RESUMO
Intestinal commensal bacteria can inhibit dense colonization of the gut by vancomycin-resistant Enterococcus faecium (VRE), a leading cause of hospital-acquired infections1,2. A four-strained consortium of commensal bacteria that contains Blautia producta BPSCSK can reverse antibiotic-induced susceptibility to VRE infection3. Here we show that BPSCSK reduces growth of VRE by secreting a lantibiotic that is similar to the nisin-A produced by Lactococcus lactis. Although the growth of VRE is inhibited by BPSCSK and L. lactis in vitro, only BPSCSK colonizes the colon and reduces VRE density in vivo. In comparison to nisin-A, the BPSCSK lantibiotic has reduced activity against intestinal commensal bacteria. In patients at high risk of VRE infection, high abundance of the lantibiotic gene is associated with reduced density of E. faecium. In germ-free mice transplanted with patient-derived faeces, resistance to VRE colonization correlates with abundance of the lantibiotic gene. Lantibiotic-producing commensal strains of the gastrointestinal tract reduce colonization by VRE and represent potential probiotic agents to re-establish resistance to VRE.
Assuntos
Bacteriocinas/metabolismo , Bacteriocinas/farmacologia , Enterococcus faecium/efeitos dos fármacos , Lactococcus lactis/metabolismo , Probióticos , Resistência a Vancomicina/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Animais , Antibacterianos/biossíntese , Antibacterianos/isolamento & purificação , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Bacteriocinas/genética , Bacteriocinas/isolamento & purificação , Enterococcus faecium/crescimento & desenvolvimento , Enterococcus faecium/isolamento & purificação , Fezes/microbiologia , Feminino , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/microbiologia , Vida Livre de Germes , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/crescimento & desenvolvimento , Humanos , Lactococcus lactis/química , Lactococcus lactis/crescimento & desenvolvimento , Lactococcus lactis/fisiologia , Camundongos , Testes de Sensibilidade Microbiana , Microbiota/genética , Nisina/química , Nisina/farmacologia , Simbiose/efeitos dos fármacos , Vancomicina/farmacologia , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Enterococos Resistentes à Vancomicina/isolamento & purificaçãoRESUMO
The human gastrointestinal tract hosts a diverse network of microorganisms, collectively known as the microbiota that plays an important role in health and disease. For instance, the intestinal microbiota can prevent invading microbes from colonizing the gastrointestinal tract, a phenomenon known as colonization resistance. Perturbations to the microbiota, such as antibiotic administration, can alter microbial composition and result in the loss of colonization resistance. Consequently, the host may be rendered susceptible to colonization by a pathogen. This is a particularly relevant concern in the hospital setting, where antibiotic use and antibiotic-resistant pathogen exposure are more frequent. Many nosocomial infections arise from gastrointestinal colonization. Due to their resistance to antibiotics, treatment is often very challenging. However, recent studies have demonstrated that manipulating the commensal microbiota can prevent and treat various infections in the intestine. In this review, we discuss the members of the microbiota, as well as the mechanisms, that govern colonization resistance against specific pathogens. We also review the effects of antibiotics on the microbiota, as well as the unique epidemiology of immunocompromised patients that renders them a particularly high-risk population to intestinal nosocomial infections.
Assuntos
Antibacterianos/uso terapêutico , Infecções Bacterianas/imunologia , Infecção Hospitalar/imunologia , Microbioma Gastrointestinal/imunologia , Animais , Antibacterianos/efeitos adversos , Infecções Bacterianas/microbiologia , Infecção Hospitalar/microbiologia , Resistência a Medicamentos , Disbiose/etiologia , Interações Hospedeiro-Patógeno , Humanos , Hospedeiro ImunocomprometidoRESUMO
HIV infection has been associated with defective hematopoiesis since the earliest days of the HIV/AIDS epidemic. Generation of all hematopoietic lineages suffers in the face of infection. The mechanisms by which HIV impairs normal blood cell development remain unclear, and direct infection of intermediate hematopoietic progenitors has not been established as a source of HIV-associated hematopoietic pathology. Here, we demonstrate infection of multiple subsets of highly purified intermediate hematopoietic progenitors by wild-type HIV both in vitro and in vivo. Although direct infection is clearly cytotoxic, we find that some infected progenitors can survive and harbor proviral DNA. We report intermediate hematopoietic progenitors to be a novel target of infection and their permissivity to infection increases with development. Further, the nonobese diabetic severe combined immunodeficiency common γ chain knockout-bone marrow-liver-thymus humanized mouse provides a unique model for studying the impact of HIV infection on bone marrow-based human hematopoiesis.
Assuntos
Infecções por HIV/patologia , HIV-1/imunologia , Células-Tronco Hematopoéticas/virologia , Animais , DNA Viral , Modelos Animais de Doenças , Citometria de Fluxo , Infecções por HIV/imunologia , Hematopoese/imunologia , Humanos , Camundongos , Reação em Cadeia da Polimerase em Tempo RealRESUMO
The HIV-specific cytotoxic T lymphocyte (CTL) response is a critical component in controlling viral replication in vivo, but ultimately fails in its ability to eradicate the virus. Our intent in these studies is to develop ways to enhance and restore the HIV-specific CTL response to allow long-term viral suppression or viral clearance. In our approach, we sought to genetically manipulate human hematopoietic stem cells (HSCs) such that they differentiate into mature CTL that will kill HIV infected cells. To perform this, we molecularly cloned an HIV-specific T cell receptor (TCR) from CD8+ T cells that specifically targets an epitope of the HIV-1 Gag protein. This TCR was then used to genetically transduce HSCs. These HSCs were then introduced into a humanized mouse containing human fetal liver, fetal thymus, and hematopoietic progenitor cells, and were allowed to differentiate into mature human CD8+ CTL. We found human, HIV-specific CTL in multiple tissues in the mouse. Thus, genetic modification of human HSCs with a cloned TCR allows proper differentiation of the cells to occur in vivo, and these cells migrate to multiple anatomic sites, mimicking what is seen in humans. To determine if the presence of the transgenic, HIV-specific TCR has an effect on suppressing HIV replication, we infected with HIV-1 mice expressing the transgenic HIV-specific TCR and, separately, mice expressing a non-specific control TCR. We observed significant suppression of HIV replication in multiple organs in the mice expressing the HIV-specific TCR as compared to control, indicating that the presence of genetically modified HIV-specific CTL can form a functional antiviral response in vivo. These results strongly suggest that stem cell based gene therapy may be a feasible approach in the treatment of chronic viral infections and provide a foundation towards the development of this type of strategy.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Engenharia Celular , Terapia Genética , Proteína do Núcleo p24 do HIV/imunologia , Infecções por HIV/terapia , HIV-1/fisiologia , Células-Tronco Hematopoéticas/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Replicação Viral/fisiologia , Animais , Linfócitos T CD8-Positivos/metabolismo , Feminino , Proteína do Núcleo p24 do HIV/genética , Proteína do Núcleo p24 do HIV/metabolismo , Infecções por HIV/genética , Infecções por HIV/imunologia , Infecções por HIV/metabolismo , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/metabolismo , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Transplante HeterólogoRESUMO
Current tumor immunotherapy approaches include the genetic modification of peripheral T cells to express tumor antigen-specific T-cell receptors (TCRs). The approach, tested in melanoma, has led to some limited success of tumor regression in patients. Yet, the introduction of exogenous TCRs into mature T cells entails an underlying risk; the generation of autoreactive clones due to potential TCR mispairing, and the lack of effective negative selection, as these peripheral cells do not undergo thymic selection following introduction of the exogenous TCR. We have successfully generated MART-1-specific CD8 T cells from genetically modified human hematopoietic stem cells (hHSC) in a humanized mouse model. The advantages of this approach include a long-term source of antigen specific T cells and proper T-cell selection due to thymopoiesis following expression of the TCR. In this report, we examine the molecular processes occurring on endogenous TCR expression and demonstrate that this approach results in exclusive cell surface expression of the newly introduced TCR, and the exclusion of endogenous TCR cell surface expression. This suggests that this stem cell based approach can provide a potentially safer approach for anticancer immunotherapy due to the involvement of thymic selection.
Assuntos
Regulação da Expressão Gênica , Células-Tronco Hematopoéticas/metabolismo , Receptores de Antígenos de Linfócitos T/genética , Animais , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Diferenciação Celular/imunologia , Seleção Clonal Mediada por Antígeno/imunologia , Expressão Gênica , Rearranjo Gênico do Linfócito T , Células-Tronco Hematopoéticas/citologia , Humanos , Implantes Experimentais , Camundongos , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Linfócitos T/citologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , TransgenesRESUMO
The goal of cancer immunotherapy is the generation of an effective, stable, and self-renewing antitumor T-cell population. One such approach involves the use of high-affinity cancer-specific T-cell receptors in gene-therapy protocols. Here, we present the generation of functional tumor-specific human T cells in vivo from genetically modified human hematopoietic stem cells (hHSC) using a human/mouse chimera model. Transduced hHSC expressing an HLA-A*0201-restricted melanoma-specific T-cell receptor were introduced into humanized mice, resulting in the generation of a sizeable melanoma-specific naïve CD8(+) T-cell population. Following tumor challenge, these transgenic CD8(+) T cells, in the absence of additional manipulation, limited and cleared human melanoma tumors in vivo. Furthermore, the genetically enhanced T cells underwent proper thymic selection, because we did not observe any responses against non-HLA-matched tumors, and no killing of any kind occurred in the absence of a human thymus. Finally, the transduced hHSC established long-term bone marrow engraftment. These studies present a potential therapeutic approach and an important tool to understand better and to optimize the human immune response to melanoma and, potentially, to other types of cancer.
Assuntos
Antineoplásicos/farmacologia , Linfócitos T CD8-Positivos/citologia , Células-Tronco Hematopoéticas/citologia , Animais , Antígenos CD34/biossíntese , Linfócitos T CD8-Positivos/imunologia , Linhagem Celular Tumoral , Citometria de Fluxo/métodos , Engenharia Genética/métodos , Humanos , Imunoterapia/métodos , Linfócitos do Interstício Tumoral/citologia , Camundongos , Camundongos SCID , Modelos Genéticos , Transplante de Neoplasias , Células-Tronco/citologia , Timo/metabolismo , TransgenesRESUMO
Carbapenem-resistant Klebsiella pneumoniae (CR-Kp) is a significant threat to public health worldwide. The primary reservoir for CR-Kp is the intestinal tract. There, the bacterium is usually present at low density but can bloom following antibiotic treatment, mostly in hospital settings. The impact of disturbances in the intestinal environment on the fitness, survival, expansion, and drug susceptibility of this pathogen is not well-understood, yet it may be relevant to devise strategies to tackle CR-Kp colonization and infection. Here, we adopted an in vivo model to examine the transcriptional adaptation of a CR-Kp clinical isolate to immune activation in the intestine. We report that as early as 6 hours following host treatment with anti-CD3 antibody, CR-Kp underwent rapid transcriptional changes including downregulation of genes involved in sugar utilization and amino acid biosynthesis and upregulation of genes involved in amino acid uptake and catabolism, antibiotic resistance, and stress response. In agreement with these findings, treatment increased the concentration of oxidative species and amino acids in the mouse intestine. Genes encoding for proteins containing the domain of unknown function (DUF) 1471 were strongly upregulated, however their deletion did not impair CR-Kp fitness in vivo upon immune activation. Transcription factor enrichment analysis identified the global regulator cAMP-Receptor Protein, CRP, as a potential orchestrator of the observed transcriptional signature. In keeping with the recognized role of CRP in regulating utilization of alternative carbon sources, crp deletion in CR-Kp resulted in strongly impaired gut colonization, although this effect was not amplified by immune activation. Thus, following intestinal colonization, which occurs in a CRP-dependent manner, CR-Kp can rapidly respond to immune cues by implementing a well-defined and complex transcriptional program whose direct relevance toward bacterial fitness warrants further investigation. Additional analyses utilizing this model may identify key factors to tackle CR-Kp colonization of the intestine.
Assuntos
Antibacterianos , Intestinos , Infecções por Klebsiella , Klebsiella pneumoniae , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/imunologia , Animais , Camundongos , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/imunologia , Intestinos/microbiologia , Intestinos/imunologia , Antibacterianos/farmacologia , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Regulação Bacteriana da Expressão Gênica , Carbapenêmicos/farmacologia , Camundongos Endogâmicos C57BL , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Feminino , HumanosRESUMO
The restriction of the Human Immunodeficiency Virus (HIV) infection in quiescent CD4⺠T cells has been an area of active investigation. Early studies have suggested that this T cell subset is refractory to infection by the virus. Subsequently it was demonstrated that quiescent cells could be infected at low levels; nevertheless these observations supported the earlier assertions of debilitating defects in the viral life cycle. This phenomenon raised hopes that identification of the block in quiescent cells could lead to the development of new therapies against HIV. As limiting levels of raw cellular factors such as nucleotides did not account for the block to infection, a number of groups pursued the identification of cellular proteins whose presence or absence may impact the permissiveness of quiescent T cells to HIV infection. A series of studies in the past few years have identified a number of host factors implicated in the block to infection. In this review, we will present the progress made, other avenues of investigation and the potential impact these studies have in the development of more effective therapies against HIV.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/virologia , Infecções por HIV/imunologia , Infecções por HIV/virologia , HIV/imunologia , Replicação Viral , HumanosRESUMO
The gut microbiota produces metabolites that regulate host immunity, thereby impacting disease resistance and susceptibility. The extent to which commensal bacteria reciprocally respond to immune activation, however, remains largely unexplored. Herein, we colonized mice with four anaerobic symbionts and show that acute immune responses result in dramatic transcriptional reprogramming of these commensals with minimal changes in their relative abundance. Transcriptomic changes include induction of stress-response mediators and downregulation of carbohydrate-degrading factors such as polysaccharide utilization loci (PULs). Flagellin and anti-CD3 antibody, two distinct immune stimuli, induced similar transcriptional profiles, suggesting that commensal bacteria detect common effectors or activate shared pathways when facing different host responses. Immune activation altered the intestinal metabolome within 6 hours, decreasing luminal short-chain fatty acid and increasing aromatic metabolite concentrations. Thus, intestinal bacteria, prior to detectable shifts in community composition, respond to acute host immune activation by rapidly changing gene transcription and immunomodulatory metabolite production.
Assuntos
Microbioma Gastrointestinal/imunologia , Microbioma Gastrointestinal/fisiologia , Intestinos/imunologia , Intestinos/microbiologia , Animais , Bactérias/genética , Bactérias/metabolismo , Estudos Transversais , Regulação para Baixo , Ácidos Graxos Voláteis , Feminino , Flagelina , Microbioma Gastrointestinal/genética , Inflamação/imunologia , Metaboloma , Camundongos , Camundongos Endogâmicos C57BL , RNA Ribossômico 16S , Simbiose , TranscriptomaRESUMO
BACKGROUND: Monocytes are an essential cellular component of the innate immune system that support the host's effectiveness to combat a range of infectious pathogens. Hemopoietic cell transplantation (HCT) results in transient monocyte depletion, but the factors that regulate recovery of monocyte populations are not fully understood. In this study, we investigated whether the composition of the gastrointestinal microbiota is associated with the recovery of monocyte homeostasis after HCT. METHODS: We performed a single-center, prospective, pilot study of 18 recipients of either autologous or allogeneic HCT. Serial blood and stool samples were collected from each patient during their HCT hospitalization. Analysis of the gut microbiota was done using 16S rRNA gene sequencing, and flow cytometric analysis was used to characterize the phenotypic composition of monocyte populations. RESULTS: Dynamic fluctuations in monocyte reconstitution occurred after HCT, and large differences were observed in monocyte frequency among patients over time. Recovery of absolute monocyte counts and subsets showed significant variability across the heterogeneous transplant types and conditioning intensities; no relationship to the microbiota composition was observed in this small cohort. CONCLUSION: In this pilot study, a relationship between the microbiota composition and monocyte homeostasis could not be firmly established. However, we identify multivariate associations between clinical factors and monocyte reconstitution post-HCT. Our findings encourage further longitudinal surveillance of the intestinal microbiome and its link to immune reconstitution.
RESUMO
Listeria monocytogenes is a foodborne pathogen that causes septicemia, meningitis and chorioamnionitis and is associated with high mortality. Immunocompetent humans and animals, however, can tolerate high doses of L. monocytogenes without developing systemic disease. The intestinal microbiota provides colonization resistance against many orally acquired pathogens, and antibiotic-mediated depletion of the microbiota reduces host resistance to infection. Here we show that a diverse microbiota markedly reduces Listeria monocytogenes colonization of the gut lumen and prevents systemic dissemination. Antibiotic administration to mice before low dose oral inoculation increases L. monocytogenes growth in the intestine. In immunodeficient or chemotherapy-treated mice, the intestinal microbiota provides nonredundant defense against lethal, disseminated infection. We have assembled a consortium of commensal bacteria belonging to the Clostridiales order, which exerts in vitro antilisterial activity and confers in vivo resistance upon transfer into germ free mice. Thus, we demonstrate a defensive role of the gut microbiota against Listeria monocytogenes infection and identify intestinal commensal species that, by enhancing resistance against this pathogen, represent potential probiotics.
Assuntos
Microbioma Gastrointestinal/fisiologia , Intestinos/microbiologia , Listeria monocytogenes/fisiologia , Listeriose/microbiologia , Animais , Antibacterianos/administração & dosagem , Antibacterianos/farmacologia , Antibiose/efeitos dos fármacos , Fezes/microbiologia , Interações Hospedeiro-Patógeno/genética , Humanos , Hospedeiro Imunocomprometido , Intestinos/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos , Listeriose/genética , Listeriose/mortalidade , Camundongos Endogâmicos C57BL , Camundongos Knockout , Análise de Sobrevida , Taxa de Sobrevida , Fatores de TempoRESUMO
Antibiotic-mediated microbiota destruction and the consequent loss of colonization resistance can result in intestinal domination with vancomycin-resistant Enterococcus (VRE), leading to bloodstream infection in hospitalized patients. Clearance of VRE remains a challenging goal that, if achieved, would reduce systemic VRE infections and patient-to-patient transmission. Although obligate anaerobic commensal bacteria have been associated with colonization resistance to VRE, the specific bacterial species involved remain undefined. Herein, we demonstrate that a precisely defined consortium of commensal bacteria containing the Clostridium cluster XIVa species Blautia producta and Clostridium bolteae restores colonization resistance against VRE and clears VRE from the intestines of mice. While C. bolteae did not directly mediate VRE clearance, it enabled intestinal colonization with B. producta, which directly inhibited VRE growth. These findings suggest that therapeutic or prophylactic administration of defined bacterial consortia to individuals with compromised microbiota composition may reduce inter-patient transmission and intra-patient dissemination of highly antibiotic-resistant pathogens.
Assuntos
Enterococcus faecium/crescimento & desenvolvimento , Microbiota/fisiologia , Simbiose/fisiologia , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Ampicilina/farmacologia , Animais , Antibacterianos/farmacologia , Bactérias/genética , Bactérias/isolamento & purificação , Fenômenos Fisiológicos Bacterianos , Clostridium/fisiologia , Contagem de Colônia Microbiana , DNA Bacteriano , Farmacorresistência Bacteriana , Enterococcus faecium/patogenicidade , Fezes/microbiologia , Feminino , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Bactérias Gram-Positivas/prevenção & controle , Intestinos/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , RNA Ribossômico 16S/genética , Vancomicina/farmacologia , Enterococos Resistentes à Vancomicina/genética , Enterococos Resistentes à Vancomicina/patogenicidadeRESUMO
Cocaine abuse has been shown to have broad-ranging effects on human immunity. With regards to HIV infection, in vitro studies have shown that cocaine enhances infection of stimulated lymphocytes. Moreover, cohort studies in the pre- and post-HAART era have linked stimulant abuse with increased HIV pathogenesis. The latter data, however, have been undermined by a series of confounding factors underscoring the importance of controlled in vivo models to fully assess the impact of cocaine use and abuse on HIV infection and pathogenesis. Here, we have infected humanized mice with HIV-1 following acute cocaine exposure to assess the impact on infection. Stimulant exposure resulted in increased inflammatory cytokine expression, accelerated HIV infection, while blunting effector function of cytotoxic T lymphocytes. These data demonstrate cocaine's multifactorial impact on HIV infection that extends beyond high-risk behavior.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Cocaína/efeitos adversos , Citocinas/imunologia , Regulação da Expressão Gênica/efeitos dos fármacos , Infecções por HIV/imunologia , HIV-1/imunologia , Animais , Linfócitos T CD8-Positivos/patologia , Cocaína/farmacologia , Modelos Animais de Doenças , Regulação da Expressão Gênica/imunologia , Infecções por HIV/patologia , Humanos , CamundongosRESUMO
We described earlier a dual-combination anti-HIV type 1 (HIV-1) lentiviral vector (LVsh5/C46) that downregulates CCR5 expression of transduced cells via RNAi and inhibits HIV-1 fusion via cell surface expression of cell membrane-anchored C46 antiviral peptide. This combinatorial approach has two points of inhibition for R5-tropic HIV-1 and is also active against X4-tropic HIV-1. Here, we utilize the humanized bone marrow, liver, thymus (BLT) mouse model to characterize the in vivo efficacy of LVsh5/C46 (Cal-1) vector to engineer cellular resistance to HIV-1 pathogenesis. Human CD34+ hematopoietic stem/progenitor cells (HSPC) either nonmodified or transduced with LVsh5/C46 vector were transplanted to generate control and treatment groups, respectively. Control and experimental groups displayed similar engraftment and multilineage hematopoietic differentiation that included robust CD4+ T-cell development. Splenocytes isolated from the treatment group were resistant to both R5- and X4-tropic HIV-1 during ex vivo challenge experiments. Treatment group animals challenged with R5-tropic HIV-1 displayed significant protection of CD4+ T-cells and reduced viral load within peripheral blood and lymphoid tissues up to 14 weeks postinfection. Gene-marking and transgene expression were confirmed stable at 26 weeks post-transplantation. These data strongly support the use of LVsh5/C46 lentiviral vector in gene and cell therapeutic applications for inhibition of HIV-1 infection.
RESUMO
We previously showed that a 48-h intravenous lipid infusion in rats induces pancreatic beta-cell hypersensitivity to catecholamines. Our aim was to study the lipid-related changes that may account for such hypersensitivity in pancreatic islets. We show here that a 48-h increase in plasma FFA alters the binding characteristics of beta-cell alpha2 adrenoceptors in rats. Lipid infusion decreases pancreatic norepinephrine (NE) turnover rate by 28%, reflecting a reduction of pancreatic NE stores. Following lipid infusion, the density of alpha2 adrenoceptor binding sites is significantly lower and receptor affinity higher, both in islet homogenates (by three- and fivefold, respectively) and isolated whole beta-cells (by two- and sixfold, respectively). These changes correlate with the elevated insulin response to glucose found in lipid-infused rats. We also found a modification of islet phospholipid content, particularly in phosphoethanolamine species containing infused FA such as palmitate, oleate, stearate, and linoleate. This may account for the modifications in receptor affinity. These results suggest that hyperlipidemia-associated pathologies such as diabetes and obesity not only may result from alterations of metabolic pathways but also may be a consequence of early modifications in nervous firing rates and signal transduction pathways.
Assuntos
Hiperlipidemias/metabolismo , Ilhotas Pancreáticas/metabolismo , Fosfolipídeos/metabolismo , Receptores Adrenérgicos alfa 2/metabolismo , Animais , Catecolaminas/sangue , Ácidos Graxos não Esterificados/sangue , Glicerol/sangue , Hiperlipidemias/sangue , Hiperlipidemias/complicações , Insulina/sangue , Masculino , Norepinefrina/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Receptores Adrenérgicos alfa 2/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Espectrometria de Massas por Ionização por Electrospray , Triglicerídeos/sangueRESUMO
In vivo and in vitro exposure to stimulants has been associated with increased levels of HIV infection in PBMCs. Among these lymphocyte subsets, quiescent CD4(+) T cells make up the majority of circulating T cells in the blood. Others and we have demonstrated that HIV infects this population of cells inefficiently. However, minor changes in their cell state can render them permissive to infection, significantly impacting the viral reservoir. We have hypothesized that stimulants, such as cocaine, may perturb the activation state of quiescent cells enhancing permissiveness to infection. Quiescent T cells isolated from healthy human donors were exposed to cocaine and infected with HIV. Samples were harvested at different time-points to assess the impact of cocaine on their susceptibility to infection at various stages of the HIV life cycle. Our data show that a 3-day exposure to cocaine enhanced infection of quiescent cells, an effect that appears to be mediated by σ1R and D4R. Overall, our results indicate that cocaine-mediated effects on quiescent T cells may increase the pool of infection-susceptible T cells. The latter underscores the impact that stimulants have on HIV-seropositive individuals and the challenges posed for treatment.
Assuntos
Cocaína/farmacologia , Infecções por HIV/patologia , HIV/fisiologia , Linfócitos T/virologia , Internalização do Vírus/efeitos dos fármacos , HIV/efeitos dos fármacos , Humanos , Cinética , Fenótipo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Dopamina D4/metabolismo , Receptores sigma/metabolismo , Transcrição Reversa/efeitos dos fármacos , Linfócitos T/efeitos dos fármacos , Proteínas Virais/genética , Proteínas Virais/metabolismo , Receptor Sigma-1RESUMO
Small animal models such as mice have been extensively used to study human disease and to develop new therapeutic interventions. Despite the wealth of information gained from these studies, the unique characteristics of mouse immunity as well as the species specificity of viral diseases such as human immunodeficiency virus (HIV) infection led to the development of humanized mouse models. The earlier models involved the use of C. B 17 scid/scid mice and the transplantation of human fetal thymus and fetal liver termed thy/liv (SCID-hu) (1, 2) or the adoptive transfer of human peripheral blood leukocytes (SCID-huPBL) (3). Both models were mainly utilized for the study of HIV infection. One of the main limitations of both of these models was the lack of stable reconstitution of human immune cells in the periphery to make them a more physiologically relevant model to study HIV disease. To this end, the BLT humanized mouse model was developed. BLT stands for bone marrow/liver/thymus. In this model, 6 to 8 week old NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) immunocompromised mice receive the thy/liv implant as in the SCID-hu mouse model only to be followed by a second human hematopoietic stem cell transplant (4). The advantage of this system is the full reconstitution of the human immune system in the periphery. This model has been used to study HIV infection and latency (5-8). We have generated a modified version of this model in which we use genetically modified human hematopoietic stem cells (hHSC) to construct the thy/liv implant followed by injection of transduced autologous hHSC (7, 9). This approach results in the generation of genetically modified lineages. More importantly, we adapted this system to examine the potential of generating functional cytotoxic T cells (CTL) expressing a melanoma specific T cell receptor. Using this model we were able to assess the functionality of our transgenic CTL utilizing live positron emission tomography (PET) imaging to determine tumor regression (9). The goal of this protocol is to describe the process of generating these transgenic mice and assessing in vivo efficacy using live PET imaging. As a note, since we use human tissues and lentiviral vectors, our facilities conform to CDC NIH guidelines for Biosafety Level 2 (BSL2) with special precautions (BSL2+). In addition, the NSG mice are severely immunocompromised thus, their housing and maintenance must conform to the highest health standards (http://jaxmice.jax.org/research/immunology/005557-housing.html).