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Timilsina U, Ivey EB, Duffy S, Plianchaisuk A, The Genotype to Phenotype Japan (G2P-Japan) Consortium, Ito J, Sato K, Stavrou S. SARS-CoV-2 ORF7a Mutation Found in BF.5 and BF.7 Sublineages Impacts Its Functions. Int J Mol Sci 2024; 25:2351. [PMID: 38397027 PMCID: PMC10889720 DOI: 10.3390/ijms25042351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 02/06/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
A feature of the SARS-CoV-2 Omicron subvariants BF.5 and BF.7 that recently circulated mainly in China and Japan was the high prevalence of the ORF7a: H47Y mutation, in which the 47th residue of ORF7a has been mutated from a histidine (H) to a tyrosine (Y). Here, we evaluated the effect of this mutation on the three main functions ascribed to the SARS-CoV-2 ORF7a protein. Our findings show that H47Y mutation impairs the ability of SARS-CoV-2 ORF7a to antagonize the type I interferon (IFN-I) response and to downregulate major histocompatibility complex I (MHC-I) cell surface levels, but had no effect in its anti-SERINC5 function. Overall, our results suggest that the H47Y mutation of ORF7a affects important functions of this protein, resulting in changes in virus pathogenesis.
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Affiliation(s)
- Uddhav Timilsina
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA; (U.T.); (E.B.I.); (S.D.)
| | - Emily B. Ivey
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA; (U.T.); (E.B.I.); (S.D.)
| | - Sean Duffy
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA; (U.T.); (E.B.I.); (S.D.)
| | - Arnon Plianchaisuk
- Division of Systems Virology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8369, Japan; (A.P.); (J.I.); (K.S.)
| | | | - Jumpei Ito
- Division of Systems Virology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8369, Japan; (A.P.); (J.I.); (K.S.)
| | - Kei Sato
- Division of Systems Virology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8369, Japan; (A.P.); (J.I.); (K.S.)
- International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8369, Japan
- Graduate School of Medicine, The University of Tokyo, Tokyo 113-8654, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8581, Japan
- International Vaccine Design Center, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
- Collaboration Unit for Infection, Joint Research Center for Human Retrovirus Infection, Kumamoto University, Kumamoto 860-0862, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan
| | - Spyridon Stavrou
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA; (U.T.); (E.B.I.); (S.D.)
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Umthong S, Timilsina U, D’Angelo M, Stavrou S. Determining the antiviral mechanism of MARCH2. bioRxiv 2023:2023.09.18.558306. [PMID: 37786722 PMCID: PMC10541590 DOI: 10.1101/2023.09.18.558306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Membrane-associated RING-CH (MARCH) 2 protein is a member of the MARCH protein family of RING-CH finger E3 ubiquitin ligases that have important functions in regulating the levels of proteins found on the cell surface. MARCH1, 2 and 8 inhibit HIV-1 infection by preventing the incorporation of the envelope glycoproteins in nascent virions. However, a better understanding on the mechanism utilized by MARCH proteins to restrict HIV-1 is needed. In this report, we identify an amino acid in human MARCH2, that is absent in mouse MARCH2, critical for its antiretroviral function. Moreover, we map the domains of human MARCH2 critical for restricting as well as binding to the HIV-1 envelope glycoproteins. Our findings reveal important new aspects of the antiviral mechanism utilized by human MARCH2 to restrict HIV-1 that have potential implications to all MARCH proteins with antiviral functions.
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Affiliation(s)
- Supawadee Umthong
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
- Department of Biochemistry and Microbiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
| | - Uddhav Timilsina
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - Mary D’Angelo
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - Spyridon Stavrou
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
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Timilsina U, Stavrou S. SERINC5: One antiviral factor to bind them all. PLoS Pathog 2023; 19:e1011076. [PMID: 36656836 PMCID: PMC9851522 DOI: 10.1371/journal.ppat.1011076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Uddhav Timilsina
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, New York, United States of America
| | - Spyridon Stavrou
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, New York, United States of America
- * E-mail:
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Ghimire D, Kc Y, Timilsina U, Goel K, Nitz TJ, Wild CT, Gaur R. A single G10T polymorphism in HIV-1 subtype C Gag-SP1 regulates sensitivity to maturation inhibitors. Retrovirology 2021; 18:9. [PMID: 33836787 PMCID: PMC8033686 DOI: 10.1186/s12977-021-00553-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/23/2021] [Indexed: 08/30/2023] Open
Abstract
BACKGROUND Maturation inhibitors (MIs) potently block HIV-1 maturation by inhibiting the cleavage of the capsid protein and spacer peptide 1 (CA-SP1). Bevirimat (BVM), a highly efficacious first-in-class MI against HIV-1 subtype B isolates, elicited sub-optimal efficacy in clinical trials due to polymorphisms in the CA-SP1 region of the Gag protein (SP1:V7A). HIV-1 subtype C inherently contains this polymorphism thus conferring BVM resistance, however it displayed sensitivity to second generation BVM analogs. RESULTS In this study, we have assessed the efficacy of three novel second-generation MIs (BVM analogs: CV-8611, CV-8612, CV-8613) against HIV-1 subtype B and C isolates. The BVM analogs were potent inhibitors of both HIV-1 subtype B (NL4-3) and subtype C (K3016) viruses. Serial passaging of the subtype C, K3016 virus strain in the presence of BVM analogs led to identification of two mutant viruses-Gag SP1:A1V and CA:I201V. While the SP1:A1V mutant was resistant to the MIs, the CA:I120V mutant displayed partial resistance and a MI-dependent phenotype. Further analysis of the activity of the BVM analogs against two additional HIV-1 subtype C strains, IndieC1 and ZM247 revealed that they had reduced sensitivity as compared to K3016. Sequence analysis of the three viruses identified two polymorphisms at SP1 residues 9 and 10 (K3016: N9, G10; IndieC1/ZM247: S9, T10). The N9S and S9N mutants had no change in MI-sensitivity. On the other hand, replacing glycine at residue 10 with threonine in K3016 reduced its MI sensitivity whereas introducing glycine at SP1 10 in place of threonine in IndieC1 and ZM247 significantly enhanced their MI sensitivity. Thus, the specific glycine residue 10 of SP1 in the HIV-1 subtype C viruses determined sensitivity towards BVM analogs. CONCLUSIONS We have identified an association of a specific glycine at position 10 of Gag-SP1 with an MI susceptible phenotype of HIV-1 subtype C viruses. Our findings have highlighted that HIV-1 subtype C viruses, which were inherently resistant to BVM, may also be similarly predisposed to exhibit a significant degree of resistance to second-generation BVM analogs. Our work has strongly suggested that genetic differences between HIV-1 subtypes may produce variable MI sensitivity that needs to be considered in the development of novel, potent, broadly-active MIs.
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Affiliation(s)
- Dibya Ghimire
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, 110021, India
| | - Yuvraj Kc
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, 110021, India
| | - Uddhav Timilsina
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, 110021, India.,Department of Microbiology and Immunology, University at Buffalo, Buffalo, NY, 14203, USA
| | - Kriti Goel
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, 110021, India
| | - T J Nitz
- DFH Pharma, Gaithersburg, MD, 20886, USA
| | | | - Ritu Gaur
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, 110021, India.
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Umthong S, Lynch B, Timilsina U, Waxman B, Ivey EB, Stavrou S. Elucidating the Antiviral Mechanism of Different MARCH Factors. mBio 2021; 12:e03264-20. [PMID: 33653895 PMCID: PMC8092282 DOI: 10.1128/mbio.03264-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/22/2021] [Indexed: 12/13/2022] Open
Abstract
The membrane-associated RING-CH (MARCH) proteins belong to a family of E3 ubiquitin ligases, whose main function is to remove transmembrane proteins from the plasma membrane. Recent work has shown that the human MARCH1, 2, and 8 are antiretroviral factors that target the human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins by reducing their incorporation in the budding virions. Nevertheless, the dearth of information regarding the antiviral mechanism of this family of proteins necessitates further examination. In this study, using both the human MARCH proteins and their mouse homologues, we provide a comprehensive analysis of the antiretroviral mechanism of this family of proteins. Moreover, we show that human MARCH proteins restrict to various degrees the envelope glycoproteins of a diverse number of viruses. This report sheds light on the important antiviral function of MARCH proteins and their significance in cell intrinsic immunity.IMPORTANCE This study examines the mechanism utilized by different MARCH proteins to restrict retrovirus infection. MARCH proteins block the incorporation of envelope glycoproteins to the budding virions. In this report, by comparing the human and mouse MARCH genes and using murine leukemia virus (MLV) and HIV-1, we identify differences in the mechanism of restriction among MARCH proteins. Furthermore, we perform a comprehensive analysis on a number of envelope glycoproteins and show that MARCH proteins have broad antiviral functions.
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Affiliation(s)
- Supawadee Umthong
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Brian Lynch
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Uddhav Timilsina
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Brandon Waxman
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Emily B Ivey
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Spyridon Stavrou
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
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Sengupta D, Timilsina U, Mazumder ZH, Mukherjee A, Ghimire D, Markandey M, Upadhyaya K, Sharma D, Mishra N, Jha T, Basu S, Gaur R. Dual activity of amphiphilic Zn(II) nitroporphyrin derivatives as HIV-1 entry inhibitors and in cancer photodynamic therapy. Eur J Med Chem 2019; 174:66-75. [PMID: 31029945 DOI: 10.1016/j.ejmech.2019.04.051] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/16/2019] [Accepted: 04/17/2019] [Indexed: 12/31/2022]
Abstract
Two Zn(II) nitro porphyrin derivatives bearing combinations of meso-4-nitrophenyl and meso-4-methylpyridinium moieties and their free-base precursors were synthesized through one-pot microwave process, purified and characterized. The biological activity of these nitroporphyrins was assessed under both photodynamic and non-photodynamic conditions to correlate their structure-activity relationship (SAR). Unlike, the free-base precursors, Zn(II) complexes of these nitroporphyrins displayed nearly complete inhibition in the entry of lentiviruses such as HIV-1 and SIVmac under non-photodynamic conditions. In addition, the Zn(II) complexes also exhibited a higher in vitro photodynamic activity towards human lung cancer cell-line A549 than their free-base precursors. Our results strongly suggest that incorporation of Zn(II) has improved the antiviral and anticancer properties of the nitroporphyrins. To the best of our knowledge, this is the first report demonstrating the dual activity of nitroporphyrin-zinc complexes as antiviral and anti-cancer, which will aid in their development as therapeutics in clinics.
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Affiliation(s)
- Devashish Sengupta
- Department of Chemistry, Assam University, Silchar, Assam, 788011, India.
| | - Uddhav Timilsina
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, 110021, India
| | | | - Avinaba Mukherjee
- Department of Zoology, Charuchandra College, Kolkata, 700029, West Bengal, India
| | - Dibya Ghimire
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, 110021, India
| | - Manasvini Markandey
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, 110021, India
| | - Kalpana Upadhyaya
- Department of Chemistry, Assam University, Silchar, Assam, 788011, India
| | - Debdulal Sharma
- Department of Chemistry, Assam University, Silchar, Assam, 788011, India
| | - Nawneet Mishra
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, 110021, India
| | - Tarun Jha
- Department of Pharmaceutical Technology, Jadavpur University, Kolkata, 700032, West Bengal, India
| | - Samita Basu
- Chemical Science Division, Saha Institute of Nuclear Physics, Kolkata, 700064, West Bengal, India
| | - Ritu Gaur
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, 110021, India.
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Urano E, Timilsina U, Kaplan JA, Ablan S, Ghimire D, Pham P, Kuruppu N, Mandt R, Durell SR, Nitz TJ, Martin DE, Wild CT, Gaur R, Freed EO. Resistance to Second-Generation HIV-1 Maturation Inhibitors. J Virol 2019; 93:e02017-18. [PMID: 30567982 PMCID: PMC6401422 DOI: 10.1128/jvi.02017-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 12/10/2018] [Indexed: 12/26/2022] Open
Abstract
A betulinic acid-based compound, bevirimat (BVM), inhibits HIV-1 maturation by blocking a late step in protease-mediated Gag processing: the cleavage of the capsid-spacer peptide 1 (CA-SP1) intermediate to mature CA. Previous studies showed that mutations conferring resistance to BVM cluster around the CA-SP1 cleavage site. Single amino acid polymorphisms in the SP1 region of Gag and the C terminus of CA reduced HIV-1 susceptibility to BVM, leading to the discontinuation of BVM's clinical development. We recently reported a series of "second-generation" BVM analogs that display markedly improved potency and breadth of activity relative to the parent molecule. Here, we demonstrate that viral clones bearing BVM resistance mutations near the C terminus of CA are potently inhibited by second-generation BVM analogs. We performed de novo selection experiments to identify mutations that confer resistance to these novel compounds. Selection experiments with subtype B HIV-1 identified an Ala-to-Val mutation at SP1 residue 1 and a Pro-to-Ala mutation at CA residue 157 within the major homology region (MHR). In selection experiments with subtype C HIV-1, we identified mutations at CA residue 230 (CA-V230M) and SP1 residue 1 (SP1-A1V), residue 5 (SP1-S5N), and residue 10 (SP1-G10R). The positions at which resistance mutations arose are highly conserved across multiple subtypes of HIV-1. We demonstrate that the mutations confer modest to high-level maturation inhibitor resistance. In most cases, resistance was not associated with a detectable increase in the kinetics of CA-SP1 processing. These results identify mutations that confer resistance to second-generation maturation inhibitors and provide novel insights into the mechanism of resistance.IMPORTANCE HIV-1 maturation inhibitors are a class of small-molecule compounds that block a late step in the viral protease-mediated processing of the Gag polyprotein precursor, the viral protein responsible for the formation of virus particles. The first-in-class HIV-1 maturation inhibitor bevirimat was highly effective in blocking HIV-1 replication, but its activity was compromised by naturally occurring sequence polymorphisms within Gag. Recently developed bevirimat analogs, referred to as "second-generation" maturation inhibitors, overcome this issue. To understand more about how these second-generation compounds block HIV-1 maturation, here we selected for HIV-1 mutants that are resistant to these compounds. Selections were performed in the context of two different subtypes of HIV-1. We identified a small set of mutations at highly conserved positions within the capsid and spacer peptide 1 domains of Gag that confer resistance. Identification and analysis of these maturation inhibitor-resistant mutants provide insights into the mechanisms of resistance to these compounds.
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Affiliation(s)
- Emiko Urano
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Uddhav Timilsina
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, India
| | - Justin A Kaplan
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Sherimay Ablan
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Dibya Ghimire
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, India
| | - Phuong Pham
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Nishani Kuruppu
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Rebecca Mandt
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Stewart R Durell
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | | | | | | | - Ritu Gaur
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, India
| | - Eric O Freed
- Virus-Cell Interaction Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
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Abstract
Proteasome inhibitors (PIs) have been identified as an emerging class of HIV-1 latency-reversing agents (LRAs). These inhibitors can reactivate latent HIV-1 to produce non-infectious viruses. The mechanism underlying reduced infectivity of reactivated viruses is unknown. In this study, we analysed PI-reactivated viruses using biochemical and virological assays and demonstrated that these PIs stabilized the cellular expression of HIV-1 restriction factor, APOBEC3G, facilitating its packaging in the released viruses. Using infectivity assay and immunoblotting, we observed that the reduction in viral infectivity was due to enhanced levels of functionally active APOBEC3 proteins packaged in the virions. Sequencing of the proviral genome in the target cells revealed the presence of APOBEC3 signature hypermutations. Our study strengthens the role of PIs as bifunctional LRAs and demonstrates that the loss of infectivity of reactivated HIV-1 virions may be due to the increased packaging of APOBEC3 proteins in the virus.
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Affiliation(s)
- Uddhav Timilsina
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi-110021, Delhi
| | - Dibya Ghimire
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi-110021, Delhi
| | - Shilpa Sharma
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi-110021, Delhi
| | - Ritu Gaur
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi-110021, Delhi
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Mishra N, Reddy KS, Timilsina U, Gaur D, Gaur R. Human APOBEC3B interacts with the heterogenous nuclear ribonucleoprotein A3 in cancer cells. J Cell Biochem 2018; 119:6695-6703. [PMID: 29693745 DOI: 10.1002/jcb.26855] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 03/09/2018] [Indexed: 11/07/2022]
Abstract
Human APOBEC3B (A3B), like other APOBEC3 members, is a cytosine deaminase which causes hypermutation of single stranded genome. Recent studies have shown that A3B is predominantly elevated in multiple cancer tissues and cell lines such as the bladder, cervix, lung, head and neck, and breast. Upregulation and activation of A3B in developing tumors can cause an unexpected cluster of mutations which promote cancer development and progression. The cellular proteins which facilitate A3B function through direct or indirect interactions remain largely unknown. In this study, we performed LC-MS-based proteomics to identify cellular proteins which coimmunoprecipitated with A3B. Our results indicated a specific interaction of A3B with hnRNP A3 (heterogeneous nuclear ribonucleoprotein). This interaction was verified by co-immunoprecipitation and was found to be RNA-dependent. Furthermore, A3B and hnRNP A3 colocalized as evident from immunofluorescence analysis.
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Affiliation(s)
- Nawneet Mishra
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, India
| | - K Sony Reddy
- School of Biotechnology, KIIT University, Odisha, India
| | - Uddhav Timilsina
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, India
| | - Deepak Gaur
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Ritu Gaur
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, India
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Giri GR, Timilsina U. Apoptosis: Implications in Viral and Mycobacterium tuberculosis infections. Nepal J Biotechnol 2017. [DOI: 10.3126/njb.v5i1.18869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Apoptosis is a form of programmed cell death leading to genetically controlled self-destruction of cells. It is essential in the development, maintenance, and regulation of cells during physiological as well as pathological conditions. Deregulation of apoptotic mechanisms is associated with various pathological diseases including cancer, autoimmune disorders, viral and bacterial infections. Virus and Mycobacterium tuberculosis elicit host cell apoptosis as a part of host immune defense or pathogen dissemination. They inhibit both extrinsic and intrinsic pathways of apoptotic mechanisms facilitating pathogen survival and escape from host immune defense.Nepal Journal of Biotechnology. Dec. 2017 Vol. 5, No. 1: 46- 57
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Mishra N, Timilsina U, Ghimire D, Dubey RC, Gaur R. Downregulation of cytochrome c oxidase subunit 7A1 expression is important in enhancing cell proliferation in adenocarcinoma cells. Biochem Biophys Res Commun 2017; 482:713-719. [DOI: 10.1016/j.bbrc.2016.11.100] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 11/17/2016] [Indexed: 10/20/2022]
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Timilsina U, Gaur R. Modulation of apoptosis and viral latency - an axis to be well understood for successful cure of human immunodeficiency virus. J Gen Virol 2016; 97:813-824. [PMID: 26764023 DOI: 10.1099/jgv.0.000402] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Human immunodeficiency virus (HIV) is the causative agent of the deadly disease AIDS, which is characterized by the progressive decline of CD4(+)T-cells. HIV-1-encoded proteins such as envelope gp120 (glycoprotein gp120), Tat (trans-activator of transcription), Nef (negative regulatory factor), Vpr (viral protein R), Vpu (viral protein unique) and protease are known to be effective in modulating host cell signalling pathways that lead to an alteration in apoptosis of both HIV-infected and uninfected bystander cells. Depending on the stage of the virus life cycle and host cell type, these viral proteins act as mediators of pro- or anti-apoptotic signals. HIV latency in viral reservoirs is a persistent phenomenon that has remained beyond the control of the human immune system. To cure HIV infections completely, it is crucial to reactivate latent HIV from cellular pools and to drive these apoptosis-resistant cells towards death. Several previous studies have reported the role of HIV-encoded proteins in apoptosis modulation, but the molecular basis for apoptosis evasion of some chronically HIV-infected cells and reactivated latently HIV-infected cells still needs to be elucidated. The current review summarizes our present understanding of apoptosis modulation in HIV-infected cells, uninfected bystander cells and latently infected cells, with a focus on highlighting strategies to activate the apoptotic pathway to kill latently infected cells.
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Affiliation(s)
- Uddhav Timilsina
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi- 110021, India
| | - Ritu Gaur
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi- 110021, India
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Tamang HK, Timilsina U, Singh KP, Shrestha S, Raman RK, Panta P, Karna P, Khadka L, Dahal C. Apo B/Apo A-I Ratio is Statistically A Better Predictor of Cardiovascular Disease (CVD) than Conventional Lipid Profile: A Study from Kathmandu Valley, Nepal. J Clin Diagn Res 2014; 8:34-6. [PMID: 24701475 DOI: 10.7860/jcdr/2014/7588.4000] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 11/25/2013] [Indexed: 11/24/2022]
Abstract
BACKGROUND Apo B and Apo A-I, are structural and functional components of lipoprotein particles that serve as transporters of cholesterol. The apo B/apo A-I ratio reflects the cholesterol transport and has been shown to be strongly related to risk of Myocardial infarction, stroke and other Cardiovascular manifestations. MATERIALS AND METHODS Forty five participants with Cardiovascular Disease (CVD) and forty four healthy participants were included from different locations of Kathmandu valley, Nepal. Fasting blood samples were collected from ante-cubital vein and serum samples were used for lipid parameters, apo B and apo A-I levels measurement. RESULTS Statistically significant differences were found for apo B/apo A-I ratio, HDL-c and apo B between the groups. The other lipid parameters and lipid ratios such as total cholesterol, triglyceride, low density lipoprotein, TC/HDL-c, TG/HDL-c and LDL-c/HDL-c were not found to be significant. CONCLUSION Apo B/apo A-I ratio seems to have better predictive value than that of classical lipid parameters in cardiovascular risk assessment.
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Affiliation(s)
- Hem Kumar Tamang
- Lecturer, Department of Biochemistry, Kantipur Dental College Teaching Hospital , Dhapasi, Basundhara, Kathamandu, Nepal
| | - Uddhav Timilsina
- Phd Scholar, Department of Life Sciences and Biotechnology, South Asian University , New Delhi, India
| | - Khelanand Prasad Singh
- Lecturer, Department of Biochemistry, Institute of Medicine (TUTH) , Maharajgunj, Kathmandu, Nepal
| | - Sanjit Shrestha
- Medical Laboratory Technologist, Department of Pathology, Kathmandu Model Hospital , Exhibition Road, Kathmandu, Nepal
| | - Ramendra Kumar Raman
- Lecturer, Department of Anatomy, Kantipur Dental college Teaching Hospital , Dhapasi, Basundhara, Kathmandu, Nepal
| | - Pujan Panta
- Faculty, Department of Medical Laboratory Technology, Nobel College , Sinamangal, Kathmandu, Nepal
| | - Preeti Karna
- Faculty, Department of Medical Laboratory Technology, Nobel College , Sinamangal, Kathmandu, Nepal
| | - Laxmi Khadka
- Faculty, Department of Medical Laboratory Technology, Nobel College , Sinamangal, Kathmandu, Nepal
| | - Chandika Dahal
- Faculty, Department of Medical Laboratory Technology, Nobel College , Sinamangal, Kathmandu, Nepal
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Tamang HK, Timilsina U, Singh KP, Shrestha S, Pandey B, Basnet S, Waiba B, Shrestha U. Assessment of adiponectin level in obese and lean Nepalese population and its possible correlation with lipid profile: A cross-sectional study. Indian J Endocrinol Metab 2013; 17:S349-S354. [PMID: 24251211 PMCID: PMC3830357 DOI: 10.4103/2230-8210.119618] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE Adiponectin- one of the most important adipokines plays a pivotal role in carbohydrate and lipid metabolism and vascular biology. Changing food trend and lifestyle has tremendously affected the health status of Nepalese population. Studies have shown that between 1996 and 2006 obesity in Nepal has increased from 1.6% to 10%. Studies have been conducted in Nepal on the prevalence of obesity and its correlation with lipid profile. But based on our knowledge, this is the first study correlating adiponectin with obesity and lipid profile in Nepal. This piece of work will certainly help to assess the impact of obesity in Nepalese population. MATERIALS AND METHODS Fifty four obese and Thirty six normal/lean participants were included from different locations of Kathmandu Valley. Anthropometric measurements like age, BMI, Waist circumference, hip circumference, waist to hip ratio, mid thigh circumference and chest circumferences were taken from each participant. Blood glucose, lipid profile and serum adiponectin levels were measured from overnight fasting samples. RESULTS Significant differences were observed in BMI, Waist Circumference, Hip Circumference, Waist to Hip Ratio (WHR) and Chest circumference between obese and normal groups. Fasting Blood Glucose, Serum Triglyceride, HDL Cholesterol, LDL Cholesterol, Total Cholesterol/HDL ratio, Non-HDL Cholesterol and Adiponectin Levels were significant between the groups. Inverse correlations were observed between adiponectin level and BMI, Waist Circumference, Hip Circumference, Waist to Hip ratio, Chest Circumference, Fasting Blood Glucose, Triglyceride, Total Cholesterol/HDL ratio, LDL/HDL Cholesterol ratio and Non-HDL Cholesterol levels. Positive correlation was found between adiponectin and HDL Cholesterol levels. CONCLUSION Our study showed significant inverse association of serum adiponectin with obesity and lipid profile parameters except for Serum HDL Cholesterol level in Nepalese population.
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Affiliation(s)
- Hem K. Tamang
- Department of Biochemistry, Kantipur Dental College Teaching Hospital, Kathmandu, Nepal
| | - Uddhav Timilsina
- Department of Medical Laboratory Technology, Kantipur Academy of Health Science, Kathmandu, Nepal
| | - Khelanand P. Singh
- Department of Biochemistry, Institute of Medicine (TUTH), Kathmandu, Nepal
| | - Sanjit Shrestha
- Department of Pathology, Kathmandu Model Hospital, Kathmandu, Nepal
| | - Bishal Pandey
- Department of Laboratory Medicine, Nobel College, Kathmandu, Nepal
| | - Sameer Basnet
- Department of Laboratory Medicine, Nobel College, Kathmandu, Nepal
| | - Binod Waiba
- Department of Laboratory Medicine, Nobel College, Kathmandu, Nepal
| | - Umang Shrestha
- Department of Laboratory Medicine, Nobel College, Kathmandu, Nepal
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Tamang HK, Timilsina U, Thapa S, Singh KP, Shrestha S, Singh P, Shrestha B. Prevalence of metabolic syndrome among Nepalese type 2 diabetic patients. Nepal Med Coll J 2013; 15:50-55. [PMID: 24592795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This study was carried out to establish the prevalence of metabolic syndrome among the type 2 diabetic patients in Nepal. Two hundred twenty one participants aged 26-90 (mean age 53.41 +/- 13.30) years with established type 2 diabetes visiting Kathmandu Model Hospital, Kathmandu, Nepal from August 2011 to November 2011 were included in the study. National Cholesterol Education Adult Treatment Panel III (NCEP ATPIII) definition of the metabolic syndrome with ethnic threshold on abdominal obesity was used. 170 (76.9%) participants were found to have metabolic syndrome. Thirty two (14.5%) participants fulfilled all 5 criteria for metabolic syndrome, 63 (28.5%) participants had four criteria while three criteria were fulfilled by 75 (33.9%) of the participants. Among the patients having metabolic syndrome, hypertension was seen in 89 (52.35%) participants, raised serum triglyceride levels were found in 144 (84.70%) subjects, decreased serum HDL cholesterol levels were found in 119 (70%) participants while in 108 (63.35%) participants increased waist circumference was found. There was a higher frequency of metabolic syndrome in obese (81.58%) and in overweight (79.49%) subjects. This study indicates significant prevalence of metabolic syndrome among type 2 diabetic patients with strong association of obesity.
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Affiliation(s)
- H K Tamang
- Department of Biochemistry, Kantipur Dental College Teaching Hospital and Research Center, Kathmandu, Nepal.
| | - U Timilsina
- Department of Biotechnology, College for Professional Studies, Kathmandu, Nepal
| | - S Thapa
- Department of Biotechnology, College for Professional Studies, Kathmandu, Nepal
| | - K P Singh
- Department of Biochemistry, Maharajgunj Medical Campus (TUTH), Kathamandu, Nepal
| | - S Shrestha
- Department of Pathology, Kathmandu Model Hospital, Kathmandu, Nepal
| | - P Singh
- National College of Medical Sciences, Kathmandu, Nepal
| | - B Shrestha
- National College of Medical Sciences, Kathmandu, Nepal
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