Universität zu Köln

Oexner, Rafael R., Pla-Martin, David, Pass, Thomas, Wiesen, Martin H. J., Zentis, Peter, Schauss, Astrid, Baris, Olivier R., Kimoloi, Sammy and Wiesner, Rudolf J. (2020). Extraocular Muscle Reveals Selective Vulnerability of Type IIB Fibers to Respiratory Chain Defects Induced by Mitochondrial DNA Alterations. Invest. Ophthalmol. Vis. Sci., 61 (12). ROCKVILLE: ASSOC RESEARCH VISION OPHTHALMOLOGY INC. ISSN 1552-5783

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Abstract

PURPOSE. The purpose of this study was to gain insights on the pathogenesis of chronic progressive external ophthalmoplegia, thus we investigated the vulnerability of five extra ocular muscles (EOMs) fiber types to pathogenic mitochondrial DNA deletions in a mouse model expressing a mutated mitochondrial helicase TWINKLE. METHODS. Consecutive pairs of EOM sections were analyzed by cytochrome C oxidase (COX)/succinate dehydrogenase (SDH) assay and fiber type specific immunohistochemistry (type I, IIA, IIB, embryonic, and EOM-specific staining). RESULTS. The mean average of COX deficient fibers (COX-) in the recti muscles of mutant mice was 1.04 +/- 0.52% at 12 months and increased with age (7.01 +/- 1.53% at 24 months). A significant proportion of these COX-fibers were of the fast-twitch, glycolytic type IIB (> 50% and > 35% total COX-fibers at 12 and 24 months, respectively), whereas embryonic myosin heavy chain-expressing fibers were almost completely spared. Furthermore, the proportion of COX-fibers in the type IIB-rich retractor bulbi muscle was > 2-fold higher compared to the M. recti at both 12 (2.6 +/- 0.78%) and 24 months (20.85 +/- 2.69%). Collectively, these results demonstrate a selective vulnerability of type IIB fibers to mitochondrial DNA (mtDNA) deletions in EOMs and retractor bulbi muscle. We also show that EOMs of mutant mice display histopathological abnormalities, including altered fiber type composition, increased fibrosis, ragged red fibers, and infiltration of mononucleated nonmuscle cells. CONCLUSIONS. Our results point to the existence of fiber type IIB-intrinsic factors and/or molecular mechanisms that predispose them to increased generation, clonal expansion, and detrimental effects of mtDNA deletions.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Oexner, Rafael R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Pla-Martin, David UNSPECIFIED UNSPECIFIED UNSPECIFIED Pass, Thomas UNSPECIFIED UNSPECIFIED UNSPECIFIED Wiesen, Martin H. J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Zentis, Peter UNSPECIFIED UNSPECIFIED UNSPECIFIED Schauss, Astrid UNSPECIFIED UNSPECIFIED UNSPECIFIED Baris, Olivier R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kimoloi, Sammy UNSPECIFIED UNSPECIFIED UNSPECIFIED Wiesner, Rudolf J. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-316042
DOI:	10.1167/iovs.61.12.14
Journal or Publication Title:	Invest. Ophthalmol. Vis. Sci.
Volume:	61
Number:	12
Date:	2020
Publisher:	ASSOC RESEARCH VISION OPHTHALMOLOGY INC
Place of Publication:	ROCKVILLE
ISSN:	1552-5783
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language PROGRESSIVE EXTERNAL OPHTHALMOPLEGIA; LAYER-SPECIFIC DIFFERENCES; SKELETAL-MUSCLE; DELETION MUTATIONS; ABNORMALITIES; EXPRESSION; CELLS Multiple languages Ophthalmology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/31604