Tgfbr2 is required in Acan‐expressing cells for maintenance of the intervertebral and sternocostal joints
Background Members of the transforming growth factor beta (TGF‐β) family are secreted proteins that regulate skeletal development. TGF‐β signaling is critical in embryonic development of the annulus fibrosus (AF) of the intervertebral disc (IVD). To address the question of the role of TGF‐β signalin...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Wiley
2018-06-01
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| Series: | JOR Spine |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/jsp2.1025 |
| _version_ | 1818839607609917440 |
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| author | Bashar Alkhatib Cunren Liu Rosa Serra |
| author_facet | Bashar Alkhatib Cunren Liu Rosa Serra |
| author_sort | Bashar Alkhatib |
| collection | DOAJ |
| description | Background Members of the transforming growth factor beta (TGF‐β) family are secreted proteins that regulate skeletal development. TGF‐β signaling is critical in embryonic development of the annulus fibrosus (AF) of the intervertebral disc (IVD). To address the question of the role of TGF‐β signaling in postnatal development and maintenance of the skeleton, we generated mice in which Tgfbr2 was deleted at 2‐weeks of age in Aggrecan (Acan)‐expressing cells using inducible Cre/LoxP recombination. Methods Localization of Cre recombination was visualized by crossing Acantm1(cre/ERT2)Crm mice to fluorescent mTmG reporter mice. Acantm1(cre/ERT2)Crm mice were mated to Tgfbr2LoxP/LoxP mice and Cre recombinase was activated by tamoxifen injection at 2‐weeks postnatally. Following tamoxifen injection, mice were aged to 3, 6, and 12‐months and control mice were compared to the experimental (cKO) group. Mice were initially analyzed using X‐ray and skeletal preparations. Sternocostal joints and IVD tissues were further analyzed histologically by hematoxylin and eosin (H&E), Safranin O, and Picrosirius Red staining as well as Col10 immunostaining. Results Cre recombination was observed in the IVD and sternocostal joints. X‐ray analysis revealed osteophyte formation within the disc space of 12‐month‐old cKO mice. Skeletal preparations confirmed calcification within the IVD and the sternocostal joints in cKO mice. H&E staining of cKO IVD revealed disorganized growth plates, delay in the formation of the bony endplate, and Col10 staining in the AF indicative of ectopic endochondral bone formation. Furthermore, proteoglycan loss was observed and collagen bundles within the inner AF were thinner and less organized. Alterations in the IVD were apparent beginning at 3 months and were progressively more visible at 6 and 12 months. Similarly, histological analysis of cKO sternocostal joints revealed joint calcification, proteoglycan loss, and disorganization of the collagen architecture at 12 months of age. Conclusions TGF‐β signaling is important for postnatal development and maintenance of fibrocartilaginous IVD and sternocostal joints. |
| first_indexed | 2024-12-19T03:56:59Z |
| format | Article |
| id | doaj.art-e0b04066e5a2491a992c2a38a873daaa |
| institution | Directory Open Access Journal |
| issn | 2572-1143 |
| language | English |
| last_indexed | 2024-12-19T03:56:59Z |
| publishDate | 2018-06-01 |
| publisher | Wiley |
| record_format | Article |
| series | JOR Spine |
| spelling | doaj.art-e0b04066e5a2491a992c2a38a873daaa2022-12-21T20:36:48ZengWileyJOR Spine2572-11432018-06-0112n/an/a10.1002/jsp2.1025Tgfbr2 is required in Acan‐expressing cells for maintenance of the intervertebral and sternocostal jointsBashar Alkhatib0Cunren Liu1Rosa Serra2Department of Cell, Developmental and Integrative Biology University of Alabama at Birmingham Birmingham AlabamaDepartment of Cell, Developmental and Integrative Biology University of Alabama at Birmingham Birmingham AlabamaDepartment of Cell, Developmental and Integrative Biology University of Alabama at Birmingham Birmingham AlabamaBackground Members of the transforming growth factor beta (TGF‐β) family are secreted proteins that regulate skeletal development. TGF‐β signaling is critical in embryonic development of the annulus fibrosus (AF) of the intervertebral disc (IVD). To address the question of the role of TGF‐β signaling in postnatal development and maintenance of the skeleton, we generated mice in which Tgfbr2 was deleted at 2‐weeks of age in Aggrecan (Acan)‐expressing cells using inducible Cre/LoxP recombination. Methods Localization of Cre recombination was visualized by crossing Acantm1(cre/ERT2)Crm mice to fluorescent mTmG reporter mice. Acantm1(cre/ERT2)Crm mice were mated to Tgfbr2LoxP/LoxP mice and Cre recombinase was activated by tamoxifen injection at 2‐weeks postnatally. Following tamoxifen injection, mice were aged to 3, 6, and 12‐months and control mice were compared to the experimental (cKO) group. Mice were initially analyzed using X‐ray and skeletal preparations. Sternocostal joints and IVD tissues were further analyzed histologically by hematoxylin and eosin (H&E), Safranin O, and Picrosirius Red staining as well as Col10 immunostaining. Results Cre recombination was observed in the IVD and sternocostal joints. X‐ray analysis revealed osteophyte formation within the disc space of 12‐month‐old cKO mice. Skeletal preparations confirmed calcification within the IVD and the sternocostal joints in cKO mice. H&E staining of cKO IVD revealed disorganized growth plates, delay in the formation of the bony endplate, and Col10 staining in the AF indicative of ectopic endochondral bone formation. Furthermore, proteoglycan loss was observed and collagen bundles within the inner AF were thinner and less organized. Alterations in the IVD were apparent beginning at 3 months and were progressively more visible at 6 and 12 months. Similarly, histological analysis of cKO sternocostal joints revealed joint calcification, proteoglycan loss, and disorganization of the collagen architecture at 12 months of age. Conclusions TGF‐β signaling is important for postnatal development and maintenance of fibrocartilaginous IVD and sternocostal joints.https://doi.org/10.1002/jsp2.1025annulus fibrosusend plategrowth plateintervertebral discsternum |
| spellingShingle | Bashar Alkhatib Cunren Liu Rosa Serra Tgfbr2 is required in Acan‐expressing cells for maintenance of the intervertebral and sternocostal joints JOR Spine annulus fibrosus end plate growth plate intervertebral disc sternum |
| title | Tgfbr2 is required in Acan‐expressing cells for maintenance of the intervertebral and sternocostal joints |
| title_full | Tgfbr2 is required in Acan‐expressing cells for maintenance of the intervertebral and sternocostal joints |
| title_fullStr | Tgfbr2 is required in Acan‐expressing cells for maintenance of the intervertebral and sternocostal joints |
| title_full_unstemmed | Tgfbr2 is required in Acan‐expressing cells for maintenance of the intervertebral and sternocostal joints |
| title_short | Tgfbr2 is required in Acan‐expressing cells for maintenance of the intervertebral and sternocostal joints |
| title_sort | tgfbr2 is required in acan expressing cells for maintenance of the intervertebral and sternocostal joints |
| topic | annulus fibrosus end plate growth plate intervertebral disc sternum |
| url | https://doi.org/10.1002/jsp2.1025 |
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