TY - JOUR
T1 - Enhanced Muscular Dystrophy from Loss of Dysferlin Is Accompanied by Impaired Annexin A6 Translocation after Sarcolemmal Disruption
AU - Demonbreun, Alexis R.
AU - Allen, Madison V.
AU - Warner, James L.
AU - Barefield, David Yeomans
AU - Krishnan, Swathi
AU - Swanson, Kaitlin E.
AU - Earley, Judy U.
AU - McNally, Elizabeth M.
N1 - Publisher Copyright:
© 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.
PY - 2016/6/1
Y1 - 2016/6/1
N2 - Dysferlin is a membrane-associated protein implicated in membrane resealing; loss of dysferlin leads to muscular dystrophy. We examined the same loss-of-function Dysf mutation in two different mouse strains, 129T2/SvEmsJ (Dysf129) and C57BL/6J (DysfB6). Although there are many genetic differences between these two strains, we focused on polymorphisms in Anxa6 because these variants were previously associated with modifying a pathologically distinct form of muscular dystrophy and increased the production of a truncated annexin A6 protein. Dysferlin deficiency in the C57BL/6J background was associated with increased Evan's Blue dye uptake into muscle and increased serum creatine kinase compared to the 129T2/SvEmsJ background. In the C57BL/6J background, dysferlin loss was associated with enhanced pathologic severity, characterized by decreased mean fiber cross-sectional area, increased internalized nuclei, and increased fibrosis, compared to that in Dysf129 mice. Macrophage infiltrate was also increased in DysfB6 muscle. High-resolution imaging of live myofibers demonstrated that fibers from DysfB6 mice displayed reduced translocation of full-length annexin A6 to the site of laser-induced sarcolemmal disruption compared to Dysf129 myofibers, and impaired translocation of annexin A6 associated with impaired resealing of the sarcolemma. These results provide one mechanism by which the C57BL/6J background intensifies dysferlinopathy, giving rise to a more severe form of muscular dystrophy in the DysfB6 mouse model through increased membrane leak and inflammation.
AB - Dysferlin is a membrane-associated protein implicated in membrane resealing; loss of dysferlin leads to muscular dystrophy. We examined the same loss-of-function Dysf mutation in two different mouse strains, 129T2/SvEmsJ (Dysf129) and C57BL/6J (DysfB6). Although there are many genetic differences between these two strains, we focused on polymorphisms in Anxa6 because these variants were previously associated with modifying a pathologically distinct form of muscular dystrophy and increased the production of a truncated annexin A6 protein. Dysferlin deficiency in the C57BL/6J background was associated with increased Evan's Blue dye uptake into muscle and increased serum creatine kinase compared to the 129T2/SvEmsJ background. In the C57BL/6J background, dysferlin loss was associated with enhanced pathologic severity, characterized by decreased mean fiber cross-sectional area, increased internalized nuclei, and increased fibrosis, compared to that in Dysf129 mice. Macrophage infiltrate was also increased in DysfB6 muscle. High-resolution imaging of live myofibers demonstrated that fibers from DysfB6 mice displayed reduced translocation of full-length annexin A6 to the site of laser-induced sarcolemmal disruption compared to Dysf129 myofibers, and impaired translocation of annexin A6 associated with impaired resealing of the sarcolemma. These results provide one mechanism by which the C57BL/6J background intensifies dysferlinopathy, giving rise to a more severe form of muscular dystrophy in the DysfB6 mouse model through increased membrane leak and inflammation.
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U2 - 10.1016/j.ajpath.2016.02.005
DO - 10.1016/j.ajpath.2016.02.005
M3 - Article
C2 - 27070822
AN - SCOPUS:84969888182
VL - 186
SP - 1610
EP - 1622
JO - American Journal of Pathology
JF - American Journal of Pathology
SN - 0002-9440
IS - 6
ER -