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Kongthitilerd P, Barras E, Rong W, Thibodeaux A, Rigdon M, Yao S, Adisakwattana S, Suantawee T, Cheng H. Cyanidin inhibits adipogenesis in 3T3-L1 preadipocytes by activating the PLC-IP 3 pathway. Biomed Pharmacother 2023; 162:114677. [PMID: 37044024 DOI: 10.1016/j.biopha.2023.114677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 03/31/2023] [Accepted: 04/06/2023] [Indexed: 04/14/2023] Open
Abstract
Cyanidin is the most abundant anthocyanin found in red-purple plants and possesses anti-obesity properties. However, its mechanism of action in adipocytes remains unknown. The objective of this study was to elucidate how cyanidin inhibits adipocyte formation in 3T3-L1 preadipocytes. Cells were cultured in adipogenic differentiation medium supplemented with cyanidin and examined for adipogenesis, cell viability, and adipocyte gene expression using Oil Red O staining, MTT assay, and RT-qPCR. Real-time Ca2+ imaging analysis was performed in living cells to elucidate cyanidin's mechanism of action. The results demonstrated that cyanidin (1-50 μM) supplementation to the adipogenic medium inhibited adipogenesis by downregulating adipogenic marker gene expression (PPARγ, C/EBPα, adiponectin, and aP2) without affecting cell viability after 4 days of treatment. Stimulation of cells with cyanidin (30-100 μM) increased intracellular Ca2+ in a concentration dependent manner with peak calcium increases at 50 μM. Pretreatment of cells with the phospholipase C (PLC) inhibitor U73122, inositol triphosphate (IP3) receptor blocker 2-APB, and depletion of endoplasmic reticulum Ca2+ stores by thapsigargin abolished the Ca2+ increases by cyanidin. These findings suggested that cyanidin inhibits adipocyte formation by activating the PLC-IP3 pathway and intracellular Ca2+ signaling. Our study is the first report describing the mechanism underlying the anti-obesity effect of cyanidin.
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Affiliation(s)
- Phutthida Kongthitilerd
- Department of Nutrition and Dietetics, Faculty of Allied Health Sciences, Burapha University, Chonburi 20131, Thailand; Interdisciplinary Program of Biomedical Sciences, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand; Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA
| | - Elise Barras
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Weiqiong Rong
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Ansleigh Thibodeaux
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Madison Rigdon
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Shaomian Yao
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Sirichai Adisakwattana
- Phytochemical and Functional Food Research Unit for Clinical Nutrition, Department of Nutrition and Dietetics, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand
| | - Tanyawan Suantawee
- Phytochemical and Functional Food Research Unit for Clinical Nutrition, Department of Nutrition and Dietetics, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand.
| | - Henrique Cheng
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA.
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2
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Andréjak C, Barras E. [Interferon gamma release assay tests and nontuberculous mycobacteria]. Rev Mal Respir 2018; 35:900-901. [PMID: 30220488 DOI: 10.1016/j.rmr.2018.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 03/21/2018] [Indexed: 10/28/2022]
Affiliation(s)
- C Andréjak
- Service de pneumologie et réanimation, CHU Amiens Picardie, université Picardie Jules-Verne, EA 4294, 80054 Amiens cedex 1, France.
| | - E Barras
- Service de pneumologie et réanimation, CHU Amiens Picardie, université Picardie Jules-Verne, EA 4294, 80054 Amiens cedex 1, France
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3
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Bergot E, Abiteboul D, Andréjak C, Antoun F, Barras E, Blanc FX, Bourgarit A, Charlois-Ou C, Delacourt C, Dirou S, Gerin M, Guerin S, Haustraete É, Henry B, Lucet JC, Maitre T, Morin J, Le Palud P, Pommelet V, Rivoisy C, Robert J, Veziris N, Herrmann JL. [Practice recommendations for the use and interpretation of interferon gamma release assays in the diagnosis of latent and active tuberculosis]. Rev Mal Respir 2018; 35:852-858. [PMID: 30224215 DOI: 10.1016/j.rmr.2018.08.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 03/21/2018] [Indexed: 11/29/2022]
Affiliation(s)
- E Bergot
- Service de pneumologie, CHRU Côte de Nacre, 14033 Caen, France
| | - D Abiteboul
- Groupe d'étude sur le risque d'exposition de soignants aux agents infectieux (GERES), UFR de Médecine-site Bichat, 75018 Paris, France
| | - C Andréjak
- Service de pneumologie et réanimation, CHU Amiens Picardie, université Picardie Jules Verne, EA 4294, 80054 Amiens cedex 1, France
| | - F Antoun
- Département de Paris, centre de lutte anti tuberculeuse, direction de l'action sociale de l'enfance et de la santé, 75013 Paris, France
| | - E Barras
- Service de pneumologie et réanimation, CHU Amiens Picardie, université Picardie Jules Verne, EA 4294, 80054 Amiens cedex 1, France
| | - F-X Blanc
- Service de pneumologie, l'institut du thorax, CHU de Nantes, université de Nantes, 44093 Nantes cedex 1, France
| | - A Bourgarit
- Service de médecine interne, hôpital Jean Verdier, AP-HP, HUPSSD, 93140 Bondy, France; Inserm UMR 1149 CRI, université Paris 13, SmBH, 93140 Bondy, France
| | - C Charlois-Ou
- Département de Paris, centre de lutte anti tuberculeuse, direction de l'action sociale de l'enfance et de la santé, 75013 Paris, France
| | - C Delacourt
- Hôpital Necker-Enfants Malades, AP-HP, 75015 Paris, France
| | - S Dirou
- Service de pneumologie, l'institut du thorax, CHU de Nantes, université de Nantes, 44093 Nantes cedex 1, France
| | - M Gerin
- Inserm UMR 1149 CRI, université Paris 13, SmBH, 93140 Bondy, France
| | - S Guerin
- Hôpital Necker-Enfants Malades, AP-HP, 75015 Paris, France
| | - É Haustraete
- Service de Pneumologie, centre hospitalier Robert Bisson, 14107 Lisieux, France
| | - B Henry
- Service des maladies infectieuses et tropicales, centre d'infectiologie Necker Pasteur, hôpital Necker Enfants Malades, AP-HP, 75015 Paris, France; Institut Imagine, université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - J-C Lucet
- Unité d'hygiène de et de lutte contre l'infection nosocomiale (UHLIN), GH Bichat-Claude Bernard, AP-HP , 75877 Paris, France
| | - T Maitre
- Inserm, U1135, centre d'immunologie et des maladies infectieuses, Sorbonne universités, Sorbonne université, 75013 Paris, France
| | - J Morin
- Service de pneumologie, l'institut du thorax, CHU de Nantes, université de Nantes, 44093 Nantes cedex 1, France
| | - P Le Palud
- Service de pneumologie, CHRU Côte de Nacre, 14033 Caen, France
| | - V Pommelet
- Service de pédiatrie générale, hôpital Robert-Debré, AP-HP, 75019 Paris, France
| | - C Rivoisy
- Service de médecine interne, hôpital Jean Verdier, AP-HP, HUPSSD, 93140 Bondy, France
| | - J Robert
- Inserm, U1135, centre d'immunologie et des maladies infectieuses, Sorbonne universités, Sorbonne université, 75013 Paris, France; Laboratoire de bactériologie-hygiène, hôpital Pitié-Salpêtrière, centre national de référence des mycobactéries et de la résistance des mycobactéries aux antituberculeux, AP-HP, 75013 Paris, France
| | - N Veziris
- Inserm, U1135, centre d'immunologie et des maladies infectieuses, Sorbonne universités, Sorbonne université, 75013 Paris, France; Département de bactériologie, hôpitaux universitaires de l'Est Parisien, centre national de référence des mycobactéries, AP-HP, 75012, Paris, France
| | - J-L Herrmann
- Laboratoire de bactériologie-hygiène, GHU hôpitaux Ile de France-Ouest, hôpital Raymond Poincaré, AP-HP, 92380 Garches, France; UMR1173, Inserm, université de Versailles Saint Quentin, UFR des sciences de la santé, 78180 Montigny le Bretonneux, France.
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Barras E, Andrejak C, Jounieaux V. Coinfections à Mycobactéries non tuberculeuses et Aspergillus fumigatus. Rev Mal Respir 2015. [DOI: 10.1016/j.rmr.2014.11.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bonnafe E, Touka M, AitLounis A, Baas D, Barras E, Ucla C, Moreau A, Flamant F, Dubruille R, Couble P, Collignon J, Durand B, Reith W. The transcription factor RFX3 directs nodal cilium development and left-right asymmetry specification. Mol Cell Biol 2004; 24:4417-27. [PMID: 15121860 PMCID: PMC400456 DOI: 10.1128/mcb.24.10.4417-4427.2004] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
There are five members of the RFX family of transcription factors in mammals. While RFX5 plays a well-defined role in the immune system, the functions of RFX1 to RFX4 remain largely unknown. We have generated mice with a deletion of the Rfx3 gene. RFX3-deficient mice exhibit frequent left-right (LR) asymmetry defects leading to a high rate of embryonic lethality and situs inversus in surviving adults. In vertebrates, specification of the LR body axis is controlled by monocilia in the embryonic node, and defects in nodal cilia consequently result in abnormal LR patterning. Consistent with this, Rfx3 is expressed in ciliated cells of the node and RFX3-deficient mice exhibit a pronounced defect in nodal cilia. In contrast to the case for wild-type embryos, for which we document for the first time a twofold increase in the length of nodal cilia during development, the cilia are present but remain markedly stunted in mutant embryos. Finally, we show that RFX3 regulates the expression of D2lic, the mouse orthologue of a Caenorhabditis elegans gene that is implicated in intraflagellar transport, a process required for the assembly and maintenance of cilia. In conclusion, RFX3 is essential for the differentiation of nodal monocilia and hence for LR body axis determination.
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Affiliation(s)
- E Bonnafe
- Centre de Génétique Moléculaire et Cellulaire, CNRS UMR 5534, Université Claude Bernard Lyon-1, F-69622 Villeurbanne, France
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Peretti M, Villard J, Barras E, Zufferey M, Reith W. Expression of the three human major histocompatibility complex class II isotypes exhibits a differential dependence on the transcription factor RFXAP. Mol Cell Biol 2001; 21:5699-709. [PMID: 11486010 PMCID: PMC87290 DOI: 10.1128/mcb.21.17.5699-5709.2001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2001] [Accepted: 06/11/2001] [Indexed: 11/20/2022] Open
Abstract
Major histocompatibility complex class II (MHCII) molecules play a pivotal role in the immune system because they direct the development and activation of CD4(+) T cells. There are three human MHCII isotypes, HLA-DR, HLA-DQ, and HLA-DP. Key transcription factors controlling MHCII genes have been identified by virtue of the fact that they are mutated in a hereditary immunodeficiency resulting from a lack of MHCII expression. RFXAP-one of the factors affected in this disease-is a subunit of RFX, a DNA-binding complex that recognizes the X box present in all MHCII promoters. To facilitate identification of conserved regions in RFXAP, we isolated the mouse gene. We then delimited conserved domains required to restore endogenous MHCII expression in cell lines lacking a functional RFXAP gene. Surprisingly, we found that 80% of RFXAP is dispensable for the reactivation of DR expression. Only a short C-terminal segment of the protein is essential for this isotype. In contrast, optimal expression of DQ and DP requires a larger C-terminal segment. These results define an RFXAP domain with an MHCII isotype-specific function. Expression of the three MHCII isotypes exhibits a differential requirement for this domain. We show that this is due to a differential dependence on this domain for promoter occupation and recruitment of the coactivator CIITA in vivo.
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Affiliation(s)
- M Peretti
- Department of Genetics and Microbiology, University of Geneva Medical School, CMU, 1 rue Michel-Servet, 1211 Geneva, Switzerland
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Villard J, Reith W, Barras E, Gos A, Morris MA, Antonarakis SE, Van den Elsen PJ, Mach B. Analysis of mutations and chromosomal localisation of the gene encoding RFX5, a novel transcription factor affected in major histocompatibility complex class II deficiency. Hum Mutat 2000; 10:430-5. [PMID: 9401005 DOI: 10.1002/(sici)1098-1004(1997)10:6<430::aid-humu3>3.0.co;2-h] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
MHC class II deficiency is a severe primary immunodeficiency characterised by the absence of major histocompatibility complex class II (MHC-II) gene expression. It is genetically heterogeneous and can result from defects in at least four different trans-acting regulatory genes required for transcription of MHC-II genes. One of these genes has recently been shown to encode a novel DNA binding protein called RFX5, which is one subunit of a heteromeric protein complex (RFX) that binds to the promoters of MHC-II genes. We have characterised the mutations in all four patients known to harbour a defect in the RFX5 gene and have mapped this new human disease gene to chromosome 1 band q21, a region frequently exhibiting chromosomal aberrations in a variety of preneoplastic and neoplastic diseases.
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Affiliation(s)
- J Villard
- Department of Genetics and Microbiology, University of Geneva Medical School, Switzerland
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8
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Villard J, Peretti M, Masternak K, Barras E, Caretti G, Mantovani R, Reith W. A functionally essential domain of RFX5 mediates activation of major histocompatibility complex class II promoters by promoting cooperative binding between RFX and NF-Y. Mol Cell Biol 2000; 20:3364-76. [PMID: 10779326 PMCID: PMC85629 DOI: 10.1128/mcb.20.10.3364-3376.2000] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/1999] [Accepted: 02/18/2000] [Indexed: 11/20/2022] Open
Abstract
Major histocompatibility complex class II (MHC-II) molecules occupy a pivotal position in the adaptive immune system, and correct regulation of their expression is therefore of critical importance for the control of the immune response. Several regulatory factors essential for the transcription of MHC-II genes have been identified by elucidation of the molecular defects responsible for MHC-II deficiency, a hereditary immunodeficiency disease characterized by regulatory defects abrogating MHC-II expression. Three of these factors, RFX5, RFXAP, and RFXANK, combine to form the RFX complex, a regulatory protein that binds to the X box DNA sequence present in all MHC-II promoters. In this study we have undertaken a dissection of the structure and function of RFX5, the largest subunit of the RFX complex. The results define two distinct domains serving two different essential functions. A highly conserved N-terminal region of RFX5 is required for its association with RFXANK and RFXAP, for assembly of the RFX complex in vivo and in vitro, and for binding of this complex to its X box target site in the MHC-II promoter. This N-terminal region is, however, not sufficient for activation of MHC-II expression. This requires an additional domain within the C-terminal region of RFX5. This C-terminal domain mediates cooperative binding between the RFX complex and NF-Y, a transcription factor binding to the Y box sequence of MHC-II promoters. This provides direct evidence that RFX5-mediated cooperative binding between RFX and NF-Y plays an essential role in the transcriptional activation of MHC-II genes.
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Affiliation(s)
- J Villard
- Department of Genetics and Microbiology, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland.
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9
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Masternak K, Barras E, Zufferey M, Conrad B, Corthals G, Aebersold R, Sanchez JC, Hochstrasser DF, Mach B, Reith W. A gene encoding a novel RFX-associated transactivator is mutated in the majority of MHC class II deficiency patients. Nat Genet 1998; 20:273-7. [PMID: 9806546 DOI: 10.1038/3081] [Citation(s) in RCA: 220] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Major histocompatibility class II (MHC-II) molecules are transmembrane proteins that have a central role in development and control of the immune system. They are encoded by a multigene family and their expression is tightly regulated. MHC-II deficiency (OMIM 209920) is an autosomal recessive immunodeficiency syndrome resulting from defects in trans-acting factors essential for transcription of MHC-II genes. There are four genetic complementation groups (A, B, C and D), reflecting the existence of four MHC-II regulators. The factors defective in groups A (CIITA), C (RFX5) and D (RFXAP) have been identified. CIITA is a non-DNA-binding co-activator that controls the cell-type specificity and inducibility of MHC-II expression. RFX5 and RFXAP are two subunits of RFX, a multi-protein complex that binds the X box motif of MHC-II promoters. Mutations in the genes encoding RFX5 (RFX5) or RFXAP (RFXAP) abolish binding of RFX (refs 7,8,12). Similar to groups C and D, group B is characterized by a defect in RFX binding, and although it accounts for the majority of patients, the factor defective in group B has remained unknown. We report here the isolation of RFX by a novel single-step DNA-affinity purification approach and the identification of RFXANK, the gene encoding a third subunit of RFX. RFXANK restores MHC-II expression in cell lines from patients in group B and is mutated in these patients. RFXANK contains a protein-protein interaction region consisting of three ankyrin repeats. Its interaction with RFX5 and RFXAP is essential for binding of the RFX complex to MHC-II promoters.
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Affiliation(s)
- K Masternak
- Louis Jeantet Laboratory of Molecular Genetics, Department of Genetics and Microbiology, University of Geneva Medical School, Switzerland
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Clausen BE, Waldburger JM, Schwenk F, Barras E, Mach B, Rajewsky K, Förster I, Reith W. Residual MHC class II expression on mature dendritic cells and activated B cells in RFX5-deficient mice. Immunity 1998; 8:143-55. [PMID: 9491996 DOI: 10.1016/s1074-7613(00)80467-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Patients with major histocompatibility complex class II (MHC-II) deficiency are known to carry mutations in either the RFX complex or the trans-activator CIITA. While the pivotal role of CIITA for MHC-II gene transcription is supported by the essential absence of MHC-II molecules in CIITA-deficient mice, we demonstrate here that RFX5-/- mice retain expression of MHC-II in thymic medulla, mature dendritic cells, and activated B cells. Nevertheless, RFX5-/- mice develop a severe immunodeficiency due to the lack of MHC-II in thymic cortex, failure of positive selection of CD4+ T cells, and absence of MHC-II on resting B cells and resident or IFNgamma-activated macrophages. This differential requirement for CIITA and RFX5 in subsets of antigen-presenting cells may be specific for the mouse; it may, however, also exist in humans without having been noticed so far.
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Affiliation(s)
- B E Clausen
- Institute for Genetics, University of Cologne, Germany
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11
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Barras E. [Bottle fed children with caries: dental care under general anesthesia]. Rev Med Suisse Romande 1998; 118:7-12. [PMID: 9528316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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12
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Durand B, Sperisen P, Emery P, Barras E, Zufferey M, Mach B, Reith W. RFXAP, a novel subunit of the RFX DNA binding complex is mutated in MHC class II deficiency. EMBO J 1997; 16:1045-55. [PMID: 9118943 PMCID: PMC1169704 DOI: 10.1093/emboj/16.5.1045] [Citation(s) in RCA: 183] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Major Histocompatibility Complex class II (MHC-II) deficiency is a disease of gene regulation that provides a unique opportunity for the genetic dissection of the molecular mechanisms controlling transcription of MHC-II genes. Cell lines from MHC-II deficiency patients have been assigned to three complementation groups (A, B and C) believed to reflect the existence of distinct essential MHC-II regulatory genes. Groups B and C, as well as an in vitro generated regulatory mutant representing a fourth group (D), are characterized by a specific defect in the binding activity of RFX, a multimeric DNA binding complex that is essential for activation of MHC-II promoters. RFX5, a subunit of RFX, was recently shown to be mutated in group C. We have now isolated a novel gene, RFXAP (RFX Associated Protein), that encodes a second subunit of the RFX complex. RFXAP is mutated in the 6.1.6 cell line (group D), as well as in an MHC-II deficiency patient (DA). This establishes that group D is indeed a fourth MHC-II deficiency complementation group. Complementation of the 6.1.6 and DA cell lines by transfection with RFXAP fully restores expression of all endogenous MHC-II genes in vivo, demonstrating that RFXAP is a novel essential MHC-II regulatory gene.
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Affiliation(s)
- B Durand
- Department of Genetics and Microbiology, University of Geneva Medical School, Switzerland
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13
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Steimle V, Durand B, Barras E, Zufferey M, Hadam MR, Mach B, Reith W. A novel DNA-binding regulatory factor is mutated in primary MHC class II deficiency (bare lymphocyte syndrome). Genes Dev 1995; 9:1021-32. [PMID: 7744245 DOI: 10.1101/gad.9.9.1021] [Citation(s) in RCA: 274] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Regulation of MHC class II gene expression is an essential aspect of the control of the immune response. Primary MHC class II deficiency is a genetically heterogeneous disease of gene regulation that offers the unique opportunity of a genetic approach for the identification of the functionally relevant regulatory genes and factors. Most patients exhibit a characteristic defect in the binding of a nuclear complex, RFX, to the X box motif of MHC class II promoters. Genetic complementation of a B-lymphocyte cell line from such a patient with a cDNA expression library has allowed us to isolate RFX5, the regulatory gene responsible for the MHC class II deficiency. This gene encodes a novel DNA-binding protein that is indeed a subunit of the RFX complex. Mutations in the RFX5 gene have been characterized in two patients. Transfection of the patient's cells with the RFX5 cDNA repairs the binding defect and fully restores expression of all the endogenous MHC class II genes in vivo.
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Affiliation(s)
- V Steimle
- Jeantet Laboratory of Molecular Genetics, Department of Genetics and Microbiology, University of Geneva Medical School, Switzerland
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14
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Reith W, Ucla C, Barras E, Gaud A, Durand B, Herrero-Sanchez C, Kobr M, Mach B. RFX1, a transactivator of hepatitis B virus enhancer I, belongs to a novel family of homodimeric and heterodimeric DNA-binding proteins. Mol Cell Biol 1994; 14:1230-44. [PMID: 8289803 PMCID: PMC358479 DOI: 10.1128/mcb.14.2.1230-1244.1994] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
RFX1 is a transactivator of human hepatitis B virus enhancer I. We show here that RFX1 belongs to a previously unidentified family of DNA-binding proteins of which we have cloned three members, RFX1, RFX2, and RFX3, from humans and mice. Members of the RFX family constitute the nuclear complexes that have been referred to previously as enhancer factor C, EP, methylation-dependent DNA-binding protein, or rpL30 alpha. RFX proteins share five strongly conserved regions which include the two domains required for DNA binding and dimerization. They have very similar DNA-binding specificities and heterodimerize both in vitro and in vivo. mRNA levels for all three genes, particularly RFX2, are elevated in testis. In other cell lines and tissues, RFX mRNA levels are variable, particularly for RFX2 and RFX3. RFX proteins share several novel features, including new DNA-binding and dimerization motifs and a peculiar dependence on methylated CpG dinucleotides at certain sites.
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Affiliation(s)
- W Reith
- Jeantet Laboratory of Molecular Genetics, Department of Genetics and Microbiology, University of Geneva Medical School, Centre Médical Universitaire, Switzerland
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15
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Reith W, Siegrist CA, Durand B, Barras E, Mach B. Function of major histocompatibility complex class II promoters requires cooperative binding between factors RFX and NF-Y. Proc Natl Acad Sci U S A 1994; 91:554-8. [PMID: 8290561 PMCID: PMC42987 DOI: 10.1073/pnas.91.2.554] [Citation(s) in RCA: 147] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Transcription of major histocompatibility complex (MHC) class II genes is controlled largely by the conserved promoter elements called the X and Y boxes. We show here that RFX, the X box-binding protein deficient in certain MHC class II-deficient immunodeficiency patients (CID), and the Y box-binding protein NF-Y bind cooperatively. Functional relevance of this protein-protein interaction is suggested by the fact that promoter activity correlates with cooperative binding of RFX and NF-Y rather than with binding of RFX or NF-Y alone. Stability of the RFX/NF-Y complex is affected by alterations in X-Y box spacing. These results are consistent with the fact that MHC class II promoter function is dependent on correct stereospecific alignment of the X and Y boxes. Cooperative binding involving RFX, NF-Y, and perhaps other MHC class II promoter-binding proteins may explain why the highly specific defect in binding of RFX observed in CID cells is associated in vivo with a bare promoter in which all of the cis-acting elements, including the X and Y boxes, are unoccupied.
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Affiliation(s)
- W Reith
- Jeantet Laboratory of Molecular Genetics, Department of Genetics and Microbiology, University of Geneva Medical School, Switzerland
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Reith W, Herrero-Sanchez C, Kobr M, Silacci P, Berte C, Barras E, Fey S, Mach B. MHC class II regulatory factor RFX has a novel DNA-binding domain and a functionally independent dimerization domain. Genes Dev 1990; 4:1528-40. [PMID: 2253877 DOI: 10.1101/gad.4.9.1528] [Citation(s) in RCA: 136] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The regulation of MHC class II gene expression controls T-cell activation and, hence, the immune response. Among the nuclear factors observed to bind to conserved DNA sequences in human leukocyte antigen (HLA) class II gene promoters, RFX is of special interest: Its binding is defective in congenital HLA class II deficiency, a disease of class II gene regulation. The cloning of an RFX cDNA has allowed us to show by transfection of a plasmid directing the synthesis of antisense RFX RNA that RFX is a class II gene regulatory factor. RFX is a novel 979-amino-acid DNA-binding protein that contains three structurally and functionally separate domains. The 91-amino-acid DNA-binding domain is distinct from other known DNA-binding motifs but may be distantly related to the helix-loop-helix motif. The most striking property of RFX is that it can bind stably to the class II X box as either a monomer or a homodimer and that the domain responsible for dimerization is distant from and functionally independent of the DNA-binding domain. This distinguishes RFX from other known dimeric DNA-binding proteins. It also implies that an RFX homodimer has two potential DNA-binding sites. We therefore speculate that RFX could form a DNA loop by cross-linking the two X-box sequences found far apart upstream of MHC class II genes.
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Affiliation(s)
- W Reith
- Department of Microbiology, University of Geneva Medical School, Switzerland
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Reith W, Barras E, Satola S, Kobr M, Reinhart D, Sanchez CH, Mach B. Cloning of the major histocompatibility complex class II promoter binding protein affected in a hereditary defect in class II gene regulation. Proc Natl Acad Sci U S A 1989; 86:4200-4. [PMID: 2498880 PMCID: PMC287418 DOI: 10.1073/pnas.86.11.4200] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The regulation of major histocompatibility complex class II gene expression is directly involved in the control of normal and abnormal immune responses. In humans, HLA-DR, -DQ, and -DP class II heterodimers are encoded by a family of alpha- and beta-chain genes clustered in the major histocompatibility complex. Their expression is developmentally controlled and normally restricted to certain cell types. This control is mediated by cis-acting sequences in class II promoters and by trans-acting regulatory factors. Several nuclear proteins bind to class II promoter sequences. In a form of hereditary immunodeficiency characterized by a defect in a trans-acting regulatory factor controlling class II gene transcription, we have observed that one of these nuclear factors (RF-X) does not bind to its target sequence (the class II X box). A cDNA encoding RF-X was isolated by screening a phage expression library with an X-box binding-site probe. The recombinant protein has the binding specificity of RF-X, including a characteristic gradient of affinity for the X boxes of HLA-DR, -DP, and -DQ promoters. RF-X mRNA is present in the regulatory mutants, indicating a defect in the synthesis of a functional form of the RF-X protein.
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Affiliation(s)
- W Reith
- Department of Microbiology, University of Geneva Medical School, Switzerland
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Gönczy P, Reith W, Barras E, Lisowska-Grospierre B, Griscelli C, Hadam MR, Mach B. Inherited immunodeficiency with a defect in a major histocompatibility complex class II promoter-binding protein differs in the chromatin structure of the HLA-DRA gene. Mol Cell Biol 1989; 9:296-302. [PMID: 2467188 PMCID: PMC362172 DOI: 10.1128/mcb.9.1.296-302.1989] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A defect in a trans-regulatory factor which controls major histocompatibility complex class II gene expression is responsible for an inherited form of immunodeficiency with a lack of expression of human leukocyte antigen (HLA) class II antigens. We have recently described and cloned an HLA class II promoter DNA-binding protein, RF-X, present in normal B cells and absent in these class II-deficient regulatory mutants. Here we report that these in vitro results correlate with a specific change in the chromatin structure of the class II promoter: two prominent DNase I-hypersensitive sites were identified in the promoter of the HLA-DRA gene in normal B lymphocytes and found to be absent in the class II-deficient mutant cells. The same two prominent DNase I-hypersensitive sites were observed in normal fibroblastic cells induced by gamma interferon to express class II genes. Interestingly, they were also observed in the uninduced class II-negative fibroblastic cells, which have also been shown to have a normal RF-X binding pattern. We conclude that the two DNase I-hypersensitive sites in the HLA-DRA promoter reflect features in chromatin structure which correlate with the binding of the trans-acting factor RF-X and which are necessary but not sufficient for the expression of class II genes.
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Affiliation(s)
- P Gönczy
- Department of Microbiology, University of Geneva Medical School, Switzerland
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Weir GC, Leahy JL, Barras E, Braunstein LP. Characteristics of insulin and glucagon release from the perfused pancreas, intact isolated islets, and dispersed islet cells. Horm Res 1986; 24:62-72. [PMID: 3530935 DOI: 10.1159/000180540] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
There are a variety of different tissue preparations which have been used to study secretion from the endocrine pancreas and there are considerable differences in the results obtained from these. The purpose of this study was to compare several preparations in one laboratory using the same rats, buffers, and radioimmunoassays. The preparations included the isolated perfused rat pancreas, fresh isolated intact islets and dispersed cells, and cultured islets and cells. Insulin release from the perfused rat pancreas at 2.8 mM glucose was so low that it could not be measured, such that over a 90-min time period the amount of insulin released was less than 0.004% of pancreatic insulin content. In contrast, islets in static incubation appear to release 2.0% of their stored content and dispersed cells appear to release 2.6% of their content. Samples were taken at early time points during incubations of fresh islets and dispersed cells, and it was found that almost all of the insulin found at the end of a 90-min incubation period was present during the first 5 min. It is therefore suspected that the true secretory rate of insulin at a low glucose concentration is far lower than had been generally appreciated. Glucagon release patterns showed similarities in that with isolated islets and dispersed cells a disproportionate amount of glucagon release was found during a 0- to 30-min incubation period when compared with the 30- to 90-min period. In summary, artifacts have been identified in some of the in vitro systems used for the study of endocrine pancreatic secretion and these deserve greater recognition.
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Abstract
Dispersed pancreatic islet cells were analyzed for their low forward angle light scatter using flow cytometry. The cells produced a distinct light scatter pattern which appeared to be a function of cell size and not cell granularity. RIA of hormone content of cells collected from different regions of the pattern revealed that glucagon- and somatostatin-containing cells were concentrated in regions of lower scatter intensity and that insulin-containing cells were more numerous in regions of higher intensity. Relative to the original cell suspension, these preparations were enriched 3-fold in glucagon and somatostatin content and 6-fold in insulin content. The function of intact islets, unsorted dispersed cells, and sorted dispersed cells was examined before and after 4 days of culture. Before culture, all of the dispersed cell populations had elevated basal secretion compared with intact islets and did not respond to stimulatory concentrations of glucose, arginine, or 3-isobutyl-1-methylxanthine. After culture for 4 days, basal secretion fell, and responsiveness returned. In both the A/D cell-enriched and the B cell-enriched cultured populations, the percentage of single cells was approximately 95%. The insulin release patterns from these populations were similar to those from intact islets and unsorted dispersed cells. Glucagon release from all of the dispersed cell populations far exceeded that from intact islets. This study suggests that the structural organization of islets influences A cell function, but a clear influence upon B cell function has not been demonstrated.
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Da Silva AS, Goldberg A, Barras E, Orlandi VL, Salles JM, Brentani RR. Pharmacological inhibition of hormonal tyrosine amino transferase induction. Biochem Pharmacol 1974; 23:2455-7. [PMID: 4154751 DOI: 10.1016/0006-2952(74)90239-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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