Smooth muscle-specific dystrophin expression improves aberrant vasoregulation in mdx mice.
Duchenne muscular dystrophy (DMD) is a fatal X-linked muscle-wasting disease caused by mutations of the gene encoding the cytoskeletal protein dystrophin. Therapeutic options for DMD are limited because the pathogenetic mechanism by which dystrophin deficiency produces the clinical phenotype remains obscure. Recent reports of abnormal alpha-adrenergic vasoregulation in the exercising muscles of DMD patients and in the mdx mouse, an animal model of DMD, prompted us to hypothesize that the dystrophin-deficient smooth muscle contributes to the vascular and dystrophic phenotypes of DMD. To test this, we generated transgenic mdx mice that express dystrophin only in smooth muscle (SMTg/mdx). We found that alpha-adrenergic vasoconstriction was markedly attenuated in the contracting hindlimbs of C57BL/10 wild-type mice, an effect that was mediated by nitric oxide (NO) and was severely impaired in the mdx mice. SMTg/mdx mice showed an intermediate phenotype, with partial restoration of the NO-dependent modulation of alpha-adrenergic vasoconstriction in active muscle. In addition, the elevated serum creatine kinase levels observed in mdx mice were significantly reduced in SMTg/mdx mice. This is the first report of a functional role of dystrophin in vascular smooth muscle.
Ito
Kaori
K
Department of Child Development, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University Graduate School, Kumamoto 860-0811, Japan.
Kimura
Shigemi
S
Ozasa
Shiro
S
Matsukura
Makoto
M
Ikezawa
Makoto
M
Yoshioka
Kowashi
K
Ueno
Hiroe
H
Suzuki
Misao
M
Araki
Kimi
K
Yamamura
Ken-ichi
K
Miwa
Takeshi
T
Dickson
George
G
Thomas
Gail D
GD
Miike
Teruhisa
T
D000818:Animals; D001483:Base Sequence; D003402:Creatine Kinase / Q000097:blood; D018076:DNA, Complementary / Q000235:genetics; D016189:Dystrophin / Q000235:genetics* / Q000502:physiology*; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018101:Mice, Inbred mdx; D008822:Mice, Transgenic; D009119:Muscle Contraction; D009131:Muscle, Smooth, Vascular / Q000098:blood supply / Q000503:physiopathology*; D009137:Muscular Dystrophy, Animal / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology*; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics / Q000503:physiopathology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011942:Receptors, Adrenergic, alpha / Q000502:physiology; D014661:Vasoconstriction
D018076:DNA, Complementary; D016189:Dystrophin; D011942:Receptors, Adrenergic, alpha; D019001:Nitric Oxide Synthase; D003402:Creatine Kinase