101
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Ko AR, Jin DK, Cho SY, Park SW, Przybylska M, Yew NS, Cheng SH, Kim JS, Kwak MJ, Kim SJ, Sohn YB. AAV8-mediated expression of N-acetylglucosamine-1-phosphate transferase attenuates bone loss in a mouse model of mucolipidosis II. Mol Genet Metab 2016; 117:447-55. [PMID: 26857995 DOI: 10.1016/j.ymgme.2016.02.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 02/02/2016] [Accepted: 02/02/2016] [Indexed: 11/22/2022]
Abstract
Mucolipidoses II and III (ML II and ML III) are lysosomal disorders in which the mannose 6-phosphate recognition marker is absent from lysosomal hydrolases and other glycoproteins due to mutations in GNPTAB, which encodes two of three subunits of the heterohexameric enzyme, N-acetylglucosamine-1-phosphotransferase. Both disorders are caused by the same gene, but ML II represents the more severe phenotype. Bone manifestations of ML II include hip dysplasia, scoliosis, rickets and osteogenesis imperfecta. In this study, we sought to determine whether a recombinant adeno-associated viral vector (AAV2/8-GNPTAB) could confer high and prolonged gene expression of GNPTAB and thereby influence the pathology in the cartilage and bone tissue of a GNPTAB knock out (KO) mouse model. The results demonstrated significant increases in bone mineral density and content in AAV2/8-GNPTAB-treated as compared to non-treated KO mice. We also showed that IL-6 (interleukin-6) expression in articular cartilage was reduced in AAV2/8-GNPTAB treated ML II mice. Together, these data suggest that AAV-mediated expression of GNPTAB in ML II mice can attenuate bone loss via inhibition of IL-6 production. This study emphasizes the value of the MLII KO mouse to recapitulate the clinical manifestations of the disease and highlights its amenability to therapy.
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Affiliation(s)
- Ah-Ra Ko
- Clinical Research Center, Samsung Biomedical Research Center, Seoul, Republic of Korea; Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Dong-Kyu Jin
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
| | - Sung Yoon Cho
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Sung Won Park
- Department of Pediatrics, Cheil General Hospital and Woman's Health Care Center, Dankook University College of Medicine, Seoul, Republic of Korea
| | | | | | | | - Jung-Sun Kim
- Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Min Jung Kwak
- Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea
| | - Su Jin Kim
- Department of Pediatrics, Myongji Hospital, Seonam University College of Medicine, Goyang, Republic of Korea
| | - Young Bae Sohn
- Department of Medical Genetics, Ajou University Hospital, Ajou University School of Medicine, Suwon, Republic of Korea
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102
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Potentiating the antitumour response of CD8(+) T cells by modulating cholesterol metabolism. Nature 2016; 531:651-5. [PMID: 26982734 DOI: 10.1038/nature17412] [Citation(s) in RCA: 624] [Impact Index Per Article: 78.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 02/10/2016] [Indexed: 12/16/2022]
Abstract
CD8(+) T cells have a central role in antitumour immunity, but their activity is suppressed in the tumour microenvironment. Reactivating the cytotoxicity of CD8(+) T cells is of great clinical interest in cancer immunotherapy. Here we report a new mechanism by which the antitumour response of mouse CD8(+) T cells can be potentiated by modulating cholesterol metabolism. Inhibiting cholesterol esterification in T cells by genetic ablation or pharmacological inhibition of ACAT1, a key cholesterol esterification enzyme, led to potentiated effector function and enhanced proliferation of CD8(+) but not CD4(+) T cells. This is due to the increase in the plasma membrane cholesterol level of CD8(+) T cells, which causes enhanced T-cell receptor clustering and signalling as well as more efficient formation of the immunological synapse. ACAT1-deficient CD8(+) T cells were better than wild-type CD8(+) T cells at controlling melanoma growth and metastasis in mice. We used the ACAT inhibitor avasimibe, which was previously tested in clinical trials for treating atherosclerosis and showed a good human safety profile, to treat melanoma in mice and observed a good antitumour effect. A combined therapy of avasimibe plus an anti-PD-1 antibody showed better efficacy than monotherapies in controlling tumour progression. ACAT1, an established target for atherosclerosis, is therefore also a potential target for cancer immunotherapy.
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103
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Quan X, Chen X, Sun D, Xu B, Zhao L, Shi X, Liu H, Gao B, Lu X. The mechanism of the effect of U18666a on blocking the activity of 3β-hydroxysterol Δ-24-reductase (DHCR24): molecular dynamics simulation study and free energy analysis. J Mol Model 2016; 22:46. [DOI: 10.1007/s00894-016-2907-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 01/07/2016] [Indexed: 11/28/2022]
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104
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Lu F, Liang Q, Abi-Mosleh L, Das A, De Brabander JK, Goldstein JL, Brown MS. Identification of NPC1 as the target of U18666A, an inhibitor of lysosomal cholesterol export and Ebola infection. eLife 2015; 4. [PMID: 26646182 PMCID: PMC4718804 DOI: 10.7554/elife.12177] [Citation(s) in RCA: 229] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/08/2015] [Indexed: 12/19/2022] Open
Abstract
Niemann-Pick C1 (NPC1) is a lysosomal membrane protein that exports cholesterol derived from receptor-mediated uptake of LDL, and it also mediates cellular entry of Ebola virus. Cholesterol export is inhibited by nanomolar concentrations of U18666A, a cationic sterol. To identify the target of U18666A, we synthesized U-X, a U18666A derivative with a benzophenone that permits ultraviolet-induced crosslinking. When added to CHO cells, U-X crosslinked to NPC1. Crosslinking was blocked by U18666A derivatives that block cholesterol export, but not derivatives lacking blocking activity. Crosslinking was prevented by point mutation in the sterol-sensing domain (SSD) of NPC1, but not by point mutation in the N-terminal domain (NTD). These data suggest that the SSD contains a U18666A-inhibitable site required for cholesterol export distinct from the cholesterol-binding site in the NTD. Inasmuch as inhibition of Ebola requires 100-fold higher concentrations of U18666A, the high affinity U16888A-binding site is likely not required for virus entry. DOI:http://dx.doi.org/10.7554/eLife.12177.001 Cholesterol is a type of fat molecule and is a vital component of animal cell membranes. It is taken up into cells within particles called low density lipoproteins (LDLs) that are then digested in cell compartments known as lysosomes to release the cholesterol. Then, the cholesterol leaves the lysosome with the help of a transport protein called NPC1. Mutations in the gene that encodes NPC1 lead to the accumulation of cholesterol in lysosomes; this can cause a devastating illness that affects the brain, liver and other organs. The NPC1 protein also plays a crucial role in allowing Ebola viruses to infect animal cells and multiply. U18666A is a drug that blocks the movement of cholesterol out of lysosomes and also inhibits Ebola virus infections, but it was not known what components it targets in cells. Lu et al. used a technique called ultraviolet-induced crosslinking to identify the proteins that U18666A can bind to. The experiments show that U18666A can directly bind to a site that is within a section of the NPC1 protein called the sterol-sensing domain. The binding of U18666A to this site blocks the movement of cholesterol out of lysosomes. Lu et al.’s findings indicate that the sterol-sensing domain of NPC1 plays a crucial role in cholesterol’s export from lysosomes. A future challenge is to use structural biology techniques (such as X-ray crystallography or cryo-electron microscope tomography) to understand the three-dimensional structure of NPC1. DOI:http://dx.doi.org/10.7554/eLife.12177.002
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Affiliation(s)
- Feiran Lu
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Qiren Liang
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, United States
| | - Lina Abi-Mosleh
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Akash Das
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Jef K De Brabander
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, United States
| | - Joseph L Goldstein
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
| | - Michael S Brown
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, United States
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105
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Copetti-Santos D, Moraes V, Weiler DF, de Mello AS, Machado FDS, Marinho JP, Siebert C, Kolling J, Funchal C, Wyse ATS, Coelho JC. U18666A Treatment Results in Cholesterol Accumulation, Reduced Na+, K+-ATPase Activity, and Increased Oxidative Stress in Rat Cortical Astrocytes. Lipids 2015; 50:937-44. [DOI: 10.1007/s11745-015-4062-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 08/14/2015] [Indexed: 12/27/2022]
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106
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Yao K, Wu J, Zhang J, Bo J, Hong Z, Zu H. Protective Effect of DHT on Apoptosis Induced by U18666A via PI3K/Akt Signaling Pathway in C6 Glial Cell Lines. Cell Mol Neurobiol 2015; 36:801-9. [PMID: 26340949 DOI: 10.1007/s10571-015-0263-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 08/27/2015] [Indexed: 11/27/2022]
Abstract
Various useful animal models, such as Alzheimer's disease and Niemann-Pick disease, were provided by U18666A. However, the pathogenesis of U18666A-induced diseases, including U18666A-mediated apoptosis, remains incompletely elucidated, and therapeutic strategies are still limited. Dihydrotestosterone (DHT) has been reported to contribute to the prevention and treatment of neurodegenerative disorders. Our study investigated the neuroprotective activity of DHT in U18666A-related diseases. Apoptosis of C6 cells was detected by Hoechst 33258 fluorescent staining and flow cytometry with annexin V-FITC/PI dual staining. Cell viability was assessed using Cell Counting Kit-8. Expression of apoptosis-related proteins, such as Akt, seladin-1, Bcl-2 family proteins, and caspase-3, was determined using Western blot. Our results demonstrated that the apoptotic rate of C6 cells significantly increased after U18666A addition, but was remarkably reduced after DHT treatment. Pretreatment with DHT attenuated U18666A-induced cell viability loss. PI3K inhibitor LY294002 could suppress DHT anti-apoptotic effect. Furthermore, we discovered that U18666A could significantly downregulate seladin-1 expression in a dose-dependent manner, but no significant change was observed in Bcl-xL, Bax, and P-Akt protein expressions. Compared with U18666A-treated group, the expression of P-Akt, seladin-1, and Bcl-xL significantly increased, and the expression of Bax and caspase-3 remarkably reduced after DHT treatment. However, in the presence of LY294002, the effect of DHT was reversed. In conclusion, we found that seladin-1 may take part in U18666A-induced apoptosis. DHT may inhibit U18666A-induced apoptosis by regulating downstream apoptosis-related proteins including seladin-1, caspase-3, Bcl-xL, and Bax through activation of the PI3K/Akt signal pathway.
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Affiliation(s)
- Kai Yao
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China
| | - Junfeng Wu
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China
| | - Jianfeng Zhang
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China
| | - Jimei Bo
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China
| | - Zhen Hong
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China
| | - Hengbing Zu
- Department of Neurology, Jinshan Hospital Affiliated to Fudan University, No. 1508 Longhang Road, Jinshan District, Shanghai, 201508, China.
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107
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Rhein BA, Maury WJ. Ebola virus entry into host cells: identifying therapeutic strategies. CURRENT CLINICAL MICROBIOLOGY REPORTS 2015; 2:115-124. [PMID: 26509109 PMCID: PMC4617201 DOI: 10.1007/s40588-015-0021-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Filoviruses cause severe hemorrhagic fever in humans. The archetypal virus of this group, Ebola virus, is responsible for the current filovirus epidemic in West Africa. Filoviruses infect most mammalian cells, resulting in broad species tropism and likely contributing to rapid spread of virus throughout the body. A thorough understanding of filovirus entry events will facilitate the development of therapeutics against these critical steps in the viral life cycle. This review summarizes the current understanding of filovirus entry and discusses some of the recent advancements in therapeutic strategies that target entry.
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Affiliation(s)
- Bethany A. Rhein
- Department of Microbiology, University of Iowa, 3-701 Bowen Science Building, 51 Newton Rd, Iowa City, IA 52242 USA
| | - Wendy J. Maury
- Department of Microbiology, University of Iowa, 3-701 Bowen Science Building, 51 Newton Rd, Iowa City, IA 52242 USA
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108
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Addressing Therapeutic Options for Ebola Virus Infection in Current and Future Outbreaks. Antimicrob Agents Chemother 2015; 59:5892-902. [PMID: 26248374 DOI: 10.1128/aac.01105-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Ebola virus can cause severe hemorrhagic disease with high fatality rates. Currently, no specific therapeutic agent or vaccine has been approved for treatment and prevention of Ebola virus infection of humans. Although the number of Ebola cases has fallen in the last few weeks, multiple outbreaks of Ebola virus infection and the likelihood of future exposure highlight the need for development and rapid evaluation of pre- and postexposure treatments. Here, we briefly review the existing and future options for anti-Ebola therapy, based on the data coming from rare clinical reports, studies on animals, and results from in vitro models. We also project the mechanistic hypotheses of several potential drugs against Ebola virus, including small-molecule-based drugs, which are under development and being tested in animal models or in vitro using various cell types. Our paper discusses strategies toward identifying and testing anti-Ebola virus properties of known and medically approved drugs, especially those that can limit the pathological inflammatory response in Ebola patients and thereby provide protection from mortality. We underline the importance of developing combinational therapy for better treatment outcomes for Ebola patients.
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109
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Abstract
Recent work demonstrated that the Niemann-Pick C1 (NPC1) protein is an essential entry receptor for filoviruses. While previous studies focused on filovirus entry requirements of NPC1 in vitro, its roles in filovirus replication and pathogenesis in vivo remain unclear. Here, we evaluated the importance of NPC1, and its partner in cholesterol transport, NPC2, by using a mouse model of Ebolavirus (EBOV) disease. We found that, whereas wild-type mice had high viral loads and succumbed to EBOV infection, Npc1−/− mice were entirely free of viral replication and completely protected from EBOV disease. Interestingly, Npc1+/− mice transiently developed high levels of viremia, but were nevertheless substantially protected from EBOV challenge. We also found Npc2−/− mice to be fully susceptible to EBOV infection, while Npc1−/− mice treated to deplete stored lysosomal cholesterol remained completely resistant to EBOV infection. These results provide mechanistic evidence that NPC1 is directly required for EBOV infection in vivo, with little or no role for NPC1/NPC2-dependent cholesterol transport. Finally, we assessed the in vivo antiviral efficacies of three compounds known to inhibit NPC1 function or NPC1-glycoprotein binding in vitro. Two compounds reduced viral titers in vivo and provided a modest, albeit not statistically significant, degree of protection. Taken together, our results show that NPC1 is critical for replication and pathogenesis in animals and is a bona fide target for development of antifilovirus therapeutics. Additionally, our findings with Npc1+/− mice raise the possibility that individuals heterozygous for NPC1 may have a survival advantage in the face of EBOV infection. Researchers have been searching for an essential filovirus receptor for decades, and numerous candidate receptors have been proposed. However, none of the proposed candidate receptors has proven essential in all in vitro scenarios, nor have they proven essential when evaluated using animal models. In this report, we provide the first example of a knockout mouse that is completely refractory to EBOV infection, replication, and disease. The findings detailed here provide the first critical in vivo data illustrating the absolute requirement of NPC1 for filovirus infection in mice. Our work establishes NPC1 as a legitimate target for the development of anti-EBOV therapeutics. However, the limited success of available NPC1 inhibitors to protect mice from EBOV challenge highlights the need for new molecules or approaches to target NPC1 in vivo.
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110
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Dahlmann F, Biedenkopf N, Babler A, Jahnen-Dechent W, Karsten CB, Gnirß K, Schneider H, Wrensch F, O'Callaghan CA, Bertram S, Herrler G, Becker S, Pöhlmann S, Hofmann-Winkler H. Analysis of Ebola Virus Entry Into Macrophages. J Infect Dis 2015; 212 Suppl 2:S247-57. [PMID: 25877552 PMCID: PMC4564540 DOI: 10.1093/infdis/jiv140] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Ebolaviruses constitute a public health threat, particularly in Central and Western Africa. Host cell factors required for spread of ebolaviruses may serve as targets for antiviral intervention. Lectins, TAM receptor tyrosine kinases (Tyro3, Axl, Mer), T cell immunoglobulin and mucin domain (TIM) proteins, integrins, and Niemann-Pick C1 (NPC1) have been reported to promote entry of ebolaviruses into certain cellular systems. However, the factors used by ebolaviruses to invade macrophages, major viral targets, are poorly defined. Here, we show that mannose-specific lectins, TIM-1 and Axl augment entry into certain cell lines but do not contribute to Ebola virus (EBOV)-glycoprotein (GP)-driven transduction of macrophages. In contrast, expression of Mer, integrin αV, and NPC1 was required for efficient GP-mediated transduction and EBOV infection of macrophages. These results define cellular factors hijacked by EBOV for entry into macrophages and, considering that Mer and integrin αV promote phagocytosis of apoptotic cells, support the concept that EBOV relies on apoptotic mimicry to invade target cells.
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Affiliation(s)
| | | | - Anne Babler
- Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University
| | | | - Christina B Karsten
- Infection Biology Unit, German Primate Center, Göttingen Institutes for Cellular Chemistry
| | - Kerstin Gnirß
- Infection Biology Unit, German Primate Center, Göttingen
| | | | | | | | | | - Georg Herrler
- Institute of Virology, University of Veterinary Medicine Hannover, Germany
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111
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Hofmann-Winkler H, Gnirß K, Wrensch F, Pöhlmann S. Comparative Analysis of Host Cell Entry of Ebola Virus From Sierra Leone, 2014, and Zaire, 1976. J Infect Dis 2015; 212 Suppl 2:S172-80. [PMID: 25840443 PMCID: PMC4564534 DOI: 10.1093/infdis/jiv101] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The ongoing Ebola virus (EBOV) disease (EVD) epidemic in Western Africa is the largest EVD outbreak recorded to date and requires the rapid development and deployment of antiviral measures. The viral glycoprotein (GP) facilitates host cell entry and, jointly with cellular interaction partners, constitutes a potential target for antiviral intervention. However, it is unknown whether the GPs of the currently and previously circulating EBOVs use the same mechanisms for cellular entry and are thus susceptible to inhibition by the same antivirals and cellular defenses. Here, we show that the GPs of the EBOVs circulating in 1976 and 2014 transduce the same spectrum of target cells, use the same cellular factors for host cell entry, and are comparably susceptible to blockade by antiviral interferon-induced transmembrane proteins and neutralizing antibody KZ52. Thus, the viruses responsible for the ongoing EVD epidemic should be fully susceptible to established antiviral strategies targeting GP and cellular entry factors.
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Affiliation(s)
| | - Kerstin Gnirß
- Infection Biology Unit, German Primate Center, Göttingen, Germany
| | - Florian Wrensch
- Infection Biology Unit, German Primate Center, Göttingen, Germany
| | - Stefan Pöhlmann
- Infection Biology Unit, German Primate Center, Göttingen, Germany
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112
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Albulescu L, Wubbolts R, van Kuppeveld FJM, Strating JRPM. Cholesterol shuttling is important for RNA replication of coxsackievirus B3 and encephalomyocarditis virus. Cell Microbiol 2015; 17:1144-56. [PMID: 25645595 DOI: 10.1111/cmi.12425] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 01/21/2015] [Accepted: 01/26/2015] [Indexed: 11/29/2022]
Abstract
Picornaviruses are a family of positive-strand RNA viruses that includes important human and animal pathogens. Upon infection, picornaviruses induce an extensive remodelling of host cell membranes into replication organelles (ROs), which is critical for replication. Membrane lipids and lipid remodelling processes are at the base of RO formation, yet their involvement remains largely obscure. Recently, phosphatidylinositol-4-phosphate was the first lipid discovered to be important for the replication of a number of picornaviruses. Here, we investigate the role of the lipid cholesterol in picornavirus replication. We show that two picornaviruses from distinct genera that rely on different host factors for replication, namely the enterovirus coxsackievirus B3 (CVB3) and the cardiovirus encephalomyocarditis virus (EMCV), both recruited cholesterol to their ROs. Although CVB3 and EMCV both required cholesterol for efficient genome replication, the viruses appeared to rely on different cellular cholesterol pools. Treatments that altered the distribution of endosomal cholesterol inhibited replication of both CVB3 and EMCV, showing the importance of endosomal cholesterol shuttling for the replication of these viruses. Summarizing, we here demonstrate the importance of cholesterol homeostasis for efficient replication of CVB3 and EMCV.
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Affiliation(s)
- Lucian Albulescu
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Richard Wubbolts
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Frank J M van Kuppeveld
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Jeroen R P M Strating
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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113
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Yim YI, Park BC, Yadavalli R, Zhao X, Eisenberg E, Greene LE. The multivesicular body is the major internal site of prion conversion. J Cell Sci 2015; 128:1434-43. [PMID: 25663703 PMCID: PMC4379730 DOI: 10.1242/jcs.165472] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The conversion of the properly folded prion protein, PrPc, to its misfolded amyloid form, PrPsc, occurs as the two proteins traffic along the endocytic pathway and PrPc is exposed to PrPsc. To determine the specific site of prion conversion, we knocked down various proteins in the endocytic pathway including Rab7a, Tsg101 and Hrs (also known as HGS). PrPsc was markedly reduced in two chronically infected cell lines by preventing the maturation of the multivesicular body, a process that begins in the early endosome and ends with the sorting of cargo to the lysosome. By contrast, knocking down proteins in the retromer complex, which diverts cargo away from the multivesicular body caused an increase in PrPsc levels. These results suggest that the multivesicular body is the major site for intracellular conversion of PrPc to PrPsc.
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Affiliation(s)
- Yang-In Yim
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Bum-Chan Park
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| | | | - Xiaohong Zhao
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Evan Eisenberg
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Lois E Greene
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
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114
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Small molecule inhibitors of ebola virus infection. Drug Discov Today 2015; 20:277-86. [DOI: 10.1016/j.drudis.2014.12.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 12/01/2014] [Accepted: 12/12/2014] [Indexed: 12/13/2022]
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115
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Marquer C, Laine J, Dauphinot L, Hanbouch L, Lemercier-Neuillet C, Pierrot N, Bossers K, Le M, Corlier F, Benstaali C, Saudou F, Thinakaran G, Cartier N, Octave JN, Duyckaerts C, Potier MC. Increasing membrane cholesterol of neurons in culture recapitulates Alzheimer's disease early phenotypes. Mol Neurodegener 2014; 9:60. [PMID: 25524049 PMCID: PMC4280040 DOI: 10.1186/1750-1326-9-60] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 12/03/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND It is suspected that excess of brain cholesterol plays a role in Alzheimer's disease (AD). Membrane-associated cholesterol was shown to be increased in the brain of individuals with sporadic AD and to correlate with the severity of the disease. We hypothesized that an increase of membrane cholesterol could trigger sporadic AD early phenotypes. RESULTS We thus acutely loaded the plasma membrane of cultured neurons with cholesterol to reach the 30% increase observed in AD brains. We found changes in gene expression profiles that are reminiscent of early AD stages. We also observed early AD cellular phenotypes. Indeed we found enlarged and aggregated early endosomes using confocal and electron microscopy after immunocytochemistry. In addition amyloid precursor protein vesicular transport was inhibited in neuronal processes, as seen by live-imaging. Finally transient membrane cholesterol loading lead to significantly increased amyloid-β42 secretion. CONCLUSIONS Membrane cholesterol increase in cultured neurons reproduces most early AD changes and could thus be a relevant model for deciphering AD mechanisms and identifying new therapeutic targets.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Marie-Claude Potier
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, UM 75, U 1127, UMR 7225, ICM, 75013 Paris, France.
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116
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Cellular Localization and Trafficking of the Human ABCG1 Transporter. BIOLOGY 2014; 3:781-800. [PMID: 25405320 PMCID: PMC4280511 DOI: 10.3390/biology3040781] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 10/23/2014] [Accepted: 10/28/2014] [Indexed: 11/17/2022]
Abstract
We have developed a suitable heterologous cell expression system to study the localization, trafficking, and site(s) of function of the human ABCG1 transporter. Increased plasma membrane (PM) and late endosomal (LE) cholesterol generated by ABCG1 was removed by lipoproteins and liposomes, but not apoA-I. Delivery of ABCG1 to the PM and LE was required for ABCG1-mediated cellular cholesterol efflux. ABCG1 LEs frequently contacted the PM, providing a collisional mechanism for transfer of ABCG1-mobilized cholesterol, similar to ABCG1-mediated PM cholesterol efflux to lipoproteins. ABCG1-mobilized LE cholesterol also trafficked to the PM by a non-vesicular pathway. Transfer of ABCG1-mobilized cholesterol from the cytoplasmic face of LEs to the PM and concomitant removal of cholesterol from the outer leaflet of the PM bilayer by extracellular acceptors suggests that ABCG1 mobilizes cholesterol on both sides of the lipid bilayer for removal by acceptors. ABCG1 increased uptake of HDL into LEs, consistent with a potential ABCG1-mediated cholesterol efflux pathway involving HDL resecretion. Thus, ABCG1 at the PM mobilizes PM cholesterol and ABCG1 in LE/LYS generates mobile pools of cholesterol that can traffic by both vesicular and non-vesicular pathways to the PM where it can also be transferred to extracellular acceptors with a lipid surface.
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Fucho R, Martínez L, Baulies A, Torres S, Tarrats N, Fernandez A, Ribas V, Astudillo AM, Balsinde J, Garcia-Rovés P, Elena M, Bergheim I, Lotersztajn S, Trautwein C, Appelqvist H, Paton AW, Paton JC, Czaja MJ, Kaplowitz N, Fernandez-Checa JC, García-Ruiz C. ASMase regulates autophagy and lysosomal membrane permeabilization and its inhibition prevents early stage non-alcoholic steatohepatitis. J Hepatol 2014; 61:1126-34. [PMID: 24946279 PMCID: PMC4203709 DOI: 10.1016/j.jhep.2014.06.009] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 05/12/2014] [Accepted: 06/05/2014] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS Acid sphingomyelinase (ASMase) is activated in non-alcoholic steatohepatitis (NASH). However, the contribution of ASMase to NASH is poorly understood and limited to hepatic steatosis and glucose metabolism. Here we examined the role of ASMase in high fat diet (HFD)-induced NASH. METHODS Autophagy, endoplasmic reticulum (ER) stress and lysosomal membrane permeabilization (LMP) were determined in ASMase(-/-) mice fed a HFD. The impact of pharmacological ASMase inhibition on NASH was analyzed in wild type mice fed a HFD. RESULTS ASMase deficiency determined resistance to hepatic steatosis mediated by a HFD or methionine-choline deficient diet. ASMase(-/-) mice were resistant to HFD-induced hepatic ER stress, but sensitive to tunicamycin-mediated ER stress, indicating selectivity in the resistance of ASMase(-/-) mice to ER stress and steatosis. Autophagic flux, determined in the presence of rapamycin and/or chloroquine, was lower in primary mouse hepatocytes (PMH) from ASMase(-/-) mice and accompanied by increased p62 levels, suggesting autophagic impairment. Moreover, autophagy suppression by chloroquine and brefeldin A caused ER stress in PMH from ASMase(+/+) mice but not in ASMase(-/-) mice. ASMase(-/-) PMH exhibited increased lysosomal cholesterol loading, decreased LMP and apoptosis resistance induced by O-methyl-serine dodecylamide hydrochloride or palmitic acid, effects that were reversed by decreasing cholesterol levels by oxysterol 25-hydroxycholesterol. In vivo pharmacological ASMase inhibition by amitriptyline, a widely used tricyclic antidepressant, protected wild type mice against HFD-induced hepatic steatosis, fibrosis, and liver damage, effects indicative of early-stage NASH. CONCLUSIONS These findings underscore a critical role for ASMase in diet-induced NASH and suggest the potential of amitriptyline as a treatment for patients with NASH.
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Affiliation(s)
- Raquel Fucho
- Department of Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain; Liver Unit, IDIBAPS Hospital Clinic de Barcelona and CIBEREHD, Barcelona, Spain
| | - Laura Martínez
- Department of Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain; Liver Unit, IDIBAPS Hospital Clinic de Barcelona and CIBEREHD, Barcelona, Spain
| | - Anna Baulies
- Department of Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain; Liver Unit, IDIBAPS Hospital Clinic de Barcelona and CIBEREHD, Barcelona, Spain
| | - Sandra Torres
- Department of Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain; Liver Unit, IDIBAPS Hospital Clinic de Barcelona and CIBEREHD, Barcelona, Spain
| | - Nuria Tarrats
- Department of Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain; Liver Unit, IDIBAPS Hospital Clinic de Barcelona and CIBEREHD, Barcelona, Spain
| | - Anna Fernandez
- Department of Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain; Liver Unit, IDIBAPS Hospital Clinic de Barcelona and CIBEREHD, Barcelona, Spain
| | - Vicente Ribas
- Department of Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain; Liver Unit, IDIBAPS Hospital Clinic de Barcelona and CIBEREHD, Barcelona, Spain
| | - Alma M Astudillo
- Institute of Molecular Biology and Genetics CSIC, Medical School, University of Valladolid and CIBERDEM, Valladolid, Spain
| | - Jesús Balsinde
- Institute of Molecular Biology and Genetics CSIC, Medical School, University of Valladolid and CIBERDEM, Valladolid, Spain
| | - Pablo Garcia-Rovés
- Diabetes and Obesity Laboratory, IDIBAPS-Hospital Clinic de Barcelona, Barcelona, Spain
| | - Montserrat Elena
- Biochemical Service, Hospital Clinic de Barcelona, Barcelona, Spain
| | - Ina Bergheim
- Department of Nutritional Sciences, Friedrich-Schiller-University, Jena, Germany
| | | | - Christian Trautwein
- Department of Internal Medicine III, University Hospital, RWTH Aachen, Aachen, Germany
| | - Hanna Appelqvist
- Experimental Pathology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden
| | - Adrienne W Paton
- Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Australia
| | - Mark J Czaja
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Neil Kaplowitz
- Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Jose C Fernandez-Checa
- Department of Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain; Liver Unit, IDIBAPS Hospital Clinic de Barcelona and CIBEREHD, Barcelona, Spain; Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.
| | - Carmen García-Ruiz
- Department of Cell Death and Proliferation, IIBB-CSIC, Barcelona, Spain; Liver Unit, IDIBAPS Hospital Clinic de Barcelona and CIBEREHD, Barcelona, Spain; Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.
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118
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Wrensch F, Winkler M, Pöhlmann S. IFITM proteins inhibit entry driven by the MERS-coronavirus spike protein: evidence for cholesterol-independent mechanisms. Viruses 2014; 6:3683-98. [PMID: 25256397 PMCID: PMC4189045 DOI: 10.3390/v6093683] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 09/23/2014] [Accepted: 09/23/2014] [Indexed: 01/11/2023] Open
Abstract
The interferon-inducible transmembrane (IFITM) proteins 1, 2 and 3 inhibit the host cell entry of several enveloped viruses, potentially by promoting the accumulation of cholesterol in endosomal compartments. IFITM3 is essential for control of influenza virus infection in mice and humans. In contrast, the role of IFITM proteins in coronavirus infection is less well defined. Employing a retroviral vector system for analysis of coronavirus entry, we investigated the susceptibility of human-adapted and emerging coronaviruses to inhibition by IFITM proteins. We found that entry of the recently emerged Middle East respiratory syndrome coronavirus (MERS-CoV) is sensitive to inhibition by IFITM proteins. In 293T cells, IFITM-mediated inhibition of cellular entry of the emerging MERS- and SARS-CoV was less efficient than blockade of entry of the globally circulating human coronaviruses 229E and NL63. Similar differences were not observed in A549 cells, suggesting that cellular context and/or IFITM expression levels can impact inhibition efficiency. The differential IFITM-sensitivity of coronaviruses observed in 293T cells afforded the opportunity to investigate whether efficiency of entry inhibition by IFITMs and endosomal cholesterol accumulation correlate. No such correlation was observed. Furthermore, entry mediated by the influenza virus hemagglutinin was robustly inhibited by IFITM3 but was insensitive to accumulation of endosomal cholesterol, indicating that modulation of cholesterol synthesis/transport did not account for the antiviral activity of IFITM3. Collectively, these results show that the emerging MERS-CoV is a target of the antiviral activity of IFITM proteins and demonstrate that mechanisms other than accumulation of endosomal cholesterol can contribute to viral entry inhibition by IFITMs.
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Affiliation(s)
- Florian Wrensch
- Infection Biology Unit, German Primate Center, 37077 Göttingen, Germany.
| | - Michael Winkler
- Infection Biology Unit, German Primate Center, 37077 Göttingen, Germany.
| | - Stefan Pöhlmann
- Infection Biology Unit, German Primate Center, 37077 Göttingen, Germany.
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119
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Park EJ, Grabińska KA, Guan Z, Stránecký V, Hartmannová H, Hodaňová K, Barešová V, Sovová J, Jozsef L, Ondrušková N, Hansíková H, Honzík T, Zeman J, Hůlková H, Wen R, Kmoch S, Sessa WC. Mutation of Nogo-B receptor, a subunit of cis-prenyltransferase, causes a congenital disorder of glycosylation. Cell Metab 2014; 20:448-57. [PMID: 25066056 PMCID: PMC4161961 DOI: 10.1016/j.cmet.2014.06.016] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 05/28/2014] [Accepted: 06/14/2014] [Indexed: 11/20/2022]
Abstract
Dolichol is an obligate carrier of glycans for N-linked protein glycosylation, O-mannosylation, and GPI anchor biosynthesis. cis-prenyltransferase (cis-PTase) is the first enzyme committed to the synthesis of dolichol. However, the proteins responsible for mammalian cis-PTase activity have not been delineated. Here we show that Nogo-B receptor (NgBR) is a subunit required for dolichol synthesis in yeast, mice, and man. Moreover, we describe a family with a congenital disorder of glycosylation caused by a loss of function mutation in the conserved C terminus of NgBR-R290H and show that fibroblasts isolated from patients exhibit reduced dolichol profiles and enhanced accumulation of free cholesterol identically to fibroblasts from mice lacking NgBR. Mutation of NgBR-R290H in man and orthologs in yeast proves the importance of this evolutionarily conserved residue for mammalian cis-PTase activity and function. Thus, these data provide a genetic basis for the essential role of NgBR in dolichol synthesis and protein glycosylation.
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Affiliation(s)
- Eon Joo Park
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06520, USA
| | - Kariona A Grabińska
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06520, USA
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, DUMC 2927, Durham, NC 27710, USA
| | - Viktor Stránecký
- Institute for Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, Prague 2, 128 08 Czech Republic
| | - Hana Hartmannová
- Institute for Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, Prague 2, 128 08 Czech Republic
| | - Kateřina Hodaňová
- Institute for Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, Prague 2, 128 08 Czech Republic
| | - Veronika Barešová
- Institute for Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, Prague 2, 128 08 Czech Republic
| | - Jana Sovová
- Institute for Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, Prague 2, 128 08 Czech Republic
| | - Levente Jozsef
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06520, USA
| | - Nina Ondrušková
- Department of Pediatrics, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, Prague 2, 128 08 Czech Republic
| | - Hana Hansíková
- Department of Pediatrics, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, Prague 2, 128 08 Czech Republic
| | - Tomáš Honzík
- Department of Pediatrics, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, Prague 2, 128 08 Czech Republic
| | - Jiří Zeman
- Department of Pediatrics, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, Prague 2, 128 08 Czech Republic
| | - Helena Hůlková
- Institute for Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, Prague 2, 128 08 Czech Republic
| | - Rong Wen
- Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, 900 NW 17th Street, Miami, FL 33136, USA
| | - Stanislav Kmoch
- Institute for Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Ke Karlovu 2, Prague 2, 128 08 Czech Republic.
| | - William C Sessa
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06520, USA.
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Eckert N, Wrensch F, Gärtner S, Palanisamy N, Goedecke U, Jäger N, Pöhlmann S, Winkler M. Influenza A virus encoding secreted Gaussia luciferase as useful tool to analyze viral replication and its inhibition by antiviral compounds and cellular proteins. PLoS One 2014; 9:e97695. [PMID: 24842154 PMCID: PMC4026478 DOI: 10.1371/journal.pone.0097695] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Accepted: 04/23/2014] [Indexed: 01/22/2023] Open
Abstract
Reporter genes inserted into viral genomes enable the easy and rapid quantification of virus replication, which is instrumental to efficient in vitro screening of antiviral compounds or in vivo analysis of viral spread and pathogenesis. Based on a published design, we have generated several replication competent influenza A viruses carrying either fluorescent proteins or Gaussia luciferase. Reporter activity could be readily quantified in infected cultures, but the virus encoding Gaussia luciferase was more stable than viruses bearing fluorescent proteins and was therefore analyzed in detail. Quantification of Gaussia luciferase activity in the supernatants of infected culture allowed the convenient and highly sensitive detection of viral spread, and enzymatic activity correlated with the number of infectious particles released from infected cells. Furthermore, the Gaussia luciferase encoding virus allowed the sensitive quantification of the antiviral activity of the neuraminidase inhibitor (NAI) zanamivir and the host cell interferon-inducible transmembrane (IFITM) proteins 1–3, which are known to inhibit influenza virus entry. Finally, the virus was used to demonstrate that influenza A virus infection is sensitive to a modulator of endosomal cholesterol, in keeping with the concept that IFITMs inhibit viral entry by altering cholesterol levels in the endosomal membrane. In sum, we report the characterization of a novel influenza A reporter virus, which allows fast and sensitive detection of viral spread and its inhibition, and we show that influenza A virus entry is sensitive to alterations of endosomal cholesterol levels.
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Affiliation(s)
- Nadine Eckert
- Infection Biology Unit, German Primate Center, Göttingen, Germany
| | - Florian Wrensch
- Infection Biology Unit, German Primate Center, Göttingen, Germany
| | - Sabine Gärtner
- Infection Biology Unit, German Primate Center, Göttingen, Germany
| | | | - Ulrike Goedecke
- Infection Biology Unit, German Primate Center, Göttingen, Germany
| | - Nils Jäger
- Infection Biology Unit, German Primate Center, Göttingen, Germany
| | - Stefan Pöhlmann
- Infection Biology Unit, German Primate Center, Göttingen, Germany
| | - Michael Winkler
- Infection Biology Unit, German Primate Center, Göttingen, Germany
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121
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Fletcher R, Gribben C, Ma X, Burchfield JG, Thomas KC, Krycer JR, James DE, Fazakerley DJ. The role of the Niemann-Pick disease, type C1 protein in adipocyte insulin action. PLoS One 2014; 9:e95598. [PMID: 24752197 PMCID: PMC3994084 DOI: 10.1371/journal.pone.0095598] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 03/28/2014] [Indexed: 12/12/2022] Open
Abstract
The Niemann-Pick disease, type C1 (NPC1) gene encodes a transmembrane protein involved in cholesterol efflux from the lysosome. SNPs within NPC1 have been associated with obesity and type 2 diabetes, and mice heterozygous or null for NPC1 are insulin resistant. However, the molecular mechanism underpinning this association is currently undefined. This study aimed to investigate the effects of inhibiting NPC1 function on insulin action in adipocytes. Both pharmacological and genetic inhibition of NPC1 impaired insulin action. This impairment was evident at the level of insulin signalling and insulin-mediated glucose transport in the short term and decreased GLUT4 expression due to reduced liver X receptor (LXR) transcriptional activity in the long-term. These data show that cholesterol homeostasis through NPC1 plays a crucial role in maintaining insulin action at multiple levels in adipocytes.
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Affiliation(s)
- Rachael Fletcher
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Christopher Gribben
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Xuiquan Ma
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - James G. Burchfield
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Kristen C. Thomas
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - James R. Krycer
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, Australia
| | - David E. James
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- Charles Perkins Centre, School of Molecular Bioscience, The University of Sydney, Sydney, Australia
| | - Daniel J. Fazakerley
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- * E-mail:
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Abstract
UNLABELLED Several arenaviruses are known to cause viral hemorrhagic fever (VHF) in sub-Saharan Africa and South America, where VHF is a major public health and medical concern. The biosafety level 4 categorization of these arenaviruses restricts their use and has impeded biological studies, including therapeutic drug and/or vaccine development. Due to difficulties associated with handling live viruses, pseudotype viruses, which transiently bear arenavirus envelope proteins based on vesicular stomatitis virus (VSV) or retrovirus, have been developed as surrogate virus systems. Here, we report the development of a pseudotype VSV bearing each envelope protein of various species of arenaviruses (AREpv), including the newly identified Lujo virus (LUJV) and Chapare virus. Pseudotype arenaviruses generated in 293T cells exhibited high infectivity in various mammalian cell lines. The infections by New World and Old World AREpv were dependent on their receptors (human transferrin receptor 1 [hTfR1] and α-dystroglycan [αDG], respectively). However, infection by pseudotype VSV bearing the LUJV envelope protein (LUJpv) occurred independently of hTfR1 and αDG, indicating that LUJpv utilizes an unidentified receptor. The pH-dependent endocytosis of AREpv was confirmed by the use of lysosomotropic agents. The fusion of cells expressing these envelope proteins, except for those expressing the LUJV envelope protein, was induced by transient treatment at low pH values. LUJpv infectivity was inhibited by U18666A, a cholesterol transport inhibitor. Furthermore, the infectivity of LUJpv was significantly decreased in the Niemann-Pick C1 (NPC1)-deficient cell line, suggesting the necessity for NPC1 activity for efficient LUJpv infection. IMPORTANCE LUJV is a newly identified arenavirus associated with a VHF outbreak in southern Africa. Although cell entry for many arenaviruses has been studied, cell entry for LUJV has not been characterized. In this study, we found that LUJpv utilizes neither αDG nor hTfR1 as a receptor and found unique characteristics of LUJV glycoprotein in membrane fusion and cell entry. Proper exclusion of cholesterol or some kinds of lipids may play important roles in LUJpv cell entry.
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123
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Vance JE, Karten B. Niemann-Pick C disease and mobilization of lysosomal cholesterol by cyclodextrin. J Lipid Res 2014; 55:1609-21. [PMID: 24664998 DOI: 10.1194/jlr.r047837] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Indexed: 12/31/2022] Open
Abstract
Niemann-Pick type C (NPC) disease is a lysosomal storage disease in which endocytosed cholesterol becomes sequestered in late endosomes/lysosomes (LEs/Ls) because of mutations in either the NPC1 or NPC2 gene. Mutations in either of these genes can lead to impaired functions of the NPC1 or NPC2 proteins and progressive neurodegeneration as well as liver and lung disease. NPC1 is a polytopic protein of the LE/L limiting membrane, whereas NPC2 is a soluble protein in the LE/L lumen. These two proteins act in tandem and promote the export of cholesterol from LEs/Ls. Consequently, a defect in either NPC1 or NPC2 causes cholesterol accumulation in LEs/Ls. In this review, we summarize the molecular mechanisms leading to NPC disease, particularly in the CNS. Recent exciting data on the mechanism by which the cholesterol-sequestering agent cyclodextrin can bypass the functions of NPC1 and NPC2 in the LEs/Ls, and mobilize cholesterol from LEs/Ls, will be highlighted. Moreover, the possible use of cyclodextrin as a valuable therapeutic agent for treatment of NPC patients will be considered.
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Affiliation(s)
- Jean E Vance
- The Group on Molecular and Cell Biology of Lipids and Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Barbara Karten
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
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124
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Ali-Rahmani F, Huang MA, Schengrund CL, Connor JR, Lee SY. C282Y-HFE gene variant affects cholesterol metabolism in human neuroblastoma cells. PLoS One 2014; 9:e88724. [PMID: 24533143 PMCID: PMC3922969 DOI: 10.1371/journal.pone.0088724] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 01/10/2014] [Indexed: 11/26/2022] Open
Abstract
Although disruptions in the maintenance of iron and cholesterol metabolism have been implicated in several cancers, the association between variants in the HFE gene that is associated with cellular iron uptake and cholesterol metabolism has not been studied. The C282Y-HFE variant is a risk factor for different cancers, is known to affect sphingolipid metabolism, and to result in increased cellular iron uptake. The effect of this variant on cholesterol metabolism and its possible relevance to cancer phenotype was investigated using wild type (WT) and C282Y-HFE transfected human neuroblastoma SH-SY5Y cells. Expression of C282Y-HFE in SH-SY5Y cells resulted in a significant increase in total cholesterol as well as increased transcription of a number of genes involved in its metabolism compared to cells expressing WT-HFE. The marked increase in expression of NPC1L1 relative to that of most other genes, was accompanied by a significant increase in expression of NPC1, a protein that functions in cholesterol uptake by cells. Because inhibitors of cholesterol metabolism have been proposed to be beneficial for treating certain cancers, their effect on the viability of C282Y-HFE neuroblastoma cells was ascertained. C282Y-HFE cells were significantly more sensitive than WT-HFE cells to U18666A, an inhibitor of desmosterol Δ24-reductase the enzyme catalyzing the last step in cholesterol biosynthesis. This was not seen for simvastatin, ezetimibe, or a sphingosine kinase inhibitor. These studies indicate that cancers presenting in carriers of the C282Y-HFE allele might be responsive to treatment designed to selectively reduce cholesterol content in their tumor cells.
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Affiliation(s)
- Fatima Ali-Rahmani
- Department of Neurosurgery, The Pennsylvania State University College of Medicine, Penn State Hershey Cancer Institute, Penn State M.S. Hershey Medical Center, Hershey, Pennsylvania, United States of America
| | - Michael A Huang
- Division of Pediatric Hematology/Oncology, The Pennsylvania State University College of Medicine, Penn State Hershey Cancer Institute, Penn State M.S. Hershey Medical Center, Hershey, Pennsylvania, United States of America
| | - C-L Schengrund
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Penn State Hershey Cancer Institute, Penn State M.S. Hershey Medical Center, Hershey, Pennsylvania, United States of America
| | - James R Connor
- Department of Neurosurgery, The Pennsylvania State University College of Medicine, Penn State Hershey Cancer Institute, Penn State M.S. Hershey Medical Center, Hershey, Pennsylvania, United States of America
| | - Sang Y Lee
- Department of Neurosurgery, The Pennsylvania State University College of Medicine, Penn State Hershey Cancer Institute, Penn State M.S. Hershey Medical Center, Hershey, Pennsylvania, United States of America
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Canfrán-Duque A, Pastor Ó, Quintana-Portillo R, Lerma M, de la Peña G, Martín-Hidalgo A, Fernández-Hernando C, Lasunción MA, Busto R. Curcumin promotes exosomes/microvesicles secretion that attenuates lysosomal cholesterol traffic impairment. Mol Nutr Food Res 2013; 58:687-97. [DOI: 10.1002/mnfr.201300350] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 09/10/2013] [Accepted: 09/20/2013] [Indexed: 01/24/2023]
Affiliation(s)
- Alberto Canfrán-Duque
- Servicio de Bioquímica-Investigación; Hospital Universitario Ramón y Cajal; Instituto Ramón y Cajal de Investigación Sanitaria (IRyCIS); Madrid Spain
| | - Óscar Pastor
- Servicio de Bioquímica-Clínica; Hospital Universitario Ramón y Cajal; IRyCIS; Madrid Spain
| | - Rocío Quintana-Portillo
- Servicio de Bioquímica-Investigación; Hospital Universitario Ramón y Cajal; Instituto Ramón y Cajal de Investigación Sanitaria (IRyCIS); Madrid Spain
| | - Milagros Lerma
- Servicio de Bioquímica-Clínica; Hospital Universitario Ramón y Cajal; IRyCIS; Madrid Spain
| | - Gema de la Peña
- Servicio de Bioquímica-Investigación; Hospital Universitario Ramón y Cajal; Instituto Ramón y Cajal de Investigación Sanitaria (IRyCIS); Madrid Spain
| | - Antonia Martín-Hidalgo
- Servicio de Bioquímica-Investigación; Hospital Universitario Ramón y Cajal; Instituto Ramón y Cajal de Investigación Sanitaria (IRyCIS); Madrid Spain
- CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn); ISCIII; Spain
| | - Carlos Fernández-Hernando
- Marc and Ruti Bell Vascular Biology and Disease Program; Leon H. Charney Division of Cardiology; Departments of Medicine and Cell Biology; New York University School of Medicine; New York NY USA
| | - Miguel A. Lasunción
- Servicio de Bioquímica-Investigación; Hospital Universitario Ramón y Cajal; Instituto Ramón y Cajal de Investigación Sanitaria (IRyCIS); Madrid Spain
- CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn); ISCIII; Spain
| | - Rebeca Busto
- Servicio de Bioquímica-Investigación; Hospital Universitario Ramón y Cajal; Instituto Ramón y Cajal de Investigación Sanitaria (IRyCIS); Madrid Spain
- CIBER de Fisiopatología de la Obesidad y Nutrición (CIBERobn); ISCIII; Spain
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Kollmann K, Pestka JM, Kühn SC, Schöne E, Schweizer M, Karkmann K, Otomo T, Catala-Lehnen P, Failla AV, Marshall RP, Krause M, Santer R, Amling M, Braulke T, Schinke T. Decreased bone formation and increased osteoclastogenesis cause bone loss in mucolipidosis II. EMBO Mol Med 2013; 5:1871-86. [PMID: 24127423 PMCID: PMC3914524 DOI: 10.1002/emmm.201302979] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 09/06/2013] [Accepted: 09/09/2013] [Indexed: 01/03/2023] Open
Abstract
Mucolipidosis type II (MLII) is a severe multi-systemic genetic disorder caused by missorting of lysosomal proteins and the subsequent lysosomal storage of undegraded macromolecules. Although affected children develop disabling skeletal abnormalities, their pathogenesis is not understood. Here we report that MLII knock-in mice, recapitulating the human storage disease, are runted with accompanying growth plate widening, low trabecular bone mass and cortical porosity. Intralysosomal deficiency of numerous acid hydrolases results in accumulation of storage material in chondrocytes and osteoblasts, and impaired bone formation. In osteoclasts, no morphological or functional abnormalities are detected whereas osteoclastogenesis is dramatically increased in MLII mice. The high number of osteoclasts in MLII is associated with enhanced osteoblastic expression of the pro-osteoclastogenic cytokine interleukin-6, and pharmacological inhibition of bone resorption prevented the osteoporotic phenotype of MLII mice. Our findings show that progressive bone loss in MLII is due to the presence of dysfunctional osteoblasts combined with excessive osteoclastogenesis. They further underscore the importance of a deep skeletal phenotyping approach for other lysosomal diseases in which bone loss is a prominent feature.
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Affiliation(s)
- Katrin Kollmann
- Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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127
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Ríos-Marco P, Martín-Fernández M, Soria-Bretones I, Ríos A, Carrasco MP, Marco C. Alkylphospholipids deregulate cholesterol metabolism and induce cell-cycle arrest and autophagy in U-87 MG glioblastoma cells. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1831:1322-34. [PMID: 23707264 DOI: 10.1016/j.bbalip.2013.05.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 05/08/2013] [Accepted: 05/13/2013] [Indexed: 11/27/2022]
Abstract
Glioblastoma is the most common malignant primary brain tumour in adults and one of the most lethal of all cancers. Growing evidence suggests that human tumours undergo abnormal lipid metabolism, characterised by an alteration in the mechanisms that regulate cholesterol homeostasis. We have investigated the effect that different antitumoural alkylphospholipids (APLs) exert upon cholesterol metabolism in the U-87 MG glioblastoma cell line. APLs altered cholesterol homeostasis by interfering with its transport from the plasma membrane to the endoplasmic reticulum (ER), thus hindering its esterification. At the same time they stimulated the synthesis of cholesterol from radiolabelled acetate and its internalisation from low-density lipoproteins (LDLs), inducing both 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and LDL receptor (LDLR) genes. Fluorescent microscopy revealed that these effects promoted the accumulation of intracellular cholesterol. Filipin staining demonstrated that this accumulation was not confined to the late endosome/lysosome (LE/LY) compartment since it did not colocalise with LAMP2 lysosomal marker. Furthermore, APLs inhibited cell growth, producing arrest at the G2/M phase. We also used transmission electron microscopy (TEM) to investigate ultrastructural alterations induced by APLs and found an abundant presence of autophagic vesicles and autolysosomes in treated cells, indicating the induction of autophagy. Thus our findings clearly demonstrate that antitumoural APLs interfere with the proliferation of the glioblastoma cell line via a complex mechanism involving cholesterol metabolism, cell-cycle arrest or autophagy. Knowledge of the interrelationship between these processes is fundamental to our understanding of tumoural response and may facilitate the development of novel therapeutics to improve treatment of glioblastoma and other types of cancer.
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Affiliation(s)
- Pablo Ríos-Marco
- Department of Biochemistry and Molecular Biology I, University of Granada, Granada, Spain
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128
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Abstract
A common feature of neurodegenerative diseases is the accumulation of disease-specific, aggregated protein species in the nervous system. Transmissible spongiform encephalopathies are universally fatal neurodegenerative diseases involving the transconformation and aggregation of prion proteins. At the cellular level macroautophagy has been identified as an efficient pathway for the clearance of these toxic protein aggregates. Hence, recent research has focused on the pharmacological manipulation of autophagy as a potential treatment for neurodegenerative diseases. Independent of their effects on the estrogen receptor, tamoxifen and its metabolite 4-hydroxytamoxifen are well known inducers of autophagy. However, we recently reported that the ability of 4-hydroxytamoxifen to clear prion infection is independent of autophagy. In contrast, we provide a model whereby perturbation of cholesterol metabolism, and not autophagy, is the main mechanism whereby 4-hydroxytamoxifen is able to exert its anti-prion effects. Thus, while tamoxifen, a widely available pharmaceutical, may have applications in prion therapy, prions may also represent a special case and may require different pharmacological interventions than other proteinopathies.
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Affiliation(s)
- Duncan Browman
- Institut Pasteur; Unite ́ de traffic membranaire et pathogenèse; Paris, France
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129
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Jones RJ, Gu D, Bjorklund CC, Kuiatse I, Remaley AT, Bashir T, Vreys V, Orlowski RZ. The novel anticancer agent JNJ-26854165 induces cell death through inhibition of cholesterol transport and degradation of ABCA1. J Pharmacol Exp Ther 2013; 346:381-92. [PMID: 23820125 DOI: 10.1124/jpet.113.204958] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
JNJ-26854165 (serdemetan) has previously been reported to inhibit the function of the E3 ligase human double minute 2, and we initially sought to characterize its activity in models of mantle cell lymphoma (MCL) and multiple myeloma (MM). Serdemetan induced a dose-dependent inhibition of proliferation in both wild-type (wt) and mutant (mut) p53 cell lines, with IC50 values from 0.25 to 3 μM/l, in association with an S phase cell cycle arrest. Caspase-3 activation was primarily seen in wtp53-bearing cells but also occurred in mutp53-bearing cells, albeit to a lesser extent. 293T cells treated with JNJ-26854165 and serdemetan-resistant fibroblasts displayed accumulation of cholesterol within endosomes, a phenotype reminiscent of that seen in the ATP-binding cassette subfamily A member-1 (ABCA1) cholesterol transport disorder, Tangiers disease. MM and MCL cells had decreased cholesterol efflux and electron microscopy demonstrated the accumulation of lipid whorls, confirming the lysosomal storage disease phenotype. JNJ-26854165 induced induction of cholesterol regulatory genes, sterol regulatory element-binding transcription factor-1 and -2, liver X receptors α and β, along with increased expression of Niemann-Pick disease type-C1 and -C2. However, JNJ-26854165 induced enhanced ABCA1 turnover despite enhancing transcription. Finally, ABCA1 depletion resulted in enhanced sensitivity to JNJ-26854165. Overall, these findings support the hypothesis that serdemetan functions in part by inhibiting cholesterol transport and that this pathway is a potential new target for the treatment of MCL and MM.
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Affiliation(s)
- Richard J Jones
- The Department of Lymphoma and Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas 77054, USA
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130
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Chapuy-Regaud S, Subra C, Requena M, de Medina P, Amara S, Delton-Vandenbroucke I, Payre B, Cazabat M, Carriere F, Izopet J, Poirot M, Record M. Progesterone and a phospholipase inhibitor increase the endosomal bis(monoacylglycero)phosphate content and block HIV viral particle intercellular transmission. Biochimie 2013; 95:1677-88. [PMID: 23774297 DOI: 10.1016/j.biochi.2013.05.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 05/27/2013] [Indexed: 10/26/2022]
Abstract
Progesterone, the cationic amphiphile U18666A and a phospholipase inhibitor (Methyl Arachidonyl Fluoro Phosphonate, MAFP) inhibited by 70%-90% HIV production in viral reservoir cells, i.e. human THP-1 monocytes and monocyte-derived macrophages (MDM). These compounds triggered an inhibition of fluid phase endocytosis (macropinocytosis) and modified cellular lipid homeostasis since endosomes accumulated filipin-stained sterols and Bis(Monoacylglycero)Phosphate (BMP). BMP was quantified using a new cytometry procedure and was increased by 1.25 times with MAFP, 1.7 times with U18666A and 2.5 times with progesterone. MAFP but not progesterone or U18666A inhibited the hydrolysis of BMP by the Pancreatic Lipase Related Protein 2 (PLRP2) as shown by in-vitro experiments. The possible role of sterol transporters in steroid-mediated BMP increase is discussed. Electron microscopy showed the accumulation of viral particles either into large intracellular viral-containing compartments or outside the cells, indicating that endosomal accumulation of BMP could block intracellular biogenesis of viral particles while inhibition of macropinocytosis would prevent viral particle uptake. This is the first report linking BMP metabolism with a natural steroid such as progesterone or with involvement of a phospholipase A1 activity. BMP cellular content could be used as a biomarker for efficient anti-viral drugs.
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Affiliation(s)
- Sabine Chapuy-Regaud
- INSERM, U1043, Equipe Infection virales: persistance, réponse de l'hôte et physiopathologie, Toulouse F-31300, France
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131
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Fu R, Wassif CA, Yanjanin NM, Watkins-Chow DE, Baxter LL, Incao A, Liscum L, Sidhu R, Firnkes S, Graham M, Ory DS, Porter FD, Pavan WJ. Efficacy of N-acetylcysteine in phenotypic suppression of mouse models of Niemann-Pick disease, type C1. Hum Mol Genet 2013; 22:3508-23. [PMID: 23666527 DOI: 10.1093/hmg/ddt206] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Niemann-Pick disease, type C1 (NPC1), which arises from a mutation in the NPC1 gene, is characterized by abnormal cellular storage and transport of cholesterol and other lipids that leads to hepatic disease and progressive neurological impairment. Oxidative stress has been hypothesized to contribute to the NPC1 disease pathological cascade. To determine whether treatments reducing oxidative stress could alleviate NPC1 disease phenotypes, the in vivo effects of the antioxidant N-acetylcysteine (NAC) on two mouse models for NPC1 disease were studied. NAC was able to partially suppress phenotypes in both antisense-induced (NPC1ASO) and germline (Npc1-/-) knockout genetic mouse models, confirming the presence of an oxidative stress-related mechanism in progression of NPC1 phenotypes and suggesting NAC as a potential molecule for treatment. Gene expression analyses of NAC-treated NPC1ASO mice suggested NAC affects pathways distinct from those initially altered by Npc1 knockdown, data consistent with NAC achieving partial disease phenotype suppression. In a therapeutic trial of short-term NAC administration to NPC1 patients, no significant effects on oxidative stress in these patients were identified other than moderate improvement of the fraction of reduced CoQ10, suggesting limited efficacy of NAC monotherapy. However, the mouse model data suggest that the distinct antioxidant effects of NAC could provide potential treatment of NPC1 disease, possibly in concert with other therapeutic molecules at earlier stages of disease progression. These data also validated the NPC1ASO mouse as an efficient model for candidate NPC1 drug screening, and demonstrated similarities in hepatic phenotypes and genome-wide transcript expression patterns between the NPC1ASO and Npc1-/- models.
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Affiliation(s)
- Rao Fu
- Department of Health and Human Services, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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132
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Shoemaker CJ, Schornberg KL, Delos SE, Scully C, Pajouhesh H, Olinger GG, Johansen LM, White JM. Multiple cationic amphiphiles induce a Niemann-Pick C phenotype and inhibit Ebola virus entry and infection. PLoS One 2013; 8:e56265. [PMID: 23441171 PMCID: PMC3575416 DOI: 10.1371/journal.pone.0056265] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 01/07/2013] [Indexed: 12/11/2022] Open
Abstract
Ebola virus (EBOV) is an enveloped RNA virus that causes hemorrhagic fever in humans and non-human primates. Infection requires internalization from the cell surface and trafficking to a late endocytic compartment, where viral fusion occurs, providing a conduit for the viral genome to enter the cytoplasm and initiate replication. In a concurrent study, we identified clomiphene as a potent inhibitor of EBOV entry. Here, we screened eleven inhibitors that target the same biosynthetic pathway as clomiphene. From this screen we identified six compounds, including U18666A, that block EBOV infection (IC50 1.6 to 8.0 µM) at a late stage of entry. Intriguingly, all six are cationic amphiphiles that share additional chemical features. U18666A induces phenotypes, including cholesterol accumulation in endosomes, associated with defects in Niemann–Pick C1 protein (NPC1), a late endosomal and lysosomal protein required for EBOV entry. We tested and found that all six EBOV entry inhibitors from our screen induced cholesterol accumulation. We further showed that higher concentrations of cationic amphiphiles are required to inhibit EBOV entry into cells that overexpress NPC1 than parental cells, supporting the contention that they inhibit EBOV entry in an NPC1-dependent manner. A previously reported inhibitor, compound 3.47, inhibits EBOV entry by blocking binding of the EBOV glycoprotein to NPC1. None of the cationic amphiphiles tested had this effect. Hence, multiple cationic amphiphiles (including several FDA approved agents) inhibit EBOV entry in an NPC1-dependent fashion, but by a mechanism distinct from that of compound 3.47. Our findings suggest that there are minimally two ways of perturbing NPC1-dependent pathways that can block EBOV entry, increasing the attractiveness of NPC1 as an anti-filoviral therapeutic target.
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Affiliation(s)
- Charles J. Shoemaker
- Departmentof Cell Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Kathryn L. Schornberg
- Departmentof Cell Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Sue E. Delos
- Departmentof Cell Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Corinne Scully
- U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, United States of America
| | - Hassan Pajouhesh
- Zalicus Inc., Cambridge, Massachusetts, United States of America
| | - Gene G. Olinger
- U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Maryland, United States of America
| | - Lisa M. Johansen
- Zalicus Inc., Cambridge, Massachusetts, United States of America
| | - Judith M. White
- Departmentof Cell Biology, University of Virginia, Charlottesville, Virginia, United States of America
- Departmentof Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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133
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Choi BR, Lee J, Kim SY, Yim I, Kim EH, Woo HJ. Prion protein conversion induced by trivalent iron in vesicular trafficking. Biochem Biophys Res Commun 2013; 432:539-44. [PMID: 23416082 DOI: 10.1016/j.bbrc.2013.02.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 02/06/2013] [Indexed: 11/19/2022]
Abstract
Iron dyshomeostasis has been observed in prion diseases; however, little is known regarding the contribution of the oxidation state of iron to prion protein (PrP) conversion. In this study, PrP(C)-deficient HpL3-4 cells were exposed to divalent [Fe(II)] or trivalent [Fe(III)] iron, followed by exogenous recombinant PrP (rPrP) treatment. We then analyzed the accumulation of internalized rPrP and its biochemical properties, including its resistance to both proteinase K (PK) digestion and detergent solubility. Fe(III), but not Fe(II), induced the accumulation of internalized rPrP, which was partially converted to detergent-insoluble and PK-resistant PrP (PrP(res)). The Fe(III)-induced PrP(res) generation required an intact cell structure, and it was hindered by U18666A, an inhibitor of vesicular trafficking, but not by NH4Cl, an inhibitor of endolysosomal acidification. These observations implicated that the Fe(III)-mediated PrP(res) conversion likely occurs during endosomal vesicular trafficking rather than in the acidic environment of lysosomes.
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Affiliation(s)
- Bo-Ran Choi
- Laboratory of Immunology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea
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134
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Gilk SD, Cockrell DC, Luterbach C, Hansen B, Knodler LA, Ibarra JA, Steele-Mortimer O, Heinzen RA. Bacterial colonization of host cells in the absence of cholesterol. PLoS Pathog 2013; 9:e1003107. [PMID: 23358892 PMCID: PMC3554619 DOI: 10.1371/journal.ppat.1003107] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 11/16/2012] [Indexed: 12/21/2022] Open
Abstract
Reports implicating important roles for cholesterol and cholesterol-rich lipid rafts in host-pathogen interactions have largely employed sterol sequestering agents and biosynthesis inhibitors. Because the pleiotropic effects of these compounds can complicate experimental interpretation, we developed a new model system to investigate cholesterol requirements in pathogen infection utilizing DHCR24−/− mouse embryonic fibroblasts (MEFs). DHCR24−/− MEFs lack the Δ24 sterol reductase required for the final enzymatic step in cholesterol biosynthesis, and consequently accumulate desmosterol into cellular membranes. Defective lipid raft function by DHCR24−/− MEFs adapted to growth in cholesterol-free medium was confirmed by showing deficient uptake of cholera-toxin B and impaired signaling by epidermal growth factor. Infection in the absence of cholesterol was then investigated for three intracellular bacterial pathogens: Coxiella burnetii, Salmonella enterica serovar Typhimurium, and Chlamydia trachomatis. Invasion by S. Typhimurium and C. trachomatis was unaltered in DHCR24−/− MEFs. In contrast, C. burnetii entry was significantly decreased in −cholesterol MEFs, and also in +cholesterol MEFs when lipid raft-associated αVβ3 integrin was blocked, suggesting a role for lipid rafts in C. burnetii uptake. Once internalized, all three pathogens established their respective vacuolar niches and replicated normally. However, the C. burnetii-occupied vacuole within DHCR24−/− MEFs lacked the CD63-postive material and multilamellar membranes typical of vacuoles formed in wild type cells, indicating cholesterol functions in trafficking of multivesicular bodies to the pathogen vacuole. These data demonstrate that cholesterol is not essential for invasion and intracellular replication by S. Typhimurium and C. trachomatis, but plays a role in C. burnetii-host cell interactions. Clustered receptors associated with cholesterol-rich microdomains, termed lipid rafts, are thought to provide plasma membrane signaling platforms that bacterial pathogens can subvert to gain entry into host cells. Moreover, cholesterol has been implicated as a critical structural lipid of several pathogen-occupied vacuoles. Cumulative data supporting these models have principally been derived using inhibitors of cholesterol metabolism and various sterol sequestering compounds, agents that can lack specificity and cause unwanted cellular affects. Here, we employed a new system to investigate pathogen reliance on cholesterol for host cell colonization that utilizes mouse embryonic fibroblasts that can synthesize precursor sterols, but not cholesterol. Cells lacking cholesterol displayed strong defects in lipid raft-based signaling. However, no defects were observed in entry, vacuole development, and growth of Salmonella enterica and Chlamydia trachomatis, bacterial pathogens previously shown to rely on cholesterol for optimal host cell parasitism. Entry by Coxiella burnetii, the bacterial cause of human Q fever, was significantly decreased in cholesterol-negative cells as was trafficking of membranous material to the pathogen vacuole. However, subsequent bacterial replication was unaltered. Our results should prompt a reevaluation of the overall importance of cholesterol in bacterial pathogenesis with the described experimental system providing an alternative approach for such studies.
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Affiliation(s)
- Stacey D. Gilk
- Coxiella Pathogenesis Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Diane C. Cockrell
- Coxiella Pathogenesis Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Courtney Luterbach
- Salmonella-Host Cell Interactions Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Bryan Hansen
- Microscopy Unit, Research Technology Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Leigh A. Knodler
- Salmonella-Host Cell Interactions Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - J. Antonio Ibarra
- Salmonella-Host Cell Interactions Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Olivia Steele-Mortimer
- Salmonella-Host Cell Interactions Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Robert A. Heinzen
- Coxiella Pathogenesis Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail:
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135
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Nunes MJ, Moutinho M, Gama MJ, Rodrigues CMP, Rodrigues E. Histone deacetylase inhibition decreases cholesterol levels in neuronal cells by modulating key genes in cholesterol synthesis, uptake and efflux. PLoS One 2013; 8:e53394. [PMID: 23326422 PMCID: PMC3542332 DOI: 10.1371/journal.pone.0053394] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 11/28/2012] [Indexed: 12/14/2022] Open
Abstract
Cholesterol is an essential component of the central nervous system and increasing evidence suggests an association between brain cholesterol metabolism dysfunction and the onset of neurodegenerative disorders. Interestingly, histone deacetylase inhibitors (HDACi) such as trichostatin A (TSA) are emerging as promising therapeutic approaches in neurodegenerative diseases, but their effect on brain cholesterol metabolism is poorly understood. We have previously demonstrated that HDACi up-regulate CYP46A1 gene transcription, a key enzyme in neuronal cholesterol homeostasis. In this study, TSA was shown to modulate the transcription of other genes involved in cholesterol metabolism in human neuroblastoma cells, namely by up-regulating genes that control cholesterol efflux and down-regulating genes involved in cholesterol synthesis and uptake, thus leading to an overall decrease in total cholesterol content. Furthermore, co-treatment with the amphipathic drug U18666A that can mimic the intracellular cholesterol accumulation observed in cells of Niemman-Pick type C patients, revealed that TSA can ameliorate the phenotype induced by pathological cholesterol accumulation, by restoring the expression of key genes involved in cholesterol synthesis, uptake and efflux and promoting lysosomal cholesterol redistribution. These results clarify the role of TSA in the modulation of neuronal cholesterol metabolism at the transcriptional level, and emphasize the idea of HDAC inhibition as a promising therapeutic tool in neurodegenerative disorders with impaired cholesterol metabolism.
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Affiliation(s)
- Maria João Nunes
- Research Institute for Medicines and Pharmaceutical Sciences iMed.UL, Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal
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136
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Silvente-Poirot S, Poirot M. Cholesterol epoxide hydrolase and cancer. Curr Opin Pharmacol 2012; 12:696-703. [DOI: 10.1016/j.coph.2012.07.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 07/09/2012] [Accepted: 07/11/2012] [Indexed: 10/28/2022]
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137
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Canfrán-Duque A, Casado ME, Pastor O, Sánchez-Wandelmer J, de la Peña G, Lerma M, Mariscal P, Bracher F, Lasunción MA, Busto R. Atypical antipsychotics alter cholesterol and fatty acid metabolism in vitro. J Lipid Res 2012; 54:310-24. [PMID: 23175778 DOI: 10.1194/jlr.m026948] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Haloperidol, a typical antipsychotic, has been shown to inhibit cholesterol biosynthesis by affecting Δ(7)-reductase, Δ(8,7)-isomerase, and Δ(14)-reductase activities, which results in the accumulation of different sterol intermediates. In the present work, we investigated the effects of atypical or second-generation antipsychotics (SGA), such as clozapine, risperidone, and ziprasidone, on intracellular lipid metabolism in different cell lines. All the SGAs tested inhibited cholesterol biosynthesis. Ziprasidone and risperidone had the same targets as haloperidol at inhibiting cholesterol biosynthesis, although with different relative activities (ziprasidone > haloperidol > risperidone). In contrast, clozapine mainly affected Δ(24)-reductase and Δ(8,7)-isomerase activities. These amphiphilic drugs also interfered with the LDL-derived cholesterol egress from the endosome/lysosome compartment, thus further reducing the cholesterol content in the endoplasmic reticulum. This triggered a homeostatic response with the stimulation of sterol regulatory element-binding protein (SREBP)-regulated gene expression. Treatment with SGAs also increased the synthesis of complex lipids (phospholipids and triacylglycerides). Once the antipsychotics were removed from the medium, a rebound in the cholesterol biosynthesis rate was detected, and the complex-lipid synthesis further increased. In this condition, apolipoprotein B secretion was also stimulated as demonstrated in HepG2 cells. These effects of SGAs on lipid homeostasis may be relevant in the metabolic side effects of antipsychotics, especially hypertriglyceridemia.
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Affiliation(s)
- Alberto Canfrán-Duque
- Servicio de Bioquímica-Investigación, Hospital Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
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138
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Herman GE, Kratz L. Disorders of sterol synthesis: beyond Smith-Lemli-Opitz syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2012; 160C:301-21. [PMID: 23042573 DOI: 10.1002/ajmg.c.31340] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Since the discovery in 1993 that Smith-Lemli-Opitz syndrome (SLOS) is a disorder of cholesterol biosynthesis, human disorders associated with additional enzymes involved in the conversion of lanosterol to cholesterol have been identified. This review will focus primarily on the clinical aspects of these disorders, highlighting newly described syndromes, such as SC4MOL deficiency and CK syndrome. We will also provide clinical descriptions of additional cases for extremely rare disorders, such as desmosterolosis. We will compare and contrast the findings with those found in SLOS and briefly discuss possible mechanisms of disease pathogenesis.
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Affiliation(s)
- Gail E Herman
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children's Hospital, 700 Children's Dr. Rm W403, Columbus, OH 43205, USA.
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139
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Friedrich BM, Trefry JC, Biggins JE, Hensley LE, Honko AN, Smith DR, Olinger GG. Potential vaccines and post-exposure treatments for filovirus infections. Viruses 2012; 4:1619-50. [PMID: 23170176 PMCID: PMC3499823 DOI: 10.3390/v4091619] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 08/31/2012] [Accepted: 09/04/2012] [Indexed: 01/07/2023] Open
Abstract
Viruses of the family Filoviridae represent significant health risks as emerging infectious diseases as well as potentially engineered biothreats. While many research efforts have been published offering possibilities toward the mitigation of filoviral infection, there remain no sanctioned therapeutic or vaccine strategies. Current progress in the development of filovirus therapeutics and vaccines is outlined herein with respect to their current level of testing, evaluation, and proximity toward human implementation, specifically with regard to human clinical trials, nonhuman primate studies, small animal studies, and in vitro development. Contemporary methods of supportive care and previous treatment approaches for human patients are also discussed.
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Affiliation(s)
- Brian M. Friedrich
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702, USA; (B.M.F.); (J.C.T.); (J.E.B.); (A.N.H.); (D.R.S.)
| | - John C. Trefry
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702, USA; (B.M.F.); (J.C.T.); (J.E.B.); (A.N.H.); (D.R.S.)
| | - Julia E. Biggins
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702, USA; (B.M.F.); (J.C.T.); (J.E.B.); (A.N.H.); (D.R.S.)
| | - Lisa E. Hensley
- United States Food and Drug Administration (FDA), Medical Science Countermeasures Initiative (McMi), 10903 New Hampshire Avenue, Silver Spring, MD 20901, USA; (L.E.H.)
| | - Anna N. Honko
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702, USA; (B.M.F.); (J.C.T.); (J.E.B.); (A.N.H.); (D.R.S.)
| | - Darci R. Smith
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702, USA; (B.M.F.); (J.C.T.); (J.E.B.); (A.N.H.); (D.R.S.)
| | - Gene G. Olinger
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702, USA; (B.M.F.); (J.C.T.); (J.E.B.); (A.N.H.); (D.R.S.)
- Author to whom correspondence should be addressed; (G.G.O.); Tel.: +1-301-619-8581; +1-301-619-2290
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Patent Highlights. Pharm Pat Anal 2012. [DOI: 10.4155/ppa.12.44] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A snapshot of recent key developments in the patent literature of relevance to the advancement of pharmaceutical and medical R&D
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Shurtleff AC, Nguyen TL, Kingery DA, Bavari S. Therapeutics for filovirus infection: traditional approaches and progress towards in silico drug design. Expert Opin Drug Discov 2012; 7:935-54. [PMID: 22873527 DOI: 10.1517/17460441.2012.714364] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Ebolaviruses and marburgviruses cause severe and often lethal human hemorrhagic fevers. As no FDA-approved therapeutics are available for these infections, efforts to discover new therapeutics are important, especially because these pathogens are considered biothreats and emerging infectious diseases. All methods for discovering new therapeutics should be considered, including compound library screening in vitro against virus and in silico structure-based drug design, where possible, if sufficient biochemical and structural information is available. AREAS COVERED This review covers the structure and function of filovirus proteins, as they have been reported to date, as well as some of the current antiviral screening approaches. The authors discuss key studies mapping small-molecule modulators that were found through library and in silico screens to potential sites on viral proteins or host proteins involved in virus trafficking and pathogenesis. A description of ebolavirus and marburgvirus diseases and available animal models is also presented. EXPERT OPINION To discover novel therapeutics with potent efficacy using sophisticated computational methods, more high-resolution crystal structures of filovirus proteins and more details about the protein functions and host interaction will be required. Current compound screening efforts are finding active antiviral compounds, but an emphasis on discovery research to investigate protein structures and functions enabling in silico drug design would provide another avenue for finding antiviral molecules. Additionally, targeting of protein-protein interactions may be a future avenue for drug discovery since disrupting catalytic sites may not be possible for all proteins.
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Affiliation(s)
- Amy C Shurtleff
- U.S. Army Medical Research Institute of Infectious Diseases, Integrated Toxicology Division, Fort Detrick, 1425 Porter Street, Frederick, MD 21702, USA.
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Ribas GS, Pires R, Coelho JC, Rodrigues D, Mescka CP, Vanzin CS, Biancini GB, Negretto G, Wayhs CA, Wajner M, Vargas CR. Oxidative stress in Niemann‐Pick type C patients: a protective role of N‐butyl‐deoxynojirimycin therapy. Int J Dev Neurosci 2012; 30:439-44. [DOI: 10.1016/j.ijdevneu.2012.07.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/03/2012] [Accepted: 07/11/2012] [Indexed: 01/22/2023] Open
Affiliation(s)
- Graziela S. Ribas
- Programa de Pós‐Graduação em Ciências FarmacêuticasUFRGSIpiranga 2752Porto AlegreRS90610‐000Brazil
- Serviço de Genética MédicaHCPARamiro Barcelos 2350Porto AlegreRS90035‐903Brazil
| | - Ricardo Pires
- Programa de Pós‐Graduação em Genética e Toxicologia AplicadaULBRAAv. Farroupilha 8001CanoasRS92425‐900Brazil
| | - Janice Carneiro Coelho
- Programa de Pós‐Graduação em Ciências Biológicas: BioquímicaUFRGSRamiro Barcelos 2600 anexoPorto AlegreRS90035‐003Brazil
| | - Daiane Rodrigues
- Serviço de Genética MédicaHCPARamiro Barcelos 2350Porto AlegreRS90035‐903Brazil
| | - Caroline Paula Mescka
- Serviço de Genética MédicaHCPARamiro Barcelos 2350Porto AlegreRS90035‐903Brazil
- Programa de Pós‐Graduação em Ciências Biológicas: BioquímicaUFRGSRamiro Barcelos 2600 anexoPorto AlegreRS90035‐003Brazil
| | - Camila S. Vanzin
- Serviço de Genética MédicaHCPARamiro Barcelos 2350Porto AlegreRS90035‐903Brazil
- Programa de Pós‐Graduação em Ciências Biológicas: BioquímicaUFRGSRamiro Barcelos 2600 anexoPorto AlegreRS90035‐003Brazil
| | - Giovana B. Biancini
- Serviço de Genética MédicaHCPARamiro Barcelos 2350Porto AlegreRS90035‐903Brazil
- Programa de Pós‐Graduação em Ciências Biológicas: BioquímicaUFRGSRamiro Barcelos 2600 anexoPorto AlegreRS90035‐003Brazil
| | - Giovanna Negretto
- Programa de Pós‐Graduação em Ciências FarmacêuticasUFRGSIpiranga 2752Porto AlegreRS90610‐000Brazil
- Serviço de Genética MédicaHCPARamiro Barcelos 2350Porto AlegreRS90035‐903Brazil
| | - Carlos A.Y. Wayhs
- Programa de Pós‐Graduação em Ciências FarmacêuticasUFRGSIpiranga 2752Porto AlegreRS90610‐000Brazil
- Serviço de Genética MédicaHCPARamiro Barcelos 2350Porto AlegreRS90035‐903Brazil
| | - Moacir Wajner
- Serviço de Genética MédicaHCPARamiro Barcelos 2350Porto AlegreRS90035‐903Brazil
- Programa de Pós‐Graduação em Ciências Biológicas: BioquímicaUFRGSRamiro Barcelos 2600 anexoPorto AlegreRS90035‐003Brazil
| | - Carmen R. Vargas
- Serviço de Genética MédicaHCPARamiro Barcelos 2350Porto AlegreRS90035‐903Brazil
- Programa de Pós‐Graduação em Ciências Biológicas: BioquímicaUFRGSRamiro Barcelos 2600 anexoPorto AlegreRS90035‐003Brazil
- Departamento de Análises, Faculdade de FarmáciaUFRGSIpiranga 2752Porto AlegreRS90610‐000Brazil
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β-amyloid inhibits protein prenylation and induces cholesterol sequestration by impairing SREBP-2 cleavage. J Neurosci 2012; 32:6490-500. [PMID: 22573671 DOI: 10.1523/jneurosci.0630-12.2012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Accumulation of β-amyloid (Aβ) inside brain neurons is an early and crucial event in Alzheimer's disease (AD). Studies in brains of AD patients and mice models of AD suggested that cholesterol homeostasis is altered in neurons that accumulate Aβ. Here we directly investigated the role of intracellular oligomeric Aβ(42) (oAβ(42)) in neuronal cholesterol homeostasis. We report that oAβ(42) induces cholesterol sequestration without increasing cellular cholesterol mass. Several features of AD, such as endosomal abnormalities, brain accumulation of Aβ and neurofibrillary tangles, and influence of apolipoprotein E genotype, are also present in Niemann-Pick type C, a disease characterized by impairment of intracellular cholesterol trafficking. These common features and data presented here suggest that a pathological mechanism involving abnormal cholesterol trafficking could take place in AD. Cholesterol sequestration in Aβ-treated neurons results from impairment of intracellular cholesterol trafficking secondary to inhibition of protein prenylation. oAβ(42) reduces sterol regulatory element-binding protein-2 (SREBP-2) cleavage, causing decrease of protein prenylation. Inhibition of protein prenylation represents a mechanism of oAβ(42)-induced neuronal death. Supply of the isoprenoid geranylgeranyl pyrophosphate to oAβ(42)-treated neurons recovers normal protein prenylation, reduces cholesterol sequestration, and prevents Aβ-induced neurotoxicity. Significant to AD, reduced levels of protein prenylation are present in the cerebral cortex of the TgCRND8 mouse model. In conclusion, we demonstrate a significant inhibitory effect of Aβ on protein prenylation and identify SREBP-2 as a target of oAβ(42), directly linking Aβ to cholesterol homeostasis impairment.
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Logan R, Funk RS, Axcell E, Krise JP. Drug-drug interactions involving lysosomes: mechanisms and potential clinical implications. Expert Opin Drug Metab Toxicol 2012; 8:943-58. [PMID: 22616667 DOI: 10.1517/17425255.2012.691165] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Many commercially available, weakly basic drugs have been shown to be lysosomotropic, meaning they are subject to extensive sequestration in lysosomes through an ion trapping-type mechanism. The extent of lysosomal trapping of a drug is an important therapeutic consideration because it can influence both activity and pharmacokinetic disposition. The administration of certain drugs can alter lysosomes such that their accumulation capacity for co-administered and/or secondarily administered drugs is altered. AREAS COVERED In this review the authors explore what is known regarding the mechanistic basis for drug-drug interactions involving lysosomes. Specifically, the authors address the influence of drugs on lysosomal pH, volume and lipid processing. EXPERT OPINION Many drugs are known to extensively accumulate in lysosomes and significantly alter their structure and function; however, the therapeutic and toxicological implications of this remain controversial. The authors propose that drug-drug interactions involving lysosomes represent an important potential source of variability in drug activity and pharmacokinetics. Most evaluations of drug-drug interactions involving lysosomes have been performed in cultured cells and isolated tissues. More comprehensive in vivo evaluations are needed to fully explore the impact of this drug-drug interaction pathway on therapeutic outcomes.
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Affiliation(s)
- Randall Logan
- The University of Kansas, Department of Pharmaceutical Chemistry, 2095 Constant Ave., Lawrence, KS 66047, USA
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Abstract
Chlamydia species are obligate intracellular pathogens that are important causes of human genital tract, ocular and respiratory infections. The bacteria replicate within a specialized membrane-bound compartment termed the inclusion and require host-derived lipids for intracellular growth and development. Emerging evidence indicates that Chlamydia has evolved clever strategies to fulfil its lipid needs by interacting with multiple host cell compartments and redirecting trafficking pathways to its intracellular niche. In this review, we highlight recent findings that have significantly expanded our understanding of how Chlamydia exploit lipid trafficking pathways to ensure the survival of this important human pathogen.
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Affiliation(s)
- Cherilyn A Elwell
- Departments of Medicine, University of California, San Francisco, CA, USA.
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Abstract
Intracellular cholesterol amounts, distribution and traffic are tightly regulated to maintain the healthy eukaryotic cell function. However, how intracellular pathogens that require cholesterol, interact with the host cholesterol homeostasis and traffic is not well understood. Anaplasma phagocytophilum is an obligatory intracellular and cholesterol-robbing bacterium, which causes human granulocytic anaplasmosis. Here we found that a subset of cholesterol-binding membrane protein, Niemann-Pick type C1 (NPC1)-bearing vesicles devoid of lysosomal markers were upregulated in HL-60 cells infected with A. phagocytophilum, and trafficked to live bacterial inclusions. The NPC1 localization to A. phagocytophilum inclusions was abolished by low-density lipoprotein (LDL)-derived cholesterol traffic inhibitor U18666A. Studies using NPC1 siRNA and the cell line with cholesterol traffic defect demonstrated that the NPC1 function is required for bacterial cholesterol acquisition and infection. Furthermore, trans-Golgi network-specific soluble N-ethylmaleimide-sensitive factor attachment protein receptors, vesicle-associated membrane protein (VAMP4) and syntaxin 16, which are associated with NPC1 and LDL-derived cholesterol vesicular transport were recruited to A. phagocytophilum inclusions, and VAMP4 was required for bacteria infection. Taken together, A. phagocytophilum is the first example of a pathogen that subverts the NPC1 pathway of intracellular cholesterol transport and homeostasis for bacterial inclusion membrane biogenesis and cholesterol capture.
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Affiliation(s)
- Qingming Xiong
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA.
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Cabeza C, Figueroa A, Lazo OM, Galleguillos C, Pissani C, Klein A, Gonzalez-Billault C, Inestrosa NC, Alvarez AR, Zanlungo S, Bronfman FC. Cholinergic abnormalities, endosomal alterations and up-regulation of nerve growth factor signaling in Niemann-Pick type C disease. Mol Neurodegener 2012; 7:11. [PMID: 22458984 PMCID: PMC3395862 DOI: 10.1186/1750-1326-7-11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 03/29/2012] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Neurotrophins and their receptors regulate several aspects of the developing and mature nervous system, including neuronal morphology and survival. Neurotrophin receptors are active in signaling endosomes, which are organelles that propagate neurotrophin signaling along neuronal processes. Defects in the Npc1 gene are associated with the accumulation of cholesterol and lipids in late endosomes and lysosomes, leading to neurodegeneration and Niemann-Pick type C (NPC) disease. The aim of this work was to assess whether the endosomal and lysosomal alterations observed in NPC disease disrupt neurotrophin signaling. As models, we used i) NPC1-deficient mice to evaluate the central cholinergic septo-hippocampal pathway and its response to nerve growth factor (NGF) after axotomy and ii) PC12 cells treated with U18666A, a pharmacological cellular model of NPC, stimulated with NGF. RESULTS NPC1-deficient cholinergic cells respond to NGF after axotomy and exhibit increased levels of choline acetyl transferase (ChAT), whose gene is under the control of NGF signaling, compared to wild type cholinergic neurons. This finding was correlated with increased ChAT and phosphorylated Akt in basal forebrain homogenates. In addition, we found that cholinergic neurons from NPC1-deficient mice had disrupted neuronal morphology, suggesting early signs of neurodegeneration. Consistently, PC12 cells treated with U18666A presented a clear NPC cellular phenotype with a prominent endocytic dysfunction that includes an increased size of TrkA-containing endosomes and reduced recycling of the receptor. This result correlates with increased sensitivity to NGF, and, in particular, with up-regulation of the Akt and PLC-γ signaling pathways, increased neurite extension, increased phosphorylation of tau protein and cell death when PC12 cells are differentiated and treated with U18666A. CONCLUSIONS Our results suggest that the NPC cellular phenotype causes neuronal dysfunction through the abnormal up-regulation of survival pathways, which causes the perturbation of signaling cascades and anomalous phosphorylation of the cytoskeleton.
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Affiliation(s)
- Carolina Cabeza
- Physiology Department, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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Ordonez MP, Roberts EA, Kidwell CU, Yuan SH, Plaisted WC, Goldstein LSB. Disruption and therapeutic rescue of autophagy in a human neuronal model of Niemann Pick type C1. Hum Mol Genet 2012; 21:2651-62. [PMID: 22437840 DOI: 10.1093/hmg/dds090] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
An unresolved issue about many neurodegenerative diseases is why neurons are particularly sensitive to defects in ubiquitous cellular processes. One example is Niemann Pick type C1, caused by defects in cholesterol trafficking in all cells, but where neurons are preferentially damaged. Understanding this selective failure is limited by the difficulty in obtaining live human neurons from affected patients. To solve this problem, we generated neurons with decreased function of NPC1 from human embryonic stem cells and used them to test the hypothesis that defective cholesterol handling leads to enhanced pathological phenotypes in neurons. We found that human NPC1 neurons have strong spontaneous activation of autophagy, and, contrary to previous reports in patient fibroblasts, a block of autophagic progression leading to defective mitochondrial clearance. Mitochondrial fragmentation is an exceptionally severe phenotype in NPC1 neurons compared with fibroblasts, causing abnormal accumulation of mitochondrial proteins. Contrary to expectation, these abnormal phenotypes were rescued by treatment with the autophagy inhibitor 3-methyladenine and by treatment with the potential therapeutic cyclodextrin, which mobilizes cholesterol from the lysosomal compartment. Our findings suggest that neurons are especially sensitive to lysosomal cholesterol accumulation because of autophagy disruption and accumulation of fragmented mitochondria, thus defining a new route to effective drug development for NPC1 disease.
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Affiliation(s)
- M Paulina Ordonez
- Department of Cellular and Molecular Medicine, Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA 92093, USA
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Roszell BR, Tao JQ, Yu KJ, Huang S, Bates SR. Characterization of the Niemann-Pick C pathway in alveolar type II cells and lamellar bodies of the lung. Am J Physiol Lung Cell Mol Physiol 2012; 302:L919-32. [PMID: 22367786 DOI: 10.1152/ajplung.00383.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Niemann-Pick C (NPC) pathway plays an essential role in the intracellular trafficking of cholesterol by facilitating the release of lipoprotein-derived sterol from the lumen of lysosomes. Regulation of cellular cholesterol homeostasis is of particular importance to lung alveolar type II cells because of the need for production of surfactant with an appropriate lipid composition. We performed microscopic and biochemical analysis of NPC proteins in isolated rat type II pneumocytes. NPC1 and NPC2 proteins were present in the lung, isolated type II cells in culture, and alveolar macrophages. The glycosylated and nonglycosylated forms of NPC1 were prominent in the lung and the lamellar body organelles. Immunocytochemical analysis of isolated type II pneumocytes showed localization of NPC1 to the limiting membrane of lamellar bodies. NPC2 and lysosomal acid lipase were found within these organelles, as confirmed by z-stack analysis of confocal images. All three proteins also were identified in small, lysosome-like vesicles. In the presence of serum, pharmacological inhibition of the NPC pathway with compound U18666A resulted in doubling of the cholesterol content of the type II cells. Filipin staining revealed a striking accumulation of cholesterol within lamellar bodies. Thus the NPC pathway functions to control cholesterol accumulation in lamellar bodies of type II pneumocytes and, thereby, may play a role in the regulation of surfactant cholesterol content.
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Affiliation(s)
- Blair R Roszell
- Institute for Environmental Medicine, Univ. of Pennsylvania, Philadelphia, PA 19104-6068, USA
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Lange Y, Ye J, Steck TL. Activation mobilizes the cholesterol in the late endosomes-lysosomes of Niemann Pick type C cells. PLoS One 2012; 7:e30051. [PMID: 22276143 PMCID: PMC3262792 DOI: 10.1371/journal.pone.0030051] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 12/12/2011] [Indexed: 11/18/2022] Open
Abstract
A variety of intercalating amphipaths increase the chemical activity of plasma membrane cholesterol. To test whether intracellular cholesterol can be similarly activated, we examined NPC1 and NPC2 fibroblasts, since they accumulate large amounts of cholesterol in their late endosomes and lysosomes (LE/L). We gauged the mobility of intracellular sterol from its appearance at the surface of the intact cells, as determined by its susceptibility to cholesterol oxidase and its isotope exchange with extracellular 2-(hydroxypropyl)-β-cyclodextrin-cholesterol. The entire cytoplasmic cholesterol pool in these cells was mobile, exchanging with the plasma membrane with an apparent half-time of ∼3–4 hours, ∼4–5 times slower than that for wild type human fibroblasts (half-time ∼0.75 hours). The mobility of the intracellular cholesterol was increased by the membrane-intercalating amphipaths chlorpromazine and 1-octanol. Chlorpromazine also promoted the net transfer of LE/L cholesterol to serum and cyclodextrin. Surprisingly, the mobility of LE/L cholesterol was greatly stimulated by treating intact NPC cells with glutaraldehyde or formaldehyde. Similar effects were seen with wild type fibroblasts in which the LE/L cholesterol pool had been expanded using U18666A. We also showed that the cholesterol in the intracellular membranes of fixed wild-type fibroblasts was mobile; it was rapidly oxidized by cholesterol oxidase and was rapidly replenished by exogenous sterol. We conclude that a) the cholesterol in NPC cells can exit the LE/L (and the extensive membranous inclusions therein) over a few hours; b) this mobility is stimulated by the activation of the cholesterol with intercalating amphipaths; c) intracellular cholesterol is even more mobile in fixed cells; and d) amphipaths that activate cholesterol might be useful in treating NPC disease.
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Affiliation(s)
- Yvonne Lange
- Department of Pathology, Rush University Medical Center, Chicago, Illinois, United States of America.
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