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Delay of EGF-Stimulated EGFR Degradation in Myotonic Dystrophy Type 1 (DM1). Cells 2022; 11:cells11193018. [PMID: 36230978 PMCID: PMC9562898 DOI: 10.3390/cells11193018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 09/02/2022] [Accepted: 09/22/2022] [Indexed: 11/18/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is an autosomal dominant disease caused by a CTG repeat expansion in the 3′ untranslated region of the dystrophia myotonica protein kinase gene. AKT dephosphorylation and autophagy are associated with DM1. Autophagy has been widely studied in DM1, although the endocytic pathway has not. AKT has a critical role in endocytosis, and its phosphorylation is mediated by the activation of tyrosine kinase receptors, such as epidermal growth factor receptor (EGFR). EGF-activated EGFR triggers the internalization and degradation of ligand–receptor complexes that serve as a PI3K/AKT signaling platform. Here, we used primary fibroblasts from healthy subjects and DM1 patients. DM1-derived fibroblasts showed increased autophagy flux, with enlarged endosomes and lysosomes. Thereafter, cells were stimulated with a high concentration of EGF to promote EGFR internalization and degradation. Interestingly, EGF binding to EGFR was reduced in DM1 cells and EGFR internalization was also slowed during the early steps of endocytosis. However, EGF-activated EGFR enhanced AKT and ERK1/2 phosphorylation levels in the DM1-derived fibroblasts. Therefore, there was a delay in EGF-stimulated EGFR endocytosis in DM1 cells; this alteration might be due to the decrease in the binding of EGF to EGFR, and not to a decrease in AKT phosphorylation.
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Uribe-Carretero E, Martinez-Chacón G, Yakhine-Diop SMS, Duque-González G, Rodríguez-Arribas M, Alegre-Cortés E, Paredes-Barquero M, Canales-Cortés S, Pizarro-Estrella E, Cuadrado A, González-Polo RA, Fuentes JM, Niso-Santano M. Loss of KEAP1 Causes an Accumulation of Nondegradative Organelles. Antioxidants (Basel) 2022; 11:antiox11071398. [PMID: 35883891 PMCID: PMC9311848 DOI: 10.3390/antiox11071398] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/14/2022] [Accepted: 07/15/2022] [Indexed: 01/04/2023] Open
Abstract
KEAP1 is a cytoplasmic protein that functions as an adaptor for the Cullin-3-based ubiquitin E3 ligase system, which regulates the degradation of many proteins, including NFE2L2/NRF2 and p62/SQSTM1. Loss of KEAP1 leads to an accumulation of protein ubiquitin aggregates and defective autophagy. To better understand the role of KEAP1 in the degradation machinery, we investigated whether Keap1 deficiency affects the endosome-lysosomal pathway. We used KEAP1-deficient mouse embryonic fibroblasts (MEFs) and combined Western blot analysis and fluorescence microscopy with fluorometric and pulse chase assays to analyze the levels of lysosomal-endosomal proteins, lysosomal function, and autophagy activity. We found that the loss of keap1 downregulated the protein levels and activity of the cathepsin D enzyme. Moreover, KEAP1 deficiency caused lysosomal alterations accompanied by an accumulation of autophagosomes. Our study demonstrates that KEAP1 deficiency increases nondegradative lysosomes and identifies a new role for KEAP1 in lysosomal function that may have therapeutic implications.
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Affiliation(s)
- Elisabet Uribe-Carretero
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (E.U.-C.); (G.M.-C.); (G.D.-G.); (M.R.-A.); (E.A.-C.); (M.P.-B.); (S.C.-C.); (E.P.-E.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain; (S.M.S.Y.-D.); (A.C.)
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - Guadalupe Martinez-Chacón
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (E.U.-C.); (G.M.-C.); (G.D.-G.); (M.R.-A.); (E.A.-C.); (M.P.-B.); (S.C.-C.); (E.P.-E.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain; (S.M.S.Y.-D.); (A.C.)
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - Sokhna M. S. Yakhine-Diop
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain; (S.M.S.Y.-D.); (A.C.)
| | - Gema Duque-González
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (E.U.-C.); (G.M.-C.); (G.D.-G.); (M.R.-A.); (E.A.-C.); (M.P.-B.); (S.C.-C.); (E.P.-E.)
| | - Mario Rodríguez-Arribas
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (E.U.-C.); (G.M.-C.); (G.D.-G.); (M.R.-A.); (E.A.-C.); (M.P.-B.); (S.C.-C.); (E.P.-E.)
| | - Eva Alegre-Cortés
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (E.U.-C.); (G.M.-C.); (G.D.-G.); (M.R.-A.); (E.A.-C.); (M.P.-B.); (S.C.-C.); (E.P.-E.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain; (S.M.S.Y.-D.); (A.C.)
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - Marta Paredes-Barquero
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (E.U.-C.); (G.M.-C.); (G.D.-G.); (M.R.-A.); (E.A.-C.); (M.P.-B.); (S.C.-C.); (E.P.-E.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain; (S.M.S.Y.-D.); (A.C.)
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - Saray Canales-Cortés
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (E.U.-C.); (G.M.-C.); (G.D.-G.); (M.R.-A.); (E.A.-C.); (M.P.-B.); (S.C.-C.); (E.P.-E.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain; (S.M.S.Y.-D.); (A.C.)
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - Elisa Pizarro-Estrella
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (E.U.-C.); (G.M.-C.); (G.D.-G.); (M.R.-A.); (E.A.-C.); (M.P.-B.); (S.C.-C.); (E.P.-E.)
| | - Antonio Cuadrado
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain; (S.M.S.Y.-D.); (A.C.)
- Departamento de Bioquímica, Faculdad de Medicina, Universidad Autónoma de Madrid (UAM), 28049 Madrid, Spain
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), 28029 Madrid, Spain
- Instituto de Investigación Sanitaria La Paz (IdiPaz), 28029 Madrid, Spain
| | - Rosa Ana González-Polo
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (E.U.-C.); (G.M.-C.); (G.D.-G.); (M.R.-A.); (E.A.-C.); (M.P.-B.); (S.C.-C.); (E.P.-E.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain; (S.M.S.Y.-D.); (A.C.)
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
- Correspondence: (R.A.G.-P.); (J.M.F.); (M.N.-S.)
| | - José M. Fuentes
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (E.U.-C.); (G.M.-C.); (G.D.-G.); (M.R.-A.); (E.A.-C.); (M.P.-B.); (S.C.-C.); (E.P.-E.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain; (S.M.S.Y.-D.); (A.C.)
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
- Correspondence: (R.A.G.-P.); (J.M.F.); (M.N.-S.)
| | - Mireia Niso-Santano
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (E.U.-C.); (G.M.-C.); (G.D.-G.); (M.R.-A.); (E.A.-C.); (M.P.-B.); (S.C.-C.); (E.P.-E.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 28029 Madrid, Spain; (S.M.S.Y.-D.); (A.C.)
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
- Correspondence: (R.A.G.-P.); (J.M.F.); (M.N.-S.)
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Western Blotting of Membrane-Bound Proteins in Yarrowia lipolytica. Methods Mol Biol 2021. [PMID: 33847994 DOI: 10.1007/978-1-0716-1414-3_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
With the discovery of Western blotting as first described by Towbin et al. in 1979, the transfer and visualization of electrophoretically separated proteins on membranes has become the de facto method for the qualitative and quantitative detection of proteins of interest. In this method, proteins are resolved by electrophoresis on a polyacrylamide gel, followed by a transfer of the separated proteins onto a nitrocellulose or polyvinyl difluoride (PVDF) membrane. Once immobilized on these membranes, the protein of interest can be detected and visualized by exploiting antigen-antibody interactions. However, not all proteins are amenable to easy detection by Western blotting. Integral membrane proteins are a class of proteins that are attached to a biological membrane through a series of transmembrane segments that span the width of the membrane. Due to the inherent hydrophobicity of these proteins and their tendency to aggregate, the characterization and detection of these proteins can be challenging. In this methods chapter, we present a protocol for the easy detection and quantification of these proteins in the industrially important oleaginous yeast Yarrowia lipolytica. The first protocol describes a Western blotting procedure to quantify soluble cytosolic proteins of interest in Yarrowia lipolytica from its total cell lysate. The second protocol describes modifications to the first that are done to enhance detection and quantification of membrane-bound proteins in Yarrowia lipolytica from its total cell lysate, without the need for isolating the membrane-bound proteins, for use in Western blotting. The immunoblotting strategies described here should serve as an efficient and simple guide to quantify both cytosolic and the intractable membrane-bound proteins in Yarrowia lipolytica.
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Lin S, Lv Y, Zheng L, Mao G, Peng F. Expression and Prognosis of Sperm-Associated Antigen 1 in Human Breast Cancer. Onco Targets Ther 2021; 14:2689-2698. [PMID: 33888993 PMCID: PMC8057799 DOI: 10.2147/ott.s288484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 03/17/2021] [Indexed: 12/03/2022] Open
Abstract
Background Sperm-associated antigen 1 (SPAG1) has been identified as a marker of pancreatic cancer progression and promoter of cell motility; however, its role in breast cancer is not completely understood. Methods SPAG1 expression in breast cancer tissues and normal tissues was obtained from online databases. Knockdown function assays were designed and conducted to verify the functional role of SPAG1 in breast cancer cell lines. Cell counting and MTT assays were used to assess cell proliferation. Cell flow cytometry assay was used for cell cycle phase arrest, and fluorescence microscopy was used for colony formation assessment. Results Both the mRNA and protein levels of SPAG1 were significantly higher in the breast cancer tissues than in the normal tissues. In addition, SPAG1 is significantly related to many clinicopathological features of breast cancer, such as age (>51 years), estrogen receptor (ER) (+), progesterone receptor (PR) (+), and nodal status (+), non-triple negative breast cancer (TNBC), not basal-like and not basal-like and not TNBC. Survival analysis indicates that breast cancer patients with low expression of SPAG1 had a significantly better prognosis with relapse-free survival (RFS). Functional experiment analysis revealed that knockdown of SPAG1 suppressed cell proliferation and colony-forming ability. Conclusion Our results suggested a possible role of SPAG1 in breast cancer pathogenesis.
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Affiliation(s)
- Shuangyan Lin
- Department of Pathology, Zhejiang Hospital, Hangzhou, Zhejiang, People's Republic of China
| | - Yanbo Lv
- Department of Pathology, Zhejiang Hospital, Hangzhou, Zhejiang, People's Republic of China
| | - Luoning Zheng
- Department of Pathology, Zhejiang Hospital, Hangzhou, Zhejiang, People's Republic of China
| | - Genxiang Mao
- Department of Geriatrics, Zhejiang Provincial Key Laboratory of Geriatrics, Hangzhou, Zhejiang, People's Republic of China
| | - Fang Peng
- Department of Pathology, Zhejiang Hospital, Hangzhou, Zhejiang, People's Republic of China
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Lin SY, Lv YB, Mao GX, Chen XJ, Peng F. The effect of centromere protein U silencing by lentiviral mediated RNA interference on the proliferation and apoptosis of breast cancer. Oncol Lett 2018; 16:6721-6728. [PMID: 30405814 DOI: 10.3892/ol.2018.9477] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 08/14/2018] [Indexed: 12/18/2022] Open
Abstract
Centromere protein U (CENPU) is a novel transcriptional repressor that is associated with different types of cancer. However, its function in breast cancer is poorly understood. In the present study, it was identified that CENPU was highly expressed in breast cancer tissues compared with expression in normal breast tissues (P=0.001). Furthermore, the CENPU mRNA level in tumors was often elevated, compared with the matched adjacent normal breast cancer tissue specimens in the dataset from The Cancer Genome Atlas database (n=106; P<0.001). To understand the function of CENPU in human breast carcinogenesis, its effects on the proliferation, apoptosis and cell cycle progression of MDA-MB-231 cells were examined using the lentiviral-mediated CENPU knockdown approach. The RNA and protein expression levels in the transfected cells were monitored using reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. The mRNA and protein expression levels of the CENPU gene were significantly lower in the CENPU-shRNA transfected cells than in the control (P<0.01), indicating successful gene expression knockdown. Post-transfection, cell counting and MTT analysis revealed that the proliferation activity was significantly suppressed in CENPU knockdown cells relative to the control (P<0.01). Additionally, fluorescence activated cell sorting analysis revealed that the (G2+S) phase fraction was significantly declined in CENPU knockdown cells relative to the control; while the G1 phase fraction was significantly increased (P<0.01) and the percentage of the apoptotic cells was significantly increased (P<0.01). In conclusion, downregulation of CENPU gene expression may inhibit cell proliferation and cell cycle progression, and increase the apoptosis of the breast cancer cells. These results suggested a possible function of this protein in breast cancer pathogenesis and prognosis.
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Affiliation(s)
- Shuang-Yan Lin
- Department of Pathology, Zhejiang Hospital, Hangzhou, Zhejiang 310013, P.R. China
| | - Yan-Bo Lv
- Department of Pathology, Zhejiang Hospital, Hangzhou, Zhejiang 310013, P.R. China
| | - Gen-Xiang Mao
- Department of Geriatrics, Zhejiang Provincial Key Lab of Geriatrics, Zhejiang Hospital, Hangzhou, Zhejiang 310013, P.R. China
| | - Xu-Jiao Chen
- Department of Geriatrics, Zhejiang Hospital, Hangzhou, Zhejiang 310013, P.R. China
| | - Fang Peng
- Department of Pathology, Zhejiang Hospital, Hangzhou, Zhejiang 310013, P.R. China
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Gómez-Sánchez R, Yakhine-Diop SMS, Rodríguez-Arribas M, Bravo-San Pedro JM, Martínez-Chacón G, Uribe-Carretero E, Pinheiro de Castro DCJ, Pizarro-Estrella E, Fuentes JM, González-Polo RA. mRNA and protein dataset of autophagy markers (LC3 and p62) in several cell lines. Data Brief 2016; 7:641-7. [PMID: 27054171 PMCID: PMC4802425 DOI: 10.1016/j.dib.2016.02.085] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 02/23/2016] [Accepted: 02/29/2016] [Indexed: 11/28/2022] Open
Abstract
We characterized the dynamics of autophagy in vitro using four different cell systems and analyzing markers widely used in this field, i.e. LC3 (microtubule-associated protein 1 light chain 3; protein recruited from the cytosol (LC3-I) to the autophagosomal membrane where it is lipidated (LC3-II)) and p62/SQSTM1 (adaptor protein that serves as a link between LC3 and ubiquitinated substrates), (Klionsky et al., 2016) [1]. Data provided include analyses of protein levels of LC3 and p62 by Western-blotting and endogenous immunofluorescence experiments, but also p62 mRNA levels obtained by quantitative PCR (qPCR). To monitor the turnover of these autophagy markers and, thus, measure the flux of this pathway, cells were under starvation conditions and/or treated with bafilomycin A1 (Baf. A1) to block fusion of autophagosomes with lysosomes.
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Key Words
- Autophagy
- Baf. A1, Bafilomycin A1
- EBSS, Earle׳s Balanced Salt Solution
- FBS, Fetal bovine serum
- GAPDH, Glyceraldehyde 3-phosphate dehydrogenase
- HFs, Human fibroblasts
- LC3
- LC3, Microtubule-associated protein 1 light chain 3
- MEFs, Mouse embryonic fibroblasts
- PBS, Phosphate-buffered saline
- SB, Sample buffer
- SDS, Sodium dodecyl sulfate
- TBST, Tris-buffered saline with Tween 20
- Western-blot
- p62
- qPCR, Quantitative PCR
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Affiliation(s)
- Rubén Gómez-Sánchez
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Spain; Department of Cell Biology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Sokhna M S Yakhine-Diop
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Spain; Departamento de Bioquímica, Biología Molecular y Genética. Facultad de Enfermería y Terapia Ocupacional. Avda de la Universidad S/N C.P, 10003 Cáceres, Spain
| | - Mario Rodríguez-Arribas
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Spain; Departamento de Bioquímica, Biología Molecular y Genética. Facultad de Enfermería y Terapia Ocupacional. Avda de la Universidad S/N C.P, 10003 Cáceres, Spain
| | - José M Bravo-San Pedro
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Spain; Equipe 11 labellisée Ligue contre le Cancer, Centre de Recherche des Cordeliers, 75006 Paris, France; INSERM U1138, 75006 Paris, France; Université Paris Descartes/Paris V, Sorbonne Paris Cité, 75006 Paris, France; Université Pierre et Marie Curie/Paris VI, 75006 Paris, France; Gustave Roussy Comprehensive Cancer Institute, 94805 Villejuif, France
| | - Guadalupe Martínez-Chacón
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Spain; Departamento de Bioquímica, Biología Molecular y Genética. Facultad de Enfermería y Terapia Ocupacional. Avda de la Universidad S/N C.P, 10003 Cáceres, Spain
| | - Elisabet Uribe-Carretero
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Spain; Departamento de Bioquímica, Biología Molecular y Genética. Facultad de Enfermería y Terapia Ocupacional. Avda de la Universidad S/N C.P, 10003 Cáceres, Spain
| | - Diana C J Pinheiro de Castro
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Spain; Departamento de Bioquímica, Biología Molecular y Genética. Facultad de Enfermería y Terapia Ocupacional. Avda de la Universidad S/N C.P, 10003 Cáceres, Spain
| | - Elisa Pizarro-Estrella
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Spain; Departamento de Bioquímica, Biología Molecular y Genética. Facultad de Enfermería y Terapia Ocupacional. Avda de la Universidad S/N C.P, 10003 Cáceres, Spain
| | - José M Fuentes
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Spain; Departamento de Bioquímica, Biología Molecular y Genética. Facultad de Enfermería y Terapia Ocupacional. Avda de la Universidad S/N C.P, 10003 Cáceres, Spain
| | - Rosa A González-Polo
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Spain; Departamento de Bioquímica, Biología Molecular y Genética. Facultad de Enfermería y Terapia Ocupacional. Avda de la Universidad S/N C.P, 10003 Cáceres, Spain
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Gómez-Sánchez R, Pizarro-Estrella E, Yakhine-Diop SM, Rodríguez-Arribas M, Bravo-San Pedro JM, Fuentes JM, González-Polo RA. Routine Western blot to check autophagic flux: Cautions and recommendations. Anal Biochem 2015; 477:13-20. [DOI: 10.1016/j.ab.2015.02.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 11/25/2022]
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G2019S LRRK2 mutant fibroblasts from Parkinson's disease patients show increased sensitivity to neurotoxin 1-methyl-4-phenylpyridinium dependent of autophagy. Toxicology 2014; 324:1-9. [PMID: 25017139 DOI: 10.1016/j.tox.2014.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 07/08/2014] [Accepted: 07/09/2014] [Indexed: 11/23/2022]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder of unknown etiology. It is considered as a multifactorial disease dependent on environmental and genetic factors. Deregulation in cell degradation has been related with a significant increase in cell damage, becoming a target for studies on the PD etiology. In the present study, we have characterized the parkinsonian toxin 1-methyl-4-phenylpyridinium ion (MPP(+))-induced damage in fibroblasts from Parkinson's patients with the mutation G2019S in leucine-rich repeat kinase 2 protein (LRRK2) and control individuals without this mutation. The results reveal that MPP(+) induces mTOR-dependent autophagy in fibroblasts. Moreover, the effects of caspase-dependent cell death to MPP(+) were higher in cells with the G2019S LRRK2 mutation, which showed basal levels of autophagy due to the G2019S LRRK2 mutation (mTOR-independent). The inhibition of autophagy by 3-methyladenine (3-MA) treatment reduces these sensitivity differences between both cell types, however, the inhibition of autophagosome-lysosome fusion by bafilomycin A1 (Baf A1) increases these differences. This data confirm the importance of the combination of genetic and environmental factors in the PD etiology. Thereby, the sensitivity to the same damage may be different in function of a genetic predisposition, reason why individuals with certain mutations can develop some early-onset diseases, such as individuals with G2019S LRRK2 mutation and PD.
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Gómez-Sánchez R, Gegg ME, Bravo-San Pedro JM, Niso-Santano M, Alvarez-Erviti L, Pizarro-Estrella E, Gutiérrez-Martín Y, Alvarez-Barrientos A, Fuentes JM, González-Polo RA, Schapira AHV. Mitochondrial impairment increases FL-PINK1 levels by calcium-dependent gene expression. Neurobiol Dis 2013; 62:426-40. [PMID: 24184327 PMCID: PMC3898697 DOI: 10.1016/j.nbd.2013.10.021] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 10/06/2013] [Accepted: 10/22/2013] [Indexed: 01/02/2023] Open
Abstract
Mutations of the PTEN-induced kinase 1 (PINK1) gene are a cause of autosomal recessive Parkinson's disease (PD). This gene encodes a mitochondrial serine/threonine kinase, which is partly localized to mitochondria, and has been shown to play a role in protecting neuronal cells from oxidative stress and cell death, perhaps related to its role in mitochondrial dynamics and mitophagy. In this study, we report that increased mitochondrial PINK1 levels observed in human neuroblastoma SH-SY5Y cells after carbonyl cyanide m-chlorophelyhydrazone (CCCP) treatment were due to de novo protein synthesis, and not just increased stabilization of full length PINK1 (FL-PINK1). PINK1 mRNA levels were significantly increased by 4-fold after 24h. FL-PINK1 protein levels at this time point were significantly higher than vehicle-treated, or cells treated with CCCP for 3h, despite mitochondrial content being decreased by 29%. We have also shown that CCCP dissipated the mitochondrial membrane potential (Δψm) and induced entry of extracellular calcium through L/N-type calcium channels. The calcium chelating agent BAPTA-AM impaired the CCCP-induced PINK1 mRNA and protein expression. Furthermore, CCCP treatment activated the transcription factor c-Fos in a calcium-dependent manner. These data indicate that PINK1 expression is significantly increased upon CCCP-induced mitophagy in a calcium-dependent manner. This increase in expression continues after peak Parkin mitochondrial translocation, suggesting a role for PINK1 in mitophagy that is downstream of ubiquitination of mitochondrial substrates. This sensitivity to intracellular calcium levels supports the hypothesis that PINK1 may also play a role in cellular calcium homeostasis and neuroprotection.
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Affiliation(s)
- Rubén Gómez-Sánchez
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Departamento de Bioquímica y Biología Molecular y Genética, Universidad de Extremadura, F. Enfermería y Terapia Ocupacional, 10003 Cáceres, Spain
| | - Matthew E Gegg
- Department of Clinical Neurosciences, Institute of Neurology, University College London, London NW3 2PF, UK
| | - José M Bravo-San Pedro
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Departamento de Bioquímica y Biología Molecular y Genética, Universidad de Extremadura, F. Enfermería y Terapia Ocupacional, 10003 Cáceres, Spain; INSERM, U848, Institut Gustave Roussy, Université Paris Sud, Paris 11, F-94805 Villejuif, France
| | - Mireia Niso-Santano
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Departamento de Bioquímica y Biología Molecular y Genética, Universidad de Extremadura, F. Enfermería y Terapia Ocupacional, 10003 Cáceres, Spain; INSERM, U848, Institut Gustave Roussy, Université Paris Sud, Paris 11, F-94805 Villejuif, France
| | - Lydia Alvarez-Erviti
- Department of Clinical Neurosciences, Institute of Neurology, University College London, London NW3 2PF, UK
| | - Elisa Pizarro-Estrella
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Departamento de Bioquímica y Biología Molecular y Genética, Universidad de Extremadura, F. Enfermería y Terapia Ocupacional, 10003 Cáceres, Spain
| | - Yolanda Gutiérrez-Martín
- Servicio de Técnicas Aplicadas a las Biociencias, Universidad de Extremadura, 06071 Badajoz, Spain
| | | | - José M Fuentes
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Departamento de Bioquímica y Biología Molecular y Genética, Universidad de Extremadura, F. Enfermería y Terapia Ocupacional, 10003 Cáceres, Spain.
| | - Rosa Ana González-Polo
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Departamento de Bioquímica y Biología Molecular y Genética, Universidad de Extremadura, F. Enfermería y Terapia Ocupacional, 10003 Cáceres, Spain.
| | - Anthony H V Schapira
- Department of Clinical Neurosciences, Institute of Neurology, University College London, London NW3 2PF, UK
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10
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Bravo-San Pedro JM, Niso-Santano M, Gómez-Sánchez R, Pizarro-Estrella E, Aiastui-Pujana A, Gorostidi A, Climent V, López de Maturana R, Sanchez-Pernaute R, López de Munain A, Fuentes JM, González-Polo RA. The LRRK2 G2019S mutant exacerbates basal autophagy through activation of the MEK/ERK pathway. Cell Mol Life Sci 2013; 70:121-36. [PMID: 22773119 PMCID: PMC11113213 DOI: 10.1007/s00018-012-1061-y] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 05/29/2012] [Accepted: 06/14/2012] [Indexed: 01/16/2023]
Abstract
Mutations in leucine-rich repeat kinase 2 (LRRK2) are a major cause of familial Parkinsonism, and the G2019S mutation of LRRK2 is one of the most prevalent mutations. The deregulation of autophagic processes in nerve cells is thought to be a possible cause of Parkinson's disease (PD). In this study, we observed that G2019S mutant fibroblasts exhibited higher autophagic activity levels than control fibroblasts. Elevated levels of autophagic activity can trigger cell death, and in our study, G2019S mutant cells exhibited increased apoptosis hallmarks compared to control cells. LRRK2 is able to induce the phosphorylation of MAPK/ERK kinases (MEK). The use of 1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene (U0126), a highly selective inhibitor of MEK1/2, reduced the enhanced autophagy and sensibility observed in G2019S LRRK2 mutation cells. These data suggest that the G2019S mutation induces autophagy via MEK/ERK pathway and that the inhibition of this exacerbated autophagy reduces the sensitivity observed in G2019S mutant cells.
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Affiliation(s)
- José M. Bravo-San Pedro
- Departamento de Bioquímica y Biología Molecular y Genética, E. Enfermería y T.O., Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda Universidad, s/n, 10003 Cáceres, Spain
| | - Mireia Niso-Santano
- Departamento de Bioquímica y Biología Molecular y Genética, E. Enfermería y T.O., Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda Universidad, s/n, 10003 Cáceres, Spain
| | - Rubén Gómez-Sánchez
- Departamento de Bioquímica y Biología Molecular y Genética, E. Enfermería y T.O., Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda Universidad, s/n, 10003 Cáceres, Spain
| | - Elisa Pizarro-Estrella
- Departamento de Bioquímica y Biología Molecular y Genética, E. Enfermería y T.O., Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda Universidad, s/n, 10003 Cáceres, Spain
| | - Ana Aiastui-Pujana
- Neuroscience Area, Instituto Biodonostia and CIBERNED, 20014 San Sebastián, Spain
| | - Ana Gorostidi
- Neuroscience Area, Instituto Biodonostia and CIBERNED, 20014 San Sebastián, Spain
| | - Vicente Climent
- Departamento de Anatomía y Embriología Humana, Facultad de Medicina, Universidad de Extremadura, 06071 Badajoz, Spain
| | - Rakel López de Maturana
- Laboratorio de Células madre y Neurorreparación, Fundación Inbiomed, 20009 San Sebastián, Spain
| | | | - Adolfo López de Munain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto Biodonostia, Servicio de Neurología, Hospital Donostia, 20014 San Sebastián, Spain
| | - José M. Fuentes
- Departamento de Bioquímica y Biología Molecular y Genética, E. Enfermería y T.O., Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda Universidad, s/n, 10003 Cáceres, Spain
| | - Rosa A. González-Polo
- Departamento de Bioquímica y Biología Molecular y Genética, E. Enfermería y T.O., Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda Universidad, s/n, 10003 Cáceres, Spain
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11
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Vidau C, González-Polo RA, Niso-Santano M, Gómez-Sánchez R, Bravo-San Pedro JM, Pizarro-Estrella E, Blasco R, Brunet JL, Belzunces LP, Fuentes JM. Fipronil is a powerful uncoupler of oxidative phosphorylation that triggers apoptosis in human neuronal cell line SHSY5Y. Neurotoxicology 2011; 32:935-43. [PMID: 21621551 DOI: 10.1016/j.neuro.2011.04.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2011] [Revised: 03/04/2011] [Accepted: 04/20/2011] [Indexed: 11/28/2022]
Abstract
Fipronil is a phenylpyrazole insecticide known to elicit neurotoxicity via an interaction with ionotropic receptors, namely GABA and glutamate receptors. Recently, we showed that fipronil and other phenylpyrazole compounds trigger cell death in Caco-2 cells. In this study, we investigated the mode of action and the type of cell death induced by fipronil in SH-SY5Y human neuroblastoma cells. Flow cytometric and western blot analyses demonstrated that fipronil induces cellular events belonging to the apoptosis process, such as mitochondrial potential collapse, cytochrome c release, caspase-3 activation, nuclear condensation and phosphatidylserine externalization. In addition, fipronil induces a rapid ATP depletion with concomitant activation of anaerobic glycolysis. This cellular response is characteristic of mitochondrial injury associated with a defect of the respiration process. Therefore, we also investigated the effect of fipronil on the oxygen consumption in isolated mitochondria. Interestingly, we show for the first time that fipronil is a strong uncoupler of oxidative phosphorylation at relative low concentrations. Thus in this study, we report a new mode of action by which the insecticide fipronil could triggers apoptosis.
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Affiliation(s)
- Cyril Vidau
- INRA, Laboratoire de toxicologie environnementale, UMR 406, Abeille et environnement, 84914 Avignon Cedex 9, France
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12
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ASK1 Overexpression Accelerates Paraquat-Induced Autophagy via Endoplasmic Reticulum Stress. Toxicol Sci 2010; 119:156-68. [DOI: 10.1093/toxsci/kfq313] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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13
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Ortiz-Ortiz MA, Morán JM, Ruiz-Mesa LM, Bravo-San Pedro JM, Fuentes JM. Paraquat exposure induces nuclear translocation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the activation of the nitric oxide-GAPDH-Siah cell death cascade. Toxicol Sci 2010; 116:614-22. [PMID: 20478973 DOI: 10.1093/toxsci/kfq146] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Paraquat (PQ) is a well-known herbicide that exerts its effects by elevating intracellular levels of superoxide. It has been previously demonstrated that oxidative and nitrosative stress participate to PQ-induced cell death. Here, we document that PQ increases the levels of nitric oxide (NO) in rat mesencephalic cells and causes nuclear translocation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) to activate the NO/GAPDH/Siah cell death cascade. PQ exposure increases expression of the p300/CREB-binding protein (p300/CBP) and phosphorylation of p53 at Ser 15, which stimulates p53-dependent transactivation through increased binding with p300. Although this cascade could be inhibited by preincubation with the monoamine oxidase B inhibitor deprenyl, cell death was not prevented. Pretreatment of cells with the neuronal nitric oxide synthase inhibitor 7-nitroindazole efficiently prevented the activation of the GAPDH/NO/Siah cell death cascade, thereby protecting cells against PQ-induced toxicity. The results suggest that PQ induces this novel cell death cascade in rat mesencephalic cells, but inhibition of the pathway does not impede cell death because of an oxidative burst generated by the pesticide.
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Affiliation(s)
- Miguel A Ortiz-Ortiz
- Departamento de Bioquímica y Biología Molecular y Genética, EU Enfermería y Terapia Ocupacional, Universidad de Extremadura, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Cáceres, Spain
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14
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Heterologous expression and affinity purification of eukaryotic membrane proteins in view of functional and structural studies: The example of the sarcoplasmic reticulum Ca(2+)-ATPase. Methods Mol Biol 2010; 601:247-67. [PMID: 20099150 DOI: 10.1007/978-1-60761-344-2_15] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Heterologous SERCA1a Ca(2+)-ATPase (sarco-endoplasmic reticulum Ca(2+)-adenosine triphosphatase isoform 1a) from rabbit was expressed in yeast Saccharomyces cerevisiae as a fusion protein, with a biotin acceptor domain (BAD) linked to the SERCA C-terminus by a thrombin cleavage site. Thanks to the pYeDP60 vector, the recombinant protein was expressed under the control of a galactose-inducible promoter. Biotinylation of the protein occurred directly in yeast. Optimizing the number of galactose induction steps and increasing the amount of Gal4p transcription factor both improved expression. Lowering the temperature from 28 to 18 degrees C during expression enhanced the recovery of detergent-extractible active protein. In the "light membrane fraction," thought to mainly contain internal membranes, we are able to recover about 14-18 mg Ca(2+)-ATPase per liter of yeast culture in a bioreactor. Solubilization of this membrane fraction by n-dodecyl beta-D: -maltopyranoside (DDM) allowed us to recover the largest amount of active protein. The in vivo biotinylated recombinant protein was then bound to a streptavidin-Sepharose resin. Selective elution of the biotinylated SERCA1a was carried out after thrombin action on the resin-bound protein. We were able to obtain 200-500 microg/L of yeast culture of a 50% pure SERCA1a that displays an ATPase activity similar to that of the native rabbit Ca(2+)-ATPase. To succeed in crystallization, an additional size exclusion chromatography step was necessary. This step increases purity to 70%, removes aggregated protein and exchanges DDM for C(12)E(8).
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15
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Ortiz-Ortiz MA, Morán JM, Bravosanpedro JM, González-Polo RA, Niso-Santano M, Anantharam V, Kanthasamy AG, Soler G, Fuentes JM. Curcumin enhances paraquat-induced apoptosis of N27 mesencephalic cells via the generation of reactive oxygen species. Neurotoxicology 2009; 30:1008-18. [PMID: 19660496 DOI: 10.1016/j.neuro.2009.07.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 07/22/2009] [Accepted: 07/24/2009] [Indexed: 12/24/2022]
Abstract
Curcumin, the active compound of the rhizome of Curcuma longa has anti-inflammatory, antioxidant and antiproliferative activities. This agent has been shown to regulate numerous transcription factors, cytokines, protein kinases, adhesion molecules, redox status and enzymes that have been linked to inflammation. While curcumin has been identified as an activator of apoptosis in several cell lines, the mechanism by which it initiates apoptosis, however, remains poorly understood. We considered curcumin from the point of view of its ability to protect against oxidative stress, the latter being one factor strongly implicated in the development of Parkinson's disease. Although the etiology of Parkinson's disease remains unknown, epidemiological studies have linked exposure to pesticides such paraquat to an increased risk of developing the condition. Analysis of the neurotoxic properties of these pesticide compounds has been focused on their ability to induce oxidative stress in neural cells. Given curcumin's capacity to protect against oxidative stress, it has been considered as a potential therapeutic agent for neurodegenerative diseases such as Parkinson's disease that involve an oxidative stress component. In the present report we describe the effect of curcumin in paraquat-mediated apoptosis of N27 mesencepahlic cells. We show that subtoxic concentrations of curcumin sensitize N27 mesencephalic cells to paraquat-mediated apoptosis.
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Affiliation(s)
- Miguel A Ortiz-Ortiz
- CIBER de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Bioquímica y Biología Molecular y Genética, EU Enfermería y TO, Universidad de Extremadura, Avda Universidad s/n, 10071 Cáceres, Spain
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16
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Nitric Oxide-Mediated Toxicity in Paraquat-Exposed SH-SY5Y Cells: A Protective Role of 7-Nitroindazole. Neurotox Res 2009; 16:160-73. [DOI: 10.1007/s12640-009-9065-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 04/06/2009] [Accepted: 05/09/2009] [Indexed: 10/20/2022]
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17
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González-Polo RA, Niso-Santano M, Morán JM, Ortiz-Ortiz MA, Bravo-San Pedro JM, Soler G, Fuentes JM. Silencing DJ-1 reveals its contribution in paraquat-induced autophagy. J Neurochem 2009; 109:889-98. [DOI: 10.1111/j.1471-4159.2009.06020.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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18
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Fitzpatrick JM, Fuentes JM, Chalmers IW, Wynn TA, Modolell M, Hoffmann KF, Hesse M. Schistosoma mansoni arginase shares functional similarities with human orthologs but depends upon disulphide bridges for enzymatic activity. Int J Parasitol 2009; 39:267-79. [PMID: 18723022 PMCID: PMC2756234 DOI: 10.1016/j.ijpara.2008.06.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Revised: 06/11/2008] [Accepted: 06/13/2008] [Indexed: 11/19/2022]
Abstract
Schistosome helminths constitute a major health risk for the human population in many tropical areas. We demonstrate for the first time that several developmental stages of the human parasite Schistosoma mansoni express arginase, which is responsible for the hydrolysis of l-arginine to l-ornithine and urea. Arginase activity by alternatively activated macrophages is an essential component of the mammalian host response in schistosomiasis. However, it has not been previously shown that the parasite also expresses arginase when it is in contact with the mammalian host. After cloning and sequencing the cDNA encoding the parasite enzyme, we found that many structural features of human arginase are well conserved in the parasite ortholog. Subsequently, we discovered that S. mansoni arginase shares many similar molecular, biochemical and functional properties with both human arginase isoforms. Nevertheless, our data also reveal striking differences between human and schistosome arginase. Particularly, we found evidence that schistosome arginase activity depends upon disulphide bonds by cysteines, in contrast to human arginase. In conclusion, we report that S. mansoni arginase is well adapted to the physiological conditions that exist in the human host.
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19
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Kaur J, Bachhawat AK. A modified Western blot protocol for enhanced sensitivity in the detection of a membrane protein. Anal Biochem 2009; 384:348-9. [DOI: 10.1016/j.ab.2008.10.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 09/15/2008] [Accepted: 10/07/2008] [Indexed: 11/25/2022]
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20
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Dinis-Oliveira RJ, Sousa C, Remião F, Duarte JA, Ferreira R, Sánchez Navarro A, Bastos ML, Carvalho F. Sodium salicylate prevents paraquat-induced apoptosis in the rat lung. Free Radic Biol Med 2007; 43:48-61. [PMID: 17561093 DOI: 10.1016/j.freeradbiomed.2007.03.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 03/11/2007] [Accepted: 03/13/2007] [Indexed: 11/24/2022]
Abstract
The nonselective contact herbicide, paraquat (PQ), is a strong pneumotoxicant, especially due to its accumulation in the lung through a polyamine uptake system and to its capacity to induce redox cycling, leading to oxidative stress-related damage. In the present study, we aimed to investigate the occurrence of apoptotic events in the lungs of male Wistar rats, 24, 48, and 96 h after PQ exposure (25 mg/kg ip) as well as the putative healing effects provided by sodium salicylate [(NaSAL), 200 mg/kg ip] when administered 2 h after PQ. PQ exposure resulted in marked lung apoptosis, in a time-dependent manner, characterized by the "ladder-like" pattern of DNA observed through electrophoresis and by the presence of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL)-positive cells (TPC) as revealed by immunohistochemistry. The two main caspase cascades (the extrinsic receptor-mediated and the intrinsic mitochondria-mediated) and the expressions of p53 and activator protein-1 (AP-1) were also evaluated, to obtain an insight into apoptotic cellular signaling. PQ-exposed rats suffered a time-dependent increase of caspase-3 and caspase-8 and a decrease of caspase-1 activities in lungs compared to the control group. A marked mitochondrial dysfunction evidenced by cytochrome c (Cyt c) release was also observed as a consequence of PQ exposure. In addition, fluorescence electrophoretic mobility shift assay (fEMSA) revealed a transcriptional induction of the p53 and AP-1 transcription factors in a time-dependent manner as a consequence of PQ exposure. NaSAL treatment resulted in the remission of the observed apoptotic signaling and consequently of lung apoptosis. Taken together, the present results showed that PQ activates several events involved in the apoptotic pathways, which might contribute to its lung toxicodynamics. NaSAL, a recently implemented antidote for PQ intoxications, proved to protect lungs from PQ-induced apoptosis.
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Affiliation(s)
- R J Dinis-Oliveira
- REQUIMTE, Departamento de Toxicologia, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4099-030 Porto, Portugal.
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21
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Kropf P, Baud D, Marshall SE, Munder M, Mosley A, Fuentes JM, Bangham CRM, Taylor GP, Herath S, Choi BS, Soler G, Teoh T, Modolell M, Müller I. Arginase activity mediates reversible T cell hyporesponsiveness in human pregnancy. Eur J Immunol 2007; 37:935-45. [PMID: 17330821 PMCID: PMC2699382 DOI: 10.1002/eji.200636542] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 11/15/2006] [Accepted: 02/01/2007] [Indexed: 11/24/2022]
Abstract
Complex regulation of T cell functions during pregnancy is required to ensure materno-fetal tolerance. Here we reveal a novel pathway for the temporary suppression of maternal T cell responses in uncomplicated human pregnancies. Our results show that arginase activity is significantly increased in the peripheral blood of pregnant women and remarkably high arginase activities are expressed in term placentae. High enzymatic activity results in high turnover of its substrate L-arginine and concomitant reduction of this amino acid in the microenvironment. Amino acid deprivation is emerging as a regulatory pathway of lymphocyte responses and we assessed the consequences of this enhanced arginase activity on T cell responses. Arginase-mediated L-arginine depletion induces down-regulation of CD3 zeta, the main signalling chain of the TCR, and functional T cell hyporesponsiveness. Importantly, this arginase-mediated T cell suppression was reversible, as inhibition of arginase activity or addition of exogenous L-arginine restored CD3 zeta chain expression and T cell proliferation. Thus, L-arginine metabolism constitutes a novel physiological mechanism contributing to the temporary suppression of the maternal immune response during human pregnancy.
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Affiliation(s)
- Pascale Kropf
- Department of Immunology, Faculty of Medicine, Imperial College LondonLondon, UK
| | - David Baud
- Department of Obstetrics and Gynaecology, St. Mary's HospitalLondon, UK
| | - Sara E Marshall
- Department of Immunology, Faculty of Medicine, Imperial College LondonLondon, UK
| | - Markus Munder
- Department of Hematology, Oncology, and Rheumatology, University Hospital HeidelbergHeidelberg, Germany
| | - Angelina Mosley
- Department of Immunology, Faculty of Medicine, Imperial College LondonLondon, UK
| | - José M Fuentes
- Departamento de Bioquímica y Biología Molecular, E.U. Enfermería y T.O., Universidad de ExtremaduraCáceres, Spain
| | - Charles R M Bangham
- Department of Immunology, Faculty of Medicine, Imperial College LondonLondon, UK
| | - Graham P Taylor
- Department of Genito-Urinary Medicine and Communicable Diseases, Imperial CollegeLondon, UK
| | - Shanti Herath
- Department of Veterinary Clinical Sciences, Royal Veterinary CollegeLondon, UK
| | - Beak-San Choi
- Department of Immunology, Faculty of Medicine, Imperial College LondonLondon, UK
| | - Germán Soler
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad de ExtremaduraCáceres, Spain
| | - Tg Teoh
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad de ExtremaduraCáceres, Spain
| | - Manuel Modolell
- Department of Cellular Immunology, Max-Planck-Institute for ImmunobiologyFreiburg, Germany
| | - Ingrid Müller
- Department of Immunology, Faculty of Medicine, Imperial College LondonLondon, UK
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22
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Niso-Santano M, Morán JM, García-Rubio L, Gómez-Martín A, González-Polo RA, Soler G, Fuentes JM. Low concentrations of paraquat induces early activation of extracellular signal-regulated kinase 1/2, protein kinase B, and c-Jun N-terminal kinase 1/2 pathways: role of c-Jun N-terminal kinase in paraquat-induced cell death. Toxicol Sci 2006; 92:507-15. [PMID: 16687388 DOI: 10.1093/toxsci/kfl013] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Paraquat is a herbicide with a potential risk to induce parkinsonism due to its demonstrated neurotoxicity and its strong structural similarity to 1-methyl-4-phenylpyridinium (MPP(+)), a well-known neurotoxin which causes a clinical syndrome similar to Parkinson's disease (PD). However, at present very little is known about the signaling pathways activated by paraquat in any cell system. In this study, we have investigated the effect of paraquat on extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun N-terminal kinase (JNK), and protein kinase B (PKB) activation in E18 cells. Low concentrations of paraquat stimulated very early increases in ERK1/2, JNK1/2, and PKB phosphorylation. The phosphatidylinositol 3-kinase (PI-3K) inhibitors wortmannin and LY 294002 (2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one) inhibited early paraquat-induced increases in PKB phosphorylation. Furthermore, early paraquat-mediated increases in ERK1/2 activation were sensitive to the mitogen-activated protein kinase kinase 1 (MEK1) inhibitor PD 98059 (2'-amino-3'-methoxyflavone), whereas JNK1/2 responses were blocked by the JNK1/2 inhibitor SP 600125 (anthra[1-9-cd]pyrazol-6(2H)-one). Pretreatment with wortmannin, LY 294002, or PD 98059 had no effect on paraquat cell death in E18 cells. In contrast, SP 600125 significantly decreased paraquat-induced cell death in E18 cells. In conclusion, we have shown that low concentrations of paraquat stimulate robust very early increases in ERK1/2, JNK1/2, and PKB phosphorylation in E18 cells. Furthermore, the data presented clearly suggest that inhibition of the JNK1/2 pathway protects E18 cells from paraquat-induced cell death and support the fact that inhibition of early activation of JNK1/2 can constitute a potential strategy in PD treatment.
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Affiliation(s)
- Mireia Niso-Santano
- Departamento de Bioquímica y Biología Molecular y Genética, E.U. Enfermería y T.O., Universidad de Extremadura, Avda. de la Universidad s/n 10071 Cáceres, Spain
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23
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Jidenko M, Lenoir G, Fuentes JM, le Maire M, Jaxel C. Expression in yeast and purification of a membrane protein, SERCA1a, using a biotinylated acceptor domain. Protein Expr Purif 2006; 48:32-42. [PMID: 16603381 DOI: 10.1016/j.pep.2006.03.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2005] [Revised: 02/24/2006] [Accepted: 03/01/2006] [Indexed: 11/19/2022]
Abstract
We have recently described the final steps leading to the crystallization of a mammalian membrane protein, the rabbit sarcoplasmic reticulum Ca2+-ATPase, after heterologous expression. Here, we detail the initial steps leading to this new purification method. A biotin acceptor domain was fused at the C-terminal part of Ca2+-ATPase and a thrombin site was inserted between both coding regions. The recombinant protein was expressed under the control of a galactose-inducible promoter in the yeast Saccharomyces cerevisiae. The biotinylation reaction of the protein was performed directly in vivo in yeast. After solubilization of the yeast light membrane fraction, the biotinylated protein was retained specifically using the strong biotin-avidin interaction. Finally, digestion by the protease thrombin allowed the separation of the Ca2+-ATPase from the biotinylated domain. At this step, Ca2+-ATPase is in a relatively purified form (about 40%). After a size-exclusion HPLC step, the purity of the protein is about 70%, and evaluation of the conformational changes during the catalytic cycle by monitoring the intrinsic fluorescence is demonstrated. The major advantage of this avidin procedure is the particularly good specific ATPase activity as compared with that of a purified His-tagged Ca2+-ATPase.
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Affiliation(s)
- Marie Jidenko
- Unité de Recherche Associée 2096 of the Centre National de la Recherche Scientifique and Service de Biophysique des Fonctions Membranaires, Département de Biologie Joliot Curie, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
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24
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Donaire V, Niso M, Morán JM, García L, González-Polo RA, Soler G, Fuentes JM. Heat shock proteins protect both MPP+ and paraquat neurotoxicity. Brain Res Bull 2005; 67:509-14. [PMID: 16216701 DOI: 10.1016/j.brainresbull.2005.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Revised: 07/27/2005] [Accepted: 08/08/2005] [Indexed: 10/25/2022]
Abstract
The exposure of immortalized rat neuroblast cells to MPP(+) and paraquat results in cell death. Heat shock pre-treatment prior to the addition of MPP(+) and paraquat significantly reduced cell death and led to an increase in the synthesis of Hsp 27 and Hsp70 proteins. Quercetin inhibits the synthesis of heat shock proteins (Hsp) and prevents their protective effect, which suggests that this protection was dependent on the Hsps synthesis. These data indicate that heat shock protects cells from the toxic effect of MPP(+) and paraquat. These results and the structural similarity between paraquat and MPP(+) support the role of paraquat as a putative risk factor in the etiology of Parkinson's disease.
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Affiliation(s)
- Vanessa Donaire
- Universidad de Extremadura, Departamento de Bioquímica y Biología Molecular y Genética, E.U. Enfermería y T.O., Avda. de la Universidad s/n, 10071 Caceres, Spain
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25
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Kropf P, Fuentes JM, Fähnrich E, Arpa L, Herath S, Weber V, Soler G, Celada A, Modolell M, Müller I. Arginase and polyamine synthesis are key factors in the regulation of experimental leishmaniasis in vivo. FASEB J 2005; 19:1000-2. [PMID: 15811879 DOI: 10.1096/fj.04-3416fje] [Citation(s) in RCA: 219] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Arginase 1, an enzyme induced by Th2 cytokines, is a hallmark of alternatively activated macrophages and is responsible for the hydrolysis of L-arginine into ornithine, the building block for the production of polyamines. Upregulation of arginase 1 has been observed in a variety of diseases, but the mechanisms by which arginase contributes to pathology are not well understood. We reveal here a unique role for arginase 1 in the pathogenesis of nonhealing leishmaniasis, a prototype Th2 disease, and demonstrate that the activity of this enzyme promotes pathology and uncontrolled growth of Leishmania parasites in vivo. Inhibition of arginase activity during the course of infection has a clear therapeutic effect, as evidenced by markedly reduced pathology and efficient control of parasite replication. Despite the clear amelioration of the disease, this treatment does not alter the Th2 response. To address the underlying mechanisms, the arginase-induced L-arginine catabolism was investigated and the results demonstrate that arginase regulates parasite growth directly by affecting the polyamine synthesis in macrophages.
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Affiliation(s)
- Pascale Kropf
- Department of Immunology, Faculty of Medicine, Imperial College London, UK
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26
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González-Polo RA, Rodríguez-Martín A, Morán JM, Niso M, Soler G, Fuentes JM. Paraquat-induced apoptotic cell death in cerebellar granule cells. Brain Res 2004; 1011:170-6. [PMID: 15157803 DOI: 10.1016/j.brainres.2004.02.078] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2004] [Indexed: 11/21/2022]
Abstract
We examined the toxicity of paraquat, a possible environmental risk factor for neurodegenerative disorders like Parkinson's disease (PD). Paraquat is structurally similar to the neurotoxin MPP+ that can induce Parkinsonian-like features in rodents, non-human primates and human. Exposure of cerebellar granule cells to relatively low concentrations of paraquat (5 microM) produces apoptotic cell death with a reduction in mitochondrial cytochrome c content, proteolytic activation and caspase-3 activity increase and DNA fragmentation. Paraquat-induced apoptosis was significantly attenuated by co-treatment of cerebellar granule cells with the radical scavenger vitamin E, suggesting that paraquat-induced free radicals serve as important signal in initiation of cell death. As a decrease in mitochondrial cytochrome c content is also prevented by allopurinol, we suggest that xanthine oxidase plays an important role in the free radical production that precedes the apoptotic cascade and cell death after paraquat exposition.
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Affiliation(s)
- Rosa A González-Polo
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Veterinaria, Universidad de Extremadura, Cáceres, Spain
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27
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González-Polo RA, Soler G, Alvarez A, Fabregat I, Fuentes JM. Vitamin E blocks early events induced by 1-methyl-4-phenylpyridinium (MPP+) in cerebellar granule cells. J Neurochem 2003; 84:305-15. [PMID: 12558993 DOI: 10.1046/j.1471-4159.2003.01520.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Exposure of cerebellar granule cells (CGCs) to 1-methyl-4-phenylpyridinium (MPP+) results in apoptotic cell death, which is markedly attenuated by co-treatment of CGCs with the radical scavenger vitamin E. Analysis of free radical production and mitochondrial transmembrane potential (DeltaPsim), using specific fluorescent probes, showed that MPP+ mediates early radical oxygen species (ROS) production without a loss of DeltaPsim. Exposure to MPP+ also produces an early increase in Bad dephosphorylation and translocation of Bax to the mitochondria. These events are accompanied by cytochrome c release from mitochondria to cytosol, which is followed by caspase 3 activation. Exposure of the neurons to vitamin E maintains Bad phosphorylation and attenuates Bax translocation, inhibiting cytochrome c release and caspase activation. MPP+-mediated cytochrome c release is also prevented by allopurinol, suggesting the participation of xanthine oxidase in the process. Our results indicate that free radicals play an active role in the MPP+-induced early events that culminate with cell death.
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Affiliation(s)
- Rosa A González-Polo
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Veterinaria, Universidad de Extremadura, Cáceres, Spain
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28
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Sarramegna V, Talmont F, Seree de Roch M, Milon A, Demange P. Green fluorescent protein as a reporter of human mu-opioid receptor overexpression and localization in the methylotrophic yeast Pichia pastoris. J Biotechnol 2002; 99:23-39. [PMID: 12204555 DOI: 10.1016/s0168-1656(02)00161-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The human mu-opioid receptor (HuMOR) was fused in its N-terminus end to the green fluorescent protein (GFP) or/and to the c-myc and six histidines tags in its C-terminus end, and expressed in the methylotrophic yeast Pichia pastoris. Neither the C- nor the N-terminal tagging of the receptor does modify its pharmacological properties as compared to the untagged receptor. Expression levels of fusion receptors determined by GFP fluorescence measurements strongly correlates with the number of sites expressed per cell detected through saturation studies (Bmax value), thus showing that GFP is an efficient and reliable reporter of the HuMOR functional expression. The N- and C-terminus tags have allowed to show that the entire molecule is overexpressed. They have permitted in-situ localization experiments using fluorescence and electron microscopy techniques and have shown a dense intracellular labelling. Above all, the quantification of expression levels made possible through fluorescence intensity analysis, have revealed that huge amounts of receptor are produced that could not be detected through classical binding experiments: for a Bmax value of 1 pmol mg(-1) of receptor determined through binding studies, 16 pmol were found in membrane preparations using fluorescence and 100 pmol in whole cells. These results should be very useful for large-scale production and structural biology of HuMOR, and other G-protein coupled receptors (GPCRs).
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Affiliation(s)
- Valérie Sarramegna
- Institut de Pharmacologie et de Biologie Structurale, UMR 5089, Centre National de la Recherche Scientifique, Université Paul Sabatier, 205 route de Narbonne, 31077 Toulouse Cedex 4, France.
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29
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Hadri L, Ozog A, Soncin F, Lompré AM. Basal transcription of the mouse sarco(endo)plasmic reticulum Ca2+-ATPase type 3 gene in endothelial cells is controlled by Ets-1 and Sp1. J Biol Chem 2002; 277:36471-8. [PMID: 12119294 DOI: 10.1074/jbc.m204731200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We reported previously that the sarco(endo)plasmic reticulum Ca(2+)-ATPase type 3 (SERCA3) gene is expressed in many tissues and in a subset of cells such as endothelial, epithelial, and lymphoid lineages. Here we analyzed the mechanisms involved in the regulation of transcription of the SERCA3 gene in endothelial cells. The promoter of the murine SERCA3 gene was isolated, and a single transcription initiation site located 301 bp upstream of the translation initiation site was identified. Analysis of the transcriptional activity of fragments of the SERCA3 promoter showed the existence of a minimal promoter region located between bases -97 and +153 that contains one ETS-binding site (EBS) and two Sp1 elements that are essential for basal transcription. Mutation of the EBS or of the Sp1 sites abolished the basal activity of the promoter. We identified Ets-1 and Sp1 among endothelial nuclear factors that recognize the EBS and Sp1 sites on the promoter. Furthermore, transactivation of the -97/+301 promoter fragment by Ets-1 requires the presence of both the EBS and Sp1 sites, suggesting an interaction of the transcription factors on the gene promoter. Finally, overexpression of Ets-1 induced the expression of SERCA3 in endothelial cells and in fibroblasts.
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Affiliation(s)
- Lahouaria Hadri
- INSERM U446/Biochimie, IFR-75, Signalisation et Innovation Thérapeutique Tour D4, Faculté de Pharmacie, 92296 Chatenay-Malabry, France
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30
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Kerner J, Turkaly PJ, Minkler PE, Hoppel CL. Aging skeletal muscle mitochondria in the rat: decreased uncoupling protein-3 content. Am J Physiol Endocrinol Metab 2001; 281:E1054-62. [PMID: 11595663 DOI: 10.1152/ajpendo.2001.281.5.e1054] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The goal of the present study was to discern the cellular mechanism(s) that contributes to the age-associated decrease in skeletal muscle aerobic capacity. Skeletal muscle mitochondrial content, a parameter of oxidative capacity, was significantly lower (25 and 20% calculated on the basis of citrate synthase and succinate dehydrogenase activities, respectively) in 24-mo-old Fischer 344 rats compared with 6-mo-old adult rats. Mitochondria isolated from skeletal muscle of both age groups had identical state 3 (ADP-stimulated) and ADP-stimulated maximal respiratory rates and phosphorylation potential (ADP-to-O ratios) with both nonlipid and lipid substrates. In contrast, mitochondria from 24-mo-old rats displayed significantly lower state 4 (ADP-limited) respiratory rates and, consequently, higher respiratory control ratios. Consistent with the tighter coupling, there was a 68% reduction in uncoupling protein-3 (UCP-3) abundance in mitochondria from elderly compared with adult rats. Congruent with the respiratory studies, there was no age-associated decrease in carnitine palmitoyltransferase I and carnitine palmitoyltransferase II activities in isolated skeletal muscle mitochondria. However, there was a small, significant decrease in tissue total carnitine content. It is concluded that the in vivo observed decrease in skeletal muscle aerobic capacity with advanced age is a consequence of the decreased mitochondrial density. On the basis of the dramatic reduction of UCP-3 content associated with decreased state 4 respiration of skeletal muscle mitochondria from elderly rats, we propose that an increased free radical production might contribute to the metabolic compromise in aging.
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Affiliation(s)
- J Kerner
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio 44106, USA.
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31
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Chami M, Gozuacik D, Lagorce D, Brini M, Falson P, Peaucellier G, Pinton P, Lecoeur H, Gougeon ML, le Maire M, Rizzuto R, Bréchot C, Paterlini-Bréchot P. SERCA1 truncated proteins unable to pump calcium reduce the endoplasmic reticulum calcium concentration and induce apoptosis. J Cell Biol 2001; 153:1301-14. [PMID: 11402072 PMCID: PMC2192035 DOI: 10.1083/jcb.153.6.1301] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
By pumping calcium from the cytosol to the ER, sarco/endoplasmic reticulum calcium ATPases (SERCAs) play a major role in the control of calcium signaling. We describe two SERCA1 splice variants (S1Ts) characterized by exon 4 and/or exon 11 splicing, encoding COOH terminally truncated proteins, having only one of the seven calcium-binding residues, and thus unable to pump calcium. As shown by semiquantitative RT-PCR, S1T transcripts are differentially expressed in several adult and fetal human tissues, but not in skeletal muscle and heart. S1T proteins expression was detected by Western blot in nontransfected cell lines. In transiently transfected cells, S1T homodimers were revealed by Western blot using mildly denaturing conditions. S1T proteins were shown, by confocal scanning microscopy, to colocalize with endogenous SERCA2b into the ER membrane. Using ER-targeted aequorin (erAEQ), we have found that S1T proteins reduce ER calcium and reverse elevation of ER calcium loading induced by SERCA1 and SERCA2b. Our results also show that SERCA1 variants increase ER calcium leakage and are consistent with the hypothesis of a cation channel formed by S1T homodimers. Finally, when overexpressed in liver-derived cells, S1T proteins significantly induce apoptosis. These data reveal a further mechanism modulating Ca(2+) accumulation into the ER of nonmuscle cells and highlight the relevance of S1T proteins to the control of apoptosis.
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Affiliation(s)
- Mounia Chami
- The French Institute of Health and Medical Research Institut National de la Santé et de la Recherche Médicale (INSERM/Pasteur U370)/Necker Faculty Institute of Medicine, 75015 Paris, France
| | - Devrim Gozuacik
- The French Institute of Health and Medical Research Institut National de la Santé et de la Recherche Médicale (INSERM/Pasteur U370)/Necker Faculty Institute of Medicine, 75015 Paris, France
| | - David Lagorce
- The French Institute of Health and Medical Research Institut National de la Santé et de la Recherche Médicale (INSERM/Pasteur U370)/Necker Faculty Institute of Medicine, 75015 Paris, France
| | - Marisa Brini
- Department of Biochemistry and Center for the Study of Biomembranes of the National Research Council (CNR), University of Padova, 35121 Padova, Italy
| | - Pierre Falson
- URA Centre National de Recherche Scientifique (CNRS) 2096, CEA Saclay, 91191 Gif sur Yvette, France
| | - Gérard Peaucellier
- National Center Scientific Research, URA 2156, Arago Laboratory, F66651 Banyuls sur mer, France
| | - Paolo Pinton
- Department of Experimental and Diagnostic Medicine, Section of General Pathology, 44100 Ferrara, Italy
| | - Hervé Lecoeur
- Pasteur Institute, Unit of Viral Oncology, SIDA Department of Retrovirus, 75015 Paris, France
| | - Marie-Lyse Gougeon
- Pasteur Institute, Unit of Viral Oncology, SIDA Department of Retrovirus, 75015 Paris, France
| | - Marc le Maire
- URA Centre National de Recherche Scientifique (CNRS) 2096, CEA Saclay, 91191 Gif sur Yvette, France
| | - Rosario Rizzuto
- Department of Experimental and Diagnostic Medicine, Section of General Pathology, 44100 Ferrara, Italy
| | - Christian Bréchot
- The French Institute of Health and Medical Research Institut National de la Santé et de la Recherche Médicale (INSERM/Pasteur U370)/Necker Faculty Institute of Medicine, 75015 Paris, France
| | - Patrizia Paterlini-Bréchot
- The French Institute of Health and Medical Research Institut National de la Santé et de la Recherche Médicale (INSERM/Pasteur U370)/Necker Faculty Institute of Medicine, 75015 Paris, France
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