Glial dystrophin-associated proteins, laminin and agrin, are downregulated in the brain of mdx mouse.
In this study, we investigated the involvement of dystrophin-associated proteins (DAPs) and their relationship with the perivascular basement membrane in the brains of mdx mice and controls at the age of 2 months. We analyzed (1) the expression of glial DAPs α-β-dystroglycan (DG), α-syntrophin, aquaporin-4 (AQP4) water channel, Kir 4.1 and dystrophin isoform (Dp71) by immunocytochemistry, laser confocal microscopy, immunogold electron microscopy, immunoblotting and RT-PCR; (2) the ultrastructure of the basement membrane and expression of laminin and agrin; and (3) the dual immunofluorescence colocalization of AQP4/α-β-DG, and of Kir 4.1/agrin. The following results were observed in mdx brain as compared with controls: (1) a significant reduction in protein content and mRNA expression of DAPs; (2) ultrastructurally, a thickened and discontinuous appearance of the basement membrane and a significant reduction in laminin and agrin; and (3) a molecular rearrangment of α-β-DG, coupled with a parallel loss of agrin and Kir 4.1 on basement membrane and glial endfeet. These data indicate that in mdx brain the deficiency in dystrophin and dystrophin isoform (Dp71) is coupled with a reduction of DAP components, coupled with an altered anchoring to the basement membrane.
Nico
Beatrice
B
Department of Human Anatomy and Histology, University of Bari Medical School, Bari, Italy. nico@histology.uniba.it
Tamma
Roberto
R
Annese
Tiziana
T
Mangieri
Domenica
D
De Luca
Annamaria
A
Corsi
Patrizia
P
Benagiano
Vincenzo
V
Longo
Vito
V
Crivellato
Enrico
E
Salmaggi
Andrea
A
Ribatti
Domenico
D
D018171:Agrin / Q000032:analysis*; D000818:Animals; D051401:Aquaporin 4 / Q000032:analysis; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000032:analysis; D004195:Disease Models, Animal; D015536:Down-Regulation; D049030:Dystroglycans / Q000032:analysis; D049029:Dystrophin-Associated Proteins / Q000032:analysis*; D005455:Fluorescent Antibody Technique; D007797:Laminin / Q000032:analysis*; D008565:Membrane Proteins / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D018101:Mice, Inbred mdx; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D009124:Muscle Proteins / Q000032:analysis; D020388:Muscular Dystrophy, Duchenne / Q000378:metabolism* / Q000473:pathology; D024661:Potassium Channels, Inwardly Rectifying / Q000032:analysis; D000098854:Kcnj10 Channel
D018171:Agrin; C496031:Aqp4 protein, mouse; D051401:Aquaporin 4; D002135:Calcium-Binding Proteins; D049029:Dystrophin-Associated Proteins; D000098854:Kcnj10 Channel; D007797:Laminin; D008565:Membrane Proteins; D009124:Muscle Proteins; D024661:Potassium Channels, Inwardly Rectifying; C091825:syntrophin alpha1; D049030:Dystroglycans