RESUMO
Mammals have evolved many antiviral factors impacting different steps of the viral life cycle. Associated with chromatin-modifying enzymes, the cellular cofactor CTIP2 contributes to HIV-1 gene silencing in latently infected reservoirs that constitute the major block toward an HIV cure. We report, for the first time, that the virus has developed a strategy to overcome this major transcriptional block. Productive HIV-1 infection results in a Vpr-mediated depletion of CTIP2 in microglial cells and CD4+ T cells, two of the major viral reservoirs. Associated to the Cul4A-DDB1-DCAF1 ubiquitin ligase complex, Vpr promotes CTIP2 degradation via the proteasome pathway in the nuclei of target cells and notably at the latent HIV-1 promoter. Importantly, Vpr targets CTIP2 associated with heterochromatin-promoting enzymes dedicated to HIV-1 gene silencing. Thereby, Vpr reactivates HIV-1 expression in a microglial model of HIV-1 latency. Altogether our results suggest that HIV-1 Vpr mediates the depletion of the cellular repressor CTIP2 to counteract viral gene silencing.
Assuntos
Inativação Gênica , HIV-1/genética , Proteínas Repressoras/genética , Proteínas Supressoras de Tumor/genética , Produtos do Gene vpr do Vírus da Imunodeficiência Humana/genética , Linhagem Celular , Células Cultivadas , Regulação Viral da Expressão Gênica , Células HEK293 , Infecções por HIV/virologia , HIV-1/metabolismo , HIV-1/fisiologia , Interações Hospedeiro-Patógeno/genética , Humanos , Células Jurkat , Complexo de Endopeptidases do Proteassoma/metabolismo , Ligação Proteica , Proteólise , Proteínas Repressoras/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Latência Viral/genética , Replicação Viral/genética , Produtos do Gene vpr do Vírus da Imunodeficiência Humana/metabolismoRESUMO
BACKGROUND: Neuropathic pain triggered by peripheral nerve lesion is extremely difficult to manage with current approaches, hence the importance of exploring therapeutic alternatives. METHODS: We have analysed adipose-derived mesenchymal stem cells (AD-MSCs) and fibroblast growth factor 1 gene-transfected adipose-derived mesenchymal stem cells (AD-MSCs FGF1 ) on chronic constriction injury (CCI). The mechanical and thermal hypersensitivity were assessed using the von Frey filament, radiant heat and acetone drop tests. Histopathological and apoptotic changes and the level of FGF1, GFAP and TNFα proteins were assessed in the lumbar portion (L4-L6). Moreover, AD-MSCs FGF1 were labelled with 99m Tc -HMPAO and isolated organ counting were performed upon AD-MSCs FGF1 administration. RESULTS: Administration of AD-MSCs FGF1 attenuated the CCI-induced mechanical and thermal hypersensitivity. Spinal structural alterations and apoptosis were decreased in the AD-MSCs FGF1 group. The injection of either phosphate-buffered saline or normal NIH3T3 fibroblasts could not attenuate the behavioural symptoms of neuropathic pain. Increased genetically engineered cells were counted in the injured sciatic nerve and the elevated levels of FGF1 were detected in the spinal tissue. Stem cell therapy lead to decrement the level of the CCI-induced TNF-α and GFAP expression. CONCLUSION: The intravenous administration of AD-MSCs FGF1 could be considered as a potential remedy for the management of neuropathic pain. SIGNIFICANCE: AD-MSCs FGF1 attenuated the CCI-induced mechanical and thermal hypersensitivity. Spinal structural alterations and apoptosis were significantly decreased in the AD-MSCs FGF1 group. Elevated levels of FGF1 were detected in the spinal tissue.
Assuntos
Fator 1 de Crescimento de Fibroblastos/genética , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/metabolismo , Neuralgia/terapia , Animais , Fator 1 de Crescimento de Fibroblastos/metabolismo , Masculino , Camundongos , Células NIH 3T3 , Neuralgia/genética , Neuralgia/metabolismo , Ratos Sprague-Dawley , Nervo Isquiático/lesõesRESUMO
OBJECTIVES: Fungi belonging to the Metarhizium anisopliae complex comprise ubiquitous arthropod pathogenic moulds used as mycopesticides. Rare cases of human infections due to M. anisopliae have been reported. We hypothesize misidentifications of fungal strains implicated in these cases or used in mycopesticides. METHODS: A review of the literature was conducted to identify previously published cases. We collected some of these previous described strains and reported new cases, and a French mycopesticide containing M. anisopliae. All identifications were performed based on elongation factor-1α gene sequencing. RESULTS: We report eight new cases of Metarhizium infection in humans (three from France and five from Australia). The strains isolated from these cases, and three others from already published cases and reported as M. anisopliae, were molecularly identified based on elongation factor-1α (Ef1-α) gene sequencing as follows: Metarhizium robertsii (six), Metarhizium guizhouense (three), Metarhizium brunneum (one) and Metarhizium pingshaense (one). CONCLUSIONS: In this study, we report new human cases of Metarhizium infections, and, based on Ef-1α gene sequencing, we demonstrate the misidentification of species in case reports. We also correct the species identification of a strain reported as M. anisopliae used in a commercially available mycopesticide. According to our results, none of the strains from the human infection reports reviewed belongs to the species M. anisopliae.
