Comprehensive Analysis of Human Cytomegalovirus MicroRNA Expression during Lytic and Quiescent Infection

Background Human cytomegalovirus (HCMV) encodes microRNAs (miRNAs) that function as post-transcriptional regulators of gene expression during lytic infection in permissive cells. Some miRNAs have been shown to suppress virus replication, which could help HCMV to establish or maintain latent infection. However, HCMV miRNA expression has not been comprehensively examined and compared using cell culture systems representing permissive (lytic) and semi-permissive vs. non-permissive (latent-like) infection. Methods Viral miRNAs levels and expression kinetics during HCMV infection were determined by miRNA-specific stem-loop RT-PCR. HCMV infected THP-1 (non-permissive), differentiated THP-1 (d-THP-1, semi-permissive) and human embryo lung fibroblasts (HELs, fully-permissive) were examined. The impact of selected miRNAs on HCMV infection (gene expression, genome replication and virus release) was determined by Western blotting, RT-PCR, qPCR, and plaque assay. Results Abundant expression of 15 HCMV miRNAs was observed during lytic infection in HELs; highest peak inductions (11- to 1502-fold) occurred at 48 hpi. In d-THP-1s, fourteen mRNAs were detected with moderate induction (3- to 288-fold), but kinetics of expression was generally delayed for 24 h relative to HELs. In contrast, only three miRNAs were induced to low levels (3- to 4-fold) during quiescent infection in THP-1s. Interestingly, miR-UL70-3p was poorly induced in HEL (1.5-fold), moderately in THP-1s (4-fold), and strongly (58-fold) in d-THP-1s, suggesting a potentially specific role for miR-UL70-3p in THP-1s and d-THP-1s. MiR-US33, -UL22A and -UL70 were further evaluated for their impact on HCMV replication in HELs. Ectopic expression of miR-UL22A and miR-UL70 did not affect HCMV replication in HELs, whereas miR-US33 inhibited HCMV replication and reduced levels of HCMV US29 mRNA, confirming that US29 is a target of miR-US33. Conclusions Viral miRNA expression kinetics differs between permissive, semi-permissive and quiescent infections, and miR-US33 down-regulates HCMV replication. These results suggest that miR-US33 may function to impair entry into lytic replication and hence promote establishment of latency

La Cross-présentation dans la réponse T CD8+ contre le Cytomégalovirus humain

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Sensibilisation par P73 à l'apoptose induite par les ligands de mort de la famille du TNF et effets subversifs du cytomégalovirus humain

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Sida et femme enceinte (épidemiologie, traitement)

Le nombre de femmes séropositives débutant une grossesse ou désirant la débuter, sous multithérapie ne cesse de croître. Les femmes représentent près de 50% des personnes infectées par le VIH dans le monde, et 57% en Afrique subsaharienne. Après un bref rappel sur le virus de l'immunodéficience humaine, ce travail décrit l'épidémiologie de l'infection par le VIH chez la femme, ainsi que les mécanismes et facteurs de risque de la Transmission Mère-Enfant (TME).L'objectif de ce travail est de rappeler l'historique des différentes stratégies thérapeutiques de prise en charge de la femme enceinte séropositive ainsi que les recommandations actuelles en France. Les données actuellement disponibles sur la toxicité des traitements antirétroviraux chez la mère et l'enfant sont également présentées.Ce travail est illustré par le cas d'une patiente infectée par le VIH-1, originaire du Congo, qui a mis au monde deux enfants séronégatifs.CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF

Le cytomégalovirus humain au sein du système nerveux (interférences avec la réponse lymphocytaire T CD8+ anti-virale et l'apoptose dépendante de p53 et p73)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Comparaison des souches de virus d'Epstein-Barr présentés en différents sites de patients atteints de carcinome indifférencié du nasopharynx

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Interaction de l'entérotoxine B de Staphylococcus aureus avec le TLR2 et le TLR4 dans la physiopathologie

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Bcl-3-regulated transcription from major immediate-early promoter of human cytomegalovirus in monocyte-derived macrophages.

International audienceMonocytes/macrophages are key cells in the pathogenesis of human CMV (HCMV) infection, but the in vitro rate of viral production in primary human monocyte-derived macrophages (MDM) is considerably lower than in fibroblasts. Considering that the NF-kappaB signaling pathway is potentially involved in the replication strategy of HCMV through efficient transactivation of the major immediate-early promoter (MIEP), efficient viral replication, and late gene expression, we investigated the composition of the NF-kappaB complex in HCMV-infected MDMs and fibroblasts. Preliminary studies showed that HCMV could grow in primary MDM culture but that the viral titer in culture supernatants was lower than that observed in the supernatants of more permissive MRC5 fibroblasts. EMSA and microwell colorimetric NF-kappaB assay demonstrated that HCMV infection of MDMs increased p52 binding activity without activating the canonical p50/p65 complex. Moreover, Bcl-3 was up-regulated and was demonstrated to associate with p52, indicating p52/Bcl-3 complexes as the major component of the NF-kappaB complex in MDMs. Luciferase assays in promonocytic U937 cells transfected with an MIEP-luciferase reporter construct demonstrated MIEP activation in response to p52 and Bcl-3 overexpression. Chromatin immunoprecipitation assay demonstrated that p52 and Bcl-3 bind the MIEP in acutely HCMV-infected MDMs. In contrast, HCMV infection of MRC5 fibroblasts resulted in activation of p50/p65 heterodimers. Thus, activation of p52/Bcl-3 complexes in MDMs and p50/p65 heterodimers in fibroblasts in response to HCMV infection might explain the low-level growth of the virus in MDMs vs efficient growth in fibroblasts