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Li X, Ren Y, Chang K, Wu W, Griffiths HR, Lu S, Gao D. Adipose tissue macrophages as potential targets for obesity and metabolic diseases. Front Immunol 2023; 14:1153915. [PMID: 37153549 PMCID: PMC10154623 DOI: 10.3389/fimmu.2023.1153915] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 04/04/2023] [Indexed: 05/09/2023] Open
Abstract
Macrophage infiltration into adipose tissue is a key pathological factor inducing adipose tissue dysfunction and contributing to obesity-induced inflammation and metabolic disorders. In this review, we aim to present the most recent research on macrophage heterogeneity in adipose tissue, with a focus on the molecular targets applied to macrophages as potential therapeutics for metabolic diseases. We begin by discussing the recruitment of macrophages and their roles in adipose tissue. While resident adipose tissue macrophages display an anti-inflammatory phenotype and promote the development of metabolically favorable beige adipose tissue, an increase in pro-inflammatory macrophages in adipose tissue has negative effects on adipose tissue function, including inhibition of adipogenesis, promotion of inflammation, insulin resistance, and fibrosis. Then, we presented the identities of the newly discovered adipose tissue macrophage subtypes (e.g. metabolically activated macrophages, CD9+ macrophages, lipid-associated macrophages, DARC+ macrophages, and MFehi macrophages), the majority of which are located in crown-like structures within adipose tissue during obesity. Finally, we discussed macrophage-targeting strategies to ameliorate obesity-related inflammation and metabolic abnormalities, with a focus on transcriptional factors such as PPARγ, KLF4, NFATc3, and HoxA5, which promote macrophage anti-inflammatory M2 polarization, as well as TLR4/NF-κB-mediated inflammatory pathways that activate pro-inflammatory M1 macrophages. In addition, a number of intracellular metabolic pathways closely associated with glucose metabolism, oxidative stress, nutrient sensing, and circadian clock regulation were examined. Understanding the complexities of macrophage plasticity and functionality may open up new avenues for the development of macrophage-based treatments for obesity and other metabolic diseases.
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Affiliation(s)
- Xirong Li
- Institute of Molecular and Translational Medicine, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Yakun Ren
- Institute of Molecular and Translational Medicine, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Kewei Chang
- Institute of Molecular and Translational Medicine, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
- Key Laboratory of Environment and Genes Related to Diseases (Xi’an Jiaotong University), Ministry of Education, Xi’an, China
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Center, Xi’an, China
| | - Wenlong Wu
- Institute of Molecular and Translational Medicine, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Helen R. Griffiths
- Swansea University Medical School, Swansea University, Swansea, United Kingdom
| | - Shemin Lu
- Institute of Molecular and Translational Medicine, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
- Key Laboratory of Environment and Genes Related to Diseases (Xi’an Jiaotong University), Ministry of Education, Xi’an, China
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
| | - Dan Gao
- Institute of Molecular and Translational Medicine, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, China
- Key Laboratory of Environment and Genes Related to Diseases (Xi’an Jiaotong University), Ministry of Education, Xi’an, China
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Center, Xi’an, China
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Abstract
PURPOSE OF REVIEW We reviewed recent progress on the role of sclerostin (SOST) and its effects on the immune system in order to summarize the current state of knowledge in osteoimmunology, in regard to hematopoiesis, lymphopoiesis, and inflammation. RECENT FINDINGS Changes in sclerostin levels affect distinct niches within the bone marrow that support hematopoietic stem cells and B cell development. Sclerostin's regulation of adipogenesis could also be important for immune cell maintenance with age. Surprisingly, B cell development in the bone marrow is influenced by Sost produced by mesenchymal stem cells and osteoblasts, but not by osteocytes. Additionally, extramedullary hematopoiesis in the spleen and increased pro-inflammatory cytokine levels in the bone marrow are observed in global Sost-/- mice. In addition to changes in bone marrow density, sclerostin depletion affects B lymphopoiesis and myelopoiesis, as well as other changes within the bone marrow cavity that could affect hematopoiesis. It is therefore important to monitor for hematopoietic changes in patients receiving sclerostin-depleting therapies.
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Affiliation(s)
- Cristine Donham
- Quantitative and Systems Biology Graduate Program, University of California, Merced, Merced, CA, 95343, USA
| | - Jennifer O Manilay
- Quantitative and Systems Biology Graduate Program, University of California, Merced, Merced, CA, 95343, USA.
- Dept. of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, 5200, Lake Road Merced, North, CA, 95343, USA.
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Sun J, Bian C, Ji S, Luo X, Ji H. Greater potency of adipocytes compared with preadipocytes under lipopolysaccharide exposure in grass carp Ctenopharyngodon idella. Fish Shellfish Immunol 2019; 91:343-349. [PMID: 31042574 DOI: 10.1016/j.fsi.2019.04.295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 04/23/2019] [Accepted: 04/26/2019] [Indexed: 06/09/2023]
Abstract
Excessive body fat is a chronic inflammatory disorder. In this process, white adipose tissue (WAT) performs immune activities because of the dysregulated expression of adipokines. Excessive fat is accumulated in farmed fish, thereby threatening fish health. Studies have shown that adipose tissue is also an active immune organ in fish, capable of participating in and influencing immune responses. Adipocytes are the main cellular component of adipose tissue; however, little is known about the relationship between adipocyte and inflammation in fish. In this study, we analyzed transcriptome changes during adipogenesis in the primary culture of grass carp adipocytes using bioinformatics. The results showed that inflammatory signaling pathway may be activated during grass carp adipocyte differentiation, such as NFκB signaling pathway, Toll-like receptor signaling pathway and Adipocytokine signaling pathway, indicating that grass carp adipocytes have immune activities. Exposure to LPS induced expression of adipokines genes in adipocytes and preadipocytes, including NF-kB, IL-6, MCP-1 and TNFα, suggesting that preadipocytes and adipocytes both have immune response and the immune activity is conserved in vertebrates white adipocytes. Further study found that these immune marker genes were higher expressed in adipocytes compared with preadipocytes in LPS-induced inflammation. In summary, adipocyte should be considered as an active immune site in fish. Adipocytes have greater potency compared with preadipocytes in LPS-induced inflammation. This study indicated that adipocytes and preadipocytes may have different contribution in inflammation.
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Affiliation(s)
- Jian Sun
- College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling 712100, China
| | - ChenChen Bian
- College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling 712100, China
| | - ShangHong Ji
- College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling 712100, China
| | - XiaoLong Luo
- College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling 712100, China
| | - Hong Ji
- College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling 712100, China.
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Kilroy G, Dietrich M, Wu X, Gimble JM, Floyd ZE. Isolation of Murine Adipose-Derived Stromal/Stem Cells for Adipogenic Differentiation or Flow Cytometry-Based Analysis. Methods Mol Biol 2019; 1773:137-146. [PMID: 29687386 DOI: 10.1007/978-1-4939-7799-4_11] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Murine models of obesity or reduced adiposity are a valuable resource for understanding the role of adipocyte dysfunction in metabolic disorders. Adipose tissue stromal vascular cells or primary adipocytes derived from murine adipose tissue and grown in culture are essential tools for studying the mechanisms underlying adipocyte development and function. Herein, we describe methods for the isolation, expansion, and long-term storage of murine adipose-derived stromal/stem cells along with protocols for inducing adipogenesis in this cell population or isolating the adipose stromal vascular fraction cells for flow cytometric analysis.
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Affiliation(s)
- Gail Kilroy
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA
| | - Marilyn Dietrich
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA
| | | | | | - Z Elizabeth Floyd
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA.
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Chang CC, Chen CY, Wen HC, Huang CY, Hung MS, Lu HC, Chen WL, Chang CH. Caveolin-1 Secreted from Adipose Tissues and Adipocytes Functions as an Adipogenesis Enhancer. Obesity (Silver Spring) 2017; 25:1932-1940. [PMID: 28944626 DOI: 10.1002/oby.21970] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 07/11/2017] [Accepted: 07/24/2017] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Caveolin-1 (Cav-1) is expressed abundantly in adipose tissue and involved in many physiological processes. While Cav-1 has been reported to be secreted in pancreatic acinar cells and LNCaP prostate cancer cells, its secretion from adipose tissue awaits investigation. METHODS Cav-1 secretion from 3T3-L1 adipocytes and fat tissues from normal chow diet- and high-fat diet (HFD)-fed mice was measured. Functions and uptake of secreted Cav-1 proteins were assessed by adding Cav-1 back to preadipocytes and LNCaP cells. RESULTS Cav-1 secretion was evident in adipose tissues and were substantially promoted in HFD-fed mice. Cav-1 was detectable in the conditioned media of 3T3-L1 adipocytes but not preadipocytes. Hypertrophied adipocytes induced by glucose and fatty acids secreted more Cav-1, suggesting that hypertrophied adipocytes were responsible for enhanced Cav-1 secretion in obese mice. Secreted Cav-1 was taken up by preadipocytes and LNCaP cells. 3T3-L1 preadipocytes overexpressing Cav-1 were better differentiated, suggesting that secreted Cav-1 may promote adipogenesis. Hypertrophied 3T3-L1 adipocytes enhanced ERK1/2 activation, and the attenuation of ERK1/2 activity by PD98059 inhibited Cav-1 secretion. CONCLUSIONS Cav-1 is actively secreted from adipocytes as a putative adipogenesis enhancer. Hypertrophied adipocytes secrete Cav-1 via ERK1/2-dependent mechanisms to promote adipogenesis, thus establishing a vicious cycle.
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Affiliation(s)
- Chia-Chu Chang
- PhD Program for Aging, China Medical University, Taichung, Taiwan, Republic of China
- School of Medicine, Chung Shan Medical University, Taichung, Taiwan, Republic of China
- Environmental and Precision Medicine Laboratory, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, Republic of China
| | - Chen-Yu Chen
- Institute of Cellular and System Medicine, National Health Research Institutes, Zhunan, Miaoli, Taiwan, Republic of China
| | - Hui-Chin Wen
- Institute of Cellular and System Medicine, National Health Research Institutes, Zhunan, Miaoli, Taiwan, Republic of China
| | - Chih-Yang Huang
- PhD Program for Aging, China Medical University, Taichung, Taiwan, Republic of China
| | - Ming-Shiu Hung
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, Miaoli, Taiwan, Republic of China
| | - Hsi-Chi Lu
- Department of Food Science, Tunghai University, Taichung, Taiwan, Republic of China
| | - Woan-Ling Chen
- Environmental and Precision Medicine Laboratory, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, Republic of China
- Department of Food Science, Tunghai University, Taichung, Taiwan, Republic of China
| | - Chung-Ho Chang
- PhD Program for Aging, China Medical University, Taichung, Taiwan, Republic of China
- Environmental and Precision Medicine Laboratory, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, Republic of China
- Institute of Cellular and System Medicine, National Health Research Institutes, Zhunan, Miaoli, Taiwan, Republic of China
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Fang S, Huang Y, Zhong S, Li Y, Zhang Y, Li Y, Sun J, Liu X, Wang Y, Zhang S, Xu T, Sun X, Gu P, Li D, Zhou H, Li B, Fan X. Regulation of Orbital Fibrosis and Adipogenesis by Pathogenic Th17 Cells in Graves Orbitopathy. J Clin Endocrinol Metab 2017; 102:4273-4283. [PMID: 28938397 DOI: 10.1210/jc.2017-01349] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 08/11/2017] [Indexed: 12/21/2022]
Abstract
CONTEXT T helper (Th)17 cells are correlated with many human autoimmune disorders, including Graves disease, and may play key roles in the pathogenesis of Graves orbitopathy (GO). OBJECTIVE To study the phenotype of Th17 cells in patients with GO and healthy subjects, investigate the fibrosis and adipogenesis in orbital fibroblasts (OFs) modulated by interleukin (IL)-17A, and determine the interaction between Th17 cells and OFs. DESIGN/SETTING/PARTICIPANTS Blood samples and orbital tissues from GO patients and healthy controls were collected. MAIN OUTCOME MEASURES We conducted multicolor flow cytometry, immunohistochemical and immunofluorescent stainings, Western blotting, a PathScan intracellular signaling assay, Luminex and enzyme-linked immunosorbent assays, and protein mass spectrum. RESULTS Interferon-γ- and IL-22-expressing Th17 cells are increased in GO patients, which are positively related to clinical activity score. Costimulatory molecules are highly expressed in GO orbits and most GO OFs are CD90+. IL-17A promotes TGF-β-induced fibrosis in CD90+ OFs but impedes 15-deoxy-Δ12,14-prostaglandin J2-induced adipogenesis in CD90- OFs. Th17 cells promote proinflammatory cytokine secretion in both CD90+ and CD90- OFs. Meanwhile, both CD90+ and CD90- OFs contribute to Th17 cell differentiation through prostaglandin E2 production, which can be attenuated by indomethacin. Furthermore, Th17 cells upregulate costimulatory molecule expression on OFs. CONCLUSION Our findings unravel the pathogenicity of IL-17A in the initiation and progression of GO. In-depth interpretation of the molecular basis of OFs delineated by CD90 and Th17-OF interaction will help to afford a novel approach to better therapeutic strategies for GO.
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Affiliation(s)
- Sijie Fang
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200011, China
- Shanghai Institute of Immunology, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
- Department of Immunology and Microbiology, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
| | - Yazhuo Huang
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200011, China
| | - Sisi Zhong
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200011, China
| | - Yangyang Li
- Shanghai Institute of Immunology, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
- Department of Immunology and Microbiology, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
| | - Yidan Zhang
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200011, China
| | - Yinwei Li
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200011, China
| | - Jing Sun
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200011, China
| | - Xingtong Liu
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200011, China
| | - Yang Wang
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200011, China
| | - Shuo Zhang
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200011, China
| | - Tianle Xu
- Discipline of Neuroscience, Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
| | - Xiaodong Sun
- Department of Ophthalmology, Shanghai First People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200080, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai 200080, China
| | - Ping Gu
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200011, China
| | - Dan Li
- Shanghai Institute of Immunology, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
- Department of Immunology and Microbiology, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
| | - Huifang Zhou
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200011, China
| | - Bin Li
- Shanghai Institute of Immunology, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
- Department of Immunology and Microbiology, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
| | - Xianqun Fan
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200011, China
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Abstract
The adipose tissue (AT) is multifunctional, acting as an endocrine tissue and participating in the regulation of the organism's homeostasis. Metabolic, endocrine and inflammatory mechanisms are tightly intertwined within the AT, regulating its function. Disruption of the equilibrium among these mechanisms leads to pathologies, the most common being obesity-related insulin resistance. Two types of AT exist, the white and the brown AT. Traditionally the white AT (WAT) was thought to store energy in the form of lipids, while the brown AT (BAT) was known to mediate heat generation. Recently, the 'brite' or 'beige' AT was identified, which is localized predominantly in subcutaneous WAT, but shares functional features with the BAT and is capable of heat production. The major stimulus triggering beige and brown adipogenesis is cold exposure and catecholamine signalling. However, several further signals and mechanisms exist, which can orchestrate and fine-tune beige and brown AT function. Immune cells and inflammation have emerged as regulators of beige and brown AT function. The present review will focus on the recently identified crosstalk between innate immunity and the regulation of beige and brown adipogenesis.
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Affiliation(s)
- Vasileia Ismini Alexaki
- Department of Clinical Pathobiochemistry, Medical Faculty, Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
| | - Triantafyllos Chavakis
- Department of Clinical Pathobiochemistry, Medical Faculty, Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine, TU Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
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Peng Z, Dong Z, Chang Q, Zhan W, Zeng Z, Zhang S, Lu F. Tissue engineering chamber promotes adipose tissue regeneration in adipose tissue engineering models through induced aseptic inflammation. Tissue Eng Part C Methods 2014; 20:875-85. [PMID: 24559078 DOI: 10.1089/ten.tec.2013.0431] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Tissue engineering chamber (TEC) makes it possible to generate significant amounts of mature, vascularized, stable, and transferable adipose tissue. However, little is known about the role of the chamber in tissue engineering. Therefore, to investigate the role of inflammatory response and the change in mechanotransduction started by TEC after implantation, we placed a unique TEC model on the surface of the groin fat pads in rats to study the expression of cytokines and tissue development in the TEC. The number of infiltrating cells was counted, and vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1) expression levels in the chamber at multiple time points postimplantation were analyzed by enzyme-linked immunosorbent assay. Tissue samples were collected at various time points and labeled for specific cell populations. The result showed that new adipose tissue formed in the chamber at day 60. Also, the expression of MCP-1 and VEGF in the chamber decreased slightly from an early stage as well as the number of the infiltrating cells. A large number of CD34+/perilipin- perivascular cells could be detected at day 30. Also, the CD34+/perilipin+ adipose precursor cell numbers increased sharply by day 45 and then decreased by day 60. CD34-/perilipin+ mature adipocytes were hard to detect in the chamber content at day 30, but their number increased and then peaked at day 60. Ki67-positive cells could be found near blood vessels and their number decreased sharply over time. Masson's trichrome showed that collagen was the dominant component of the chamber content at early stage and was replaced by newly formed small adipocytes over time. Our findings suggested that the TEC implantation could promote the proliferation of adipose precursor cells derived from local adipose tissue, increase angiogenesis, and finally lead to spontaneous adipogenesis by inducing aseptic inflammation and changing local mechanotransduction.
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Affiliation(s)
- Zhangsong Peng
- Department of Plastic and Cosmetic Surgery, Nanfang Hospital, Southern Medical University , Guang Zhou, P.R. China
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Vanella L, Kim DH, Sodhi K, Barbagallo I, Burgess AP, Falck JR, Schwartzman ML, Abraham NG. Crosstalk between EET and HO-1 downregulates Bach1 and adipogenic marker expression in mesenchymal stem cell derived adipocytes. Prostaglandins Other Lipid Mediat 2011; 96:54-62. [PMID: 21821145 DOI: 10.1016/j.prostaglandins.2011.07.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 07/14/2011] [Accepted: 07/19/2011] [Indexed: 01/10/2023]
Abstract
Epoxygenase activity and synthesis of epoxyeicosatrienoic acids (EETs) have emerged as important modulators of obesity and diabetes. We examined the effect of the EET-agonist 12-(3-hexylureido)dodec-8(2) enoic acid on mesenchymal stem cell (MSC) derived adipocytes proliferation and differentiation. MSCs expressed substantial levels of EETs and inhibition of soluble epoxide hydrolase (sEH) increased the level of EETs and decreased adipogenesis. EET agonist treatment increased HO-1 expression by inhibiting a negative regulator of HO-1 expression, Bach-1. EET treatment also increased βcatenin and pACC levels while decreasing PPARγ C/EBPα and fatty acid synthase levels. These changes were manifested by a decrease in the number of large inflammatory adipocytes, TNFα, IFNγ and IL-1α, but an increase in small adipocytes and in adiponectin levels. In summary, EET agonist treatment inhibits adipogenesis and decreases the levels of inflammatory cytokines suggesting the potential action of EETs as intracellular lipid signaling modulators of adipogenesis and adiponectin.
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Affiliation(s)
- Luca Vanella
- Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, OH 43614, USA.
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Abstract
PURPOSE OF REVIEW Obesity is associated with low-grade chronic inflammation in adipose tissue. This review presents an update on human and rodent studies analyzing the nature of fat-infiltrating immune cells, the time course of adipose tissue infiltration and underlying mechanisms. RECENT FINDINGS Intensive studies in rodents have shown that not only cells of the innate immune system traffic into adipose tissue but also various lymphocytes of the adaptive immunity are involved in inflammatory processes in fat. Several studies also provide insight in the order of appearance of macrophages and lymphocytes during the onset of obesity. Adipocytes and preadipocytes are also active players by their secretion of chemotactic adipokines. SUMMARY This review summarizes strong evidence for a link between the action of innate and adaptive immune systems in adipose tissue in the context of obesity and metabolism in rodents, but more studies in humans are necessary to relate this topic to human physiology. Targeting different immune cells at different stages of obesity may eventually lead to novel therapeutic approaches for the metabolic syndrome.
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Affiliation(s)
- Henrike Sell
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes-Center, Düsseldorf, Germany.
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Gustafson B, Hammarstedt A, Andersson CX, Smith U. Inflamed adipose tissue: a culprit underlying the metabolic syndrome and atherosclerosis. Arterioscler Thromb Vasc Biol 2007; 27:2276-83. [PMID: 17823366 DOI: 10.1161/atvbaha.107.147835] [Citation(s) in RCA: 307] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The metabolic syndrome is associated with a dysregulated adipose tissue; in part a consequence of adipose cell enlargement and the associated infiltration of macrophages. Adipose cell enlargement leads to a proinflammatory state in the cells with reduced secretion of adiponectin and with increased secretion of several cytokines and chemokines including interleukin (IL)-6, IL-8, and MCP-1. MCP-1 has been shown to play an important role for the associated recruitment of macrophages into the adipose tissue. The increased release of cytokines leads to an impaired differentiation of the preadipocytes with reduced lipid accumulation and induction of adiponectin, thus promoting ectopic lipid storage. In particular tumor necrosis factor (TNF) alpha, but also IL-6, has been shown to induce these effects in preadipocytes and this is associated with an increased Wnt signaling maintaining the cells in an undifferentiated and proinflammatory state. The proinflammatory state in the adipose tissue also leads to a local insulin resistance including an impaired inhibitory effect of insulin on FFA release. The insulin resistance further supports the proinflammatory state because insulin, by itself, is both antilipolytic and antiinflammatory by antagonizing cytokine-induced activation of STAT signaling.
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Affiliation(s)
- Birgit Gustafson
- The Lundberg Laboratory for Diabetes Research, Center of Excellence for Cardiovascular and Metabolic Research, Department of Molecular and Clinical Medicine, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden
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