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Zaccaron AZ, Neill T, Corcoran J, Mahaffee WF, Stergiopoulos I. A chromosome-scale genome assembly of the grape powdery mildew pathogen Erysiphe necator reveals its genomic architecture and previously unknown features of its biology. mBio 2023; 14:e0064523. [PMID: 37341476 PMCID: PMC10470754 DOI: 10.1128/mbio.00645-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/13/2023] [Indexed: 06/22/2023] Open
Abstract
Erysiphe necator is an obligate fungal pathogen that causes grape powdery mildew, globally the most important disease on grapevines. Previous attempts to obtain a quality genome assembly for this pathogen were hindered by its high repetitive DNA content. Here, chromatin conformation capture (Hi-C) with long-read PacBio sequencing was combined to obtain a chromosome-scale assembly and a high-quality annotation for E. necator isolate EnFRAME01. The resulting 81.1 Mb genome assembly is 98% complete and consists of 34 scaffolds, 11 of which represent complete chromosomes. All chromosomes contain large centromeric-like regions and lack synteny to the 11 chromosomes of the cereal PM pathogen Blumeria graminis. Further analysis of their composition showed that repeats and transposable elements (TEs) occupy 62.7% of their content. TEs were almost evenly interspersed outside centromeric and telomeric regions and massively overlapped with regions of annotated genes, suggesting that they could have a significant functional impact. Abundant gene duplicates were observed as well, particularly in genes encoding candidate secreted effector proteins. Moreover, younger in age gene duplicates exhibited more relaxed selection pressure and were more likely to be located physically close in the genome than older duplicates. A total of 122 genes with copy number variations among six isolates of E. necator were also identified and were enriched in genes that were duplicated in EnFRAME01, indicating they may reflect an adaptive variation. Taken together, our study illuminates higher-order genomic architectural features of E. necator and provides a valuable resource for studying genomic structural variations in this pathogen. IMPORTANCE Grape powdery mildew caused by the ascomycete fungus Erysiphe necator is economically the most important and recurrent disease in vineyards across the world. The obligate biotrophic nature of E. necator hinders the use of typical genetic methods to elucidate its pathogenicity and adaptation to adverse conditions, and thus comparative genomics has been a major method to study its genome biology. However, the current reference genome of E. necator isolate C-strain is highly fragmented with many non-coding regions left unassembled. This incompleteness prohibits in-depth comparative genomic analyses and the study of genomic structural variations (SVs) that are known to affect several aspects of microbial life, including fitness, virulence, and host adaptation. By obtaining a chromosome-scale genome assembly and a high-quality gene annotation for E. necator, we reveal the organization of its chromosomal content, unearth previously unknown features of its biology, and provide a reference for studying genomic SVs in this pathogen.
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Affiliation(s)
- Alex Z. Zaccaron
- Department of Plant Pathology, University of California Davis, Davis, California, USA
| | - Tara Neill
- USDA-ARS, Horticultural Crops Disease and Pest Management Research Unit, Corvallis, Oregon, USA
| | - Jacob Corcoran
- USDA-ARS, Horticultural Crops Disease and Pest Management Research Unit, Corvallis, Oregon, USA
| | - Walter F. Mahaffee
- USDA-ARS, Horticultural Crops Disease and Pest Management Research Unit, Corvallis, Oregon, USA
| | - Ioannis Stergiopoulos
- Department of Plant Pathology, University of California Davis, Davis, California, USA
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Su CC, Lyu M, Zhang Z, Miyagi M, Huang W, Taylor DJ, Yu EW. High-resolution structural-omics of human liver enzymes. Cell Rep 2023; 42:112609. [PMID: 37289586 PMCID: PMC10592444 DOI: 10.1016/j.celrep.2023.112609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 03/28/2023] [Accepted: 05/20/2023] [Indexed: 06/10/2023] Open
Abstract
We applied raw human liver microsome lysate to a holey carbon grid and used cryo-electron microscopy (cryo-EM) to define its composition. From this sample we identified and simultaneously determined high-resolution structural information for ten unique human liver enzymes involved in diverse cellular processes. Notably, we determined the structure of the endoplasmic bifunctional protein H6PD, where the N- and C-terminal domains independently possess glucose-6-phosphate dehydrogenase and 6-phosphogluconolactonase enzymatic activity, respectively. We also obtained the structure of heterodimeric human GANAB, an ER glycoprotein quality-control machinery that contains a catalytic α subunit and a noncatalytic β subunit. In addition, we observed a decameric peroxidase, PRDX4, which directly contacts a disulfide isomerase-related protein, ERp46. Structural data suggest that several glycosylations, bound endogenous compounds, and ions associate with these human liver enzymes. These results highlight the importance of cryo-EM in facilitating the elucidation of human organ proteomics at the atomic level.
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Affiliation(s)
- Chih-Chia Su
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Meinan Lyu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Zhemin Zhang
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Masaru Miyagi
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Wei Huang
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Derek J Taylor
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Edward W Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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Li G, Li X, Yang L, Wang S, Dai Y, Fekry B, Veillon L, Tan L, Berdeaux R, Eckel-Mahan K, Lorenzi PL, Zhao Z, Lehner R, Sun K. Adipose tissue-specific ablation of Ces1d causes metabolic dysregulation in mice. Life Sci Alliance 2022; 5:e202101209. [PMID: 35459739 PMCID: PMC9034061 DOI: 10.26508/lsa.202101209] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 01/25/2023] Open
Abstract
Carboxylesterase 1d (Ces1d) is a crucial enzyme with a wide range of activities in multiple tissues. It has been reported to localize predominantly in ER. Here, we found that Ces1d levels are significantly increased in obese patients with type 2 diabetes. Intriguingly, a high level of Ces1d translocates onto lipid droplets where it digests the lipids to produce a unique set of fatty acids. We further revealed that adipose tissue-specific Ces1d knock-out (FKO) mice gained more body weight with increased fat mass during a high fat-diet challenge. The FKO mice exhibited impaired glucose and lipid metabolism and developed exacerbated liver steatosis. Mechanistically, deficiency of Ces1d induced abnormally large lipid droplet deposition in the adipocytes, causing ectopic accumulation of triglycerides in other peripheral tissues. Furthermore, loss of Ces1d diminished the circulating free fatty acids serving as signaling molecules to trigger the epigenetic regulations of energy metabolism via lipid-sensing transcriptional factors, such as HNF4α. The metabolic disorders induced an unhealthy microenvironment in the metabolically active tissues, ultimately leading to systemic insulin resistance.
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Affiliation(s)
- Gang Li
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Xin Li
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Li Yang
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Shuyue Wang
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Yulin Dai
- Center for Precision Health, School of Biomedical Informatics, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Baharan Fekry
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Lucas Veillon
- Metabolomic Core Facility, Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Lin Tan
- Metabolomic Core Facility, Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Rebecca Berdeaux
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center at Houston, Houston, TX, USA
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX, USA
- Program in Biochemistry and Cell Biology, MD Anderson Cancer Center-UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Kristin Eckel-Mahan
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center at Houston, Houston, TX, USA
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX, USA
- Program in Biochemistry and Cell Biology, MD Anderson Cancer Center-UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Philip L Lorenzi
- Metabolomic Core Facility, Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Zhongming Zhao
- Center for Precision Health, School of Biomedical Informatics, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Richard Lehner
- Group on Molecular and Cell Biology of Lipids, Department of Pediatrics, University of Alberta, Edmonton, Canada
| | - Kai Sun
- Center for Metabolic and Degenerative Diseases, The Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center at Houston, Houston, TX, USA
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX, USA
- Program in Biochemistry and Cell Biology, MD Anderson Cancer Center-UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA
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Lian J, van der Veen JN, Watts R, Jacobs RL, Lehner R. Carboxylesterase 1d (Ces1d) does not contribute to cholesteryl ester hydrolysis in the liver. J Lipid Res 2021; 62:100093. [PMID: 34153284 PMCID: PMC8287225 DOI: 10.1016/j.jlr.2021.100093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 06/09/2021] [Indexed: 01/19/2023] Open
Abstract
The liver is the central organ regulating cholesterol synthesis, storage, transport, and elimination. Mouse carboxylesterase 1d (Ces1d) and its human ortholog CES1 have been described to possess lipase activity and play roles in hepatic triacylglycerol metabolism and VLDL assembly. It has been proposed that Ces1d/CES1 might also catalyze cholesteryl ester (CE) hydrolysis in the liver and thus be responsible for the hydrolysis of HDL-derived CE; this could contribute to the final step in the reverse cholesterol transport (RCT) pathway, wherein cholesterol is secreted from the liver into bile and feces, either directly or after conversion to water-soluble bile salts. However, the proposed function of Ces1d/CES1 as a CE hydrolase is controversial. In this study, we interrogated the role hepatic Ces1d plays in cholesterol homeostasis using liver-specific Ces1d-deficient mice. We rationalized that if Ces1d is a major hepatic CE hydrolase, its absence would (1) reduce in vivo RCT flux and (2) provoke liver CE accumulation after a high-cholesterol diet challenge. We found that liver-specific Ces1d-deficient mice did not show any difference in the flux of in vivo HDL-to-feces RCT nor did it cause additional liver CE accumulation after high-fat, high-cholesterol Western-type diet feeding. These findings challenge the importance of Ces1d as a major hepatic CE hydrolase.
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Affiliation(s)
- Jihong Lian
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada.
| | - Jelske N van der Veen
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Russell Watts
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - René L Jacobs
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Richard Lehner
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada; Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada.
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Na K, Kim M, Kim CY, Lim JS, Cho JY, Shin H, Lee HJ, Kang BJ, Han DH, Kim H, Baik JH, Swiatek-de Lange M, Karl J, Paik YK. Potential Regulatory Role of Human-Carboxylesterase-1 Glycosylation in Liver Cancer Cell Growth. J Proteome Res 2020; 19:4867-4883. [PMID: 33206527 DOI: 10.1021/acs.jproteome.0c00787] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We previously reported that human carboxylesterase 1 (CES1), a serine esterase containing a unique N-linked glycosyl group at Asn79 (N79 CES1), is a candidate serological marker of hepatocellular carcinoma (HCC). CES1 is normally present at low-to-undetectable levels in normal human plasma, HCC tumors, and major liver cancer cell lines. To investigate the potential mechanism underlying the suppression of CES1 expression in liver cancer cells, we took advantage of the low detectability of this marker in tumors by overexpressing CES1 in multiple HCC cell lines, including stable Hep3B cells. We found that the population of CES1-overexpressing (OE) cells decreased and that their doubling time was longer compared with mock control liver cancer cells. Using interactive transcriptome, proteome, and subsequent Gene Ontology enrichment analysis of CES1-OE cells, we found substantial decreases in the expression levels of genes involved in cell cycle regulation and proliferation. This antiproliferative function of the N79 glycan of CES1 was further supported by quantitative real-time polymerase chain reaction, flow cytometry, and an apoptosis protein array assay. An analysis of the levels of key signaling target proteins via Western blotting suggested that CES1 overexpression exerted an antiproliferative effect via the PKD1/PKCμ signaling pathway. Similar results were also seen in another HCC cell line (PLC/RFP/5) after transient transfection with CES1 but not in similarly treated non-HCC cell lines (e.g., HeLa and Tera-1 cells), suggesting that CES1 likely exerts a liver cell-type-specific suppressive effect. Given that the N-linked glycosyl group at Asn79 (N79 glycan) of CES1 is known to influence CES1 enzyme activity, we hypothesized that the post-translational modification of CES1 at N79 may be linked to its antiproliferative activity. To investigate the regulatory effect of the N79 glycan on cellular growth, we mutated the single N-glycosylation site in CES1 from Asn to Gln (CES1-N79Q) via site-directed mutagenesis. Fluorescence 2-D difference gel electrophoresis protein expression analysis of cell lysates revealed an increase in cell growth and a decrease in doubling time in cells carrying the N79Q mutation. Thus our results suggest that CES1 exerts an antiproliferative effect in liver cancer cells and that the single N-linked glycosylation at Asn79 plays a potential regulatory role. These functions may underlie the undetectability of CES1 in human HCC tumors and liver cancer cell lines. Mass spectrometry data are available via ProteomeXchange under the identifier PXD021573.
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Affiliation(s)
- Keun Na
- Yonsei Proteome Research Center, Yonsei University, 50 Yonsei-ro, Seodaemoon-ku, Seoul 03722, South Korea
| | - Minjoo Kim
- Yonsei Proteome Research Center, Yonsei University, 50 Yonsei-ro, Seodaemoon-ku, Seoul 03722, South Korea
| | - Chae-Yeon Kim
- Yonsei Proteome Research Center, Yonsei University, 50 Yonsei-ro, Seodaemoon-ku, Seoul 03722, South Korea
| | - Jong-Sun Lim
- Yonsei Proteome Research Center, Yonsei University, 50 Yonsei-ro, Seodaemoon-ku, Seoul 03722, South Korea
| | - Jin-Young Cho
- Yonsei Proteome Research Center, Yonsei University, 50 Yonsei-ro, Seodaemoon-ku, Seoul 03722, South Korea
| | - Heon Shin
- Yonsei Proteome Research Center, Yonsei University, 50 Yonsei-ro, Seodaemoon-ku, Seoul 03722, South Korea
| | - Hyo Jin Lee
- Department of Life Sciences, Korea University, 145 Anamro, Seongbuk-ku, Seoul 02841, South Korea
| | - Byeong Jun Kang
- Department of Life Sciences, Korea University, 145 Anamro, Seongbuk-ku, Seoul 02841, South Korea
| | | | | | - Ja-Hyun Baik
- Department of Life Sciences, Korea University, 145 Anamro, Seongbuk-ku, Seoul 02841, South Korea
| | | | - Johann Karl
- Roche Diagnostics, GmbH, Nonnenwald 2, 82377 Penzberg, Germany
| | - Young-Ki Paik
- Yonsei Proteome Research Center, Yonsei University, 50 Yonsei-ro, Seodaemoon-ku, Seoul 03722, South Korea
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Human carboxylesterases: a comprehensive review. Acta Pharm Sin B 2018; 8:699-712. [PMID: 30245959 PMCID: PMC6146386 DOI: 10.1016/j.apsb.2018.05.005] [Citation(s) in RCA: 282] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 05/07/2018] [Accepted: 05/09/2018] [Indexed: 12/12/2022] Open
Abstract
Mammalian carboxylesterases (CEs) are key enzymes from the serine hydrolase superfamily. In the human body, two predominant carboxylesterases (CES1 and CES2) have been identified and extensively studied over the past decade. These two enzymes play crucial roles in the metabolism of a wide variety of endogenous esters, ester-containing drugs and environmental toxicants. The key roles of CES in both human health and xenobiotic metabolism arouse great interest in the discovery of potent CES modulators to regulate endobiotic metabolism or to improve the efficacy of ester drugs. This review covers the structural and catalytic features of CES, tissue distributions, biological functions, genetic polymorphisms, substrate specificities and inhibitor properties of CES1 and CES2, as well as the significance and recent progress on the discovery of CES modulators. The information presented here will help pharmacologists explore the relevance of CES to human diseases or to assign the contribution of certain CES in xenobiotic metabolism. It will also facilitate medicinal chemistry efforts to design prodrugs activated by a given CES isoform, or to develop potent and selective modulators of CES for potential biomedical applications.
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Lian J, Nelson R, Lehner R. Carboxylesterases in lipid metabolism: from mouse to human. Protein Cell 2017; 9:178-195. [PMID: 28677105 PMCID: PMC5818367 DOI: 10.1007/s13238-017-0437-z] [Citation(s) in RCA: 155] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 05/31/2017] [Indexed: 12/12/2022] Open
Abstract
Mammalian carboxylesterases hydrolyze a wide range of xenobiotic and endogenous compounds, including lipid esters. Physiological functions of carboxylesterases in lipid metabolism and energy homeostasis in vivo have been demonstrated by genetic manipulations and chemical inhibition in mice, and in vitro through (over)expression, knockdown of expression, and chemical inhibition in a variety of cells. Recent research advances have revealed the relevance of carboxylesterases to metabolic diseases such as obesity and fatty liver disease, suggesting these enzymes might be potential targets for treatment of metabolic disorders. In order to translate pre-clinical studies in cellular and mouse models to humans, differences and similarities of carboxylesterases between mice and human need to be elucidated. This review presents and discusses the research progress in structure and function of mouse and human carboxylesterases, and the role of these enzymes in lipid metabolism and metabolic disorders.
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Affiliation(s)
- Jihong Lian
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada. .,Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada.
| | - Randal Nelson
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada.,Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Richard Lehner
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada.,Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada.,Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
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Oh J, Lee S, Lee H, Cho JY, Yoon SH, Jang IJ, Yu KS, Lim KS. The novel carboxylesterase 1 variant c.662A>G may decrease the bioactivation of oseltamivir in humans. PLoS One 2017; 12:e0176320. [PMID: 28437488 PMCID: PMC5402961 DOI: 10.1371/journal.pone.0176320] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 04/07/2017] [Indexed: 11/18/2022] Open
Abstract
Background Human carboxylesterase 1 (CES1) is a serine esterase that hydrolyses various exogenous and endogenous compounds including oseltamivir, a prodrug used to treat influenza. A novel CES1 c.662A>G single nucleotide polymorphism (SNP) was predicted to decrease CES1 enzymatic activity in an in silico analysis. This study evaluated the effect of the c.662A>G SNP on the pharmacokinetics (PK) of oseltamivir in humans. Methods A single oral dose of oseltamivir at 75 mg was administered to 20 healthy subjects, 8 heterozygous c.662A>G carriers (c.662AG) and 12 non-carriers (c.662AA). The concentrations of oseltamivir and its active metabolite, oseltamivir carboxylate, were measured in plasma and urine using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The PK parameters were calculated using a noncompartmental method. The geometric mean ratios (GMR, c.662AG to c.662AA) of the PK parameters and their 90% confidence intervals (CI) were calculated. Results The systemic exposure to oseltamivir, as assessed by the AUC0-48h of oseltamivir, was increased by 10% in c.662AG subjects, whereas the AUC0-48h of oseltamivir carboxylate was 5% lower in c.662AG subjects. The GMR and 90% CI of the metabolic ratio (AUC0-48h, Oseltamivir carboxylate/AUC0-48h, Oseltamivir) was 0.87 (0.66–1.14). The amount of unchanged oseltamivir excreted in the urine was increased by 15% in subjects with the c.662AG genotype. Conclusions This result suggests that CES1 enzymatic activity may be decreased in these heterozygous allele carriers, although further studies are warranted to investigate the clinical implications of this genetic variation on CES1 substrate drugs. Trial registration ClinicalTtrials.gov NCT01902342
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Affiliation(s)
- Jaeseong Oh
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Republic of Korea
| | - SeungHwan Lee
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Republic of Korea
| | - Howard Lee
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Republic of Korea
- Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
| | - Joo-Youn Cho
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Republic of Korea
| | - Seo Hyun Yoon
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Republic of Korea
| | - In-Jin Jang
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Republic of Korea
| | - Kyung-Sang Yu
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Republic of Korea
| | - Kyoung Soo Lim
- Department of Clinical Pharmacology and Therapeutics, CHA University School of Medicine and CHA Bundang Medical Center, Seongnam, Republic of Korea
- * E-mail:
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Vandemoortele G, Gevaert K, Eyckerman S. Proteomics in the genome engineering era. Proteomics 2015; 16:177-87. [DOI: 10.1002/pmic.201500262] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 09/22/2015] [Accepted: 10/15/2015] [Indexed: 12/13/2022]
Affiliation(s)
- Giel Vandemoortele
- VIB Medical Biotechnology Center; Ghent Belgium
- Department of Biochemistry; Ghent University; Ghent Belgium
| | - Kris Gevaert
- VIB Medical Biotechnology Center; Ghent Belgium
- Department of Biochemistry; Ghent University; Ghent Belgium
| | - Sven Eyckerman
- VIB Medical Biotechnology Center; Ghent Belgium
- Department of Biochemistry; Ghent University; Ghent Belgium
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Arena de Souza V, Scott DJ, Nettleship JE, Rahman N, Charlton MH, Walsh MA, Owens RJ. Comparison of the Structure and Activity of Glycosylated and Aglycosylated Human Carboxylesterase 1. PLoS One 2015; 10:e0143919. [PMID: 26657071 PMCID: PMC4676782 DOI: 10.1371/journal.pone.0143919] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 11/11/2015] [Indexed: 11/25/2022] Open
Abstract
Human Carboxylesterase 1 (hCES1) is the key liver microsomal enzyme responsible for detoxification and metabolism of a variety of clinical drugs. To analyse the role of the single N-linked glycan on the structure and activity of the enzyme, authentically glycosylated and aglycosylated hCES1, generated by mutating asparagine 79 to glutamine, were produced in human embryonic kidney cells. Purified enzymes were shown to be predominantly trimeric in solution by analytical ultracentrifugation. The purified aglycosylated enzyme was found to be more active than glycosylated hCES1 and analysis of enzyme kinetics revealed that both enzymes exhibit positive cooperativity. Crystal structures of hCES1 a catalytically inactive mutant (S221A) and the aglycosylated enzyme were determined in the absence of any ligand or substrate to high resolutions (1.86 Å, 1.48 Å and 2.01 Å, respectively). Superposition of all three structures showed only minor conformational differences with a root mean square deviations of around 0.5 Å over all Cα positions. Comparison of the active sites of these un-liganded enzymes with the structures of hCES1-ligand complexes showed that side-chains of the catalytic triad were pre-disposed for substrate binding. Overall the results indicate that preventing N-glycosylation of hCES1 does not significantly affect the structure or activity of the enzyme.
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Affiliation(s)
- Victoria Arena de Souza
- UK OPPF-UK, The Research Complex at Harwell, Rutherford Appleton Laboratory Harwell Oxford, Oxfordshire, United Kingdom
- Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford, United Kingdom
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, United Kingdom
| | - David J. Scott
- The Research Complex at Harwell, Rutherford Appleton Laboratory Harwell Oxford, Oxfordshire, United Kingdom
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Sutton Bonington, Leicestershire, United Kingdom
| | - Joanne E. Nettleship
- UK OPPF-UK, The Research Complex at Harwell, Rutherford Appleton Laboratory Harwell Oxford, Oxfordshire, United Kingdom
- Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford, United Kingdom
| | - Nahid Rahman
- UK OPPF-UK, The Research Complex at Harwell, Rutherford Appleton Laboratory Harwell Oxford, Oxfordshire, United Kingdom
- Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford, United Kingdom
| | - Michael H. Charlton
- Chroma Therapeutics Ltd., 93 Innovation Drive Milton Park, Abingdon, United Kingdom
| | - Martin A. Walsh
- The Research Complex at Harwell, Rutherford Appleton Laboratory Harwell Oxford, Oxfordshire, United Kingdom
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, United Kingdom
- * E-mail: (MAW); (RJO)
| | - Raymond J. Owens
- UK OPPF-UK, The Research Complex at Harwell, Rutherford Appleton Laboratory Harwell Oxford, Oxfordshire, United Kingdom
- Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Roosevelt Drive, Oxford, United Kingdom
- * E-mail: (MAW); (RJO)
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Eichmann TO, Lass A. DAG tales: the multiple faces of diacylglycerol--stereochemistry, metabolism, and signaling. Cell Mol Life Sci 2015; 72:3931-52. [PMID: 26153463 PMCID: PMC4575688 DOI: 10.1007/s00018-015-1982-3] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 06/17/2015] [Accepted: 06/29/2015] [Indexed: 12/31/2022]
Abstract
The neutral lipids diacylglycerols (DAGs) are involved in a plethora of metabolic pathways. They function as components of cellular membranes, as building blocks for glycero(phospho)lipids, and as lipid second messengers. Considering their central role in multiple metabolic processes and signaling pathways, cellular DAG levels require a tight regulation to ensure a constant and controlled availability. Interestingly, DAG species are versatile in their chemical structure. Besides the different fatty acid species esterified to the glycerol backbone, DAGs can occur in three different stereo/regioisoforms, each with unique biological properties. Recent scientific advances have revealed that DAG metabolizing enzymes generate and distinguish different DAG isoforms, and that only one DAG isoform holds signaling properties. Herein, we review the current knowledge of DAG stereochemistry and their impact on cellular metabolism and signaling. Further, we describe intracellular DAG turnover and its stereochemistry in a 3-pool model to illustrate the spatial and stereochemical separation and hereby the diversity of cellular DAG metabolism.
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Affiliation(s)
- Thomas Oliver Eichmann
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31/2, 8010, Graz, Austria.
| | - Achim Lass
- Institute of Molecular Biosciences, University of Graz, Heinrichstrasse 31/2, 8010, Graz, Austria.
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13
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Coleman RA, Mashek DG. Mammalian triacylglycerol metabolism: synthesis, lipolysis, and signaling. Chem Rev 2011; 111:6359-86. [PMID: 21627334 PMCID: PMC3181269 DOI: 10.1021/cr100404w] [Citation(s) in RCA: 206] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Rosalind A Coleman
- Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
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14
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15
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Quiroga AD, Lehner R. Role of endoplasmic reticulum neutral lipid hydrolases. Trends Endocrinol Metab 2011; 22:218-25. [PMID: 21531146 DOI: 10.1016/j.tem.2011.03.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 03/12/2011] [Accepted: 03/16/2011] [Indexed: 01/19/2023]
Abstract
Lipid droplets are universal intracellular organelles composed of a triglyceride, cholesteryl ester and retinyl ester core, surrounded by a monolayer of phospholipids and free (unesterified) cholesterol and lipid droplet-associated proteins. Core lipids are hydrolyzed by lipases to provide fatty acids, cholesterol and retinol for various cellular functions. In addition to cytosolic adipose triglyceride lipase and hormone-sensitive lipase, recent studies show the existence of other neutral lipid hydrolases that reside in the endoplasmic reticulum. In this review we highlight the role of these novel lipases including several members of the carboxylesterase family and enzymes termed arylacetamide deacetylase and KIAA1363/neutral cholesteryl ester hydrolase1/arylacetamide deacetylase-like 1. Some of these enzymes might be attractive targets for the treatment of dyslipidemias, viral infection and atherosclerosis.
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Affiliation(s)
- Ariel D Quiroga
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
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16
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Current approaches for engineering proteins with diverse biological properties. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 620:18-33. [PMID: 18217332 DOI: 10.1007/978-0-387-76713-0_2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
In the past two decades, protein engineering has advanced significantly with the emergence of new chemical and genetic approaches. Modification and recombination of existing proteins not only produced novel enzymes used commercially and in research laboratories, but furthermore, they revealed the mechanisms of protein function. In this chapter, we will describe the applications and significance of current protein engineering approaches.
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17
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Hosokawa M. Structure and catalytic properties of carboxylesterase isozymes involved in metabolic activation of prodrugs. Molecules 2008; 13:412-31. [PMID: 18305428 PMCID: PMC6245361 DOI: 10.3390/molecules13020412] [Citation(s) in RCA: 286] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 02/09/2008] [Accepted: 02/11/2008] [Indexed: 11/20/2022] Open
Abstract
Mammalian carboxylesterases (CESs) comprise a multigene family whose gene products play important roles in biotransformation of ester- or amide-type prodrugs. They are members of an α,β-hydrolase-fold family and are found in various mammals. It has been suggested that CESs can be classified into five major groups denominated CES1-CES5, according to the homology of the amino acid sequence, and the majority of CESs that have been identified belong to the CES1 or CES2 family. The substrate specificities of CES1 and CES2 are significantly different. The CES1 isozyme mainly hydrolyzes a substrate with a small alcohol group and large acyl group, but its wide active pocket sometimes allows it to act on structurally distinct compounds of either a large or small alcohol moiety. In contrast, the CES2 isozyme recognizes a substrate with a large alcohol group and small acyl group, and its substrate specificity may be restricted by the capability of acyl-enzyme conjugate formation due to the presence of conformational interference in the active pocket. Since pharmacokinetic and pharmacological data for prodrugs obtained from preclinical experiments using various animals are generally used as references for human studies, it is important to clarify the biochemical properties of CES isozymes. Further experimentation for an understanding of detailed substrate specificity of prodrugs for CES isozymes and its hydrolysates will help us to design the ideal prodrugs.
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Affiliation(s)
- Masakiyo Hosokawa
- Laboratory of Drug Metabolism and Biopharmaceutics, Faculty of Pharmaceutical Sciences, Chiba Institute of Science, Shiomi-Cho, Choshi-City, Chiba 288-0025, Japan.
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18
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Hosokawa M, Furihata T, Yaginuma Y, Yamamoto N, Koyano N, Fujii A, Nagahara Y, Satoh T, Chiba K. Genomic structure and transcriptional regulation of the rat, mouse, and human carboxylesterase genes. Drug Metab Rev 2007; 39:1-15. [PMID: 17364878 DOI: 10.1080/03602530600952164] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The mammalian carboxylesterases (CESs) comprise a multigene family which gene products play important roles in biotransformation of ester- or amide-type prodrugs. Since expression level of CESs may affect the pharmacokinetic behavior of prodrugs in vivo, it is important to understand the transcriptional regulation mechanism of the CES genes. However, little is known about the gene structure and transcriptional regulation of the mammalian CES genes. In the present study, to investigate the transcriptional regulation of the promoter region of the CES1 and CES2 genes were isolated from mouse, rat and human genomic DNA by PCR amplification. A TATA box was not found the transcriptional start site of all CES promoter. These CES promoters share several common binding sites for transcription factors among the same CES families, suggesting that the orthologous CES genes have evolutionally conserved transcriptional regulatory mechanisms. The result of present study suggested that the mammalian CES promoters were at least partly conserved among the same CES families, and some of the transcription factors may play similar roles in transcriptional regulation of the human and murine CES genes.
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Affiliation(s)
- Masakiyo Hosokawa
- Faculty of Pharmaceutical Sciences, Chiba Institute of Sciences, Choshi, 288-0025, Japan.
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19
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Wei E, Gao W, Lehner R. Attenuation of Adipocyte Triacylglycerol Hydrolase Activity Decreases Basal Fatty Acid Efflux. J Biol Chem 2007; 282:8027-35. [PMID: 17237500 DOI: 10.1074/jbc.m605789200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fatty acids released from adipose triacylglycerol stores by lipolysis provide vertebrates with an important source of energy. We investigated the role of microsomal triacylglycerol hydrolase (TGH) in the mobilization of adipocyte triacylglycerols through inactivation of the TGH activity by RNA interference or chemical inhibition. Attenuation of TGH activity resulted in decreased basal but not isoproterenol-stimulated efflux of fatty acids from 3T3-L1 adipocytes. Lack of TGH activity was accompanied by accumulation of cellular triacylglycerols and cholesteryl esters without any changes in the expression of enzymes catalyzing triacylglycerol synthesis (diacylglycerol acyltransferases 1 and 2) or degradation (adipose triglyceride lipase and hormone-sensitive lipase). Inhibition of TGH-mediated lipolysis also did not affect insulin-stimulated Glut4 translocation from intracellular compartments to the plasma membrane or glucose uptake into adipocytes. These data suggest that TGH plays a role in adipose tissue triacylglycerol metabolism and may be a suitable pharmacological target for lowering fatty acid efflux from adipose tissue without altering glucose import.
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Affiliation(s)
- Enhui Wei
- Department of Pediatrics, Canadian Institutes of Health Research Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
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20
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Kolkenbrock S, Parschat K, Beermann B, Hinz HJ, Fetzner S. N-acetylanthranilate amidase from Arthrobacter nitroguajacolicus Rü61a, an alpha/beta-hydrolase-fold protein active towards aryl-acylamides and -esters, and properties of its cysteine-deficient variant. J Bacteriol 2006; 188:8430-40. [PMID: 17041061 PMCID: PMC1698245 DOI: 10.1128/jb.01085-06] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
N-acetylanthranilate amidase (Amq), a 32.8-kDa monomeric amide hydrolase, is involved in quinaldine degradation by Arthrobacter nitroguajacolicus Rü61a. Sequence analysis and secondary structure predictions indicated that Amq is related to carboxylesterases and belongs to the alpha/beta-hydrolase-fold superfamily of enzymes; inactivation of (His(6)-tagged) Amq by phenylmethanesulfonyl fluoride and diethyl pyrocarbonate and replacement of conserved residues suggested a catalytic triad consisting of S155, E235, and H266. Amq is most active towards aryl-acetylamides and aryl-acetylesters. Remarkably, its preference for ring-substituted analogues was different for amides and esters. Among the esters tested, phenylacetate was hydrolyzed with highest catalytic efficiency (k(cat)/K(m) = 208 mM(-1) s(-1)), while among the aryl-acetylamides, o-carboxy- or o-nitro-substituted analogues were preferred over p-substituted or unsubstituted compounds. Hydrolysis by His(6)Amq of primary amides, lactams, N-acetylated amino acids, azocoll, tributyrin, and the acylanilide and urethane pesticides propachlor, propham, carbaryl, and isocarb was not observed; propanil was hydrolyzed with 1% N-acetylanthranilate amidase activity. The catalytic properties of the cysteine-deficient variant His(6)AmqC22A/C63A markedly differed from those of His(6)Amq. The replacements effected some changes in K(m)s of the enzyme and increased k(cat)s for most aryl-acetylesters and some aryl-acetylamides by factors of about three to eight while decreasing k(cat) for the formyl analogue N-formylanthranilate by several orders of magnitude. Circular dichroism studies indicated that the cysteine-to-alanine replacements resulted in significant change of the overall fold, especially an increase in alpha-helicity of the cysteine-deficient protein. The conformational changes may also affect the active site and may account for the observed changes in kinetic properties.
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Affiliation(s)
- Stephan Kolkenbrock
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 3, D-48149 Münster, Germany
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21
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Okazaki H, Igarashi M, Nishi M, Tajima M, Sekiya M, Okazaki S, Yahagi N, Ohashi K, Tsukamoto K, Amemiya-Kudo M, Matsuzaka T, Shimano H, Yamada N, Aoki J, Morikawa R, Takanezawa Y, Arai H, Nagai R, Kadowaki T, Osuga JI, Ishibashi S. Identification of a novel member of the carboxylesterase family that hydrolyzes triacylglycerol: a potential role in adipocyte lipolysis. Diabetes 2006; 55:2091-7. [PMID: 16804080 DOI: 10.2337/db05-0585] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Molecular mechanisms underlying lipolysis, as defined by mobilization of fatty acids from adipose tissue, are not fully understood. A database search for enzymes with alpha/beta hydrolase folds, the GXSXG motif for serine esterase and the His-Gly dipeptide motif, has provided a previously unannotated gene that is induced during 3T3-L1 adipocytic differentiation. Because of its remarkable structural resemblance to triacylglycerol hydrolase (TGH) with 70.4% identity, we have tentatively designated this enzyme as TGH-2 and the original TGH as TGH-1. TGH-2 is also similar to TGH-1 in terms of tissue distribution, subcellular localization, substrate specificity, and regulation. Both enzymes are predominantly expressed in liver, adipose tissue, and kidney. In adipocytes, they are localized in microsome and fatcake. Both enzymes hydrolyzed p-nitophenyl butyrate, triolein, and monoolein but not diolein, cholesteryl oleate, or phospholipids; hydrolysis of short-chain fatty acid ester was 30,000-fold more efficient than that of long-chain fatty acid triacylglycerol. Fasting increased the expression of both genes in white adipose tissue, whereas refeeding suppressed their expression. RNA silencing of TGH-2 reduced isoproterenol-stimulated glycerol release by 10% in 3T3-L1 adipocytes, while its overexpression increased the glycerol release by 20%. Thus, TGH-2 may make a contribution to adipocyte lipolysis during period of increased energy demand.
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Affiliation(s)
- Hiroaki Okazaki
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.
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22
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Alam M, Gilham D, Vance DE, Lehner R. Mutation of F417 but not of L418 or L420 in the lipid binding domain decreases the activity of triacylglycerol hydrolase. J Lipid Res 2005; 47:375-83. [PMID: 16282638 DOI: 10.1194/jlr.m500344-jlr200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human triacylglycerol hydrolase (hTGH) has been shown to play a role in hepatic lipid metabolism. Triacylglycerol hydrolase (TGH) hydrolyzes insoluble carboxylic esters at lipid/water interfaces, although the mechanism by which the enzyme adsorbs to lipid droplets is unclear. Three-dimensional modeling of hTGH predicts that catalytic residues are adjacent to an alpha-helix that may mediate TGH/lipid interaction. The helix contains a putative neutral lipid binding domain consisting of the octapeptide FLDLIADV (amino acid residues 417-424) with the consensus sequence FLXLXXXn (where n is a nonpolar residue and X is any amino acid except proline) identified in several other proteins that bind or metabolize neutral lipids. Deletion of this alpha-helix abolished the lipolytic activity of hTGH. Replacement of F417 with alanine reduced activity by 40% toward both insoluble and soluble esters, whereas replacement of L418 and L420 with alanine did not. Another potential mechanism of increasing TGH affinity for lipid is via reversible acylation. Molecular modeling predicts that C390 is available for covalent acylation. However, neither chemical modification of C390 nor mutation to alanine affected activity. Our findings indicate that F417 but not L418, L420, or C390 participates in substrate hydrolysis by hTGH.
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Affiliation(s)
- Mustafa Alam
- Department of Pediatrics, Canadian Institutes of Health Research Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
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23
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Gilham D, Perreault KR, Holmes CFB, Brindley DN, Vance DE, Lehner R. Insulin, glucagon and fatty acid treatment of hepatocytes does not result in phosphorylation or changes in activity of triacylglycerol hydrolase. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1736:189-99. [PMID: 16168708 DOI: 10.1016/j.bbalip.2005.08.013] [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] [Received: 03/01/2005] [Revised: 07/19/2005] [Accepted: 08/09/2005] [Indexed: 10/25/2022]
Abstract
It is recognized that the majority of very low density lipoprotein (VLDL) associated triacylglycerol (TG) is synthesized from fatty acids and partial acylglycerols generated by lipolysis of intra-hepatic storage rather than made de novo. Triacylglycerol hydrolase (TGH) is involved in mobilizing stored TG. Modulating the ability of TGH to hydrolyze stored lipids represents a potentially regulated and rate limiting step in VLDL assembly. Phosphorylation of lipases and carboxylesterases trigger diverse but functionally significant events. We explored the potential for regulating the mobilization of hepatic TG through phosphorylation of TGH. Insulin is known to suppress VLDL secretion from liver, and glucagon can be considered an opposing hormone. However, neither insulin nor glucagon treatment of hepatocytes led to phosphorylation of TGH or changes in its activity. Augmenting intracellular TG stores by incubations with oleic acid also did not lead to changes in TGH activity. Therefore, changes in phosphorylation state are not a mechanism for regulating TGH activity, access to TG substrate pools or for TGH-mediated contributions to VLDL assembly and secretion.
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Affiliation(s)
- Dean Gilham
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
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24
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tom Dieck H, Döring F, Fuchs D, Roth HP, Daniel H. Transcriptome and proteome analysis identifies the pathways that increase hepatic lipid accumulation in zinc-deficient rats. J Nutr 2005; 135:199-205. [PMID: 15671213 DOI: 10.1093/jn/135.2.199] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
For identification of the underlying molecular changes in hepatic lipid metabolism in zinc deficiency, rats were force-fed a zinc-deficient diet. Subsequently DNA-microarray and proteome profiling was performed in combination with hepatic lipid analysis. Of 6200 target sequences analyzed, 268 transcripts showed altered expression levels in livers of zinc-deficient rats, with 43 genes thereof related to hepatic lipid metabolism. Northern blot analysis and quantitative real-time RT-PCR were employed to confirm changes in mRNA levels. Proteins involved in lipid metabolism were identified by proteome analysis. Functional gene clusters with uniform changes in transcript levels suggested that the pathways required for lipolysis and mitochondrial as well as peroxisomal fatty acid degradation were downregulated, whereas those needed for de novo fatty acid synthesis and triglyceride assembly were increased. Subsequent enzymatic analysis of liver tissues confirmed an almost 40% greater triacylglycerol concentration in zinc-depleted rats, as well as an altered fatty acid composition of the lipid fraction as determined by gas chromatography. Liver lipids of zinc-deficient rats had significantly greater proportions of cis-9-oleic acid, cis-11-vaccenic acid, caprylic acid, myristic acid, alpha-linolenic acid, and eicosapentaenoic acid, and significantly less stearic and arachidonic acids. These alterations in hepatic metabolism are discussed in the context of changes in mRNA and protein levels of enzymes and transporters responsible for fatty acid metabolism, sequestration, and their transcriptional control.
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Affiliation(s)
- Heike tom Dieck
- Degussa Food Ingredients GmbH, Lise-Meitner-Strasse 34, 85354 Freising, Germany
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25
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Gilham D, Alam M, Gao W, Vance DE, Lehner R. Triacylglycerol hydrolase is localized to the endoplasmic reticulum by an unusual retrieval sequence where it participates in VLDL assembly without utilizing VLDL lipids as substrates. Mol Biol Cell 2004; 16:984-96. [PMID: 15601899 PMCID: PMC545928 DOI: 10.1091/mbc.e04-03-0224] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The majority of hepatic intracellular triacylglycerol (TG) is mobilized by lipolysis followed by reesterification to reassemble TG before incorporation into a very-low-density lipoprotein (VLDL) particle. Triacylglycerol hydrolase (TGH) is a lipase that hydrolyzes TG within hepatocytes. Immunogold electron microscopy in transfected cells revealed a disparate distribution of this enzyme within the endoplasmic reticulum (ER), with particularly intense localization in regions surrounding mitochondria. TGH is localized to the lumen of the ER by the C-terminal tetrapeptide sequence HIEL functioning as an ER retention signal. Deletion of HIEL resulted in secretion of catalytically active TGH. Mutation of HIEL to KDEL, which is the consensus ER retrieval sequence in animal cells, also resulted in ER retention and conservation of lipolytic activity. However, KDEL-TGH was not as efficient at mobilizing lipids for VLDL secretion and exhibited an altered distribution within the ER. TGH is a glycoprotein, but glycosylation is not required for catalytic activity. TGH does not hydrolyze apolipoprotein B-associated lipids. This suggests a mechanism for vectored movement of TGs onto developing VLDL in the ER as TGH may mobilize TG for VLDL assembly, but will not access this lipid once it is associated with VLDL.
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Affiliation(s)
- Dean Gilham
- Department of Cell Biology, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
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26
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Lichtman AH, Leung D, Shelton CC, Saghatelian A, Hardouin C, Boger DL, Cravatt BF. Reversible Inhibitors of Fatty Acid Amide Hydrolase That Promote Analgesia: Evidence for an Unprecedented Combination of Potency and Selectivity. J Pharmacol Exp Ther 2004; 311:441-8. [PMID: 15229230 DOI: 10.1124/jpet.104.069401] [Citation(s) in RCA: 282] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fatty acid amide hydrolase (FAAH) is the primary catabolic regulator of several bioactive lipid amides in vivo, including the endogenous cannabinoid anandamide and the sleep-inducing substance oleamide. Inhibitors of FAAH are considered a potential therapeutic approach for the treatment of several nervous system disorders, including pain, anxiety, and insomnia. However, for FAAH inhibitors to achieve clinical utility, they must not only display efficacy in vivo but also selectivity for this enzyme relative to the numerous other serine hydrolases present in mammalian proteomes. Here, we report a general strategy for evaluating the pharmacological activity and target specificity of FAAH inhibitors and its implementation to develop the first class of selective reversible inhibitors of this enzyme that are highly efficacious in vivo. Using a series of functional proteomics, analytical chemistry, and behavioral pharmacology assays, we have identified a class of alpha-keto-heterocycles that show unprecedented selectivity for FAAH relative to other mammalian hydrolases, and, when administered to rodents, raise central nervous system levels of anandamide and promote cannabinoid receptor 1-dependent analgesia in several assays of pain sensation. These studies provide further evidence that FAAH may represent an attractive therapeutic target and describe a general route by which inhibitors of this enzyme can be optimized to achieve exceptional potency, selectivity, and efficacy in vivo.
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Affiliation(s)
- Aron H Lichtman
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, P.O. Box 980613, Richmond, VA 23298-0613, USA.
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27
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Dolinsky VW, Gilham D, Hatch GM, Agellon LB, Lehner R, Vance DE. Regulation of triacylglycerol hydrolase expression by dietary fatty acids and peroxisomal proliferator-activated receptors. Biochim Biophys Acta Mol Cell Biol Lipids 2004; 1635:20-8. [PMID: 14642773 DOI: 10.1016/j.bbalip.2003.09.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Triacylglycerol hydrolase (TGH) is an enzyme that catalyzes the lipolysis of intracellular stored triacylglycerol (TG). Peroxisomal proliferator-activated receptors (PPAR) regulate a multitude of genes involved in lipid homeostasis. Polyunsaturated fatty acids (PUFA) are PPAR ligands and fatty acids are produced via TGH activity, so we studied whether dietary fats and PPAR agonists could regulate TGH expression. In 3T3-L1 adipocytes, TGH expression was increased 10-fold upon differentiation, compared to pre-adipocytes. 3T3-L1 cells incubated with a PPARgamma agonist during the differentiation process resulted in a 5-fold increase in TGH expression compared to control cells. Evidence for direct regulation of TGH expression by PPARgamma could not be demonstrated as TGH expression was not affected by a 24-h incubation of mature 3T3-L1 adipocytes with the PPARgamma agonist. Feeding mice diets enriched in fatty acids for 3 weeks did not affect hepatic TGH expression, though a 3-week diet enriched in fatty acids and cholesterol increased hepatic TGH expression 2-fold. Two weeks of clofibrate feeding did not significantly affect hepatic TGH expression or microsomal lipolytic activities in wild-type or PPARalpha-null mice, indicating that PPARalpha does not regulate hepatic TGH expression. Therefore, TGH expression does not appear to be directly regulated by PPARs or fatty acids in the liver or adipocytes.
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Affiliation(s)
- Vernon W Dolinsky
- Department of Biochemistry, University of Alberta, 328 Heritage Medical Research Centre, Edmonton, Alberta T6G 2S2, Canada
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28
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Leung D, Hardouin C, Boger DL, Cravatt BF. Discovering potent and selective reversible inhibitors of enzymes in complex proteomes. Nat Biotechnol 2003; 21:687-91. [PMID: 12740587 DOI: 10.1038/nbt826] [Citation(s) in RCA: 291] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2002] [Accepted: 02/24/2003] [Indexed: 11/09/2022]
Abstract
To realize the promise of genomics-based therapeutics, new methods are needed to accelerate the discovery of small molecules that selectively modulate protein activity. Toward this end, advances in combinatorial synthesis have provided unprecedented access to large compound libraries of considerable structural complexity and diversity, shifting the bottleneck in drug discovery to the development of efficient screens for protein targets. Screening for reversible enzyme inhibitors typically requires extensive target-specific work, including protein expression and purification, as well as the development of specific substrate assays. Here we report a proteomic method for the discovery of reversible enzyme inhibitors that avoids these steps. We show that competitive profiling of a library of candidate serine hydrolase inhibitors in complex proteomes with activity-based chemical probes identifies nanomolar reversible inhibitors of several enzymes simultaneously, including the endocannabinoid-degrading enzyme fatty acid amide hydrolase (FAAH), triacylglycerol hydrolase (TGH) and an uncharacterized membrane-associated hydrolase that lacks known substrates. The strategy tests inhibitors against numerous enzymes in parallel, assigning both potency and selectivity factors to each agent. In this way, promiscuous inhibitors were readily rejected in favor of equally potent compounds with 500-fold or greater selectivity for their targets.
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Affiliation(s)
- Donmienne Leung
- The Skaggs Institute for Chemical Biology and the Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, USA
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