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Sid Ahmed S, Bajak K, Fackler OT. Beyond Impairment of Virion Infectivity: New Activities of the Anti-HIV Host Cell Factor SERINC5. Viruses 2024; 16:284. [PMID: 38400059 PMCID: PMC10892966 DOI: 10.3390/v16020284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 02/07/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
Members of the serine incorporator (SERINC) protein family exert broad antiviral activity, and many viruses encode SERINC antagonists to circumvent these restrictions. Significant new insight was recently gained into the mechanisms that mediate restriction and antagonism. In this review, we summarize our current understanding of the mode of action and relevance of SERINC proteins in HIV-1 infection. Particular focus will be placed on recent findings that provided important new mechanistic insights into the restriction of HIV-1 virion infectivity, including the discovery of SERINC's lipid scramblase activity and its antagonism by the HIV-1 pathogenesis factor Nef. We also discuss the identification and implications of several additional antiviral activities by which SERINC proteins enhance pro-inflammatory signaling and reduce viral gene expression in myeloid cells. SERINC proteins emerge as versatile and multifunctional regulators of cell-intrinsic immunity against HIV-1 infection.
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Affiliation(s)
- Samy Sid Ahmed
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany; (S.S.A.); (K.B.)
| | - Kathrin Bajak
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany; (S.S.A.); (K.B.)
- German Centre for Infection Research (DZIF), Partner Site Heidelberg, 38124 Heidelberg, Germany
| | - Oliver T. Fackler
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Germany; (S.S.A.); (K.B.)
- German Centre for Infection Research (DZIF), Partner Site Heidelberg, 38124 Heidelberg, Germany
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Bhardwaj V, Singh A, Choudhary A, Dalavi R, Ralte L, Chawngthu RL, Senthil Kumar N, Vijay N, Chande A. HIV-1 Vpr induces ciTRAN to prevent transcriptional repression of the provirus. SCIENCE ADVANCES 2023; 9:eadh9170. [PMID: 37672576 PMCID: PMC10482341 DOI: 10.1126/sciadv.adh9170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 08/02/2023] [Indexed: 09/08/2023]
Abstract
The functional consequences of circular RNA (circRNA) expression on HIV-1 replication are largely unknown. Using a customized protocol involving direct RNA nanopore sequencing, here, we captured circRNAs from HIV-1-infected T cells and identified ciTRAN, a circRNA that modulates HIV-1 transcription. We found that HIV-1 infection induces ciTRAN expression in a Vpr-dependent manner and that ciTRAN interacts with SRSF1, a protein known to repress HIV-1 transcription. Our results suggest that HIV-1 hijacks ciTRAN to exclude serine/arginine-rich splicing factor 1 (SRSF1) from the viral transcriptional complex, thereby promoting efficient viral transcription. In addition, we demonstrate that an SRSF1-inspired mimic can inhibit viral transcription regardless of ciTRAN induction. The hijacking of a host circRNA thus represents a previously unknown facet of primate lentiviruses in overcoming transmission bottlenecks.
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Affiliation(s)
- Vipin Bhardwaj
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, India
| | - Aman Singh
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, India
| | - Aditi Choudhary
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, India
| | - Rishikesh Dalavi
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, India
| | | | | | | | - Nagarjun Vijay
- Computational and Evolutionary Genomics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, India
| | - Ajit Chande
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER), Bhopal, India
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Ramdas P, Chande A. SERINC5 Mediates a Postintegration Block to HIV-1 Gene Expression in Macrophages. mBio 2023; 14:e0016623. [PMID: 36976020 PMCID: PMC10127607 DOI: 10.1128/mbio.00166-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 03/01/2023] [Indexed: 03/29/2023] Open
Abstract
HIV-1 antagonizes SERINC5 by redundant mechanisms, primarily through Nef and additionally via envelope glycoprotein. Paradoxically, HIV-1 preserves Nef function to ensure the exclusion of SERINC5 from virion incorporation regardless of the availability of envelope that can confer resistance, suggesting additional roles of the virion-incorporated host factor. Here, we report an unusual mode of SERINC5 action in inhibiting viral gene expression. This inhibition is observed only in the myeloid lineage cells but not in the cells of epithelial or lymphoid origin. We found that SERINC5-bearing viruses induce the expression of RPL35 and DRAP1 in macrophages, and these host proteins intercept HIV-1 Tat from binding to and recruiting a mammalian capping enzyme (MCE1) to the HIV-1 transcriptional complex. As a result, uncapped viral transcripts are synthesized, leading to the inhibition of viral protein synthesis and subsequent progeny virion biogenesis. Cell-type-specific inhibition of HIV-1 gene expression thus exemplifies a novel antiviral function of virion-incorporated SERINC5. IMPORTANCE In addition to Nef, HIV-1 envelope glycoprotein has been shown to modulate SERINC5-mediated inhibition. Counterintuitively, Nef from the same isolates preserves the ability to prevent SERINC5 incorporation into virions, implying additional functions of the host protein. We identify that virion-associated SERINC5 can manifest an antiviral mechanism independent of the envelope glycoprotein to regulate HIV-1 gene expression in macrophages. This mechanism is exhibited by affecting the viral RNA capping and is plausibly adopted by the host to overcome the envelope glycoprotein-mediated resistance to SERINC5 restriction.
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Affiliation(s)
- Pavitra Ramdas
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh, India
| | - Ajit Chande
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh, India
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Mishra T, Bhardwaj V, Ahuja N, Gadgil P, Ramdas P, Shukla S, Chande A. Improved loss-of-function CRISPR-Cas9 genome editing in human cells concomitant with inhibition of TGF-β signaling. MOLECULAR THERAPY. NUCLEIC ACIDS 2022; 28:202-218. [PMID: 35402072 PMCID: PMC8961078 DOI: 10.1016/j.omtn.2022.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 03/03/2022] [Indexed: 11/29/2022]
Abstract
Strategies to modulate cellular DNA repair pathways hold immense potential to enhance the efficiency of CRISPR-Cas9 genome editing platform. In the absence of a repair template, CRISPR-Cas9-induced DNA double-strand breaks are repaired by the endogenous cellular DNA repair pathways to generate loss-of-function edits. Here, we describe a reporter-based assay for expeditious measurement of loss-of-function editing by CRISPR-Cas9. An unbiased chemical screen performed using this assay enabled the identification of small molecules that promote loss-of-function editing. Iterative rounds of screens reveal Repsox, a TGF-β signaling inhibitor, as a CRISPR-Cas9 editing efficiency enhancer. Repsox invariably increased CRISPR-Cas9 editing in a panel of commonly used cell lines in biomedical research and primary cells. Furthermore, Repsox-mediated editing enhancement in primary human CD4+ T cells enabled the generation of HIV-1-resistant cells with high efficiency. This study demonstrates the potential of transiently targeting cellular pathways by small molecules to improve genome editing for research applications and is expected to benefit gene therapy efforts.
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Affiliation(s)
- Tarun Mishra
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal 462066, India
| | - Vipin Bhardwaj
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal 462066, India
| | - Neha Ahuja
- Epigenetics and RNA Processing Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal 462066, India
| | - Pallavi Gadgil
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal 462066, India
| | - Pavitra Ramdas
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal 462066, India
| | - Sanjeev Shukla
- Epigenetics and RNA Processing Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal 462066, India
| | - Ajit Chande
- Molecular Virology Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal 462066, India
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Xu S, Zheng Z, Pathak JL, Cheng H, Zhou Z, Chen Y, Wu Q, Wang L, Zeng M, Wu L. The Emerging Role of the Serine Incorporator Protein Family in Regulating Viral Infection. Front Cell Dev Biol 2022; 10:856468. [PMID: 35433679 PMCID: PMC9010877 DOI: 10.3389/fcell.2022.856468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 03/09/2022] [Indexed: 11/25/2022] Open
Abstract
Serine incorporator (SERINC) proteins 1–5 (SERINC1-5) are involved in the progression of several diseases. SERINC2-4 are carrier proteins that incorporate the polar amino acid serine into membranes to facilitate the synthesis of phosphatidylserine and sphingolipids. SERINC genes are also differentially expressed in tumors. Abnormal expression of SERINC proteins occurs in human cancers of the breast, lung, colon, liver, and various glands, as well as in mouse testes. SERINC proteins also affect cleft lip and palate and nerve-related diseases, such as seizure Parkinsonism and borderline personality. Moreover, SERINC proteins have garnered significant interest as retroviral restriction factors, spurring efforts to define their function and elucidate the mechanisms through which they operate when associated with viruses. Human SERINC proteins possess antiviral potential against human immunodeficiency virus (HIV), SARS-COV-2, murine leukemia virus (MLV), equine infectious anemia virus (EIAV), and hepatitis B virus (HBV). Furthermore, the crystal structure is known, and the critical residues of SERINC5 that act against HIV have been identified. In this review, we discuss the most prevalent mechanisms by which SERINC3 and SERINC5 antagonize viruses and focus on the potential therapeutic applications of SERINC5/3 against HIV.
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Affiliation(s)
- Shaofen Xu
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Zhichao Zheng
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Basic Oral Medicine, Guangzhou Medical University School and Hospital of Stomatology, Guangzhou, China
| | - Janak L. Pathak
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Haoyu Cheng
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Ziliang Zhou
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Yanping Chen
- Center of Emphasis in Infectious Diseases, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
| | - Qiuyu Wu
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Lijing Wang
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
- Vascular Biology Research Institute, Guangdong Pharmaceutical University, Guangzhou Higher Education Mega Center, Guangzhou, China
- *Correspondence: Lihong Wu, ; Mingtao Zeng, ; Lijing Wang,
| | - Mingtao Zeng
- Center of Emphasis in Infectious Diseases, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
- *Correspondence: Lihong Wu, ; Mingtao Zeng, ; Lijing Wang,
| | - Lihong Wu
- Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
- Department of Basic Oral Medicine, Guangzhou Medical University School and Hospital of Stomatology, Guangzhou, China
- *Correspondence: Lihong Wu, ; Mingtao Zeng, ; Lijing Wang,
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Cano-Ortiz L, Luedde T, Münk C. HIV-1 restriction by SERINC5. Med Microbiol Immunol 2022; 212:133-140. [PMID: 35333966 PMCID: PMC10085909 DOI: 10.1007/s00430-022-00732-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/08/2022] [Indexed: 11/25/2022]
Abstract
Serine incorporator 5 (SERINC5 or SER5) is a multipass transmembrane protein with ill-defined cellular activities. SER5 was recently described as a human immunodeficiency virus 1 (HIV-1) restriction factor capable of inhibiting HIV-1 that does not express its accessory protein Nef (Δ Nef). SER5 incorporated into the viral membrane impairs the entry of HIV-1 by disrupting the fusion between the viral and the plasma membrane after envelope receptor interaction induced the first steps of the fusion process. The mechanisms of how SER5 prevents membrane fusion are not fully understood and viral envelope proteins were identified that escape the SER5-mediated restriction. Primate lentiviruses, such as HIV-1 and simian immunodeficiency viruses (SIVs), use their accessory protein Nef to downregulate SER5 from the plasma membrane by inducing an endocytic pathway. In addition to being directly antiviral, recent data suggest that SER5 is an important adapter protein in innate signaling pathways leading to the induction of inflammatory cytokines. This review discusses the current knowledge about HIV-1 restriction by SER5.
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Affiliation(s)
- Lucía Cano-Ortiz
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Building 23.12.U1.82, Moorenstr. 5, 40225, Düsseldorf, Germany
- Laboratório de Virologia, Departamento de Microbiologia, Imunologia e Parasitologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Tom Luedde
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Building 23.12.U1.82, Moorenstr. 5, 40225, Düsseldorf, Germany
| | - Carsten Münk
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Building 23.12.U1.82, Moorenstr. 5, 40225, Düsseldorf, Germany.
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