Perimysial fibroblasts of extraocular muscle are as unique as the muscle fibers
Linda Louise Kusner 1*,
Andrew B Young 2,
Steven Tjoe 3,
Patrick Leahy 4,
and
Henry J Kaminski 5
1 Ophthalmology, Saint Louis University, 1438 South Grand Ave, Saint Louis, Missouri, 63104, United States
2 Dermatology, Case Western Reserve University, Cleveland, Ohio, United States
3 Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States
4 Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio, United States
5 Neurology and Psychiatry, Saint Louis University, Saint Louis, Missouri, United States
* To whom correspondence should be addressed. E-mail: lkusner{at}slu.edu.
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Abstract |
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Purpose: Extraocular muscle (EOM) has a distinct skeletal muscle phenotype. We hypothesize that fibroblasts support the unique EOM phenotype and that perimysial fibroblasts derived from EOM have properties that distinguish them from fibroblasts derived from other skeletal muscle.
Methods: Perimysial fibroblasts from leg muscle (LM-Fibro) and EOM (EOM-Fibro) of mice were derived and maintained in culture. EOM-Fibro and LM-Fibro were assessed morphologically and for vimentin, smooth muscle actin, and Thy-1 immunoreactivity. DNA microarray analysis was performed on LM-Fibro and EOM-Fibro grown in conditions that support myoblast differentiation. To assess trophic interactions, co-cultures of myoblasts from established cell lines, CL-EOM and CL-LM with, EOM-Fibro or LM-Fibro were performed in direct contact and in a transwell system. The degree of myotube maturation was assessed by the percentage of myotubes with more than three myonuclei per myotube.
Results: EOM-Fibro and LM-Fibro cells exhibited distinct morphologies. Both cell types proliferated as a monolayer and expressed vimentin. Fifty-five percent (sd 4.4%) of EOM-Fibro were Thy-1 positive compared with only 24% (sd 4.4%) of LM-Fibro. DNA microarray analysis demonstrated differential expression of structural, immune response, and metabolism related genes between EOM-Fibro and LM-Fibro. Co-cultures demonstrated that mature myotube formation in EOM-derived cell lines was supported to a greater extent by EOM-Fibro than by LM-Fibro, compared to CL-EOM grown with LM-Fibro.
Conclusion: Fibroblasts from extraocular muscle demonstrate distinct properties that distinguish them from leg muscle-derived fibroblasts. The distinct properties of EOM-Fibro may support the unique extraocular muscle phenotype and contribute to their differential involvement in to disease.
Key Words:
cell culture, extracellular matrix, extraocular muscle, Graves- disease
