Muscle actin isoforms are differentially expressed in human satellite cells isolated from donors of different ages

Abstract

Myogenesis is mainly sustained by a subpopulation of myogenic cells known as satellite cells (SC). In this paper we studied alpha-smooth muscle (alphaSMA) and alpha-sarcomeric muscle (alphaSRA) actin isoform expression in cultures of human satellite cells (HSC) isolated from skeletal muscle biopsies from a 5-day-old newborn, a 34-year-old young adult and a 71-year-old donor. Myogenicity of cultures was assessed using immunocytochemical detection of desmin and myosin heavy chain. Time-course expression of alphaSRA and alphaSMA were studied with both immunocytochemistry and western blotting procedures. Although alphaSMA was never detected in whole skeletal muscle, both alphaSMA and alphaSRA were detected in proliferating and differentiating HSC derived from donors of all examined ages. The expression level experiments showed that alphaSRA was gradually up-regulated during HSC differentiation, but no significant differences were observed between newborn, young, and elderly HSC cultures. Our data demonstrated that HSC, isolated from subjects of different ages, re-expressed alphaSMA, but its levels and expression pattern varied considerably in the newborn with respect to the young adult and elderly donors. These results are discussed in relation to the myogenic differentiation capability of HSC during human muscle senescence.

Barx2 Is Expressed in Satellite Cells and Is Required for Normal Muscle Growth and Regeneration

“…5A, red arrows). The “rounded” and “flattened” myoblasts were examined in more detail by confocal imaging after staining with antibodies to smooth muscle actin (SMA), which is expressed transiently in undifferentiated myoblasts [41, 60]. The flattened morphology was associated with cell spreading, filamentous actin redistribution, and increased numbers of cell surface protrusions (Fig.…”

Does skeletal muscle have an ‘epi’‐memory? The role of epigenetics in nutritional programming, metabolic disease, aging and exercise

“…More recently, this concept has been confirmed and discussed by four further papers (three original works and one review), again collectively suggesting that muscle‐derived cells retain a ‘memory’ of negative encounters once isolated from different environmental niches, where (i) muscle‐derived cells from obese patients do not respond to lipid oversupply with the same gene expression signatures vs. control (Maples & Brault, ); (ii) muscle‐derived cells from intrauterine growth‐restricted sheep foetuses exhibit deficiencies in proliferation vs. controls (Yates et al ., ); (iiii) skeletal muscle stem cells isolated from prenatal 50% global nutrient‐restricted mice offspring or early postnatal high‐fat diet (60% of total calories from fat) offspring have a reduced number of muscle precursor cells and a 32% decrease in the capacity of these cells to regenerate after injury (Woo et al ., ). Interestingly, in the same study it was reported that a high‐fat diet also evoked reductions in the number of muscle stem cells retrieved from skeletal muscle tissue and was associated with larger reductions (44%) in regeneration (chow 16% vs. high‐fat diet 9%), suggesting that the environment in which the muscle cells were derived could be remembered and subsequently affect the muscle repair and regeneration in later life (Woo et al ., ); (iv) finally, the vast majority of aged muscle stem cells isolated from aged animals and humans or those replicatively aged in culture have an impaired or delayed differentiation/regenerative capacity (Allen et al ., ; Charge et al ., ; Lorenzon et al ., ; Lees et al ., ; Carlson & Conboy, ; Lancioni et al ., ; Bigot et al ., ; Hidestrand et al ., ; Pietrangelo et al ., ; Beccafico et al ., ; Sharples et al ., , , ; Kandalla et al ., ; Merritt et al ., ; Zwetsloot et al ., ) or display delayed differentiation (Corbu et al ., ). Very few studies showed no impact of age on differentiation of the isolated muscle stem cells (Shefer et al ., ; Alsharidah et al ., ); where even these studies reported aged muscle to have fewer stem cells to begin with (Shefer et al ., ).…”

DNA methylation across the genome in aged human skeletal muscle tissue and stem cells: The role of HOX genes and physical activity

“…This included altered methylation of MyoD 24 , Myogenin 25 and Six1 26 . While muscle stem cells derived from aged individuals display similar proliferative capacity and time to senescence as young adult cells 27,28 , they do have impaired differentiation and fusion into myotubes 29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45 . However, a small number of studies did not find an effect of age on the differentiation capacity of isolated cells 27,46,47 .…”