1
|
Bhatnagar A, Chopra U, Raja S, Das KD, Mahalingam S, Chakravortty D, Srinivasula SM. TLR-mediated aggresome-like induced structures comprise antimicrobial peptides and attenuate intracellular bacterial survival. Mol Biol Cell 2024; 35:ar34. [PMID: 38170582 PMCID: PMC10916861 DOI: 10.1091/mbc.e23-09-0347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 12/07/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024] Open
Abstract
Immune cells employ diverse mechanisms for host defense. Macrophages, in response to TLR activation, assemble aggresome-like induced structures (ALIS). Our group has shown TLR4-signaling transcriptionally upregulates p62/sequestome1, which assembles ALIS. We have demonstrated that TLR4-mediated autophagy is, in fact, selective-autophagy of ALIS. We hypothesize that TLR-mediated autophagy and ALIS contribute to host-defense. Here we show that ALIS are assembled in macrophages upon exposure to different bacteria. These structures are associated with pathogen-containing phagosomes. Importantly, we present evidence of increased bacterial burden, where ALIS assembly is prevented with p62-specific siRNA. We have employed 3D-super-resolution structured illumination microscopy (3D-SR-SIM) and mass-spectrometric (MS) analyses to gain insight into the assembly of ALIS. Ultra-structural analyses of known constituents of ALIS (p62, ubiquitin, LC3) reveal that ALIS are organized structures with distinct patterns of alignment. Furthermore, MS-analyses of ALIS identified, among others, several proteins of known antimicrobial properties. We have validated MS data by testing the association of some of these molecules (Bst2, IFITM2, IFITM3) with ALIS and the phagocytosed-bacteria. We surmise that AMPs enrichment in ALIS leads to their delivery to bacteria-containing phagosomes and restricts the bacteria. Our findings in this paper support hitherto unknown functions of ALIS in host-defense.
Collapse
Affiliation(s)
- Anushree Bhatnagar
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram 695551, Kerala, India
| | - Umesh Chopra
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Sebastian Raja
- Laboratory of Molecular Cell Biology, Department of Biotechnology, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Krishanu Dey Das
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram 695551, Kerala, India
| | - S. Mahalingam
- Laboratory of Molecular Cell Biology, Department of Biotechnology, Indian Institute of Technology-Madras, Chennai 600036, India
| | - Dipshikha Chakravortty
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram 695551, Kerala, India
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Srinivasa Murty Srinivasula
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram 695551, Kerala, India
| |
Collapse
|
2
|
Pawar P, Gokavi J, Wakhare S, Bagul R, Ghule U, Khan I, Ganu V, Mukherjee A, Shete A, Rao A, Saxena V. MiR-155 Negatively Regulates Anti-Viral Innate Responses among HIV-Infected Progressors. Viruses 2023; 15:2206. [PMID: 38005883 PMCID: PMC10675553 DOI: 10.3390/v15112206] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 09/28/2023] [Accepted: 10/02/2023] [Indexed: 11/26/2023] Open
Abstract
HIV infection impairs host immunity, leading to progressive disease. An anti-retroviral treatment efficiently controls viremia but cannot completely restore the immune dysfunction in HIV-infected individuals. Both host and viral factors determine the rate of disease progression. Among the host factors, innate immunity plays a critical role; however, the mechanism(s) associated with dysfunctional innate responses are poorly understood among HIV disease progressors, which was investigated here. The gene expression profiles of TLRs and innate cytokines in HIV-infected (LTNPs and progressors) and HIV-uninfected individuals were examined. Since the progressors showed a dysregulated TLR-mediated innate response, we investigated the role of TLR agonists in restoring the innate functions of the progressors. The stimulation of PBMCs with TLR3 agonist-poly:(I:C), TLR7 agonist-GS-9620 and TLR9 agonist-ODN 2216 resulted in an increased expression of IFN-α, IFN-β and IL-6. Interestingly, the expression of IFITM3, BST-2, IFITM-3, IFI-16 was also increased upon stimulation with TLR3 and TLR7 agonists, respectively. To further understand the molecular mechanism involved, the role of miR-155 was explored. Increased miR-155 expression was noted among the progressors. MiR-155 inhibition upregulated the expression of TLR3, NF-κB, IRF-3, TNF-α and the APOBEC-3G, IFITM-3, IFI-16 and BST-2 genes in the PBMCs of the progressors. To conclude, miR-155 negatively regulates TLR-mediated cytokines as wel l as the expression of host restriction factors, which play an important role in mounting anti-HIV responses; hence, targeting miR-155 might be helpful in devising strategic approaches towards alleviating HIV disease progression.
Collapse
Affiliation(s)
- Puja Pawar
- Division of Immunology and Serology, ICMR-National AIDS Research Institute, Pune 411026, India; (P.P.); (J.G.); (S.W.); (V.G.); (A.S.)
| | - Jyotsna Gokavi
- Division of Immunology and Serology, ICMR-National AIDS Research Institute, Pune 411026, India; (P.P.); (J.G.); (S.W.); (V.G.); (A.S.)
| | - Shilpa Wakhare
- Division of Immunology and Serology, ICMR-National AIDS Research Institute, Pune 411026, India; (P.P.); (J.G.); (S.W.); (V.G.); (A.S.)
| | - Rajani Bagul
- Division of Clinical Sciences, ICMR-National AIDS Research Institute, Pune 411026, India; (R.B.); (U.G.); (A.R.)
| | - Ujjwala Ghule
- Division of Clinical Sciences, ICMR-National AIDS Research Institute, Pune 411026, India; (R.B.); (U.G.); (A.R.)
| | - Ishrat Khan
- Division of Virology, ICMR-National AIDS Research Institute, Pune 411026, India; (I.K.); (A.M.)
| | - Varada Ganu
- Division of Immunology and Serology, ICMR-National AIDS Research Institute, Pune 411026, India; (P.P.); (J.G.); (S.W.); (V.G.); (A.S.)
| | - Anupam Mukherjee
- Division of Virology, ICMR-National AIDS Research Institute, Pune 411026, India; (I.K.); (A.M.)
| | - Ashwini Shete
- Division of Immunology and Serology, ICMR-National AIDS Research Institute, Pune 411026, India; (P.P.); (J.G.); (S.W.); (V.G.); (A.S.)
| | - Amrita Rao
- Division of Clinical Sciences, ICMR-National AIDS Research Institute, Pune 411026, India; (R.B.); (U.G.); (A.R.)
| | - Vandana Saxena
- Division of Immunology and Serology, ICMR-National AIDS Research Institute, Pune 411026, India; (P.P.); (J.G.); (S.W.); (V.G.); (A.S.)
| |
Collapse
|
3
|
Kong Y, Xue Z, Wang H, Cui G, Chen A, Liu J, Wang J, Li X, Huang B. Identification of BST2 Contributing to the Development of Glioblastoma Based on Bioinformatics Analysis. Front Genet 2022; 13:890174. [PMID: 35865015 PMCID: PMC9294273 DOI: 10.3389/fgene.2022.890174] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 06/15/2022] [Indexed: 11/22/2022] Open
Abstract
Rigorous molecular analysis of the immune cell environment and immune response of human tumors has led to immune checkpoint inhibitors as one of the most promising strategies for the treatment of human cancer. However, in human glioblastoma multiforme (GBM) which develops in part by attracting immune cell types intrinsic to the human brain (microglia), standard immunotherapy has yielded inconsistent results in experimental models and patients. Here, we analyzed publicly available expression datasets to identify molecules possibly associated with immune response originating from or influencing the tumor microenvironment in primary tumor samples. Using three glioma datasets (GSE16011, Rembrandt-glioma and TCGA-glioma), we first analyzed the data to distinguish between GBMs of high and low tumor cell purity, a reflection of the cellular composition of the tumor microenvironment, and second, to identify differentially expressed genes (DEGs) between these two groups using GSEA and other analyses. Tumor purity was negatively correlated with patient prognosis. The interferon gamma-related gene BST2 emerged as a DEG that was highly expressed in GBM and negatively correlated with tumor purity. BST2high tumors also tended to harbor PTEN mutations (31 vs. 9%, BST2high versus BST2low) while BST2low tumors more often had sustained TP53 mutations (8 versus 36%, BST2high versus BST2low). Prognosis of patients with BST2high tumors was also poor relative to patients with BST2low tumors. Further molecular in silico analysis demonstrated that high expression of BST2 was negatively correlated with CD8+ T cells but positively correlated with macrophages with an M2 phenotype. Further functional analysis demonstrated that BST2 was associated with multiple immune checkpoints and cytokines, and may promote tumorigenesis and progression through interferon gamma, IL6/JAK/STAT3 signaling, IL2/STAT5 signaling and the TNF-α signaling via NF-kB pathway. Finally, a series of experiments confirmed that the expression of BST2 can be significantly increased by IFN induction, and knockdown of BST2 can significantly inhibit the growth and invasion of GBM cells, and may affect the phenotype of tumor-associated macrophages. In conclusion, BST2 may promote the progression of GBM and may be a target for treatment.
Collapse
Affiliation(s)
- Yang Kong
- Department of Neurosurgery, Qilu Hospital, Cheeloo College of Medicine and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, China
- Jinan Microecological Biomedicine Shandong Laboratory and Shandong Key Laboratory of Brain Function Remodeling, Jinan, China
- Neurological Care Unit, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China
- Department of Neurosurgery, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China
| | - Zhiwei Xue
- Department of Neurosurgery, Qilu Hospital, Cheeloo College of Medicine and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, China
- Jinan Microecological Biomedicine Shandong Laboratory and Shandong Key Laboratory of Brain Function Remodeling, Jinan, China
| | - Haiying Wang
- Department of Anesthesiology, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China
| | - Guangqiang Cui
- Neurological Care Unit, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China
- Department of Neurosurgery, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China
| | - Anjing Chen
- Department of Neurosurgery, Qilu Hospital, Cheeloo College of Medicine and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, China
- Jinan Microecological Biomedicine Shandong Laboratory and Shandong Key Laboratory of Brain Function Remodeling, Jinan, China
| | - Jie Liu
- Neurological Care Unit, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China
- Department of Neurosurgery, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China
| | - Jian Wang
- Department of Neurosurgery, Qilu Hospital, Cheeloo College of Medicine and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, China
- Jinan Microecological Biomedicine Shandong Laboratory and Shandong Key Laboratory of Brain Function Remodeling, Jinan, China
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Xingang Li
- Department of Neurosurgery, Qilu Hospital, Cheeloo College of Medicine and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, China
- Jinan Microecological Biomedicine Shandong Laboratory and Shandong Key Laboratory of Brain Function Remodeling, Jinan, China
| | - Bin Huang
- Department of Neurosurgery, Qilu Hospital, Cheeloo College of Medicine and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, China
- Jinan Microecological Biomedicine Shandong Laboratory and Shandong Key Laboratory of Brain Function Remodeling, Jinan, China
- *Correspondence: Bin Huang,
| |
Collapse
|
4
|
Bone marrow stromal antigen 2 (BST-2) genetic variants influence expression levels and disease outcome in HIV-1 chronically infected patients. Retrovirology 2022; 19:3. [PMID: 35081977 PMCID: PMC8793201 DOI: 10.1186/s12977-022-00588-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 01/11/2022] [Indexed: 11/26/2022] Open
Abstract
Background Bone marrow stromal antigen 2 (BST-2) also known as Tetherin (CD317/HM1.24), is a host restriction factor that blocks the release of HIV-1 virions from infected cells. Previous studies reported that BST-2 genetic variants or single nucleotide polymorphims (SNPs) have a preventative role during HIV-1 infection. However, the influence of BST-2 SNPs on expression levels remains unknown. In this study, we investigated the influence of BST-2 SNPs on expression levels and disease outcome in HIV-1 subtype C chronically infected antiretroviral therapy naïve individuals. Results We quantified BST-2 mRNA levels in peripheral blood mononuclear cells (PBMCs), determined BST-2 protein expression on the surface of CD4+ T cells using flow cytometry and genotyped two intronic single nucleotide polymorphisms (SNPs) rs919267 and rs919266 together with one SNP rs9576 located in the 3’ untranslated region (UTR) of bst-2 gene using TaqMan assays from HIV-1 uninfected and infected participants. Subsequently, we determined the ability of plasma antibody levels to mediate antibody-dependent cellular phagocytosis (ADCP) using gp120 consensus C and p24 subtype B/C protein. Fc receptor-mediated NK cell degranulation was evaluated as a surrogate for ADCC activity using plasma from HIV-1 positive participants. BST-2 mRNA expression levels in PBMCs and protein levels on CD4+ T cells were lower in HIV-1 infected compared to uninfected participants (p = 0.075 and p < 0.001, respectively). rs919267CT (p = 0.042) and rs919267TT (p = 0.045) were associated with lower BST-2 mRNA expression levels compared to rs919267CC in HIV-1 uninfected participants. In HIV-1 infected participants, rs919267CT associated with lower CD4 counts, (p = 0.003), gp120-IgG1 (p = 0.040), gp120-IgG3 (p = 0.016) levels but higher viral loads (p = 0.001) while rs919267TT was associated with lower BST-2 mRNA levels (p = 0.046), CD4 counts (p = 0.001), gp120-IgG1 levels (p = 0.033) but higher plasma viral loads (p = 0.007). Conversely, rs9576CA was associated with higher BST-2 mRNA expression levels (p = 0.027), CD4 counts (p = 0.079), gp120-IgG1 (p = 0.009), gp120-IgG3 (p = 0.039) levels but with lower viral loads (p = 0.037). Conclusion Our findings show that bst-2 SNPs mediate BST-2 expression and disease outcome, correlate with gp120-IgG1, gp120-IgG3 levels but not p24-IgG levels, ADCC and ADCP activity. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s12977-022-00588-2.
Collapse
|
5
|
Singh R, Ramsuran V, Naranbhai V, Yende-Zuma N, Garrett N, Mlisana K, Dong KL, Walker BD, Abdool Karim SS, Carrington M, Ndung'u T. Epigenetic Regulation of BST-2 Expression Levels and the Effect on HIV-1 Pathogenesis. Front Immunol 2021; 12:669241. [PMID: 34025670 PMCID: PMC8131512 DOI: 10.3389/fimmu.2021.669241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 04/20/2021] [Indexed: 11/23/2022] Open
Abstract
HIV-1 must overcome host antiviral restriction factors for efficient replication. We hypothesized that elevated levels of bone marrow stromal cell antigen 2 (BST-2), a potent host restriction factor that interferes with HIV-1 particle release in some human cells and is antagonized by the viral protein Vpu, may associate with viral control. Using cryopreserved samples, from HIV-1 seronegative and seropositive Black women, we measured in vitro expression levels of BST-2 mRNA using a real-time PCR assay and protein levels were validated by Western blotting. The expression level of BST-2 showed an association with viral control within two independent cohorts of Black HIV infected females (r=-0.53, p=0.015, [n =21]; and r=-0.62, p=0.0006, [n=28]). DNA methylation was identified as a mechanism regulating BST-2 levels, where increased BST-2 methylation results in lower expression levels and associates with worse HIV disease outcome. We further demonstrate the ability to regulate BST-2 levels using a DNA hypomethylation drug. Our results suggest BST-2 as a factor for potential therapeutic intervention against HIV and other diseases known to involve BST-2.
Collapse
Affiliation(s)
- Ravesh Singh
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.,Africa Health Research Institute (AHRI), Durban, South Africa.,Department of Microbiology, National Health Laboratory Services, KZN Academic Complex, Inkosi Albert Luthuli Central Hospital, Durban, South Africa
| | - Veron Ramsuran
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa.,The Ragon Institute of MGH, MIT and Harvard University, Cambridge, MA, United States.,Basic Science Program, Frederick National Laboratory for Cancer Research in the Laboratory of Integrative Cancer Immunology, Bethesda, MD, United States.,Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
| | - Vivek Naranbhai
- The Ragon Institute of MGH, MIT and Harvard University, Cambridge, MA, United States.,Basic Science Program, Frederick National Laboratory for Cancer Research in the Laboratory of Integrative Cancer Immunology, Bethesda, MD, United States.,Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
| | - Nonhlanhla Yende-Zuma
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
| | - Nigel Garrett
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
| | - Koleka Mlisana
- Department of Microbiology, National Health Laboratory Services, KZN Academic Complex, Inkosi Albert Luthuli Central Hospital, Durban, South Africa
| | - Krista L Dong
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Bruce D Walker
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.,Africa Health Research Institute (AHRI), Durban, South Africa.,The Ragon Institute of MGH, MIT and Harvard University, Cambridge, MA, United States
| | - Salim S Abdool Karim
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), University of KwaZulu-Natal, Durban, South Africa
| | - Mary Carrington
- The Ragon Institute of MGH, MIT and Harvard University, Cambridge, MA, United States.,Basic Science Program, Frederick National Laboratory for Cancer Research in the Laboratory of Integrative Cancer Immunology, Bethesda, MD, United States
| | - Thumbi Ndung'u
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.,Africa Health Research Institute (AHRI), Durban, South Africa.,The Ragon Institute of MGH, MIT and Harvard University, Cambridge, MA, United States.,Max Planck Institute for Infection Biology, Chariteplatz, Berlin, Germany.,Division of Infection and Immunity, University College London, London, United Kingdom
| |
Collapse
|
6
|
Abstract
The cellular surfaceome and its residing extracellularly exposed proteins are involved in a multitude of molecular signaling processes across the viral infection cycle. Successful viral propagation, including viral entry, immune evasion, virion release and viral spread rely on dynamic molecular interactions with the surfaceome. Decoding of these viral-host surfaceome interactions using advanced technologies enabled the discovery of fundamental new functional insights into cellular and viral biology. In this review, we highlight recently developed experimental strategies, with a focus on spatial proteotyping technologies, aiding in the rational design of theranostic strategies to combat viral infections.
Collapse
|
7
|
Bortlik M, Copertino DC, Brailey PM, Beckerle GA, Ormsby CE, Rosenberg MG, Wiznia AA, Raposo RAS, Nixon DF, de Mulder Rougvie M. Restriction Factor Expression in Vertically Infected Children Living With HIV-1. Pediatr Infect Dis J 2021; 40:144-146. [PMID: 33395209 DOI: 10.1097/inf.0000000000002924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Around 1.7 million children are estimated to live with HIV-1 worldwide, and about 160,000 infants are newly infected every year. Since adaptive immunity takes time to mature and develop in infants, and maternal antibodies provide limited antiviral activity, innate and intrinsic immunity against HIV-1 in the young is of critical importance. Intrinsic restriction factors are cellular proteins that effectively inhibit HIV-1 replication in vitro, but there is limited understanding of their role in vivo, and little to no data has been reported on the expression of host restriction factors in children. We hypothesized that restriction factor expression might be particularly important in children living with HIV-1 and correlate with disease progression. METHODS We analyzed gene expression of APOBEC3A, APOBEC3C, APOBEC3G, APOBEC3H, SAMHD1, ISG15, CDKN1A, MX2, TRIM5, and SLFN11 by qPCR in 121 samples of CD4+ T cells from vertically infected children living with HIV-1. Cell surface expression of BST-2/tetherin and markers of CD4+ T-cell activation were analyzed by flow cytometry. RESULTS After adjusting for gender and age, BST-2/tetherin expression on CD4+ T cells showed significant positive correlation with viral load (P = 0.0006; ρ = 0.33), CD4+ T-cell activation (P < 0.0001; ρ = 0.53), CD8+ T-cell activation (P < 0.0001; ρ = 0.53), and a negative correlation with CD4+ T-cell counts (P = 0.0008; ρ = -0.33). The expression of SAMHD1 correlated negatively with markers of T-cell activation (P = 0.046; ρ = -0.22). DISCUSSION These results suggest an important role of some restriction factors in the pathogenesis of HIV-1 in children.
Collapse
Affiliation(s)
- Martin Bortlik
- From the Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC
- Faculty of Medicine in Hradec Kralove, Charles University, Prague, Czech Republic
- Department of Dermatology, Military University Hospital, Prague, Czech Republic
| | - Dennis C Copertino
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY
| | - Phillip M Brailey
- From the Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC
- The Peter Gorer Department of Immunology, King's College, London, United Kingdom
- The Francis Crick Institute, London, United Kingdom
| | - Greta A Beckerle
- From the Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY
| | - Christopher E Ormsby
- Centre for Research in Infectious Diseases (CIENI), National Institute of Respiratory Diseases (INER), Mexico City, CDMX, Mexico
| | - Michael G Rosenberg
- Department of Pediatrics, Division of Infectious Diseases, Jacobi Medical Center, Bronx, NY
- Albert Einstein College of Medicine, Bronx, New York, NY
| | - Andrew A Wiznia
- Albert Einstein College of Medicine, Bronx, New York, NY
- Department of Pediatrics, Division of Allergy-Immunology, Jacobi Medical Center, Bronx, NY
| | - Rui André Saraiva Raposo
- From the Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC
| | - Douglas F Nixon
- From the Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY
| | - Miguel de Mulder Rougvie
- From the Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, New York, NY
| |
Collapse
|
8
|
Maali Y, Journo C, Mahieux R, Dutartre H. Microbial Biofilms: Human T-cell Leukemia Virus Type 1 First in Line for Viral Biofilm but Far Behind Bacterial Biofilms. Front Microbiol 2020; 11:2041. [PMID: 33042035 PMCID: PMC7523422 DOI: 10.3389/fmicb.2020.02041] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/03/2020] [Indexed: 12/25/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus associated with adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). To date, it is the unique published example of a virus able to form a biofilm at the surface of infected cells. Deeply studied in bacteria, bacterial biofilms represent multicellular assemblies of bacteria in contact with a surface and shielded by the extracellular matrix (ECM). Microbial lifestyle in biofilms, either viral or bacterial, is opposed structurally and physiologically to an isolated lifestyle, in which viruses or bacteria freely float in their environment. HTLV-1 biofilm formation is believed to be promoted by viral proteins, mainly Tax, through remodeling of the ECM of the infected cells. HTLV-1 biofilm has been linked to cell-to-cell transmission of the virus. However, in comparison to bacterial biofilms, very little is known on kinetics of viral biofilm formation or dissemination, but also on its pathophysiological roles, such as escape from immune detection or therapeutic strategies, as well as promotion of leukemogenesis. The switch between production of cell-free isolated virions and cell-associated viral biofilm, although not fully apprehended yet, remains a key step to understand HTLV-1 infection and pathogenesis.
Collapse
Affiliation(s)
- Yousef Maali
- CIRI - Centre International de Recherche en Infectiologie, Univ Lyon, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Lyon, France
| | - Chloé Journo
- CIRI - Centre International de Recherche en Infectiologie, Univ Lyon, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Lyon, France
| | - Renaud Mahieux
- CIRI - Centre International de Recherche en Infectiologie, Univ Lyon, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Lyon, France
| | - Hélène Dutartre
- CIRI - Centre International de Recherche en Infectiologie, Univ Lyon, Université Claude Bernard Lyon 1, Inserm, U1111, CNRS, UMR5308, ENS Lyon, Lyon, France
| |
Collapse
|
9
|
Antiviral Activity and Adaptive Evolution of Avian Tetherins. J Virol 2020; 94:JVI.00416-20. [PMID: 32238588 DOI: 10.1128/jvi.00416-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 03/26/2020] [Indexed: 02/07/2023] Open
Abstract
Tetherin/BST-2 is an antiviral protein that blocks the release of enveloped viral particles by linking them to the membrane of producing cells. At first, BST-2 genes were described only in humans and other mammals. Recent work identified BST-2 orthologs in nonmammalian vertebrates, including birds. Here, we identify the BST-2 sequence in domestic chicken (Gallus gallus) for the first time and demonstrate its activity against avian sarcoma and leukosis virus (ASLV). We generated a BST-2 knockout in chicken cells and showed that BST-2 is a major determinant of an interferon-induced block of ASLV release. Ectopic expression of chicken BST-2 blocks the release of ASLV in chicken cells and of human immunodeficiency virus type 1 (HIV-1) in human cells. Using metabolic labeling and pulse-chase analysis of HIV-1 Gag proteins, we verified that chicken BST-2 blocks the virus at the release stage. Furthermore, we describe BST-2 orthologs in multiple avian species from 12 avian orders. Previously, some of these species were reported to lack BST-2, highlighting the difficulty of identifying sequences of this extremely variable gene. We analyzed BST-2 genes in the avian orders Galliformes and Passeriformes and showed that they evolve under positive selection. This indicates that avian BST-2 is involved in host-virus evolutionary arms races and suggests that BST-2 antagonists exist in some avian viruses. In summary, we show that chicken BST-2 has the potential to act as a restriction factor against ASLV. Characterizing the interaction of avian BST-2 with avian viruses is important in understanding innate antiviral defenses in birds.IMPORTANCE Birds are important hosts of viruses that have the potential to cause zoonotic infections in humans. However, only a few antiviral genes (called viral restriction factors) have been described in birds, mostly because birds lack counterparts of highly studied mammalian restriction factors. Tetherin/BST-2 is a restriction factor, originally described in humans, that blocks the release of newly formed virus particles from infected cells. Recent work identified BST-2 in nonmammalian vertebrate species, including birds. Here, we report the BST-2 sequence in domestic chicken and describe its antiviral activity against a prototypical avian retrovirus, avian sarcoma and leukosis virus (ASLV). We also identify BST-2 genes in multiple avian species and show that they evolve rapidly in birds, which is an important indication of their relevance for antiviral defense. Analysis of avian BST-2 genes will shed light on defense mechanisms against avian viral pathogens.
Collapse
|
10
|
Coindre S, Tchitchek N, Alaoui L, Vaslin B, Bourgeois C, Goujard C, Lecuroux C, Bruhns P, Le Grand R, Beignon AS, Lambotte O, Favier B. Mass Cytometry Analysis Reveals Complex Cell-State Modifications of Blood Myeloid Cells During HIV Infection. Front Immunol 2019; 10:2677. [PMID: 31824485 PMCID: PMC6882910 DOI: 10.3389/fimmu.2019.02677] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 10/30/2019] [Indexed: 01/04/2023] Open
Abstract
Dendritic cells (DC), which are involved in orchestrating early immune responses against pathogens, are dysregulated in their function by HIV infection. This dysregulation likely contributes to tip the balance toward viral persistence. Different DC subpopulations, including classical (cDCs) and plasmacytoid (pDCs) dendritic cells, are subjected to concomitant inflammatory and immunoregulatory events during HIV infection, which hampers the precise characterization of their regulation through classical approaches. Here, we carried out mass cytometry analysis of blood samples from early HIV-infected patients that were longitudinally collected before and after 1 year of effective combination antiretroviral therapy (cART). Blood samples from HIV controller patients who naturally control the infection were also included. Our data revealed that plasma HIV RNA level was positively associated with a loss of cDC and pDC subpopulations that display high expression of LILR immunomodulatory receptors. Conversely, specific monocyte populations co-expressing high levels of HLA-I, 3 immunomodulatory receptors, CD64, LILRA2, and LILRB4, and the restriction factor CD317 (also known as BST2/Tetherin), were more abundant in early HIV-infection. Finally, our analysis revealed that the blood of HIV controller patients contained in a higher abundance a particular subtype of CD1c+ cDCs, characterized by elevated co-expression of CD32b inhibitory receptor and HLA-DR antigen-presentation molecules. Overall, this study unravels the modifications induced in DC and monocyte subpopulations in different HIV+ conditions, and provides a better comprehension of the immune regulation/dysregulation mechanisms induced during this viral infection.
Collapse
Affiliation(s)
- Sixtine Coindre
- CEA-Université Paris Sud-INSERM U1184, IDMIT Department, IBFJ, DRF, Fontenay-aux-Roses, France
| | - Nicolas Tchitchek
- CEA-Université Paris Sud-INSERM U1184, IDMIT Department, IBFJ, DRF, Fontenay-aux-Roses, France
| | - Lamine Alaoui
- CEA-Université Paris Sud-INSERM U1184, IDMIT Department, IBFJ, DRF, Fontenay-aux-Roses, France
| | - Bruno Vaslin
- CEA-Université Paris Sud-INSERM U1184, IDMIT Department, IBFJ, DRF, Fontenay-aux-Roses, France
| | - Christine Bourgeois
- CEA-Université Paris Sud-INSERM U1184, IDMIT Department, IBFJ, DRF, Fontenay-aux-Roses, France
| | - Cecile Goujard
- Service de médecine interne et d'immunologie clinique, Hôpital Bicêtre, APHP, Le Kremlin Bicêtre, France.,INSERM U1018-Université Paris Sud, CESP (Centre for Research in Epidemiology and Population Health), Le Kremlin Bicêtre, France
| | - Camille Lecuroux
- CEA-Université Paris Sud-INSERM U1184, IDMIT Department, IBFJ, DRF, Fontenay-aux-Roses, France
| | - Pierre Bruhns
- Unit of Antibodies in Therapy and Pathology, Institut Pasteur, UMR1222 INSERM, Paris, France
| | - Roger Le Grand
- CEA-Université Paris Sud-INSERM U1184, IDMIT Department, IBFJ, DRF, Fontenay-aux-Roses, France
| | - Anne-Sophie Beignon
- CEA-Université Paris Sud-INSERM U1184, IDMIT Department, IBFJ, DRF, Fontenay-aux-Roses, France
| | - Olivier Lambotte
- CEA-Université Paris Sud-INSERM U1184, IDMIT Department, IBFJ, DRF, Fontenay-aux-Roses, France.,Service de médecine interne et d'immunologie clinique, Hôpital Bicêtre, APHP, Le Kremlin Bicêtre, France
| | - Benoit Favier
- CEA-Université Paris Sud-INSERM U1184, IDMIT Department, IBFJ, DRF, Fontenay-aux-Roses, France
| |
Collapse
|
11
|
Interplay between Intrinsic and Innate Immunity during HIV Infection. Cells 2019; 8:cells8080922. [PMID: 31426525 PMCID: PMC6721663 DOI: 10.3390/cells8080922] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 08/13/2019] [Accepted: 08/15/2019] [Indexed: 02/06/2023] Open
Abstract
Restriction factors are antiviral components of intrinsic immunity which constitute a first line of defense by blocking different steps of the human immunodeficiency virus (HIV) replication cycle. In immune cells, HIV infection is also sensed by several pattern recognition receptors (PRRs), leading to type I interferon (IFN-I) and inflammatory cytokines production that upregulate antiviral interferon-stimulated genes (ISGs). Several studies suggest a link between these two types of immunity. Indeed, restriction factors, that are generally interferon-inducible, are able to modulate immune responses. This review highlights recent knowledge of the interplay between restriction factors and immunity inducing antiviral defenses. Counteraction of this intrinsic and innate immunity by HIV viral proteins will also be discussed.
Collapse
|
12
|
Contribution of the Cytoplasmic Determinants of Vpu to the Expansion of Virus-Containing Compartments in HIV-1-Infected Macrophages. J Virol 2019; 93:JVI.00020-19. [PMID: 30867316 DOI: 10.1128/jvi.00020-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/09/2019] [Indexed: 12/30/2022] Open
Abstract
HIV-1 infection of macrophages leads to the sequestration of newly formed viruses in intracellular plasma membrane-connected structures termed virus-containing compartments (VCCs), where virions remain infectious and hidden from immune surveillance. The cellular restriction factor bone marrow stromal cell antigen 2 (BST2), which prevents HIV-1 dissemination by tethering budding viral particles at the plasma membrane, can be found in VCCs. The HIV-1 accessory protein Vpu counteracts the restriction factor BST2 by downregulating its expression and removing it from viral budding sites. Numerous studies described these Vpu countermeasures in CD4+ T cells or model cell lines, but the interplay between Vpu and BST2 in VCC formation and HIV-1 production in macrophages is less explored. Here, we show that Vpu expression in HIV-1-infected macrophages enhances viral release. This effect is related to Vpu's ability to circumvent BST2 antiviral activity. We show that in absence of Vpu, BST2 is enriched in VCCs and colocalizes with capsid p24, whereas Vpu expression significantly reduces the presence of BST2 in these compartments. Furthermore, our data reveal that BST2 is dispensable for the formation of VCCs and that Vpu expression impacts the volume of these compartments. This Vpu activity partly depends on BST2 expression and requires the integrity of the Vpu transmembrane domain, the dileucine-like motif E59XXXLV64 and phosphoserines 52 and 56 of Vpu. Altogether, these results highlight that Vpu controls the volume of VCCs and promotes HIV-1 release from infected macrophages.IMPORTANCE HIV-1 infection of macrophages leads to the sequestration of newly formed viruses in virus-containing compartments (VCCs), where virions remain infectious and hidden from immune surveillance. The restriction factor BST2, which prevents HIV-1 dissemination by tethering budding viral particles, can be found in VCCs. The HIV-1 Vpu protein counteracts BST2. This study explores the interplay between Vpu and BST2 in the viral protein functions on HIV-1 release and viral particle sequestration in VCCs in macrophages. The results show that Vpu controls the volume of VCCs and favors viral particle release. These Vpu functions partly depend on Vpu's ability to antagonize BST2. This study highlights that the transmembrane domain of Vpu and two motifs of the Vpu cytoplasmic domain are required for these functions. These motifs were notably involved in the control of the volume of VCCs by Vpu but were dispensable for the prevention of the specific accumulation of BST2 in these structures.
Collapse
|
13
|
Colomer-Lluch M, Ruiz A, Moris A, Prado JG. Restriction Factors: From Intrinsic Viral Restriction to Shaping Cellular Immunity Against HIV-1. Front Immunol 2018; 9:2876. [PMID: 30574147 PMCID: PMC6291751 DOI: 10.3389/fimmu.2018.02876] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/22/2018] [Indexed: 01/20/2023] Open
Abstract
Antiviral restriction factors are host cellular proteins that constitute a first line of defense blocking viral replication and propagation. In addition to interfering at critical steps of the viral replication cycle, some restriction factors also act as innate sensors triggering innate responses against infections. Accumulating evidence suggests an additional role for restriction factors in promoting antiviral cellular immunity to combat viruses. Here, we review the recent progress in our understanding on how restriction factors, particularly APOBEC3G, SAMHD1, Tetherin, and TRIM5α have the cell-autonomous potential to induce cellular resistance against HIV-1 while promoting antiviral innate and adaptive immune responses. Also, we provide an overview of how these restriction factors may connect with protein degradation pathways to modulate anti-HIV-1 cellular immune responses, and we summarize the potential of restriction factors-based therapeutics. This review brings a global perspective on the influence of restrictions factors in intrinsic, innate, and also adaptive antiviral immunity opening up novel research avenues for therapeutic strategies in the fields of drug discovery, gene therapy, and vaccines to control viral infections.
Collapse
Affiliation(s)
- Marta Colomer-Lluch
- IrsiCaixa AIDS Research Institute, Germans Trias i Pujol Research Institute, Universitat Autonoma de Barcelona, Badalona, Spain
| | - Alba Ruiz
- IrsiCaixa AIDS Research Institute, Germans Trias i Pujol Research Institute, Universitat Autonoma de Barcelona, Badalona, Spain
| | - Arnaud Moris
- Sorbonne Université, INSERM U1135, CNRS ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), Paris, France
| | - Julia G Prado
- IrsiCaixa AIDS Research Institute, Germans Trias i Pujol Research Institute, Universitat Autonoma de Barcelona, Badalona, Spain
| |
Collapse
|
14
|
Yamada E, Nakaoka S, Klein L, Reith E, Langer S, Hopfensperger K, Iwami S, Schreiber G, Kirchhoff F, Koyanagi Y, Sauter D, Sato K. Human-Specific Adaptations in Vpu Conferring Anti-tetherin Activity Are Critical for Efficient Early HIV-1 Replication In Vivo. Cell Host Microbe 2018; 23:110-120.e7. [PMID: 29324226 DOI: 10.1016/j.chom.2017.12.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 09/11/2017] [Accepted: 12/01/2017] [Indexed: 12/24/2022]
Abstract
The HIV-1-encoded accessory protein Vpu exerts several immunomodulatory functions, including counteraction of the host restriction factor tetherin, downmodulation of CD4, and inhibition of NF-κB activity to facilitate HIV-1 infection. However, the relative contribution of individual Vpu functions to HIV-1 infection in vivo remained unclear. Here, we used a humanized mouse model and HIV-1 strains with selective mutations in vpu to demonstrate that the anti-tetherin activity of Vpu is a prerequisite for efficient viral spread during the early phase of infection. Mathematical modeling and gain-of-function mutations in SIVcpz, the simian precursor of pandemic HIV-1, corroborate this finding. Blockage of interferon signaling combined with transcriptome analyses revealed that basal tetherin levels are sufficient to control viral replication. These results establish tetherin as a key effector of the intrinsic immune defense against HIV-1, and they demonstrate that Vpu-mediated tetherin antagonism is critical for efficient viral spread during the initial phase of HIV-1 replication.
Collapse
Affiliation(s)
- Eri Yamada
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan
| | - Shinji Nakaoka
- Institute of Industrial Sciences, The University of Tokyo, Tokyo 1538505, Japan; PRESTO, Japan Science and Technology Agency, Saitama 3320012, Japan
| | - Lukas Klein
- Institute of Molecular Virology, Ulm University Medical Center, Ulm 89081, Germany
| | - Elisabeth Reith
- Institute of Molecular Virology, Ulm University Medical Center, Ulm 89081, Germany
| | - Simon Langer
- Institute of Molecular Virology, Ulm University Medical Center, Ulm 89081, Germany
| | | | - Shingo Iwami
- PRESTO, Japan Science and Technology Agency, Saitama 3320012, Japan; CREST, Japan Science and Technology Agency, Saitama 3220012, Japan; Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 8128581, Japan
| | - Gideon Schreiber
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm 89081, Germany
| | - Yoshio Koyanagi
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan
| | - Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm 89081, Germany
| | - Kei Sato
- Laboratory of Systems Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 6068507, Japan; CREST, Japan Science and Technology Agency, Saitama 3220012, Japan.
| |
Collapse
|
15
|
T cells with low CD2 levels express reduced restriction factors and are preferentially infected in therapy naïve chronic HIV-1 patients. J Int AIDS Soc 2018; 20:21865. [PMID: 28953327 PMCID: PMC5964667 DOI: 10.7448/ias.20.1.21865] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
INTRODUCTION Restriction factors (RFs) suppress HIV-1 in cell lines and primary cell models. Hence, RFs might be attractive targets for novel antiviral strategies, but their importance for virus control in vivo is controversial. METHODS We profiled the expression of RFs in primary blood-derived mononuclear cells (PBMC) from therapy-naïve HIV-1 patients and quantified infection. RESULTS Overall, there was no correlation between individual RF expression and HIV-1 status in total PBMC. However, we identified a T cell population with low levels of intracellular CD2 and reduced expression of SAMHD1, p21 and SerinC5. CD2low T cells with reduced RF expression were markedly positive for HIV-1 p24. In contrast, CD2+ T cells were less infected and expressed higher levels of RFs. CD2low T cell infection correlated with viral loads and was associated with HIV-1 disease progression. CONCLUSIONS In untreated therapy naïve chronic HIV-1 patients, RF expression in T cells is associated with CD2 expression and seems to influence viral loads. Our study suggests that RFs help to control HIV-1 infection in certain T cells in vivo and supports the potential for RFs as promising targets for therapeutic intervention.
Collapse
|
16
|
Foster TL, Pickering S, Neil SJD. Inhibiting the Ins and Outs of HIV Replication: Cell-Intrinsic Antiretroviral Restrictions at the Plasma Membrane. Front Immunol 2018; 8:1853. [PMID: 29354117 PMCID: PMC5758531 DOI: 10.3389/fimmu.2017.01853] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/07/2017] [Indexed: 01/01/2023] Open
Abstract
Like all viruses, human immunodeficiency viruses (HIVs) and their primate lentivirus relatives must enter cells in order to replicate and, once produced, new virions need to exit to spread to new targets. These processes require the virus to cross the plasma membrane of the cell twice: once via fusion mediated by the envelope glycoprotein to deliver the viral core into the cytosol; and secondly by ESCRT-mediated scission of budding virions during release. This physical barrier thus presents a perfect location for host antiviral restrictions that target enveloped viruses in general. In this review we will examine the current understanding of innate host antiviral defences that inhibit these essential replicative steps of primate lentiviruses associated with the plasma membrane, the mechanism by which these viruses have adapted to evade such defences, and the role that this virus/host battleground plays in the transmission and pathogenesis of HIV/AIDS.
Collapse
Affiliation(s)
- Toshana L Foster
- Department of Infectious Disease, School of Immunology and Microbial Sciences, King's College London, London, United Kingdom
| | - Suzanne Pickering
- Department of Infectious Disease, School of Immunology and Microbial Sciences, King's College London, London, United Kingdom
| | - Stuart J D Neil
- Department of Infectious Disease, School of Immunology and Microbial Sciences, King's College London, London, United Kingdom
| |
Collapse
|
17
|
Hotter D, Kirchhoff F. Interferons and beyond: Induction of antiretroviral restriction factors. J Leukoc Biol 2017; 103:465-477. [PMID: 29345347 DOI: 10.1002/jlb.3mr0717-307r] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/25/2017] [Accepted: 09/26/2017] [Indexed: 12/18/2022] Open
Abstract
Antiviral restriction factors are structurally and functionally diverse cellular proteins that play a key role in the first line of defense against viral pathogens. Although many cell types constitutively express restriction factors at low levels, their induction in response to viral exposure and replication is often required for potent control and repulse of the invading pathogens. It is well established that type I IFNs efficiently induce antiviral restriction factors. Accumulating evidence suggests that other types of IFN, as well as specific cytokines, such as IL-27, and other activators of the cell are also capable of enhancing the expression of restriction factors and hence to establish an antiviral cellular state. Agents that efficiently induce restriction factors, increase their activity, and/or render them resistant against viral antagonists without causing general inflammation and significant side effects hold some promise for novel therapeutic or preventive strategies. In the present review, we summarize some of the current knowledge on the induction of antiretroviral restriction factors and perspectives for therapeutic application.
Collapse
Affiliation(s)
- Dominik Hotter
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Frank Kirchhoff
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| |
Collapse
|
18
|
Paliwal D, Joshi P, Panda SK. Hepatitis E Virus (HEV) egress: Role of BST2 (Tetherin) and interferon induced long non- coding RNA (lncRNA) BISPR. PLoS One 2017; 12:e0187334. [PMID: 29091957 PMCID: PMC5665557 DOI: 10.1371/journal.pone.0187334] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 10/18/2017] [Indexed: 12/18/2022] Open
Abstract
Background The biology of Hepatitis E Virus (HEV), a common cause of epidemic and sporadic hepatitis, is still being explored. HEV exits liver through bile, a process which is essential for its natural transmission by feco-oral route. Though the process of this polarised HEV egress is not known in detail, HEV pORF3 and hepatocyte actin cytoskeleton have been shown to play a role. Methods Our transcriptome analysis in Hepatitis E virus (HEV) replicon transfected Huh7 cells at 24 and 72 hrs indicated that at 24hrs, both LncBISPR and BST2, expressed by a bidirectional promoter were highly upregulated whereas at 72 hrs, BST2 expression was comparatively reduced accompanied by normal levels of BISPR. These findings were confirmed by qPCR analysis. Co-localisation of BST2 and HEV pORF2 was confirmed in HEV transfected Huh7 by confocal microscopy. To investigate the role of BISPR/BST2 in HEV life cycle, particularly virus egress, we generated Huh7 cells with ~8kb deletion in BISPR gene using Crispr-Cas9 system. The deletion was confirmed by PCR screening, Sanger sequencing and Real time PCR. Virus egress in ΔBISPR Huh7 and Huh7 cells was compared by measuring HEV positive strand RNA copy numbers in cell lysates and culture supernatants at 24 and 72 hrs post HEV replicon transfection and further validated by western blot for HEV pORF2 capsid protein. Results ΔBISPR Huh7 cells showed ~8 fold increase in virus egress at 24 hrs compared to Huh7 cells. No significant difference in virus egress was observed at 72hrs. Immunohistochemistry in histologically normal liver and HEV associated acute liver failure revealed BST2 overexpression in HEV infected hepatocytes and a dominant canalicular BST2 distribution in normal liver in addition to the cytoplasmic localisation reported in literature. Conclusions These findings lead us to believe that BISPR and BST2 may regulate egress of HEV virions into bile in vivo. This system may also be used to scale up virus production in vitro.
Collapse
Affiliation(s)
- Daizy Paliwal
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Prashant Joshi
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Subrat Kumar Panda
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
- * E-mail:
| |
Collapse
|
19
|
RICH2 is implicated in viraemic control of HIV-1 in black South African individuals. INFECTION GENETICS AND EVOLUTION 2017; 49:78-87. [PMID: 28069446 DOI: 10.1016/j.meegid.2017.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/22/2016] [Accepted: 01/05/2017] [Indexed: 11/22/2022]
Abstract
An intronic single nucleotide polymorphism (SNP) in RICH2 (rs2072255; 255i), in complete linkage disequilibrium (LD) with an exonic SNP (rs2072254; 254e), has been identified in a genome wide association study to be associated with progression to AIDS in Caucasian individuals. RICH2 links tetherin to the cortical actin network and the RICH2/tetherin interaction has been shown to be important for the downstream activation of NF-κβ and the consequential promotion of proinflammatory responses. We investigated the role of these two SNPs in natural control of HIV-1 in black South Africans including healthy controls (HCs; N=102) and antiretroviral-naive HIV-1-infected controllers (HICs; N=52) and progressors (N=74). HICs were stratified as elite controllers (ECs; N=11), viraemic controllers (VCs; N=30), high viral load (VL) long term non-progressors (HVL LTNPs; N=11) and also according to VL<400RNA copies/ml (HICs VL<400; N=20) and VL>400RNA copies/ml (HICs VL>400; N=32). Results showed that in contrast to Caucasians who had very strong LD between these SNPs (r2=0.97), black populations exhibited low LD (r2=0.11-0.27), however a 254e minor allele was always present with a 255i minor allele but not vice versa. The SNPs did not show significant over- or underrepresentation in any particular group, however the combination of 254e major allele homozygosity and 255i heterozygosity (254eAA/255iGA) was underrepresented in HICs (OR=3.26; P=0.04) and VCs (OR=7.77; P=0.02) compared to HCs, and in HICs VL>400 compared to both HCs (P=0.002) and progressors (P=0.02). A lower CD4+ T-cell count was associated with 254eAA/255iGA and 255i (GA+AA) in the total HIV-1-infected group (P=0.043) and progressors (P=0.017), respectively. In silico analysis predicted loss of an exonic splice enhancer site with the 254e-G allele. We postulate that altered splicing of RICH2 will affect levels of RICH2 expression and consequently NF-κβ activation. These findings point to a role for RICH2 and tetherin in viraemic natural control of HIV-1.
Collapse
|
20
|
Li SX, Barrett BS, Guo K, Santiago ML. Tetherin/BST-2: Restriction Factor or Immunomodulator? Curr HIV Res 2016; 14:235-46. [PMID: 26957198 DOI: 10.2174/1570162x14999160224102752] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 11/22/2022]
Abstract
BACKGROUND Cell-mediated immune (CMI) responses are critical for the control of HIV-1 infection and their importance was highlighted by the existence of viral proteins, particularly Vpu and Nef, that antagonize these responses. Pandemic HIV-1 Vpu counteracts Tetherin/BST-2, a host factor that could prevent the release of HIV-1 virions by tethering virions on the cell surface, but a link between Tetherin and HIV-1 CMI responses has not yet been demonstrated in vivo. In vitro, the virological and immunological impact of Tetherin-mediated accumulation of virions ranged from enhanced or diminished cell-to-cell spread to enhanced recognition by virus-specific antibodies for natural killer cellmediated lysis. However, Tetherin-restricted virions could be internalized through an endocytosis motif in the Tetherin cytoplasmic tail. METHODS Given the uncertainties on which in vitro results manifest in vivo and the dearth of knowledge on how Tetherin influences retroviral immunity, in vivo retrovirus infections in mice encoding wild-type, null and endocytosis-defective Tetherin were performed. Here, we review and highlight the results from these in vivo studies. RESULTS Current data suggests that endocytosis-defective Tetherin functions as a potent innate restriction factor. By contrast, endocytosis-competent Tetherin, the form found in most mammals including humans and the form counteracted by HIV-1 Vpu, was linked to stronger CMI responses in mice. CONCLUSION We propose that the main role of endocytosis-competent Tetherin is not to directly restrict retroviral replication, but to promote a more effective CMI response against retroviruses.
Collapse
Affiliation(s)
| | | | | | - Mario L Santiago
- Division of Infectious Diseases, University of Colorado Denver, Mail Stop B-168, 12700 E 19th Avenue, Aurora, CO 80045, USA.
| |
Collapse
|
21
|
Enhancing Virion Tethering by BST2 Sensitizes Productively and Latently HIV-infected T cells to ADCC Mediated by Broadly Neutralizing Antibodies. Sci Rep 2016; 6:37225. [PMID: 27853288 PMCID: PMC5112552 DOI: 10.1038/srep37225] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 10/26/2016] [Indexed: 02/01/2023] Open
Abstract
Binding of anti-HIV antibodies (Abs) to envelope (Env) glycoproteins on infected cells can mark them for elimination via antibody-dependent cell-mediated cytotoxicity (ADCC). BST2, a type I interferon (IFN)-stimulated restriction factor that anchors nascent Env-containing virions at the surface of infected cells has been shown to enhance ADCC functions. In a comprehensive analysis of ADCC potency by neutralizing anti-HIV Abs (NAbs), we show in this study that NAbs are capable of mediating ADCC against HIV-infected T cells with 3BNC117, PGT126 and PG9 being most efficient. We demonstrate that HIV-induced BST2 antagonism effectively attenuates Ab binding and ADCC responses mediated by all classes of NAbs that were tested. Interestingly, IFNα treatment can reverse this effect in a BST2-dependent manner. Importantly, while reactivated latent T cell lines display some susceptibility to ADCC mediated by broadly NAbs, inactivating BST2 viral countermeasures and/or exogenous IFNα augment their elimination. Overall, our findings support the notion that NAbs can induce ADCC. They highlight that while BST2 antagonism by HIV promotes ADCC evasion, strategies aimed at restoring BST2 restriction could improve anti-HIV responses and potentially provide a means to eliminate reactivated cells in latent reservoirs.
Collapse
|
22
|
Kong N, Meng Q, Wu Y, Wang Z, Zuo Y, Tong W, Zheng H, Li G, Yang S, Yu H, Shan T, Zhou EM, Tong G. Monoclonal Antibody to Bone Marrow Stromal Cell Antigen 2 Protein of Swine. Monoclon Antib Immunodiagn Immunother 2016; 35:172-6. [PMID: 27148642 DOI: 10.1089/mab.2016.0007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The bone marrow stromal cell antigen 2 (BST-2) protein was identified as a novel virus restriction factor that potently restricts the replication and egress of enveloped viruses. In this study, we generated monoclonal antibodies (MAbs) against porcine BST-2 encoding 34-112 aa of porcine BST-2, which was cloned and inserted into the prokaryotic expression vector pCold-I to construct a recombinant plasmid pCold-pBST-2. The recombinant porcine BST-2 protein (rpBST-2 protein) was induced by isopropyl-β-D-thiogalactoside in Escherichia coli BL21 (DE3). Then, BALB/c mice were immunized with the purified rpBST-2 protein to prepare MAbs of BST-2. After subcloning, one strain of hybridoma cells named 1B2 secreting porcine BST-2 protein monoclonal antibody (MAb) was obtained. Indirect immunofluorescence assay and western blot analysis showed that the MAb was specifically reacted with the overexpressed porcine BST-2 protein in Vero cells. The specific MAb of porcine BST-2 provides a valuable tool for further studies of BST-2 to restrict virus infection.
Collapse
Affiliation(s)
- Ning Kong
- 1 Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University , Yangling, China .,2 Department of Swine Infectious Disease, Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Qiong Meng
- 2 Department of Swine Infectious Disease, Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Yongguang Wu
- 2 Department of Swine Infectious Disease, Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Zhongze Wang
- 2 Department of Swine Infectious Disease, Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Yewen Zuo
- 2 Department of Swine Infectious Disease, Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Wu Tong
- 2 Department of Swine Infectious Disease, Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Shanghai, China .,3 Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses , Yangzhou, China
| | - Hao Zheng
- 2 Department of Swine Infectious Disease, Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Shanghai, China .,3 Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses , Yangzhou, China
| | - Guoxin Li
- 2 Department of Swine Infectious Disease, Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Shanghai, China .,3 Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses , Yangzhou, China
| | - Shen Yang
- 2 Department of Swine Infectious Disease, Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Shanghai, China .,3 Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses , Yangzhou, China
| | - Hai Yu
- 2 Department of Swine Infectious Disease, Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Shanghai, China .,3 Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses , Yangzhou, China
| | - Tongling Shan
- 2 Department of Swine Infectious Disease, Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Shanghai, China .,3 Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses , Yangzhou, China
| | - En-Min Zhou
- 1 Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University , Yangling, China
| | - Guangzhi Tong
- 2 Department of Swine Infectious Disease, Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences, Shanghai, China .,3 Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses , Yangzhou, China
| |
Collapse
|
23
|
Mahauad-Fernandez WD, Okeoma CM. BST-2: at the crossroads of viral pathogenesis and oncogenesis. Future Virol 2016. [DOI: 10.2217/fvl.15.113] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BST-2 is a moonlight protein with several protective and deleterious functions. Regulation of virus restriction and tumor aggressiveness are the most studied aspects of BST-2 function and thus, the main focus of this perspective. Virus inhibition roles of BST-2 have therapeutic potential that, if properly harnessed, could result in near broad spectrum antiviral. However, the involvement of BST-2 in cancer calls for additional studies on BST-2 biology and re-evaluation of the overall role of BST-2 in host protection, as it appears that BST-2 has pleiotropic effects in the host. Here, we analyze the antiviral and protumor roles of BST-2. We also discuss potential therapeutic options for BST-2 against viral infection and cancer.
Collapse
Affiliation(s)
- Wadie D Mahauad-Fernandez
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Program in Molecular & Cellular Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Chioma M Okeoma
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Program in Molecular & Cellular Biology, University of Iowa, Iowa City, IA 52242, USA
| |
Collapse
|
24
|
Pharmacologic Inhibition of Nedd8 Activation Enzyme Exposes CD4-Induced Epitopes within Env on Cells Expressing HIV-1. J Virol 2015; 90:2486-502. [PMID: 26676780 DOI: 10.1128/jvi.02736-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 12/09/2015] [Indexed: 01/17/2023] Open
Abstract
UNLABELLED HIV-1 Vpu decreases the exposure of epitopes within the viral envelope glycoprotein (Env) on the surface of infected cells by downregulating both BST2 and CD4. To test the hypothesis that inhibiting Vpu activity would increase the exposure of these epitopes and sensitize infected cells to antibody-dependent cellular cytotoxicity (ADCC), we treated cells with the Nedd8 activation enzyme (NAE) inhibitor MLN4924, which inhibits the cullin1-based ubiquitin ligase complex coopted by Vpu to degrade cellular targets. Treatment of HeLa cells with MLN4924 or expression of a dominant negative mutant of cullin1 inhibited the Vpu-mediated downregulation of CD4 but not the downregulation of BST2. NAE inhibition also increased the surface exposure of CD4-induced epitopes within Env on HEK293 cells containing an inducible HIV genome, on infected CEM T cells, and on infected primary T cells. In contrast, the Vpu-mediated downregulation of BST2 was substantially inhibited by MLN4924 only when T cells were treated with alpha interferon (IFN-α) to induce high levels of BST2 expression. As reported previously, the absence of vpu or nef and even more so the combined absence of these two genes sensitized infected cells to ADCC. However, NAE inhibition affected ADCC minimally. Paradoxically, even in infected, IFN-treated cells in which NAE inhibition substantially rescued the surface level of BST2, the surface level of Env detected with an antibody recognizing a CD4-independent epitope (2G12) was minimally increased. Mutation of the C-terminal Vpu residue W76, which supports the ability of Vpu to stimulate virion release by displacing BST2 from assembly sites on the plasma membrane by a cullin1-independent mechanism, increased the exposure of Env detected by 2G12 on infected T cells. Thus, inhibiting the displacement function of Vpu together with its ability to degrade CD4 and BST2 may be required to sensitize infected cells to ADCC. IMPORTANCE Pathogenic viruses encode gene products that enable evasion of host immune surveillance mechanisms. One such mechanism is antibody-dependent cellular cytotoxicity (ADCC), whereby host antibodies bind envelope glycoproteins of the virus that are inserted into the cellular membrane and direct the destruction of infected cells. Targeting pharmacologically the activity of HIV-1 Vpu, which contributes to evasion of ADCC, could potentially sensitize infected cells to this immune surveillance mechanism, an outcome that would have therapeutic implications with respect to the goal of curing HIV-1 infection. The Nedd8 activation enzyme inhibitor MLN4924 blocks the activity of the host ubiquitin ligase that Vpu coopts to direct the degradation of CD4 and BST2. We observed that while MLN4924 partially reverses the activity of Vpu and could become part of a therapeutic approach by virtue of CD4-induced epitope exposure, sufficient Vpu activity as an antagonist of BST2 persists despite this drug to allow escape from ADCC.
Collapse
|
25
|
Mahauad-Fernandez WD, Okeoma CM. The role of BST-2/Tetherin in host protection and disease manifestation. IMMUNITY INFLAMMATION AND DISEASE 2015; 4:4-23. [PMID: 27042298 PMCID: PMC4768070 DOI: 10.1002/iid3.92] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/07/2015] [Accepted: 11/09/2015] [Indexed: 12/21/2022]
Abstract
Host cells respond to viral infections by activating immune response genes that are not only involved in inflammation, but may also predispose cells to cancerous transformation. One such gene is BST‐2, a type II transmembrane protein with a unique topology that endows it tethering and signaling potential. Through this ability to tether and signal, BST‐2 regulates host response to viral infection either by inhibiting release of nascent viral particles or in some models inhibiting viral dissemination. However, despite its antiviral functions, BST‐2 is involved in disease manifestation, a function linked to the ability of BST‐2 to promote cell‐to‐cell interaction. Therefore, modulating BST‐2 expression and/or activity has the potential to influence course of disease.
Collapse
Affiliation(s)
- Wadie D Mahauad-Fernandez
- Department of MicrobiologyCarver College of MedicineUniversity of IowaIowa CityIA52242USA; Interdisciplinary Program in Molecular and Cellular BiologyUniversity of IowaIowa CityIA52242USA
| | - Chioma M Okeoma
- Department of MicrobiologyCarver College of MedicineUniversity of IowaIowa CityIA52242USA; Interdisciplinary Program in Molecular and Cellular BiologyUniversity of IowaIowa CityIA52242USA
| |
Collapse
|
26
|
Three-Dimensional Structural Characterization of HIV-1 Tethered to Human Cells. J Virol 2015; 90:1507-21. [PMID: 26582000 DOI: 10.1128/jvi.01880-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 11/14/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Tetherin (BST2, CD317, or HM1.24) is a host cellular restriction factor that prevents the release of enveloped viruses by mechanically linking virions to the plasma membrane. The precise arrangement of tetherin molecules at the plasma membrane site of HIV-1 assembly, budding, and restriction is not well understood. To gain insight into the biophysical mechanism underlying tetherin-mediated restriction of HIV-1, we utilized cryo-electron tomography (cryo-ET) to directly visualize HIV-1 virus-like particles (VLPs) and virions tethered to human cells in three dimensions (3D). Rod-like densities that we refer to as tethers were seen connecting HIV-1 virions to each other and to the plasma membrane. Native immunogold labeling showed tetherin molecules located on HIV-1 VLPs and virions in positions similar to those of the densities observed by cryo-ET. The location of the tethers with respect to the ordered immature Gag lattice or mature conical core was random. However, tethers were not uniformly distributed on the viral membrane but rather formed clusters at sites of contact with the cell or other virions. Chains of tethered HIV-1 virions often were arranged in a linear fashion, primarily as single chains and, to a lesser degree, as branched chains. Distance measurements support the extended tetherin model, in which the coiled-coil ectodomains are oriented perpendicular with respect to the viral and plasma membranes. IMPORTANCE Tetherin is a cellular factor that restricts HIV-1 release by directly cross-linking the virus to the host cell plasma membrane. We used cryo-electron tomography to visualize HIV-1 tethered to human cells in 3D. We determined that tetherin-restricted HIV-1 virions were physically connected to each other or to the plasma membrane by filamentous tethers that resembled rods ∼15 nm in length, which is consistent with the extended tetherin model. In addition, we found the position of the tethers to be arbitrary relative to the ordered immature Gag lattice or the mature conical cores. However, when present as multiple copies, the tethers clustered at the interface between virions. Tethered HIV-1 virions were arranged in a linear fashion, with the majority as single chains. This study advances our understanding of tetherin-mediated HIV-1 restriction by defining the spatial arrangement and orientation of tetherin molecules at sites of HIV-1 restriction.
Collapse
|
27
|
Mussil B, Javed A, Töpfer K, Sauermann U, Sopper S. Increased BST2 expression during simian immunodeficiency virus infection is not a determinant of disease progression in rhesus monkeys. Retrovirology 2015; 12:92. [PMID: 26554913 PMCID: PMC4641394 DOI: 10.1186/s12977-015-0219-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 10/23/2015] [Indexed: 12/21/2022] Open
Abstract
Background Bone marrow stromal cell antigen 2 (BST2), also known as tetherin, HM1.24 or CD317 represents a type 2 integral membrane protein, which has been described to restrict the production of some enveloped viruses by inhibiting the virus release from the cell surface. This innate antiviral mechanism is counteracted by the HIV-1 viral factor Vpu, targeting BST2 for cellular degradation. Since antiviral BST2 activity has been mainly confirmed by in vitro data, we investigated its role in vivo on the disease progression using the SIV/macaque model for AIDS. We determined BST2 expression in PBMC and leukocyte subsets of uninfected and SIV-infected rhesus macaques by real-time PCR and flow cytometry and correlated it with disease progression and viral load. Results Compared to pre-infection levels, we found increased BST2 expression in PBMC, purified CD4+ lymphocytes and CD14+ monocytes of SIV-infected animals, which correlated with viral load. Highest BST2 levels were found in progressors and lowest levels comparable to uninfected macaques were observed in long-term non-progressors (LTNPs). During acute viremia, BST2 mRNA increased in parallel with MX1, a prototype interferon-stimulated gene. This association was maintained during the whole disease course. Conclusion The detected relationship between BST2 expression and viral load as well as with MX1 indicate a common regulation by the interferon response and suggest rather limited influence of BST2 in vivo on the disease outcome. Electronic supplementary material The online version of this article (doi:10.1186/s12977-015-0219-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Bianka Mussil
- Unit of Infection Models, German Primate Centre, Goettingen, Germany.
| | - Aneela Javed
- Unit of Infection Models, German Primate Centre, Goettingen, Germany. .,Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Science and Technology (NUST), H12, Islamabad, Pakistan.
| | - Katharina Töpfer
- Unit of Infection Models, German Primate Centre, Goettingen, Germany.
| | - Ulrike Sauermann
- Unit of Infection Models, German Primate Centre, Goettingen, Germany.
| | - Sieghart Sopper
- Department of Hematology and Oncology, Medical University Innsbruck, ZVG 7G5 009A, Anichstr. 35, 6020, Innsbruck, Austria. .,Tyrolean Cancer Research Institute, Innsbruck, Austria.
| |
Collapse
|
28
|
El-Sherbiny YM, Holmes TD, Wetherill LF, Black EVI, Wilson EB, Phillips SL, Scott GB, Adair RA, Dave R, Scott KJ, Morgan RSM, Coffey M, Toogood GJ, Melcher AA, Cook GP. Controlled infection with a therapeutic virus defines the activation kinetics of human natural killer cells in vivo. Clin Exp Immunol 2015; 180:98-107. [PMID: 25469725 DOI: 10.1111/cei.12562] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2014] [Indexed: 12/13/2022] Open
Abstract
Human natural killer (NK) cells play an important role in anti-viral immunity. However, studying their activation kinetics during infection is highly problematic. A clinical trial of a therapeutic virus provided an opportunity to study human NK cell activation in vivo in a controlled manner. Ten colorectal cancer patients with liver metastases received between one and five doses of oncolytic reovirus prior to surgical resection of their tumour. NK cell surface expression of the interferon-inducible molecules CD69 and tetherin peaked 24-48 h post-infection, coincident with a peak of interferon-induced gene expression. The interferon response and NK cell activation were transient, declining by 96 h post-infection. Furthermore, neither NK cell activation nor the interferon response were sustained in patients undergoing multiple rounds of virus treatment. These results show that reovirus modulates human NK cell activity in vivo and suggest that this may contribute to any therapeutic effect of this oncolytic virus. Detection of a single, transient peak of activation, despite multiple treatment rounds, has implications for the design of reovirus-based therapy. Furthermore, our results suggest the existence of a post-infection refractory period when the interferon response and NK cell activation are blunted. This refractory period has been observed previously in animal models and may underlie the enhanced susceptibility to secondary infections that is seen following viral infection.
Collapse
Affiliation(s)
- Y M El-Sherbiny
- Leeds Institute of Cancer and Pathology, University of Leeds School of Medicine, St James's University Hospital, Leeds, UK; Affiliated with the Clinical Pathology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Yamada E, Yoshikawa R, Nakano Y, Misawa N, Koyanagi Y, Sato K. Impacts of humanized mouse models on the investigation of HIV-1 infection: illuminating the roles of viral accessory proteins in vivo. Viruses 2015; 7:1373-90. [PMID: 25807049 PMCID: PMC4379576 DOI: 10.3390/v7031373] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/10/2015] [Accepted: 03/10/2015] [Indexed: 12/26/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) encodes four accessory genes: vif, vpu, vpr, and nef. Recent investigations using in vitro cell culture systems have shed light on the roles of these HIV-1 accessory proteins, Vif, Vpr, Vpu, and Nef, in counteracting, modulating, and evading various cellular factors that are responsible for anti-HIV-1 intrinsic immunity. However, since humans are the exclusive target for HIV-1 infection, conventional animal models are incapable of mimicking the dynamics of HIV-1 infection in vivo. Moreover, the effects of HIV-1 accessory proteins on viral infection in vivo remain unclear. To elucidate the roles of HIV-1 accessory proteins in the dynamics of viral infection in vivo, humanized mouse models, in which the mice are xenotransplanted with human hematopoietic stem cells, has been utilized. This review describes the current knowledge of the roles of HIV-1 accessory proteins in viral infection, replication, and pathogenicity in vivo, which are revealed by the studies using humanized mouse models.
Collapse
Affiliation(s)
- Eri Yamada
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Rokusuke Yoshikawa
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Yusuke Nakano
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Naoko Misawa
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Yoshio Koyanagi
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
| | - Kei Sato
- Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto 6068507, Japan.
- CREST, Japan Science and Technology Agency, Saitama 3220012, Japan.
| |
Collapse
|
30
|
Karrich JJ, Jachimowski LCM, Uittenbogaart CH, Blom B. The plasmacytoid dendritic cell as the Swiss army knife of the immune system: molecular regulation of its multifaceted functions. THE JOURNAL OF IMMUNOLOGY 2015; 193:5772-8. [PMID: 25480956 DOI: 10.4049/jimmunol.1401541] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Plasmacytoid dendritic cells (pDC) have been regarded as the "professional type I IFN-producing cells" of the immune system following viral recognition that relies on the expression of TLR7 and TLR9. Furthermore, pDC link the innate and adaptive immune systems via cytokine production and Ag presentation. More recently, their ability to induce tolerance and cytotoxicity has been added to their "immune skills." Such a broad range of actions, resembling the diverse functional features of a Swiss army knife, requires strong and prompt molecular regulation to prevent detrimental effects, including autoimmune pathogenesis or tumor escape. Over the last decades, we and other investigators have started to unravel some aspects of the signaling pathways that regulate the various functions of human pDC. In this article, we review aspects of the molecular regulatory mechanisms to control pDC function in light of their multifaceted roles during immunity, autoimmunity, and cancer.
Collapse
Affiliation(s)
- Julien J Karrich
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Loes C M Jachimowski
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Christel H Uittenbogaart
- Department of Pediatrics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095; and Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095
| | - Bianca Blom
- Department of Cell Biology and Histology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands;
| |
Collapse
|
31
|
Lewinski MK, Jafari M, Zhang H, Opella SJ, Guatelli J. Membrane Anchoring by a C-terminal Tryptophan Enables HIV-1 Vpu to Displace Bone Marrow Stromal Antigen 2 (BST2) from Sites of Viral Assembly. J Biol Chem 2015; 290:10919-33. [PMID: 25759385 DOI: 10.1074/jbc.m114.630095] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Indexed: 12/28/2022] Open
Abstract
The restriction factor BST2 (tetherin) prevents the release of enveloped viruses from the host cell and is counteracted by HIV-1 Vpu. Vpu and BST2 interact directly via their transmembrane domains. This interaction enables Vpu to induce the surface down-regulation and the degradation of BST2, but neither of these activities fully accounts for the ability of Vpu to enhance virion release. During a study of naturally occurring Vpu proteins, we found that a tryptophan residue near the Vpu C terminus is particularly important for enhancing virion release. Vpu proteins with a W76G polymorphism degraded and down-regulated BST2 from the cell surface, yet they inefficiently stimulated virion release. Here we explore the mechanism of this anomaly. We find that Trp-76 is critical for the ability of Vpu to displace BST2 from sites of viral assembly in the plane of the plasma membrane. This effect does not appear to involve a general reorganization of the membrane microdomains associated with virion assembly, but rather is a specific effect of Vpu on BST2. Using NMR spectroscopy, we find that the cytoplasmic domain of Vpu and Trp-76 specifically interact with lipids. Moreover, paramagnetic relaxation enhancement studies show that Trp-76 inserts into the lipid. These data are consistent with a model whereby Trp-76 anchors the C terminus of the cytoplasmic tail of Vpu to the plasma membrane, enabling the movement of Vpu-bound BST2 away from viral assembly sites.
Collapse
Affiliation(s)
- Mary K Lewinski
- From the Departments of Medicine and the Veterans Affairs San Diego Healthcare System, San Diego, California 92161
| | | | - Hua Zhang
- Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0679 and
| | - Stanley J Opella
- Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0679 and
| | - John Guatelli
- From the Departments of Medicine and the Veterans Affairs San Diego Healthcare System, San Diego, California 92161
| |
Collapse
|
32
|
Sauter D. Counteraction of the multifunctional restriction factor tetherin. Front Microbiol 2014; 5:163. [PMID: 24782851 PMCID: PMC3989765 DOI: 10.3389/fmicb.2014.00163] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 03/26/2014] [Indexed: 01/28/2023] Open
Abstract
The interferon-inducible restriction factor tetherin (also known as CD317, BST-2 or HM1.24) has emerged as a key component of the antiviral immune response. Initially, tetherin was shown to restrict replication of various enveloped viruses by inhibiting the release of budding virions from infected cells. More recently, it has become clear that tetherin also acts as a pattern recognition receptor inducing NF-κB-dependent proinflammatory gene expression in virus infected cells. Whereas the ability to restrict virion release is highly conserved among mammalian tetherin orthologs and thus probably an ancient function of this protein, innate sensing seems to be an evolutionarily recent activity. The potent and broad antiviral activity of tetherin is reflected by the fact that many viruses evolved means to counteract this restriction factor. A continuous arms race with viruses has apparently driven the evolution of different isoforms of tetherin with different functional properties. Interestingly, tetherin has also been implicated in cellular processes that are unrelated to immunity, such as the organization of the apical actin network and membrane microdomains or stabilization of the Golgi apparatus. In this review, I summarize our current knowledge of the different functions of tetherin and describe the molecular strategies that viruses have evolved to antagonize or evade this multifunctional host restriction factor.
Collapse
Affiliation(s)
- Daniel Sauter
- Institute of Molecular Virology, Ulm University Medical Center Ulm, Germany
| |
Collapse
|
33
|
HIV-1 Vpu antagonism of tetherin inhibits antibody-dependent cellular cytotoxic responses by natural killer cells. J Virol 2014; 88:6031-46. [PMID: 24623433 DOI: 10.1128/jvi.00449-14] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
UNLABELLED The type I interferon-inducible factor tetherin retains virus particles on the surfaces of cells infected with vpu-deficient human immunodeficiency virus type 1 (HIV-1). While this mechanism inhibits cell-free viral spread, the immunological implications of tethered virus have not been investigated. We found that surface tetherin expression increased the antibody opsonization of vpu-deficient HIV-infected cells. The absence of Vpu also stimulated NK cell-activating FcγRIIIa signaling and enhanced NK cell degranulation and NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC). The deletion of vpu in HIV-1-infected primary CD4(+) T cells enhanced the levels of antibody binding and Fc receptor signaling mediated by HIV-positive-patient-derived antibodies. The magnitudes of antibody binding and Fc signaling were both highly correlated to the levels of tetherin on the surfaces of infected primary CD4 T cells. The affinity of antibody binding to FcγRIIIa was also found to be critical in mediating efficient Fc activation. These studies implicate Vpu antagonism of tetherin as an ADCC evasion mechanism that prevents antibody-mediated clearance of virally infected cells. IMPORTANCE The ability of the HIV-1 accessory factor to antagonize tetherin has been considered to primarily function by limiting the spread of virus by preventing the release of cell-free virus. This study supports the hypothesis that a major function of Vpu is to decrease the recognition of infected cells by anti-HIV antibodies at the cell surface, thereby reducing recognition by antibody-dependent clearance by natural killer cells.
Collapse
|
34
|
Activities of transmitted/founder and chronic clade B HIV-1 Vpu and a C-terminal polymorphism specifically affecting virion release. J Virol 2014; 88:5062-78. [PMID: 24574397 DOI: 10.1128/jvi.03472-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED Acute HIV-1 infection is characterized by a type I interferon response, resulting in the induction of host restriction factors. HIV-1 has evolved to counteract these factors, and one such adaptation, the ability of Vpu to counteract BST2/tetherin, is associated with the evolution of simian immunodeficiency virus (SIVcpz) into pandemic group M human immunodeficiency virus type 1 (HIV-1). During transmission between individuals, very few viruses or even a single virus, the "transmitted/founder" (T/F) virus, gives rise to the new infection, but in the new host the selective pressure of the immune response yields the diverse "quasispecies" of chronic infection. Here we examine the functional characteristics of Vpu proteins encoded by T/F viruses compared to acute and chronic viruses from longitudinally sampled subjects. The studied T/F Vpu proteins showed a trend toward optimized CD4 downregulation compared to chronic Vpu proteins but did not differ substantially in their ability to downregulate BST2 or enhance virion release, although individual clones from each group were impaired in these activities. Analysis of the functionally impaired clones identified a C-terminal residue, W76, as important specifically for Vpu enhancement of virion release. Primary Vpu clones encoding a W76G polymorphism, or site-directed mutants encoding a W76G substitution, were impaired in their ability to enhance virion release, but they were not defective for BST2 surface downregulation. Conversely, the virion release function of impaired primary clones was restored by creating a G76W substitution. The identification of W76 as important for virion release enhancement that is independent of BST2 surface downregulation supports the potential to mechanistically separate these functions of Vpu. IMPORTANCE To establish infection in a host, HIV-1 must evade the host's immune response, including the production of antiviral factors. HIV-1 encodes proteins that antagonize these defenses, including Vpu. Vpu counteracts the host protein BST2, which blocks the release of progeny viruses from the host cell. To determine the importance of Vpu activity to HIV-1 transmission, this study assessed the functionality of Vpu from viruses isolated soon after transmission ("transmitted/founder" viruses) compared to isolates from chronic infection. Although the anti-BST2 activity of Vpu proteins from the tested transmitted/founder viruses did not differ from the activity of the chronic Vpu proteins, the transmitted/founder Vpu proteins trended toward having superior activity against another host protein, CD4. Further, this study identified an amino acid near the C terminus of Vpu that is specifically important for Vpu's ability to enhance the release of progeny virus from the host cell, supporting the notion of a new mechanism for this function of Vpu.
Collapse
|
35
|
Pickering S, Hué S, Kim EY, Reddy S, Wolinsky SM, Neil SJD. Preservation of tetherin and CD4 counter-activities in circulating Vpu alleles despite extensive sequence variation within HIV-1 infected individuals. PLoS Pathog 2014; 10:e1003895. [PMID: 24465210 PMCID: PMC3900648 DOI: 10.1371/journal.ppat.1003895] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 12/06/2013] [Indexed: 01/19/2023] Open
Abstract
The HIV-1 Vpu protein is expressed from a bi-cistronic message late in the viral life cycle. It functions during viral assembly to maximise infectious virus release by targeting CD4 for proteosomal degradation and counteracting the antiviral protein tetherin (BST2/CD317). Single genome analysis of vpu repertoires throughout infection in 14 individuals infected with HIV-1 clade B revealed extensive amino acid diversity of the Vpu protein. For the most part, this variation in Vpu increases over the course of infection and is associated with predicted epitopes of the individual's MHC class I haplotype, suggesting CD8+ T cell pressure is the major driver of Vpu sequence diversity within the host. Despite this variability, the Vpu functions of targeting CD4 and counteracting both physical virus restriction and NF-κB activation by tetherin are rigorously maintained throughout HIV-1 infection. Only a minority of circulating alleles bear lesions in either of these activities at any given time, suggesting functional Vpu mutants are heavily selected against even at later stages of infection. Comparison of Vpu proteins defective for one or several functions reveals novel determinants of CD4 downregulation, counteraction of tetherin restriction, and inhibition of NF-κB signalling. These data affirm the importance of Vpu functions for in vivo persistence of HIV-1 within infected individuals, not simply for transmission, and highlight its potential as a target for antiviral therapy. The accessory protein Vpu, encoded by HIV-1, performs at least two major roles in the virus life cycle, namely the degradation of newly synthesized CD4 molecules and the counteraction of a host antiviral protein, tetherin. These activities promote the release of infectious viruses from host cells, and recent evidence suggests that Vpu function has been crucial for the cross-species transmission of HIV-1 from chimpanzees, and its subsequent pandemic spread in humans. Here we studied the functional variation in Vpu in infected individuals. We found that the Vpu amino acid sequence can be highly variable within an individual, and that this variation is likely to result from host immune responses targeting antigens derived from Vpu. However, despite this variation, Vpu's major functions are preserved, with only a minority of circulating alleles showing defects throughout the course of infection. These data suggest that defective Vpu proteins are selected against within the infected individual, implying that Vpu functions are critical for HIV-1 replication throughout natural infection, not simply at transmission. Therefore Vpu may represent a novel target for antiviral therapy to augment current treatment strategies for HIV/AIDS.
Collapse
Affiliation(s)
- Suzanne Pickering
- Department of Infectious Disease, King's College School of Medicine, Guy's Hospital, London, United Kingdom
| | - Stephane Hué
- MRC Centre for Medical Molecular Virology, University College London, London, United Kingdom
| | - Eun-Young Kim
- Department of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Susheel Reddy
- Department of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Steven M. Wolinsky
- Department of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Stuart J. D. Neil
- Department of Infectious Disease, King's College School of Medicine, Guy's Hospital, London, United Kingdom
- * E-mail:
| |
Collapse
|
36
|
Rahmberg AR, Neidermyer WJ, Breed MW, Alvarez X, Midkiff CC, Piatak M, Lifson JD, Evans DT. Tetherin upregulation in simian immunodeficiency virus-infected macaques. J Virol 2013; 87:13917-21. [PMID: 24109219 PMCID: PMC3838227 DOI: 10.1128/jvi.01757-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 10/02/2013] [Indexed: 11/20/2022] Open
Abstract
Here we show that simian immunodeficiency virus (SIV) infection of rhesus macaques results in rapid upregulation of tetherin (BST-2 or CD317) on peripheral blood lymphocytes, including the CD4(+) CCR5(+) T cell targets of virus infection, with a peak of induction that coincides with peak alpha interferon (IFN-α) levels in plasma, and that tetherin remains above baseline levels throughout chronic infection. These observations are consistent with a role for tetherin in innate immunity to immunodeficiency virus infection.
Collapse
Affiliation(s)
- Andrew R. Rahmberg
- Department of Microbiology and Immunobiology, Harvard Medical School, New England Primate Research Center, Southborough, Massachusetts, USA
| | - William J. Neidermyer
- Department of Microbiology and Immunobiology, Harvard Medical School, New England Primate Research Center, Southborough, Massachusetts, USA
| | - Matthew W. Breed
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, Louisiana, USA
| | - Xavier Alvarez
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, Louisiana, USA
| | - Cecily C. Midkiff
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, Louisiana, USA
| | - Michael Piatak
- SAIC—Frederick, National Cancer Institute at Frederick, Frederick, Maryland, USA
| | - Jeffrey D. Lifson
- SAIC—Frederick, National Cancer Institute at Frederick, Frederick, Maryland, USA
| | - David T. Evans
- Department of Microbiology and Immunobiology, Harvard Medical School, New England Primate Research Center, Southborough, Massachusetts, USA
| |
Collapse
|
37
|
Santa-Marta M, de Brito PM, Godinho-Santos A, Goncalves J. Host Factors and HIV-1 Replication: Clinical Evidence and Potential Therapeutic Approaches. Front Immunol 2013; 4:343. [PMID: 24167505 PMCID: PMC3807056 DOI: 10.3389/fimmu.2013.00343] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 10/06/2013] [Indexed: 12/17/2022] Open
Abstract
HIV and human defense mechanisms have co-evolved to counteract each other. In the process of infection, HIV takes advantage of cellular machinery and blocks the action of the host restriction factors (RF). A small subset of HIV+ individuals control HIV infection and progression to AIDS in the absence of treatment. These individuals known as long-term non-progressors (LNTPs) exhibit genetic and immunological characteristics that confer upon them an efficient resistance to infection and/or disease progression. The identification of some of these host factors led to the development of therapeutic approaches that attempted to mimic the natural control of HIV infection. Some of these approaches are currently being tested in clinical trials. While there are many genes which carry mutations and polymorphisms associated with non-progression, this review will be specifically focused on HIV host RF including both the main chemokine receptors and chemokines as well as intracellular RF including, APOBEC, TRIM, tetherin, and SAMHD1. The understanding of molecular profiles and mechanisms present in LTNPs should provide new insights to control HIV infection and contribute to the development of novel therapies against AIDS.
Collapse
Affiliation(s)
- Mariana Santa-Marta
- URIA-Centro de Patogénese Molecular, Faculdade de Farmácia, Universidade de Lisboa , Lisboa , Portugal ; Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa , Lisboa , Portugal
| | | | | | | |
Collapse
|
38
|
Generation of rhesus macaque-tropic HIV-1 clones that are resistant to major anti-HIV-1 restriction factors. J Virol 2013; 87:11447-61. [PMID: 23966385 DOI: 10.1128/jvi.01549-13] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) replication in macaque cells is restricted mainly by antiviral cellular APOBEC3, TRIM5α/TRIM5CypA, and tetherin proteins. For basic and clinical HIV-1/AIDS studies, efforts to construct macaque-tropic HIV-1 (HIV-1mt) have been made by us and others. Although rhesus macaques are commonly and successfully used as infection models, no HIV-1 derivatives suitable for in vivo rhesus research are available to date. In this study, to obtain novel HIV-1mt clones that are resistant to major restriction factors, we altered Gag and Vpu of our best HIV-1mt clone described previously. First, by sequence- and structure-guided mutagenesis, three amino acid residues in Gag-capsid (CA) (M94L/R98S/G114Q) were found to be responsible for viral growth enhancement in a macaque cell line. Results of in vitro TRIM5α susceptibility testing of HIV-1mt carrying these substitutions correlated well with the increased viral replication potential in macaque peripheral blood mononuclear cells (PBMCs) with different TRIM5 alleles, suggesting that the three amino acids in HIV-1mt CA are involved in the interaction with TRIM5α. Second, we replaced the transmembrane domain of Vpu of this clone with the corresponding region of simian immunodeficiency virus SIVgsn166 Vpu. The resultant clone, MN4/LSDQgtu, was able to antagonize macaque but not human tetherin, and its Vpu effectively functioned during viral replication in a macaque cell line. Notably, MN4/LSDQgtu grew comparably to SIVmac239 and much better than any of our other HIV-1mt clones in rhesus macaque PBMCs. In sum, MN4/LSDQgtu is the first HIV-1 derivative that exhibits resistance to the major restriction factors in rhesus macaque cells.
Collapse
|
39
|
Raposo RAS, Abdel-Mohsen M, Holditch SJ, Kuebler PJ, Cheng RG, Eriksson EM, Liao W, Pillai SK, Nixon DF. Increased expression of intrinsic antiviral genes in HLA-B*57-positive individuals. J Leukoc Biol 2013; 94:1051-9. [PMID: 23929683 DOI: 10.1189/jlb.0313150] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The genetic background of HIV-1-infected subjects, particularly the HLA class I haplotype, appears to be critical in determining disease progression rates, thought to be a result of the role of HIV-1-specific CD8(+) T cell responses. The HLA-B*57 allele is strongly associated with viremic suppression and slower disease progression. However, there is considerable heterogeneity in HIV-1 disease progression rates among HLA-B*57-positive subjects, suggesting that additional factors may help to contain viral replication. In this report, we investigated the association between host restriction factors, other established immunological parameters, and HLA type in HIV-1-seronegative individuals. Our results demonstrate that healthy, uninfected HLA-B*57-positive individuals exhibit significantly higher gene-expression levels of host restriction factors, such as APOBEC3A, APOBEC3B, BST-2/tetherin, and ISG15. Interestingly, HLA-B*57 individuals have significantly lower CD4(+) T cell frequencies but harbor slightly more activated CD4(+) T cells compared with their HLA-B*35 counterparts. We detected significant correlations between CD4(+) T cell activation and expression of several APOBEC3 family members, BST-2/tetherin, SAMHD1, and TRIM5α in HLA-B*57-positive individuals. To our knowledge, this is the first report showing distinct associations between host restriction factors and HLA class I genotype. Our results provide insights into natural protection mechanisms and immunity against HIV-1 that fall outside of classical HLA-mediated effects.
Collapse
Affiliation(s)
- Rui André Saraiva Raposo
- 2.Division of Experimental Medicine, 1001 Potrero Ave., Bldg. 3, Room 603, Box 1234, San Francisco, CA 94110, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Jones PH, Mahauad-Fernandez WD, Madison MN, Okeoma CM. BST-2/tetherin is overexpressed in mammary gland and tumor tissues in MMTV-induced mammary cancer. Virology 2013; 444:124-39. [PMID: 23806386 DOI: 10.1016/j.virol.2013.05.042] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/03/2013] [Accepted: 05/31/2013] [Indexed: 11/26/2022]
Abstract
BST-2 restricts MMTV replication, but once infection has established, MMTV modulates BST-2 levels. MMTV-directed BST-2 modulation is tissue-specific and dependent on infection and neoplastic transformation status of cells. In the lymphoid compartment of infected mice, BST-2 expression is first upregulated and then significantly downregulated regardless of absence or presence of mammary tumors. However, in mammary gland tissues, upregulation of BST-2 expression is dependent on the presence of mammary tumors and tumor tissues themselves have high BST-2 levels. Elevated BST-2 expression in these tissues is not attributable to IFN since levels of IFNα and IFNγ negatively correlate with BST-2. Importantly, soluble factors released by tumor cells suppress IFNα and IFNγ but induce BST-2. These data suggest that overexpression of BST-2 in carcinoma tissues could not be attributed to IFNs but to a yet to be determined factor that upregulates BST-2 once oncogenesis is initiated.
Collapse
Affiliation(s)
- Philip H Jones
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA.
| | | | | | | |
Collapse
|
41
|
Tavano B, Galao RP, Graham DR, Neil SJD, Aquino VN, Fuchs D, Boasso A. Ig-like transcript 7, but not bone marrow stromal cell antigen 2 (also known as HM1.24, tetherin, or CD317), modulates plasmacytoid dendritic cell function in primary human blood leukocytes. THE JOURNAL OF IMMUNOLOGY 2013; 190:2622-30. [PMID: 23401591 DOI: 10.4049/jimmunol.1202391] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The Ig-like transcript (ILT) 7 is a surface molecule selectively expressed by human plasmacytoid dendritic cells (pDCs). ILT7 cross-linking suppresses pDC activation and type I IFN (IFN-I) secretion following TLR7/9 engagement. The bone marrow stromal cell Ag 2 (BST2, aka HM1.24, tetherin, or CD317) is expressed by different cell types upon exposure to IFN-I and is a natural ligand for ILT7. In this study, we show that ILT7 expression decreased spontaneously in pDCs upon in vitro culture, which correlates with pDC differentiation measured as increased side scatter properties and CCR7 expression. TLR7/9 ligands, as well as HIV, induced BST2 upregulation on all tested cell types except T cells, which required TCR stimulation to respond to TLR9L-induced IFN-I. IFN-γ, IL-4, IL-10, and TNF-α had only marginal effects on BST2 expression in blood leukocytes compared with TLR9L. Preincubation with ILT7 cross-linking Ab inhibited IFN-I production in PBMCs treated with TLR7/9L or HIV, whereas BST2 blockade did not affect IFN-I responses even when BST2 upregulation was further boosted with TCR agonists or immunoregulatory cytokines. Our data indicate that BST2-mediated ILT7 cross-linking may act as a homeostatic regulatory mechanism on immature circulating pDC, rather than a negative feedback for activated mature pDCs that have downregulated ILT7.
Collapse
Affiliation(s)
- Barbara Tavano
- Division of Infectious Diseases, Immunology Section, Chelsea and Westminster Hospital, Department of Medicine, Faculty of Medicine, Imperial College, London SW10 9NH, United Kingdom.
| | | | | | | | | | | | | |
Collapse
|
42
|
Blanchet FP, Stalder R, Czubala M, Lehmann M, Rio L, Mangeat B, Piguet V. TLR-4 engagement of dendritic cells confers a BST-2/tetherin-mediated restriction of HIV-1 infection to CD4+ T cells across the virological synapse. Retrovirology 2013; 10:6. [PMID: 23311681 PMCID: PMC3561259 DOI: 10.1186/1742-4690-10-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 12/19/2012] [Indexed: 12/12/2022] Open
Abstract
Background Dendritic cells and their subsets, located at mucosal surfaces, are among the first immune cells to encounter disseminating pathogens. The cellular restriction factor BST-2/tetherin (also known as CD317 or HM1.24) potently restricts HIV-1 release by retaining viral particles at the cell surface in many cell types, including primary cells such as macrophages. However, BST-2/tetherin does not efficiently restrict HIV-1 infection in immature dendritic cells. Results We now report that BST-2/tetherin expression in myeloid (myDC) and monocyte-derived dendritic cells (DC) can be significantly up-regulated by IFN-α treatment and TLR-4 engagement with LPS. In contrast to HeLa or 293T cells, infectious HIV-1 release in immature DC and IFN-α–matured DC was only modestly affected in the absence of Vpu compared to wild-type viruses. Strikingly, immunofluorescence analysis revealed that BST-2/tetherin was excluded from HIV containing tetraspanin-enriched microdomains (TEMs) in both immature DC and IFN-α–matured DC. In contrast, in LPS-mediated mature DC, BST-2/tetherin exerted a significant restriction in transfer of HIV-1 infection to CD4+ T cells. Additionally, LPS, but not IFN-α stimulation of immature DC, leads to a dramatic redistribution of cellular restriction factors to the TEM as well as at the virological synapse between DC and CD4+ T cells. Conclusions In conclusion, we demonstrate that TLR-4 engagement in immature DC significantly up-regulates the intrinsic antiviral activity of BST-2/tetherin, during cis-infection of CD4+ T cells across the DC/T cell virological synapse. Manipulating the function and potency of cellular restriction factors such as BST-2/tetherin to HIV-1 infection, has implications in the design of antiviral therapeutic strategies.
Collapse
Affiliation(s)
- Fabien P Blanchet
- Department of Dermatology and Wound Healing, Institute of Infection and Immunity, Cardiff University School of Medicine, 3rd Floor, Glamorgan house, Heath Park, Wales, Cardiff, CF14 4XN, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
43
|
Abstract
Tetherin (BST2/CD317) has emerged as a key host cell defense molecule, inhibiting the release and spread of diverse enveloped virions from infected cells. In this chapter, I review the molecular and cellular basis for tetherin's antiviral activities and the function of virally encoded countermeasures that disrupt its function. I further describe recent advances in our understanding of tetherin's associated role in viral pattern recognition and the evidence for its role in limiting viral pathogenesis in vivo.
Collapse
Affiliation(s)
- Stuart J D Neil
- Department of Infectious Disease, King's College London School of Medicine, London, UK.
| |
Collapse
|
44
|
Ilinskaya A, Derse D, Hill S, Princler G, Heidecker G. Cell-cell transmission allows human T-lymphotropic virus 1 to circumvent tetherin restriction. Virology 2012; 436:201-9. [PMID: 23260108 DOI: 10.1016/j.virol.2012.11.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 09/19/2012] [Accepted: 11/19/2012] [Indexed: 11/16/2022]
Abstract
Tetherin is part of the cellular innate immunity and impedes cell-free transmission of viruses that bud from the plasma membrane by retaining them on the cell surface. Some viruses have evolved activities in different proteins such as Vpu (HIV-1), K-protein (KSHV), Nef (SIV) or Env (HIV-2) to downregulate tetherin and overcome its restriction. We found that chronically HTLV-1 infected T-cell lines express eightfold more tetherin than uninfected transformed T-cell lines suggesting that tetherin expression is not inhibited by the virus. We observed that even small amounts of exogenous tetherin caused the retention of HTLV-1 on the cell surface and severely reduced cell-free infectivity of HTLV-1, but that cell-cell transmission, which is more relevant for HTLV-1, was significantly less decreased. However, knock-down of tetherin expresssion resulted in a slight increase in cell-cell infection indicating that the protein does not enhance this route of transmission.
Collapse
Affiliation(s)
- Anna Ilinskaya
- HIV-Drug Resistance Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA.
| | | | | | | | | |
Collapse
|
45
|
Guzzo C, Jung M, Graveline A, Banfield BW, Gee K. IL-27 increases BST-2 expression in human monocytes and T cells independently of type I IFN. Sci Rep 2012; 2:974. [PMID: 23240078 PMCID: PMC3521153 DOI: 10.1038/srep00974] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 10/22/2012] [Indexed: 11/16/2022] Open
Abstract
IL-27 modulates inflammatory responses by influencing cytokine secretion and CD4 T cell differentiation. Recently, IL-27 was demonstrated to inhibit HIV replication by inducing type I interferon (IFN) expression and subsequent IFN-dependent expression of apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like (APOBEC)-3 family members, a group of antiviral cytidine deaminases. To characterize other anti-viral genes modulated by IL-27, we examined another IFN-responsive gene: tetherin/bone marrow stromal cell antigen 2 (BST-2). Our study shows that IL-27 can directly induce BST-2 expression, independently of an intermediary type I IFN response. Quantitative RT-PCR analysis demonstrated IL-27-induced BST-2 mRNA expression as early as 2h after exposure of cells to IL-27. In the presence of the type I IFN-neutralizing protein, B18R, IL-27-induced BST-2 expression was maintained, demonstrating that IFN is not an intermediary in IL-27-induced BST-2. Taken together, our findings identify a novel function of IL-27 as a direct stimulator of BST-2 expression.
Collapse
Affiliation(s)
- Christina Guzzo
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston ON, Canada, K7L 3N6
| | - Masany Jung
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston ON, Canada, K7L 3N6
| | - Ashley Graveline
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston ON, Canada, K7L 3N6
| | - Bruce W. Banfield
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston ON, Canada, K7L 3N6
| | - Katrina Gee
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston ON, Canada, K7L 3N6
| |
Collapse
|
46
|
Laplana M, Caruz A, Pineda JA, Puig T, Fibla J. Association of BST-2 Gene Variants With HIV Disease Progression Underscores the Role of BST-2 in HIV Type 1 Infection. J Infect Dis 2012; 207:411-9. [DOI: 10.1093/infdis/jis685] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
47
|
Sato K, Gee P, Koyanagi Y. Vpu and BST2: Still Not There Yet? Front Microbiol 2012; 3:131. [PMID: 22509177 PMCID: PMC3321438 DOI: 10.3389/fmicb.2012.00131] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 03/20/2012] [Indexed: 11/13/2022] Open
Abstract
Extensive investigations have identified two cellular proteins in humans that potently inhibit HIV type 1 (HIV-1) replication and are widely accepted as "restriction factors." APOBEC3G was identified as a restriction factor that diminishes HIV-1 replication by inducing G-to-A hypermutation in the viral genome, while BST2 has been identified as another restriction factor that impairs the release of nascent virions by tethering them on the surface of infected cells. To counter these restriction factors, HIV-1 has equipped itself with its own weapons: viral infectivity factor (Vif) degrades APOBEC3G, while viral protein U (Vpu) antagonizes BST2. These findings have allowed us to further our understanding of virus-host interaction, namely, the interplay between viral factors versus host restriction factors. In the first case, the interplay between APOBEC3G and Vif is clear: vif-deficient HIV-1 is incapable of replicating in APOBEC3G-expressing cells. This insight directly indicates that APOBEC3G is a bona fide restriction factor and has intrinsic immunity against HIV-1, and that Vif is a prerequisite for HIV-1 infection. In other words, the relationship between Vif and APOBEC3G has already "matured," and Vif has highly evolved to overcome APOBEC3G. On the other hand, although BST2 drastically impairs the release of vpu-deficient HIV-1 virions, it is puzzling that vpu-deficient HIV-1 is still able to replicate in BST2-expressing cells. These insights imply that BST2-mediated anti-HIV-1 activity is vulnerable, and that Vpu is dispensable for HIV-1 infection. If so, why has Vpu acquired the counteracting potential against BST2? Was it necessary or important for HIV-1? Or is the relationship between Vpu and BST2 still "immature"? In this review, we particularly focus on the interplay between Vpu and BST2. We discuss the possibility that Vpu has evolved as a potent antagonist against BST2, and finally, propose a hypothesis that Vpu has evolved as a promoter of human-to-human HIV-1 transmission. Since the first report of acquired immunodeficiency syndrome patients in 1981, HIV-1 has spread explosively worldwide and is currently a pandemic. This review proposes a concept suggesting that the current HIV-1 pandemic may be partly attributed by Vpu.
Collapse
Affiliation(s)
- Kei Sato
- Center for Emerging Virus Research, Institute for Virus Research, Kyoto University Sakyo-ku, Kyoto, Japan
| | | | | |
Collapse
|
48
|
Barrett BS, Smith DS, Li SX, Guo K, Hasenkrug KJ, Santiago ML. A single nucleotide polymorphism in tetherin promotes retrovirus restriction in vivo. PLoS Pathog 2012; 8:e1002596. [PMID: 22457621 PMCID: PMC3310811 DOI: 10.1371/journal.ppat.1002596] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 02/01/2012] [Indexed: 01/19/2023] Open
Abstract
Tetherin is a membrane protein of unusual topology expressed from rodents to humans that accumulates enveloped virus particles on the surface of infected cells. However, whether this ‘tethering’ activity promotes or restricts retroviral spread during acute retrovirus infection in vivo is controversial. We report here the identification of a single nucleotide polymorphism in the Tetherin gene of NZW/LacJ (NZW) mice that mutated the canonical ATG start site to GTG. Translation of NZW Tetherin from downstream ATGs deleted a conserved dual-tyrosine endosomal sorting motif, resulting in higher cell surface expression and more potent inhibition of Friend retrovirus release compared to C57BL/6 (B6) Tetherin in vitro. Analysis of (B6×NZW)F1 hybrid mice revealed that increased Tetherin cell surface expression in NZW mice is a recessive trait in vivo. Using a classical genetic backcrossing approach, NZW Tetherin expression strongly correlated with decreased Friend retrovirus replication and pathogenesis. However, the protective effect of NZW Tetherin was not observed in the context of B6 Apobec3/Rfv3 resistance. These findings identify the first functional Tetherin polymorphism within a mammalian host, demonstrate that Tetherin cell surface expression is a key parameter for retroviral restriction, and suggest the existence of a restriction factor hierarchy to counteract pathogenic retrovirus infections in vivo. Significant portions of the human and mouse genomes are comprised of retroviral sequences, revealing the long history of conflict between mammalian hosts and retroviruses that led to the evolution of host restriction factors. Nucleotide mutations in restriction factor genes provide a glimpse of this ongoing evolutionary process, but studies that directly probe the impact of restriction factor mutations during retrovirus infection are limited. In this study, we identified a single nucleotide mutation in the Tetherin host restriction gene that resulted in retention of Tetherin on the cell surface. In cell culture, Tetherin accumulates virions on the infected cell surface and prevents virion release, but some studies suggested that Tetherin might facilitate cell-to-cell virus spread. Our studies reveal that the Tetherin polymorphism inhibits retrovirus replication and disease. Thus, increased Tetherin cell surface expression enhanced the antiretroviral function of Tetherin. These results could have important implications in harnessing the biology of Tetherin for controlling pathogenic retroviruses such as HIV-1.
Collapse
Affiliation(s)
- Bradley S. Barrett
- Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Diana S. Smith
- Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Sam X. Li
- Department of Microbiology, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Kejun Guo
- Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Kim J. Hasenkrug
- Rocky Mountain Laboratories, National Institutes for Allergy and Infectious Diseases, National Institutes of Health (NIH), Hamilton, Montana, United States of America
| | - Mario L. Santiago
- Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
- Department of Microbiology, University of Colorado Denver, Aurora, Colorado, United States of America
- Department of Immunology, University of Colorado Denver, Aurora, Colorado, United States of America
- * E-mail:
| |
Collapse
|
49
|
Virus-activated interferon regulatory factor 7 upregulates expression of the interferon-regulated BST2 gene independently of interferon signaling. J Virol 2012; 86:3513-27. [PMID: 22301143 DOI: 10.1128/jvi.06971-11] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BST-2/tetherin is an interferon (IFN)-inducible host restriction factor that inhibits the release of many enveloped viruses and functions as a negative-feedback regulator of IFN production by plasmacytoid dendritic cells. Currently, mechanisms underlying BST2 transcriptional regulation by type I IFN remain largely unknown. Here, we demonstrate that the BST2 promoter is a secondary target of the IFN cascade and show that a single IRF binding site is sufficient to render this promoter responsive to IFN-α. Interestingly, expression of IRF-1 or virus-activated forms of IRF-3 and IRF-7 stimulated the BST2 promoter even under conditions where type I IFN signaling was inhibited. Indeed, vesicular stomatitis virus could directly upregulate BST-2 during infection of mouse embryonic fibroblasts through a process that required IRF-7 but was independent from the type I IFN cascade; however, in order to achieve optimal BST-2 induction, the type I IFN cascade needed to be engaged through activation of IRF-3. Furthermore, using human peripheral blood mononuclear cells, we show that BST-2 upregulation is part of an early intrinsic immune response since TLR8 and TLR3 agonists, known to trigger pathways that mediate activation of IRF proteins, could upregulate BST-2 prior to engagement of the type I IFN pathway. Collectively, our findings reveal that BST2 is activated by the same signals that trigger type I IFN production, outlining a regulatory mechanism ensuring that production of type I IFN and expression of a host restriction factor involved in the IFN negative-feedback loop are closely coordinated.
Collapse
|
50
|
Tetherin is a key effector of the antiretroviral activity of type I interferon in vitro and in vivo. Proc Natl Acad Sci U S A 2011; 108:18097-101. [PMID: 22025715 DOI: 10.1073/pnas.1113694108] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Tetherin (Bst-2 CD317) is a cell-surface protein whose expression is induced by IFNα. Although tetherin expression causes the retention of retrovirus particles on the surface of infected cells, it is not known whether tetherin inhibits retroviral replication or pathogenesis in vivo. Mutation of tetherin antagonists often has little effect on retroviral replication in vitro, and, although tetherin can reduce the yield of extracellular viral particles, some studies suggest that tetherin actually enhances direct cell-to-cell viral transmission. We generated tetherin-deficient mice to determine the effect of this protein on murine retrovirus replication and pathogenesis. We find that tetherin markedly inhibits the replication of Moloney murine leukemia virus (Mo-MLV) and is required for the antiretroviral activity of IFNα to be fully manifested in vitro. Surprisingly, Mo-MLV replication and disease progression was not significantly different in WT and tetherin-deficient mice, but this finding was explained by the fact that Mo-MLV infection did not induce detectable tetherin expression on candidate target cells in vivo. Indeed, IFNα induction was required to reveal the anti-Mo-MLV activity of tetherin in vivo. Moreover, LP-BM5, an MLV strain that has been demonstrated to induce immune activation and IFNα expression, achieved higher levels of viremia and induced exaggerated pathology in tetherin-deficient mice. These data indicate that tetherin is a bona fide antiviral protein and can reduce retroviral replication and disease in vivo.
Collapse
|