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- Title
Emerging Role of Nonmuscle Myosin II and Implications for NMMII Associated Deafness.
- Authors
Kozin, Elliott; Kachar, Bechara; Salles, Felipe; Adelstein, Robert; Ma, Xuefei; Zhang, Yingfan; Andrade, Leonardo R.
- Abstract
Objective: Data are scarce regarding the role of nonmuscle myosin II (NMMII) isoforms in the postnatal inner ear. Here we seek to: 1) understand the localization and function of each isoform in the postnatal environment, and 2) investigate the cause of hearing loss observed in mutations of NMMII. Method: Organ of Corti tissue was dissected from neonatal eGFP‐NMMII‐A or ‐B mice, and immunohistochemistry was performed using NMMII‐isoform specific antibodies. OC cultures of rat were exposed to NMMII inhibitors at multiple time points. NMMII‐C KO mice were stained with NMMII‐isoform specific antibodies. ABRs on NMMII‐A mutants were performed at various frequencies. Results: In WT mice, NMMII isoforms localize to the apical junction between hair and supporting cells. In eGFP‐NMMII‐A‐ or ‐B mice, NMMII isoform antibodies show a similar pattern of distribution, but are potentially expressed at different amounts. At the adhesion belt, the isoforms take on a "sarcomeric‐like" pattern. NMMII inhibition results in variability of hair cell shape. In NMMII‐C KO mice, NMMII‐A demonstrates a new distribution and NMMII‐B is upregulated. ABRs reveal an absence of hearing loss in NMMII‐A D1424N and R702C mutant mice compared to controls. Conclusion: NMMII has a previously unrecognized "sarcomeric‐like" pattern of organization, compatible with a contractile structure. Absence of hearing loss in NMMII‐A mutants indicates that hearing loss may require a secondary insult, and isoforms have potential for compensation and overlap in function, which may also mitigate hearing loss.
- Subjects
NONMUSCLE myosin; DEAFNESS; CORTI'S organ
- Publication
Otolaryngology-Head & Neck Surgery, 2011, Vol 145, pP209
- ISSN
0194-5998
- Publication type
Abstract
- DOI
10.1177/0194599811415823a246