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Verschoor PJ, Greig FH, Rochford JJ, Levate G, Delibegovic M, Thompson D, Leeson-Payne A, Dekeryte R, Banks R, Ramos JW, Nixon GF. Phosphoprotein enriched in astrocytes (PEA)-15 is a novel regulator of adipose tissue expansion. Sci Rep 2021; 11:6949. [PMID: 33772049 PMCID: PMC7997924 DOI: 10.1038/s41598-021-86250-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 02/26/2021] [Indexed: 12/17/2022] Open
Abstract
Excessive expansion of adipose tissue in obesity typically leads to overflow and accumulation of lipids in other tissues, causing fatty liver disease and atherosclerosis. The intracellular protein, phosphoprotein enriched in astrocytes (PEA)-15 has been linked to metabolic disease but its role in lipid storage has not been examined. To delineate the role of PEA-15 in adipose tissue, we placed PEA-15−/− mice on a high fat diet. These mice developed increased body weight and greater white adipose tissue expansion compared to high fat diet-fed wild type mice. This was due to increased adipocyte cell size in PEA-15−/− mice consistent with greater lipid storage capacity. Surprisingly, PEA-15−/− mice exhibited improvements in whole body insulin sensitivity, lower hepatic weight and decreased serum triglycerides indicating a protective phenotype. To determine effects on atherosclerosis, PEA-15−/− mice were crossed with the ApoE−/− mice on a high fat diet. Strikingly, these mice were protected from atherosclerosis and had less hepatic lipid accumulation despite increased adiposity. Therefore, we reveal for the first time that PEA-15 plays a novel role in regulating the expansion of adipose tissue. Decreasing PEA-15 expression increases the sequestering of lipids in adipose tissue, protecting other tissues in obesity, thereby improving metabolic health.
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Affiliation(s)
- Pola J Verschoor
- Aberdeen Cardiovascular and Diabetes Centre, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Fiona H Greig
- Aberdeen Cardiovascular and Diabetes Centre, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Justin J Rochford
- Aberdeen Cardiovascular and Diabetes Centre, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK.,Rowett Institute, University of Aberdeen, Aberdeen, UK
| | - Giovanni Levate
- Aberdeen Cardiovascular and Diabetes Centre, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Mirela Delibegovic
- Aberdeen Cardiovascular and Diabetes Centre, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Dawn Thompson
- Aberdeen Cardiovascular and Diabetes Centre, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | | | - Ruta Dekeryte
- Aberdeen Cardiovascular and Diabetes Centre, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Ruth Banks
- Aberdeen Cardiovascular and Diabetes Centre, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Joe W Ramos
- University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, USA
| | - Graeme F Nixon
- Aberdeen Cardiovascular and Diabetes Centre, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK.
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Vastolo V, Nettore IC, Ciccarelli M, Albano L, Raciti GA, Longo M, Beguinot F, Ungaro P. High-fat diet unveils an enhancer element at the Ped/Pea-15 gene responsible for epigenetic memory in skeletal muscle. Metabolism 2018; 87:70-79. [PMID: 29928894 DOI: 10.1016/j.metabol.2018.06.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/09/2018] [Accepted: 06/17/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND The impact of nutrition on the evolution towards type 2 diabetes has recently received increasing attention because of the effect on chromatin structure and gene expression. PURPOSE Evaluate the effect of high-fat diet on chromatin remodelling and expression of Ped/Pea-15, a gene commonly overexpressed in individuals at risk of type 2 diabetes. METHODS We used mouse and cell models to investigate Ped/Pea-15 transcriptional regulation by high-fat diet and glucose, respectively. Chromatin structure and histone modification marks were assessed by Micrococcal Nuclease Protection and Chromatin Immunoprecipitation assays. RESULTS Sixteen-week exposure of C57BL/6J mice to a high-fat diet impaired glucose tolerance and enhanced Ped/Pea-15 expression in their skeletal muscle tissue. This effect was associated with increased chromatin accessibility at specific regulatory sites at the Ped/Pea-15 gene. In particular, the region at -1900 to -1300 bp from Ped/Pea-15 transcription start site was revealed to feature enhancer activity as demonstrated by its function in the luciferase assay, increased p300 recruitment and H3K4me1 and H3K27Ac levels, all marks of functionally active enhancers. Returning mice to a standard chow diet was accompanied by rapid loss of acetylation of K27 on histone H3 and p300 recruitment at Ped/Pea-15. In contrast, the increased H3K4me1, which accompanied the high-fat diet exposure, remained stable. Incubation of muscle cells in culture medium supplemented with 25 mM glucose (HG) increased Ped/Pea-15 mRNA expression and H3K4me1 at the enhancer region. These effects became measurable upon 72 h of exposure to the HG medium and were not rescued upon returning the cells to the 5 mM glucose-containing medium. Interestingly, after 25 mM and sequential 5 mM glucose treatments, re-exposure of the same cells to HG medium further enhanced Ped/Pea-15 expression and increased H3K4me1 above the levels induced by the initial HG challenge already upon 24 h. CONCLUSION Transient exposure to HFD or HG unveiled the presence of an enhancer element at the Ped/Pea-15 gene. Epigenetic changes imposed at this region by diets, which impair glucose tolerance generate metabolic memory of the nutritional injury and leave Ped/Pea-15 induction in a poised state.
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Affiliation(s)
- Viviana Vastolo
- URT Genomics of Diabetes-IEOS, CNR/Department of Translational Medicine, "Federico II" University Medical School of Napoli, via Sergio Pansini 5, 80131 Naples, Italy
| | - Immacolata Cristina Nettore
- Dipartimento di Medicina Clinica e Chirurgia, Unit of Endocrinology, "Federico II" University Medical School of Napoli, via Sergio Pansini 5, 80131 Naples, Italy
| | - Marco Ciccarelli
- URT Genomics of Diabetes-IEOS, CNR/Department of Translational Medicine, "Federico II" University Medical School of Napoli, via Sergio Pansini 5, 80131 Naples, Italy
| | - Luigi Albano
- URT Genomics of Diabetes-IEOS, CNR/Department of Translational Medicine, "Federico II" University Medical School of Napoli, via Sergio Pansini 5, 80131 Naples, Italy
| | - Gregory Alexander Raciti
- URT Genomics of Diabetes-IEOS, CNR/Department of Translational Medicine, "Federico II" University Medical School of Napoli, via Sergio Pansini 5, 80131 Naples, Italy
| | - Michele Longo
- URT Genomics of Diabetes-IEOS, CNR/Department of Translational Medicine, "Federico II" University Medical School of Napoli, via Sergio Pansini 5, 80131 Naples, Italy
| | - Francesco Beguinot
- URT Genomics of Diabetes-IEOS, CNR/Department of Translational Medicine, "Federico II" University Medical School of Napoli, via Sergio Pansini 5, 80131 Naples, Italy.
| | - Paola Ungaro
- URT Genomics of Diabetes-IEOS, CNR/Department of Translational Medicine, "Federico II" University Medical School of Napoli, via Sergio Pansini 5, 80131 Naples, Italy.
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3
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Wheaton K, Aten S, Queiroz LS, Sullivan K, Oberdick J, Hoyt KR, Obrietan K. Circadian expression and functional characterization of PEA-15 within the mouse suprachiasmatic nucleus. Eur J Neurosci 2018; 47:845-857. [PMID: 29383758 DOI: 10.1111/ejn.13850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/15/2017] [Accepted: 01/15/2018] [Indexed: 12/14/2022]
Abstract
The circadian timing system influences the functional properties of most, if not all, physiological processes. Central to the mammalian timing system is the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN functions as a 'master clock' that sets the phasing of ancillary circadian oscillator populations found throughout the body. Further, via an entraining input from the retina, the SCN ensures that the clock oscillators are synchronized to the daily light/dark cycle. A critical component of the SCN timing and entrainment systems is the p44/42 mitogen-activated protein kinase (ERK/MAPK) pathway. Here, we examined the expression and function of phosphoprotein-enriched in astrocytes (PEA-15), an ERK scaffold protein that serves as a key regulator of MAPK signaling. A combination of immunolabeling and Western blotting approaches revealed high levels of PEA-15 within the SCN. PEA-15 expression was enriched in distinct subpopulations of SCN neurons, including arginine vasopressin (AVP)-positive neurons of the SCN shell region. Further, expression profiling detected a significant circadian oscillation in PEA-15 expression within the SCN. Brief photic stimulation during the early subjective night led to a significant increase in PEA-15 phosphorylation, an event that can trigger ERK/PEA-15 dissociation. Consistent with this, co-immunoprecipitation assays revealed that PEA-15 is directly bound to ERK in the SCN and that photic stimulation leads to their dissociation. Finally, we show that PEA-15 regulates ERK/MAPK-dependent activation of the core clock gene period1. Together, these data raise the prospect that PEA-15 functions as a key regulator of the SCN timing system.
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Affiliation(s)
- Kelin Wheaton
- Division of Pharmacology, Ohio State University, Columbus, OH, 43210, USA
| | - Sydney Aten
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
| | | | - Kyle Sullivan
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
| | - John Oberdick
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
| | - Kari R Hoyt
- Division of Pharmacology, Ohio State University, Columbus, OH, 43210, USA
| | - Karl Obrietan
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
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4
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Greig FH, Kennedy S, Gibson G, Ramos JW, Nixon GF. PEA-15 (Phosphoprotein Enriched in Astrocytes 15) Is a Protective Mediator in the Vasculature and Is Regulated During Neointimal Hyperplasia. J Am Heart Assoc 2017; 6:JAHA.117.006936. [PMID: 28893763 PMCID: PMC5634313 DOI: 10.1161/jaha.117.006936] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Neointimal hyperplasia following angioplasty occurs via vascular smooth muscle cell proliferation. The mechanisms involved are not fully understood but include mitogen-activated protein kinases ERK1/2 (extracellular signal-regulated kinases 1 and 2). We recently identified the intracellular mediator PEA-15 (phosphoprotein enriched in astrocytes 15) in vascular smooth muscle cells as a regulator of ERK1/2-dependent proliferation in vitro. PEA-15 acts as a cytoplasmic anchor for ERK1/2, preventing nuclear localization and thereby reducing ERK1/2-dependent gene expression. The aim of the current study was to examine the role of PEA-15 in neointimal hyperplasia in vivo. METHOD AND RESULTS Mice deficient in PEA-15 or wild-type mice were subjected to wire injury of the carotid artery. In uninjured arteries from PEA-15-deficient mice, ERK1/2 had increased nuclear translocation and increased basal ERK1/2-dependent transcription. Following wire injury, arteries from PEA-15-deficient mice developed neointimal hyperplasia at an increased rate compared with wild-type mice. This occurred in parallel with an increase in a proliferative marker and vascular smooth muscle cell proliferation. In wild-type mice, PEA-15 expression was decreased in vascular smooth muscle cells at an early stage before any increase in intima:media ratio. This regulation of PEA-15 expression following injury was also observed in an ex vivo human model of hyperplasia. CONCLUSIONS These results indicate, for the first time, a novel protective role for PEA-15 against inappropriate vascular proliferation. PEA-15 expression may also be repressed during vascular injury, suggesting that maintenance of PEA-15 expression is a novel therapeutic target in vascular disease.
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Affiliation(s)
- Fiona H Greig
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, United Kingdom
| | - Simon Kennedy
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, United Kingdom
| | - George Gibson
- Department of Cardiothoracic Surgery, Aberdeen Royal Hospital, Aberdeen, United Kingdom
| | - Joe W Ramos
- Cancer Biology Program, University of Hawaii Cancer Centre University of Hawaii at Mānoa, Honolulu, HI
| | - Graeme F Nixon
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, United Kingdom
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5
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Jiang D, Zhuang J, Peng W, Lu Y, Liu H, Zhao Q, Chi C, Li X, Zhu G, Xu X, Yan C, Xu Y, Ge J, Pang J. Phospholipase Cγ1 Mediates Intima Formation Through Akt-Notch1 Signaling Independent of the Phospholipase Activity. J Am Heart Assoc 2017; 6:JAHA.117.005537. [PMID: 28698260 PMCID: PMC5586285 DOI: 10.1161/jaha.117.005537] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Background Vascular smooth muscle cell proliferation, migration, and dedifferentiation are critical for vascular diseases. Recently, it was demonstrated that Notch receptors have opposing effects on intima formation after vessel injury. Therefore, it is important to investigate the specific regulatory pathways that activate the different Notch receptors. Methods and Results There was a time‐ and dose‐dependent activation of Notch1 by angiotensin II and platelet‐derived growth factor in vascular smooth muscle cells. When phospholipase Cγ1 (PLCγ1) expression was reduced by small interfering RNA, Notch1 activation and Hey2 expression (Notch target gene) induced by angiotensin II or platelet‐derived growth factor were remarkably inhibited, while Notch2 degradation was not affected. Mechanistically, we observed an association of PLCγ1 and Akt, which increased after angiotensin II or platelet‐derived growth factor stimulation. PLCγ1 knockdown significantly inhibited Akt activation. Importantly, PLCγ1 phospholipase site mutation (no phospholipase activity) did not affect Akt activation. Furthermore, PLCγ1 depletion inhibited platelet‐derived growth factor–induced vascular smooth muscle cell proliferation, migration, and dedifferentiation, while it increased apoptosis. In vivo, PLCγ1 and control small interfering RNA were delivered periadventitially in pluronic gel and complete carotid artery ligation was performed. Morphometric analysis 21 days after ligation demonstrated that PLCγ1 small interfering RNA robustly attenuated intima area and intima/media ratio compared with the control group. Conclusions PLCγ1‐Akt–mediated Notch1 signaling is crucial for intima formation. This effect is attributable to PLCγ1‐Akt interaction but not PLCγ1 phospholipase activity. Specific inhibition of the PLCγ1 and Akt interaction will be a promising therapeutic strategy for preventing vascular remodeling.
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Affiliation(s)
- Dongyang Jiang
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jianhui Zhuang
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Wenhui Peng
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yuyan Lu
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Hao Liu
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Qian Zhao
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Chen Chi
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiankai Li
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Guofu Zhu
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiangbin Xu
- Aab Cardiovascular Research Institute and Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Chen Yan
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.,Aab Cardiovascular Research Institute and Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Yawei Xu
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Junbo Ge
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jinjiang Pang
- Department of Cardiology, Pan-Vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China .,Aab Cardiovascular Research Institute and Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY
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6
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Staats KA, Humblet-Baron S, Bento-Abreu A, Scheveneels W, Nikolaou A, Deckers K, Lemmens R, Goris A, Van Ginderachter JA, Van Damme P, Hisatsune C, Mikoshiba K, Liston A, Robberecht W, Van Den Bosch L. Genetic ablation of IP3 receptor 2 increases cytokines and decreases survival of SOD1G93A mice. Hum Mol Genet 2016; 25:3491-3499. [PMID: 27378687 PMCID: PMC5179944 DOI: 10.1093/hmg/ddw190] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 06/08/2016] [Accepted: 06/10/2016] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating progressive neurodegenerative disease characterized by the selective death of motor neurons. Disease pathophysiology is complex and not yet fully understood. Higher gene expression of the inositol 1,4,5-trisphosphate receptor 2 gene (ITPR2), encoding the IP3 receptor 2 (IP3R2), was detected in sporadic ALS patients. Here, we demonstrate that IP3R2 gene expression was also increased in spinal cords of ALS mice. Moreover, an increase of IP3R2 expression was observed in other models of chronic and acute neurodegeneration. Upregulation of IP3R2 gene expression could be induced by lipopolysaccharide (LPS) in murine astrocytes, murine macrophages and human fibroblasts indicating that it may be a compensatory response to inflammation. Preventing this response by genetic deletion of ITPR2 from SOD1G93A mice had a dose-dependent effect on disease duration, resulting in a significantly shorter lifespan of these mice. In addition, the absence of IP3R2 led to increased innate immunity, which may contribute to the decreased survival of the SOD1G93A mice. Besides systemic inflammation, IP3R2 knockout mice also had increased IFNγ, IL-6 and IL1α expression. Altogether, our data indicate that IP3R2 protects against the negative effects of inflammation, suggesting that the increase in IP3R2 expression in ALS patients is a protective response.
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Affiliation(s)
- Kim A Staats
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Research Institute for Neuroscience and Disease (LIND).,VIB, Vesalius Research Center, Laboratory of Neurobiology
| | | | - Andre Bento-Abreu
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Research Institute for Neuroscience and Disease (LIND).,VIB, Vesalius Research Center, Laboratory of Neurobiology
| | - Wendy Scheveneels
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Research Institute for Neuroscience and Disease (LIND).,VIB, Vesalius Research Center, Laboratory of Neurobiology
| | - Alexandros Nikolaou
- Molecular and Biochemical Pharmacology Laboratory, Vrije Universiteit Brussel.,Myeloid Cell Immunology Laboratory, VIB, Inflammation Research Center.,Cellular and Molecular Immunology Unit, Vrije Universiteit Brussel, Brussels, Belgium
| | - Kato Deckers
- Center for Molecular and Vascular Biology, University of Leuven
| | - Robin Lemmens
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Research Institute for Neuroscience and Disease (LIND).,VIB, Vesalius Research Center, Laboratory of Neurobiology.,University Hospitals Leuven, Department of Neurology
| | - An Goris
- KU Leuven - University of Leuven, Department of Neurosciences, Laboratory for Neuroimmunology, Leuven, Belgium
| | - Jo A Van Ginderachter
- Myeloid Cell Immunology Laboratory, VIB, Inflammation Research Center.,Cellular and Molecular Immunology Unit, Vrije Universiteit Brussel, Brussels, Belgium
| | - Philip Van Damme
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Research Institute for Neuroscience and Disease (LIND).,VIB, Vesalius Research Center, Laboratory of Neurobiology.,University Hospitals Leuven, Department of Neurology
| | - Chihiro Hisatsune
- Laboratory for Developmental Neurobiology, Brain Science Institute, RIKEN, Wako-shi, Saitama, Japan
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, Brain Science Institute, RIKEN, Wako-shi, Saitama, Japan
| | - Adrian Liston
- VIB and Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium
| | - Wim Robberecht
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Research Institute for Neuroscience and Disease (LIND).,VIB, Vesalius Research Center, Laboratory of Neurobiology.,University Hospitals Leuven, Department of Neurology
| | - Ludo Van Den Bosch
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Research Institute for Neuroscience and Disease (LIND) .,VIB, Vesalius Research Center, Laboratory of Neurobiology
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McKean JS, Murray F, Gibson G, Shewan DA, Tucker SJ, Nixon GF. The cAMP-producing agonist beraprost inhibits human vascular smooth muscle cell migration via exchange protein directly activated by cAMP. Cardiovasc Res 2015; 107:546-55. [PMID: 26092100 PMCID: PMC4540143 DOI: 10.1093/cvr/cvv176] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 06/12/2015] [Indexed: 02/05/2023] Open
Abstract
Aims During restenosis, vascular smooth muscle cells (VSMCs) migrate from the vascular media to the developing neointima. Preventing VSMC migration is therefore a therapeutic target for restenosis. Drugs, such as prostacyclin analogues, that increase the intracellular concentration of cyclic adenosine monophosphate (cAMP) can inhibit VSMC migration, but the mechanisms via which this occurs are unknown. Two main downstream mediators of cAMP are protein kinase A (PKA) and exchange protein directly activated by cAMP (Epac). This study has examined the effects of the prostacyclin analogue beraprost on VSMC migration and investigated the intracellular pathways involved. Methods and results In a chemotaxis chamber, human saphenous vein VSMC migrated towards a platelet-derived growth-factor-BB (PDGF) chemogradient. Incubation with therapeutically relevant concentrations of cAMP-producing agonist beraprost significantly decreased PDGF-induced migration. Direct activation of either PKA or Epac inhibited migration whereas inhibition of PKA did not prevent the anti-migratory effect of beraprost. Direct activation of Epac also prevented hyperplasia in ex vivo serum-treated human veins. Using fluorescence resonance energy transfer, we demonstrated that beraprost activated Epac but not PKA. The mechanisms of this Epac-mediated effect involved activation of Rap1 with subsequent inhibition of RhoA. Cytoskeletal rearrangement at the leading edge of the cell was consequently inhibited. Interestingly, Epac1 was localized to the leading edge of migrating VSMC. Conclusions These results indicate that therapeutically relevant concentrations of beraprost can inhibit VSMC migration via a previously unknown mechanism involving the cAMP mediator Epac. This may provide a novel target that could blunt neointimal formation.
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Affiliation(s)
- Jenny S McKean
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Fiona Murray
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - George Gibson
- Department of Cardiothoracic Surgery, Aberdeen Royal Infirmary, Aberdeen, UK
| | - Derryck A Shewan
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Steven J Tucker
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Graeme F Nixon
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
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8
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Xiao J, Chen X, Xu L, Zhang Y, Yin Q, Wang F. PDGF regulates chondrocyte proliferation through activation of the GIT1- and PLCγ1-mediated ERK1/2 signaling pathway. Mol Med Rep 2014; 10:2409-14. [PMID: 25175053 DOI: 10.3892/mmr.2014.2506] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 03/17/2014] [Indexed: 11/06/2022] Open
Abstract
Studies investigating the effects of cytokines on chondrocytes have significant application potential, since the culture of cartilage cells in vitro is a vital step for cartilage tissue engineering. Platelet-derived growth factor (PDGF), one of the growth factors occurring at the early stage of the healing process of damaged tissue, is critical in bone healing. The present study investigated the effects of the activation of PDGF on cell proliferation, apoptosis and the underlying mechanisms of chondrocytes in vitro. The results indicated that the stimulation of PDGF led to overexpression of the G-protein-coupled receptor kinase interacting protein-1 (GIT1) and promotion of the phosphorylation of phospholipase Cγ1 (PLCγ1). Furthermore, PDGF induced chondrocyte proliferation and inhibited apoptosis via activation of the extracellular signal-regulated kinase (ERK) 1/2 pathway. Following knocking down GIT1 expression by small interfering RNA, phosphorylation of PLCγ1 and activation of the ERK1/2 pathway was no longer promoted by PDGF. In addition, the effects of PDGF on proliferation and apoptosis were suppressed. The expression levels of GIT1 were not affected; however, the phosphorylation of ERK1/2 was suppressed through inhibition of the phosphorylation of PLCγ1 by U73122. The results demonstrated that GIT1 is upstream of PLCγ1. Although the ability of PDGF to induce cell proliferation was inhibited by the inhibition of the ERK1/2 pathway by PD98059, apoptosis was not suppressed. In conclusion, the present study demonstrated that PDGF was able to activate the GIT1‑PLCγ1‑mediated ERK1/2 pathway to control chondrocyte proliferation.
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Affiliation(s)
- Jin Xiao
- Department of Orthopedics, Liuhuaqiao Hospital, Guangzhou, Guangdong 510010, P.R. China
| | - Xuqiong Chen
- Department of Orthopedics, Liuhuaqiao Hospital, Guangzhou, Guangdong 510010, P.R. China
| | - Lipeng Xu
- Department of Orthopedics, Liuhuaqiao Hospital, Guangzhou, Guangdong 510010, P.R. China
| | - Ying Zhang
- Department of Orthopedics, Liuhuaqiao Hospital, Guangzhou, Guangdong 510010, P.R. China
| | - Qingshui Yin
- Department of Orthopedics, Liuhuaqiao Hospital, Guangzhou, Guangdong 510010, P.R. China
| | - Fei Wang
- Department of Orthopedics, Liuhuaqiao Hospital, Guangzhou, Guangdong 510010, P.R. China
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9
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Greig FH, Nixon GF. Phosphoprotein enriched in astrocytes (PEA)-15: a potential therapeutic target in multiple disease states. Pharmacol Ther 2014; 143:265-74. [PMID: 24657708 PMCID: PMC4127788 DOI: 10.1016/j.pharmthera.2014.03.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Phosphoprotein enriched in astrocytes-15 (PEA-15) is a cytoplasmic protein that sits at an important junction in intracellular signalling and can regulate diverse cellular processes, such as proliferation and apoptosis, dependent upon stimulation. Regulation of these processes occurs by virtue of the unique interaction of PEA-15 with other signalling proteins. PEA-15 acts as a cytoplasmic tether for the mitogen-activated protein kinases, extracellular signal-regulated kinase 1/2 (ERK1/2) preventing nuclear localisation. In order to release ERK1/2, PEA-15 requires to be phosphorylated via several potential pathways. PEA-15 (and its phosphorylation state) therefore regulates many ERK1/2-dependent processes, including proliferation, via regulating ERK1/2 nuclear translocation. In addition, PEA-15 contains a death effector domain (DED) which allows interaction with other DED-containing proteins. PEA-15 can bind the DED-containing apoptotic adaptor molecule, Fas-associated death domain protein (FADD) which is also dependent on the phosphorylation status of PEA-15. PEA-15 binding of FADD can inhibit apoptosis as bound FADD cannot participate in the assembly of apoptotic signalling complexes. Through these protein–protein interactions, PEA-15-regulated cellular effects have now been investigated in a number of disease-related studies. Changes in PEA-15 expression and regulation have been observed in diabetes mellitus, cancer, neurological disorders and the cardiovascular system. These changes have been suggested to contribute to the pathology related to each of these disease states. As such, new therapeutic targets based around PEA-15 and its associated interactions are now being uncovered and could provide novel avenues for treatment strategies in multiple diseases.
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Affiliation(s)
- Fiona H Greig
- School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Graeme F Nixon
- School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
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Allen-Redpath K, Ou O, Beattie JH, Kwun IS, Feldmann J, Nixon GF. Marginal dietary zinc deficiency in vivo induces vascular smooth muscle cell apoptosis in large arteries. Cardiovasc Res 2013; 99:525-34. [DOI: 10.1093/cvr/cvt114] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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11
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Current world literature. Lipid metabolism. Curr Opin Lipidol 2012; 23:248-254. [PMID: 22576583 DOI: 10.1097/mol.0b013e3283543033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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12
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Vetterkind S, Saphirstein RJ, Morgan KG. Stimulus-specific activation and actin dependency of distinct, spatially separated ERK1/2 fractions in A7r5 smooth muscle cells. PLoS One 2012; 7:e30409. [PMID: 22363435 PMCID: PMC3283592 DOI: 10.1371/journal.pone.0030409] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 12/15/2011] [Indexed: 12/16/2022] Open
Abstract
A proliferative response of smooth muscle cells to activation of extracellular signal regulated kinases 1 and 2 (ERK1/2) has been linked to cardiovascular disease. In fully differentiated smooth muscle, however, ERK1/2 activation can also regulate contraction. Here, we use A7r5 smooth muscle cells, stimulated with 12-deoxyphorbol 13-isobutylate 20-acetate (DPBA) to induce cytoskeletal remodeling or fetal calf serum (FCS) to induce proliferation, to identify factors that determine the outcomes of ERK1/2 activation in smooth muscle. Knock down experiments, immunoprecipitation and proximity ligation assays show that the ERK1/2 scaffold caveolin-1 mediates ERK1/2 activation in response to DPBA, but not FCS, and that ERK1/2 is released from caveolin-1 upon DPBA, but not FCS, stimulation. Conversely, ERK1/2 associated with the actin cytoskeleton is significantly reduced after FCS, but not DPBA stimulation, as determined by Triton X fractionation. Furthermore, cytochalasin treatment inhibits DPBA, but not FCS-induced ERK1/2 phosphorylation, indicating that the actin cytoskeleton is not only a target but also is required for ERK1/2 activation. Our results show that (1) at least two ERK1/2 fractions are regulated separately by specific stimuli, and that (2) the association of ERK1/2 with the actin cytoskeleton regulates the outcome of ERK1/2 signaling.
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Affiliation(s)
- Susanne Vetterkind
- Department of Health Sciences, Boston University, Boston, Massachusetts, United States of America.
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