scholarly journals Multiple repressor pathways contribute to phenotypic switching of vascular smooth muscle cells

2007 ◽  
Vol 292 (1) ◽  
pp. C59-C69 ◽  
Author(s):  
Keiko Kawai-Kowase ◽  
Gary K. Owens
Keyword(s):  
Smooth Muscle ◽  
Molecular Mechanisms ◽  
Platelet Derived Growth Factor ◽  
Phenotypic Switching ◽  
Marker Genes ◽  
Environmental Cues ◽  
Selective Marker ◽  
Current State ◽  
Active Repressor

Smooth muscle cell (SMC) differentiation is an essential component of vascular development and these cells perform biosynthetic, proliferative, and contractile roles in the vessel wall. SMCs are not terminally differentiated and possess the ability to modulate their phenotype in response to changing local environmental cues. The focus of this review is to provide an overview of the current state of knowledge of molecular mechanisms involved in controlling phenotypic switching of SMC with particular focus on examination of processes that contribute to the repression of SMC marker genes. We discuss the environmental cues which actively regulate SMC phenotypic switching, such as platelet-derived growth factor-BB, as well as several important regulatory mechanisms required for suppressing expression of SMC-specific/selective marker genes in vivo, including those dependent on conserved G/C-repressive elements, and/or highly conserved degenerate CArG elements found in the promoters of many of these marker genes. Finally, we present evidence indicating that SMC phenotypic switching involves multiple active repressor pathways, including Krüppel-like zinc finger type 4, HERP, and ERK-dependent phosphorylation of Elk-1 that act in a complementary fashion.

scholarly journals Krüppel-like factor 4, Elk-1, and histone deacetylases cooperatively suppress smooth muscle cell differentiation markers in response to oxidized phospholipids

2008 ◽  
Vol 295 (5) ◽  
pp. C1175-C1182 ◽  
Author(s):  
Tadashi Yoshida ◽  
Qiong Gan ◽  
Gary K. Owens
Keyword(s):  
Smooth Muscle ◽  
Histone Deacetylases ◽  
Molecular Mechanisms ◽  
Phenotypic Switching ◽  
Marker Genes ◽  
Physical Interaction ◽  
Oxidized Phospholipids ◽  
Differentiation Markers ◽  
Differentiation Marker

Phenotypic switching of vascular smooth muscle cells (SMCs), such as increased proliferation, enhanced migration, and downregulation of SMC differentiation marker genes, is known to play a key role in the development of atherosclerosis. However, the factors and mechanisms controlling this process are not fully understood. We recently showed that oxidized phospholipids, including 1-palmitoyl-2-(5-oxovaleroyl)- sn-glycero-3-phosphocholine (POVPC), which accumulate in atherosclerotic lesions, are potent repressors of expression of SMC differentiation marker genes in cultured SMCs as well as in rat carotid arteries in vivo. Here, we examined the molecular mechanisms whereby POVPC induces suppression of SMC differentiation marker genes in cultured SMCs. Results showed that POVPC induced phosphorylation of ERK1/2 and Elk-1. The MEK inhibitors U-0126 and PD-98059 attenuated POVPC-induced suppression of smooth muscle ( SM) α-actin and SM-myosin heavy chain. POVPC also induced expression of Krüppel-like factor 4 (Klf4). Chromatin immunoprecipitation assays revealed that POVPC caused simultaneous binding of Elk-1 and Klf4 to the promoter region of the SM α-actin gene. Moreover, coimmunoprecipitation assays showed a physical interaction between Elk-1 and Klf4. Results in Klf4-null SMCs showed that blockade of both Klf4 induction and Elk-1 phosphorylation completely abolished POVPC-induced suppression of SMC differentiation marker genes. POVPC-induced suppression of SMC differentiation marker genes was also accompanied by hypoacetylation of histone H4 at the SM α-actin promoter, which was mediated by the recruitment of histone deacetylases (HDACs), HDAC2 and HDAC5. Coimmunoprecipitation assays showed that Klf4 interacted with HDAC5. Results provide evidence that Klf4, Elk-1, and HDACs coordinately mediate POVPC-induced suppression of SMC differentiation marker genes.

Molecular Regulation of Vascular Smooth Muscle Cell Differentiation in Development and Disease

2004 ◽  
Vol 84 (3) ◽  
pp. 767-801 ◽  
Author(s):  
Gary K. Owens ◽  
Meena S. Kumar ◽  
Brian R. Wamhoff
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Vascular Injury ◽  
Molecular Mechanisms ◽  
Atherosclerotic Lesion ◽  
Cooperative Interaction ◽  
Marker Genes ◽  
Environmental Cues ◽  
Current State ◽  
Wide Range

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.

scholarly journals Platelet-derived growth factor-BB represses smooth muscle cell marker genes via changes in binding of MKL factors and histone deacetylases to their promoters

2007 ◽  
Vol 292 (2) ◽  
pp. C886-C895 ◽  
Author(s):  
Tadashi Yoshida ◽  
Qiong Gan ◽  
Yueting Shang ◽  
Gary K. Owens
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Histone Deacetylases ◽  
Marker Gene ◽  
Platelet Derived Growth Factor ◽  
Phenotypic Switching ◽  
Marker Genes ◽  
Gene Promoters

A hallmark of smooth muscle cell (SMC) phenotypic switching is suppression of SMC marker gene expression. Although myocardin has been shown to be a key regulator of this process, the role of its related factors, MKL1 and MKL2, in SMC phenotypic switching remains unknown. The present studies were aimed at determining if: 1) MKL factors contribute to the expression of SMC marker genes in cultured SMCs; and 2) platelet-derived growth factor-BB (PDGF-BB)-induced repression of SMC marker genes is mediated by suppression of MKL factors. Results of gain- and loss-of-function experiments showed that MKL factors regulated the expression of single and multiple CArG [CC(AT-rich)6GG]-containing SMC marker genes, such as smooth muscle (SM) α-actin and telokin, but not CArG-independent SMC marker genes such as smoothelin-B. Treatment with PDGF-BB reduced the expression of CArG-containing SMC marker genes, as well as myocardin expression in cultured SMCs, while it had no effect on expression of MKL1 and MKL2. However, of interest, PDGF-BB induced the dissociation of MKL factors from the CArG-containing region of SMC marker genes, as determined by chromatin immunoprecipitation assays. This dissociation was caused by the competition between MKL factors and phosphorylated Elk-1 at early time points, but subsequently by the reduction in acetylated histone H4 levels at these promoter regions mediated by histone deacetylases, HDAC2, HDAC4, and HDAC5. Results provide novel evidence that PDGF-BB-induced repression of SMC marker genes is mediated through combinatorial mechanisms, including downregulation of myocardin expression and inhibition of the association of myocardin/MKL factors with CArG-containing SMC marker gene promoters.

Platelet-derived growth factor-BB and Ets-1 transcription factor negatively regulate transcription of multiple smooth muscle cell differentiation marker genes

2004 ◽  
Vol 286 (6) ◽  
pp. H2042-H2051 ◽  
Author(s):  
Frédéric Dandré ◽  
Gary K. Owens
Keyword(s):  
Transcription Factor ◽  
Smooth Muscle ◽  
Growth Factor ◽  
Tyrosine Phosphatase ◽  
Marker Gene ◽  
Platelet Derived Growth Factor ◽  
Phenotypic Switching ◽  
Marker Genes ◽  
Gene Promoters ◽  
Marker Expression

Platelet-derived growth factor (PDGF)-BB, a potent mitogen for mesenchymal cells, also downregulates expression of multiple smooth muscle (SM) cell (SMC)-specific markers. However, there is conflicting evidence whether PDGF-BB represses SMC marker expression at a transcriptional or posttranscriptional level, and little is known regarding the mechanisms responsible for these effects. Results of the present studies provide clear evidence that PDGF-BB treatment strongly repressed SM α-actin, SM myosin heavy chain (MHC), and SM22α promoters in SMCs. Of major significance for resolving previous controversies in the field, we found PDGF-BB-induced repression of SMC marker gene promoters in subconfluent, but not postconfluent, cultures. Treatment of postconfluent SMCs with a tyrosine phosphatase inhibitor restored PDGF-BB-induced repression, whereas treatment of subconfluent SMCs with a tyrosine kinase blocker abolished PDGF-BB-induced repression, suggesting that a tyrosine phosphorylation event mediates cell density-dependent effects. On the basis of previous observations that Ets-1 transcription factor is upregulated within phenotypically modulated neointimal SMCs, we tested whether Ets-1 would repress SMC marker expression. Consistent with this hypothesis, results of cotransfection experiments indicated that Ets-1 overexpression reduced transcriptional activity of SMC marker promoter constructs in SMCs, whereas it increased activity of SM α-actin promoter in endothelial cells. PDGF-BB treatment increased expression of Ets-1 in cultured SMCs, and SM α-actin mRNA expression was reduced in multiple independent clones of SMCs stably transfected with an Ets-1-overexpressing construct. Taken together, results of these experiments provide novel insights regarding possible mechanisms whereby PDGF-BB and Ets-1 may contribute to SMC phenotypic switching associated with vascular injury.

scholarly journals Expression Profile of New Marker Genes Involved in Differentiation of Canine Adipose-Derived Stem Cells into Osteoblasts

2021 ◽  
Vol 22 (13) ◽  
pp. 6663
Author(s):  
Maurycy Jankowski ◽  
Mariusz Kaczmarek ◽  
Grzegorz Wąsiatycz ◽  
Claudia Dompe ◽  
Paul Mozdziak ◽  
...  
Keyword(s):  
Stem Cells ◽  
In Vitro Culture ◽  
Osteogenic Differentiation ◽  
Molecular Mechanisms ◽  
Marker Genes ◽  
P Value ◽  
Illumina Platform

Next-generation sequencing (RNAseq) analysis of gene expression changes during the long-term in vitro culture and osteogenic differentiation of ASCs remains to be important, as the analysis provides important clues toward employing stem cells as a therapeutic intervention. In this study, the cells were isolated from adipose tissue obtained during routine surgical procedures and subjected to 14-day in vitro culture and differentiation. The mRNA transcript levels were evaluated using the Illumina platform, resulting in the detection of 19,856 gene transcripts. The most differentially expressed genes (fold change >|2|, adjusted p value < 0.05), between day 1, day 14 and differentiated cell cultures were extracted and subjected to bioinformatical analysis based on the R programming language. The results of this study provide molecular insight into the processes that occur during long-term in vitro culture and osteogenic differentiation of ASCs, allowing the re-evaluation of the roles of some genes in MSC progression towards a range of lineages. The results improve the knowledge of the molecular mechanisms associated with long-term in vitro culture and differentiation of ASCs, as well as providing a point of reference for potential in vivo and clinical studies regarding these cells’ application in regenerative medicine.

Abstract 149: Pluripotency Factors Krüppel-Like Factor 4 and Octamer-binding Transcription Factor 4 Alter Indices of Plaque Stability in Long Term Western Diet Fed Mice by Regulating Smooth Muscle Cell Phenotypes

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Laura S Shankman ◽  
Olga A Cherepanova ◽  
Delphine Gomez ◽  
Gary K Owens
Keyword(s):  
Smooth Muscle ◽  
Foam Cell ◽  
Lineage Tracing ◽  
Phenotypic Switching ◽  
Marker Genes ◽  
Plaque Stability ◽  
Pluripotency Factors ◽  
Fibrous Cap ◽  
Atherosclerotic Lesions ◽  
Life Threatening

The bulk of life threatening thrombotic events have been associated with disruption of the fibrous cap, an atheroprotective layer of smooth muscle α-actin positive (ACTA2+) cells that form around the plaque, and the presence of a large foam cell-laden necrotic core within the plaque. Despite the overwhelming research demonstrating that ACTA2+ cells are beneficial for plaque stability, and cells positive for macrophage-markers are detrimental, there are major ambiguities regarding the origins of these cells, and their role in lesion stability. To clearly define the contribution of smooth muscle cells (SMCs) within atherosclerotic lesions, we generated SMC specific lineage tracing Apoe-/- mice containing a SM myosin heavy chain ( Myh11 ) tamoxifen-inducible cre-recombinase gene and a floxed STOP ROSA eYFP gene ( Myh11 YFP ApoE-/- mice) thus allowing activation of eYFP exclusively in fully differentiated SMCs before the onset of atherosclerosis and subsequent determination of the fate of these cells and their progeny irrespective of continued expression of MYH11 or other SMC marker genes. Remarkably, our results reveal that 86% of SMCs cannot be identified using traditional SMC markers, such as ACTA2, and 23% of presumed macrophages (LGALS3+ cells) are derived from SMC origins. The last finding was confirmed in human coronary atheromas using the ISH-PLA approach. SMC specific knockout (KO) of the pluripotency factor Klf4 in Myh11 YFP ApoE-/- mice did not alter the frequency of phenotypically modulated (ACTA2-eYFP+) SMCs within atherosclerotic lesions of mice fed a high fat diet for 18 weeks, however, decreased the number of ACTA2-eYFP+ SMCs that expressed LGALS3, and increased several indices of plaque stability, suggesting a detrimental role for KLF4 in SMCs within atherosclerotic lesions. Conversely, SMC specific Oct4 KO resulted in a dramatic reduction in the number of ACTA2-eYFP+ SMCs within the lesion with marked decreases in indices of plaque stability. In summary results show that the majority of SMC-derived cells within advanced atherosclerotic lesions cannot be identified using conventional SMC marker genes, and that phenotypic switching of SMC during atherogenesis is differentially regulated by the pluripotency factors KLF4 and OCT4.

scholarly journals Homodimerization of RBPMS2 through a new RRM-interaction motif is necessary to control smooth muscle plasticity

2014 ◽  
Vol 42 (15) ◽  
pp. 10173-10184 ◽  
Author(s):  
Sébastien Sagnol ◽  
Yinshan Yang ◽  
Yannick Bessin ◽  
Fréderic Allemand ◽  
Ilona Hapkova ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Sequence Motif ◽  
Rna Recognition Motif ◽  
Muscle Plasticity ◽  
Rrm Domain ◽  
Bone Morphogenetic Protein Pathway ◽  
Morphogenetic Protein

Abstract In vertebrates, smooth muscle cells (SMCs) can reversibly switch between contractile and proliferative phenotypes. This involves various molecular mechanisms to reactivate developmental signaling pathways and induce cell dedifferentiation. The protein RBPMS2 regulates early development and plasticity of digestive SMCs by inhibiting the bone morphogenetic protein pathway through its interaction with NOGGIN mRNA. RBPMS2 contains only one RNA recognition motif (RRM) while this motif is often repeated in tandem or associated with other functional domains in RRM-containing proteins. Herein, we show using an extensive combination of structure/function analyses that RBPMS2 homodimerizes through a particular sequence motif (D-x-K-x-R-E-L-Y-L-L-F: residues 39–51) located in its RRM domain. We also show that this specific motif is conserved among its homologs and paralogs in vertebrates and in its insect and worm orthologs (CPO and MEC-8, respectively) suggesting a conserved molecular mechanism of action. Inhibition of the dimerization process through targeting a conserved leucine inside of this motif abolishes the capacity of RBPMS2 to interact with the translational elongation eEF2 protein, to upregulate NOGGIN mRNA in vivo and to drive SMC dedifferentiation. Our study demonstrates that RBPMS2 possesses an RRM domain harboring both RNA-binding and protein-binding properties and that the newly identified RRM-homodimerization motif is crucial for the function of RBPMS2 at the cell and tissue levels.

Role of GADD153 (growth arrest- and DNA damage-inducible gene 153) in vascular smooth muscle cell apoptosis

2001 ◽  
Vol 100 (3) ◽  
pp. 275-281 ◽  
Author(s):  
Michiya IGASE ◽  
Takafumi OKURA ◽  
Michitsugu NAKAMURA ◽  
Yasunori TAKATA ◽  
Yutaka KITAMI ◽  
...  
Keyword(s):  
Dna Damage ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Molecular Mechanisms ◽  
Growth Arrest ◽  
Cell Contact ◽  
Inducible Gene

GADD153 (growth arrest- and DNA damage-inducible gene 153) is expressed at very low levels in growing cells, but is markedly induced in response to a variety of cellular stresses, including glucose deprivation, exposure to genotoxic agents and other growth-arresting situations. Forced expression of GADD153 induces cell cycle arrest in many types of cells. It is also reported that GADD153 is directly associated with apoptosis. Recently we have reported that platelet-derived growth factor (PDGF)-BB induces apoptosis in cultured vascular smooth muscle cells (VSMC), but only when 100% confluency is reached. These results suggested that cell–cell contact inhibition (cell growth arrest) may be a critical factor for induction of VSMC apoptosis by PDGF-BB. In the present study, we explored the role of GADD153, one of a number of growth-arrest-related gene products, in the molecular mechanisms of VSMC apoptosis in vitro and in vivo. GADD153 was markedly induced at both the mRNA and protein levels, in parallel with the induction of VSMC apoptosis, after treatment with PDGF-BB. Moreover, overexpression of GADD153 in VSMC significantly reduced cell viability and induced apoptosis. In the carotid artery balloon injury model in rats, GADD153 protein was expressed in apoptotic VSMC which were positively stained by in situ DNA labelling. These results demonstrate an important role for GADD153 in the molecular mechanisms of VSMC apoptosis.

scholarly journals Galectin-3 is expressed in vascular smooth muscle cells and promotes pulmonary hypertension through changes in proliferation, apoptosis, and fibrosis

2019 ◽  
Vol 316 (5) ◽  
pp. L784-L797 ◽  
Author(s):  
Scott A. Barman ◽  
Xueyi Li ◽  
Stephen Haigh ◽  
Dmitry Kondrikov ◽  
Keyvan Mahboubi ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Molecular Mechanisms ◽  
Muscle Cells ◽  
Cellular Migration ◽  
Rat Models ◽  
Galectin 3 ◽  
Genetic Deletion

A defining characteristic of pulmonary hypertension (PH) is the extensive remodeling of pulmonary arteries (PAs), which results in progressive increases in vascular resistance and stiffness and eventual failure of the right ventricle. There is no cure for PH and identification of novel molecular mechanisms that underlie increased proliferation, reduced apoptosis, and excessive extracellular matrix production in pulmonary artery smooth muscle cells (PASMCs) is a vital objective. Galectin-3 (Gal-3) is a chimeric lectin and potent driver of many aspects of fibrosis, but its role in regulating PASMC behavior in PH remains poorly understood. Herein, we evaluated the importance of increased Gal-3 expression and signaling on PA vascular remodeling and cardiopulmonary function in experimental models of PH. Gal-3 expression was quantified by qRT-PCR, immunoblotting, and immunofluorescence imaging, and its functional role was assessed by specific Gal-3 inhibitors and CRISPR/Cas9-mediated knockout of Gal-3 in the rat. In rat models of PH, we observed increased Gal-3 expression in PASMCs, which stimulated migration and resistance to apoptosis, whereas silencing or genetic deletion reduced cellular migration and PA fibrosis and increased apoptosis. Gal-3 inhibitors attenuated and reversed PA remodeling and fibrosis, as well as hemodynamic indices in monocrotaline (MCT)-treated rats in vivo. These results were supported by genetic deletion of Gal-3 in both MCT and Sugen Hypoxia rat models. In conclusion, our results suggest that elevated Gal-3 levels contribute to inappropriate PA remodeling in PH by enhancing multiple profibrotic mechanisms. Therapeutic strategies targeting Gal-3 may be of benefit in the treatment of PH.

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