1
|
Pierzchala K, Simicic D, Sienkiewicz A, Sessa D, Mitrea S, Braissant O, McLin VA, Gruetter R, Cudalbu C. Corrigendum to "Central nervous system and systemic oxidative stress interplay with inflammation in a bile duct ligation rat model of type C hepatic encephalopathy" [Free Radical Biol. Med. 178 (2022) 295-307 ISSN 0891-5849]. Free Radic Biol Med 2022; 182:289. [PMID: 35078692 DOI: 10.1016/j.freeradbiomed.2022.01.016] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- K Pierzchala
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Laboratory of Functional and Metabolic Imaging, EPFL, Lausanne, Switzerland.
| | - D Simicic
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Laboratory of Functional and Metabolic Imaging, EPFL, Lausanne, Switzerland
| | - A Sienkiewicz
- Laboratory for Quantum Magnetism, Institute of Physics, EPFL, Lausanne, Switzerland; ADSresonances Sàrl, Préverenges, Switzerland
| | - D Sessa
- Swiss Pediatric Liver Center, Department of Pediatrics, Gynecology and Obstetrics, University Hospitals Geneva and University of Geneva, Geneva, Switzerland
| | - S Mitrea
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - O Braissant
- Service of Clinical Chemistry, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - V A McLin
- Swiss Pediatric Liver Center, Department of Pediatrics, Gynecology and Obstetrics, University Hospitals Geneva and University of Geneva, Geneva, Switzerland
| | - R Gruetter
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Laboratory of Functional and Metabolic Imaging, EPFL, Lausanne, Switzerland
| | - C Cudalbu
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| |
Collapse
|
2
|
Pierzchala K, Simicic D, Sienkiewicz A, Sessa D, Mitrea S, Braissant O, McLin VA, Gruetter R, Cudalbu C. Central nervous system and systemic oxidative stress interplay with inflammation in a bile duct ligation rat model of type C hepatic encephalopathy. Free Radic Biol Med 2022; 178:295-307. [PMID: 34890769 DOI: 10.1016/j.freeradbiomed.2021.12.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/12/2021] [Accepted: 12/06/2021] [Indexed: 02/07/2023]
Abstract
The role and coexistence of oxidative stress (OS) and inflammation in type C hepatic encephalopathy (C HE) is a subject of intense debate. Under normal conditions the physiological levels of intracellular reactive oxygen species are controlled by the counteracting antioxidant response to maintain redox homeostasis. Our previous in-vivo1H-MRS studies revealed the longitudinal impairment of the antioxidant system (ascorbate) in a bile-duct ligation (BDL) rat model of type C HE. Therefore, the aim of this work was to examine the course of central nervous system (CNS) OS and systemic OS, as well as to check for their co-existence with inflammation in the BDL rat model of type C HE. To this end, we implemented a multidisciplinary approach, including ex-vivo and in-vitro electron paramagnetic resonance spectroscopy (EPR) spin-trapping, which was combined with UV-Vis spectroscopy, and histological assessments. We hypothesized that OS and inflammation act synergistically in the pathophysiology of type C HE. Our findings point to an increased CNS- and systemic-OS and inflammation over the course of type C HE progression. In particular, an increase in the CNS OS was observed as early as 2-weeks post-BDL, while the systemic OS became significant at week 6 post-BDL. The CNS EPR measurements were further validated by a substantial accumulation of 8-Oxo-2'-deoxyguanosine (Oxo-8-dG), a marker of oxidative DNA/RNA modifications on immunohistochemistry (IHC). Using IHC, we also detected increased synthesis of antioxidants, glutathione peroxidase 1 (GPX-1) and superoxide dismutases (i.e.Cu/ZnSOD (SOD1) and MnSOD (SOD2)), along with proinflammatory cytokine interleukin-6 (IL-6) in the brains of BDL rats. The presence of systemic inflammation was observed already at 2-weeks post-surgery. Thus, these results suggest that CNS OS is an early event in type C HE rat model, which seems to precede systemic OS. Finally, our results suggest that the increase in CNS OS is due to enhanced formation of intra- and extra-cellular ROS rather than due to reduced antioxidant capacity, and that OS in parallel with inflammation plays a significant role in type C HE.
Collapse
Affiliation(s)
- K Pierzchala
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Laboratory of Functional and Metabolic Imaging, EPFL, Lausanne, Switzerland.
| | - D Simicic
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; Laboratory of Functional and Metabolic Imaging, EPFL, Lausanne, Switzerland
| | - A Sienkiewicz
- Laboratory for Quantum Magnetism, Institute of Physics, EPFL, Lausanne, Switzerland; ADSresonances Sàrl, Préverenges, Switzerland
| | - D Sessa
- Swiss Pediatric Liver Center, Department of Pediatrics, Gynecology and Obstetrics, University Hospitals Geneva and University of Geneva, Geneva, Switzerland
| | - S Mitrea
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - O Braissant
- Service of Clinical Chemistry, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - V A McLin
- Swiss Pediatric Liver Center, Department of Pediatrics, Gynecology and Obstetrics, University Hospitals Geneva and University of Geneva, Geneva, Switzerland
| | - R Gruetter
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Laboratory of Functional and Metabolic Imaging, EPFL, Lausanne, Switzerland
| | - C Cudalbu
- Center for Biomedical Imaging, EPFL, Lausanne, Switzerland; Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| |
Collapse
|
3
|
Bravo D, Braissant O. Cadmium-tolerant bacteria: current trends and applications in agriculture. Lett Appl Microbiol 2021; 74:311-333. [PMID: 34714944 PMCID: PMC9299123 DOI: 10.1111/lam.13594] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/28/2021] [Accepted: 10/15/2021] [Indexed: 12/17/2022]
Abstract
Cadmium (Cd) is considered a toxic heavy metal; nevertheless, its toxicity fluctuates for different organisms. Cadmium-tolerant bacteria (CdtB) are diverse and non-phylogenetically related. Because of their ecological importance these bacteria become particularly relevant when pollution occurs and where human health is impacted. The aim of this review is to show the significance, culturable diversity, metabolic detoxification mechanisms of CdtB and their current uses in several bioremediation processes applied to agricultural soils. Further discussion addressed the technological devices and the possible advantages of genetically modified CdtB for diagnostic purposes in the future.
Collapse
Affiliation(s)
- D Bravo
- Laboratory of Soil Microbiology & Calorimetry, Corporación Colombiana de Investigación Agropecuaria AGROSAVIA, Mosquera, Colombia
| | - O Braissant
- Department of Biomedical Engineering, Faculty of Medicine, University of Basel, Allschwill, Switzerland
| |
Collapse
|
4
|
Braissant O, Theron G, Friedrich SO, Diacon AH, Bonkat G. Comparison of isothermal microcalorimetry and BACTEC MGIT960 for the detection of the metabolic activity of Mycobacterium tuberculosis in sputum samples. J Appl Microbiol 2019; 128:1497-1502. [PMID: 31834654 DOI: 10.1111/jam.14549] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [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: 05/02/2019] [Revised: 11/19/2019] [Accepted: 12/08/2019] [Indexed: 02/04/2023]
Abstract
INTRODUCTION This study explores the uses of microcalorimetry to detect Mycobacterium tuberculosis (TB) in sputum. Microcalorimetry measures metabolic heat evolution during cellular proliferation of tuberculosis (TB) and is considered as a possible alternative to conventional diagnostic tools. OBJECTIVES To compare the time to detection (TTD) from the BACTEC™ MGIT™ 960 and the calScreener™ calorimetric system. METHODS Sixty-four sputa samples were selected from patients with confirmed pulmonary tuberculosis. Those sample were then decontaminated and analysed using calorimetry and BACTEC MGIT 960 system. RESULTS The incubation period until detection of M. tuberculosis in the sample was 8·5 ± 3·7 days for the MGIT system and 10·1 ± 4·1 days (mean ± SD) for calorimetry. CONCLUSIONS The microincubations in the 48-well format calScreener offers potential for rapid and accurate diagnostic of TB in different samples. Although TTD from calorimetry is still longer than with the MGIT, our findings suggest that several improvements are possible. Still, the instrument is ideal for continuous, real-time analysis of net metabolic heat release of limited sample numbers. SIGNIFICANCE AND IMPACT OF THE STUDY Our result emphasizes that with further optimization, calorimetry can become an alternative detection method for tuberculosis.
Collapse
Affiliation(s)
- O Braissant
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - G Theron
- TASK Applied Science, Bellville, Cape Town, South Africa
| | - S O Friedrich
- TASK Applied Science, Bellville, Cape Town, South Africa.,Division of Medical Physiology, Faculty of Medicine and Health Sciences, MRC Centre for Tuberculosis Research, Stellenbosch University, Tygerberg, South Africa
| | - A H Diacon
- TASK Applied Science, Bellville, Cape Town, South Africa.,Division of Medical Physiology, Faculty of Medicine and Health Sciences, MRC Centre for Tuberculosis Research, Stellenbosch University, Tygerberg, South Africa
| | - G Bonkat
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland.,Alta-Uro AG, Basel, Switzerland
| |
Collapse
|
5
|
Pace A, Bourillot R, Bouton A, Vennin E, Braissant O, Dupraz C, Duteil T, Bundeleva I, Patrier P, Galaup S, Yokoyama Y, Franceschi M, Virgone A, Visscher PT. Formation of stromatolite lamina at the interface of oxygenic-anoxygenic photosynthesis. Geobiology 2018; 16:378-398. [PMID: 29573198 DOI: 10.1111/gbi.12281] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 02/13/2018] [Indexed: 06/08/2023]
Abstract
In modern stromatolites, mineralization results from a complex interplay between microbial metabolisms, the organic matrix, and environmental parameters. Here, we combined biogeochemical, mineralogical, and microscopic analyses with measurements of metabolic activity to characterize the mineralization processes and products in an emergent (<18 months) hypersaline microbial mat. While the nucleation of Mg silicates is ubiquitous in the mat, the initial formation of a Ca-Mg carbonate lamina depends on (i) the creation of a high-pH interface combined with a major change in properties of the exopolymeric substances at the interface of the oxygenic and anoxygenic photoautotrophic layers and (ii) the synergy between two major players of sulfur cycle, purple sulfur bacteria, and sulfate-reducing bacteria. The repetition of this process over time combined with upward growth of the mat is a possible pathway leading to the formation of a stromatolite.
Collapse
Affiliation(s)
- A Pace
- EA 4592, Géoressources & Environnement, Ensegid, Bordeaux INP, Pessac, France
- Université Bordeaux Montaigne, Pessac, France
| | - R Bourillot
- EA 4592, Géoressources & Environnement, Ensegid, Bordeaux INP, Pessac, France
| | - A Bouton
- Laboratoire Biogéosciences, UMR 6282 UBFC/CNRS, Université Bourgogne Franche-Comté, Dijon, France
- Total, CSTJF, Pau, France
| | - E Vennin
- Laboratoire Biogéosciences, UMR 6282 UBFC/CNRS, Université Bourgogne Franche-Comté, Dijon, France
| | - O Braissant
- Center for Biomechanics and Biocalorimetry, University of Basel, Basel, Switzerland
| | - C Dupraz
- Department of Geological Sciences, Stockholm University, Stockholm, Sweden
| | - T Duteil
- EA 4592, Géoressources & Environnement, Ensegid, Bordeaux INP, Pessac, France
| | - I Bundeleva
- Laboratoire Biogéosciences, UMR 6282 UBFC/CNRS, Université Bourgogne Franche-Comté, Dijon, France
| | - P Patrier
- UMR 7285 CNRS IC2MP, Université de Poitiers, Poitiers, France
| | - S Galaup
- EA 4592, Géoressources & Environnement, Ensegid, Bordeaux INP, Pessac, France
| | - Y Yokoyama
- Department of Earth and Planetary Sciences, Atmosphere and Ocean Research Institute, University of Tokyo, Chiba, Japan
| | - M Franceschi
- EA 4592, Géoressources & Environnement, Ensegid, Bordeaux INP, Pessac, France
| | | | - P T Visscher
- Department of Marine Sciences, University of Connecticut, Groton, CT, USA
| |
Collapse
|
6
|
Gysin M, Braissant O, Gillingwater K, Brun R, Mäser P, Wenzler T. Isothermal microcalorimetry - A quantitative method to monitor Trypanosoma congolense growth and growth inhibition by trypanocidal drugs in real time. Int J Parasitol Drugs Drug Resist 2018; 8:159-164. [PMID: 29587237 PMCID: PMC6039311 DOI: 10.1016/j.ijpddr.2018.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/14/2018] [Accepted: 03/13/2018] [Indexed: 11/18/2022]
Abstract
Trypanosoma congolense is a protozoan parasite that is transmitted by tsetse flies, causing African Animal Trypanosomiasis, also known as Nagana, in sub-Saharan Africa. Nagana is a fatal disease of livestock that causes severe economic losses. Two drugs are available, diminazene and isometamidium, yet successful treatment is jeopardized by drug resistant T. congolense. Isothermal microcalorimetry is a highly sensitive tool that can be used to study growth of the extracellular T. congolense parasites or to study parasite growth inhibition after the addition of antitrypanosomal drugs. Time of drug action and time to kill can be quantified in a simple way by real time heat flow measurements. We established a robust protocol for the microcalorimetric studies of T. congolense and developed mathematical computations in R to calculate different parameters related to growth and the kinetics of drug action. We demonstrate the feasibility and benefit of the method exemplary with the two standard drugs, diminazene aceturate and isometamidium chloride. The method and the mathematical approach can be translated to study other pathogenic or non-pathogenic cells if they are metabolically active and grow under axenic conditions. Isothermal microcalorimetry enables heat flow measurement of T. congolense in real-time. Heat flow measurements correlate with number of viable cells. Growth and drug-induced growth inhibition can be deducted from heat flow curves. Pharmacodynamic drug action parameters can be computed from heat flow curves. This method is a valuable tool in the drug discovery process against T. congolense.
Collapse
Affiliation(s)
- M Gysin
- Medical Parasitology & Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland; University of Basel, Petersplatz 1, 4001, Basel, Switzerland
| | - O Braissant
- Center of Biomechanics & Biocalorimetry, University of Basel, Gewerbestrasse 14, Allschwil, 4123, Switzerland
| | - K Gillingwater
- Medical Parasitology & Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland; University of Basel, Petersplatz 1, 4001, Basel, Switzerland
| | - R Brun
- Medical Parasitology & Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland; University of Basel, Petersplatz 1, 4001, Basel, Switzerland
| | - P Mäser
- Medical Parasitology & Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland; University of Basel, Petersplatz 1, 4001, Basel, Switzerland
| | - T Wenzler
- Medical Parasitology & Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland; University of Basel, Petersplatz 1, 4001, Basel, Switzerland.
| |
Collapse
|
7
|
Bravo D, Pardo‐Díaz S, Benavides‐Erazo J, Rengifo‐Estrada G, Braissant O, Leon‐Moreno C. Cadmium and cadmium‐tolerant soil bacteria in cacao crops from northeastern Colombia. J Appl Microbiol 2018; 124:1175-1194. [DOI: 10.1111/jam.13698] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 12/14/2017] [Accepted: 01/09/2018] [Indexed: 11/30/2022]
Affiliation(s)
- D. Bravo
- Laboratory of Soil Microbiology and Calorimetry Corporación Colombiana de Investigación Agropecuaria – Corpoica Centro de Investigación Tibaitatá – kilómetro 14 vía Mosquera‐Bogotá Cundinamarca Colombia
| | - S. Pardo‐Díaz
- Laboratory of Soil Microbiology and Calorimetry Corporación Colombiana de Investigación Agropecuaria – Corpoica Centro de Investigación Tibaitatá – kilómetro 14 vía Mosquera‐Bogotá Cundinamarca Colombia
| | | | - G. Rengifo‐Estrada
- Corporación Colombiana de Investigación Agropecuaria – Corpoica, Centro de Investigación La Suiza – kilómetro 32 vía al mar vereda Galápagos Rionegro Santander Colombia
| | - O. Braissant
- Center of Biomechanics & Calorimetry Basel (COB) University of Basel Basel Switzerland
| | - C. Leon‐Moreno
- Corporación Colombiana de Investigación Agropecuaria – Corpoica, Centro de Investigación La Suiza – kilómetro 32 vía al mar vereda Galápagos Rionegro Santander Colombia
| |
Collapse
|
8
|
Brueckner D, Krähenbühl S, Zuber U, Bonkat G, Braissant O. An alternative sterility assessment for parenteral drug products using isothermal microcalorimetry. J Appl Microbiol 2017; 123:773-779. [PMID: 28776899 DOI: 10.1111/jam.13520] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [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: 02/15/2017] [Revised: 04/19/2017] [Accepted: 06/19/2017] [Indexed: 11/29/2022]
Abstract
AIMS Production and release of injectable drug solutions are highly regulated since the administration of injectables bypasses natural body barriers. The sterility test is the last opportunity of product quality assessment. However, sterility is currently assessed by visual inspection (VI) that is time consuming and somewhat subjective. Therefore, we assessed isothermal microcalorimetry (IMC) as a replacement for the VI of the filtration based state-of-the-art sterility control. METHODS AND RESULTS We used ATCC strains and house isolates to artificially contaminate frequently produced monoclonal antibodies (Avastin, Mabthera, Herceptin). After filtration, growth was assessed with IMC. Growth of all micro-organisms was reliably and reproducibly detected 4 days after inoculation, which was significantly faster than with VI. CONCLUSIONS The reliability and the sensitivity of IMC have a large potential to improve sterility controls. Further evaluation of this alternative method is therefore highly recommended. SIGNIFICANCE AND IMPACT OF THE STUDY Drug safety is of great concern for public health. Faster and safer drug production could be achieved using the technique described here. All the tests were performed with real manufactured drugs and complied with pharmaceutical standards. This suggests that drug sterility testing can be improved with potentially increased safety and cost reduction.
Collapse
Affiliation(s)
- D Brueckner
- Center of Biomechanics and Biocalorimetry, University of Basel, Allschwil, Switzerland.,Sterile Drug Product Manufacturing, F. Hoffmann - La Roche Ltd, Kaiseraugst, Switzerland
| | - S Krähenbühl
- Clinical Pharmacology & Toxicology, Universitätsspital Basel, Basel, Switzerland
| | - U Zuber
- Sterile Drug Product Manufacturing, F. Hoffmann - La Roche Ltd, Kaiseraugst, Switzerland
| | | | - O Braissant
- Center of Biomechanics and Biocalorimetry, University of Basel, Allschwil, Switzerland.,Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| |
Collapse
|
9
|
Sforna MC, Daye M, Philippot P, Somogyi A, van Zuilen MA, Medjoubi K, Gérard E, Jamme F, Dupraz C, Braissant O, Glunk C, Visscher PT. Patterns of metal distribution in hypersaline microbialites during early diagenesis: Implications for the fossil record. Geobiology 2017; 15:259-279. [PMID: 27935656 DOI: 10.1111/gbi.12218] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 09/28/2016] [Indexed: 06/06/2023]
Abstract
The use of metals as biosignatures in the fossil stromatolite record requires understanding of the processes controlling the initial metal(loid) incorporation and diagenetic preservation in living microbialites. Here, we report the distribution of metals and the organic fraction within the lithifying microbialite of the hypersaline Big Pond Lake (Bahamas). Using synchrotron-based X-ray microfluorescence, confocal, and biphoton microscopies at different scales (cm-μm) in combination with traditional geochemical analyses, we show that the initial cation sorption at the surface of an active microbialite is governed by passive binding to the organic matrix, resulting in a homogeneous metal distribution. During early diagenesis, the metabolic activity in deeper microbialite layers slows down and the distribution of the metals becomes progressively heterogeneous, resulting from remobilization and concentration as metal(loid)-enriched sulfides, which are aligned with the lamination of the microbialite. In addition, we were able to identify globules containing significant Mn, Cu, Zn, and As enrichments potentially produced through microbial activity. The similarity of the metal(loid) distributions observed in the Big Pond microbialite to those observed in the Archean stromatolites of Tumbiana provides the foundation for a conceptual model of the evolution of the metal distribution through initial growth, early diagenesis, and fossilization of a microbialite, with a potential application to the fossil record.
Collapse
Affiliation(s)
- M C Sforna
- Geobiosphère Actuelle & Primitive, Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, CNRS, Paris, France
- Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, Modena, Italy
| | - M Daye
- Geobiosphère Actuelle & Primitive, Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, CNRS, Paris, France
- Synchrotron Soleil, Gif-sur-Yvette, France
| | - P Philippot
- Geobiosphère Actuelle & Primitive, Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, CNRS, Paris, France
| | - A Somogyi
- Synchrotron Soleil, Gif-sur-Yvette, France
| | - M A van Zuilen
- Geomicrobiologie, Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, CNRS, Paris, France
| | - K Medjoubi
- Synchrotron Soleil, Gif-sur-Yvette, France
| | - E Gérard
- Geomicrobiologie, Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, CNRS, Paris, France
| | - F Jamme
- Synchrotron Soleil, Gif-sur-Yvette, France
| | - C Dupraz
- Department of Geological Sciences, Stockholms Universitet, Stockholm, Sweden
| | - O Braissant
- Center for Biomechanics and Biocalorimetry, University of Basel, Basel, Switzerland
| | - C Glunk
- Societe Suisse des Explosifs SA, Brig, Switzerland
| | - P T Visscher
- Department of Marine Sciences, University of Connecticut, Groton, CT, USA
| |
Collapse
|
10
|
Bonkat G, Müller G, Berini A, Frei R, Goldenberger D, Regeniter A, Rieken M, Braissant O, Gasser T, Bachmann A, Egli A. 456 Combination of matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) and UX-2000 urine flow-cytometry for rapid detection and identification of urinary tract pathogens. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/s1569-9056(14)60450-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
11
|
Gremlich S, Damnon F, Reymondin D, Braissant O, Schittny JC, Baud D, Gerber S, Roth-Kleiner M. The long non-coding RNA NEAT1 is increased in IUGR placentas, leading to potential new hypotheses of IUGR origin/development. Placenta 2013; 35:44-9. [PMID: 24280234 DOI: 10.1016/j.placenta.2013.11.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 11/04/2013] [Accepted: 11/05/2013] [Indexed: 02/04/2023]
Abstract
INTRODUCTION Intrauterine Growth Restriction (IUGR) is a multifactorial disease defined by an inability of the fetus to reach its growth potential. IUGR not only increases the risk of neonatal mortality/morbidity, but also the risk of metabolic syndrome during adulthood. Certain placental proteins have been shown to be implicated in IUGR development, such as proteins from the GH/IGF axis and angiogenesis/apoptosis processes. METHODS Twelve patients with term IUGR pregnancy (birth weight < 10th percentile) and 12 CTRLs were included. mRNA was extracted from the fetal part of the placenta and submitted to a subtraction method (Clontech PCR-Select cDNA Subtraction). RESULTS One candidate gene identified was the long non-coding RNA NEAT1 (nuclear paraspeckle assembly transcript 1). NEAT1 is the core component of a subnuclear structure called paraspeckle. This structure is responsible for the retention of hyperedited mRNAs in the nucleus. Overall, NEAT1 mRNA expression was 4.14 (±1.16)-fold increased in IUGR vs. CTRL placentas (P = 0.009). NEAT1 was exclusively localized in the nuclei of the villous trophoblasts and was expressed in more nuclei and with greater intensity in IUGR placentas than in CTRLs. PSPC1, one of the three main proteins of the paraspeckle, co-localized with NEAT1 in the villous trophoblasts. The expression of NEAT1_2 mRNA, the long isoform of NEAT1, was only modestly increased in IUGR vs. CTRL placentas. DISCUSSION/CONCLUSION The increase in NEAT1 and its co-localization with PSPC1 suggests an increase in paraspeckles in IUGR villous trophoblasts. This could lead to an increased retention of important mRNAs in villous trophoblasts nuclei. Given that the villous trophoblasts are crucial for the barrier function of the placenta, this could in part explain placental dysfunction in idiopathic IUGR fetuses.
Collapse
Affiliation(s)
- S Gremlich
- Clinic of Neonatology, University Hospital and University of Lausanne, Switzerland.
| | - F Damnon
- Department of Gynecology, Obstetrics and Medical Genetics, University Hospital and University of Lausanne, Switzerland
| | - D Reymondin
- Department of Gynecology, Obstetrics and Medical Genetics, University Hospital and University of Lausanne, Switzerland
| | - O Braissant
- Service of Biomedicine, University Hospital and University of Lausanne, Switzerland
| | - J C Schittny
- Institute of Anatomy, University of Bern, Switzerland
| | - D Baud
- Department of Gynecology, Obstetrics and Medical Genetics, University Hospital and University of Lausanne, Switzerland
| | - S Gerber
- Department of Gynecology, Obstetrics and Medical Genetics, University Hospital and University of Lausanne, Switzerland
| | - M Roth-Kleiner
- Clinic of Neonatology, University Hospital and University of Lausanne, Switzerland
| |
Collapse
|
12
|
Wernli L, Bonkat G, Gasser T, Bachmann A, Braissant O. Use of isothermal microcalorimetry to quantify the influence of glucose and antifungals on the growth of Candida albicans
in urine. J Appl Microbiol 2013; 115:1186-93. [DOI: 10.1111/jam.12306] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 07/11/2013] [Accepted: 07/11/2013] [Indexed: 01/15/2023]
Affiliation(s)
- L. Wernli
- Department of Urology; University Hospital Basel; Basel Switzerland
| | - G. Bonkat
- Department of Urology; University Hospital Basel; Basel Switzerland
- Laboratory of Biomechanics and Biocalorimetry (LOB2); Faculty of Medicine; University of Basel; Basel Switzerland
| | - T.C. Gasser
- Department of Urology; University Hospital Basel; Basel Switzerland
| | - A. Bachmann
- Department of Urology; University Hospital Basel; Basel Switzerland
| | - O. Braissant
- Department of Urology; University Hospital Basel; Basel Switzerland
- Laboratory of Biomechanics and Biocalorimetry (LOB2); Faculty of Medicine; University of Basel; Basel Switzerland
| |
Collapse
|
13
|
Bonkat G, Wernli L, Braissant O, Rieken M, Müller G, Wyler S, Gasser T, Bachmann A. 618 Growth quantification and rapid drug susceptibility testing of uropathogenic Candida albicans by isothermal microcalorimetry. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/s1569-9056(13)61101-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
14
|
Bonkat G, Müller G, Braissant O, Frei R, Tschudin-Suter S, Rieken M, Wyler S, Gasser TC, Bachmann A, Widmer AF. Increasing prevalence of ciprofloxacin resistance in extended-spectrum-β-lactamase-producing Escherichia coli urinary isolates. World J Urol 2013; 31:1427-32. [DOI: 10.1007/s00345-013-1031-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 01/20/2013] [Indexed: 01/02/2023] Open
|
15
|
Gallagher KL, Kading TJ, Braissant O, Dupraz C, Visscher PT. Inside the alkalinity engine: the role of electron donors in the organomineralization potential of sulfate-reducing bacteria. Geobiology 2012; 10:518-530. [PMID: 22925453 DOI: 10.1111/j.1472-4669.2012.00342.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/19/2012] [Indexed: 06/01/2023]
Abstract
Mineral precipitation in microbial mats may have been the key to their preservation as fossil stromatolites, potentially documenting evidence of the earliest life on Earth. Two factors that contribute to carbonate mineral precipitation are the saturation index (SI) and the presence of nucleation sites. Both of these can be influenced by micro-organisms, which can either alter SI through their metabolisms, or produce and consume organic substances such as extracellular polymeric substances (EPS) that can affect nucleation. It is the balance of individual metabolisms within the mat community that determines the pH and the dissolved inorganic carbon concentration, thereby potentially increasing the alkalinity and consequently the SI. Sulfate-reducing bacteria (SRB) are an important component of this 'alkalinity engine.' The activity of SRB often peaks in layers where CaCO(3) precipitates, and mineral precipitation has been demonstrated in SRB cultures; however, the effect of their metabolism on the alkalinity engine and actual contribution to mineral precipitation is the subject of controversy. Here, we show through culture experiments, theoretical calculations, and geochemical modeling studies that the pH, alkalinity, and organomineralization potential will vary depending on the type of electron donor. Specifically, hydrogen and formate can increase the pH, but electron donors like lactate and ethanol, and to a lesser extent glycolate, decrease the pH. The implication of this for the lithification of mats is that the combination of processes supplying electron donors and the utilization of these compounds by SRB may be critical to promoting mineral precipitation.
Collapse
Affiliation(s)
- K L Gallagher
- Department of Marine Sciences, University of Connecticut, Groton, CT, USA
| | | | | | | | | |
Collapse
|
16
|
Bonkat G, Braissant O, Rieken M, Müller G, Frei R, van der Merwe A, Siegel FP, Gasser TC, Wyler S, Bachmann A, Widmer AF. Comparison of the roll-plate and sonication techniques in the diagnosis of microbial ureteral stent colonisation: results of the first prospective randomised study. World J Urol 2012; 31:579-84. [PMID: 23053214 DOI: 10.1007/s00345-012-0963-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 09/22/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Microbial ureteral stent colonisation (MUSC) is one leading risk factor for complications associated with ureteral stent placement. As MUSC remains frequently undetected by standard urine cultures, its definitive diagnosis depends on microbiological investigation of the stent. However, a standard reference laboratory technique for studying MUSC is still lacking. MATERIALS AND METHODS A total of 271 ureteral stents removed from 199 consecutive patients were investigated. Urine samples were obtained prior to device removal. Stents were divided into four parts. Each part was separately processed by the microbiology laboratory within 6 h. Ureteral stents were randomly allocated to roll-plate or sonication, respectively, and analysed using standard microbiological techniques. Demographic and clinical data were prospectively collected using a standard case-report form. RESULTS Overall, roll-plate showed a higher detection rate of MUSC compared with sonication (35 vs. 28 %, p < 0.05) and urine culture (35 vs. 8 %, p < 0.05). No inferiority of Maki's technique was observed even when stents were stratified according to indwelling time below or above 30 days. Compared with roll-plate, sonication commonly failed to detect Enterococcus spp., coagulase-negative staphylococci (CoNS) and Enterobacteriaceae. In addition, sonication required more hands-on time, more equipment and higher training than roll-plate in the laboratory. CONCLUSIONS This prospective randomised study demonstrates the superiority of Maki's roll-plate technique over sonication in the diagnosis of MUSC and that urine culture is less sensitive than both methods. The higher detection rate, simplicity and cost-effectiveness render roll-plate the methodology of choice for routine clinical investigation as well as basic laboratory research.
Collapse
Affiliation(s)
- G Bonkat
- Department of Urology, University Hospital Basel, Spitalstrasse 21, 4031, Basel, Switzerland.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Doostmohammadi A, Monshi A, Fathi MH, Karbasi S, Braissant O, Daniels AU. Direct cytotoxicity evaluation of 63S bioactive glass and bone-derived hydroxyapatite particles using yeast model and human chondrocyte cells by microcalorimetry. J Mater Sci Mater Med 2011; 22:2293-2300. [PMID: 21786131 DOI: 10.1007/s10856-011-4400-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 07/14/2011] [Indexed: 05/31/2023]
Abstract
In this study, the cytotoxicity evaluation of prepared 63S bioactive glass and bone-derived hydroxyapatite particles with yeast and human chondrocyte cells was carried out using isothermal micro-nano calorimetry (IMNC), which is a new method for studying cell/biomaterial interactions. Bioactive glass particles were made via sol-gel method and hydroxyapatite was obtained from bovine bone. Elemental analysis was carried out by XRF and EDXRF. Amorphous structure of the glass and completely crystalline structure of HA were detected by XRD analysis. Finally, the cytotoxicity of bioactive glass and bone-derived HA particles with yeast and cultured human chondrocyte cells was evaluated using IMNC. The results confirmed the viability, growth and proliferation of human chondrocyte cells in contact with 63S bioactive glass, and bone-derived HA particles. Also the results indicated that yeast model which is much easier to handle, can be considered as a good proxy and can provide a rapid primary estimate of the ranges to be used in assays involving human cells. All of these results confirmed that IMNC is a convenient method which caters to measuring the cell-biomaterial interactions alongside the current methods.
Collapse
Affiliation(s)
- A Doostmohammadi
- Biomaterials Group, Materials Engineering Department, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
| | | | | | | | | | | |
Collapse
|
18
|
Santoro R, Braissant O, Müller B, Wirz D, Daniels A, Martin I, Wendt D. Real-time measurements of human chondrocyte heat production during in vitro proliferation. Biotechnol Bioeng 2011; 108:3019-24. [DOI: 10.1002/bit.23268] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 05/31/2011] [Accepted: 07/08/2011] [Indexed: 11/08/2022]
|
19
|
Rodríguez D, Daniels AU, Urrusti JL, Wirz D, Braissant O. Evaluation of a low-cost calorimetric approach for rapid detection of tuberculosis and other mycobacteria in culture. J Appl Microbiol 2011; 111:1016-24. [PMID: 21797951 DOI: 10.1111/j.1365-2672.2011.05117.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS The objective of this study was to evaluate the effectiveness of microcalorimetry in rapid detection of mycobacterium species using an inexpensive Isothermal microcalorimetry (IMC) instrument. In addition, we compared microcalorimetry with conventional monitoring techniques. METHODS AND RESULTS Isothermal microcalorimetry measures heat production rate and can provide rapid detection of living mycobacteria in clinical specimens. Using liquid medium showed that bacterial activity measured by IMC using a TAM Air® agreed with the triphenyl tetrazolium chloride (TTC) assay. Using solid medium to enhance growth, fast-growing mycobacteria detection was achieved between 26 and 53 h and slow-growing mycobacteria detection was achieved between 54 and 298 h. In addition, the calorimetric data were analysed to estimate the growth rate and generation time of the mycobacteria monitored. SIGNIFICANCE AND IMPACT OF THE STUDY Infections caused by mycobacteria are severe and difficult to treat. With 9·27 million new cases of tuberculosis in 2007, developing countries experience severe health and economic consequences owing to the lack of an affordable, fast detection method. Research-grade IMC instruments are too expensive to use in developing countries. Our study demonstrates that less-expensive instruments such as the TAM air® are adequate for mycobacteria detection and therefore establishes a clear proof of concept.
Collapse
Affiliation(s)
- D Rodríguez
- Department of Engineering, Iberoamericana University at Mexico City, Mexico
| | | | | | | | | |
Collapse
|
20
|
Braissant O, Wirz D, Göpfert B, Daniels A. “The heat is on”: Rapid microcalorimetric detection of mycobacteria in culture. Tuberculosis (Edinb) 2010; 90:57-9. [DOI: 10.1016/j.tube.2009.11.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 11/18/2009] [Indexed: 10/20/2022]
|
21
|
Braissant O, Henry H. AGAT, GAMT and SLC6A8 distribution in the central nervous system, in relation to creatine deficiency syndromes: a review. J Inherit Metab Dis 2008; 31:230-9. [PMID: 18392746 DOI: 10.1007/s10545-008-0826-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 02/01/2008] [Accepted: 02/05/2008] [Indexed: 11/25/2022]
Abstract
Creatine deficiency syndromes, either due to AGAT, GAMT or SLC6A8 deficiencies, lead to a complete absence, or a very strong decrease, of creatine within the brain, as measured by magnetic resonance spectroscopy. While the mammalian central nervous system (CNS) expresses AGAT, GAMT and SLC6A8, the lack of SLC6A8 in astrocytes around the blood-brain barrier limits the brain capacity to import creatine from the periphery, and suggests that the CNS has to rely mainly on endogenous creatine synthesis through AGAT and GAMT expression. This seems contradictory with SLC6A8 deficiency, which, despite AGAT and GAMT expression, also leads to creatine deficiency in the CNS. We present novel data showing that in cortical grey matter, AGAT and GAMT are expressed in a dissociated way: e.g. only a few cells co-express both genes. This suggests that to allow synthesis of creatine within the CNS, at least for a significant part of it, guanidinoacetate must be transported from AGAT- to GAMT-expressing cells, possibly through SLC6A8. This would explain the creatine deficiency observed in SLC6A8-deficient patients. By bringing together creatine deficiency syndromes, AGAT, GAMT and SLC6A8 distribution in CNS, as well as a synthetic view on creatine and guanidinoacetate levels in the brain, this review presents a comprehensive framework, including new hypotheses, on brain creatine metabolism and transport, both in normal conditions and in case of creatine deficiency.
Collapse
Affiliation(s)
- O Braissant
- Inborn Errors of Metabolism, Clinical Chemistry Laboratory, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland.
| | | |
Collapse
|
22
|
Zurich MG, Lengacher S, Braissant O, Monnet-Tschudi F, Pellerin L, Honegger P. Unusual astrocyte reactivity caused by the food mycotoxin ochratoxin A in aggregating rat brain cell cultures. Neuroscience 2005; 134:771-82. [PMID: 15994020 DOI: 10.1016/j.neuroscience.2005.04.030] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [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: 11/28/2004] [Revised: 02/21/2005] [Accepted: 04/13/2005] [Indexed: 11/26/2022]
Abstract
Ochratoxin A (OTA), a mycotoxin and widespread food contaminant, is known for its patent nephrotoxicity and potential neurotoxicity. Previous observations in vitro showed that in the CNS, glial cells were particularly sensitive to OTA. In the search for the molecular mechanisms underlying OTA neurotoxicity, we investigated the relationship between OTA toxicity and glial reactivity, in serum-free aggregating brain cell cultures. Using quantitative reverse transcriptase-polymerase chain reaction to analyze changes in gene expression, we found that in astrocytes, non cytotoxic concentrations of OTA down-regulated glial fibrillary acidic protein, while it up-regulated vimentin and the peroxisome proliferator-activated receptor-gamma expression. OTA also up-regulated the inducible nitric oxide synthase and the heme oxygenase-1. These OTA-induced alterations in gene expression were more pronounced in cultures at an advanced stage of maturation. The natural peroxisome proliferator-activated receptor-gamma ligand, 15-deoxy-delta(12,14) prostaglandin J2, and the cyclic AMP analog, bromo cyclic AMP, significantly attenuated the strong induction of peroxisome proliferator-activated receptor-gamma and inducible nitric oxide synthase, while they partially reversed the inhibitory effect of OTA on glial fibrillary acidic protein. The present results show that OTA affects the cytoskeletal integrity of astrocytes as well as the expression of genes pertaining to the brain inflammatory response system, and suggest that a relationship exists between the inflammatory events and the cytoskeletal changes induced by OTA. Furthermore, these results suggest that, by inducing an atypical glial reactivity, OTA may severely affect the neuroprotective capacity of glial cells.
Collapse
Affiliation(s)
- M-G Zurich
- Department of Physiology, University of Lausanne, Rue du Bugnon 7, CH-1005 Lausanne, Switzerland.
| | | | | | | | | | | |
Collapse
|
23
|
Abstract
PPARs are a family of nuclear hormone receptors involved in various processes that could influence ovarian function. We investigated the cellular localization and expression of PPARs during follicular development in ovarian tissue collected from rats 0, 6, 12, 24, and 48 h post-PMSG. A second group of animals received human CG (hCG) 48 h post-PMSG. Their ovaries were removed 0, 4, 8, 12, and 24 h post-hCG to study the periovulatory period. mRNAs corresponding to the PPAR isotypes (alpha, delta, and gamma) were localized by in situ hybridization. Changes in the levels of mRNA for the PPARs were determined by ribonuclease protection assays. PPAR gamma mRNA was localized primarily to granulosa cells, and levels of expression did not change during follicular development. Four hours post-hCG, levels of mRNA for PPAR gamma decreased (P < 0.05) but not uniformly in all follicles. At 24 h post-hCG, levels of PPAR gamma mRNA were reduced 64%, but some follicles maintained high expression. In contrast, mRNAs for PPAR alpha and delta were located primarily in theca and stroma, and their levels did not change during the intervals studied. To investigate the physiologic significance of PPAR gamma in the ovary, granulosa cells from PMSG-primed rats were cultured for 48 h with prostaglandin J(2) (PGJ(2)) and ciglitazone, PPAR gamma activators. Both compounds increased progesterone and E2 secretion (P < 0.05). These data suggest that PPAR gamma is involved in follicular development, has a negative influence on the luteinization of granulosa cells, and/or regulates the periovulatory shift in steroid production. The more general and steady expression of PPARs alpha and delta indicate that they may play a role in basal ovarian function.
Collapse
Affiliation(s)
- C M Komar
- Department of Obstetrics and Gynecology, Chandler Medical Center, University of Kentucky, Lexington, Kentucky 40536-0298, USA.
| | | | | | | |
Collapse
|
24
|
Escher P, Braissant O, Basu-Modak S, Michalik L, Wahli W, Desvergne B. Rat PPARs: quantitative analysis in adult rat tissues and regulation in fasting and refeeding. Endocrinology 2001; 142:4195-202. [PMID: 11564675 DOI: 10.1210/endo.142.10.8458] [Citation(s) in RCA: 316] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PPARs are members of the nuclear hormone receptor superfamily and are primarily involved in lipid metabolism. The expression patterns of all 3 PPAR isotypes in 22 adult rat organs were analyzed by a quantitative ribonuclease protection assay. The data obtained allowed comparison of the expression of each isotype to the others and provided new insight into the less studied PPAR beta (NR1C2) expression and function. This isotype shows a ubiquitous expression pattern and is the most abundant of the three PPARs in all analyzed tissues except adipose tissue. Its expression is especially high in the digestive tract, in addition to kidney, heart, diaphragm, and esophagus. After an overnight fast, PPAR beta mRNA levels are dramatically down-regulated in liver and kidney by up to 80% and are rapidly restored to control levels upon refeeding. This tight nutritional regulation is independent of the circulating glucocorticoid levels and the presence of PPAR alpha, whose activity is markedly up-regulated in the liver and small intestine during fasting. Finally, PPAR gamma 2 mRNA levels are decreased by 50% during fasting in both white and brown adipose tissue. In conclusion, fasting can strongly influence PPAR expression, but in only a few selected tissues.
Collapse
Affiliation(s)
- P Escher
- Institut de Biologie Animale, Université de Lausanne, CH-1015 Lausanne, Switzerland
| | | | | | | | | | | |
Collapse
|
25
|
Braissant O, Gotoh T, Loup M, Mori M, Bachmann C. Differential expression of the cationic amino acid transporter 2(B) in the adult rat brain. Brain Res Mol Brain Res 2001; 91:189-95. [PMID: 11457509 DOI: 10.1016/s0169-328x(01)00113-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
L-Arginine is a substrate for the synthesis of proteins, nitric oxide (NO), creatine, urea, proline, glutamate, polyamines and agmatine. In the central nervous system (CNS), arginine is extracted from the blood and exchanged by cells through carriers called cationic amino acid transporters (CAT) and belonging to the so-called system y+. In order to better understand the arginine transport in the CNS, we studied in detail the regional distribution of the cells expressing the CAT2(B) transcript in the adult rat brain by non-radioisotopic in situ hybridization. We show that CAT2(B) is expressed in neurons and oligodendrocytes throughout the brain, but is not detected in astrocytes. The pattern of localization of CAT2(B) in the normal adult rat brain fits closely that of CRT1, a specific creatine transporter. Our study demonstrates that the in vivo expression of CAT2(B) differs from that reported in vitro, implying that local cellular interactions should be taken into account in studies of gene regulation of the CAT2(B) gene. Our work suggests that CAT2(B) may play a role in case of increased NO production as well as arginine or creatine deficiency in the brain.
Collapse
Affiliation(s)
- O Braissant
- Central Clinical Chemistry Laboratory, University Hospital, CH-1011, Lausanne, Switzerland.
| | | | | | | | | |
Collapse
|
26
|
Haefliger JA, Demotz S, Braissant O, Suter E, Waeber B, Nicod P, Meda P. Connexins 40 and 43 are differentially regulated within the kidneys of rats with renovascular hypertension. Kidney Int 2001; 60:190-201. [PMID: 11422751 DOI: 10.1046/j.1523-1755.2001.00786.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Connexin 40 (Cx40) is a gap junction protein expressed in endothelial cells of vessels, endocardium, and conducting cells of the His-Purkinje system of heart. Its distribution in the kidney remains to be fully investigated. METHODS To address this distribution, we generated rabbit antibodies directed to a polypeptide comprising amino acids 231 to 330 of the carboxy-terminal domain of rodent Cx40, which specifically recognizes this protein at gap junctions. RESULTS Immunolabeling and in situ hybridization of kidney sections showed that Cx40 and its transcript were coexpressed by most endothelial cells of vessels and glomeruli, as well as by renin-secreting cells. This distribution contrasted with that of Cx43, which was expressed in some tubules of medulla and sparse endothelial cells. Cx40 and Cx43 expression were investigated further in a renin-dependent model of hypertension, in which rats showed an increase in arterial mean blood pressure four weeks after clipping one renal artery [two kidney, one-clip (2K1C) model]. Northern blot analysis of polyA+ RNA demonstrated that, compared with sham-operated animals, the hypertensive 2K1C animals featured an increase in Cx40 mRNA expression in both left (clipped) and right (unclipped) kidneys. In contrast, Cx43 mRNA expression was only increased in the latter organ. Antibodies confirmed that the levels of Cx40 were actually increased in the kidneys of hypertensive animals (Western blots) and this was caused, at least in part, by enhanced expression of this protein in the renin-secreting cells of the afferent arteriole (immunofluorescence). CONCLUSIONS Cell-to-cell communication mediated by Cx40 may be implicated in the function of renin-secreting cells, hence participating in the control of blood pressure.
Collapse
Affiliation(s)
- J A Haefliger
- Department of Internal Medicine, Laboratory of Clinical Chemistry, Division of Physiopathology, University Hospital, Lausanne, Switzerland.
| | | | | | | | | | | | | |
Collapse
|
27
|
Poirier H, Niot I, Monnot MC, Braissant O, Meunier-Durmort C, Costet P, Pineau T, Wahli W, Willson TM, Besnard P. Differential involvement of peroxisome-proliferator-activated receptors alpha and delta in fibrate and fatty-acid-mediated inductions of the gene encoding liver fatty-acid-binding protein in the liver and the small intestine. Biochem J 2001; 355:481-8. [PMID: 11284737 PMCID: PMC1221761 DOI: 10.1042/0264-6021:3550481] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Liver fatty-acid-binding protein (L-FABP) is a cytoplasmic polypeptide that binds with strong affinity especially to long-chain fatty acids (LCFAs). It is highly expressed in both the liver and small intestine, where it is thought to have an essential role in the control of the cellular fatty acid (FA) flux. Because expression of the gene encoding L-FABP is increased by both fibrate hypolipidaemic drugs and LCFAs, it seems to be under the control of transcription factors, termed peroxisome-proliferator-activated receptors (PPARs), activated by fibrate or FAs. However, the precise molecular mechanism by which these regulations take place remain to be fully substantiated. Using transfection assays, we found that the different PPAR subtypes (alpha, gamma and delta) are able to mediate the up-regulation by FAs of the gene encoding L-FABP in vitro. Through analysis of LCFA- and fibrate-mediated effects on L-FABP mRNA levels in wild-type and PPARalpha-null mice, we have found that PPARalpha in the intestine does not constitute a dominant regulator of L-FABP gene expression, in contrast with what is known in the liver. Only the PPARdelta/alpha agonist GW2433 is able to up-regulate the gene encoding L-FABP in the intestine of PPARalpha-null mice. These findings demonstrate that PPARdelta can act as a fibrate/FA-activated receptor in tissues in which it is highly expressed and that L-FABP is a PPARdelta target gene in the small intestine. We propose that PPARdelta contributes to metabolic adaptation of the small intestine to changes in the lipid content of the diet.
Collapse
MESH Headings
- Animals
- Bezafibrate/pharmacology
- Butyrates/pharmacology
- Carrier Proteins/genetics
- DNA Primers
- Fatty Acid-Binding Protein 7
- Fatty Acid-Binding Proteins
- Gene Expression Regulation/drug effects
- Genes, Reporter
- Hypolipidemic Agents
- Intestine, Small/drug effects
- Intestine, Small/metabolism
- Linoleic Acid/pharmacology
- Liver/drug effects
- Liver/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Molecular Sequence Data
- Neoplasm Proteins
- Nerve Tissue Proteins
- Phenylurea Compounds/pharmacology
- Promoter Regions, Genetic
- RNA, Messenger/genetics
- Receptors, Cytoplasmic and Nuclear/agonists
- Receptors, Cytoplasmic and Nuclear/physiology
- Transcription Factors/agonists
- Transcription Factors/physiology
- Transcription, Genetic/physiology
Collapse
Affiliation(s)
- H Poirier
- Physiologie de la Nutrition, Ecole Nationale Supérieure de Biologie Appliquée à la Nutrition et à l'Alimentation (ENSBANA) FRE 2049 CNRS, 1 Esplanade Erasme, CESG/Université de Bourgogne, F-21000 Dijon, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Braissant O, Henry H, Loup M, Eilers B, Bachmann C. Endogenous synthesis and transport of creatine in the rat brain: an in situ hybridization study. Brain Res Mol Brain Res 2001; 86:193-201. [PMID: 11165387 DOI: 10.1016/s0169-328x(00)00269-2] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Creatine is synthesized from arginine by L-arginine:glycine amidinotransferase (AGAT) and S-adenosyl-L-methionine:N-guanidinoacetate methyltransferase (GAMT) and can be taken up by cells by creatine transporters (CRT). While creatine is mainly synthesized by the liver and the kidney, most of other tissues, including the brain, also express AGAT and GAMT. There is evidence that the permeability of the blood-brain barrier (BBB) for creatine is limited, suggesting that the brain is dependent on its own creatine synthesis. In order to better understand creatine synthesis and transport in the central nervous system (CNS), we studied the regional distribution of cells expressing AGAT, GAMT and the creatine transporter CRT1 in the adult rat brain by non-radioisotopic in situ hybridization. AGAT and GAMT presented an ubiquitous neuronal and glial expression, whereas CRT1 was present in neurons and oligodendrocytes throughout the brain, but not in astrocytes. This indicates that all cells in the CNS can synthesize creatine from arginine. The absence of expression of CRT1 in astrocytes and particularly in those contacting capillary endothelial cells (BBB) reinforces the idea that under normal conditions the creatine used by the brain is synthesized mainly in the CNS. Furthermore, the expression of CRT1 by neurons and oligodendrocytes indicates that creatine trafficking is possible in those brain areas of main creatine consumption.
Collapse
Affiliation(s)
- O Braissant
- Central Clinical Chemistry Laboratory, University Hospital, CH-1011, Lausanne, Switzerland.
| | | | | | | | | |
Collapse
|
29
|
Basu-Modak S, Braissant O, Escher P, Desvergne B, Honegger P, Wahli W. Peroxisome proliferator-activated receptor beta regulates acyl-CoA synthetase 2 in reaggregated rat brain cell cultures. J Biol Chem 1999; 274:35881-8. [PMID: 10585473 DOI: 10.1074/jbc.274.50.35881] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors that regulate the expression of many genes involved in lipid metabolism. The biological roles of PPARalpha and PPARgamma are relatively well understood, but little is known about the function of PPARbeta. To address this question, and because PPARbeta is expressed to a high level in the developing brain, we used reaggregated brain cell cultures prepared from dissociated fetal rat telencephalon as experimental model. In these primary cultures, the fetal cells initially form random aggregates, which progressively acquire a tissue-specific pattern resembling that of the brain. PPARs are differentially expressed in these aggregates, with PPARbeta being the prevalent isotype. PPARalpha is present at a very low level, and PPARgamma is absent. Cell type-specific expression analyses revealed that PPARbeta is ubiquitous and most abundant in some neurons, whereas PPARalpha is predominantly astrocytic. We chose acyl-CoA synthetases (ACSs) 1, 2, and 3 as potential target genes of PPARbeta and first analyzed their temporal and cell type-specific pattern. This analysis indicated that ACS2 and PPARbeta mRNAs have overlapping expression patterns, thus designating the ACS2 gene as a putative target of PPARbeta. Using a selective PPARbeta activator, we found that the ACS2 gene is transcriptionally regulated by PPARbeta, demonstrating a role for PPARbeta in brain lipid metabolism.
Collapse
Affiliation(s)
- S Basu-Modak
- Institut de Biologie Animale, Bâtiment de Biologie, Université de Lausanne, CH-1015 Lausanne, Switzerland.
| | | | | | | | | | | |
Collapse
|
30
|
Braissant O, Gotoh T, Loup M, Mori M, Bachmann C. L-arginine uptake, the citrulline-NO cycle and arginase II in the rat brain: an in situ hybridization study. Brain Res Mol Brain Res 1999; 70:231-41. [PMID: 10407171 DOI: 10.1016/s0169-328x(99)00151-5] [Citation(s) in RCA: 100] [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] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Nitric oxide (NO) is synthesized from a unique precursor, arginine, by nitric oxide synthase (NOS). In brain cells, arginine is supplied by protein breakdown or extracted from the blood through cationic amino acid transporters (CATs). Arginine can also be recycled from the citrulline produced by NOS activity, through argininosuccinate synthetase (AS) and argininosuccinate lyase (AL) activities, and metabolized by arginase. NOS, AS and AL constitute the so-called citrulline-NO cycle. In order to better understand arginine transport, recycling and degradation, we studied the regional distribution of cells expressing CAT1, CAT3, AS, AL, neuronal NOS (nNOS) and arginase II (AII) in the adult rat brain by non-radioisotopic in situ hybridization (ISH). CAT1, AL and AII presented an ubiquitous neuronal and glial expression, whereas CAT3 and AS were confined to neurons. nNOS was restricted to scattered neurons and a few brain nuclei and layers. We demonstrate by this study that cells expressing nNOS all appear to express the entire citrulline-NO cycle, whereas numerous cells expressing AL do not express AS. The differential expression of these genes within the same anatomical structure could indicate that intercellular exchanges of citrulline-NO cycle metabolites are relevant. Thus vicinal interactions should be taken into account to study their regulatory mechanisms.
Collapse
Affiliation(s)
- O Braissant
- Central Clinical Chemistry Laboratory, University Hospital, CH-1011, Lausanne, Switzerland.
| | | | | | | | | |
Collapse
|
31
|
Haefliger JA, Waeber B, Grouzmann E, Braissant O, Nussberger J, Nicod P, Waeber G. Cellular localization, expression and regulation of neuropeptide Y in kidneys of hypertensive rats. Regul Pept 1999; 82:35-43. [PMID: 10458644 DOI: 10.1016/s0167-0115(99)00031-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Neuropeptide Y (NPY) is a key modulator of the autonomic nervous system playing pivotal roles in cardiovascular and neuronal functions. In this study, we assessed the cellular localization and gene expression of NPY in rat kidneys. We also examined the relationship between NPY gene expression and renin in two rat models of hypertension (two-kidney, one-clip renal hypertension (2K1C), and deoxycorticosterone-salt-induced hypertension (DOCA-salt)) characterized by a similar blood pressure elevation. In situ hybridization and immunohistochemistry, using anti-NPY or anti-C-flanking peptide of NPY (CPON) antibodies, showed that NPY transcript and protein were colocalized in the tubules of rat kidneys. During experimental hypertension, NPY mRNA was decreased in both kidneys of the 2K1C animals, but not in the kidney of DOCA-salt rats. In 2K1C rats, renal NPY content was also decreased. The difference in NPY gene expression between 2K1C rats (a high renin model of hypertension) and DOCA-salt rats (a low renin model of hypertension) suggests that circulating angiotensin II plays a role in local renal NPY gene expression and that the elevated blood pressure per se is not the primary factor responsible for the control of NPY gene expression in the kidney.
Collapse
Affiliation(s)
- J A Haefliger
- Department of Internal Medicine B, University Hospital, CHUV-1011 Lausanne, Switzerland.
| | | | | | | | | | | | | |
Collapse
|
32
|
Braissant O, Honegger P, Loup M, Iwase K, Takiguchi M, Bachmann C. Hyperammonemia: regulation of argininosuccinate synthetase and argininosuccinate lyase genes in aggregating cell cultures of fetal rat brain. Neurosci Lett 1999; 266:89-92. [PMID: 10353334 DOI: 10.1016/s0304-3940(99)00274-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [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: 10/18/2022]
Abstract
Hyperammonemia in the brain leads to poorly understood alterations of nitric oxide (NO) synthesis. Arginine, the substrate of nitric oxide synthases, might be recycled from the citrulline produced with NO by argininosuccinate synthetase (AS) and argininosuccinate lyase (AL). The regulation of AS and AL genes during hyperammonemia is unknown in the brain. We used brain cell aggregates cultured from dissociated telencephalic cortex of rat embryos to analyze the regulation of AS and AL genes in hyperammonemia. Using RNase protection assay and non-radioactive in situ hybridization on aggregate cryosections, we show that both AS and AL genes are induced in astrocytes but not in neurons of aggregates exposed to 5 mM NH4Cl. Our work suggests that the hyperammonemic brain might increase its recycling of citrulline to arginine.
Collapse
Affiliation(s)
- O Braissant
- Central Clinical Chemistry Laboratory, University Hospital, Lausanne, Switzerland.
| | | | | | | | | | | |
Collapse
|
33
|
Abstract
The expression patterns of the three different peroxisome proliferator-activated receptor (PPAR) isotypes have been determined during rat embryonic development by in situ hybridization. The expression of PPARalpha starts late in development, with increasing levels in organs such as liver, kidney, intestine, and pancreas, in which it will also be present later in adulthood to regulate its specific target genes. PPARalpha is also transiently expressed in the embryonic epidermis and central nervous system. PPARgamma presents a very restricted pattern of expression, being strongly expressed in brown adipose tissue, in which differentiation it has been shown to participate. Like PPARalpha, it is also expressed transiently in the central nervous system. Interestingly, PPARalpha, -beta and -gamma are coexpressed at high levels in brown adipose tissue. Finally, the high and ubiquitous expression of PPARbeta suggests some fundamental role(s) that this receptor might play throughout development.
Collapse
Affiliation(s)
- O Braissant
- Institut de Biologie Animale, Université de Lausanne, Switzerland
| | | |
Collapse
|
34
|
Poirier H, Braissant O, Niot I, Wahli W, Besnard P. 9-cis-retinoic acid enhances fatty acid-induced expression of the liver fatty acid-binding protein gene. FEBS Lett 1997; 412:480-4. [PMID: 9276450 DOI: 10.1016/s0014-5793(97)00830-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [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
The role of retinoic acids (RA) on liver fatty acid-binding protein (L-FABP) expression was investigated in the well differentiated FAO rat hepatoma cell line. 9-cis-Retinoic acid (9-cis-RA) specifically enhanced L-FABP mRNA levels in a time- and dose-dependent manner. The higher induction was found 6 h after addition of 10(-6) M 9-cis-RA in the medium. RA also enhanced further both L-FABP mRNA levels and cytosolic L-FABP protein content induced by oleic acid. The retinoid X receptor (RXR) and the peroxisome proliferator-activated receptor (PPAR), which are known to be activated, respectively, by 9-cis-RA and long chain fatty acid (LCFA), co-operated to bind specifically the peroxisome proliferator-responsive element (PPRE) found upstream of the L-FABP gene. Our result suggest that the PPAR-RXR complex is the molecular target by which 9-cis-RA and LCFA regulate the L-FABP gene.
Collapse
Affiliation(s)
- H Poirier
- Laboratoire de Physiologie de la Nutrition, E.A. DRED 580, Université de Bourgogne, Dijon, France
| | | | | | | | | |
Collapse
|
35
|
Krey G, Braissant O, L'Horset F, Kalkhoven E, Perroud M, Parker MG, Wahli W. Fatty acids, eicosanoids, and hypolipidemic agents identified as ligands of peroxisome proliferator-activated receptors by coactivator-dependent receptor ligand assay. Mol Endocrinol 1997; 11:779-91. [PMID: 9171241 DOI: 10.1210/mend.11.6.0007] [Citation(s) in RCA: 717] [Impact Index Per Article: 26.6] [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
Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors controlling the expression of genes involved in lipid homeostasis. PPARs activate gene transcription in response to a variety of compounds including hypolipidemic drugs as well as natural fatty acids. From the plethora of PPAR activators, Scatchard analysis of receptor-ligand interactions has thus far identified only four ligands. These are the chemotactic agent leukotriene B4 and the hypolipidemic drug Wy 14,643 for the alpha-subtype and a prostaglandin J2 metabolite and synthetic antidiabetic thiazolidinediones for the gamma-subtype. Based on the hypothesis that ligand binding to PPAR would induce interactions of the receptor with transcriptional coactivators, we have developed a novel ligand sensor assay, termed coactivator-dependent receptor ligand assay (CARLA). With CARLA we have screened several natural and synthetic candidate ligands and have identified naturally occurring fatty acids and metabolites as well as hypolipidemic drugs as bona fide ligands of the three PPAR subtypes from Xenopus laevis. Our results suggest that PPARs, by their ability to interact with a number of structurally diverse compounds, have acquired unique ligand-binding properties among the superfamily of nuclear receptors that are compatible with their biological activity.
Collapse
Affiliation(s)
- G Krey
- Institut de Biologie Animale, Bâtiment de Biologie, Université de Lausanne, Switzerland
| | | | | | | | | | | | | |
Collapse
|
36
|
Nuñez SB, Medin JA, Braissant O, Kemp L, Wahli W, Ozato K, Segars JH. Retinoid X receptor and peroxisome proliferator-activated receptor activate an estrogen responsive gene independent of the estrogen receptor. Mol Cell Endocrinol 1997; 127:27-40. [PMID: 9099898 DOI: 10.1016/s0303-7207(96)03980-9] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Estrogen receptors regulate transcription of genes essential for sexual development and reproductive function. Since the retinoid X receptor (RXR) is able to modulate estrogen responsive genes and both 9-cis RA and fatty acids influenced development of estrogen responsive tumors, we hypothesized that estrogen responsive genes might be modulated by RXR and the fatty acid receptor (peroxisome proliferator-activated receptor, PPAR). To test this hypothesis, transfection assays in CV-1 cells were performed with an estrogen response element (ERE) coupled to a luciferase reporter construct. Addition of expression vectors for RXR and PPAR resulted in an 11-fold increase in luciferase activity in the presence of 9-cis RA. Furthermore, mobility shift assays demonstrated binding of RXR and PPAR to the vitellogenin A2-ERE and an ERE in the oxytocin promoter. Methylation interference assays demonstrated that specific guanine residues required for RXR/PPAR binding to the ERE were similar to residues required for ER binding. Moreover, RXR domain-deleted constructs in transfection assays showed that activation required RXR since an RXR delta AF-2 mutant completely abrogated reporter activity. Oligoprecipitation binding studies with biotinylated ERE and (35)S-labeled in vitro translated RXR constructs confirmed binding of delta AF-2 RXR mutant to the ERE in the presence of baculovirus-expressed PPAR. Finally, in situ hybridization confirmed RXR and PPAR mRNA expression in estrogen responsive tissues. Collectively, these data suggest that RXR and PPAR are present in reproductive tissues, are capable of activating estrogen responsive genes and suggest that the mechanism of activation may involve direct binding of the receptors to estrogen response elements.
Collapse
Affiliation(s)
- S B Nuñez
- Unit on the Molecular Mechanisms of Reproduction, Developmental Endocrinology Branch, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | | | | | | | | |
Collapse
|
37
|
Lemberger T, Braissant O, Juge-Aubry C, Keller H, Saladin R, Staels B, Auwerx J, Burger AG, Meier CA, Wahli W. PPAR tissue distribution and interactions with other hormone-signaling pathways. Ann N Y Acad Sci 1996; 804:231-51. [PMID: 8993547 DOI: 10.1111/j.1749-6632.1996.tb18619.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
MESH Headings
- Amino Acid Sequence
- Animals
- Gene Expression Regulation, Enzymologic
- In Situ Hybridization
- Macromolecular Substances
- Mifepristone/pharmacology
- Molecular Sequence Data
- RNA, Messenger/genetics
- Rats
- Rats, Sprague-Dawley
- Receptors, Cytoplasmic and Nuclear/chemistry
- Receptors, Cytoplasmic and Nuclear/physiology
- Receptors, Estrogen/physiology
- Receptors, Glucocorticoid/physiology
- Receptors, Retinoic Acid/chemistry
- Receptors, Retinoic Acid/physiology
- Receptors, Thyroid Hormone/physiology
- Regulatory Sequences, Nucleic Acid
- Retinoid X Receptors
- Sequence Alignment
- Tissue Distribution
- Transcription Factors/chemistry
- Transcription Factors/physiology
Collapse
Affiliation(s)
- T Lemberger
- Institut de Biologié Animale, Université de Lausanne, Switzerland
| | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Braissant O, Foufelle F, Scotto C, Dauça M, Wahli W. Differential expression of peroxisome proliferator-activated receptors (PPARs): tissue distribution of PPAR-alpha, -beta, and -gamma in the adult rat. Endocrinology 1996; 137:354-66. [PMID: 8536636 DOI: 10.1210/endo.137.1.8536636] [Citation(s) in RCA: 1304] [Impact Index Per Article: 46.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily that can be activated by various xenobiotics and natural fatty acids. These transcription factors primarily regulate genes involved in lipid metabolism and also play a role in adipocyte differentiation. We present the expression patterns of the PPAR subtypes in the adult rat, determined by in situ hybridization using specific probes for PPAR-alpha, -beta and -gamma, and by immunohistochemistry using a polyclonal antibody that recognizes the three rat PPAR subtypes. In numerous cell types from either ectodermal, mesodermal, or endodermal origin, PPARs are coexpressed, with relative levels varying between them from one cell type to the other. PPAR-alpha is highly expressed in hepatocytes, cardiomyocytes, enterocytes, and the proximal tubule cells of kidney. PPAR-beta is expressed ubiquitously and often at higher levels than PPAR-alpha and -gamma. PPAR-gamma is expressed predominantly in adipose tissue and the immune system. Our results suggest new potential directions to investigate the functions of the different PPAR subtypes.
Collapse
Affiliation(s)
- O Braissant
- Institut de Biologie Animale, Bâtiment de Biologie, Université de Lausanne, Switzerland
| | | | | | | | | |
Collapse
|
39
|
Wahli W, Braissant O, Desvergne B. Peroxisome proliferator activated receptors: transcriptional regulators of adipogenesis, lipid metabolism and more.... Chem Biol 1995; 2:261-6. [PMID: 9383428 DOI: 10.1016/1074-5521(95)90045-4] [Citation(s) in RCA: 208] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The recent discovery of lipid-activatable transcription factors that regulate the genes controlling lipid metabolism and adipogenesis has provided insight into the way that organisms sense and respond to lipid levels. Identification of the signaling pathways in which these receptors are involved will help us to understand the control of energy balance and the molecular defects underlying its disorders.
Collapse
Affiliation(s)
- W Wahli
- Glaxo Institute for Molecular Biology, Geneva, Switzerland
| | | | | |
Collapse
|
40
|
Affiliation(s)
- M C Lebeau
- Institut de Biologie Animale, Université de Lausanne, Lausanne-Dorigny, Switzerland
| | | | | | | | | |
Collapse
|