Résumé :
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Duchenne muscular dystrophy is due to the absence of dystrophin, a cytoskeletal protein associated with plasma membrane of skeletal muscle cells. This causes a severe muscle degeneration. In normal cells, dystrophin is associated, via its carboxy-terminal end, with a complex of proteins and glycoproteins anchored in the plasma membrane, and via its amino-terminal end, with actin filaments of the cytoskeleton. The absence of dystrophin induces a rupture of the mechanical link between the cytoskeleton and the extracellular matrix. This makes the membrane apparently more fragile and dystrophic muscle is thus particularly sensitive to the lengthening (eccentric) contractions. The absence of dystrophin also causes an abnormal control of certain membrane ion channels resulting in an exaggerated entry of calcium that could activate calcium-dependent proteases (calpains) and induce a dysfunction of mitochondria. We recently identified two ion channels that seem to play an important role in muscle function and in the pathophysiology of the disease, TRPC1 and TRPV2, two members of the Transient Receptor Potential channels family. TRPC1 controls the speed of migration of myoblasts and their differentiation in myotubes. It is therefore important in muscle regeneration. TRPV2 is activated by membrane stretch and its inhibition or its repression seems to protect muscle against the damage caused by eccentric exercises. Besides, other TRP channels are possibly involved in muscle development, Ca2+ homeostasis.
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