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1.
Nature ; 606(7912): 146-152, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35614219

RESUMO

Real-world memories are formed in a particular context and are often not acquired or recalled in isolation1-5. Time is a key variable in the organization of memories, as events that are experienced close in time are more likely to be meaningfully associated, whereas those that are experienced with a longer interval are not1-4. How the brain segregates events that are temporally distinct is unclear. Here we show that a delayed (12-24 h) increase in the expression of C-C chemokine receptor type 5 (CCR5)-an immune receptor that is well known as a co-receptor for HIV infection6,7-after the formation of a contextual memory determines the duration of the temporal window for associating or linking that memory with subsequent memories. This delayed expression of CCR5 in mouse dorsal CA1 neurons results in a decrease in neuronal excitability, which in turn negatively regulates neuronal memory allocation, thus reducing the overlap between dorsal CA1 memory ensembles. Lowering this overlap affects the ability of one memory to trigger the recall of the other, and therefore closes the temporal window for memory linking. Our findings also show that an age-related increase in the neuronal expression of CCR5 and its ligand CCL5 leads to impairments in memory linking in aged mice, which could be reversed with a Ccr5 knockout and a drug approved by the US Food and Drug Administration (FDA) that inhibits this receptor, a result with clinical implications. Altogether, the findings reported here provide insights into the molecular and cellular mechanisms that shape the temporal window for memory linking.


Assuntos
Região CA1 Hipocampal , Memória , Neurônios , Receptores CCR5 , Animais , Região CA1 Hipocampal/citologia , Região CA1 Hipocampal/fisiologia , Memória/fisiologia , Rememoração Mental/fisiologia , Camundongos , Neurônios/metabolismo , Receptores CCR5/deficiência , Receptores CCR5/genética , Receptores CCR5/metabolismo , Fatores de Tempo
2.
Mol Ther ; 32(5): 1311-1327, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38449314

RESUMO

While studying transgene expression after systemic administration of lentiviral vectors, we found that splenic B cells are robustly transduced, regardless of the types of pseudotyped envelope proteins. However, the administration of two different pseudotypes resulted in transduction of two distinct B cell populations, suggesting that each pseudotype uses unique and specific receptors for its attachment and entry into splenic B cells. Single-cell RNA sequencing analysis of the transduced cells demonstrated that different pseudotypes transduce distinct B cell subpopulations characterized by specific B cell receptor (BCR) genotypes. Functional analysis of the BCRs of the transduced cells demonstrated that BCRs specific to the pseudotyping envelope proteins mediate viral entry, enabling the vectors to selectively transduce the B cell populations that are capable of producing antibodies specific to their envelope proteins. Lentiviral vector entry via the BCR activated the transduced B cells and induced proliferation and differentiation into mature effectors, such as memory B and plasma cells. BCR-mediated viral entry into clonally specific B cell subpopulations raises new concepts for understanding the biodistribution of transgene expression after systemic administration of lentiviral vectors and offers new opportunities for BCR-targeted gene delivery by pseudotyped lentiviral vectors.


Assuntos
Linfócitos B , Vetores Genéticos , Lentivirus , Receptores de Antígenos de Linfócitos B , Transdução Genética , Transgenes , Proteínas do Envelope Viral , Lentivirus/genética , Receptores de Antígenos de Linfócitos B/metabolismo , Receptores de Antígenos de Linfócitos B/genética , Vetores Genéticos/genética , Vetores Genéticos/administração & dosagem , Animais , Camundongos , Linfócitos B/metabolismo , Linfócitos B/imunologia , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo , Tropismo Viral , Humanos , Internalização do Vírus
3.
Nature ; 534(7605): 115-8, 2016 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-27251287

RESUMO

Recent studies suggest that a shared neural ensemble may link distinct memories encoded close in time. According to the memory allocation hypothesis, learning triggers a temporary increase in neuronal excitability that biases the representation of a subsequent memory to the neuronal ensemble encoding the first memory, such that recall of one memory increases the likelihood of recalling the other memory. Here we show in mice that the overlap between the hippocampal CA1 ensembles activated by two distinct contexts acquired within a day is higher than when they are separated by a week. Several findings indicate that this overlap of neuronal ensembles links two contextual memories. First, fear paired with one context is transferred to a neutral context when the two contexts are acquired within a day but not across a week. Second, the first memory strengthens the second memory within a day but not across a week. Older mice, known to have lower CA1 excitability, do not show the overlap between ensembles, the transfer of fear between contexts, or the strengthening of the second memory. Finally, in aged mice, increasing cellular excitability and activating a common ensemble of CA1 neurons during two distinct context exposures rescued the deficit in linking memories. Taken together, these findings demonstrate that contextual memories encoded close in time are linked by directing storage into overlapping ensembles. Alteration of these processes by ageing could affect the temporal structure of memories, thus impairing efficient recall of related information.


Assuntos
Região CA1 Hipocampal/citologia , Região CA1 Hipocampal/fisiologia , Memória/fisiologia , Neurônios/fisiologia , Animais , Cálcio/análise , Medo , Masculino , Rememoração Mental/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Modelos Neurológicos , Fatores de Tempo
5.
PLoS Pathog ; 13(12): e1006753, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29284044

RESUMO

Chimeric Antigen Receptor (CAR) T-cells have emerged as a powerful immunotherapy for various forms of cancer and show promise in treating HIV-1 infection. However, significant limitations are persistence and whether peripheral T cell-based products can respond to malignant or infected cells that may reappear months or years after treatment remains unclear. Hematopoietic Stem/Progenitor Cells (HSPCs) are capable of long-term engraftment and have the potential to overcome these limitations. Here, we report the use of a protective CD4 chimeric antigen receptor (C46CD4CAR) to redirect HSPC-derived T-cells against simian/human immunodeficiency virus (SHIV) infection in pigtail macaques. CAR-containing cells persisted for more than 2 years without any measurable toxicity and were capable of multilineage engraftment. Combination antiretroviral therapy (cART) treatment followed by cART withdrawal resulted in lower viral rebound in CAR animals relative to controls, and demonstrated an immune memory-like response. We found CAR-expressing cells in multiple lymphoid tissues, decreased tissue-associated SHIV RNA levels, and substantially higher CD4/CD8 ratios in the gut as compared to controls. These results show that HSPC-derived CAR T-cells are capable of long-term engraftment and immune surveillance. This study demonstrates for the first time the safety and feasibility of HSPC-based CAR therapy in a large animal preclinical model.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Infecções por HIV/imunologia , Infecções por HIV/terapia , Células-Tronco Hematopoéticas/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/terapia , Animais , Linfócitos T CD4-Positivos/transplante , Diferenciação Celular/imunologia , Linhagem da Célula/imunologia , Modelos Animais de Doenças , Terapia Genética/métodos , Infecções por HIV/virologia , Transplante de Células-Tronco Hematopoéticas/métodos , Imunoterapia/métodos , Macaca nemestrina , Masculino , Receptores de Antígenos de Linfócitos T/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes de Fusão/metabolismo , Síndrome de Imunodeficiência Adquirida dos Símios/virologia
6.
Mol Ther ; 23(8): 1358-1367, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26050990

RESUMO

The human immunodeficiency virus (HIV)-specific cytotoxic T lymphocyte (CTL) response is critical in controlling HIV infection. Since the immune response does not eliminate HIV, it would be beneficial to develop ways to enhance the HIV-specific CTL response to allow long-term viral suppression or clearance. Here, we report the use of a protective chimeric antigen receptor (CAR) in a hematopoietic stem/progenitor cell (HSPC)-based approach to engineer HIV immunity. We determined that CAR-modified HSPCs differentiate into functional T cells as well as natural killer (NK) cells in vivo in humanized mice and these cells are resistant to HIV infection and suppress HIV replication. These results strongly suggest that stem cell-based gene therapy with a CAR may be feasible and effective in treating chronic HIV infection and other morbidities.


Assuntos
Infecções por HIV/imunologia , Células-Tronco Hematopoéticas/citologia , Receptores de Antígenos/química , Animais , Antígenos CD34/metabolismo , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD8-Positivos/citologia , Diferenciação Celular , Citocinas/metabolismo , Engenharia Genética/métodos , Terapia Genética/métodos , Vetores Genéticos , Células HEK293 , HIV-1 , Humanos , Células Matadoras Naturais/imunologia , Camundongos , Receptores de Antígenos de Linfócitos T/metabolismo , Baço/metabolismo , Baço/virologia , Linfócitos T Citotóxicos/imunologia
7.
Biochem Biophys Res Commun ; 463(3): 216-21, 2015 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-25998390

RESUMO

Chimeric antigen receptors (CARs) are artificially engineered receptors that confer a desired specificity to immune effector T cells. As an HIV-1-specific CAR, CD4ζ CAR has been extensively tested in vitro as well as in clinical trials. T cells modified with this CAR mediated highly potent anti-HIV-1 activities in vitro and were well-tolerated in vivo, but exerted limited effects on viral load and reservoir size due to poor survival and/or functionality of the transduced cells in patients. We hypothesize that ectopic expression of CD4ζ on CD8(+) T cells renders them susceptible to HIV-1 infection, resulting in poor survival of those cells. To test this possibility, highly purified CD8(+) T cells were genetically modified with a CD4ζ-encoding lentiviral vector and infected with HIV-1. CD8(+) T cells were vulnerable to HIV-1 infection upon expression of CD4ζ as evidenced by elevated levels of p24(Gag) in cells and culture supernatants. Concurrently, the number of CD4ζ-modified CD8(+) T cells was reduced relative to control cells upon HIV-1 infection. To protect these cells from HIV-1 infection, we co-expressed two anti-HIV-1 shRNAs previously developed by our group together with CD4ζ. This combination vector was able to suppress HIV-1 infection without impairing HIV-1-dependent effector activities of CD4ζ. In addition, the number of CD4ζ-modified CD8(+) T cells maintained similar levels to that of the control even under HIV-1 infection. These results suggest that protecting CD4ζ-modified CD8(+) T cells from HIV-1 infection is required for prolonged HIV-1-specific immune surveillance.


Assuntos
Antígenos CD4/imunologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/virologia , Infecções por HIV/terapia , HIV-1/imunologia , Imunoterapia , RNA Interferente Pequeno/imunologia , Antígenos CD4/genética , Engenharia Celular , Proliferação de Células , Células Cultivadas , Expressão Gênica , Infecções por HIV/imunologia , HIV-1/genética , Humanos , RNA Interferente Pequeno/genética
8.
Cancers (Basel) ; 15(6)2023 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-36980702

RESUMO

Transferrin receptor 1 (TfR1), also known as CD71, is a transmembrane protein involved in the cellular uptake of iron and the regulation of cell growth. This receptor is expressed at low levels on a variety of normal cells, but is upregulated on cells with a high rate of proliferation, including malignant cells and activated immune cells. Infection with the human immunodeficiency virus (HIV) leads to the chronic activation of B cells, resulting in high expression of TfR1, B-cell dysfunction, and ultimately the development of acquired immunodeficiency syndrome-related B-cell non-Hodgkin lymphoma (AIDS-NHL). Importantly, TfR1 expression is correlated with the stage and prognosis of NHL. Thus, it is a meaningful target for antibody-based NHL therapy. We previously developed a mouse/human chimeric IgG3 specific for TfR1 (ch128.1/IgG3) and showed that this antibody exhibits antitumor activity in an in vivo model of AIDS-NHL using NOD-SCID mice challenged intraperitoneally with 2F7 human Burkitt lymphoma (BL) cells that harbor the Epstein-Barr virus (EBV). We have also developed an IgG1 version of ch128.1 that shows significant antitumor activity in SCID-Beige mouse models of disseminated multiple myeloma, another B-cell malignancy. Here, we aim to explore the utility of ch128.1/IgG1 and its humanized version (hu128.1) in mouse models of AIDS-NHL. To accomplish this goal, we used the 2F7 cell line variant 2F7-BR44, which is more aggressive than the parental cell line and forms metastases in the brain of mice after systemic (intravenous) administration. We also used the human BL cell line JB, which in contrast to 2F7, is EBV-negative, allowing us to study both EBV-infected and non-infected NHL tumors. Treatment with ch128.1/IgG1 or hu128.1 of SCID-Beige mice challenged locally (subcutaneously) with 2F7-BR44 or JB cells results in significant antitumor activity against different stages of disease. Treatment of mice challenged systemically (intravenously) with either 2F7-BR44 or JB cells also showed significant antitumor activity, including long-term survival. Taken together, our results suggest that targeting TfR1 with antibodies, such as ch128.1/IgG1 or hu128.1, has potential as an effective therapy for AIDS-NHL.

9.
Front Cell Dev Biol ; 11: 1214118, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37920826

RESUMO

Antibody therapeutics are limited in treating brain diseases due to poor blood-brain barrier (BBB) penetration. We have discovered that poly 2-methacryloyloxyethyl phosphorylcholine (PMPC), a biocompatible polymer, effectively facilitates BBB penetration via receptor-mediated transcytosis and have developed a PMPC-shell-based platform for brain delivery of therapeutic antibodies, termed nanocapsule. Yet, the platform results in functional loss of antibodies due to epitope masking by the PMPC polymer network, which necessitates the incorporation of a targeting moiety and degradable crosslinker to enable on-site antibody release. In this study, we developed a novel platform based on site-oriented conjugation of PMPC to the antibody, allowing it to maintain key functionalities of the original antibody. With an optimized PMPC chain length, the PMPC-antibody conjugate exhibited enhanced brain delivery while retaining epitope recognition, cellular internalization, and antibody-dependent cellular phagocytic activity. This simple formula incorporates only the antibody and PMPC without requiring additional components, thereby addressing the issues of the nanocapsule platform and paving the way for PMPC-based brain delivery strategies for antibodies.

10.
Front Immunol ; 13: 877682, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35967430

RESUMO

Chimeric-antigen receptor (CAR) T-cell immunotherapy employs autologous-T cells modified with an antigen-specific CAR. Current CAR-T manufacturing processes tend to yield products dominated by effector T cells and relatively small proportions of long-lived memory T cells. Those few cells are a so-called stem cell memory T (TSCM) subset, which express naïve T-cell markers and are capable of self-renewal and oligopotent differentiation into effector phenotypes. Increasing the proportion of this subset may lead to more effective therapies by improving CAR-T persistence; however, there is currently no standardized protocol for the effective generation of CAR-TSCM cells. Here we present a simplified protocol enabling efficient derivation of gene-modified TSCM cells: Stimulation of naïve CD8+ T cells with only soluble anti-CD3 antibody and culture with IL-7 and IL-15 was sufficient for derivation of CD8+ T cells harboring TSCM phenotypes and oligopotent capabilities. These in-vitro expanded TSCM cells were engineered with CARs targeting the HIV-1 envelope protein as well as the CD19 molecule and demonstrated effector activity both in vitro and in a xenograft mouse model. This simple protocol for the derivation of CAR-TSCM cells may facilitate improved adoptive immunotherapy.


Assuntos
Receptores de Antígenos Quiméricos , Animais , Antígenos CD19/metabolismo , Linfócitos T CD8-Positivos , Humanos , Imunoterapia Adotiva/métodos , Camundongos , Receptores de Antígenos de Linfócitos T , Receptores de Antígenos Quiméricos/genética
11.
iScience ; 25(12): 105544, 2022 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-36406860

RESUMO

Umbilical cord blood (UCB) is an irreplaceable source for hematopoietic stem progenitor cells (HSPCs). However, the effects of SARS-CoV-2 infection and COVID-19 vaccination on UCB phenotype, specifically the HSPCs therein, are currently unknown. We thus evaluated any effects of SARS-CoV-2 infection and/or COVID-19 vaccination from the mother on the fate and functionalities of HSPCs in the UCB. The numbers and frequencies of HSPCs in the UCB decreased significantly in donors with previous SARS-CoV-2 infection and more so with COVID-19 vaccination via the induction of apoptosis, likely mediated by IFN-γ-dependent pathways. Two independent hematopoiesis assays, a colony forming unit assay and a mouse humanization assay, revealed skewed hematopoiesis of HSPCs obtained from donors delivered from mothers with SARS-CoV-2 infection history. These results indicate that SARS-CoV-2 infection and COVID-19 vaccination impair the functionalities and survivability of HSPCs in the UCB, which would make unprecedented concerns on the future of HSPC-based therapies.

12.
PLoS Pathog ; 5(3): e1000342, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19300495

RESUMO

HIV-1 is restricted for infection of primary quiescent T-cells. After viral entry, reverse transcription is initiated but is not completed. Various hypotheses have been proposed for this cellular restriction including insufficient nucleotide pools and cellular factors, but none have been confirmed as the primary mechanism for restriction. A recent study by Chiu et al. implicates APOBEC3G, an anti-retroviral cytidine deaminase, as the cellular restriction factor. Here, we attempted to confirm these findings using the same strategy as reported by Chiu et al. of siRNA targeting knock-down of APOBEC3G expression. In contrast to the published study, our results do not support a role for APOBEC3G in restriction of HIV-1 in quiescent CD4+ T-cells. In our study, we tested the same siRNA as reported by Chiu et al. as well as two additional siRNAs targeting APOBEC3G, one of which showed 2-fold greater knock-down of APOBEC3G mRNA. However, none of the three siRNAs tested had a discernable effect on enhancing infection by HIV-1 in quiescent CD4+ T-cells. Therefore, we conclude that the primary mechanism of HIV-1 restriction in quiescent CD4+ T-cells remains to be elucidated.


Assuntos
Linfócitos T CD4-Positivos/virologia , Citidina Desaminase/genética , Infecções por HIV/genética , HIV-1/fisiologia , HIV-1/patogenicidade , Desaminase APOBEC-3G , Western Blotting , Citidina Desaminase/metabolismo , Citometria de Fluxo , Infecções por HIV/metabolismo , Humanos , RNA Interferente Pequeno , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transcrição Reversa , Transdução Genética
13.
J Immunother Cancer ; 9(2)2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33593826

RESUMO

BACKGROUND: Despite the numerous applications of monoclonal antibodies (mAbs) in cancer therapeutics, animal models available to test the therapeutic efficacy of new mAbs are limited. NOD.Cg-Prkdcscid Il2rg tm1Wjl /SzJ (NSG) mice are one of the most highly immunodeficient strains and are universally used as a model for testing cancer-targeting mAbs. However, this strain lacks several factors necessary to fully support antibody-mediated effector functions-including antibody-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis, and complement-dependent cytotoxicity (CDC)-due to the absence of immune cells as well as a mutation in the Hc gene, which is needed for a functional complement system. METHODS: We have developed a humanized mouse model using a novel NSG strain, NOD.Cg-Hc1Prkdcscid Il2rgtm1Wjl/SzJ (NSG-Hc1), which contains the corrected mutation in the Hc gene to support CDC in addition to other mechanisms endowed by humanization. With this model, we reevaluated the anticancer efficacies of nanoencapsulated rituximab after xenograft of the human Burkitt lymphoma cell line 2F7-BR44. RESULTS: As expected, xenografted humanized NSG-Hc1 mice supported superior lymphoma clearance of native rituximab compared with the parental NSG strain. Nanoencapsulated rituximab with CXCL13 conjugation as a targeting ligand for lymphomas further enhanced antilymphoma activity in NSG-Hc1 mice and, more importantly, mediated antilymphoma cellular responses. CONCLUSIONS: These results indicate that NSG-Hc1 mice can serve as a feasible model for both studying antitumor treatment using cancer targeting as well as understanding induction mechanisms of antitumor cellular immune response.


Assuntos
Linfoma de Burkitt/tratamento farmacológico , Quimiocinas CXC/química , Rituximab/administração & dosagem , Animais , Linfoma de Burkitt/genética , Linfoma de Burkitt/imunologia , Linhagem Celular Tumoral , Humanos , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Camundongos Transgênicos , Nanocápsulas , Metástase Neoplásica , Rituximab/química , Rituximab/farmacologia , Resultado do Tratamento , Ensaios Antitumorais Modelo de Xenoenxerto
14.
J Gene Med ; 12(3): 255-65, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20186995

RESUMO

BACKGROUND: We recently expressed a potent and noncytotoxic short hairpin (sh)RNA directed against chemokine (c-c motif) receptor 5 (CCR5) using lentiviral mediated transduction of CD34+ hematopoietic progenitor cells (HPCs) and demonstrated the stable reduction of CCR5 expression in T-lymphocytes. METHODS: In the present study, we further assessed the activity of the shRNA through HPC transduction and differentiation into macrophages derived from fetal liver CD34+ (FL-CD34+) HPCs. Transduced lentiviral vector encoding the human CCR5 shRNA was stably maintained in FL-CD34+ cells and in the terminally differentiated macrophages using macrophage colony-stimulating factor, granulocyte macrophage colony-stimulating factor, interleukin-3 and stem cell factor. RESULTS: Quantitative real-time polymerase chain reaction for CCR5 mRNA indicated over 90% reduction of CCR5 mRNA levels in CCR5 shRNA-transduced population. The cells with knockdown of CCR5 expression acquired resistance to R5 tropic HIV-1 NFN-SX strain. We also developed a novel approach utilizing a mCherry-CCR5 chimeric reporter to assess the effectiveness of CCR5 target down-regulation in macrophages directly. Both the shRNA and the reporter were maintained throughout HPC differentiation to macrophages without apparent cytotoxicity. CONCLUSIONS: The present study demonstrates a novel method to simply and directly assess the function of small interfering RNA and the effective inhibition of HIV-1 infection by a potential potent shRNA to CCR5 delivered into macrophages derived from HPCs.


Assuntos
Antagonistas dos Receptores CCR5 , Terapia Genética/métodos , Infecções por HIV/prevenção & controle , HIV-1 , RNA Interferente Pequeno/genética , Linhagem Celular , Técnicas de Silenciamento de Genes , Células-Tronco Hematopoéticas/fisiologia , Humanos , Macrófagos/fisiologia , Receptores CCR5/genética , Transdução Genética
15.
J Virol ; 83(21): 11283-97, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19692467

RESUMO

Human immunodeficiency virus type 1 (HIV-1) Vpr protein exists in three different forms: soluble, intracellular, and virion associated. Previous studies showed that virion-associated Vpr induces apoptosis in activated peripheral blood mononuclear cells (PBMCs) and Jurkat T cells, but these studies were conducted in the presence of other de novo-expressed HIV proteins that may have had additive proapoptotic effects. In this report, we show that virion-associated Vpr triggers apoptosis through caspases 3/7 and 9 in human T cells independently of other HIV de novo-expressed proteins. In contrast to a previous study, we also detected the activation of caspase 8, the initiator caspase of the death receptor pathway. However, activation of all caspases by virion-associated Vpr was independent of the Fas death receptor pathway. Further analyses showed that virion-associated Vpr enhanced caspase activation in Fas-mediated apoptosis in Jurkat T cells and human activated PBMCs. Thus, our results indicate for the first time that viral particles that contain virion-associated Vpr can cause apoptosis in the absence of other de novo-expressed viral factors and can act in synergy with the Fas receptor pathway, thereby enhancing the apoptotic process in T cells. These findings suggest that virion-associated Vpr can contribute to the depletion of CD4(+) lymphocytes either directly or by enhancing Fas-mediated apoptosis during acute HIV-1 infection and in AIDS.


Assuntos
Apoptose/imunologia , HIV-1/imunologia , Linfócitos T/imunologia , Vírion/metabolismo , Receptor fas/imunologia , Produtos do Gene vpr do Vírus da Imunodeficiência Humana/imunologia , Animais , Caspases/metabolismo , Ciclo Celular/fisiologia , Linhagem Celular , Ativação Enzimática , Infecções por HIV/imunologia , Humanos , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/imunologia , Linfócitos T/citologia , Produtos do Gene vpr do Vírus da Imunodeficiência Humana/genética
16.
J Virol ; 83(24): 13026-31, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19793825

RESUMO

We recently developed a novel targeting Sindbis virus envelope pseudotyped lentiviral vector, 2.2ZZ, which acquires specific transduction capacity by antibody conjugation and binding with specific antigens on the surface of targeted cells. Here we characterize the virological properties of this vector by examining its targeting to CD4 antigen. Our results show that entry is dependent on CD4 cell surface density and occurs via the clathrin-mediated endocytic pathway. These findings provide insight into the mechanism of infection by a new viral vector with combined properties of Sindbis virus and lentiviruses and infectivity conferred by monoclonal antibody-ligand interactions.


Assuntos
Antígenos CD4/fisiologia , Clatrina/fisiologia , Endocitose , Vetores Genéticos/genética , Lentivirus/genética , Transdução Genética , Humanos
17.
J Gene Med ; 11(2): 103-11, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19065606

RESUMO

BACKGROUND: The transthyretin (TTR) amyloidosis is an incurable fatal inherited disease that is characterized by progressive peripheral and autonomic neuropathy. It is caused by missense amyloidogenic mutations in the TTR gene that destabilize the native tetrameric state and lead to the cytotoxic misfolded monomeric state. One interesting variant (T119M) stabilizes heterotetramers with amyloidogenic TTR and, in the reported heterozygous individuals, protects the carriers from disease. In the present study, we characterize in vitro and in vivo the ectopic expression of the human T119M mutant, termed a transsuppressor for TTR amyloid disease. METHODS: Lentiviral vectors encoding wild or mutant forms of human TTR were constructed and transduced to the human hepatocellular carcinoma cell line, HepG2, or mice. Heterooligomerization between T119M TTR and amyloidogenic variants was analysed by immunoprecipitation following western blotting. RESULTS: T119M TTR was stably expressed in transduced HepG2 cells and was secreted as an oligomer that can interact with its native partner, retinol-binding protein. Importantly, the T119M TTR formed secreted heterooligomers with amyloidogenic TTR variants, V30M, L55P and V122I, in HepG2 cells that were more stable than the homooligomers of the same amyloidogenic TTR variants. Human T119M TTR also formed heterooligomers with V30M TTR in transduced mice. CONCLUSIONS: The results obtained in the present study demonstrate the stabilization of heterotetramers by T119M TTR in human cells and suggest that gene transfer of T119M TTR may have potential as a gene therapy for TTR amyloidosis.


Assuntos
Amiloidose/genética , Pré-Albumina/genética , Pré-Albumina/metabolismo , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Vetores Genéticos/genética , Vetores Genéticos/metabolismo , Humanos , Lentivirus/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Camundongos , Mutação
18.
J Virol ; 82(12): 5672-82, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18385244

RESUMO

Human immunodeficiency virus type 1 Vpr is a virion-associated accessory protein that has multiple activities within an infected cell. One of the most dramatic effects of Vpr is the induction of cell cycle arrest at the G(2)/M boundary, followed by apoptosis. This effect has implications for CD4(+) cell loss in AIDS. In normal cell cycle regulation, Wee1, a key regulator for G(2)-M progression, phosphorylates Tyr15 on Cdc2 and thereby blocks the progression of cells into M phase. We demonstrate that Vpr physically interacts with Wee1 at the N lobe of the kinase domain analogous to that present in other kinases. This interaction with Vpr enhances Wee1 kinase activity for Cdc2. Overexpression of Wee1 kinase-deficient mutants competes for Vpr-mediated cell cycle arrest, and deletion of the region of Wee1 that binds Vpr abrogates that competition. However, the Vpr mutants I74P and I81P, which fail to induce G(2) arrest, can bind to and increase the kinase activity of Wee1 to the same extent as wild-type Vpr. Therefore, we conclude that the binding of Vpr to Wee1 is not sufficient for Vpr to activate the G(2) checkpoint, and it may reflect an independent function of Vpr.


Assuntos
Proteína Quinase CDC2/fisiologia , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Produtos do Gene vpr/metabolismo , HIV-1 , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Proteínas Tirosina Quinases/química , Proteínas Tirosina Quinases/metabolismo , Proteína Quinase CDC2/isolamento & purificação , Proteínas de Ciclo Celular/análise , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/isolamento & purificação , Linhagem Celular , Fase G2 , Produtos do Gene vpr/genética , Glutationa Transferase/metabolismo , Células HeLa , Humanos , Rim/citologia , Proteínas Nucleares/análise , Proteínas Nucleares/genética , Proteínas Nucleares/isolamento & purificação , Plasmídeos , Estrutura Terciária de Proteína , Proteínas Tirosina Quinases/análise , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/isolamento & purificação , Proteínas Recombinantes de Fusão/metabolismo , Transfecção
19.
Genet Vaccines Ther ; 7: 8, 2009 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-19515239

RESUMO

BACKGROUND: The use of shRNAs to downregulate the expression of specific genes is now relatively routine in experimentation but still hypothetical for clinical application. A potential therapeutic approach for HIV-1 disease is shRNA mediated downregulation of the HIV-1 co-receptor, CCR5. It is increasingly recognized that siRNAs and shRNAs can have unintended consequences such as cytotoxicities in cells, particularly when used for long term therapeutic purposes. For the clinical use of shRNAs, it is crucial to identify a shRNA that can potently inhibit CCR5 expression without inducing unintended cytotoxicities. RESULTS: Previous shRNAs to CCR5 identified using conventional commercial algorithms showed cytotoxicity when expressed using the highly active U6 pol III promoter in primary human peripheral blood derived mononuclear cells. Expression using the lower activity H1 promoter significantly reduced toxicity, but all shRNAs also reduced RNAi activity. In an effort to identify shRNAs that were both potent and non-cytotoxic, we created a shRNA library representing all potential CCR5 20 to 22-nucleotide shRNA sequences expressed using an H1 promoter and screened this library for downregulation of CCR5. We identified one potent CCR5 shRNA that was also non-cytotoxic when expressed at a low level with the H1 promoter. We characterized this shRNA in regards to its function and structure. This shRNA was unique that the use of commercial and published algorithms to predict effective siRNA sequences did not result in identification of the same shRNA. We found that this shRNA could induce sequence specific reduction of CCR5 at post transcriptional level, consistent with the RNA interference mechanism. Importantly, this shRNA showed no obvious cytotoxicity and was effective at downregulating CCR5 in primary human peripheral blood derived mononuclear cells. CONCLUSION: We report on the characterization of a rare shRNA with atypical structural features having potent RNAi activity specific to CCR5. These results have implications for the application of RNAi technology for therapeutic purposes.

20.
Nat Biomed Eng ; 3(9): 706-716, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31384008

RESUMO

Approximately 15-40% of all cancers develop metastases in the central nervous system (CNS), yet few therapeutic options exist to treat them. Cancer therapies based on monoclonal antibodies are widely successful, yet have limited efficacy against CNS metastases, owing to the low levels of the drug reaching the tumour site. Here, we show that the encapsulation of rituximab within a crosslinked zwitterionic polymer layer leads to the sustained release of rituximab as the crosslinkers are gradually hydrolysed, enhancing the CNS levels of the antibody by approximately tenfold with respect to the administration of naked rituximab. When the nanocapsules were functionalized with CXCL13-the ligand for the chemokine receptor CXCR5, which is frequently found on B-cell lymphoma-a single dose led to improved control of CXCR5-expressing metastases in a murine xenograft model of non-Hodgkin lymphoma, and eliminated lymphoma in a xenografted humanized bone marrow-liver-thymus mouse model. Encapsulation and molecular targeting of therapeutic antibodies could become an option for the treatment of cancers with CNS metastases.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Sistema Nervoso Central , Sistemas de Liberação de Medicamentos/métodos , Linfoma de Células B/tratamento farmacológico , Terapia de Alvo Molecular/métodos , Rituximab/farmacologia , Animais , Encéfalo , Quimiocina CXCL13/efeitos dos fármacos , Quimiocina CXCL13/metabolismo , Modelos Animais de Doenças , Metástase Linfática/tratamento farmacológico , Linfoma não Hodgkin/tratamento farmacológico , Camundongos , Nanocápsulas , Receptores CXCR5/efeitos dos fármacos , Receptores CXCR5/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
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