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Redox regulation of muscle adaptations to contractile activity and aging.

Jackson MJ - J. Appl. Physiol. (2015)

Bottom Line: Whether such changes in redox signaling reflect primary age-related changes or are secondary to the fundamental mechanisms is unclear.For instance, denervated muscle fibers within muscles from aged rodents or humans appear to generate large amounts of mitochondrial hydrogen peroxide that could influence adjacent innervated fibers.Thus, in this instance, a "secondary" source of reactive oxygen species may be potentially generated as a result of a primary age-related pathology (loss of neurons), but, nevertheless, may contribute to loss of muscle mass and function during aging.

View Article: PubMed Central - PubMed

Affiliation: MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom mjj@liverpool.ac.uk.

No MeSH data available.


Related in: MedlinePlus

Updated working scheme for sites of ROS/reactive nitrogen species (RNS) generation by skeletal muscle demonstrating the potential role of Nox2 and Nox4 isoforms of NADPH oxidase in generating superoxide in mitochondria and cytosol and acknowledging the lack of evidence for any release of superoxide from mitochondrial during contractile activity. NO, nitric oxide; ONOO−, peroxynitrite; ecSOD, extracellular SOD; eNOS, endothelial NO synthase; nNOS, neuronal NO synthase; PLA2, phospholipase A2; GPx, glutathione peroxidase; CAT, catalase; IMS, intermembrane space. [Modified from Jackson (33).]
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Figure 2: Updated working scheme for sites of ROS/reactive nitrogen species (RNS) generation by skeletal muscle demonstrating the potential role of Nox2 and Nox4 isoforms of NADPH oxidase in generating superoxide in mitochondria and cytosol and acknowledging the lack of evidence for any release of superoxide from mitochondrial during contractile activity. NO, nitric oxide; ONOO−, peroxynitrite; ecSOD, extracellular SOD; eNOS, endothelial NO synthase; nNOS, neuronal NO synthase; PLA2, phospholipase A2; GPx, glutathione peroxidase; CAT, catalase; IMS, intermembrane space. [Modified from Jackson (33).]

Mentions: A number of specific ROS and RNS are detected in the extracellular space of skeletal muscle myotubes or isolated fibers in culture or in microdialysates from muscle interstitial fluid in vivo. It appears that muscle fibers may have generating systems for superoxide that release this species into the extracellular space (53, 76). Substantial diffusion of superoxide (or its protonated form) through the plasma membrane seems extremely unlikely (27), but other species that are detected in the muscle extracellular space (e.g., hydrogen peroxide and NO) can potentially diffuse across membranes and hence may originate from intracellular sites. Javesghani et al. (41) reported that a plasma membrane-localized NAD(P)H oxidase could release superoxide to the external face of the membrane, and Ward et al. (96) have described a stretch-activated NADPH oxidase (Nox2 isoform) that plays a major role in contraction-induced ROS generation in cardiac myocytes. This enzyme is also reported to be present in the skeletal muscle plasma membrane and appears to release superoxide to the outside of the cell. Other NAD(P)H-dependent systems have also been suggested to play a role in release of superoxide from muscle fibers (34). In muscle in vivo or intact muscle preparations ex vivo, xanthine oxidase enzymes in the endothelium may also play an important role in contraction-induced release of superoxide (24), and this enzyme has been claimed to be important in adaptations of muscle to contractile activity (22). Figure 2 summarizes our present understanding of the sites that have been identified for generation of ROS and NO in skeletal muscle fibers.


Redox regulation of muscle adaptations to contractile activity and aging.

Jackson MJ - J. Appl. Physiol. (2015)

Updated working scheme for sites of ROS/reactive nitrogen species (RNS) generation by skeletal muscle demonstrating the potential role of Nox2 and Nox4 isoforms of NADPH oxidase in generating superoxide in mitochondria and cytosol and acknowledging the lack of evidence for any release of superoxide from mitochondrial during contractile activity. NO, nitric oxide; ONOO−, peroxynitrite; ecSOD, extracellular SOD; eNOS, endothelial NO synthase; nNOS, neuronal NO synthase; PLA2, phospholipase A2; GPx, glutathione peroxidase; CAT, catalase; IMS, intermembrane space. [Modified from Jackson (33).]
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526708&req=5

Figure 2: Updated working scheme for sites of ROS/reactive nitrogen species (RNS) generation by skeletal muscle demonstrating the potential role of Nox2 and Nox4 isoforms of NADPH oxidase in generating superoxide in mitochondria and cytosol and acknowledging the lack of evidence for any release of superoxide from mitochondrial during contractile activity. NO, nitric oxide; ONOO−, peroxynitrite; ecSOD, extracellular SOD; eNOS, endothelial NO synthase; nNOS, neuronal NO synthase; PLA2, phospholipase A2; GPx, glutathione peroxidase; CAT, catalase; IMS, intermembrane space. [Modified from Jackson (33).]
Mentions: A number of specific ROS and RNS are detected in the extracellular space of skeletal muscle myotubes or isolated fibers in culture or in microdialysates from muscle interstitial fluid in vivo. It appears that muscle fibers may have generating systems for superoxide that release this species into the extracellular space (53, 76). Substantial diffusion of superoxide (or its protonated form) through the plasma membrane seems extremely unlikely (27), but other species that are detected in the muscle extracellular space (e.g., hydrogen peroxide and NO) can potentially diffuse across membranes and hence may originate from intracellular sites. Javesghani et al. (41) reported that a plasma membrane-localized NAD(P)H oxidase could release superoxide to the external face of the membrane, and Ward et al. (96) have described a stretch-activated NADPH oxidase (Nox2 isoform) that plays a major role in contraction-induced ROS generation in cardiac myocytes. This enzyme is also reported to be present in the skeletal muscle plasma membrane and appears to release superoxide to the outside of the cell. Other NAD(P)H-dependent systems have also been suggested to play a role in release of superoxide from muscle fibers (34). In muscle in vivo or intact muscle preparations ex vivo, xanthine oxidase enzymes in the endothelium may also play an important role in contraction-induced release of superoxide (24), and this enzyme has been claimed to be important in adaptations of muscle to contractile activity (22). Figure 2 summarizes our present understanding of the sites that have been identified for generation of ROS and NO in skeletal muscle fibers.

Bottom Line: Whether such changes in redox signaling reflect primary age-related changes or are secondary to the fundamental mechanisms is unclear.For instance, denervated muscle fibers within muscles from aged rodents or humans appear to generate large amounts of mitochondrial hydrogen peroxide that could influence adjacent innervated fibers.Thus, in this instance, a "secondary" source of reactive oxygen species may be potentially generated as a result of a primary age-related pathology (loss of neurons), but, nevertheless, may contribute to loss of muscle mass and function during aging.

View Article: PubMed Central - PubMed

Affiliation: MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom mjj@liverpool.ac.uk.

No MeSH data available.


Related in: MedlinePlus