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Prochownik EV. Regulation of Normal and Neoplastic Proliferation and Metabolism by the Extended Myc Network. Cells 2022; 11:3974. [PMID: 36552737 PMCID: PMC9777120 DOI: 10.3390/cells11243974] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/30/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
The Myc Network, comprising a small assemblage of bHLH-ZIP transcription factors, regulates many hundreds to thousands of genes involved in proliferation, energy metabolism, translation and other activities. A structurally and functionally related set of factors known as the Mlx Network also supervises some of these same functions via the regulation of a more limited but overlapping transcriptional repertoire. Target gene co-regulation by these two Networks is the result of their sharing of three members that suppress target gene expression as well as by the ability of both Network's members to cross-bind one another's consensus DNA sites. The two Networks also differ in that the Mlx Network's control over transcription is positively regulated by several glycolytic pathway intermediates and other metabolites. These distinctive properties, functions and tissue expression patterns potentially allow for sensitive control of gene regulation in ways that are differentially responsive to environmental and metabolic cues while allowing for them to be both rapid and of limited duration. This review explores how such control might occur. It further discusses how the actual functional dependencies of the Myc and Mlx Networks rely upon cellular context and how they may differ between normal and neoplastic cells. Finally, consideration is given to how future studies may permit a more refined understanding of the functional interrelationships between the two Networks.
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Affiliation(s)
- Edward V. Prochownik
- Division of Hematology/Oncology, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA 15224, USA;
- The Department of Microbiology and Molecular Genetics, The University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
- The UPMC Hillman Comprehensive Cancer Center, Pittsburgh, PA 15232, USA
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, PA 15224, USA
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Nutritional Regulation of Gene Expression: Carbohydrate-, Fat- and Amino Acid-Dependent Modulation of Transcriptional Activity. Int J Mol Sci 2019; 20:ijms20061386. [PMID: 30893897 PMCID: PMC6470599 DOI: 10.3390/ijms20061386] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/12/2019] [Accepted: 03/13/2019] [Indexed: 12/21/2022] Open
Abstract
The ability to detect changes in nutrient levels and generate an adequate response to these changes is essential for the proper functioning of living organisms. Adaptation to the high degree of variability in nutrient intake requires precise control of metabolic pathways. Mammals have developed different mechanisms to detect the abundance of nutrients such as sugars, lipids and amino acids and provide an integrated response. These mechanisms include the control of gene expression (from transcription to translation). This review reports the main molecular mechanisms that connect nutrients’ levels, gene expression and metabolism in health. The manuscript is focused on sugars’ signaling through the carbohydrate-responsive element binding protein (ChREBP), the role of peroxisome proliferator-activated receptors (PPARs) in the response to fat and GCN2/activating transcription factor 4 (ATF4) and mTORC1 pathways that sense amino acid concentrations. Frequently, alterations in these pathways underlie the onset of several metabolic pathologies such as obesity, insulin resistance, type 2 diabetes, cardiovascular diseases or cancer. In this context, the complete understanding of these mechanisms may improve our knowledge of metabolic diseases and may offer new therapeutic approaches based on nutritional interventions and individual genetic makeup.
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Lecompte S, Pasquetti G, Hermant X, Grenier-Boley B, Gonzalez-Gross M, De Henauw S, Molnar D, Stehle P, Béghin L, Moreno LA, Amouyel P, Dallongeville J, Meirhaeghe A. Genetic and molecular insights into the role of PROX1 in glucose metabolism. Diabetes 2013; 62:1738-45. [PMID: 23274905 PMCID: PMC3636631 DOI: 10.2337/db12-0864] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Genome-wide association studies have shown that the rs340874 single nucleotide polymorphism (SNP) in PROX1 is a genetic susceptibility factor for type 2 diabetes. We conducted genetic and molecular studies to better understand the role of PROX1 in type 2 diabetes. We assessed the impact of the whole common genetic variability of PROX1 (80 SNPs) on type 2 diabetes-related biochemical traits in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study (n = 1,155). Three SNPs (rs340838, rs340837, and rs340836) were significantly associated with fasting plasma insulin levels (P ≤ 0.00295). We evaluated the impact of nine PROX1 SNPs (the three insulin-associated SNPs plus six SNPs in strong linkage disequilibrium) on luciferase reporter gene expression. The insulin-lowering alleles of rs340874, rs340873, and rs340835 were associated with lower luciferase activity in MIN6 and HepG2 cells (except for rs340874, which was in HepG2 cells only). Electrophoretic mobility shift assays indicated that specific nuclear protein bindings occur at the three SNPs in HepG2 cells, with allele-binding differences for rs340874. We also showed that the knockdown of Prox1 expression by small interfering RNAs in INS-1E cells resulted in a 1.7-fold reduction in glucose-stimulated insulin secretion. All together, we propose that reduced expression of PROX1 by cis-regulatory variants results in altered β-cell insulin secretion and thereby confers susceptibility to type 2 diabetes.
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Affiliation(s)
- Sophie Lecompte
- INSERM U744, Institut Pasteur de Lille, Université Lille Nord de France, UDSL, Lille, France
| | - Gianni Pasquetti
- INSERM U744, Institut Pasteur de Lille, Université Lille Nord de France, UDSL, Lille, France
| | - Xavier Hermant
- INSERM U744, Institut Pasteur de Lille, Université Lille Nord de France, UDSL, Lille, France
| | - Benjamin Grenier-Boley
- INSERM U744, Institut Pasteur de Lille, Université Lille Nord de France, UDSL, Lille, France
| | - Marcela Gonzalez-Gross
- Department of Health and Human Performance, Faculty of Physical Activity and Sport Sciences, Universidad Politécnica de Madrid, Madrid, Spain
- Department of Nutrition and Food Sciences, University of Bonn, Bonn, Germany
| | - Stephan De Henauw
- Ghent University, Department of Public Health, Ghent University Hospital, Ghent, Belgium
- University College Ghent, Department of Nutrition and Dietetics, Faculty of Health Care Vesalius, Ghent, Belgium
| | - Denes Molnar
- Department of Paediatrics, Medical Faculty, University of Pécs, Pécs, Hungary
| | - Peter Stehle
- Department of Nutrition and Food Sciences, University of Bonn, Bonn, Germany
| | - Laurent Béghin
- INSERM U955, IFR114, Faculty of Medicine, Université Lille 2, Lille, France
- CIC-9301-INSERM-CHRU de Lille, Lille, France
| | - Luis A. Moreno
- GENUD (Growth, Exercise, Nutrition and Development) Research Group, Escuela Universitaria de Ciencias de la Salud, Universidad de Zaragoza, Zaragoza, Spain
| | - Philippe Amouyel
- INSERM U744, Institut Pasteur de Lille, Université Lille Nord de France, UDSL, Lille, France
| | - Jean Dallongeville
- INSERM U744, Institut Pasteur de Lille, Université Lille Nord de France, UDSL, Lille, France
| | - Aline Meirhaeghe
- INSERM U744, Institut Pasteur de Lille, Université Lille Nord de France, UDSL, Lille, France
- Corresponding author: Aline Meirhaeghe,
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Glucose 6P binds and activates HlyIIR to repress Bacillus cereus haemolysin hlyII gene expression. PLoS One 2013; 8:e55085. [PMID: 23405113 PMCID: PMC3566180 DOI: 10.1371/journal.pone.0055085] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 12/17/2012] [Indexed: 11/19/2022] Open
Abstract
Bacillus cereus is a Gram-positive spore-forming bacterium causing food poisoning and serious opportunistic infections. These infections are characterized by bacterial accumulation despite the recruitment of phagocytic cells. We have previously shown that B. cereus Haemolysin II (HlyII) induces macrophage cell death by apoptosis. In this work, we investigated the regulation of the hlyII gene. We show that HlyIIR, the negative regulator of hlyII expression in B. cereus, is especially active during the early bacterial growth phase. We demonstrate that glucose 6P directly binds to HlyIIR and enhances its activity at a post-transcriptional level. Glucose 6P activates HlyIIR, increasing its capacity to bind to its DNA-box located upstream of the hlyII gene, inhibiting its expression. Thus, hlyII expression is modulated by the availability of glucose. As HlyII induces haemocyte and macrophage death, two cell types that play a role in the sequestration of nutrients upon infection, HlyII may induce host cell death to allow the bacteria to gain access to carbon sources that are essential components for bacterial growth.
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The Influence of Ethanol on Pyruvate Kinases Activity in Vivo, in Vitro, in Silico. ACTA ACUST UNITED AC 2013. [DOI: 10.12691/ajmbr-1-1-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Abstract
Current therapies for the treatment of type 1 diabetes include daily administration of exogenous insulin and, less frequently, whole-pancreas or islet transplantation. Insulin injections often result in inaccurate insulin doses, exposing the patient to hypo- and/or hyperglycemic episodes that lead to long-term complications. Islet transplantation is also limited by lack of high-quality islet donors, early graft failure, and chronic post-transplant immunosuppressive treatment. These barriers could be circumvented by designing a safe and efficient strategy to restore insulin production within the patient's body. Porcine islets have been considered as a possible alternative source of transplantable insulin-producing cells to replace human cadaveric islets. More recently, embryonic or induced pluripotent stem cells have also been examined for their ability to differentiate in vitro into pancreatic endocrine cells. Alternatively, it may be feasible to generate new β-cells by ectopic expression of key transcription factors in endogenous non-β-cells. Finally, engineering surrogate β-cells by in vivo delivery of the insulin gene to specific tissues is also being studied as a possible therapy for type 1 diabetes. In the present review, we discuss these different approaches to restore insulin production.
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Affiliation(s)
- Eva Tudurí
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
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Havula E, Hietakangas V. Glucose sensing by ChREBP/MondoA-Mlx transcription factors. Semin Cell Dev Biol 2012; 23:640-7. [PMID: 22406740 DOI: 10.1016/j.semcdb.2012.02.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 02/24/2012] [Indexed: 01/02/2023]
Abstract
The paralogous transcription factors ChREBP and MondoA, together with their common binding partner Mlx, have emerged as key mediators of intracellular glucose sensing. By regulating target genes involved in glycolysis and lipogenesis, they mediate metabolic adaptation to changing glucose levels. As disturbed glucose homeostasis plays a central role in human metabolic diseases and as cancer cells often display altered glucose metabolism, better understanding of cellular glucose sensing will likely uncover new therapeutic opportunities. Here we review the regulation, function and evolutionary conservation of the ChREBP/MondoA-Mlx glucose sensing system and discuss possible directions for future research.
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Affiliation(s)
- Essi Havula
- Institute of Biotechnology, University of Helsinki, Viikinkaari 1, 00014 Helsinki, Finland
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Hines IN, Hartwell HJ, Feng Y, Theve EJ, Hall GA, Hashway S, Connolly J, Fecteau M, Fox JG, Rogers AB. Insulin resistance and metabolic hepatocarcinogenesis with parent-of-origin effects in A×B mice. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:2855-65. [PMID: 21967816 DOI: 10.1016/j.ajpath.2011.08.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 06/24/2011] [Accepted: 08/16/2011] [Indexed: 01/01/2023]
Abstract
Insulin resistance is a defining feature of metabolic syndrome and type 2 diabetes mellitus but also may occur independently of these conditions. Nonalcoholic fatty liver disease (NAFLD), the hepatic manifestation of these disorders, increases the risk of hepatocellular carcinoma (HCC). However, mechanisms linking hyperinsulinemia to NAFLD and HCC require clarification. We describe a novel model of primary insulin resistance and HCC with strong parent-of-origin effects. Male AB6F1 (A/JCr dam × C57BL/6 sire) but not B6AF1 (B6 dam × A/J sire) mice developed spontaneous insulin resistance, NAFLD, and HCC without obesity or diabetes. A survey of mitochondrial, imprinted, and sex-linked traits revealed modest associations with X-linked genes. However, a diet-induced obesity study, including B6.A chromosome substitution-strain (consomic) mice, showed no segregation by sex chromosome. Thus, parent-of-origin effects were specified within the autosomal genome. Next, we interrogated mechanisms of insulin-associated hepatocarcinogenesis. Steatotic hepatocytes exhibited adipogenic transition characterized by vacuolar metaplasia and up-regulation of vimentin, adipsin, fatty acid translocase (CD36), peroxisome proliferator-activated receptor-γ, and related products. This profile was largely recapitulated in insulin-supplemented primary mouse hepatocyte cultures. Importantly, pyruvate kinase M2, a fetal anabolic enzyme implicated in the Warburg effect, was activated by insulin in vivo and in vitro. Thus, our study reveals parent-of-origin effects in heritable insulin resistance, implicating adipogenic transition with acquired anabolic metabolism in the progression from NAFLD to HCC.
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Affiliation(s)
- Ian N Hines
- Department of Nutrition Sciences, East Carolina University, Greenville, North Carolina, USA
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Poupeau A, Postic C. Cross-regulation of hepatic glucose metabolism via ChREBP and nuclear receptors. Biochim Biophys Acta Mol Basis Dis 2011; 1812:995-1006. [PMID: 21453770 DOI: 10.1016/j.bbadis.2011.03.015] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 03/21/2011] [Accepted: 03/22/2011] [Indexed: 01/17/2023]
Abstract
There is a worldwide epidemic of obesity and type 2 diabetes, two major public health concerns associated with alterations in both insulin and glucose signaling pathways. Glucose is not only an energy source but also controls the expression of key genes involved in energetic metabolism, through the glucose-signaling transcription factor, Carbohydrate Responsive Element Binding Protein (ChREBP). ChREBP has emerged as a central regulator of de novo fatty acid synthesis (lipogenesis) in response to glucose under both physiological and physiopathological conditions. Glucose activates ChREBP by regulating its entry from the cytosol to the nucleus, thereby promoting its binding to carbohydrate responsive element (ChoRE) in the promoter regions of glycolytic (L-PK) and lipogenic genes (ACC and FAS). We have previously reported that the inhibition of ChREBP in liver of obese ob/ob mice improves the metabolic alterations linked to obesity, fatty liver and insulin-resistance. Therefore, regulating ChREBP activity could be an attractive target for lipid-lowering therapies in obesity and diabetes. However, before this is possible, a better understanding of the mechanism(s) regulating its activity is needed. In this review, we summarize recent findings on the role and regulation of ChREBP and particularly emphasize on the cross-regulations that may exist between key nuclear receptors (LXR, TR, HNF4α) and ChREBP for the control of hepatic glucose metabolism. These novel molecular cross-talks may open the way to new pharmacological opportunities. This article is part of a Special Issue entitled: Translating nuclear receptors from health to disease.
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Davies MN, O'Callaghan BL, Towle HC. Activation and repression of glucose-stimulated ChREBP requires the concerted action of multiple domains within the MondoA conserved region. Am J Physiol Endocrinol Metab 2010; 299:E665-74. [PMID: 20682844 PMCID: PMC2957870 DOI: 10.1152/ajpendo.00349.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carbohydrate response element-binding protein (ChREBP) is a glucose-dependent transcription factor that stimulates the expression of glycolytic and lipogenic genes in mammals. Glucose regulation of ChREBP has been mapped to its conserved NH(2)-terminal region of 300 amino acids, designated the MondoA conserved region (MCR). Within the MCR, five domains (MCR1-5) have a particularly high level of conservation and are likely to be important for glucose regulation. We carried out a large-scale deletion and substitution mutational analysis of the MCR domain of ChREBP. This analysis revealed that MCRs 1-4 function in a concerted fashion to repress ChREBP activity in basal (nonstimulatory) conditions. Deletion of the entire MCR1-4 segment or the combination of four specific point mutations located across this region leads to a highly active, glucose-independent form of ChREBP. However, deletion of any individual MCR domain and the majority of point mutations throughout MCR1-4 rendered ChREBP inactive. These observations suggest that the MCR1-4 region interacts with an additional coregulatory factor required for activation. This possibility is supported by the observation that the MCR1-4 region can compete for activity with wild-type ChREBP in stimulatory conditions. In contrast, mutations in the MCR5 domain result in increased activity, suggesting that this domain may be the target of intramolecular repression in basal conditions. Thus, the MCR domains act in a complex and coordinated manner to regulate ChREBP activity in response to glucose.
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Affiliation(s)
- Michael N Davies
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Zhang P, Metukuri MR, Bindom SM, Prochownik EV, O'Doherty RM, Scott DK. c-Myc is required for the CHREBP-dependent activation of glucose-responsive genes. Mol Endocrinol 2010; 24:1274-86. [PMID: 20382893 DOI: 10.1210/me.2009-0437] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Glucose regulates programs of gene expression that orchestrate changes in cellular phenotype in several metabolically active tissues. Carbohydrate response element-binding protein (ChREBP) and its binding partner, Mlx, mediate glucose-regulated gene expression by binding to carbohydrate response elements on target genes, such as the prototypical glucose-responsive gene, liver-type pyruvate kinase (Pklr). c-Myc is also required for the glucose response of the Pklr gene, although the relationship between c-Myc and ChREBP has not been defined. Here we describe the molecular events of the glucose-mediated activation of Pklr and determine the effects of decreasing the activity or abundance of c-Myc on this process. Time-course chromatin immunoprecipitation revealed a set of transcription factors [hepatocyte nuclear factor (HNF)1alpha, HNF4alpha, and RNA polymerase II (Pol II)] constitutively resident on the Pklr promoter, with a relative enrichment of acetylated histones 3 and 4 in the same region of the gene. Glucose did not affect HNF1alpha binding or the acetylation of histones H3 or H4. By contrast, glucose promoted the recruitment of ChREBP and c-Myc and increased the occupancy of HNF4alpha and RNA Pol II, which were coincident with the glucose-mediated increase in transcription as determined by a nuclear run-on assay. Depletion of c-Myc activity using a small molecule inhibitor (10058-F4/1RH) abolished the glucose-mediated recruitment of HNF4alpha, ChREBP, and RNA Pol II, without affecting basal gene expression, histone acetylation, and HNF1alpha or basal HNF4alpha occupancy. The activation and recruitment of ChREBP to several glucose-responsive genes were blocked by 1RH, indicating a general necessity for c-Myc in this process.
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Affiliation(s)
- Pili Zhang
- Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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Cha-Molstad H, Saxena G, Chen J, Shalev A. Glucose-stimulated expression of Txnip is mediated by carbohydrate response element-binding protein, p300, and histone H4 acetylation in pancreatic beta cells. J Biol Chem 2009; 284:16898-16905. [PMID: 19411249 DOI: 10.1074/jbc.m109.010504] [Citation(s) in RCA: 174] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Recently, we identified Txnip (thioredoxin-interacting protein) as a mediator of glucotoxic beta cell death and discovered that lack of Txnip protects against streptozotocin- and obesity-induced diabetes by preventing beta cell apoptosis and preserving endogenous beta cell mass. Txnip has therefore become an attractive target for diabetes therapy, but although we have found that txnip transcription is highly induced by glucose through a unique carbohydrate response element, the factors controlling this effect have remained unknown. Using transient transfection experiments, we now show that overexpression of the carbohydrate response element-binding protein (ChREBP) transactivates the txnip promoter, whereas ChREBP knockdown by small interfering RNA completely blunts glucose-induced txnip transcription. Moreover, chromatin immunoprecipitation demonstrated that glucose leads to a dose- and time-dependent recruitment of ChREBP to the txnip promoter in vivo in INS-1 beta cells as well as human islets. Furthermore, we found that the co-activator and histone acetyltransferase p300 co-immunoprecipitates with ChREBP and also binds to the txnip promoter in response to glucose. Interestingly, this is associated with specific acetylation of histone H4 and recruitment of RNA polymerase II as measured by chromatin immunoprecipitation. Thus, with this study we have identified ChREBP as the transcription factor that mediates glucose-induced txnip expression in human islets and INS-1 beta cells and have characterized the chromatin modification associated with glucose-induced txnip transcription. In addition, the results reveal for the first time that ChREBP interacts with p300. This may explain how ChREBP induces H4 acetylation and sheds new light on glucose-mediated regulation of chromatin structure and transcription.
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Affiliation(s)
- Hyunjoo Cha-Molstad
- From the Department of Medicine, University of Wisconsin, Madison, Wisconsin 53792; William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin 53705
| | - Geetu Saxena
- From the Department of Medicine, University of Wisconsin, Madison, Wisconsin 53792; William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin 53705
| | - Junqin Chen
- From the Department of Medicine, University of Wisconsin, Madison, Wisconsin 53792; William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin 53705
| | - Anath Shalev
- From the Department of Medicine, University of Wisconsin, Madison, Wisconsin 53792; William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin 53705.
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