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Yi SJ, Jang YJ, Lee S, Cho SJ, Kang K, Park JI, Chae HJ, Kim HR, Kim K. TMBIM6 deficiency leads to bone loss by accelerating osteoclastogenesis. Redox Biol 2023; 64:102804. [PMID: 37399733 PMCID: PMC10336580 DOI: 10.1016/j.redox.2023.102804] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 06/15/2023] [Accepted: 06/27/2023] [Indexed: 07/05/2023] Open
Abstract
TMBIM6 is an endoplasmic reticulum (ER) protein that modulates various physiological and pathological processes, including metabolism and cancer. However, its involvement in bone remodeling has not been investigated. In this study, we demonstrate that TMBIM6 serves as a crucial negative regulator of osteoclast differentiation, a process essential for bone remodeling. Our investigation of Tmbim6-knockout mice revealed an osteoporotic phenotype, and knockdown of Tmbim6 inhibited the formation of multinucleated tartrate-resistant acid phosphatase-positive cells, which are characteristic of osteoclasts. Transcriptome and immunoblot analyses uncovered that TMBIM6 exerts its inhibitory effect on osteoclastogenesis by scavenging reactive oxygen species and preventing p65 nuclear localization. Additionally, TMBIM6 depletion was found to promote p65 localization to osteoclast-related gene promoters. Notably, treatment with N-acetyl cysteine, an antioxidant, impeded the osteoclastogenesis induced by TMBIM6-depleted cells, supporting the role of TMBIM6 in redox regulation. Furthermore, we discovered that TMBIM6 controls redox regulation via NRF2 signaling pathways. Our findings establish TMBIM6 as a critical regulator of osteoclastogenesis and suggest its potential as a therapeutic target for the treatment of osteoporosis.
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Affiliation(s)
- Sun-Ju Yi
- Department of Biological Sciences and Biotechnology, Chungbuk National University, Cheongju, Chungbuk, 28644, Republic of Korea
| | - You-Jee Jang
- Department of Biomedical Laboratory Science, Honam University, Gwangju, Republic of Korea
| | - Seokchan Lee
- Department of Biological Sciences and Biotechnology, Chungbuk National University, Cheongju, Chungbuk, 28644, Republic of Korea
| | - Sung-Jin Cho
- Department of Biological Sciences and Biotechnology, Chungbuk National University, Cheongju, Chungbuk, 28644, Republic of Korea
| | - Kyuho Kang
- Department of Biological Sciences and Biotechnology, Chungbuk National University, Cheongju, Chungbuk, 28644, Republic of Korea
| | - Jae-Il Park
- Korea Basic Science Institute, Gwangju Center at Chonnam National University, Gwangju, Republic of Korea
| | - Han-Jung Chae
- School of Pharmacy and New Drug Development Research Institute, Jeonbuk National University, Jeonju, Republic of Korea
| | - Hyung-Ryong Kim
- Department of Pharmacology, College of Dentistry, Jeonbuk National University, Jeonju, Republic of Korea
| | - Kyunghwan Kim
- Department of Biological Sciences and Biotechnology, Chungbuk National University, Cheongju, Chungbuk, 28644, Republic of Korea.
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2
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Han C, Yang J, Zhang E, Jiang Y, Qiao A, Du Y, Zhang Q, An J, Sun J, Wang M, Nguyen T, Lal H, Krishnamurthy P, Zhang J, Qin G. Metabolic labeling of cardiomyocyte-derived small extracellular-vesicle (sEV) miRNAs identifies miR-208a in cardiac regulation of lung gene expression. J Extracell Vesicles 2022; 11:e12246. [PMID: 36250966 PMCID: PMC9575700 DOI: 10.1002/jev2.12246] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 11/06/2022] Open
Abstract
Toxoplasma gondii uracil phosphoribosyltransferase (UPRT) converts 4-thiouracil (4TUc) into 4-thiouridine (4TUd), which is incorporated into nascent RNAs and can be biotinylated, then labelled with streptavidin conjugates or isolated via streptavidin-affinity methods. Here, we generated mice that expressed T. gondii UPRT only in cardiomyocytes (CM UPRT mice) and tested our hypothesis that CM-derived miRNAs (CM miRs) are transferred into remote organs after myocardial infarction (MI) by small extracellular vesicles (sEV) that are released from the heart into the peripheral blood (PB sEV). We found that 4TUd was incorporated with high specificity and sensitivity into RNAs isolated from the hearts and PB sEV of CM UPRT mice 6 h after 4TUc injection. In PB sEV, 4TUd was incorporated into CM-specific/enriched miRs including miR-208a, but not into miRs with other organ or tissue-type specificities. 4TUd-labelled miR208a was also present in lung tissues, especially lung endothelial cells (ECs), and CM-derived miR-208a (CM miR-208a) levels peaked 12 h after experimentally induced MI in PB sEV and 24 h after MI in the lung. Notably, miR-208a is expressed from intron 29 of α myosin heavy chain (αMHC), but αMHC transcripts were nearly undetectable in the lung. When PB sEV from mice that underwent MI (MI-PB sEV) or sham surgery (Sham-PB sEV) were injected into intact mice, the expression of Tmbim6 and NLK, which are suppressed by miR-208a and cooperatively regulate inflammation via the NF-κB pathway, was lower in the lungs of MI-PB sEV-treated animals than the lungs of animals treated with Sham-PB sEV or saline. In MI mice, Tmbim6 and NLK were downregulated, whereas endothelial adhesion molecules and pro-inflammatory cells were upregulated in the lung; these changes were significantly attenuated when the mice were treated with miR-208a antagomirs prior to MI surgery. Thus, CM UPRT mice enables us to track PB sEV-mediated transport of CM miRs and identify an miR-208a-mediated mechanism by which myocardial injury alters the expression of genes and inflammatory response in the lung.
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Affiliation(s)
- Chaoshan Han
- Department of Biomedical EngineeringSchool of Medicine and School of EngineeringUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Junjie Yang
- Department of Biomedical EngineeringSchool of Medicine and School of EngineeringUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Eric Zhang
- Department of Biomedical EngineeringSchool of Medicine and School of EngineeringUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Ying Jiang
- Department of Biomedical EngineeringSchool of Medicine and School of EngineeringUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Aijun Qiao
- Department of Biomedical EngineeringSchool of Medicine and School of EngineeringUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Yipeng Du
- Department of Biomedical EngineeringSchool of Medicine and School of EngineeringUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Qinkun Zhang
- Department of MedicineDivision of Cardiovascular DiseaseSchool of MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Junqing An
- Center for Molecular and Translational MedicineGeorgia State UniversityAtlantaGeorgiaUSA
| | - Jiacheng Sun
- Department of Biomedical EngineeringSchool of Medicine and School of EngineeringUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Meimei Wang
- Department of Biomedical EngineeringSchool of Medicine and School of EngineeringUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Thanh Nguyen
- Department of Biomedical EngineeringSchool of Medicine and School of EngineeringUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Hind Lal
- Department of MedicineDivision of Cardiovascular DiseaseSchool of MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Prasanna Krishnamurthy
- Department of Biomedical EngineeringSchool of Medicine and School of EngineeringUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Jianyi Zhang
- Department of Biomedical EngineeringSchool of Medicine and School of EngineeringUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Gangjian Qin
- Department of Biomedical EngineeringSchool of Medicine and School of EngineeringUniversity of Alabama at BirminghamBirminghamAlabamaUSA
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3
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Deng J, Gutiérrez LG, Stoll G, Motiño O, Martins I, Núñez L, Bravo-San Pedro JM, Humeau J, Bordenave C, Pan J, Fohrer-Ting H, Souquere S, Pierron G, Hetz C, Villalobos C, Kroemer G, Senovilla L. Paradoxical implication of BAX/BAK in the persistence of tetraploid cells. Cell Death Dis 2021; 12:1039. [PMID: 34725331 PMCID: PMC8560871 DOI: 10.1038/s41419-021-04321-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 09/28/2021] [Accepted: 10/06/2021] [Indexed: 12/22/2022]
Abstract
Pro-apoptotic multi-domain proteins of the BCL2 family such as BAX and BAK are well known for their important role in the induction of mitochondrial outer membrane permeabilization (MOMP), which is the rate-limiting step of the intrinsic pathway of apoptosis. Human or mouse cells lacking both BAX and BAK (due to a double knockout, DKO) are notoriously resistant to MOMP and cell death induction. Here we report the surprising finding that BAX/BAK DKO cells proliferate less than control cells expressing both BAX and BAK (or either BAX or BAK) when they are driven into tetraploidy by transient exposure to the microtubule inhibitor nocodazole. Mechanistically, in contrast to their BAX/BAK-sufficient controls, tetraploid DKO cells activate a senescent program, as indicated by the overexpression of several cyclin-dependent kinase inhibitors and the activation of β-galactosidase. Moreover, DKO cells manifest alterations in ionomycin-mobilizable endoplasmic reticulum (ER) Ca2+ stores and store-operated Ca2+ entry that are affected by tetraploidization. DKO cells manifested reduced expression of endogenous sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a (Serca2a) and transfection-enforced reintroduction of Serca2a, or reintroduction of an ER-targeted variant of BAK into DKO cells reestablished the same pattern of Ca2+ fluxes as observed in BAX/BAK-sufficient control cells. Serca2a reexpression and ER-targeted BAK also abolished the tetraploidy-induced senescence of DKO cells, placing ER Ca2+ fluxes downstream of the regulation of senescence by BAX/BAK. In conclusion, it appears that BAX/BAK prevent the induction of a tetraploidization-associated senescence program. Speculatively, this may contribute to the low incidence of cancers in BAX/BAK DKO mice and explain why human cancers rarely lose the expression of both BAX and BAK.
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Affiliation(s)
- Jiayin Deng
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Equipe 11 Labellisée par la Ligue Contre le Cancer, F-75006, Paris, France
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France
| | - Lucía G Gutiérrez
- Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid - CSIC, Valladolid, Spain
| | - Gautier Stoll
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Equipe 11 Labellisée par la Ligue Contre le Cancer, F-75006, Paris, France
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France
| | - Omar Motiño
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Equipe 11 Labellisée par la Ligue Contre le Cancer, F-75006, Paris, France
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France
| | - Isabelle Martins
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Equipe 11 Labellisée par la Ligue Contre le Cancer, F-75006, Paris, France
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France
| | - Lucía Núñez
- Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid - CSIC, Valladolid, Spain
| | - José Manuel Bravo-San Pedro
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Equipe 11 Labellisée par la Ligue Contre le Cancer, F-75006, Paris, France
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France
- Facultad de Medicina, Departamento de Fisiología, Universidad Complutense de Madrid, Madrid, Spain
| | - Juliette Humeau
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Equipe 11 Labellisée par la Ligue Contre le Cancer, F-75006, Paris, France
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montreal, QC, Canada, H3C 3J7
- Department of Medicine, Université de Montréal, Montreal, QC, Canada, H3C 3J7
| | - Chloé Bordenave
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Equipe 11 Labellisée par la Ligue Contre le Cancer, F-75006, Paris, France
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France
| | - Juncheng Pan
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Equipe 11 Labellisée par la Ligue Contre le Cancer, F-75006, Paris, France
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France
| | - Hélène Fohrer-Ting
- Centre de Recherche des Cordeliers, Center for Histology, Cell Imaging and Cytometry (CHIC), Sorbonne Université, Inserm, Université de Paris, F-75006, Paris, France
| | | | - Gerard Pierron
- CNRS, UMR9196, Gustave Roussy Cancer Campus, Villejuif, France
| | - Claudio Hetz
- Faculty of Medicine, Biomedical Neuroscience Institute (BNI), University of Chile, Santiago, 8380453, Chile
- Center for Geroscience, Brain Health and Metabolism (GERO), Santiago, 7800003, Chile
- The Buck Institute for Research in Aging, Novato, CA, 94945, USA
| | - Carlos Villalobos
- Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid - CSIC, Valladolid, Spain.
| | - Guido Kroemer
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Equipe 11 Labellisée par la Ligue Contre le Cancer, F-75006, Paris, France.
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France.
- Pôle de Biologie, Hopitâl Européen George Pompidou, AP-HP, Paris, France.
| | - Laura Senovilla
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Equipe 11 Labellisée par la Ligue Contre le Cancer, F-75006, Paris, France.
- Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, Villejuif, France.
- Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid - CSIC, Valladolid, Spain.
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Zhang L, Buhr S, Voigt A, Methner A. The Evolutionary Conserved Transmembrane BAX Inhibitor Motif (TMBIM) Containing Protein Family Members 5 and 6 Are Essential for the Development and Survival of Drosophila melanogaster. Front Cell Dev Biol 2021; 9:666484. [PMID: 34540824 PMCID: PMC8446389 DOI: 10.3389/fcell.2021.666484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 08/16/2021] [Indexed: 11/30/2022] Open
Abstract
The mammalian Transmembrane BAX Inhibitor Motif (TMBIM) protein family consists of six evolutionarily conserved hydrophobic proteins that affect programmed cell death and the regulation of intracellular calcium levels. The bacterial ortholog BsYetJ is a pH-dependent calcium channel. We here identified seven TMBIM family members in Drosophila melanogaster and describe their expression levels in diverse tissues and developmental stages. A phylogenetic analysis revealed that CG30379 represents the ortholog of human TMBIM4 although these two proteins are much less related than TMBIM5 (CG2076 and CG1287/Mics1) and TMBIM6 (CG7188/Bi-1) to their respective orthologs. For TMBIM1-3 the assignment is more dubious because the fly and the human proteins cluster together. We conducted a functional analysis based on expression levels and the availability of RNAi lines. This revealed that the ubiquitous knockdown of CG3798/Nmda1 and CG3814/Lfg had no effect on development while knockdown of CG2076/dTmbim5 resulted in death at the pupa stage and knockdown of CG7188/dTmbim6 in death at the embryonic stage. Ubiquitous knockdown of the second TMBIM5 paralog CG1287/Mics1 ensued in male sterility. Knockdown of dTmbim5 and 6 in muscle and neural tissue also greatly reduced lifespan through different mechanisms. Knockdown of the mitochondrial family member dTmbim5 resulted in reduced ATP production and a pro-apoptotic expression profile while knockdown of the ER protein dTmbim6 increased the ER calcium levels similar to findings in mammalian cells. Our data demonstrate that dTmbim5 and 6 are essential for fly development and survival but affect cell survival through different mechanisms.
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Affiliation(s)
- Li Zhang
- University Medical Center, Institute for Molecular Medicine, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Sebastian Buhr
- University Medical Center, Institute for Molecular Medicine, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Aaron Voigt
- Department of Neurology, RWTH Aachen University, Aachen, Germany.,Forschungszentrum Jülich GmbH, JARA-Institute Molecular Neuroscience and Neuroimaging, RWTH Aachen University, Aachen, Germany
| | - Axel Methner
- University Medical Center, Institute for Molecular Medicine, Johannes Gutenberg University Mainz, Mainz, Germany
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5
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Chen W, Yang X, Zhou Y, Ma Q, Wu X, Sha Y, Qian G. [Bax inhibitor-1 inhibits calcification of vascular smooth muscle cells in vitro]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2021; 41:1177-1182. [PMID: 34549708 DOI: 10.12122/j.issn.1673-4254.2021.08.08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate the effect of Bax inhibitor-1(BI-1)on calcification of vascular smooth muscle cells(VSMCs). METHODS VSMCs were isolated from the thoracic aorta of SD rats.VSMCs or BI-1-overexpressing VSMCs(transfected with a BI-1-overexpressing plasmid) were cultured in normal medium or calcified medium containing β-glycerophosphate and calcium chloride, and the cell calcification was examined with Alizarin red staining.Enzyme-linked immunosorbent assay was used to determine the intracellular calcium content and alkaline phosphatase activity.The expression levels of Runt-related transcription factor 2 (RUNX2), bone morphogenetic protein 2 (BMP-2) and caspase-3 were detected with Western blotting. RESULTS After 14 days of culture in the calcified medium, the VSMCs showed significantly reduced expression of BI-1 protein(P=0.001).BI-1 overexpression in the VSMCs caused a significant reduction of calcium level and alkaline phosphatase activities(P=0.0006) and lowered the expression levels of RUNX2 and BMP-2 (P=0.0001) in the cells.The VSMCs with induced calcification exhibited a significantly increased apoptosis rate, but BI-1 overexpression obviously inhibited VSMC apoptosis in the calcified medium (P=0.0003). CONCLUSION BI-1 may attenuate vascular calcification by inhibiting calcium deposition, osteogenic differentiation and apoptosis.
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Affiliation(s)
- W Chen
- Department of Cardiology, Beijing Anzhen Hospital of Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Disease, Beijing Key Laboratory of Precision Medicine of Coronary Atherosclerotic Disease, Beijing 100029, China.,Department of Cardiology, Second Medical Center, General Hospital of PLA, Beijing 100853, China
| | - X Yang
- Department of Cardiology, First Medical Center, General Hospital of PLA, Beijing 100853, China
| | - Y Zhou
- Department of Cardiology, Beijing Anzhen Hospital of Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Disease, Beijing Key Laboratory of Precision Medicine of Coronary Atherosclerotic Disease, Beijing 100029, China
| | - Q Ma
- Department of Cardiology, Beijing Anzhen Hospital of Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Disease, Beijing Key Laboratory of Precision Medicine of Coronary Atherosclerotic Disease, Beijing 100029, China
| | - X Wu
- Department of Cardiology, Second Medical Center, General Hospital of PLA, Beijing 100853, China
| | - Y Sha
- Department of Cardiology, Second Medical Center, General Hospital of PLA, Beijing 100853, China
| | - G Qian
- Department of Cardiology, First Medical Center, General Hospital of PLA, Beijing 100853, China
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6
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Lemos FO, Bultynck G, Parys JB. A comprehensive overview of the complex world of the endo- and sarcoplasmic reticulum Ca 2+-leak channels. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119020. [PMID: 33798602 DOI: 10.1016/j.bbamcr.2021.119020] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/09/2021] [Accepted: 03/13/2021] [Indexed: 12/11/2022]
Abstract
Inside cells, the endoplasmic reticulum (ER) forms the largest Ca2+ store. Ca2+ is actively pumped by the SERCA pumps in the ER, where intraluminal Ca2+-binding proteins enable the accumulation of large amount of Ca2+. IP3 receptors and the ryanodine receptors mediate the release of Ca2+ in a controlled way, thereby evoking complex spatio-temporal signals in the cell. The steady state Ca2+ concentration in the ER of about 500 μM results from the balance between SERCA-mediated Ca2+ uptake and the passive leakage of Ca2+. The passive Ca2+ leak from the ER is often ignored, but can play an important physiological role, depending on the cellular context. Moreover, excessive Ca2+ leakage significantly lowers the amount of Ca2+ stored in the ER compared to normal conditions, thereby limiting the possibility to evoke Ca2+ signals and/or causing ER stress, leading to pathological consequences. The so-called Ca2+-leak channels responsible for Ca2+ leakage from the ER are however still not well understood, despite over 20 different proteins have been proposed to contribute to it. This review has the aim to critically evaluate the available evidence about the various channels potentially involved and to draw conclusions about their relative importance.
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Affiliation(s)
- Fernanda O Lemos
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, B-3000 Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, B-3000 Leuven, Belgium
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, B-3000 Leuven, Belgium.
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7
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Drouin A, Wallbillich N, Theberge M, Liu S, Katz J, Bellovoda K, Se Yun Cheon S, Gootkind F, Bierman E, Zavras J, Berberich MJ, Kalocsay M, Guastaldi F, Salvadori N, Troulis M, Fusco DN. Impact of Zika virus on the human type I interferon osteoimmune response. Cytokine 2021; 137:155342. [PMID: 33130337 DOI: 10.1016/j.cyto.2020.155342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 09/25/2020] [Accepted: 10/08/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND The developing field of osteoimmunology supports importance of an interferon (IFN) response pathway in osteoblasts. Clarifying osteoblast-IFN interactions is important because IFN is used as salvage anti-tumor therapy but systemic toxicity is high with variable clinical results. In addition, osteoblast response to systemic bursts and disruptions of IFN pathways induced by viral infection may influence bone remodeling. ZIKA virus (ZIKV) infection impacts bone development in humans and IFN response in vitro. Consistently, initial evidence of permissivity to ZIKV has been reported in human osteoblasts. HYPOTHESIS Osteoblast-like Saos-2 cells are permissive to ZIKV and responsive to IFN. METHODS Multiple approaches were used to assess whether Saos-2 cells are permissive to ZIKV infection and exhibit IFN-mediated ZIKV suppression. Proteomic methods were used to evaluate impact of ZIKV and IFN on Saos-2 cells. RESULTS Evidence is presented confirming Saos-2 cells are permissive to ZIKV and support IFN-mediated suppression of ZIKV. ZIKV and IFN differentially impact the Saos-2 proteome, exemplified by HELZ2 protein which is upregulated by IFN but non responsive to ZIKV. Both ZIKV and IFN suppress proteins associated with microcephaly/pseudo-TORCH syndrome (BI1, KI20A and UBP18), and ZIKV induces potential entry factor PLVAP. CONCLUSIONS Transient ZIKV infection influences osteoimmune state, and IFN and ZIKV activate distinct proteomes in Saos-2 cells, which could inform therapeutic, engineered, disruptions.
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Affiliation(s)
- Arnaud Drouin
- Department of Medicine, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA, 70114, United States; Department of Pathology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA, 70114, United States
| | - Nicholas Wallbillich
- Department of Medicine, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA, 70114, United States
| | - Marc Theberge
- Tulane University, 6823 St Charles Ave, New Orleans, LA 70118, United States
| | - Sharon Liu
- Department of Medicine, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA, 70114, United States
| | - Joshua Katz
- Tulane University, 6823 St Charles Ave, New Orleans, LA 70118, United States
| | - Kamela Bellovoda
- Department of Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, United States
| | - Scarlett Se Yun Cheon
- Department of Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, United States
| | - Frederick Gootkind
- Department of Oral & Maxillofacial Surgery, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114, United States
| | - Emily Bierman
- Department of Oral & Maxillofacial Surgery, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114, United States
| | - Jason Zavras
- Department of Oral & Maxillofacial Surgery, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114, United States
| | - Matthew J Berberich
- Laboratory of Systems Pharmacology, Harvard Medical School, Armenise Building, 200 Longwood, Ave, Boston, MA 02115, United States
| | - Marian Kalocsay
- Laboratory of Systems Pharmacology, Harvard Medical School, Armenise Building, 200 Longwood, Ave, Boston, MA 02115, United States
| | - Fernando Guastaldi
- Department of Oral & Maxillofacial Surgery, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114, United States
| | - Nicolas Salvadori
- Institut de recherche pour le développement (IRD)-PHPT, Marseille, France; Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Maria Troulis
- Department of Oral & Maxillofacial Surgery, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114, United States
| | - Dahlene N Fusco
- Department of Medicine, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA, 70114, United States.
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8
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Philippaert K, Roden M, Lisak D, Bueno D, Jelenik T, Radyushkin K, Schacht T, Mesuere M, Wüllner V, Herrmann AK, Baumgart J, Vennekens R, Methner A. Bax inhibitor-1 deficiency leads to obesity by increasing Ca 2+-dependent insulin secretion. J Mol Med (Berl) 2020; 98:849-862. [PMID: 32394396 PMCID: PMC7297831 DOI: 10.1007/s00109-020-01914-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 04/14/2020] [Accepted: 04/21/2020] [Indexed: 12/28/2022]
Abstract
Abstract Transmembrane BAX inhibitor motif containing 6 (TMBIM6), also known as Bax inhibitor-1, is an evolutionarily conserved protein involved in endoplasmic reticulum (ER) function. TMBIM6 is an ER Ca2+ leak channel and its deficiency enhances susceptibility to ER stress due to inhibition of the ER stress sensor IRE1α. It was previously shown that TMBIM6 overexpression improves glucose metabolism and that TMBIM6 knockout mice develop obesity. We here examined the metabolic alterations underlying the obese phenotype and subjected TMBIM6 knockout mice to indirect calorimetry and euglycemic-hyperinsulinemic tests with stable isotope dilution to gauge tissue-specific insulin sensitivity. This demonstrated no changes in heat production, food intake, activity or hepatic and peripheral insulin sensitivity. TMBIM6 knockout mice, however, featured a higher glucose-stimulated insulin secretion in vivo as assessed by the hyperglycemic clamp test and hepatic steatosis. This coincided with profound changes in glucose-mediated Ca2+ regulation in isolated pancreatic β cells and increased levels of IRE1α levels but no differences in downstream effects of IRE1α like increased Xbp1 mRNA splicing or Ire1-dependent decay of insulin mRNA in the pancreas. We therefore conclude that lack of TMBIM6 does not affect insulin sensitivity but leads to hyperinsulinemia, which serves to explain the weight gain. TMBIM6-mediated metabolic alterations are mainly caused by its role as a Ca2+ release channel in the ER. Key messages TMBIM6−/− leads to obesity and hepatic steatosis. Food intake and energy expenditure are not changed in TMBIM6−/− mice. No changes in insulin resistance in TMBIM6−/− mice. Increased insulin secretion caused by altered calcium dynamics in β cells.
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Affiliation(s)
- Koenraad Philippaert
- Laboratory of Ion Channel Research, VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Michael Roden
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany. .,Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Düsseldorf, Germany. .,German Center for Diabetes Research (DZD), München-Neuherberg, Germany.
| | - Dmitrij Lisak
- Institute for Molecular Medicine of the University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Diones Bueno
- Institute for Molecular Medicine of the University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Tomas Jelenik
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Düsseldorf, Germany.,German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | | | - Teresa Schacht
- Institute for Molecular Medicine of the University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Margot Mesuere
- Laboratory of Ion Channel Research, VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Verena Wüllner
- Institute for Molecular Medicine of the University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Ann-Kathrin Herrmann
- Institute for Molecular Medicine of the University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Jan Baumgart
- Translational Animal Research Center, The Johannes Gutenberg University, Mainz, Germany
| | - Rudi Vennekens
- Laboratory of Ion Channel Research, VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Axel Methner
- Institute for Molecular Medicine of the University Medical Center, Johannes Gutenberg University, Mainz, Germany.
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9
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Kim HK, Lee GH, Bhattarai KR, Lee MS, Back SH, Kim HR, Chae HJ. TMBIM6 (transmembrane BAX inhibitor motif containing 6) enhances autophagy through regulation of lysosomal calcium. Autophagy 2020; 17:761-778. [PMID: 32167007 PMCID: PMC8032251 DOI: 10.1080/15548627.2020.1732161] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Lysosomal Ca2+ contributes to macroautophagy/autophagy, an intracellular process for the degradation of cytoplasmic material and organelles in the lysosomes to protect cells against stress responses. TMBIM6 (transmembrane BAX inhibitor motif containing 6) is a Ca2+ channel-like protein known to regulate ER stress response and apoptosis. In this study, we examined the as yet unknown role of TMBIM6 in regulating lysosomal Ca2+ levels. The Ca2+ efflux from the ER through TMBIM6 was found to increase the resting lysosomal Ca2+ level, in which ITPR-independent regulation of Ca2+ status was observed. Further, TMBIM6 regulated the local release of Ca2+ through lysosomal MCOLN1/TRPML1 channels under nutrient starvation or MTOR inhibition. The local Ca2+ efflux through MCOLN1 channels was found to activate PPP3/calcineurin, triggering TFEB (transcription factor EB) nuclear translocation, autophagy induction, and lysosome biogenesis. Upon genetic inactivation of TMBIM6, lysosomal Ca2+ and the associated TFEB nuclear translocation were decreased. Furthermore, autophagy flux was significantly enhanced in the liver or kidney from starved Tmbim6+/+ mice compared with that in the counter tmbim6-/- mice. Together, our observations indicated that under stress conditions, TMBIM6 increases lysosomal Ca2+ release, leading to PPP3/calcineurin-mediated TFEB activation and subsequently enhanced autophagy. Thus, TMBIM6, an ER membrane protein, is suggested to be a lysosomal Ca2+ modulator that coordinates with autophagy to alleviate metabolism stress.Abbreviations: AVs: autophagic vacuoles; CEPIA: calcium-measuring organelle-entrapped protein indicator; ER: endoplasmic reticulum; GPN: glycyl-L-phenylalanine-beta-naphthylamide; ITPR/IP3R: inositol 1,4,5-trisphosphate receptor; LAMP1: lysosomal associated membrane protein 1; MCOLN/TRPML: mucolipin; MEF: mouse embryonic fibroblast; ML-SA1: mucolipin synthetic agonist 1; MTORC1: mechanistic target of rapamycin kinase complex 1; RPS6KB1: ribosomal protein S6 kinase B1; SQSTM1: sequestosome 1; TFEB: transcription factor EB; TKO: triple knockout; TMBIM6/BI-1: transmembrane BAX inhibitor motif containing 6.
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Affiliation(s)
- Hyun-Kyoung Kim
- Department of Pharmacology and New Drug Development Research Institute, Chonbuk National University Medical School, Jeonju, Republic of Korea
| | - Geum-Hwa Lee
- Department of Pharmacology and New Drug Development Research Institute, Chonbuk National University Medical School, Jeonju, Republic of Korea
| | - Kashi Raj Bhattarai
- Department of Pharmacology and New Drug Development Research Institute, Chonbuk National University Medical School, Jeonju, Republic of Korea
| | - Myung-Shik Lee
- Severance Biomedical Science Institute and Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Sung Hoon Back
- School of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea
| | - Hyung-Ryong Kim
- College of Dentistry, Dankook University, Cheonan, Republic of Korea
| | - Han-Jung Chae
- Department of Pharmacology and New Drug Development Research Institute, Chonbuk National University Medical School, Jeonju, Republic of Korea
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10
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Mohanty S, Barik P, Debata N, Nagarajan P, Devadas S. iCa 2+ Flux, ROS and IL-10 Determines Cytotoxic, and Suppressor T Cell Functions in Chronic Human Viral Infections. Front Immunol 2020; 11:83. [PMID: 32210950 PMCID: PMC7068714 DOI: 10.3389/fimmu.2020.00083] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 01/13/2020] [Indexed: 12/13/2022] Open
Abstract
Exhaustion of CD8+ T cells and increased IL-10 production is well-known in chronic viral infections but mechanisms leading to loss of their cytotoxic capabilities and consequent exhaustion remain unclear. Exhausted CD8+T cells also called T suppressors are highly immune suppressive with altered T cell receptor signaling characteristics that mark it exclusively from their cytotoxic counterparts. Our study found that iCa2+ flux is reduced following T cell receptor activation in T suppressor cells when compared to their effector counterpart. Importantly chronic activation of murine cytotoxic CD8+ T cells lead to reduced iCa2+ influx, decreased IFN-γ and enhanced IL-10 production and this profile is mimicked in Tc1 cells upon reduction of iCa2+ flux by extracellular calcium channel inhibitors. Further reduced iCa2+ flux induced ROS which lead to IFN-γ reduction and increased IL-10 producing T suppressors through the STAT3—STAT5 axis. The above findings were substantiated by our human data where reduced iCa2+ flux in chronic Hepatitis infections displayed CD8+ T cells with low IFN-γ and increased IL-10 production. Importantly treatment with an antioxidant led to increased IFN-γ and reduced IL-10 production in human chronic Hep-B/C samples suggesting overall a proximal regulatory role for iCa2+ influx, ROS, and IL-10 in determining the effector/ suppressive axis of CD8+ T cells.
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Affiliation(s)
- Subhasmita Mohanty
- Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Prakash Barik
- Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
| | - Nagen Debata
- Department of Pathology, Institute of Medical Sciences and SUM Hospital, Bhubaneswar, India
| | - Perumal Nagarajan
- Experimental Animal Facility, National Institute of Immunology, New Delhi, India
| | - Satish Devadas
- Infectious Disease Biology, Institute of Life Sciences, Bhubaneswar, India
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11
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DNA-PKcs promotes cardiac ischemia reperfusion injury through mitigating BI-1-governed mitochondrial homeostasis. Basic Res Cardiol 2020; 115:11. [PMID: 31919590 DOI: 10.1007/s00395-019-0773-7] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 12/27/2019] [Indexed: 01/24/2023]
Abstract
DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a novel inducer to promote mitochondrial apoptosis and suppress tumor growth in a variety of cells although its role in cardiovascular diseases remains obscure. This study was designed to examine the role of DNA-PKcs in cardiac ischemia reperfusion (IR) injury and mitochondrial damage. Cardiomyocyte-specific DNA-PKcs knockout (DNA-PKcsCKO) mice were subjected to IR prior to assessment of myocardial function and mitochondrial apoptosis. Our data revealed that IR challenge, hypoxia-reoxygenation (HR) or H2O2-activated DNA-PKcs through post-transcriptional phosphorylation in murine hearts or cardiomyocytes. Mice deficient in DNA-PKcs in cardiomyocytes were protected against cardiomyocyte death, infarct area expansion and cardiac dysfunction. DNA-PKcs ablation countered IR- or HR-induced oxidative stress, mPTP opening, mitochondrial fission, mitophagy failure and Bax-mediated mitochondrial apoptosis, possibly through suppression of Bax inhibitor-1 (BI-1) activity. A direct association between DNA-PKcs and BI-1 was noted where DNA-PKcs had little effect on BI-1 transcription but interacted with BI-1 to promote its degradation. Loss of DNA-PKcs stabilized BI-1, thus offering resistance of mitochondria and cardiomyocytes against IR insult. Moreover, DNA-PKcs ablation-induced beneficial cardioprotection against IR injury was mitigated by concurrent knockout of BI-1. Double deletion of DNA-PKcs and BI-1 failed to exert protection against global IR injury and mitochondrial damage, confirming a permissive role of BI-1 in DNA-PKcs deletion-elicited cardioprotection against IR injury. DNA-PKcs serves as a novel causative factor for mitochondrial damage via suppression of BI-1, en route to the onset and development of cardiac IR injury.
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12
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Lebeaupin C, Blanc M, Vallée D, Keller H, Bailly-Maitre B. BAX inhibitor-1: between stress and survival. FEBS J 2020; 287:1722-1736. [PMID: 31841271 DOI: 10.1111/febs.15179] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/18/2019] [Accepted: 12/13/2019] [Indexed: 12/13/2022]
Abstract
Cellular gatekeepers are essential to maintain order within a cell and anticipate signals of stress to promote survival. BCL2 associated X, apoptosis regulator (BAX) inhibitor-1 (BI-1), also named transmembrane BAX inhibitor motif containing-6, is a highly conserved endoplasmic reticulum (ER) transmembrane protein. Originally identified as an inhibitor of BAX-induced apoptosis, its pro-survival properties have been expanded to include functions targeted against ER stress, calcium imbalance, reactive oxygen species accumulation, and metabolic dysregulation. Nevertheless, the structural biology and biochemical mechanism of action of BI-1 are still under debate. BI-1 has been implicated in several diseases, including chronic liver disease, diabetes, ischemia/reperfusion injury, neurodegeneration, and cancer. While most studies have demonstrated a beneficial role for BI-1 in the ubiquitous maintenance of cellular homeostasis, its expression in cancer cells seems most often to contribute to tumorigenesis and metastasis. Here, we summarize what is known about BI-1 and encourage future studies on BI-1's contribution to cellular life and death decisions to advocate its potential as a target for drug development and other therapeutic strategies.
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Affiliation(s)
- Cynthia Lebeaupin
- INSERM U1065, C3M, Université Côte d'Azur, Nice, France.,Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.,Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Marina Blanc
- INSERM U1065, C3M, Université Côte d'Azur, Nice, France
| | | | - Harald Keller
- INRA1355-CNRS7254, Université Côte d'Azur, Sophia Antipolis, France
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13
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Molecular Mechanisms of Calcium Signaling During Phagocytosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1246:103-128. [PMID: 32399828 DOI: 10.1007/978-3-030-40406-2_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Calcium (Ca2+) is a ubiquitous second messenger involved in the regulation of numerous cellular functions including vesicular trafficking, cytoskeletal rearrangements and gene transcription. Both global as well as localized Ca2+ signals occur during phagocytosis, although their functional impact on the phagocytic process has been debated. After nearly 40 years of research, a consensus may now be reached that although not strictly required, Ca2+ signals render phagocytic ingestion and phagosome maturation more efficient, and their manipulation make an attractive avenue for therapeutic interventions. In the last decade many efforts have been made to identify the channels and regulators involved in generating and shaping phagocytic Ca2+ signals. While molecules involved in store-operated calcium entry (SOCE) of the STIM and ORAI family have taken center stage, members of the canonical, melastatin, mucolipin and vanilloid transient receptor potential (TRP), as well as purinergic P2X receptor families are now recognized to play significant roles. In this chapter, we review the recent literature on research that has linked specific Ca2+-permeable channels and regulators to phagocytic function. We highlight the fact that lipid mediators are emerging as important regulators of channel gating and that phagosomal ionic homeostasis and Ca2+ release also play essential parts. We predict that improved methodologies for measuring these factors will be critical for future advances in dissecting the intricate biology of this fascinating immune process.
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14
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Almeida N, Carrara G, Palmeira CM, Fernandes AS, Parsons M, Smith GL, Saraiva N. Stimulation of cell invasion by the Golgi Ion Channel GAAP/TMBIM4 via an H 2O 2-Dependent Mechanism. Redox Biol 2019; 28:101361. [PMID: 31693977 PMCID: PMC6838802 DOI: 10.1016/j.redox.2019.101361] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/18/2019] [Accepted: 10/21/2019] [Indexed: 02/06/2023] Open
Abstract
The mechanisms by which the Golgi apparatus (GA) impacts on cell invasion are poorly understood. The human Golgi Anti-Apoptotic Protein (hGAAP, also known as TMBIM4) is a highly conserved Golgi cation channel that modulates intracellular Ca2+ fluxes. Human GAAP is expressed in all human tissues, is essential for cell viability and provides resistance against a range of apoptotic stresses. Furthermore, hGAAP enhances adhesion and cell migration by increasing the turnover of focal adhesions due to activation of store-operated Ca2+ entry. Here, we describe a GA-derived mechanism that controls cell invasion. The overexpression of hGAAP stimulates 3-dimensional proteolytic cell invasion by a mechanism that is dependent on the accumulation of intracellular hydrogen peroxide, which might be produced by the hGAAP-dependent stimulation of mitochondrial respiration. These findings provide new insight into the complex mechanisms by which Ca2+ and reactive oxygen species signaling contribute to cell invasion and to the role of the GA in these processes.
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Affiliation(s)
- Nuno Almeida
- CBIOS, Universidade Lusófona Research Center for Biosciences & Health Technologies, Campo Grande 376, Lisbon, 1749-024, Portugal
| | - Guia Carrara
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Carlos M Palmeira
- Department of Life Sciences, University of Coimbra, Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Ana S Fernandes
- CBIOS, Universidade Lusófona Research Center for Biosciences & Health Technologies, Campo Grande 376, Lisbon, 1749-024, Portugal
| | - Maddy Parsons
- Randall Centre for Cell and Molecular Biophysics, King's College London, Guys Campus, London, SE1 1UL, UK
| | - Geoffrey L Smith
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Nuno Saraiva
- CBIOS, Universidade Lusófona Research Center for Biosciences & Health Technologies, Campo Grande 376, Lisbon, 1749-024, Portugal.
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15
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Junjappa RP, Kim HK, Park SY, Bhattarai KR, Kim KW, Soh JW, Kim HR, Chae HJ. Expression of TMBIM6 in Cancers: The Involvement of Sp1 and PKC. Cancers (Basel) 2019; 11:cancers11070974. [PMID: 31336725 PMCID: PMC6678130 DOI: 10.3390/cancers11070974] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 06/28/2019] [Accepted: 07/08/2019] [Indexed: 12/29/2022] Open
Abstract
Transmembrane Bax Inhibitor Motif-containing 6 (TMBIM6) is upregulated in several cancer types and involved in the metastasis. Specific downregulation of TMBIM6 results in cancer cell death. However, the TMBIM6 gene transcriptional regulation in normal and cancer cells is least studied. Here, we identified the core promoter region (−133/+30 bp) sufficient for promoter activity of TMBIM6 gene. Reporter gene expression with mutations at transcription factor binding sites, EMSA, supershift, and ChIP assays demonstrated that Sp1 is an essential transcription factor for basal promoter activity of TMBIM6. The TMBIM6 mRNA expression was increased with Sp1 levels in a concentration dependent manner. Ablation of Sp1 through siRNA or inhibition with mithramycin-A reduced the TMBIM6 mRNA expression. We also found that the protein kinase-C activation stimulates promoter activity and endogenous TMBIM6 mRNA by 2- to 2.5-fold. Additionally, overexpression of active mutants of PKCι, PKCε, and PKCδ increased TMBIM6 expression by enhancing nuclear translocation of Sp1. Immunohistochemistry analyses confirmed that the expression levels of PKCι, Sp1, and TMBIM6 were correlated with one another in samples from human breast, prostate, and liver cancer patients. Altogether, this study suggests the involvement of Sp1 in basal transcription and PKC in the enhanced expression of TMBIM6 in cancer.
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Affiliation(s)
- Raghu Patil Junjappa
- Department of Pharmacology and New Drug Development Research Institute, Chonbuk National University Medical School, Jeonju 54896, Korea
| | - Hyun-Kyoung Kim
- Department of Pharmacology and New Drug Development Research Institute, Chonbuk National University Medical School, Jeonju 54896, Korea
| | - Seong Yeol Park
- Department of Pharmacology and New Drug Development Research Institute, Chonbuk National University Medical School, Jeonju 54896, Korea
| | - Kashi Raj Bhattarai
- Department of Pharmacology and New Drug Development Research Institute, Chonbuk National University Medical School, Jeonju 54896, Korea
| | - Kyung-Woon Kim
- Animal Biotechnology Division, National Institute of Animal Science, Rural Development Administration (RDA), Wanju-gun, Chonbuk 54875, Korea
| | - Jae-Won Soh
- Department of Chemistry, Inha University, Incheon 402-751, Korea
| | - Hyung-Ryong Kim
- College of Dentistry, Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 31116, Korea.
| | - Han-Jung Chae
- Department of Pharmacology and New Drug Development Research Institute, Chonbuk National University Medical School, Jeonju 54896, Korea.
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16
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Aryal YP, Neupane S, Adhikari N, An C, Ha J, Kwon T, Yamamoto H, Jung J, Park E, Kim J, Cho S, Sohn W, Lee Y, Chae H, Kim H, Kim J. An endoplasmic reticulum stress regulator,
Tmbim6
, modulates secretory stage of mice molar. J Cell Physiol 2019; 234:20354-20365. [DOI: 10.1002/jcp.28635] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 03/21/2019] [Accepted: 03/25/2019] [Indexed: 01/06/2023]
Affiliation(s)
- Yam Prasad Aryal
- Department of Biochemistry, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Sanjiv Neupane
- Department of Biochemistry, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Nirpesh Adhikari
- Department of Biochemistry, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Chang‐Hyeon An
- Department of Oral and Maxillofacial Radiology, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Jung‐Hong Ha
- Department of Conservative Dentistry, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Tae‐Yub Kwon
- Department of Dental Biomaterials, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Hitoshi Yamamoto
- Department of Histology and Developmental Biology Tokyo Dental College Tokyo Japan
| | - Jae‐Kwang Jung
- Department of Oral Medicine, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Eui‐Kyun Park
- Department of Oral Pathology and Regenerative Medicine, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Ji‐Youn Kim
- Department of Dental Hygiene Gachon University Incheon Korea
| | - Sung‐Won Cho
- Division in Anatomy and Developmental Biology, Department of Oral Biology Yonsei University College of Dentistry Seoul Korea
| | - Wern‐Joo Sohn
- Pre‐Major of Cosmetics and Pharmaceutics Daegu Haany University Gyeongsan Korea
| | - Youngkyun Lee
- Department of Biochemistry, School of Dentistry, IHBR Kyungpook National University Daegu Korea
| | - Han‐Jung Chae
- Department of Pharmacology and New Drug Development Institute Chonbuk National University Jeonju Korea
| | - Hyung‐Ryong Kim
- Institute of Tissue Regeneration Engineering (ITREN) Dankook University Cheonan Korea
| | - Jae‐Young Kim
- Department of Biochemistry, School of Dentistry, IHBR Kyungpook National University Daegu Korea
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17
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Ion and pH Sensitivity of a TMBIM Ca 2+ Channel. Structure 2019; 27:1013-1021.e3. [PMID: 30930064 DOI: 10.1016/j.str.2019.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 01/25/2019] [Accepted: 02/28/2019] [Indexed: 12/12/2022]
Abstract
The anti-apoptotic transmembrane Bax inhibitor motif (TMBIM) containing protein family regulates Ca2+ homeostasis, cell death, and the progression of diseases including cancers. The recent crystal structures of the TMBIM homolog BsYetJ reveal a conserved Asp171-Asp195 dyad that is proposed in regulating a pH-dependent Ca2+ translocation. Here we show that BsYetJ mediates Ca2+ fluxes in permeabilized mammalian cells, and its interaction with Ca2+ is sensitive to protons and other cations. We report crystal structures of BsYetJ in additional states, revealing the flexibility of the dyad in a closed state and a pore-opening mechanism. Functional studies show that the dyad is responsible for both Ca2+ affinity and pH dependence. Computational simulations suggest that protonation of Asp171 weakens its interaction with Arg60, leading to an open state. Our integrated analysis provides insights into the regulation of the BsYetJ Ca2+ channel that may inform understanding of human TMBIM proteins regarding their roles in cell death and diseases.
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18
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Bedhiafi T, Charradi K, Azaiz MB, Mahmoudi M, Msakni I, Jebari K, Bouziani A, Limam F, Aouani E. Supplementation of grape seed and skin extract to orlistat therapy prevents high-fat diet-induced murine spleen lipotoxicity. Appl Physiol Nutr Metab 2018; 43:782-794. [PMID: 29514007 DOI: 10.1139/apnm-2017-0743] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2023]
Abstract
Spleen is the largest lymphoid organ and obesity is related to an elevated risk of immunity dysfunction. The mechanism whereby fat adversely affects the spleen is poorly understood. This study was designed to assess the effectiveness of grape seed and skin extract (GSSE) and orlistat (Xenical, Xe) on high-fat diet (HFD)-induced spleen lipotoxicity. Obese rats were treated either with GSSE (4 g/kg body weight) or Xe (2 mg/kg body weight) or GSSE+Xe and monitored for weight loss for 3 months. Animals were then sacrificed and their spleen used for the evaluation of lipotoxicity-induced oxidative stress and inflammation as well as the putative protection afforded by GSSE and Xe treatment. HFD induced body weight gain and glycogen accumulation into the spleen; ectopic deposition of cholesterol and triglycerides and an oxidative stress characterized by increased lipoperoxidation and carbonylation; inhibition of antioxidant enzyme activities, such as catalase, glutathione peroxidase, and superoxide dismutase; depletion of zinc and copper; and a concomitant increase in calcium. HFD also increased plasma pro-inflammatory cytokines, such as interleukin (IL)-6, IL-17A, tumour necrosis factor alpha, and C-reactive protein, and decreased plasma IL-10 and adiponectin. Importantly, GSSE counteracted all the deleterious effects of HFD on spleen (i.e., lipotoxicity, oxidative stress, and inflammation) and the best protection was obtained when combining Xe+GSSE. Combining GSSE with Xe prevented against fat-induced spleen lipotoxicity, oxidative stress, and inflammation; this combination may be beneficial in other diseases related to the spleen.
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Affiliation(s)
- Takwa Bedhiafi
- a Faculty of Sciences of Bizerte, University of Carthage, 7021 Jarzouna, Tunisia
- b Laboratory of Bioactive Substances, Center of Biotechnology of Borj Cedria, BP 901, 2050 Hammam Lif, Tunisia
| | - Kamel Charradi
- a Faculty of Sciences of Bizerte, University of Carthage, 7021 Jarzouna, Tunisia
- b Laboratory of Bioactive Substances, Center of Biotechnology of Borj Cedria, BP 901, 2050 Hammam Lif, Tunisia
| | - Mouna Ben Azaiz
- c Immunology Department, Military Hospital of Tunis, Tunis, 1008, Tunisia
| | - Mohamed Mahmoudi
- a Faculty of Sciences of Bizerte, University of Carthage, 7021 Jarzouna, Tunisia
- b Laboratory of Bioactive Substances, Center of Biotechnology of Borj Cedria, BP 901, 2050 Hammam Lif, Tunisia
| | - Issam Msakni
- d Anatomy and Cyto-Pathology Department, Military Hospital, Mont-Fleury, Tunis, 1008, Tunisia
| | - Khawla Jebari
- a Faculty of Sciences of Bizerte, University of Carthage, 7021 Jarzouna, Tunisia
- b Laboratory of Bioactive Substances, Center of Biotechnology of Borj Cedria, BP 901, 2050 Hammam Lif, Tunisia
| | - Ammar Bouziani
- d Anatomy and Cyto-Pathology Department, Military Hospital, Mont-Fleury, Tunis, 1008, Tunisia
| | - Ferid Limam
- b Laboratory of Bioactive Substances, Center of Biotechnology of Borj Cedria, BP 901, 2050 Hammam Lif, Tunisia
| | - Ezzedine Aouani
- a Faculty of Sciences of Bizerte, University of Carthage, 7021 Jarzouna, Tunisia
- b Laboratory of Bioactive Substances, Center of Biotechnology of Borj Cedria, BP 901, 2050 Hammam Lif, Tunisia
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Del Favero G, Woelflingseder L, Janker L, Neuditschko B, Seriani S, Gallina P, Sbaizero O, Gerner C, Marko D. Deoxynivalenol induces structural alterations in epidermoid carcinoma cells A431 and impairs the response to biomechanical stimulation. Sci Rep 2018; 8:11351. [PMID: 30054545 PMCID: PMC6063857 DOI: 10.1038/s41598-018-29728-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 07/12/2018] [Indexed: 12/12/2022] Open
Abstract
Morphology together with the capability to respond to surrounding stimuli are key elements governing the spatial interaction of living cells with the environment. In this respect, biomechanical stimulation can trigger significant physiological cascades that can potentially modulate toxicity. Deoxynivalenol (DON, vomitoxin) is one of the most prevalent mycotoxins produced by Fusarium spp. and it was used to explore the delicate interaction between biomechanical stimulation and cytotoxicity in A431 cells. In fact, in addition of being a food contaminant, DON is a relevant toxin for several organ systems. The combination between biomechanical stimulation and the mycotoxin revealed how DON can impair crucial functions affecting cellular morphology, tubulin and lysosomes at concentrations even below those known to be cytotoxic in routine toxicity studies. Sub-toxic concentrations of DON (0.1-1 μM) impaired the capability of A431 cells to respond to a biomechanical stimulation that normally sustains trophic effects in these cells. Moreover, the effects of DON (0.1-10 μM) were partially modulated by the application of uniaxial stretching (0.5 Hz, 24 h, 15% deformation). Ultimately, proteomic analysis revealed the potential of DON to alter several proteins necessary for cell adhesion and cytoskeletal modulation suggesting a molecular link between biomechanics and the cytotoxic potential of the mycotoxin.
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Affiliation(s)
- Giorgia Del Favero
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währingerstr. 38-40, 1090, Vienna, Austria.
| | - Lydia Woelflingseder
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währingerstr. 38-40, 1090, Vienna, Austria
| | - Lukas Janker
- Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Währingerstr. 38-40, 1090, Vienna, Austria
| | - Benjamin Neuditschko
- Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Währingerstr. 38-40, 1090, Vienna, Austria
| | - Stefano Seriani
- Department of Engineering and Architecture, University of Trieste Via A, Valerio 10, 34127, Trieste, Italy
- Robotik und Mechatronik Zentrum, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen, Germany
| | - Paolo Gallina
- Department of Engineering and Architecture, University of Trieste Via A, Valerio 10, 34127, Trieste, Italy
| | - Orfeo Sbaizero
- Department of Engineering and Architecture, University of Trieste Via A, Valerio 10, 34127, Trieste, Italy
| | - Christopher Gerner
- Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Währingerstr. 38-40, 1090, Vienna, Austria
| | - Doris Marko
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währingerstr. 38-40, 1090, Vienna, Austria
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Metabolic profiling of visceral adipose tissue from obese subjects with or without metabolic syndrome. Biochem J 2018; 475:1019-1035. [PMID: 29437994 DOI: 10.1042/bcj20170604] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Revised: 01/30/2018] [Accepted: 01/31/2018] [Indexed: 12/15/2022]
Abstract
Obesity represents one of the most complex public health challenges and has recently reached epidemic proportions. Obesity is also considered to be primarily responsible for the rising prevalence of metabolic syndrome, defined as the coexistence in the same individual of several risk factors for atherosclerosis, including dyslipidemia, hypertension and hyperglycemia, as well as for cancer. Additionally, the presence of three of the five risk factors (abdominal obesity, low high-density lipoprotein cholesterol, high triglycerides, high fasting glucose and high blood pressure) characterizes metabolic syndrome, which has serious clinical consequences. The current study was conducted in order to identify metabolic differences in visceral adipose tissue (VAT) collected from obese (body mass index 43-48) human subjects who were diagnosed with metabolic syndrome, obese individuals who were metabolically healthy and nonobese healthy controls. Extensive gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS/MS) analyses were used to obtain the untargeted VAT metabolomic profiles of 481 metabolites belonging to all biochemical pathways. Our results indicated consistent increases in oxidative stress markers from the pathologically obese samples in addition to subtle markers of elevated glucose levels that may be consistent with metabolic syndrome. In the tissue derived from the pathologically obese subjects, there were significantly elevated levels of plasmalogens, which may be increased in response to oxidative changes in addition to changes in glycerolphosphorylcholine, glycerolphosphorylethanolamine glycerolphosphorylserine, ceramides and sphingolipids. These data could be potentially helpful for recognizing new pathways that underlie the metabolic-vascular complications of obesity and may lead to the development of innovative targeted therapies.
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Carrara G, Parsons M, Saraiva N, Smith GL. Golgi anti-apoptotic protein: a tale of camels, calcium, channels and cancer. Open Biol 2018; 7:rsob.170045. [PMID: 28469007 PMCID: PMC5451544 DOI: 10.1098/rsob.170045] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 04/10/2017] [Indexed: 12/11/2022] Open
Abstract
Golgi anti-apoptotic protein (GAAP), also known as transmembrane Bax inhibitor-1 motif-containing 4 (TMBIM4) or Lifeguard 4 (Lfg4), shares remarkable amino acid conservation with orthologues throughout eukaryotes, prokaryotes and some orthopoxviruses, suggesting a highly conserved function. GAAPs regulate Ca2+ levels and fluxes from the Golgi and endoplasmic reticulum, confer resistance to a broad range of apoptotic stimuli, promote cell adhesion and migration via the activation of store-operated Ca2+ entry, are essential for the viability of human cells, and affect orthopoxvirus virulence. GAAPs are oligomeric, multi-transmembrane proteins that are resident in Golgi membranes and form cation-selective ion channels that may explain the multiple functions of these proteins. Residues contributing to the ion-conducting pore have been defined and provide the first clues about the mechanistic link between these very different functions of GAAP. Although GAAPs are naturally oligomeric, they can also function as monomers, a feature that distinguishes them from other virus-encoded ion channels that must oligomerize for function. This review summarizes the known functions of GAAPs and discusses their potential importance in disease.
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Affiliation(s)
- Guia Carrara
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Maddy Parsons
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Nuno Saraiva
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK .,CBIOS, Universidade Lusófona Research Centre for Biosciences and Health Technologies, Campo Grande 376, Lisbon 1749-024, Portugal
| | - Geoffrey L Smith
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
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Shi L, Wang Z, Liu X, Li M, Zhang S, Song X. Bax inhibitor-1 is required for resisting the Early Brain Injury induced by subarachnoid hemorrhage through regulating IRE1-JNK pathway. Neurol Res 2018; 40:189-196. [PMID: 29334839 DOI: 10.1080/01616412.2018.1424699] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Lei Shi
- Department of Neurosurgery, Zhumadian Central Hospital, Zhumadian, China
| | - Zaizong Wang
- Department of Neurosurgery, Zhumadian Central Hospital, Zhumadian, China
| | - Xianjin Liu
- Department of Neurosurgery, Zhumadian Central Hospital, Zhumadian, China
| | - Mao Li
- Department of Neurosurgery, Zhumadian Central Hospital, Zhumadian, China
| | - Shangfei Zhang
- Department of Neurosurgery, Zhumadian Central Hospital, Zhumadian, China
| | - Xiaobin Song
- Department of Neurosurgery, The First Affiliated Hospital of Kunming Medical College, Kunming, China
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M'Angale PG, Staveley BE. Bax-inhibitor-1 knockdown phenotypes are suppressed by Buffy and exacerbate degeneration in a Drosophila model of Parkinson disease. PeerJ 2017; 5:e2974. [PMID: 28243526 PMCID: PMC5322759 DOI: 10.7717/peerj.2974] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 01/10/2017] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Bax inhibitor-1 (BI-1) is an evolutionarily conserved cytoprotective transmembrane protein that acts as a suppressor of Bax-induced apoptosis by regulation of endoplasmic reticulum stress-induced cell death. We knocked down BI-1 in the sensitive dopa decarboxylase (Ddc) expressing neurons of Drosophila melanogaster to investigate its neuroprotective functions. We additionally sought to rescue the BI-1-induced phenotypes by co-expression with the pro-survival Buffy and determined the effect of BI-1 knockdown on the neurodegenerative α-synuclein-induced Parkinson disease (PD) model. METHODS We used organismal assays to assess longevity of the flies to determine the effect of the altered expression of BI-1 in the Ddc-Gal4-expressing neurons by employing two RNAi transgenic fly lines. We measured the locomotor ability of these RNAi lines by computing the climbing indices of the climbing ability and compared them to a control line that expresses the lacZ transgene. Finally, we performed biometric analysis of the developing eye, where we counted the number of ommatidia and calculated the area of ommatidial disruption. RESULTS The knockdown of BI-1 in these neurons was achieved under the direction of the Ddc-Gal4 transgene and resulted in shortened lifespan and precocious loss of locomotor ability. The co-expression of Buffy, the Drosophila anti-apoptotic Bcl-2 homologue, with BI-1-RNAi resulted in suppression of the reduced lifespan and impaired climbing ability. Expression of human α-synuclein in Drosophila dopaminergic neurons results in neuronal degeneration, accompanied by the age-dependent loss in climbing ability. We exploited this neurotoxic system to investigate possible BI-1 neuroprotective function. The co-expression of α-synuclein with BI-1-RNAi results in a slight decrease in lifespan coupled with an impairment in climbing ability. In supportive experiments, we employed the neuron-rich Drosophila compound eye to investigate subtle phenotypes that result from altered gene expression. The knockdown of BI-1 in the Drosophila developing eye under the direction of the GMR-Gal4 transgene results in reduced ommatidia number and increased disruption of the ommatidial array. Similarly, the co-expression of BI-1-RNAi with Buffy results in the suppression of the eye phenotypes. The expression of α-synuclein along with the knockdown of BI-1 resulted in reduction of ommatidia number and more disruption of the ommatidial array. CONCLUSION Knockdown of BI-1 in the dopaminergic neurons of Drosophila results in a shortened lifespan and premature loss in climbing ability, phenotypes that appear to be strongly associated with models of PD in Drosophila, and which are suppressed upon overexpression of Buffy and worsened by co-expression with α-synuclein. This suggests that BI-1 is neuroprotective and its knockdown can be counteracted by the overexpression of the pro-survival Bcl-2 homologue.
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Affiliation(s)
- P Githure M'Angale
- Department of Biology, Memorial University of Newfoundland , St. John's, NL , Canada
| | - Brian E Staveley
- Department of Biology, Memorial University of Newfoundland , St. John's, NL , Canada
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