1
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Memetimin H, Zhu B, Lee S, Katz WS, Kern PA, Finlin BS. Improved β-cell function leads to improved glucose tolerance in a transgenic mouse expressing lipoprotein lipase in adipocytes. Sci Rep 2022; 12:22291. [PMID: 36566329 PMCID: PMC9789969 DOI: 10.1038/s41598-022-26995-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 12/22/2022] [Indexed: 12/25/2022] Open
Abstract
Lipoprotein lipase (LPL) hydrolyzes the triglyceride core of lipoproteins and also functions as a bridge, allowing for lipoprotein and cholesterol uptake. Transgenic mice expressing LPL in adipose tissue under the control of the adiponectin promoter (AdipoQ-LPL) have improved glucose metabolism when challenged with a high fat diet. Here, we studied the transcriptional response of the adipose tissue of these mice to acute high fat diet exposure. Gene set enrichment analysis (GSEA) provided mechanistic insight into the improved metabolic phenotype of AdipoQ-LPL mice. First, the cholesterol homeostasis pathway, which is controlled by the SREBP2 transcription factor, is repressed in gonadal adipose tissue AdipoQ-LPL mice. Furthermore, we identified SND1 as a link between SREBP2 and CCL19, an inflammatory chemokine that is reduced in AdipoQ-LPL mice. Second, GSEA identified a signature for pancreatic β-cells in adipose tissue of AdipoQ-LPL mice, an unexpected finding. We explored whether β-cell function is improved in AdipoQ-LPL mice and found that the first phase of insulin secretion is increased in mice challenged with high fat diet. In summary, we identify two different mechanisms for the improved metabolic phenotype of AdipoQ-LPL mice. One involves improved adipose tissue function and the other involves adipose tissue-pancreatic β-cell crosstalk.
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Affiliation(s)
- Hasiyet Memetimin
- grid.266539.d0000 0004 1936 8438Division of Endocrinology, and the Barnstable Brown Diabetes and Obesity Center, Department of Medicine, University of Kentucky, Lexington, KY USA
| | - Beibei Zhu
- grid.266539.d0000 0004 1936 8438Division of Endocrinology, and the Barnstable Brown Diabetes and Obesity Center, Department of Medicine, University of Kentucky, Lexington, KY USA
| | - Sangderk Lee
- grid.266539.d0000 0004 1936 8438Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY USA
| | - Wendy S. Katz
- grid.266539.d0000 0004 1936 8438Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY USA
| | - Philip A. Kern
- grid.266539.d0000 0004 1936 8438Division of Endocrinology, and the Barnstable Brown Diabetes and Obesity Center, Department of Medicine, University of Kentucky, Lexington, KY USA
| | - Brian S. Finlin
- grid.266539.d0000 0004 1936 8438Division of Endocrinology, and the Barnstable Brown Diabetes and Obesity Center, Department of Medicine, University of Kentucky, Lexington, KY USA
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2
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Zhao C, Cui X, Zhao Y, Qian B, Zhang N, Xin L, Ha C, Yang J, Wang X, Gao X. Impact of hepatocyte-specific deletion of staphylococcal nuclease and tudor domain containing 1 (SND1) on liver insulin resistance and acute liver failure of mice. Bioengineered 2021; 12:7360-7375. [PMID: 34608846 PMCID: PMC8806720 DOI: 10.1080/21655979.2021.1974653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Although our previous research shows an ameliorated high-fat diet (HFD)-induced hepatic steatosis and insulin resistance in global SND1 transgenic mice, the involvement of SND1 loss-of-function in hepatic metabolism remains elusive. Herein, we aim to explore the potential impact of hepatocyte-specific SND1 deletion on insulin-resistant mice. As SND1 is reported to be linked to inflammatory response, the pathobiological feature of acute liver failure (ALF) is also investigated. Hence, we construct the conditional liver knockout (LKO) mice of SND1 for the first time. Under the condition of HFD, the absence of hepatic SND1 affects the weight of white adipose tissue, but not the gross morphology, body weight, cholesterol level, liver weight, and hepatic steatosis of mice. Furthermore, we fail to observe significant differences in either HFD-induced insulin resistance or lipopolysaccharide/D-galactosamine-induced (LPS/D-GaIN) ALF between LKO and wild type (WT) mice in terms of inflammation and tissue damage. Compared with negative controls, there is no differential SND1 expression in various species of sample with insulin resistance or ALF, based on several gene expression omnibus datasets, including GSE23343, GSE160646, GSE120243, GSE48794, GSE13271, GSE151268, GSE62026, GSE120652, and GSE38941. Enrichment result of SND1-binding partners or related genes indicates a sequence of issues related to RNA or lipid metabolism, but not glucose homeostasis or hepatic failure. Overall, hepatic SND1 is insufficient to alter the phenotypes of hepatic insulin resistance and acute liver failure in mice. The SND1 in various organs is likely to cooperate in regulating glucose homeostasis by affecting the expression of lipid metabolism-related RNA transcripts during stress.
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Affiliation(s)
- Chunyan Zhao
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
| | - Xiaoteng Cui
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China.,Laboratory of Neuro-Oncology, Tianjin Neurological Institute, Department of Neurosurgery, Tianjin Medical University General Hospital and Key Laboratory of Neurotrauma, Variation, and Regeneration, Ministry of Education and Tianjin Municipal Government, Tianjin, China
| | - Yan Zhao
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
| | - Baoxin Qian
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China.,Department of Gastroenterology and Hepatology, The Third Central Clinical College of Tianjin Medical University, Tianjin Third Central Hospital, Tianjin, China
| | - Nan Zhang
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
| | - Lingbiao Xin
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
| | - Chuanbo Ha
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
| | - Jie Yang
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
| | - Xinting Wang
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
| | - Xingjie Gao
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
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3
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Abstract
Arginine methylation is an essential post-translational modification (PTM) deposited by protein arginine methyltransferases (PRMTs) and recognized by Tudor domain-containing proteins. Of the nine mammalian PRMTs, PRMT5 is the primary enzyme responsible for the deposition of symmetric arginine methylation marks in cells. The staphylococcal nuclease and Tudor domain-containing 1 (SND1) effector protein is a key reader of the marks deposited by PRMT5. Both PRMT5 and SND1 are broadly expressed and their deregulation is reported to be associated with a range of disease phenotypes, including cancer. Hepatocellular carcinoma (HCC) is an example of a cancer type that often displays elevated PRMT5 and SND1 levels, and there is evidence that hyperactivation of this axis is oncogenic. Importantly, this pathway can be tempered with small-molecule inhibitors that target PRMT5, offering a therapeutic node for cancer, such as HCC, that display high PRMT5–SND1 axis activity. Here we summarize the known activities of this writer–reader pair, with a focus on their biological roles in HCC. This will help establish a foundation for treating HCC with PRMT5 inhibitors and also identify potential biomarkers that could predict sensitivity to this type of therapy.
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Affiliation(s)
- Tanner Wright
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; (T.W.); (Y.W.)
- Graduate Program in Genetics & Epigenetics, UTHealth Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Yalong Wang
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; (T.W.); (Y.W.)
| | - Mark T. Bedford
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; (T.W.); (Y.W.)
- Correspondence:
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4
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Navarro-Imaz H, Ochoa B, García-Arcos I, Martínez MJ, Chico Y, Fresnedo O, Rueda Y. Molecular and cellular insights into the role of SND1 in lipid metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158589. [DOI: 10.1016/j.bbalip.2019.158589] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/20/2019] [Accepted: 12/11/2019] [Indexed: 12/11/2022]
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5
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Ochoa B, Chico Y, Martínez MJ. Insights Into SND1 Oncogene Promoter Regulation. Front Oncol 2018; 8:606. [PMID: 30619748 PMCID: PMC6297716 DOI: 10.3389/fonc.2018.00606] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 11/27/2018] [Indexed: 01/09/2023] Open
Abstract
The staphylococcal nuclease and Tudor domain containing 1 gene (SND1), also known as Tudor-SN, TSN or p100, encodes an evolutionarily conserved protein with invariant domain composition. SND1 contains four repeated staphylococcal nuclease domains and a single Tudor domain, which confer it endonuclease activity and extraordinary capacity for interacting with nucleic acids, individual proteins and protein complexes. Originally described as a transcriptional coactivator, SND1 plays fundamental roles in the regulation of gene expression, including RNA splicing, interference, stability, and editing, as well as in the regulation of protein and lipid homeostasis. Recently, SND1 has gained attention as a potential disease biomarker due to its positive correlation with cancer progression and metastatic spread. Such functional diversity of SND1 marks this gene as interesting for further analysis in relation with the multiple levels of regulation of SND1 protein production. In this review, we summarize the SND1 genomic region and promoter architecture, the set of transcription factors that can bind the proximal promoter, and the evidence supporting transactivation of SND1 promoter by a number of signal transduction pathways operating in different cell types and conditions. Unraveling the mechanisms responsible for SND1 promoter regulation is of utmost interest to decipher the SND1 contribution in the realm of both normal and abnormal physiology.
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Affiliation(s)
| | | | - María José Martínez
- Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
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6
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Wang X, Xin L, Duan Z, Zuo Z, Wang Y, Ren Y, Zhang W, Sun X, Liu X, Ge L, Yang X, Yao Z, Yang J. Global Tudor-SN transgenic mice are protected from obesity-induced hepatic steatosis and insulin resistance. FASEB J 2018; 33:3731-3745. [PMID: 30521378 DOI: 10.1096/fj.201801253rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In the current study, we explored the impact of Tudor-staphylococcal nuclease (SN) on obesity induced by a high-fat diet (HFD) in mice, because the functional involvement of Tudor-SN in lipid metabolism in vivo is unknown. HFD-transgenic (Tg) mice exhibited reductions in hepatic steatosis and systemic insulin resistance. There was no difference in hepatic lipid accumulation between chow-fed wild-type (WT) and chow-fed Tg mice; consistently, no difference in activation of the lipogenic pathway was detected. Overactivation of hepatic nuclear sterol regulatory element-binding protein (nSrebp2)-2, the central regulator of cholesterol metabolic proteins, was observed in HFD-Tg livers along with improved cholesterol homeostasis, but no such changes were observed in HFD-WT livers. Consistent results were observed in vitro in α-mouse liver 12 cells treated with palmitate mimicking the HFD state. In addition, global gene analysis indicated that various downstream targets of nSrebp2, were up-regulated in HFD-Tg livers. Moreover, HFD-WT mice displayed islet hypertrophy and suppression of glucose-induced insulin secretion from islets, whereas HFD-Tg mice had normal pancreatic islets. This finding suggests that the improved pancreatic metabolism of HFD-Tg mice is related to the systemic effect of insulin resistance, not to the autonomous influence of pancreatic cells. Tudor-SN is likely to be a key regulator for ameliorating HFD-induced hepatic steatosis and systemic insulin resistance in vivo.-Wang, X., Xin, L., Duan, Z., Zuo, Z., Wang, Y., Ren, Y., Zhang, W., Sun, X., Liu, X., Ge, L., Yang, X., Yao, Z., Yang, J. Global Tudor-SN transgenic mice are protected from obesity-induced hepatic steatosis and insulin resistance.
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Affiliation(s)
- Xinting Wang
- Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, and Tianjin Medical University, Tianjin, China.,Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Lingbiao Xin
- Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, and Tianjin Medical University, Tianjin, China.,Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Zhongchao Duan
- Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, and Tianjin Medical University, Tianjin, China.,Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Zhiyu Zuo
- Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, and Tianjin Medical University, Tianjin, China.,Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Yuan Wang
- Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, and Tianjin Medical University, Tianjin, China.,Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Yuanyuan Ren
- Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, and Tianjin Medical University, Tianjin, China.,Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Wei Zhang
- Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, and Tianjin Medical University, Tianjin, China.,Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Xiaoming Sun
- Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, and Tianjin Medical University, Tianjin, China.,Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Xin Liu
- Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, and Tianjin Medical University, Tianjin, China.,Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Lin Ge
- Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, and Tianjin Medical University, Tianjin, China.,Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Xi Yang
- Department of Immunology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Zhi Yao
- Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, and Tianjin Medical University, Tianjin, China.,Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Jie Yang
- Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin Medical University, Tianjin, China.,Department of Biochemistry and Molecular Biology, and Tianjin Medical University, Tianjin, China.,Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
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7
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Navarro-Imaz H, Chico Y, Rueda Y, Fresnedo O. Channeling of newly synthesized fatty acids to cholesterol esterification limits triglyceride synthesis in SND1-overexpressing hepatoma cells. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:137-146. [PMID: 30448348 DOI: 10.1016/j.bbalip.2018.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 10/11/2018] [Accepted: 11/11/2018] [Indexed: 12/15/2022]
Abstract
SND1 is a putative oncoprotein whose molecular function remains unclear. Its overexpression in hepatocellular carcinoma impairs cholesterol homeostasis due to the altered activation of the sterol regulatory element-binding protein (SREBP) 2, which results in the accumulation of cellular cholesteryl esters (CE). In this work, we explored whether high cholesterol synthesis and esterification originates changes in glycerolipid metabolism that might affect cell growth, given that acetyl-coenzyme A is required for cholesterogenesis and fatty acids (FA) are the substrates of acyl-coenzyme A:cholesterol acyltransferase (ACAT). SND1-overexpressing hepatoma cells show low triglyceride (TG) synthesis, but phospholipid biosynthesis or cell growth is not affected. Limited TG synthesis is not due to low acetyl-coenzyme A or NADPH availability. We demonstrate that the main factor limiting TG synthesis is the utilization of FAs for cholesterol esterification. These metabolic adaptations are linked to high Scd1 expression, needed for the de novo production of oleic acid, the main FA used by ACAT. We conclude that high cholesterogenesis due to SND1 overexpression might determine the channeling of FAs to CEs.
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Affiliation(s)
- Hiart Navarro-Imaz
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, B° Sarriena s/n, 48940 Leioa, Spain.
| | - Yolanda Chico
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, B° Sarriena s/n, 48940 Leioa, Spain.
| | - Yuri Rueda
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, B° Sarriena s/n, 48940 Leioa, Spain.
| | - Olatz Fresnedo
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, B° Sarriena s/n, 48940 Leioa, Spain.
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8
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Arisqueta L, Navarro-Imaz H, Labiano I, Rueda Y, Fresnedo O. High-fat diet overfeeding promotes nondetrimental liver steatosis in female mice. Am J Physiol Gastrointest Liver Physiol 2018; 315:G772-G780. [PMID: 30095299 DOI: 10.1152/ajpgi.00022.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
High-fat diet (HFD) feeding or leptin-deficient mice are extensively used as models resembling features of human nonalcoholic fatty liver disease (NAFLD). The concurrence of experimental factors as fat content and source or total caloric intake leads to prominent differences in the development of the hepatic steatosis and related disturbances. In this work, we characterized the hepatic lipid accumulation induced by HFD in wild-type (WT) and ob/ ob mice with the purpose of differentiating adaptations to HFD from those specific of increased overfeeding due to leptin deficiency-associated hyperphagia. Given that most published works have been done in male models, we used female mice with the aim of increasing the body of evidence regarding NAFLD in female subjects. HFD promoted liver lipid accumulation only in the hyperphagic strain. Nevertheless, a decrease of lipid droplet-associated cholesteryl ester (CE) in both WT and obese animals was observed. These changes were accompanied by an improvement in the profile of lipoproteins that transport cholesterol and liver function markers in plasma from ob/ ob mice and a lower hepatic index. Using primary hepatocytes from female mice, overaccumulation of CE induced by 0.4 mM oleic acid reversed in the presence of a specific Takeda G protein-coupled bile acid receptor agonist. Nevertheless, hepatocytes from male mice were not responsive. This study suggests that enterohepatic circulation of bile acids might be one of the factors that can affect sex dimorphism in NAFLD development, which underlines the importance of including female models in the NAFLD research field. NEW & NOTEWORTHY This work provides new insight into the use of high-fat diet as a model to induce nonalcoholic fatty liver disease in wild-type and ob/ ob female mice. We show that high-fat diet induces steatosis only in ob/ ob mice while, surprisingly, several health indicators improve. Noteworthy, experiments with primary hepatocytes from male and female mice show that they express Takeda G protein-coupled bile acid receptor and that it and bile acid enterohepatic circulation might be accountable for sex dimorphism in nonalcoholic fatty liver disease development.
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Affiliation(s)
- Lino Arisqueta
- Facultad de Ciencias Naturales y Ambientales, Universidad Internacional SEK , Quito , Ecuador
| | - Hiart Navarro-Imaz
- Lipids and Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Ibone Labiano
- Department of Liver and Gastrointestinal Diseases, Health Research Institute, Biodonostia, Spain
| | - Yuri Rueda
- Lipids and Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Olatz Fresnedo
- Lipids and Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
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9
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Xu JL, Gan XX, Ni J, Shao DC, Shen Y, Miao NJ, Xu D, Zhou L, Zhang W, Lu LM. SND p102 promotes extracellular matrix accumulation and cell proliferation in rat glomerular mesangial cells via the AT1R/ERK/Smad3 pathway. Acta Pharmacol Sin 2018; 39:1513-1521. [PMID: 30150789 DOI: 10.1038/aps.2017.184] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 12/14/2017] [Indexed: 02/06/2023] Open
Abstract
SND p102 was first described as a transcriptional co-activator, and subsequently determined to be a co-regulator of Pim-1, STAT6 and STAT5. We previously reported that SND p102 expression was increased in high glucose-treated mesangial cells (MCs) and plays a role in the extracellular matrix (ECM) accumulation of MCs by regulating the activation of RAS. In this study, we further examined the roles of SND p102 in diabetic nephropathy (DN)-induced glomerulosclerosis. Rats were injected with STZ (50 mg/kg, ip) to induce diabetes. MCs or isolated glomeruli were cultured in normal glucose (NG, 5.5 mmol/L)- or high glucose (HG, 25 mmol/L)-containing DMEM. We found that SND p102 expression was significantly increased in the diabetic kidneys, as well as in HG-treated isolated glomeruli and MCs. In addition, HG treatment induced significant fibrotic changes in MCs evidenced by enhanced protein expression of TGF-β, fbronectin and collagen IV, and significantly increased the proliferation of MCs. We further revealed that overexpression of SND p102 significantly increased the protein expression of angiotensin II (Ang II) type 1 receptor (AT1R) in MCs by increasing its mRNA levels via directly targeting the AT1R 3'-UTR, which resulted in activation of the ERK/Smad3 signaling and subsequently promoted the up-regulation of fbronectin, collagen IV, and TGF-β in MCs, as well as the cell proliferation. These results demonstrate that SND p102 is a key regulator of AT1R-mediating ECM synthesis and cell proliferation in MCs. Thus, small molecule inhibitors of SND p102 may be a novel therapeutic strategy for DN.
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10
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Chidambaranathan-Reghupaty S, Mendoza R, Fisher PB, Sarkar D. The multifaceted oncogene SND1 in cancer: focus on hepatocellular carcinoma. ACTA ACUST UNITED AC 2018; 4. [PMID: 32258418 PMCID: PMC7117101 DOI: 10.20517/2394-5079.2018.34] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Staphylococcal nuclease and tudor domain containing 1 (SND1) is a protein that regulates a complex array of functions. It controls gene expression through transcriptional activation, mRNA degradation, mRNA stabilization, ubiquitination and alternative splicing. More than two decades of research has accumulated evidence of the role of SND1 as an oncogene in various cancers. It is a promoter of cancer hallmarks like proliferation, invasion, migration, angiogenesis and metastasis. In addition to these functions, it has a role in lipid metabolism, inflammation and stress response. The participation of SND1 in such varied functions makes it distinct from most oncogenes that are relatively more focused in their role. This becomes important in the case of hepatocellular carcinoma (HCC) since in addition to typical cancer drivers, factors like lipid metabolism deregulation and chronic inflammation can predispose hepatocytes to HCC. The objective of this review is to provide a summary of the current knowledge available on SND1, specifically in relation to HCC and to shed light on its prospect as a therapeutic target.
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Affiliation(s)
| | - Rachel Mendoza
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Paul B Fisher
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA.,Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA.,VCU Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Devanand Sarkar
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA.,Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA.,VCU Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
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11
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Hu ZB, Ma KL, Zhang Y, Wang GH, Liu L, Lu J, Chen PP, Lu CC, Liu BC. Inflammation-activated CXCL16 pathway contributes to tubulointerstitial injury in mouse diabetic nephropathy. Acta Pharmacol Sin 2018; 39:1022-1033. [PMID: 29620052 DOI: 10.1038/aps.2017.177] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/19/2017] [Indexed: 02/06/2023] Open
Abstract
Inflammation and lipid disorders play crucial roles in synergistically accelerating the progression of diabetic nephropathy (DN). In this study we investigated how inflammation and lipid disorders caused tubulointerstitial injury in DN in vivo and in vitro. Diabetic db/db mice were injected with 10% casein (0.5 mL, sc) every other day for 8 weeks to cause chronic inflammation. Compared with db/db mice, casein-injected db/db mice showed exacerbated tubulointerstitial injury, evidenced by increased secretion of extracellular matrix (ECM) and cholesterol accumulation in tubulointerstitium, which was accompanied by activation of the CXC chemokine ligand 16 (CXCL16) pathway. In the in vitro study, we treated HK-2 cells with IL-1β (5 ng/mL) and high glucose (30 mmol/L). IL-1β treatment increased cholesterol accumulation in HK-2 cells, leading to greatly increased ROS production, ECM protein expression levels, which was accompanied by the upregulated expression levels of proteins in the CXCL16 pathway. In contrast, after CXCL16 in HK-2 cells was knocked down by siRNA, the IL-1β-deteriorated changes were attenuated. In conclusion, inflammation accelerates renal tubulointerstitial lesions in mouse DN via increasing the activity of CXCL16 pathway.
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12
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Armengol S, Arretxe E, Enzunza L, Llorente I, Mendibil U, Navarro-Imaz H, Ochoa B, Chico Y, Martínez MJ. SREBP-2-driven transcriptional activation of human SND1 oncogene. Oncotarget 2017; 8:108181-108194. [PMID: 29296233 PMCID: PMC5746135 DOI: 10.18632/oncotarget.22569] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 09/22/2017] [Indexed: 01/28/2023] Open
Abstract
Upregulation of Staphylococcal nuclease and tudor domain containing 1 (SND1) is linked to cancer progression and metastatic spread. Increasing evidence indicates that SND1 plays a role in lipid homeostasis. Recently, it has been shown that SND1-overexpressing hepatocellular carcinoma cells present an increased de novo cholesterol synthesis and cholesteryl ester accumulation. Here we reveal that SND1 oncogene is a novel target for SREBPs. Exposure of HepG2 cells to the cholesterol-lowering drug simvastatin or to a lipoprotein-deficient medium triggers SREBP-2 activation and increases SND1 promoter activity and transcript levels. Similar increases in SND1 promoter activity and mRNA are mimicked by overexpressing nuclear SREBP-2 through expression vector transfection. Conversely, SREBP-2 suppression with specific siRNA or the addition of cholesterol/25-hydroxycholesterol to cell culture medium reduces transcriptional activity of SND1 promoter and SND1 mRNA abundance. Chromatin immunoprecipitation assays and site-directed mutagenesis show that SREBP-2 binds to the SND1 proximal promoter in a region containing one SRE and one E-box motif which are critical for maximal transcriptional activity under basal conditions. SREBP-1, in contrast, binds exclusively to the SRE element. Remarkably, while ectopic expression of SREBP-1c or -1a reduces SND1 promoter activity, knocking-down of SREBP-1 enhances SND1 mRNA and protein levels but failed to affect SND1 promoter activity. These findings reveal that SREBP-2 and SREBP-1 bind to specific sites in SND1 promoter and regulate SND1 transcription in opposite ways; it is induced by SREBP-2 activating conditions and repressed by SREBP-1 overexpression. We anticipate the contribution of a SREBPs/SND1 pathway to lipid metabolism reprogramming of human hepatoma cells.
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Affiliation(s)
- Sandra Armengol
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, 48940 Leioa, Vizcaya, Spain
| | - Enara Arretxe
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, 48940 Leioa, Vizcaya, Spain
| | - Leire Enzunza
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, 48940 Leioa, Vizcaya, Spain
| | - Irati Llorente
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, 48940 Leioa, Vizcaya, Spain
| | - Unai Mendibil
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, 48940 Leioa, Vizcaya, Spain
| | - Hiart Navarro-Imaz
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, 48940 Leioa, Vizcaya, Spain
| | - Begoña Ochoa
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, 48940 Leioa, Vizcaya, Spain
| | - Yolanda Chico
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, 48940 Leioa, Vizcaya, Spain
| | - María José Martínez
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, 48940 Leioa, Vizcaya, Spain
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13
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Navarro-Imaz H, Rueda Y, Fresnedo O. SND1 overexpression deregulates cholesterol homeostasis in hepatocellular carcinoma. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:988-996. [DOI: 10.1016/j.bbalip.2016.05.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 05/18/2016] [Accepted: 05/24/2016] [Indexed: 01/06/2023]
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14
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Fernández R, Carriel V, Lage S, Garate J, Díez-García J, Ochoa B, Castro B, Alaminos M, Fernández JA. Deciphering the Lipid Architecture of the Rat Sciatic Nerve Using Imaging Mass Spectrometry. ACS Chem Neurosci 2016; 7:624-32. [PMID: 27043994 DOI: 10.1021/acschemneuro.6b00010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Knowledge on the normal structure and molecular composition of the peripheral nerves is essential to understand their pathophysiology and to select the regeneration strategies after injury. However, the precise lipid composition of the normal peripheral nerve is still poorly known. Here, we present the first study of distribution of individual lipids in the mature sciatic nerve of rats by imaging mass spectrometry. Both positive and negative ion modes were used to detect, identify and in situ map 166 molecular species of mainly glycerophospholipids, sphingomyelins, sulfatides, and diacyl and triacylglycerols. In parallel, lipid extracts were analyzed by LC-MS/MS to verify and complement the identification of lipids directly from the whole tissue. Three anatomical regions were clearly identified by its differential lipid composition: the nerve fibers, the connective tissue and the adipose tissue that surrounds the nerve. Unexpectedly, very little variety of phosphatidylcholine (PC) species was found, being by far PC 34:1 the most abundant species. Also, a rich composition on sulfatides was detected in fibers, probably due to the important role they play in the myelin cover around axons, as well as an abundance of storage lipids in the adipose and connective tissues. The database of lipids here presented for each region and for the whole sciatic nerve is a first step toward understanding the variety of the peripheral nerves' lipidome and its changes associated with different diseases and mechanical injuries.
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Affiliation(s)
| | - Víctor Carriel
- Tissue
Engineering Group, Department of Histology, Faculty of Medicine, University of Granada, 18012 Granada, Spain
| | | | | | | | | | - Begoña Castro
- Histocell, S.L., Bizkaia Technology Park 800, 48160 Derio, Spain
| | - Miguel Alaminos
- Tissue
Engineering Group, Department of Histology, Faculty of Medicine, University of Granada, 18012 Granada, Spain
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15
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Arretxe E, Armengol S, Mula S, Chico Y, Ochoa B, Martínez MJ. Profiling of promoter occupancy by the SND1 transcriptional coactivator identifies downstream glycerolipid metabolic genes involved in TNFα response in human hepatoma cells. Nucleic Acids Res 2015; 43:10673-88. [PMID: 26323317 PMCID: PMC4678849 DOI: 10.1093/nar/gkv858] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 08/17/2015] [Indexed: 01/07/2023] Open
Abstract
The NF-κB-inducible Staphylococcal nuclease and tudor domain-containing 1 gene (SND1) encodes a coactivator involved in inflammatory responses and tumorigenesis. While SND1 is known to interact with certain transcription factors and activate client gene expression, no comprehensive mapping of SND1 target genes has been reported. Here, we have approached this question by performing ChIP-chip assays on human hepatoma HepG2 cells and analyzing SND1 binding modulation by proinflammatory TNFα. We show that SND1 binds 645 gene promoters in control cells and 281 additional genes in TNFα-treated cells. Transcription factor binding site analysis of bound probes identified motifs for established partners and for novel transcription factors including HSF, ATF, STAT3, MEIS1/AHOXA9, E2F and p300/CREB. Major target genes were involved in gene expression and RNA metabolism regulation, as well as development and cellular metabolism. We confirmed SND1 binding to 21 previously unrecognized genes, including a set of glycerolipid genes. Knocking-down experiments revealed that SND1 deficiency compromises the glycerolipid gene reprogramming and lipid phenotypic responses to TNFα. Overall, our findings uncover an unexpected large set of potential SND1 target genes and partners and reveal SND1 to be a determinant downstream effector of TNFα that contributes to support glycerophospholipid homeostasis in human hepatocellular carcinoma during inflammation.
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Affiliation(s)
- Enara Arretxe
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), 48940 Leioa, Bizkaia, Spain
| | - Sandra Armengol
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), 48940 Leioa, Bizkaia, Spain
| | - Sarai Mula
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), 48940 Leioa, Bizkaia, Spain
| | - Yolanda Chico
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), 48940 Leioa, Bizkaia, Spain
| | - Begoña Ochoa
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), 48940 Leioa, Bizkaia, Spain
| | - María José Martínez
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), 48940 Leioa, Bizkaia, Spain
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16
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Arisqueta L, Navarro-Imaz H, Rueda Y, Fresnedo O. Cholesterol mobilization from hepatic lipid droplets during endotoxemia is altered in obese ob/ob mice. J Biochem 2015; 158:321-9. [DOI: 10.1093/jb/mvv047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 03/31/2015] [Indexed: 11/12/2022] Open
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17
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Armengol S, Arretxe E, Enzunza L, Mula S, Ochoa B, Chico Y, Martínez MJ. The promoter of cell growth- and RNA protection-associated SND1 gene is activated by endoplasmic reticulum stress in human hepatoma cells. BMC BIOCHEMISTRY 2014; 15:25. [PMID: 25494629 PMCID: PMC4266219 DOI: 10.1186/s12858-014-0025-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 11/26/2014] [Indexed: 12/15/2022]
Abstract
Background Staphyloccocal nuclease domain-containing protein 1 (SND1) is involved in the regulation of gene expression and RNA protection. While numerous studies have established that SND1 protein expression is modulated by cellular stresses associated with tumor growth, hypoxia, inflammation, heat-shock and oxidative conditions, little is known about the factors responsible for SND1 expression. Here, we have approached this question by analyzing the transcriptional response of human SND1 gene to pharmacological endoplasmic reticulum (ER) stress in liver cancer cells. Results We provide first evidence that SND1 promoter activity is increased in human liver cancer cells upon exposure to thapsigargin or tunicamycin or by ectopic expression of ATF6, a crucial transcription factor in the unfolded protein response triggered by ER stress. Deletion analysis of the 5’-flanking region of SND1 promoter identified maximal activation in fragment (-934, +221), which contains most of the predicted ER stress response elements in proximal promoter. Quantitative real-time PCR revealed a near 3 fold increase in SND1 mRNA expression by either of the stress-inducers; whereas SND1 protein was maximally upregulated (3.4-fold) in cells exposed to tunicamycin, a protein glycosylation inhibitor. Conclusion Promoter activity of the cell growth- and RNA-protection associated SND1 gene is up-regulated by ER stress in human hepatoma cells.
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Affiliation(s)
| | | | | | | | | | | | - María José Martínez
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, Leioa, 48940, Spain.
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18
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Milochau A, Lagrée V, Benassy MN, Chaignepain S, Papin J, Garcia-Arcos I, Lajoix A, Monterrat C, Coudert L, Schmitter JM, Ochoa B, Lang J. Synaptotagmin 11 interacts with components of the RNA-induced silencing complex RISC in clonal pancreatic β-cells. FEBS Lett 2014; 588:2217-22. [PMID: 24882364 DOI: 10.1016/j.febslet.2014.05.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 05/08/2014] [Accepted: 05/14/2014] [Indexed: 01/06/2023]
Abstract
Synaptotagmins are two C2 domain-containing transmembrane proteins. The function of calcium-sensitive members in the regulation of post-Golgi traffic has been well established whereas little is known about the calcium-insensitive isoforms constituting half of the protein family. Novel binding partners of synaptotagmin 11 were identified in β-cells. A number of them had been assigned previously to ER/Golgi derived-vesicles or linked to RNA synthesis, translation and processing. Whereas the C2A domain interacted with the Q-SNARE Vti1a, the C2B domain of syt11 interacted with the SND1, Ago2 and FMRP, components of the RNA-induced silencing complex (RISC). Binding to SND was direct via its N-terminal tandem repeats. Our data indicate that syt11 may provide a link between gene regulation by microRNAs and membrane traffic.
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Affiliation(s)
| | - Valérie Lagrée
- Université de Bordeaux, UMR CNRS 5248, F-33607 Pessac, France
| | | | | | - Julien Papin
- Université de Bordeaux, UMR CNRS 5248, F-33607 Pessac, France
| | - Itsaso Garcia-Arcos
- University of the Basque Country, Faculty of Medicine and Dentistry, Department of Physiology, Bilbao, Spain
| | - Anne Lajoix
- Université Montpellier 1, CNRS FRE 3400, Faculté de Pharmacie, F-34093 Montpellier Cedex 5, France
| | | | | | | | - Begoña Ochoa
- University of the Basque Country, Faculty of Medicine and Dentistry, Department of Physiology, Bilbao, Spain
| | - Jochen Lang
- Université de Bordeaux, UMR CNRS 5248, F-33607 Pessac, France.
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19
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Duan Z, Zhao X, Fu X, Su C, Xin L, Saarikettu J, Yang X, Yao Z, Silvennoinen O, Wei M, Yang J. Tudor-SN, a novel coactivator of peroxisome proliferator-activated receptor γ protein, is essential for adipogenesis. J Biol Chem 2014; 289:8364-74. [PMID: 24523408 DOI: 10.1074/jbc.m113.523456] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Adipogenesis, in which mesenchymal precursor cells differentiate into mature adipocytes, is a well orchestrated process. In the present study we identified Tudor-SN as a novel co-activator of the transcription factor peroxisome proliferator-activated receptor γ (PPARγ). We provide the first evidence that Tudor-SN and PPARγ exist in the same complex. Both are up-regulated by the early factor C/EBPβ during adipogenesis and significantly influence the regulation of PPARγ target genes in both 3T3-L1 pre-adipocyte and mouse embryonic fibroblasts (MEF) upon exposure to a mixture of hormonal mixture. Moreover, aP2-PPARγ response element (PPRE) interacts with both PPARγ and Tudor-SN, and the gene transcriptional activation of PPRE-luc is enhanced by ectopic expression of Tudor-SN. Deletion of Tudor-SN protein (MEF-KO) affects but does not completely abolish the association of PPARγ and aP2-PPRE. Loss-of-function studies further verified that Tudor-SN is required for adipogenesis, as deletion of Tudor-SN (MEF-KO) impairs dexamethasone, 3-isobutyl-1-methylxanthine, and insulin (DMI)-induced adipocyte differentiation and the expression of PPARγ target genes, such as aP2 and adipsin. Furthermore, H3 acetylation levels were lower in MEF-KO than MEF-WT. Both HDAC1 and HDAC3 are stably associated with PPARγ in MEF-KO, whereas only a small amount of association was observed in MEF-WT after 5 days of treatment during adipogenesis. PPARγ requires various co-activators or co-repressors, which may dynamically associate with and regulate the higher order chromatin remodeling of the promoter region of PPARγ-bound target genes; Tudor-SN is likely one of these co-activators.
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Affiliation(s)
- Zhongchao Duan
- From the Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences
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20
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Involvement of lipid droplets in hepatic responses to lipopolysaccharide treatment in mice. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1357-67. [DOI: 10.1016/j.bbalip.2013.04.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 04/05/2013] [Accepted: 04/30/2013] [Indexed: 01/07/2023]
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21
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Rueda Y, Garcia-Arcos I, Aspichueta P, Ochoa B, Palacios L, Fresnedo O. Infection of primary hepatocytes with adenoviral vectors alters biliary lipid metabolism. J Physiol Sci 2013; 63:225-9. [PMID: 23558863 PMCID: PMC10717407 DOI: 10.1007/s12576-013-0260-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 03/14/2013] [Indexed: 10/27/2022]
Abstract
In the context of a study of the involvement of SND1 (also known as coactivator p100) in biliary lipid secretion by primary rat hepatocytes, first-generation adenoviral vectors were used to promote the overexpression and underexpression of the protein SND1. Although differential expression of SND1 did not result in significant changes in the processes studied, some effects of the adenoviral infection itself were observed. In particular, infected hepatocytes showed a higher intracellular taurocholate accumulation capacity. Additionally, small heterodimer partner (SHP) and farnesoid X receptor (FXR), which are nuclear receptors essential for the regulation of bile salt metabolism and transport, were underregulated at the mRNA level. Our results suggest that adenoviral vectors could be altering some important control mechanism and indicate that adenoviral vectors should be used with caution as transfection vectors for hepatocytes when biliary lipid metabolism is to be studied.
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Affiliation(s)
- Yuri Rueda
- Department of Physiology, Faculty of Medicine and Dentistry of the University of the Basque Country UPV/EHU, Bº Sarriena s/n 48940 Leioa, Bizkaia, Spain
| | - Itsaso Garcia-Arcos
- Department of Physiology, Faculty of Medicine and Dentistry of the University of the Basque Country UPV/EHU, Bº Sarriena s/n 48940 Leioa, Bizkaia, Spain
- Present Address: Division of Preventive Medicine and Nutrition, College of Physicians and Surgeons, Columbia University School of Medicine, New York, USA
| | - Patricia Aspichueta
- Department of Physiology, Faculty of Medicine and Dentistry of the University of the Basque Country UPV/EHU, Bº Sarriena s/n 48940 Leioa, Bizkaia, Spain
| | - Begoña Ochoa
- Department of Physiology, Faculty of Medicine and Dentistry of the University of the Basque Country UPV/EHU, Bº Sarriena s/n 48940 Leioa, Bizkaia, Spain
| | - Lourdes Palacios
- Department of Physiology, Faculty of Medicine and Dentistry of the University of the Basque Country UPV/EHU, Bº Sarriena s/n 48940 Leioa, Bizkaia, Spain
- Present Address: Progenika Biopharma S.A., Technologic Park of Bizkaia, Derio, Spain
| | - Olatz Fresnedo
- Department of Physiology, Faculty of Medicine and Dentistry of the University of the Basque Country UPV/EHU, Bº Sarriena s/n 48940 Leioa, Bizkaia, Spain
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22
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Wang Z, Ni J, Shao D, Liu J, Shen Y, Zhou L, Huang Y, Yu C, Wang J, Xue H, Lu L. Elevated transcriptional co-activator p102 mediates angiotensin II type 1 receptor up-regulation and extracellular matrix overproduction in the high glucose-treated rat glomerular mesangial cells and isolated glomeruli. Eur J Pharmacol 2013; 702:208-17. [PMID: 23376562 DOI: 10.1016/j.ejphar.2013.01.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 01/09/2013] [Accepted: 01/16/2013] [Indexed: 12/11/2022]
Abstract
P102 is a multifunctional transcriptional co-activator. This experiment is designed to investigate the role of p102 in the activation of renin-angiotensin system (RAS) and sequentially extracellular matrix (ECM) over synthesis in diabetic nephropathy. Rat glomerular mesangial cells (MCs) or isolated glomeruli were cultured in normal glucose (NG, 5.5mM) or high glucose (HG, 25 mM) DMEM. The generation of reactive oxygen species was measured by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescent probe assay. The protein levels were analyzed by Western blot and the mRNA levels were evaluated by real-time PCR. HG treatment induced an increase in reactive oxygen species production. Culturing the cells in HG for 48 h, p102 mRNA and protein, angiotensin II type 1 receptor (AT1 receptor) mRNA, transforming growth factor-β1 (TGF-β1) and fibronectin proteins were significantly increased. NADPH oxidase inhibitor DPI blocked the HG-induced p102, TGF-β1 and fibronetcin elevations. Knockdown on p102 expression by siRNA depressed the HG-induced AT1 receptor up-regulation as well as the increases in TGF-β1 and fibronectin. In contrast, AT1 receptor antagonist candesartan did not influence p102 levels under either NG or HG condition, but blocked the HG-induced TGF-β1 and fibronectin increases. The results from isolated glomeruli were consistent with that of MCs, which showed that HG exposure stimulated the expression of p102. These results suggest that the overproduction of reactive oxygen species at the early stage of HG incubation stimulates p102 synthesis, which in turn up-regulates AT1 receptor expression. The activation of RAS stimulates TGF-β1 and fibronectin production, which further results in ECM accumulation.
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Affiliation(s)
- Zhen Wang
- Department of Physiology and Pathophysiology, Shanghai Medical College, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
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23
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Buqué X, Cano A, Miquilena-Colina ME, García-Monzón C, Ochoa B, Aspichueta P. High insulin levels are required for FAT/CD36 plasma membrane translocation and enhanced fatty acid uptake in obese Zucker rat hepatocytes. Am J Physiol Endocrinol Metab 2012; 303:E504-14. [PMID: 22693206 DOI: 10.1152/ajpendo.00653.2011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In myocytes and adipocytes, insulin increases fatty acid translocase (FAT)/CD36 translocation to the plasma membrane (PM), enhancing fatty acid (FA) uptake. Evidence links increased hepatic FAT/CD36 protein amount and gene expression with hyperinsulinemia in animal models and patients with fatty liver, but whether insulin regulates FAT/CD36 expression, amount, distribution, and function in hepatocytes is currently unknown. To investigate this, FAT/CD36 protein content in isolated hepatocytes, subfractions of organelles, and density-gradient isolated membrane subfractions was analyzed in obese and lean Zucker rats by Western blotting in liver sections by immunohistochemistry and in hepatocytes by immunocytochemistry. The uptake of oleate and oleate incorporation into lipids were assessed in hepatocytes at short time points (30-600 s). We found that FAT/CD36 protein amount at the PM was higher in hepatocytes from obese rats than from lean controls. In obese rat hepatocytes, decreased cytoplasmatic content of FAT/CD36 and redistribution from low- to middle- to middle- to high-density subfractions of microsomes were found. Hallmarks of obese Zucker rat hepatocytes were increased amount of FAT/CD36 protein at the PM and enhanced FA uptake and incorporation into triglycerides, which were maintained only when exposed to hyperinsulinemic conditions (80 mU/l). In conclusion, high insulin levels are required for FAT/CD36 translocation to the PM in obese rat hepatocytes to enhance FA uptake and triglyceride synthesis. These results suggest that the hyperinsulinemia found in animal models and patients with insulin resistance and fatty liver might contribute to liver fat accumulation by inducing FAT/CD36 functional presence at the PM of hepatocytes.
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Affiliation(s)
- Xabier Buqué
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country UPV/EHU, Leioa, Spain
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24
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Veloso A, Astigarraga E, Barreda-Gómez G, Manuel I, Ferrer I, Giralt MT, Ochoa B, Fresnedo O, Rodríguez-Puertas R, Fernández JA. Anatomical distribution of lipids in human brain cortex by imaging mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:329-338. [PMID: 21472592 DOI: 10.1007/s13361-010-0024-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 08/20/2010] [Accepted: 10/15/2010] [Indexed: 05/30/2023]
Abstract
Molecular mass images of tissues will be biased if differences in the physicochemical properties of the microenvironment affect the intensity of the spectra. To address this issue, we have performed-by means of MALDI-TOF mass spectrometry-imaging on slices and lipidomic analysis in extracts of frontal cortex, both from the same postmortem tissue samples of human brain. An external calibration was used to achieve a mass accuracy of 10 ppm (1σ) in the spectra of the extracts, although the final assignment was based on a comparison with previously reported species. The spectra recorded directly from tissue slices (imaging) show excellent s/n ratios, almost comparable to those obtained from the extracts. In addition, they retain the information about the anatomical distribution of the molecular species present in autopsied frozen tissue. Further comparison between the spectra from lipid extracts devoid of proteins and those recorded directly from the tissue unambiguously show that the differences in lipid composition between gray and white matter observed in the mass images are not an artifact due to microenvironmental influences of each anatomical area on the signal intensity, but real variations in the lipid composition.
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Affiliation(s)
- Antonio Veloso
- Department of Chemical Physics, Faculty of Science and Technology, University of the Basque Country, Bº Sarriena s/n, 48940 Leioa, Spain
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García-Arcos I, González-Kother P, Aspichueta P, Rueda Y, Ochoa B, Fresnedo O. Lipid Analysis Reveals Quiescent and Regenerating Liver-Specific Populations of Lipid Droplets. Lipids 2010; 45:1101-8. [DOI: 10.1007/s11745-010-3492-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 10/19/2010] [Indexed: 12/29/2022]
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dit Frey NF, Muller P, Jammes F, Kizis D, Leung J, Perrot-Rechenmann C, Bianchi MW. The RNA binding protein Tudor-SN is essential for stress tolerance and stabilizes levels of stress-responsive mRNAs encoding secreted proteins in Arabidopsis. THE PLANT CELL 2010; 22:1575-91. [PMID: 20484005 PMCID: PMC2899877 DOI: 10.1105/tpc.109.070680] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 04/29/2010] [Accepted: 05/03/2010] [Indexed: 05/20/2023]
Abstract
Tudor-SN (TSN) copurifies with the RNA-induced silencing complex in animal cells where, among other functions, it is thought to act on mRNA stability via the degradation of specific dsRNA templates. In plants, TSN has been identified biochemically as a cytoskeleton-associated RNA binding activity. In eukaryotes, it has recently been identified as a conserved primary target of programmed cell death-associated proteolysis. We have investigated the physiological role of TSN by isolating null mutations for two homologous genes in Arabidopsis thaliana. The double mutant tsn1 tsn2 displays only mild growth phenotypes under nonstress conditions, but germination, growth, and survival are severely affected under high salinity stress. Either TSN1 or TSN2 alone can complement the double mutant, indicating their functional redundancy. TSN accumulates heterogeneously in the cytosol and relocates transiently to a diffuse pattern in response to salt stress. Unexpectedly, stress-regulated mRNAs encoding secreted proteins are significantly enriched among the transcripts that are underrepresented in tsn1 tsn2. Our data also reveal that TSN is important for RNA stability of its targets. These findings show that TSN is essential for stress tolerance in plants and implicate TSN in new, potentially conserved mechanisms acting on mRNAs entering the secretory pathway.
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Affiliation(s)
- Nicolas Frei dit Frey
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
| | - Philippe Muller
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
| | - Fabien Jammes
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
- Unité de Recherche en Génomique Végétale, Unité Mixte de Recherche, Institut National de la Recherche Agronomique 1165, Centre National de la Recherche Scientifique 8114, Université d'Evry Val d'Essonne, 91057 Evry cedex, France
| | - Dimosthenis Kizis
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
| | - Jeffrey Leung
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
| | - Catherine Perrot-Rechenmann
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
| | - Michele Wolfe Bianchi
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, 91198 Gif sur Yvette cedex, France
- Faculté des Sciences et Technologie, Université Paris Est-Créteil, 94010 Créteil cedex, France
- Address correspondence to
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Garcia-Arcos I, Rueda Y, González-Kother P, Palacios L, Ochoa B, Fresnedo O. Association of SND1 protein to low density lipid droplets in liver steatosis. J Physiol Biochem 2010; 66:73-83. [DOI: 10.1007/s13105-010-0011-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Accepted: 11/03/2009] [Indexed: 10/19/2022]
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Astigarraga E, Barreda-Gómez G, Lombardero L, Fresnedo O, Castaño F, Giralt MT, Ochoa B, Rodríguez-Puertas R, Fernández JA. Profiling and imaging of lipids on brain and liver tissue by matrix-assisted laser desorption/ ionization mass spectrometry using 2-mercaptobenzothiazole as a matrix. Anal Chem 2009; 80:9105-14. [PMID: 18959430 DOI: 10.1021/ac801662n] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
2-Mercaptobenzothiazole (MBT) is employed for the first time as a matrix for the analysis of lipids from tissue extracts using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. We demonstrate that the performance of MBT is superior to that of the matrixes commonly employed for lipids, due to its low vapor pressure, its low acidity, and the formation of small crystals, although because of the strong background at low m/z, it precludes detection of species below approximately 500 Da. This inconvenience can be partly overcome with the formation of Cs adducts. Using a polymer-based dual calibration, a mass accuracy of approximately 10 ppm in lipid extracts and of approximately 80 ppm in tissues is achieved. We present spectra from liver and brain lipid extracts where a large amount of lipid species is identified, in both positive and negative ion modes, with high reproducibility. In addition, the above-mentioned special properties of MBT allow its employment for imaging mass spectrometry. In the present work, images of brain and liver tissues showing different lipid species are presented, demonstrating the advantages of the employment of MBT.
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Affiliation(s)
- Egoitz Astigarraga
- Department of Chemical Physics, Faculty of Science and Technology, University of the Basque Country, B(o) Sarriena s/n, 48940 Leioa, Spain
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29
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López-Soldado I, Avella M, Botham KM. Differential influence of different dietary fatty acids on very low-density lipoprotein secretion when delivered to hepatocytes in chylomicron remnants. Metabolism 2009; 58:186-95. [PMID: 19154951 PMCID: PMC2779336 DOI: 10.1016/j.metabol.2008.09.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 09/22/2008] [Indexed: 11/28/2022]
Abstract
The influence of dietary fats carried in chylomicron remnants on the hepatic secretion of very low-density lipoprotein (VLDL) was investigated using chylomicron remnant-like particles (CRLPs) and cultured rat hepatocytes as the experimental model. Chylomicron remnant-like particles containing triacylglycerol (TG) from palm, olive, or corn (enriched in saturated, monounsaturated, or n-6 polyunsaturated fatty acids) oil, respectively, were incubated with cultured hepatocytes for 5 hours. The medium was then removed and replaced with medium without CRLPs; and the secretion of TG, cholesterol, and apolipoprotein B48 during the following 16 hours was determined. Secretion of TG into the d less than 1.050-g/mL fraction containing VLDL was unaffected by olive CRLPs, but was significantly increased in cells exposed to palm or corn CRLPs in comparison with both olive CRLPs and control incubations without CRLPs. Secretion of apolipoprotein B48, however, was not changed by any of the CRLP types. Apolipoprotein B messenger RNA levels were decreased by olive and corn CRLPs, and 3-hydroxy-3-methylglutaryl coenzyme A reductase messenger RNA abundance was increased by palm CRLPs; but expression of other genes involved in the regulation of VLDL secretion was unaffected. These findings demonstrate that CRLPs enriched in saturated fatty acids or n-6 polyunsaturated fatty acids increase the secretion of TG in VLDL, possibly because of the secretion of larger particles, whereas those enriched in monounsaturated fatty acids have no effect. Thus, different dietary fats have differential effects on VLDL secretion directly when delivered to the liver in chylomicron remnants.
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Affiliation(s)
| | | | - Kathleen M. Botham
- Department of Veterinary Basic Sciences, The Royal Veterinary College, NW1 0TU London, United Kingdom
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Paukku K, Kalkkinen N, Silvennoinen O, Kontula KK, Lehtonen JYA. p100 increases AT1R expression through interaction with AT1R 3'-UTR. Nucleic Acids Res 2008; 36:4474-87. [PMID: 18603592 PMCID: PMC2490763 DOI: 10.1093/nar/gkn411] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
p100 protein (SND1, Tudor-SN) is a multifunctional protein that functions as a co-activator for several transcription factors, has a role in mRNA processing and participates in RNAi-induced silencing complex (RISC) with yet unknown function. In this study we identified a novel function for p100 as a regulator of angiotensin II type 1 receptor (AT1R) expression. The binding of p100 to AT1R 3′-untranslated region (3′-UTR) via staphylococcal nuclease-like (SN-like) domains increased receptor expression by decreasing the rate of mRNA decay and enhancing its translation. Overexpression of p100 increased AT1R expression, whereas decrease in p100 binding to 3′-UTR either by p100 silencing or by the deletion of p100 binding site downregulated receptor expression. The effect of p100 through AT1R 3′-UTR was independent of Argonaute2 (Ago2), a known p100 partner, and was thus RISC-independent. Nucleotides 118 to 120 of the AT1R 3′-UTR were found to be critical for the binding of p100 to 3′-UTR. In summary, p100 is a multifunctional regulator of gene expression that regulates transcription, mRNA maturation, and as described in this article, also mRNA stability and translation.
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Affiliation(s)
- Kirsi Paukku
- Research Program for Molecular Medicine, Biomedicum Helsinki, University of Helsinki, Finland.
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Rodríguez L, Ochoa B, Martínez MJ. NF-Y and Sp1 are involved in transcriptional regulation of rat SND p102 gene. Biochem Biophys Res Commun 2007; 356:226-32. [PMID: 17350600 DOI: 10.1016/j.bbrc.2007.02.110] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Accepted: 02/22/2007] [Indexed: 10/23/2022]
Abstract
SND p102 is a rat liver endoplasmic reticulum cholesterol ester hydrolase recently described as a member of a conserved family of transcriptional coactivators that promotes phospholipid secretion into lipoproteins when overexpressed in hepatocytes. In this work, we report first evidence for a mechanism of transcriptional regulation for the SND p102 (Snd1) gene. Promoter activity of 5' deletion fragments determined in human HepG2 and rat McA-RH7777 hepatoma cells by luciferase reporter gene assays showed a minimal promoter involving two inverted CCAAT boxes. EMSA demonstrated specific binding of Sp1 to GC boxes in the proximal, highly active promoter region besides that of NF-Y to CCAAT boxes reported earlier. Site-directed disruption of such CCAAT and GC boxes led to reduction in transcriptional activity, confirming the functional implication of NF-Y and Sp1 in SND p102 gene transcription.
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Affiliation(s)
- Lorena Rodríguez
- Department of Physiology, University of the Basque Country Medical School, Barrio Sarriena s/n, 48940 Leioa, Vizcaya, Spain
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Rodríguez L, Bartolomé N, Ochoa B, Martínez MJ. Isolation and Characterization of the Rat SND p102 Gene Promoter. Ann N Y Acad Sci 2006; 1091:282-95. [PMID: 17341622 DOI: 10.1196/annals.1378.074] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In this work, we report the isolation and characterization of a 1,688-bp sequence corresponding to the promoter region of the rat endoplasmic reticulum (ER) cholesterol ester hydrolase gene, renamed as staphylococcal nuclease domain-containing protein of 102 kDa (SND p102) in GenBank database according to the structural properties and molecular weight of the protein. The transcription start site was located 216 bases upstream of the ATG start codon by RNA ligase mediated-rapid amplification of cDNA ends (RLM-RACE). Bioinformatic analysis of the isolated sequence revealed a lack of typical promoter TATA box and the presence of GC-rich motifs and CCAAT boxes recognized by Sp 1 and nuclear factor-Y among other putative binding sites for a number of transcription factors implicated in both basal and regulated processes. Electrophoretic mobility shift and supershift assays using nuclear extracts from human (HepG2) and rat (McA-RH7777) hepatoma cells demonstrated that nuclear factor-Y (NF-Y) transcription factor bound to the core sequences at (-257, -253), (-290, -286), and (-370, -366) upstream translation initiation site. The absence of TATA box and the location and reverse orientation of the CCAAT boxes in the promoter region strongly suggest a role for NF-Y in the regulation of transcription of SND p102 gene.
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Affiliation(s)
- Lorena Rodríguez
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country, Sarriena s/n, 48940-Leioa, Bizkaia, Spain
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