1
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Effect of omega-3 ethyl esters on the triglyceride-rich lipoprotein response to endotoxin challenge in healthy young men. J Lipid Res 2023; 64:100353. [PMID: 36907552 PMCID: PMC10123374 DOI: 10.1016/j.jlr.2023.100353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 02/21/2023] [Accepted: 02/25/2023] [Indexed: 03/12/2023] Open
Abstract
Oxylipins are produced enzymatically from polyunsaturated fatty acids, are abundant in triglyceride-rich lipoproteins (TGRL), and mediate inflammatory processes. Inflammation elevates TGRL concentrations, but it is unknown if the fatty acid and oxylipin composition change. In this study, we investigated the effects of prescription ω-3 acid ethyl esters (P-OM3; 3.4 g/d EPA + DHA) on the lipid response to an endotoxin challenge (lipopolysaccharide (LPS); 0.6 ng/kg body weight). Healthy young men (N=17) were assigned 8-12 weeks of P-OM3 and olive oil control in a randomized order crossover study. Following each treatment period, subjects received endotoxin challenge, and the time-dependent TGRL composition was observed. Post-challenge, arachidonic acid (AA) was 16% [95% CI: 4%, 28%] lower than baseline at 8 hours with control. P-OM3 increased TGRL ω-3 fatty acids (EPA 24% [15%, 34%]; DHA 14% [5%, 24%]). The timing of ω-6 oxylipin responses differed by class; AA-derived alcohols peaked at 2 hrs, while linoleic acid (LA)-derived alcohols peaked at 4 hrs (pint = 0.006). P-OM3 increased EPA alcohols by 161% [68%, 305%] and DHA epoxides by 178% [47%, 427%] at 4 hrs compared to control. In conclusion, this study shows that TGRL fatty acid and oxylipin composition changes following endotoxin challenge. P-OM3 alters the TGRL response by increasing availability of ω-3 oxylipins for resolution of the inflammatory response.
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2
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Walker RE, Savinova OV, Pedersen TL, Newman JW, Shearer GC. Effects of inflammation and soluble epoxide hydrolase inhibition on oxylipin composition of very low-density lipoproteins in isolated perfused rat livers. Physiol Rep 2021; 9:e14480. [PMID: 33625776 PMCID: PMC7903942 DOI: 10.14814/phy2.14480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Oxylipins are metabolites of polyunsaturated fatty acids that mediate cardiovascular health by attenuation of inflammation, vascular tone, hemostasis, and thrombosis. Very low-density lipoproteins (VLDL) contain oxylipins, but it is unknown whether the liver regulates their concentrations. In this study, we used a perfused liver model to observe the effect of inflammatory lipopolysaccharide (LPS) challenge and soluble epoxide hydrolase inhibition (sEHi) on VLDL oxylipins. A compartmental model of deuterium-labeled linoleic acid and palmitic acid incorporation into VLDL was also developed to assess the dependence of VLDL oxylipins on fatty acid incorporation rates. LPS decreased the total fatty acid VLDL content by 30% [6%,47%], and decreased final concentration of several oxylipins by a similar amount (13-HOTrE, 35% [4%,55%], -1.3 nM; 9(10)-EpODE, 29% [3%,49%], -2.0 nM; 15(16)-EpODE, 29% [2%,49%], -1.6 nM; AA-derived diols, 32% [5%,52%], -2.4 nM; 19(20)-DiHDPA, 31% [7%,50%], -1.0 nM). However, the EPA-derived epoxide, 17(18)-EpETE, was decreased by 75% [49%,88%], (-0.52 nM) with LPS, double the suppression of other oxylipins. sEHi increased final concentration of DHA epoxide, 16(17)-EpDPE, by 99% [35%,193%], (2.0 nM). Final VLDL-oxylipin concentrations with LPS treatment were not correlated with linoleic acid kinetics, suggesting they were independently regulated under inflammatory conditions. We conclude that the liver regulates oxylipin incorporation into VLDL, and the oxylipin content is altered by LPS challenge and by inhibition of the epoxide hydrolase pathway. This provides evidence for delivery of systemic oxylipin signals by VLDL transport.
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Affiliation(s)
- Rachel E. Walker
- Department of Nutritional SciencesThe Pennsylvania State UniversityUniversity ParkPAUSA
| | - Olga V. Savinova
- Department of Biomedical SciencesNew York Institute of Technology College of Osteopathic MedicineOld WestburyNYUSA
- Sanford ResearchUniversity of South DakotaSioux FallsSDUSA
| | - Theresa L. Pedersen
- Advanced AnalyticsDavisCAUSA
- Department of Food Science and TechnologyUniversity of CaliforniaDavisCAUSA
| | - John W. Newman
- Department of Food Science and TechnologyUniversity of CaliforniaDavisCAUSA
- Obesity and Metabolism Research UnitWestern Human Nutrition Research CenterAgricultural Research ServiceUS Department of AgricultureDavisCAUSA
| | - Gregory C. Shearer
- Department of Nutritional SciencesThe Pennsylvania State UniversityUniversity ParkPAUSA
- Sanford ResearchUniversity of South DakotaSioux FallsSDUSA
- Sanford School of MedicineUniversity of South DakotaSioux FallsSDUSA
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3
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Wu JX, He KY, Zhang ZZ, Qu YL, Su XB, Shi Y, Wang N, Wang L, Han ZG. LZP is required for hepatic triacylglycerol transportation through maintaining apolipoprotein B stability. PLoS Genet 2021; 17:e1009357. [PMID: 33591966 PMCID: PMC7909667 DOI: 10.1371/journal.pgen.1009357] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 02/26/2021] [Accepted: 01/12/2021] [Indexed: 12/12/2022] Open
Abstract
The conserved zona pellucida (ZP) domain is found in hundreds of extracellular proteins that are expressed in various organs and play a variety of roles as structural components, receptors and tumor suppressors. A liver-specific zona pellucida domain-containing protein (LZP), also named OIT3, has been shown to be mainly expressed in human and mouse hepatocytes; however, the physiological function of LZP in the liver remains unclear. Here, we show that Lzp deletion inhibited very low-density lipoprotein (VLDL) secretion, leading to hepatic TG accumulation and lower serum TG levels in mice. The apolipoprotein B (apoB) levels were significantly decreased in the liver, serum, and VLDL particles of LZP-deficient mice. In the presence of LZP, which is localized to the endoplasmic reticulum (ER) and Golgi apparatus, the ER-associated degradation (ERAD) of apoB was attenuated; in contrast, in the absence of LZP, apoB was ubiquitinated by AMFR, a known E3 ubiquitin ligase specific for apoB, and was subsequently degraded, leading to lower hepatic apoB levels and inhibited VLDL secretion. Interestingly, hepatic LZP levels were elevated in mice challenged with a high-fat diet and humans with simple hepatic steatosis, suggesting that LZP contributes to the physiological regulation of hepatic TG homeostasis. In general, our data establish an essential role for LZP in hepatic TG transportation and VLDL secretion by preventing the AMFR-mediated ubiquitination and degradation of apoB and therefore provide insight into the molecular function of LZP in hepatic lipid metabolism.
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Affiliation(s)
- Jiao-Xiang Wu
- Key Laboratory of Systems Biomedicine (Ministry of Education) and Collaborative Innovation Center of Systems Biomedicine of Rui-Jin Hospital, Hongqiao International Institute of Medicine, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China
| | - Kun-Yan He
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Zhuang-Zhuang Zhang
- Key Laboratory of Systems Biomedicine (Ministry of Education) and Collaborative Innovation Center of Systems Biomedicine of Rui-Jin Hospital, Hongqiao International Institute of Medicine, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yu-Lan Qu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xian-Bin Su
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yi Shi
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Na Wang
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Lan Wang
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ze-Guang Han
- Key Laboratory of Systems Biomedicine (Ministry of Education) and Collaborative Innovation Center of Systems Biomedicine of Rui-Jin Hospital, Hongqiao International Institute of Medicine, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China
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4
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Li J, Wang X, Ackerman WE, Batty AJ, Kirk SG, White WM, Wang X, Anastasakis D, Samavati L, Buhimschi I, Nelin LD, Hafner M, Liu Y. Dysregulation of Lipid Metabolism in Mkp-1 Deficient Mice during Gram-Negative Sepsis. Int J Mol Sci 2018; 19:ijms19123904. [PMID: 30563203 PMCID: PMC6321205 DOI: 10.3390/ijms19123904] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 11/27/2018] [Accepted: 11/30/2018] [Indexed: 02/07/2023] Open
Abstract
Mitogen-activated protein kinase phosphatase (Mkp)-1 exerts its anti-inflammatory activities during Gram-negative sepsis by deactivating p38 and c-Jun N-terminal kinase (JNK). We have previously shown that Mkp-1+/+ mice, but not Mkp-1-/- mice, exhibit hypertriglyceridemia during severe sepsis. However, the regulation of hepatic lipid stores and the underlying mechanism of lipid dysregulation during sepsis remains an enigma. To understand the molecular mechanism underlying the sepsis-associated metabolic changes and the role of Mkp-1 in the process, we infected Mkp-1+/+ and Mkp-1-/- mice with Escherichia coli i.v., and assessed the effects of Mkp-1 deficiency on tissue lipid contents. We also examined the global gene expression profile in the livers via RNA-seq. We found that in the absence of E. coli infection, Mkp-1 deficiency decreased liver triglyceride levels. Upon E. coli infection, Mkp-1+/+ mice, but not Mkp-1-/- mice, developed hepatocyte ballooning and increased lipid deposition in the livers. E. coli infection caused profound changes in the gene expression profile of a large number of proteins that regulate lipid metabolism in wildtype mice, while these changes were substantially disrupted in Mkp-1-/- mice. Interestingly, in Mkp-1+/+ mice E. coli infection resulted in downregulation of genes that facilitate fatty acid synthesis but upregulation of Cd36 and Dgat2, whose protein products mediate fatty acid uptake and triglyceride synthesis, respectively. Taken together, our studies indicate that sepsis leads to a substantial change in triglyceride metabolic gene expression programs and Mkp-1 plays an important role in this process.
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Affiliation(s)
- Jinhui Li
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43215, USA.
| | - Xiantao Wang
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Disease, National Institutes of Health, Bethesda, MD 20892, USA.
| | - William E Ackerman
- Department of Obstetrics and Gynecology, The Ohio State University College of Medicine, Columbus, OH 43210, USA.
| | - Abel J Batty
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43215, USA.
| | - Sean G Kirk
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43215, USA.
| | - William M White
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43215, USA.
| | - Xianxi Wang
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43215, USA.
| | - Dimitrios Anastasakis
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Disease, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Lobelia Samavati
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Irina Buhimschi
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43215, USA.
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio 43205, USA.
| | - Leif D Nelin
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43215, USA.
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio 43205, USA.
| | - Markus Hafner
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute of Arthritis and Musculoskeletal and Skin Disease, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Yusen Liu
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43215, USA.
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio 43205, USA.
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5
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Arisqueta L, Navarro-Imaz H, Labiano I, Rueda Y, Fresnedo O. High-fat diet overfeeding promotes nondetrimental liver steatosis in female mice. Am J Physiol Gastrointest Liver Physiol 2018; 315:G772-G780. [PMID: 30095299 DOI: 10.1152/ajpgi.00022.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
High-fat diet (HFD) feeding or leptin-deficient mice are extensively used as models resembling features of human nonalcoholic fatty liver disease (NAFLD). The concurrence of experimental factors as fat content and source or total caloric intake leads to prominent differences in the development of the hepatic steatosis and related disturbances. In this work, we characterized the hepatic lipid accumulation induced by HFD in wild-type (WT) and ob/ ob mice with the purpose of differentiating adaptations to HFD from those specific of increased overfeeding due to leptin deficiency-associated hyperphagia. Given that most published works have been done in male models, we used female mice with the aim of increasing the body of evidence regarding NAFLD in female subjects. HFD promoted liver lipid accumulation only in the hyperphagic strain. Nevertheless, a decrease of lipid droplet-associated cholesteryl ester (CE) in both WT and obese animals was observed. These changes were accompanied by an improvement in the profile of lipoproteins that transport cholesterol and liver function markers in plasma from ob/ ob mice and a lower hepatic index. Using primary hepatocytes from female mice, overaccumulation of CE induced by 0.4 mM oleic acid reversed in the presence of a specific Takeda G protein-coupled bile acid receptor agonist. Nevertheless, hepatocytes from male mice were not responsive. This study suggests that enterohepatic circulation of bile acids might be one of the factors that can affect sex dimorphism in NAFLD development, which underlines the importance of including female models in the NAFLD research field. NEW & NOTEWORTHY This work provides new insight into the use of high-fat diet as a model to induce nonalcoholic fatty liver disease in wild-type and ob/ ob female mice. We show that high-fat diet induces steatosis only in ob/ ob mice while, surprisingly, several health indicators improve. Noteworthy, experiments with primary hepatocytes from male and female mice show that they express Takeda G protein-coupled bile acid receptor and that it and bile acid enterohepatic circulation might be accountable for sex dimorphism in nonalcoholic fatty liver disease development.
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Affiliation(s)
- Lino Arisqueta
- Facultad de Ciencias Naturales y Ambientales, Universidad Internacional SEK , Quito , Ecuador
| | - Hiart Navarro-Imaz
- Lipids and Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Ibone Labiano
- Department of Liver and Gastrointestinal Diseases, Health Research Institute, Biodonostia, Spain
| | - Yuri Rueda
- Lipids and Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Olatz Fresnedo
- Lipids and Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
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6
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Cao Q, Cui X, Wu R, Zha L, Wang X, Parks JS, Yu L, Shi H, Xue B. Myeloid Deletion of α1AMPK Exacerbates Atherosclerosis in LDL Receptor Knockout (LDLRKO) Mice. Diabetes 2016; 65:1565-76. [PMID: 26822081 PMCID: PMC4878417 DOI: 10.2337/db15-0917] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 12/31/2015] [Indexed: 12/28/2022]
Abstract
Macrophage inflammation marks all stages of atherogenesis, and AMPK is a regulator of macrophage inflammation. We therefore generated myeloid α1AMPK knockout (MAKO) mice on the LDL receptor knockout (LDLRKO) background to investigate whether myeloid deletion of α1AMPK exacerbates atherosclerosis. When fed an atherogenic diet, MAKO/LDLRKO mice displayed exacerbated atherosclerosis compared with LDLRKO mice. To determine the underlying pathophysiological pathways, we characterized macrophage inflammation/chemotaxis and lipid/cholesterol metabolism in MAKO/LDLRKO mice. Myeloid deletion of α1AMPK increased macrophage inflammatory gene expression and enhanced macrophage migration and adhesion to endothelial cells. Remarkably, MAKO/LDLRKO mice also displayed higher composition of circulating chemotaxically active Ly-6C(high) monocytes, enhanced atherosclerotic plaque chemokine expression, and monocyte recruitment into plaques, leading to increased atherosclerotic plaque macrophage content and inflammation. MAKO/LDLRKO mice also exhibited higher plasma LDL and VLDL cholesterol content, increased circulating apolipoprotein B (apoB) levels, and higher liver apoB expression. We conclude that macrophage α1AMPK deficiency promotes atherogenesis in LDLRKO mice and is associated with enhanced macrophage inflammation and hypercholesterolemia and that macrophage α1AMPK may serve as a therapeutic target for prevention and treatment of atherosclerosis.
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Affiliation(s)
- Qiang Cao
- Department of Biology and Center for Obesity Reversal, Georgia State University, Atlanta, GA
| | - Xin Cui
- Department of Biology and Center for Obesity Reversal, Georgia State University, Atlanta, GA
| | - Rui Wu
- Department of Biology and Center for Obesity Reversal, Georgia State University, Atlanta, GA
| | - Lin Zha
- Department of Biology and Center for Obesity Reversal, Georgia State University, Atlanta, GA
| | - Xianfeng Wang
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC
| | - John S Parks
- Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC
| | - Liqing Yu
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD
| | - Hang Shi
- Department of Biology and Center for Obesity Reversal, Georgia State University, Atlanta, GA
| | - Bingzhong Xue
- Department of Biology and Center for Obesity Reversal, Georgia State University, Atlanta, GA
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7
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Wang XQ, Wan HQ, Wei XJ, Zhang Y, Qu P. CLI-095 decreases atherosclerosis by modulating foam cell formation in apolipoprotein E-deficient mice. Mol Med Rep 2016; 14:49-56. [PMID: 27176130 PMCID: PMC4918599 DOI: 10.3892/mmr.2016.5233] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 12/18/2015] [Indexed: 12/13/2022] Open
Abstract
Toll-like receptor 4 (TLR4) is considered to have a critical role in the occurrence and development of atherosclerosis in atherosclerosis-prone mice; however, it remains uncertain whether treatment with a TLR4 inhibitor may attenuate atherosclerosis. The present study aimed to determine the vascular protective effects of the TLR4 inhibitor CLI-095 on apolipoprotein E‑deficient (ApoE‑/‑) mice. ApoE‑/‑ mice were fed either chow or a high‑fat diet, and were treated with or without CLI‑095 for 10 weeks. The mean atherosclerotic plaque area in the aortic sections of CLI‑095‑treated mice was 54.3% smaller than in the vehicle‑treated mice (P=0.0051). In vitro, murine peritoneal macrophages were treated with or without CLI‑095, and were subsequently stimulated with oxidized low‑density lipoprotein. Treatment with CLI‑095 markedly reduced the expression levels of lectin‑like oxidized low‑density lipoprotein receptor‑1 and acyl-coenzyme A:cholesterol acyltransferase‑1, and significantly upregulated the expression levels of ATP‑binding cassette transporter A1, predominantly via suppressing activation of the TLR4/nuclear factor‑κB signaling pathway. The results of the present study indicated that the TLR4 inhibitor CLI‑095 has the ability to suppress the progression of atherosclerosis in an in vivo model by reducing macrophage foam cell formation.
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Affiliation(s)
- Xiao-Qing Wang
- Department of Cardiology, Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China
| | - Hui-Qing Wan
- Department of Pharmacy, Dongguan People's Hospital, Dongguan, Guangdong 523000, P.R. China
| | - Xian-Jing Wei
- Department of Cardiology, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning 116023, P.R. China
| | - Ying Zhang
- Department of Cardiology, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning 116023, P.R. China
| | - Peng Qu
- Department of Cardiology, Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China
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8
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Lu Z, Zhang X, Li Y, Jin J, Huang Y. TLR4 antagonist reduces early-stage atherosclerosis in diabetic apolipoprotein E-deficient mice. J Endocrinol 2013; 216:61-71. [PMID: 23060524 DOI: 10.1530/joe-12-0338] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Although it has been reported that deficiency of toll-like receptor 4 (TLR4) is associated with reduced atherosclerosis in atherosclerosis-prone mice and attenuated pro-inflammatory state in diabetic mice, it remains undetermined whether treatment with a TLR4 antagonist reduces atherosclerosis in nondiabetic or diabetic mice that have TLR4 expression. In this study, we determined the effect of Rhodobacter sphaeroides lipopolysaccharide (Rs-LPS), an established TLR4 antagonist, on early-stage atherosclerosis in nondiabetic and streptozotocin-induced diabetic apolipoprotein E-deficient (Apoe(-/-)) mice. Analysis of atherosclerotic lesions of both en face aortas and cross sections of aortic roots showed that administration of Rs-LPS in 14-week-old diabetic Apoe(-/-) mice for 10 weeks significantly reduced atherosclerotic lesions. Although atherosclerotic lesions in nondiabetic Apoe(-/-) mice appeared to be decreased by Rs-LPS treatment, the difference was not statistically significant. Metabolic study showed that Rs-LPS significantly lowered serum levels of cholesterol and triglycerides in nondiabetic mice but not in diabetic mice. Furthermore, immunohistochemistry studies showed that Rs-LPS inhibited the expression of interleukin 6 and matrix metalloproteinase-9 and reduced the content of monocytes and macrophages in atherosclerotic plaques. Taken together, this study demonstrated for the first time that TLR4 antagonist inhibited vascular inflammation and atherogenesis in diabetic Apoe(-/-) mice and lowered serum cholesterol and triglyceride levels in nondiabetic Apoe(-/-) mice.
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MESH Headings
- Animals
- Anti-Inflammatory Agents, Non-Steroidal/metabolism
- Anti-Inflammatory Agents, Non-Steroidal/pharmacology
- Anti-Inflammatory Agents, Non-Steroidal/therapeutic use
- Aorta/drug effects
- Aorta/immunology
- Aorta/pathology
- Apolipoproteins E/genetics
- Apolipoproteins E/metabolism
- Atherosclerosis/drug therapy
- Atherosclerosis/immunology
- Atherosclerosis/pathology
- Atherosclerosis/physiopathology
- Cell Line
- Cells, Cultured
- Cytokines/genetics
- Cytokines/metabolism
- Diabetes Mellitus, Type 1/complications
- Diabetic Angiopathies/drug therapy
- Diabetic Angiopathies/immunology
- Diabetic Angiopathies/pathology
- Diabetic Angiopathies/physiopathology
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/immunology
- Endothelium, Vascular/metabolism
- Humans
- Hyperlipidemias/prevention & control
- Leukocytes, Mononuclear/drug effects
- Leukocytes, Mononuclear/immunology
- Leukocytes, Mononuclear/metabolism
- Lipopolysaccharides/metabolism
- Lipopolysaccharides/pharmacology
- Lipopolysaccharides/therapeutic use
- Male
- Mice
- Mice, Knockout
- Plaque, Atherosclerotic/etiology
- Plaque, Atherosclerotic/prevention & control
- Random Allocation
- Recombinant Proteins/metabolism
- Rhodobacter sphaeroides/metabolism
- Toll-Like Receptor 4/antagonists & inhibitors
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Affiliation(s)
- Zhongyang Lu
- Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC 29401, USA
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9
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Bartolomé N, Aspichueta P, Martínez MJ, Vázquez-Chantada M, Martínez-Chantar ML, Ochoa B, Chico Y. Biphasic adaptative responses in VLDL metabolism and lipoprotein homeostasis during Gram-negative endotoxemia. Innate Immun 2010; 18:89-99. [PMID: 21113081 DOI: 10.1177/1753425910390722] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Dyslipidemia and hepatic overproduction of very low density lipoprotein (VLDL) are hallmarks of the septic response, yet the underlying mechanisms are not fully defined. We evaluated the lipoprotein subclasses profile and hepatic VLDL assembly machinery over 24 h in fasted LPS-treated rats. The response of serum non-esterified fatty acids (NEFA) and glucose to endotoxin was biphasic, with increased levels of NEFA and hypoglycemia in the first 12 h-phase, and low NEFA and high glucose in the second 12 h-phase. Hypertriglyceridemia was more marked in the first 12 h (6.8-fold), when triglyceride abundance increased in all lipoprotein subclasses, and preferentially in large VLDL. The abundance of medium-sized VLDL and the increase in the number of VLDL particles was higher in the second phase (10-fold vs 5-fold in the first phase); however, apoB gene transcript abundance increased only in the second phase. Analysis of putative pre-translational mechanisms revealed that neither increased Apob transcription rate nor increased transcript binding to mRNA stabilizing HuR (Hu antigen R) protein paralleled the increase in apoB transcripts. In conclusion, endotoxin challenge induces increases in plasma NEFA and large, triglyceride-rich VLDL. After approximately 12 h, the triglyceride-rich VLDLs are replaced by medium-sized, triglyceride-poor VLDL particles. Hepatic apoB mRNA abundance also increases during the second period, suggesting a role for apoB protein expression in the acute reaction against sepsis.
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Affiliation(s)
- Nerea Bartolomé
- Department of Physiology, Faculty of Medicine and Dentistry, University of Basque Country, Leioa, Spain
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10
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Bartolomé N, Arteta B, Martínez MJ, Chico Y, Ochoa B. Kupffer cell products and interleukin 1beta directly promote VLDL secretion and apoB mRNA up-regulation in rodent hepatocytes. Innate Immun 2009; 14:255-66. [PMID: 18669611 DOI: 10.1177/1753425908094718] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Plasma VLDL accumulation in Gram-negative sepsis is partly ascribed to an increased hepatic VLDL production driven by pro-inflammatory cytokines. We previously showed that hepatocytes of the Kupffer cell (KC)-rich periportal area are major contributors to enhanced VLDL production in lipopolysaccharide (LPS)-injected rats. However, it remains to be established whether KC generated products directly affect the number (apoB) and composition of secreted VLDL. Using rat primary cells, we show here that hepatocytes respond to stimulation by soluble mediators released by LPS-stimulated Kupffer cells with enhanced secretion of apoB and triglycerides in phospholipid-rich VLDL particles. Unstimulated KC products also augmented the secretion of normal VLDL, doubling apoB mRNA abundance. IL-1beta treatment resulted in concentration-dependent increases of hepatocyte apoB mRNA and protein secretion, increases that were greater, but not additive, when combined with IL-6 and TNF-alpha. Lipid secretion and MTP mRNA levels were unaffected by cytokines. In summary: (i) enhanced secretion of phospholipid-rich VLDL particles is a net hepatocyte response to LPS-stimulated KC products, which gives a clue about the local role of Kupffer cells in septic dyslipidemia induction; and (ii) pro-inflammatory cytokines act redundantly to enhance apoB secretion involving translational apoB up-regulation, but other humoral components or KC mediators are necessary to accomplish increased lipid association.
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Affiliation(s)
- Nerea Bartolomé
- Department of Physiology, Faculty of Medicine, University of the Basque Country, Leioa, Spain
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Bartolomé N, Rodríguez L, Martínez MJ, Ochoa B, Chico Y. Upregulation of apolipoprotein B secretion, but not lipid, by tumor necrosis factor-alpha in rat hepatocyte cultures in the absence of extracellular fatty acids. Ann N Y Acad Sci 2007; 1096:55-69. [PMID: 17405916 DOI: 10.1196/annals.1397.070] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Tumor necrosis factor-alpha (TNF-alpha) plays a pivotal role in the host response to infection. Rapidly liberated to the bloodstream, TNF-alpha triggers the production of other cytokines and the acute-phase response. Hypertriglyceridemia is a sepsis hallmark associated with high plasma levels of very low-density lipoprotein (VLDL) particles, partly ascribed to increased hepatic production. The kinetics of the hepatocyte response, the cytokine/s responsible, and the underlying mechanisms are not fully elucidated. VLDL biogenesis is a complex, time-consuming process that depends on lipid availability and microsomal triglyceride transfer protein (MTP) activity for correct apolipoprotein B (apoB) lipidation. Studies were performed to define the direct effect of TNF-alpha on VLDL secretion rate and composition in rat hepatocytes cultured in conditions resembling the fed situation. Increases of 17-24% in the number of VLDL particles secreted and of 44-88% in the cellular levels of apoB mRNA were caused by 5, 20, or 100 ng/mL TNF-alpha in 8 h. Lipoprotein secretion returned to baseline levels in 16 h, whereas TNF-alpha-treated cells continued to exhibit higher apoB transcript levels. The mass of each lipid class in secreted VLDL and of MTP mRNA in cells was not affected by any of the tested TNF-alpha doses or treatment periods. These findings indicate that over a wide range of concentrations, TNF-alpha was capable of inducing sustained upregulation of apoB mRNA expression and transient increase in secretion of its protein, but, apparently, VLDL triglyceride secretion was not a TNF-alpha target under conditions in which fatty acids were not extracellularly provided.
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Affiliation(s)
- Nerea Bartolomé
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Sarriena s/n, 48940-Leioa, Spain
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