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Schweitzer GG, Collier SL, Chen Z, McCommis KS, Pittman SK, Yoshino J, Matkovich SJ, Hsu FF, Chrast R, Eaton JM, Harris TE, Weihl CC, Finck BN. Loss of lipin 1-mediated phosphatidic acid phosphohydrolase activity in muscle leads to skeletal myopathy in mice. FASEB J 2018; 33:652-667. [PMID: 30028636 DOI: 10.1096/fj.201800361r] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Lipin 1 regulates glycerolipid homeostasis by acting as a phosphatidic acid phosphohydrolase (PAP) enzyme in the triglyceride-synthesis pathway and by regulating transcription factor activity. Mutations in human lipin 1 are a common cause of recurrent rhabdomyolysis in children. Mice with constitutive whole-body lipin 1 deficiency have been used to examine mechanisms connecting lipin 1 deficiency to myocyte injury. However, that mouse model is confounded by lipodystrophy not phenocopied in people. Herein, 2 muscle-specific mouse models were studied: 1) Lpin1 exon 3 and 4 deletion, resulting in a hypomorphic protein without PAP activity, but which preserved transcriptional coregulatory function; and 2) Lpin1 exon 7 deletion, resulting in total protein loss. In both models, skeletal muscles exhibited a chronic myopathy with ongoing muscle fiber necrosis and regeneration and accumulation of phosphatidic acid and, paradoxically, diacylglycerol. Additionally, lipin 1-deficient mice had abundant, but abnormal, mitochondria likely because of impaired autophagy. Finally, these mice exhibited increased plasma creatine kinase following exhaustive exercise when unfed. These data suggest that mice lacking lipin 1-mediated PAP activity in skeletal muscle may serve as a model for determining the mechanisms by which lipin 1 deficiency leads to myocyte injury and for testing potential therapeutic approaches.-Schweitzer, G. G., Collier, S. L., Chen, Z., McCommis, K. S., Pittman, S. K., Yoshino, J., Matkovich, S. J., Hsu, F.-F., Chrast, R., Eaton, J. M., Harris, T. E., Weihl, C. C., Finck, B. N. Loss of lipin 1-mediated phosphatidic acid phosphohydrolase activity in muscle leads to skeletal myopathy in mice.
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Affiliation(s)
- George G Schweitzer
- Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sara L Collier
- Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Zhouji Chen
- Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Kyle S McCommis
- Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sara K Pittman
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jun Yoshino
- Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Scot J Matkovich
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Fong-Fu Hsu
- Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Roman Chrast
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; and.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; and
| | - James M Eaton
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Conrad C Weihl
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Brian N Finck
- Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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Soufi N, Hall AM, Chen Z, Yoshino J, Collier SL, Mathews JC, Brunt EM, Albert CJ, Graham MJ, Ford DA, Finck BN. Inhibiting monoacylglycerol acyltransferase 1 ameliorates hepatic metabolic abnormalities but not inflammation and injury in mice. J Biol Chem 2014; 289:30177-88. [PMID: 25213859 DOI: 10.1074/jbc.m114.595850] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Abnormalities in hepatic lipid metabolism and insulin action are believed to play a critical role in the etiology of nonalcoholic steatohepatitis. Monoacylglycerol acyltransferase (MGAT) enzymes convert monoacylglycerol to diacylglycerol, which is the penultimate step in one pathway for triacylglycerol synthesis. Hepatic expression of Mogat1, which encodes an MGAT enzyme, is increased in the livers of mice with hepatic steatosis, and knocking down Mogat1 improves glucose metabolism and hepatic insulin signaling, but whether increased MGAT activity plays a role in the etiology of nonalcoholic steatohepatitis is unclear. To examine this issue, mice were placed on a diet containing high levels of trans fatty acids, fructose, and cholesterol (HTF-C diet) or a low fat control diet for 4 weeks. Mice were injected with antisense oligonucleotides (ASOs) to knockdown Mogat1 or a scrambled ASO control for 12 weeks while remaining on diet. The HTF-C diet caused glucose intolerance, hepatic steatosis, and induced hepatic gene expression markers of inflammation, macrophage infiltration, and stellate cell activation. Mogat1 ASO treatment, which suppressed Mogat1 expression in liver and adipose tissue, attenuated weight gain, improved glucose tolerance, improved hepatic insulin signaling, and decreased hepatic triacylglycerol content compared with control ASO-treated mice on HTF-C chow. However, Mogat1 ASO treatment did not reduce hepatic diacylglycerol, cholesterol, or free fatty acid content; improve histologic measures of liver injury; or reduce expression of markers of stellate cell activation, liver inflammation, and injury. In conclusion, inhibition of hepatic Mogat1 in HTF-C diet-fed mice improves hepatic metabolic abnormalities without attenuating liver inflammation and injury.
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Affiliation(s)
| | | | | | | | | | - James C Mathews
- Pathology and Immunology, Washington University School of Medicine, Saint Louis, Missouri 63110
| | - Elizabeth M Brunt
- Pathology and Immunology, Washington University School of Medicine, Saint Louis, Missouri 63110
| | - Carolyn J Albert
- the Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri 63104, and
| | - Mark J Graham
- ISIS Pharmaceuticals Inc., Carlsbad, California 92008
| | - David A Ford
- the Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri 63104, and
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Colleran PN, Tanner MA, Latcham SL, Collier SL, Laughlin MH, McAllister RM, Price EM. The role of nitric oxide synthase in exercise induced changes in endothelial progenitor cell number. FASEB J 2006. [DOI: 10.1096/fasebj.20.4.a750-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Patrick Nicholas Colleran
- Dalton Cardiovascular Research Center and Department of Biomedical ScienceUniversity of Missouri1600 E. RollinsColumbiaMissouri65211
| | - Miles A. Tanner
- Dalton Cardiovascular Research Center and Department of Biomedical ScienceUniversity of Missouri1600 E. RollinsColumbiaMissouri65211
| | - Shena L. Latcham
- Dalton Cardiovascular Research Center and Department of Biomedical ScienceUniversity of Missouri1600 E. RollinsColumbiaMissouri65211
| | - Sara L. Collier
- Dalton Cardiovascular Research Center and Department of Biomedical ScienceUniversity of Missouri1600 E. RollinsColumbiaMissouri65211
| | - M. Harold Laughlin
- Dalton Cardiovascular Research Center and Department of Biomedical ScienceUniversity of Missouri1600 E. RollinsColumbiaMissouri65211
| | - Richard M. McAllister
- Dalton Cardiovascular Research Center and Department of Biomedical ScienceUniversity of Missouri1600 E. RollinsColumbiaMissouri65211
| | - Elmer M. Price
- Dalton Cardiovascular Research Center and Department of Biomedical ScienceUniversity of Missouri1600 E. RollinsColumbiaMissouri65211
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Collier SL, Wilson DK. Performance bounds for passive sensor arrays operating in a turbulent medium: plane-wave analysis. J Acoust Soc Am 2003; 113:2704-2718. [PMID: 12765389 DOI: 10.1121/1.1554691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The performance bounds of a passive acoustic array operating in a turbulent medium with fluctuations described by a von Kármán spectrum are investigated. This treatment considers a single, monochromatic, plane-wave source at near-normal incidence. A line-of-sight propagation path is assumed. The primary interests are in calculating the Cramer-Rao lower bounds of the azimuthal and elevational angles of arrival and in observing how these bounds change with the introduction of additional unknowns, such as the propagation distance, turbulence parameters, and signal-to-noise ratio. In both two and three dimensions, it is found that for large values of the index-of-refraction variance, the Cramer-Rao lower bounds of the angles of arrival increase significantly at large values of the normalized propagation distance. For small values of the index-of-refraction variance and normalized propagation distance, the signal-to-noise ratio is found to be the limiting factor. In the two-dimensional treatment, it is found that the estimate of the angle of arrival will decouple from the estimates of the other parameters with the appropriate choice of array geometry. In three dimensions, again with an appropriate choice of array geometry, the estimates of the azimuth and elevation will decouple from the estimates of the other parameters, but due to the constraints of the model, will remain coupled to one another.
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Affiliation(s)
- S L Collier
- U.S. Army Research Laboratory, ATTN: AMSRL-CI-EE, 2800 Powder Mill Road, Adelphi, Maryland 20783-1197, USA.
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