title: Post-Natal knockdown of fukutin-related protein expression in muscle by long-termRNA interference induces dystrophic pathology [corrected].
abstract: Limb-girdle muscular dystrophy 2I (LGMD2I) is caused by mutations in the fukutin-related protein (FKRP) gene. Unlike its severe allelic forms, LGMD2I usually involves slower onset and milder course without defects in the central nervous system. The lack of viable animal models that closely recapitulate LGMD2I clinical phenotypes led us to use RNA interference technology to knock down FKRP expression via postnatal gene delivery so as to circumvent embryonic lethality. Specifically, an adeno-associated viral vector was used to deliver short hairpin (shRNA) genes to healthy ICR mice. Adeno-associated viral vectors expressing a single shRNA or two different shRNAs were injected one time into the hind limb muscles. We showed that FKRP expression at 10 months postinjection was reduced by about 50% with a single shRNA and by 75% with the dual shRNA cassette. Dual-cassette injection also reduced a-dystroglycan glycosylation and its affinity to laminin by up to 70% and induced α-dystrophic pathology, including fibrosis and central nucleation, in more than 50% of the myofibers at 10 months after injection. These results suggest that the reduction of approximately or more than 75% of the normal level of FKRP expression induces chronic dystrophic phenotypes in skeletal muscles. Furthermore, the restoration of about 25% of the normal FKRP level could be sufficient for LGMD2I therapy to correct the genetic deficiency effectively and prevent dystrophic pathology.
authors.affiliation: Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors.forename: Chi-Hsien
authors.initials: CH
authors.lastname: Wang
authors.forename: Yiumo Michael
authors.initials: YM
authors.lastname: Chan
authors.forename: Ru-Hang
authors.initials: RH
authors.lastname: Tang
authors.forename: Bin
authors.initials: B
authors.lastname: Xiao
authors.forename: Peijuan
authors.initials: P
authors.lastname: Lu
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Keramaris-Vrantsis
authors.forename: Hui
authors.initials: H
authors.lastname: Zheng
authors.forename: Chunping
authors.initials: C
authors.lastname: Qiao
authors.forename: Jiangang
authors.initials: J
authors.lastname: Jiang
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Hsin-I
authors.initials: HI
authors.lastname: Ma
authors.forename: Qilong
authors.initials: Q
authors.lastname: Lu
authors.forename: Xiao
authors.initials: X
authors.lastname: Xiao
mesh_terms: D000256:Adenoviridae; D000818:Animals; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D049030:Dystroglycans / Q000378:metabolism; D055785:Gene Knockdown Techniques / Q000379:methods*; D005822:Genetic Vectors; D006031:Glycosylation; D051379:Mice; D008813:Mice, Inbred ICR; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology*; D049288:Muscular Dystrophies, Limb-Girdle / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D010430:Pentosyltransferases; D011506:Proteins / Q000235:genetics*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D014166:Transferases
chemical_list: D011506:Proteins; D034741:RNA, Small Interfering; D049030:Dystroglycans; D014166:Transferases; C499093:Fkrp protein, mouse; D010430:Pentosyltransferases