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Ramos-Brossier M, Romeo-Guitart D, Lanté F, Boitez V, Mailliet F, Saha S, Rivagorda M, Siopi E, Nemazanyy I, Leroy C, Moriceau S, Beck-Cormier S, Codogno P, Buisson A, Beck L, Friedlander G, Oury F. Slc20a1 and Slc20a2 regulate neuronal plasticity and cognition independently of their phosphate transport ability. Cell Death Dis 2024; 15:20. [PMID: 38195526 PMCID: PMC10776841 DOI: 10.1038/s41419-023-06292-z] [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: 04/03/2023] [Revised: 11/01/2023] [Accepted: 11/13/2023] [Indexed: 01/11/2024]
Abstract
In recent years, primary familial brain calcification (PFBC), a rare neurological disease characterized by a wide spectrum of cognitive disorders, has been associated to mutations in the sodium (Na)-Phosphate (Pi) co-transporter SLC20A2. However, the functional roles of the Na-Pi co-transporters in the brain remain still largely elusive. Here we show that Slc20a1 (PiT-1) and Slc20a2 (PiT-2) are the most abundant Na-Pi co-transporters expressed in the brain and are involved in the control of hippocampal-dependent learning and memory. We reveal that Slc20a1 and Slc20a2 are differentially distributed in the hippocampus and associated with independent gene clusters, suggesting that they influence cognition by different mechanisms. Accordingly, using a combination of molecular, electrophysiological and behavioral analyses, we show that while PiT-2 favors hippocampal neuronal branching and survival, PiT-1 promotes synaptic plasticity. The latter relies on a likely Otoferlin-dependent regulation of synaptic vesicle trafficking, which impacts the GABAergic system. These results provide the first demonstration that Na-Pi co-transporters play key albeit distinct roles in the hippocampus pertaining to the control of neuronal plasticity and cognition. These findings could provide the foundation for the development of novel effective therapies for PFBC and cognitive disorders.
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Affiliation(s)
- Mariana Ramos-Brossier
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Team 8, F-75015, Paris, France.
| | - David Romeo-Guitart
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Team 8, F-75015, Paris, France
| | - Fabien Lanté
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, 38000, Grenoble, France
| | - Valérie Boitez
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Team 8, F-75015, Paris, France
| | - François Mailliet
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Team 8, F-75015, Paris, France
| | - Soham Saha
- Institut Pasteur, Perception & Memory Unit, F-75015, Paris, France
- MedInsights, 6 rue de l'église, F-02810, Veuilly la Poterie, France
| | - Manon Rivagorda
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Team 8, F-75015, Paris, France
| | - Eleni Siopi
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Team 8, F-75015, Paris, France
| | - Ivan Nemazanyy
- Platform for Metabolic Analyses, Structure Fédérative de Recherche Necker, INSERM US24/CNRS UAR, 3633, Paris, France
| | - Christine Leroy
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Team 6, F-75015, Paris, France
| | - Stéphanie Moriceau
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Team 8, F-75015, Paris, France
- Platform for Neurobehavioural and metabolism, Structure Fédérative de Recherche Necker, INSERM, US24/CNRS UAR, 3633, Paris, France
- Institute of Genetic Diseases, Imagine, 75015, Paris, France
| | - Sarah Beck-Cormier
- Nantes Université, CNRS, Inserm, l'Institut du Thorax, F-44000, Nantes, France
| | - Patrice Codogno
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Team 6, F-75015, Paris, France
| | - Alain Buisson
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, 38000, Grenoble, France
| | - Laurent Beck
- Nantes Université, CNRS, Inserm, l'Institut du Thorax, F-44000, Nantes, France.
| | - Gérard Friedlander
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Team 6, F-75015, Paris, France.
| | - Franck Oury
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Team 8, F-75015, Paris, France.
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2
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Kang M, Song A, Kim J, Kang SH, Lee SJ, Kim YS. Split genome-based retroviral replicating vectors achieve efficient gene delivery and therapeutic effect in a human glioblastoma xenograft model. BMB Rep 2022; 55:615-620. [PMID: 36195571 PMCID: PMC9813426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Indexed: 12/29/2022] Open
Abstract
The murine leukemia virus-based semi-retroviral replicating vectors (MuLV-based sRRV) had been developed to improve safety and transgene capacity for cancer gene therapy. However, despite the apparent advantages of the sRRV, improvements in the in vivo transduction efficiency are still required to deliver therapeutic genes efficiently for clinical use. In this study, we established a gibbon ape leukemia virus (GaLV) envelopepseudotyped semi-replication-competent retrovirus vector system (spRRV) which is composed of two transcomplementing replication-defective retroviral vectors termed MuLV-Gag-Pol and GaLV-Env. We found that the spRRV shows considerable improvement in efficiencies of gene transfer and spreading in both human glioblastoma cells and pre-established human glioblastoma mouse model compared with an sRRV system. When treated with ganciclovir after intratumoral injection of each vector system into pre-established U-87 MG glioblastomas, the group of mice injected with spRRV expressing the herpes simplex virus type 1-thymidine kinase (HSV1-tk) gene showed a survival rate of 100% for more than 150 days, but all control groups of mice (HSV1-tk/PBS-treated and GFP/GCV-treated groups) died within 45 days after tumor injection. In conclusion, these findings sug-gest that intratumoral delivery of the HSV1-tk gene by the spRRV system is worthy of development in clinical trials for the treatment of malignant solid tumors. [BMB Reports 2022; 55(12): 615-620].
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Affiliation(s)
- Moonkyung Kang
- Graduate School of New Drug Discovery and Development, Chungnam National University, Daejeon 34134, Korea
| | - Ayoung Song
- Institue of Molecular Biology, Inje University, Seoul 04551, Korea
| | - Jiyoung Kim
- Graduate School of New Drug Discovery and Development, Chungnam National University, Daejeon 34134, Korea
| | - Se Hun Kang
- Research Institute and Hospital, National Cancer Center of Korea, Goyang 10408, Korea
| | - Sang-Jin Lee
- Research Institute and Hospital, National Cancer Center of Korea, Goyang 10408, Korea
| | - Yeon-Soo Kim
- Graduate School of New Drug Discovery and Development, Chungnam National University, Daejeon 34134, Korea,Corresponding author. Tel: +82-42-821-8631; Fax: +82-42-821-8923; E-mail:
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Takase N, Inden M, Murayama Y, Mishima A, Kurita H, Hozumi I. PDGF-BB is involved in phosphate regulation via the phosphate transporters in human neuroblastoma SH-SY5Y cells. Biochem Biophys Res Commun 2022; 593:93-100. [PMID: 35063775 DOI: 10.1016/j.bbrc.2022.01.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 01/12/2022] [Indexed: 11/02/2022]
Abstract
Inorganic phosphate (Pi) is the second most abundant inorganic ion in the body. Since abnormalities in Pi metabolism are risk factors for various diseases, serum Pi levels are strictly controlled. Type-III sodium-dependent Pi transporters, PiT-1 (encoded by SLC20A1) and PiT-2 (encoded by SLC20A2), are distributed throughout the tissues of the body, including the central nervous system, and are known to be responsible for extracellular to intracellular Pi transport. Platelet-derived growth factor (PDGF) is a major growth factor of mesenchymal cells. PDGF-BB, a homodimer of PDGF-B, regulates intracellular Pi by increasing PiT-1 expression in vascular smooth muscle cells. However, the effects of PDGF-BB on Pi transporters in neurons have yet to be reported. Here, we investigated the effect of PDGF-BB on Pi transporters in human neuroblastoma SH-SY5Y cells. PDGF-BB did not induce SLC20A1 mRNA expression, but it increased the intracellular uptake of Pi via PiT-1 in SH-SY5Y cells. Among the signaling pathways associated with PDGF-BB, AKT signaling was shown to be involved in the increase in Pi transport. In addition, the PDGF-BB-induced increase in Pi mediated neuroprotective effects in SLC20A2-suppressed cells, in an in vitro model of the pathological condition found in idiopathic basal ganglia calcification. Moreover, the increase in Pi uptake was found to occur through promotion of intracellular PiT-1 translocation to the plasma membrane. Overall, these results indicate that PDGF-BB exerts neuroprotective effects via Pi transport, and they demonstrate the potential utility of PDGF-BB against abnormal Pi metabolism in neurons.
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Affiliation(s)
- Naoko Takase
- Laboratory of Medical Therapeutics and Molecular Therapeutics, Department Biomedical Pharmaceutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi Gifu city, Gifu, 501-1196, Japan
| | - Masatoshi Inden
- Laboratory of Medical Therapeutics and Molecular Therapeutics, Department Biomedical Pharmaceutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi Gifu city, Gifu, 501-1196, Japan.
| | - Yuto Murayama
- Laboratory of Medical Therapeutics and Molecular Therapeutics, Department Biomedical Pharmaceutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi Gifu city, Gifu, 501-1196, Japan
| | - Ayane Mishima
- Laboratory of Medical Therapeutics and Molecular Therapeutics, Department Biomedical Pharmaceutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi Gifu city, Gifu, 501-1196, Japan
| | - Hisaka Kurita
- Laboratory of Medical Therapeutics and Molecular Therapeutics, Department Biomedical Pharmaceutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi Gifu city, Gifu, 501-1196, Japan
| | - Isao Hozumi
- Laboratory of Medical Therapeutics and Molecular Therapeutics, Department Biomedical Pharmaceutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi Gifu city, Gifu, 501-1196, Japan.
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4
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Figueres L, Beck-Cormier S, Beck L, Marks J. The Complexities of Organ Crosstalk in Phosphate Homeostasis: Time to Put Phosphate Sensing Back in the Limelight. Int J Mol Sci 2021; 22:5701. [PMID: 34071837 PMCID: PMC8199323 DOI: 10.3390/ijms22115701] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 05/13/2021] [Accepted: 05/21/2021] [Indexed: 12/16/2022] Open
Abstract
Phosphate homeostasis is essential for health and is achieved via interaction between the bone, kidney, small intestine, and parathyroid glands and via intricate processes involving phosphate transporters, phosphate sensors, and circulating hormones. Numerous genetic and acquired disorders are associated with disruption in these processes and can lead to significant morbidity and mortality. The role of the kidney in phosphate homeostasis is well known, although it is recognized that the cellular mechanisms in murine models and humans are different. Intestinal phosphate transport also appears to differ in humans and rodents, with recent studies demonstrating a dominant role for the paracellular pathway. The existence of phosphate sensing has been acknowledged for decades; however, the underlying molecular mechanisms are poorly understood. At least three phosphate sensors have emerged. PiT2 and FGFR1c both act as phosphate sensors controlling Fibroblast Growth Factor 23 secretion in bone, whereas the calcium-sensing receptor controls parathyroid hormone secretion in response to extracellular phosphate. All three of the proposed sensors are expressed in the kidney and intestine but their exact function in these organs is unknown. Understanding organ interactions and the mechanisms involved in phosphate sensing requires significant research to develop novel approaches for the treatment of phosphate homeostasis disorders.
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Affiliation(s)
- Lucile Figueres
- Department of Neuroscience, Physiology and Pharmacology, Royal Free Campus, University College London, London NW3 2PF, UK;
- CHU de Nantes, Université de Nantes, F-44042 Nantes, France
| | - Sarah Beck-Cormier
- Inserm, UMR 1229, RMeS Regenerative Medicine and Skeleton, Université de Nantes, ONIRIS, F-44042 Nantes, France; (S.B.-C.); (L.B.)
| | - Laurent Beck
- Inserm, UMR 1229, RMeS Regenerative Medicine and Skeleton, Université de Nantes, ONIRIS, F-44042 Nantes, France; (S.B.-C.); (L.B.)
| | - Joanne Marks
- Department of Neuroscience, Physiology and Pharmacology, Royal Free Campus, University College London, London NW3 2PF, UK;
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Couasnay G, Bon N, Devignes CS, Sourice S, Bianchi A, Véziers J, Weiss P, Elefteriou F, Provot S, Guicheux J, Beck-Cormier S, Beck L. PiT1/Slc20a1 Is Required for Endoplasmic Reticulum Homeostasis, Chondrocyte Survival, and Skeletal Development. J Bone Miner Res 2019; 34:387-398. [PMID: 30347511 DOI: 10.1002/jbmr.3609] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 09/26/2018] [Accepted: 10/22/2018] [Indexed: 01/09/2023]
Abstract
During skeletal mineralization, the sodium-phosphate co-transporter PiT1Slc20a1 is assumed to meet the phosphate requirements of bone-forming cells, although evidence is missing. Here, we used a conditional gene deletion approach to determine the role of PiT1 in growth plate chondrocytes. We show that PiT1 ablation shortly after birth generates a rapid and massive cell death in the center of the growth plate, together with an uncompensated endoplasmic reticulum (ER) stress, characterized by morphological changes and increased Chop, Atf4, and Bip expression. PiT1 expression in chondrocytes was not found at the cell membrane but co-localized with the ER marker ERp46, and was upregulated by the unfolded protein response cascade. In addition, we identified the protein disulfide isomerase (Pdi) ER chaperone as a PiT1 binding partner and showed that PiT1 ablation impaired Pdi reductase activity. The ER stress induced by PiT1 deficiency in chondrocytes was associated with intracellular retention of aggrecan and vascular endothelial growth factor A (Vegf-A), which was rescued by overexpressing a phosphate transport-deficient mutant of PiT1. Our data thus reveal a novel, Pi-transport independent function of PiT1, as a critical modulator of ER homeostasis and chondrocyte survival during endochondral ossification. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Greig Couasnay
- INSERM, Unité mixte de Recherche (UMR) 1229, Regenerative Medicine and Skeleton (RMeS), Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, ONIRIS, Université de Nantes, Nantes, France.,Faculty of Dental Surgery of Nantes (UFR Odontologie), Université de Nantes, Nantes, France.,Department of Molecular and Human Genetics and Orthopedic Surgery, Baylor College of Medicine, Houston, TX, USA
| | - Nina Bon
- INSERM, Unité mixte de Recherche (UMR) 1229, Regenerative Medicine and Skeleton (RMeS), Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, ONIRIS, Université de Nantes, Nantes, France.,Faculty of Dental Surgery of Nantes (UFR Odontologie), Université de Nantes, Nantes, France
| | - Claire-Sophie Devignes
- INSERM, UMR 1132, Centre Viggo Petersen-Hôpital Lariboisière, Paris, France.,Université Paris Diderot, Sorbonne Paris-Cité, Paris, France
| | - Sophie Sourice
- INSERM, Unité mixte de Recherche (UMR) 1229, Regenerative Medicine and Skeleton (RMeS), Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, ONIRIS, Université de Nantes, Nantes, France.,Faculty of Dental Surgery of Nantes (UFR Odontologie), Université de Nantes, Nantes, France
| | - Arnaud Bianchi
- National Center for Scientific Research (CNRS), UMR 7365, IMoPA, Vandœuvre-lès-Nancy, France.,Faculté de Médecine, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Joëlle Véziers
- INSERM, Unité mixte de Recherche (UMR) 1229, Regenerative Medicine and Skeleton (RMeS), Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, ONIRIS, Université de Nantes, Nantes, France.,Faculty of Dental Surgery of Nantes (UFR Odontologie), Université de Nantes, Nantes, France.,PHU 4 Odontologie, Neurochirurgie, Neurotraumatologie (OTONN), CHU de Nantes University Hospital Center, Nantes, France
| | - Pierre Weiss
- INSERM, Unité mixte de Recherche (UMR) 1229, Regenerative Medicine and Skeleton (RMeS), Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, ONIRIS, Université de Nantes, Nantes, France.,Faculty of Dental Surgery of Nantes (UFR Odontologie), Université de Nantes, Nantes, France.,PHU 4 Odontologie, Neurochirurgie, Neurotraumatologie (OTONN), CHU de Nantes University Hospital Center, Nantes, France
| | - Florent Elefteriou
- Department of Molecular and Human Genetics and Orthopedic Surgery, Baylor College of Medicine, Houston, TX, USA
| | - Sylvain Provot
- INSERM, UMR 1132, Centre Viggo Petersen-Hôpital Lariboisière, Paris, France.,Université Paris Diderot, Sorbonne Paris-Cité, Paris, France
| | - Jérôme Guicheux
- INSERM, Unité mixte de Recherche (UMR) 1229, Regenerative Medicine and Skeleton (RMeS), Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, ONIRIS, Université de Nantes, Nantes, France.,Faculty of Dental Surgery of Nantes (UFR Odontologie), Université de Nantes, Nantes, France.,PHU 4 Odontologie, Neurochirurgie, Neurotraumatologie (OTONN), CHU de Nantes University Hospital Center, Nantes, France
| | - Sarah Beck-Cormier
- INSERM, Unité mixte de Recherche (UMR) 1229, Regenerative Medicine and Skeleton (RMeS), Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, ONIRIS, Université de Nantes, Nantes, France.,Faculty of Dental Surgery of Nantes (UFR Odontologie), Université de Nantes, Nantes, France
| | - Laurent Beck
- INSERM, Unité mixte de Recherche (UMR) 1229, Regenerative Medicine and Skeleton (RMeS), Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, ONIRIS, Université de Nantes, Nantes, France.,Faculty of Dental Surgery of Nantes (UFR Odontologie), Université de Nantes, Nantes, France
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6
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Jacquillet G, Unwin RJ. Physiological regulation of phosphate by vitamin D, parathyroid hormone (PTH) and phosphate (Pi). Pflugers Arch 2019; 471:83-98. [PMID: 30393837 PMCID: PMC6326012 DOI: 10.1007/s00424-018-2231-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 10/20/2018] [Accepted: 10/25/2018] [Indexed: 01/05/2023]
Abstract
Inorganic phosphate (Pi) is an abundant element in the body and is essential for a wide variety of key biological processes. It plays an essential role in cellular energy metabolism and cell signalling, e.g. adenosine and guanosine triphosphates (ATP, GTP), and in the composition of phospholipid membranes and bone, and is an integral part of DNA and RNA. It is an important buffer in blood and urine and contributes to normal acid-base balance. Given its widespread role in almost every molecular and cellular function, changes in serum Pi levels and balance can have important and untoward effects. Pi homoeostasis is maintained by a counterbalance between dietary Pi absorption by the gut, mobilisation from bone and renal excretion. Approximately 85% of total body Pi is present in bone and only 1% is present as free Pi in extracellular fluids. In humans, extracellular concentrations of inorganic Pi vary between 0.8 and 1.2 mM, and in plasma or serum Pi exists in both its monovalent and divalent forms (H2PO4- and HPO42-). In the intestine, approximately 30% of Pi absorption is vitamin D regulated and dependent. To help maintain Pi balance, reabsorption of filtered Pi along the renal proximal tubule (PT) is via the NaPi-IIa and NaPi-IIc Na+-coupled Pi cotransporters, with a smaller contribution from the PiT-2 transporters. Endocrine factors, including, vitamin D and parathyroid hormone (PTH), as well as newer factors such as fibroblast growth factor (FGF)-23 and its coreceptor α-klotho, are intimately involved in the control of Pi homeostasis. A tight regulation of Pi is critical, since hyperphosphataemia is associated with increased cardiovascular morbidity in chronic kidney disease (CKD) and hypophosphataemia with rickets and growth retardation. This short review considers the control of Pi balance by vitamin D, PTH and Pi itself, with an emphasis on the insights gained from human genetic disorders and genetically modified mouse models.
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Affiliation(s)
- Grégory Jacquillet
- Centre for Nephrology, University College London (UCL), Royal Free Campus, Rowland Hill Street, London, NW3 2PF, UK
| | - Robert J Unwin
- Centre for Nephrology, University College London (UCL), Royal Free Campus, Rowland Hill Street, London, NW3 2PF, UK.
- AstraZeneca IMED ECD CVRM R&D, Gothenburg, Sweden.
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7
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Robinson-McCarthy LR, McCarthy KR, Raaben M, Piccinotti S, Nieuwenhuis J, Stubbs SH, Bakkers MJG, Whelan SPJ. Reconstruction of the cell entry pathway of an extinct virus. PLoS Pathog 2018; 14:e1007123. [PMID: 30080900 PMCID: PMC6095630 DOI: 10.1371/journal.ppat.1007123] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/16/2018] [Accepted: 07/16/2018] [Indexed: 12/16/2022] Open
Abstract
Endogenous retroviruses (ERVs), remnants of ancient germline infections, comprise 8% of the human genome. The most recently integrated includes human ERV-K (HERV-K) where several envelope (env) sequences remain intact. Viral pseudotypes decorated with one of those Envs are infectious. Using a recombinant vesicular stomatitis virus encoding HERV-K Env as its sole attachment and fusion protein (VSV-HERVK) we conducted a genome-wide haploid genetic screen to interrogate the host requirements for infection. This screen identified 11 genes involved in heparan sulfate biosynthesis. Genetic inhibition or chemical removal of heparan sulfate and addition of excess soluble heparan sulfate inhibit infection. Direct binding of heparin to soluble HERV-K Env and purified VSV-HERVK defines it as critical for viral attachment. Cell surface bound VSV-HERVK particles are triggered to infect on exposure to acidic pH, whereas acid pH pretreatment of virions blocks infection. Testing of additional endogenous HERV-K env sequences reveals they bind heparin and mediate acid pH triggered fusion. This work reconstructs and defines key steps in the infectious entry pathway of an extinct virus.
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Affiliation(s)
- Lindsey R. Robinson-McCarthy
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Kevin R. McCarthy
- Laboratory of Molecular Medicine, Children’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Matthijs Raaben
- Division of Biochemistry, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Silvia Piccinotti
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Joppe Nieuwenhuis
- Division of Biochemistry, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Sarah H. Stubbs
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mark J. G. Bakkers
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sean P. J. Whelan
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
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8
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Greenwood AD, Ishida Y, O'Brien SP, Roca AL, Eiden MV. Transmission, Evolution, and Endogenization: Lessons Learned from Recent Retroviral Invasions. Microbiol Mol Biol Rev 2018; 82:e00044-17. [PMID: 29237726 PMCID: PMC5813887 DOI: 10.1128/mmbr.00044-17] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Viruses of the subfamily Orthoretrovirinae are defined by the ability to reverse transcribe an RNA genome into DNA that integrates into the host cell genome during the intracellular virus life cycle. Exogenous retroviruses (XRVs) are horizontally transmitted between host individuals, with disease outcome depending on interactions between the retrovirus and the host organism. When retroviruses infect germ line cells of the host, they may become endogenous retroviruses (ERVs), which are permanent elements in the host germ line that are subject to vertical transmission. These ERVs sometimes remain infectious and can themselves give rise to XRVs. This review integrates recent developments in the phylogenetic classification of retroviruses and the identification of retroviral receptors to elucidate the origins and evolution of XRVs and ERVs. We consider whether ERVs may recurrently pressure XRVs to shift receptor usage to sidestep ERV interference. We discuss how related retroviruses undergo alternative fates in different host lineages after endogenization, with koala retrovirus (KoRV) receiving notable interest as a recent invader of its host germ line. KoRV is heritable but also infectious, which provides insights into the early stages of germ line invasions as well as XRV generation from ERVs. The relationship of KoRV to primate and other retroviruses is placed in the context of host biogeography and the potential role of bats and rodents as vectors for interspecies viral transmission. Combining studies of extant XRVs and "fossil" endogenous retroviruses in koalas and other Australasian species has broadened our understanding of the evolution of retroviruses and host-retrovirus interactions.
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Affiliation(s)
- Alex D Greenwood
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research (IZW) in the Forschungsverbund Berlin e.V., Berlin, Germany
| | - Yasuko Ishida
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Sean P O'Brien
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Alfred L Roca
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Maribeth V Eiden
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research (IZW) in the Forschungsverbund Berlin e.V., Berlin, Germany
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9
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Bon N, Couasnay G, Bourgine A, Sourice S, Beck-Cormier S, Guicheux J, Beck L. Phosphate (P i)-regulated heterodimerization of the high-affinity sodium-dependent P i transporters PiT1/Slc20a1 and PiT2/Slc20a2 underlies extracellular P i sensing independently of P i uptake. J Biol Chem 2017; 293:2102-2114. [PMID: 29233890 DOI: 10.1074/jbc.m117.807339] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 11/16/2017] [Indexed: 12/24/2022] Open
Abstract
Extracellular phosphate (Pi) can act as a signaling molecule that directly alters gene expression and cellular physiology. The ability of cells or organisms to detect changes in extracellular Pi levels implies the existence of a Pi-sensing mechanism that signals to the body or individual cell. However, unlike in prokaryotes, yeasts, and plants, the molecular players involved in Pi sensing in mammals remain unknown. In this study, we investigated the involvement of the high-affinity, sodium-dependent Pi transporters PiT1 and PiT2 in mediating Pi signaling in skeletal cells. We found that deletion of PiT1 or PiT2 blunted the Pi-dependent ERK1/2-mediated phosphorylation and subsequent gene up-regulation of the mineralization inhibitors matrix Gla protein and osteopontin. This result suggested that both PiTs are necessary for Pi signaling. Moreover, the ERK1/2 phosphorylation could be rescued by overexpressing Pi transport-deficient PiT mutants. Using cross-linking and bioluminescence resonance energy transfer approaches, we found that PiT1 and PiT2 form high-abundance homodimers and Pi-regulated low-abundance heterodimers. Interestingly, in the absence of sodium-dependent Pi transport activity, the PiT1-PiT2 heterodimerization was still regulated by extracellular Pi levels. Of note, when two putative Pi-binding residues, Ser-128 (in PiT1) and Ser-113 (in PiT2), were substituted with alanine, the PiT1-PiT2 heterodimerization was no longer regulated by extracellular Pi These observations suggested that Pi binding rather than Pi uptake may be the key factor in mediating Pi signaling through the PiT proteins. Taken together, these results demonstrate that Pi-regulated PiT1-PiT2 heterodimerization mediates Pi sensing independently of Pi uptake.
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Affiliation(s)
- Nina Bon
- From INSERM, U1229, RMeS "Regenerative Medicine and Skeleton," STEP team "Skeletal Physiopathology and Joint Regenerative Medicine," Nantes F-44042, France.,the Université de Nantes, UMR-S 1229, RMeS, UFR Odontologie, Nantes F-44042, France, and
| | - Greig Couasnay
- From INSERM, U1229, RMeS "Regenerative Medicine and Skeleton," STEP team "Skeletal Physiopathology and Joint Regenerative Medicine," Nantes F-44042, France.,the Université de Nantes, UMR-S 1229, RMeS, UFR Odontologie, Nantes F-44042, France, and
| | - Annabelle Bourgine
- From INSERM, U1229, RMeS "Regenerative Medicine and Skeleton," STEP team "Skeletal Physiopathology and Joint Regenerative Medicine," Nantes F-44042, France.,the Université de Nantes, UMR-S 1229, RMeS, UFR Odontologie, Nantes F-44042, France, and
| | - Sophie Sourice
- From INSERM, U1229, RMeS "Regenerative Medicine and Skeleton," STEP team "Skeletal Physiopathology and Joint Regenerative Medicine," Nantes F-44042, France.,the Université de Nantes, UMR-S 1229, RMeS, UFR Odontologie, Nantes F-44042, France, and
| | - Sarah Beck-Cormier
- From INSERM, U1229, RMeS "Regenerative Medicine and Skeleton," STEP team "Skeletal Physiopathology and Joint Regenerative Medicine," Nantes F-44042, France.,the Université de Nantes, UMR-S 1229, RMeS, UFR Odontologie, Nantes F-44042, France, and
| | - Jérôme Guicheux
- From INSERM, U1229, RMeS "Regenerative Medicine and Skeleton," STEP team "Skeletal Physiopathology and Joint Regenerative Medicine," Nantes F-44042, France.,the Université de Nantes, UMR-S 1229, RMeS, UFR Odontologie, Nantes F-44042, France, and.,CHU Nantes, PHU 4 OTONN, Nantes F-44042, France
| | - Laurent Beck
- From INSERM, U1229, RMeS "Regenerative Medicine and Skeleton," STEP team "Skeletal Physiopathology and Joint Regenerative Medicine," Nantes F-44042, France, .,the Université de Nantes, UMR-S 1229, RMeS, UFR Odontologie, Nantes F-44042, France, and
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10
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Larsen FT, Jensen N, Autzen JK, Kongsfelt IB, Pedersen L. Primary Brain Calcification Causal PiT2 Transport-Knockout Variants can Exert Dominant Negative Effects on Wild-Type PiT2 Transport Function in Mammalian Cells. J Mol Neurosci 2016; 61:215-220. [PMID: 27943094 PMCID: PMC5321689 DOI: 10.1007/s12031-016-0868-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Accepted: 11/22/2016] [Indexed: 12/31/2022]
Abstract
Primary brain calcification (PBC) is a neurodegenerative disorder characterized by calcium-phosphate deposits in the basal ganglia and often also other areas of the brain. The prevalent clinical manifestations are cognitive impairment, neuropsychiatric symptoms, and movement disorders. In recent years, monoallelic variants in SLC20A2, which encodes the type III sodium-dependent inorganic phosphate (Pi) transporter 2 (PiT2), have been linked to the familial form of PBC in 40–50% of the families reported worldwide as well as to sporadic cases of PBC. Further insight into the disease mechanism is, however, needed. Based on co-expression studies of wild-type and variant PiT2 in Xenopus laevis oocytes, the molecular disease mechanism associated with SLC20A2 missense variants has formerly been suggested to be haploinsufficiency. We have here used mammalian cells isolated from a Slc20a2−/− mouse and co-expression of human wild-type and variant PiT2. Two of the variants studied have both been reported twice in unrelated PBC cases: PiT2D28N in two sporadic cases and PiT2E575K in a familial and a sporadic case. We find that in mammalian cells, the analyzed SLC20A2 missense variants can exert their effect in a dominant negative manner resulting in decreased wild-type PiT2 Pi transport. Thus, compared to monoallelic lack of functional PiT2 protein expression, which reasonably points towards haploinsufficiency, certain SLC20A2 missense variants may be more detrimental for cellular Pi uptake and potentially contribute to an earlier disease onset and/or a more severe phenotype as observed for Slc20a2−/− mice compared to Slc20a2+/− mice.
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Affiliation(s)
- Frederik Tibert Larsen
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Møllers Allé 3, Building 1130, 8000, Aarhus, Denmark
| | - Nina Jensen
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Møllers Allé 3, Building 1130, 8000, Aarhus, Denmark.,Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Jacob Kwasi Autzen
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Møllers Allé 3, Building 1130, 8000, Aarhus, Denmark
| | - Iben Boutrup Kongsfelt
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Møllers Allé 3, Building 1130, 8000, Aarhus, Denmark
| | - Lene Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Møllers Allé 3, Building 1130, 8000, Aarhus, Denmark. .,Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
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11
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Functional Interplay Between Murine Leukemia Virus Glycogag, Serinc5, and Surface Glycoprotein Governs Virus Entry, with Opposite Effects on Gammaretroviral and Ebolavirus Glycoproteins. mBio 2016; 7:mBio.01985-16. [PMID: 27879338 PMCID: PMC5120145 DOI: 10.1128/mbio.01985-16] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gammaretroviruses, such as murine leukemia viruses (MLVs), encode, in addition to the canonical Gag, Pol, and Env proteins that will form progeny virus particles, a protein called “glycogag” (glycosylated Gag). MLV glycogag contains the entire Gag sequence plus an 88-residue N-terminal extension. It has recently been reported that glycogag, like the Nef protein of HIV-1, counteracts the antiviral effects of the cellular protein Serinc5. We have found, in agreement with prior work, that glycogag strongly enhances the infectivity of MLVs with some Env proteins but not those with others. In contrast, however, glycogag was detrimental to MLVs carrying Ebolavirus glycoprotein. Glycogag could be replaced, with respect to viral infectivity, by the unrelated S2 protein of equine infectious anemia virus. We devised an assay for viral entry in which virus particles deliver the Cre recombinase into cells, leading to the expression of a reporter. Data from this assay showed that both the positive and the negative effects of glycogag and S2 upon MLV infectivity are exerted at the level of virus entry. Moreover, transfection of the virus-producing cells with a Serinc5 expression plasmid reduced the infectivity and entry capability of MLV carrying xenotropic MLV Env, particularly in the absence of glycogag. Conversely, Serinc5 expression abrogated the negative effects of glycogag upon the infectivity and entry capability of MLV carrying Ebolavirus glycoprotein. As Serinc5 may influence cellular phospholipid metabolism, it seems possible that all of these effects on virus entry derive from changes in the lipid composition of viral membranes. Many murine leukemia viruses (MLVs) encode a protein called “glycogag.” The function of glycogag is not fully understood, but it can assist HIV-1 replication in the absence of the HIV-1 protein Nef under some circumstances. In turn, Nef counteracts the cellular protein Serinc5. Glycogag enhances the infectivity of MLVs with some but not all MLV Env proteins (which mediate viral entry into the host cell upon binding to cell surface receptors). We now report that glycogag acts by enhancing viral entry and that, like Nef, glycogag antagonizes Serinc5. Surprisingly, the effects of glycogag and Serinc5 upon the entry and infectivity of MLV particles carrying an Ebolavirus glycoprotein are the opposite of those observed with the MLV Env proteins. The unrelated S2 protein of equine infectious anemia virus (EIAV) is functionally analogous to glycogag in our experiments. Thus, three retroviruses (HIV-1, MLV, and EIAV) have independently evolved accessory proteins that counteract Serinc5.
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12
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Disruption of the Phosphate Transporter Pit1 in Hepatocytes Improves Glucose Metabolism and Insulin Signaling by Modulating the USP7/IRS1 Interaction. Cell Rep 2016; 16:2736-2748. [PMID: 27568561 DOI: 10.1016/j.celrep.2016.08.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 06/02/2016] [Accepted: 08/03/2016] [Indexed: 01/07/2023] Open
Abstract
The liver plays a central role in whole-body lipid and glucose homeostasis. Increasing dietary fat intake results in increased hepatic fat deposition, which is associated with a risk for development of insulin resistance and type 2 diabetes. In this study, we demonstrate a role for the phosphate inorganic transporter 1 (PiT1/SLC20A1) in regulating metabolism. Specific knockout of Pit1 in hepatocytes significantly improved glucose tolerance and insulin sensitivity, enhanced insulin signaling, and decreased hepatic lipogenesis. We identified USP7 as a PiT1 binding partner and demonstrated that Pit1 deletion inhibited USP7/IRS1 dissociation upon insulin stimulation. This prevented IRS1 ubiquitination and its subsequent proteasomal degradation. As a consequence, delayed insulin negative feedback loop and sustained insulin signaling were observed. Moreover, PiT1-deficient mice were protected against high-fat-diet-induced obesity and diabetes. Our findings indicate that PiT1 has potential as a therapeutic target in the context of metabolic syndrome, obesity, and diabetes.
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13
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Linking Gene Expression in the Intestine to Production of Gametes Through the Phosphate Transporter PITR-1 in Caenorhabditis elegans. Genetics 2016; 204:153-62. [PMID: 27449055 PMCID: PMC5012382 DOI: 10.1534/genetics.116.188532] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 07/12/2016] [Indexed: 12/31/2022] Open
Abstract
Inorganic phosphate is an essential mineral for both prokaryotic and eukaryotic cell metabolism and structure. Its uptake into the cell is mediated by membrane-bound transporters and coupled to Na+ transport. Mammalian sodium-dependent Pi cotransporters have been grouped into three families NaPi-I, NaPi-II, and NaPi-III. Despite being discovered more than two decades ago, very little is known about requirements for NaPi-III transporters in vivo, in the context of intact animal models. Here we find that impaired function of the Caenorhabditis elegans NaPi-III transporter, pitr-1, results in decreased brood size and dramatically increased expression of vitellogenin by the worm intestine. Unexpectedly, we found that the effects of pitr-1 mutation on vitellogenin expression in the intestine could only be rescued by expression of pitr-1 in the germline, and not by expression of pitr-1 in the intestine itself. Our results indicate the existence of a signal from the germline that regulates gene expression in the intestine, perhaps linking nutrient export from the intestine to production of gametes by the germline.
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14
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Affiliation(s)
- A Dusty Miller
- Fred Hutchinson Cancer Research Center , Seattle, WA 98109
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15
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Genetic diversity of koala retroviral envelopes. Viruses 2015; 7:1258-70. [PMID: 25789509 PMCID: PMC4379569 DOI: 10.3390/v7031258] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 03/04/2015] [Accepted: 03/11/2015] [Indexed: 01/03/2023] Open
Abstract
Genetic diversity, attributable to the low fidelity of reverse transcription, recombination and mutation, is an important feature of infectious retroviruses. Under selective pressure, such as that imposed by superinfection interference, gammaretroviruses commonly adapt their envelope proteins to use alternative receptors to overcome this entry block. The first characterized koala retroviruses KoRV subgroup A (KoRV-A) were remarkable in their absence of envelope genetic variability. Once it was determined that KoRV-A was present in all koalas in US zoos, regardless of their disease status, we sought to isolate a KoRV variant whose presence correlated with neoplastic malignancies. More than a decade after the identification of KoRV-A, we isolated a second subgroup of KoRV, KoRV-B from koalas with lymphomas. The envelope proteins of KoRV-A and KoRV-B are sufficiently divergent to confer the ability to bind and employ distinct receptors for infection. We have now obtained a number of additional KoRV envelope variants. In the present studies we report these variants, and show that they differ from KoRV-A and KoRV-B envelopes in their host range and superinfection interference properties. Thus, there appears to be considerable variation among KoRVs envelope genes suggesting genetic diversity is a factor following the KoRV-A infection process.
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16
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Kozak CA. Origins of the endogenous and infectious laboratory mouse gammaretroviruses. Viruses 2014; 7:1-26. [PMID: 25549291 PMCID: PMC4306825 DOI: 10.3390/v7010001] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 12/18/2014] [Indexed: 01/07/2023] Open
Abstract
The mouse gammaretroviruses associated with leukemogenesis are found in the classical inbred mouse strains and in house mouse subspecies as infectious exogenous viruses (XRVs) and as endogenous retroviruses (ERVs) inserted into their host genomes. There are three major mouse leukemia virus (MuLV) subgroups in laboratory mice: ecotropic, xenotropic, and polytropic. These MuLV subgroups differ in host range, pathogenicity, receptor usage and subspecies of origin. The MuLV ERVs are recent acquisitions in the mouse genome as demonstrated by the presence of many full-length nondefective MuLV ERVs that produce XRVs, the segregation of these MuLV subgroups into different house mouse subspecies, and by the positional polymorphism of these loci among inbred strains and individual wild mice. While some ecotropic and xenotropic ERVs can produce XRVs directly, others, especially the pathogenic polytropic ERVs, do so only after recombinations that can involve all three ERV subgroups. Here, I describe individual MuLV ERVs found in the laboratory mice, their origins and geographic distribution in wild mouse subspecies, their varying ability to produce infectious virus and the biological consequences of this expression.
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17
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Kongsfelt IB, Byskov K, Pedersen LE, Pedersen L. High levels of the type III inorganic phosphate transporter PiT1 (SLC20A1) can confer faster cell adhesion. Exp Cell Res 2014; 326:57-67. [PMID: 24880124 DOI: 10.1016/j.yexcr.2014.05.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Revised: 05/18/2014] [Accepted: 05/20/2014] [Indexed: 01/16/2023]
Abstract
The inorganic phosphate transporter PiT1 (SLC20A1) is ubiquitously expressed in mammalian cells. We recently showed that overexpression of human PiT1 was sufficient to increase proliferation of two strict density-inhibited cell lines, murine fibroblastic NIH3T3 and pre-osteoblastic MC3T3-E1 cells, and allowed the cultures to grow to higher cell densities. In addition, upon transformation NIH3T3 cells showed increased ability to form colonies in soft agar. The cellular regulation of PiT1 expression supports that cells utilize the PiT1 levels to control proliferation, with non-proliferating cells showing the lowest PiT1 mRNA levels. The mechanism behind the role of PiT1 in increased cell proliferation is not known. We, however, found that compared to control cells, cultures of NIH3T3 cells overexpressing PiT1 upon seeding showed increased cell number after 24h and had shifted more cells from G0/G1 to S+G2/M within 12h, suggesting that an early event may play a role. We here show that expression of human PiT1 in NIH3T3 cells led to faster cell adhesion; this effect was not cell type specific in that it was also observed when expressing human PiT1 in MC3T3-E1 cells. We also show for NIH3T3 that PiT1 overexpression led to faster cell spreading. The final total numbers of attached cells did, however, not differ between cultures of PiT1 overexpressing cells and control cells of neither cell type. We suggest that the PiT1-mediated fast adhesion potentials allow the cells to go faster out of G0/G1 and thereby contribute to their proliferative advantage within the first 24h after seeding.
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Affiliation(s)
| | - Kristina Byskov
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | | | - Lene Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Hematology, Aarhus University Hospital, Aarhus, Denmark.
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18
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Mazari PM, Roth MJ. Library screening and receptor-directed targeting of gammaretroviral vectors. Future Microbiol 2013; 8:107-21. [PMID: 23252496 DOI: 10.2217/fmb.12.122] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Gene- and cell-based therapies hold great potential for the advancement of the personalized medicine movement. Gene therapy vectors have made dramatic leaps forward since their inception. Retroviral-based vectors were the first to gain clinical attention and still offer the best hope for the long-term correction of many disorders. The fear of nonspecific transduction makes targeting a necessary feature for most clinical applications. However, this remains a difficult feature to optimize, with specificity often coming at the expense of efficiency. The aim of this article is to discuss the various methods employed to retarget retroviral entry. Our focus will lie on the modification of gammaretroviral envelope proteins with an in-depth discussion of the creation and screening of envelope libraries.
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Affiliation(s)
- Peter M Mazari
- University of Medicine & Dentistry of NJ-Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA
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19
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Mice lacking the sodium-dependent phosphate import protein, PiT1 (SLC20A1), have a severe defect in terminal erythroid differentiation and early B cell development. Exp Hematol 2013; 41:432-43.e7. [PMID: 23376999 DOI: 10.1016/j.exphem.2013.01.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 01/07/2013] [Accepted: 01/16/2013] [Indexed: 11/21/2022]
Abstract
Phosphate is critical in multiple biological processes (phosphorylation reactions, ATP production, and DNA structure and synthesis). It remains unclear how individual cells initially sense changes in phosphate availability and the cellular consequences of these changes. PiT1 (or SLC20A1) is a constitutively expressed, high-affinity sodium-dependent phosphate import protein. In vitro data suggest that PiT1 serves a direct role in mediating cellular proliferation; its role in vivo is unclear. We have discovered that mice lacking PiT1 develop a profound underproduction anemia characterized by mild macrocytosis, dyserythropoiesis, increased apoptosis, and a near complete block in terminal erythroid differentiation. In addition, the animals are severely B cell lymphopenic because of a defect in pro-B cell development and mildly neutropenic. The phenotype is intrinsic to the hematopoietic system, is associated with a defect in cell cycle progression, and occurs in the absence of changes in serum phosphate or calcium concentrations and independently of a change in cellular phosphate uptake. The severity of the anemia and block in terminal erythroid differentiation and B cell lymphopenia are striking and suggest that PiT1 serves a fundamental and nonredundant role in murine terminal erythroid differentiation and B cell development. Intriguingly, as the anemia mimics the ineffective erythropoiesis in some low-grade human myelodysplastic syndromes, this murine model might also provide pathologic insight into these disorders.
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Dufait I, Liechtenstein T, Lanna A, Bricogne C, Laranga R, Padella A, Breckpot K, Escors D. Retroviral and lentiviral vectors for the induction of immunological tolerance. SCIENTIFICA 2012; 2012:694137. [PMID: 23526794 PMCID: PMC3605697 DOI: 10.6064/2012/694137] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Retroviral and lentiviral vectors have proven to be particularly efficient systems to deliver genes of interest into target cells, either in vivo or in cell cultures. They have been used for some time for gene therapy and the development of gene vaccines. Recently retroviral and lentiviral vectors have been used to generate tolerogenic dendritic cells, key professional antigen presenting cells that regulate immune responses. Thus, three main approaches have been undertaken to induce immunological tolerance; delivery of potent immunosuppressive cytokines and other molecules, modification of intracellular signalling pathways in dendritic cells, and de-targeting transgene expression from dendritic cells using microRNA technology. In this review we briefly describe retroviral and lentiviral vector biology, and their application to induce immunological tolerance.
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Affiliation(s)
- Inès Dufait
- Division of Infection and Immunity, Rayne Institute, University College London, 5 University Street, London, WC1E 6JF, UK
- Department of Physiology and Immunology, Medical School, Free University of Brussels, Laarbeeklaan 103, 1090 Jette, Belgium
| | - Therese Liechtenstein
- Division of Infection and Immunity, Rayne Institute, University College London, 5 University Street, London, WC1E 6JF, UK
| | - Alessio Lanna
- Division of Infection and Immunity, Rayne Institute, University College London, 5 University Street, London, WC1E 6JF, UK
| | - Christopher Bricogne
- Division of Infection and Immunity, Rayne Institute, University College London, 5 University Street, London, WC1E 6JF, UK
| | - Roberta Laranga
- Division of Infection and Immunity, Rayne Institute, University College London, 5 University Street, London, WC1E 6JF, UK
| | - Antonella Padella
- Division of Infection and Immunity, Rayne Institute, University College London, 5 University Street, London, WC1E 6JF, UK
| | - Karine Breckpot
- Department of Physiology and Immunology, Medical School, Free University of Brussels, Laarbeeklaan 103, 1090 Jette, Belgium
| | - David Escors
- Division of Infection and Immunity, Rayne Institute, University College London, 5 University Street, London, WC1E 6JF, UK
- *David Escors:
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Abstract
The PIT1/SLC20A1 protein, a well-described sodium/phosphate cotransporter and retrovirus receptor, has been identified recently as a modular of proliferation and apoptosis in vitro. The targeted deletion of the PIT1 gene in mice revealed a lethal phenotype due to severe anemia attributed to defects in liver development. However, the presence of immature erythroid cells associated with impaired maturation of the globin switch led us to investigate the role of PIT1 in hematopoietic development. In the present study, specific deletion of PIT1 in the hematopoietic system and fetal liver transplantation experiments demonstrated that anemia was associated with an erythroid cell- autonomous defect. Moreover, anemia was not due to RBC destruction but rather to maturation defects. Because Erythroid Krüppel-like Factor (EKLF)-knockout mice showed similar maturation defects, we investigated the functional link between PIT1 and EKLF. We demonstrated that EKLF increases PIT1 expression during RBC maturation by binding to its promoter in vivo and that shRNA-driven depletion of either PIT1 or EKLF impairs erythroid maturation of G1E cells in vitro, whereas reexpression of PIT1 in EKLF-depleted G1E cells partially restores erythroid maturation. This is the first demonstration of a physiologic involvement of PIT1 in erythroid maturation in vivo.
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Gattineni J, Baum M. Genetic disorders of phosphate regulation. Pediatr Nephrol 2012; 27:1477-87. [PMID: 22350303 PMCID: PMC3407352 DOI: 10.1007/s00467-012-2103-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 12/08/2011] [Accepted: 12/09/2011] [Indexed: 12/21/2022]
Abstract
Regulation of phosphate homeostasis is critical for many biological processes, and both hypophosphatemia and hyperphosphatemia can have adverse clinical consequences. Only a very small percentage (1%) of total body phosphate is present in the extracellular fluid, which is measured by routine laboratory assays and does not reflect total body phosphate stores. Phosphate is absorbed from the gastrointestinal tract via the transcellular route [sodium phosphate cotransporter 2b (NaPi2b)] and across the paracellular pathway. Approximately 85% of the filtered phosphate is reabsorbed from the kidney, predominantly in the proximal tubule, by NaPi2a and NaPi2c, which are present on the brush border membrane. Renal phosphate transport is tightly regulated. Dietary phosphate intake, parathyroid hormone (PTH), 1,25 (OH)2 vitamin D3, and fibroblast growth factor 23 (FGF23) are the principal regulators of phosphate reabsorption from the kidney. Recent advances in genetic techniques and animal models have identified many genetic disorders of phosphate homeostasis. Mutations in NaPi2a and NaPi2c; and hormonal dysregulation of PTH, FGF23, and Klotho, are primarily responsible for most genetic disorders of phosphate transport. The main focus of this educational review article is to discuss the genetic and clinical features of phosphate regulation disorders and provide understanding and treatment options.
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Affiliation(s)
- Jyothsna Gattineni
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75235-9063, USA.
| | - Michel Baum
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75235-9063 USA ,Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75235-9063 USA
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Forster IC, Hernando N, Biber J, Murer H. Phosphate transport kinetics and structure-function relationships of SLC34 and SLC20 proteins. CURRENT TOPICS IN MEMBRANES 2012. [PMID: 23177991 DOI: 10.1016/b978-0-12-394316-3.00010-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Transport of inorganic phosphate (P(i)) is mediated by proteins belonging to two solute carrier families (SLC20 and SLC34). Members of both families transport P(i) using the electrochemical gradient for Na(+). The role of the SLC34 members as essential players in mammalian P(i) homeostasis is well established, whereas that of SLC20 proteins is less well defined. The SLC34 family comprises the following three isoforms that preferentially cotransport divalent P(i) and are expressed in epithelial tissue: the renal NaPi-IIa and NaPi-IIc are responsible for reabsorbing P(i) in the proximal tubule, whereas NaPi-IIb is more ubiquitously expressed, including the small intestine, where it mediates dietary P(i) absorption. The SLC20 family comprises two members (PiT-1, PiT-2) that preferentially cotransport monovalent P(i) and are expressed in epithelial as well as nonepithelial tissue. The transport kinetics of members of both families have been characterized in detail using heterologous expression in Xenopus oocytes. For the electrogenic NaPi-IIa/b, and PiT-1,-2, conventional electrophysiological techniques together with radiotracer methods have been applied, as well as time-resolved fluorometric measurements that allow new insights into local conformational changes of the protein during the cotransport cycle. For the electroneutral NaPi-IIc, conventional tracer uptake and fluorometry have been used to elucidate its transport properties. The 3-D structures of these proteins remain unresolved and structure-function studies have so far concentrated on defining the topology and identifying sites of functional importance.
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Affiliation(s)
- Ian C Forster
- Institute of Physiology and Zurich Center for Integrative Human Physiology, University of Zurich, Winterthurerstrasse, Zurich, Switzerland.
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Escors D, Kochan G, Stephenson H, Breckpot K. Cell and Tissue Gene Targeting with Lentiviral Vectors. SPRINGERBRIEFS IN BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012. [PMCID: PMC7122860 DOI: 10.1007/978-3-0348-0402-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
One of the main advantages of using lentivectors is their capacity to transduce a wide range of cell types, independently from the cell cycle stage. However, transgene expression in certain cell types is sometimes not desirable, either because of toxicity, cell transformation, or induction of transgene-specific immune responses. In other cases, specific targeting of only cancerous cells within a tumor is sought after for the delivery of suicide genes. Consequently, great effort has been invested in developing strategies to control transgene delivery/expression in a cell/tissue-specific manner. These strategies can broadly be divided in three; particle pseudotyping (surface targeting), which entails modification of the envelope glycoprotein (ENV); transcriptional targeting, which utilizes cell-specific promoters and/or inducible promoters; and posttranscriptional targeting, recently applied in lentivectors by introducing sequence targets for cell-specific microRNAs. In this chapter we describe each of these strategies providing some illustrative examples.
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Affiliation(s)
- David Escors
- University College London, Rayne Building, 5 University Street, London, WC1E 6JF UK
| | - Grazyna Kochan
- Oxford Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building. Roosevelt Drive, Headington, Oxford, OX3 7DQ UK
| | - Holly Stephenson
- Institute of Child Health, University College London, Great Ormond Street, London, WC1N 3JH UK
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Murine leukemia viruses: objects and organisms. Adv Virol 2011; 2011:403419. [PMID: 22312342 PMCID: PMC3265304 DOI: 10.1155/2011/403419] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 07/25/2011] [Indexed: 01/12/2023] Open
Abstract
Murine leukemia viruses (MLVs) are among the simplest retroviruses. Prototypical gammaretroviruses encode only the three polyproteins that will be used in the assembly of progeny virus particles. These are the Gag polyprotein, which is the structural protein of a retrovirus particle, the Pol protein, comprising the three retroviral enzymes—protease, which catalyzes the maturation of the particle, reverse transcriptase, which copies the viral RNA into DNA upon infection of a new host cell, and integrase, which inserts the DNA into the chromosomal DNA of the host cell, and the Env polyprotein, which induces the fusion of the viral membrane with that of the new host cell, initiating infection. In general, a productive MLV infection has no obvious effect upon host cells. Although gammaretroviral structure and replication follow the same broad outlines as those of other retroviruses, we point out a number of significant differences between different retroviral genera.
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Human cytomegalovirus glycoprotein gO complexes with gH/gL, promoting interference with viral entry into human fibroblasts but not entry into epithelial cells. J Virol 2011; 85:11638-45. [PMID: 21880752 DOI: 10.1128/jvi.05659-11] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
A complex of five human cytomegalovirus virus (HCMV) proteins, gH, gL, UL128, UL130, and UL131 (gH/gL/UL128-131), is essential for virus entry into epithelial cells. We previously showed that gH/gL/UL128-131 expressed in epithelial cells interferes with subsequent HCMV entry into cells. There was no interference with only gH/gL or gB. We concluded that the expression of gH/gL/UL128-131 causes a mislocalization or downregulation of epithelial cell proteins that HCMV requires for entry. In contrast, gH/gL/UL128-131 expression in fibroblasts did not produce interference, suggesting a different mechanism for entry. Here, we show that the coexpression of another HCMV glycoprotein, gO, with gH/gL in human fibroblasts interferes with HCMV entry into fibroblasts but not epithelial cells. However, the coexpression of gO with gH/gL did not increase the cell surface expression level of gH/gL and did not enhance cell-cell fusion, a process that depends upon cell surface gH/gL. Instead, gO promoted the export of gH/gL from the endoplasmic reticulum (ER) and the accumulation of gH/gL in the trans-Golgi network. Thus, interference with gH/gL or gH/gL/gO, i.e., the mislocalization or blocking of entry mediators, occurs in cytoplasmic membranes and not in cell surface membranes of fibroblasts. Together, the results provide additional support for our hypotheses that epithelial cells express putative gH/gL/UL128-1331 receptors important for HCMV entry and that fibroblasts express distinct gH/gL receptors.
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Bøttger P, Pedersen L. Mapping of the minimal inorganic phosphate transporting unit of human PiT2 suggests a structure universal to PiT-related proteins from all kingdoms of life. BMC BIOCHEMISTRY 2011; 12:21. [PMID: 21586110 PMCID: PMC3126765 DOI: 10.1186/1471-2091-12-21] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Accepted: 05/17/2011] [Indexed: 11/10/2022]
Abstract
BACKGROUND The inorganic (Pi) phosphate transporter (PiT) family comprises known and putative Na(+)- or H(+)-dependent Pi-transporting proteins with representatives from all kingdoms. The mammalian members are placed in the outer cell membranes and suggested to supply cells with Pi to maintain house-keeping functions. Alignment of protein sequences representing PiT family members from all kingdoms reveals the presence of conserved amino acids and that bacterial phosphate permeases and putative phosphate permeases from archaea lack substantial parts of the protein sequence when compared to the mammalian PiT family members. Besides being Na(+)-dependent P(i) (NaP(i)) transporters, the mammalian PiT paralogs, PiT1 and PiT2, also are receptors for gamma-retroviruses. We have here exploited the dual-function of PiT1 and PiT2 to study the structure-function relationship of PiT proteins. RESULTS We show that the human PiT2 histidine, H(502), and the human PiT1 glutamate, E(70),--both conserved in eukaryotic PiT family members--are critical for P(i) transport function. Noticeably, human PiT2 H(502) is located in the C-terminal PiT family signature sequence, and human PiT1 E(70) is located in ProDom domains characteristic for all PiT family members.A human PiT2 truncation mutant, which consists of the predicted 10 transmembrane (TM) domain backbone without a large intracellular domain (human PiT2ΔR(254)-V(483)), was found to be a fully functional P(i) transporter. Further truncation of the human PiT2 protein by additional removal of two predicted TM domains together with the large intracellular domain created a mutant that resembles a bacterial phosphate permease and an archaeal putative phosphate permease. This human PiT2 truncation mutant (human PiT2ΔL(183)-V(483)) did also support P(i) transport albeit at very low levels. CONCLUSIONS The results suggest that the overall structure of the P(i)-transporting unit of the PiT family proteins has remained unchanged during evolution. Moreover, in combination, our studies of the gene structure of the human PiT1 and PiT2 genes (SLC20A1 and SLC20A2, respectively) and alignment of protein sequences of PiT family members from all kingdoms, along with the studies of the dual functions of the human PiT paralogs show that these proteins are excellent as models for studying the evolution of a protein's structure-function relationship.
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Affiliation(s)
- Pernille Bøttger
- Department of Molecular Biology, Aarhus University, C. F. Møllers Allé 3, Aarhus C, DK-8000, Denmark
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Khoshniat S, Bourgine A, Julien M, Weiss P, Guicheux J, Beck L. The emergence of phosphate as a specific signaling molecule in bone and other cell types in mammals. Cell Mol Life Sci 2011; 68:205-18. [PMID: 20848155 PMCID: PMC11114507 DOI: 10.1007/s00018-010-0527-z] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 08/02/2010] [Accepted: 08/31/2010] [Indexed: 02/07/2023]
Abstract
Although considerable advances in our understanding of the mechanisms of phosphate homeostasis and skeleton mineralization have recently been made, little is known about the initial events involving the detection of changes in the phosphate serum concentrations and the subsequent downstream regulation cascade. Recent data has strengthened a long-established hypothesis that a phosphate-sensing mechanism may be present in various organs. Such a phosphate sensor would detect changes in serum or local phosphate concentration and would inform the body, the local environment, or the individual cell. This suggests that phosphate in itself could represent a signal regulating multiple factors necessary for diverse biological processes such as bone or vascular calcification. This review summarizes findings supporting the possibility that phosphate represents a signaling molecule, particularly in bone and cartilage, but also in other tissues. The involvement of various signaling pathways (ERK1/2), transcription factors (Fra-1, Runx2) and phosphate transporters (PiT1, PiT2) is discussed.
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Affiliation(s)
- Solmaz Khoshniat
- Group STEP (Skeletal Tissue Engineering and Physiopathology), Centre for Osteoarticular and Dental Tissue Engineering (LIOAD), INSERM, U791, 44042 Nantes, France
- UFR Odontologie, Pres UNAM, 44042 Nantes, France
| | - Annabelle Bourgine
- Group STEP (Skeletal Tissue Engineering and Physiopathology), Centre for Osteoarticular and Dental Tissue Engineering (LIOAD), INSERM, U791, 44042 Nantes, France
- UFR Odontologie, Pres UNAM, 44042 Nantes, France
| | - Marion Julien
- Group STEP (Skeletal Tissue Engineering and Physiopathology), Centre for Osteoarticular and Dental Tissue Engineering (LIOAD), INSERM, U791, 44042 Nantes, France
- UFR Odontologie, Pres UNAM, 44042 Nantes, France
| | - Pierre Weiss
- Group STEP (Skeletal Tissue Engineering and Physiopathology), Centre for Osteoarticular and Dental Tissue Engineering (LIOAD), INSERM, U791, 44042 Nantes, France
- UFR Odontologie, Pres UNAM, 44042 Nantes, France
| | - Jérôme Guicheux
- Group STEP (Skeletal Tissue Engineering and Physiopathology), Centre for Osteoarticular and Dental Tissue Engineering (LIOAD), INSERM, U791, 44042 Nantes, France
- UFR Odontologie, Pres UNAM, 44042 Nantes, France
| | - Laurent Beck
- Growth and Signalling Research Center, INSERM, U845, 75015 Paris, France
- Faculté de Médecine, Centre de Recherche, INSERM U845, Université Paris Descartes, 156 Rue de Vaugirard, 75015 Paris, France
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Kosaka S, Tamauchi H, Terashima M, Maruyama H, Habu S, Kitasato H. IL-10 controls Th2-type cytokine production and eosinophil infiltration in a mouse model of allergic airway inflammation. Immunobiology 2010; 216:811-20. [PMID: 21257225 DOI: 10.1016/j.imbio.2010.12.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 12/11/2010] [Accepted: 12/14/2010] [Indexed: 12/31/2022]
Abstract
Interleukin-10 was originally described as a factor that inhibits cytokine production by murine Th1 clones. Recent studies have since shown that IL-10 can also downregulate Th2 clones and their production of IL-4 and IL-5. Because of its immuno-suppressive properties, IL-10 has been suggested as a potential therapy for allergic inflammation and asthma. However, the pathophysiological role of IL-10 in vivo has not been clearly elucidated. We investigated the effects of IL-10 administration on the production of IgE, cytokine and allergen-induced Th2 cytokine production as well as its effects on eosinophilic inflammation. We established GATA-3/TCR double transgenic (GATA-3/TCR-Tg) mice by crossing GATA-3 transgenic mice with ovalbumin (OVA)-specific TCR transgenic mice; these mice were then sensitized using an intraperitoneal injection of OVA adsorbed to alum and challenged with the intratracheal instillation of an allergen. When GATA-3/TCR-Tg mice sensitized with OVA and alum were injected with C57-IL-10 cells before OVA inhalation, the levels of IL-5, IL-13, and IL-4 decreased by 40-85% and number of eosinophils decreased by 70% (P<0.03) in the murine bronchoalveolar lavage fluid (BALF). These results suggest that IL-10 plays an important role downstream of the inflammatory cascade in the Th2 response to antigens and in the development of BALF eosinophilia and cytokine production in a murine model of asthma. These immunosuppressive properties in animal models indicate that IL-10 could be a potential clinical therapy for the treatment of allergic inflammation.
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Affiliation(s)
- Shinichiro Kosaka
- Department of Microbiology, Kitasato University Allied Health Science, Sagamihara, Kanagawa, Japan
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Abstract
Inherited diseases of renal phosphate handling lead to urinary phosphate wasting and depletion of total body phosphorus stores. Clinical sequelae of inherited disorders that are associated with increased urinary phosphate excretion are deleterious and can lead to abnormal skeletal growth and deformities. This Review describes hereditary disorders of renal phosphate wasting taking into account developments in our understanding of renal phosphate handling from the last decade. The cloning of genes involved in these disorders and further studies on their pathophysiological mechanisms have given important insights in to how phosphatonins, such as FGF-23, regulate renal phosphate reabsorption in health and disease. X-linked dominant hypophosphatemic rickets results from mutation of a metalloprotease (PHEX) that has an unidentified role in FGF-23 degradation. Mutation of an RXXR proteolytic cleavage site in FGF-23 prevents degradation and increases circulating levels of FGF-23 in autosomal dominant hypophosphatemic rickets. FGF-23 acts to remove sodium phosphate co-transporters from the luminal membrane of proximal tubular cells with resultant renal phosphate wasting. Loss of function mutations in genes encoding the transporters NaPi-IIc and NaPi-IIa also result in renal phosphate wasting and rickets.
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Abstract
Mutations in FLVCR2, a cell surface protein related by homology and membrane topology to the heme exporter/retroviral receptor FLVCR1, have recently been associated with Fowler syndrome, a vascular disorder of the brain. We previously identified FLVCR2 to function as a receptor for FY981 feline leukemia virus (FeLV). However, the cellular function of FLVCR2 remains unresolved. Here, we report the cellular function of FLVCR2 as an importer of heme, based on the following observations. First, FLVCR2 binds to hemin-conjugated agarose, and binding is competed by free hemin. Second, mammalian cells and Xenopus laevis oocytes expressing FLVCR2 display enhanced heme uptake. Third, heme import is reduced after the expression of FLVCR2-specific small interfering RNA (siRNA) or after the binding of the FY981 FeLV envelope protein to the FLVCR2 receptor. Finally, cells overexpressing FLVCR2 are more sensitive to heme toxicity, a finding most likely attributable to enhanced heme uptake. Tissue expression analysis indicates that FLVCR2 is expressed in a broad range of human tissues, including liver, placenta, brain, and kidney. The identification of a cellular function for FLVCR2 will have important implications in elucidating the pathogenic mechanisms of Fowler syndrome and of phenotypically associated disorders.
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Manning E, Pham S, Li S, Vazquez-Padron RI, Mathew J, Ruiz P, Salgar SK. Interleukin-10 delivery via mesenchymal stem cells: a novel gene therapy approach to prevent lung ischemia-reperfusion injury. Hum Gene Ther 2010; 21:713-27. [PMID: 20102275 DOI: 10.1089/hum.2009.147] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Ischemia-reperfusion (IR) injury is an important cause of primary graft failure in lung transplantation. In this study, viral interleukin-10 (vIL-10)-engineered mesenchymal stem cells (MSCs) were tested for their ability to prevent lung IR injury. Bone marrow-derived MSCs were transduced with rvIL-10-retrovirus. After 120 min of warm left lung ischemia, rats received approximately 15 x 10(6) vIL-10-engineered MSCs (MSC-vIL-10), empty vector-engineered MSCs (MSC-vec), or saline intravenously. Mean blood oxygenation (PaO(2)/FiO(2) ratio, mmHg) was measured at 4 hr, 24 hr, 72 hr, and 7 days. As early as 4 hr post-IR injury with MSC-vIL-10 treatment, blood oxygenation was significantly (p < 0.05) improved (319 +/- 94; n = 7) compared with untreated (saline) controls (63 +/- 19; n = 6). At 24 hr post-IR injury, in the MSC-vIL-10-treated group there was a further increase in blood oxygenation (353 +/- 105; n = 10) compared with the MSC-vec group (138 +/- 86; n = 9) and saline group (87 +/- 39; n = 10). By 72 hr, oxygenation reached normal (475 +/- 55; n = 9) in the MSC-vIL-10-treated group but not in the saline-treated and MSC-vec-treated groups. At 4 hr after IR injury, lungs with MSC-vIL10 treatment had a lower (p < 0.05) injury score (0.9 +/- 0.4) compared with lungs of the untreated (saline) group (2.5 +/- 1.4) or MSC-vec-treated group (2 +/- 0.4). Lung microvascular permeability and wet-to-dry weight ratios were markedly lower in the MSC-vIL10 group compared with untreated (saline) controls. ISOL (in situ oligonucleotide ligation for DNA fragmentation detection) and caspase-3 staining demonstrated significantly (p < 0.05) fewer apoptotic cells in MSC-vIL10-treated lungs. Animals that received MSC-vIL10 therapy had fewer (p < 0.05) CD4(+) and CD8(+) T cells in bronchoalveolar lavage fluid compared with untreated control animals. A therapeutic strategy using vIL-10-engineered MSCs to prevent IR injury in lung transplantation seems promising.
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Affiliation(s)
- Eddie Manning
- Interdisciplinary Stem Cell Institute, Department of Surgery, University of Miami Miller School of Medicine, 1600 NW 10th Avenue, Miami, FL 33136, USA
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Beck L, Leroy C, Beck-Cormier S, Forand A, Salaün C, Paris N, Bernier A, Ureña-Torres P, Prié D, Ollero M, Coulombel L, Friedlander G. The phosphate transporter PiT1 (Slc20a1) revealed as a new essential gene for mouse liver development. PLoS One 2010; 5:e9148. [PMID: 20161774 PMCID: PMC2818845 DOI: 10.1371/journal.pone.0009148] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 01/12/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND PiT1 (or SLC20a1) encodes a widely expressed plasma membrane protein functioning as a high-affinity Na(+)-phosphate (Pi) cotransporter. As such, PiT1 is often considered as a ubiquitous supplier of Pi for cellular needs regardless of the lack of experimental data. Although the importance of PiT1 in mineralizing processes have been demonstrated in vitro in osteoblasts, chondrocytes and vascular smooth muscle cells, in vivo evidence is missing. METHODOLOGY/PRINCIPAL FINDINGS To determine the in vivo function of PiT1, we generated an allelic series of PiT1 mutations in mice by combination of wild-type, hypomorphic and null PiT1 alleles expressing from 100% to 0% of PiT1. In this report we show that complete deletion of PiT1 results in embryonic lethality at E12.5. PiT1-deficient embryos display severely hypoplastic fetal livers and subsequent reduced hematopoiesis resulting in embryonic death from anemia. We show that the anemia is not due to placental, yolk sac or vascular defects and that hematopoietic progenitors have no cell-autonomous defects in proliferation and differentiation. In contrast, mutant fetal livers display decreased proliferation and massive apoptosis. Animals carrying two copies of hypomorphic PiT1 alleles (resulting in 15% PiT1 expression comparing to wild-type animals) survive at birth but are growth-retarded and anemic. The combination of both hypomorphic and null alleles in heterozygous compounds results in late embryonic lethality (E14.5-E16.5) with phenotypic features intermediate between null and hypomorphic mice. In the three mouse lines generated we could not evidence defects in early skeleton formation. CONCLUSION/SIGNIFICANCE This work is the first to illustrate a specific in vivo role for PiT1 by uncovering it as being a critical gene for normal developmental liver growth.
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MESH Headings
- Animals
- Apoptosis
- Cell Count
- Cell Proliferation
- Cells, Cultured
- Embryo, Mammalian/abnormalities
- Embryo, Mammalian/metabolism
- Erythrocytes/metabolism
- Female
- Gene Expression Regulation, Developmental
- Genes, Essential
- Genotype
- Hematopoietic Stem Cells/metabolism
- Liver/cytology
- Liver/embryology
- Liver/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred Strains
- Mice, Knockout
- Mutation
- Reverse Transcriptase Polymerase Chain Reaction
- Sodium-Phosphate Cotransporter Proteins, Type III/deficiency
- Sodium-Phosphate Cotransporter Proteins, Type III/genetics
- Time Factors
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Affiliation(s)
- Laurent Beck
- INSERM, U845, Centre de Recherche Croissance et Signalisation, Paris, France.
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Jin C, Zoidis E, Ghirlanda C, Schmid C. Dexamethasone and cyclic AMP regulate sodium phosphate cotransporter (NaPi-IIb and Pit-1) mRNA and phosphate uptake in rat alveolar type II epithelial cells. Lung 2009; 188:51-61. [PMID: 19806400 DOI: 10.1007/s00408-009-9183-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Accepted: 09/14/2009] [Indexed: 11/25/2022]
Abstract
Alveolar epithelial type II (AT II) cells need phosphate (Pi) for surfactant synthesis. The Na-dependent (Na(d)) Pi transporters NaPi-IIb and Pit-1 are expressed in lung, but their expression, regulation, and function in AT II cells remain unclear. We studied NaPi-IIb and Pit-1 mRNA expression in cultured AT II cells isolated from adult rat lung, their regulation by agents known to enhance surfactant production, dexamethasone (dex) and dibutyryl cyclic AMP (cAMP), and the effects of dex and cAMP on Na(d) Pi uptake by this cell type. By Northern analysis, cultured AT II cells expressed both NaPi-IIb (4.8 and 4.0 kb) and Pit-1 (4.3 kb) mRNA. Treatment with 100 nmol/l dex for 24 h decreased the expression of both mRNAs (to 0.48 +/- 0.06 and 0.77 +/- 0.05, respectively, as compared to control), while 0.1 mmol/l cAMP stimulated NaPi-IIb (1.94 +/- 0.22) but not Pit-1 mRNA (0.90 +/- 0.05, compared to vehicle-treated cells). NaPi-IIb and Pit-1 proteins could not be identified by western analysis of plasma membrane preparations of cultured AT II cells. AT II cells take up Pi in a Na(d) manner. Uptake was slightly (to 0.78-fold of the control) decreased by 100 nmol/l dex but not affected by 0.1 mmol/l cAMP treatment. Although NaPi-IIb mRNA expression was maintained to some extent by AT II cells kept in primary culture, Pi uptake was more closely related to Pit-1 mRNA expression.
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Affiliation(s)
- Chengluo Jin
- Division of Endocrinology and Diabetology, Department of Internal Medicine, University Hospital, 8091, Zurich, Switzerland
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Farrell KB, Tusnady GE, Eiden MV. New structural arrangement of the extracellular regions of the phosphate transporter SLC20A1, the receptor for gibbon ape leukemia virus. J Biol Chem 2009; 284:29979-87. [PMID: 19717569 DOI: 10.1074/jbc.m109.022566] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Infection of a host cell by a retrovirus requires an initial interaction with a cellular receptor. For numerous gammaretroviruses, such as the gibbon ape leukemia virus, woolly monkey virus, feline leukemia virus subgroup B, feline leukemia virus subgroup T, and 10A1 murine leukemia virus, this receptor is the human type III sodium-dependent inorganic phosphate transporter, SLC20A1, formerly known as PiT1. Understanding the critical receptor functionalities and interactions with the virus that lead to successful infection requires that we first know the surface structure of the cellular receptor. Previous molecular modeling from the protein sequence, and limited empirical data, predicted a protein with 10 transmembrane helices. Here we undertake the biochemical approach of substituted cysteine accessibility mutagenesis to resolve the topology of this receptor in live cells. We discover that there are segments of the protein that are unexpectedly exposed to the outside milieu. By using information determined by substituted cysteine accessibility mutagenesis to set constraints in HMMTOP, a hidden Markov model-based transmembrane topology prediction method, we now propose a comprehensive topological model for SLC20A1, a transmembrane protein with 12 transmembrane helices and 7 extracellular regions, that varies from previous models and should permit approaches that define both virus interaction and transport function.
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Affiliation(s)
- Karen B Farrell
- Section on Molecular Virology, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, Bethesda, Maryland 20892, USA
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Marcucci KT, Argaw T, Wilson CA, Salomon DR. Identification of two distinct structural regions in a human porcine endogenous retrovirus receptor, HuPAR2, contributing to function for viral entry. Retrovirology 2009; 6:3. [PMID: 19144196 PMCID: PMC2630988 DOI: 10.1186/1742-4690-6-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 01/14/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Of the three subclasses of Porcine Endogenous Retrovirus (PERV), PERV-A is able to infect human cells via one of two receptors, HuPAR1 or HuPAR2. Characterizing the structure-function relationships of the two HuPAR receptors in PERV-A binding and entry is important in understanding receptor-mediated gammaretroviral entry and contributes to evaluating the risk of zoonosis in xenotransplantation. RESULTS Chimeras of the non-permissive murine PAR and the permissive HuPAR2, which scanned the entire molecule, revealed that the first 135 amino acids of HuPAR2 are critical for PERV-A entry. Within this critical region, eighteen single residue differences exist. Site-directed mutagenesis used to map single residues confirmed the previously identified L109 as a binding and infectivity determinant. In addition, we identified seven residues contributing to the efficiency of PERV-A entry without affecting envelope binding, located in multiple predicted structural motifs (intracellular, extracellular and transmembrane). We also show that expression of HuPAR2 in a non-permissive cell line results in an average 11-fold higher infectivity titer for PERV-A compared to equal expression of HuPAR1, although PERV-A envelope binding is similar. Chimeras between HuPAR-1 and -2 revealed that the region spanning amino acids 152-285 is responsible for the increase of HuPAR2. Fine mapping of this region revealed that the increased receptor function required the full sequence rather than one or more specific residues. CONCLUSION HuPAR2 has two distinct structural regions. In one region, a single residue determines binding; however, in both regions, multiple residues influence receptor function for PERV-A entry.
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Affiliation(s)
- Katherine T Marcucci
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
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McElroy M, Hayashi K, Garmy-Susini B, Kaushal S, Varner JA, Moossa A, Hoffman RM, Bouvet M. Fluorescent LYVE-1 antibody to image dynamically lymphatic trafficking of cancer cells in vivo. J Surg Res 2009; 151:68-73. [PMID: 18599080 PMCID: PMC2628480 DOI: 10.1016/j.jss.2007.12.769] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Revised: 11/12/2007] [Accepted: 12/06/2007] [Indexed: 11/19/2022]
Abstract
BACKGROUND The lymphatic system is a major route for cancer cell dissemination, and a potential target for antitumor therapy. Despite ongoing interest in this area of research, the real-time behavior of cancer cells trafficking in the lymphatic system is poorly understood due to lack of appropriate tools to image this process. MATERIALS AND METHODS We have used monoclonal-antibody and fluorescence technology to color-code lymphatic vessels and the cancer cells inside them in a living animal. Monoclonal anti-mouse LYVE-1 antibody was conjugated to a green fluorophore and delivered to the lymphatic system of a nude mouse, allowing imaging of mouse lymphatics. Tumor cells engineered to express red fluorescent protein were then imaged traveling within the labeled lymphatics in real time. RESULTS AlexaFluor-labeled monoclonal anti-mouse LYVE-1 created a durable signal with clear delineation of lymphatic architecture. The duration of fluorescent signal after conjugated LYVE-1 delivery was far superior to that of fluorescein isothiocyanate-dextran or control fluorophore-conjugated IgG. Tumor cells engineered to express red fluorescent protein delivered to the inguinal lymph node enabled real-time tracking of tumor cell movement within the green fluorescent-labeled lymphatic vessels. CONCLUSIONS This technology offers a powerful tool for the in vivo study of real-time trafficking of tumor cells within lymphatic vessels, for the deposition of the tumor cells in lymph nodes, as well as for screening of potential antitumor lymphatic therapies.
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Affiliation(s)
- Michele McElroy
- Department of Surgery, University of California, San Diego, CA
| | - Katsuhiro Hayashi
- Department of Surgery, University of California, San Diego, CA
- AntiCancer, Inc., San Diego, CA
| | | | | | | | - A.R. Moossa
- Department of Surgery, University of California, San Diego, CA
| | - Robert M. Hoffman
- Department of Surgery, University of California, San Diego, CA
- AntiCancer, Inc., San Diego, CA
| | - Michael Bouvet
- Department of Surgery, University of California, San Diego, CA
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Abstract
Up to 10% of the mouse genome is comprised of endogenous retrovirus (ERV) sequences, and most represent the remains of ancient germ line infections. Our knowledge of the three distinct classes of ERVs is inversely correlated with their copy number, and their characterization has benefited from the availability of divergent wild mouse species and subspecies, and from ongoing analysis of the Mus genome sequence. In contrast to human ERVs, which are nearly all extinct, active mouse ERVs can still be found in all three ERV classes. The distribution and diversity of ERVs has been shaped by host-virus interactions over the course of evolution, but ERVs have also been pivotal in shaping the mouse genome by altering host genes through insertional mutagenesis, by adding novel regulatory and coding sequences, and by their co-option by host cells as retroviral resistance genes. We review mechanisms by which an adaptive coexistence has evolved. (Part of a multi-author review).
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Affiliation(s)
- C. Stocking
- Heinrich-Pette-Institute, Martinistrasse 52, 20251 Hamburg, Germany
| | - C. A. Kozak
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 4 Center Drive MSC 0460, Bethesda, Maryland, 20892-0460 USA
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An equine infectious anemia virus variant superinfects cells through novel receptor interactions. J Virol 2008; 82:9425-32. [PMID: 18667522 DOI: 10.1128/jvi.01142-08] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Wild-type strains of equine infectious anemia virus (EIAV) prevent superinfection of previously infected cells. A variant strain of virus that spontaneously arose during passage, EIAV(vMA-1c), can circumvent this mechanism in some cells, such as equine dermis (ED) cells, but not in others, such as equine endothelial cells. EIAV(vMA-1c) superinfection of ED cells results in a buildup of unintegrated viral DNA and rapid killing of the cell monolayer. Here, we examined the mechanism of resistance that is used by EIAV to prevent superinfection and explored the means by which EIAV(vMA-1c) overcomes this restriction. We found that the cellular receptor used by EIAV, equine lentivirus receptor 1 (ELR1), remains on the surface of cells chronically infected with EIAV, suggesting that wild-type EIAV interferes with superinfection by masking ELR1. The addition of soluble wild-type SU protein to the medium during infection blocked infection by wild-type strains of virus, implicating SU as the viral protein responsible for interfering with virion entry into previously infected cells. Additionally, interference of wild-type EIAV binding to ELR1 by the addition of either anti-ELR1 antibodies or the ELR1 ectodomain prevented entry of the wild-type strains of EIAV into two permissive cell populations. Many of these same interference treatments prevented EIAV(vMA-1c) infection of endothelial cells but only modestly affected the ability of EIAV(vMA-1c) to enter and kill previously infected ED cells. These findings indicate that EIAV(vMA-1c) retains the ability to use ELR1 for entry and suggest that this virus can interact with an additional, unidentified receptor to superinfect ED cells.
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41
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Identification of the myelin protein plasmolipin as the cell entry receptor for Mus caroli endogenous retrovirus. J Virol 2008; 82:6862-8. [PMID: 18463156 DOI: 10.1128/jvi.00397-08] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The Asian wild mouse species Mus caroli harbors an endogenous retrovirus (McERV) that is closely related to but distinct from the endogenous retrovirus family defined by the Mus dunni endogenous virus and the Mus musculus endogenous retrovirus. McERV could infect some cell types from humans, dogs, and rats, but not all, and did not infect any mouse cell line tested. Because of its interesting host range and proposed ancestral relationship to primate retroviruses and because none of the entry receptors for this family of retroviruses had been identified, we began a search for the McERV receptor. We determined the chromosomal location of the receptor gene in the human genome by phenotypic screening of the G3 human-hamster radiation hybrid cell line panel and confirmed the localization by assaying for receptor activity conferred by bacterial artificial chromosome (BAC) clones spanning the region. We next localized the gene more precisely in one positive BAC by assaying for receptor activity following BAC digestion with several restriction enzymes that cleaved different sets of genes, and we confirmed that the final candidate gene, plasmolipin (PLLP; TM4SF11), is the novel receptor by showing that the expression of the human PLLP cDNA renders hamster and mouse cells susceptible to McERV infection. PLLP functions as a voltage-dependent potassium ion channel and is expressed primarily in kidney and brain, helping to explain the limited range of cell types that McERV can infect. Interestingly, mouse PLLP also functioned well as a receptor for McERV but was simply not expressed in the mouse cell types that we originally tested.
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42
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Miyazawa M, Tsuji-Kawahara S, Kanari Y. Host genetic factors that control immune responses to retrovirus infections. Vaccine 2008; 26:2981-96. [PMID: 18255203 DOI: 10.1016/j.vaccine.2008.01.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2007] [Revised: 01/01/2008] [Accepted: 01/04/2008] [Indexed: 12/30/2022]
Abstract
Several host genes control retroviral replication and pathogenesis. These include genes that directly affect the replication of retroviruses in target cells and those that control the host immune responses to the viral antigens. Host genetic factors that affect retroviral replication and immune responses to the viral antigens have been best studied in mouse models of Friend leukemia virus (FV) infection. Several genes located within the major histocompatibility complex (MHC), along with a separate gene not linked to the MHC, influence the host immune responses to FV antigens. The latter, the Rfv3, regulates the production of virus-neutralizing antibodies, and thus affects the duration of viremia. T-cell responses to the viral epitopes are controlled by MHC class I and class II genotypes, and both CD8(+) and CD4(+) T-cells are required for spontaneous immune resistance to FV infection. When CD4(+) T-helper cells are efficiently primed with a viral epitope, however, CD8(+) T-cells are not required for immune protection against FV infection, while B cells are absolutely required. There are individuals who possess human immunodeficiency virus type 1 (HIV-1)-reactive IgA antibodies in their mucosal secretions and show strong T-cell responses to HIV-1 antigens, even though they are negative for HIV-1 genome and HIV-1-reactive serum IgG. These HIV-1-exposed but uninfected individuals rarely possess resistance-associated alleles at known AIDS-restricting loci such as CCR5Delta32. Recent genetic analyses have indicated that a large proportion of such exposed but uninfected individuals may share a common genetic background.
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Affiliation(s)
- Masaaki Miyazawa
- Department of Immunology, Kinki University School of Medicine, Osaka 589-0023, Japan.
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43
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Al-Saeedi F. Role of 99mTc-(V)DMSA in Detecting Tumor Cell Proliferation. ANALYTICAL CHEMISTRY INSIGHTS 2007. [DOI: 10.4137/117739010700200001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Pentavalent technetium-99m dimercaptosuccinic acid (99mTc-(V)DMSA) is a tumor-seeking agent which was introduced to evaluate, image, and manage many types of cancers. In this review, the beginning of, and the most recent applications of using this agent was appraised. The relation with tumor cell detection and proliferation was reported and several mechanisms of uptake of 99mTc-(V)DMSA in tumor cells are described.
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Affiliation(s)
- Fatma Al-Saeedi
- Department of Nuclear Medicine, Faculty of Medicine, Kuwait University, Kuwait
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44
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Al-Saeedi F. Role of 99mTc-(V)DMSA in detecting tumor cell proliferation. ANALYTICAL CHEMISTRY INSIGHTS 2007; 2:81-3. [PMID: 19662181 PMCID: PMC2716817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Pentavalent technetium-99m dimercaptosuccinic acid ((99m)Tc-(V)DMSA) is a tumor-seeking agent which was introduced to evaluate, image, and manage many types of cancers. In this review, the beginning of, and the most recent applications of using this agent was appraised. The relation with tumor cell detection and proliferation was reported and several mechanisms of uptake of (99m)Tc-(V)DMSA in tumor cells are described.
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Affiliation(s)
- Fatma Al-Saeedi
- Correspondence: Dr. Fatma Al-Saeedi, Department of Nuclear Medicine, Faculty of Medicine, Kuwait University, P.O. Box: 24923, postal code/zip 13110, Safat, Kuwait. Tel: 00965-4986245; Fax: 00965-5338936;
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45
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Tan PH, Xue SA, Wei B, Holler A, Voss RH, George AJT. Changing viral tropism using immunoliposomes alters the stability of gene expression: implications for viral vector design. Mol Med 2007. [PMID: 17592557 DOI: 10.2119/2006-00052.tan] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many strategies for redirecting the tropism of murine Moloney leukemia virus (MMLV) have been described. Preformed virion-liposome complexes, termed virosomes, have been reported to be relatively stable. Virosomes mediate envelope-independent transduction that allows efficient superinfection of resistant cell lines; however, virosome-mediated transduction behaves in a non-target-specific manner. We developed a novel method using antibodies to direct MMLV to vascular endothelium. We have given the term immunovirosomes to the complexes formed between viruses, liposomes, and antibodies. These immunovirosomes improve the transduction efficiency of the viruses and alter their tropism. We have shown improved transduction when immunovirosomes were targeted at the endocytic receptors CD71 and CD62E/P and rather less good delivery when targeted at CD106. The enhancement of the transduction efficiency was transient, however, suggesting that rerouting the entry pathway of viruses alters the expression properties of the viruses.
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Affiliation(s)
- Peng H Tan
- Department of Immunology, Division of Medicine, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.
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46
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Tan PH, Xue SA, Wei B, Holler A, Voss RH, George AJT. Changing viral tropism using immunoliposomes alters the stability of gene expression: implications for viral vector design. MOLECULAR MEDICINE (CAMBRIDGE, MASS.) 2007; 13:216-26. [PMID: 17592557 PMCID: PMC1892767 DOI: 10.2119/2006–00052.tan] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/02/2006] [Accepted: 02/05/2007] [Indexed: 11/06/2022]
Abstract
Many strategies for redirecting the tropism of murine Moloney leukemia virus (MMLV) have been described. Preformed virion-liposome complexes, termed virosomes, have been reported to be relatively stable. Virosomes mediate envelope-independent transduction that allows efficient superinfection of resistant cell lines; however, virosome-mediated transduction behaves in a non-target-specific manner. We developed a novel method using antibodies to direct MMLV to vascular endothelium. We have given the term immunovirosomes to the complexes formed between viruses, liposomes, and antibodies. These immunovirosomes improve the transduction efficiency of the viruses and alter their tropism. We have shown improved transduction when immunovirosomes were targeted at the endocytic receptors CD71 and CD62E/P and rather less good delivery when targeted at CD106. The enhancement of the transduction efficiency was transient, however, suggesting that rerouting the entry pathway of viruses alters the expression properties of the viruses.
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Affiliation(s)
- Peng H Tan
- Department of Immunology, Division of Medicine, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.
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47
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Engels B, Uckert W. Redirecting T lymphocyte specificity by T cell receptor gene transfer – A new era for immunotherapy. Mol Aspects Med 2007; 28:115-42. [PMID: 17307249 DOI: 10.1016/j.mam.2006.12.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Accepted: 12/18/2006] [Indexed: 12/16/2022]
Abstract
The therapeutic efficacy of adoptively transferred cytotoxic T lymphocytes (CTL) has been demonstrated in clinical trials for the treatment of chronic myelogenous leukemia, cytomegalovirus-mediated disease, and Epstein-Barr virus-positive B cell lymphomas. It is however limited by the difficulty of generating sufficient amounts of CTLs in vitro, especially for the treatment of solid tumors. Recent gene therapy approaches, including two clinical trials, successfully apply genetic engineering of T cell specificity by T cell receptor (TCR) gene transfer. In this review we want to elucidate several principles of the redirection of T cell specificity. We cover basic aspects of retroviral gene transfer, regarding transduction efficacy and transgene expression levels. It was demonstrated that the number of TCR molecules on a T cell is important for its function. Therefore, an efficient transfer system that yields high transduction efficiency and strong and stable transgene expression is a prerequisite to achieve effector function by redirected T cells. Furthermore, we consider more recent aspects of T cell specificity engineering. These include the possibility of co-transferring coreceptors to create for example functional T helper cells by engrafting CD4(+) T cells with a MHC class I restricted TCR and the CD8 coreceptor and vice versa. Also, risks related to the adoptive transfer of TCR gene-modified T cells and possible safety mechanisms are discussed. Finally, we summarize recent findings describing transferred TCRs capable of displacing endogenous TCRs from the cell surface.
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Affiliation(s)
- Boris Engels
- Humboldt-University Berlin, Institute of Biology, Department of Molecular Cell Biology and Gene Therapy, Robert-Rössle-Strasse 10, D-13092 Berlin, Germany
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48
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Rodenburg M, Fischer M, Engelmann A, Harbers SO, Ziegler M, Löhler J, Stocking C. Importance of receptor usage, Fli1 activation, and mouse strain for the stem cell specificity of 10A1 murine leukemia virus leukemogenicity. J Virol 2006; 81:732-42. [PMID: 17079317 PMCID: PMC1797452 DOI: 10.1128/jvi.01430-06] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Murine leukemia viruses (MuLV) induce leukemia through a multistage process, a critical step being the activation of oncogenes through provirus integration. Transcription elements within the long terminal repeats (LTR) are prime determinants of cell lineage specificity; however, the influence of other factors, including the Env protein that modulates cell tropism through receptor recognition, has not been rigorously addressed. The ability of 10A1-MuLV to use both PiT1 and PiT2 receptors has been implicated in its induction of blast cell leukemia. Here we show that restricting receptor usage of 10A1-MuLV to PiT2 results in loss of blast cell transformation capacity. However, the pathogenicity was unaltered when the env gene is exchanged with Moloney MuLV, which uses the Cat1 receptor. Significantly, the leukemic blasts express erythroid markers and consistently contain proviral integrations in the Fli1 locus, a target of Friend MuLV (F-MuLV) during erythroleukemia induction. Furthermore, an NB-tropic variant of 10A1 was unable to induce blast cell leukemia in C57BL/6 mice, which are also resistant to F-MuLV transformation. We propose that 10A1- and F-MuLV actually induce identical (erythro)blastic leukemia by a mechanism involving Fli1 activation and cooperation with inherent genetic mutations in susceptible mouse strains. Furthermore, we demonstrate that deletion of the Icsbp tumor suppressor gene in C57BL/6 mice is sufficient to confer susceptibility to 10A1-MuLV leukemia induction but with altered specificity. In summary, we validate the significance of the env gene in leukemia specificity and underline the importance of a complex interplay of cooperating oncogenes and/or tumor suppressors in determining the pathogenicity of MuLV variants.
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MESH Headings
- Animals
- Cells, Cultured
- Fibroblasts
- Gene Products, env/genetics
- Gene Products, env/metabolism
- Hematopoietic Stem Cells/pathology
- Hematopoietic Stem Cells/virology
- Leukemia Virus, Murine/genetics
- Leukemia Virus, Murine/metabolism
- Leukemia Virus, Murine/pathogenicity
- Leukemia, Experimental/pathology
- Leukemia, Experimental/virology
- Mice
- Mice, Inbred C57BL
- Proto-Oncogene Protein c-fli-1/genetics
- Proto-Oncogene Protein c-fli-1/metabolism
- Receptors, Virus/metabolism
- Retroviridae Infections/pathology
- Retroviridae Infections/virology
- Species Specificity
- Tumor Virus Infections/pathology
- Tumor Virus Infections/virology
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49
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Tsurutani N, Yasuda J, Yamamoto N, Choi BI, Kadoki M, Iwakura Y. Nuclear import of the preintegration complex is blocked upon infection by human immunodeficiency virus type 1 in mouse cells. J Virol 2006; 81:677-88. [PMID: 17079325 PMCID: PMC1797461 DOI: 10.1128/jvi.00870-06] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mouse cells do not support human immunodeficiency virus type 1 (HIV-1) replication because of host range barriers at steps including virus entry, transcription, RNA splicing, polyprotein processing, assembly, and release. The exact mechanisms for the suppression, however, are not completely understood. To elucidate further the barriers against HIV-1 replication in mouse cells, we analyzed the replication of the virus in lymphocytes from human CD4/CXCR4 transgenic mice. Although primary splenocytes and thymocytes allowed the entry and reverse transcription of HIV-1, the integration efficiency of the viral DNA was greatly reduced in these cells relative to human peripheral blood mononuclear cells, suggesting an additional block(s) before or at the point of host chromosome integration of the viral DNA. Preintegration processes were further analyzed using HIV-1 pseudotyped viruses. The reverse transcription step of HIV-1 pseudotyped with the envelope of murine leukemia virus or vesicular stomatitis virus glycoprotein was efficiently supported in both human and mouse cells, but nuclear import of the preintegration complex (PIC) of HIV-1 was blocked in mouse cells. We found that green fluorescent protein (GFP)-labeled HIV-1 integrase, which is known to be important in the nuclear localization of the PIC, could not be imported into the nucleus of mouse cells, in contrast to human cells. On the other hand, GFP-Vpr localized exclusively to the nuclei of both mouse and human cells. These observations suggest that, due to the dysfunction of integrase, the nuclear localization of PIC is suppressed in mouse cells.
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Affiliation(s)
- Naomi Tsurutani
- Center for Experimental Medicine, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Tokyo 108-8639, Japan
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50
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Bøttger P, Hede SE, Grunnet M, Høyer B, Klaerke DA, Pedersen L. Characterization of transport mechanisms and determinants critical for Na+-dependent Pi symport of the PiT family paralogs human PiT1 and PiT2. Am J Physiol Cell Physiol 2006; 291:C1377-87. [PMID: 16790504 DOI: 10.1152/ajpcell.00015.2006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The general phosphate need in mammalian cells is accommodated by members of the P(i) transport (PiT) family (SLC20), which use either Na(+) or H(+) to mediate inorganic phosphate (P(i)) symport. The mammalian PiT paralogs PiT1 and PiT2 are Na(+)-dependent P(i) (NaP(i)) transporters and are exploited by a group of retroviruses for cell entry. Human PiT1 and PiT2 were characterized by expression in Xenopus laevis oocytes with (32)P(i) as a traceable P(i) source. For PiT1, the Michaelis-Menten constant for P(i) was determined as 322.5 +/- 124.5 microM. PiT2 was analyzed for the first time and showed positive cooperativity in P(i) uptake with a half-maximal activity constant for P(i) of 163.5 +/- 39.8 microM. PiT1- and PiT2-mediated Na(+)-dependent P(i) uptake functions were not significantly affected by acidic and alkaline pH and displayed similar Na(+) dependency patterns. However, only PiT2 was capable of Na(+)-independent P(i) transport at acidic pH. Study of the impact of divalent cations Ca(2+) and Mg(2+) revealed that Ca(2+) was important, but not critical, for NaP(i) transport function of PiT proteins. To gain insight into the NaP(i) cotransport function, we analyzed PiT2 and a PiT2 P(i) transport knockout mutant using (22)Na(+) as a traceable Na(+) source. Na(+) was transported by PiT2 even without P(i) in the uptake medium and also when P(i) transport function was knocked out. This is the first time decoupling of P(i) from Na(+) transport has been demonstrated for a PiT family member. Moreover, the results imply that putative transmembrane amino acids E(55) and E(575) are responsible for linking P(i) import to Na(+) transport in PiT2.
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Affiliation(s)
- Pernille Bøttger
- Department of Molecular Biology, Institute of Clinical Medicine, University of Aarhus, Aarhus, Denmark
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