1
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Wilkin C, Piette J, Legrand-Poels S. Unravelling metabolic factors impacting iNKT cell biology in obesity. Biochem Pharmacol 2024:116436. [PMID: 39029630 DOI: 10.1016/j.bcp.2024.116436] [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: 04/26/2024] [Revised: 07/01/2024] [Accepted: 07/15/2024] [Indexed: 07/21/2024]
Abstract
Obesity and related diseases have reached epidemic proportions and continue to rise. Beyond creating an economical burden, obesity and its co-morbidities are associated with shortened human life expectancy. Despite major advances, the underlying mechanisms of obesity remain not fully elucidated. Recently, several studies have highlighted that various immune cells are metabolically reprogrammed in obesity, thereby profoundly affecting the immune system. This sheds light on a new field of interest: the impact of obesity-related systemic metabolic changes affecting immune system that could lead to immunosurveillance loss. Among immune cells altered by obesity, invariant Natural Killer T (iNKT) cells have recently garnered intense focus due to their ability to recognize lipid antigen. While iNKT cells are well-described to be affected by obesity, how and to what extent immunometabolic factors (e.g., lipids, glucose, cytokines, adipokines, insulin and free fatty acids) can drive iNKT cells alterations remains unclear, but represent an emerging field of research. Here, we review the current knowledge on iNKT cells in obesity and discuss the immunometabolic factors that could modulate their phenotype and activity.
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Affiliation(s)
- Chloé Wilkin
- Laboratory of Immunometabolism and Nutrition, GIGA, ULiège, Liège, Belgium.
| | - Jacques Piette
- Laboratory of Virology and Immunology, GIGA, ULiège, Liège, Belgium
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2
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Effect of aerobic exercise on GRP78 and ATF6 expressions in mice with non-alcoholic fatty liver disease. SPORTS MEDICINE AND HEALTH SCIENCE 2022. [DOI: 10.1016/j.smhs.2022.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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3
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LeBlanc G, Kreissl F, Melamed J, Sobel AL, Constantinides MG. The role of unconventional T cells in maintaining tissue homeostasis. Semin Immunol 2022; 61-64:101656. [PMID: 36306662 PMCID: PMC9828956 DOI: 10.1016/j.smim.2022.101656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 09/01/2022] [Accepted: 09/21/2022] [Indexed: 01/12/2023]
Affiliation(s)
- Gabrielle LeBlanc
- Department of Immunology & Microbiology, Scripps Research, La Jolla, CA 92037, USA,These authors contributed equally
| | - Felix Kreissl
- Department of Immunology & Microbiology, Scripps Research, La Jolla, CA 92037, USA,These authors contributed equally
| | - Jonathan Melamed
- Department of Immunology & Microbiology, Scripps Research, La Jolla, CA 92037, USA,These authors contributed equally
| | - Adam L. Sobel
- Department of Immunology & Microbiology, Scripps Research, La Jolla, CA 92037, USA,These authors contributed equally
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4
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Gu X, Chu Q, Ma X, Wang J, Chen C, Guan J, Ren Y, Wu S, Zhu H. New insights into iNKT cells and their roles in liver diseases. Front Immunol 2022; 13:1035950. [PMID: 36389715 PMCID: PMC9643775 DOI: 10.3389/fimmu.2022.1035950] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 10/14/2022] [Indexed: 08/29/2023] Open
Abstract
Natural killer T cells (NKTs) are an important part of the immune system. Since their discovery in the 1990s, researchers have gained deeper insights into the physiology and functions of these cells in many liver diseases. NKT cells are divided into two subsets, type I and type II. Type I NKT cells are also named iNKT cells as they express a semi-invariant T cell-receptor (TCR) α chain. As part of the innate immune system, hepatic iNKT cells interact with hepatocytes, macrophages (Kupffer cells), T cells, and dendritic cells through direct cell-to-cell contact and cytokine secretion, bridging the innate and adaptive immune systems. A better understanding of hepatic iNKT cells is necessary for finding new methods of treating liver disease including autoimmune liver diseases, alcoholic liver diseases (ALDs), non-alcoholic fatty liver diseases (NAFLDs), and liver tumors. Here we summarize how iNKT cells are activated, how they interact with other cells, and how they function in the presence of liver disease.
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Affiliation(s)
- Xinyu Gu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qingfei Chu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiao Ma
- Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jing Wang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Chao Chen
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jun Guan
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yanli Ren
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shanshan Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Haihong Zhu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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5
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Sozen E, Demirel-Yalciner T, Sari D, Ozer NK. Cholesterol accumulation in hepatocytes mediates IRE1/p38 branch of endoplasmic reticulum stress to promote nonalcoholic steatohepatitis. Free Radic Biol Med 2022; 191:1-7. [PMID: 35995397 DOI: 10.1016/j.freeradbiomed.2022.08.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/08/2022] [Accepted: 08/15/2022] [Indexed: 11/17/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD), based on the elevating obesity incidence, is one of the major health issue worldwide. Transition from NAFLD to non-alcoholic steatohepatitis (NASH) is driven by increased apoptosis and is relevant to higher morbidity rates. In regard to limited understanding on cholesterol mediated hepatocyte alterations in NALFD/NASH transition, we investigated endoplasmic reticulum (ER) stress and related apoptosis. Our findings suggest that cholesterol upregulates ER stress and enhances C/EBP homologous protein (CHOP) either in hypercholesterolemic rabbits or in hepatocytes treated with liposome-cholesterol complex. Mechanistically, cholesterol accumulation in hepatocytes activates IRE1/p38 branch of ER stress, stimulating CHOP levels. In liver tissues of cholesterol fed rabbits, α-tocopherol supplementation decreased IRE1/p38/CHOP activation and prevented NASH development. Thus, our study provides a critical role of hepatocyte cholesterol in inducing IRE1/p38/CHOP pathway and suggests novel candidates for therapeutic targets against NASH.
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Affiliation(s)
- Erdi Sozen
- Department of Biochemistry, Faculty of Medicine, Marmara University, Maltepe, Istanbul, 34854, Turkey; Genetic and Metabolic Diseases Research and Investigation Center (GEMHAM), Marmara University, Maltepe, Istanbul, 34854, Turkey
| | - Tugce Demirel-Yalciner
- Department of Biochemistry, Faculty of Medicine, Marmara University, Maltepe, Istanbul, 34854, Turkey
| | - Dyana Sari
- Department of Biochemistry, Faculty of Medicine, Marmara University, Maltepe, Istanbul, 34854, Turkey
| | - Nesrin Kartal Ozer
- Department of Biochemistry, Faculty of Medicine, Marmara University, Maltepe, Istanbul, 34854, Turkey.
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6
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Fiorucci S, Zampella A, Ricci P, Distrutti E, Biagioli M. Immunomodulatory functions of FXR. Mol Cell Endocrinol 2022; 551:111650. [PMID: 35472625 DOI: 10.1016/j.mce.2022.111650] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/31/2022] [Accepted: 04/04/2022] [Indexed: 02/08/2023]
Abstract
The Farnesoid-x-receptor (FXR) is a bile acids sensor activated in humans by primary bile acids. FXR is mostly expressed in liver, intestine and adrenal glands but also by cells of innate immunity, including macrophages, liver resident macrophages, the Kupffer cells, natural killer cells and dendritic cells. In normal physiology and clinical disorders, cells of innate immunity mediate communications between liver, intestine and adipose tissues. In addition to FXR, the G protein coupled receptor (GPBAR1), that is mainly activated by secondary bile acids, whose expression largely overlaps FXR, modulates chemical communications from the intestinal microbiota and the host's immune system, integrating epithelial cells and immune cells in the entero-hepatic system, providing a mechanism for development of a tolerogenic state toward the intestinal microbiota. Disruption of FXR results in generalized inflammation and disrupted bile acids metabolism. While FXR agonism in preclinical models provides counter-regulatory signals that attenuate inflammation-driven immune dysfunction in a variety of liver and intestinal disease models, the clinical relevance of these mechanisms in the setting of FXR-related disorders remain poorly defined.
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Affiliation(s)
- Stefano Fiorucci
- Dipartimento di Medicina e Chirurgia, Università di Perugia, Perugia, Italy. http://www.gastroenterologia.unipg.it
| | - Angela Zampella
- University of Naples Federico II, Department of Pharmacy, Naples, Italy
| | - Patrizia Ricci
- Dipartimento di Medicina e Chirurgia, Università di Perugia, Perugia, Italy
| | - Eleonora Distrutti
- SC di Gastroenterologia ed Epatologia, Azienda Ospedaliera di Perugia, Perugia, Italy
| | - Michele Biagioli
- Dipartimento di Medicina e Chirurgia, Università di Perugia, Perugia, Italy
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7
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Alharbi S. Exogenous administration of unacylated ghrelin attenuates hepatic steatosis in high-fat diet-fed rats by modulating glucose homeostasis, lipogenesis, oxidative stress, and endoplasmic reticulum stress. Biomed Pharmacother 2022; 151:113095. [PMID: 35594708 DOI: 10.1016/j.biopha.2022.113095] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/01/2022] [Accepted: 05/04/2022] [Indexed: 11/25/2022] Open
Abstract
Low levels of unacylated ghrelin (UAG) and a higher ratio of acylated ghrelin (AG)/UAG in obesity are associated with non-alcoholic fatty liver disease (NAFLD). This study tested the potential protective effect of increased circulatory levels of UAG by exogenous UAG administration on hepatic steatosis in high-fat diet (HFD)-fed rats and investigated some possible mechanisms. Rats were divided (n = 6/group) as low fat diet (LFD), LFD + UAG (200 mg/kg), HFD, HFD + UAG (50, 100, or 200 mg/kg). Treatments were given for 8 weeks. Increasing the dose of UAG increased circulatory levels of UAG and normalized the ratio of AG/UAG at the dose of 200 mg/kg. With no change in insulin levels, and in a dose-dependent manner, treatment with UAG to HFD rats attenuated the gain in food intake, body weights, and liver weights, lowered fasting glucose levels, prevented hepatic cytoplasmic vacuolization, and reduced serum and hepatic levels of cholesterol, triglycerides, and free fatty acids. They also progressively reduced levels of reactive oxygen species, lipid peroxides, tumor necrosis factor-α, and interleukin-6, as well as mRNA levels of Bax and caspase-3 but increased levels of glutathione and superoxide dismutase and mRNA levels of Bcl2. In concomitant, UAG, in a dose-response manner, significantly reduced hepatic mRNA levels of SREBP1, SREBP2, ATF-6, IRE-1, and eIF-2α but increased those of PPARα. In conclusion, reducing the circulatory ratio of AG/UAG ratio by exogenous administration of UAG attenuates HFD-induced hepatic steatosis by suppressing lipogenesis, stimulating FAs oxidation, preventing oxidative stress, inflammation, ER stress, and apoptosis.
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Affiliation(s)
- Samah Alharbi
- Physiology Department, Faculty of Medicine, Umm Al-Qura University, Makkah, Saudi Arabia.
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8
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Abstract
Blood vessel endothelial cells (ECs) have long been known to modulate inflammation by regulating immune cell trafficking, activation status and function. However, whether the heterogeneous EC populations in various tissues and organs differ in their immunomodulatory capacity has received insufficient attention, certainly with regard to considering them for alternative immunotherapy. Recent single-cell studies have identified specific EC subtypes that express gene signatures indicative of phagocytosis or scavenging, antigen presentation and immune cell recruitment. Here we discuss emerging evidence suggesting a tissue-specific and vessel type-specific immunomodulatory role for distinct subtypes of ECs, here collectively referred to as 'immunomodulatory ECs' (IMECs). We propose that IMECs have more important functions in immunity than previously recognized, and suggest that these might be considered as targets for new immunotherapeutic approaches.
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9
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Bile acid activated receptors: Integrating immune and metabolic regulation in non-alcoholic fatty liver disease. LIVER RESEARCH 2021. [DOI: 10.1016/j.livres.2021.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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10
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Chen Y, Tian Z. Roles of Hepatic Innate and Innate-Like Lymphocytes in Nonalcoholic Steatohepatitis. Front Immunol 2020; 11:1500. [PMID: 32765518 PMCID: PMC7378363 DOI: 10.3389/fimmu.2020.01500] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/09/2020] [Indexed: 12/14/2022] Open
Abstract
Nonalcoholic steatohepatitis (NASH), a progressive form of nonalcoholic fatty liver disease (NAFLD), is accompanied by steatosis, hepatocyte injury and liver inflammation, which has been a health problem in the world as one of the major high risk factors of cirrhosis and hepatocellular carcinoma (HCC). Complex immune responses involving T cells, B cells, Kupffer cells, monocytes, neutrophils, DCs and other innate lymphocytes account for the pathogenesis of NASH; however, the underlying mechanisms have not been clearly elucidated in detail. In the liver, innate and innate-like lymphocytes account for more than two-thirds of total lymphocytes and play an important role in maintaining the immune homeostasis. Therefore, their roles in the progression of NASH deserves investigation. In this review, we summarized murine NASH models for immunological studies, including the diet-induced NASH, chemical-induced NASH and genetic-induced NASH. The role of innate and innate-like lymphocytes including NK cells, ILCs, NKT, γδT and MAIT cells in the progression of NASH were elucidated. Further, the metabolic regulation of the innate immune response was addressed in consideration to explain the molecular mechanisms. Based on the findings of the reviewed studies, strategies of immune intervention are proposed to control the progression of NASH.
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Affiliation(s)
- Yongyan Chen
- Hefei National Laboratory for Physical Sciences at Microscale, The CAS Key Laboratory of Innate Immunity and Chronic Disease, Division of Molecular Medicine, School of Life Sciences, University of Science and Technology of China, Hefei, China.,Institute of Immunology, University of Science and Technology of China, Hefei, China
| | - Zhigang Tian
- Hefei National Laboratory for Physical Sciences at Microscale, The CAS Key Laboratory of Innate Immunity and Chronic Disease, Division of Molecular Medicine, School of Life Sciences, University of Science and Technology of China, Hefei, China.,Institute of Immunology, University of Science and Technology of China, Hefei, China
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11
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Vallée D, Blanc M, Lebeaupin C, Bailly-Maitre B. [Endoplasmic reticulum stress response and pathogenesis of non-alcoholic steatohepatitis]. Med Sci (Paris) 2020; 36:119-129. [PMID: 32129747 DOI: 10.1051/medsci/2020008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The incidence of chronic liver disease is constantly increasing, owing to the obesity epidemic. Non-alcoholic fatty liver disease (NAFLD) is currently affecting 20-30% of the general population and 75-100% of obese individuals. NAFLD ranges from simple steatosis to damaging non-alcoholic steatohepatitis (NASH), potentially developing into hepatocellular carcinoma. No efficient pharmacological treatment is yet available. During obesity, the hepatic ER stress response can arise from extracellular stress (lipids, glucose, cytokines) and from intracellular stress including lipid buildup in the hepatocyte (steatosis), a hallmark of NAFLD. The chronic activation of the hepatic ER stress response may be a crucial event in the steatosis-NASH transition, triggering cell death, inflammation and accelerating metabolic disorders. We discuss these aspects and we propose that targeting the ER stress response could be effective in treating NAFLD.
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Affiliation(s)
- Déborah Vallée
- Centre méditerranéen de médecine moléculaire (C3M), Inserm U1065, 151, Route de St Antoine de Ginestière, 06204 Nice, France
| | - Marina Blanc
- Centre méditerranéen de médecine moléculaire (C3M), Inserm U1065, 151, Route de St Antoine de Ginestière, 06204 Nice, France
| | - Cynthia Lebeaupin
- Centre méditerranéen de médecine moléculaire (C3M), Inserm U1065, 151, Route de St Antoine de Ginestière, 06204 Nice, France
| | - Béatrice Bailly-Maitre
- Centre méditerranéen de médecine moléculaire (C3M), Inserm U1065, 151, Route de St Antoine de Ginestière, 06204 Nice, France
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12
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Feng D. The alteration of immune cells in the pathogenesis of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis. LIVER RESEARCH 2020. [DOI: 10.1016/j.livres.2020.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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13
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Riffelmacher T, Kronenberg M. Metabolic Triggers of Invariant Natural Killer T-Cell Activation during Sterile Autoinflammatory Disease. Crit Rev Immunol 2020; 40:367-378. [PMID: 33463949 PMCID: PMC7116673 DOI: 10.1615/critrevimmunol.2020035158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ample evidence exists for activation of invariant natural killer T (iNKT) cells in a sterile manner by endogenous ligands or microbial antigens from the commensal flora, indicating that iNKT cells are not truly self-tolerant. Their controlled autoreactivity state is disturbed in many types of sterile inflammatory disease, resulting in their central role in modulating autoimmune responses. This review focuses on sterile iNKT-cell responses that are initiated by metabolic triggers, such as obesity-associated inflammation and fatty liver disease, as a manifestation of metabolic disease and dyslipidemia, as well as ischemia reperfusion injuries and sickle cell disease, characterized by acute lack of oxygen and oxidative stress response on reperfusion. In the intestine, inflammation and iNKT-cell response type are shaped by the microbiome as an extended "self". Disease- and organ-specific differences in iNKT-cell response type are summarized and help to define common pathways that shape iNKT-cell responses in the absence of exogenous antigen.
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Affiliation(s)
- Thomas Riffelmacher
- La Jolla Institute for Immunology, La Jolla, CA 92037
- Kennedy Institute of Rheumatology, University of Oxford, Roosevelt Drive, Oxford OX3 7FY, UK
| | - Mitchell Kronenberg
- La Jolla Institute for Immunology, La Jolla, CA 92037
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093
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14
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Key features and homing properties of NK cells in the liver are shaped by activated iNKT cells. Sci Rep 2019; 9:16362. [PMID: 31704965 PMCID: PMC6841958 DOI: 10.1038/s41598-019-52666-9] [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: 01/10/2017] [Accepted: 10/16/2019] [Indexed: 11/16/2022] Open
Abstract
The contribution of natural killer (NK) cells to the clearance of hepatic viral infections is well recognized. The recently discovered heterogeneity of NK cell populations renders them interesting targets for immune interventions. Invariant natural killer T (iNKT) cells represent a key interaction partner for hepatic NK cells. The present study addressed whether characteristics of NK cells in the liver can be shaped by targeting iNKT cells. For this, the CD1d-binding pegylated glycolipid αGalCerMPEG was assessed for its ability to modulate the features of NK cells permanently or transiently residing in the liver. In vivo administration resulted in enhanced functionality of educated and highly differentiated CD27+ Mac-1+ NK cells accompanied by an increased proliferation. Improved liver homing was supported by serum-derived and cellular factors. Reduced viral loads in a mCMV infection model confirmed the beneficial effect of NK cells located in the liver upon stimulation with αGalCerMPEG. Thus, targeting iNKT cell-mediated NK cell activation in the liver represents a promising approach for the establishment of liver-directed immune interventions.
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15
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Chen D, Gao X, Wang J, Zhao H, Liu H, Chen S, Zhang J, Meng M. Activation of hepatic iNKT2 cells by α-GalCer ameliorates hepatic steatosis induced by high-fat diet in C57BL/6J mice. Int Immunopharmacol 2019; 74:105727. [PMID: 31284229 DOI: 10.1016/j.intimp.2019.105727] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/25/2019] [Accepted: 06/26/2019] [Indexed: 12/12/2022]
Abstract
The existence of association between the subpopulation of iNKT cells with different functions and nonalcoholic fatty liver disease has not been confirmed. To investigative the role of iNKT cells in the pathogenesis of nonalcoholic fatty liver disease, we established a non-alcoholic fatty liver model by feeding C57BL/6J mice for 12 weeks with a high-fat diet and injecting α-GalCer through different routes to activate hepatic iNKT cells. The liver of the mice fed a high-fat diet (HFD) had severe hepatic steatosis appearance, elevated pro-inflammatory cytokines and reduced anti-inflammatory cytokines in the liver, and high serum levels of TC, LDL, HDL, and ALT. Our results showed that the percentage of iNKT cells in the liver of the HFD-fed mice was lower than that of the control mice. The expression levels of the related transcription factor of T-bet increased but that of GATA-3 decreased in the HFD-fed mice. The administration of α-GalCer by intraperitoneal injection resulted in increasing of hepatic iNKT and iNKT2 cells but decreasing of hepatic iNKT1 cells, and the expression of GATA-3 and anti-inflammatory cytokine (IL-4) was increased in the liver, and hepatic steatosis was ameliorated in the HFD-fed mice. The administration of α-GalCer by subcutaneous injection resulted in a decrease in hepatic iNKT and iNKT2 and an augmentation of hepatic iNKT1 cells. However, hepatic steatosis was not significantly improved. We concluded that the intraperitoneal injection with α-GalCer effectively improved hepatic steatosis, according to increasing the number of hepatic iNKT2 cells. The precise mechanism requires further exploration.
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Affiliation(s)
- Dongzhi Chen
- Key Laboratory of Pathogenesis Mechanism and Control of Inflammatory-autoimmune Diseases in Hebei Province, Baoding, PR China; Department of Immunology, School of Medicine, Hebei University, Baoding, 071000, Hebei Province, PR China
| | - Xiang Gao
- Key Laboratory of Pathogenesis Mechanism and Control of Inflammatory-autoimmune Diseases in Hebei Province, Baoding, PR China; Department of Immunology, School of Medicine, Hebei University, Baoding, 071000, Hebei Province, PR China
| | - Jianguo Wang
- Affiliated Hospital of Hebei University, Baoding, 071000, Hebei Province, PR China
| | - Huijuan Zhao
- Key Laboratory of Pathogenesis Mechanism and Control of Inflammatory-autoimmune Diseases in Hebei Province, Baoding, PR China; Department of Immunology, School of Medicine, Hebei University, Baoding, 071000, Hebei Province, PR China
| | - Huifang Liu
- Key Laboratory of Pathogenesis Mechanism and Control of Inflammatory-autoimmune Diseases in Hebei Province, Baoding, PR China; Department of Immunology, School of Medicine, Hebei University, Baoding, 071000, Hebei Province, PR China
| | - Shengde Chen
- Key Laboratory of Pathogenesis Mechanism and Control of Inflammatory-autoimmune Diseases in Hebei Province, Baoding, PR China; Department of Immunology, School of Medicine, Hebei University, Baoding, 071000, Hebei Province, PR China
| | - Jingnan Zhang
- Key Laboratory of Pathogenesis Mechanism and Control of Inflammatory-autoimmune Diseases in Hebei Province, Baoding, PR China; Department of Immunology, School of Medicine, Hebei University, Baoding, 071000, Hebei Province, PR China
| | - Ming Meng
- Key Laboratory of Pathogenesis Mechanism and Control of Inflammatory-autoimmune Diseases in Hebei Province, Baoding, PR China; Department of Immunology, School of Medicine, Hebei University, Baoding, 071000, Hebei Province, PR China.
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16
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Van Herck MA, Weyler J, Kwanten WJ, Dirinck EL, De Winter BY, Francque SM, Vonghia L. The Differential Roles of T Cells in Non-alcoholic Fatty Liver Disease and Obesity. Front Immunol 2019; 10:82. [PMID: 30787925 PMCID: PMC6372559 DOI: 10.3389/fimmu.2019.00082] [Citation(s) in RCA: 155] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 01/11/2019] [Indexed: 12/15/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) constitutes a spectrum of disease states characterized by hepatic steatosis and is closely associated to obesity and the metabolic syndrome. In non-alcoholic steatohepatitis (NASH), additionally, inflammatory changes and hepatocellular damage are present, representing a more severe condition, for which the treatment is an unmet medical need. Pathophysiologically, the immune system is one of the main drivers of NAFLD progression and other obesity-related comorbidities, and both the innate and adaptive immune system are involved. T cells form the cellular component of the adaptive immune system and consist of multiple differentially active subsets, i.e., T helper (Th) cells, regulatory T (Treg) cells, and cytotoxic T (Tc) cells, as well as several innate T-cell subsets. This review focuses on the role of these T-cell subsets in the pathogenesis of NAFLD, as well as the association with obesity and type 2 diabetes mellitus, reviewing the available evidence from both animal and human studies. Briefly, Th1, Th2, Th17, and Th22 cells seem to have an attenuating effect on adiposity. Th2, Th22, and Treg cells seem to decrease insulin resistance, whereas Th1, Th17, and Tc cells have an aggravating effect. Concerning NAFLD, both Th22 and Treg cells appear to have an overall tempering effect, whereas Th17 and Tc cells seem to induce more liver damage and fibrosis progression. The evidence regarding the role of the innate T-cell subsets is more controversial and warrants further exploration.
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Affiliation(s)
- Mikhaïl A Van Herck
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology and Hepatology, University of Antwerp, Antwerp, Belgium.,Department of Gastroenterology and Hepatology, Antwerp University Hospital, Antwerp, Belgium
| | - Jonas Weyler
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology and Hepatology, University of Antwerp, Antwerp, Belgium.,Department of Gastroenterology and Hepatology, Antwerp University Hospital, Antwerp, Belgium
| | - Wilhelmus J Kwanten
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology and Hepatology, University of Antwerp, Antwerp, Belgium.,Department of Gastroenterology and Hepatology, Antwerp University Hospital, Antwerp, Belgium
| | - Eveline L Dirinck
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology and Hepatology, University of Antwerp, Antwerp, Belgium.,Department of Endocrinology, Diabetology and Metabolism, Antwerp University Hospital, Antwerp, Belgium
| | - Benedicte Y De Winter
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology and Hepatology, University of Antwerp, Antwerp, Belgium
| | - Sven M Francque
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology and Hepatology, University of Antwerp, Antwerp, Belgium.,Department of Gastroenterology and Hepatology, Antwerp University Hospital, Antwerp, Belgium
| | - Luisa Vonghia
- Laboratory of Experimental Medicine and Pediatrics, Division of Gastroenterology and Hepatology, University of Antwerp, Antwerp, Belgium.,Department of Gastroenterology and Hepatology, Antwerp University Hospital, Antwerp, Belgium
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17
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Ore A, Akinloye OA. Oxidative Stress and Antioxidant Biomarkers in Clinical and Experimental Models of Non-Alcoholic Fatty Liver Disease. ACTA ACUST UNITED AC 2019; 55:medicina55020026. [PMID: 30682878 PMCID: PMC6410206 DOI: 10.3390/medicina55020026] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 01/18/2019] [Indexed: 02/07/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a term that covers a range of hepatic disorders involving fat deposits in the liver. NAFLD begins with simple steatosis and progresses into non-alcoholic steatohepatitis (NASH) characterised by inflammation, fibrosis, apoptosis, oxidative stress, lipid peroxidation, mitochondrial dysfunction and release of adipokines and pro-inflammatory cytokines. Oxidative stress and antioxidants are known to play a vital role in the pathogenesis and severity of NAFLD/NASH. A number of oxidative stress and antioxidant markers are employed in the assessment of the pathological state and progression of the disease. In this article, we review several biomarkers of oxidative stress and antioxidants that have been measured at clinical and experimental levels. Also included is a comprehensive description of oxidative stress, sources and contribution to the pathogenesis of NAFLD/NASH.
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Affiliation(s)
- Ayokanmi Ore
- Department of Biochemistry, College of Biosciences, Federal University of Agriculture, Abeokuta, Nigeria.
- Biochemistry Division, Department of Chemical Sciences, Faculty of Natural Sciences, Ajayi Crowther University, Oyo, Nigeria.
| | - Oluseyi Adeboye Akinloye
- Department of Biochemistry, College of Biosciences, Federal University of Agriculture, Abeokuta, Nigeria.
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18
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Tan X, Ding Y, Zhu P, Dou R, Liang Z, Yang D, Huang Z, Wang W, Wu X, Weng X. Elevated Hepatic CD1d Levels Coincide with Invariant NKT Cell Defects in Chronic Hepatitis B Virus Infection. THE JOURNAL OF IMMUNOLOGY 2018; 200:3530-3538. [DOI: 10.4049/jimmunol.1701801] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 03/15/2018] [Indexed: 12/23/2022]
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19
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20
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CD1d-Restricted pathways in hepatocytes control local natural killer T cell homeostasis and hepatic inflammation. Proc Natl Acad Sci U S A 2017; 114:10449-10454. [PMID: 28893990 DOI: 10.1073/pnas.1701428114] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Invariant natural killer T (iNKT) cells recognize lipid antigens presented by CD1d and play a central role in regulating immunity and inflammation in peripheral tissues. However, the mechanisms which govern iNKT cell homeostasis after thymic emigration are incompletely understood. Here we demonstrate that microsomal triglyceride transfer protein (MTP), a protein involved in the transfer of lipids onto CD1d, regulates liver iNKT cell homeostasis in a manner dependent on hepatocyte CD1d. Mice with hepatocyte-specific loss of MTP exhibit defects in the function of CD1d and show increased hepatic iNKT cell numbers as a consequence of altered iNKT cell apoptosis. Similar findings were made in mice with hepatocyte-specific loss of CD1d, confirming a critical role of CD1d in this process. Moreover, increased hepatic iNKT cell abundance in the absence of MTP is associated with susceptibility to severe iNKT cell-mediated hepatitis, thus demonstrating the importance of CD1d-dependent control of liver iNKT cells in maintaining immunological homeostasis in the liver. Together, these data demonstrate an unanticipated role of parenchymal cells, as shown here for hepatocytes, in tissue-specific regulation of CD1d-restricted immunity and further suggest that alterations in lipid metabolism may affect iNKT cell homeostasis through effects on CD1d-associated lipid antigens.
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21
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Harada N, Okuyama M, Yoshikatsu A, Yamamoto H, Ishiwata S, Hamada C, Hirose T, Shono M, Kuroda M, Tsutsumi R, Takeo J, Taketani Y, Nakaya Y, Sakaue H. Endoplasmic Reticulum Stress in Mice Increases Hepatic Expression of Genes Carrying a Premature Termination Codon via a Nutritional Status‐Independent GRP78‐Dependent Mechanism. J Cell Biochem 2017; 118:3810-3824. [DOI: 10.1002/jcb.26031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 04/04/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Nagakatsu Harada
- Department of Nutrition and MetabolismInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
| | - Maiko Okuyama
- Department of Nutrition and MetabolismInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
| | - Aya Yoshikatsu
- Department of Nutrition and MetabolismInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
| | - Hironori Yamamoto
- Faculty of Human LifeDepartment of Health and NutritionJin‐ai University3‐1‐1 Ohde‐choEchizen City915‐8586Japan
| | - Saori Ishiwata
- Department of Nutrition and MetabolismInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
| | - Chikako Hamada
- Department of Nutrition and MetabolismInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
| | - Tomoyo Hirose
- Department of Nutrition and MetabolismInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
| | - Masayuki Shono
- Support Center for Advanced Medical SciencesInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
| | - Masashi Kuroda
- Department of Nutrition and MetabolismInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
| | - Rie Tsutsumi
- Department of Nutrition and MetabolismInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
| | - Jiro Takeo
- Department of Nutrition and MetabolismInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
- Central Research LaboratoryNippon Suisan Kaisha32‐3 Nanakuni 1 ChomeHachiojiTokyo192‐0991Japan
| | - Yutaka Taketani
- Department of Clinical Nutrition and Food ManagementInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
| | - Yutaka Nakaya
- Department of Nutrition and MetabolismInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
| | - Hiroshi Sakaue
- Department of Nutrition and MetabolismInstitute of Biomedical SciencesTokushima University Graduate School3‐18‐15, Kuramoto‐choTokushima City770‐8503Japan
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22
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Li F, Hao X, Chen Y, Bai L, Gao X, Lian Z, Wei H, Sun R, Tian Z. The microbiota maintain homeostasis of liver-resident γδT-17 cells in a lipid antigen/CD1d-dependent manner. Nat Commun 2017; 7:13839. [PMID: 28067223 PMCID: PMC5227332 DOI: 10.1038/ncomms13839] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 11/04/2016] [Indexed: 02/08/2023] Open
Abstract
The microbiota control regional immunity using mechanisms such as inducing IL-17A-producing γδ T (γδT-17) cells in various tissues. However, little is known regarding hepatic γδT cells that are constantly stimulated by gut commensal microbes. Here we show hepatic γδT cells are liver-resident cells and predominant producers of IL-17A. The microbiota sustain hepatic γδT-17 cell homeostasis, including activation, survival and proliferation. The global commensal quantity affects the number of liver-resident γδT-17 cells; indeed, E. coli alone can generate γδT-17 cells in a dose-dependent manner. Liver-resident γδT-17 cell homeostasis depends on hepatocyte-expressed CD1d, that present lipid antigen, but not Toll-like receptors or IL-1/IL-23 receptor signalling. Supplementing mice in vivo or loading hepatocytes in vitro with exogenous commensal lipid antigens augments the hepatic γδT-17 cell number. Moreover, the microbiota accelerate nonalcoholic fatty liver disease through hepatic γδT-17 cells. Thus, our work describes a unique liver-resident γδT-17 cell subset maintained by gut commensal microbes through CD1d/lipid antigens. γδ T cells are major producers of IL-17A in response to microbial infection. Here the authors show that a high load of commensal microbes can maintain homeostasis of IL-17A+ γδ T cells in the liver via CD1d antigen presentation, with implications for liver diseases.
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Affiliation(s)
- Fenglei Li
- Institute of Immunology and the Key Laboratory of Innate Immunity and Chronic Disease (Chinese Academy of Science), School of Life Science and Medical Center, University of Science and Technology of China, Hefei 230027, China
| | - Xiaolei Hao
- Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China
| | - Yongyan Chen
- Institute of Immunology and the Key Laboratory of Innate Immunity and Chronic Disease (Chinese Academy of Science), School of Life Science and Medical Center, University of Science and Technology of China, Hefei 230027, China
| | - Li Bai
- Institute of Immunology and the Key Laboratory of Innate Immunity and Chronic Disease (Chinese Academy of Science), School of Life Science and Medical Center, University of Science and Technology of China, Hefei 230027, China
| | - Xiang Gao
- Model Animal Research Center, Nanjing University, Nanjing, Jiangsu 210061, China
| | - Zhexiong Lian
- Institute of Immunology and the Key Laboratory of Innate Immunity and Chronic Disease (Chinese Academy of Science), School of Life Science and Medical Center, University of Science and Technology of China, Hefei 230027, China
| | - Haiming Wei
- Institute of Immunology and the Key Laboratory of Innate Immunity and Chronic Disease (Chinese Academy of Science), School of Life Science and Medical Center, University of Science and Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China
| | - Rui Sun
- Institute of Immunology and the Key Laboratory of Innate Immunity and Chronic Disease (Chinese Academy of Science), School of Life Science and Medical Center, University of Science and Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, China
| | - Zhigang Tian
- Institute of Immunology and the Key Laboratory of Innate Immunity and Chronic Disease (Chinese Academy of Science), School of Life Science and Medical Center, University of Science and Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230027, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, China
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Henkel AS, LeCuyer B, Olivares S, Green RM. Endoplasmic Reticulum Stress Regulates Hepatic Bile Acid Metabolism in Mice. Cell Mol Gastroenterol Hepatol 2016; 3:261-271. [PMID: 28275692 PMCID: PMC5331781 DOI: 10.1016/j.jcmgh.2016.11.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 11/01/2016] [Indexed: 12/31/2022]
Abstract
BACKGROUND & AIMS Cholestasis promotes endoplasmic reticulum (ER) stress in the liver, however, the effect of ER stress on hepatic bile acid metabolism is unknown. We aim to determine the effect of ER stress on hepatic bile acid synthesis and transport in mice. METHODS ER stress was induced pharmacologically in C57BL/6J mice and human hepatoma (HepG2) cells. The hepatic expression of genes controlling bile acid synthesis and transport was determined. To measure the activity of the primary bile acid synthetic pathway, the concentration of 7α-hydroxy-4-cholesten-3-1 was measured in plasma. RESULTS Induction of ER stress in mice and HepG2 cells rapidly suppressed the hepatic expression of the primary bile acid synthetic enzyme, cholesterol 7α-hydroxylase. Plasma levels of 7α-hydroxy-4-cholesten-3-1 were reduced in mice subjected to ER stress, indicating impaired bile acid synthesis. Induction of ER stress in mice and HepG2 cells increased expression of the bile salt export pump (adenosine triphosphate binding cassette [Abc]b11) and a bile salt efflux pump (Abcc3). The observed regulation of Cyp7a1, Abcb11, and Abcc3 occurred in the absence of hepatic inflammatory cytokine activation and was not dependent on activation of hepatic small heterodimer partner or intestinal fibroblast growth factor 15. Consistent with suppressed bile acid synthesis and enhanced bile acid export from hepatocytes, prolonged ER stress decreased the hepatic bile acid content in mice. CONCLUSIONS Induction of ER stress in mice suppresses bile acid synthesis and enhances bile acid removal from hepatocytes independently of established bile acid regulatory pathways. These data show a novel function of the ER stress response in regulating bile acid metabolism.
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Key Words
- 7α-Hydroxy-4-Cholesten-3-1
- ABC, adenosine triphosphate binding cassette
- Bile Acid Synthesis
- C4, 7α-hydroxy-4-cholesten-3-1
- CYP7A1, cholesterol 7α-hydroxylase
- Cyp7a1
- DMEM, Dulbecco's modified Eagle medium
- DMSO, dimethyl sulfoxide
- ER, endoplasmic reticulum
- ERK, extracellular signaling-regulated kinase
- FGF, fibroblast growth factor
- FXR, farnesoid X receptor
- IL, interleukin
- IRE1α, inositol requiring enzyme 1α
- JNK, c-Jun-N-terminal kinase
- NTCP, sodium/taurocholate cotransporter
- RIDD, regulated inositol requiring enzyme 1α–dependent messenger RNA decay
- SHP, small heterodimer partner
- UPR, unfolded protein response
- Unfolded Protein Response
- mRNA, messenger RNA
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Affiliation(s)
- Anne S. Henkel
- Correspondence Address correspondence to: Anne S. Henkel, MD, 320 East Superior Street, Tarry 15-705, Chicago, Illinois 60611. fax: (312) 908-9032.320 East Superior StreetTarry 15-705ChicagoIllinois 60611
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24
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Pozzo L, Vornoli A, Coppola I, Croce CMD, Giorgetti L, Gervasi PG, Longo V. Effect of HFD/STZ on expression of genes involved in lipid, cholesterol and glucose metabolism in rats. Life Sci 2016; 166:149-156. [DOI: 10.1016/j.lfs.2016.09.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 09/13/2016] [Accepted: 09/26/2016] [Indexed: 12/12/2022]
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25
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Dasgupta S, Kumar V. Type II NKT cells: a distinct CD1d-restricted immune regulatory NKT cell subset. Immunogenetics 2016; 68:665-76. [PMID: 27405300 PMCID: PMC6334657 DOI: 10.1007/s00251-016-0930-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 06/22/2016] [Indexed: 12/16/2022]
Abstract
Type II natural killer T cells (NKT) are a subset of the innate-like CD1d-restricted lymphocytes that are reactive to lipid antigens. Unlike the type I NKT cells, which express a semi-invariant TCR, type II NKT cells express a broader TCR repertoire. Additionally, other features, such as their predominance over type I cells in humans versus mice, the nature of their ligands, CD1d/lipid/TCR binding, and modulation of immune responses, distinguish type II NKT cells from type I NKT cells. Interestingly, it is the self-lipid-reactivity of type II NKT cells that has helped define their physiological role in health and in disease. The discovery of sulfatide as one of the major antigens for CD1d-restricted type II NKT cells in mice has been instrumental in the characterization of these cells, including the TCR repertoire, the crystal structure of the CD1d/lipid/TCR complex, and their function. Subsequently, several other glycolipids and phospholipids from both endogenous and microbial sources have been shown to activate type II NKT cells. The activation of a specific subset of type II NKT cells following administration with sulfatide or lysophosphatidylcholine (LPC) leads to engagement of a dominant immunoregulatory pathway associated with the inactivation of type I NKT cells, conventional dendritic cells, and inhibition of the proinflammatory Th1/Th17 cells. Thus, type II NKT cells have been shown to be immunosuppressive in autoimmune diseases, inflammatory liver diseases, and in cancer. Knowing their relatively higher prevalence in human than type I NKT cells, understanding their biology is imperative for health and disease.
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Affiliation(s)
- Suryasarathi Dasgupta
- Division of Gastroenterology, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92037, USA
| | - Vipin Kumar
- Division of Gastroenterology, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92037, USA.
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26
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Fahrner R, Dondorf F, Ardelt M, Settmacher U, Rauchfuss F. Role of NK, NKT cells and macrophages in liver transplantation. World J Gastroenterol 2016; 22:6135-6144. [PMID: 27468206 PMCID: PMC4945975 DOI: 10.3748/wjg.v22.i27.6135] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/25/2016] [Accepted: 06/15/2016] [Indexed: 02/07/2023] Open
Abstract
Liver transplantation has become the treatment of choice for acute or chronic liver disease. Because the liver acts as an innate immunity-dominant organ, there are immunological differences between the liver and other organs. The specific features of hepatic natural killer (NK), NKT and Kupffer cells and their role in the mechanism of liver transplant rejection, tolerance and hepatic ischemia-reperfusion injury are discussed in this review.
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27
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Robinson MW, Harmon C, O'Farrelly C. Liver immunology and its role in inflammation and homeostasis. Cell Mol Immunol 2016; 13:267-76. [PMID: 27063467 PMCID: PMC4856809 DOI: 10.1038/cmi.2016.3] [Citation(s) in RCA: 646] [Impact Index Per Article: 80.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 01/08/2016] [Accepted: 01/09/2016] [Indexed: 12/12/2022] Open
Abstract
The human liver is usually perceived as a non-immunological organ engaged primarily in metabolic, nutrient storage and detoxification activities. However, we now know that the healthy liver is also a site of complex immunological activity mediated by a diverse immune cell repertoire as well as non-hematopoietic cell populations. In the non-diseased liver, metabolic and tissue remodeling functions require elements of inflammation. This inflammation, in combination with regular exposure to dietary and microbial products, creates the potential for excessive immune activation. In this complex microenvironment, the hepatic immune system tolerates harmless molecules while at the same time remaining alert to possible infectious agents, malignant cells or tissue damage. Upon appropriate immune activation to challenge by pathogens or tissue damage, mechanisms to resolve inflammation are essential to maintain liver homeostasis. Failure to clear 'dangerous' stimuli or regulate appropriately activated immune mechanisms leads to pathological inflammation and disrupted tissue homeostasis characterized by the progressive development of fibrosis, cirrhosis and eventual liver failure. Hepatic inflammatory mechanisms therefore have a spectrum of roles in the healthy adult liver; they are essential to maintain tissue and organ homeostasis and, when dysregulated, are key drivers of the liver pathology associated with chronic infection, autoimmunity and malignancy. In this review, we explore the changing perception of inflammation and inflammatory mediators in normal liver homeostasis and propose targeting of liver-specific immune regulation pathways as a therapeutic approach to treat liver disease.
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Affiliation(s)
- Mark W Robinson
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin D2, Ireland
| | - Cathal Harmon
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin D2, Ireland
| | - Cliona O'Farrelly
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin D2, Ireland
- School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin D2, Ireland
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28
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Ashraf NU, Sheikh TA. Endoplasmic reticulum stress and Oxidative stress in the pathogenesis of Non-alcoholic fatty liver disease. Free Radic Res 2015. [PMID: 26223319 DOI: 10.3109/10715762.2015.1078461] [Citation(s) in RCA: 208] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome. The underlying causes of the disease progression in NAFLD are unclear. Recent evidences suggest endoplasmic reticulum stress in the development of lipid droplets (steatosis) and subsequent generation of reactive oxygen species (ROS) in the progression to non-alcoholic steatohepatitis (NASH). The signalling pathway activated by disruption of endoplasmic reticulum (ER) homoeostasis, called as unfolded protein response, is linked with membrane biosynthesis, insulin action, inflammation and apoptosis. ROS are important mediators of inflammation. Protein folding in ER is linked to ROS. Therefore understanding the basic mechanisms that lead to ER stress and ROS in NAFLD have become the topics of immense interest. The present review focuses on the role of ER stress and ROS in the pathogenesis of NAFLD. We also highlight the cross talk between ER stress and oxidative stress which suggest and encourage the development of therapeutics for NAFLD. Further we have reviewed various strategies used for the management of NAFLD/NASH and limitations of such strategies. Our review therefore highlights the need for newer strategies with regards to ER stress and oxidative stress.
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Affiliation(s)
- N U Ashraf
- a Academy of Scientific and Innovative Research (AcSIR) , New Delhi , India.,b PK-PD and Toxicology Division, CSIR-Indian Institute of Integrative Medicine , Canal Road, Jammu Tawi , Jammu and Kashmir , India
| | - T A Sheikh
- a Academy of Scientific and Innovative Research (AcSIR) , New Delhi , India.,b PK-PD and Toxicology Division, CSIR-Indian Institute of Integrative Medicine , Canal Road, Jammu Tawi , Jammu and Kashmir , India
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29
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Abstract
Invariant natural killer T (iNKT) cells are a unique population of T lymphocytes, which lie at the interface between the innate and adaptive immune systems, and are important mediators of immune responses and tumor surveillance. iNKT cells recognize lipid antigens in a CD1d-dependent manner; their subsequent activation results in a rapid and specific downstream response, which enhances both innate and adaptive immunity. The capacity of iNKT cells to modify the immune microenvironment influences the ability of the host to control tumor growth, making them an important population to be harnessed in the clinic for the development of anticancer therapeutics. Indeed, the identification of strong iNKT-cell agonists, such as α-galactosylceramide (α-GalCer) and its analogues, has led to the development of synthetic lipids that have shown potential in vaccination and treatment against cancers. In this Masters of Immunology article, we discuss these latest findings and summarize the major discoveries in iNKT-cell biology, which have enabled the design of potent strategies for immune-mediated tumor destruction.
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Affiliation(s)
- Rosanna M McEwen-Smith
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Headington, Oxford, United Kingdom
| | - Mariolina Salio
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Headington, Oxford, United Kingdom
| | - Vincenzo Cerundolo
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Headington, Oxford, United Kingdom.
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30
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Harris TR, Bettaieb A, Kodani S, Dong H, Myers R, Chiamvimonvat N, Haj FG, Hammock BD. Inhibition of soluble epoxide hydrolase attenuates hepatic fibrosis and endoplasmic reticulum stress induced by carbon tetrachloride in mice. Toxicol Appl Pharmacol 2015; 286:102-11. [PMID: 25827057 DOI: 10.1016/j.taap.2015.03.022] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 03/18/2015] [Accepted: 03/20/2015] [Indexed: 12/26/2022]
Abstract
Liver fibrosis is a pathological condition in which chronic inflammation and changes to the extracellular matrix lead to alterations in hepatic tissue architecture and functional degradation of the liver. Inhibitors of the enzyme soluble epoxide hydrolase (sEH) reduce fibrosis in the heart, pancreas and kidney in several disease models. In this study, we assess the effect of sEH inhibition on the development of fibrosis in a carbon tetrachloride (CCl4)-induced mouse model by monitoring changes in the inflammatory response, matrix remolding and endoplasmic reticulum stress. The sEH inhibitor 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU) was administered in drinking water. Collagen deposition in the liver was increased five-fold in the CCl4-treated group, and this was returned to control levels by TPPU treatment. Hepatic expression of Col1a2 and 3a1 mRNA was increased over fifteen-fold in the CCl4-treated group relative to the Control group, and this increase was reduced by 50% by TPPU treatment. Endoplasmic reticulum (ER) stress observed in the livers of CCl4-treated animals was attenuated by TPPU treatment. In order to support the hypothesis that TPPU is acting to reduce the hepatic fibrosis and ER stress through its action as a sEH inhibitor we used a second sEH inhibitor, trans-4-{4-[3-(4-trifluoromethoxy-phenyl)-ureido]-cyclohexyloxy}-benzoic acid (t-TUCB), and sEH null mice. Taken together, these data indicate that the sEH may play an important role in the development of hepatic fibrosis induced by CCl4, presumably by reducing endogenous fatty acid epoxide chemical mediators acting to reduce ER stress.
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Affiliation(s)
- Todd R Harris
- Department of Entomology and Comprehensive Cancer Center, University of California, Davis, CA 95616, USA
| | - Ahmed Bettaieb
- Department of Nutrition, University of California, Davis, CA 95616, USA
| | - Sean Kodani
- Department of Entomology and Comprehensive Cancer Center, University of California, Davis, CA 95616, USA
| | - Hua Dong
- Department of Entomology and Comprehensive Cancer Center, University of California, Davis, CA 95616, USA
| | - Richard Myers
- Department of Internal Medicine: Cardiovascular, University of California, Davis, CA 95616, USA
| | - Nipavan Chiamvimonvat
- Department of Internal Medicine: Cardiovascular, University of California, Davis, CA 95616, USA
| | - Fawaz G Haj
- Department of Nutrition, University of California, Davis, CA 95616, USA; Department of Internal Medicine: Endocrinology, Diabetes and Metabolism, University of California, Davis, CA 95616, USA
| | - Bruce D Hammock
- Department of Entomology and Comprehensive Cancer Center, University of California, Davis, CA 95616, USA.
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Hirsova P, Gores GJ. Death Receptor-Mediated Cell Death and Proinflammatory Signaling in Nonalcoholic Steatohepatitis. Cell Mol Gastroenterol Hepatol 2014; 1:17-27. [PMID: 25729762 PMCID: PMC4340657 DOI: 10.1016/j.jcmgh.2014.11.005] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is becoming public health problem worldwide. A subset of patients develop an inflammatory disease, nonalcoholic steatohepatitis (NASH), characterized by steatosis, hepatocellular death, macrophage and neutrophil accumulation and varying stages of fibrosis. Hepatocyte cell death triggers the cellular inflammatory response and, therefore, reducing cell death may be salutary in the steatohepatitis disease process. Recently, a better understanding of hepatocyte apoptosis in NASH has been obtained and new information regarding other cell death modes, such as necroptosis and pyroptosis, has been reported. Hepatocyte lipotoxicity is often triggered by death receptors. In addition to causing apoptosis, death receptors have been shown to mediate proinflammatory signaling, suggesting that apoptosis in this context is not an immunologically silent process. Here we review recent developments in our understanding of hepatocyte cell death by death receptors and its mechanistic link to inflammation in NASH. We emphasize how proapoptotic signaling by death receptors may induce the release of proinflammatory extracellular vesicles, thereby recruiting and activating macrophages and promoting the steatohepatitis process. Potential therapeutic strategies are discussed based on this evolving information.
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Affiliation(s)
| | - Gregory J. Gores
- Correspondence Address correspondence to: Gregory J. Gores, MD, Professor of Medicine, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, Minnesota 55905. fax: (507) 284-0762.
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Moslehi A, Nabavizadeh F, Nabavizadeh F, Dehpour AR, Dehpou AR, Tavanga SM, Hassanzadeh G, Zekri A, Nahrevanian H, Sohanaki H. Naltrexone attenuates endoplasmic reticulum stress induced hepatic injury in mice. ACTA ACUST UNITED AC 2014; 101:341-52. [PMID: 25183508 DOI: 10.1556/aphysiol.101.2014.3.9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Endoplasmic reticulum (ER) stress provides abnormalities in insulin action, inflammatory responses, lipoprotein B100 degradation and hepatic lipogenesis. Excess accumulation of triglyceride in hepatocytes may also lead to disorders such as non-alcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Opioid peptides are involved in triglyceride and cholesterol dysregulation, inflammation and cell death. In this study, we evaluated Naltrexone effects on ER stress induced liver injury. To do so, C57/BL6 mice received saline, DMSO and Naltrexone, as control groups. ER stress was induced by tunicamycin (TM) injection. Naltrexone was given before TM administration. Liver blood flow and biochemical serum analysis were measured. Histopathological evaluations, TNF-α measurement and Real-time RT-PCR were also performed. TM challenge provokes steatosis, cellular ballooning and lobular inflammation which significantly reduced in Naltrexone treated animals. ALT, AST and TNF-α increased in the TM group and improved in the Naltrexone plus TM group. Triglyceride and cholesterol levels decreased in TM treated mice with no increase in Naltrexone treated animals. In the Naltrexone plus TM group, gene expression of Bax/Bcl-2 ratio and caspase3 significantly lowered compared with the TM group. In this study, we found that Naltrexone had a notable alleviating role in ER stress induced steatosis and liver injury.
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Affiliation(s)
- A Moslehi
- Tehran University of Medical Sciences Department of Physiology, School of Medicine Tehran 1417613151 Iran
| | | | - Fatemeh Nabavizadeh
- Tehran University of Medical Sciences Department of Physiology, School of Medicine Tehran 1417613151 Iran
| | | | - A R Dehpou
- Tehran University of Medical Sciences Department of Pharmacology, School of Medicine Tehran Iran
| | - S M Tavanga
- Tehran University of Medical Sciences Shariati Hospital Tehran Iran
| | - G Hassanzadeh
- Tehran University of Medical Sciences Department of Anatomy, School of Medicine Tehran Iran
| | - A Zekri
- Tehran University of Medical Sciences Department of Genetics, School of Medicine Tehran Iran
| | - H Nahrevanian
- Pasteur Institute of Iran Department of Parasitology Tehran Iran
| | - H Sohanaki
- Iran University of Medical Sciences Department of Physiology, School of Medicine Tehran Iran
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Zhang XQ, Xu CF, Yu CH, Chen WX, Li YM. Role of endoplasmic reticulum stress in the pathogenesis of nonalcoholic fatty liver disease. World J Gastroenterol 2014; 20:1768-1776. [PMID: 24587654 PMCID: PMC3930975 DOI: 10.3748/wjg.v20.i7.1768] [Citation(s) in RCA: 201] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 09/30/2013] [Accepted: 12/06/2013] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) has emerged as a common public health problem in recent decades. However, the underlying mechanisms leading to the development of NAFLD are not fully understood. The endoplasmic reticulum (ER) stress response has recently been proposed to play a crucial role in both the development of steatosis and progression to nonalcoholic steatohepatitis. ER stress is activated to regulate protein synthesis and restore homeostatic equilibrium when the cell is stressed due to the accumulation of unfolded or misfolded proteins. However, delayed or insufficient responses to ER stress may turn physiological mechanisms into pathological consequences, including fat accumulation, insulin resistance, inflammation, and apoptosis, all of which play important roles in the pathogenesis of NAFLD. Therefore, understanding the role of ER stress in the pathogenesis of NAFLD has become a topic of intense investigation. This review highlights the recent findings linking ER stress signaling pathways to the pathogenesis of NAFLD.
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Martin-Murphy BV, You Q, Wang H, De La Houssaye BA, Reilly TP, Friedman JE, Ju C. Mice lacking natural killer T cells are more susceptible to metabolic alterations following high fat diet feeding. PLoS One 2014; 9:e80949. [PMID: 24465369 PMCID: PMC3896335 DOI: 10.1371/journal.pone.0080949] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Accepted: 10/14/2013] [Indexed: 12/12/2022] Open
Abstract
Current estimates suggest that over one-third of the adult population has metabolic syndrome and three-fourths of the obese population has non-alcoholic fatty liver disease (NAFLD). Inflammation in metabolic tissues has emerged as a universal feature of obesity and its co-morbidities, including NAFLD. Natural Killer T (NKT) cells are a subset of innate immune cells that abundantly reside within the liver and are readily activated by lipid antigens. There is general consensus that NKT cells are pivotal regulators of inflammation; however, disagreement exists as to whether NKT cells exert pathogenic or suppressive functions in obesity. Here we demonstrate that CD1d−/− mice, which lack NKT cells, were more susceptible to weight gain and fatty liver following high fat diet (HFD) feeding. Compared with their WT counterparts, CD1d−/− mice displayed increased adiposity and greater induction of inflammatory genes in the liver suggestive of the precursors of NAFLD. Calorimetry studies revealed a significant increase in food intake and trends toward decreased metabolic rate and activity in CD1d−/− mice compared with WT mice. Based on these findings, our results suggest that NKT cells play a regulatory role that helps to prevent diet-induced obesity and metabolic dysfunction and may play an important role in mechanisms governing cross-talk between metabolism and the immune system to regulate energy balance and liver health.
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Affiliation(s)
- Brittany V. Martin-Murphy
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Qiang You
- Department of Biotherapy, Second Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Hong Wang
- Division of Endocrinology, Diabetes & Metabolism, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Becky A. De La Houssaye
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Timothy P. Reilly
- Drug Safety Evaluation, Research & Development, Bristol-Myers Squibb Company, Princeton, New Jersey, United States of America
| | - Jacob E. Friedman
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Cynthia Ju
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail:
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Dowds CM, Kornell SC, Blumberg RS, Zeissig S. Lipid antigens in immunity. Biol Chem 2014; 395:61-81. [PMID: 23999493 PMCID: PMC4128234 DOI: 10.1515/hsz-2013-0220] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 08/27/2013] [Indexed: 02/07/2023]
Abstract
Lipids are not only a central part of human metabolism but also play diverse and critical roles in the immune system. As such, they can act as ligands of lipid-activated nuclear receptors, control inflammatory signaling through bioactive lipids such as prostaglandins, leukotrienes, lipoxins, resolvins, and protectins, and modulate immunity as intracellular phospholipid- or sphingolipid-derived signaling mediators. In addition, lipids can serve as antigens and regulate immunity through the activation of lipid-reactive T cells, which is the topic of this review. We will provide an overview of the mechanisms of lipid antigen presentation, the biology of lipid-reactive T cells, and their contribution to immunity.
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Affiliation(s)
- C. Marie Dowds
- Department of Internal Medicine I, University Medical Center
Schleswig-Holstein, Schittenhelmstraße 12, D-24105 Kiel,
Germany
| | - Sabin-Christin Kornell
- Department of Internal Medicine I, University Medical Center
Schleswig-Holstein, Schittenhelmstraße 12, D-24105 Kiel,
Germany
| | - Richard S. Blumberg
- Division of Gastroenterology, Hepatology, and Endoscopy, Brigham
and Women’s Hospital, Harvard Medical School, 75 Francis Street,
Boston, MA 02115, USA
| | - Sebastian Zeissig
- Department of Internal Medicine I, University Medical Center
Schleswig-Holstein, Schittenhelmstraße 12, D-24105 Kiel,
Germany
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Tang T, Sui Y, Lian M, Li Z, Hua J. Pro-inflammatory activated Kupffer cells by lipids induce hepatic NKT cells deficiency through activation-induced cell death. PLoS One 2013; 8:e81949. [PMID: 24312613 PMCID: PMC3849421 DOI: 10.1371/journal.pone.0081949] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Accepted: 10/18/2013] [Indexed: 12/21/2022] Open
Abstract
Background Dietary lipids play an important role in the progression of non-alcoholic fatty liver disease (NAFLD) through alternation of liver innate immune response. Aims The present study was to investigate the effect of lipid on Kupffer cells phenotype and function invivo and invitro. And further to investigate the impact of lipid on ability of Kupffer cell lipid antigen presentation to activate NKT cells. Methods Wild type male C57BL/6 mice were fed either normal or high-fat diet. Hepatic steatosis, Kupffer cell abundance, NKT cell number and cytokine gene expression were evaluated. Antigen presentation assay was performed with Kupffer cells treated with certain fatty acids invitro and co-cultured with NKT cells. Results High-fat diet induced hepatosteatosis, significantly increased Kupffer cells and decreased hepatic NKT cells. Lipid treatment invivo or invitro induced increase of pro-inflammatory cytokines gene expression and toll-like receptor 4 (TLR4) expression in Kupffer cells. Kupffer cells expressed high levels of CD1d on cell surface and only presented exogenous lipid antigen to activate NKT cells. Ability of Kupffer cells to present antigen and activate NKT cells was enhanced after lipid treatment. In addition, pro-inflammatory activated Kupffer cells by lipid treatment induced hepatic NKT cells activation-induced apoptosis and necrosis. Conclusion High-fat diet increase Kupffer cells number and induce their pro-inflammatory status. Pro-inflammatory activated Kupfffer cells by lipid promote hepatic NKT cell over-activation and cell death, which lead to further hepatic NKT cell deficiency in the development of NAFLD.
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Affiliation(s)
- Tongfang Tang
- Division of Gastroenterology and Hepatology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Digestive Disease, Shanghai ,P.R.China
| | - Yongheng Sui
- Division of Gastroenterology and Hepatology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Digestive Disease, Shanghai ,P.R.China
| | - Min Lian
- Division of Gastroenterology and Hepatology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Digestive Disease, Shanghai ,P.R.China
| | - Zhiping Li
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Jing Hua
- Division of Gastroenterology and Hepatology, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Digestive Disease, Shanghai ,P.R.China
- * E-mail:
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Yang CY, Chen JB, Tsai TF, Tsai YC, Tsai CY, Liang PH, Hsu TL, Wu CY, Netea MG, Wong CH, Hsieh SL. CLEC4F is an inducible C-type lectin in F4/80-positive cells and is involved in alpha-galactosylceramide presentation in liver. PLoS One 2013; 8:e65070. [PMID: 23762286 PMCID: PMC3675125 DOI: 10.1371/journal.pone.0065070] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 04/21/2013] [Indexed: 01/19/2023] Open
Abstract
CLEC4F, a member of C-type lectin, was first purified from rat liver extract with high binding affinity to fucose, galactose (Gal), N-acetylgalactosamine (GalNAc), and un-sialylated glucosphingolipids with GalNAc or Gal terminus. However, the biological functions of CLEC4F have not been elucidated. To address this question, we examined the expression and distribution of murine CLEC4F, determined its binding specificity by glycan array, and investigated its function using CLEC4F knockout (Clec4f-/-) mice. We found that CLEC4F is a heavily glycosylated membrane protein co-expressed with F4/80 on Kupffer cells. In contrast to F4/80, CLEC4F is detectable in fetal livers at embryonic day 11.5 (E11.5) but not in yolk sac, suggesting the expression of CLEC4F is induced as cells migrate from yolk cells to the liver. Even though CLEC4F is not detectable in tissues outside liver, both residential Kupffer cells and infiltrating mononuclear cells surrounding liver abscesses are CLEC4F-positive upon Listeria monocytogenes (L. monocytogenes) infection. While CLEC4F has strong binding to Gal and GalNAc, terminal fucosylation inhibits CLEC4F recognition to several glycans such as Fucosyl GM1, Globo H, Bb3∼4 and other fucosyl-glycans. Moreover, CLEC4F interacts with alpha-galactosylceramide (α-GalCer) in a calcium-dependent manner and participates in the presentation of α-GalCer to natural killer T (NKT) cells. This suggests that CLEC4F is a C-type lectin with diverse binding specificity expressed on residential Kupffer cells and infiltrating monocytes in the liver, and may play an important role to modulate glycolipids presentation on Kupffer cells.
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Affiliation(s)
- Chih-Ya Yang
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan
- Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan
| | - Jiun-Bo Chen
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan
| | - Ting-Fen Tsai
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Chen Tsai
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan
| | - Ching-Yen Tsai
- Transgenic Core Facility, Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Pi-Hui Liang
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Tsui-Ling Hsu
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Chung-Yi Wu
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Mihai G. Netea
- Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
| | - Chi-Huey Wong
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Shie-Liang Hsieh
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
- Institute of Clinical Medicine & Infection and Immunity Center, National Yang-Ming University, Taipei, Taiwan
- Immunology Center, Taipei Veterans General Hospital, Taipei, Taiwan
- The Institute for Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
- * E-mail:
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Jo H, Choe SS, Shin KC, Jang H, Lee JH, Seong JK, Back SH, Kim JB. Endoplasmic reticulum stress induces hepatic steatosis via increased expression of the hepatic very low-density lipoprotein receptor. Hepatology 2013; 57:1366-77. [PMID: 23152128 DOI: 10.1002/hep.26126] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 10/20/2012] [Indexed: 12/11/2022]
Abstract
UNLABELLED Recent evidence suggests that obese animals exhibit increased endoplasmic reticulum (ER) stress in the liver and adipose tissue. Although ER stress is closely associated with lipid homeostasis, it is largely unknown how ER stress contributes to hepatic steatosis. In this study, we demonstrate that the induction of ER stress stimulates hepatic steatosis through increased expression of the hepatic very low-density lipoprotein receptor (VLDLR). Among the unfolded protein response sensors, the protein kinase RNA-like ER kinase-activating transcription factor 4 signaling pathway was required for hepatic VLDLR up-regulation. In primary hepatocytes, ER stress-dependent VLDLR expression induced intracellular triglyceride accumulation in the presence of very low-density lipoprotein. Moreover, ER stress-dependent hepatic steatosis was diminished in the livers of VLDLR-deficient and apolipoprotein E-deficient mice compared with wild-type mice. In addition, the VLDLR-deficient mice exhibited decreased hepatic steatosis upon high-fat diet feeding. CONCLUSION These data suggest that ER stress-dependent expression of hepatic VLDLR leads to hepatic steatosis by increasing lipoprotein delivery to the liver, which might be a novel mechanism explaining ER stress-induced hepatic steatosis.
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Affiliation(s)
- Hyunsun Jo
- School of Biological Sciences, Institute of Molecular Biology and Genetics, University of Ulsan, Ulsan, Korea
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Wu L, Van Kaer L. Contribution of lipid-reactive natural killer T cells to obesity-associated inflammation and insulin resistance. Adipocyte 2013; 2:12-16. [PMID: 23700548 PMCID: PMC3661135 DOI: 10.4161/adip.22296] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Obesity is associated with a low-grade, chronic inflammation that promotes the development of a variety of diseases, most notably type 2 diabetes. A number of cell types of the innate and adaptive immune systems have been implicated in this process. Recent studies have focused on the role of natural killer T (NKT) cells, a subset of T lymphocytes that react with lipids, in the development of obesity-associated diseases. These studies have shown that invariant NKT (iNKT) cells, a population of NKT cells expressing a semi-invariant T cell receptor, become rapidly activated in response to lipid excess, and that these cells influence the capacity of other leukocytes to produce cytokines during the progression of obesity. The role of NKT cells in obesity-associated inflammation and insulin resistance has been investigated using NKT cell-deficient animals, adoptive transfer of NKT cells and an iNKT cell agonist. While divergent results have been obtained, it is now clear that NKT cells can modulate the inflammatory milieu in obesity, suggesting that these cells could be targeted for therapeutic intervention in obesity-associated diseases.
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40
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Monzon-Casanova E, Paletta D, Starick L, Müller I, Sant'Angelo DB, Pyz E, Herrmann T. Direct identification of rat iNKT cells reveals remarkable similarities to human iNKT cells and a profound deficiency in LEW rats. Eur J Immunol 2012; 43:404-15. [PMID: 23165932 DOI: 10.1002/eji.201242565] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 10/29/2012] [Accepted: 11/14/2012] [Indexed: 12/18/2022]
Abstract
iNKT cells are a particular lymphocyte population with potent immunomodulatory capa-city; by promoting or suppressing immune responses against infections, tumors, and autoimmunity, iNKT cells are a promising target for immunotherapy. The hallmark of iNKT cells is the expression of a semiinvariant TCR (with an invariant α-chain comprising AV14 and AJ18 gene segments), which recognizes glycolipids presented by CD1d. Here, we identified iNKT cells for the first time in the rat using rat CD1d-dimers and PLZF staining. Importantly, in terms of frequencies (1.05% ± 0.52 SD of all intrahepatic αβ T cells), coreceptor expression and in vitro expansion features, iNKT cells from F344 inbred rats more closely resemble human iNKT cells than their mouse counterparts. In contrast, in LEW inbred rats, which are often used as models for organ-specific autoimmune diseases, iNKT cell numbers are near or below the detection limit. Interestingly, the usage of members of the rat AV14 gene family differed between F344 and LEW inbred rats. In conclusion, the similarities between F344 rat and human iNKT cells and the nearly absent iNKT cells in LEW rats make the rat a promising animal model for the study of iNKT cell-based therapies and of iNKT-cell biology.
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Affiliation(s)
- Elisa Monzon-Casanova
- Institute for Virology and Immunobiology, Julius-Maximilians-University of Würzburg, Würzburg, Germany
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Machado MV, Yang Y, Diehl AM. The benefits of restraint: a pivotal role for IL-13 in hepatic glucose homeostasis. J Clin Invest 2012; 123:115-7. [PMID: 23257364 DOI: 10.1172/jci67238] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
In response to feeding, insulin promotes the uptake of sugar in peripheral tissues and suppresses the production of sugar, a process called gluconeogenesis, in the liver. Recent research has shown that chronic inflammation promotes insulin resistance, and in turn, chronically high glucose levels can drive inflammation. In this issue of the JCI, Stanya et al. investigate the connection between inflammation and glucose homeostasis by analyzing the effect of the antiinflammatory cytokine IL-13. Their results suggest that IL-13 plays an unexpected role in the regulation of glucose homeostasis by modulating gluconeogenesis and may be a useful therapeutic target for treatment of diabetes and metabolic syndrome.
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42
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Lynch L, Nowak M, Varghese B, Clark J, Hogan AE, Toxavidis V, Balk SP, O'Shea D, O'Farrelly C, Exley MA. Adipose tissue invariant NKT cells protect against diet-induced obesity and metabolic disorder through regulatory cytokine production. Immunity 2012; 37:574-87. [PMID: 22981538 DOI: 10.1016/j.immuni.2012.06.016] [Citation(s) in RCA: 378] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 05/23/2012] [Accepted: 06/07/2012] [Indexed: 12/13/2022]
Abstract
Invariant natural killer T (iNKT) cells are evolutionarily conserved innate T cells that influence inflammatory responses. We have shown that iNKT cells, previously thought to be rare in humans, were highly enriched in human and murine adipose tissue, and that as adipose tissue expanded in obesity, iNKT cells were depleted, correlating with proinflammatory macrophage infiltration. iNKT cell numbers were restored in mice and humans after weight loss. Mice lacking iNKT cells had enhanced weight gain, larger adipocytes, fatty livers, and insulin resistance on a high-fat diet. Adoptive transfer of iNKT cells into obese mice or in vivo activation of iNKT cells via their lipid ligand, alpha-galactocylceramide, decreased body fat, triglyceride levels, leptin, and fatty liver and improved insulin sensitivity through anti-inflammatory cytokine production by adipose-derived iNKT cells. This finding highlights the potential of iNKT cell-targeted therapies, previously proven to be safe in humans, in the management of obesity and its consequences.
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Affiliation(s)
- Lydia Lynch
- Hematology/Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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43
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Wu L, Parekh VV, Gabriel CL, Bracy DP, Marks-Shulman PA, Tamboli RA, Kim S, Mendez-Fernandez YV, Besra GS, Lomenick JP, Williams B, Wasserman DH, Van Kaer L. Activation of invariant natural killer T cells by lipid excess promotes tissue inflammation, insulin resistance, and hepatic steatosis in obese mice. Proc Natl Acad Sci U S A 2012; 109:E1143-52. [PMID: 22493234 PMCID: PMC3358828 DOI: 10.1073/pnas.1200498109] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Obesity triggers a low-grade systemic inflammation, which plays an important role in the development of obesity-associated metabolic diseases. In searching for links between lipid accumulation and chronic inflammation, we examined invariant natural killer T (iNKT) cells, a subset of T lymphocytes that react with lipids and regulate inflammatory responses. We show that iNKT cells respond to dietary lipid excess and become activated before or at the time of tissue recruitment of inflammatory leukocytes, and that these cells progressively increase proinflammatory cytokine production in obese mice. Such iNKT cells skew other leukocytes toward proinflammatory cytokine production and induce an imbalanced proinflammatory cytokine environment in multiple tissues. Further, iNKT cell deficiency ameliorates tissue inflammation and provides protection against obesity-induced insulin resistance and hepatic steatosis. Conversely, chronic iNKT cell stimulation using a canonical iNKT cell agonist exacerbates tissue inflammation and obesity-associated metabolic disease. These findings place iNKT cells into the complex network linking lipid excess to inflammation in obesity and suggest new therapeutic avenues for obesity-associated metabolic disorders.
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Affiliation(s)
- Lan Wu
- Departments of Microbiology and Immunology
| | | | | | - Deanna P. Bracy
- Molecular Physiology and Biophysics, and
- Vanderbilt–National Institutes of Health Mouse Metabolic Phenotyping Center, Vanderbilt University School of Medicine, Nashville, TN 37232; and
| | | | | | | | | | - Gurdyal S. Besra
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | | | | | - David H. Wasserman
- Molecular Physiology and Biophysics, and
- Vanderbilt–National Institutes of Health Mouse Metabolic Phenotyping Center, Vanderbilt University School of Medicine, Nashville, TN 37232; and
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44
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Cao J, Dai DL, Yao L, Yu HH, Ning B, Zhang Q, Chen J, Cheng WH, Shen W, Yang ZX. Saturated fatty acid induction of endoplasmic reticulum stress and apoptosis in human liver cells via the PERK/ATF4/CHOP signaling pathway. Mol Cell Biochem 2012. [PMID: 22246806 DOI: 10.1007/s11010-011-12211-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Accumulation of saturated fatty acids in the liver can cause nonalcoholic fatty liver disease (NAFLD). This study investigated saturated fatty acid induction of endoplasmic reticulum (ER) stress and apoptosis in human liver cells and the underlying causal mechanism. Human liver L02 and HepG2 cell lines were exposed to the saturated fatty acid sodium palmitate. MTT assay was used for cell viability, flow cytometry and Hoechst 33258 staining for apoptosis, RT-PCR for mRNA expression, and Western blot for protein expression. Silence of PRK-like ER kinase (PERK) expression in liver cells was through transient transfection of PERK shRNA. Treatment of L02 and HepG2 cells with sodium palmitate reduced cell viability through induction of apoptosis. Sodium palmitate also induced ER stress in the cells, indicated by upregulation of PERK phosphorylation and expression of BiP, ATF4, and CHOP proteins. Sodium palmitate had little effect on activating XBP-1, a common target of the other two canonical sensors of ER stress, ATF6, and IRE1. Knockdown of PERK gene expression suppressed the PERK/ATF4/CHOP signaling pathway during sodium palmitate-induced ER stress and significantly inhibited sodium palmitate-induced apoptosis in L02 and HepG2 cells. Saturated fatty acid-induced ER stress and apoptosis in these human liver cells were enacted through the PERK/ATF4/CHOP signaling pathway. Future study is warranted to investigate the role of these proteins in mediating saturated fatty acid-induced NAFLD in animal models.
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Affiliation(s)
- Jie Cao
- Department of Gastroenterology and Hepatology, 2nd Affiliated Hospital of Chongqing Medical University, No. 74 Linjiang Road, Chongqing 400010, China
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Cao J, Dai DL, Yao L, Yu HH, Ning B, Zhang Q, Chen J, Cheng WH, Shen W, Yang ZX. Saturated fatty acid induction of endoplasmic reticulum stress and apoptosis in human liver cells via the PERK/ATF4/CHOP signaling pathway. Mol Cell Biochem 2012; 364:115-29. [PMID: 22246806 DOI: 10.1007/s11010-011-1211-9] [Citation(s) in RCA: 168] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 12/21/2011] [Indexed: 12/22/2022]
Abstract
Accumulation of saturated fatty acids in the liver can cause nonalcoholic fatty liver disease (NAFLD). This study investigated saturated fatty acid induction of endoplasmic reticulum (ER) stress and apoptosis in human liver cells and the underlying causal mechanism. Human liver L02 and HepG2 cell lines were exposed to the saturated fatty acid sodium palmitate. MTT assay was used for cell viability, flow cytometry and Hoechst 33258 staining for apoptosis, RT-PCR for mRNA expression, and Western blot for protein expression. Silence of PRK-like ER kinase (PERK) expression in liver cells was through transient transfection of PERK shRNA. Treatment of L02 and HepG2 cells with sodium palmitate reduced cell viability through induction of apoptosis. Sodium palmitate also induced ER stress in the cells, indicated by upregulation of PERK phosphorylation and expression of BiP, ATF4, and CHOP proteins. Sodium palmitate had little effect on activating XBP-1, a common target of the other two canonical sensors of ER stress, ATF6, and IRE1. Knockdown of PERK gene expression suppressed the PERK/ATF4/CHOP signaling pathway during sodium palmitate-induced ER stress and significantly inhibited sodium palmitate-induced apoptosis in L02 and HepG2 cells. Saturated fatty acid-induced ER stress and apoptosis in these human liver cells were enacted through the PERK/ATF4/CHOP signaling pathway. Future study is warranted to investigate the role of these proteins in mediating saturated fatty acid-induced NAFLD in animal models.
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Affiliation(s)
- Jie Cao
- Department of Gastroenterology and Hepatology, 2nd Affiliated Hospital of Chongqing Medical University, No. 74 Linjiang Road, Chongqing 400010, China
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Role of NKT Cells in the Pathogenesis of NAFLD. Int J Hepatol 2012; 2012:850836. [PMID: 22577564 PMCID: PMC3335183 DOI: 10.1155/2012/850836] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 01/12/2012] [Accepted: 01/23/2012] [Indexed: 12/16/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most frequent chronic liver disease and shows various inflammatory changes in the liver. Among those inflammatory cells, natural killer T (NKT) cells are found to have a critical role during the disease progression. NKT cells may have a protective role at the early stage with simple steatosis through modification of insulin resistance, whereas they act as a progression factor at the advanced stage with fibrosis. Those processes are thought to depend on interaction between NKT cells and CD1d molecule in the liver.
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Kotas ME, Lee HY, Gillum MP, Annicelli C, Guigni BA, Shulman GI, Medzhitov R. Impact of CD1d deficiency on metabolism. PLoS One 2011; 6:e25478. [PMID: 21980475 PMCID: PMC3183002 DOI: 10.1371/journal.pone.0025478] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 09/05/2011] [Indexed: 01/29/2023] Open
Abstract
Invariant natural killer T cells (iNKTs) are innate-like T cells that are highly concentrated in the liver and recognize lipids presented on the MHC-like molecule CD1d. Although capable of a myriad of responses, few essential functions have been described for iNKTs. Among the many cell types of the immune system implicated in metabolic control and disease, iNKTs seem ideally poised for such a role, yet little has been done to elucidate such a possible function. We hypothesized that lipid presentation by CD1d could report on metabolic status and engage iNKTs to regulate cellular lipid content through their various effector mechanisms. To test this hypothesis, we examined CD1d deficient mice in a variety of metabolically stressed paradigms including high fat feeding, choline-deficient feeding, fasting, and acute inflammation. CD1d deficiency led to a mild exacerbation of steatosis during high fat or choline-deficient feeding, accompanied by impaired hepatic glucose tolerance. Surprisingly, however, this phenotype was not observed in Jα18⁻/⁻ mice, which are deficient in iNKTs but express CD1d. Thus, CD1d appears to modulate some metabolic functions through an iNKT-independent mechanism.
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Affiliation(s)
- Maya E Kotas
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America.
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Gambino R, Musso G, Cassader M. Redox balance in the pathogenesis of nonalcoholic fatty liver disease: mechanisms and therapeutic opportunities. Antioxid Redox Signal 2011; 15:1325-65. [PMID: 20969475 DOI: 10.1089/ars.2009.3058] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is currently the most common liver disease in the world. It encompasses a histological spectrum, ranging from simple, nonprogressive steatosis to nonalcoholic steatohepatitis (NASH), which may progress to cirrhosis and hepatocellular carcinoma. While liver-related complications are confined to NASH, emerging evidence suggests both simple steatosis and NASH predispose to type 2 diabetes and cardiovascular disease. The pathogenesis of NAFLD is currently unknown, but accumulating data suggest that oxidative stress and altered redox balance play a crucial role in the pathogenesis of steatosis, steatohepatitis, and fibrosis. We will examine intracellular mechanisms, including mitochondrial dysfunction and impaired oxidative free fatty acid metabolism, leading to reactive oxygen species generation; additionally, the potential pathogenetic role of extracellular sources of reactive oxygen species in NAFLD, including increased myeloperoxidase activity and oxidized low density lipoprotein accumulation, will be reviewed. We will discuss how these mechanisms converge to determine the whole pathophysiological spectrum of NAFLD, including hepatocyte triglyceride accumulation, hepatocyte apoptosis, hepatic inflammation, hepatic stellate cell activation, and fibrogenesis. Finally, available animal and human data on treatment opportunities with older and newer antioxidant will be presented.
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Affiliation(s)
- Roberto Gambino
- Department of Internal Medicine, University of Turin, Turin, Italy
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Mantell BS, Stefanovic-Racic M, Yang X, Dedousis N, Sipula IJ, O'Doherty RM. Mice lacking NKT cells but with a complete complement of CD8+ T-cells are not protected against the metabolic abnormalities of diet-induced obesity. PLoS One 2011; 6:e19831. [PMID: 21674035 PMCID: PMC3108591 DOI: 10.1371/journal.pone.0019831] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 04/18/2011] [Indexed: 12/12/2022] Open
Abstract
The contribution of natural killer T (NKT) cells to the pathogenesis of metabolic abnormalities of obesity is controversial. While the combined genetic deletion of NKT and CD8(+) T-cells improves glucose tolerance and reduces inflammation, interpretation of these data have been complicated by the recent observation that the deletion of CD8(+) T-cells alone reduces obesity-induced inflammation and metabolic dysregulation, leaving the issue of the metabolic effects of NKT cell depletion unresolved. To address this question, CD1d null mice (CD1d(-/-)), which lack NKT cells but have a full complement of CD8(+) T-cells, and littermate wild type controls (WT) on a pure C57BL/6J background were exposed to a high fat diet, and glucose intolerance, insulin resistance, dyslipidemia, inflammation, and obesity were assessed. Food intake (15.5±4.3 vs 15.3±1.8 kcal/mouse/day), weight gain (21.8±1.8 vs 22.8±1.4 g) and fat mass (18.6±1.9 vs 19.5±2.1 g) were similar in CD1d(-/-) and WT, respectively. As would be expected from these data, metabolic rate (3.0±0.1 vs 2.9±0.2 ml O(2)/g/h) and activity (21.6±4.3 vs 18.5±2.6 beam breaks/min) were unchanged by NKT cell depletion. Furthermore, the degree of insulin resistance, glucose intolerance, liver steatosis, and adipose and liver inflammatory marker expression (TNFα, IL-6, IL-10, IFN-γ, MCP-1, MIP1α) induced by high fat feeding in CD1d(-/-) were not different from WT. We conclude that deletion of NKT cells, in the absence of alterations in the CD8(+) T-cell population, is insufficient to protect against the development of the metabolic abnormalities of diet-induced obesity.
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Affiliation(s)
- Benjamin S. Mantell
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Maja Stefanovic-Racic
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Xiao Yang
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Nikolas Dedousis
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Ian J. Sipula
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Robert M. O'Doherty
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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Fructose-induced steatosis in mice: role of plasminogen activator inhibitor-1, microsomal triglyceride transfer protein and NKT cells. J Transl Med 2011; 91:885-95. [PMID: 21423135 DOI: 10.1038/labinvest.2011.44] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Plasminogen activator inhibitor-1 (PAI-1) is an acute-phase protein known to be involved in alcoholic liver disease and hepatic fibrosis. In the present study, the hypothesis that PAI-1 is causally involved in the onset of fructose-induced hepatic steatosis was tested in a mouse model. Wild-type C57BL/6J and PAI-1⁻/⁻ mice were fed with 30% fructose solution or water for 8 weeks. Markers of hepatic steatosis, expression of PAI-1, apolipoprotein B (ApoB), cluster of differentiation 1d (CD1d), markers of natural killer T (NKT) cells, protein levels of phospho-c-Met and tumor necrosis factor-α (TNF-α) were determined. Activity of the microsomal triglyceride transfer protein (MTTP) was measured in liver tissue. In comparison with water controls, chronic intake of 30% fructose solution caused a significant increase in hepatic triglycerides, PAI-1 expression and plasma alanine aminotransferase levels in wild-type mice. This effect of fructose feeding was markedly attenuated in PAI-1⁻/⁻ mice. Despite no differences in portal endotoxin levels and hepatic TNF-α protein levels between fructose-fed groups, the protective effect of the loss of PAI-1 against the onset of fructose-induced steatosis was associated with a significant increase in phospho-c-Met, phospho Akt, expression of ApoB and activity of MTTP in livers of PAI-1⁻/⁻ mice in comparison with fructose-fed wild types. Moreover, in PAI-1⁻/⁻ mice, expressions of CD1d and markers of CD1d-reactive NKT cells were markedly higher than in wild-type mice; however, expression of markers of activation of CD1d-reactive NKT cells (eg, interleukin-15 and interferon-γ) were only found to be increased in livers of fructose-fed PAI-1⁻/⁻ mice. Taken together, these data suggest that PAI-1 has a causal role in mediating the early phase of fructose-induced liver damage in mice through signaling cascades downstream of Kupffer cells and TNF-α.
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