1
|
Slane EG, Tambrini SJ, Cummings BS. Therapeutic potential of lipin inhibitors for the treatment of cancer. Biochem Pharmacol 2024; 222:116106. [PMID: 38442792 DOI: 10.1016/j.bcp.2024.116106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/28/2024] [Accepted: 03/01/2024] [Indexed: 03/07/2024]
Abstract
Lipins are phosphatidic acid phosphatases (PAP) that catalyze the conversion of phosphatidic acid (PA) to diacylglycerol (DAG). Three lipin isoforms have been identified: lipin-1, -2 and -3. In addition to their PAP activity, lipin-1 and -2 act as transcriptional coactivators and corepressors. Lipins have been intensely studied for their role in regulation of lipid metabolism and adipogenesis; however, lipins are hypothesized to mediate several pathologies, such as those involving metabolic diseases, neuropathy and even cognitive impairment. Recently, an emerging role for lipins have been proposed in cancer. The study of lipins in cancer has been hampered by lack of inhibitors that have selectivity for lipins, that differentiate between lipin family members, or that are suitable for in vivo studies. Such inhibitors have the potential to be extremely useful as both molecular tools and therapeutics. This review describes the expression and function of lipins in various tissues and their roles in several diseases, but with an emphasis on their possible role in cancer. The mechanisms by which lipins mediate cancer cell growth are discussed and the potential usefulness of selective lipin inhibitors is hypothesized. Finally, recent studies reporting the crystallization of lipin-1 are discussed to facilitate rational design of novel lipin inhibitors.
Collapse
Affiliation(s)
- Elizabeth G Slane
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
| | - Samantha J Tambrini
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
| | - Brian S Cummings
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA.
| |
Collapse
|
2
|
Karpale M, Kummu O, Kärkkäinen O, Lehtonen M, Näpänkangas J, Herfurth UM, Braeuning A, Rysä J, Hakkola J. Pregnane X receptor activation remodels glucose metabolism to promote NAFLD development in obese mice. Mol Metab 2023; 76:101779. [PMID: 37467962 PMCID: PMC10415798 DOI: 10.1016/j.molmet.2023.101779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/14/2023] [Accepted: 07/13/2023] [Indexed: 07/21/2023] Open
Abstract
OBJECTIVE Both obesity and exposure to chemicals may induce non-alcoholic fatty liver disease (NAFLD). Pregnane X Receptor (PXR) is a central target of metabolism disrupting chemicals and disturbs hepatic glucose and lipid metabolism. We hypothesized that the metabolic consequences of PXR activation may be modified by existing obesity and associated metabolic dysfunction. METHODS Wildtype and PXR knockout male mice were fed high-fat diet to induce obesity and metabolic dysfunction. PXR was activated with pregnenolone-16α-carbonitrile. Glucose metabolism, hepatosteatosis, insulin signaling, glucose uptake, liver glycogen, plasma and liver metabolomics, and liver, white adipose tissue, and muscle transcriptomics were investigated. RESULTS PXR activation aggravated obesity-induced liver steatosis by promoting lipogenesis and inhibiting fatty acid disposal. Accordingly, hepatic insulin sensitivity was impaired and circulating alanine aminotransferase level increased. Lipid synthesis was facilitated by increased liver glucose uptake and utilization of glycogen reserves resulting in dissociation of hepatosteatosis and hepatic insulin resistance from the systemic glucose tolerance and insulin sensitivity. Furthermore, glucagon-induced hepatic glucose production was impaired. PXR deficiency did not protect from the metabolic manifestations of obesity, but the liver transcriptomics and metabolomics profiling suggest diminished activation of inflammation and less prominent changes in the overall metabolite profile. CONCLUSIONS Obesity and PXR activation by chemical exposure have a synergistic effect on NAFLD development. To support liver fat accumulation the PXR activation reorganizes glucose metabolism that seemingly improves systemic glucose metabolism. This implies that obese individuals, already predisposed to metabolic diseases, may be more susceptible to harmful metabolic effects of PXR-activating drugs and environmental chemicals.
Collapse
Affiliation(s)
- Mikko Karpale
- Research Unit of Biomedicine and Internal Medicine, Biocenter Oulu, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Outi Kummu
- Research Unit of Biomedicine and Internal Medicine, Biocenter Oulu, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Olli Kärkkäinen
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland
| | - Marko Lehtonen
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland
| | - Juha Näpänkangas
- Department of Pathology, University of Oulu, Oulu University Hospital, Oulu, Finland
| | - Uta M Herfurth
- German Federal Institute for Risk Assessment (BfR), Department of Food Safety, Berlin, Germany
| | - Albert Braeuning
- German Federal Institute for Risk Assessment (BfR), Department of Food Safety, Berlin, Germany
| | - Jaana Rysä
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland
| | - Jukka Hakkola
- Research Unit of Biomedicine and Internal Medicine, Biocenter Oulu, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland.
| |
Collapse
|
3
|
Zhong R, Zhu Y, Zhang H, Huo Y, Huang Y, Cheng W, Liang P. Integrated lipidomic and transcriptomic analyses reveal the mechanism of large yellow croaker roe phospholipids on lipid metabolism in normal-diet mice. Food Funct 2022; 13:12852-12869. [PMID: 36444685 DOI: 10.1039/d2fo02736d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Large yellow croaker roe phospholipids (LYCRPLs) could regulate the accumulation of triglycerides and blood lipid levels. However, there exists little research on the mechanism of LYCRPLs on lipid metabolism in normal-diet mice. In this work, the mice on a normal diet were given low-dose, medium-dose, and high-dose LYCRPLs by intragastric administration for 6 weeks. At the same time, the physiological and biochemical indicators of the mice were determined, and the histomorphological observation of the liver and epididymal fat was carried out. In addition, we examined the gene expression and lipid metabolites in the liver of mice using transcriptomic and lipidomic and performed a correlation analysis. The results showed that LYCRPLs regulated the lipid metabolism of normal-diet mice by affecting the expression of the glycerolipid metabolism pathway, insulin resistance pathway, and cholesterol metabolism pathway. This study not only elucidated the main pathway by which LYCRPLs regulate lipid metabolism, but also laid a foundation for exploring LYCRPLs as functional food supplements.
Collapse
Affiliation(s)
- Rongbin Zhong
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian, China. .,Engineering Research Centre of Fujian-Taiwan Special Marine Food Processing and Nutrition, Ministry of Education, Fuzhou, 350002, Fujian, China
| | - Yujie Zhu
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian, China. .,Engineering Research Centre of Fujian-Taiwan Special Marine Food Processing and Nutrition, Ministry of Education, Fuzhou, 350002, Fujian, China
| | - Huadan Zhang
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian, China. .,Engineering Research Centre of Fujian-Taiwan Special Marine Food Processing and Nutrition, Ministry of Education, Fuzhou, 350002, Fujian, China
| | - Yuming Huo
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian, China. .,Engineering Research Centre of Fujian-Taiwan Special Marine Food Processing and Nutrition, Ministry of Education, Fuzhou, 350002, Fujian, China
| | - Ying Huang
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian, China. .,Engineering Research Centre of Fujian-Taiwan Special Marine Food Processing and Nutrition, Ministry of Education, Fuzhou, 350002, Fujian, China
| | - Wenjian Cheng
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian, China. .,Engineering Research Centre of Fujian-Taiwan Special Marine Food Processing and Nutrition, Ministry of Education, Fuzhou, 350002, Fujian, China
| | - Peng Liang
- College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian, China. .,Engineering Research Centre of Fujian-Taiwan Special Marine Food Processing and Nutrition, Ministry of Education, Fuzhou, 350002, Fujian, China
| |
Collapse
|
4
|
Gwon MH, Im YS, Seo AR, Kim KY, Moon HR, Yun JM. Phenethyl Isothiocyanate Protects against High Fat/Cholesterol Diet-Induced Obesity and Atherosclerosis in C57BL/6 Mice. Nutrients 2020; 12:nu12123657. [PMID: 33261070 PMCID: PMC7761196 DOI: 10.3390/nu12123657] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/25/2020] [Accepted: 11/25/2020] [Indexed: 12/13/2022] Open
Abstract
This study concerns obesity-related atherosclerosis, hyperlipidemia, and chronic inflammation. We studied the anti-obesity and anti-atherosclerosis effects of phenethyl isothiocyanate (PEITC) and explored their underlying mechanisms. We established an animal model of high fat/cholesterol-induced obesity in C57BL/6 mice fed for 13 weeks. We divided the mice into five groups: control (CON), high fat/cholesterol (HFCD), HFCD with 3 mg/kg/day gallic acid (HFCD + G), and HFCD with PEITC (30 and 75 mg/kg/day; HFCD + P30 and P75). The body weight, total cholesterol, and triglyceride were significantly lower in the HFCD + P75 group than in the HFCD group. Hepatic lipid accumulation and atherosclerotic plaque formation in the aorta were significantly lower in both HFCD + PEITC groups than in the HFCD group, as revealed by hematoxylin and eosin (H&E) staining. To elucidate the mechanism, we identified the expression of genes related to inflammation, reverse cholesterol transport, and lipid accumulation pathway in the liver. The expression levels of peroxisome proliferator activated receptor gamma (PPARγ), liver-X-receptor α (LXR-α), and ATP binding cassette subfamily A member 1 (ABCA1) were increased, while those of scavenger receptor A (SR-A1), cluster of differentiation 36 (CD36), and nuclear factor-kappa B (NF-κB) were decreased in the HFCD + P75 group compared with those in the HFCD group. Moreover, PEITC modulated H3K9 and H3K27 acetylation, H3K4 dimethylation, and H3K27 di-/trimethylation in the HFCD + P75 group. We, therefore, suggest that supplementation with PEITC may be a potential candidate for the treatment and prevention of atherosclerosis and obesity.
Collapse
Affiliation(s)
- Min-Hee Gwon
- Nutrition Education Major, Graduate School of Education, Chonnam National University, Gwangju 61186, Korea;
| | - Young-Sun Im
- Department of Food and Nutrition, Chonnam National University, Gwangju 61186, Korea; (Y.-S.I.); (A.-R.S.); (K.Y.K.); (H.-R.M.)
| | - A-Reum Seo
- Department of Food and Nutrition, Chonnam National University, Gwangju 61186, Korea; (Y.-S.I.); (A.-R.S.); (K.Y.K.); (H.-R.M.)
| | - Kyoung Yun Kim
- Department of Food and Nutrition, Chonnam National University, Gwangju 61186, Korea; (Y.-S.I.); (A.-R.S.); (K.Y.K.); (H.-R.M.)
| | - Ha-Rin Moon
- Department of Food and Nutrition, Chonnam National University, Gwangju 61186, Korea; (Y.-S.I.); (A.-R.S.); (K.Y.K.); (H.-R.M.)
| | - Jung-Mi Yun
- Department of Food and Nutrition, Chonnam National University, Gwangju 61186, Korea; (Y.-S.I.); (A.-R.S.); (K.Y.K.); (H.-R.M.)
- Correspondence: ; Tel.: +82-62-530-1332
| |
Collapse
|
5
|
Lutkewitte AJ, Finck BN. Regulation of Signaling and Metabolism by Lipin-mediated Phosphatidic Acid Phosphohydrolase Activity. Biomolecules 2020; 10:E1386. [PMID: 33003344 PMCID: PMC7600782 DOI: 10.3390/biom10101386] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 12/15/2022] Open
Abstract
Phosphatidic acid (PA) is a glycerophospholipid intermediate in the triglyceride synthesis pathway that has incredibly important structural functions as a component of cell membranes and dynamic effects on intracellular and intercellular signaling pathways. Although there are many pathways to synthesize and degrade PA, a family of PA phosphohydrolases (lipin family proteins) that generate diacylglycerol constitute the primary pathway for PA incorporation into triglycerides. Previously, it was believed that the pool of PA used to synthesize triglyceride was distinct, compartmentalized, and did not widely intersect with signaling pathways. However, we now know that modulating the activity of lipin 1 has profound effects on signaling in a variety of cell types. Indeed, in most tissues except adipose tissue, lipin-mediated PA phosphohydrolase activity is far from limiting for normal rates of triglyceride synthesis, but rather impacts critical signaling cascades that control cellular homeostasis. In this review, we will discuss how lipin-mediated control of PA concentrations regulates metabolism and signaling in mammalian organisms.
Collapse
Affiliation(s)
| | - Brian N. Finck
- Center for Human Nutrition, Division of Geriatrics and Nutritional Sciences, Department of Medicine, Washington University School of Medicine, Euclid Avenue, Campus Box 8031, St. Louis, MO 63110, USA;
| |
Collapse
|
6
|
Jin H, Lee K, Chei S, Oh HJ, Lee KP, Lee BY. Ecklonia stolonifera Extract Suppresses Lipid Accumulation by Promoting Lipolysis and Adipose Browning in High-Fat Diet-Induced Obese Male Mice. Cells 2020; 9:E871. [PMID: 32252474 PMCID: PMC7226821 DOI: 10.3390/cells9040871] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/21/2020] [Accepted: 02/21/2020] [Indexed: 12/18/2022] Open
Abstract
Obesity develops due to an energy imbalance and manifests as the storage of excess triglyceride (TG) in white adipose tissue (WAT). Recent studies have determined that edible natural materials can reduce lipid accumulation and promote browning in WAT. We aimed to determine whether Ecklonia stolonifera extract (ESE) would increase the energy expenditure in high-fat diet (HFD)-induced obese mice and 3T3-L1 cells by upregulating lipolysis and browning. ESE is an edible brown marine alga that belongs to the family Laminariaceae and contains dieckol, a phlorotannin. We report that ESE inhibits body mass gain by regulating the expression of proteins involved in adipogenesis and lipogenesis. In addition, ESE activates protein kinase A (PKA) and increases the expression of lipolytic enzymes including adipose triglyceride lipase (ATGL), phosphorylated hormone-sensitive lipase (p-HSL), and monoacylglycerol lipase (MGL) and also thermogenic genes, such as carnitine palmitoyltransferase 1 (CPT1), PR domain-containing 16 (PRDM16), and uncoupling protein 1 (UCP1). These findings indicate that ESE may represent a promising natural means of preventing obesity and obesity-related metabolic diseases.
Collapse
Affiliation(s)
- Heegu Jin
- Department of Food Science and Biotechnology, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Korea; (H.J.); (K.L.); (S.C.); (H.-J.O.)
| | - Kippeum Lee
- Department of Food Science and Biotechnology, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Korea; (H.J.); (K.L.); (S.C.); (H.-J.O.)
| | - Sungwoo Chei
- Department of Food Science and Biotechnology, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Korea; (H.J.); (K.L.); (S.C.); (H.-J.O.)
| | - Hyun-Ji Oh
- Department of Food Science and Biotechnology, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Korea; (H.J.); (K.L.); (S.C.); (H.-J.O.)
| | | | - Boo-Yong Lee
- Department of Food Science and Biotechnology, College of Life Science, CHA University, Seongnam, Gyeonggi 13488, Korea; (H.J.); (K.L.); (S.C.); (H.-J.O.)
| |
Collapse
|
7
|
Effects of Dietary Fatty Acids from Different Sources on Growth Performance, Meat Quality, Muscle Fatty Acid Deposition, and Antioxidant Capacity in Broilers. Animals (Basel) 2020; 10:ani10030508. [PMID: 32204327 PMCID: PMC7143790 DOI: 10.3390/ani10030508] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 02/06/2023] Open
Abstract
Simple Summary The findings in the current study reveal that dietary fish oil or a combination of linseed oil and microalgae could be effective in improving growth performance, carcass traits, muscle fatty acid deposition, and antioxidant capacity in broilers compared with traditional soybean oil in broilers. Abstract This study aimed to investigate the efficiency of dietary fatty acids from various sources on growth performance, meat quality, muscle fatty acid deposition and antioxidant capacity in broilers. 126 Arbor Acres broilers (1 d-old, initial body weight of 45.5 ± 0.72 g) were randomly assigned to three treatments with seven cages per treatment and six broilers per cage. The dietary treatments included: (1) corn–soybean meal basal diet containing 3% soybean oil (control diet, CTL); (2) basal diet + 1% microalgae + 1% linseed oil + 1% soybean oil (ML); (3) basal diet + 2% fish oil + 1% soybean oil (FS). The trial consisted of phase 1 (day 1 to 21) and 2 (day 22 to 42). Compared with CTL, broilers fed ML or FS diet showed improved (p < 0.05) average daily gain in phase 1, 2, and overall (day 1 to 42), as well as a decreased (p < 0.05) feed conversion ratio in phase 1 and overall. On day 42, broilers supplemented with FS diet showed increased (p ≤ 0.05) the relative weights of pancreas and liver, as well as higher (p < 0.05) redness value in breast and thigh muscle compared with CTL. Broilers offered ML or FS diet had lower (p < 0.05) the relative weight of abdominal fat and total serum cholesterol content in phase 1, and increased (p < 0.05) contents of serum glucose, n-3 polyunsaturated fatty acids (PUFA), eicosacagetaenoic acid, docosahexaenoic acid, glutathione peroxidase, superoxide dismutase and total antioxidant capacity, as well as lower (p < 0.05) concentrations of malondialdehyde, n-6 PUFA, and n-6/n-3 PUFA ratio in breast and thigh muscle compared with CTL. This research indicates that diets supplemented with fish oil or a combination of microalgae and linseed oil experience improved performance, antioxidant capacities and n-3 PUFA profile in muscle of broilers compared with traditional soybean oil supplemented diets
Collapse
|
8
|
Abstract
The cause of insulin resistance in obesity and type 2 diabetes mellitus (T2DM) is not limited to impaired insulin signalling but also involves the complex interplay of multiple metabolic pathways. The analysis of large data sets generated by metabolomics and lipidomics has shed new light on the roles of metabolites such as lipids, amino acids and bile acids in modulating insulin sensitivity. Metabolites can regulate insulin sensitivity directly by modulating components of the insulin signalling pathway, such as insulin receptor substrates (IRSs) and AKT, and indirectly by altering the flux of substrates through multiple metabolic pathways, including lipogenesis, lipid oxidation, protein synthesis and degradation and hepatic gluconeogenesis. Moreover, the post-translational modification of proteins by metabolites and lipids, including acetylation and palmitoylation, can alter protein function. Furthermore, the role of the microbiota in regulating substrate metabolism and insulin sensitivity is unfolding. In this Review, we discuss the emerging roles of metabolites in the pathogenesis of insulin resistance and T2DM. A comprehensive understanding of the metabolic adaptations involved in insulin resistance may enable the identification of novel targets for improving insulin sensitivity and preventing, and treating, T2DM.
Collapse
|
9
|
Zhang X, Xie X, Heckmann BL, Saarinen AM, Gu H, Zechner R, Liu J. Identification of an intrinsic lysophosphatidic acid acyltransferase activity in the lipolytic inhibitor G 0/G 1 switch gene 2 (G0S2). FASEB J 2019; 33:6655-6666. [PMID: 30802154 PMCID: PMC6463910 DOI: 10.1096/fj.201802502r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
G0/G1 switch gene 2 (G0S2) is a specific inhibitor of adipose triglyceride lipase (ATGL), the rate-limiting enzyme for intracellular lipolysis. Recent studies show that G0S2 plays a critical role in promoting triacylglycerol (TG) accumulation in the liver, and its encoding gene is a direct target of a major lipogenic transcription factor liver X receptor (LXR)α. Here we sought to investigate a lipolysis-independent role of G0S2 in hepatic triglyceride synthesis. Knockdown of G0S2 decreased hepatic TG content in mice with ATGL ablation. Conversely, overexpression of G0S2 promoted fatty acid incorporation into TGs and diacylglycerols in both wild-type and ATGL-deficient hepatocytes. Biochemical characterization showed that G0S2 mediates phosphatidic acid synthesis from lysophosphatidic acid (LPA) and acyl-coenzyme A. In response to a high-sucrose lipogenic diet, G0S2 is up-regulated via LXRα and required for the increased TG accumulation in liver. Furthermore, deletion of a distinct 4-aa motif necessary for the LPA-specific acyltransferase (LPAAT) activity impaired G0S2's ability to mediate TG synthesis both in vitro and in vivo. These studies identify G0S2 as a dual-function regulator of lipid metabolism as well as a novel mechanism whereby hepatic TG storage is promoted in response to lipogenic stimulation. In addition to its role as a lipolytic inhibitor, G0S2 is capable of directly promoting TG synthesis by acting as a lipid-synthesizing enzyme.-Zhang, X., Xie, X., Heckmann, B. L., Saarinen, A. M., Gu, H., Zechner, R., Liu, J. Identification of an intrinsic lysophosphatidic acid acyltransferase activity in the lipolytic inhibitor G0/G1 switch gene 2 (G0S2).
Collapse
Affiliation(s)
- Xiaodong Zhang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Xitao Xie
- Department of Chemical Engineering, Arizona State University, Tempe, Arizona, USA
| | - Bradlee L. Heckmann
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Alicia M. Saarinen
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Haiwei Gu
- Center for Metabolic and Vascular Biology, College of Health Solutions, Arizona State University, Scottsdale, Arizona, USA
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Jun Liu
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA;,Division of Endocrinology, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA,Correspondence: Mayo Clinic College of Medicine and Science, Guggenheim Building 14-05, 222 3rd Ave. SW, Rochester, MN 55905, USA. E-mail:
| |
Collapse
|
10
|
Gaballah HH, El‐Horany HE, Helal DS. Mitigative effects of the bioactive flavonol fisetin on high‐fat/high‐sucrose induced nonalcoholic fatty liver disease in rats. J Cell Biochem 2019; 120:12762-12774. [DOI: 10.1002/jcb.28544] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 01/16/2019] [Accepted: 01/24/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Hanaa H. Gaballah
- Department of Medical Biochemistry Faculty of Medicine, Tanta University Tanta Egypt
| | - Hemat E. El‐Horany
- Department of Medical Biochemistry Faculty of Medicine, Tanta University Tanta Egypt
| | - Duaa S. Helal
- Department of Histopathology Faculty of Medicine, Tanta University Tanta Egypt
| |
Collapse
|
11
|
Jama A, Huang D, Alshudukhi AA, Chrast R, Ren H. Lipin1 is required for skeletal muscle development by regulating MEF2c and MyoD expression. J Physiol 2018; 597:889-901. [PMID: 30511745 DOI: 10.1113/jp276919] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 12/03/2018] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS Lipin1 is critical for skeletal muscle development. Lipin1 regulates MyoD and myocyte-specific enhancer factor 2C (MEF2c) expression via the protein kinase C (PKC)/histone deacetylase 5-mediated pathway. Inhibition of PKCμ activity suppresses myoblast differentiation by inhibiting MyoD and MEF2c expression. ABSTRACT Our previous characterization of global lipin1-deficient (fld) mice demonstrated that lipin1 played a novel role in skeletal muscle (SM) regeneration. The present study using cell type-specific Myf5-cre;Lipin1fl/fl conditional knockout mice (Lipin1Myf5cKO ) shows that lipin1 is a major determinant of SM development. Lipin1 deficiency induced reduced muscle mass and myopathy. Our results from lipin1-deficient myoblasts suggested that lipin1 regulates myoblast differentiation via the protein kinase Cμ (PKCμ)/histone deacetylase 5 (HDAC5)/myocyte-specific enhancer factor 2C (MEF2c):MyoD-mediated pathway. Lipin1 deficiency leads to the suppression of PKC isoform activities, as well as inhibition of the downstream target of PKCμ, class II deacetylase HDAC5 nuclear export, and, consequently, inhibition of MEF2c and MyoD expression in the SM of lipin1Myf5cKO mice. Restoration of diacylglycerol-mediated signalling in lipin1 deficient myoblasts by phorbol 12-myristate 13-acetate transiently activated PKC and HDAC5, and upregulated MEF2c expression. Our findings provide insights into the signalling circuitry that regulates SM development, and have important implications for developing intervention aimed at treating muscular dystrophy.
Collapse
Affiliation(s)
- Abdulrahman Jama
- Department of Biochemistry and Molecular Biology, Wright State University, Dayton, OH, USA
| | - Dengtong Huang
- Department of Biochemistry and Molecular Biology, Wright State University, Dayton, OH, USA
| | - Abdullah A Alshudukhi
- Department of Biochemistry and Molecular Biology, Wright State University, Dayton, OH, USA
| | - Roman Chrast
- Department of Neuroscience and Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Hongmei Ren
- Department of Biochemistry and Molecular Biology, Wright State University, Dayton, OH, USA
| |
Collapse
|
12
|
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] [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.
Collapse
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
| |
Collapse
|
13
|
Lee J, Hong SW, Kwon H, Park SE, Rhee EJ, Park CY, Oh KW, Park SW, Lee WY. Exendin-4 improves ER stress-induced lipid accumulation and regulates lipin-1 signaling in HepG2 cells. Cell Stress Chaperones 2018; 23:629-638. [PMID: 29934713 PMCID: PMC6045528 DOI: 10.1007/s12192-017-0872-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 12/20/2017] [Accepted: 12/25/2017] [Indexed: 12/12/2022] Open
Abstract
Lipin-1 performs dual function during lipid metabolism, i.e., it functions as a transcriptional coactivator and as a phosphatidate phosphatase during triglyceride biosynthesis. We investigated whether exendin-4 prevented endoplasmic reticulum (ER) stress-induced hepatic steatosis and whether the protective effects of exendin-4 were associated with lipin-1 signaling. Tunicamycin and thapsigargin, ER stress inducers, increased triglycerides (TG) content and expression of genes encoding lipid droplet surface proteins. Exendin-4 decreased the expression of ER stress markers phosphorylated PKR like ER kinase (PERK), phosphorylated inositol-requiring enzyme 1 alpha (IRE1α), and glucose-regulated protein 78 kDa (GRP78) proteins and spliced X-box binding protein 1 (XBP-1s) mRNA and increased the expression of genes encoding lipolytic enzymes hormone-sensitive lipase (HSL) and monoacylglycerol lipase (MGL) and VLDL assembly-associated proteins microsomal triglyceride transfer protein (MTP) and apolipoprotein B (APOB) in tunicamycin-pretreated cells. Moreover, exendin-4 significantly decreased lipin-1β/α ratio by increasing SFRP10 and increased lipin-1 nuclear localization. The decrease in lipin-1β/α ratio was also observed in SIRT1 and AMPK agonist-treated cells. These data suggest that exendin-4 improves ER stress-induced hepatic lipid accumulation by increasing lipolysis and VLDL assembly, which is partially mediated by the regulation of lipin-1 signaling.
Collapse
Affiliation(s)
- Jinmi Lee
- Institute of Medical Research, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, 03181, Republic of Korea
| | - Seok-Woo Hong
- Institute of Medical Research, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, 03181, Republic of Korea
| | - Hyemi Kwon
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, 03181, Republic of Korea
| | - Se Eun Park
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, 03181, Republic of Korea
| | - Eun-Jung Rhee
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, 03181, Republic of Korea
| | - Cheol-Young Park
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, 03181, Republic of Korea
| | - Ki-Won Oh
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, 03181, Republic of Korea
| | - Sung-Woo Park
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, 03181, Republic of Korea
| | - Won-Young Lee
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, 03181, Republic of Korea.
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, #29 Seamunan-ro, Jongro-Ku, Seoul, 03181, Republic of Korea.
| |
Collapse
|
14
|
Tip60-mediated lipin 1 acetylation and ER translocation determine triacylglycerol synthesis rate. Nat Commun 2018; 9:1916. [PMID: 29765047 PMCID: PMC5953937 DOI: 10.1038/s41467-018-04363-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 04/25/2018] [Indexed: 12/15/2022] Open
Abstract
Obesity is characterized by excessive fatty acid conversion to triacylglycerols (TAGs) in adipose tissues. However, how signaling networks sense fatty acids and connect to the stimulation of lipid synthesis remains elusive. Here, we show that homozygous knock-in mice carrying a point mutation at the Ser86 phosphorylation site of acetyltransferase Tip60 (Tip60SA/SA) display remarkably reduced body fat mass, and Tip60SA/SA females fail to nurture pups to adulthood due to severely reduced milk TAGs. Mechanistically, fatty acids stimulate Tip60-dependent acetylation and endoplasmic reticulum translocation of phosphatidic acid phosphatase lipin 1 to generate diacylglycerol for TAG synthesis, which is repressed by deacetylase Sirt1. Inhibition of Tip60 activity strongly blocks fatty acid-induced TAG synthesis while Sirt1 suppression leads to increased adiposity. Genetic analysis of loss-of-function mutants in Saccharomyces cerevisiae reveals a requirement of ESA1, yeast ortholog of Tip60, in TAG accumulation. These findings uncover a conserved mechanism linking fatty acid sensing to fat synthesis. The acetyltransferase Tip60 mediates signaling pathways by acetylating non-histone proteins. Here the authors show that fatty acids induce Tip60–dependent acetylation of phosphatidic acid phosphatase lipin1 which, then, translocates to the ER and generates diacylglycerols for triglyceride synthesis.
Collapse
|
15
|
Vozenilek AE, Navratil AR, Green JM, Coleman DT, Blackburn CMR, Finney AC, Pearson BH, Chrast R, Finck BN, Klein RL, Orr AW, Woolard MD. Macrophage-Associated Lipin-1 Enzymatic Activity Contributes to Modified Low-Density Lipoprotein-Induced Proinflammatory Signaling and Atherosclerosis. Arterioscler Thromb Vasc Biol 2017; 38:324-334. [PMID: 29217509 DOI: 10.1161/atvbaha.117.310455] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 11/20/2017] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Macrophage proinflammatory responses induced by modified low-density lipoproteins (modLDL) contribute to atherosclerotic progression. How modLDL causes macrophages to become proinflammatory is still enigmatic. Macrophage foam cell formation induced by modLDL requires glycerolipid synthesis. Lipin-1, a key enzyme in the glycerolipid synthesis pathway, contributes to modLDL-elicited macrophage proinflammatory responses in vitro. The objective of this study was to determine whether macrophage-associated lipin-1 contributes to atherogenesis and to assess its role in modLDL-mediated signaling in macrophages. APPROACH AND RESULTS We developed mice lacking lipin-1 in myeloid-derived cells and used adeno-associated viral vector 8 expressing the gain-of-function mutation of mouse proprotein convertase subtilisin/kexin type 9 (adeno-associated viral vector 8-proprotein convertase subtilisin/kexin type 9) to induce hypercholesterolemia and plaque formation. Mice lacking myeloid-associated lipin-1 had reduced atherosclerotic burden compared with control mice despite similar plasma lipid levels. Stimulation of bone marrow-derived macrophages with modLDL activated a persistent protein kinase Cα/βII-extracellular receptor kinase1/2-jun proto-oncogene signaling cascade that contributed to macrophage proinflammatory responses that was dependent on lipin-1 enzymatic activity. CONCLUSIONS Our data demonstrate that macrophage-associated lipin-1 is atherogenic, likely through persistent activation of a protein kinase Cα/βII-extracellular receptor kinase1/2-jun proto-oncogene signaling cascade that contributes to foam cell proinflammatory responses. Taken together, these results suggest that modLDL-induced foam cell formation and modLDL-induced macrophage proinflammatory responses are not independent consequences of modLDL stimulation but rather are both directly influenced by enhanced lipid synthesis.
Collapse
Affiliation(s)
- Aimee E Vozenilek
- From the Department of Microbiology and Immunology (A.E.V., C.M.R.B., M.D.W.), Department of Pathology and Translational Pathobiology (J.M.G., B.H.P., A.W.O.), Department of Cell Biology and Anatomy (A.C.F.), Feist-Weiller Cancer Center (D.T.C.), and Pharmacology, Toxicology, and Neuroscience (R.L.K.), Louisiana State University Health Sciences Center, Shreveport; Department of Pharmacology, University of California San Diego, La Jolla (A.R.N.); Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (R.C.); and Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO (B.N.F.)
| | - Aaron R Navratil
- From the Department of Microbiology and Immunology (A.E.V., C.M.R.B., M.D.W.), Department of Pathology and Translational Pathobiology (J.M.G., B.H.P., A.W.O.), Department of Cell Biology and Anatomy (A.C.F.), Feist-Weiller Cancer Center (D.T.C.), and Pharmacology, Toxicology, and Neuroscience (R.L.K.), Louisiana State University Health Sciences Center, Shreveport; Department of Pharmacology, University of California San Diego, La Jolla (A.R.N.); Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (R.C.); and Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO (B.N.F.)
| | - Jonette M Green
- From the Department of Microbiology and Immunology (A.E.V., C.M.R.B., M.D.W.), Department of Pathology and Translational Pathobiology (J.M.G., B.H.P., A.W.O.), Department of Cell Biology and Anatomy (A.C.F.), Feist-Weiller Cancer Center (D.T.C.), and Pharmacology, Toxicology, and Neuroscience (R.L.K.), Louisiana State University Health Sciences Center, Shreveport; Department of Pharmacology, University of California San Diego, La Jolla (A.R.N.); Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (R.C.); and Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO (B.N.F.)
| | - David T Coleman
- From the Department of Microbiology and Immunology (A.E.V., C.M.R.B., M.D.W.), Department of Pathology and Translational Pathobiology (J.M.G., B.H.P., A.W.O.), Department of Cell Biology and Anatomy (A.C.F.), Feist-Weiller Cancer Center (D.T.C.), and Pharmacology, Toxicology, and Neuroscience (R.L.K.), Louisiana State University Health Sciences Center, Shreveport; Department of Pharmacology, University of California San Diego, La Jolla (A.R.N.); Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (R.C.); and Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO (B.N.F.)
| | - Cassidy M R Blackburn
- From the Department of Microbiology and Immunology (A.E.V., C.M.R.B., M.D.W.), Department of Pathology and Translational Pathobiology (J.M.G., B.H.P., A.W.O.), Department of Cell Biology and Anatomy (A.C.F.), Feist-Weiller Cancer Center (D.T.C.), and Pharmacology, Toxicology, and Neuroscience (R.L.K.), Louisiana State University Health Sciences Center, Shreveport; Department of Pharmacology, University of California San Diego, La Jolla (A.R.N.); Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (R.C.); and Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO (B.N.F.)
| | - Alexandra C Finney
- From the Department of Microbiology and Immunology (A.E.V., C.M.R.B., M.D.W.), Department of Pathology and Translational Pathobiology (J.M.G., B.H.P., A.W.O.), Department of Cell Biology and Anatomy (A.C.F.), Feist-Weiller Cancer Center (D.T.C.), and Pharmacology, Toxicology, and Neuroscience (R.L.K.), Louisiana State University Health Sciences Center, Shreveport; Department of Pharmacology, University of California San Diego, La Jolla (A.R.N.); Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (R.C.); and Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO (B.N.F.)
| | - Brenna H Pearson
- From the Department of Microbiology and Immunology (A.E.V., C.M.R.B., M.D.W.), Department of Pathology and Translational Pathobiology (J.M.G., B.H.P., A.W.O.), Department of Cell Biology and Anatomy (A.C.F.), Feist-Weiller Cancer Center (D.T.C.), and Pharmacology, Toxicology, and Neuroscience (R.L.K.), Louisiana State University Health Sciences Center, Shreveport; Department of Pharmacology, University of California San Diego, La Jolla (A.R.N.); Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (R.C.); and Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO (B.N.F.)
| | - Roman Chrast
- From the Department of Microbiology and Immunology (A.E.V., C.M.R.B., M.D.W.), Department of Pathology and Translational Pathobiology (J.M.G., B.H.P., A.W.O.), Department of Cell Biology and Anatomy (A.C.F.), Feist-Weiller Cancer Center (D.T.C.), and Pharmacology, Toxicology, and Neuroscience (R.L.K.), Louisiana State University Health Sciences Center, Shreveport; Department of Pharmacology, University of California San Diego, La Jolla (A.R.N.); Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (R.C.); and Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO (B.N.F.)
| | - Brian N Finck
- From the Department of Microbiology and Immunology (A.E.V., C.M.R.B., M.D.W.), Department of Pathology and Translational Pathobiology (J.M.G., B.H.P., A.W.O.), Department of Cell Biology and Anatomy (A.C.F.), Feist-Weiller Cancer Center (D.T.C.), and Pharmacology, Toxicology, and Neuroscience (R.L.K.), Louisiana State University Health Sciences Center, Shreveport; Department of Pharmacology, University of California San Diego, La Jolla (A.R.N.); Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (R.C.); and Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO (B.N.F.)
| | - Ronald L Klein
- From the Department of Microbiology and Immunology (A.E.V., C.M.R.B., M.D.W.), Department of Pathology and Translational Pathobiology (J.M.G., B.H.P., A.W.O.), Department of Cell Biology and Anatomy (A.C.F.), Feist-Weiller Cancer Center (D.T.C.), and Pharmacology, Toxicology, and Neuroscience (R.L.K.), Louisiana State University Health Sciences Center, Shreveport; Department of Pharmacology, University of California San Diego, La Jolla (A.R.N.); Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (R.C.); and Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO (B.N.F.)
| | - A Wayne Orr
- From the Department of Microbiology and Immunology (A.E.V., C.M.R.B., M.D.W.), Department of Pathology and Translational Pathobiology (J.M.G., B.H.P., A.W.O.), Department of Cell Biology and Anatomy (A.C.F.), Feist-Weiller Cancer Center (D.T.C.), and Pharmacology, Toxicology, and Neuroscience (R.L.K.), Louisiana State University Health Sciences Center, Shreveport; Department of Pharmacology, University of California San Diego, La Jolla (A.R.N.); Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (R.C.); and Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO (B.N.F.)
| | - Matthew D Woolard
- From the Department of Microbiology and Immunology (A.E.V., C.M.R.B., M.D.W.), Department of Pathology and Translational Pathobiology (J.M.G., B.H.P., A.W.O.), Department of Cell Biology and Anatomy (A.C.F.), Feist-Weiller Cancer Center (D.T.C.), and Pharmacology, Toxicology, and Neuroscience (R.L.K.), Louisiana State University Health Sciences Center, Shreveport; Department of Pharmacology, University of California San Diego, La Jolla (A.R.N.); Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden (R.C.); and Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO (B.N.F.).
| |
Collapse
|
16
|
Wang H, Airola MV, Reue K. How lipid droplets "TAG" along: Glycerolipid synthetic enzymes and lipid storage. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1131-1145. [PMID: 28642195 PMCID: PMC5688854 DOI: 10.1016/j.bbalip.2017.06.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/15/2017] [Accepted: 06/15/2017] [Indexed: 02/06/2023]
Abstract
Triacylglycerols (TAG) serve as the predominant form of energy storage in mammalian cells, and TAG synthesis influences conditions such as obesity, fatty liver, and insulin resistance. In most tissues, the glycerol 3-phosphate pathway enzymes are responsible for TAG synthesis, and the regulation and function of these enzymes is therefore important for metabolic homeostasis. Here we review the sites and regulation of glycerol-3-phosphate acyltransferase (GPAT), acylglycerol-3-phosphate acyltransferase (AGPAT), lipin phosphatidic acid phosphatase (PAP), and diacylglycerol acyltransferase (DGAT) enzyme action. We highlight the critical roles that these enzymes play in human health by reviewing Mendelian disorders that result from mutation in the corresponding genes. We also summarize the valuable insights that genetically engineered mouse models have provided into the cellular and physiological roles of GPATs, AGPATs, lipins and DGATs. Finally, we comment on the status and feasibility of therapeutic approaches to metabolic disease that target enzymes of the glycerol 3-phosphate pathway. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.
Collapse
Affiliation(s)
- Huan Wang
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Michael V Airola
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States; Molecular Biology Institute, University of California, Los Angeles, CA, United States.
| |
Collapse
|
17
|
Changing dietary n-6:n-3 ratio using different oil sources affects performance, behavior, cytokines mRNA expression and meat fatty acid profile of broiler chickens. ACTA ACUST UNITED AC 2017; 4:44-51. [PMID: 30167483 PMCID: PMC6112305 DOI: 10.1016/j.aninu.2017.08.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/25/2017] [Accepted: 08/05/2017] [Indexed: 12/22/2022]
Abstract
Typical formulated broiler diets are deficient in n-3 poly-unsaturated fatty acids (PUFA) due to widening n-6:n-3 PUFA ratio which could greatly affect performance, immune system of birds and, more importantly, meat quality. This study was conducted to evaluate the effect of modifying dietary n-6:n-3 PUFA ratio from plant and animal oil sources on performance, behavior, cytokine mRNA expression, antioxidative status and meat fatty acid profile of broiler chickens. Birds (n = 420) were fed 7 diets enriched with different dietary oil sources and ratios as follows: sunflower oil in control diet (C); fish oil (FO); 1:1 ratio of sunflower oil to FO (C1FO1); 3:1 ratio of sunflower oil to fish oil (C3FO1); linseed oil (LO); 1:1 ratio of sunflower oil to linseed oil (C1LO1); 3:1 ratio of sunflower oil to linseed oil (C3LO1), resulting in dietary n-6:n-3 ratios of approximately 40:1, 1.5:1, 4:1, 8:1, 1:1, 2.5:1 and 5:1, respectively. The best final body weight, feed conversion ratio as well as protein efficiency ratio of broilers were recorded in the C1FO1 and C1LO1 groups. Compared with the control group, the dressing percentage and breast and thigh yield were highest in the C1FO1 and C1LO1 groups. Narrowing the dietary n-6:n-3 ratio increased (P < 0.05) n-3 PUFA content of breast meat. Moreover, the breast meat contents of eicosapentaenoic acid and docosahexaenoic acid increased (P < 0.05) with increasing dietary FO whereas α-linolenic acid content was higher with LO supplementation. Also, enriching the diets with n-3 PUFA from FO and LO clearly decreased (P < 0.05) serum total cholesterol, triglycerides and very low-density lipoproteins and enhanced antioxidative status. The feeding frequency was decreased (P < 0.05) in the C1FO1 and C1LO1 groups. Likewise, n-3 PUFA-enriched diets enhanced the frequency of preening, wing flapping and flightiness. Animal oil source addition, compared to plant oil, to broiler diets enhanced the relative mRNA expression of interferon gamma, interleukin-1 beta, interleukin-2 and interleukin-6 genes, especially at low n-6:n-3 ratios. This study has clearly shown that narrowing n-6:n-3 ratio through the addition of FO or LO improved performance and immune response of broilers and resulted in healthy chicken meat, enriched with long chain n-3 PUFA.
Collapse
|
18
|
He J, Zhang F, Tay LWR, Boroda S, Nian W, Levental KR, Levental I, Harris TE, Chang JT, Du G. Lipin-1 regulation of phospholipid synthesis maintains endoplasmic reticulum homeostasis and is critical for triple-negative breast cancer cell survival. FASEB J 2017; 31:2893-2904. [PMID: 28347999 DOI: 10.1096/fj.201601353r] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 03/06/2017] [Indexed: 12/22/2022]
Abstract
Cancer cells reprogram their metabolism to increase the synthesis of macromolecules for rapid proliferation. Compared to fatty acids, much less is known about the synthesis of phospholipids, which is essential for membrane biogenesis in cancer cells. We found that LPIN1, which encodes lipin-1, a phosphatidic acid phosphatase (PAP) controlling the rate-limiting step in the phospholipid synthesis pathway, is highly up-regulated in basal-like triple-negative breast cancer (TNBC). Moreover, high LPIN1 expression correlates with the poor prognosis of these patients. Knockdown of LPIN1 increases apoptosis in basal-like TNBC cell lines, whereas it has minimal or less effect on normal human mammary gland epithelial cells (HMECs) and estrogen receptor-positive breast cancer cell lines. Fatty acid incorporation and lipidomics analyses showed that LPIN1 knockdown blocks phospholipid synthesis and changes membrane lipid compositions that ultimately induce the activation of 1 of the 3 branches of unfolded protein responses, the inositol-requiring enzyme-1α pathway. We also show for the first time, to our knowledge, that lipin-1 knockdown significantly inhibits tumor growth in vivo using an orthotopic xenograft breast mouse model. Our results suggest that lipin-1 is a potential target for cancer therapy.-He, J., Zhang, F., Tay, L. W. R., Boroda, S., Nian, W., Levental, K. R., Levental, I., Harris, T. E., Chang, J. T., Du, G. Lipin-1 regulation of phospholipid synthesis maintains endoplasmic reticulum homeostasis and is critical for triple-negative breast cancer cell survival.
Collapse
Affiliation(s)
- Jingquan He
- Department of Integrative Biology and Pharmacology University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Feng Zhang
- Department of Integrative Biology and Pharmacology University of Texas Health Science Center at Houston, Houston, Texas, USA.,Core Facility, Department of Clinical Laboratory, Quzhou People's Hospital, Quzhou, China
| | - Li Wei Rachel Tay
- Department of Integrative Biology and Pharmacology University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Salome Boroda
- Department of Pharmacology, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Weiqi Nian
- Department of Integrative Biology and Pharmacology University of Texas Health Science Center at Houston, Houston, Texas, USA.,Key Laboratory of Oncology, Chongqing Cancer Hospital and Institute and Cancer Center, Chongqing, China
| | - Kandice R Levental
- Department of Integrative Biology and Pharmacology University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Ilya Levental
- Department of Integrative Biology and Pharmacology University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Jeffrey T Chang
- Department of Integrative Biology and Pharmacology University of Texas Health Science Center at Houston, Houston, Texas, USA.,School of Biomedical Informatics, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Guangwei Du
- Department of Integrative Biology and Pharmacology University of Texas Health Science Center at Houston, Houston, Texas, USA;
| |
Collapse
|
19
|
Yang K, Dilthey BG, Gross RW. Shotgun Lipidomics Approach to Stabilize the Regiospecificity of Monoglycerides Using a Facile Low-Temperature Derivatization Enabling Their Definitive Identification and Quantitation. Anal Chem 2016; 88:9459-9468. [PMID: 27532157 PMCID: PMC5538723 DOI: 10.1021/acs.analchem.6b01862] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Monoglycerides play a central role in lipid metabolism and are important signaling metabolites. Quantitative analysis of monoglyceride molecular species has remained challenging due to rapid isomerization via α-hydroxy acyl migration. Herein, we describe a shotgun lipidomics approach that utilizes a single-phase methyl tert-butyl ether extraction to minimize acyl migration, a facile low temperature diacetyl derivatization to stabilize regiospecificity, and tandem mass spectrometric analysis to identify and quantify regioisomers of monoglycerides in biological samples. The rapid and robust diacetyl derivatization at low temperatures (e.g., -20 °C, 30 min) prevents postextraction acyl migration and preserves regiospecificity of monoglyceride structural isomers. Furthermore, ionization of ammonium adducts of diacetyl monoglyceride derivatives in positive-ion mode markedly increases analytic sensitivity (low fmol/μL). Critically, diacetyl derivatization enables the differentiation of discrete monoglyceride regioisomers without chromatography through their distinct signature fragmentation patterns during collision induced dissociation. The application of this approach in the analysis of monoglycerides in multiple biologic tissues demonstrated diverse profiles of molecular species. Remarkably, the regiospecificity of individual monoglyceride molecular species is also diverse from tissue to tissue. Collectively, this developed approach enables the profiling, identification and quantitation of monoglyceride regioisomers directly from tissue extracts.
Collapse
Affiliation(s)
- Kui Yang
- Division of Bioorganic Chemistry and Molecular Pharmacology, Departments of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Beverly G. Dilthey
- Division of Bioorganic Chemistry and Molecular Pharmacology, Departments of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Richard W. Gross
- Division of Bioorganic Chemistry and Molecular Pharmacology, Departments of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Developmental Biology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| |
Collapse
|
20
|
Temprano A, Sembongi H, Han GS, Sebastián D, Capellades J, Moreno C, Guardiola J, Wabitsch M, Richart C, Yanes O, Zorzano A, Carman GM, Siniossoglou S, Miranda M. Redundant roles of the phosphatidate phosphatase family in triacylglycerol synthesis in human adipocytes. Diabetologia 2016; 59:1985-94. [PMID: 27344312 PMCID: PMC4969345 DOI: 10.1007/s00125-016-4018-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 05/23/2016] [Indexed: 12/20/2022]
Abstract
AIMS/HYPOTHESIS In mammals, the evolutionary conserved family of Mg(2+)-dependent phosphatidate phosphatases (PAP1), involved in phospholipid and triacylglycerol synthesis, consists of lipin-1, lipin-2 and lipin-3. While mutations in the murine Lpin1 gene cause lipodystrophy and its knockdown in mouse 3T3-L1 cells impairs adipogenesis, deleterious mutations of human LPIN1 do not affect adipose tissue distribution. However, reduced LPIN1 and PAP1 activity has been described in participants with type 2 diabetes. We aimed to characterise the roles of all lipin family members in human adipose tissue and adipogenesis. METHODS The expression of the lipin family was analysed in adipose tissue in a cross-sectional study. Moreover, the effects of lipin small interfering RNA (siRNA)-mediated depletion on in vitro human adipogenesis were assessed. RESULTS Adipose tissue gene expression of the lipin family is altered in type 2 diabetes. Depletion of every lipin family member in a human Simpson-Golabi-Behmel syndrome (SGBS) pre-adipocyte cell line, alters expression levels of adipogenic transcription factors and lipid biosynthesis genes in early stages of differentiation. Lipin-1 knockdown alone causes a 95% depletion of PAP1 activity. Despite the reduced PAP1 activity and alterations in early adipogenesis, lipin-silenced cells differentiate and accumulate neutral lipids. Even combinatorial knockdown of lipins shows mild effects on triacylglycerol accumulation in mature adipocytes. CONCLUSIONS/INTERPRETATION Overall, our data support the hypothesis of alternative pathways for triacylglycerol synthesis in human adipocytes under conditions of repressed lipin expression. We propose that induction of alternative lipid phosphate phosphatases, along with the inhibition of lipid hydrolysis, contributes to the maintenance of triacylglycerol content to near normal levels.
Collapse
Affiliation(s)
- Ana Temprano
- Joan XXIII University Hospital, Pere Virgili Health Research Institut (IISPV), Modular Building, C/ Mallafre Guasch, Tarragona, 43005, Spain
- Department of Biochemistry and Molecular Biology, Rovira i Virgili University, Tarragona, Spain
| | - Hiroshi Sembongi
- Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge, CB2 0XY, UK
- , Chesterford Research Park, Little Chesterford, Saffron Walden, UK
| | - Gil-Soo Han
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition and Health, Rutgers University, New Brunswick, NJ, USA
| | - David Sebastián
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
- Biomedical Research Networking Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Jordi Capellades
- Biomedical Research Networking Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
- Centre for Omic Sciences, Rovira i Virgili University, Reus, Spain
| | - Cristóbal Moreno
- Joan XXIII University Hospital, Pere Virgili Health Research Institut (IISPV), Modular Building, C/ Mallafre Guasch, Tarragona, 43005, Spain
- Biomedical Research Networking Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Juan Guardiola
- Department of Pulmonary, Critical Care and Sleep Medicine, University of Louisville, Louisville, KY, USA
| | - Martin Wabitsch
- Division of Paediatric Endocrinology and Diabetes, Interdisciplinary Obesity Clinic, University Clinic for Child and Adolescent Medicine, University of Ulm, Ulm, Germany
| | - Cristóbal Richart
- Joan XXIII University Hospital, Pere Virgili Health Research Institut (IISPV), Modular Building, C/ Mallafre Guasch, Tarragona, 43005, Spain
- GEMMAIR Research Group - Applied Medicine, Department of Medicine and Surgery, Rovira i Virgili University (URV), Tarragona, Spain
| | - Oscar Yanes
- Biomedical Research Networking Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
- Centre for Omic Sciences, Rovira i Virgili University, Reus, Spain
- Department of Electronic Engineering, Rovira i Virgili University, Tarragona, Spain
| | - Antonio Zorzano
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
- Biomedical Research Networking Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - George M Carman
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition and Health, Rutgers University, New Brunswick, NJ, USA
| | - Symeon Siniossoglou
- Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge, CB2 0XY, UK.
| | - Merce Miranda
- Joan XXIII University Hospital, Pere Virgili Health Research Institut (IISPV), Modular Building, C/ Mallafre Guasch, Tarragona, 43005, Spain.
- Biomedical Research Networking Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain, .
| |
Collapse
|
21
|
Jang CH, Kim KM, Yang JH, Cho SS, Kim SJ, Shin SM, Cho IJ, Ki SH. The Role of Lipin-1 in the Regulation of Fibrogenesis and TGF-β Signaling in Hepatic Stellate Cells. Toxicol Sci 2016; 153:28-38. [PMID: 27345520 DOI: 10.1093/toxsci/kfw109] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The adipogenic transcriptional regulation was reported to inhibit transdifferentiation of hepatic stellate cells (HSCs), which constitute the main fibrogenic cell type in the liver. Lipin-1 exhibits a dual function: an enzyme that catalyzes the conversion of phosphatidate to diacylglycerol and a transcriptional regulator. However, the involvement of Lipin-1 in the regulation of transforming growth factor-β (TGF-β) signaling and fibrogenesis in HSCs is not fully understood. Here, we showed that Lipin-1 was downregulated in activated primary HSCs and TGF-β-treated LX-2 cells, immortalized human HSC cell lines. The downregulation of Lipin-1 by TGF-β was not dependent on altered mRNA stability but rather on protein stability. Treatment of LX-2 cells with the proteasome inhibitor led to the accumulation of Lipin-1. Moreover, we observed a significant increase in Lipin-1 polyubiquitination. Overexpression of Lipin-1 attenuated TGF-β-induced fibrogenic gene expression. In addition, Lipin-1 inhibited TGF-β-mediated activation of Sma and Mad-related family (SMAD), a major transcription factor that transduces intracellular signals from TGF-β. Resveratrol, a well-known natural polyphenolic antioxidant, is known to inhibit liver fibrosis, although its mechanism of action remains unknown. Our data showed that resveratrol significantly increased the levels of Lipin-1 protein and mRNA in HSCs. Further investigation revealed that resveratrol blocked the polyubiquitination of Lipin-1. Resveratrol inhibited TGF-β-induced fibrogenic gene expression. TGF-β-induced SMAD binding element-luciferase reporter activity was significantly diminished by resveratrol with a simultaneous decrease in SMAD3 phosphorylation. Consistently, knockdown of the Lipin-1 gene using siRNA abolished the inhibitory effect of resveratrol. We conclude that Lipin-1 can antagonize HSC activation through the inhibition of TGF-β/SMAD signaling and that resveratrol may affect Lipin-1 gene induction and contribute to the inhibition of TGF-β-mediated hepatic fibrogenesis.
Collapse
Affiliation(s)
- Chang Ho Jang
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea
| | - Kyu Min Kim
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, 08826, Korea
| | - Ji Hye Yang
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea
| | - Sam Seok Cho
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea
| | - Seung Jung Kim
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea
| | - Sang Mi Shin
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea
| | - Il Je Cho
- MRC-GHF, College of Korean Medicine, Daegu Haany University, Gyeongsan, 38610, Korea
| | - Sung Hwan Ki
- *College of Pharmacy, Chosun University, Gwangju, 61452, Korea
| |
Collapse
|
22
|
Adipose tissue deficiency results in severe hyperlipidemia and atherosclerosis in the low-density lipoprotein receptor knockout mice. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:410-8. [PMID: 26921684 DOI: 10.1016/j.bbalip.2016.02.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 02/11/2016] [Accepted: 02/23/2016] [Indexed: 12/17/2022]
Abstract
Adipose tissue can store over 50% of whole-body cholesterol; however, the physiological role of adipose tissue in cholesterol metabolism and atherogenesis has not been directly assessed. Here, we examined lipoprotein metabolism and atherogenesis in a unique mouse model of severe lipodystrophy: the Seipin(-/-) mice, and also in mice deficient in both low-density lipoprotein receptor (Ldlr) and Seipin: the Ldlr(-/-)Seipin(-/-) mice. Plasma cholesterol was moderately increased in the Seipin(-/-) mice when fed an atherogenic diet. Strikingly, plasma cholesterol reached ~6000 mg/dl in the Seipin(-/-)Ldlr(-/-) mice on an atherogenic diet, as compared to ~1000 mg/dl in the Ldlr(-/-) mice on the same diet. The Seipin(-/-)Ldlr(-/-) mice also developed spontaneous atherosclerosis on chow diet and severe atherosclerosis on an atherogenic diet. Rosiglitazone treatment significantly reduced the hypercholesterolemia of the Seipin(-/-)Ldlr(-/-) mice, and also alleviated the severity of atherosclerosis. Our results provide direct evidence, for the first time, that the adipose tissue plays a critical role in the clearance of plasma cholesterol. Our results also reveal a previously unappreciated strong link between adipose tissue and LDLR in plasma cholesterol metabolism.
Collapse
|