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Kothari V, Savard C, Tang J, Lee SP, Subramanian S, Wang S, den Hartigh LJ, Bornfeldt KE, Ioannou GN. sTREM2 is a plasma biomarker for human NASH and promotes hepatocyte lipid accumulation. Hepatol Commun 2023; 7:e0265. [PMID: 37820278 PMCID: PMC10578746 DOI: 10.1097/hc9.0000000000000265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 07/28/2023] [Indexed: 10/13/2023] Open
Abstract
BACKGROUND Pathogenetic mechanisms of the progression of NAFL to advanced NASH coupled with potential noninvasive biomarkers and novel therapeutic targets are active areas of investigation. The recent finding that increased plasma levels of a protein shed by myeloid cells -soluble Triggering Receptor Expressed on Myeloid cells 2 (sTREM2) -may be a biomarker for NASH has received much interest. We aimed to test sTREM2 as a biomarker for human NASH and investigate the role of sTREM2 in the pathogenesis of NASH. METHODS We conducted studies in both humans (comparing patients with NASH vs. NAFL) and in mice (comparing different mouse models of NASH) involving measurements of TREM2 gene and protein expression levels in the liver as well as circulating sTREM2 levels in plasma. We investigated the pathogenetic role of sTREM2 in hepatic steatosis using primary hepatocytes and bone marrow derived macrophages. RESULTS RNA sequencing analysis of livers from patients with NASH or NAFL as well as livers from 2 mouse models of NASH revealed elevated TREM2 expression in patients/mice with NASH as compared with NAFL. Plasma levels of sTREM2 were significantly higher in a well-characterized cohort of patients with biopsy-proven NASH versus NAFL (area under receiver-operating curve 0.807). Mechanistic studies revealed that cocultures of primary hepatocytes and macrophages with an impaired ability to shed sTREM2 resulted in reduced hepatocyte lipid droplet formation on palmitate stimulation, an effect that was counteracted by the addition of exogenous sTREM2 chimeric protein. Conversely, exogenous sTREM2 chimeric protein increased lipid droplet formation, triglyceride content, and expression of the lipid transporter CD36 in hepatocytes. Furthermore, inhibition of CD36 markedly attenuated sTREM2-induced lipid droplet formation in mouse primary hepatocytes. CONCLUSIONS Elevated levels of sTREM2 due to TREM2 shedding may directly contribute to the pathogenesis of NAFLD by promoting hepatocyte lipid accumulation, as well as serving as a biomarker for distinguishing patients with NASH versus NAFL. Further investigation of sTREM2 as a clinically useful diagnostic biomarker and of the therapeutic effects of targeting sTREM2 in NASH is warranted.
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Affiliation(s)
- Vishal Kothari
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, UW Medicine Diabetes Institute, University of Washington, Seattle, Washington, USA
| | - Christopher Savard
- Department of Medicine, Division of Gastroenterology, Veterans Affairs Puget Sound Health Care System, Seattle, Washington, USA
- Department of Medicine, Division of Gastroenterology, University of Washington, Seattle, Washington, USA
- Research and Development, Veterans Affairs Puget Sound Health Care System, Seattle, Washington, USA
| | - Jingjing Tang
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, UW Medicine Diabetes Institute, University of Washington, Seattle, Washington, USA
| | - Sum P. Lee
- Department of Medicine, Division of Gastroenterology, University of Washington, Seattle, Washington, USA
| | - Savitha Subramanian
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, UW Medicine Diabetes Institute, University of Washington, Seattle, Washington, USA
| | - Shari Wang
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, UW Medicine Diabetes Institute, University of Washington, Seattle, Washington, USA
| | - Laura J. den Hartigh
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, UW Medicine Diabetes Institute, University of Washington, Seattle, Washington, USA
| | - Karin E. Bornfeldt
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, UW Medicine Diabetes Institute, University of Washington, Seattle, Washington, USA
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - George N. Ioannou
- Department of Medicine, Division of Gastroenterology, Veterans Affairs Puget Sound Health Care System, Seattle, Washington, USA
- Department of Medicine, Division of Gastroenterology, University of Washington, Seattle, Washington, USA
- Research and Development, Veterans Affairs Puget Sound Health Care System, Seattle, Washington, USA
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Abstract
PURPOSE OF REVIEW Obesity is accompanied by atherogenic dyslipidemia, a specific lipid disorder characterized by both quantitative and qualitative changes of plasma lipoproteins. The main alterations in the lipid profile include hypertriglyceridemia, reduced high-density lipoprotein (HDL) cholesterol level, and elevated small dense low-density lipoprotein (LDL) particles. Epidemiological data show that obesity is more common in women and is a frequent risk factor for reproductive disorders, metabolic complications in pregnancy, and cardiometabolic disease later in life. The aim of this narrative review is to discuss recent advances in the research of dyslipidemia in obesity, with an emphasis on female-specific disorders and cardiometabolic risk. RECENT FINDINGS The focus of current research on dyslipidemia in obesity is moving toward structurally and functionally modified plasma lipoproteins. Special attention is paid to the pro-atherogenic role of triglyceride-rich lipoproteins and their remnants. Introduction of advanced analytical techniques enabled identification of novel lipid biomarkers with potential clinical applications. In particular, proteomic and lipidomic studies have provided significant progress in the comprehensive research of HDL's alterations in obesity. Obesity-related dyslipidemia is a widespread metabolic disturbance in polycystic ovary syndrome patients and high-risk pregnancies, but is seldom evaluated with respect to its impact on future cardiometabolic health. Obesity and associated cardiometabolic diseases require a more depth insight into the quality of lipoprotein particles. Further application of omics-based techniques would enable a more comprehensive evaluation of dyslipidemia in order to reduce an excessive cardiovascular risk attributable to increased body weight. However, more studies on obesity-related female reproductive disorders are needed for this approach to be adopted in daily clinical practice.
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Affiliation(s)
- Jelena Vekic
- Department of Medical Biochemistry, University of Belgrade-Faculty of Pharmacy, Vojvode Stepe 450, P. Box 146, 11000, Belgrade, Serbia.
| | - Aleksandra Stefanovic
- Department of Medical Biochemistry, University of Belgrade-Faculty of Pharmacy, Vojvode Stepe 450, P. Box 146, 11000, Belgrade, Serbia
| | - Aleksandra Zeljkovic
- Department of Medical Biochemistry, University of Belgrade-Faculty of Pharmacy, Vojvode Stepe 450, P. Box 146, 11000, Belgrade, Serbia
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den Hartigh LJ, May KS, Zhang XS, Chait A, Blaser MJ. Serum amyloid A and metabolic disease: evidence for a critical role in chronic inflammatory conditions. Front Cardiovasc Med 2023; 10:1197432. [PMID: 37396595 PMCID: PMC10311072 DOI: 10.3389/fcvm.2023.1197432] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 05/15/2023] [Indexed: 07/04/2023] Open
Abstract
Serum amyloid A (SAA) subtypes 1-3 are well-described acute phase reactants that are elevated in acute inflammatory conditions such as infection, tissue injury, and trauma, while SAA4 is constitutively expressed. SAA subtypes also have been implicated as playing roles in chronic metabolic diseases including obesity, diabetes, and cardiovascular disease, and possibly in autoimmune diseases such as systemic lupus erythematosis, rheumatoid arthritis, and inflammatory bowel disease. Distinctions between the expression kinetics of SAA in acute inflammatory responses and chronic disease states suggest the potential for differentiating SAA functions. Although circulating SAA levels can rise up to 1,000-fold during an acute inflammatory event, elevations are more modest (∼5-fold) in chronic metabolic conditions. The majority of acute-phase SAA derives from the liver, while in chronic inflammatory conditions SAA also derives from adipose tissue, the intestine, and elsewhere. In this review, roles for SAA subtypes in chronic metabolic disease states are contrasted to current knowledge about acute phase SAA. Investigations show distinct differences between SAA expression and function in human and animal models of metabolic disease, as well as sexual dimorphism of SAA subtype responses.
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Affiliation(s)
- Laura J. den Hartigh
- Department of Medicine, Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, WA, United States
- Diabetes Institute, University of Washington, Seattle, WA, United States
| | - Karolline S. May
- Department of Medicine, Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, WA, United States
- Diabetes Institute, University of Washington, Seattle, WA, United States
| | - Xue-Song Zhang
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, United States
| | - Alan Chait
- Department of Medicine, Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, WA, United States
- Diabetes Institute, University of Washington, Seattle, WA, United States
| | - Martin J. Blaser
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, United States
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Thomas SR, Zhang Y, Rye KA. The pleiotropic effects of high-density lipoproteins and apolipoprotein A-I. Best Pract Res Clin Endocrinol Metab 2022; 37:101689. [PMID: 36008277 DOI: 10.1016/j.beem.2022.101689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The high density lipoprotein (HDL) fraction of human plasma consists of multiple subpopulations of spherical particles that are structurally uniform, but heterogeneous in terms of size, composition and function. Numerous epidemiological studies have established that an elevated high density lipoprotein cholesterol (HDL-C) level is associated with decreased cardiovascular risk. However, with several recent randomised clinical trials of HDL-C raising agents failing to reduce cardiovascular events, contemporary research is transitioning towards clinical development of the cardioprotective functions of HDLs and the identification of functions that can be exploited for treatment of other diseases. This review describes the origins of HDLs and the causes of their compositional and functional heterogeneity. It then summarises current knowledge of how cardioprotective and other functions of HDLs are regulated. The final section of the review summarises recent advances in the clinical development of HDL-targeted therapies.
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Affiliation(s)
- Shane R Thomas
- Cardiometabolic Disease Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
| | - Yunjia Zhang
- Cardiometabolic Disease Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
| | - Kerry-Anne Rye
- Cardiometabolic Disease Research Group, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.
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Jin F, Li J, Guo J, Doeppner TR, Hermann DM, Yao G, Dai Y. Targeting epigenetic modifiers to reprogramme macrophages in non-resolving inflammation-driven atherosclerosis. EUROPEAN HEART JOURNAL OPEN 2021; 1:oeab022. [PMID: 35919269 PMCID: PMC9241575 DOI: 10.1093/ehjopen/oeab022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/28/2021] [Accepted: 08/14/2021] [Indexed: 12/14/2022]
Abstract
Epigenomic and epigenetic research has been providing several new insights into a variety of diseases caused by non-resolving inflammation, including cardiovascular diseases. Atherosclerosis (AS) has long been recognized as a chronic inflammatory disease of the arterial walls, characterized by local persistent and stepwise accelerating inflammation without resolution, also known as uncontrolled inflammation. The pathogenesis of AS is driven primarily by highly plastic macrophages via their polarization to pro- or anti-inflammatory phenotypes as well as other novel subtypes recently identified by single-cell sequencing. Although emerging evidence has indicated the key role of the epigenetic machinery in the regulation of macrophage plasticity, the investigation of epigenetic alterations and modifiers in AS and related inflammation is still in its infancy. An increasing number of the epigenetic modifiers (e.g. TET2, DNMT3A, HDAC3, HDAC9, JMJD3, KDM4A) have been identified in epigenetic remodelling of macrophages through DNA methylation or histone modifications (e.g. methylation, acetylation, and recently lactylation) in inflammation. These or many unexplored modifiers function to determine or switch the direction of macrophage polarization via transcriptional reprogramming of gene expression and intracellular metabolic rewiring upon microenvironmental cues, thereby representing a promising target for anti-inflammatory therapy in AS. Here, we review up-to-date findings involving the epigenetic regulation of macrophages to shed light on the mechanism of uncontrolled inflammation during AS onset and progression. We also discuss current challenges for developing an effective and safe anti-AS therapy that targets the epigenetic modifiers and propose a potential anti-inflammatory strategy that repolarizes macrophages from pro- to anti-inflammatory phenotypes.
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Affiliation(s)
- Fengyan Jin
- Department of Hematology, The First Hospital of Jilin University, 71 Xinmin Street, Changchun, Jilin 130012, China
| | - Jian Li
- The Key Laboratory of Geriatrics, Beijing Institute of Geriatrics, Beijing Hospital, National Center of Gerontology, National Health Commission, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, 1 Dong Dan Dahua Road, Dong Cheng District, Beijing 100730, China
| | - Jianfeng Guo
- School of Pharmaceutical Sciences, Jilin University, 1163 Xinmin Street, Changchun 130021, Jilin, China
| | - Thorsten R Doeppner
- Department of Neurology, University of Göttingen Medical School, Robert-Koch-Str. 40 37075, Göttingen, Germany
| | - Dirk M Hermann
- Department of Neurology, University Hospital Essen, Hufelandstr. 55, 45122 Essen, Germany
| | - Gang Yao
- Department of Neurology, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun, Jilin 130041, China
| | - Yun Dai
- Laboratory of Cancer Precision Medicine, Institute of Translational Medicine, The First Hospital of Jilin University, 519 Dong Min Zhu Street, Changchun, Jilin 130061, China
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