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Li X, Fernandes BS, Liu A, Lu Y, Chen J, Zhao Z, Dai Y. Genetically-regulated pathway-polygenic risk score (GRPa-PRS): A risk stratification method to identify genetically regulated pathways in polygenic diseases. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.06.19.23291621. [PMID: 37425929 PMCID: PMC10327215 DOI: 10.1101/2023.06.19.23291621] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Background Alzheimer's disease (AD) is a common neurodegenerative disease in the elderly population, with genetic factors playing an important role. A considerable proportion of elderly people carry a high genetic AD risk but evade AD. On the other hand, some individuals with a low risk for AD eventually develop AD. We hypothesized that unknown counterfactors might be involved in reversing the polygenic risk scores (PRS) prediction, which might provide insights into AD pathogenesis, prevention, and early clinical intervention. Methods We built a novel computational framework to identify genetically-regulated pathways (GRPa) using PRS-based stratification for each cohort. We curated two AD cohorts with genotyping data; the discovery and the replication dataset include 2722 and 2492 individuals, respectively. First, we calculated the optimized PRS model based on the three latest AD GWAS summary statistics for each cohort. Then, we sub-grouped the individuals by their PRS and clinical diagnosis into groups such as cognitively normal (CN) with high PRS for AD (resilient group), AD cases with low PRS (susceptible group), and AD/CNs participants with similar PRS backgrounds. Lastly, we imputed the individual genetically-regulated expression (GReX) and identified the differential GRPas between subgroups with gene-set enrichment analysis and gene-set variational analysis in 2 models with and without the effect of APOE. Results For each subgroup, we conducted the same procedures in both the discovery and replication datasets across three PRS models for comparison. In Model 1 with the APOE region, we identified well-known AD-related pathways, including amyloid-beta clearance, tau protein binding, and astrocytes response to oxidative stress. In Model 2 without the APOE region, synapse function, microglia function, histidine metabolism, and thiolester hydrolase activity were significant, suggesting that they are pathways independent of the effect of APOE. Finally, our GRPa-PRS method reduces the false discovery rate in detecting differential pathways compared to another variants-based pathway PRS method. Conclusions We developed a framework, GRPa-PRS, to systematically explore the differential GRPas among individuals stratified by their estimated PRS. The GReX-level comparison among those groups unveiled new insights into the pathways associated with AD risk and resilience. Our framework can be extended to other polygenic complex diseases.
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Affiliation(s)
- Xiaoyang Li
- Center for Precision Health, McWilliams School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Department of Biostatistics and Data Science, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Brisa S. Fernandes
- Center for Precision Health, McWilliams School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Andi Liu
- Center for Precision Health, McWilliams School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Department of Epidemiology, Human Genetics and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Yimei Lu
- Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Jingchun Chen
- Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Zhongming Zhao
- Center for Precision Health, McWilliams School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Department of Epidemiology, Human Genetics and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Yulin Dai
- Center for Precision Health, McWilliams School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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Zhou Y, Qiao Y, Zhang X, Ma X, Liu H, Wang L. PFOA exposure causes variations of Acot1 among tissues in rats, and Acot1 in serum can be potentially used as a sensitive marker for health monitoring. Toxicol Res (Camb) 2022; 11:872-880. [PMID: 36337235 PMCID: PMC9618101 DOI: 10.1093/toxres/tfac065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 08/26/2022] [Accepted: 09/04/2022] [Indexed: 10/05/2023] Open
Abstract
Perfluorooctanoic acid (PFOA) is a type of 8-carbon perfluoroalkyl substances (PFASs) widely used in industrial and domestic products, which now is a persistent organic pollutant (POP) found in the environment. Its structure is similar to fatty acids, which enables it to induce the expression of ACOT genes. To investigate the expression levels of Acot1 in various tissues and organs after exposure to PFOA for 28 days in rats, and to compare the variations of Acot1 expression in different tissues, we sectioned samples and incubated with Acot1 antibody. The results show that the transcription and protein expression levels of Acot1 in the liver and kidney of rats increased significantly. Meanwhile, the transcription and protein expression of Acot1 gene were also detected in testis, muscle, and adipose. The results of immunohistochemistry were also verified by western blot detection, and we detected the transcription of Acot1 gene in these tissues and found that they all increased in varying degrees. In this study, the expression of Acot1 protein in rat serum was detected for the first time, and the expression of Acot1 in rat serum was found to be significantly increased after PFOA exposure. In addition, the expression level of Acot1 in rat organism was found to be higher than that in the control group after 4 days of depuration for 7 days of acute PFOA exposure, and Acot1 protein expression also showed an increase with increasing exposure time, indicating that Acot1 can be used as a sensitive biomarker for health monitoring of PFOA occupational workers or exposed persons.
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Affiliation(s)
- Yongbing Zhou
- School of Public Health, Bengbu Medical College, Bengbu 233030, PR China
| | - Ying Qiao
- School of Public Health, Bengbu Medical College, Bengbu 233030, PR China
| | - Xuemin Zhang
- Department of Biochemistry and Molecular Biology, School of Laboratory Medicine, Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical College, Bengbu 233030, PR China
| | - Xingzhuang Ma
- School of Public Health, Bengbu Medical College, Bengbu 233030, PR China
| | - Hui Liu
- Department of Biochemistry and Molecular Biology, School of Laboratory Medicine, Anhui Province Key Laboratory of Immunology in Chronic Diseases, Bengbu Medical College, Bengbu 233030, PR China
| | - Li Wang
- School of Public Health, Bengbu Medical College, Bengbu 233030, PR China
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Zheng C, Zhang G, Xie K, Diao Y, Luo C, Wang Y, Shen Y, Xue Q. Pan-Cancer Analysis and Experimental Validation Identify ACOT7 as a Novel Oncogene and Potential Therapeutic Target in Lung Adenocarcinoma. Cancers (Basel) 2022; 14:cancers14184522. [PMID: 36139682 PMCID: PMC9497106 DOI: 10.3390/cancers14184522] [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] [Received: 07/19/2022] [Revised: 09/11/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Acyl-CoA thioesterase 7 (ACOT7) is of great significance in regulating cell cycle, cell proliferation, and glucose metabolism. The function of ACOT7 in pan-cancer and its capacity as a prognostic indicator in lung adenocarcinoma (LUAD) remains unknown. We intended to perform a comprehensive pan-cancer analysis of ACOT7 and to validate its value in LUAD. Methods: The expression levels, prognostic significance, molecular function, signaling pathways, and immune infiltration pattern of ACOT7 in 33 cancers were explored via systematic bioinformatics analysis. Multivariate Cox regression was applied to construct nomograms to predict patients’ prognoses. Moreover, we conducted in vitro experiments including CCK8, scratch, Transwell, and Matrigel assays to further explore the function of ACOT7 in LUAD. Results: Patients with high ACOT7 expression have notably poorer long-term survival in many cancer types, including LUAD. Further enrichment analyses reveal that ACOT7 is involved in immune cells’ infiltration and is substantially related to the cancer−immune microenvironment. ACOT7 could influence drug sensitivities, including afatinib, gefitinib, ibrutinib, lapatinib, osimertinib, sapitinib, taselisib, and PLX-4720 (all p < 0.01). A nomogram demonstrated a fair predictive value of ACOT7 in LUAD (C-index: 0.613, 95% CI: 0.568−0.658). The proliferation and migration of PC9 cells were significantly repressed when ACOT7 expression was downregulated. Conclusion: As an oncogene, ACOT7 is critical in the tumor microenvironment of pan-cancer and might be a novel therapeutic target for LUAD.
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Affiliation(s)
- Chao Zheng
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Department of Cardiothoracic Surgery, Jinling Hospital, Medical School of Southeast University, Nanjing 210009, China
| | - Guochao Zhang
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
| | - Kai Xie
- Department of Cardiothoracic Surgery, Jinling Hospital, Nanjing Medical University, Nanjing 210009, China
| | - Yifei Diao
- Department of Cardiothoracic Surgery, Jinling Hospital, Medical School of Nanjing University, Nanjing 210009, China
| | - Chao Luo
- Department of Cardiothoracic Surgery, Jinling Hospital, Southern Medical University, Guangzhou 510515, China
| | - Yanqing Wang
- Department of Cardiology, Jinling Hospital, Nanjing University, Nanjing 210009, China
- Correspondence: (Y.W.); (Q.X.)
| | - Yi Shen
- Department of Cardiothoracic Surgery, Jinling Hospital, Medical School of Southeast University, Nanjing 210009, China
| | - Qi Xue
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
- Correspondence: (Y.W.); (Q.X.)
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Xie X, Chen C, Feng S, Zuo S, Zhao X, Li H. Acyl-CoA Thioesterase 7 is Transcriptionally Activated by Krüppel-Like Factor 13 and Promotes the Progression of Hepatocellular Carcinoma. J Hepatocell Carcinoma 2022; 8:1623-1641. [PMID: 34993160 PMCID: PMC8711737 DOI: 10.2147/jhc.s338353] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 12/01/2021] [Indexed: 12/14/2022] Open
Abstract
Purpose Acyl-CoA thioesterase 7(ACOT7) plays an important role in the metabolism of fatty acids. Hepatocellular carcinoma (HCC) has an abnormal lipid profile, and the role of ACOT7 in hepatocellular carcinoma has not been detailedly elucidated. Therefore, we conducted the study to explore the role of ACOT7 in HCC. Materials and Methods The ACOT7 and Krüppel-like factor 13 (KLF13) mRNA expression levels were obtained from The Cancer Genome Atlas (TCGA) database. Bioinformatics analysis identified the underlying upstream regulator of ACOT7. Quantitative real-time PCR was used to detect the expression of mRNA, and immunohistochemical staining and Western blotting were used to detect the expression of protein. Cell Counting Kit-8 and EdU assays were employed to assess the proliferation of HCC cells. Wound-healing and Transwell migration assays were utilized to test the migration ability of HCC cells. Dual-luciferase reporter assay and ChIP assay were used to explore the potential mechanism. Gas chromatography-mass spectrometer was used to analyze the content of free fatty acids. Xenograft tumour growth was used to evaluate the effect of ACOT7 in vivo. Results According to The Cancer Genome Atlas (TCGA) database, ACOT7 mRNA was found to be upregulated and predicted the poor prognosis. Overexpression of ACOT7 enhanced the proliferation, migration and invasion abilities of HCC cells in vitro, as well as the HCC cells proliferation in vivo. Moreover, ACOT7 overexpression increased the yield of the monounsaturated fatty acid Oleic acid (C18:1), which strengthened the proliferation and migration abilities of HCC cells. Mechanistically, KLF13 transcriptionally promoted ACOT7 expression. Further, KLF13 was also overexpressed in HCC tissues and facilitated HCC progression. Conclusion Acyl-CoA thioesterase 7 is transcriptionally activated by Krüppel-like factor 13 and promotes the progression of hepatocellular carcinoma.
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Affiliation(s)
- Xingming Xie
- School of Clinical Medicine, Guizhou Medical University, Guiyang, Guizhou, People's Republic of China.,Department of Hepatobiliary Surgery, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, People's Republic of China
| | - Chaochun Chen
- School of Clinical Medicine, Guizhou Medical University, Guiyang, Guizhou, People's Republic of China.,Department of Hepatobiliary Surgery, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, People's Republic of China
| | - Shu Feng
- School of Clinical Medicine, Guizhou Medical University, Guiyang, Guizhou, People's Republic of China.,Department of Infectious Diseases, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, People's Republic of China
| | - Shi Zuo
- Department of Hepatobiliary Surgery, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, People's Republic of China
| | - Xueke Zhao
- Department of Infectious Diseases, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, People's Republic of China
| | - Haiyang Li
- School of Clinical Medicine, Guizhou Medical University, Guiyang, Guizhou, People's Republic of China.,Department of Hepatobiliary Surgery, The Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, People's Republic of China
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Feng H, Liu X. Interaction between ACOT7 and LncRNA NMRAL2P via Methylation Regulates Gastric Cancer Progression. Yonsei Med J 2020; 61:471-481. [PMID: 32469171 PMCID: PMC7256001 DOI: 10.3349/ymj.2020.61.6.471] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/13/2020] [Accepted: 04/01/2020] [Indexed: 12/16/2022] Open
Abstract
PURPOSE Gastric cancer (GC) has a very poor prognosis when diagnosed at a late stage. Acyl-CoA thioesterase 7 (ACOT7) is a major isoform of the acyl coenzyme family that catalyzes the hydrolysis of fatty acyl-CoAs into unesterified free fatty acid and coenzyme A. The purpose of this study was to investigate the expression levels of ACOT7 in GC and mechanisms related therewith. MATERIALS AND METHODS Screening of systematic biology studies revealed ACOT7 as a key gene in GC, as well as involvement of the long non-coding RNA NMRAL2P in ACOT7 expression. In this study, GC tissues and adjacent tissue samples were obtained from 10 GC patients at the Department of Gastrointestinal Surgery. GES1 and SGC-7901 cells were collected and treated to silence ACOT7 and overexpress NMRAL2P. The expressions of ACOT7 and NMRAL2P were detected by real-time quantitative PCR and Western blot. Additionally, cell proliferation, apoptosis, migration, and invasion were examined. RESULTS ACOT7 was upregulated in gastric tumor tissues and GC cell lines. ACOT7 gene silencing induced a less malignant phenotype and was closely correlated to reduced cell proliferation and migration, altered cell cycle, and increased apoptosis. Furthermore, NMRAL2P was downregulated in tumor tissues and GC cell lines. NMRAL2P overexpression induced a more malignant phenotype and significantly inhibited the expression of ACOT7. Importantly, NMRAL2P indirectly methylated ACOT7 by binding to DNMT3b, thereby suppressing ACOT7 expression. CONCLUSION NMRAL2P activation suppresses ACOT7 expression in GC. Thus, ACOT7 could be a promising target for the treatment of GC.
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Affiliation(s)
- Huiqin Feng
- Department of Internal Medicine, Tongxiang Chinese Medicine Hospital, Tongxiang, China
| | - Xiaojian Liu
- Department of Surgery, Tongxiang First People's Hospital, Tongxiang, China.
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Steensels S, Ersoy BA. Fatty acid activation in thermogenic adipose tissue. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:79-90. [PMID: 29793055 DOI: 10.1016/j.bbalip.2018.05.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 03/10/2018] [Accepted: 05/17/2018] [Indexed: 02/07/2023]
Abstract
Channeling carbohydrates and fatty acids to thermogenic tissues, including brown and beige adipocytes, have garnered interest as an approach for the management of obesity-related metabolic disorders. Mitochondrial fatty acid oxidation (β-oxidation) is crucial for the maintenance of thermogenesis. Upon cellular fatty acid uptake or following lipolysis from triglycerides (TG), fatty acids are esterified to coenzyme A (CoA) to form active acyl-CoA molecules. This enzymatic reaction is essential for their utilization in β-oxidation and thermogenesis. The activation and deactivation of fatty acids are regulated by two sets of enzymes called acyl-CoA synthetases (ACS) and acyl-CoA thioesterases (ACOT), respectively. The expression levels of ACS and ACOT family members in thermogenic tissues will determine the substrate availability for β-oxidation, and consequently the thermogenic capacity. Although the role of the majority of ACS and ACOT family members in thermogenesis remains unclear, recent proceedings link the enzymatic activities of ACS and ACOT family members to metabolic disorders and thermogenesis. Elucidating the contributions of specific ACS and ACOT family members to trafficking of fatty acids towards thermogenesis may reveal novel targets for modulating thermogenic capacity and treating metabolic disorders.
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Affiliation(s)
- Sandra Steensels
- Department of Medicine, Division of Gastroenterology and Hepatology, Weill Cornell Medical College, New York, NY, USA
| | - Baran A Ersoy
- Department of Medicine, Division of Gastroenterology and Hepatology, Weill Cornell Medical College, New York, NY, USA.
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Tillander V, Alexson SEH, Cohen DE. Deactivating Fatty Acids: Acyl-CoA Thioesterase-Mediated Control of Lipid Metabolism. Trends Endocrinol Metab 2017; 28:473-484. [PMID: 28385385 PMCID: PMC5474144 DOI: 10.1016/j.tem.2017.03.001] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 03/01/2017] [Indexed: 12/28/2022]
Abstract
The cellular uptake of free fatty acids (FFA) is followed by esterification to coenzyme A (CoA), generating fatty acyl-CoAs that are substrates for oxidation or incorporation into complex lipids. Acyl-CoA thioesterases (ACOTs) constitute a family of enzymes that hydrolyze fatty acyl-CoAs to form FFA and CoA. Although biochemically and biophysically well characterized, the metabolic functions of these enzymes remain incompletely understood. Existing evidence suggests regulatory roles in controlling rates of peroxisomal and mitochondrial fatty acyl-CoA oxidation, as well as in the subcellular trafficking of fatty acids. Emerging data implicate ACOTs in the pathogenesis of metabolic diseases, suggesting that better understanding their pathobiology could reveal unique targets in the management of obesity, diabetes, and nonalcoholic fatty liver disease.
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Affiliation(s)
- Veronika Tillander
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, 14186, Sweden
| | - Stefan E H Alexson
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, 14186, Sweden
| | - David E Cohen
- Division of Gastroenterology and Hepatology, Joan & Sanford I. Weill Department of Medicine, Weill Cornell Medical College, New York, NY 10021, USA.
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Acyl-CoA thioesterase 7 is involved in cell cycle progression via regulation of PKCζ-p53-p21 signaling pathway. Cell Death Dis 2017; 8:e2793. [PMID: 28518146 PMCID: PMC5584527 DOI: 10.1038/cddis.2017.202] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 03/14/2017] [Accepted: 04/06/2017] [Indexed: 11/08/2022]
Abstract
Acyl-CoA thioesterase 7 (ACOT7) is a major isoform of the ACOT family that catalyzes hydrolysis of fatty acyl-CoAs to free fatty acids and CoA-SH. However, canonical and non-canonical functions of ACOT7 remain to be discovered. In this study, for the first time, ACOT7 was shown to be responsive to genotoxic stresses such as ionizing radiation (IR) and the anti-cancer drug doxorubicin in time- and dose-dependent manners. ACOT7 knockdown induced cytostasis via activation of the p53-p21 signaling pathway without a DNA damage response. PKCζ was specifically involved in ACOT7 depletion-mediated cell cycle arrest as an upstream molecule of the p53-p21 signaling pathway in MCF7 human breast carcinoma and A549 human lung carcinoma cells. Of the other members of the ACOT family, including ACOT1, 4, 8, 9, 11, 12, and 13 that were expressed in human, ACOT4, 8, and 12 were responsive to genotoxic stresses. However, none of those had a role in cytostasis via activation of the PKCζ-p53-p21 signaling pathway. Analysis of the ACOT7 prognostic value revealed that low ACOT7 levels prolonged overall survival periods in breast and lung cancer patients. Furthermore, ACOT7 mRNA levels were higher in lung cancer patient tissues compared to normal tissues. We also observed a synergistic effect of ACOT7 depletion in combination with either IR or doxorubicin on cell proliferation in breast and lung cancer cells. Together, our data suggest that a low level of ACOT7 may be involved, at least in part, in the prevention of human breast and lung cancer development via regulation of cell cycle progression.
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Swomley AM, Triplett JC, Keeney JT, Warrier G, Pearson KJ, Mattison JA, de Cabo R, Cai J, Klein JB, Butterfield DA. Comparative proteomic analyses of the parietal lobe from rhesus monkeys fed a high-fat/sugar diet with and without resveratrol supplementation, relative to a healthy diet: Insights into the roles of unhealthy diets and resveratrol on function. J Nutr Biochem 2016; 39:169-179. [PMID: 27840293 DOI: 10.1016/j.jnutbio.2016.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 09/30/2016] [Accepted: 10/10/2016] [Indexed: 12/11/2022]
Abstract
A diet consisting of a high intake of saturated fat and refined sugars is characteristic of a Western-diet and has been shown to have a substantial negative effect on human health. Expression proteomics were used to investigate changes to the parietal lobe proteome of rhesus monkeys consuming either a high fat and sugar (HFS) diet, a HFS diet supplemented with resveratrol (HFS+RSV), or a healthy control diet for 2 years. Here we discuss the modifications in the levels of 12 specific proteins involved in various cellular systems including metabolism, neurotransmission, structural integrity, and general cellular signaling following a nutritional intervention. Our results contribute to a better understanding of the mechanisms by which resveratrol functions through the up- or down-regulation of proteins in different cellular sub-systems to affect the overall health of the brain.
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Affiliation(s)
- Aaron M Swomley
- Department of Chemistry, University of Kentucky, Lexington, KY 40536, USA; Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536, USA
| | - Judy C Triplett
- Department of Chemistry, University of Kentucky, Lexington, KY 40536, USA; Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536, USA
| | - Jeriel T Keeney
- Department of Chemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Govind Warrier
- Department of Chemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Kevin J Pearson
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536, USA; Molecular and Biomedical Pharmacology and Nutrition, University of Kentucky, Lexington, KY 40536, USA
| | - Julie A Mattison
- Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD 21224, USA
| | - Jian Cai
- Proteomics Center, University of Louisville, Louisville, KY 40202, USA
| | - Jon B Klein
- Proteomics Center, University of Louisville, Louisville, KY 40202, USA
| | - D Allan Butterfield
- Department of Chemistry, University of Kentucky, Lexington, KY 40536, USA; Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536, USA.
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Martinez-Sanchez A, Pullen TJ, Chabosseau P, Zhang Q, Haythorne E, Cane MC, Nguyen-Tu MS, Sayers SR, Rutter GA. Disallowance of Acot7 in β-Cells Is Required for Normal Glucose Tolerance and Insulin Secretion. Diabetes 2016; 65:1268-82. [PMID: 26861785 PMCID: PMC6101210 DOI: 10.2337/db15-1240] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 02/04/2016] [Indexed: 12/18/2022]
Abstract
Encoding acyl-CoA thioesterase-7 (Acot7) is one of ∼60 genes expressed ubiquitously across tissues but relatively silenced, or disallowed, in pancreatic β-cells. The capacity of ACOT7 to hydrolyze long-chain acyl-CoA esters suggests potential roles in β-oxidation, lipid biosynthesis, signal transduction, or insulin exocytosis. We explored the physiological relevance of β-cell-specific Acot7 silencing by re-expressing ACOT7 in these cells. ACOT7 overexpression in clonal MIN6 and INS1(832/13) β-cells impaired insulin secretion in response to glucose plus fatty acids. Furthermore, in a panel of transgenic mouse lines, we demonstrate that overexpression of mitochondrial ACOT7 selectively in the adult β-cell reduces glucose tolerance dose dependently and impairs glucose-stimulated insulin secretion. By contrast, depolarization-induced secretion was unaffected, arguing against a direct action on the exocytotic machinery. Acyl-CoA levels, ATP/ADP increases, membrane depolarization, and Ca(2+) fluxes were all markedly reduced in transgenic mouse islets, whereas glucose-induced oxygen consumption was unchanged. Although glucose-induced increases in ATP/ADP ratio were similarly lowered after ACOT7 overexpression in INS1(832/13) cells, changes in mitochondrial membrane potential were unaffected, consistent with an action of Acot7 to increase cellular ATP consumption. Because Acot7 mRNA levels are increased in human islets in type 2 diabetes, inhibition of the enzyme might provide a novel therapeutic strategy.
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Affiliation(s)
- Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | - Timothy J Pullen
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | - Pauline Chabosseau
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | | | - Elizabeth Haythorne
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | - Matthew C Cane
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | - Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | - Sophie R Sayers
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K.
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Triplett JC, Swomley A, Kirk J, Lewis K, Orr M, Rodriguez K, Cai J, Klein JB, Buffenstein R, Butterfield DA. Metabolic clues to salubrious longevity in the brain of the longest-lived rodent: the naked mole-rat. J Neurochem 2015; 134:538-50. [PMID: 25940666 DOI: 10.1111/jnc.13149] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 04/13/2015] [Accepted: 04/23/2015] [Indexed: 12/16/2022]
Abstract
Naked mole-rats (NMRs) are the oldest-living rodent species. Living underground in a thermally stable ecological niche, NMRs have evolved certain exceptional traits, resulting in sustained health spans, negligible cognitive decline, and a pronounced resistance to age-related disease. Uncovering insights into mechanisms underlying these extraordinary traits involved in successful aging may conceivably provide crucial clues to extend the human life span and health span. One of the most fundamental processes inside the cell is the production of ATP, which is an essential fuel in driving all other energy-requiring cellular activities. Not surprisingly, a prominent hallmark in age-related diseases, such as neurodegeneration and cancer, is the impairment and dysregulation of metabolic pathways. Using a two-dimensional polyacrylamide gel electrophoresis proteomics approach, alterations in expression and phosphorylation levels of metabolic proteins in the brains of NMRs, aged 2-24 years, were evaluated in an age-dependent manner. We identified 13 proteins with altered levels and/or phosphorylation states that play key roles in various metabolic pathways including glycolysis, β-oxidation, the malate-aspartate shuttle, the Tricarboxylic Acid Cycle (TCA) cycle, the electron transport chain, NADPH production, as well as the production of glutamate. New insights into potential pathways involved in metabolic aspects of successful aging have been obtained by the identification of key proteins through which the NMR brain responds and adapts to the aging process and how the NMR brain adapted to resist age-related degeneration. This study examines the changes in the proteome and phosphoproteome in the brain of the naked mole-rat aged 2-24 years. We identified 13 proteins (labeled in red) with altered expression and/or phosphorylation levels that are conceivably associated with sustained metabolic functions in the oldest NMRs that may promote a sustained health span and life span.
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Affiliation(s)
- Judy C Triplett
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Aaron Swomley
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Jessime Kirk
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Katilyn Lewis
- Sam and Ann Barsop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas, USA.,Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Miranda Orr
- Sam and Ann Barsop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas, USA.,Department of Physiology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Karl Rodriguez
- Sam and Ann Barsop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas, USA.,Department of Physiology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Jian Cai
- Department of Nephrology and Proteomics Center, University of Louisville, Louisville, Kentucky, USA
| | - Jon B Klein
- Department of Nephrology and Proteomics Center, University of Louisville, Louisville, Kentucky, USA
| | - Rochelle Buffenstein
- Sam and Ann Barsop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas, USA.,Department of Physiology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - D Allan Butterfield
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA.,Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
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12
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Zhang J, Li C, Tang X, Lu Q, Sa R, Zhang H. High Concentrations of Atmospheric Ammonia Induce Alterations in the Hepatic Proteome of Broilers (Gallus gallus): An iTRAQ-Based Quantitative Proteomic Analysis. PLoS One 2015; 10:e0123596. [PMID: 25901992 PMCID: PMC4406733 DOI: 10.1371/journal.pone.0123596] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 02/20/2015] [Indexed: 12/30/2022] Open
Abstract
With the development of the poultry industry, ammonia, as a main contaminant in the air, is causing increasing problems with broiler health. To date, most studies of ammonia toxicity have focused on the nervous system and the gastrointestinal tract in mammals. However, few detailed studies have been conducted on the hepatic response to ammonia toxicity in poultry. The molecular mechanisms that underlie these effects remain unclear. In the present study, our group applied isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomic analysis to investigate changes in the protein profile change in hepatic tissue of broilers exposed to high concentrations of atmospheric ammonia, with the goal of characterizing the molecular mechanisms of chronic liver injury from exposure to high ambient levels of ammonia. Overall, 30 differentially expressed proteins that are involved in nutrient metabolism (energy, lipid, and amino acid), immune response, transcriptional and translational regulation, stress response, and detoxification were identified. In particular, two of these proteins, beta-1 galactosidase (GLB1) and a kinase (PRKA) anchor protein 8-like (AKAP8 L), were previously suggested to be potential biomarkers of chronic liver injury. In addition to the changes in the protein profile, serum parameters and histochemical analyses of hepatic tissue also showed extensive hepatic damage in ammonia-exposed broilers. Altogether, these findings suggest that longtime exposure to high concentrations of atmospheric ammonia can trigger chronic hepatic injury in broilers via different mechanisms, providing new information that can be used for intervention using nutritional strategies in the future.
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Affiliation(s)
- Jize Zhang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Cong Li
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiangfang Tang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qingping Lu
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Renna Sa
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hongfu Zhang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- * E-mail:
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13
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Ohtomo T, Nakao C, Sumiya M, Kaminuma O, Abe A, Mori A, Inaba N, Kato T, Yamada J. Identification of acyl-CoA thioesterase in mouse mesenteric lymph nodes. Biol Pharm Bull 2014; 36:866-71. [PMID: 23649344 DOI: 10.1248/bpb.b12-01088] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Acyl-CoA thioesterases (ACOTs) are a group of enzymes that catalyze the hydrolysis of fatty acyl-CoAs to free fatty acids and CoA, with the potential to regulate the intracellular levels of these molecules. In this study, we show that a cytosolic isoform, ACOT7, is expressed at a significant level in the mesenteric lymph nodes (MLNs) of mice. While crude preparations of the mesenteric visceral fat contained significant levels of palmitoyl-CoA thioesterase activity, enzyme activity was concentrated 6.9-fold in MLNs compared with the residual adipose portion after excision of MLNs. When MLN homogenates were centrifuged, 82% of the enzyme activity was recovered in the cytosolic fraction, concomitant with almost exclusive recovery of ACOT7. Immunoprecipitation using anti-ACOT7 antibody estimated that 87% of enzyme activity in the homogenates was accounted for by ACOT7. On MLN sections, the germinal centers of secondary lymphoid follicles were immunostained with the antibody. In MLNs of mice fasted for 16 h, ACOT7 levels were induced 1.8-fold, which reflected a 1.5-fold increase in enzyme activity. These findings suggest that ACOT7 may be involved in dietary intake-associated responses in fatty acid metabolism in MLNs.
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Affiliation(s)
- Takayuki Ohtomo
- Department of Pharmacotherapeutics, Tokyo University of Pharmacy and Life Sciences, Tokyo 192–0392, Japan
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14
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Acyl coenzyme A thioesterase 7 regulates neuronal fatty acid metabolism to prevent neurotoxicity. Mol Cell Biol 2013; 33:1869-82. [PMID: 23459938 DOI: 10.1128/mcb.01548-12] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Numerous neurological diseases are associated with dysregulated lipid metabolism; however, the basic metabolic control of fatty acid metabolism in neurons remains enigmatic. Here we have shown that neurons have abundant expression and activity of the long-chain cytoplasmic acyl coenzyme A (acyl-CoA) thioesterase 7 (ACOT7) to regulate lipid retention and metabolism. Unbiased and targeted metabolomic analysis of fasted mice with a conditional knockout of ACOT7 in the nervous system, Acot7(N-/-), revealed increased fatty acid flux into multiple long-chain acyl-CoA-dependent pathways. The alterations in brain fatty acid metabolism were concomitant with a loss of lean mass, hypermetabolism, hepatic steatosis, dyslipidemia, and behavioral hyperexcitability in Acot7(N-/-) mice. These failures in adaptive energy metabolism are common in neurodegenerative diseases. In agreement, Acot7(N-/-) mice exhibit neurological dysfunction and neurodegeneration. These data show that ACOT7 counterregulates fatty acid metabolism in neurons and protects against neurotoxicity.
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15
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Ohtomo T, Hoshino A, Yajima M, Tsuchiya A, Momose A, Tanonaka K, Toyoda H, Kato T, Yamada J. Expression and distribution of acyl-CoA thioesterases in the white adipose tissue of rats. Histochem Cell Biol 2013; 140:223-32. [PMID: 23385637 DOI: 10.1007/s00418-013-1079-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2013] [Indexed: 12/28/2022]
Abstract
Acyl-CoA thioesterases (Acots) are enzymes that catalyze the hydrolysis of fatty acyl-CoAs to free fatty acids and coenzyme A, and have the potential to regulate the intracellular levels of these molecules. In this study, we show that a cytosolic isoform, Acot1, is expressed and distributed in immature adipocytes located in the perivascular region of the white adipose tissue (WAT) of rats. Immunoblot analyses detected Acot1 in all of the WATs examined, while immunohistochemistry revealed positively stained layered structures surrounding the adventitia of blood vessels in the subcutaneous WAT. When the subcutaneous WAT was digested with collagenase and centrifuged, Acot1 was recovered in the stromal vascular fraction (SVF), and not in the large mature adipocytes. In the SVF, undigested cells attached to short tubular fragments of blood vessels showed positive immunostaining, as well as a proportion of the dispersed cells. These fibroblast-like cells contained fine particulate lipid droplets, stained by oil-red O dye, in their cytoplasm, or expressed fatty acid-binding protein 4, an adipocyte marker. After induction of adipocyte differentiation following a 15-day preculture without insulin, the dedifferentiated cells showed increased Acot1 expression with a diffuse distribution throughout the cytosol. These findings suggest that Acot1 expression is transiently upregulated at an early stage of adipocyte maturation, possibly to maintain cytosolic acyl-CoAs below a certain level until the cells acquire their full capability for fat storage.
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Affiliation(s)
- Takayuki Ohtomo
- Department of Pharmacotherapeutics, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
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16
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Fujita M, Momose A, Ohtomo T, Nishinosono A, Tanonaka K, Toyoda H, Morikawa M, Yamada J. Upregulation of fatty acyl-CoA thioesterases in the heart and skeletal muscle of rats fed a high-fat diet. Biol Pharm Bull 2011; 34:87-91. [PMID: 21212523 DOI: 10.1248/bpb.34.87] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In rodent models of diet-induced obesity, prolonged high-fat feeding increases the cellular uptake of fatty acids and causes lipotoxicity in the heart and skeletal muscle, where substrate overload to beta-oxidation generates mitochondrial stress. We examined the hypothesis that, because of its catalytic properties, acyl-CoA thioesterase (ACOT) would counteract these detrimental situations by modulating intracellular acyl-CoA levels. Rats were fed a low- or high-fat diet for up to 20 weeks, and the expressions of ACOT isoforms and fatty acid beta-oxidation enzymes were analyzed by western blotting. The expressions of ACOT1, ACOT2 and ACOT7 proteins in the heart and soleus muscle were significantly increased, by 2.0-7.6-fold, in rats fed the high-fat diet as compared with the low-fat diet group. These effects were accompanied by increases in carnitine palmitoyltransferase and acyl-CoA oxidase expression. However, ACOT was not induced in the extensor digitorum longus muscle or the liver. Subcellular fractionation of heart and soleus muscle homogenates confirmed expression of both the cytosolic and mitochondrial ACOT isoforms. These results underscore the functional relationship between ACOT and fatty acid oxidation, and suggest adaptive upregulation of ACOT to protect against fatty acid oversupply in the heart and skeletal muscle.
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Affiliation(s)
- Mariko Fujita
- Department of Clinical Biochemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192–0392, Japan
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17
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Kirkby B, Roman N, Kobe B, Kellie S, Forwood JK. Functional and structural properties of mammalian acyl-coenzyme A thioesterases. Prog Lipid Res 2010; 49:366-77. [PMID: 20470824 DOI: 10.1016/j.plipres.2010.04.001] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 04/23/2010] [Accepted: 04/26/2010] [Indexed: 10/19/2022]
Abstract
Acyl-coenzyme A thioesterases (Acots) play important cellular roles in mammalian fatty acid metabolism through modulation of cellular concentrations of activated fatty acyl-CoAs. Acots catalyse the hydrolysis of the thioester bond present within acyl-CoA ester molecules to yield coenzyme A (CoASH) and the corresponding non-esterified fatty acid. Acyl-CoA thioesterases are expressed ubiquitously in both prokaryotes and eukaryotes and, in higher order organisms, the enzymes are expressed and localised in a tissue-dependent manner within the cytosol, mitochondria, peroxisomes and endoplasmic reticulum. Recent studies have led to advances in the functional and structural characterization of many mammalian Acot family members. These include the structure determination of both type-I and type-II Acot family members, structural elucidation of the START domain of ACOT11, identification of roles in arachidonic acid and inflammatory prostaglandin production by Acot7, and inclusion of a 13th Acot family member. Here, we review and analyse the current literature on mammalian Acots with respect to their characterization and summarize the current knowledge on the structure, function and regulation of this enzyme family.
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Affiliation(s)
- Brenda Kirkby
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia
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18
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Overview of the pipeline for structural and functional characterization of macrophage proteins at the university of queensland. Methods Mol Biol 2008. [PMID: 18542891 DOI: 10.1007/978-1-60327-058-8_38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
This chapter describes the methodology adopted in a project aimed at structural and functional characterization of proteins that potentially play an important role in mammalian macrophages. The methodology that underpins this project is applicable to both small research groups and larger structural genomics consortia. Gene products with putative roles in macrophage function are identified using gene expression information obtained via DNA microarray technology. Specific targets for structural and functional characterization are then selected based on a set of criteria aimed at maximizing insight into function. The target proteins are cloned using a modification of Gateway cloning technology, expressed with hexa-histidine tags in E. coli, and purified to homogeneity using a combination of affinity and size exclusion chromatography. Purified proteins are finally subjected to crystallization trials and/or NMR-based screening to identify candidates for structure determination. Where crystallography and NMR approaches are unsuccessful, chemical cross-linking is employed to obtain structural information. This resulting structural information is used to guide cell biology experiments to further investigate the cellular and molecular function of the targets in macrophage biology. Jointly, the data sheds light on the molecular and cellular functions of macrophage proteins.
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19
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Forwood JK, Thakur AS, Guncar G, Marfori M, Mouradov D, Meng W, Robinson J, Huber T, Kellie S, Martin JL, Hume DA, Kobe B. Structural basis for recruitment of tandem hotdog domains in acyl-CoA thioesterase 7 and its role in inflammation. Proc Natl Acad Sci U S A 2007; 104:10382-7. [PMID: 17563367 PMCID: PMC1965522 DOI: 10.1073/pnas.0700974104] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Acyl-CoA thioesterases (Acots) catalyze the hydrolysis of fatty acyl-CoA to free fatty acid and CoA and thereby regulate lipid metabolism and cellular signaling. We present a comprehensive structural and functional characterization of mouse acyl-CoA thioesterase 7 (Acot7). Whereas prokaryotic homologues possess a single thioesterase domain, mammalian Acot7 contains a pair of domains in tandem. We determined the crystal structures of both the N- and C-terminal domains of the mouse enzyme, and inferred the structure of the full-length enzyme using a combination of chemical cross-linking, mass spectrometry, and molecular modeling. The quaternary arrangement in Acot7 features a trimer of hotdog fold dimers. Both domains of Acot7 are required for activity, but only one of two possible active sites in the dimer is functional. Asn-24 and Asp-213 (from N- and C-domains, respectively) were identified as the catalytic residues through site-directed mutagenesis. An enzyme with higher activity than wild-type Acot7 was obtained by mutating the residues in the nonfunctional active site. Recombinant Acot7 was shown to have the highest activity toward arachidonoyl-CoA, suggesting a function in eicosanoid metabolism. In line with the proposal, Acot7 was shown to be highly expressed in macrophages and up-regulated by lipopolysaccharide. Overexpression of Acot7 in a macrophage cell line modified the production of prostaglandins D2 and E2. Together, the results link the molecular and cellular functions of Acot7 and identify the enzyme as a candidate drug target in inflammatory disease.
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Affiliation(s)
- Jade K. Forwood
- *School of Molecular and Microbial Sciences
- To whom correspondence may be addressed. E-mail: or
| | | | - Gregor Guncar
- *School of Molecular and Microbial Sciences
- Institute for Molecular Bioscience
| | | | | | - Weining Meng
- *School of Molecular and Microbial Sciences
- Institute for Molecular Bioscience
| | - Jodie Robinson
- Institute for Molecular Bioscience
- Cooperative Research Centre for Chronic Inflammatory Diseases, and
| | | | - Stuart Kellie
- *School of Molecular and Microbial Sciences
- Institute for Molecular Bioscience
- Cooperative Research Centre for Chronic Inflammatory Diseases, and
| | - Jennifer L. Martin
- *School of Molecular and Microbial Sciences
- Institute for Molecular Bioscience
- **Australian Research Council Special Research Centre for Functional and Applied Genomics, University of Queensland, Brisbane, Queensland 4072, Australia
| | - David A. Hume
- *School of Molecular and Microbial Sciences
- Institute for Molecular Bioscience
- Cooperative Research Centre for Chronic Inflammatory Diseases, and
- **Australian Research Council Special Research Centre for Functional and Applied Genomics, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Bostjan Kobe
- *School of Molecular and Microbial Sciences
- Institute for Molecular Bioscience
- **Australian Research Council Special Research Centre for Functional and Applied Genomics, University of Queensland, Brisbane, Queensland 4072, Australia
- To whom correspondence may be addressed. E-mail: or
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20
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Maloberti P, Cornejo Maciel F, Castillo AF, Castilla R, Duarte A, Toledo MF, Meuli F, Mele P, Paz C, Podestá EJ. Enzymes involved in arachidonic acid release in adrenal and Leydig cells. Mol Cell Endocrinol 2007; 265-266:113-20. [PMID: 17207922 DOI: 10.1016/j.mce.2006.12.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Stimulation of receptors and subsequent signal transduction results in the activation of arachidonic acid (AA) release. Once AA is released from phospholipids or others esters, it may be metabolized via the cycloxygenase or the lipoxygenase pathways. How the cells drive AA to these pathways is not elucidated yet. It is reasonable to speculate that each pathway will have different sources of free AA triggered by different signal transduction pathways. Several reports have shown that AA and its lipoxygenase-catalyzed metabolites play essential roles in the regulation of steroidogenesis by influencing cholesterol transport from the outer to the inner mitochondrial membrane, the rate-limiting step in steroid hormone biosynthesis. Signals that stimulate steroidogenesis also cause the release of AA from phospholipids or other esters by mechanisms that are not fully understood. This review focuses on the enzymes of AA release that impact on steroidogenesis.
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Affiliation(s)
- P Maloberti
- Department of Biochemistry, School of Medicine, University of Buenos Aires, Paraguay 2155, 5 degrees (C1121ABG), Buenos Aires, Argentina
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21
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Ward NE, Pellis NR, Risin SA, Risin D. Gene expression alterations in activated human T-cells induced by modeled microgravity. J Cell Biochem 2006; 99:1187-202. [PMID: 16795038 DOI: 10.1002/jcb.20988] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Studies conducted in real Space and in ground-based microgravity analog systems (MAS) have demonstrated changes in numerous lymphocyte functions. In this investigation we explored whether the observed functional changes in lymphocytes in MAS are associated with changes in gene expression. NASA-developed Rotating Wall Vessel (RWV) bioreactor was utilized as a MAS. Activated T lymphocytes were obtained by adding 100 ng/ml of anti-CD3 and 100 U/ml of IL-2 in RPMI medium to blood donor mononuclear cells for 4 days. After that the cells were washed and additionally cultured for up to 2 weeks with media (RPMI, 10% FBS and 100 U/ml IL-2) replacement every 3-4 days. Flow cytometry analysis had proven that activated T lymphocytes were the only cells remaining in culture by that time. They were split into two portions, cultured for additional 24 h in either static or simulated microgravity conditions, and used for RNA extraction. The gene expression was assessed by Affymetrix GeneChip Human U133A array allowing screening for expression of 18,400 genes. About 4-8% of tested genes responded to MG by more than a 1.5-fold change in expression; however, reproducible changes were observed only in 89 genes. Ten of these genes were upregulated and 79 were downregulated. These genes were categorized by associated pathways and viewed graphically through histogram analysis. Separate histograms of each pathway were then constructed representing individual gene expression fold changes. Possible functional consequences of the identified reproducible gene expression changes are discussed.
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Hunt MC, Rautanen A, Westin MAK, Svensson LT, Alexson SEH. Analysis of the mouse and human acyl-CoA thioesterase (ACOT) gene clusters shows that convergent, functional evolution results in a reduced number of human peroxisomal ACOTs. FASEB J 2006; 20:1855-64. [PMID: 16940157 DOI: 10.1096/fj.06-6042com] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The maintenance of cellular levels of free fatty acids and acyl-CoAs, the activated form of free fatty acids, is extremely important, as imbalances in lipid metabolism have serious consequences for human health. Acyl-coenzyme A (CoA) thioesterases (ACOTs) hydrolyze acyl-CoAs to the free fatty acid and CoASH, and thereby have the potential to regulate intracellular levels of these compounds. We previously identified and characterized a mouse ACOT gene cluster comprised of six genes that apparently arose by gene duplications encoding acyl-CoA thioesterases with localizations in cytosol (ACOT1), mitochondria (ACOT2), and peroxisomes (ACOT3-6). However, the corresponding human gene cluster contains only three genes (ACOT1, ACOT2, and ACOT4) coding for full-length thioesterase proteins, of which only one is peroxisomal (ACOT4). We therefore set out to characterize the human genes, and we show here that the human ACOT4 protein catalyzes the activities of three mouse peroxisomal ACOTs (ACOT3, 4, and 5), being active on succinyl-CoA and medium to long chain acyl-CoAs, while ACOT1 and ACOT2 carry out similar functions to the corresponding mouse genes. These data strongly suggest that the human ACOT4 gene has acquired the functions of three mouse genes by a functional convergent evolution that also provides an explanation for the unexpectedly low number of human genes.
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Affiliation(s)
- Mary C Hunt
- Karolinska Institutet, Department of Laboratory Medicine, Division of Clinical Chemistry C1-74, Karolinska University Hospital at Huddinge, Stockhold SE-141 86, Sweden.
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23
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Takagi M, Ohtomo T, Hiratsuka K, Kuramochi Y, Suga T, Yamada J. Localization of a long-chain acyl-CoA hydrolase in spermatogenic cells in mice. Arch Biochem Biophys 2006; 446:161-6. [PMID: 16455042 DOI: 10.1016/j.abb.2005.12.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Revised: 12/14/2005] [Accepted: 12/23/2005] [Indexed: 12/01/2022]
Abstract
Brain acyl-CoA hydrolase (BACH) hydrolyzes long-chain acyl-CoAs to free fatty acids and CoA-SH. BACH is highly distributed in brain and is localized in neurons, but not glial cells. This suggests that BACH plays a specific role in neurons. BACH is also detected in testis, although the expression profile of BACH is unknown in testis. In this study, developmental changes and cellular distribution of BACH were examined in mouse testis. Before postnatal day (P) 10, BACH was detected at very low levels by Western blotting. Then, BACH content rapidly increased from P14 and reached maximum levels at P21, remaining high until at least P70. The increase in BACH content corresponded to the appearance of pachytene spermatocytes, which was confirmed by immunohistochemistry. BACH was also detectable in spermatids, but not in spermatogonia, mature spermatozoa. These results suggest that BACH is expressed in a cell-specific manner and plays a role in spermatogenesis.
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Affiliation(s)
- Mitsuhiro Takagi
- Laboratory of Clinical Biochemistry, Tokyo University of Pharmacy and Life Science, Tokyo, Japan.
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24
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Serek R, Forwood JK, Hume DA, Martin JL, Kobe B. Crystallization of the C-terminal domain of the mouse brain cytosolic long-chain acyl-CoA thioesterase. Acta Crystallogr Sect F Struct Biol Cryst Commun 2006; 62:133-5. [PMID: 16511283 PMCID: PMC2150959 DOI: 10.1107/s1744309106000030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Accepted: 01/03/2006] [Indexed: 11/11/2022]
Abstract
The mammalian long-chain acyl-CoA thioesterase, the enzyme that catalyses the hydrolysis of acyl-CoAs to free fatty acids, contains two fused 4HBT (4-hydroxybenzoyl-CoA thioesterase) motifs. The C-terminal domain of the mouse long-chain acyl-CoA thioesterase (Acot7) has been expressed in bacteria and crystallized. The crystals were obtained by vapour diffusion using PEG 2000 MME as precipitant at pH 7.0 and 290 K. The crystals have the symmetry of space group R32 (unit-cell parameters a = b = 136.83, c = 99.82 A, gamma = 120 degrees). Two molecules are expected in the asymmetric unit. The crystals diffract to 2.4 A resolution using the laboratory X-ray source and are suitable for crystal structure determination.
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Affiliation(s)
- Robert Serek
- School of Molecular and Microbial Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jade K. Forwood
- School of Molecular and Microbial Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - David A. Hume
- School of Molecular and Microbial Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
- Cooperative Research Centre for Chronic Inflammatory Diseases, University of Queensland, Brisbane, Queensland 4072, Australia
- Special Research Centre for Functional and Applied Genomics, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jennifer L. Martin
- School of Molecular and Microbial Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
- Special Research Centre for Functional and Applied Genomics, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Bostjan Kobe
- School of Molecular and Microbial Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
- Special Research Centre for Functional and Applied Genomics, University of Queensland, Brisbane, Queensland 4072, Australia
- Correspondence e-mail:
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Hunt MC, Yamada J, Maltais LJ, Wright MW, Podesta EJ, Alexson SEH. A revised nomenclature for mammalian acyl-CoA thioesterases/hydrolases. J Lipid Res 2005; 46:2029-32. [PMID: 16103133 DOI: 10.1194/jlr.e500003-jlr200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acyl-CoA thioesterases, also known as acyl-CoA hydrolases, are a group of enzymes that hydrolyze CoA esters such as acyl-CoAs (saturated, unsaturated, branched-chain), bile acid-CoAs, CoA esters of prostaglandins, etc., to the corresponding free acid and CoA. However, there is significant confusion regarding the nomenclature of these genes. In agreement with the HUGO Gene Nomenclature Committee and the Mouse Genomic Nomenclature Committee, a revised nomenclature for mammalian acyl-CoA thioesterases/hydrolases has been suggested for the 12 member family. The family root symbol is ACOT, with human genes named ACOT1-ACOT12, and rat and mouse genes named Acot1-Acot12. Several of the ACOT genes are the result of splicing events, and these splice variants are cataloged.
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Affiliation(s)
- Mary C Hunt
- Karolinska Institutet, Department of Laboratory Medicine, Division of Clinical Chemistry C1-74, Karolinska University Hospital at Huddinge, Stockholm, Sweden.
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