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Cao G, Xuan X, Hu J, Zhang R, Jin H, Dong H. How vascular smooth muscle cell phenotype switching contributes to vascular disease. Cell Commun Signal 2022; 20:180. [PMID: 36411459 PMCID: PMC9677683 DOI: 10.1186/s12964-022-00993-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/22/2022] [Indexed: 11/22/2022] Open
Abstract
Vascular smooth muscle cells (VSMCs) are the most abundant cell in vessels. Earlier experiments have found that VSMCs possess high plasticity. Vascular injury stimulates VSMCs to switch into a dedifferentiated type, also known as synthetic VSMCs, with a high migration and proliferation capacity for repairing vascular injury. In recent years, largely owing to rapid technological advances in single-cell sequencing and cell-lineage tracing techniques, multiple VSMCs phenotypes have been uncovered in vascular aging, atherosclerosis (AS), aortic aneurysm (AA), etc. These VSMCs all down-regulate contractile proteins such as α-SMA and calponin1, and obtain specific markers and similar cellular functions of osteoblast, fibroblast, macrophage, and mesenchymal cells. This highly plastic phenotype transformation is regulated by a complex network consisting of circulating plasma substances, transcription factors, growth factors, inflammatory factors, non-coding RNAs, integrin family, and Notch pathway. This review focuses on phenotypic characteristics, molecular profile and the functional role of VSMCs phenotype landscape; the molecular mechanism regulating VSMCs phenotype switching; and the contribution of VSMCs phenotype switching to vascular aging, AS, and AA. Video Abstract.
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Affiliation(s)
- Genmao Cao
- grid.452845.a0000 0004 1799 2077Department of Vascular Surgery, The Second Hospital of Shanxi Medical University, No. 382, Wuyi Road, Taiyuan, China
| | - Xuezhen Xuan
- grid.452845.a0000 0004 1799 2077Department of Vascular Surgery, The Second Hospital of Shanxi Medical University, No. 382, Wuyi Road, Taiyuan, China
| | - Jie Hu
- grid.452845.a0000 0004 1799 2077Department of Vascular Surgery, The Second Hospital of Shanxi Medical University, No. 382, Wuyi Road, Taiyuan, China
| | - Ruijing Zhang
- grid.452845.a0000 0004 1799 2077Department of Nephrology, The Second Hospital of Shanxi Medical University, No. 382, Wuyi Road, Taiyuan, China
| | - Haijiang Jin
- grid.452845.a0000 0004 1799 2077Department of Vascular Surgery, The Second Hospital of Shanxi Medical University, No. 382, Wuyi Road, Taiyuan, China
| | - Honglin Dong
- grid.452845.a0000 0004 1799 2077Department of Vascular Surgery, The Second Hospital of Shanxi Medical University, No. 382, Wuyi Road, Taiyuan, China
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Jean-Charles PY, Zhang L, Wu JH, Han SO, Brian L, Freedman NJ, Shenoy SK. Ubiquitin-specific Protease 20 Regulates the Reciprocal Functions of β-Arrestin2 in Toll-like Receptor 4-promoted Nuclear Factor κB (NFκB) Activation. J Biol Chem 2016; 291:7450-64. [PMID: 26839314 DOI: 10.1074/jbc.m115.687129] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Indexed: 12/19/2022] Open
Abstract
Toll-like receptor 4 (TLR4) promotes vascular inflammatory disorders such as neointimal hyperplasia and atherosclerosis. TLR4 triggers NFκB signaling through the ubiquitin ligase TRAF6 (tumor necrosis factor receptor-associated factor 6). TRAF6 activity can be impeded by deubiquitinating enzymes like ubiquitin-specific protease 20 (USP20), which can reverse TRAF6 autoubiquitination, and by association with the multifunctional adaptor protein β-arrestin2. Although β-arrestin2 effects on TRAF6 suggest an anti-inflammatory role, physiologic β-arrestin2 promotes inflammation in atherosclerosis and neointimal hyperplasia. We hypothesized that anti- and proinflammatory dimensions of β-arrestin2 activity could be dictated by β-arrestin2's ubiquitination status, which has been linked with its ability to scaffold and localize activated ERK1/2 to signalosomes. With purified proteins and in intact cells, our protein interaction studies showed that TRAF6/USP20 association and subsequent USP20-mediated TRAF6 deubiquitination were β-arrestin2-dependent. Generation of transgenic mice with smooth muscle cell-specific expression of either USP20 or its catalytically inactive mutant revealed anti-inflammatory effects of USP20in vivoandin vitro Carotid endothelial denudation showed that antagonizing smooth muscle cell USP20 activity increased NFκB activation and neointimal hyperplasia. We found that β-arrestin2 ubiquitination was promoted by TLR4 and reversed by USP20. The association of USP20 with β-arrestin2 was augmented when β-arrestin2 ubiquitination was prevented and reduced when β-arrestin2 ubiquitination was rendered constitutive. Constitutive β-arrestin2 ubiquitination also augmented NFκB activation. We infer that pro- and anti-inflammatory activities of β-arrestin2 are determined by β-arrestin2 ubiquitination and that changes in USP20 expression and/or activity can therefore regulate inflammatory responses, at least in part, by defining the ubiquitination status of β-arrestin2.
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Affiliation(s)
| | | | - Jiao-Hui Wu
- From the Departments of Medicine (Cardiology) and
| | - Sang-Oh Han
- From the Departments of Medicine (Cardiology) and
| | - Leigh Brian
- From the Departments of Medicine (Cardiology) and
| | - Neil J Freedman
- From the Departments of Medicine (Cardiology) and Cell Biology, Duke University Medical Center, Durham, North Carolina 27710
| | - Sudha K Shenoy
- From the Departments of Medicine (Cardiology) and Cell Biology, Duke University Medical Center, Durham, North Carolina 27710
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Chaudhury A. 2D DIGE Does Not Reveal all: A Scotopic Report Suggests Differential Expression of a Single "Calponin Family Member" Protein for Tetany of Sphincters! Front Med (Lausanne) 2015; 2:42. [PMID: 26151053 PMCID: PMC4471425 DOI: 10.3389/fmed.2015.00042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 06/02/2015] [Indexed: 01/04/2023] Open
Abstract
Using 2D differential gel electrophoresis (DIGE) and mass spectrometry (MS), a recent report by Rattan and Ali (2015) compared proteome expression between tonically contracted sphincteric smooth muscles of the internal anal sphincter (IAS), in comparison to the adjacent rectum [rectal smooth muscles (RSM)] that contracts in a phasic fashion. The study showed the differential expression of a single 23 kDa protein SM22, which was 1.87 fold, overexpressed in RSM in comparison to IAS. Earlier studies have shown differences in expression of different proteins like Rho-associated protein kinase II, myosin light chain kinase, myosin phosphatase, and protein kinase C between IAS and RSM. The currently employed methods, despite its high-throughput potential, failed to identify these well-characterized differences between phasic and tonic muscles. This calls into question the fidelity and validatory potential of the otherwise powerful technology of 2D DIGE/MS. These discrepancies, when redressed in future studies, will evolve this recent report as an important baseline study of “sphincter proteome.” Proteomics techniques are currently underutilized in examining pathophysiology of hypertensive/hypotensive disorders involving gastrointestinal sphincters, including achalasia, gastroesophageal reflux disease (GERD), spastic pylorus, seen during diabetes or chronic chemotherapy, intestinal pseudo-obstruction, and recto-anal incontinence. Global proteome mapping may provide instant snapshot of the complete repertoire of differential proteins, thus expediting to identify the molecular pathology of gastrointestinal motility disorders currently labeled “idiopathic” and facilitating practice of precision medicine.
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Rattan S, Ali M. Role of SM22 in the differential regulation of phasic vs. tonic smooth muscle. Am J Physiol Gastrointest Liver Physiol 2015; 308:G605-12. [PMID: 25617350 PMCID: PMC4385893 DOI: 10.1152/ajpgi.00360.2014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 01/16/2015] [Indexed: 01/31/2023]
Abstract
Preliminary proteomics studies between tonic vs. phasic smooth muscles identified three distinct protein spots identified to be those of transgelin (SM22). The latter was found to be distinctly downregulated in the internal anal sphincter (IAS) vs. rectal smooth muscle (RSM) SMC. The major focus of the present studies was to examine the differential molecular control mechanisms by SM22 in the functionality of truly tonic smooth muscle of the IAS vs. the adjoining phasic smooth muscle of the RSM. We monitored SMC lengths before and after incubation with pFLAG-SM22 (for SM22 overexpression), and SM22 small-interfering RNA. pFLAG-SM22 caused concentration-dependent and significantly greater relaxation in the IAS vs. the RSM SMCs. Conversely, temporary silencing of SM22 caused contraction in both types of the SMCs. Further studies revealed a significant reverse relationship between the levels of SM22 phosphorylation and the amount of SM22-actin binding in the IAS and RSM SMC. Data showed higher phospho-SM22 levels and decreased SM22-actin binding in the IAS, and reverse to be the case in the RSM SMCs. Experiments determining the mechanism for SM22 phosphorylation in these smooth muscles revealed that Y-27632 (Rho kinase inhibitor) but not Gö-6850 (protein kinase C inhibitor) caused concentration-dependent decreased phosphorylation of SM22. We speculate that SM22 plays an important role in the regulation of basal tone via Rho kinase-induced phosphorylation of SM22.
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Affiliation(s)
- Satish Rattan
- Division of Gastroenterology and Hepatology, Department of Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania; and
| | - Mehboob Ali
- 2The Research Institute at Nationwide Children's Hospital, Columbus, Ohio
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Jing L, Wang W, Zhang S, Xie M, Tian D, Luo X, Wang D, Ning Q, Lü J, Wang W. Targeted inhibitory effect of Lenti-SM22alpha-p27-EGFP recombinant lentiviral vectors on proliferation of vascular smooth muscle cells without compromising re-endothelialization in a rat carotid artery balloon injury model. PLoS One 2015; 10:e0118826. [PMID: 25760326 PMCID: PMC4356572 DOI: 10.1371/journal.pone.0118826] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 01/06/2015] [Indexed: 01/04/2023] Open
Abstract
AIMS In-stent restenosis remains a serious problem after the implantation of drug-eluting stents, which is attributable to neointima formation and re-endothelialization. Here, we tried to find a new method which aims at selectively inhibiting proliferation of vascular smooth muscle cells (VSMC) proliferation without inhibition of re-endothelialization. METHODS AND RESULTS We used the smooth muscle-specific SM22alpha promoter in a recombinant lentiviral vector to drive overexpression of cell-cycle inhibitor, p27, in VSMCs. p27 effectively inhibited VSMC proliferation mediated by cell cycle arrest at the G0/G1 checkpoint. The SM22alpha-p27 lentiviral vector inhibited VSMC proliferation more effectively than paclitaxel. Rats infected with Lenti-SM22alpha-p27 had a significantly lower intima/media (I/M) ratio and also showed inhibition of restenosis on day 28 after balloon injury. Moreover, the repair of injured endothelium, and re-endothelialization of the carotid artery wall, was not affected by the smooth muscle cell-specific expression of p27. CONCLUSION A recombinant lentiviral vector carrying the SM22alpha promoter was used to effectively infect and selectively overexpress p27 protein in VSMCs, leading to inhibition of intimal hyperplasia without compromising endothelial repair.
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Affiliation(s)
- Liang Jing
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Wenlong Wang
- Department of Cardiovascular Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, China
| | - Shuangshuang Zhang
- Department of Cardiovascular Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, China
| | - Minjie Xie
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Daishi Tian
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Xiang Luo
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Daowen Wang
- Department of Cardiovascular Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, China
| | - Qin Ning
- Department and Institute of Infectious Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Jiagao Lü
- Department of Cardiovascular Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, China
- * E-mail: (WW); (JL)
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
- * E-mail: (WW); (JL)
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Kaci-Ouchfoun N, Izemrane D, Boudrissa A, Gernigon T, Khammar F, Exbrayat JM. Transgelin: an androgen-dependent protein identified in the seminal vesicles of three Saharan rodents. Theriogenology 2013; 80:748-57. [PMID: 23906482 DOI: 10.1016/j.theriogenology.2013.06.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 06/22/2013] [Accepted: 06/23/2013] [Indexed: 12/06/2022]
Abstract
During the breeding season, a major androgen-dependent protein with an apparent molecular weight of 21 kDa was isolated and purified from the seminal vesicles of three Saharan rodents (MLVSP21 from Meriones libycus, MSVSP21 from Meriones shawi, and MCVSP21 from Meriones crassus). The 21-kDa protein was isolated and purified from soluble seminal vesicle proteins of homogenate by one-dimensional polyacrylamide gel electrophoresis (SDS-PAGE). Using polyclonal antibodies directed against POSVP21 (Psammomys obesus seminal vesicles protein of 21 kDa), a major androgen-dependent secretory protein from sand rat seminal vesicles, identified previously as transgelin, we showed an immunological homology with POSVP21 by immunoblotting. These three major androgen-dependent proteins with a same apparent molecular weight of 21 kDa designated as MLVSP21 (Meriones libycus seminal vesicles protein of 21 kDa), MSVSP21 (Meriones shawi seminal vesicles protein of 21 kDa), and MCVSP21 (Meriones crassus seminal vesicles protein of 21 kDa) were localized by immunohistochemistry and identified by applying a proteomic approach. Our results indicated that the isolated proteins MLSVP21, MSSVP21, and MCSVP21 seem to correspond to the same protein: the transgelin. So that transgelin can be used as a specific marker of these rodent physiological reproduction mechanisms.
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Affiliation(s)
- Naïma Kaci-Ouchfoun
- Laboratory of Arid Areas, Biological Sciences Institute, USTHB, Algiers, Algeria.
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Haase R, Magnusson T, Su B, Kopp F, Wagner E, Lipps H, Baiker A, Ogris M. Generation of a tumor- and tissue-specific episomal non-viral vector system. BMC Biotechnol 2013; 13:49. [PMID: 23734827 PMCID: PMC3728224 DOI: 10.1186/1472-6750-13-49] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 05/28/2013] [Indexed: 02/08/2023] Open
Abstract
Background A key issue for safe and reproducible gene therapy approaches is the autologous and tissue-specific expression of transgenes. Tissue-specific expression in vivo is either achieved by transfer vectors that deliver the gene of interest into a distinct cell type or by use of tissue-specific expression cassettes. Here we present the generation of non-viral, episomally replicating vectors that are able to replicate in a tissue specific manner thus allowing tissue specific transgene expression in combination with episomal replication. The episomal replication of the prototype vector pEPI-1 and its derivatives depends exclusively on a transcription unit starting from a constitutively active promoter extending into the scaffold/matrix attachment region (S/MAR). Results Here, we exchanged the constitutive promoter in the pEPI derivative pEPito by the tumor specific alpha fetoprotein (AFP) or the muscle specific smooth muscle 22 (SM22) promoter leading to specific transgene expression in AFP positive human hepatocellular carcinoma (HUH7) and in a SM22 positive cell line, respectively. The incorporation of the hCMV enhancer element into the expression cassette further boosted the expression levels with both promoters. Tissue specific-replication could be exemplary proven for the smooth muscle protein 22 (SM22) promoter in vitro. With the AFP promoter-driven pEPito vector hepatocellular carcinoma-specific expression could be achieved in vivo after systemic vector application together with polyethylenimine as transfection enhancer. Conclusions In this study we present an episomal plasmid system designed for tissue specific transgene expression and replication. The human AFP-promoter in combination with the hCMV enhancer element was demonstrated to be a valuable tissue-specific promoter for targeting hepatocellular carcinomas with non-viral gene delivery system, and tissue specific replication could be shown in vitro with the muscle specific SM22 promoter. In combination with appropriate delivery systems, the tissue specific pEPito vector system will allow higher tissue-specificity with less undesired side effects and is suitable for long term transgene expression in vivo within gene therapeutical approaches.
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Affiliation(s)
- Rudolf Haase
- Department of Pharmacy, Center for Drug Research, Pharmaceutical Biotechnology, Ludwig-Maximilians-University, Munich, Germany.
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Sohni A, Mulas F, Ferrazzi F, Luttun A, Bellazzi R, Huylebroeck D, Ekker SC, Verfaillie CM. TGFβ1-induced Baf60c regulates both smooth muscle cell commitment and quiescence. PLoS One 2012; 7:e47629. [PMID: 23110084 PMCID: PMC3482188 DOI: 10.1371/journal.pone.0047629] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 09/13/2012] [Indexed: 02/02/2023] Open
Abstract
Smooth muscle cells (SMCs) play critical roles in a number of diseases; however, the molecular mechanism underlying their development is unclear. Although the role of TGFβ1 signaling in SMC development is well established, the downstream molecular signals are not fully understood. We used several rat multipotent adult progenitor cell ((r)MAPC) lines that express levels of Oct4 mRNA similar to hypoblast stem cells (HypoSC), and can differentiate robustly to mesodermal and endodermal cell types. TGFβ1 alone, or with PDGF-BB, induces differentiation of rMAPCs to SMCs, which expressed structural SMC proteins, including α-smooth muscle actin (αSMA), and contribute to the SMC coat of blood vessels in vivo. A genome-wide time-course transcriptome analysis revealed that transcripts of Baf60c, part of the SWI/SNF actin binding chromatin remodeling complex D-3 (SMARCD3/BAF60c), were significantly induced during MAPC-SMC differentiation. We demonstrated that BAF60c is a necessary co-regulator of TGFβ1 mediated induction of SMC genes. Knock-down of Baf60c decreased SMC gene expression in rMAPCs whereas ectopic expression of Baf60c was sufficient to commit rMAPCs to SMCs in the absence of exogenous cytokines. TGFβ1 activates Baf60c via the direct binding of SMAD2/3 complexes to the Baf60c promoter region. Chromatin- and co-immunoprecipitation studies demonstrated that regulation of SMC genes by BAF60c is mediated via interaction with SRF binding CArG box-containing promoter elements in SMC genes. We noted that compared with TGFβ1, Baf60c overexpression in rMAPC yielded SMC with a more immature phenotype. Similarly, Baf60c induced an immature phenotype in rat aortic SMCs marked by increased cell proliferation and decreased contractile marker expression. Thus, Baf60c is important for TGFβ-mediated commitment of primitive stem cells (rMAPCs) to SMCs and is associated with induction of a proliferative state of quiescent SMCs. The MAPC-SMC differentiation system may be useful for identification of additional critical (co-)regulators of SMC development.
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Affiliation(s)
- Abhishek Sohni
- Stem Cell Institute, Department of Development and Regeneration, K.U.Leuven, Leuven, Belgium
- Genetics Cell and Developmental Biology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Francesca Mulas
- Center for Tissue Engineering, University of Pavia, Pavia, Italy
| | - Fulvia Ferrazzi
- Dipartimento di Informatica e Sistemistica, University of Pavia, Pavia, Italy
| | - Aernout Luttun
- Center for Molecular and Vascular Biology, K.U.Leuven, Leuven, Belgium
| | - Riccardo Bellazzi
- Center for Tissue Engineering, University of Pavia, Pavia, Italy
- Dipartimento di Informatica e Sistemistica, University of Pavia, Pavia, Italy
| | - Danny Huylebroeck
- Laboratory of Molecular Biology (Celgen), Department of Development and Regeneration, K.U.Leuven, Leuven, Belgium
| | - Stephen C. Ekker
- Genetics Cell and Developmental Biology, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Catherine M. Verfaillie
- Stem Cell Institute, Department of Development and Regeneration, K.U.Leuven, Leuven, Belgium
- Genetics Cell and Developmental Biology, University of Minnesota, Minneapolis, Minnesota, United States of America
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Yu K, Zheng B, Han M, Wen JK. ATRA activates and PDGF-BB represses the SM22α promoter through KLF4 binding to, or dissociating from, its cis-DNA elements. Cardiovasc Res 2011; 90:464-74. [DOI: 10.1093/cvr/cvr017] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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SM22α inhibits cell proliferation and protects against anticancer drugs and γ-radiation in HepG2 cells: Involvement of metallothioneins. FEBS Lett 2009; 583:3356-62. [DOI: 10.1016/j.febslet.2009.09.040] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 09/21/2009] [Accepted: 09/23/2009] [Indexed: 11/23/2022]
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Han GH, Shin HJ, Kim SW. Optimization of bio-indigo production by recombinant E. coli harboring fmo gene. Enzyme Microb Technol 2008. [DOI: 10.1016/j.enzmictec.2008.02.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Wang C, Han M, Zhao XM, Wen JK. Kruppel-like factor 4 is required for the expression of vascular smooth muscle cell differentiation marker genes induced by all-trans retinoic acid. J Biochem 2008; 144:313-21. [PMID: 18511453 DOI: 10.1093/jb/mvn068] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Krüppel-like factor 4 (KLF4) is involved in phenotypic modulation of vascular smooth muscle cells (VSMCs). All-trans retinoic acid (ATRA) inhibits VSMC proliferation and induces VSMC differentiation. However, the role of KLF4 in ATRA-elicited VSMC phenotypic modulation remains unclear. Here, we show that treatment of VSMCs with ATRA resulted in significant inhibition of proliferation and migration of VSMCs, as well as up-regulation of KLF4 and the VSMC differentiation marker genes SM22alpha and SM alpha-actin (alpha-SMA). At the same time, the KLF4 target gene p53 was up-regulated, while the VSMC dedifferentiation marker gene nonmuscle myosin heavy chain-B (SMemb) was down-regulated. We also show that overexpression of KLF4 in VSMCs increased the expression of p53, SM22alpha and alpha-SMA, but decreased the expression of SMemb and VSMC proliferation and migration. Silencing of KLF4 expression by KLF4-specific small interfering RNA (siRNA) abrogated the inducing effects of ATRA on p53, SM22alpha and alpha-SMA expression and neutralized the inhibitory effects of ATRA on SMemb expression and VSMC proliferation and migration. Thus, our data suggest that KLF4 is required for the expression of VSMC differentiation marker genes induced by ATRA and that this transcription factor is one of the key mediators of retinoid actions in VSMCs.
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Affiliation(s)
- Chao Wang
- Department of Biochemistry and Molecular Biology, Hebei Medical University, Shijiazhuang 050017, China
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Favot L, Hall SM, Haworth SG, Kemp PR. Cytoplasmic YY1 is associated with increased smooth muscle-specific gene expression: implications for neonatal pulmonary hypertension. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 167:1497-509. [PMID: 16314465 PMCID: PMC1613200 DOI: 10.1016/s0002-9440(10)61236-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Immediately after birth the adluminal vascular SMCs of the pulmonary elastic arteries undergo transient actin cytoskeletal remodeling as well as cellular de-differentiation and proliferation. Vascular smooth muscle phenotype is regulated by serum response factor, which is itself regulated in part by the negative regulator YY1. We therefore studied the subcellular localization of YY1 in arteries of normal newborn piglets and piglets affected by neonatal pulmonary hypertension. We found that YY1 localization changed during development and that expression of gamma-smooth muscle actin correlated with expression of cytoplasmic rather than nuclear YY1. Analysis of the regulation of YY1 localization in vitro demonstrated that polymerized gamma-actin sequestered EGFP-YY1 in the cytoplasm and that YY1 activation of c-myc promoter activity was inhibited by LIM kinase, which increases actin polymerization. Consistent with these data siRNA-mediated down-regulation of YY1 in C2C12 cells increased SM22-alpha expression and inhibited cell proliferation. Thus, actin polymerization controls subcellular YY1 localization, which contributes to vascular SMC proliferation and differentiation in normal pulmonary artery development. In the absence of actin depolymerization, YY1 does not relocate to the nucleus, and this lack of relocation may contribute to the pathobiology of pulmonary hypertension.
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Affiliation(s)
- Laure Favot
- Department of Biochemistry, Section of Cardiovascular Biology, University of Cambridge, UK
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14
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Favot L, Gillingwater M, Scott C, Kemp PR. Overexpression of a family of RPEL proteins modifies cell shape. FEBS Lett 2005; 579:100-4. [PMID: 15620697 DOI: 10.1016/j.febslet.2004.11.054] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2004] [Revised: 11/01/2004] [Accepted: 11/04/2004] [Indexed: 11/25/2022]
Abstract
Proteins containing RPEL motifs (e.g., MAL) are important in the regulation of gene expression by the actin cytoskeleton. Screening the ENSEMBL database for RPEL proteins identified four additional proteins that contain RPEL motifs and nuclear localisation sequences, three of which (RPEL-A, RPEL-B and RPEL-C) are expressed in adult mouse tissues with different expression profiles. The mRNAs encoding RPEL-B and RPEL-C were subject to alternative splicing. Expression of these genes in cells indicated that they had a marked effect on cell shape. Furthermore, when expressed with a nuclear localised actin all of the different forms became restricted to the nucleus.
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Affiliation(s)
- Laure Favot
- Department of Biochemistry, University of Cambridge, Building O, Downing Site, Tennis Court Road, Cambridge CB2 1QW, UK
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Owens GK, Kumar MS, Wamhoff BR. Molecular regulation of vascular smooth muscle cell differentiation in development and disease. Physiol Rev 2004; 84:767-801. [PMID: 15269336 DOI: 10.1152/physrev.00041.2003] [Citation(s) in RCA: 2549] [Impact Index Per Article: 127.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The focus of this review is to provide an overview of the current state of knowledge of molecular mechanisms/processes that control differentiation of vascular smooth muscle cells (SMC) during normal development and maturation of the vasculature, as well as how these mechanisms/processes are altered in vascular injury or disease. A major challenge in understanding differentiation of the vascular SMC is that this cell can exhibit a wide range of different phenotypes at different stages of development, and even in adult organisms the cell is not terminally differentiated. Indeed, the SMC is capable of major changes in its phenotype in response to changes in local environmental cues including growth factors/inhibitors, mechanical influences, cell-cell and cell-matrix interactions, and various inflammatory mediators. There has been much progress in recent years to identify mechanisms that control expression of the repertoire of genes that are specific or selective for the vascular SMC and required for its differentiated function. One of the most exciting recent discoveries was the identification of the serum response factor (SRF) coactivator gene myocardin that appears to be required for expression of many SMC differentiation marker genes, and for initial differentiation of SMC during development. However, it is critical to recognize that overall control of SMC differentiation/maturation, and regulation of its responses to changing environmental cues, is extremely complex and involves the cooperative interaction of many factors and signaling pathways that are just beginning to be understood. There is also relatively recent evidence that circulating stem cell populations can give rise to smooth muscle-like cells in association with vascular injury and atherosclerotic lesion development, although the exact role and properties of these cells remain to be clearly elucidated. The goal of this review is to summarize the current state of our knowledge in this area and to attempt to identify some of the key unresolved challenges and questions that require further study.
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MESH Headings
- Aging/metabolism
- Animals
- Arteriosclerosis/genetics
- Cell Differentiation
- Cellular Senescence
- Embryo, Mammalian/cytology
- Embryo, Mammalian/metabolism
- Humans
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/embryology
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/cytology
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- Phenotype
- Vascular Diseases/genetics
- Vascular Diseases/metabolism
- Vascular Diseases/pathology
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Affiliation(s)
- Gary K Owens
- Dept. of Molecular Physiology and Biological Physics, Univ. of Virginia School of Medicine, 415 Lane Rd., Medical Research Building 5, Rm. 1220, PO Box 801394, Charlottesville, VA 22908, USA.
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16
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West J, Fagan K, Steudel W, Fouty B, Lane K, Harral J, Hoedt-Miller M, Tada Y, Ozimek J, Tuder R, Rodman DM. Pulmonary Hypertension in Transgenic Mice Expressing a Dominant-Negative BMPRII Gene in Smooth Muscle. Circ Res 2004; 94:1109-14. [PMID: 15031260 DOI: 10.1161/01.res.0000126047.82846.20] [Citation(s) in RCA: 185] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bone morphogenetic peptides (BMPs), a family of cytokines critical to normal development, were recently implicated in the pathogenesis of familial pulmonary arterial hypertension. The type-II receptor (BMPRII) is required for recognition of all BMPs, and targeted deletion of BMPRII in mice results in fetal lethality before gastrulation. To overcome this limitation and study the role of BMP signaling in postnatal vascular disease, we constructed a smooth muscle–specific transgenic mouse expressing a dominant-negative BMPRII under control of the tetracycline gene switch (SM22-tet-BMPRII
delx4+
mice). When the mutation was activated after birth, mice developed increased pulmonary artery pressure, RV/LV+S ratio, and pulmonary arterial muscularization with no increase in systemic arterial pressure. Studies with SM22-tet-BMPRII
delx4+
mice support the hypothesis that loss of BMPRII signaling in smooth muscle is sufficient to produce the pulmonary hypertensive phenotype.
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MESH Headings
- Animals
- Blood Pressure
- Bone Morphogenetic Protein Receptors, Type II
- Doxycycline/pharmacology
- Genes, Dominant
- Genetic Predisposition to Disease
- Genotype
- Humans
- Hypertension, Pulmonary/genetics
- Hypertension, Pulmonary/metabolism
- Hypertension, Pulmonary/pathology
- Lung/pathology
- Mice
- Mice, Transgenic
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Organ Specificity
- Phenotype
- Promoter Regions, Genetic/drug effects
- Protein Serine-Threonine Kinases/deficiency
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/physiology
- Pulmonary Artery/physiopathology
- Pulmonary Artery/ultrastructure
- Transfection
- Transgenes
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Affiliation(s)
- James West
- University of Colorado Health Sciences Center, Division of Pulmonary Sciences and Critical Care Medicine and Department of Anesthesia, Denver, Colo 80262, USA
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17
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Herrmann J, Arias M, Van De Leur E, Gressner AM, Weiskirchen R. CSRP2, TIMP-1, and SM22alpha promoter fragments direct hepatic stellate cell-specific transgene expression in vitro, but not in vivo. Liver Int 2004; 24:69-79. [PMID: 15102003 DOI: 10.1111/j.1478-3231.2004.00891.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND/AIMS The activation of hepatic stellate cells (HSC) and their transdifferentiation into myofibroblasts (MFB) is the key step for development of liver fibrosis. Over the past several years, significant progress has been made in the understanding of the critical pathways involved incells undergoing activation. Cellular activation in the course of transdifferentiation involves, among other biochemical modifications, functionally relevant changes in the control of gene expression. These include the up-regulation of transcription factors, different extracellular matrix proteins, cell adhesion molecules, smooth muscle specific genes, and proteins involved in matrix remodelling, or cytoskeletal organization. The corresponding regulatory elements of these genes have afforded us the opportunity to express transgenes with antifibrotic potential in a cell type- and/or transdifferentiation-dependent manner. METHODS In the present study, we have tested several promoters for their ability to mediate cell-specific expression, including those for CSRP2, SM22alpha, and TIMP-1 (CSRP2, gene encoding the LIM domain protein CRP2; SM22alpha, smooth muscle-specific gene encoding a 22-kDa protein; TIMP-1, gene encoding the tissue inhibitor of metalloproteinases-1), which in liver are specifically expressed in HSC or become strongly activated during the acute remodelling into MFB. We constructed adenoviral reporter vectors in which relevant portions of the promoters were fused to the green fluorescent protein. RESULTS AND CONCLUSION Our experiments demonstrate that each of these promoters is sufficient to achieve strong or partially selective expression in vitro but none is able to direct a specific or inducible expression of transgenes in HSC/MFB in vivo.
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Affiliation(s)
- Jens Herrmann
- Institute of Clinical Chemistry and Pathobiochemistry, RWTH-University Hospital, Aachen, Germany
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18
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Martin KM, Ellis PD, Metcalfe JC, Kemp PR. Selective modulation of the SM22alpha promoter by the binding of BTEB3 (basal transcription element-binding protein 3) to TGGG repeats. Biochem J 2003; 375:457-63. [PMID: 12848620 PMCID: PMC1223682 DOI: 10.1042/bj20030870] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2003] [Accepted: 07/09/2003] [Indexed: 01/12/2023]
Abstract
We have previously identified a C2H2 zinc-finger transcription factor [BTEB3 (basal transcription element-binding protein 3)/KLF13 (Krüppel-like factor 13)] that activates the minimal promoter for the smooth muscle-specific SM22alpha gene in other types of cell. We show that recombinant BTEB3 binds to three TGGG motifs in the minimal SM22alpha promoter. By mutation analysis, only one of these boxes is required for BTEB3-dependent promoter activation in P19 cells and BTEB3 activates or inhibits reporter gene expression depending on the TGGG box to which it binds. Transient transfection experiments show that BTEB3 also activates reporter gene expression from the SM22alpha promoter in VSMCs (vascular smooth muscle cells). Similar studies showed that BTEB3 did not activate expression from the promoter regions of the smooth muscle myosin heavy chain or smooth muscle alpha-actin promoters, which contain similar sequences, implying that promoter activation by BTEB3 is selective. The expression of BTEB3 is readily detectable in VSMCs in vitro and is modulated in response to injury in vivo.
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MESH Headings
- Animals
- Base Sequence
- Binding Sites/genetics
- Carotid Artery Injuries/genetics
- Cell Line, Tumor
- Cells, Cultured
- Conserved Sequence/genetics
- DNA/genetics
- DNA/metabolism
- Electrophoretic Mobility Shift Assay
- Gene Expression Regulation
- In Situ Hybridization
- Microfilament Proteins/genetics
- Microsatellite Repeats
- Muscle Proteins/genetics
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Promoter Regions, Genetic/genetics
- Protein Binding
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Sequence Homology, Nucleic Acid
- Trans-Activators/genetics
- Trans-Activators/metabolism
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Affiliation(s)
- Karen M Martin
- Section of Cardiovascular Biology, Department of Biochemistry, University of Cambridge, Building O, Downing Site, Cambridge CB2 1QW, U.K
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19
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Kaplan-Albuquerque N, Garat C, Desseva C, Jones PL, Nemenoff RA. Platelet-derived growth factor-BB-mediated activation of Akt suppresses smooth muscle-specific gene expression through inhibition of mitogen-activated protein kinase and redistribution of serum response factor. J Biol Chem 2003; 278:39830-8. [PMID: 12882977 DOI: 10.1074/jbc.m305991200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Platelet-derived growth factor (PDGF) inhibits expression of smooth muscle (SM) genes in vascular smooth muscle cells and blocks induction by arginine vasopressin (AVP). We have previously demonstrated that suppression of SM-alpha-actin by PDGF-BB is mediated in part through a Ras-dependent pathway. This study examined the role of phosphatidylinositol 3-kinase (PI3K)y and its downstream effector, Akt, in regulating SM gene expression. PDGF caused a rapid sustained activation of Akt, whereas AVP caused only a small transient increase. PDGF selectively caused a sustained stimulation of p85/p110 alpha PI3K. In contrast, p85/110 beta PI3K activity was not altered by either PDGF or AVP, whereas both agents caused a delayed activation of Class IB p101/110 gamma PI3K. Expression of a gain-of-function PI3K or myristoylated Akt (myr-Akt) mimicked the inhibitory effect of PDGF on SM-alpha-actin and SM22 alpha expression. Pretreatment with LY 294002 reversed the inhibitory effect of PDGF. Expression of myr-Akt selectively inhibited AVP-induced activation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinases, which we have shown are critical for induction of these genes. Nuclear extracts from PDGF-stimulated or myr-Akt expressing cells showed reduced serum response factor binding to SM-specific CArG elements. This was associated with appearance of serum response factor in the cytoplasm. These data indicate that activation of p85/p110 alpha/Akt mediates suppression of SM gene expression by PDGF.
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Affiliation(s)
- Nihal Kaplan-Albuquerque
- Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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20
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Kaplan-Albuquerque N, Garat C, Van Putten V, Nemenoff RA. Regulation of SM22 alpha expression by arginine vasopressin and PDGF-BB in vascular smooth muscle cells. Am J Physiol Heart Circ Physiol 2003; 285:H1444-52. [PMID: 12829429 DOI: 10.1152/ajpheart.00306.2003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Vascular smooth muscle (SM) cells (VSMC) undergo phenotypic modulation in vivo and in vitro. This process involves coordinated changes in expression of multiple SM-specific genes. In cultured VSMC, arginine vasopressin (AVP) increases and PDGF decreases expression of SM alpha-actin (SMA), the earliest marker of SM cells (SMC). However, it is unknown whether these agents regulate other SM genes in a similar fashion. SM22 alpha appears secondary to SMA during development and is also a marker for SMC. This study examined the regulation of SM22 alpha expression by AVP and PDGF in cultured VSMC. Levels of SM22 alpha mRNA and protein were increased by AVP and suppressed by PDGF. Consistent with these changes, AVP increased SM22 alpha promoter activity, whereas PDGF inhibited basal promoter activity and blocked AVP-induced increase. Activation of both JNK and p38 MAPK pathways was necessary for AVP-mediated induction of SM22 alpha promoter. Expression of constitutively active Ras produced similar suppressions on SM22 alpha promoter activity as PDGF. Signaling relayed from PDGF/Ras activation involved Raf, or a protein that competes for this site, Ral-GDS, and phosphatidylinositol 3-kinase activation. Truncational analysis showed that the proximal location of three CArG boxes in the promoter was sufficient for AVP stimulation. Mutations in this CArG box reduced basal and AVP-stimulated promoter activity without effecting PDGF suppression. Overexpression of serum response factor enhanced basal and AVP-stimulated promoter activity but had no effect on PDGF-BB-induced suppression. These data indicate that AVP and PDGF initiate specific signaling pathways that control expression of multiple SM genes leading to phenotypic modulation.
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MESH Headings
- Animals
- Arginine Vasopressin/pharmacology
- Becaplermin
- Cells, Cultured
- Electrophoresis, Polyacrylamide Gel
- Gene Expression/physiology
- Gene Expression Regulation/physiology
- Microfilament Proteins/genetics
- Microfilament Proteins/metabolism
- Mitogen-Activated Protein Kinases/metabolism
- Muscle Proteins/genetics
- Muscle Proteins/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Platelet-Derived Growth Factor/pharmacology
- Promoter Regions, Genetic/drug effects
- Promoter Regions, Genetic/physiology
- Proto-Oncogene Proteins c-sis
- Rats
- Signal Transduction/physiology
- Vasoconstrictor Agents/pharmacology
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Affiliation(s)
- Nihal Kaplan-Albuquerque
- Department of Medicine, University of Colorado Health Sciences Center, 4200 E. Ninth Ave., Denver, CO 80262, USA
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21
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Afroze T, Yang LL, Wang C, Gros R, Kalair W, Hoque AN, Mungrue IN, Zhu Z, Husain M. Calcineurin-independent regulation of plasma membrane Ca2+ ATPase-4 in the vascular smooth muscle cell cycle. Am J Physiol Cell Physiol 2003; 285:C88-95. [PMID: 12660151 DOI: 10.1152/ajpcell.00518.2002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Calcineurin mediates repression of plasma membrane Ca2+-ATPase-4 (PMCA4) expression in neurons, whereas c-Myb is known to repress PMCA1 expression in vascular smooth muscle cells (VSMC). Here, we describe a novel mouse VSMC line (MOVAS) in which 45Ca efflux rates decreased 50%, fura 2-AM-based intracellular Ca2+ concentrations ([Ca2+]i) increased twofold, and real-time RT-PCR and Western blot revealed a approximately 40% decrease in PMCA4 expression levels from G0 to G1/S in the cell cycle, where PMCA4 constituted approximately 20% of total PMCA protein. Although calcineurin activity increased fivefold as MOVAS progressed from G0 to G1/S, inhibition of this increase with either BAPTA or retroviral transduction with peptide inhibitors of calcineurin (CAIN), or its downstream target nuclear factor of activated T cells (NFAT) (VIVIT), had no effect on the repression of PMCA4 mRNA expression at G1/S. By contrast, Ca2+-independent activity of the calmodulin-dependent protein kinase-II (CaMK-II) increased eightfold as MOVAS progressed from G0 to G1/S, and treatment with an inhibitor of CaMK-II (KN-93) or transduction of a c-Myb-neutralizing antibody significantly alleviated the G1/S-associated repression of PMCA4. These data show that G1/S-specific PMCA4 repression in proliferating VSMC is brought about by c-Myb and CaMK-II and that calcineurin may regulate cell cycle-associated [Ca2+]i through alternate targets.
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Affiliation(s)
- Talat Afroze
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada M5G-2C4
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22
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King KE, Iyemere VP, Weissberg PL, Shanahan CM. Krüppel-like factor 4 (KLF4/GKLF) is a target of bone morphogenetic proteins and transforming growth factor beta 1 in the regulation of vascular smooth muscle cell phenotype. J Biol Chem 2003; 278:11661-9. [PMID: 12538588 DOI: 10.1074/jbc.m211337200] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Vascular smooth muscle cell (VSMC) differentiation and phenotypic modulation is characterized by changes in mRNA expression for smooth muscle (SM) marker contractile proteins such as alpha-SM actin and SM22 alpha. Transforming growth factor beta1 (TGF-beta 1) is a potent VSMC differentiation factor; however, it is not known if other TGF-beta-superfamily members, in particular the bone morphogenetic proteins (BMPs), modulate VSMC phenotype. Here we demonstrate that a large subset of TGF-beta-superfamily members and their type I receptors are differentially co-expressed as VSMC phenotype changes during fetal/neonatal development and that BMP2, -4, and -6 reciprocally regulate SM-marker mRNA and protein expression in vitro. BMP2 and BMP6 decrease expression of the SM markers alpha-SM actin, SM22alpha, and calponin in rat VSMCs, whereas BMP4 increases their expression. The effects of BMP-2, -4, and -6 on SM marker gene transcription are mediated through a consensus TGF-beta-controlling element, the TCE, which is common to regulatory regions of SM-marker genes. Moreover, co-treatment experiments revealed that BMP-2, -4, and -6 each inhibit TGF-beta 1-modulated increases in SM22alpha reporter gene activity. Regardless of whether they positively or negatively regulate SM marker expression, TGF-beta 1 and BMP-2, -4, and -6 all induced binding of the Krüppel-like transcription factor, GKLF/KLF4, to the TGF-beta control element. Induction of KLF4 was confirmed by immunocytochemistry and Western blotting, which revealed that a lower molecular weight KLF4 protein is induced after treatment with TGF-beta-superfamily members. Taken together, our results demonstrate that multiple members of the TGF-beta superfamily act in concert to modulate VSMC phenotype.
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Affiliation(s)
- Kathryn E King
- University of Cambridge, Department of Medicine, Addenbrooke's Centre for Clinical Investigation Level 6, Box 110 Addenbrooke's Hospital, Hills Rd., Cambridge CB2 2QQ, United Kingdom
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23
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Hoggatt AM, Simon GM, Herring BP. Cell-specific regulatory modules control expression of genes in vascular and visceral smooth muscle tissues. Circ Res 2002; 91:1151-9. [PMID: 12480816 DOI: 10.1161/01.res.0000047508.30800.4f] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A novel approach with chimeric SM22alpha/telokin promoters was used to identify gene regulatory modules that are required for regulating the expression of genes in distinct smooth muscle tissues. Conventional deletion or mutation analysis of promoters does not readily distinguish regulatory elements that are required for basal gene expression from those required for expression in specific smooth muscle tissues. In the present study, the mouse telokin gene was isolated, and a 370-bp (-190 to 180) minimal promoter was identified that directs visceral smooth muscle-specific expression in vivo in transgenic mice. The visceral smooth muscle-specific expression of the telokin promoter transgene is in marked contrast to the reported arterial smooth muscle-specific expression of a 536-bp minimal SM22alpha (-475 to 61) promoter transgene. To begin to identify regulatory elements that are responsible for the distinct tissue-specific expression of these promoters, a chimeric promoter in which a 172-bp SM22alpha gene fragment (-288 to -116) was fused to the minimal telokin promoter was generated and characterized. The -288 to -116 SM22alpha gene fragment significantly increased telokin promoter activity in vascular smooth muscle cells in vitro and in vivo. Conversely, a fragment of the telokin promoter (-94 to -49) increased the activity of the SM22alpha promoter in visceral smooth muscle cells of the bladder. Together, these data demonstrate that both vascular- and visceral smooth muscle-specific regulatory modules direct gene expression in subsets of smooth muscle tissues.
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MESH Headings
- AT Rich Sequence/physiology
- Animals
- Animals, Newborn
- Brain/metabolism
- Cells, Cultured
- Fibroblasts/cytology
- Fibroblasts/metabolism
- Gene Expression Regulation/physiology
- Gene Targeting
- Genes, Reporter
- Mice
- Mice, Transgenic
- Microfilament Proteins/genetics
- Molecular Sequence Data
- Muscle Proteins/genetics
- Muscle, Smooth/cytology
- Muscle, Smooth/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Myosin-Light-Chain Kinase
- Organ Specificity
- Peptide Fragments
- Peptides
- Promoter Regions, Genetic/genetics
- Regulatory Sequences, Nucleic Acid/genetics
- Sequence Analysis, DNA
- Transfection
- Transgenes
- Urinary Bladder/metabolism
- Viscera/metabolism
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Affiliation(s)
- April M Hoggatt
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis 46202, USA
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24
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Ellis PD, Martin KM, Rickman C, Metcalfe JC, Kemp PR. Increased actin polymerization reduces the inhibition of serum response factor activity by Yin Yang 1. Biochem J 2002; 364:547-54. [PMID: 12023898 PMCID: PMC1222600 DOI: 10.1042/bj20020269] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recent evidence has implicated CC(A/T(richG))GG (CArG) boxes, binding sites for serum response factor (SRF), in the regulation of expression of a number of genes in response to changes in the actin cytoskeleton. In many cases, the activity of SRF at CArG boxes is modulated by transcription factors binding to overlapping (e.g. Yin Yang 1, YY1) or adjacent (e.g. ets) binding sites. However, the mechanisms by which SRF activity is regulated by the cytoskeleton have not been determined. To investigate these mechanisms, we screened for cells that did or did not increase the activity of a fragment of the promoter for a smooth-muscle (SM)-specific gene SM22alpha, in response to changes in actin cytoskeletal polymerization induced by LIM kinase. These experiments showed that vascular SM cells (VSMCs) and C2C12 cells increased the activity of promoters containing at least one of the SM22alpha CArG boxes (CArG near) in response to LIM kinase, whereas P19 cells did not. Bandshift assays using a probe to CArG near showed that P19 cells lacked detectable YY1 DNA binding to the CArG box in contrast with the other two cell types. Expression of YY1 in P19 cells inhibited SM22alpha promoter activity and conferred responsiveness to LIM kinase. Mutation of the CArG box to inhibit YY1 or SRF binding indicated that both factors were required for the LIM kinase response in VSMCs and C2C12 cells. The data indicate that changes in the actin cytoskeletal organization modify SRF activity at CArG boxes by modulating YY1-dependent inhibition.
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Affiliation(s)
- Peter D Ellis
- Section of Cardiovascular Biology, Department of Biochemistry, University of Cambridge, Building O, Downing Site, Cambridge CB2 1QW, UK
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25
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Morgan KG, Gangopadhyay SS. Invited review: cross-bridge regulation by thin filament-associated proteins. J Appl Physiol (1985) 2001; 91:953-62. [PMID: 11457814 DOI: 10.1152/jappl.2001.91.2.953] [Citation(s) in RCA: 179] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
This minireview will cover current concepts on the identity and mechanistic function of smooth muscle actin binding proteins that may regulate actin-myosin interactions. The potential roles of tropomyosin, caldesmon, calponin, and SM22 will be discussed. The review, for purposes of brevity, will be nonexhaustive but will give an overview of available information on the in vitro biochemistry and potential in vivo function of these proteins. Preterm labor is discussed as a possible example of where thin filament regulation may be relevant. Considerable controversy surrounds the putative physiological significance of these proteins, and emphasis will be placed on the need for more experimental work to determine the degree to which tissue- and species-specific effects have clouded the interpretation of functional data.
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Affiliation(s)
- K G Morgan
- Signal Transduction Group, Boston Biomedical Research Institute, Watertown 02472, Massachusetts, USA.
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26
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Goto T, Kato N, Ono-Nita SK, Yoshida H, Otsuka M, Shiratori Y, Omata M. Large isoform of hepatitis delta antigen activates serum response factor-associated transcription. J Biol Chem 2000; 275:37311-6. [PMID: 10961986 DOI: 10.1074/jbc.m002947200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hepatitis delta virus infection sometimes causes severe and fulminant hepatitis as a coinfection or superinfection along with the hepatitis B virus. To elucidate the underlying mechanism of injury caused by hepatitis delta virus, we examined whether two isoforms of the hepatitis delta antigen (HDAg) had any effect on five well defined intracellular signal transduction pathways: serum response factor (SRF)-, serum response element (SRE)-, nuclear factor kappaB-, activator protein 1-, and cyclic AMP response element-dependent pathways. Reporter assays revealed that large HDAg (LHDAg) activated the SRF- and SRE-dependent pathways. In contrast, small HDAg (SHDAg) did not activate any of five pathways. LHDAg enhanced the transcriptional ability of SRF without changing its DNA binding affinity in an electrophoretic mobility shift assay. In addition, LHDAg activated a rat SM22alpha promoter containing SRF binding site and a human c-fos promoter containing SRE. In conclusion, LHDAg, but not SHDAg, enhances SRF-associated transcriptions. Despite structural similarities between the two HDAgs, there are significant differences in their effects on intracellular signal transduction pathways. These results may provide clues that will aid in the clarification of functional differences between LHDAg and SHDAg and the pathogenesis of delta hepatitis.
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Affiliation(s)
- T Goto
- Department of Gastroenterology, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
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27
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Fu Y, Liu HW, Forsythe SM, Kogut P, McConville JF, Halayko AJ, Camoretti-Mercado B, Solway J. Mutagenesis analysis of human SM22: characterization of actin binding. J Appl Physiol (1985) 2000; 89:1985-90. [PMID: 11053353 DOI: 10.1152/jappl.2000.89.5.1985] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
SM22 is a 201-amino acid actin-binding protein expressed at high levels in smooth muscle cells. It has structural homology to calponin, but how SM22 binds to actin remains unknown. We performed site-directed mutagenesis to generate a series of NH(2)-terminal histidine (His)-tagged mutants of human SM22 in Escherichia coli and used these to analyze the functional importance of potential actin binding domains. Purified full-length recombinant SM22 bound to actin in vitro, as demonstrated by cosedimentation assay. Binding did not vary with calcium concentration. The COOH-terminal domain of SM22 is required for actin affinity, because COOH terminally truncated mutants [SM22-(1-186) and SM22-(1-166)] exhibited markedly reduced cosedimentation with actin, and no actin binding of SM22-(1-151) could be detected. Internal deletion of a putative actin binding site (154-KKAQEHKR-161) partially prevented actin binding, as did point mutation to neutralize either or both pairs of positively charged residues at the ends of this region (KK154LL and/or KR160LL). Internal deletion of amino acids 170-180 or 170-186 also partially or almost completely inhibited actin cosedimentation, respectively. Of the three consensus protein kinase C or casein kinase II phosphorylation sites in SM22, only Ser-181 was readily phosphorylated by protein kinase C in vitro, and such phosphorylation greatly decreased actin binding. Substitution of Ser-181 to aspartic acid (to mimic serine phosphorylation) also reduced actin binding. Immunostains of transiently transfected airway myocytes revealed that full-length NH(2)-terminal FLAG-tagged SM22 colocalizes with actin filaments, whereas FLAG-SM22-(1-151) does not. These data confirm that SM22 binds to actin in vitro and in vivo and, for the first time, demonstrate that multiple regions within the COOH-terminal domain are required for full actin affinity.
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Affiliation(s)
- Y Fu
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA
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28
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SM22α Promoter Targets Gene Expression to Vascular Smooth Muscle Cells In Vitro and In Vivo. Mol Med 2000. [DOI: 10.1007/bf03401832] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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29
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Ellis PD, Chen Q, Barker PJ, Metcalfe JC, Kemp PR. Nov gene encodes adhesion factor for vascular smooth muscle cells and is dynamically regulated in response to vascular injury. Arterioscler Thromb Vasc Biol 2000; 20:1912-9. [PMID: 10938011 DOI: 10.1161/01.atv.20.8.1912] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Nephroblastoma overexpressed (NOV) is a member of the CCN family (connective tissue growth factor, CYR61, and NOV) of proteins that are involved in regulating the proliferation, differentiation, and adhesion of a variety of cell types. We have examined the expression of the NOV: gene and NOV protein by vascular smooth muscle cells (VSMCs), in vitro and in vivo, and the effects of recombinant NOV on VSMCs. Rat aortic VSMCs were found to express NOV: mRNA and NOV protein in vitro and in vivo. NOV: expression in adult rat tissues was very high in the aorta and was detected only weakly in the brain and lung by Northern analysis (relative levels 33:3:1). During postnatal development (3 days to 12 weeks), the expression of NOV: was correlated with markers of the differentiated smooth muscle cell phenotype (smooth muscle myosin heavy chain and SM22 alpha). In the rat carotid artery balloon injury model, NOV: was detectable by in situ hybridization and was downregulated in the media of the injured artery compared with the uninjured artery at 7 and 14 days after injury. Expression in the developing intima was barely detectable at 7 days after injury except for strong expression at the luminal surface. At 14 days after injury, NOV: expression was substantially increased throughout the intima. In vitro studies of the function of NOV protein showed that it promoted VSMC adhesion via a mechanism that was divalent cation and Arg-Gly-Asp independent but that it did not modulate VSMC proliferation or phenotype. The strong expression and dynamic regulation of NOV: in the arterial wall, together with its ability to promote VSMC adhesion, suggest that it may be involved in homeostasis and repair.
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Affiliation(s)
- P D Ellis
- Section of Cardiovascular Biology, Department of Biochemistry, University of Cambridge, Cambridge, UK.
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30
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Lawson D, Harrison M, Shapland C. Fibroblast transgelin and smooth muscle SM22alpha are the same protein, the expression of which is down-regulated in many cell lines. CELL MOTILITY AND THE CYTOSKELETON 2000; 38:250-7. [PMID: 9384215 DOI: 10.1002/(sici)1097-0169(1997)38:3<250::aid-cm3>3.0.co;2-9] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this report we investigate the expression and relationship of transgelin (Tg), a transformation and shape-change sensitive actin gelling protein found in fibroblasts and smooth muscle [Shapland et al., 1988: J. Cell. Biol. 107:153-161; Shapland et al., 1993: J. Cell. Biol. 121:1065-1073], to SM22alpha, a smooth muscle protein of unknown function [Lees-Millar et al., 1987: J. Biol. Chem. 262:2988-2993; Solway et al., 1995: J. Biol. Chem. 270:13460-13469]. To clarify their relationship we have cloned and sequenced the cDNA encoding Tg from cultures of rat embryo fibroblasts. The sequences of fibroblast Tg and the smooth muscle isoform SM22 are identical [Prinjha et al., 1994: Cell Motil. Cytoskeleton 28:243-255; Shanahan et al., 1993: Circ. Res. 73:193-204; Solway et al., 1995]. These data, coupled with our immunoblot analysis and previous observations [Shapland et al., 1988; Shapland et al., 1993], demonstrate that Tg expression is not restricted to smooth muscle since this protein is also present in normal mesenchymal cells. However, we also show that Tg, although present in secondary cultures of mouse and rat embryo fibroblasts, is absent in many apparently normal fibroblast cell lines. Tg down-regulation may therefore be an early and sensitive marker for the onset of transformation. A functional role for Tg is unlikely to directly involve Ca2+ since it neither contains a functional EF hand nor binds 45Ca2+.
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Affiliation(s)
- D Lawson
- Department of Molecular Pathology, UCL Medical School, Windeyer Institute of Medical Sciences, London, United Kingdom
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31
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Kemp PR, Metcalfe JC. Four isoforms of serum response factor that increase or inhibit smooth-muscle-specific promoter activity. Biochem J 2000; 345 Pt 3:445-51. [PMID: 10642500 PMCID: PMC1220776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Serum response factor (SRF) is a key transcriptional activator of the c-fos gene and of muscle-specific gene expression. We have identified four forms of the SRF coding sequence, SRF-L (the previously identified form), SRF-M, SRF-S and SRF-I, that are produced by alternative splicing. The new forms of SRF lack regions of the C-terminal transactivation domain by splicing out of exon 5 (SRF-M), exons 4 and 5 (SRF-S) and exons 3, 4 and 5 (SRF-I). SRF-M is expressed at similar levels to SRF-L in differentiated vascular smooth-muscle cells and skeletal-muscle cells, whereas SRF-L is the predominant form in many other tissues. SRF-S expression is restricted to vascular smooth muscle and SRF-I expression is restricted to the embryo. Transfection of SRF-L and SRF-M into C(2)C(12) cells showed that both forms are transactivators of the promoter of the smooth-muscle-specific gene SM22alpha, whereas SRF-I acted as a dominant negative form of SRF.
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MESH Headings
- Alternative Splicing
- Animals
- Carcinoma, Embryonal
- Cell Line
- Cloning, Molecular
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Gene Expression Regulation, Developmental
- Mice
- Microfilament Proteins/genetics
- Microfilament Proteins/metabolism
- Muscle Proteins/genetics
- Muscle Proteins/metabolism
- Muscle, Smooth/cytology
- Muscle, Smooth/physiology
- Muscle, Smooth, Vascular/metabolism
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Promoter Regions, Genetic
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- RNA, Messenger/metabolism
- Serum Response Factor
- Tumor Cells, Cultured
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Affiliation(s)
- P R Kemp
- Section of Cardiovascular Biology, Department of Biochemistry, University of Cambridge, The Downing Site, Tennis Court Road, Cambridge CB2 1QW, U.K.
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32
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Martin KM, Cooper WN, Metcalfe JC, Kemp PR. Mouse BTEB3, a new member of the basic transcription element binding protein (BTEB) family, activates expression from GC-rich minimal promoter regions. Biochem J 2000; 345 Pt 3:529-33. [PMID: 10642511 PMCID: PMC1220787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Members of the three-zinc-finger family of transcription factors play an important role in determining basal transcription. We have cloned mouse BTEB3 (mBTEB3), a new member of the basic transcription element binding protein (BTEB) family, which is expressed in a wide variety of tissues. mBTEB3 activates transcription of the simian virus 40 early promoter (4-fold) and of the tissue-specific SM22alpha promoter (100-fold), suggesting that, like BTEB1 and Sp1, mBTEB3 is a basal transcription factor.
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Affiliation(s)
- K M Martin
- Section of Cardiovascular Biology, Department of Biochemistry, Cambridge University, Tennis Court Road, Cambridge CB2 1QW, U.K
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33
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Shanahan CM, Weissberg PL. Smooth muscle cell heterogeneity: patterns of gene expression in vascular smooth muscle cells in vitro and in vivo. Arterioscler Thromb Vasc Biol 1998; 18:333-8. [PMID: 9514400 DOI: 10.1161/01.atv.18.3.333] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Early morphological and biochemical studies indicated that vascular smooth muscle cells (VSMCs) exhibited two distinct phenotypes and that a change from the contractile to the synthetic phenotype was a prerequisite for progression of vascular disease. More recently, it has become evident that these phenotypes probably represent the extremes of a spectrum of phenotypes that may coexist in the vessel wall, which are dictated by their environment and functional requirements and which reflect differing patterns of gene expression. Therefore, knowledge of the key factors that regulate these patterns of gene expression is likely to lead to the ability to manipulate VSMC phenotype. However, before such factors can be identified, the relationship between VSMC gene expression and VSMC phenotype must first be established. We therefore undertook a differential screen of cDNA from VSMCs in vitro to provide a bank of gene markers that could be used under a variety of circumstances to define VSMC phenotype in terms of the pattern of genes expressed. Using this approach, we have found that the pattern of gene expression that occurs during neointima formation in the balloon-injured rat carotid artery is very similar to that seen at a specific period in the developing aorta of the early neonate and is characterized by coexpression of genes for both contractile and matrix proteins. Furthermore, recent studies have shown that VSMCs isolated at different stages of aortic development can stably maintain different phenotypic characteristics in cell culture. The use of these cells in transfection experiments with SM-specific promoter-chloramphenicol acetyltransferase reporter constructs may enable us to determine what regulates the pattern of gene expression in different VSMC phenotypes. Such studies may ultimately lead to the identification of transcription factors responsible for determining VSMC phenotype and may therefore provide targets for therapy aimed at manipulating VSMC gene expression in vascular disease.
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Affiliation(s)
- C M Shanahan
- Department of Medicine, Addenbrooke's Hospital, Cambridge, UK
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Obata H, Hayashi K, Nishida W, Momiyama T, Uchida A, Ochi T, Sobue K. Smooth muscle cell phenotype-dependent transcriptional regulation of the alpha1 integrin gene. J Biol Chem 1997; 272:26643-51. [PMID: 9334246 DOI: 10.1074/jbc.272.42.26643] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The expressional regulation of chicken alpha1 integrin in smooth muscle cells was studied. The alpha1 integrin mRNA was expressed developmentally and was distributed dominantly in vascular and visceral smooth muscles in chick embryos. In a primary culture of smooth muscle cells, alpha1 integrin expression was dramatically down-regulated during serum-induced dedifferentiation. Promoter analyses revealed that the 5'-upstream region (-516 to +281) was sufficient for transcriptional activation in differentiated smooth muscle cells but not in dedifferentiated smooth muscle cells or chick embryo fibroblasts. Like other alpha integrin promoters, the promoter region of the alpha1 integrin gene lacks TATA and CCAAT boxes and contains binding sites for AP1 and AP2. The essential difference from other alpha integrin promoters is the presence of a CArG box-like motif. Deletion and site-directed mutation analyses revealed that the CArG box-like motif was an essential cis-element for transcriptional activation in differentiated smooth muscle cells, whereas the binding sites for AP1 and AP2 were not. Using specific antibodies, a nuclear protein factor specifically bound to the CArG box-like motif was identified as serum response factor. These results indicate that alpha1 integrin expression in smooth muscle cells is regulated transcriptionally in a phenotype-dependent manner and that serum response factor binding plays a crucial role in this regulation.
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Affiliation(s)
- H Obata
- Department of Neurochemistry and Neuropharmacology, Biomedical Research Center, Japan
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35
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Qian J, Kumar A, Szucsik JC, Lessard JL. Tissue and developmental specific expression of murine smooth muscle gamma-actin fusion genes in transgenic mice. Dev Dyn 1996; 207:135-44. [PMID: 8906417 DOI: 10.1002/(sici)1097-0177(199610)207:2<135::aid-aja2>3.0.co;2-i] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Smooth muscle gamma-actin (SMGA) is an excellent marker of smooth muscle differentiation because it is essentially restricted to smooth muscle. As a first step toward unraveling the mechanisms underlying smooth muscle development and differentiation, we have examined the tissue-specific and developmental expression patterns of six constructs carrying portions of the murine SMGA gene linked to chloramphenicol acetyltransferase (CAT) in stable lines of transgenic mice. Based on the transgenic studies most, if not all, of the regulatory elements necessary for proper spatial and temporal expression of SMGA are present within a 13.7 kb segment of the SMGA gene containing 4.9 kb of upstream sequence, exon 1, intron 1, and a portion of exon 2 up to the start codon for translation. A second construct (SMGA11.6CAT) that lacks the distal 2.1 kb of upstream sequence but is otherwise identical to SMGA13.7CAT shows a similar level of smooth muscle-specific CAT activity. However, SMGA9.3CAT fusion gene containing only 571 bp of 5' flanking sequence, but otherwise identical to SMGA13.7CAT, and SMGA6.0CAT containing only the 4.9 kb upstream sequence, exon 1, and a miniintron 1 show a more than a 100-fold reduction of CAT activity in most smooth muscle-rich tissues. Furthermore, removal of most or all of intron 1 from a transgene with 571 bp of upstream sequence (SMGA2.0 CAT and SMGA0.6CAT) results in a near-complete or complete loss of activity, respectively, in all tissues. Overall, the studies suggest that upstream elements between -2.7 kb and -571 bp and elements within intron 1 are required for high levels of SMGA gene expression in an appropriate temporal-spatial fashion.
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Affiliation(s)
- J Qian
- Division of Developmental Biology, Children's Hospital Medical Center, College of Medicine, University of Cincinnati, Ohio 45229-3039, USA
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36
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Moessler H, Mericskay M, Li Z, Nagl S, Paulin D, Small JV. The SM 22 promoter directs tissue-specific expression in arterial but not in venous or visceral smooth muscle cells in transgenic mice. Development 1996; 122:2415-25. [PMID: 8756287 DOI: 10.1242/dev.122.8.2415] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The transcriptional signals underlying smooth muscle differentiation are currently unknown. We report here the complete sequence and characterization of the single mouse gene for the smooth muscle-specific protein SM 22 and the transcriptional activity of its promoter in cultured smooth muscle cells in vitro and in transgenic mice. In the transgenic animals, promoter constructs ranging in length from 445 to 2126 bp directed reporter expression initially in the heart and the somites of embryos and subsequently in the arteries of the vascular system, but in none of the visceral muscles, nor in the veins. Expression in the heart was spatially restricted to the presumptive right ventricle and outflow tract and disappeared in the adult. Likewise, expression in the somites was only transitory and was not observed after about 14.5 days post coitum in the embryo. In the adult mouse, SM 22 promoter activity persisted in the smooth muscle cells of the arteries and was still notably absent from other smooth muscles, despite the ubiquitous presence of the endogenous SM 22 protein. These findings on the transcriptional activity of a smooth muscle promoter in vivo reveal the existence of different differentiation programmes for smooth muscle cells in the veins and the arteries and raise the expectation of a further subdivision of programmes among the visceral muscles.
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Affiliation(s)
- H Moessler
- Institute of Molecular Biology, Austrian Academy of Sciences, Salzburg, Austria
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