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Satellite cells and exercise
Published in Adam P. Sharples, James P. Morton, Henning Wackerhage, Molecular Exercise Physiology, 2022
Neil R.W. Martin, Adam P. Sharples
Several experiments have provided evidence that the satellite cell niche (i.e. the muscle fibre itself) and the systemic environment contribute to the observed loss of satellite cell function in aged muscle. Transplantation of extensor digitorum longus muscles from old rats into young rats improves the recovery of muscle mass and force in the regenerating tissue compared with transplantation into an old host animal. Conversely, transplanting young muscle to an old host animal worsens regeneration (155). Heterochronic parabiosis studies, where the circulatory systems of young and old animals are surgically joined together, provide further evidence that the ageing environment is detrimental to satellite cell function. When old mice are joined with young mice prior to muscle injury, the old mice are able to mount a regenerative response which far exceeds the normal response of aged muscle (156). Conversely, young mice joined with old mice suffer more fibrosis during regeneration and reduced satellite cell proliferation (157). Furthermore, a recent study found that more than 50% of the genes that change in satellite cells with ageing can be returned to young levels when exposed to a young niche (158). Collectively, this suggests that exposure to a ‘young’ environment can help towards rejuventating aged satellite cells.
Aging Epigenetics
Published in Shamim I. Ahmad, Aging: Exploring a Complex Phenomenon, 2017
Vasily V. Ashapkin, Lyudmila I. Kutueva, Boris F. Vanyushin
Aging is generally believed to be an inevitable and essentially irreversible process in all living organisms. However, multiple studies described above have shown that it could be completely reversed at the cellular level and reversed to a considerable extent at the organismal level. First, cellular reprogramming has been shown to reset the age of somatic cells to zero. Second, on the whole organism level, manipulations of specific signaling pathways (insulin/IGF-1, mTOR, AMPK, and sirtuins) and external interventions (CR and physical activity) were shown to extend the life span of model animals, probably by slowing down the aging process. Third, the heterochronic parabiosis experiments have shown that, at the organismal level, aging not only could be slowed down but also reversed to a significant extent, at least in some organs. It would be interesting to determine whether these rejuvenating effects of parabiosis are caused by epigenetic changes.
Psychobiological foundations of early sensory-motor development and implications for neonatal care
Published in Philip N. Murphy, The Routledge International Handbook of Psychobiology, 2018
Victoria Dumont, Maryse Delaunay-El Allam, Nadège Roche-Labarbe
In mammals, somatosensation and chemosensation are the first sensory systems by which the developing organism becomes acquainted with its environment (Segond, 2008). Somatosensory perception includes tactile, thermal and pain perception through cutaneous receptors, as well as postural and movement information through muscle and tendon receptors. Chemosensory perception includes the olfactory, gustatory and trigeminal systems, involved in nutrition, social interactions, and emotional reactivity and regulation. In humans, these two systems emerge in utero and prepare the foetus for postnatal life. Because of this developmental heterochrony, they are the foundation of cognitive and affective development (Humphrey, 1970; Lecanuet & Schaal, 1996; Schaal, 2000; Schaal, Hummel, & Soussignan, 2004). Although the importance of these ontogenetically and phylogenetically earlier systems for individual development has been acknowledged for a long time, they are the least studied in the human neonate, compared with later modalities such as hearing (Fitzgerald & Andrews, 1994; Streri, Hevia, Izard, & Coubart, 2013). Clinicians dealing with premature and other fragile newborns have initiated a renewal of interest in these perceptions by suggesting therapeutic interventions in these modalities, but their efforts are impeded by the lack of basic knowledge that could drive their hypotheses and frame their observations. In this chapter, we propose a framework to study neonatal psychobiological development focusing on tactile and chemical senses. We want to emphasize how these senses are crucial modalities to understand very early development, and how they can bring rational arguments and testable hypotheses to the growing field of sensory therapies and developmental care in preterm and term neonates. We hope that these modalities will attract more attention from both researchers and clinicians in the future.
A Representational Approach to Executive Function Impairments in Young Adults with Down Syndrome
Published in Developmental Neuropsychology, 2020
Lydie Iralde, Arnaud Roy, Juliette Detroy, Philippe Allain
That said, and consistent with Grafman’s theoretical framework (1989; 1999; 2002), the fact that individuals with DS did not make a higher number of intrusion errors could be also explained by a comparable ability to access script information at a similar mental age. In other words, the basic representation of the script in the memory seems to be somewhat preserved in DS, compared with control children (MAG). Similarly, the fact that participants with DS produce significantly fewer closing errors than MAG and, more generally, fewer category 2 arguments, could support Grafman’s (e.g., 2002) proposal here, with the advantage of a longer social life (i.e., they are chronologically older and therefore have an advantage as they possess a certain amount of knowledge that the standard children of the same mental age have not yet acquired). Here, we find a classic observation illustrating the phenomenon of developmental heterochrony that is classically associated with intellectual disability (e.g., Zazzo, 1979). It should be noted however that the rejection of the target actions in the scripts is only observed in the group with DS: even if the majority of the participants do not show this behavior, this difference is significant regardless of which groups were being compared (neither the adult nor child control groups excluded any of the target items). As a result, even if the representation of the script (i.e., the semantic dimension) is fairly well preserved in subjects with DS, it may still be possible to observe DS-related particularities.
BCL11A Down-Regulation Induces γ-Globin in Human β-Thalassemia Major Erythroid Cells
Published in Hemoglobin, 2018
Jing Li, Yongrong Lai, Lingling Shi
Heterochronic factors include the LIN28 and IGF2BP families of RNA-binding factors, and the let-7 family of microRNAs (miRNAs). Depletion of let-7 miRNAs, as well as over expression of their regulator LIN28, in adult CD34+, hematopoietic stem and progenitor cells (HSPCs) result in elevated γ-globin expression [23]. Over expression of the heterochronic let-7 targets HMGA2, IGF2BP3 and, most dramatically, IGF2BP1 results in HbF induction in primary adult erythroblasts [24,25]. Expression of the LIN28B and IGF2BP1 appear to reduce BCL11A expression, however, the mechanism of BCL11A inhibition still needs further validation and investigation.
Synaptic remodeling, lessons from C. elegans
Published in Journal of Neurogenetics, 2020
Andrea Cuentas-Condori, David M. Miller, 3rd
The stereotypical occurrence of DD remodeling during a specific developmental period (i.e. L1 stage larvae) points to regulation by a genetic program (White et al., 1978). This idea was substantiated by the finding that the heterochronic protein, LIN-14, controls the timing of DD remodeling. The presynaptic marker, SNB-1::GFP, is precociously relocated to the dorsal nerve cord in lin-14 mutants, suggesting that LIN-14 normally prevents the premature activation of the presynaptic remodeling program (Hallam & Jin, 1998; Figure 3(A)).