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1.
Int J Mol Sci ; 25(4)2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38397027

RESUMO

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.


Assuntos
COVID-19 , Interferon Tipo I , Humanos , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , COVID-19/genética , Interferon Tipo I/metabolismo , Mutação , China
2.
bioRxiv ; 2023 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-37786722

RESUMO

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.

4.
Nat Commun ; 13(1): 2935, 2022 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-35618710

RESUMO

Serine Incorporator 5 (SERINC5), a cellular multipass transmembrane protein that is involved in sphingolipid and phosphatydilserine biogenesis, potently restricts a number of retroviruses, including Human Immunodeficiency Virus (HIV). SERINC5 is incorporated in the budding virions leading to the inhibition of virus infectivity. In turn, retroviruses, including HIV, encode factors that counteract the antiviral effect of SERINC5. While SERINC5 has been well studied in retroviruses, little is known about its role in other viral families. Due to the paucity of information regarding host factors targeting Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), we evaluated the effect of SERINC proteins on SARS-CoV-2 infection. Here, we show SERINC5 inhibits SARS-CoV-2 entry by blocking virus-cell fusion, and SARS-CoV-2 ORF7a counteracts the antiviral effect of SERINC5 by blocking the incorporation of over expressed SERINC5 in budding virions.


Assuntos
COVID-19 , Infecções por HIV , Antivirais/farmacologia , Humanos , Proteínas de Membrana , SARS-CoV-2 , Vírion/fisiologia
5.
Virology ; 571: 34-38, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35460960

RESUMO

HIV-1 subtype C virus accounts for nearly 50% of the total HIV infections globally. Despite this high prevalence, our understanding of subtype C specific infections remains limited due to lack of an in vitro model system. This is the first report of construction and characterization of a full-length and infectious EGFP-tagged HIV-1 subtype C molecular clone. The EGFP gene was inserted in-frame between the Nef and Env sequence in the HIV genome. The recombinant virus displayed expression of viral genes, infectivity and replication kinetics similar to the parental virus. VSV-G pseudotyping of the recombinant virus led to enhancement of HIV infection. The presence of the EGFP gene provides a rapid, easy and quantitative measure of HIV infection by flow cytometry and fluorescence microscopy. This clone will serve as an extremely beneficial tool to study HIV-1 subtype C specific infections.


Assuntos
Infecções por HIV , HIV-1 , Células Clonais , Fluorescência , HIV-1/genética , Humanos , Replicação Viral
6.
Antiviral Res ; 195: 105183, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34626674

RESUMO

The likelihood of continued circulation of COVID-19 and its variants, and novel coronaviruses due to future zoonotic transmissions, combined with the current paucity of coronavirus antivirals, emphasize the need for improved screening in developing effective antivirals for the treatment of infection by SARS-CoV-2 (CoV2) and other coronaviruses. Here we report the development of a live-cell based assay for evaluating the intracellular function of the critical, highly-conserved CoV2 target, the Main 3C-like protease (Mpro). This assay is based on expression of native wild-type mature CoV2 Mpro, the function of which is quantitatively evaluated in living cells through cleavage of a biosensor leading to loss of fluorescence. Evaluation does not require cell harvesting, allowing for multiple measurements from the same cells facilitating quantification of Mpro inhibition, as well as recovery of function upon removal of inhibitory drugs. The pan-coronavirus Mpro inhibitor, GC376, was utilized in this assay and effective inhibition of intracellular CoV2 Mpro was found to be consistent with levels required to inhibit CoV2 infection of human lung cells. We demonstrate that GC376 is an effective inhibitor of intracellular CoV2 Mpro at low micromolar levels, while other predicted Mpro inhibitors, bepridil and alverine, are not. Results indicate this system can provide a highly effective high-throughput coronavirus Mpro screening system.


Assuntos
Técnicas Biossensoriais , Proteases 3C de Coronavírus/antagonistas & inibidores , Inibidores de Proteases/farmacologia , Pirrolidinas/farmacologia , SARS-CoV-2/enzimologia , Ácidos Sulfônicos/farmacologia , Avaliação Pré-Clínica de Medicamentos , Fluorescência , Células HEK293 , Humanos
7.
Retrovirology ; 18(1): 9, 2021 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-33836787

RESUMO

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.


Assuntos
Fármacos Anti-HIV/farmacologia , Regulação Viral da Expressão Gênica/genética , HIV-1/efeitos dos fármacos , HIV-1/genética , Polimorfismo Genético/efeitos dos fármacos , Fator de Transcrição Sp1/antagonistas & inibidores , Produtos do Gene gag do Vírus da Imunodeficiência Humana/genética , Linhagem Celular , Farmacorresistência Viral/genética , Células HEK293 , Humanos , Fator de Transcrição Sp1/genética , Succinatos/farmacologia , Triterpenos/farmacologia , Montagem de Vírus/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos
8.
mBio ; 12(2)2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33653895

RESUMO

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.


Assuntos
Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Proteínas do Envelope Viral/metabolismo , Animais , Células HEK293 , HIV-1/metabolismo , Humanos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Células NIH 3T3 , Ubiquitina-Proteína Ligases/classificação , Montagem de Vírus
9.
mBio ; 11(4)2020 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-32665269

RESUMO

The serine incorporator (SERINC) proteins are multipass transmembrane proteins that affect sphingolipid and phosphatidylserine synthesis. Human SERINC5 and SERINC3 were recently shown to possess antiretroviral activity for a number of retroviruses, including human immunodeficiency virus (HIV), murine leukemia virus (MLV), and equine infectious anemia virus (EIAV). In the case of MLV, the glycosylated Gag (glyco-Gag) protein was shown to counteract SERINC5-mediated restriction in in vitro experiments and the viral envelope was found to determine virion sensitivity or resistance to SERINC5. However, nothing is known about the in vivo function of SERINC5. Antiretroviral function of a host factor in vitro is not always associated with antiretroviral function in vivo Using SERINC5-/- mice that we had generated, we showed that mouse SERINC5 (mSERINC5) restriction of MLV infection in vivo is influenced not only by glyco-Gag but also by the retroviral envelope. Finally, we also examined the in vivo function of the other SERINC gene with known antiretroviral functions, SERINC3. By using SERINC3-/- mice, we found that the murine homologue, mSERINC3, had no antiretroviral role either in vivo or in vitro To our knowledge, this report provides the first data showing that SERINC5 restricts retrovirus infection in vivo and that restriction of retrovirus infectivity in vivo is dependent on the presence of both glyco-Gag and the viral envelope.IMPORTANCE This study examined for the first time the in vivo function of the serine incorporator (SERINC) proteins during retrovirus infection. SERINC3 and SERINC5 (SERINC3/5) restrict a number of retroviruses, including human immunodeficiency virus 1 (HIV-1) and murine leukemia virus (MLV), by blocking their entry into cells. Nevertheless, HIV-1 and MLV encode factors, Nef and glycosylated Gag, respectively, that counteract SERINC3/5 in vitro We recently developed SERINC3 and SERINC5 knockout mice to examine the in vivo function of these genes. We found that SERINC5 restriction is dependent on the absence of glycosylated Gag and the expression of a specific viral envelope glycoprotein. On the other hand, SERINC3 had no antiviral function. Our findings have implications for the development of therapeutics that target SERINC5 during retrovirus infection.


Assuntos
Interações Hospedeiro-Patógeno , Leucemia Experimental/virologia , Proteínas de Membrana/genética , Infecções por Retroviridae/virologia , Infecções Tumorais por Vírus/virologia , Animais , Feminino , Glicosilação , Vírus da Leucemia Murina/patogenicidade , Masculino , Glicoproteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
10.
Eur J Med Chem ; 174: 66-75, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31029945

RESUMO

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.


Assuntos
Antineoplásicos/farmacologia , Inibidores da Fusão de HIV/farmacologia , Metaloporfirinas/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Zinco/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/efeitos da radiação , Antineoplásicos/toxicidade , Células CHO , Linhagem Celular Tumoral , Cricetulus , Fluorescência , Células HEK293 , Inibidores da Fusão de HIV/síntese química , Inibidores da Fusão de HIV/efeitos da radiação , Inibidores da Fusão de HIV/toxicidade , HIV-1/efeitos dos fármacos , Humanos , Luz , Metaloporfirinas/síntese química , Metaloporfirinas/efeitos da radiação , Metaloporfirinas/toxicidade , Estrutura Molecular , Nitrobenzenos/síntese química , Nitrobenzenos/farmacologia , Nitrobenzenos/efeitos da radiação , Nitrobenzenos/toxicidade , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/efeitos da radiação , Fármacos Fotossensibilizantes/toxicidade
11.
J Virol ; 93(6)2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30567982

RESUMO

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.


Assuntos
Fármacos Anti-HIV/farmacologia , Farmacorresistência Viral/efeitos dos fármacos , HIV-1/efeitos dos fármacos , Capsídeo/metabolismo , Proteínas do Capsídeo/metabolismo , Linhagem Celular , Soropositividade para HIV/tratamento farmacológico , Humanos , Células Jurkat , Mutação/efeitos dos fármacos , Triterpenos Pentacíclicos , Succinatos/farmacologia , Triterpenos/farmacologia , Vírion/efeitos dos fármacos , Montagem de Vírus/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Produtos do Gene gag do Vírus da Imunodeficiência Humana/metabolismo , Ácido Betulínico
12.
J Gen Virol ; 100(3): 523-532, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30566069

RESUMO

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.


Assuntos
Desaminase APOBEC-3G/metabolismo , Fármacos Anti-HIV/farmacologia , Citidina Desaminase/metabolismo , Infecções por HIV/enzimologia , HIV-1/fisiologia , Inibidores de Proteassoma/farmacologia , Latência Viral/efeitos dos fármacos , Desaminases APOBEC , Desaminase APOBEC-3G/genética , Citidina Desaminase/genética , Infecções por HIV/genética , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , HIV-1/genética , Humanos , Vírion/efeitos dos fármacos , Vírion/genética , Vírion/fisiologia , Ativação Viral/efeitos dos fármacos , Montagem de Vírus/efeitos dos fármacos
13.
Virology ; 521: 44-50, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29879541

RESUMO

HIV-1 Maturation inhibitors (MIs) bind to the C-terminal domain of capsid protein (CA-CTD) and spacer peptide 1 (SP1) in HIV-1 Gag and inhibit the CA-SP1 cleavage by stabilizing the immature Gag. The ß-turn motif, GVGGP in the HIV CA-CTD (residues 220-224) is one of the key determinants of HIV Gag assembly. In the present study, we mutated each residue of HIV-1 ß-turn motif to alanine and observed complete inhibition of virus release of all mutants. This defect in virus release was rescued in the presence of maturation inhibitors; BVM and PF-46396 for P224A mutant. To our knowledge, this is the first report of identification of BVM and PF-46396-dependent capsid mutant. Our results highlight the importance of the core ß-turn motif residues in immature virus assembly and suggest that the presence of MIs enhances Gag membrane binding and multimerization thereby restoring virus release of HIV Gag P224 mutant.


Assuntos
Fármacos Anti-HIV/farmacologia , Proteínas do Capsídeo/genética , HIV-1/genética , Mutação , Produtos do Gene gag do Vírus da Imunodeficiência Humana/metabolismo , Motivos de Aminoácidos/genética , Proteínas do Capsídeo/antagonistas & inibidores , Linhagem Celular , Genes gag , HIV-1/química , HIV-1/efeitos dos fármacos , Humanos , Linfócitos T/virologia , Montagem de Vírus/genética
14.
J Cell Biochem ; 119(8): 6695-6703, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29693745

RESUMO

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.


Assuntos
Citidina Desaminase/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/metabolismo , Antígenos de Histocompatibilidade Menor/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias/metabolismo , Linhagem Celular Tumoral , Citidina Desaminase/genética , Células HEK293 , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/genética , Humanos , Antígenos de Histocompatibilidade Menor/genética , Proteínas de Neoplasias/genética , Neoplasias/genética , Neoplasias/patologia , Ligação Proteica
15.
Sci Rep ; 7: 43711, 2017 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-28252110

RESUMO

HIV maturation inhibitors are an emerging class of anti-retroviral compounds that inhibit the viral protease-mediated cleavage of the Gag, CA-SP1 (capsid-spacer peptide 1) peptide to mature CA. The first-in-class maturation inhibitor bevirimat (BVM) displayed potent activity against HIV-1 clade B but was ineffective against other HIV-1 clades including clade C. Another pyridone-based maturation inhibitor, PF-46396 displayed potent activity against HIV-1 clade B. In this study, we aimed at determining the activity of PF-46396 against HIV-1 clade C. We employed various biochemical and virological assays to demonstrate that PF-46396 is effective against HIV-1 clade C. We observed a dose dependent accumulation of CA-SP1 intermediate in presence of the compound. We carried out mutagenesis in the CA- SP1 region of HIV-1 clade C Gag and observed that the mutations conferred resistance against the compound. Many mutations inhibited Gag processing thereby reducing virus release in the absence of the compound. However, presence of PF-46396 rescued these defects and enhanced virus release, replication capacity and infectivity of HIV-1 clade C. These results put together identify PF-46396 as a broadly active maturation inhibitor against HIV-1 clade B and C and help in rational designing of novel analogs with reduced toxicity and increased efficacy for its potential use in clinics.


Assuntos
Fármacos Anti-HIV/farmacologia , Genótipo , HIV-1/efeitos dos fármacos , HIV-1/genética , Motivos de Aminoácidos , Sequência de Aminoácidos , Fármacos Anti-HIV/química , Proteínas do Capsídeo/química , Proteínas do Capsídeo/metabolismo , Relação Dose-Resposta a Droga , Resistencia a Medicamentos Antineoplásicos , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , Protease de HIV/metabolismo , HIV-1/fisiologia , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Mutação , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Proteólise/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Produtos do Gene gag do Vírus da Imunodeficiência Humana/metabolismo
16.
Biochem Biophys Res Commun ; 482(4): 713-719, 2017 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-27866983

RESUMO

Mitochondrial Dysfunction has been implicated in multiple human diseases, including cancer. Among all cancer, lung cancer is the most common type of cancer worldwide with low survival rates. Mammals possess multiple subunits of the mitochondrial enzyme Cytochrome C oxidase (COX). The COX subunits are expressed in a tissue specific manner and have been implicated in cancer cell metabolism although their molecular and regulatory mechanisms are not clearly understood. In this study, we aimed at identifying novel gene signatures in lung cancer. We performed extensive analysis of seven different Gene Expression Omnibus (GEO) datasets pertaining to different stages of lung adenocarcinoma and identified that multiple subunits of COX genes are differentially expressed in these patients. Amongst all COX genes, the expression of COX7A1 gene was observed to be highly down regulated in these patients. In order to validate the GEO datasets, we looked at the expression of multiple COX genes using quantitative real time PCR (qPCR) using human lung adenocarcinoma cell line A549. Our results confirmed that COX 7A1 gene expression was indeed highly reduced in these cells. Overexpression of COX7A1 in human lung cancer cells led to inhibition of cell proliferation and increase in cell death via apoptosis. These results indicated that low level of COX7A1 gene expression is essential to regulate cell viability and inhibit cell death in lung adenocarcinoma. Our study has identified COX7A1 as a novel gene that might play a crucial role in the etiology of lung adenocarcinoma and can serve as a biomarker for lung cancer disease progression.


Assuntos
Adenocarcinoma/metabolismo , Regulação para Baixo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Perfilação da Expressão Gênica , Neoplasias Pulmonares/metabolismo , Células A549 , Adenocarcinoma de Pulmão , Apoptose , Benzimidazóis/química , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Progressão da Doença , Humanos , Neoplasias Pulmonares/patologia , Mitocôndrias/patologia , Fosforilação Oxidativa , Estresse Oxidativo
17.
Sci Rep ; 6: 27403, 2016 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-27264714

RESUMO

Antiretroviral therapy has led to a profound improvement in the clinical care of HIV-infected patients. However, drug tolerability and the evolution of drug resistance have limited treatment options for many patients. Maturation inhibitors are a new class of antiretroviral agents for treatment of HIV-1. They act by interfering with the maturation of the virus by blocking the last step in Gag processing: the cleavage of the capsid-spacer peptide 1 (CA-SP1) intermediate to mature CA by the viral protease (PR). The first-in-class maturation inhibitor bevirimat (BVM) failed against a subset of HIV-1 isolates in clinical trials due to polymorphisms present in the CA-SP1 region of the Gag protein. Sequence analysis indicated that these polymorphisms are more common in non-clade B strains of HIV-1 such as HIV-1 clade C. Indeed, BVM was found to be ineffective against HIV-1 clade C molecular clones tested in this study. A number of BVM analogs were synthesized by chemical modifications at the C-28 position to improve its activity. The new BVM analogs displayed potent activity against HIV-1 clade B and C and also reduced infectivity of the virus. This study identifies novel and broadly active BVM analogs that may ultimately demonstrate efficacy in the clinic.


Assuntos
Fármacos Anti-HIV/farmacologia , HIV-1/efeitos dos fármacos , Sequência de Aminoácidos , Linhagem Celular , Farmacorresistência Viral , HIV-1/patogenicidade , Humanos , Homologia de Sequência de Aminoácidos
18.
J Gen Virol ; 97(4): 813-824, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26764023

RESUMO

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.


Assuntos
Regulação da Expressão Gênica/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Interações Hospedeiro-Patógeno , Latência Viral/imunologia , Apoptose/genética , Apoptose/imunologia , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/imunologia , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD4-Positivos/virologia , Proteína gp120 do Envelope de HIV/genética , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/patologia , Infecções por HIV/virologia , Protease de HIV/genética , Protease de HIV/imunologia , HIV-1/genética , Proteínas do Vírus da Imunodeficiência Humana/genética , Proteínas do Vírus da Imunodeficiência Humana/imunologia , Humanos , Transdução de Sinais , Proteínas Virais Reguladoras e Acessórias/genética , Proteínas Virais Reguladoras e Acessórias/imunologia , Produtos do Gene nef do Vírus da Imunodeficiência Humana/genética , Produtos do Gene nef do Vírus da Imunodeficiência Humana/imunologia , Produtos do Gene tat do Vírus da Imunodeficiência Humana/genética , Produtos do Gene tat do Vírus da Imunodeficiência Humana/imunologia , Produtos do Gene vpr do Vírus da Imunodeficiência Humana/genética , Produtos do Gene vpr do Vírus da Imunodeficiência Humana/imunologia
19.
J Clin Diagn Res ; 8(2): 34-6, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24701475

RESUMO

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.

20.
Indian J Endocrinol Metab ; 17(Suppl 1): S349-54, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24251211

RESUMO

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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