Role of Inflammation in Muscle Homeostasis and Myogenesis.
Skeletal muscle mass is subject to rapid changes according to growth stimuli inducing both hypertrophy, through increased protein synthesis, and hyperplasia, activating the myogenic program. Muscle wasting, characteristic of several pathological states associated with local or systemic inflammation, has been for long considered to rely on the alteration of myofiber intracellular pathways regulated by both hormones and cytokines, eventually leading to impaired anabolism and increased protein breakdown. However, there are increasing evidences that even alterations of the myogenic/regenerative program play a role in the onset of muscle wasting, even though the precise mechanisms involved are far from being fully elucidated. The comprehension of the links potentially occurring between impaired myogenesis and increased catabolism would allow the definition of effective strategies aimed at counteracting muscle wasting. The first part of this review gives an overview of skeletal muscle intracellular pathways determining fiber size, while the second part considers the cells and the regulatory pathways involved in the myogenic program. In both parts are discussed the evidences supporting the role of inflammation in impairing muscle homeostasis and myogenesis, potentially determining muscle atrophy.
Department of Clinical and Biological Sciences, University of Torino, 10125 Torino, Italy ; Stem Cell Research Institute, University Hospital Gasthuisberg, 3000 Leuven, Belgium ; Interuniversity Institute of Myology (IIM), Italy.
Domiziana
D
Costamagna
Department of Clinical and Biological Sciences, University of Torino, 10125 Torino, Italy ; Interuniversity Institute of Myology (IIM), Italy.
Paola
P
Costelli
Stem Cell Research Institute, University Hospital Gasthuisberg, 3000 Leuven, Belgium ; Interuniversity Institute of Myology (IIM), Italy ; Human Anatomy Section, University of Pavia, 27100 Pavia, Italy.
Maurilio
M
Sampaolesi
Department of Clinical and Biological Sciences, University of Torino, 10125 Torino, Italy ; Interuniversity Institute of Myology (IIM), Italy.
Fabio
F
Penna
D000818:Animals; D001343:Autophagy; D002454:Cell Differentiation; D016207:Cytokines / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D006984:Hypertrophy / Q000473:pathology; D007249:Inflammation / Q000378:metabolism*; D024510:Muscle Development; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D009133:Muscular Atrophy / Q000473:pathology; D012038:Regeneration; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology
D016207:Cytokines