Tectorial Membrane Material Properties in Tecta[superscript Y1870C+] Heterozygous Mice
The solid component of the tectorial membrane (TM) is a porous matrix made up of the radial collagen fibers and the striated sheet matrix. The striated sheet matrix is believed to contribute to shear impedance in both the radial and longitudinal directions, but the molecular mechanisms involved have...
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| Format: | Article |
| Language: | en_US |
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Elsevier
2015
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| Online Access: | http://hdl.handle.net/1721.1/96042 https://orcid.org/0000-0001-6309-0910 https://orcid.org/0000-0003-3369-5067 |
| _version_ | 1811081041330307072 |
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| author | Masaki, Kinuko Ghaffari, Roozbeh Gu, Jianwen Wendy Richardson, Guy P. Freeman, Dennis M. Aranyosi, Alexander J. |
| author2 | Harvard University--MIT Division of Health Sciences and Technology |
| author_facet | Harvard University--MIT Division of Health Sciences and Technology Masaki, Kinuko Ghaffari, Roozbeh Gu, Jianwen Wendy Richardson, Guy P. Freeman, Dennis M. Aranyosi, Alexander J. |
| author_sort | Masaki, Kinuko |
| collection | MIT |
| description | The solid component of the tectorial membrane (TM) is a porous matrix made up of the radial collagen fibers and the striated sheet matrix. The striated sheet matrix is believed to contribute to shear impedance in both the radial and longitudinal directions, but the molecular mechanisms involved have not been determined. A missense mutation in Tecta, a gene that encodes for the α-tectorin protein in the striated sheet matrix, causes a 60-dB threshold shift in mice with relatively little reduction in outer hair cell amplification. Here, we show that this threshold shift is coupled to changes in shear impedance, response to osmotic pressure, and concentration of fixed charge of the TM. In Tecta[superscript Y1870C+] mice, the tectorin content of the TM was reduced, as was the content of glycoconjugates reacting with the lectin wheat germ agglutinin. Charge measurements showed a decrease in fixed charge concentration from −6.4±1.4−6.4±1.4 mmol/L in wild-types to −2.1±0.7−2.1±0.7 mmol/L in Tecta[superscript Y1870C+] TMs. TMs from Tecta[superscript Y1870C+] mice showed little volume change in response to osmotic pressure compared to those of wild-type mice. The magnitude of both radial and longitudinal TM shear impedance was reduced by 10±1.610±1.6 dB in Tecta[superscript Y1870C+] mice. However, the phase of shear impedance was unchanged. These changes are consistent with an increase in the porosity of the TM and a corresponding decrease of the solid fraction. Mechanisms by which these changes can affect the coupling between outer and inner hair cells are discussed. |
| first_indexed | 2024-09-23T11:40:48Z |
| format | Article |
| id | mit-1721.1/96042 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T11:40:48Z |
| publishDate | 2015 |
| publisher | Elsevier |
| record_format | dspace |
| spelling | mit-1721.1/960422022-09-27T21:10:16Z Tectorial Membrane Material Properties in Tecta[superscript Y1870C+] Heterozygous Mice Masaki, Kinuko Ghaffari, Roozbeh Gu, Jianwen Wendy Richardson, Guy P. Freeman, Dennis M. Aranyosi, Alexander J. Harvard University--MIT Division of Health Sciences and Technology Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology. Research Laboratory of Electronics Ghaffari, Roozbeh Masaki, Kinuko Gu, Jianwen Wendy Freeman, Dennis M. Aranyosi, Alexander J. The solid component of the tectorial membrane (TM) is a porous matrix made up of the radial collagen fibers and the striated sheet matrix. The striated sheet matrix is believed to contribute to shear impedance in both the radial and longitudinal directions, but the molecular mechanisms involved have not been determined. A missense mutation in Tecta, a gene that encodes for the α-tectorin protein in the striated sheet matrix, causes a 60-dB threshold shift in mice with relatively little reduction in outer hair cell amplification. Here, we show that this threshold shift is coupled to changes in shear impedance, response to osmotic pressure, and concentration of fixed charge of the TM. In Tecta[superscript Y1870C+] mice, the tectorin content of the TM was reduced, as was the content of glycoconjugates reacting with the lectin wheat germ agglutinin. Charge measurements showed a decrease in fixed charge concentration from −6.4±1.4−6.4±1.4 mmol/L in wild-types to −2.1±0.7−2.1±0.7 mmol/L in Tecta[superscript Y1870C+] TMs. TMs from Tecta[superscript Y1870C+] mice showed little volume change in response to osmotic pressure compared to those of wild-type mice. The magnitude of both radial and longitudinal TM shear impedance was reduced by 10±1.610±1.6 dB in Tecta[superscript Y1870C+] mice. However, the phase of shear impedance was unchanged. These changes are consistent with an increase in the porosity of the TM and a corresponding decrease of the solid fraction. Mechanisms by which these changes can affect the coupling between outer and inner hair cells are discussed. National Institutes of Health (U.S.) (Grant R01-DC00238) National Institutes of Health (U.S.) (Training Grant) Wellcome Trust (London, England) National Institutes of Health (U.S.) (Grant R01-DC03544) 2015-03-17T15:49:15Z 2015-03-17T15:49:15Z 2010-11 2010-05 Article http://purl.org/eprint/type/JournalArticle 00063495 1542-0086 http://hdl.handle.net/1721.1/96042 Masaki, Kinuko, Roozbeh Ghaffari, Jianwen Wendy Gu, Guy P. Richardson, Dennis M. Freeman, and A.J. Aranyosi. “Tectorial Membrane Material Properties in Tecta[superscript Y1870C+] Heterozygous Mice.” Biophysical Journal 99, no. 10 (November 2010): 3274–3281. © 2010 Biophysical Society https://orcid.org/0000-0001-6309-0910 https://orcid.org/0000-0003-3369-5067 en_US http://dx.doi.org/10.1016/j.bpj.2010.09.033 Biophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Elsevier Elsevier |
| spellingShingle | Masaki, Kinuko Ghaffari, Roozbeh Gu, Jianwen Wendy Richardson, Guy P. Freeman, Dennis M. Aranyosi, Alexander J. Tectorial Membrane Material Properties in Tecta[superscript Y1870C+] Heterozygous Mice |
| title | Tectorial Membrane Material Properties in Tecta[superscript Y1870C+] Heterozygous Mice |
| title_full | Tectorial Membrane Material Properties in Tecta[superscript Y1870C+] Heterozygous Mice |
| title_fullStr | Tectorial Membrane Material Properties in Tecta[superscript Y1870C+] Heterozygous Mice |
| title_full_unstemmed | Tectorial Membrane Material Properties in Tecta[superscript Y1870C+] Heterozygous Mice |
| title_short | Tectorial Membrane Material Properties in Tecta[superscript Y1870C+] Heterozygous Mice |
| title_sort | tectorial membrane material properties in tecta superscript y1870c heterozygous mice |
| url | http://hdl.handle.net/1721.1/96042 https://orcid.org/0000-0001-6309-0910 https://orcid.org/0000-0003-3369-5067 |
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