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Wehmeier KR, Kurban W, Chandrasekharan C, Onstead-Haas L, Mooradian AD, Haas MJ. Inhibition of ABCA1 Protein Expression and Cholesterol Efflux by TNF α in MLO-Y4 Osteocytes. Calcif Tissue Int 2016; 98:586-95. [PMID: 26759003 DOI: 10.1007/s00223-015-0106-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 12/28/2015] [Indexed: 01/12/2023]
Abstract
Hip fracture and myocardial infarction cause significant morbidity and mortality. In vivo studies raising serum cholesterol levels as well as pro-inflammatory cytokines such as TNF α manifest bone loss and atherosclerotic vascular disease, suggesting that abnormalities of cholesterol transport may contribute to osteoporosis. We used the mouse osteocyte cell line (MLO-Y4) to investigate the effects of TNF α on the expression of cholesterol acceptor proteins such as apolipoprotein A-I (apo A-I) and apolipoprotein E (apo E), as well as on the cholesterol transporters ATP-binding cassette-1 (ABCA1), scavenger receptor class B type 1 (SRB1), and cluster of differentiation 36 (CD36). MLO-Y4 cells do not express apo A-I or apo E; however, they do express all three cholesterol transporters (ABCA1, SRB1, and CD36). Treatment of MLO-Y4 cells with TNF α had no effect on SRB1, CD36, and osteocalcin levels; however, TNF α reduced ABCA1 protein levels in a dose-dependent manner and cholesterol efflux to apo A-I. Interestingly, TNF α treatment increased ABCA1 promoter activity and ABCA1 mRNA levels, and increased liver X receptor α protein expression, but had no effect on retinoid X receptor α and retinoic acid receptor α levels. Pharmacological inhibition of p38 mitogen-activated protein (MAP) kinase, but not c-jun-N-terminal kinase 1 or mitogen-activated protein kinase (MEK), restored ABCA1 protein levels in TNF α-treated cells. These results suggest that pro-inflammatory cytokines regulate cholesterol metabolism in osteocytes in part by suppressing ABCA1 levels post-translationally in a p38 MAP kinase-dependent manner.
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Affiliation(s)
- Kent R Wehmeier
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Florida College of Medicine, 653-1 West 8th Street, L14, Jacksonville, FL, 32209, USA
| | - William Kurban
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Florida College of Medicine, 653-1 West 8th Street, L14, Jacksonville, FL, 32209, USA
| | - Chandrikha Chandrasekharan
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Florida College of Medicine, 653-1 West 8th Street, L14, Jacksonville, FL, 32209, USA
| | - Luisa Onstead-Haas
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Florida College of Medicine, 653-1 West 8th Street, L14, Jacksonville, FL, 32209, USA
| | - Arshag D Mooradian
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Florida College of Medicine, 653-1 West 8th Street, L14, Jacksonville, FL, 32209, USA
| | - Michael J Haas
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Florida College of Medicine, 653-1 West 8th Street, L14, Jacksonville, FL, 32209, USA.
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Kheirollah A, Nagayasu Y, Ueda H, Yokoyama S, Michikawa M, Ito JI. Involvement of cdc42/Rho kinase in ApoA-I-mediated cholesterol efflux through interaction between cytosolic lipid-protein particles and microtubules in rat astrocytes. J Neurosci Res 2014; 92:455-63. [DOI: 10.1002/jnr.23324] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 10/11/2013] [Accepted: 10/15/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Alireza Kheirollah
- Departments of Biochemistry; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
- Cellular and Molecular Research Center; Ahvaz Jundishapur University of Medical Sciences; Iran
| | - Yuko Nagayasu
- Departments of Biochemistry; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
| | - Hiroshi Ueda
- Department of Biomolecular Science; Faculty of Engineering; Gifu University; Gifu Japan
| | - Shinji Yokoyama
- Nutritional Health Science Research Center; Chubu University; Kasugai Japan
| | - Makoto Michikawa
- Departments of Biochemistry; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
| | - Jin-ichi Ito
- Departments of Biochemistry; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
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Loirand G, Sauzeau V, Pacaud P. Small G Proteins in the Cardiovascular System: Physiological and Pathological Aspects. Physiol Rev 2013; 93:1659-720. [DOI: 10.1152/physrev.00021.2012] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Small G proteins exist in eukaryotes from yeast to human and constitute the Ras superfamily comprising more than 100 members. This superfamily is structurally classified into five families: the Ras, Rho, Rab, Arf, and Ran families that control a wide variety of cell and biological functions through highly coordinated regulation processes. Increasing evidence has accumulated to identify small G proteins and their regulators as key players of the cardiovascular physiology that control a large panel of cardiac (heart rhythm, contraction, hypertrophy) and vascular functions (angiogenesis, vascular permeability, vasoconstriction). Indeed, basal Ras protein activity is required for homeostatic functions in physiological conditions, but sustained overactivation of Ras proteins or spatiotemporal dysregulation of Ras signaling pathways has pathological consequences in the cardiovascular system. The primary object of this review is to provide a comprehensive overview of the current progress in our understanding of the role of small G proteins and their regulators in cardiovascular physiology and pathologies.
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Affiliation(s)
- Gervaise Loirand
- INSERM, UMR S1087; University of Nantes; and CHU Nantes, l'Institut du Thorax, Nantes, France
| | - Vincent Sauzeau
- INSERM, UMR S1087; University of Nantes; and CHU Nantes, l'Institut du Thorax, Nantes, France
| | - Pierre Pacaud
- INSERM, UMR S1087; University of Nantes; and CHU Nantes, l'Institut du Thorax, Nantes, France
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