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Han H, Zhang JM, Ji S, Zeng XB, Jin XC, Shen ZQ, Xie B, Luo XN, Li K, Liu LP. Histology and transcriptomic analysis reveal the inflammation and affected pathways under 2-methylisoborneol (2-MIB) exposure on grass carp. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 938:173233. [PMID: 38763196 DOI: 10.1016/j.scitotenv.2024.173233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 03/19/2024] [Accepted: 05/12/2024] [Indexed: 05/21/2024]
Abstract
2-Methylisoborneol (2-MIB) is a common and widely distributed off-flavor compound in water. However, the toxic mechanisms of 2-MIB on aquatic organisms remain largely unexplored. In this study, grass carp larvae were exposed to different concentrations (0, 5, and 20 μg L-1) of 2-MIB for 96 h. The accumulation of 2-MIB in the dorsal muscle was measured. Histological analysis, ultrastructure observations, and transcriptomic sequencing were conducted on the liver tissues. The results showed that 2-MIB accumulated significantly in the fish muscle, with the accumulation increasing as the exposure concentration increased through gas chromatography-mass spectrometry (GC-MS) detection. Histological and ultrastructure observations indicated that 2-MIB caused concentration-dependent inflammatory infiltration and mitochondrial damage in the liver. Transcriptomic analysis revealed lipid metabolism disorders induced by exposure to 2-MIB in grass carp. Additionally, 5 μg L-1 2-MIB affected the neurodevelopment and cardiovascular system of grass carp larvae through extracellular matrix (ECM)-receptor interaction and focal adhesion pathway. Furthermore, several pathways related to the digestive system were significantly enriched, implying that 2-MIB may impact pancreatic secretion function, protein digestion and absorption processes. These findings provide new insights into the potential toxicological mechanisms of 2-MIB.
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Affiliation(s)
- Huan Han
- China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology (Shanghai), Shanghai Ocean University, Shanghai 201306, China
| | - Jun-Ming Zhang
- China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology (Shanghai), Shanghai Ocean University, Shanghai 201306, China
| | - Shuang Ji
- China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology (Shanghai), Shanghai Ocean University, Shanghai 201306, China
| | - Xiang-Biao Zeng
- China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology (Shanghai), Shanghai Ocean University, Shanghai 201306, China
| | - Xi-Chen Jin
- China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology (Shanghai), Shanghai Ocean University, Shanghai 201306, China
| | - Zi-Qian Shen
- China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology (Shanghai), Shanghai Ocean University, Shanghai 201306, China
| | - Bin Xie
- China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology (Shanghai), Shanghai Ocean University, Shanghai 201306, China
| | - Xue-Neng Luo
- China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology (Shanghai), Shanghai Ocean University, Shanghai 201306, China
| | - Kang Li
- China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology (Shanghai), Shanghai Ocean University, Shanghai 201306, China; Center for Ecological Aquaculture (CEA), Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai 201306, China.
| | - Li-Ping Liu
- China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology (Shanghai), Shanghai Ocean University, Shanghai 201306, China; Center for Ecological Aquaculture (CEA), Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai 201306, China.
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Delrue C, Dendooven A, Vandendriessche A, Speeckaert R, De Bruyne S, Speeckaert MM. Advancing Renal Amyloidosis Care: The Role of Modern Diagnostic Techniques with the Potential of Enhancing Patient Outcomes. Int J Mol Sci 2024; 25:5875. [PMID: 38892061 PMCID: PMC11172584 DOI: 10.3390/ijms25115875] [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: 04/30/2024] [Revised: 05/24/2024] [Accepted: 05/28/2024] [Indexed: 06/21/2024] Open
Abstract
Renal amyloidosis is a set of complex disorders characterized by the deposition of amyloid proteins in the kidneys, which causes gradual organ damage and potential kidney failure. Recent developments in diagnostic methods, particularly mass spectrometry and proteome profiling, have greatly improved the accuracy of amyloid typing, which is critical for disease management. These technologies provide extensive insights into the specific proteins involved, allowing for more targeted treatment approaches and better patient results. Despite these advances, problems remain, owing to the heterogeneous composition of amyloid proteins and the varying efficacy of treatments based on amyloid type. Access to sophisticated diagnostics and therapy varies greatly, highlighting the global difference in renal amyloidosis management. Future research is needed to investigate next-generation sequencing and gene-editing technologies, like clustered regularly interspaced short palindromic repeats (CRISPR), which promise more profound insights into the genetic basis of amyloidosis.
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Affiliation(s)
- Charlotte Delrue
- Department of Nephrology, Ghent University Hospital, 9000 Ghent, Belgium;
| | - Amélie Dendooven
- Department of Pathology, Ghent University Hospital, 9000 Ghent, Belgium; (A.D.); (A.V.)
- Faculty of Medicine, University of Antwerp, 2610 Wilrijk, Belgium
| | | | | | - Sander De Bruyne
- Department of Laboratory Medicine, Ghent University Hospital, 9000 Ghent, Belgium;
| | - Marijn M. Speeckaert
- Department of Nephrology, Ghent University Hospital, 9000 Ghent, Belgium;
- Research Foundation-Flanders (FWO), 1000 Brussels, Belgium
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Kozan DW, Derrick JT, Ludington WB, Farber SA. From worms to humans: Understanding intestinal lipid metabolism via model organisms. Biochim Biophys Acta Mol Cell Biol Lipids 2023; 1868:159290. [PMID: 36738984 PMCID: PMC9974936 DOI: 10.1016/j.bbalip.2023.159290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 01/10/2023] [Accepted: 01/19/2023] [Indexed: 02/05/2023]
Abstract
The intestine is responsible for efficient absorption and packaging of dietary lipids before they enter the circulatory system. This review provides a comprehensive overview of how intestinal enterocytes from diverse model organisms absorb dietary lipid and subsequently secrete the largest class of lipoproteins (chylomicrons) to meet the unique needs of each animal. We discuss the putative relationship between diet and metabolic disease progression, specifically Type 2 Diabetes Mellitus. Understanding the molecular response of intestinal cells to dietary lipid has the potential to undercover novel therapies to combat metabolic syndrome.
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Affiliation(s)
- Darby W Kozan
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States; Department of Embryology, Carnegie Institute for Science, Baltimore, MD, United States
| | - Joshua T Derrick
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States; Department of Embryology, Carnegie Institute for Science, Baltimore, MD, United States
| | - William B Ludington
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States; Department of Embryology, Carnegie Institute for Science, Baltimore, MD, United States
| | - Steven A Farber
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States; Department of Embryology, Carnegie Institute for Science, Baltimore, MD, United States.
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4
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Duman T, Akyüz E, Bulut H, Koçyiğit A, Tülek A, Karataş E, Kırpınar İ. Investigation of Diagnostic Proteins by 2D Electrophoresis in Major Depression Model Induced by Forced Swim Test in Rats. Protein Pept Lett 2021; 28:195-204. [PMID: 32729412 DOI: 10.2174/0929866527999200729183729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Aside from its pervasiveness, whereby it affects as much as 20% of the world's population, depression continues to be one of the most crucial psychiatric problems due to the loss of power it causes by disrupting daily life functioning, containing economic consequences, and having a high suicidal tendency. Major depression (MD) is a systemic and multifactorial disorder involving complex interactions between genetic predisposition and disturbances of various molecular pathways. OBJECTIVES In our current study, we aimed to identify the proteins obtained from serum samples that change during depression with the MD model. METHODS The MD model was applied through the forced swim test in rats. 14 Winstar Albino male rats were divided into two equal groups as follows: depression and control groups. Serum samples were separated by chromatographic methods and then compared with two-dimensional (2D) electrophoresis. RESULTS A total of 9 potential diagnostic protein sequences were identified, which were distinguished with computer software. During the last phase of the study, the Matrix-Assisted Laser Desorption/ Ionization - Time of Flight (MALDI-TOF) analysis, the previous expression sequences identified among the groups were determined and classified. By comparing protein expressions, it was concluded that 9 different points could be used together as a potential biomarker. CONCLUSION Results can help us identify a new diagnostic system that can be used to diagnose MD.
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Affiliation(s)
- Tuğçe Duman
- Department of Neuroscience, Institute of Health, Bezmialem Vakıf University, Istanbul, Turkey
| | - Enes Akyüz
- Department of Biophysics, Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Huri Bulut
- Department of Medical Biochemistry, Faculty of Medicine, Istinye University, Istanbul, Turkey
| | - Abdurrahim Koçyiğit
- Department of Medical Biochemistry, Faculty of Medicine Bezmialem Vakıf University, Istanbul, Turkey
| | - Ahmet Tülek
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Turkey
| | - Ersin Karataş
- Department of Molecular Biology and Genetics, Gebze Technical University, Gebze, Turkey
| | - İsmet Kırpınar
- Department of Psychiatry, Faculty of Medicine, Bezmialem Vakıf University, Istanbul, Turkey
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Siemienowicz KJ, Filis P, Shaw S, Douglas A, Thomas J, Mulroy S, Howie F, Fowler PA, Duncan WC, Rae MT. Fetal androgen exposure is a determinant of adult male metabolic health. Sci Rep 2019; 9:20195. [PMID: 31882954 PMCID: PMC6934666 DOI: 10.1038/s41598-019-56790-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 12/17/2019] [Indexed: 12/13/2022] Open
Abstract
Androgen signalling is a critical driver of male development. Fetal steroid signalling can be dysregulated by a range of environmental insults and clinical conditions. We hypothesised that poor adult male health was partially attributable to aberrant androgen exposure during development. Testosterone was directly administered to developing male ovine fetuses to model excess prenatal androgenic overexposure associated with conditions such as polycystic ovary syndrome (PCOS). Such in utero androgen excess recreated the dyslipidaemia and hormonal profile observed in sons of PCOS patients. 1,084 of 15,134 and 408 of 2,766 quantifiable genes and proteins respectively, were altered in the liver during adolescence, attributable to fetal androgen excess. Furthermore, prenatal androgen excess predisposed to adolescent development of an intrahepatic cholestasis-like condition with attendant hypercholesterolaemia and an emergent pro-fibrotic, pro-oxidative stress gene and protein expression profile evident in both liver and circulation. We conclude that prenatal androgen excess is a previously unrecognised determinant of lifelong male metabolic health.
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Affiliation(s)
| | - Panagiotis Filis
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, AB25 2ZD, UK
| | - Sophie Shaw
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, AB25 2ZD, UK
| | - Alex Douglas
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, AB25 2ZD, UK
| | - Jennifer Thomas
- School of Applied Science, Edinburgh Napier University, Edinburgh, EH11 4BN, UK
| | - Sally Mulroy
- School of Applied Science, Edinburgh Napier University, Edinburgh, EH11 4BN, UK
| | - Forbes Howie
- MRC Centre for Reproductive Health, The University of Edinburgh, Edinburgh, EH16 4TJ, UK
| | - Paul A Fowler
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen, AB25 2ZD, UK
| | - W Colin Duncan
- MRC Centre for Reproductive Health, The University of Edinburgh, Edinburgh, EH16 4TJ, UK
| | - Mick T Rae
- School of Applied Science, Edinburgh Napier University, Edinburgh, EH11 4BN, UK.
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Wang Z, Wang L, Zhang Z, Feng L, Song X, Wu J. Apolipoprotein A-IV involves in glucose and lipid metabolism of rat. Nutr Metab (Lond) 2019; 16:41. [PMID: 31303888 PMCID: PMC6604154 DOI: 10.1186/s12986-019-0367-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/06/2019] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Apolipoprotein A-IV (ApoA-IV) exists in relatively high levels in the circulation systems of animals, but its roles are not fully elucidated. It is known that the Apoa4 gene resides in the cluster Apoa1/Apoc3/Apoa4. Because of a short intergenic sequence between Apoc3 and Apoa4, a previous ApoA-IV knockout mouse model by gene targeting had an accompanying deficiency in ApoC-III expression, which limited its application in investigating the precise roles of ApoA-IV. To solve this problem, we created a specific knockout of ApoA-IV in Sprague-Dawlay rats by TALEN approach. METHODS Age-matched knockout rats and their wild-type littermate controls maintained on a standard rodent diet were studied and blood metabolic parameters were measured. Glucose, insulin, olive oil, and intralipid tolerance tests were performed to study the glucose and lipid metabolism of rats. Quantitative real-time PCR and RNA-seq analysis in liver and inguinal white adipose tissue (iWAT) of rats at three ages (18 weeks, 45 weeks and 90 weeks) were performed to identify the genes altered by ApoA-IV knockout. RESULTS ApoA-IV knockout rats were apparently normal and fertile, but exhibited improved glucose clearance when challenged with glucose tolerance test. In addition, fasting-induced hepatic steatosis was more pronounced in ApoA-IV knockout rats. Further analysis identified that a set of hepatic genes involved in glycolysis, gluconeogenesis and de novo lipogenesis were altered in the absence of ApoA-IV, which induced enhanced glycolysis, attenuated gluconeogenesis and elevated de novo lipogenesis. And the RNA-seq results also confirmed that almost all the genes mentioned in the phenotyping section were highly consistent throughout the three studied ages. CONCLUSIONS ApoA-IV functions in an age-independent manner in the modulation of glucose and lipid metabolism of rats, and may serve as a potential linker between hepatic glucose and lipid metabolism.
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Affiliation(s)
- Zhenguo Wang
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031 China
| | - Lu Wang
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031 China
| | - Zhuzhen Zhang
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031 China
| | - Li Feng
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031 China
| | - Xue Song
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031 China
- School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai, 201210 China
| | - Jiarui Wu
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031 China
- School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai, 201210 China
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Wang X, Gong Y, Deng T, Zhang L, Liao X, Han C, Yang C, Huang J, Wang Q, Song X, Zhang T, Yu T, Zhu G, Ye X, Peng T. Diagnostic and prognostic significance of mRNA expressions of apolipoprotein A and C family genes in hepatitis B virus-related hepatocellular carcinoma. J Cell Biochem 2019; 120:18246-18265. [PMID: 31211449 DOI: 10.1002/jcb.29131] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 01/17/2023]
Abstract
BACKGROUND Hepatocellular carcinoma (HCC) is among the most common and lethal malignancies worldwide. Apolipoproteins (APOs) have been reported increasingly for their relationships with tumors. We aim at exploring the potential relationships of apolipoprotein A (APOA) and apolipoprotein C (APOC) family members with HCC. METHODS A data set, containing 212 hepatitis B virus-related HCC patients, was used for analysis. The diagnostic and prognostic ability of APOA and APOC family genes was figured out. Risk score models and nomograms were developed for the HCC prognosis prediction. Moreover, molecular mechanism exploration were identified biological processes and metabolic pathways of these genes involved in. Validation analysis was carried out using online website. RESULTS APOA1, APOC1, APOC3, and APOC4 showed robust diagnosis significance (all P < 0.05). APOA4, APOC3, and APOC4 were associated with the overall survival (OS) while APOA4 and APOC4 were linked to recurrence-free survival (RFS, all P ≤ 0.05). Risk score models and nomograms had the advantage of predicting OS and RFS for HCC. Molecular mechanism exploration indicated that these genes were involved in the steroid metabolic process, the PPAR signaling pathway, and fatty acid metabolism. Besides that, validation analysis revealed that APOC1 and APOC4 had an association with OS; and APOC3 was associated with OS and RFS (all P ≤ 0.05). CONCLUSIONS APOA1, APOC1, APOC3, and APOC4 are likely to be potential diagnostic biomarkers and APOC3 and APOC4 are likely to be potential prognostic biomarkers for hepatitis B virus-related HCC. They may be involved in the steroid metabolic process, PPAR signaling pathway, and fatty acid metabolism.
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Affiliation(s)
- Xiangkun Wang
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Yizhen Gong
- Department of Colorectal and Anal Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Teng Deng
- Department of Neurosurgery, Affiliated Tumor Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Linbo Zhang
- Department of Health Management and Division of Physical Examination, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Xiwen Liao
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Chuangye Han
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Chengkun Yang
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Jianlu Huang
- Department of Hepatobiliary Surgery, The Third Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Qiaoqi Wang
- Department of Medical Cosmetology, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Xiaowei Song
- Department of Gastrointestinal Glands, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Tengfang Zhang
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Tingdong Yu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Guangzhi Zhu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Xinping Ye
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Tao Peng
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
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β-Casomorphin increases fat deposition in broiler chickens by modulating expression of lipid metabolism genes. Animal 2018; 13:777-783. [PMID: 30139413 DOI: 10.1017/s1751731118002197] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
β-Casomorphin is an opioid-like bioactive peptide derived from β-casein of milk that plays a crucial role in modulating animal's feed intake, growth, nutrient utilization and immunity. However, the effect of β-casomorphin on lipid metabolism in chickens and its mechanism remain unclear. The aim of this study was to investigate the effects of β-casomorphin on fat deposition in broiler chickens and explore its mechanism of action. A total of 120 21-day-old Arbor Acres male broilers (747.94±8.85 g) was chosen and randomly divided into four groups with six replicates of five birds per replicate. Three groups of broilers were injected with 0.1, 0.5 or 1.0 mg/kg BW of β-casomorphin in 1 ml saline for 7 days, whereas the control group received 1 ml saline only. The results showed that subcutaneous administration of β-casomorphin to broiler chickens increased average daily gain, average daily feed intake and fat deposition, and decreased feed : gain ratio (P<0.05). The activity of malate dehydrogenase in the pectoral muscle, liver and abdominal adipose tissue was also increased along with the concentrations of insulin, very-low-density lipoprotein and triglyceride in the plasma (P<0.05). The activity of hormone-sensitive lipase in the liver and abdominal adipose tissue and the concentration of glucagon in the plasma were decreased by injection with β-casomorphin (P<0.05). Affymetrix gene chip analysis revealed that administering 1.0 mg/kg BW β-casomorphin caused differential expression of 168 genes in the liver with a minimum of fourfold difference. Of those, 37 genes are directly involved in lipid metabolism with 18 up-regulated genes such as very low density lipoprotein receptor gene and fatty acid synthase gene, and 19 down-regulated genes such as lipoprotein lipase gene and low density lipoprotein receptor gene. In conclusion, β-casomorphin increased growth performance and fat deposition of broilers. Regulation of fat deposition by β-casomorphin appears to take place through changes in hormone secretion and enzyme activities by controlling the gene expression of lipid metabolism and feed intake, increasing fat synthesis and deposition.
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CREBH Regulates Systemic Glucose and Lipid Metabolism. Int J Mol Sci 2018; 19:ijms19051396. [PMID: 29738435 PMCID: PMC5983805 DOI: 10.3390/ijms19051396] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 04/30/2018] [Accepted: 05/06/2018] [Indexed: 12/23/2022] Open
Abstract
The cyclic adenosine monophosphate (cAMP)-responsive element-binding protein H (CREBH, encoded by CREB3L3) is a membrane-bound transcriptional factor that primarily localizes in the liver and small intestine. CREBH governs triglyceride metabolism in the liver, which mediates the changes in gene expression governing fatty acid oxidation, ketogenesis, and apolipoproteins related to lipoprotein lipase (LPL) activation. CREBH in the small intestine reduces cholesterol transporter gene Npc1l1 and suppresses cholesterol absorption from diet. A deficiency of CREBH in mice leads to severe hypertriglyceridemia, fatty liver, and atherosclerosis. CREBH, in synergy with peroxisome proliferator-activated receptor α (PPARα), has a crucial role in upregulating Fgf21 expression, which is implicated in metabolic homeostasis including glucose and lipid metabolism. CREBH binds to and functions as a co-activator for both PPARα and liver X receptor alpha (LXRα) in regulating gene expression of lipid metabolism. Therefore, CREBH has a crucial role in glucose and lipid metabolism in the liver and small intestine.
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Differential protein analysis of serum exosomes post-intravenous immunoglobulin therapy in patients with Kawasaki disease. Cardiol Young 2017; 27:1786-1796. [PMID: 28803590 DOI: 10.1017/s1047951117001433] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Kawasaki disease, which is characterised by systemic vasculitides accompanied by acute fever, is regularly treated by intravenous immunoglobulin to avoid lesion formation in the coronary artery; however, the mechanism of intravenous immunoglobulin therapy is unclear. Hence, we aimed to analyse the global expression profile of serum exosomal proteins before and after administering intravenous immunoglobulin. METHODS Two-dimensional electrophoresis coupled with mass spectrometry analysis was used to identify the differentially expressed proteome of serum exosomes in patients with Kawasaki disease before and after intravenous immunoglobulin therapy. RESULTS Our analysis revealed 69 differential protein spots in the Kawasaki disease group with changes larger than 1.5-fold and 59 differential ones in patients after intravenous immunoglobulin therapy compared with the control group. Gene ontology analysis revealed that the acute-phase response disappeared, the functions of the complement system and innate immune response were enhanced, and the antibacterial humoral response pathway of corticosteroids and cardioprotection emerged after administration of intravenous immunoglobulin. Further, we showed that complement C3 and apolipoprotein A-IV levels increased before and decreased after intravenous immunoglobulin therapy and that the insulin-like growth factor-binding protein complex acid labile subunit displayed reverse alteration before and after intravenous immunoglobulin therapy. These observations might be potential indicators of intravenous immunoglobulin function. CONCLUSIONS Our results show the differential proteomic profile of serum exosomes of patients with Kawasaki disease before and after intravenous immunoglobulin therapy, such as complement C3, apolipoprotein A-IV, and insulin-like growth factor-binding protein complex acid labile subunit. These results may be useful in the identification of markers for monitoring intravenous immunoglobulin therapy in patients with Kawasaki disease.
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11
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Cheng D, Xu X, Simon T, Boudyguina E, Deng Z, VerHague M, Lee AH, Shelness GS, Weinberg RB, Parks JS. Very Low Density Lipoprotein Assembly Is Required for cAMP-responsive Element-binding Protein H Processing and Hepatic Apolipoprotein A-IV Expression. J Biol Chem 2016; 291:23793-23803. [PMID: 27655915 DOI: 10.1074/jbc.m116.749283] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Indexed: 12/21/2022] Open
Abstract
Hepatic apolipoprotein A-IV (apoA-IV) expression is correlated with hepatic triglyceride (TG) content in mouse models of chronic hepatosteatosis, and steatosis-induced hepatic apoA-IV gene expression is regulated by nuclear transcription factor cAMP-responsive element-binding protein H (CREBH) processing. To define what aspects of TG homeostasis regulate hepatic CREBH processing and apoA-IV gene expression, several mouse models of attenuated VLDL particle assembly were subjected to acute hepatosteatosis induced by an overnight fast or short term ketogenic diet feeding. Compared with chow-fed C57BL/6 mice, fasted or ketogenic diet-fed mice displayed increased hepatic TG content, which was highly correlated (r2 = 0.95) with apoA-IV gene expression, and secretion of larger, TG-enriched VLDL, despite a lower rate of TG secretion and a similar or reduced rate of apoB100 secretion. When VLDL particle assembly and secretion was inhibited by hepatic shRNA-induced apoB silencing or genetic or pharmacologic reduction in microsomal triglyceride transfer protein (MTP) activity, hepatic TG content increased dramatically; however, CREBH processing and apoA-IV gene expression were attenuated compared with controls. Adenovirus-mediated reconstitution of MTP expression proportionately restored CREBH processing and apoA-IV expression in liver-specific MTP knock-out mice. These results reveal that hepatic TG content, per se, does not regulate CREBH processing. Instead, TG mobilization into the endoplasmic reticulum for nascent VLDL particle assembly activates CREBH processing and enhances apoA-IV gene expression in the setting of acute steatosis. We conclude that VLDL assembly and CREBH activation play key roles in the response to hepatic steatosis by up-regulating apoA-IV and promoting assembly and secretion of larger, more TG-enriched VLDL particles.
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Affiliation(s)
- Dongmei Cheng
- From the Departments of Internal Medicine-Section on Molecular Medicine
| | - Xu Xu
- the Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, New York 10065
| | - Trang Simon
- Internal Medicine-Section on Gastroenterology
| | - Elena Boudyguina
- From the Departments of Internal Medicine-Section on Molecular Medicine
| | | | - Melissa VerHague
- From the Departments of Internal Medicine-Section on Molecular Medicine
| | - Ann-Hwee Lee
- the Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, New York 10065
| | | | | | - John S Parks
- From the Departments of Internal Medicine-Section on Molecular Medicine, .,Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157 and
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De Santis C, Taylor JF, Martinez-Rubio L, Boltana S, Tocher DR. Influence of Development and Dietary Phospholipid Content and Composition on Intestinal Transcriptome of Atlantic Salmon (Salmo salar). PLoS One 2015; 10:e0140964. [PMID: 26488165 PMCID: PMC4619195 DOI: 10.1371/journal.pone.0140964] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/25/2015] [Indexed: 11/19/2022] Open
Abstract
The inclusion of intact phospholipids in the diet is essential during larval development and can improve culture performance of many fish species. The effects of supplementation of dietary phospholipid from marine (krill) or plant (soy lecithin) sources were investigated in Atlantic salmon, Salmo salar. First feeding fry were fed diets containing either krill oil or soybean lecithin supplying phospholipid at 2.6%, 3.2%, 3.6% and 4.2% of diet. Fish were sampled at ~ 2.5 g (~1,990°day post fertilization, dpf) and ~10 g (2,850°dpf). By comparison of the intestinal transcriptome in specifically chosen contrasts, it was determined that by 2,850°dpf fish possessed a profile that resembled that of mature and differentiated intestinal cell types with a number of changes specific to glycerophospholipid metabolism. It was previously shown that intact phospholipids and particularly phosphatidylcholine are essential during larval development and that this requirement is associated with the inability of enterocytes in young fry to endogenously synthesize sufficient phospholipid for the efficient export of dietary lipid. In the immature phase (~1,990°dpf), the dietary phospholipid content as well as its class composition impacted on several biochemical and morphological parameters including growth, but these differences were not associated with differences in intestinal transcriptomes. The results of this study have made an important contribution to our understanding of the mechanisms associated with lipid transport and phospholipid biosynthesis in early life stages of fish.
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Affiliation(s)
- Christian De Santis
- Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, United Kingdom
- * E-mail:
| | - John F. Taylor
- Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, United Kingdom
| | - Laura Martinez-Rubio
- Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, United Kingdom
| | - Sebastian Boltana
- Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, United Kingdom
| | - Douglas R. Tocher
- Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, United Kingdom
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Giammanco A, Cefalù AB, Noto D, Averna MR. The pathophysiology of intestinal lipoprotein production. Front Physiol 2015; 6:61. [PMID: 25852563 PMCID: PMC4367171 DOI: 10.3389/fphys.2015.00061] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 02/14/2015] [Indexed: 12/12/2022] Open
Abstract
Intestinal lipoprotein production is a multistep process, essential for the absorption of dietary fats and fat-soluble vitamins. Chylomicron assembly begins in the endoplasmic reticulum with the formation of primordial, phospholipids-rich particles that are then transported to the Golgi for secretion. Several classes of transporters play a role in the selective uptake and/or export of lipids through the villus enterocytes. Once secreted in the lymph stream, triglyceride-rich lipoproteins (TRLs) are metabolized by Lipoprotein lipase (LPL), which catalyzes the hydrolysis of triacylglycerols of very low density lipoproteins (VLDLs) and chylomicrons, thereby delivering free fatty acids to various tissues. Genetic mutations in the genes codifying for these proteins are responsible of different inherited disorders affecting chylomicron metabolism. This review focuses on the molecular pathways that modulate the uptake and the transport of lipoproteins of intestinal origin and it will highlight recent findings on TRLs assembly.
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Affiliation(s)
| | | | | | - Maurizio R. Averna
- Dipartimento Biomedico di Medicina Interna e Specialistica, Università degli Studi di PalermoPalermo, Italy
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14
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Functional dyspepsia patients have lower mucosal cholecystokinin concentrations in response to duodenal lipid. Eur J Gastroenterol Hepatol 2014; 26:205-12. [PMID: 24252886 DOI: 10.1097/meg.0000000000000001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
BACKGROUND Dyspeptic symptoms are frequently induced, or exacerbated, by fatty food ingestion. Excessive release of, and/or hypersensitivity to, cholecystokinin (CCK) may explain the exaggerated response to lipid in patients with functional dyspepsia (FD). Thus far, plasma CCK response has been evaluated. However, stimulation of CCK1 receptors on duodenal vagal afferents occurs in a paracrine manner, suggesting that mucosal CCK concentrations are relevant to quantify. Apolipoprotein A-IV stimulates mucosal CCK release. AIM To investigate the hypothesis that fat-induced release of CCK and apolipoprotein A-IV (apoA-IV) is enhanced in the duodenum of FD patients. PATIENTS AND METHODS Sixteen symptomatic FD patients and 10 healthy volunteers (HV) underwent duodenal perfusion with intralipid 20%, 2 kcal/min, for 60 min. Symptoms were scored and blood samples were collected every 15 min during lipid perfusion and 15 min after discontinuation when duodenal biopsies were taken. Plasma and mucosal concentrations of CCK and apoA-IV were quantified. RESULTS Abdominal discomfort (P=0.001), nausea (P=0.05), and fullness (P=0.005) in response to duodenal lipid increased significantly only in FD patients. Following lipid infusion, the mean mucosal CCK concentration was lower in FD patients compared with HV (P<0.0001). Fasting concentrations and plasma response of CCK were comparable in FD patients and HV. Plasma apoA-IV response appeared to differ between patients and HV, whereas mucosal apoA-IV concentrations were similar. CONCLUSION Our results suggest excessive local release of CCK in response to duodenal lipid in FD. This likely causes exaggerated stimulation of duodenal vagal afferents, explaining dyspeptic symptom generation. The mechanisms underlying elevated mucosal CCK release warrant further investigation.
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15
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VerHague MA, Cheng D, Weinberg RB, Shelness GS. Apolipoprotein A-IV Expression in Mouse Liver Enhances Triglyceride Secretion and Reduces Hepatic Lipid Content by Promoting Very Low Density Lipoprotein Particle Expansion. Arterioscler Thromb Vasc Biol 2013; 33:2501-8. [DOI: 10.1161/atvbaha.113.301948] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Melissa A. VerHague
- From the Department of Pathology (M.A.V., D.C., G.S.S.), Department of Internal Medicine (R.B.W.), and Department of Physiology & Pharmacology (R.B.W.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Dongmei Cheng
- From the Department of Pathology (M.A.V., D.C., G.S.S.), Department of Internal Medicine (R.B.W.), and Department of Physiology & Pharmacology (R.B.W.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Richard B. Weinberg
- From the Department of Pathology (M.A.V., D.C., G.S.S.), Department of Internal Medicine (R.B.W.), and Department of Physiology & Pharmacology (R.B.W.), Wake Forest School of Medicine, Winston-Salem, NC
| | - Gregory S. Shelness
- From the Department of Pathology (M.A.V., D.C., G.S.S.), Department of Internal Medicine (R.B.W.), and Department of Physiology & Pharmacology (R.B.W.), Wake Forest School of Medicine, Winston-Salem, NC
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16
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Kohan AB, Wang F, Li X, Vandersall AE, Huesman S, Xu M, Yang Q, Lou D, Tso P. Is apolipoprotein A-IV rate limiting in the intestinal transport and absorption of triglyceride? Am J Physiol Gastrointest Liver Physiol 2013; 304:G1128-35. [PMID: 23599044 PMCID: PMC3680714 DOI: 10.1152/ajpgi.00409.2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 04/16/2013] [Indexed: 01/31/2023]
Abstract
Apolipoprotein A-IV (apoA-IV) is synthesized by the intestine and secreted when dietary fat is absorbed and transported into lymph associated with chylomicrons. We have recently demonstrated that loss of apoA-IV increases chylomicron size and delays its clearance from the blood. There is still uncertainty, however, about the precise role of apoA-IV on the transport of dietary fat from the intestine into the lymph. ApoA-IV knockout (KO) mice do not have a gross defect in dietary lipid absorption, as measured by oral fat tolerance and fecal fat measurements. Here, using the in vivo lymph fistula mouse model, we show that the cumulative secretion of triglyceride (TG) into lymph in apoA-IV KO mice is very similar to that of wild-type (WT) mice. However, the apoA-IV KO mice do have subtle changes in TG accumulation in the intestinal mucosa during a 6-h continuous, but not bolus, infusion of lipid. There are no changes in the ratio of esterified to free fatty acids in the intestinal mucosa of the apoA-IV KO, however. When we extended these findings, by giving a higher dose of lipid (6 μmol/h) and for a longer infusion period (8 h), we found no effect of apoA-IV KO on intestinal TG absorption. This higher lipid infusion most certainly stresses the intestine, as we see a drastically lower absorption of TG (in both WT and KO mice); however, the loss of A-IV does not exacerbate this effect. This supports our hypothesis that apoA-IV is not required for TG absorption in the intestine. Our data suggest that the mechanisms by which the apoA-IV KO intestine responds to intestinal lipid may not be different from their WT counterparts. We conclude that apoA-IV is not required for normal lymphatic transport of TG.
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Affiliation(s)
- Alison B Kohan
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237, USA.
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17
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Postprandial changes in high density lipoproteins in rats subjected to gavage administration of virgin olive oil. PLoS One 2013; 8:e55231. [PMID: 23383120 PMCID: PMC3558467 DOI: 10.1371/journal.pone.0055231] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 12/28/2012] [Indexed: 01/30/2023] Open
Abstract
Background and Aims The present study was designed to verify the influence of acute fat loading on high density lipoprotein (HDL) composition, and the involvement of liver and different segments of small intestine in the changes observed. Methods and Results To address these issues, rats were administered a bolus of 5-ml of extra-virgin olive oil and sacrificed 4 and 8 hours after feeding. In these animals, lipoproteins were analyzed and gene expressions of apolipoprotein and HDL enzymes were assessed in duodenum, jejunum, ileum and liver. Using this experimental design, total plasma and HDL phospholipids increased at the 8-hour-time-point due to increased sphingomyelin content. An increase in apolipoprotein A4 was also observed mainly in lipid-poor HDL. Increased expression of intestinal Apoa1, Apoa4 and Sgms1 mRNA was accompanied by hepatic decreases in the first two genes in liver. Hepatic expression of Abcg1, Apoa1bp, Apoa2, Apoe, Ptlp, Pon1 and Scarb1 decreased significantly following fat gavage, while no changes were observed for Abca1, Lcat or Pla2g7. Significant associations were also noted for hepatic expression of apolipoproteins and Pon1. Manipulation of postprandial triglycerides using an inhibitor of microsomal transfer protein -CP-346086- or of lipoprotein lipase –tyloxapol- did not influence hepatic expression of Apoa1 or Apoa4 mRNA. Conclusion All these data indicate that dietary fat modifies the phospholipid composition of rat HDL, suggesting a mechanism of down-regulation of hepatic HDL when intestine is the main source of those particles and a coordinated regulation of hepatic components of these lipoproteins at the mRNA level, independently of plasma postprandial triglycerides.
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18
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van Boxel OS, ter Linde JJM, Oors J, Otto B, Feinle-Bisset C, Smout AJPM, Siersema PD. Duodenal lipid-induced symptom generation in gastroesophageal reflux disease: role of apolipoprotein A-IV and cholecystokinin. Neurogastroenterol Motil 2012; 24:350-e168. [PMID: 22300015 DOI: 10.1111/j.1365-2982.2012.01880.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Duodenal lipid intensifies the perception of esophageal acid perfusion. Recently, we showed that genes implicated in lipid absorption were upregulated in the duodenum of fasting gastro-esophageal reflux disease (GERD) patients. This suggests that chylomicron production and secretion may be enhanced and, consequently, the release of apolipoprotein A-IV (apoA-IV), a chylomicron-derived signaling protein. ApoA-IV may stimulate release of cholecystokinin (CCK), an activator of vagal afferents. This study evaluated putative involvement of abnormal apoA-IV and CCK responses to lipid in GERD. METHODS Ten GERD patients and 10 healthy volunteers (HV) underwent duodenal perfusion with Intralipid 20%, 2 kcal min(-1) , for 60 min. Symptoms were scored, blood samples collected every 15 min during lipid perfusion and 15 min after discontinuation when duodenal biopsies were taken. Plasma and mucosal concentrations of apoA-IV and CCK and transcript levels of 21 genes implicated in lipid absorption, differentially expressed under fasting conditions, were quantified. KEY RESULTS Heartburn (P = 0.003), abdominal discomfort (P = 0.037) and nausea (P = 0.008) only increased significantly during lipid infusion in GERD patients. Following lipid infusion mean mucosal apoA-IV concentration was lower in GERD patients compared with HV (P = 0.023), whereas plasma concentration tended to be elevated (P = 0.068). Mean mucosal CCK concentration was also lower in GERD patients (P = 0.009). Two genes, HIBADH and JTB, were upregulated in GERD patients (P = 0.008 and P = 0.038, respectively). CONCLUSIONS & INFERENCES Our results suggest excessive duodenal lipid-induced release of apoA-IV and CCK in GERD. We postulate that the resulting heightened activation of duodenal vagal afferents may underlie central sensitization, thereby increasing the perception of reflux events.
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Affiliation(s)
- O S van Boxel
- Department of Gastroenterology and Hepatology, University Medical Centre, Utrecht, the Netherlands.
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19
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Kohan AB, Wang F, Li X, Bradshaw S, Yang Q, Caldwell JL, Bullock TM, Tso P. Apolipoprotein A-IV regulates chylomicron metabolism-mechanism and function. Am J Physiol Gastrointest Liver Physiol 2012; 302:G628-36. [PMID: 22207575 PMCID: PMC3311309 DOI: 10.1152/ajpgi.00225.2011] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Dietary fat is an important mediator of atherosclerosis and obesity. Despite its importance in mediating metabolic disease, there is still much unknown about dietary fat absorption in the intestine and especially the detailed biological roles of intestinal apolipoproteins involved in that process. We were specifically interested in determining the physiological role of the intestinal apolipoprotein A-IV (A-IV) using A-IV knockout (KO) mice. A-IV is stimulated by fat absorption in the intestine and is secreted on nascent chylomicrons into intestinal lymph. We found that A-IV KO mice had reduced plasma triglyceride (TG) and cholesterol levels and that this hypolipidemia persisted on a high-fat diet. A-IV KO did not cause abnormal intestinal lipid absorption, food intake, or adiposity. Additionally, A-IV KO did not cause abnormal liver TG and cholesterol metabolism, as assessed by measuring hepatic lipid content, lipogenic and cholesterol synthetic gene expression, and in vivo VLDL secretion. Instead, A-IV KO resulted in the secretion of larger chylomicrons from the intestine into the lymph, and those chylomicrons were cleared from the plasma more slowly than wild-type chylomicrons. These data suggest that A-IV has a previously unknown role in mediating the metabolism of chylomicrons, and therefore may be important in regulating plasma lipid metabolism.
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Affiliation(s)
- Alison B. Kohan
- 1Department of Pathology and Laboratory Medicine, University of Cincinnati; and
| | - Fei Wang
- 1Department of Pathology and Laboratory Medicine, University of Cincinnati; and
| | - Xiaoming Li
- 1Department of Pathology and Laboratory Medicine, University of Cincinnati; and
| | - Suzanne Bradshaw
- 2Department of Biology, University of Cincinnati, Blue Ash College, Cincinnati, Ohio
| | - Qing Yang
- 1Department of Pathology and Laboratory Medicine, University of Cincinnati; and
| | - Jody L. Caldwell
- 1Department of Pathology and Laboratory Medicine, University of Cincinnati; and
| | - Tera M. Bullock
- 1Department of Pathology and Laboratory Medicine, University of Cincinnati; and
| | - Patrick Tso
- 1Department of Pathology and Laboratory Medicine, University of Cincinnati; and
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20
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Weinberg RB, Gallagher JW, Fabritius MA, Shelness GS. ApoA-IV modulates the secretory trafficking of apoB and the size of triglyceride-rich lipoproteins. J Lipid Res 2012; 53:736-43. [PMID: 22257482 DOI: 10.1194/jlr.m019992] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Although the evidence linking apoA-IV expression and triglyceride (TG)-rich lipoprotein assembly and secretion is compelling, the intracellular mechanisms by which apoA-IV could modulate these processes remain poorly understood. We therefore examined the functional impact of apoA-IV expression on endogenous apoB, TG, and VLDL secretion in stably transfected McA-RH7777 rat hepatoma cells. Expression of apoA-IV modified with the endoplasmic reticulum (ER) retention signal KDEL (apoA-IV-KDEL) dramatically decreased both the rate and efficiency of endogenous apoB secretion, suggesting a presecretory interaction between apoA-IV-KDEL and apoB or apoB-containing lipoproteins. Expression of native apoA-IV using either a constitutive or tetracycline-inducible promoter delayed the initial rate of apoB secretion and reduced the final secretion efficiency by ∼40%. However, whereas apoA-IV-KDEL reduced TG secretion by 75%, expression of native apoA-IV caused a 20-35% increase in TG secretion, accompanied by a ∼55% increase in VLDL-associated apoB, an increase in the TG:phospholipid ratio of secreted d < 1.006 lipoproteins, and a 10.1 nm increase in peak VLDL(1) particle diameter. Native apoA-IV expression had a negligible impact on expression of the MTP gene. These data suggest that by interacting with apoB in the secretory pathway, apoA-IV alters the trafficking kinetics of apoB-containing TG-rich lipoproteins through cellular lipidation compartments, which in turn, enhances particle expansion and increases TG secretion.
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Affiliation(s)
- Richard B Weinberg
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
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21
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Transcriptomic analyses of intestinal gene expression of juvenile Atlantic cod (Gadus morhua) fed diets with Camelina oil as replacement for fish oil. Comp Biochem Physiol B Biochem Mol Biol 2011; 161:283-93. [PMID: 22198123 DOI: 10.1016/j.cbpb.2011.12.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 12/09/2011] [Accepted: 12/10/2011] [Indexed: 11/23/2022]
Abstract
For aquaculture of marine species to continue to expand, dietary fish oil (FO) must be replaced with more sustainable vegetable oil (VO) alternatives. Most VO are rich in n-6 polyunsaturated fatty acids (PUFA) and few are rich in n-3 PUFA but Camelina oil (CO) is unique in that, besides high 18:3n-3 and n-3/n-6 PUFA ratio, it also contains substantial long-chain monoenes, commonly found in FO. Cod (initial mass ~1.4 g) were fed for 12 weeks diets in which FO was replaced with CO. Growth performance, feed efficiency and biometric indices were not affected but lipid levels in liver and intestine tended to increase and those of flesh, decrease, with increasing dietary CO although only significantly for intestine. Reflecting diet, tissue n-3 long-chain PUFA levels decreased whereas 18:3n-3 and 18:2n-6 increased with inclusion of dietary CO. Dietary replacement of FO by CO did not induce major metabolic changes in intestine, but affected genes with potential to alter cellular proliferation and death as well as change structural properties of intestinal muscle. Although the biological effects of these changes are unclear, given the important role of intestine in nutrient absorption and health, further attention should be given to this organ in future.
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22
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Simon T, Cook VR, Rao A, Weinberg RB. Impact of murine intestinal apolipoprotein A-IV expression on regional lipid absorption, gene expression, and growth. J Lipid Res 2011; 52:1984-94. [PMID: 21840868 DOI: 10.1194/jlr.m017418] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Apolipoprotein A-IV (apoA-IV) is synthesized by intestinal enterocytes during lipid absorption and secreted into lymph on the surface of nascent chylomicrons. A compelling body of evidence supports a central role of apoA-IV in facilitating intestinal lipid absorption and in regulating satiety, yet a longstanding conundrum is that no abnormalities in fat absorption, feeding behavior, or weight gain were observed in chow-fed apoA-IV knockout (A4KO) mice. Herein we reevaluated the impact of apoA-IV expression in C57BL6 and A4KO mice fed a high-fat diet. Fat balance and lymph cannulation studies found no effect of intestinal apoA-IV gene expression on the efficiency of fatty acid absorption, but gut sac transport studies revealed that apoA-IV differentially modulates lipid transport and the number and size of secreted triglyceride-rich lipoproteins in different anatomic regions of the small bowel. ApoA-IV gene deletion increased expression of other genes involved in chylomicron assembly, impaired the ability of A4KO mice to gain weight and increase adipose tissue mass, and increased the distal gut hormone response to a high-fat diet. Together these findings suggest that apoA-IV may play a unique role in integrating feeding behavior, intestinal lipid absorption, and energy storage.
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Affiliation(s)
- Trang Simon
- Departments of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
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23
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Yao Y, Lu S, Huang Y, Beeman-Black CC, Lu R, Pan X, Hussain MM, Black DD. Regulation of microsomal triglyceride transfer protein by apolipoprotein A-IV in newborn swine intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2011; 300:G357-63. [PMID: 21127258 PMCID: PMC3043654 DOI: 10.1152/ajpgi.00353.2010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Apolipoprotein (apo) A-IV overexpression enhances chylomicron (CM) assembly and secretion in newborn swine intestinal epithelial cells by producing larger particles (Lu S, Yao Y, Cheng X, Mitchell S, Leng S, Meng S, Gallagher JW, Shelness GS, Morris GS, Mahan J, Frase S, Mansbach CM, Weinberg RB, Black DD. J Biol Chem 281: 3473-3483, 2006). To determine the impact of apo A-IV on microsomal triglyceride transfer protein (MTTP), IPEC-1 cell lines containing a tetracycline-regulatable expression system were used to overexpress native swine apo A-IV and "piglike" human apo A-IV, a mutant human apo A-IV with deletion of the EQQQ-rich COOH-terminus, previously shown to upregulate basolateral triglyceride (TG) secretion 5-fold and 25-fold, respectively. Cells were incubated 24 h with and without doxycycline and oleic acid (OA, 0.8 mM). Overexpression of the native swine apo A-IV and piglike human apo A-IV increased MTTP lipid transfer activity by 39.7% (P = 0.006) and 53.6% (P = 0.0001), respectively, compared with controls. Changes in mRNA and protein levels generally paralleled changes in activity. Interestingly, native swine apo A-IV overexpression also increased MTTP large subunit mRNA, protein levels, and lipid transfer activity in the absence of OA, suggesting a mechanism not mediated by lipid absorption. Overexpression of piglike human apo A-IV significantly increased partitioning of radiolabeled OA from endoplasmic reticulum (ER) membrane to lumen, suggesting increased net transfer of membrane TG to luminal particles. These results suggest that the increased packaging of TG into nascent CMs in the ER lumen, induced by apo A-IV, is associated with upregulation of MTTP activity at the pretranslational level. Thus MTTP is regulated by apo A-IV in a manner to promote increased packaging of TG into the CM core, which may be important in neonatal fat absorption.
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Affiliation(s)
- Ying Yao
- 1Children's Foundation Research Center at Le Bonheur Children's Medical Center, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Song Lu
- 1Children's Foundation Research Center at Le Bonheur Children's Medical Center, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Yue Huang
- 1Children's Foundation Research Center at Le Bonheur Children's Medical Center, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Casey C. Beeman-Black
- 1Children's Foundation Research Center at Le Bonheur Children's Medical Center, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Rena Lu
- 1Children's Foundation Research Center at Le Bonheur Children's Medical Center, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Xiaoyue Pan
- 2Departments of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York
| | - M. Mahmood Hussain
- 2Departments of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, New York
| | - Dennis D. Black
- 1Children's Foundation Research Center at Le Bonheur Children's Medical Center, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee; and
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Weinberg RB, Cook VR. Distinctive structure and interfacial activity of the human apolipoprotein A-IV 347S isoprotein. J Lipid Res 2010; 51:2664-71. [PMID: 20554794 PMCID: PMC2918448 DOI: 10.1194/jlr.m007021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 06/16/2010] [Indexed: 11/20/2022] Open
Abstract
The T347S polymorphism in the human apolipoprotein (apo) A-IV gene is present at high frequencies among all the world's populations. Carriers of a 347S allele exhibit faster clearance of triglyceride-rich lipoproteins, greater adiposity, and increased risk for developing atherosclerosis, which suggests that this conservative amino acid substitution alters the structure of apo A-IV. Herein we have used spectroscopic and surface chemistry techniques to examine the structure, stability, and interfacial properties of the apo A-IV 347S isoprotein. Circular dichroism spectroscopy revealed that the 347S isoprotein has similar alpha-helical structure but lower thermodynamic stability than the 347T isoprotein. Fluorescence spectroscopy found that the 347S isoprotein exhibits an enhanced tyrosine emission and reduced tyrosine-->tryptophan energy transfer, and second derivative UV absorption spectra noted increased tyrosine exposure, suggesting that the 347S isoprotein adopts a looser tertiary conformation. Surface chemistry studies found that although the 347S isoprotein bound rapidly to the lipid interface, it has a lower interfacial exclusion pressure and lower elastic modulus than the 347T isoprotein. Together, these observations establish that the T347S substitution alters the conformation of apo A-IV and lowers its interfacial activity-changes that could account for the effect of this polymorphism on postprandial lipid metabolism.
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Affiliation(s)
- Richard B Weinberg
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
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25
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Tubb MR, Smith LE, Davidson WS. Purification of recombinant apolipoproteins A-I and A-IV and efficient affinity tag cleavage by tobacco etch virus protease. J Lipid Res 2009; 50:1497-504. [PMID: 19318686 DOI: 10.1194/jlr.d900003-jlr200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The expression of recombinant apolipoproteins provides experimental avenues that are not possible with plasma purified protein. The ability to specifically mutate residues or delete entire regions has proven to be a valuable tool for understanding the structure and function of apolipoproteins. A common feature of many recombinant systems is an affinity tag that allows for straightforward and high-yield purification of the target protein. A specific protease can then cleave the tag and yield the native recombinant protein. However, the application of this strategy to apolipoproteins has proven somewhat problematic because of the tendency for these highly flexible proteins to be nonspecifically cleaved at undesired sites within the native protein. Although systems have been developed using a variety of proteases, many suffer from low yield and, especially, the high cost of the enzyme.We developed a method that utilizes the tobacco etch virus protease to cleave a histidine-tag from apolipoproteins A-I and A-IV expressed in Escherichia coli. This protease can be easily and inexpensively expressed within most laboratories. We found that the protease efficiently cleaved the affinity tags from both apolipoproteins without nonspecific cleavage. All structural and functional measurements showed that the proteins were equivalent to native or previously characterized protein preparations. In addition to cost-effectiveness, advantages of the tobacco etch virus protease include a short cleavage time, low reaction temperature, and easy removal using the protease's own histidine-tag.
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Affiliation(s)
- Matthew R Tubb
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237-0507, USA
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26
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Abstract
OBJECTIVE The ileal brake is a feedback mechanism activated by nutrients, especially fat, with marked effects on satiety. The effects of low doses of ileal fat on satiety are largely unknown. We therefore studied the effect of ileal vs oral delivery of low doses of fat on satiety and gut peptide secretion. DESIGN Randomized, single-blind crossover design. SUBJECTS Sixteen healthy, normal-weight volunteers (6 male; mean age 26 years, mean body mass index 22.4). INTERVENTION Participants were intubated with a 290-cm-long nasoileal tube and consumed, on 3 consecutive days, either a liquid breakfast with 3 g fat followed by an ileal placebo infusion at t=105-150 min (treatment C) or a fat-free liquid breakfast followed by an ileal infusion of either an emulsion of 3 g (treatment 13 g) or 9 g (treatment 19 g) fat (safflower oil). MEASUREMENTS Satiety parameters by visual analog scales and plasma concentrations of CCK and PYY. RESULTS C significantly increased satiety and CCK secretion compared with the fat-free breakfast. Ileal fat perfusion of both 3 and 9 g 13 g and 19 g) significantly increased satiety during and after fat perfusion, without differences in satiety between 13 g and 19 g. During ileal fat infusion, CCK increased dose dependently, whereas PYY concentrations increased significantly only after 9 g of fat. Secretion of CCK but not of PYY correlated to satiety levels. CONCLUSION Postprandial satiety following a liquid breakfast can be effectively and significantly increased by small amounts (as little as 3 g) of fat perfused into the ileum. Ileal fat dose-dependently increased CCK but not PYY secretion. The satiating effect of ileal fat may be partly mediated by CCK.
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27
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Tubb MR, Silva RAGD, Fang J, Tso P, Davidson WS. A three-dimensional homology model of lipid-free apolipoprotein A-IV using cross-linking and mass spectrometry. J Biol Chem 2008; 283:17314-23. [PMID: 18430727 PMCID: PMC2427326 DOI: 10.1074/jbc.m800036200] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Revised: 04/10/2008] [Indexed: 11/06/2022] Open
Abstract
Human apolipoprotein A-IV (apoA-IV) is a 46-kDa exchangeable plasma protein with many proposed functions. It is involved in chylomicron assembly and secretion, protection from atherosclerosis through a variety of mechanisms, and inhibition of food intake. There is little structural basis for these proposed functions due to the lack of a solved three-dimensional structure of the protein by x-ray crystallography or NMR. Based on previous studies, we hypothesized that lipid-free apoA-IV exists in a helical bundle, like other apolipoprotein family members and that regions near the N and C termini may interact. Utilizing a homobifunctional lysine cross-linking agent, we identified 21 intramolecular cross-links by mass spectrometry. These cross-links were used to constrain the building of a sequence threaded homology model using the I-TASSER server. Our results indicate that lipid-free apoA-IV does indeed exist as a complex helical bundle with the N and C termini in close proximity. This first structural model of lipid-free apoA-IV should prove useful for designing studies aimed at understanding how apoA-IV interacts with lipids and possibly with unknown protein partners.
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Affiliation(s)
- Matthew R Tubb
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237, USA
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28
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Tubb MR, Silva RAGD, Pearson KJ, Tso P, Liu M, Davidson WS. Modulation of apolipoprotein A-IV lipid binding by an interaction between the N and C termini. J Biol Chem 2007; 282:28385-28394. [PMID: 17686771 DOI: 10.1074/jbc.m704070200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein A-IV (apoA-IV) is a 376-amino acid exchangeable apolipoprotein made in the small intestine of humans. Although it has many proposed roles in vascular disease, satiety, and chylomicron metabolism, there is no known structural basis for these functions. The ability to associate with lipids may be a key step in apoA-IV functionality. We recently identified a single amino acid, Phe(334), which seems to inhibit the lipid binding capability of apoA-IV. We also found that an intact N terminus was necessary for increased lipid binding of Phe(334) mutants. Here, we identify Trp(12) and Phe(15) as the N-terminal amino acids required for the fast lipid binding seen with the F334A mutant. Furthermore, we found that individual disruption of putative amphipathic alpha-helices 3-11 had little effect on lipid binding, suggesting that the N terminus of apoA-IV may be the operational site for initial lipid binding. We also provide three independent pieces of experimental evidence supporting a direct intramolecular interaction between sequences near amino acids 12/15 and 334. This interaction could represent a unique "switch" mechanism by which apoA-IV changes lipid avidity in vivo.
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Affiliation(s)
- Matthew R Tubb
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237
| | - R A Gangani D Silva
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237
| | - Kevin J Pearson
- Laboratory of Experimental Gerontology, NIA, National Institutes of Health, Baltimore, Maryland 21224
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237
| | - Min Liu
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237
| | - W Sean Davidson
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237.
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29
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Leng S, Lu S, Yao Y, Kan Z, Morris GS, Stair BR, Cherny MA, Black DD. Hepatocyte nuclear factor-4 mediates apolipoprotein A-IV transcriptional regulation by fatty acid in newborn swine enterocytes. Am J Physiol Gastrointest Liver Physiol 2007; 293:G475-83. [PMID: 17556588 DOI: 10.1152/ajpgi.00072.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Hepatocyte nuclear factor-4alpha (HNF-4alpha) regulates transcription of several genes involved in lipid metabolism, including that of apolipoprotein (apo) A-IV, which is tightly regulated by lipid absorption and enhances enterocyte chylomicron secretion. Studies were performed to define the role of HNF-4alpha in the regulation of apo A-IV gene transcription by dietary fatty acid in neonatal swine small intestine. HNF-4alpha mRNA was expressed in liver > intestine > kidney in suckling, weanling, and weaned pigs. Jejunal HNF-4alpha mRNA and protein and apo A-IV and swine microsomal triglyceride transfer protein (MTP) large subunit mRNA expression were induced in parallel in 2-day-old swine by a 24-h high-fat intraduodenal infusion. In IPEC-1 cells, incubation with oleic acid (OA) resulted in coordinate induction of both HNF-4alpha, apo A-IV, and MTP mRNA, similar to that observed in vivo. When HNF-4alpha expression was driven by doxycycline by using the TET-On system in the absence of OA to observe the effect of HNF-4alpha directly on apo A-IV and MTP mRNA levels in the absence of other factors that might be concomitantly induced by fatty acid absorption, apo A-IV and MTP expression were increased. In luciferase reporter gene assays in IPEC-1 cells using apo A-IV/C-III intergenic region constructs, TET-On-regulated HNF-4alpha expression without OA increased luciferase activity, and incubation with OA did not further increase activity. These data suggest that acute induction of the apo A-IV and MTP genes by dietary lipid in newborn intestine occurs, at least in part, via ligand-independent transactivation by HNF-4alpha that is itself induced by a lipid-mediated mechanism.
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Affiliation(s)
- Shuangying Leng
- Children's Foundation Research Center of Memphis, Le Bonheur Children's Medical Center, Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN 38103, USA
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30
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Spaulding HL, Saijo F, Turnage RH, Alexander JS, Aw TY, Kalogeris TJ. Apolipoprotein A-IV attenuates oxidant-induced apoptosis in mitotic competent, undifferentiated cells by modulating intracellular glutathione redox balance. Am J Physiol Cell Physiol 2006; 290:C95-C103. [PMID: 16120654 DOI: 10.1152/ajpcell.00388.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Oxidant-mediated modulation of the intracellular redox state affects the apoptotic cascade by altering the balance between cellular signals for survival and suicide. Apolipoprotein A-IV (Apo A-IV) is known to possess antioxidant-like activity. In the present study, we tested 1) whether Apo A-IV could influence redox-dependent apoptosis and, if so, 2) whether such an effect could be mediated by modulation of intracellular redox balance. Mitotic competent, undifferentiated PC-12 cells were incubated with either tert-butyl hydroperoxide (TBH) or diamide with or without preincubation with human Apo A-IV. Apo A-IV significantly decreased apoptosis produced by both TBH and diamide, and washout of A-IV before incubation with TBH and diamide did not eliminate its protective effect. Apo A-I had no such protective effect. The Apo A-IV effect was not blocked by d,l-buthionine-[ S, R]-sulfoximine, but it was reversed by both dehydroisoandrosterone and transfection with an antisense oligodeoxynucleotide to glucose-6-phosphate dehydrogenase (G6PD). Apo A-IV abolished the transient, oxidant-induced rise in glutathione disulfide (GSSG) and cellular redox imbalance previously shown to initiate the apoptotic cascade. Apo A-IV had no effect on GSSG reductase activity, but it stimulated G6PD activity 10-fold. These results suggest a novel role for Apo A-IV in the regulation of intracellular glutathione redox balance and the modulation of redox-dependent apoptosis via stimulation of G6PD activity.
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Affiliation(s)
- Heather L Spaulding
- Dept. of Surgery, Louisiana State Univ. Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130, USA
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31
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Lu S, Yao Y, Cheng X, Mitchell S, Leng S, Meng S, Gallagher JW, Shelness GS, Morris GS, Mahan J, Frase S, Mansbach CM, Weinberg RB, Black DD. Overexpression of apolipoprotein A-IV enhances lipid secretion in IPEC-1 cells by increasing chylomicron size. J Biol Chem 2005; 281:3473-83. [PMID: 16338933 DOI: 10.1074/jbc.m502501200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Intestinal apolipoprotein A-IV expression is highly regulated by dietary lipid in newborn swine, suggesting a role in lipid absorption. Constitutive overexpression of apoA-IV in newborn swine enterocytes enhances basolateral secretion of triacylglycerol (TG) in TG-rich lipoproteins 4.9-fold (Lu, S., Yao, Y., Meng, S., Cheng, X., and Black, D. D. (2002) J. Biol. Chem. 277, 31929-31937). To investigate the mechanism of this enhancement, IPEC-1 cells were transfected with a tetracycline-regulatable expression system (Tet-On). In cells incubated with oleic acid, a dose response relationship was observed between medium doxycycline concentration and basolateral apoA-IV and TG secretion. Similarly regulated expression of apoA-I did not enhance lipid secretion. The mean diameter of TG-rich lipoproteins secreted from doxycycline-treated cells was larger than from untreated cells (87.0 nm versus 53.4 nm). Basolateral apoB secretion decreased. Using the same expression system, full-length human apoA-IV (376 amino acids); a "pig-like" human apoA-IV, lacking the C-terminal EQQQ repeats (361 amino acids); and a "chicken-like" apoA-IV, further truncated to 343 amino acids, were expressed in IPEC-1 cells. With increasing protein secretion, cells expressing the full-length human apoA-IV displayed a 2-fold increase in TG secretion; in sharp contrast, cells expressing the pig-like human apoA-IV displayed a 25-fold increase in TG secretion and a 27-fold increase in lipoprotein diameter. When human apoA-IV was further truncated to yield a chicken-like protein, TG secretion was inhibited. We conclude that overexpression of swine apoA-IV enhances basolateral TG secretion in a dose-dependent manner by increasing the size of secreted lipoproteins. These data suggest that the region in the human apoA-IV protein from residues 344 to 354 is critical to its ability to enhance lipid secretion, perhaps by enabling the packaging of additional core TG into chylomicron particles. The EQQQ-rich region may play an inhibitory or modulatory role in chylomicron packaging in humans.
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MESH Headings
- Amino Acid Sequence
- Animals
- Animals, Newborn
- Apolipoproteins/chemistry
- Apolipoproteins A/biosynthesis
- Apolipoproteins A/physiology
- Blotting, Western
- Cell Line
- Chickens
- Chylomicrons/chemistry
- Cloning, Molecular
- DNA, Complementary/metabolism
- Dose-Response Relationship, Drug
- Doxycycline/metabolism
- Doxycycline/pharmacology
- Electrophoresis, Polyacrylamide Gel
- Humans
- Immunoprecipitation
- Intestinal Mucosa/metabolism
- Intestines/cytology
- Lipid Metabolism
- Lipids/chemistry
- Lipoproteins/metabolism
- Microscopy, Electron
- Microscopy, Electron, Transmission
- Molecular Sequence Data
- Mutation
- Oleic Acid/chemistry
- Oleic Acid/metabolism
- Protein Structure, Tertiary
- RNA/metabolism
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Swine
- Tetracycline/pharmacology
- Transcriptional Activation
- Triglycerides/metabolism
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Affiliation(s)
- Song Lu
- Children's Foundation Research Center at Le Bonheur Children's Medical Center and Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee 38103, USA
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32
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Pearson K, Tubb MR, Tanaka M, Zhang XQ, Tso P, Weinberg RB, Davidson WS. Specific Sequences in the N and C Termini of Apolipoprotein A-IV Modulate Its Conformation and Lipid Association. J Biol Chem 2005; 280:38576-82. [PMID: 16159879 DOI: 10.1074/jbc.m506802200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein (apoA-IV) is a 376-residue exchangeable apolipoprotein that may play a number of important roles in lipid metabolism, including chylomicron assembly, reverse cholesterol transport, and appetite regulation. In vivo, apoA-IV exists in both lipid-poor and lipid-associated forms, and the balance between these states may determine its function. We examined the structural elements that modulate apoA-IV lipid binding by producing a series of deletion mutants and determining their ability to interact with phospholipid liposomes. We found that the deletion of residues 333-343 strongly increased the lipid association rate versus native apoA-IV. Additional mutagenesis revealed that two phenylalanine residues at positions 334 and 335 mediated this lipid binding inhibitory effect. We also observed that residues 11-20 in the N terminus were required for the enhanced lipid affinity induced by deletion of the C-terminal sequence. We propose a structural model in which these sequences can modulate the conformation and lipid affinity of apoA-IV.
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Affiliation(s)
- Kevin Pearson
- Department of Pathology and Laboratory Medicine, The University of Cincinnati, Cincinnati, Ohio 45237-0507, USA
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33
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Gallagher JW, Weinberg RB, Shelness GS. apoA-IV tagged with the ER retention signal KDEL perturbs the intracellular trafficking and secretion of apoB. J Lipid Res 2004; 45:1826-34. [PMID: 15258202 DOI: 10.1194/jlr.m400188-jlr200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To examine the role of apolipoprotein A-IV (apoA-IV) in the intracellular trafficking and secretion of apoB, COS cells were cotransfected with microsomal triglyceride transfer protein (MTP), apoB-41 (amino terminal 41% of apoB), and either native apoA-IV or apoA-IV modified with the carboxy-terminal endoplasmic reticulum (ER) retention signal, KDEL (apoA-IV-KDEL). As expected, apoA-IV-KDEL was inefficiently secreted relative to native apoA-IV. Coexpression of apoB-41 with apoA-IV-KDEL reduced the secretion of apoB-41 by approximately 80%. The apoA-IV-KDEL effect was specific, as neither KDEL-modified forms of human serum albumin or apoA-I affected apoB-41 secretion. Similar results were observed in McA-RH7777 rat hepatoma cells, which express endogenous MTP. The full inhibitory effect of apoA-IV-KDEL on apoB secretion was observed only for forms of apoB containing a minimum of the amino-terminal 25% of the protein (apoB-25). However, apoA-IV-KDEL inhibited the secretion of both lipid-associated and lipid-poor forms of apoB-25. Dual-label immunofluorescence microscopy of cells transfected with native apoA-IV and apoB-25 revealed that both apolipoproteins were localized to the ER and Golgi, as expected. However, when apoA-IV-KDEL was cotransfected with apoB-25, both proteins localized primarily to the ER. These data suggest that apoA-IV may physically interact with apoB in the secretory pathway, perhaps reflecting a role in modulating the process of triglyceride-rich lipoprotein assembly and secretion.
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Affiliation(s)
- James W Gallagher
- Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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34
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Kratz M, Wahrburg U, von Eckardstein A, Ezeh B, Assmann G, Kronenberg F. Dietary mono- and polyunsaturated fatty acids similarly increase plasma apolipoprotein A-IV concentrations in healthy men and women. J Nutr 2003; 133:1821-5. [PMID: 12771323 DOI: 10.1093/jn/133.6.1821] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We investigated the effect of dietary fatty acid composition on plasma apolipoprotein (apo) A-IV concentrations. Plasma apo A-IV concentrations were measured by ELISA in plasma of 48 healthy men and women in a controlled dietary study. First, all participants consumed a 2-wk baseline diet rich in saturated fatty acids (SFA). Then, they were randomly assigned to one of three dietary treatments, which contained refined olive oil [rich in monounsaturated fatty acids (MUFA), n = 17], rapeseed oil [rich in MUFA and alpha-linolenic acid [18:3(n-3)], n = 13], or sunflower oil [rich in (n-6) PUFA, n = 18] as the principal source of fat for 4 wk. The plasma concentrations of apo A-IV increased when subjects consumed the diets rich in unsaturated fatty acids, by 16% or 13.0 mg/L [F((2,76)) = 12.874, P < 0.001 by repeated-measures ANOVA]. The increase was not affected by diet group affiliation, gender or apo A-IV genotype. In conclusion, diets rich in unsaturated fatty acids, independent of the degree of unsaturation, gender and apo A-IV genotype, increase plasma apo A-IV concentrations compared with a baseline diet rich in SFA in healthy men and women.
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Affiliation(s)
- Mario Kratz
- Institute of Arteriosclerosis Research at the University of Münster, 48149 Münster, Germany.
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35
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Lu S, Yao Y, Meng S, Cheng X, Black DD. Overexpression of apolipoprotein A-IV enhances lipid transport in newborn swine intestinal epithelial cells. J Biol Chem 2002; 277:31929-37. [PMID: 12070145 DOI: 10.1074/jbc.m201418200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein A-IV (apoA-IV) has myriad functions, including roles as a post-prandial satiety factor and lipid antioxidant. ApoA-IV is expressed in mammalian small intestine and is up-regulated in response to lipid absorption. In newborn swine jejunum, a high fat diet acutely induces a 7-fold increase in apoA-IV expression. To determine whether apoA-IV plays a role in the transport of absorbed lipid, swine apoA-IV was overexpressed in a newborn swine enterocyte cell line, IPEC-1, followed by analysis of the expression of genes related to lipoprotein assembly and lipid transport, as well as quantitation of lipid synthesis and secretion. A full-length swine apoA-IV cDNA was cloned, sequenced, and inserted into a Vp and Rep gene-deficient adeno-associated viral vector, containing the cytomegalovirus immediate early promoter/enhancer and neomycin resistance gene, and was used to transfect IPEC-1 cells. Control cells were transfected with the same vector minus the apoA-IV insert. Using neomycin selection, apoA-IV-overexpressing (+AIV) and control (-AIV) clones were isolated for further study. Both undifferentiated (-D) and differentiated (+D) +AIV cells expressed 40- to 50-fold higher levels of apoA-IV mRNA and both intracellular and secreted apoA-IV protein compared with -AIV cells. Expression of other genes was not affected by apoA-IV overexpression in a manner that would contribute to enhanced lipid secretion. +D +AIV cells secreted 4.9-fold more labeled triacylglycerol (TG), 4.6-fold more labeled cholesteryl ester (CE), and 2-fold more labeled phospholipid (PL) as lipoproteins, mostly in the chylomicron/very low density lipoprotein (VLDL) density range. ApoA-IV overexpression in IPEC-1 cells enhances basolateral TG, CE, and PL secretion in chylomicron/VLDL particles. This enhancement is not associated with up-regulation of other genes involved in lipid transport. ApoA-IV may play a role in facilitating enterocyte lipid transport, particularly in the neonate receiving a diet of high fat breast milk.
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Affiliation(s)
- Song Lu
- Children's Foundation Research Center at Le Bonheur Children's Medical Center, University of Tennessee Health Science Center, Memphis, Tennessee 38103, USA
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36
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Weinberg RB, Anderson RA, Cook VR, Emmanuel F, Denèfle P, Tall AR, Steinmetz A. Interfacial exclusion pressure determines the ability of apolipoprotein A-IV truncation mutants to activate cholesterol ester transfer protein. J Biol Chem 2002; 277:21549-53. [PMID: 11940599 DOI: 10.1074/jbc.m202197200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We used a panel of recombinant human apolipoprotein (apo) A-IV truncation mutants, in which pairs of 22-mer alpha-helices were sequentially deleted along the primary sequence, to examine the impact of protein structure and interfacial activity on the ability of apoA-IV to activate cholesterol ester transfer protein. Circular dichroism and fluorescence spectroscopy revealed that the secondary structure, conformation, and molecular stability of recombinant human apoA-IV were identical to the native protein. However, deletion of any of the alpha-helical domains in apoA-IV disrupted its tertiary structure and impaired its molecular stability. Surprisingly, determination of the water/phospholipid interfacial exclusion pressure of the apoA-IV truncation mutants revealed that, for most, deletion of amphipathic alpha-helical domains increased their affinity for phospholipid monolayers. All of the truncation mutants activated the transfer of fluorescent-labeled cholesterol esters between high and low density lipoproteins at a rate higher than native apoA-IV. There was a strong positive correlation (r = 0.790, p = 0.002) between the rate constant for cholesterol ester transfer and interfacial exclusion pressure. We conclude that molecular interfacial exclusion pressure, rather than specific helical domains, determines the degree to which apoA-IV, and likely other apolipoproteins, facilitate cholesterol ester transfer protein-mediated lipid exchange.
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Affiliation(s)
- Richard B Weinberg
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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37
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Abstract
Apolipoprotein A-IV is a 46kDa glycoprotein that is synthesized by intestinal enterocytes and is incorporated into the surface of nascent chylomicrons. Considerable evidence suggests that apolipoprotein A-IV plays a role in intestinal lipid absorption and chylomicron assembly. We have proposed that polymorphisms that alter the interfacial behavior of apolipoprotein A-IV may modulate the physical properties and metabolic fate of plasma chylomicrons. Of the reported genetic polymorphisms of apolipoprotein A-IV, two, Q360H and T347S, are known to occur at high frequencies among the world populations. Biophysical studies have established that the Q360H isoprotein displays higher lipid affinity; conversely the T347S isoprotein is predicted to be less lipid avid. Recent studies have shown that the Q360H polymorphism is associated with increased postprandial hypertriglyceridemia, a reduced low-density lipoprotein response to dietary cholesterol in the setting of a moderate fat intake, an increased high-density lipoprotein response to changes in total dietary fat content, and lower body mass and adiposity; the T347S polymorphism appears to confer the opposite effects. Studies on the diet-gene interactions of other apolipoprotein A-IV alleles are needed, as are studies on the interactions between apolipoprotein A-IV alleles and other apolipoprotein polymorphisms.
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Affiliation(s)
- Richard B Weinberg
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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38
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Gregoire FM, Zhang Q, Smith SJ, Tong C, Ross D, Lopez H, West DB. Diet-induced obesity and hepatic gene expression alterations in C57BL/6J and ICAM-1-deficient mice. Am J Physiol Endocrinol Metab 2002; 282:E703-13. [PMID: 11832376 DOI: 10.1152/ajpendo.00072.2001] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The effects of high-fat feeding on the development of obesity were evaluated in intercellular adhesion molecule-1 (ICAM-1) knockout and C57BL/6J (B6) male mice fed a high-fat diet for < or =50 days. Serum and tissues were collected at baseline and after 1, 11, and 50 days on the diet. After 11 days on the diet, ICAM-1-deficient, but not B6, mice developed fatty livers and showed a significant increase in inguinal fat pad weight. At day 50, ICAM-1-deficient mice weighed less, and their adiposity index and circulating leptin levels were significantly lower than those of B6 controls. To better understand the early differential response to the diet, liver gene expression was analyzed at three time points by use of Affymetrix GeneChips. In both strains, a similar pattern of gene expression was detected in response to the high-fat diet. However, sterol regulatory element-binding protein-1, apolipoprotein A4, and adipsin mRNAs were significantly induced in ICAM-1-deficient livers, suggesting that these genes and their associated pathways may be involved in the acute diet response observed in the knockout mice.
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39
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Peebles ED, Croom J, Maslin WR, Whitmarsh SK, Daniel LR, Taylor IL. In ovo peptide YY and epidermal growth factor administration and their effects on growth and yolk utilization in neonatal meat-type chickens (Gallus domesticus). Comp Biochem Physiol A Mol Integr Physiol 2001; 130:741-9. [PMID: 11691610 DOI: 10.1016/s1095-6433(01)00406-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The effects of in ovo peptide YY (PYY) or epidermal growth factor (EGF) administration on chick growth, yolk absorption and yolk stalk function in posthatch (0-5 days) meat-type or broiler chicks were determined. At Day 18 of incubation, treated eggs were injected into the air cell with 100 microl of either PYY (Trial 1) or EGF (Trial 2) at a dosage of 600 microg/kg egg weight. Saline-treated control eggs were injected similarly with 0.9% saline. At hatch, 200 microl of (51)Cr-labeled microspheres were injected into chick yolk sacs. Epidermal growth factor increased ileal wet weight adjusted for body weight as well as ileal serosal dry matter. Body weight, feed consumption and excreta weight per bird, and relative weights of the yolk sac, intestine and liver were significantly affected by age of the chick in both trials. Relative radioactivity of the yolk sac, yolk stalk, blood, liver, and kidneys were affected by bird age in Trial 2; however, there were no significant effects due to PYY or EGF treatments on relative radioactivity of the tissues and organs examined. These data suggest that PYY and EGF had no effect on yolk absorption or yolk stalk function through 5 days in the posthatch chick.
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Affiliation(s)
- E D Peebles
- Department of Poultry Science, Mississippi State University, Mississippi State, MS 39762, USA.
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40
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Cuche G, Blat S, Malbert CH. Desensitization of ileal vagal receptors by short-chain fatty acids in pigs. Am J Physiol Gastrointest Liver Physiol 2001; 280:G1013-21. [PMID: 11292611 DOI: 10.1152/ajpgi.2001.280.5.g1013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Coloileal reflux episodes trigger specialized ileal motor activities and inhibit gastric motility in pigs. The initiation of these events requires the detection by the distal ileum of the invading colonic contents that differ from the ileal chyme primarily in short-chain fatty acid (SCFA) concentrations. In addition to the already described humoral pathway, this detection might also involve ileal vagal afferents. Sensitivity to SCFA of 12 ileal vagal units was investigated in anesthetized pigs with single-unit recording at the left cervical vagus. SCFA mixtures (0.35, 0.7, and 1.4 mol/l) containing acetic, propionic, and butyric acids in proportions identical to that in the porcine cecocolon were compared with isotonic and hypertonic saline. All units behaved as slowly adapting mechanoreceptors (half-adaptation time = 35.4 +/- 15.89 s), and their sensitivity to local mechanical probing was suppressed by local anesthesia; 7 units significantly decreased their spontaneous firing with 0.7 and 1.4 but not 0.35 mol/l SCFA infusion compared with hypertonic or isotonic saline. Similarly, the response induced by distension in the same seven units was reduced (5 neurons) or abolished (2 neurons) after infusion of 0.7 (22.8 +/- 2.39 impulses/s) and 1.4 (30.3 +/- 2.12 impulses/s) mol/l SCFA solutions compared with isotonic saline (38.6 +/- 4.09 impulses/s). These differences in discharge were not the result of changes in ileal compliance, which remained constant after SCFA. In conclusion, SCFA, at concentrations near those found during coloileal reflux episodes, reduced or abolished mechanical sensitivity of ileal vagal afferents.
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Affiliation(s)
- G Cuche
- Unité Mixte de Recherches sur le Veau et le Porc, Institut National de la Recherche Agronomique, 35590 Saint-Gilles, France
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Kalogeris TJ, Painter RG. Adaptation of intestinal production of apolipoprotein A-IV during chronic feeding of lipid. Am J Physiol Regul Integr Comp Physiol 2001; 280:R1155-61. [PMID: 11247839 DOI: 10.1152/ajpregu.2001.280.4.r1155] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the effect of daily fat supplementation on intestinal gene expression and protein synthesis and plasma levels of apolipoprotein A-IV (apo A-IV). Rats were fasted overnight and then given intragastric bolus infusion of either saline or fat emulsion after 0, 1, 2, 4, 8, or 16 days of similar daily feedings. Four hours after the final saline or fat infusion, plasma and jejunal mucosa were harvested; plasma levels of apo A-IV, triglycerides, and leptin were measured, as well as mucosal apo A-IV mRNA levels and biosynthesis of apo A-IV protein. In response to fat, plasma apo A-IV showed an initial 40% increase compared with saline-injected control rats; with continued daily fat feeding, the plasma A-IV response showed rapid and progressive diminution such that by 4 days, plasma A-IV was not different between fat- and saline-fed groups. Jejunal mucosal apo A-IV synthesis and mRNA levels also showed time-dependent refractoriness to fat feeding. However, the kinetics of this effect were considerably slower than in the case of plasma, requiring 16 days for completion. There was no correlation between plasma leptin or triglyceride levels and intestinal apo A-IV synthesis or plasma apo A-IV. These results indicate rapid, fat-induced, posttranslational adapation of plasma apo A-IV levels and a slower, but similarly complete pretranslational adaptation of intestinal apo A-IV production, which are independent of plasma levels of leptin.
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Affiliation(s)
- T J Kalogeris
- Department of Surgery, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130, USA.
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Hockey KJ, Anderson RA, Cook VR, Hantgan RR, Weinberg RB. Effect of the apolipoprotein A-IV Q360H polymorphism on postprandial plasma triglyceride clearance. J Lipid Res 2001. [DOI: 10.1016/s0022-2275(20)31681-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Dynamic interfacial properties of human apolipoproteins A-IV and B-17 at the air/water and oil/water interface. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)33454-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Kalogeris TJ, Painter RG, Holden VR. Ileal lipid infusion stimulates jejunal synthesis of apolipoprotein A-IV without affecting mRNA levels. PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE. SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE (NEW YORK, N.Y.) 2000; 223:198-202. [PMID: 10654624 DOI: 10.1046/j.1525-1373.2000.22327.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We examined the effect of ileal infusions of lipid emulsion on mRNA levels and biosynthesis of apolipoprotein A-IV (apo A-IV) in jejunal Thiry-Vella fistulas in rats. The rats were surgically prepared with jejunal Thiry-Vella fistulas; after recovery they were deprived of food, equipped with ileal infusion cannulas, then given 8 hr ileal infusions of fatty acid/monoglyceride emulsions. Mucosal synthesis and transcript levels of apo A-IV in the Thiry-Vella loop were then measured. Lipid infusion produced a two-fold stimulation in incorporation of 3H-leucine into apo A-IV-specific protein, but had no significant effect on apo A-IV mRNA levels. These results support the hypothesis that a lipid-elicited, distal gut-derived, systemic signal stimulates the production of apo A-IV by a post-transcriptional mechanism.
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Affiliation(s)
- T J Kalogeris
- Department of Surgery, Louisiana State University Medical Center, Shreveport 71130, USA.
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Kalogeris TJ, Holden VR, Tso P. Stimulation of jejunal synthesis of apolipoprotein A-IV by ileal lipid infusion is blocked by vagotomy. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:G1081-7. [PMID: 10564115 DOI: 10.1152/ajpgi.1999.277.5.g1081] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
We examined the role of vagal innervation in lipid-stimulated increases in expression and synthesis of intestinal apolipoprotein A-IV (apoA-IV). In rats with duodenal cannulas and superior mesenteric lymph fistulas given duodenal infusions of lipid emulsion, vagotomy had no effect on either intestinal lipid transport, lymphatic apoA-IV output, or jejunal mucosal apoA-IV synthesis. In rats with jejunal Thiry-Vella fistulas, ileal lipid infusion elicited a twofold stimulation of apoA-IV synthesis without affecting apoA-IV mRNA levels; vagotomy blocked this increase in apoA-IV synthesis. Direct perfusion of jejunal Thiry-Vella fistulas produced 2- to 2.5-fold increases in both apoA-IV synthesis and mRNA levels in the Thiry-Vella segment; these effects were not influenced by vagal denervation. These results suggest two mechanisms whereby lipid stimulates intestinal apoA-IV production: 1) a vagal-dependent stimulation of jejunal apoA-IV synthesis by distal gut lipid that is independent of changes in apoA-IV mRNA levels and 2) a direct stimulatory effect of proximal gut lipid on both synthesis and mRNA levels of jejunal apoA-IV that is independent of vagal innervation.
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Affiliation(s)
- T J Kalogeris
- Department of Surgery, Louisiana State University Medical Center, Shreveport, Louisiana 71130, USA.
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Weinberg RB. Apolipoprotein A-IV-2 allele: association of its worldwide distribution with adult persistence of lactase and speculation on its function and origin. Genet Epidemiol 1999; 17:285-97. [PMID: 10520211 DOI: 10.1002/(sici)1098-2272(199911)17:4<285::aid-gepi4>3.0.co;2-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Apolipoprotein A-IV (apo A-IV) is a 46-Kd plasma glycoprotein that may play a major role in intestinal lipid absorption. A genetic polymorphism in the apo A-IV gene, apo A-IV-2, encodes a His-->Gln substitution at codon 360 that alters the biological function of this apolipoprotein. As the worldwide distribution of the apo A-IV-2 allele appeared similar to the frequency of a genetic polymorphism that determines the persistence of lactase into adulthood, we examined the relationship between the apo A-IV-2 and lactase persistence polymorphisms by compiling the prevalence of adult lactase persistence in all populations in which the frequency of the apo A-IV-2 allele has been determined. Across 29 groups, there was an extremely strong correlation (4 = 0.937, P < 0.000001) between apo A-IV-2 allele frequency and the prevalence of adult lactase persistence. Apo A-IV-2 allele frequency was highest in Iceland, an ancient Viking colony, and decreased across Europe in a north-to-south and west-to-east gradient, generally following hypothetical isoclines for the lactase persistence gene. There were no correlations between the population frequencies of the apo E2, E3, or E4 alleles and either the prevalence of lactase persistence or the frequency of the apo A-IV-2 allele. In light of the effects of the apo A-IV-2 polymorphism on lipid metabolism, we speculate that the apo A-IV-2 allele may have originated in ancient Scandinavia, spread by conferring a nutritional advantage in the setting of a lifelong high milkfat intake, and was later carried southwards by the Viking incursions into Europe.
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Affiliation(s)
- R B Weinberg
- Section of Gastroenterology, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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Raybould HE. Nutrient tasting and signaling mechanisms in the gut. I. Sensing of lipid by the intestinal mucosa. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:G751-5. [PMID: 10516140 DOI: 10.1152/ajpgi.1999.277.4.g751] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
It is well recognized that lipid in the intestine is a potent inhibitor of gastric secretomotor function. Progress has been made in the identification of the "sensor" for lipid in the intestinal wall. Long-chain free fatty acids are the stimulus both for release of CCK and for the production of functional effects. Long-chain triglyceride requires chylomicron formation for absorption, and there is strong evidence that the postabsorptive products of long-chain triglyceride absorption, including chylomicrons and apolipoproteins, are involved in sensory transduction in the intestinal wall.
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Affiliation(s)
- H E Raybould
- CURE: Digestive Diseases Research Center, West Los Angeles Veterans Affairs Medical Center, Los Angeles, California 90095, USA.
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Rubin DC. Nutrient regulation of intestinal growth and adaptation: role of glucagon-like peptide 2 and the enteroendocrine cell. Gastroenterology 1999; 117:261-3. [PMID: 10381936 DOI: 10.1016/s0016-5085(99)70576-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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