generation-amplification-titration-recombinant-respiratory-syncytial

Generation, Amplification, and Titration of Recombinant Respiratory Syncytial Viruses

The use of recombinant viruses has become crucial in basic or applied virology. Reverse genetics has been proven to be an extremely powerful technology, ...

Université de Versailles St. Quentin

The airways of patients with cystic fibrosis (CF) exhibit decreased nitric oxide (NO) concentrations, which might affect airway function. The aim of this study was to determine the effects of NO on ion transport in human airway epithelia. Primary cultures of non-CF and CF bronchial and bronchiolar epithelial cells were exposed to the NO donor sodium nitroprusside (SNP), and bioelectric variables were measured in Ussing chambers. Amiloride was added to inhibit the Na(+) channel ENaC, and forskolin and ATP were added successively to stimulate cAMP- and Ca(2+)-dependent Cl(-) secretions, respectively. The involvement of cGMP was assessed by measuring the intracellular cGMP concentration in bronchial cells exposed to SNP and the ion transports in cultures exposed to 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one, an inhibitor of the soluble guanylate cyclase (ODQ), or to 8Z, a cocktail of 8-bromo-cGMP and zaprinast (phosphodiesterase 5 inhibitor). SNP decreased the baseline short-circuit current (I(sc)) and the changes in I(sc) induced by amiloride, forskolin, and ATP in non-CF bronchial and bronchiolar cultures. The mechanism of this inhibition was studied in bronchial cells. SNP increased the intracellular cGMP concentration ([cGMP](i)). The inhibitory effect of SNP was abolished by 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, an NO scavenger (PTIO) and ODQ and was partly mimicked by increasing [cGMP](i). In CF cultures, SNP did not significantly modify ion transport; in CF bronchial cells, 8Z had no effect; however, SNP increased the [cGMP](i). In conclusion, exogenous NO may reduce transepithelial Na(+) absorption and Cl(-) secretion in human non-CF airway epithelia through a cGMP-dependent pathway. In CF airways, the NO/cGMP pathway appears to exert no effect on transepithelial ion transport.

Effect of nitric oxide on epithelial ion transports in noncystic fibrosis and cystic fibrosis human proximal and distal airways.

Infection of cells by respiratory syncytial virus induces the formation of cytoplasmic inclusion bodies (IBs) where all the components of the viral RNA polymerase complex are concentrated. However, the exact organization and function of these IBs remain unclear. In this study, we use conventional and super-resolution imaging to dissect the internal structure of IBs. We observe that newly synthetized viral mRNA and the viral transcription anti-terminator M2-1 concentrate in IB sub-compartments, which we term "IB-associated granules" (IBAGs). In contrast, viral genomic RNA, the nucleoprotein, the L polymerase and its cofactor P are excluded from IBAGs. Live imaging reveals that IBAGs are highly dynamic structures. Our data show that IBs are the main site of viral RNA synthesis. They further suggest that shortly after synthesis in IBs, viral mRNAs and M2-1 transiently concentrate in IBAGs before reaching the cytosol and suggest a novel post-transcriptional function for M2-1.Respiratory syncytial virus (RSV) induces formation of inclusion bodies (IBs) sheltering viral RNA synthesis. Here, Rincheval et al. identify highly dynamic IB-associated granules (IBAGs) that accumulate newly synthetized viral mRNA and the viral M2-1 protein but exclude viral genomic RNA and RNA polymerase complexes.

Sabine Blouquit-Laye

UMR 1173 Institut national de la santé et de la recherche médicale (INSERM)

Université de Versailles St. Quentin

Generation, Amplification, and Titration of Recombinant Respiratory Syncytial Viruses

Sabine Blouquit-Laye

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Université de Versailles St. Quentin

Generation, Amplification, and Titration of Recombinant Respiratory Syncytial Viruses

UMR 1173 Institut national de la santé et de la recherche médicale (INSERM)