scholarly journals Changes in Cellular Crosstalk between Skeletal Muscle Myoblasts and Bone Osteoblasts with Aging

2021 ◽  
Author(s):  
Jonathan A. Doering ◽  
Carly E. Britt ◽  
Gregory S. Sawicki ◽  
Jacqueline H. Cole

AbstractMusculoskeletal function declines with aging, resulting in an increased incidence of trips and falls. Both bone and muscle experience age-related losses in tissue mass that alter their mechanical interactions in a well characterized manner, but changes in the biochemical interactions between bone and muscle with aging are not well understood. Of note, insulin-like growth factor 1 (IGF-1), a potent growth factor for bone and muscle, can be negatively altered with aging and may help explain losses in these tissues. We recently developed a co-culture system for simultaneous growth of bone mesenchymal stem cells (MSCs) and muscle satellite cells (SCs) to investigate the biochemical crosstalk between the two cell types. Here, we utilized an aging rat model to study cellular changes between young and old rat MSCs and SCs, in particular whether 1) young MSCs and SCs have increased proliferation and differentiation compared to old MSCs and SCs; 2) young cells have increased IGF-1 and collagen expression as a measure of crosstalk compared to old cells; and 3) young cells can mitigate the aging phenotype of old cells in co-culture. Rat MSCs and SCs were either mono- or co-cultured in Transwell® plates, grown to confluence, and allowed to differentiate for 14 days. Across the 14 days, cell proliferation was measured, with differentiation and crosstalk measurements evaluated at 14 days. The results suggest that in both young and old, proliferation is greater in mono-cultures compared to co-cultures, yet age and cell type did not have a significant effect. Differentiation did not differ between young and old cells, yet MSCs and SCs demonstrated the greatest amount of differentiation in co-culture. Finally, age, cell type, and culture type did not have a significant effect on collagen or IGF-1 expression. These results suggest co-culture may have a controlling effect, with the two cell types acting together to promote differentiation more than in mono-cultures, yet this response was not altered by age. In general, results for old cells had higher variability, suggesting a wider variety in the aging phenotypes demonstrated in these animals. This study was the first to use this rat aging model to investigate changes between bone and skeletal muscle cells, however further investigations are required to determine what signaling changes occur in response to age. Determining these signaling changes could lead to new targets for mitigating the progression of aging.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Homer-Bouthiette ◽  
L. Xiao ◽  
Marja M. Hurley

AbstractFibroblast growth factor 2 (FGF2) is important in musculoskeletal homeostasis, therefore the impact of reduction or Fgf2 knockout on skeletal muscle function and phenotype was determined. Gait analysis as well as muscle strength testing in young and old WT and Fgf2KO demonstrated age-related gait disturbances and reduction in muscle strength that were exacerbated in the KO condition. Fgf2 mRNA and protein were significantly decreased in skeletal muscle of old WT compared with young WT. Muscle fiber cross-sectional area was significantly reduced with increased fibrosis and inflammatory infiltrates in old WT and Fgf2KO vs. young WT. Inflammatory cells were further significantly increased in old Fgf2KO compared with old WT. Lipid-related genes and intramuscular fat was increased in old WT and old Fgf2KO with a further increase in fibro-adipocytes in old Fgf2KO compared with old WT. Impaired FGF signaling including Increased β-Klotho, Fgf21 mRNA, FGF21 protein, phosphorylated FGF receptors 1 and 3, was observed in old WT and old Fgf2KO. MAPK/ ERK1/2 was significantly increased in young and old Fgf2KO. We conclude that Fgf2KO, age-related decreased FGF2 in WT mice, and increased FGF21 in the setting of impaired Fgf2 expression likely contribute to impaired skeletal muscle function and sarcopenia in mice.


2009 ◽  
Vol 296 (1) ◽  
pp. E121-E131 ◽  
Author(s):  
C. H. Widberg ◽  
F. S. Newell ◽  
A. W. Bachmann ◽  
S. N. Ramnoruth ◽  
M. C. Spelta ◽  
...  

Cell number is an important determinant of adipose tissue mass, and the coordinated proliferation and differentiation of preadipocytes into mature lipid-laden adipocytes underpins the increased adipose tissue mass associated with obesity. Despite this, the molecular cues governing such adipose tissue expansion are poorly understood. We previously reported that fibroblast growth factor-1 (FGF-1) promotes both proliferation and differentiation of human preadipocytes and that the major adipogenic effect of FGF-1 occurs during proliferation, priming the cells for adipose conversion. In the current study, we examined whether this effect was linked to the mitogenic action of FGF-1 by investigating the mitogenic and adipogenic potential of other growth factors, platelet-derived growth factor (PDGF; AA and BB) and vascular endothelial growth factor. Although PDGF-AA and PDGF-BB showed comparable mitogenic potential to FGF-1, only FGF-1 treatment resulted in priming and subsequent differentiation. Pharmacological inhibition of FGF receptor (FGFR) tyrosine kinase activity, using the FGFR-specific inhibitors PD-173074 and SU-5402, revealed an obligate requirement for FGFR activity in these processes. A combination of biochemical and genetic approaches revealed an important role for FGFR1. Knock down of FGFR1 expression by small-interfering RNA reduced FGF-1-stimulated signaling events, proliferation, and priming. Together these data highlight the unique nature of the role of FGF-1 during the earliest stages of adipogenesis and establish a role for FGFR1 in human adipogenesis, identifying FGFR1 as a potential therapeutic target to reduce obesity.


Development ◽  
1989 ◽  
Vol 106 (3) ◽  
pp. 543-554 ◽  
Author(s):  
A.L. Brice ◽  
J.E. Cheetham ◽  
V.N. Bolton ◽  
N.C. Hill ◽  
P.N. Schofield

The insulin-like growth factors are broadly distributed in the human conceptus and are thought to play a role in the growth and differentiation of tissues during development. Using in situ hybridization we have shown that a wide variety of specific cell types within tissues express the gene for insulin-like growth factor II at times of development from 18 days to 14 weeks of gestation. Examination of blastocysts produced by in vitro fertilization showed no expression, thus bracketing the time of first accumulation of IGF-II mRNA to between 5 and 18 days postfertilization. The pattern of IGF-II expression shows specific age-related differences in different tissues. In the kidney, for example, expression is found in the cells of the metanephric blastema which is dramatically reduced as the blastema differentiates. The reverse is also seen, and we have noted an increase in expression of IGF-II in the cytotrophoblast layer of the placenta with gestational age. The sites of expression do not correlate with areas of either high mitotic activity or specific types of differentiation, but the observed pattern of expression in the kidney, adrenal glands and liver suggests an explanation for the abnormally high IGF-II mRNA expression in developmental tumours such as Wilms' tumour.


Author(s):  
Isaac E. Erickson ◽  
Steven C. van Veen ◽  
Swarnali Sengupta ◽  
Sydney R. Kestle ◽  
Jason A. Burdick ◽  
...  

Articular cartilage pathology is common in the aged population. Numerous studies have shown that aged chondrocytes (CHs) are inferior to juvenile CHs in their ability to proliferate and produce cartilage-specific extracellular matrix proteins, potentially limiting their use in tissue engineering applications for cartilage restoration [1,2]. Mesenchymal stem cells (MSCs) are an alternative cell type that can be expanded in vitro while maintaining their ability to differentiate into cell types comparable to articular chondrocytes. However, organismal aging also influences human MSC proliferation [3,4] and multi-potential differentiation [5], though for chondrogenesis these findings are mixed, with some suggesting that aged progenitor cells retain their chondrogenic capacity [6]. The objective of this study was to assess age related differences in donor-matched CH and MSC potential for chondrogenic repair. In addition, the effects of the chondrogenic growth factor TGF-β3 on CHs and MSCs were evaluated.


Author(s):  
J.M. Brameld ◽  
P.A. Weller ◽  
R.S. Gilmour ◽  
P.J. Buttery

Many of the effects of growth hormone are now thought to be mediated via the stimulation of insulin-like growth factor-I (IGF-I) production by many tissues, especially the liver, with this stimulation being dependent upon the presence of the GH-receptor (GHR). IGF-I gene expression occurs via alternative promoters giving rise to class 1 and 2 transcripts, of which class 2 is thought to be preferentially responsive to GH (Saunders, Dickson, Pell & Gilmour, 1991).The effects of IGF-I include the stimulation of DNA synthesis (mitogenesis) and protein synthesis in most cell types, together with the differentiation of many cell types into mature tissue, including the differentiation of muscle cells into muscle fibres. Thus the GH/IGF-I axis has been found to play a major part in the control of animal growth. For this reason, we studied the age related changes in IGF-I and GHR mRNA expression in pig liver and skeletal muscle.


2014 ◽  
Vol 306 (2) ◽  
pp. E150-E156 ◽  
Author(s):  
Mara Fornaro ◽  
Aaron C. Hinken ◽  
Saul Needle ◽  
Erding Hu ◽  
Anne-Ulrike Trendelenburg ◽  
...  

A splice form of IGF-1, IGF-1Eb, is upregulated after exercise or injury. Physiological responses have been ascribed to the 24-amino acid COOH-terminal peptide that is cleaved from the NH3-terminal 70-amino acid mature IGF-1 protein. This COOH-terminal peptide was termed “mechano-growth factor” (MGF). Activities claimed for the MGF peptide included enhancing muscle satellite cell proliferation and delaying myoblast fusion. As such, MGF could represent a promising strategy to improve muscle regeneration. Thus, at our two pharmaceutical companies, we attempted to reproduce the claimed effect of MGF peptides on human and mouse muscle myoblast proliferation and differentiation in vitro. Concentrations of peptide up to 500 ng/ml failed to increase the proliferation of C2C12 cells or primary human skeletal muscle myoblasts. In contrast, all cell types exhibited a proliferative response to mature IGF-1 or full-length IGF-1Eb. MGF also failed to inhibit the differentiation of myoblasts into myotubes. To address whether the response to MGF was lost in these tissue culture lines, we measured proliferation and differentiation of primary mouse skeletal muscle stem cells exposed to MGF. This, too, failed to demonstrate a significant effect. Finally, we tested whether MGF could alter a separate documented in vitro effect of the peptide, activation of p-ERK, but not p-Akt, in cardiac myocytes. Although a robust response to IGF-1 was observed, there were no demonstrated activating responses from the native or a stabilized MGF peptide. These results call in to question whether there is a physiological role for MGF.


1987 ◽  
Vol 105 (2) ◽  
pp. 965-975 ◽  
Author(s):  
L M Wakefield ◽  
D M Smith ◽  
T Masui ◽  
C C Harris ◽  
M B Sporn

Scatchard analyses of the binding of transforming growth factor-beta (TGF-beta) to a wide variety of different cell types in culture revealed the universal presence of high affinity (Kd = 1-60 pM) receptors for TGF-beta on every cell type assayed, indicating a wide potential target range for TGF-beta action. There was a strong (r = +0.85) inverse relationship between the receptor affinity and the number of receptors expressed per cell, such that at low TGF-beta concentrations, essentially all cells bound a similar number of TGF-beta molecules per cell. The binding of TGF-beta to various cell types was not altered by many agents that affect the cellular response to TGF-beta, suggesting that modulation of TGF-beta binding to its receptor may not be a primary control mechanism in TGF-beta action. Similarly, in vitro transformation resulted in only relatively small changes in the cellular binding of TGF-beta, and for those cell types that exhibited ligand-induced down-regulation of the receptor, down-regulation was not extensive. Thus the strong conservation of binding observed between cell types is also seen within a given cell type under a variety of conditions, and receptor expression appears to be essentially constitutive. Finally, the biologically inactive form of TGF-beta, which constitutes greater than 98% of autocrine TGF-beta secreted by all of the twelve different cell types assayed, was shown to be unable to bind to the receptor without prior activation in vitro. It is proposed that this may prevent premature interaction of autocrine ligand and receptor in the Golgi apparatus.


2002 ◽  
Vol 282 (4) ◽  
pp. C899-C906 ◽  
Author(s):  
N. T Mesires ◽  
M. E. Doumit

Age-related changes in satellite cell proliferation and differentiation during rapid growth of porcine skeletal muscle were examined. Satellite cells were isolated from hindlimb muscles of pigs at 1, 7, 14, and 21 wk of age (4 animals/age group). Satellite cells were separated from cellular debris by using Percoll gradient centrifugation and were adsorbed to glass coverslips for fluorescent immunostaining. Positive staining for neural cell adhesion molecule (NCAM) distinguished satellite cells from nonmyogenic cells. The proportion of NCAM-positive cells (satellite cells) in isolates decreased from 1 to 7 wk of age. Greater than 77% of NCAM-positive cells were proliferating cell nuclear antigen positive at all ages studied. Myogenin-positive satellite cells decreased from 30% at 1 wk to 14% at 7 wk of age and remained at constant levels thereafter. These data indicate that a high percentage of satellite cells remain proliferative during rapid postnatal muscle growth. The reduced proportion of myogenin-positive cells during growth may reflect a decrease in the proportion of differentiating satellite cells or accelerated incorporation of myogenin-positive cells into myofibers.


1989 ◽  
Vol 23 (4) ◽  
pp. 295-301 ◽  
Author(s):  
J. A. Turton ◽  
C. M. Hawkey ◽  
M. G. Hart ◽  
J. Gwynne ◽  
R. M. Hicks

As little comprehensive baseline data are available on age-related haematological changes in genetically-defined rat strains, the haematology of female F344 rats is described in animals sampled at 2, 4, 8, 20, 66 and 121 weeks of age. Values for Hb, RBC and PCV increased from 2 weeks of age to reach adult levels at 8 weeks, whereas MCV, MCH and reticulocyte counts were high initially but decreased to reach the adult range at 8 weeks. Between 66 and 121 weeks, reticulocyte counts were significantly increased and values for MCHC significantly decreased. Lymphocytes were the predominant white cell type in each age group. The absolute numbers of neutrophils and lymphocytes showed slight variations between 2 and 66 weeks and both cell types increased significantly between 66 and121 weeks. Platelet counts showed no overall age-related trends. Fibrinogen values increased from 2 weeks of age to reach the adult level at 8 weeks. One animal of the 14 sampled at 121 weeks showed changes in the blood, liver and spleen consistent with a diagnosis of lymphoid leukaemia.


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