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Murakami M, Sato H, Taketomi Y. Modulation of immunity by the secreted phospholipase A 2 family. Immunol Rev 2023; 317:42-70. [PMID: 37035998 DOI: 10.1111/imr.13205] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/23/2023] [Accepted: 03/28/2023] [Indexed: 04/11/2023]
Abstract
Among the phospholipase A2 (PLA2 ) superfamily, which typically catalyzes the sn-2 hydrolysis of phospholipids to yield fatty acids and lysophospholipids, the secreted PLA2 (sPLA2 ) family contains 11 isoforms in mammals. Individual sPLA2 s have unique enzymatic specificity toward fatty acids and polar heads of phospholipid substrates and display distinct tissue/cellular distributions, suggesting their distinct physiological functions. Recent studies using knockout and/or transgenic mice for a full set of sPLA2 s have revealed their roles in modulation of immunity and related disorders. Application of mass spectrometric lipidomics to these mice has enabled to identify target substrates and products of individual sPLA2 s in given tissue microenvironments. sPLA2 s hydrolyze not only phospholipids in the plasma membrane of activated, damaged or dying mammalian cells, but also extracellular phospholipids such as those in extracellular vesicles, microbe membranes, lipoproteins, surfactants, and dietary phospholipids, thereby exacerbating or ameliorating various diseases. The actions of sPLA2 s are dependent on, or independent of, the generation of fatty acid- or lysophospholipid-derived lipid mediators according to the pathophysiological contexts. In this review, we make an overview of our current understanding of the roles of individual sPLA2 s in various immune responses and associated diseases.
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Affiliation(s)
- Makoto Murakami
- Laboratory of Microenvironmental and Metabolic Health Science, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan
| | - Hiroyasu Sato
- Laboratory of Microenvironmental and Metabolic Health Science, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yoshitaka Taketomi
- Laboratory of Microenvironmental and Metabolic Health Science, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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2
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Diet evolution of carnivorous and herbivorous mammals in Laurasiatheria. BMC Ecol Evol 2022; 22:82. [PMID: 35729512 PMCID: PMC9210794 DOI: 10.1186/s12862-022-02033-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 12/09/2021] [Indexed: 11/15/2022] Open
Abstract
Background Laurasiatheria contains taxa with diverse diets, while the molecular basis and evolutionary history underlying their dietary diversification are less clear. Results In this study, we used the recently developed molecular phyloecological approach to examine the adaptive evolution of digestive system-related genes across both carnivorous and herbivorous mammals within Laurasiatheria. Our results show an intensified selection of fat and/or protein utilization across all examined carnivorous lineages, which is consistent with their high-protein and high-fat diets. Intriguingly, for herbivorous lineages (ungulates), which have a high-carbohydrate diet, they show a similar selection pattern as that of carnivorous lineages. Our results suggest that for the ungulates, which have a specialized digestive system, the selection intensity of their digestive system-related genes does not necessarily reflect loads of the nutrient components in their diets but appears to be positively related to the loads of the nutrient components that are capable of being directly utilized by the herbivores themselves. Based on these findings, we reconstructed the dietary evolution within Laurasiatheria, and our results reveal the dominant carnivory during the early diversification of Laurasiatheria. In particular, our results suggest that the ancestral bats and the common ancestor of ruminants and cetaceans may be carnivorous as well. We also found evidence of the convergent evolution of one fat utilization-related gene, APOB, across carnivorous taxa. Conclusions Our molecular phyloecological results suggest that digestive system-related genes can be used to determine the molecular basis of diet differentiations and to reconstruct ancestral diets. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-022-02033-6.
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Identification of Genes Related to Squab Muscle Growth and Lipid Metabolism from Transcriptome Profiles of Breast Muscle and Liver in Domestic Pigeon (Columba livia). Animals (Basel) 2022; 12:ani12091061. [PMID: 35565488 PMCID: PMC9100022 DOI: 10.3390/ani12091061] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/11/2022] [Accepted: 04/18/2022] [Indexed: 02/01/2023] Open
Abstract
Simple Summary Domestic pigeon is an important small poultry species raised for high-quality meat production. However, the relevant gene associated with meat growth and lipid metabolism during the period from dehulling to marketing are not known. Therefore, we aim to identify genes related to squab muscle growth and lip metabolism from transcriptome profiles of breast muscle and liver in domestic pigeon. In this study, we totally found that 4465 differentially expressed genes (DEGs) identified in the breast muscle and liver libraries, which include 2585 genes that were up-regulated and 2122 genes that were down-regulated. Most genes are involved in cell proliferation and differentiation, lipid metabolism and energy metabolism according to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of DEGs. We also detected 16 DEGs to verify data from RNA-Seq and qPCR, which were consistent in quantitatively estimating the transcription levels of the tested transcripts by qPCR analysis. The results of this study will lay the foundation for understanding the mechanisms of muscle growth and lipid metabolism in domestic pigeons. Abstract The improvements in muscle growth rate and meat quality are the major breeding aims in pigeon industry. Liver and muscle are recognized as important sites for fatty acid metabolism; understanding the role of specific transcripts in the breast muscle and liver might lead to the elucidation of interrelated biological processes. In this study, RNA-Sequencing (RNA-Seq) was applied to compare the transcriptomes of breast muscle and liver tissues among pigeons at five developmental periods (0, 1, 2, 3, 4 weeks post-hatching) to identify candidate genes related to muscle growth and lipid metabolism. There were 3142 differentially expressed genes (DEGs) identified in the breast muscle libraries; 1794 genes were up-regulated while 1531 genes were down-regulated. A total of 1323 DEGs were acquired from the liver libraries, with 791 up-regulated genes and 591 down-regulated genes. By pathway enrichment analysis, a set of significantly enriched pathways were identified for the DEGs, which are potentially involved in cell proliferation and differentiation, lipid metabolism and energy metabolism in pigeon breast muscle and liver. Our results are consistent with previous partial reports from domestic animals and poultry and provide some unidentified genes involved in muscle growth and lipid metabolism. The reliability of the sequencing data was verified through qPCR analysis of 16 genes from eight comparison groups (two genes per group). The findings from this study could contribute to future investigations of muscle growth and lipid metabolism mechanisms and establish molecular approaches to improve muscle growth rate and meat quality in domestic pigeon breeding.
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Wang K, Wu J, Chen S, Zhao H, He P, Tu Y, Li B. Transcriptome analysis provides insights into the anti-diabetic mechanism of theaflavins in high-fat diet and streptozotocin-induced mice. Food Funct 2022; 13:2033-2043. [DOI: 10.1039/d1fo03856g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Black tea exhibits potential to improve hyperglycemia and insulin resistance, and theaflavins (TFs) are one of its characteristic components. The aim of this study was to explore the anti-diabetic mechanism...
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Wu W, Li WX, Huang CH. Phospholipase A 2, a nonnegligible enzyme superfamily in gastrointestinal diseases. Biochimie 2021; 194:79-95. [PMID: 34974145 DOI: 10.1016/j.biochi.2021.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 12/25/2021] [Accepted: 12/28/2021] [Indexed: 11/16/2022]
Abstract
Gastrointestinal tract is important for digestion, absorption, detoxification and immunity. Gastrointestinal diseases are mainly caused by the imbalance of protective and attacking factors in gastrointestinal mucosa, which can seriously harm human health. Phospholipase A2 (PLA2) is a large family closely involved in lipid metabolism and is found in almost all human cells. A growing number of studies have revealed that its metabolites are deeply implicated in various inflammatory pathways and also regulates the maintenance of numerous biological events such as dietary digestion, membrane remodeling, barrier action, and host immunity. In addition to their phospholipase activity, some members of the superfamily also have other catalytic activities. Based on the in-depth effects of phospholipase A2 on bioactive lipid metabolism and inflammatory cytokines, PLA2 and its metabolites are likely to be involved in the pathogenesis, development or prevention of gastrointestinal diseases. Therefore, this review will focus on the physiological and pathogenic roles of several important PLA2 enzymes in the gastrointestinal tract, and reveals the potential of PLA2 as a therapeutic target for gastrointestinal diseases.
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Affiliation(s)
- Wei Wu
- Queen Mary School, Medical Department, Nanchang University, Nanchang, Jiangxi, China
| | - Wen-Xuan Li
- Queen Mary School, Medical Department, Nanchang University, Nanchang, Jiangxi, China
| | - Chun-Hong Huang
- School of Basic Medical Sciences, 330006, Nanchang University, Nanchang, Jiangxi, China.
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Kuefner MS. Secretory Phospholipase A2s in Insulin Resistance and Metabolism. Front Endocrinol (Lausanne) 2021; 12:732726. [PMID: 34512555 PMCID: PMC8429832 DOI: 10.3389/fendo.2021.732726] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/09/2021] [Indexed: 01/01/2023] Open
Abstract
The phospholipases A2 (PLA2) superfamily encompasses enzymes commonly found in mammalian tissues and snake venom. Many of these enzymes have unique tissue distribution, function, and substrate specificity suggesting distinct biological roles. In the past, much of the research on secretory PLA2s has analyzed their roles in inflammation, anti-bacterial actions, and atherosclerosis. In recent studies utilizing a variety of mouse models, pancreatic islets, and clinical trials, a role for many of these enzymes in the control of metabolism and insulin action has been revealed. In this review, this research, and the unique contributions of the PLA2 enzymes in insulin resistance and metabolism.
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Rescue of Hepatic Phospholipid Remodeling Defectin iPLA2β-Null Mice Attenuates Obese but Not Non-Obese Fatty Liver. Biomolecules 2020; 10:biom10091332. [PMID: 32957701 PMCID: PMC7565968 DOI: 10.3390/biom10091332] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/15/2020] [Accepted: 09/15/2020] [Indexed: 12/19/2022] Open
Abstract
Polymorphisms of group VIA calcium-independent phospholipase A2 (iPLA2β or PLA2G6) are positively associated with adiposity, blood lipids, and Type-2 diabetes. The ubiquitously expressed iPLA2β catalyzes the hydrolysis of phospholipids (PLs) to generate a fatty acid and a lysoPL. We studied the role of iPLA2β on PL metabolism in non-alcoholic fatty liver disease (NAFLD). By using global deletion iPLA2β-null mice, we investigated three NAFLD mouse models; genetic Ob/Ob and long-term high-fat-diet (HFD) feeding (representing obese NAFLD) as well as feeding with methionine- and choline-deficient (MCD) diet (representing non-obese NAFLD). A decrease of hepatic PLs containing monounsaturated- and polyunsaturated fatty acids and a decrease of the ratio between PLs and cholesterol esters were observed in all three NAFLD models. iPLA2β deficiency rescued these decreases in obese, but not in non-obese, NAFLD models. iPLA2β deficiency elicited protection against fatty liver and obesity in the order of Ob/Ob › HFD » MCD. Liver inflammation was not protected in HFD NAFLD, and that liver fibrosis was even exaggerated in non-obese MCD model. Thus, the rescue of hepatic PL remodeling defect observed in iPLA2β-null mice was critical for the protection against NAFLD and obesity. However, iPLA2β deletion in specific cell types such as macrophages may render liver inflammation and fibrosis, independent of steatosis protection.
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sPLA2-IB Level Correlates with Hyperlipidemia and the Prognosis of Idiopathic Membranous Nephropathy. Curr Med Sci 2020; 40:683-690. [PMID: 32862379 DOI: 10.1007/s11596-020-2246-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 06/30/2020] [Indexed: 10/23/2022]
Abstract
Recent studies suggested that serum secretory phospholipase A2 group IB (sPLA2-IB) was increased in idiopathic membranous nephropathy (IMN). However, the interference of high lipemia on the sPLA2-IB levels was not taken into account in these studies. The present study aimed to investigate the correlation between sPLA2-IB and lipemia, and the clinical merit of sPLA2-IB in the prediction of prognosis of IMN patients. A total of 64 IMN patients, 39 immunoglobulin A nephropathy (IgAN) patients and 64 healthy controls were included in the study. The levels of serum sPLA2-IB, lipemia and proteinuria were measured. Fifty IMN patients were followed up for 6 months. Pathologic stages were made for all IgAN and IMN patients. The results showed that the levels of serum sPLA2-IB, cholesterol and low-density lipoprotein cholesterol (LDL-C) were significantly higher, and the levels of albumin and high-density lipoprotein cholesterol (HDL-C) were significantly lower in IMN patients than in healthy controls and IgAN patients. Serum sPLA2-IB levels were also found to be higher in IgAN patients than in heathy controls, but the association of serum sPLA2-IB levels with proteinuria, cholesterol and albumin was only shown in IMN patients. Antibody against M-type receptor for secretory phospholipase A2 (PLA2R1) was positive in 81.3% IMN patients. Glomerular sPLA2-IB deposition, podocyte fused processes, and density deposition on thickened basement membrane were seen in IMN patients, but not in IgAN patients. IMN patients with lower sPLA2-IB and proteinuria levels were found to have better outcome after the 6-month follow-up. In IMN patients, sPLA2-IB levels were significantly increased in both serum and renal tissue. In conclusion, serum sPLA2-IB was closely correlated with proteinuria, albumin and cholesterol, and IMN patients with lower sPLA2-IB levels were more likely to achieve a better outcome.
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Nishiumi S, Izumi Y, Kobayashi T, Yoshida M. Possible Involvement of Lipids in the Effectiveness of Kombu in Individuals with Abnormally High Serum Triglyceride Levels. J Nutr Sci Vitaminol (Tokyo) 2020; 66:185-190. [PMID: 32350180 DOI: 10.3177/jnsv.66.185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In Japan, Kombu (Laminaria japonica), which is a type of seaweed, is considered to be a foodstuff with health-promoting benefits, and Japanese people actively incorporate Kombu into their diets. Previously, we reported that the frequent intake of Kombu reduced the serum triglyceride levels of subjects with abnormally high serum triglyceride levels. In the current human study, we performed metabolomic analysis of serum lipids, and then the molecular species profiles of phosphatidylcholines (PC), phosphatidylethanolamines (PE), lysophosphatidylcholines (LPC), lysophosphatidylethanolamines (LPE), and free fatty acids (FFA) were evaluated. As a result, it was found that there were no marked differences between the lipid profiles obtained before and after the intake of Kombu for 4 wk in all subjects. In the subjects with abnormal serum triglyceride levels, the intake of Kombu improved the subjects' molecular species profiles in terms of their serum levels of the diacyl and acyl forms of PC, PE, LPC, and LPE, and FFA. Furthermore, the intake of Kombu also tended to increase the serum levels of both the plasmanyl and plasmenyl forms of PC and PE in these subjects. The lipid alterations observed in our study might be related to the functionality of Kombu. Furthermore, it is important to evaluate the quality of lipids as well as the quantity of lipids in various types of research, including food functionality studies.
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Affiliation(s)
- Shin Nishiumi
- Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine
- Department of Omics Medicine, Hyogo College of Medicine
| | - Yoshihiro Izumi
- Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine
| | - Takashi Kobayashi
- Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine
| | - Masaru Yoshida
- Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine
- Division of Metabolomics Research, Department of Internal Medicine Related, Kobe University Graduate School of Medicine
- AMED-CREST, AMED
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Son A, Ahuja M, Schwartz DM, Varga A, Swaim W, Kang N, Maleth J, Shin DM, Muallem S. Ca 2+ Influx Channel Inhibitor SARAF Protects Mice From Acute Pancreatitis. Gastroenterology 2019; 157:1660-1672.e2. [PMID: 31493399 DOI: 10.1053/j.gastro.2019.08.042] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 08/06/2019] [Accepted: 08/08/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Pancreatitis is characterized by increased influx of Ca2+ into acinar cells, by unknown mechanisms. Inhibitors of Ca2+ influx channels could be effective in treating acute pancreatitis, but these have deleterious side effects that can result in death. We investigated the expression patterns and functions of acinar cell Ca2+ channels and factors that regulate them during development of acute pancreatitis, along with changes in the channel inactivator store-operated calcium entry-associated regulatory factor (SARAF). We investigated whether SARAF is a target for treatment of acute pancreatitis and its status in human with pancreatitis. METHODS We generated mice that expressed SARAF tagged with hemagglutinin, using CRISPR/Cas9 gene editing, and isolated acinar cells. We also performed studies with Saraf-/- mice, Sarafzf/zf mice, mice without disruption of Saraf (control mice), and mice that overexpress fluorescently labeled SARAF in acinar cells. We analyzed interactions between stromal interaction molecule 1 (STIM1) and SARAF in HEK cells stimulated with carbachol using fluorescence resonance energy transfer microscopy and immunoprecipitation. Mice were given injections of caerulein or L-arginine to induce pancreatitis. Pancreatic tissues and blood samples were collected and levels of serum amylase, trypsin, tissue damage, inflammatory mediators, and inflammatory cells were measured. We performed quantitative polymerase chain reaction analyses of pancreatic tissues from 6 organ donors without pancreatic disease (controls) and 8 patients with alcohol-associated pancreatitis. RESULTS Pancreatic levels of Ca2+ influx channels or STIM1 did not differ significantly between acinar cells from mice with vs. without pancreatitis. By contrast, pancreatic levels of Saraf messenger RNA and SARAF protein initially markedly increased but then decreased during cell stimulation or injection of mice with caerulein, resulting in excessive Ca2+ influx. STIM1 interacted stably with SARAF following stimulation of HEK or mouse acinar cells with physiologic levels of carbachol, but only transiently following stimulation with pathologic levels of carbachol, leading to excessive Ca2+ influx. We observed reduced levels of SARAF messenger RNA in pancreatic tissues from patients with pancreatitis, compared with controls. SARAF knockout mice developed more severe pancreatitis than control mice after administration of caerulein or L-arginine, and pancreatic acinar cells from these mice had significant increases in Ca2+ influx. Conversely, overexpression of SARAF in acini reduced Ca2+ influx, eliminated inflammation, and reduced severity of acute pancreatitis. CONCLUSIONS In mice with pancreatitis, SARAF initially increases but is then degraded, resulting in excessive, pathological Ca2+ influx by acinar cells. SARAF knockout mice develop more severe pancreatitis than control mice, whereas mice that express SARAF from a transgene in acinar cells develop less-severe pancreatitis. SARAF therefore appears to prevent pancreatic damage during development of acute pancreatitis. Strategies to stabilize or restore SARAF to acinar cells might be developed for treatment of pancreatitis.
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Affiliation(s)
- Aran Son
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Malini Ahuja
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Daniella M Schwartz
- Genetics and Pathogenesis of Allergy Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Arpad Varga
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, First Department of Medicine, University of Szeged, Szeged, Hungary
| | - William Swaim
- NIDCR imaging core, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Namju Kang
- Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul, South Korea
| | - Jozsef Maleth
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, First Department of Medicine, University of Szeged, Szeged, Hungary
| | - Dong Min Shin
- Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul, South Korea.
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland.
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Nilsson Å, Duan RD. Pancreatic and mucosal enzymes in choline phospholipid digestion. Am J Physiol Gastrointest Liver Physiol 2019; 316:G425-G445. [PMID: 30576217 DOI: 10.1152/ajpgi.00320.2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The digestion of choline phospholipids is important for choline homeostasis, lipid signaling, postprandial lipid and energy metabolism, and interaction with intestinal bacteria. The digestion is mediated by the combined action of pancreatic and mucosal enzymes. In the proximal small intestine, hydrolysis of phosphatidylcholine (PC) to 1-lyso-PC and free fatty acid (FFA) by the pancreatic phospholipase A2 IB coincides with the digestion of the dietary triacylglycerols by lipases, but part of the PC digestion is extended and must be mediated by other enzymes as the jejunoileal brush-border phospholipase B/lipase and mucosal secreted phospholipase A2 X. Absorbed 1-lyso-PC is partitioned in the mucosal cells between degradation and reacylation into chyle PC. Reutilization of choline for hepatic bile PC synthesis, and the reacylation of 1-lyso-PC into chylomicron PC by the lyso-PC-acyl-CoA-acyltransferase 3 are important features of choline recycling and postprandial lipid metabolism. The role of mucosal enzymes is emphasized by sphingomyelin (SM) being sequentially hydrolyzed by brush-border alkaline sphingomyelinase (alk-SMase) and neutral ceramidase to sphingosine and FFA, which are well absorbed. Ceramide and sphingosine-1-phosphate are generated and are both metabolic intermediates and important lipid messengers. Alk-SMase has anti-inflammatory effects that counteract gut inflammation and tumorigenesis. These may be mediated by multiple mechanisms including generation of sphingolipid metabolites and suppression of autotaxin induction and lyso-phosphatidic acid formation. Here we summarize current knowledge on the roles of pancreatic and mucosal enzymes in PC and SM digestion, and its implications in intestinal and liver diseases, bacterial choline metabolism in the gut, and cholesterol absorption.
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Affiliation(s)
- Åke Nilsson
- Department of Clow-linical Sciences Lund, Division of Medicine, Gastroenterology, Lund University , Lund , Sweden
| | - Rui-Dong Duan
- Gastroenterology and Nutrition Laboratory, Department of Clinical Sciences, Lund University , Lund , Sweden
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Wang W, Jiang W, Hou L, Duan H, Wu Y, Xu C, Tan Q, Li S, Zhang D. Weighted gene co-expression network analysis of expression data of monozygotic twins identifies specific modules and hub genes related to BMI. BMC Genomics 2017; 18:872. [PMID: 29132311 PMCID: PMC5683603 DOI: 10.1186/s12864-017-4257-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 11/01/2017] [Indexed: 02/08/2023] Open
Abstract
Background The therapeutic management of obesity is challenging, hence further elucidating the underlying mechanisms of obesity development and identifying new diagnostic biomarkers and therapeutic targets are urgent and necessary. Here, we performed differential gene expression analysis and weighted gene co-expression network analysis (WGCNA) to identify significant genes and specific modules related to BMI based on gene expression profile data of 7 discordant monozygotic twins. Results In the differential gene expression analysis, it appeared that 32 differentially expressed genes (DEGs) were with a trend of up-regulation in twins with higher BMI when compared to their siblings. Categories of positive regulation of nitric-oxide synthase biosynthetic process, positive regulation of NF-kappa B import into nucleus, and peroxidase activity were significantly enriched within GO database and NF-kappa B signaling pathway within KEGG database. DEGs of NAMPT, TLR9, PTGS2, HBD, and PCSK1N might be associated with obesity. In the WGCNA, among the total 20 distinct co-expression modules identified, coral1 module (68 genes) had the strongest positive correlation with BMI (r = 0.56, P = 0.04) and disease status (r = 0.56, P = 0.04). Categories of positive regulation of phospholipase activity, high-density lipoprotein particle clearance, chylomicron remnant clearance, reverse cholesterol transport, intermediate-density lipoprotein particle, chylomicron, low-density lipoprotein particle, very-low-density lipoprotein particle, voltage-gated potassium channel complex, cholesterol transporter activity, and neuropeptide hormone activity were significantly enriched within GO database for this module. And alcoholism and cell adhesion molecules pathways were significantly enriched within KEGG database. Several hub genes, such as GAL, ASB9, NPPB, TBX2, IL17C, APOE, ABCG4, and APOC2 were also identified. The module eigengene of saddlebrown module (212 genes) was also significantly correlated with BMI (r = 0.56, P = 0.04), and hub genes of KCNN1 and AQP10 were differentially expressed. Conclusion We identified significant genes and specific modules potentially related to BMI based on the gene expression profile data of monozygotic twins. The findings may help further elucidate the underlying mechanisms of obesity development and provide novel insights to research potential gene biomarkers and signaling pathways for obesity treatment. Further analysis and validation of the findings reported here are important and necessary when more sample size is acquired. Electronic supplementary material The online version of this article (10.1186/s12864-017-4257-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Weijing Wang
- Department of Epidemiology and Health Statistics, Public Health College, Qingdao University, No. 38 Dengzhou Road, Shibei District, Qingdao, 266021, Shandong Province, People's Republic of China
| | - Wenjie Jiang
- Department of Epidemiology and Health Statistics, Public Health College, Qingdao University, No. 38 Dengzhou Road, Shibei District, Qingdao, 266021, Shandong Province, People's Republic of China
| | - Lin Hou
- Department of Biochemistry, Medical College, Qingdao University, No. 38 Dengzhou Road, Shibei District, Qingdao, 266021, Shandong Province, People's Republic of China
| | - Haiping Duan
- Department of Epidemiology and Health Statistics, Public Health College, Qingdao University, No. 38 Dengzhou Road, Shibei District, Qingdao, 266021, Shandong Province, People's Republic of China.,Qingdao Municipal Center for Disease Control and Prevention, No. 175 Shandong Road, Shibei District, Qingdao, 266033, Shandong Province, People's Republic of China
| | - Yili Wu
- Department of Epidemiology and Health Statistics, Public Health College, Qingdao University, No. 38 Dengzhou Road, Shibei District, Qingdao, 266021, Shandong Province, People's Republic of China
| | - Chunsheng Xu
- Department of Epidemiology and Health Statistics, Public Health College, Qingdao University, No. 38 Dengzhou Road, Shibei District, Qingdao, 266021, Shandong Province, People's Republic of China.,Qingdao Municipal Center for Disease Control and Prevention, No. 175 Shandong Road, Shibei District, Qingdao, 266033, Shandong Province, People's Republic of China.,Qingdao Institute of Preventive Medicine, No. 175 Shandong Road, Shibei District, Qingdao, 266033, Shandong Province, People's Republic of China
| | - Qihua Tan
- Epidemiology, Biostatistics and Bio-demography, Institute of Public Health, University of Southern Denmark, DK-5000, Odense C, Denmark.,Human Genetics, Institute of Clinical Research, University of Southern Denmark, DK-5000, Odense C, Denmark
| | - Shuxia Li
- Human Genetics, Institute of Clinical Research, University of Southern Denmark, DK-5000, Odense C, Denmark
| | - Dongfeng Zhang
- Department of Epidemiology and Health Statistics, Public Health College, Qingdao University, No. 38 Dengzhou Road, Shibei District, Qingdao, 266021, Shandong Province, People's Republic of China.
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Murakami M, Yamamoto K, Miki Y, Murase R, Sato H, Taketomi Y. The Roles of the Secreted Phospholipase A 2 Gene Family in Immunology. Adv Immunol 2016; 132:91-134. [PMID: 27769509 PMCID: PMC7112020 DOI: 10.1016/bs.ai.2016.05.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Within the phospholipase A2 (PLA2) family that hydrolyzes phospholipids to yield fatty acids and lysophospholipids, secreted PLA2 (sPLA2) enzymes comprise the largest group containing 11 isoforms in mammals. Individual sPLA2s exhibit unique tissue or cellular distributions and enzymatic properties, suggesting their distinct biological roles. Although PLA2 enzymes, particularly cytosolic PLA2 (cPLA2α), have long been implicated in inflammation by driving arachidonic acid metabolism, the precise biological roles of sPLA2s have remained a mystery over the last few decades. Recent studies employing mice gene-manipulated for individual sPLA2s, in combination with mass spectrometric lipidomics to identify their target substrates and products in vivo, have revealed their roles in diverse biological events, including immunity and associated disorders, through lipid mediator-dependent or -independent processes in given microenvironments. In this review, we summarize our current knowledge of the roles of sPLA2s in various immune responses and associated diseases.
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Affiliation(s)
- M Murakami
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan; AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan.
| | - K Yamamoto
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan; Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan
| | - Y Miki
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - R Murase
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - H Sato
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Y Taketomi
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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Sato H, Taketomi Y, Murakami M. Metabolic regulation by secreted phospholipase A 2. Inflamm Regen 2016; 36:7. [PMID: 29259680 PMCID: PMC5725825 DOI: 10.1186/s41232-016-0012-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 05/10/2016] [Indexed: 12/18/2022] Open
Abstract
Within the phospholipase A2 (PLA2) superfamily that hydrolyzes phospholipids to yield fatty acids and lysophospholipids, the secreted PLA2 (sPLA2) enzymes comprise the largest family that contains 11 isoforms in mammals. Individual sPLA2s exhibit unique distributions and specific enzymatic properties, suggesting their distinct biological roles. While sPLA2s have long been implicated in inflammation and atherosclerosis, it has become evident that they are involved in diverse biological events through lipid mediator-dependent or mediator-independent processes in a given microenvironment. In recent years, new biological aspects of sPLA2s have been revealed using their transgenic and knockout mouse models in combination with mass spectrometric lipidomics to unveil their target substrates and products in vivo. In this review, we summarize our current knowledge of the roles of sPLA2s in metabolic disorders including obesity, hepatic steatosis, diabetes, insulin resistance, and adipose tissue inflammation.
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Affiliation(s)
- Hiroyasu Sato
- Lipid Metabolism Project, The Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506 Japan
| | - Yoshitaka Taketomi
- Lipid Metabolism Project, The Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506 Japan
| | - Makoto Murakami
- Lipid Metabolism Project, The Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506 Japan.,AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, 100-0004 Japan
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Murakami M, Sato H, Miki Y, Yamamoto K, Taketomi Y. A new era of secreted phospholipase A₂. J Lipid Res 2015; 56:1248-61. [PMID: 25805806 DOI: 10.1194/jlr.r058123] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Indexed: 12/18/2022] Open
Abstract
Among more than 30 members of the phospholipase A2 (PLA2) superfamily, secreted PLA2 (sPLA2) enzymes represent the largest family, being Ca(2+)-dependent low-molecular-weight enzymes with a His-Asp catalytic dyad. Individual sPLA2s exhibit unique tissue and cellular distributions and enzymatic properties, suggesting their distinct biological roles. Recent studies using transgenic and knockout mice for nearly a full set of sPLA2 subtypes, in combination with sophisticated lipidomics as well as biochemical and cell biological studies, have revealed distinct contributions of individual sPLA2s to various pathophysiological events, including production of pro- and anti-inflammatory lipid mediators, regulation of membrane remodeling, degradation of foreign phospholipids in microbes or food, or modification of extracellular noncellular lipid components. In this review, we highlight the current understanding of the in vivo functions of sPLA2s and the underlying lipid pathways as revealed by a series of studies over the last decade.
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Affiliation(s)
- Makoto Murakami
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan CREST, Japan Science and Technology Agency, Saitama 332-0012, Japan
| | - Hiroyasu Sato
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Yoshimi Miki
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Kei Yamamoto
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Yoshitaka Taketomi
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
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Levy E. Insights from human congenital disorders of intestinal lipid metabolism. J Lipid Res 2014; 56:945-62. [PMID: 25387865 DOI: 10.1194/jlr.r052415] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Indexed: 12/24/2022] Open
Abstract
The intestine must challenge the profuse daily flux of dietary fat that serves as a vital source of energy and as an essential component of cell membranes. The fat absorption process takes place in a series of orderly and interrelated steps, including the uptake and translocation of lipolytic products from the brush border membrane to the endoplasmic reticulum, lipid esterification, Apo synthesis, and ultimately the packaging of lipid and Apo components into chylomicrons (CMs). Deciphering inherited disorders of intracellular CM elaboration afforded new insight into the key functions of crucial intracellular proteins, such as Apo B, microsomal TG transfer protein, and Sar1b GTPase, the defects of which lead to hypobetalipoproteinemia, abetalipoproteinemia, and CM retention disease, respectively. These "experiments of nature" are characterized by fat malabsorption, steatorrhea, failure to thrive, low plasma levels of TGs and cholesterol, and deficiency of liposoluble vitamins and essential FAs. After summarizing and discussing the functions and regulation of these proteins for reader's comprehension, the current review focuses on their specific roles in malabsorptions and dyslipidemia-related intestinal fat hyperabsorption while dissecting the spectrum of clinical manifestations and managements. The influence of newly discovered proteins (proprotein convertase subtilisin/kexin type 9 and angiopoietin-like 3 protein) on fat absorption has also been provided. Finally, it is stressed how the overexpression or polymorphism status of the critical intracellular proteins promotes dyslipidemia and cardiometabolic disorders.
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Affiliation(s)
- Emile Levy
- Research Centre, CHU Sainte-Justine and Department of Nutrition, Université de Montréal, Montreal, Quebec H3T 1C5, Canada
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Quach ND, Arnold RD, Cummings BS. Secretory phospholipase A2 enzymes as pharmacological targets for treatment of disease. Biochem Pharmacol 2014; 90:338-48. [PMID: 24907600 DOI: 10.1016/j.bcp.2014.05.022] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 05/28/2014] [Accepted: 05/28/2014] [Indexed: 02/03/2023]
Abstract
Phospholipase A2 (PLA2) cleave phospholipids preferentially at the sn-2 position, liberating free fatty acids and lysophospholipids. They are classified into six main groups based on size, location, function, substrate specificity and calcium requirement. These classes include secretory PLA2 (sPLA2), cytosolic (cPLA2), Ca(2+)-independent (iPLA2), platelet activating factor acetylhydrolases (PAF-AH), lysosomal PLA2 (LyPLA2) and adipose specific PLA2 (AdPLA2). It is hypothesized that PLA2 can serve as pharmacological targets for the therapeutic treatment of several diseases, including cardiovascular diseases, atherosclerosis, immune disorders and cancer. Special emphasis has been placed on inhibitors of sPLA2 isoforms as pharmacological moieties, mostly due to the fact that these enzymes are activated during inflammatory events and because their expression is increased in several diseases. This review focuses on understanding how sPLA2 isoform expression is altered during disease progression and the possible therapeutic interventions to specifically target sPLA2 isoforms, including new approaches using nano-particulate-based strategies.
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Affiliation(s)
- Nhat D Quach
- Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA 30602, United States
| | - Robert D Arnold
- Department of Drug Discovery & Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849-5503, United States
| | - Brian S Cummings
- Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA 30602, United States.
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Hollie NI, Konaniah ES, Goodin C, Hui DY. Group 1B phospholipase A₂ inactivation suppresses atherosclerosis and metabolic diseases in LDL receptor-deficient mice. Atherosclerosis 2014; 234:377-80. [PMID: 24747111 PMCID: PMC4037866 DOI: 10.1016/j.atherosclerosis.2014.03.027] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/22/2014] [Accepted: 03/24/2014] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Previous studies have shown that inactivation of the group 1B phospholipase A2 (Pla2g1b) suppresses diet-induced obesity, hyperglycemia, insulin resistance, and hyperlipidemia in C57BL/6 mice. A possible influence of Pla2g1b inactivation on atherosclerosis has not been addressed previously. The current study utilized LDL receptor-deficient (Ldlr(-/-)) mice with plasma lipid levels and distribution similar to hyperlipidemic human subjects as a preclinical animal model to test the effectiveness of Pla2g1b inactivation on atherosclerosis. METHODS AND RESULTS The Pla2g1b(+/+)Ldlr(-/-) and Pla2g1b(-/-)Ldlr(-/-) mice were fed a low fat chow diet or a hypercaloric diet with 58.5 kcal% fat and 25 kcal% sucrose for 10 weeks. Minimal differences were observed between Pla2g1b(+/+)Ldlr(-/-) and Pla2g1b(-/-)Ldlr(-/-) mice when the animals were maintained on the low fat chow diet. However, when the animals were maintained on the hypercaloric diet, the Pla2g1(+/+)Ldlr(-/-) mice showed the expected body weight gain but the Pla2g1b(-/-)Ldlr(-/-) mice were resistant to diet-induced body weight gain. The Pla2g1b(-/-)Ldlr(-/-) mice also displayed lower fasting glucose, insulin, and plasma lipid levels compared to the Pla2g1b(+/+)Ldlr(-/-) mice, which displayed robust hyperglycemia, hyperinsulinemia, and hyperlipidemia in response to the hypercaloric diet. Importantly, atherosclerotic lesions in the aortic roots were also reduced 7-fold in the Pla2g1b(-/-)Ldlr(-/-) mice. CONCLUSION The effectiveness of Pla2g1b inactivation to suppress diet-induced body weight gain and reduce diabetes and atherosclerosis in LDL receptor-deficient mice suggests that pharmacological inhibition of Pla2g1b may be a viable strategy to decrease diet-induced obesity and the risk of diabetes and atherosclerosis in humans.
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Affiliation(s)
- Norris I Hollie
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA
| | - Eddy S Konaniah
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA
| | - Colleen Goodin
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA
| | - David Y Hui
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA.
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Cash JG, Kuhel DG, Basford JE, Jaeschke A, Chatterjee TK, Weintraub NL, Hui DY. Apolipoprotein E4 impairs macrophage efferocytosis and potentiates apoptosis by accelerating endoplasmic reticulum stress. J Biol Chem 2012; 287:27876-84. [PMID: 22730380 DOI: 10.1074/jbc.m112.377549] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein (apo) E4 is a major genetic risk factor for a wide spectrum of inflammatory metabolic diseases, including atherosclerosis, diabetes, and Alzheimer disease. This study compared diet-induced adipose tissue inflammation as well as functional properties of macrophages isolated from human APOE3 and APOE4 mice to identify the mechanism responsible for the association between apoE4 and inflammatory metabolic diseases. The initial study confirmed previous reports that APOE4 gene replacement mice were less sensitive than APOE3 mice to diet-induced body weight gain but exhibited hyperinsulinemia, and their adipose tissues were similarly inflamed as those in APOE3 mice. Peritoneal macrophages isolated from APOE4 mice were defective in efferocytosis compared with APOE3 macrophages. Increased cell death was also observed in APOE4 macrophages when stimulated with LPS or oxidized LDL. Western blot analysis of cell lysates revealed that APOE4 macrophages displayed elevated JNK phosphorylation indicative of cell stress even under basal culturing conditions. Significantly higher cell stress due mainly to potentiation of endoplasmic reticulum (ER) stress signaling was also observed in APOE4 macrophages after LPS and oxidized LDL activation. The defect in efferocytosis and elevated apoptosis sensitivity of APOE4 macrophages was ameliorated by treatment with the ER chaperone tauroursodeoxycholic acid. Taken together, these results showed that apoE4 expression causes macrophage dysfunction and promotes apoptosis via ER stress induction. The reduction of ER stress in macrophages may be a viable option to reduce inflammation and inflammation-related metabolic disorders associated with the apoE4 polymorphism.
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Affiliation(s)
- James G Cash
- Department of Pathology and Laboratory Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio 45237, USA
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Current world literature. Lipid metabolism. Curr Opin Lipidol 2012; 23:248-254. [PMID: 22576583 DOI: 10.1097/mol.0b013e3283543033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
PURPOSE OF REVIEW The phospholipase A2 (PLA2) family of proteins includes lipolytic enzymes that liberate the sn-2 fatty acyl chains from phospholipids to yield nonesterified fatty acids and lysophospholipids. The purpose of this review is to discuss recent findings showing distinct roles of several of these PLA2 enzymes in inflammatory metabolic diseases such as diabetes and atherosclerosis. RECENT FINDINGS The group 1B PLA2 digestion of phospholipids in the intestinal lumen facilitates postprandial lysophospholipid absorption, which suppresses hepatic fatty acid oxidation leading to increased VLDL synthesis, decreased glucose tolerance, and promotion of tissue lipid deposition to accentuate diet-induced hyperlipidemia, diabetes, and obesity. Other secretory PLA2s promote inflammatory metabolic diseases by generating bioactive lipid metabolites to induce inflammatory cytokine production, whereas the major intracellular PLA2s, cPLA2α, and iPLA2, generate arachidonic acid and lysophosphatic acid in response to extracellular stimuli to activate leukocyte chemotactic response. SUMMARY Each member of the PLA2 family of enzymes serves a distinct role in generating active lipid metabolites that promote inflammatory metabolic diseases including atherosclerosis, hyperlipidemia, obesity, and diabetes. The development of specific drugs that target one or more of these PLA2 enzymes may be novel strategies for treatment of these chronic inflammatory metabolic disorders.
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Affiliation(s)
- David Y Hui
- Department of Pathology, Metabolic Diseases Institute, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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