Caveolin-1 regulation of Sp1 controls production of the antifibrotic protein follistatin in kidney mesangial cells
Abstract Background We previously showed that caveolin-1 (cav-1), an integral membrane protein, is required for the synthesis of matrix proteins by glomerular mesangial cells (MC). In a previous study to understand how cav-1 is involved in regulating matrix production, we had identified significant...
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| Format: | Article |
| Language: | English |
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BMC
2019-04-01
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| Series: | Cell Communication and Signaling |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s12964-019-0351-5 |
| _version_ | 1818943117263372288 |
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| author | Neel Mehta Dan Zhang Renzhong Li Tony Wang Agata Gava Pavithra Parthasarathy Bo Gao Joan C. Krepinsky |
| author_facet | Neel Mehta Dan Zhang Renzhong Li Tony Wang Agata Gava Pavithra Parthasarathy Bo Gao Joan C. Krepinsky |
| author_sort | Neel Mehta |
| collection | DOAJ |
| description | Abstract Background We previously showed that caveolin-1 (cav-1), an integral membrane protein, is required for the synthesis of matrix proteins by glomerular mesangial cells (MC). In a previous study to understand how cav-1 is involved in regulating matrix production, we had identified significant upregulation of the antifibrotic protein follistatin in cav-1 knockout MC. Follistatin inhibits the profibrotic effects of several members of the transforming growth factor beta superfamily, in particular the activins. Here, we characterize the molecular mechanism through which cav-1 regulates the expression of follistatin. Methods Kidneys from cav-1 wild type and knockout (KO) mice were analyzed and primary cultures of MC from cav-1 wild-type and KO mice were utilized. FST promoter deletion constructs were generated to determine the region of the promoter important for mediating FST upregulation in cav-1 KO MC. siRNA-mediated down-regulation and overexpression of Sp1 in conjunction with luciferase activity assays, immunoprecipitation, western blotting and ChiP was used to assess the role of Sp1 in transcriptionally regulating FST expression. Pharmacologic kinase inhibitors and specific siRNA were used to determine the post-translational mechanism through which cav-1 affects Sp1 activity. Results Our results establish that follistatin upregulation occurs at the transcript level. We identified Sp1 as the critical transcription factor regulating activation of the FST promoter in cav-1 KO MC through binding to a region within 123 bp of the transcription start site. We further determined that the lack of cav-1 increases Sp1 nuclear levels and transcriptional activity. This occurred through increased phosphoinositide 3-kinase (PI3K) activity and downstream protein kinase C (PKC) zeta-mediated phosphorylation and activation of Sp1. Conclusions These findings shed light on the transcriptional mechanism by which cav-1 represses the expression of a major antifibrotic protein, and can inform the development of novel antifibrotic treatment strategies. |
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| id | doaj.art-3ed36ca02db1467e9dd977cbfd6440b7 |
| institution | Directory Open Access Journal |
| issn | 1478-811X |
| language | English |
| last_indexed | 2024-12-20T07:22:13Z |
| publishDate | 2019-04-01 |
| publisher | BMC |
| record_format | Article |
| series | Cell Communication and Signaling |
| spelling | doaj.art-3ed36ca02db1467e9dd977cbfd6440b72022-12-21T19:48:38ZengBMCCell Communication and Signaling1478-811X2019-04-0117111610.1186/s12964-019-0351-5Caveolin-1 regulation of Sp1 controls production of the antifibrotic protein follistatin in kidney mesangial cellsNeel Mehta0Dan Zhang1Renzhong Li2Tony Wang3Agata Gava4Pavithra Parthasarathy5Bo Gao6Joan C. Krepinsky7Division of Nephrology, Department of Medicine, McMaster UniversityDivision of Nephrology, Department of Medicine, McMaster UniversityDivision of Nephrology, Department of Medicine, McMaster UniversityDivision of Nephrology, Department of Medicine, McMaster UniversityPhysiological Sciences Graduate Program, Health Sciences Centre, Federal University of Espirito SantoDivision of Nephrology, Department of Medicine, McMaster UniversityDivision of Nephrology, Department of Medicine, McMaster UniversityDivision of Nephrology, Department of Medicine, McMaster UniversityAbstract Background We previously showed that caveolin-1 (cav-1), an integral membrane protein, is required for the synthesis of matrix proteins by glomerular mesangial cells (MC). In a previous study to understand how cav-1 is involved in regulating matrix production, we had identified significant upregulation of the antifibrotic protein follistatin in cav-1 knockout MC. Follistatin inhibits the profibrotic effects of several members of the transforming growth factor beta superfamily, in particular the activins. Here, we characterize the molecular mechanism through which cav-1 regulates the expression of follistatin. Methods Kidneys from cav-1 wild type and knockout (KO) mice were analyzed and primary cultures of MC from cav-1 wild-type and KO mice were utilized. FST promoter deletion constructs were generated to determine the region of the promoter important for mediating FST upregulation in cav-1 KO MC. siRNA-mediated down-regulation and overexpression of Sp1 in conjunction with luciferase activity assays, immunoprecipitation, western blotting and ChiP was used to assess the role of Sp1 in transcriptionally regulating FST expression. Pharmacologic kinase inhibitors and specific siRNA were used to determine the post-translational mechanism through which cav-1 affects Sp1 activity. Results Our results establish that follistatin upregulation occurs at the transcript level. We identified Sp1 as the critical transcription factor regulating activation of the FST promoter in cav-1 KO MC through binding to a region within 123 bp of the transcription start site. We further determined that the lack of cav-1 increases Sp1 nuclear levels and transcriptional activity. This occurred through increased phosphoinositide 3-kinase (PI3K) activity and downstream protein kinase C (PKC) zeta-mediated phosphorylation and activation of Sp1. Conclusions These findings shed light on the transcriptional mechanism by which cav-1 represses the expression of a major antifibrotic protein, and can inform the development of novel antifibrotic treatment strategies.http://link.springer.com/article/10.1186/s12964-019-0351-5Caveolin-1Mesangial cellsFollistatinSp1Renal fibrosis |
| spellingShingle | Neel Mehta Dan Zhang Renzhong Li Tony Wang Agata Gava Pavithra Parthasarathy Bo Gao Joan C. Krepinsky Caveolin-1 regulation of Sp1 controls production of the antifibrotic protein follistatin in kidney mesangial cells Cell Communication and Signaling Caveolin-1 Mesangial cells Follistatin Sp1 Renal fibrosis |
| title | Caveolin-1 regulation of Sp1 controls production of the antifibrotic protein follistatin in kidney mesangial cells |
| title_full | Caveolin-1 regulation of Sp1 controls production of the antifibrotic protein follistatin in kidney mesangial cells |
| title_fullStr | Caveolin-1 regulation of Sp1 controls production of the antifibrotic protein follistatin in kidney mesangial cells |
| title_full_unstemmed | Caveolin-1 regulation of Sp1 controls production of the antifibrotic protein follistatin in kidney mesangial cells |
| title_short | Caveolin-1 regulation of Sp1 controls production of the antifibrotic protein follistatin in kidney mesangial cells |
| title_sort | caveolin 1 regulation of sp1 controls production of the antifibrotic protein follistatin in kidney mesangial cells |
| topic | Caveolin-1 Mesangial cells Follistatin Sp1 Renal fibrosis |
| url | http://link.springer.com/article/10.1186/s12964-019-0351-5 |
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