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Hernandez-Resendiz I, Burkhardt R. Novel functions of Tribbles-homolog 1 in liver, adipocytes and atherosclerosis. Curr Opin Lipidol 2024; 35:51-57. [PMID: 38236937 DOI: 10.1097/mol.0000000000000917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
PURPOSE OF REVIEW Human genetics studies have sparked great interest in the pseudokinase Tribbles homolog 1, as variant at the TRIB1 gene locus were robustly linked to several cardiometabolic traits, including plasma lipids and coronary artery disease. In this review, we summarize recent findings from mouse models that investigated the function of hepatic and adipocyte Trib1 in lipid metabolism and its role in atherosclerosis. RECENT FINDINGS Studies in atherosclerosis prone low-density lipoprotein (LDL)-receptor knockout mice suggested that systemic Trib1 -deficiency promotes atherosclerotic lesion formation through the modulation of plasma lipids and inflammation. Further, investigations in mice with hepatocyte specific deletion of Trib1 identified a novel role in the catabolism of apoB-containing lipoproteins via regulation of the LDL-receptor. Moreover, recent studies on Trib1 in adipocytes uncovered critical functions in adipose tissue biology, including the regulation of plasma lipid and adiponectin levels and the response to β3-adrenergic receptor activation. SUMMARY Functional studies in mice have expanded our understanding of how Trib1 contributes to various aspects of cardiometabolic diseases. They support the notion that Trib1 exerts tissue-specific effects, which can result in opposing effects on cardiometabolic traits. Additional studies are required to fully elucidate the molecular mechanisms underlying the cellular and systemic effects of Trib1 .
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Affiliation(s)
- Ileana Hernandez-Resendiz
- Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, University of Regensburg, Germany
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Quiroz-Figueroa K, Vitali C, Conlon DM, Millar JS, Tobias JW, Bauer RC, Hand NJ, Rader DJ. TRIB1 regulates LDL metabolism through CEBPα-mediated effects on the LDL receptor in hepatocytes. J Clin Invest 2021; 131:146775. [PMID: 34779419 DOI: 10.1172/jci146775] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 09/21/2021] [Indexed: 12/20/2022] Open
Abstract
Genetic variants near the TRIB1 gene are highly significantly associated with plasma lipid traits and coronary artery disease. While TRIB1 is likely causal of these associations, the molecular mechanisms are not well understood. Here we sought to investigate how TRIB1 influences low density lipoprotein cholesterol (LDL-C) levels in mice. Hepatocyte-specific deletion of Trib1 (Trib1Δhep) in mice increased plasma cholesterol and apoB and slowed the catabolism of LDL-apoB due to decreased levels of LDL receptor (LDLR) mRNA and protein. Simultaneous deletion of the transcription factor CCAAT/enhancer-binding protein alpha (CEBPα) with TRIB1 eliminated the effects of TRIB1 on hepatic LDLR regulation and LDL catabolism. Using RNA-seq, we found that activating transcription factor 3 (Atf3) was highly upregulated in the livers of Trib1Δhep but not Trib1Δhep CebpaΔhep mice. ATF3 has been shown to directly bind to the CEBPα protein, and to repress the expression of LDLR by binding its promoter. Blunting the increase of ATF3 in Trib1Δhep mice reduced the levels of plasma cholesterol and partially attenuated the effects on LDLR. Based on these data, we conclude that deletion of Trib1 leads to a posttranslational increase in CEBPα, which increases ATF3 levels, thereby contributing to the downregulation of LDLR and increased plasma LDL-C.
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Affiliation(s)
| | - Cecilia Vitali
- Division of Translational Medicine and Human Genetics, Department of Medicine
| | - Donna M Conlon
- Division of Translational Medicine and Human Genetics, Department of Medicine
| | - John S Millar
- Division of Translational Medicine and Human Genetics, Department of Medicine
| | | | - Robert C Bauer
- Division of Translational Medicine and Human Genetics, Department of Medicine
| | - Nicholas J Hand
- Department of Genetics.,Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daniel J Rader
- Division of Translational Medicine and Human Genetics, Department of Medicine.,Department of Genetics.,Department of Pediatrics, and.,Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Xu Y, Li Y, Jadhav K, Pan X, Zhu Y, Hu S, Chen S, Chen L, Tang Y, Wang HH, Yang L, Wang DQH, Yin L, Zhang Y. Hepatocyte ATF3 protects against atherosclerosis by regulating HDL and bile acid metabolism. Nat Metab 2021; 3:59-74. [PMID: 33462514 PMCID: PMC7856821 DOI: 10.1038/s42255-020-00331-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 12/09/2020] [Indexed: 12/13/2022]
Abstract
Activating transcription factor (ATF)3 is known to have an anti-inflammatory function, yet the role of hepatic ATF3 in lipoprotein metabolism or atherosclerosis remains unknown. Here we show that overexpression of human ATF3 in hepatocytes reduces the development of atherosclerosis in Western-diet-fed Ldlr-/- or Apoe-/- mice, whereas hepatocyte-specific ablation of Atf3 has the opposite effect. We further show that hepatic ATF3 expression is inhibited by hydrocortisone. Mechanistically, hepatocyte ATF3 enhances high-density lipoprotein (HDL) uptake, inhibits intestinal fat and cholesterol absorption and promotes macrophage reverse cholesterol transport by inducing scavenger receptor group B type 1 (SR-BI) and repressing cholesterol 12α-hydroxylase (CYP8B1) in the liver through its interaction with p53 and hepatocyte nuclear factor 4α, respectively. Our data demonstrate that hepatocyte ATF3 is a key regulator of HDL and bile acid metabolism and atherosclerosis.
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Affiliation(s)
- Yanyong Xu
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Yuanyuan Li
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
- Zhongshan Institute for Drug Discovery, the Institutes of Drug Discovery and Development, Chinese Academy of Sciences, Zhongshan, China
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Kavita Jadhav
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Xiaoli Pan
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
- Divison of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yingdong Zhu
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Shuwei Hu
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Shaoru Chen
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Liuying Chen
- Divison of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yong Tang
- Department of Hepatobiliary Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Helen H Wang
- Department of Medicine and Genetics, Marion Bessin Liver Research Center and Albert Einstein College of Medicine, Bronx, NY, USA
| | - Ling Yang
- Divison of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - David Q-H Wang
- Department of Medicine and Genetics, Marion Bessin Liver Research Center and Albert Einstein College of Medicine, Bronx, NY, USA
| | - Liya Yin
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Yanqiao Zhang
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA.
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Gokulnath M, Partridge NC, Selvamurugan N. Runx2, a target gene for activating transcription factor-3 in human breast cancer cells. Tumour Biol 2014; 36:1923-31. [PMID: 25380580 DOI: 10.1007/s13277-014-2796-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 10/30/2014] [Indexed: 12/31/2022] Open
Abstract
Activating transcription factor (ATF-3) is a stress response gene and is induced by transforming growth factor beta 1 (TGF-β1) in breast cancer cells. In this study, we dissected the functional role of ATF-3 gene in vitro by knocking down its expression stably in human bone metastatic breast cancer cells (MDA-MB231). Knockdown of ATF-3 expression in these cells decreased cell number, altered cell cycle phase transition, and decreased mRNA expression of cell cycle genes. Knockdown of ATF-3 expression in MDA-MB231 cells also decreased cell migration, and the expression levels of invasive and metastatic genes such as MMP-13 and Runx2 were found to be decreased in these cells. Most importantly, ATF-3 was associated with Runx2 promoter in MDA-MB231 cells and knockdown of ATF-3 expression decreased its association with Runx2 promoter. Hence, our results suggested that ATF-3 plays a role in proliferation and invasion of bone metastatic breast cancer cells in vitro and we identified for the first time that Runx2 is a target gene of ATF-3 in MDA-MB231 cell line.
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Affiliation(s)
- M Gokulnath
- Department of Biotechnology, School of Bioengineering, SRM University, Kattankulathur, 603203, Tamil Nadu, India
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Wang CM, Brennan VC, Gutierrez NM, Wang X, Wang L, Yang WH. SUMOylation of ATF3 alters its transcriptional activity on regulation of TP53 gene. J Cell Biochem 2013; 114:589-98. [PMID: 22991139 DOI: 10.1002/jcb.24396] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 09/07/2012] [Indexed: 12/11/2022]
Abstract
Cyclic AMP-dependent transcription factor-3 (ATF3), a stress sensor, plays an essential role in cells to maintain homeostasis and has diverse functions in cellular survival and death signal pathways. ATF3 is a novel regulator of p53 protein stability and function. The activities of ATF3 are modulated by post-translational modifications (PTMs), such as ubiquitination, but whether it is modified by small ubiquitin-related modifier (SUMO) remains unknown. The aim of this study was to investigate whether ATF3 is post-translationally modified by SUMO proteins and also to elucidate SUMOylation of ATF3 on TP53 gene activity. Here we report that ATF3 is clearly defined as a SUMO target protein both in vitro SUMOylation assay using recombinant proteins and at the cellular levels. Furthermore, ATF3 interacted with UBE2I, the only SUMO E2 enzyme found so far. In addition, PIAS3β (a SUMO E3 ligase) enhanced and SENP2 and SENP7 (two SUMOylation proteases) decreased SUMOylation of ATF3, respectively. Finally, we found that ATF3 is selectively SUMOylated at lysine residue 42 but the SUMOylation does not alter subcellular localization of ATF3. We then characterized the functional role of ATF3 SUMOylation on TP53 gene expression. We found that SUMOylation of ATF3 is required for full repression of TP53 gene. Overall, we provide the first evidence that ATF3 is post-translationally modified by SUMO and SUMOylation of ATF3 plays a functional role in regulation of TP53 gene activity.
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Affiliation(s)
- Chiung-Min Wang
- Department of Biomedical Sciences, Mercer University School of Medicine, Savannah, GA 31404, USA
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