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Muramoto M, Mineoka N, Fukuda K, Kuriyama S, Masatani T, Fujita A. Coordinated regulation of phosphatidylinositol 4-phosphate and phosphatidylserine levels by Osh4p and Osh5p is an essential regulatory mechanism in autophagy. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184308. [PMID: 38437942 DOI: 10.1016/j.bbamem.2024.184308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 01/26/2024] [Accepted: 02/26/2024] [Indexed: 03/06/2024]
Abstract
Macroautophagy (hereafter autophagy) is an intracellular degradative pathway in budding yeast cells. Certain lipid types play essential roles in autophagy; yet the precise mechanisms regulating lipid composition during autophagy remain unknown. Here, we explored the role of the Osh family proteins in the modulating lipid composition during autophagy in budding yeast. Our results showed that osh1-osh7∆ deletions lead to autophagic dysfunction, with impaired GFP-Atg8 processing and the absence of autophagosomes and autophagic bodies in the cytosol and vacuole, respectively. Freeze-fracture electron microscopy (EM) revealed elevated phosphatidylinositol 4-phosphate (PtdIns(4)P) levels in cytoplasmic and luminal leaflets of autophagic bodies and vacuolar membranes in all deletion mutants. Phosphatidylserine (PtdSer) levels were significantly decreased in the autophagic bodies and vacuolar membranes in osh4∆ and osh5∆ mutants, whereas no significant changes were observed in other osh deletion mutants. Furthermore, we identified defects in autophagic processes in the osh4∆ and osh5∆ mutants, including rare autophagosome formation in the osh5∆ mutant and accumulation of autophagic bodies in the vacuole in the osh4∆ mutant, even in the absence of the proteinase inhibitor PMSF. These findings suggest that Osh4p and Osh5p play crucial roles in the transport of PtdSer to autophagic bodies and autophagosome membranes, respectively. The precise control of lipid composition in the membranes of autophagosomes and autophagic bodies by Osh4p and Osh5p represents an important regulatory mechanism in autophagy.
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Affiliation(s)
- Moe Muramoto
- Department of Molecular and Cell Biology and Biochemistry, Basic Veterinary Science, Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan
| | - Nanaru Mineoka
- Department of Molecular and Cell Biology and Biochemistry, Basic Veterinary Science, Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan
| | - Kayoko Fukuda
- Department of Molecular and Cell Biology and Biochemistry, Basic Veterinary Science, Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan
| | - Sayuri Kuriyama
- Department of Molecular and Cell Biology and Biochemistry, Basic Veterinary Science, Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan
| | - Tatsunori Masatani
- Laboratory of Zoonotic Diseases, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; Center for One Medicine Innovative Translational Research (COMIT), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Akikazu Fujita
- Department of Molecular and Cell Biology and Biochemistry, Basic Veterinary Science, Faculty of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan.
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2
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Wang X, Liu J, Azoitei A, Eiseler T, Meessen S, Jiang W, Zheng X, Makori AW, Eckstein M, Hartmann A, Stilgenbauer S, Elati M, Hohwieler M, Kleger A, John A, Zengerling F, Wezel F, Bolenz C, Günes C. Loss of ORP3 induces aneuploidy and promotes bladder cancer cell invasion through deregulated microtubule and actin dynamics. Cell Mol Life Sci 2023; 80:299. [PMID: 37740130 PMCID: PMC10516806 DOI: 10.1007/s00018-023-04959-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 09/24/2023]
Abstract
We have recently shown that loss of ORP3 leads to aneuploidy induction and promotes tumor formation. However, the specific mechanisms by which ORP3 contributes to ploidy-control and cancer initiation and progression is still unknown. Here, we report that ORP3 is highly expressed in ureter and bladder epithelium while its expression is downregulated in invasive bladder cancer cell lines and during tumor progression, both in human and in mouse bladder cancer. Moreover, we observed an increase in the incidence of N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN)-induced invasive bladder carcinoma in the tissue-specific Orp3 knockout mice. Experimental data demonstrate that ORP3 protein interacts with γ-tubulin at the centrosomes and with components of actin cytoskeleton. Altering the expression of ORP3 induces aneuploidy and genomic instability in telomerase-immortalized urothelial cells with a stable karyotype and influences the migration and invasive capacity of bladder cancer cell lines. These findings demonstrate a crucial role of ORP3 in ploidy-control and indicate that ORP3 is a bona fide tumor suppressor protein. Of note, the presented data indicate that ORP3 affects both cell invasion and migration as well as genome stability through interactions with cytoskeletal components, providing a molecular link between aneuploidy and cell invasion and migration, two crucial characteristics of metastatic cells.
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Affiliation(s)
- Xue Wang
- Department of Urology, Ulm University Hospital, Helmholtzstr. 10, 89081, Ulm, Germany
- Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Junnan Liu
- Department of Urology, Ulm University Hospital, Helmholtzstr. 10, 89081, Ulm, Germany
- Department of Urology, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Anca Azoitei
- Department of Urology, Ulm University Hospital, Helmholtzstr. 10, 89081, Ulm, Germany
| | - Tim Eiseler
- Department of Internal Medicine I, University Hospital, Ulm, Germany
| | - Sabine Meessen
- Department of Urology, Ulm University Hospital, Helmholtzstr. 10, 89081, Ulm, Germany
- Division of Hepatology, Department of Medicine II, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Wencheng Jiang
- Department of Urology, Ulm University Hospital, Helmholtzstr. 10, 89081, Ulm, Germany
| | - Xi Zheng
- Department of Urology, Ulm University Hospital, Helmholtzstr. 10, 89081, Ulm, Germany
- Department of Urology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, 210008, Jiangsu, China
- Institute of Urology, Nanjing University, Nanjing, 210008, Jiangsu, China
| | - Arika W Makori
- Department of Urology, Ulm University Hospital, Helmholtzstr. 10, 89081, Ulm, Germany
| | - Markus Eckstein
- Institute of Pathology, Friedrich-Alexander University, Erlangen, Germany
| | - Arndt Hartmann
- Institute of Pathology, Friedrich-Alexander University, Erlangen, Germany
| | | | - Mohamed Elati
- CANTHER, ONCOLille Institute, University of Lille, CNRS UMR 1277, Inserm U9020, 59045, Lille Cedex, France
| | - Meike Hohwieler
- Institute of Mol. Oncology and Stem Cell Biology, University Hospital, Ulm, Germany
| | - Alexander Kleger
- Institute of Mol. Oncology and Stem Cell Biology, University Hospital, Ulm, Germany
| | - Axel John
- Department of Urology, Ulm University Hospital, Helmholtzstr. 10, 89081, Ulm, Germany
| | - Friedemann Zengerling
- Department of Urology, Ulm University Hospital, Helmholtzstr. 10, 89081, Ulm, Germany
| | - Felix Wezel
- Department of Urology, Ulm University Hospital, Helmholtzstr. 10, 89081, Ulm, Germany
| | - Christian Bolenz
- Department of Urology, Ulm University Hospital, Helmholtzstr. 10, 89081, Ulm, Germany
| | - Cagatay Günes
- Department of Urology, Ulm University Hospital, Helmholtzstr. 10, 89081, Ulm, Germany.
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3
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Subra M, Antonny B, Mesmin B. New insights into the OSBP‒VAP cycle. Curr Opin Cell Biol 2023; 82:102172. [PMID: 37245352 DOI: 10.1016/j.ceb.2023.102172] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/16/2023] [Accepted: 04/24/2023] [Indexed: 05/30/2023]
Abstract
VAP-A is a major endoplasmic reticulum (ER) receptor that allows this organelle to engage numerous membrane contact sites with other organelles. One highly studied example is the formation of contact sites through VAP-A interaction with Oxysterol-binding protein (OSBP). This lipid transfer protein transports cholesterol from the ER to the trans-Golgi network owing to the counter-exchange of the phosphoinositide PI(4)P. In this review, we highlight recent studies that advance our understanding of the OSBP cycle and extend the model of lipid exchange to other cellular contexts and other physiological and pathological conditions.
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Affiliation(s)
- Mélody Subra
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 Route des Lucioles, 06560, Valbonne, France
| | - Bruno Antonny
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 Route des Lucioles, 06560, Valbonne, France.
| | - Bruno Mesmin
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 Route des Lucioles, 06560, Valbonne, France.
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4
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Zhang M, Meng L, Zhang Z, Wu J, Chen X, Wang Y, He J. The relationships of OSBPL3 expression with KI-67 expression and KRAS mutations in CRC: implications for diagnosis and prognosis. BMC Med Genomics 2022; 15:259. [PMID: 36517805 PMCID: PMC9753258 DOI: 10.1186/s12920-022-01402-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 11/23/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND OSBPL3 is overexpressed in a variety of malignancies and is closely associated with tumor growth and metastasis. However, its expression and function in colorectal cancer (CRC) are unclear. We aimed to investigate its prognostic and therapeutic value in this disease by detecting its expression in CRC and its correlation with the clinicopathological characteristics and prognosis of patients. METHODS A total of 92 CRC samples were included in this study. According to the 2020 WHO diagnostic criteria, the criteria of the American Joint Committee on Cancer (AJCC) 8th edition staging system were used. OSBPL3 and Ki-67 expression in these samples was detected by immunohistochemistry. OSBPL3 mRNA expression was detected by qRT-PCR. KRAS/NRAS mutations were detected by an amplification refractory mutation system (ARMS). Data analysis was performed using the statistical analysis software Prism 8. RESULTS OSBPL3 was found to be significantly overexpressed in CRC tumor tissues and was associated with worse progression-free survival and overall survival in patients. Additionally, OSBPL3 expression was negatively correlated with the degree of tumor differentiation. KRAS mutations were detected in approximately 32.6% of patients and were significantly associated with high OSBPL3 expression. In addition, OSBPL3 and Ki-67 expression was significantly correlated. CONCLUSIONS OSBPL3 is highly expressed in CRC samples and predicts a worse prognosis. OSBPL3 may become a new potential therapeutic target for CRC.
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Affiliation(s)
- Min Zhang
- grid.59053.3a0000000121679639Department of Pathology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001 Anhui China
| | - Lei Meng
- grid.59053.3a0000000121679639Department of Gastrointestinal Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001 Anhui China
| | - Zhaoxuan Zhang
- grid.59053.3a0000000121679639Department of Pathology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001 Anhui China
| | - Jing Wu
- grid.59053.3a0000000121679639Department of Pathology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001 Anhui China
| | - Xi Chen
- grid.59053.3a0000000121679639Department of Gastrointestinal Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001 Anhui China
| | - Yuejing Wang
- grid.186775.a0000 0000 9490 772XAnhui Medical University, Hefei, Anhui China
| | - Jie He
- grid.59053.3a0000000121679639Department of Pathology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001 Anhui China
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5
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Ondaro J, Hernandez-Eguiazu H, Garciandia-Arcelus M, Loera-Valencia R, Rodriguez-Gómez L, Jiménez-Zúñiga A, Goikolea J, Rodriguez-Rodriguez P, Ruiz-Martinez J, Moreno F, Lopez de Munain A, Holt IJ, Gil-Bea FJ, Gereñu G. Defects of Nutrient Signaling and Autophagy in Neurodegeneration. Front Cell Dev Biol 2022; 10:836196. [PMID: 35419363 PMCID: PMC8996160 DOI: 10.3389/fcell.2022.836196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/21/2022] [Indexed: 12/27/2022] Open
Abstract
Neurons are post-mitotic cells that allocate huge amounts of energy to the synthesis of new organelles and molecules, neurotransmission and to the maintenance of redox homeostasis. In neurons, autophagy is not only crucial to ensure organelle renewal but it is also essential to balance nutritional needs through the mobilization of internal energy stores. A delicate crosstalk between the pathways that sense nutritional status of the cell and the autophagic processes to recycle organelles and macronutrients is fundamental to guarantee the proper functioning of the neuron in times of energy scarcity. This review provides a detailed overview of the pathways and processes involved in the balance of cellular energy mediated by autophagy, which when defective, precipitate the neurodegenerative cascade of Parkinson’s disease, frontotemporal dementia, amyotrophic lateral sclerosis or Alzheimer’s disease.
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Affiliation(s)
- Jon Ondaro
- Department of Neuroscience, Biodonostia Health Research Institute (IIS Biodonostia), San Sebastian, Spain.,Center for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Haizea Hernandez-Eguiazu
- Department of Neuroscience, Biodonostia Health Research Institute (IIS Biodonostia), San Sebastian, Spain.,Center for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Maddi Garciandia-Arcelus
- Department of Neuroscience, Biodonostia Health Research Institute (IIS Biodonostia), San Sebastian, Spain.,Center for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Raúl Loera-Valencia
- Department of Neurology, Care Sciences and Society, Center for Alzheimer Research, Karolinska Institutet (KI), Stockholm, Sweden
| | - Laura Rodriguez-Gómez
- Department of Neuroscience, Biodonostia Health Research Institute (IIS Biodonostia), San Sebastian, Spain.,Center for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Andrés Jiménez-Zúñiga
- Department of Neuroscience, Biodonostia Health Research Institute (IIS Biodonostia), San Sebastian, Spain.,Center for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Julen Goikolea
- Department of Neurology, Care Sciences and Society, Center for Alzheimer Research, Karolinska Institutet (KI), Stockholm, Sweden
| | - Patricia Rodriguez-Rodriguez
- Department of Neurology, Care Sciences and Society, Center for Alzheimer Research, Karolinska Institutet (KI), Stockholm, Sweden
| | - Javier Ruiz-Martinez
- Department of Neuroscience, Biodonostia Health Research Institute (IIS Biodonostia), San Sebastian, Spain.,Center for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Madrid, Spain.,Donostia University Hospital, San Sebastian, Spain
| | - Fermín Moreno
- Department of Neuroscience, Biodonostia Health Research Institute (IIS Biodonostia), San Sebastian, Spain.,Center for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Madrid, Spain.,Donostia University Hospital, San Sebastian, Spain
| | - Adolfo Lopez de Munain
- Department of Neuroscience, Biodonostia Health Research Institute (IIS Biodonostia), San Sebastian, Spain.,Center for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Madrid, Spain.,Donostia University Hospital, San Sebastian, Spain
| | - Ian James Holt
- Department of Neuroscience, Biodonostia Health Research Institute (IIS Biodonostia), San Sebastian, Spain.,Center for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Madrid, Spain.,Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, Faculty of Brain Sciences, University College London, London, United Kingdom.,IKERBASQUE Basque Foundation for Science, Bilbao, Spain
| | - Francisco Javier Gil-Bea
- Department of Neuroscience, Biodonostia Health Research Institute (IIS Biodonostia), San Sebastian, Spain.,Center for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Gorka Gereñu
- Department of Neuroscience, Biodonostia Health Research Institute (IIS Biodonostia), San Sebastian, Spain.,Center for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Madrid, Spain.,Department of Physiology, Faculty of Medicine and Nursing, University of Basque Country (UPV-EHU), Leioa, Spain
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6
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Chen MM, Yang SR, Wang J, Fang YL, Peng YL, Fan J. Fungal oxysterol-binding protein-related proteins promote pathogen virulence and activate plant immunity. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2125-2141. [PMID: 34864987 DOI: 10.1093/jxb/erab530] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 12/02/2021] [Indexed: 06/13/2023]
Abstract
Oxysterol-binding protein-related proteins (ORPs) are a conserved class of lipid transfer proteins that are closely involved in multiple cellular processes in eukaryotes, but their roles in plant-pathogen interactions are mostly unknown. We show that transient expression of ORPs of Magnaporthe oryzae (MoORPs) in Nicotiana benthamina plants triggered oxidative bursts and cell death; treatment of tobacco Bright Yellow-2 suspension cells with recombinant MoORPs elicited the production of reactive oxygen species. Despite ORPs being normally described as intracellular proteins, we detected MoORPs in fungal culture filtrates and intercellular fluids from barley plants infected with the fungus. More importantly, infiltration of Arabidopsis plants with recombinant Arabidopsis or fungal ORPs activated oxidative bursts, callose deposition, and PR1 gene expression, and enhanced plant disease resistance, implying that ORPs may function as endogenous and exogenous danger signals triggering plant innate immunity. Extracellular application of fungal ORPs exerted an opposite impact on salicylic acid and jasmonic acid/ethylene signaling pathways. Brassinosteroid Insensitive 1-associated Kinase 1 was dispensable for the ORP-activated defense. Besides, simultaneous knockout of MoORP1 and MoORP3 abolished fungal colony radial growth and conidiation, whereas double knockout of MoORP1 and MoORP2 compromised fungal virulence on barley and rice plants. These observations collectively highlight the multifaceted role of MoORPs in the modulation of plant innate immunity and promotion of fungal development and virulence in M. oryzae.
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Affiliation(s)
- Meng-Meng Chen
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Si-Ru Yang
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jian Wang
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Ya-Li Fang
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - You-Liang Peng
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China
| | - Jun Fan
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
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Jiang D, Wu X, Sun X, Tan W, Dai X, Xie Y, Du A, Zhao Q. Bone mesenchymal stem cell-derived exosomal microRNA-7-5p inhibits progression of acute myeloid leukemia by targeting OSBPL11. J Nanobiotechnology 2022; 20:29. [PMID: 35012554 PMCID: PMC8744354 DOI: 10.1186/s12951-021-01206-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/12/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Acute myeloid leukemia (AML) is a malignant clonal disease of hematopoietic stem- and progenitor-cell origin. AML features massive proliferation of abnormal blasts and leukemia cells in the bone marrow and the inhibition of normal hematopoiesis at onset. Exosomes containing proteins or nucleic acids are secreted by cells; they participate in intercellular communication and serve as key modulators of hematopoiesis. The purpose of this study was to investigate the effects of exosomes derived from bone marrow mesenchymal stem cells (BMSCs) on the regulation of AML and the underlying mechanisms mediated by microRNA (miRNA). METHODS Dysregulated miR-7-5p in AML patients was identified using qRT-PCR and its clinical significance was explored. Bioinformatic analysis revealed the target gene OSBPL11 that could be regulated by miR-7-5p. The findings were validated using a dual-luciferase reporter assay and western blotting. The functional genes of the PI3K/AKT/mTOR signaling pathway were identified, and the functional significance of miR-7-5p in AML cells was determined using a functional recovery assay. AML cells were co-cultured with exosomes originating from BMSCs overexpressing miR-7-5p to determine cell-cell regulation by Exo-miR-7-5p, as well as in vitro and in vivo functional validation via gain- and loss-of-function methods. RESULTS Expression of miR-7-5p was decreased in AML patients and cells. Overexpression of miR-7-5p curbed cellular proliferation and promoted apoptosis. Overexpression of OSBPL11 reversed the tumorigenic properties of miR-7-5p in AML cells in vitro. Exo-miR-7-5p derived from BMSCs induced formation of AML cells prone to apoptosis and a low survival rate, with OSBPL11 expression inhibited through the PI3K/AKT/mTOR signaling pathway. Exo-miR-7-5p derived from BMSCs exhibited tumor homing effects in vitro and in vivo, and inhibited AML development. CONCLUSIONS Exo-miR-7-5p derived from BMSCs negatively regulates OSBPL11 by suppressing the phosphorylation of the PI3K/AKT/mTOR signaling pathway, thereby inhibiting AML proliferation and promoting apoptosis. The data will inform the development of AML therapies based on BMSC-derived exosomes.
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Affiliation(s)
- Duanfeng Jiang
- Department of Hematology, Second Affiliated Hospital of Hainan Medical College, Haikou, 570311, People's Republic of China.,Department of Hematology, The Third Xiangya Hospital, Central South University, Changsha, 410013, People's Republic of China
| | - Xin Wu
- Department of Orthopedics, Third Xiangya Hospital, Central South University, Changsha, 410013, People's Republic of China
| | - Xiaoying Sun
- Nursing School, Soochow University, Suzhou, 215000, People's Republic of China.,Department of Emergency, The Qinghai Provincial People's Hospital, Xining, 810007, People's Republic of China
| | - Wei Tan
- Department of Orthopedics, Third Xiangya Hospital, Central South University, Changsha, 410013, People's Republic of China
| | - Xin Dai
- Department of Hematology, The Qinghai Provincial People's Hospital, Xining, 810007, People's Republic of China
| | - Youbang Xie
- Department of Hematology, The Qinghai Provincial People's Hospital, Xining, 810007, People's Republic of China
| | - Ashuai Du
- Department of Infectious Diseases, Guizhou Provincial People's Hospital, Guiyang, 550002, People's Republic of China.
| | - Qiangqiang Zhao
- Department of Hematology, The Qinghai Provincial People's Hospital, Xining, 810007, People's Republic of China. .,Department of Blood Transfusion, The Third Xiangya Hospital, Central South University, Changsha, 410013, People's Republic of China.
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8
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Identification of hub genes in colorectal cancer based on weighted gene co-expression network analysis and clinical data from The Cancer Genome Atlas. Biosci Rep 2021; 41:229248. [PMID: 34308980 PMCID: PMC8314434 DOI: 10.1042/bsr20211280] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/28/2021] [Accepted: 07/13/2021] [Indexed: 12/12/2022] Open
Abstract
Colorectal cancer (CRC) is one of the most common tumors worldwide and is associated with high mortality. Here we performed bioinformatics analysis, which we validated using immunohistochemistry in order to search for hub genes that might serve as biomarkers or therapeutic targets in CRC. Based on data from The Cancer Genome Atlas (TCGA), we identified 4832 genes differentially expressed between CRC and normal samples (1562 up-regulated and 3270 down-regulated in CRC). Gene ontology (GO) analysis showed that up-regulated genes were enriched mainly in organelle fission, cell cycle regulation, and DNA replication; down-regulated genes were enriched primarily in the regulation of ion transmembrane transport and ion homeostasis. Weighted gene co-expression network analysis (WGCNA) identified eight gene modules that were associated with clinical characteristics of CRC patients, including brown and blue modules that were associated with cancer onset. Analysis of the latter two hub modules revealed the following six hub genes: adhesion G protein-coupled receptor B3 (BAI3, also known as ADGRB3), cyclin F (CCNF), cytoskeleton-associated protein 2 like (CKAP2L), diaphanous-related formin 3 (DIAPH3), oxysterol binding protein-like 3 (OSBPL3), and RERG-like protein (RERGL). Expression levels of these hub genes were associated with prognosis, based on Kaplan–Meier survival analysis of data from the Gene Expression Profiling Interactive Analysis database. Immunohistochemistry of CRC tumor tissues confirmed that OSBPL3 is up-regulated in CRC. Our findings suggest that CCNF, DIAPH3, OSBPL3, and RERGL may be useful as therapeutic targets against CRC. BAI3 and CKAP2L may be novel biomarkers of the disease.
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9
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Cariati I, Masuelli L, Bei R, Tancredi V, Frank C, D’Arcangelo G. Neurodegeneration in Niemann-Pick Type C Disease: An Updated Review on Pharmacological and Non-Pharmacological Approaches to Counteract Brain and Cognitive Impairment. Int J Mol Sci 2021; 22:ijms22126600. [PMID: 34202978 PMCID: PMC8234817 DOI: 10.3390/ijms22126600] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 01/08/2023] Open
Abstract
Niemann–Pick type C (NPC) disease is an autosomal recessive storage disorder, characterized by abnormal sequestration of unesterified cholesterol in the late endo-lysosomal system of cells. Progressive neurological deterioration and the onset of symptoms, such as ataxia, seizures, cognitive decline, and severe dementia, are pathognomonic features of the disease. In addition, different pathological similarities, including degeneration of hippocampal and cortical neurons, hyperphosphorylated tau, and neurofibrillary tangle formation, have been identified between NPC disease and other neurodegenerative pathologies. However, the underlying pathophysiological mechanisms are not yet well understood, and even a real cure to counteract neurodegeneration has not been identified. Therefore, the combination of current pharmacological therapies, represented by miglustat and cyclodextrin, and non-pharmacological approaches, such as physical exercise and appropriate diet, could represent a strategy to improve the quality of life of NPC patients. Based on this evidence, in our review we focused on the neurodegenerative aspects of NPC disease, summarizing the current knowledge on the molecular and biochemical mechanisms responsible for cognitive impairment, and suggesting physical exercise and nutritional treatments as additional non-pharmacologic approaches to reduce the progression and neurodegenerative course of NPC disease.
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Affiliation(s)
- Ida Cariati
- Medical-Surgical Biotechnologies and Translational Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy;
- Department of Clinical Sciences and Translational Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy;
| | - Laura Masuelli
- Department of Experimental Medicine, University of Rome “Sapienza”, Viale Regina Elena 324, 00161 Rome, Italy;
| | - Roberto Bei
- Department of Clinical Sciences and Translational Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy;
| | - Virginia Tancredi
- Department of Systems Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy;
- Centre of Space Bio-Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy
| | - Claudio Frank
- UniCamillus-Saint Camillus International University of Health Sciences, Via di Sant’Alessandro 8, 00131 Rome, Italy;
| | - Giovanna D’Arcangelo
- Department of Systems Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy;
- Centre of Space Bio-Medicine, “Tor Vergata” University of Rome, Via Montpellier 1, 00133 Rome, Italy
- Correspondence:
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Alabduljabbar S, Zaidan SA, Lakshmanan AP, Terranegra A. Personalized Nutrition Approach in Pregnancy and Early Life to Tackle Childhood and Adult Non-Communicable Diseases. Life (Basel) 2021; 11:life11060467. [PMID: 34073649 PMCID: PMC8224671 DOI: 10.3390/life11060467] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/05/2021] [Accepted: 05/11/2021] [Indexed: 02/07/2023] Open
Abstract
The development of childhood and adult non-communicable diseases (NCD) is associated with environmental factors, starting from intrauterine life. A new theory finds the roots of epigenetic programming in parental gametogenesis, continuing during embryo development, fetal life, and finally in post-natal life. Maternal health status and poor nutrition are widely recognized as implications in the onset of childhood and adult diseases. Early nutrition, particularly breastfeeding, also plays a primary role in affecting the health status of an individual later in life. A poor maternal diet during pregnancy and lack of breastfeeding can cause a nutrient deficiency that affects the gut microbiota, and acts as a cofactor for many pathways, impacting the epigenetic controls and transcription of genes involved in the metabolism, angiogenesis, and other pathways, leading to NCDs in adult life. Both maternal and fetal genetic backgrounds also affect nutrient adsorption and functioning at the cellular level. This review discusses the most recent evidence on maternal nutrition and breastfeeding in the development of NCD, the potentiality of the omics technologies in uncovering the molecular mechanisms underlying it, with the future prospective of applying a personalized nutrition approach to prevent and treat NCD from the beginning of fetal life.
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11
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Circulating microRNAs in Breast Milk and Their Potential Impact on the Infant. Nutrients 2020; 12:nu12103066. [PMID: 33049923 PMCID: PMC7601398 DOI: 10.3390/nu12103066] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/27/2020] [Accepted: 10/01/2020] [Indexed: 02/06/2023] Open
Abstract
MicroRNAs (MiRNAs) are small RNA molecules that can exert regulatory functions in gene expression. MiRNAs have been identified in diverse tissues and biological fluids, both in the context of health and disease. Breastfeeding has been widely recognized for its superior nutritional benefits; however, a number of bioactive compounds have been found to transcend these well-documented nutritional contributions. Breast milk was identified as a rich source of miRNAs. There has been increasing interest about their potential ability to transfer to the offspring as well as what their specific involvement is within the benefits of breast milk in the infant. In comparison to breast milk, formula milk lacks many of the benefits of breastfeeding, which is thought to be a result of the absence of some of these bioactive compounds. In recent years, the miRNA profile of breast milk has been widely studied, along with the possible transfer mechanisms throughout the infant’s digestive tract and the role of miRNA-modulated genes and their potential protective and regulatory functions. Nonetheless, to date, the current evidence is not consistent, as many methodological limitations have been identified; hence, discrepancies exits about the biological functions of miRNAs. Further research is needed to provide thorough knowledge in this field.
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12
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Delfosse V, Bourguet W, Drin G. Structural and Functional Specialization of OSBP-Related Proteins. ACTA ACUST UNITED AC 2020. [DOI: 10.1177/2515256420946627] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Lipids are precisely distributed in the eukaryotic cell where they help to define organelle identity and function, in addition to their structural role. Once synthesized, many lipids must be delivered to other compartments by non-vesicular routes, a process that is undertaken by proteins called Lipid Transfer Proteins (LTPs). OSBP and the closely-related ORP and Osh proteins constitute a major, evolutionarily conserved family of LTPs in eukaryotes. Most of these target one or more subcellular regions, and membrane contact sites in particular, where two organelle membranes are in close proximity. It was initially thought that such proteins were strictly dedicated to sterol sensing or transport. However, over the last decade, numerous studies have revealed that these proteins have many more functions, and we have expanded our understanding of their mechanisms. In particular, many of them are lipid exchangers that exploit PI(4)P or possibly other phosphoinositide gradients to directionally transfer sterol or PS between two compartments. Importantly, these transfer activities are tightly coupled to processes such as lipid metabolism, cellular signalling and vesicular trafficking. This review describes the molecular architecture of OSBP/ORP/Osh proteins, showing how their specific structural features and internal configurations impart unique cellular functions.
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Affiliation(s)
- Vanessa Delfosse
- Centre de Biochimie Structurale, Inserm, CNRS, Univ Montpellier, Montpellier, France
| | - William Bourguet
- Centre de Biochimie Structurale, Inserm, CNRS, Univ Montpellier, Montpellier, France
| | - Guillaume Drin
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d’Azur, Valbonne, France
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Upregulation of OSBPL3 by HIF1A promotes colorectal cancer progression through activation of RAS signaling pathway. Cell Death Dis 2020; 11:571. [PMID: 32709922 PMCID: PMC7381633 DOI: 10.1038/s41419-020-02793-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 07/07/2020] [Accepted: 07/13/2020] [Indexed: 12/11/2022]
Abstract
Oxysterol-binding protein like protein 3 (OSBPL3) has been shown involving in the development of several human cancers. However, the relationship between OSBPL3 and colorectal cancer (CRC), particularly the role of OSBPL3 in the proliferation, invasion and metastasis of CRC remains unclear. In this study, we investigated the role of OSBPL3 in CRC and found that its expression was significantly higher in CRC tissues than that in normal tissues. In addition, high expression of OSBPL3 was closely related to poor differentiation, advanced TNM stage and poor prognosis of CRC. Further experiments showed that over-expression of OSBPL3 promoted the proliferation, invasion and metastasis of CRC in vitro and in vivo models. Moreover, we revealed that OSBPL3 promoted CRC progression through activation of RAS signaling pathway. Furthermore, we demonstrated that hypoxia induced factor 1 (HIF-1A) can regulate the expression of OSBPL3 via binding to the hypoxia response element (HRE) in the promoter of OSBPL3. In summary, Upregulation of OSBPL3 by HIF1A promotes colorectal cancer progression through activation of RAS signaling pathway. This novel mechanism provides a comprehensive understanding of both OSBPL3 and the RAS signaling pathway in the progression of CRC and indicates that the HIF1A–OSBPL3–RAS axis is a potential target for early therapeutic intervention in CRC progression.
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14
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Lipp NF, Ikhlef S, Milanini J, Drin G. Lipid Exchangers: Cellular Functions and Mechanistic Links With Phosphoinositide Metabolism. Front Cell Dev Biol 2020; 8:663. [PMID: 32793602 PMCID: PMC7385082 DOI: 10.3389/fcell.2020.00663] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/01/2020] [Indexed: 12/28/2022] Open
Abstract
Lipids are amphiphilic molecules that self-assemble to form biological membranes. Thousands of lipid species coexist in the cell and, once combined, define organelle identity. Due to recent progress in lipidomic analysis, we now know how lipid composition is finely tuned in different subcellular regions. Along with lipid synthesis, remodeling and flip-flop, lipid transfer is one of the active processes that regulates this intracellular lipid distribution. It is mediated by Lipid Transfer Proteins (LTPs) that precisely move certain lipid species across the cytosol and between the organelles. A particular subset of LTPs from three families (Sec14, PITP, OSBP/ORP/Osh) act as lipid exchangers. A striking feature of these exchangers is that they use phosphatidylinositol or phosphoinositides (PIPs) as a lipid ligand and thereby have specific links with PIP metabolism and are thus able to both control the lipid composition of cellular membranes and their signaling capacity. As a result, they play pivotal roles in cellular processes such as vesicular trafficking and signal transduction at the plasma membrane. Recent data have shown that some PIPs are used as energy by lipid exchangers to generate lipid gradients between organelles. Here we describe the importance of lipid counter-exchange in the cell, its structural basis, and presumed links with pathologies.
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Affiliation(s)
- Nicolas-Frédéric Lipp
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, Université Côte d'Azur, Valbonne, France
| | - Souade Ikhlef
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, Université Côte d'Azur, Valbonne, France
| | - Julie Milanini
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, Université Côte d'Azur, Valbonne, France
| | - Guillaume Drin
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, Université Côte d'Azur, Valbonne, France
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15
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ORP5 and ORP8: Sterol Sensors and Phospholipid Transfer Proteins at Membrane Contact Sites? Biomolecules 2020; 10:biom10060928. [PMID: 32570981 PMCID: PMC7356933 DOI: 10.3390/biom10060928] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/13/2020] [Accepted: 06/16/2020] [Indexed: 02/07/2023] Open
Abstract
Oxysterol binding related proteins 5 and 8 (ORP5 and ORP8) are two close homologs of the larger oxysterol binding protein (OSBP) family of sterol sensors and lipid transfer proteins (LTP). Early studies indicated these transmembrane proteins, anchored to the endoplasmic reticulum (ER), bound and sensed cholesterol and oxysterols. They were identified as important for diverse cellular functions including sterol homeostasis, vesicular trafficking, proliferation and migration. In addition, they were implicated in lipid-related diseases such as atherosclerosis and diabetes, but also cancer, although their mechanisms of action remained poorly understood. Then, alongside the increasing recognition that membrane contact sites (MCS) serve as hubs for non-vesicular lipid transfer, added to their structural similarity to other LTPs, came discoveries showing that ORP5 and 8 were in fact phospholipid transfer proteins that rather sense and exchange phosphatidylserine (PS) for phosphoinositides, including phosphatidylinositol-4-phosphate (PI(4)P) and potentially phosphatidylinositol-(4,5)-bisphosphate (PI(4,5)P2). Evidence now points to their action at MCS between the ER and various organelles including the plasma membrane, lysosomes, mitochondria, and lipid droplets. Dissecting exactly how this unexpected phospholipid transfer function connects with sterol regulation in health or disease remains a challenge for future studies.
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16
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Peng H, Yan Z, Zeng X, Zhang S, Jiang H, Huang H, Zhuo H. Serum and tissue proteomic signatures of patients with hepatocellular carcinoma using 2‑D gel electrophoresis. Mol Med Rep 2019; 20:1025-1038. [PMID: 31173207 PMCID: PMC6625405 DOI: 10.3892/mmr.2019.10311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 04/24/2019] [Indexed: 12/23/2022] Open
Abstract
Hepatocellular carcinoma (HCC) accounts for ~85% of primary liver cancer cases and is a leading cause of mortality worldwide. Effective early diagnosis is difficult for HCC; however, effective biomarkers may be beneficial for diagnosis. In the current study, serum samples, and HCC and adjacent tissue samples were obtained from patients with HCC for the detection of biomarkers using 2-D gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-time of flight (TOF)/TOF mass spectrometry. The crude serum samples did not need to be prepared for removal of high abundance proteins. The mRNA expression levels of HCC-associated proteins were detected in tissues using reverse transcription-quantitative PCR. Statistical analysis and database matching were used to identify the differentially expressed proteins detected in the serum and tissue groups. Immunohistochemistry (IHC) was performed to detect the expression of significant proteins in HCC and adjacent tissues. The results revealed ~800 protein spots on a 2-DE gel that were detected in serum samples, and 1,200 spots were identified in the tissue samples. The protein and mRNA expression levels of oxysterol binding protein-like 11 (OSBPL11) in HCC serum and tissue samples were consistent. Pathway analysis demonstrated that members of the apolipoprotein family, particularly apolipoprotein E (APOE), and RAS family members were closely associated in HCC, either directly or via ferratin heavy polypeptide 1. IHC results demonstrated that the APOE protein serves an important role in liver cancer development. The lysis buffer used in the current study was effective for serum protein separation in 2-DE sample preparation. In addition, the present study revealed that downregulated OSBPL11 may be a potential indicator for HCC, and the apolipoprotein family, particularly APOE, and the RAS family may cooperatively serve an important role.
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Affiliation(s)
- Huifang Peng
- Department of Endocrinology, The First Affiliated Hospital and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, Henan 471000, P.R. China
| | - Zhijian Yan
- Department of Urology, The Affiliated Zhongshan Hospital, Xiamen University, Xiamen, Fujian 361004, P.R. China
| | - Xinhua Zeng
- State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen, Fujian 361004, P.R. China
| | - Sheng Zhang
- Fujian Provincial Key Laboratory of Chronic Liver Disease and Hepatocellular Carcinoma, The Affiliated Zhongshan Hospital, Xiamen University, Xiamen, Fujian 361004, P.R. China
| | - Hongwei Jiang
- Department of Endocrinology, The First Affiliated Hospital and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, Henan 471000, P.R. China
| | - Heqing Huang
- State Key Laboratory of Stress Cell Biology, School of Life Science, Xiamen University, Xiamen, Fujian 361004, P.R. China
| | - Huiqin Zhuo
- Department of Gastrointestinal Surgery, Zhongshan Hospital, Xiamen University, Xiamen, Fujian 361004, P.R. China
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Luo J, Jiang LY, Yang H, Song BL. Intracellular Cholesterol Transport by Sterol Transfer Proteins at Membrane Contact Sites. Trends Biochem Sci 2019; 44:273-292. [DOI: 10.1016/j.tibs.2018.10.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/06/2018] [Accepted: 10/10/2018] [Indexed: 12/20/2022]
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18
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Regulation of targeting determinants in interorganelle communication. Curr Opin Cell Biol 2019; 57:106-114. [PMID: 30807956 DOI: 10.1016/j.ceb.2018.12.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 12/27/2018] [Accepted: 12/28/2018] [Indexed: 01/02/2023]
Abstract
The field of interorganelle communication is now established as a major aspect of intracellular organisation, with a profusion of material and signals exchanged between organelles. One way to address interorganelle communication is to study the interactions of the proteins involved, particularly targeting interactions, which are a key way to regulate activity. While most peripheral membrane proteins have single determinants for membrane targeting, proteins involved in interorganelle communication have more than one such determinant, sometimes as many as four, as in Vps13. Here we review the targeting determinants, showing how they can be relatively hard to find, how they are regulated, and how proteins integrate information from multiple targeting determinants.
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19
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Manik MK, Yang H, Tong J, Im YJ. Structure of Yeast OSBP-Related Protein Osh1 Reveals Key Determinants for Lipid Transport and Protein Targeting at the Nucleus-Vacuole Junction. Structure 2017; 25:617-629.e3. [PMID: 28319008 DOI: 10.1016/j.str.2017.02.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 01/19/2017] [Accepted: 02/22/2017] [Indexed: 01/25/2023]
Abstract
Yeast Osh1 belongs to the oxysterol-binding protein (OSBP) family of proteins and contains multiple targeting modules optimized for lipid transport at the nucleus-vacuole junction (NVJ). The key determinants for NVJ targeting and the role of Osh1 at NVJs have remained elusive because of unknown lipid specificities. In this study, we determined the structures of the ankyrin repeat domain (ANK), and OSBP-related domain (ORD) of Osh1, in complex with Nvj1 and ergosterol, respectively. The Osh1 ANK forms a unique bi-lobed structure that recognizes a cytosolic helical segment of Nvj1. We discovered that Osh1 ORD binds ergosterol and phosphatidylinositol 4-phosphate PI(4)P in a competitive manner, suggesting counter-transport function of the two lipids. Ergosterol is bound to the hydrophobic pocket in a head-down orientation, and the structure of the PI(4)P-binding site in Osh1 is well conserved. Our results suggest that Osh1 performs non-vesicular transport of ergosterol and PI(4)P at the NVJ.
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Affiliation(s)
| | - Huiseon Yang
- College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Junsen Tong
- College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Young Jun Im
- College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea.
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20
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Dong R, Saheki Y, Swarup S, Lucast L, Harper JW, De Camilli P. Endosome-ER Contacts Control Actin Nucleation and Retromer Function through VAP-Dependent Regulation of PI4P. Cell 2017; 166:408-423. [PMID: 27419871 DOI: 10.1016/j.cell.2016.06.037] [Citation(s) in RCA: 268] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 04/15/2016] [Accepted: 06/17/2016] [Indexed: 12/18/2022]
Abstract
VAP (VAPA and VAPB) is an evolutionarily conserved endoplasmic reticulum (ER)-anchored protein that helps generate tethers between the ER and other membranes through which lipids are exchanged across adjacent bilayers. Here, we report that by regulating PI4P levels on endosomes, VAP affects WASH-dependent actin nucleation on these organelles and the function of the retromer, a protein coat responsible for endosome-to-Golgi traffic. VAP is recruited to retromer budding sites on endosomes via an interaction with the retromer SNX2 subunit. Cells lacking VAP accumulate high levels of PI4P, actin comets, and trans-Golgi proteins on endosomes. Such defects are mimicked by downregulation of OSBP, a VAP interactor and PI4P transporter that participates in VAP-dependent ER-endosomes tethers. These results reveal a role of PI4P in retromer-/WASH-dependent budding from endosomes. Collectively, our data show how the ER can control budding dynamics and association with the cytoskeleton of another membrane by direct contacts leading to bilayer lipid modifications.
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Affiliation(s)
- Rui Dong
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA; Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Yasunori Saheki
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA; Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Sharan Swarup
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Louise Lucast
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA; Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510, USA
| | - J Wade Harper
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA; Kavli Institute for Neurosciences, Yale University School of Medicine, New Haven, CT 06510, USA; Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510, USA.
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21
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Lipid transfer proteins do their thing anchored at membrane contact sites… but what is their thing? Biochem Soc Trans 2016; 44:517-27. [PMID: 27068964 DOI: 10.1042/bst20150275] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Indexed: 02/06/2023]
Abstract
Membrane contact sites are structures where two organelles come close together to regulate flow of material and information between them. One type of inter-organelle communication is lipid exchange, which must occur for membrane maintenance and in response to environmental and cellular stimuli. Soluble lipid transfer proteins have been extensively studied, but additional families of transfer proteins have been identified that are anchored into membranes by transmembrane helices so that they cannot diffuse through the cytosol to deliver lipids. If such proteins target membrane contact sites they may be major players in lipid metabolism. The eukaryotic family of so-called Lipid transfer proteins Anchored at Membrane contact sites (LAMs) all contain both a sterol-specific lipid transfer domain in the StARkin superfamily (related to StART/Bet_v1), and one or more transmembrane helices anchoring them in the endoplasmic reticulum (ER), making them interesting subjects for study in relation to sterol metabolism. They target a variety of membrane contact sites, including newly described contacts between organelles that were already known to make contact by other means. Lam1-4p target punctate ER-plasma membrane contacts. Lam5p and Lam6p target multiple contacts including a new category: vacuolar non-NVJ cytoplasmic ER (VancE) contacts. These developments confirm previous observations on tubular lipid-binding proteins (TULIPs) that established the importance of membrane anchored proteins for lipid traffic. However, the question remaining to be solved is the most difficult of all: are LAMs transporters, or alternately are they regulators that affect traffic more indirectly?
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22
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Escajadillo T, Wang H, Li L, Li D, Sewer MB. Oxysterol-related-binding-protein related Protein-2 (ORP2) regulates cortisol biosynthesis and cholesterol homeostasis. Mol Cell Endocrinol 2016; 427:73-85. [PMID: 26992564 PMCID: PMC4833515 DOI: 10.1016/j.mce.2016.03.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 03/04/2016] [Accepted: 03/04/2016] [Indexed: 12/30/2022]
Abstract
Oxysterol binding protein-related protein 2 (ORP2) is a lipid binding protein that has been implicated in various cellular processes, including lipid sensing, cholesterol efflux, and endocytosis. We recently identified ORP2 as a member of a protein complex that regulates glucocorticoid biosynthesis. Herein, we examine the effect of silencing ORP2 on adrenocortical function and show that the ORP2 knockdown cells exhibit reduced amounts of multiple steroid metabolites, including progesterone, 11-deoxycortisol, and cortisol, but have increased concentrations of androgens, and estrogens. Moreover, silencing ORP2 suppresses the expression of most proteins required for cortisol production and reduces the expression of steroidogenic factor 1 (SF1). ORP2 silencing also increases cellular cholesterol, concomitant with decreased amounts of 22-hydroxycholesterol and 7-ketocholesterol, two molecules that have been shown to bind to ORP2. Further, we show that ORP2 binds to liver X receptor (LXR) and is required for nuclear LXR expression. LXR and ORP2 are recruited to the CYP11B1 promoter in response to cAMP signaling. Additionally, ORP2 is required for the expression of other LXR target genes, including ABCA1 and the LDL receptor (LDLR). In summary, we establish a novel role for ORP2 in regulating steroidogenic capacity and cholesterol homeostasis in the adrenal cortex.
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Affiliation(s)
- Tamara Escajadillo
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA.
| | - Hongxia Wang
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Linda Li
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Donghui Li
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Marion B Sewer
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
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23
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Olkkonen VM. OSBP-Related Protein Family in Lipid Transport Over Membrane Contact Sites. Lipid Insights 2015; 8:1-9. [PMID: 26715851 PMCID: PMC4685180 DOI: 10.4137/lpi.s31726] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 09/03/2015] [Accepted: 09/06/2015] [Indexed: 12/12/2022] Open
Abstract
Increasing evidence suggests that oxysterol-binding protein-related proteins (ORPs) localize at membrane contact sites, which are high-capacity platforms for inter-organelle exchange of small molecules and information. ORPs can simultaneously associate with the two apposed membranes and transfer lipids across the interbilayer gap. Oxysterol-binding protein moves cholesterol from the endoplasmic reticulum to trans-Golgi, driven by the retrograde transport of phosphatidylinositol-4-phosphate (PI4P). Analogously, yeast Osh6p mediates the transport of phosphatidylserine from the endoplasmic reticulum to the plasma membrane in exchange for PI4P, and ORP5 and -8 are suggested to execute similar functions in mammalian cells. ORPs may share the capacity to bind PI4P within their ligand-binding domain, prompting the hypothesis that bidirectional transport of a phosphoinositide and another lipid may be a common theme among the protein family. This model, however, needs more experimental support and does not exclude a function of ORPs in lipid signaling.
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Affiliation(s)
- Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, Helsinki, Finland. ; Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland
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24
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MicroRNAs in Breastmilk and the Lactating Breast: Potential Immunoprotectors and Developmental Regulators for the Infant and the Mother. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:13981-4020. [PMID: 26529003 PMCID: PMC4661628 DOI: 10.3390/ijerph121113981] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 10/21/2015] [Accepted: 10/27/2015] [Indexed: 12/12/2022]
Abstract
Human milk (HM) is the optimal source of nutrition, protection and developmental programming for infants. It is species-specific and consists of various bioactive components, including microRNAs, small non-coding RNAs regulating gene expression at the post-transcriptional level. microRNAs are both intra- and extra-cellular and are present in body fluids of humans and animals. Of these body fluids, HM appears to be one of the richest sources of microRNA, which are highly conserved in its different fractions, with milk cells containing more microRNAs than milk lipids, followed by skim milk. Potential effects of exogenous food-derived microRNAs on gene expression have been demonstrated, together with the stability of milk-derived microRNAs in the gastrointestinal tract. Taken together, these strongly support the notion that milk microRNAs enter the systemic circulation of the HM fed infant and exert tissue-specific immunoprotective and developmental functions. This has initiated intensive research on the origin, fate and functional significance of milk microRNAs. Importantly, recent studies have provided evidence of endogenous synthesis of HM microRNA within the human lactating mammary epithelium. These findings will now form the basis for investigations of the role of microRNA in the epigenetic control of normal and aberrant mammary development, and particularly lactation performance.
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Gatta AT, Wong LH, Sere YY, Calderón-Noreña DM, Cockcroft S, Menon AK, Levine TP. A new family of StART domain proteins at membrane contact sites has a role in ER-PM sterol transport. eLife 2015; 4. [PMID: 26001273 PMCID: PMC4463742 DOI: 10.7554/elife.07253] [Citation(s) in RCA: 191] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/20/2015] [Indexed: 12/18/2022] Open
Abstract
Sterol traffic between the endoplasmic reticulum (ER) and plasma membrane (PM) is a fundamental cellular process that occurs by a poorly understood non-vesicular mechanism. We identified a novel, evolutionarily diverse family of ER membrane proteins with StART-like lipid transfer domains and studied them in yeast. StART-like domains from Ysp2p and its paralog Lam4p specifically bind sterols, and Ysp2p, Lam4p and their homologs Ysp1p and Sip3p target punctate ER-PM contact sites distinct from those occupied by known ER-PM tethers. The activity of Ysp2p, reflected in amphotericin-sensitivity assays, requires its second StART-like domain to be positioned so that it can reach across ER-PM contacts. Absence of Ysp2p, Ysp1p or Sip3p reduces the rate at which exogenously supplied sterols traffic from the PM to the ER. Our data suggest that these StART-like proteins act in trans to mediate a step in sterol exchange between the PM and ER. DOI:http://dx.doi.org/10.7554/eLife.07253.001 Membranes are crucial structures for cells that are made primarily of fat molecules. The most important membrane is the external one that surrounds cells and keeps the outside world out and cellular contents in. The single most common fat component in the external membrane is cholesterol, which makes the membrane rigid and better able to withstand the outside world. So even though excess cholesterol contributes to diseases such as heart disease, stroke and Alzheimer's, the external membrane of every cell needs about a billion cholesterol molecules for its normal function. But how do cells manage the traffic of these molecules to their destination? It is known that when external membranes are short of cholesterol they make it at a different cellular location. There is an internal network—called the endoplasmic reticulum—that spreads just about everywhere throughout the cell. This network is where fats like cholesterol are made when the cell has not got enough, and where they are converted into an inert form when the cell has too much. What is not known is how cholesterol moves to and fro between this network and the external membrane. One theory is that cholesterol and other fats move only where the internal network comes into close contact with the external membrane, without quite touching. This theory comes in part from the finding that many of the proteins found in the narrow gaps between the internal network and the external membrane are capable of transferring fats across the gap. However, one of the missing supports for this theory is that no protein that transfers cholesterol across this gap has been found. Gatta, Wong, Sere et al. used computational tools to scan the database of known proteins for those that might be able to transfer cholesterol, and found a new family of fat transfer proteins. Further experiments showed that these proteins only bind to cholesterol out of all the fats. Next, Gatta, Wong, Sere et al. studied what the proteins do in cells, but instead of looking at the proteins in human cells they studied the related proteins in yeast. This is because the details of both the traffic of cholesterol and contacts between the internal network and the external membrane are in many respects understood better in yeast than in human cells. Gatta, Wong, Sere et al. found the cholesterol transfer proteins were embedded in regions where the internal network was in close contact with the external membrane. Also, in cells that lacked these proteins, cholesterol added to the external membrane had difficulty transferring to the internal network. These results together suggest that the newly identified lipid transfer proteins exchange lipids between the plasma membrane and endoplasmic reticulum at membrane contact sites. Further research is required to understand in detail how these proteins work. DOI:http://dx.doi.org/10.7554/eLife.07253.002
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Affiliation(s)
- Alberto T Gatta
- Department of Cell Biology, UCL Institute of Ophthalmology, London, United Kingdom
| | - Louise H Wong
- Department of Cell Biology, UCL Institute of Ophthalmology, London, United Kingdom
| | - Yves Y Sere
- Department of Biochemistry, Weill Cornell Medical College, New York, United States
| | | | - Shamshad Cockcroft
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Anant K Menon
- Department of Biochemistry, Weill Cornell Medical College, New York, United States
| | - Tim P Levine
- Department of Cell Biology, UCL Institute of Ophthalmology, London, United Kingdom
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Weber-Boyvat M, Kentala H, Peränen J, Olkkonen VM. Ligand-dependent localization and function of ORP-VAP complexes at membrane contact sites. Cell Mol Life Sci 2015; 72:1967-87. [PMID: 25420878 PMCID: PMC11114005 DOI: 10.1007/s00018-014-1786-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 10/17/2014] [Accepted: 11/17/2014] [Indexed: 01/08/2023]
Abstract
Oxysterol-binding protein/OSBP-related proteins (ORPs) constitute a conserved family of sterol/phospholipid-binding proteins with lipid transporter or sensor functions. We investigated the spatial occurrence and regulation of the interactions of human OSBP/ORPs or the S. cerevisiae orthologs, the Osh (OSBP homolog) proteins, with their endoplasmic reticulum (ER) anchors, the VAMP-associated proteins (VAPs), by employing bimolecular fluorescence complementation and pull-down set-ups. The ORP-VAP interactions localize frequently at distinct subcellular sites, shown in several cases to represent membrane contact sites (MCSs). Using established ORP ligand-binding domain mutants and pull-down assays with recombinant proteins, we show that ORP liganding regulates the ORP-VAP association, alters the subcellular targeting of ORP-VAP complexes, or modifies organelle morphology. There is distinct protein specificity in the effects of the mutants on subcellular targeting of ORP-VAP complexes. We provide evidence that complexes of human ORP2 and VAPs at ER-lipid droplet interfaces regulate the hydrolysis of triglycerides and lipid droplet turnover. The data suggest evolutionarily conserved, complex ligand-dependent functions of ORP-VAP complexes at MCSs, with implications for cellular lipid homeostasis and signaling.
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Affiliation(s)
- Marion Weber-Boyvat
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, Tukholmankatu 8, 00290 Helsinki, Finland
| | - Henriikka Kentala
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, Tukholmankatu 8, 00290 Helsinki, Finland
| | - Johan Peränen
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Vesa M. Olkkonen
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, Tukholmankatu 8, 00290 Helsinki, Finland
- Institute of Biomedicine, Anatomy, University of Helsinki, 00014 Helsinki, Finland
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Bang S, Kwon H, Hwang HS, Park KD, Kim SU, Bahn YS. 9-O-butyl-13-(4-isopropylbenzyl)berberine, KR-72, is a potent antifungal agent that inhibits the growth of Cryptococcus neoformans by regulating gene expression. PLoS One 2014; 9:e109863. [PMID: 25302492 PMCID: PMC4193857 DOI: 10.1371/journal.pone.0109863] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 09/02/2014] [Indexed: 11/28/2022] Open
Abstract
In this study we explored the mode of action of KR-72, a 9-O-butyl-13-(4-isopropylbenzyl)berberine derivative previously shown to exhibit potent antifungal activity against a variety of human fungal pathogens. The DNA microarray data revealed that KR-72 treatment significantly changed the transcription profiles of C. neoformans, affecting the expression of more than 2,000 genes. Genes involved in translation and transcription were mostly upregulated, whereas those involved in the cytoskeleton, intracellular trafficking, and lipid metabolism were downregulated. KR-72 also exhibited a strong synergistic effect with the antifungal agent FK506. KR-72 treatment regulated the expression of several essential genes, including ECM16, NOP14, HSP10 and MGE1, which are required for C. neoformans growth. The KR-72-mediated induction of MGE1 also likely reduced the viability of C. neoformans by impairing cell cycle or the DNA repair system. In conclusion, KR-72 showed antifungal activity by modulating diverse biological processes through a mode of action distinct from those of clinically available antifungal drugs such as polyene and azole drugs.
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Affiliation(s)
- Soohyun Bang
- Department of Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Hyojeong Kwon
- Department of Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Hyun Sook Hwang
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology, Seoul, Republic of Korea
| | - Ki Duk Park
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology, Seoul, Republic of Korea
| | - Sung Uk Kim
- Industrial Bio-materials Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Yong-Sun Bahn
- Department of Biotechnology, Yonsei University, Seoul, Republic of Korea
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Aponte JR, Vasicek L, Swaminathan J, Xu H, Koag MC, Lee S, Brodbelt JS. Streamlining bottom-up protein identification based on selective ultraviolet photodissociation (UVPD) of chromophore-tagged histidine- and tyrosine-containing peptides. Anal Chem 2014; 86:6237-44. [PMID: 24897623 DOI: 10.1021/ac403654m] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We report a fast and highly efficient diazonium reaction that couples a nitroazobenzene chromophore to tyrosine and histidine residues, thus endowing peptides with high photoabsorption cross sections at 351 nm in the gas phase. Only the tagged peptides undergo ultraviolet photodissociation (UVPD) at 351 nm, as demonstrated for several Tyr- and His-containing peptides from protein digests. Additional selectivity is achieved by the integration of the UVPD-MS method with an in silico database search restricted to Tyr- and His-containing peptides. A modified MassMatrix algorithm condenses analysis by filtering the input database file to include Tyr/His-containing peptides only, thus reducing the search space and increasing confidence. In summary, derivatization of specific amino acid residues in conjunction with selective activation of the derivatized peptides provides a streamlined approach to shotgun proteomics.
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Affiliation(s)
- Julia R Aponte
- Department of Chemistry, The University of Texas at Austin , 1 University Station A5300, Austin, Texas 78712, United States
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A vertebrate model for the study of lipid binding/transfer protein function: Conservation of OSBP-related proteins between zebrafish and human. Biochem Biophys Res Commun 2014; 446:675-80. [DOI: 10.1016/j.bbrc.2013.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 12/02/2013] [Indexed: 01/12/2023]
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OSBP-related proteins: liganding by glycerophospholipids opens new insight into their function. Molecules 2013; 18:13666-79. [PMID: 24196413 PMCID: PMC6270239 DOI: 10.3390/molecules181113666] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 11/01/2013] [Accepted: 11/01/2013] [Indexed: 12/12/2022] Open
Abstract
Oxysterol-binding protein (OSBP) and its homologs designated OSBP-related (ORP) or OSBP-like (OSBPL) proteins constitute a conserved family of lipid binding/transfer proteins (LTP) in eukaryotes. The mechanisms of ORP function have remained incompletely understood, but they have been implicated as intracellular sterol sensors or transporters. A number of studies have provided evidence for the roles of ORPs at membrane contact sites (MCS), where endoplasmic reticulum is closely apposed with other organelle limiting membranes. ORPs are postulated to either transport sterols over MCSs or control the activity of enzymatic effectors or assembly of protein complexes with functions in signaling and lipid metabolism. Studies of yeast Saccharomyces cerevisiae ORPs Osh4p, Osh3p, Osh6p and Osh7p have revealed that ORPs do not exclusively bind sterols within their OSBP-related ligand-binding domain (ORD): The Osh4p ORD accommodates either sterols or phosphatidylinositol-4-phosphate (PI4P), and the Osh3p ORD was shown to specifically bind PI4P, the binding cavity being too narrow for a sterol to fit in. Most recently, Osh6p and Osh7p were demonstrated to show specific affinity for phosphatidylserine (PS), and to play a role in the intracellular transport of this glycerophospholipid; Additionally, two mammalian ORPs were shown to bind PS. Thus, the term frequently used for ORPs/OSBPLs, oxysterol-binding proteins, is a misnomer. While a number of ORPs bind oxysterols or cholesterol, other family members appear to interact with phospholipid ligands to regulate lipid fluxes, organelle lipid compositions and cell signaling. As a conclusion, ORPs are LTPs with a wide ligand spectrum and marked functional heterogeneity.
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Olkkonen VM, Li S. Oxysterol-binding proteins: Sterol and phosphoinositide sensors coordinating transport, signaling and metabolism. Prog Lipid Res 2013; 52:529-38. [DOI: 10.1016/j.plipres.2013.06.004] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 06/15/2013] [Accepted: 06/22/2013] [Indexed: 01/27/2023]
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32
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Koag MC, Cheun Y, Kou Y, Ouzon-Shubeita H, Min K, Monzingo AF, Lee S. Synthesis and structure of 16,22-diketocholesterol bound to oxysterol-binding protein Osh4. Steroids 2013; 78:938-44. [PMID: 23756172 DOI: 10.1016/j.steroids.2013.05.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 05/24/2013] [Accepted: 05/28/2013] [Indexed: 11/21/2022]
Abstract
We have synthesized 16,22-diketocholesterol, a novel ligand for oxysterol-binding protein Osh4, and determined X-ray structure of the diketocholesterol in complex with Osh4. The X-ray structure shows that α7 helix of Osh4 assumes open conformation while the rest of Osh4, closed conformation, implying this diketocholesterol-bound Osh4 structure may represent a structural intermediate between the two conformations.
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Affiliation(s)
- Myong Chul Koag
- Division of Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, USA
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33
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Short AD, Boag A, Catchpole B, Kennedy LJ, Massey J, Rothwell S, Husebye E, Ollier B. A candidate gene analysis of canine hypoadrenocorticism in 3 dog breeds. J Hered 2013; 104:807-20. [PMID: 23997205 DOI: 10.1093/jhered/est051] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Canine hypoadrenocorticism is believed to be an immune-related condition. It is rare in the overall dog population but shows a breed-related predisposition with Standard poodles and Portuguese water dogs having a greater prevalence of the condition. It shares many similarities with human primary adrenal insufficiency and is believed to be a naturally occurring, spontaneous model for the human condition. Short haplotype blocks and low levels of linkage disequilibrium in the human genome mean that the identification of genetic contributors to the condition requires large sample numbers. Pedigree dogs have high linkage disequilibrium and long haplotypes within a breed, increasing the potential of identifying novel genes that contribute to canine genetic disease. We investigated 222 SNPs from 42 genes that have been associated or may be implicated in human Addison's disease. We conducted case-control analyses in 3 pedigree dog breeds (Labrador retriever: affected n = 30, unaffected = 76; Cocker Spaniel: affected n = 19, unaffected = 53; Springer spaniel: affected n = 26, unaffected = 46) and identified 8 associated alleles in genes COL4A4, OSBPL9, CTLA4, PTPN22, and STXBP5 in 3 pedigree breeds. Association with immune response genes PTPN22 and CTLA4 in certain breeds suggests an underlying immunopathogenesis of the disease. These results suggest that canine hypoadrenocorticism could be a useful model for studying comparative genetics relevant to human Addison's disease.
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Affiliation(s)
- Andrea D Short
- the Centre for Integrated Genomic Medical Research, The University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, UK
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34
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Sewer MB, Li D. Regulation of adrenocortical steroid hormone production by RhoA-diaphanous 1 signaling and the cytoskeleton. Mol Cell Endocrinol 2013; 371. [PMID: 23186810 PMCID: PMC3926866 DOI: 10.1016/j.mce.2012.11.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The production of glucocorticoids and aldosterone in the adrenal cortex is regulated at multiple levels. Biosynthesis of these hormones is initiated when cholesterol, the substrate, enters the inner mitochondrial membrane for conversion to pregnenolone. Unlike most metabolic pathways, the biosynthesis of adrenocortical steroid hormones is unique because some of the enzymes are localized in mitochondria and others in the endoplasmic reticulum (ER). Although much is known about the factors that control the transcription and activities of the proteins that are required for steroid hormone production, the parameters that govern the exchange of substrates between the ER and mitochondria are less well understood. This short review summarizes studies that have begun to provide insight into the role of the cytoskeleton, mitochondrial transport, and the physical interaction of the ER and mitochondria in the production of adrenocortical steroid hormones.
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Affiliation(s)
- Marion B Sewer
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093-0704, USA.
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35
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de Weille J, Fabre C, Bakalara N. Oxysterols in cancer cell proliferation and death. Biochem Pharmacol 2013; 86:154-60. [PMID: 23500545 DOI: 10.1016/j.bcp.2013.02.029] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 02/27/2013] [Accepted: 02/27/2013] [Indexed: 12/21/2022]
Abstract
Oxysterols have been shown to interfere with proliferation and cause the death of many cancer cell types, such as leukaemia, glioblastoma, colon, breast and prostate cancer cells, while they have little or no effect on senescent cells. The mechanisms by which oxysterols may influence proliferation are manifold: they control the transcription and the turnover of the key enzyme in cholesterol synthesis, 3-hydroxy-3-methylglutaryl CoA reductase, by binding to Insig-1, Insig-2 and liver X receptors. Oxysterols are thought to be generated in proportion to the rate of cholesterol synthesis. Although there is no consensus about the mechanism by which these oxysterols are generated in vivo, it clearly has to be ubiquitous. The 25- and the 27-cholesterol hydroxylases, present in almost all tissues, are possible candidates. Cholesterol uptake from lipoproteins, intracellular vesicle transport and lipid transfer are also modified by oxysterols. Oxysterols interfere with ERK, hedgehog and wnt pathways of proliferation and differentiation. When administered in vitro to cancer cell lines, oxysterols invariably both slow down proliferation and provoke cell death. Perhaps is it sufficient to stop proliferation of a cancer to provoke its eradication. Therefore, the two facets of oxysterol action that seem important for cancer treatment, cytostaticity and cytotoxicity, will be discussed.
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Affiliation(s)
- Jan de Weille
- Institut des Neurosciences de Montpellier, U1051 INSERM, 80 rue Augustin Fliche, 34295 Montpellier Cedex 05, France.
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36
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Weber-Boyvat M, Zhong W, Yan D, Olkkonen VM. Oxysterol-binding proteins: functions in cell regulation beyond lipid metabolism. Biochem Pharmacol 2013; 86:89-95. [PMID: 23428468 DOI: 10.1016/j.bcp.2013.02.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 12/12/2022]
Abstract
Oxysterol-binding (OSBP)-related proteins (ORPs) constitute a family of sterol and phosphoinositide binding/transfer proteins in eukaryotes from yeast to man. While their functions have mainly been addressed in cellular lipid metabolism or sterol transport, increasing evidence points to more versatile regulatory roles in a spectrum of cellular regimes. In fact ORPs do not appear to be robust controllers of lipid homeostasis. Several ORPs localize at membrane contacts sites (MCS), where endoplasmic reticulum (ER) is apposed with other organelle limiting membranes. Apparently, ORPs have the capacity to control the formation of MCS or activity of enzymatic machineries at these sites. Thereby, ORPs most likely affect organelle membrane lipid compositions, with impacts on signaling and vesicle transport, but also cellular lipid metabolism. Moreover, an increasing number of protein interaction partners of ORPs have been identified, connecting these proteins with various aspects of cell regulation. Small molecular anti-proliferative compounds, ORPphilins, were recently found to target two members of the ORP family, OSBP and ORP4, revealing an essential function of ORPs in cancer cell proliferation and survival. Further functions assigned for ORPs include regulation of extracellular signal regulated kinase (ERK) activity (OSBP), control of ER-late endosome MCS and late endosome motility (ORP1L), regulation of β1-integrin activity (ORP3), modulation of hepatocyte insulin signaling and macrophage migration (ORP8), as well as post-Golgi vesicle transport, phosphatidylinositol-4-phosphate and target of rapamycin complex 1 signaling and nitrogen sensing (Saccharomyces cerevisiae Osh4p). These and other recent observations shed light on the ORPs as integrators of lipid signals with an unforeseen variety of vital cellular processes.
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Affiliation(s)
- Marion Weber-Boyvat
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, FI-00290 Helsinki, Finland
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37
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Li D, Dammer EB, Lucki NC, Sewer MB. cAMP-stimulated phosphorylation of diaphanous 1 regulates protein stability and interaction with binding partners in adrenocortical cells. Mol Biol Cell 2013; 24:848-57. [PMID: 23325789 PMCID: PMC3596254 DOI: 10.1091/mbc.e12-08-0597] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
DIAPH1, the RhoA effector protein, forms a complex in adrenocortical cells and is phosphorylated by a cAMP/PKA-dependent pathway. Phosphorylation differentially modulates protein–protein interactions, regulates the stability of the protein, and facilitates sumoylation. Diaphanous homologue 1 (DIAPH1) is a Rho effector protein that coordinates cellular dynamics by regulating microfilament and microtubule function. We previously showed that DIAPH1 plays an integral role in regulating the production of cortisol by controlling the rate of mitochondrial movement, by which activation of the adrenocorticotropin (ACTH)/cAMP signaling pathway stimulates mitochondrial trafficking and promotes the interaction between RhoA and DIAPH1. In the present study we use mass spectrometry to identify DIAPH1 binding partners and find that DIAPH1 interacts with several proteins, including RhoA, dynamin-1, kinesin, β-tubulin, β-actin, oxysterol-binding protein (OSBP)–related protein 2 (ORP2), and ORP10. Moreover, DIAPH1 is phosphorylated in response to dibutyryl cAMP (Bt2cAMP) at Thr-759 via a pathway that requires extracellular signal-related kinase (ERK). Alanine substitution of Thr-759 renders DIAPH1 more stable and attenuates the interaction between DIAPH1 and kinesin, ORP2, and actin but has no effect on the ability of the protein to interact with RhoA or β-tubulin. Finally, overexpression of a DIAPH1 T759A mutant significantly decreases the rate of Bt2cAMP-stimulated mitochondrial movement. Taken together, our findings establish a key role for phosphorylation in regulating the stability and function of DIAPH1.
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Affiliation(s)
- Donghui Li
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093-0704, USA
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38
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Abstract
The Kes1 OSBP (oxysterol-binding protein) is a key regulator of membrane trafficking through the TGN (trans-Golgi network) and endosomal membranes. We demonstrated recently that Kes1 acts as a sterol-regulated rheostat for TGN/endosomal phosphatidylinositol 4-phosphate signalling. Kes1 utilizes its dual lipid-binding activities to integrate endosomal lipid metabolism with TORC1 (target of rapamycin complex 1)-dependent proliferative pathways and transcriptional control of nutrient signalling.
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39
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Mijaljica D, Prescott M, Devenish RJ. A late form of nucleophagy in Saccharomyces cerevisiae. PLoS One 2012; 7:e40013. [PMID: 22768199 PMCID: PMC3386919 DOI: 10.1371/journal.pone.0040013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 06/04/2012] [Indexed: 12/19/2022] Open
Abstract
Autophagy encompasses several processes by which cytosol and organelles can be delivered to the vacuole/lysosome for breakdown and recycling. We sought to investigate autophagy of the nucleus (nucleophagy) in the yeast Saccharomyces cerevisiae by employing genetically encoded fluorescent reporters. The use of such a nuclear reporter, n-Rosella, proved the basis of robust assays based on either following its accumulation (by confocal microscopy), or degradation (by immunoblotting), within the vacuole. We observed the delivery of n-Rosella to the vacuole only after prolonged periods of nitrogen starvation. Dual labeling of cells with Nvj1p-EYFP, a nuclear membrane reporter of piecemeal micronucleophagy of the nucleus (PMN), and the nucleoplasm-targeted NAB35-DsRed.T3 allowed us to detect PMN soon after the commencement of nitrogen starvation whilst delivery to the vacuole of the nucleoplasm reporter was observed only after prolonged periods of nitrogen starvation. This later delivery of nuclear components to the vacuole has been designated LN (late nucleophagy). Only a very few cells showed simultaneous accumulation of both reporters (Nvj1p-EYFP and NAB35-DsRed.T3) in the vacuole. We determined, therefore, that delivery of the two respective nuclear reporters to the vacuole is temporally and spatially separated. Furthermore, our data suggest that LN is mechanistically distinct from PMN because it can occur in nvj1Δ and vac8Δ cells, and does not require ATG11. Nevertheless, a subset of the components of the core macroautophagic machinery is required for LN as it is efficiently inhibited in null mutants of several autophagy-related genes (ATG) specifying such components. Moreover, the inhibition of LN in some mutants is accompanied by alterations in nuclear morphology.
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Affiliation(s)
- Dalibor Mijaljica
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Victoria, Australia
| | - Mark Prescott
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Victoria, Australia
| | - Rodney J. Devenish
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Victoria, Australia
- * E-mail:
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40
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Diverse roles of macrophages in atherosclerosis: from inflammatory biology to biomarker discovery. Mediators Inflamm 2012; 2012:693083. [PMID: 22577254 PMCID: PMC3337637 DOI: 10.1155/2012/693083] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 01/11/2012] [Indexed: 02/07/2023] Open
Abstract
Cardiovascular disease, a leading cause of mortality in developed countries, is mainly caused by atherosclerosis, a chronic inflammatory disease. Macrophages, which differentiate from monocytes that are recruited from the blood, account for the majority of leukocytes in atherosclerotic plaques. Apoptosis and the suppressed clearance of apoptotic macrophages (efferocytosis) are associated with vulnerable plaques that are prone to rupture, leading to thrombosis. Based on the central functions of macrophages in atherogenesis, cytokines, chemokines, enzymes, or microRNAs related to or produced by macrophages have become important clinical prognostic or diagnostic biomarkers. This paper discusses the impact of monocyte-derived macrophages in early atherogenesis and advanced disease. The role and possible future development of macrophage inflammatory biomarkers are also described.
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41
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Beh CT, McMaster CR, Kozminski KG, Menon AK. A detour for yeast oxysterol binding proteins. J Biol Chem 2012; 287:11481-8. [PMID: 22334669 DOI: 10.1074/jbc.r111.338400] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Oxysterol binding protein-related proteins, including the yeast proteins encoded by the OSH gene family (OSH1-OSH7), are implicated in the non-vesicular transfer of sterols between intracellular membranes and the plasma membrane. In light of recent studies, we revisited the proposal that Osh proteins are sterol transfer proteins and present new models consistent with known Osh protein functions. These models focus on the role of Osh proteins as sterol-dependent regulators of phosphoinositide and sphingolipid pathways. In contrast to their posited role as non-vesicular sterol transfer proteins, we propose that Osh proteins coordinate lipid signaling and membrane reorganization with the assembly of tethering complexes to promote molecular exchanges at membrane contact sites.
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Affiliation(s)
- Christopher T Beh
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
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Abstract
Eukaryotic organelles can interact with each other through stable junctions where the two membranes are kept in close apposition. The junction that connects the endoplasmic reticulum to the plasma membrane (ER-PM junction) is unique in providing a direct communication link between the ER and the PM. In a recently discovered signaling process, STIM (stromal-interacting molecule) proteins sense a drop in ER Ca(2+) levels and directly activate Orai PM Ca(2+) channels across the junction space. In an inverse process, a voltage-gated PM Ca(2+) channel can directly open ER ryanodine-receptor Ca(2+) channels in striated-muscle cells. Although ER-PM junctions were first described 50 years ago, their broad importance in Ca(2+) signaling, as well as in the regulation of cholesterol and phosphatidylinositol lipid transfer, has only recently been realized. Here, we discuss research from different fields to provide a broad perspective on the structures and unique roles of ER-PM junctions in controlling signaling and metabolic processes.
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Affiliation(s)
- Silvia Carrasco
- Department of Chemical and Systems Biology, School of Medicine, Stanford University, Stanford, California 94305, USA.
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Miller WL, Bose HS. Early steps in steroidogenesis: intracellular cholesterol trafficking. J Lipid Res 2011; 52:2111-2135. [PMID: 21976778 DOI: 10.1194/jlr.r016675] [Citation(s) in RCA: 356] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Steroid hormones are made from cholesterol, primarily derived from lipoproteins that enter cells via receptor-mediated endocytosis. In endo-lysosomes, cholesterol is released from cholesterol esters by lysosomal acid lipase (LAL; disordered in Wolman disease) and exported via Niemann-Pick type C (NPC) proteins (disordered in NPC disease). These diseases are characterized by accumulated cholesterol and cholesterol esters in most cell types. Mechanisms for trans-cytoplasmic cholesterol transport, membrane insertion, and retrieval from membranes are less clear. Cholesterol esters and "free" cholesterol are enzymatically interconverted in lipid droplets. Cholesterol transport to the cholesterol-poor outer mitochondrial membrane (OMM) appears to involve cholesterol transport proteins. Cytochrome P450scc (CYP11A1) then initiates steroidogenesis by converting cholesterol to pregnenolone on the inner mitochondrial membrane (IMM). Acute steroidogenic responses are regulated by cholesterol delivery from OMM to IMM, triggered by the steroidogenic acute regulatory protein (StAR). Chronic steroidogenic capacity is determined by CYP11A1 gene transcription. StAR mutations cause congenital lipoid adrenal hyperplasia, with absent steroidogenesis, potentially lethal salt loss, and 46,XY sex reversal. StAR mutations initially destroy most, but not all steroidogenesis; low levels of StAR-independent steroidogenesis are lost later due to cellular damage, explaining the clinical findings. Rare P450scc mutations cause a similar syndrome. This review addresses these early steps in steroid biosynthesis.
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Affiliation(s)
- Walter L Miller
- Department of Pediatrics, School of Medicine, University of California, San Francisco, CA 94143; UCSF Benioff Children's Hospital, San Francisco, CA 94143.
| | - Himangshu S Bose
- Department of Biochemistry, Mercer University School of Medicine, Savannah, GA 31404; and; Memorial University Medical Center, Savannah, GA 31404
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Alfaro G, Johansen J, Dighe SA, Duamel G, Kozminski KG, Beh CT. The Sterol-Binding Protein Kes1/Osh4p Is a Regulator of Polarized Exocytosis. Traffic 2011; 12:1521-36. [DOI: 10.1111/j.1600-0854.2011.01265.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Beste L, Nahar N, Dalman K, Fujioka S, Jonsson L, Dutta PC, Sitbon F. Synthesis of hydroxylated sterols in transgenic Arabidopsis plants alters growth and steroid metabolism. PLANT PHYSIOLOGY 2011; 157:426-40. [PMID: 21746809 DOI: 10.1104/pp.110.171199] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
To explore mechanisms in plant sterol homeostasis, we have here increased the turnover of sterols in Arabidopsis (Arabidopsis thaliana) and potato (Solanum tuberosum) plants by overexpressing four mouse cDNA encoding cholesterol hydroxylases (CHs), hydroxylating cholesterol at the C-7, C-24, C-25, or C-27 positions. Compared to the wild type, the four types of Arabidopsis transformant showed varying degrees of phenotypic alteration, the strongest one being in CH25 lines, which were dark-green dwarfs resembling brassinosteroid-related mutants. Gas chromatography-mass spectrometry analysis of extracts from wild-type Arabidopsis plants revealed trace levels of α and β forms of 7-hydroxycholesterol, 7-hydroxycampesterol, and 7-hydroxysitosterol. The expected hydroxycholesterol metabolites in CH7-, CH24-, and CH25 transformants were identified and quantified using gas chromatography-mass spectrometry. Additional hydroxysterol forms were also observed, particularly in CH25 plants. In CH24 and CH25 lines, but not in CH7 ones, the presence of hydroxysterols was correlated with a considerable alteration of the sterol profile and an increased sterol methyltransferase activity in microsomes. Moreover, CH25 lines contained clearly reduced levels of brassinosteroids, and displayed an enhanced drought tolerance. Equivalent transformations of potato plants with the CH25 construct increased hydroxysterol levels, but without the concomitant alteration of growth and sterol profiles observed in Arabidopsis. The results suggest that an increased hydroxylation of cholesterol and/or other sterols in Arabidopsis triggers compensatory processes, acting to maintain sterols at adequate levels.
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Affiliation(s)
- Lisa Beste
- Department of Plant Biology and Forest Genetics, Uppsala BioCenter, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
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Jamaluddin MS, Weakley SM, Zhang L, Kougias P, Lin PH, Yao Q, Chen C. miRNAs: roles and clinical applications in vascular disease. Expert Rev Mol Diagn 2011; 11:79-89. [PMID: 21171923 DOI: 10.1586/erm.10.103] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
miRNAs are small, endogenously expressed noncoding RNAs that regulate gene expression, mainly at the post-transcriptional level, via degradation or translational inhibition of their target mRNAs. Functionally, an individual miRNA can regulate the expression of multiple target genes. The study of miRNAs is rapidly growing and recent studies have revealed a significant role of miRNAs in vascular biology and disease. Many miRNAs are highly expressed in the vasculature, and their expression is dysregulated in diseased vessels. Several miRNAs have been found to be critical modulators of vascular pathologies, such as atherosclerosis, lipoprotein metabolism, inflammation, arterial remodeling, angiogenesis, smooth muscle cell regeneration, hypertension, apoptosis, neointimal hyperplasia and signal transduction pathways. Thus, miRNAs may serve as novel biomarkers and/or therapeutic targets for vascular disease. This article summarizes the current studies related to the disease correlations and functional roles of miRNAs in the vascular system and discusses the potential applications of miRNAs in vascular disease.
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Affiliation(s)
- Md Saha Jamaluddin
- Michael E DeBakey Department of Surgery, Baylor College of Medicine, One Baylor Plaza, Mail Stop: BCM391, Houston, TX 77030, USA
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Vihervaara T, Uronen RL, Wohlfahrt G, Björkhem I, Ikonen E, Olkkonen VM. Sterol binding by OSBP-related protein 1L regulates late endosome motility and function. Cell Mol Life Sci 2011; 68:537-51. [PMID: 20690035 PMCID: PMC11114714 DOI: 10.1007/s00018-010-0470-z] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 06/24/2010] [Accepted: 07/14/2010] [Indexed: 11/26/2022]
Abstract
ORP1L is an oxysterol binding homologue that regulates late endosome (LE) positioning. We show that ORP1L binds several oxysterols and cholesterol, and characterize a mutant, ORP1L Δ560-563, defective in oxysterol binding. While wild-type ORP1L clusters LE, ORP1L Δ560-563 induces LE scattering, which is reversed by disruption of the endoplasmic reticulum (ER) targeting FFAT motif, suggesting that it is due to enhanced LE-ER interactions. Endosome motility is reduced upon overexpression of ORP1L. Both wild-type ORP1L and the Δ560-563 mutant induce the recruitment of both dynactin and kinesin-2 on LE. Most of the LE decorated by overexpressed ORP1L fail to accept endocytosed dextran or EGF, and the transfected cells display defective degradation of internalized EGF. ORP1L silencing in macrophage foam cells enhances endosome motility and results in inhibition of [(3)H]cholesterol efflux to apolipoprotein A-I. These data demonstrate that LE motility and functions in both protein and lipid transport are regulated by ORP1L.
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Affiliation(s)
- Terhi Vihervaara
- Minerva Foundation Institute for Medical Research, Biomedicum Helsinki 2U, Tukholmankatu 8, 00290 Helsinki, Finland
- National Institute for Health and Welfare/Public Health Genomics Unit, Biomedicum 1, 00290 Helsinki, Finland
| | - Riikka-Liisa Uronen
- Institute of Biomedicine/Anatomy, University of Helsinki, P.O. Box 63, 00014 Helsinki, Finland
| | - Gerd Wohlfahrt
- Computer-Aided Drug Design, Orion Pharma, Orionintie 1, 02101 Espoo, Finland
| | - Ingemar Björkhem
- Karolinska Institutet, Karolinska University Hospital Huddinge, 14186 Stockholm, Sweden
| | - Elina Ikonen
- Institute of Biomedicine/Anatomy, University of Helsinki, P.O. Box 63, 00014 Helsinki, Finland
| | - Vesa M. Olkkonen
- Minerva Foundation Institute for Medical Research, Biomedicum Helsinki 2U, Tukholmankatu 8, 00290 Helsinki, Finland
- National Institute for Health and Welfare/Public Health Genomics Unit, Biomedicum 1, 00290 Helsinki, Finland
- Institute of Biomedicine/Anatomy, University of Helsinki, P.O. Box 63, 00014 Helsinki, Finland
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Jansen M, Ohsaki Y, Rega LR, Bittman R, Olkkonen VM, Ikonen E. Role of ORPs in sterol transport from plasma membrane to ER and lipid droplets in mammalian cells. Traffic 2010; 12:218-31. [PMID: 21062391 DOI: 10.1111/j.1600-0854.2010.01142.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this study, we investigated the mechanisms of sterol transport from the plasma membrane (PM) to the endoplasmic reticulum (ER) and lipid droplets (LDs) in HeLa cells. By overexpressing all mammalian oxysterol-binding protein-related proteins (ORPs), we found that especially ORP1S and ORP2 enhanced PM-to-LD sterol transport. This reflected the stimulation of transport from the PM to the ER, rather than from the ER to LDs. Double knockdown of ORP1S and ORP2 inhibited sterol transport from the PM to the ER and LDs, suggesting a physiological role for these ORPs in the process. A two phenylalanines in an acidic tract (FFAT) motif in ORPs that mediates interaction with VAMP-associated proteins (VAPs) in the ER was not necessary for the enhancement of sterol transport by ORPs. However, VAP-A and VAP-B silencing slowed down PM-to-LD sterol transport. This was accompanied by enhanced degradation of ORP2 and decreased levels of several FFAT motif-containing ORPs, suggesting a role for VAPs in sterol transport by stabilization of ORPs.
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Affiliation(s)
- Maurice Jansen
- Institute of Biomedicine, University of Helsinki, Finland
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Zhou Y, Li S, Mäyränpää MI, Zhong W, Bäck N, Yan D, Olkkonen VM. OSBP-related protein 11 (ORP11) dimerizes with ORP9 and localizes at the Golgi–late endosome interface. Exp Cell Res 2010; 316:3304-16. [DOI: 10.1016/j.yexcr.2010.06.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 06/01/2010] [Accepted: 06/07/2010] [Indexed: 11/30/2022]
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Banerji S, Ngo M, Lane CF, Robinson CA, Minogue S, Ridgway ND. Oxysterol binding protein-dependent activation of sphingomyelin synthesis in the golgi apparatus requires phosphatidylinositol 4-kinase IIα. Mol Biol Cell 2010; 21:4141-50. [PMID: 20881054 PMCID: PMC2993743 DOI: 10.1091/mbc.e10-05-0424] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The study identifies a sterol- and oxysterol binding protein (OSBP)-regulated phosphatidylinositol 4-kinase that regulates ceramide transport protein (CERT) activity and sphingomyelin (SM) synthesis. RNA interference silencing experiments identify PI4KIIα; as the mediator of Golgi recruitment of CERT, providing a potential mechanism for coordinating assembly of SM and cholesterol in the Golgi or more distal compartments. Cholesterol and sphingomyelin (SM) associate in raft domains and are metabolically coregulated. One aspect of coordinate regulation occurs in the Golgi apparatus where oxysterol binding protein (OSBP) mediates sterol-dependent activation of ceramide transport protein (CERT) activity and SM synthesis. Because CERT transfer activity is dependent on its phosphatidylinositol 4 phosphate [PtdIns(4)P]-specific pleckstrin homology domain, we investigated whether OSBP activation of CERT involved a Golgi-associated PtdIns 4-kinase (PI4K). Cell fractionation experiments revealed that Golgi/endosome-enriched membranes from 25-hydroxycholesterol-treated Chinese hamster ovary cells had increased activity of a sterol-sensitive PI4K that was blocked by small interfering RNA silencing of OSBP. Consistent with this sterol-requirement, OSBP silencing also reduced the cholesterol content of endosome/trans-Golgi network (TGN) fractions containing PI4KIIα. PI4KIIα, but not PI4KIIIβ, was required for oxysterol-activation of SM synthesis and recruitment of CERT to the Golgi apparatus. However, neither PI4KIIα nor PI4KIIIβ expression was required for 25-hydroxycholesterol–dependent translocation of OSBP to the Golgi apparatus. The presence of OSBP, CERT, and PI4KIIα in the TGN of oxysterol-stimulated cells suggests that OSBP couples sterol binding or transfer activity with regulation of PI4KIIα activity, leading to CERT recruitment to the TGN and increased SM synthesis.
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Affiliation(s)
- Sangeeta Banerji
- Departments of Pediatrics and Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, NS, Canada
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