Dataset Information

Atmospheric oxygen tension slows myoblast proliferation via mitochondrial activation.

ABSTRACT:

Background

Mitochondrial activity inhibits proliferation and is required for differentiation of myoblasts. Myoblast proliferation is also inhibited by the ~20% oxygen level used in standard tissue culture. We hypothesize that mitochondrial activity would be greater at hyperoxia (20% O(2)) relative to more physiological oxygen (5% O(2)).

Methodology/principal findings

Murine primary myoblasts from isolated myofibres and conditionally immortalized H-2K myoblasts were cultured at 5% and 20% oxygen. Proliferation, assayed by cell counts, EdU labeling, and CFSE dilution, was slower at 20% oxygen. Expression of MyoD in primary myoblasts was delayed at 20% oxygen, but myogenicity, as measured by fusion index, was slightly higher. FACS-based measurement of mitochondrial activity indicators and luminometric measurement of ATP levels revealed that mitochondria exhibited greater membrane potential and higher levels of Reactive Oxygen Species (ROS) at 20% oxygen with concomitant elevation of intracellular ATP. Mitochondrial mass was unaffected. Low concentrations of CCCP, a respiratory chain uncoupler, and Oligomycin A, an ATP synthase inhibitor, each increased the rate of myoblast proliferation. ROS were investigated as a potential mechanism of mitochondrial retrograde signaling, but scavenging of ROS levels by N-acetyl-cysteine (NAC) or ?-Phenyl-N-tert-butylnitrone (PBN) did not rescue the suppressed rate of cell division in hyperoxic conditions, suggesting other pathways. Primary myoblasts from older mice showed a slower proliferation than those from younger adult mice at 20% oxygen but no difference at 5% oxygen.

Conclusions/significance

These results implicate mitochondrial regulation as a mechanistic explanation for myoblast response to oxygen tension. The rescue of proliferation rate in myoblasts of aged mice by 5% oxygen suggests a major artefactual component to age-related decline of satellite cell proliferation in standard tissue culture at 20% oxygen. It lends weight to the idea that these age-related changes result at least in part from environmental factors rather than characteristics intrinsic to the satellite cell.

SUBMITTER: Duguez S

PROVIDER: S-EPMC3427224 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Publications

Atmospheric oxygen tension slows myoblast proliferation via mitochondrial activation.

Duguez Stephanie S Duddy William J WJ Gnocchi Viola V Bowe James J Dadgar Sherry S Partridge Terence A TA

PloS one 20120824 8

<h4>Background</h4>Mitochondrial activity inhibits proliferation and is required for differentiation of myoblasts. Myoblast proliferation is also inhibited by the ~20% oxygen level used in standard tissue culture. We hypothesize that mitochondrial activity would be greater at hyperoxia (20% O(2)) relative to more physiological oxygen (5% O(2)).<h4>Methodology/principal findings</h4>Murine primary myoblasts from isolated myofibres and conditionally immortalized H-2K myoblasts were cultured at 5% ...[more]

PMID: 22937109

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Dataset Information

Atmospheric oxygen tension slows myoblast proliferation via mitochondrial activation.

Background

Methodology/principal findings

Conclusions/significance

Publications

Atmospheric oxygen tension slows myoblast proliferation via mitochondrial activation.

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