.


Asunto(s)
Contaminación del Aire Interior , Contaminación por Humo de Tabaco , Fumar en Pipa de Agua , Contaminación del Aire Interior/análisis , Ciudades , Estudios Transversales , Humanos , Nicotina/análisis , Material Particulado/análisis , Restaurantes , España , Contaminación por Humo de Tabaco/análisis
7.
J Neurophysiol ; 122(6): 2486-2503, 2019 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-31577474

RESUMEN

Overarm throwing is a fundamental human skill. Since paleolithic hunter-gatherer societies, the ability of throwing played a key role in brain and body co-evolution. For decades, throwing skill acquisition has been the subject of developmental and gender studies. However, due to its complex multijoint nature, whole body throwing has found little space in quantitative studies of motor behavior. In this study we examined how overarm throwing varies within and between individuals in a sample of untrained adults. To quantitatively compare whole body kinematics across throwing actions, we introduced a new combination of spatiotemporal principal component, linear discrimination, and clustering analyses. We found that the identity and gender of a thrower can be robustly inferred by the kinematics of a single throw, reflecting the characteristic features in individual throwing strategies and providing a quantitative ground for the well-known differences between males and females in throwing behavior. We also identified four main classes of throwing strategies, stable within individuals and resembling the main stages of throwing proficiency acquisition during motor development. These results support earlier proposals linking interindividual and gender differences in throwing, with skill acquisition interrupted at different stages of the typical developmental trajectory of throwing motor behavior.NEW & NOTEWORTHY Unconstrained throwing, because of its complexity, received little attention in quantitative motor control studies. By introducing a new approach to analyze whole body kinematics, we quantitatively characterized gender effects, interindividual differences, and common patterns in nontrained throwers. The four throwing styles identified across individuals resemble different stages in the acquisition of throwing skills during development. These results advance our understanding of complex motor skills, bridging the gap between motor control, motor development, and sport science.


Asunto(s)
Desarrollo Humano/fisiología , Aprendizaje/fisiología , Actividad Motora/fisiología , Destreza Motora/fisiología , Adulto , Fenómenos Biomecánicos , Femenino , Humanos , Individualidad , Masculino , Factores Sexuales , Adulto Joven
8.
J Neurophysiol ; 118(4): 2421-2434, 2017 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-28768737

RESUMEN

To accurately time motor responses when intercepting falling balls we rely on an internal model of gravity. However, whether and how such a model is also used to estimate the spatial location of interception is still an open question. Here we addressed this issue by asking 25 participants to intercept balls projected from a fixed location 6 m in front of them and approaching along trajectories with different arrival locations, flight durations, and gravity accelerations (0g and 1g). The trajectories were displayed in an immersive virtual reality system with a wide field of view. Participants intercepted approaching balls with a racket, and they were free to choose the time and place of interception. We found that participants often achieved a better performance with 1g than 0g balls. Moreover, the interception points were distributed along the direction of a 1g path for both 1g and 0g balls. In the latter case, interceptions tended to cluster on the upper half of the racket, indicating that participants aimed at a lower position than the actual 0g path. These results suggest that an internal model of gravity was probably used in predicting the interception locations. However, we found that the difference in performance between 1g and 0g balls was modulated by flight duration, the difference being larger for faster balls. In addition, the number of peaks in the hand speed profiles increased with flight duration, suggesting that visual information was used to adjust the motor response, correcting the prediction to some extent.NEW & NOTEWORTHY Here we show that an internal model of gravity plays a key role in predicting where to intercept a fast-moving target. Participants also assumed an accelerated motion when intercepting balls approaching in a virtual environment at constant velocity. We also show that the role of visual information in guiding interceptive movement increases when more time is available.


Asunto(s)
Gravitación , Mano/fisiología , Percepción de Movimiento , Movimiento , Percepción Espacial , Aceleración , Adolescente , Adulto , Femenino , Sensación de Gravedad , Mano/inervación , Humanos , Masculino , Realidad Virtual
10.
BMC Cancer ; 15: 808, 2015 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-26508446

RESUMEN

BACKGROUND: The anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (moAbs) cetuximab or panitumumab are administered to colorectal cancer (CRC) patients who harbor wild-type RAS proto-oncogenes. However, a percentage of patients do not respond to this treatment. In addition to mutations in the RAS genes, mutations in other genes, such as BRAF, PI3KCA, or PTEN, could be involved in the resistance to anti-EGFR moAb therapy. METHODS: In order to develop a comprehensive approach for the detection of mutations and to eventually identify other genes responsible for resistance to anti-EGFR moAbs, we investigated a panel of 21 genes by parallel sequencing on the Ion Torrent Personal Genome Machine platform. We sequenced 65 CRCs that were treated with cetuximab or panitumumab. Among these, 37 samples were responsive and 28 were resistant. RESULTS: We confirmed that mutations in EGFR-pathway genes (KRAS, NRAS, BRAF, PI3KCA) were relevant for conferring resistance to therapy and could predict response (p = 0.001). After exclusion of KRAS, NRAS, BRAF and PI3KCA combined mutations could still significantly associate to resistant phenotype (p = 0.045, by Fisher exact test). In addition, mutations in FBXW7 and SMAD4 were prevalent in cases that were non-responsive to anti-EGFR moAb. After we combined the mutations of all genes (excluding KRAS), the ability to predict response to therapy improved significantly (p = 0.002, by Fisher exact test). CONCLUSIONS: The combination of mutations at KRAS and at the five gene panel demonstrates the usefulness and feasibility of multigene sequencing to assess response to anti-EGFR moAbs. The application of parallel sequencing technology in clinical practice, in addition to its innate ability to simultaneously examine the genetic status of several cancer genes, proved to be more accurate and sensitive than the presently in use traditional approaches.


Asunto(s)
Anticuerpos Monoclonales Humanizados/uso terapéutico , Biomarcadores de Tumor/genética , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/genética , Receptores ErbB/antagonistas & inhibidores , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Monoclonales Humanizados/farmacología , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Cetuximab/farmacología , Cetuximab/uso terapéutico , Neoplasias Colorrectales/diagnóstico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Panitumumab , Valor Predictivo de las Pruebas , Resultado del Tratamiento
11.
Comput Methods Programs Biomed ; 251: 108217, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38744059

RESUMEN

BACKGROUND AND OBJECTIVE: A new direction in the study of motor control was opened about two decades ago with the introduction of a model for the generation of motor commands as combination of muscle synergies. Muscle synergies provide a simple yet quantitative framework for analyzing the hierarchical and modular architecture of the human motor system. However, to gain insights on the functional role of muscle synergies, they should be related to the task space. The recently introduced mixed-matrix factorization (MMF) algorithm extends the standard approach for synergy extraction based on non-negative matrix factorization (NMF) allowing to factorize data constituted by a mixture of non-negative variables (e.g. EMGs) and unconstrained variables (e.g. kinematics, naturally including both positive and negative values). The kinematic-muscular synergies identified by MMF provide a direct link between muscle synergies and the task space. In this contribution, we support the adoption of MMF through a Matlab toolbox for the extraction of kinematic-muscular synergies and a set of practical guidelines to allow biomedical researchers and clinicians to exploit the potential of this novel approach. METHODS: MMF is implemented in the SynergyAnalyzer toolbox using an object-oriented approach. In addition to the MMF algorithm, the toolbox includes standard methods for synergy extraction (NMF and PCA), as well as methods for pre-processing EMG and kinematic data, and for plotting data and synergies. RESULTS: As an example of MMF application, kinematic-muscular synergies were extracted from EMG and kinematic data collected during reaching movements towards 8 targets on the sagittal plane. Instructions and command lines to achieve such results are illustrated in detail. The toolbox has been released as an open-source software on GitHub under the GNU General Public License. CONCLUSIONS: Thanks to its ease of use and adaptability to a variety of datasets, SynergyAnalyzer will facilitate the adoption of MMF to extract kinematic-muscular synergies from mixed EMG and kinematic data, a useful approach in biomedical research to better understand and characterize the functional role of muscle synergies.


Asunto(s)
Algoritmos , Electromiografía , Músculo Esquelético , Humanos , Fenómenos Biomecánicos , Electromiografía/métodos , Músculo Esquelético/fisiología , Programas Informáticos
12.
Brain Sci ; 14(5)2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38790454

RESUMEN

Rotenone is a pesticide used in research for its ability to induce changes similar, in vivo and in vitro, to those observed in Parkinson's disease (PD). This includes a selective death of dopaminergic neurons in the substantia nigra. Nonetheless, the precise mechanism through which rotenone modifies structure and function of neurons remains unclear. The PC12 cells closely resemble dopamine terminal neurons. This makes it a preferred model for studying the morphology of central dopamine neurons and predicting neurotoxicity. In this paper, we investigated the effects of 0.5 µM rotenone for 24-48 h on PC12 cell viability and ultrastructure (TEM), trying to identify primary and more evident alterations that can be related to neuronal damages similar to that seen in animal PD models. Cell viability decreased after 24 h rotenone treatment, with a further decrease after 48 h. Ultrastructural changes included vacuolar degeneration, mitochondrial mild swelling, decrease in the number of neuropeptide granules, and the loss of cell-to-cell adhesion. These findings are in agreement with previous research suggesting that rotenone, by inhibiting energy production and increasing ROS generation, is responsible for significant alterations of the ultrastructure and cell death of PC12 cells. Our data confirm the link between rotenone exposure, neuronal damage, and changes in dopamine metabolism, suggesting its role in the pathogenesis of PD.

13.
Front Endocrinol (Lausanne) ; 14: 1272646, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37842307

RESUMEN

Inflammation-dependent changes in gene expression programs in innate immune cells, such as macrophages, involve extensive reprogramming of metabolism. This reprogramming is essential for the production of metabolites required for chromatin modifications, such as acetyl-CoA, and regulate their usage and availability impacting the macrophage epigenome. One of the most transcriptionally induced proinflammatory mediator is nitric oxide (NO), which has been shown to inhibit key metabolic enzymes involved in the production of these metabolites. Recent evidence indicates that NO inhibits mitochondrial enzymes such as pyruvate dehydrogenase (PDH) in macrophages induced by inflammatory stimulus. PDH is involved in the production of acetyl-CoA, which is essential for chromatin modifications in the nucleus, such as histone acetylation. In addition, acetyl-CoA levels in inflamed macrophages are regulated by ATP citrate lyase (ACLY) and citrate transporter SLC25A1. Interestingly, acetyl-CoA producing enzymes, such as PDH and ACLY, have also been reported to be present in the nucleus and to support the local generation of cofactors such as acetyl-CoA. Here, we will discuss the mechanisms involved in the regulation of acetyl-CoA production by metabolic enzymes, their inhibition by prolonged exposure to inflammation stimuli, their involvement in dynamic inflammatory expression changes and how these emerging findings could have significant implications for the design of novel therapeutic approaches.


Asunto(s)
ATP Citrato (pro-S)-Liasa , Epigénesis Genética , Humanos , Acetilcoenzima A/metabolismo , ATP Citrato (pro-S)-Liasa/genética , ATP Citrato (pro-S)-Liasa/metabolismo , Inflamación/genética , Aciltransferasas/genética , Cromatina
14.
Hum Mov Sci ; 92: 103148, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37708594

RESUMEN

In the last two decades, muscle synergies analysis has been commonly used to assess the neurophysiological mechanisms underlying human motor control. Several synergy models and algorithms have been employed for processing the electromyographic (EMG) signal, and it has been shown that the coordination of motor control is characterized by the presence of phasic (movement-related) and tonic (anti-gravity and related to co-contraction) EMG components. Neural substrates indicate that phasic and tonic components have non-homogeneous origin; however, it is still unclear if these components are generated by the same set of synergies or by distinct synergies. This study aims at testing whether phasic and tonic components are generated by distinct phasic and tonic synergies or by the same set of synergies with phasic and tonic activation coefficients. The study also aims at characterizing the differences between the phasic and the tonic synergies. Using a comprehensive mapping of upper-limb point-to-point movements, synergies were extracted from phasic and tonic EMG signal separately, estimating the tonic components with a linear ramp model. The goodness of reconstruction (R2) as a function of the number of synergies was compared, and sets of synergies extracted from each dataset at three R2 threshold levels (0.80, 0.85, 0.90) were retained for further analysis. Then, shared, phasic-specific, and tonic-specific synergies were extracted from the two datasets concatenated. The dimensionality of the synergies shared between the phasic and the tonic datasets was estimated with a bootstrap procedure based on the evaluation of the distribution of principal angles between the subspaces spanned by phasic and tonic synergies due to noise. We found only few shared synergies, indicating that phasic and tonic synergies have in general different structures. To compare consistent differences in synergy composition, shared, phasic-specific, and tonic-specific synergies were clustered separately. Phasic-specific clusters were more numerous than tonic-specific ones, suggesting that they were more differentiated among subjects. The structure of phasic clusters and the higher sparseness indicated that phasic synergies capture specific muscle activation patterns related to the movement while tonic synergies show co-contraction of multiple muscles for joint stabilization and holding postures. These results suggest that in many scenarios phasic and tonic synergies should be extracted separately, especially when performing muscle synergy analysis in patients with abnormal tonic activity and for tuning devices with gravity support.


Asunto(s)
Movimiento , Músculo Esquelético , Humanos , Músculo Esquelético/fisiología , Electromiografía/métodos , Movimiento/fisiología , Postura/fisiología , Extremidad Superior
15.
iScience ; 26(8): 107395, 2023 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-37554449

RESUMEN

This simulation study investigated whether a 4-degrees-of-freedom (DOF) arm could strike a target with a 50-DOF whip using a motion profile similar to discrete human movements. The interactive dynamics of the multi-joint arm was modeled as a constant joint-space mechanical impedance, with values derived from experimental measurement. Targets at various locations could be hit with a single maximally smooth motion in joint-space coordinates. The arm movements that hit the targets were identified with fewer than 250 iterations. The optimal actions were essentially planar arm motions in extrinsic task-space coordinates, predominantly oriented along the most compliant direction of both task-space and joint-space mechanical impedances. Of the optimal movement parameters, striking a target was most sensitive to movement duration. This result suggests that the elementary actions observed in human motor behavior may support efficient motor control in interaction with a dynamically complex object.

16.
iScience ; 26(2): 106038, 2023 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-36824276

RESUMEN

Prediction is critical for successful interactions with a dynamic environment. To test the development of predictive processes over the life span, we designed a suite of interceptive tasks implemented as interactive video games. Four tasks involving interactions with a flying ball with titrated challenge quantified spatiotemporal aspects of prediction. For comparison, reaction time was assessed in a matching task. The experiments were conducted in a museum, where over 400 visitors across all ages participated, and in a laboratory with a focused age group. Results consistently showed that predictive ability improved with age to reach adult level by age 12. In contrast, reaction time continued to decrease into late adolescence. Inter-task correlations revealed that the tasks tested different aspects of predictive processes. This developmental progression complements recent findings on cerebellar and cortical maturation. Additionally, these results can serve as normative data to study predictive processes in individuals with neurodevelopmental conditions.

17.
R Soc Open Sci ; 9(10): 220581, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36249337

RESUMEN

Humans are strikingly adept at manipulating complex objects, from tying shoelaces to cracking a bullwhip. These motor skills have highly nonlinear interactive dynamics that defy reduction into parts. Yet, despite advances in data recording and processing, experiments in motor neuroscience still prioritize experimental reduction over realistic complexity. This study embraced the fully unconstrained behaviour of hitting a target with a 1.6-m bullwhip, both in rhythmic and discrete fashion. Adopting an object-centered approach to test the hypothesis that skilled movement simplifies the whip dynamics, the whip's evolution was characterized in relation to performance error and hand speed. Despite widely differing individual strategies, both discrete and rhythmic styles featured a cascade-like unfolding of the whip. Whip extension and orientation at peak hand speed predicted performance error, at least in the rhythmic style, suggesting that humans accomplished the task by setting initial conditions. These insights may inform further studies on human and robot control of complex objects.

18.
J Cell Biol ; 220(3)2021 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-33566069

RESUMEN

The commitment of mesenchymal stem cells to preadipocytes is stimulated by hormonal induction. Preadipocytes induced to differentiate repress protein synthesis, remodel their cytoskeleton, and increase mitochondrial function to support anabolic pathways. These changes enable differentiation into mature adipocytes. Our understanding of the factors that coordinately regulate the early events of adipocyte differentiation remains incomplete. Here, by using multipronged approaches, we have identified zinc finger CCCH-type containing 10 (Zc3h10) as a critical regulator of the early stages of adipogenesis. Zc3h10 depletion in preadipocytes resulted in increased protein translation and impaired filamentous (F)-actin remodeling, with the latter detrimental effect leading to mitochondrial and metabolic dysfunction. These defects negatively affected differentiation to mature adipocytes. In contrast, Zc3h10 overexpression yielded mature adipocytes with remarkably increased lipid droplet size. Overall, our study establishes Zc3h10 as a fundamental proadipogenic transcription factor that represses protein synthesis and promotes F-actin/mitochondria dynamics to ensure proper energy metabolism and favor lipid accumulation.


Asunto(s)
Actinas/metabolismo , Adipogénesis , Mitocondrias/metabolismo , Biosíntesis de Proteínas , Proteínas de Unión al ARN/metabolismo , Citoesqueleto de Actina/metabolismo , Adipocitos/metabolismo , Adipogénesis/genética , Tejido Adiposo Blanco/metabolismo , Animales , Línea Celular , Ciclo del Ácido Cítrico , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Metabolismo Energético/genética , Regulación de la Expresión Génica , Metabolismo de los Lípidos/genética , Masculino , Metaboloma , Ratones Endogámicos C57BL , Dinámicas Mitocondriales , Precursores del ARN/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/genética , Transcriptoma/genética , Proteínas de Unión al GTP rho/metabolismo
19.
Nat Struct Mol Biol ; 28(4): 337-346, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33767452

RESUMEN

Interactions between the splicing machinery and RNA polymerase II increase protein-coding gene transcription. Similarly, exons and splicing signals of enhancer-generated long noncoding RNAs (elncRNAs) augment enhancer activity. However, elncRNAs are inefficiently spliced, suggesting that, compared with protein-coding genes, they contain qualitatively different exons with a limited ability to drive splicing. We show here that the inefficiently spliced first exons of elncRNAs as well as promoter-antisense long noncoding RNAs (pa-lncRNAs) in human and mouse cells trigger a transcription termination checkpoint that requires WDR82, an RNA polymerase II-binding protein, and its RNA-binding partner of previously unknown function, ZC3H4. We propose that the first exons of elncRNAs and pa-lncRNAs are an intrinsic component of a regulatory mechanism that, on the one hand, maximizes the activity of these cis-regulatory elements by recruiting the splicing machinery and, on the other, contains elements that suppress pervasive extragenic transcription.


Asunto(s)
Proteínas Cromosómicas no Histona/genética , Proteínas de Unión al ADN/genética , ARN Polimerasa II/ultraestructura , ARN Largo no Codificante/genética , Transcripción Genética , Empalme Alternativo/genética , Animales , Proteínas Cromosómicas no Histona/ultraestructura , Proteínas de Unión al ADN/ultraestructura , Exones/genética , Humanos , Ratones , Regiones Promotoras Genéticas/genética , ARN Polimerasa II/genética , Empalme del ARN/genética , ARN sin Sentido/genética , ARN sin Sentido/ultraestructura , ARN Largo no Codificante/ultraestructura , ARN Mensajero/genética , Secuencias Reguladoras de Ácidos Nucleicos/genética
20.
Front Cell Neurosci ; 13: 356, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31417369

RESUMEN

Frataxin deficiency is the pathogenic cause of Friedreich's Ataxia, an autosomal recessive disease characterized by the increase of oxidative stress and production of free radicals in the cell. Although the onset of the pathology occurs in the second decade of life, cognitive differences and defects in brain structure and functional activation are observed in patients, suggesting developmental defects to take place during fetal neurogenesis. Here, we describe impairments in proliferation, stemness potential and differentiation in neural stem cells (NSCs) isolated from the embryonic cortex of the Frataxin Knockin/Knockout mouse, a disease animal model whose slow-evolving phenotype makes it suitable to study pre-symptomatic defects that may manifest before the clinical onset. We demonstrate that enhancing the expression and activity of the antioxidant response master regulator Nrf2 ameliorates the phenotypic defects observed in NSCs, re-establishing a proper differentiation program.

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