Effects of Transient Hypoxia versus Prolonged Hypoxia on Satellite Cell Proliferation and Differentiation In Vivo

The microenvironment of the injury site can have profound effects on wound healing. Muscle injury results in ischemia leading to short-term local hypoxia, but there are conflicting reports on the role of hypoxia on the myogenic program in vivo and in vitro. In our rat model of mitochondrial restoration (MR), temporary upregulation of mitochondrial activity by a cocktail of organelle-encoded RNAs results in satellite cell proliferation and initiation of myogenesis. We now report that MR leads to a transient hypoxic response in situ. Inhibition of hypoxia by lowering mitochondrial O2consumption, either by respiratory electron transport inhibitors, or by NO-mediated inhibition of O2binding to cytochrome c oxidase, resulted in exacerbation of inflammation. Lentivirus-mediated knockdown of hypoxia-inducible factor 1α(HIF1α) or of Notch signaling components had a similar effect, and pharmacologic inhibition of HIF or Notch reduced the number of proliferating Pax7+cells. In contrast, a prolonged hypoxic response induced either by uncoupling of respiration from oxidative phosphorylation or through HIF stabilization by dimethyloxalylglycine (DMOG) had an immediate anti-inflammatory effect. Although significant satellite cell proliferation occurred in presence of DMOG, expression of differentiation markers was affected. These results emphasize the importance of transient hypoxia as opposed to prolonged hypoxia for myogenesis.

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PEDF-derived peptide promotes skeletal muscle regeneration through its mitogenic effect on muscle progenitor cells

AJP Cell Physiology ◽

10.1152/ajpcell.00344.2014 ◽

2015 ◽

Vol 309 (3) ◽

pp. C159-C168 ◽

Cited By ~ 18

Author(s):

Tsung-Chuan Ho ◽

Yi-Pin Chiang ◽

Chih-Kuang Chuang ◽

Show-Li Chen ◽

Jui-Wen Hsieh ◽

...

Keyword(s):

Skeletal Muscle ◽

Cell Proliferation ◽

Cyclin D1 ◽

Satellite Cell ◽

Muscle Regeneration ◽

Muscle Fibers ◽

Skeletal Muscle Regeneration ◽

Satellite Cell Proliferation

In response injury, intrinsic repair mechanisms are activated in skeletal muscle to replace the damaged muscle fibers with new muscle fibers. The regeneration process starts with the proliferation of satellite cells to give rise to myoblasts, which subsequently differentiate terminally into myofibers. Here, we investigated the promotion effect of pigment epithelial-derived factor (PEDF) on muscle regeneration. We report that PEDF and a synthetic PEDF-derived short peptide (PSP; residues Ser93-Leu112) induce satellite cell proliferation in vitro and promote muscle regeneration in vivo. Extensively, soleus muscle necrosis was induced in rats by bupivacaine, and an injectable alginate gel was used to release the PSP in the injured muscle. PSP delivery was found to stimulate satellite cell proliferation in damaged muscle and enhance the growth of regenerating myofibers, with complete regeneration of normal muscle mass by 2 wk. In cell culture, PEDF/PSP stimulated C2C12 myoblast proliferation, together with a rise in cyclin D1 expression. PEDF induced the phosphorylation of ERK1/2, Akt, and STAT3 in C2C12 myoblasts. Blocking the activity of ERK, Akt, or STAT3 with pharmacological inhibitors attenuated the effects of PEDF/PSP on the induction of C2C12 cell proliferation and cyclin D1 expression. Moreover, 5-bromo-2′-deoxyuridine pulse-labeling demonstrated that PEDF/PSP stimulated primary rat satellite cell proliferation in myofibers in vitro. In summary, we report for the first time that PSP is capable of promoting the regeneration of skeletal muscle. The signaling mechanism involves the ERK, AKT, and STAT3 pathways. These results show the potential utility of this PEDF peptide for muscle regeneration.

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Exercise-enhanced satellite cell proliferation and new myonuclear accretion in rat skeletal muscle

Journal of Applied Physiology ◽

10.1152/jappl.2001.90.4.1407 ◽

2001 ◽

Vol 90 (4) ◽

pp. 1407-1414 ◽

Cited By ~ 59

Author(s):

Heather K. Smith ◽

Linda Maxwell ◽

Carol D. Rodgers ◽

Nancy H. McKee ◽

Michael J. Plyley

Keyword(s):

Skeletal Muscle ◽

Cell Proliferation ◽

Satellite Cell ◽

Normal Activity ◽

Adult Skeletal Muscle ◽

Vastus Intermedius ◽

Muscle Loading ◽

Satellite Cell Proliferation ◽

Exercise Induced

The effects of increased functional loading on early cellular regenerative events after exercise-induced injury in adult skeletal muscle were examined with the use of in vivo labeling of replicating myofiber nuclei and immunocyto- and histochemical techniques. Satellite cell proliferation in the soleus (Sol) of nonexercised rats (0.4 ± 0.2% of fibers) was unchanged after an initial bout of declined treadmill exercise but was elevated after two (1.0 ± 0.2%, P ≤ 0.01), but not four or seven, daily bouts of the same task. Myonuclei produced over the 7-day period comprised 0.9–1.9% of myonuclei in isolated fibers of Sol, tibialis anterior, and vastus intermedius of nonexercised rats. The accretion of new myonuclei was enhanced ( P ≤ 0.05) in Sol and vastus intermedius by the initial exercise followed by normal activity (to 3.1–3.4% of myonuclei) and more so by continued daily exercise (4.2–5.3%). Observed coincident with a lower incidence of histological fiber injury and unchanged fiber diameter and myonuclei per millimeter, the greater new myonuclear accretion induced by continued muscle loading may contribute to an enhanced fiber repair and regeneration after exercise-induced injury.

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Early-age heat exposure affects skeletal muscle satellite cell proliferation and differentiation in chicks

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.2001.281.1.r302 ◽

2001 ◽

Vol 281 (1) ◽

pp. R302-R309 ◽

Cited By ~ 66

Author(s):

Orna Halevy ◽

Alon Krispin ◽

Yael Leshem ◽

John P. McMurtry ◽

Shlomo Yahav

Keyword(s):

Cell Proliferation ◽

Growth Factor ◽

Satellite Cell ◽

Heat Exposure ◽

Muscle Growth ◽

Significant Difference ◽

Igf I ◽

Satellite Cell Proliferation ◽

Skeletal Muscle Satellite Cell

Exposure of young chicks to thermal conditioning (TC; i.e., 37°C for 24 h) resulted in significantly improved body and muscle growth at a later age. We hypothesized that TC causes an increase in satellite cell proliferation, necessary for further muscle hypertrophy. An immediate increase was observed in satellite cell DNA synthesis in culture and in vivo in response to TC of 3-day-old chicks to levels that were significantly higher than those of control chicks. This was accompanied by a marked induction of insulin-like growth factor-I (IFG-I), but not hepatocyte growth factor in the breast muscle. No significant difference between treatments in plasma IGF-I levels was observed. A marked elevation in muscle regulatory factors on day 5, followed by a decline in cell proliferation on day 6together with continuous high levels of IGF-I in the TC chick muscle may indicate accelerated cell differentiation. These data suggest a central role for IGF-I in the immediate stimulation of satellite cell myogenic processes in response to heat exposure.

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Importance of satellite cells in the strength recovery after eccentric contraction-induced muscle injury

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00032.2003 ◽

2003 ◽

Vol 285 (6) ◽

pp. R1490-R1495 ◽

Cited By ~ 42

Author(s):

Christopher R. Rathbone ◽

J. C. Wenke ◽

Gordon L. Warren ◽

R. B. Armstrong

Keyword(s):

Cell Proliferation ◽

Satellite Cell ◽

Muscle Injury ◽

Common Peroneal Nerve ◽

Eccentric Contraction ◽

Γ Irradiation ◽

Force Recovery ◽

Isometric Torque ◽

Satellite Cell Proliferation

The purpose of this study was to determine if the elimination of satellite cell proliferation using γ-irradiation would inhibit normal force recovery after eccentric contraction-induced muscle injury. Adult female ICR mice were implanted with a stimulating nerve cuff on the common peroneal nerve and assigned to one of four groups: 1) irradiation- and eccentric contraction-induced injury, 2) eccentric contraction-induced injury only, 3) irradiation only, and 4) no intervention. Anterior crural muscles were irradiated with a dose of 2,500 rad and injured with 150 in vivo maximal eccentric contractions. Maximal isometric torque was determined weekly through 35 days postinjury. Immediately after injury, maximal isometric torque was reduced by ∼50% and had returned to normal by 28 days postinjury in the nonirradiated injured mice. However, torque production of irradiated injured animals did not recover fully and was 25% less than that of injured nonirradiated mice 35 days postinjury. These data suggest that satellite cell proliferation is required for approximately half of the force recovery after eccentric contraction-induced injury.

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Low-energy laser irradiation affects satellite cell proliferation and differentiation in vitro

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research ◽

10.1016/s0167-4889(98)00147-5 ◽

1999 ◽

Vol 1448 (3) ◽

pp. 372-380 ◽

Cited By ~ 120

Author(s):

Nadav Ben-Dov ◽

Gavriella Shefer ◽

Andrey Irinitchev ◽

Anton Wernig ◽

Uri Oron ◽

...

Keyword(s):

Cell Proliferation ◽

Laser Irradiation ◽

Satellite Cell ◽

Low Energy ◽

Cell Proliferation And Differentiation ◽

Proliferation And Differentiation ◽

Energy Laser ◽

Satellite Cell Proliferation ◽

Low Energy Laser

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Satellite cell-mediated angiogenesis in vitro coincides with a functional hypoxia-inducible factor pathway

AJP Cell Physiology ◽

10.1152/ajpcell.00391.2008 ◽

2009 ◽

Vol 296 (6) ◽

pp. C1321-C1328 ◽

Cited By ~ 75

Author(s):

R. P. Rhoads ◽

R. M. Johnson ◽

C. R. Rathbone ◽

X. Liu ◽

C. Temm-Grove ◽

...

Keyword(s):

Gene Expression ◽

Satellite Cell ◽

Hypoxia Inducible Factor ◽

Collagen Gel ◽

Culture Conditions ◽

Cell Physiology ◽

Vegf Gene ◽

Protein Levels

Muscle regeneration involves the coordination of myogenesis and revascularization to restore proper muscle function. Myogenesis is driven by resident stem cells termed satellite cells (SC), whereas angiogenesis arises from endothelial cells and perivascular cells of preexisting vascular segments and the collateral vasculature. Communication between myogenic and angiogenic cells seems plausible, especially given the number of growth factors produced by SC. To characterize these interactions, we developed an in vitro coculture model composed of rat skeletal muscle SC and microvascular fragments (MVF). In this system, isolated epididymal MVF suspended in collagen gel are cultured over a rat SC monolayer culture. In the presence of SC, MVF exhibit greater indices of angiogenesis than MVF cultured alone. A positive dose-dependent effect of SC conditioned medium (CM) on MVF growth was observed, suggesting that SC secrete soluble-acting growth factor(s). Next, we specifically blocked VEGF action in SC CM, and this was sufficient to abolish satellite cell-induced angiogenesis. Finally, hypoxia-inducible factor-1α (HIF-1α), a transcriptional regulator of VEGF gene expression, was found to be expressed in cultured SC and in putative SC in sections of in vivo stretch-injured rat muscle. Hypoxic culture conditions increased SC HIF-1α activity, which was positively associated with SC VEGF gene expression and protein levels. Collectively, these initial observations suggest that a heretofore unexplored aspect of satellite cell physiology is the initiation of a proangiogenic program.

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