Nucleotide-mediated inhibition of alveolar fluid clearance in BALB/c mice after respiratory syncytial virus infection

Abstract

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract disease in infants and children worldwide. Intranasal infection of BALB/c mice with RSV strain A2, but not ultraviolet-inactivated RSV, for 2 or 4 days reduced basal alveolar fluid clearance (AFC), a seminal function of bronchoalveolar epithelium, and caused loss of AFC sensitivity to amiloride inhibition. Reduced AFC was temporally associated with increased lung water content but was not a consequence of increased epithelial permeability or cell death. Reduced AFC was also not due to decreased transcription of epithelial Na+ channel subunit genes in lung tissue. RSV-mediated inhibition of AFC 2 days after infection was rapidly prevented by addition to the instillate of P2Y receptor antagonists (suramin and XAMR-0721) or enzymes that degrade UTP, but not those that degrade ATP. After UTP degradation, AFC returned to control levels but was no longer sensitive to amiloride. UTP at nanomolar concentrations recapitulated the AFC inhibitory effect of RSV in normal mice and mice infected with RSV for 6 days, indicating that normalization of AFC at this time point is a consequence of cessation of UTP release, rather than P2Y receptor desensitization. We conclude that RSV infection of the bronchoalveolar epithelium results in reduced AFC as a consequence of autocrine feedback inhibition mediated by UTP. These studies are the first to demonstrate AFC inhibition by an important pulmonary viral pathogen. Reduced AFC may result in formation of an increased volume of fluid mucus, airway congestion, and rhinorrhea, all features of severe RSV disease.

Protective T cell immunity against respiratory syncytial virus is efficiently induced by recombinant BCG

“…2A, significant weight loss was observed for unimmunized animals or mice immunized either with UV-RSV or WT-BCG, as well as BCG-OVA (data not shown). These data are consistent with previous studies indicating that naive mice challenged with RSV can show significant weight loss as early as 24 h after infection (35)(36)(37). In sharp contrast, mice immunized with either BCG-N or BCG-M2 showed no significant weight loss after RSV challenge, similarly to uninfected mice (Fig.…”

Identification of broad-spectrum antiviral compounds and assessment of the druggability of their target for efficacy against respiratory syncytial virus (RSV)

“…It seemed that the MoA of the de novo pyrimidine as a drug target would suit more for a rapidly replicating RNA virus. Indeed, for RSV there were two reports that used the mouse model of RSV and showed that the active metabolite of leflunomide did not have an antiviral effect but did block the immuno-and lung pathology associated with the disease (50,51). However, none of these animal experiments addressed the pharmacokinetics of the drug and, most importantly, the possible toxicity associated with on-target effects.…”

Pulmonary surfactant phosphatidylglycerol inhibits respiratory syncytial virus–induced inflammation and infection

“…RSV and POPG mixtures were prepared in PBS and inoculated intranasally into mice. Aliquots of RSV stocks were inactivated by exposure to 1,800 mJ of UV radiation in a Stratalinker UV cross-linker (UVP), for the purpose of eliminating viral infectivity without significantly altering the conformation of viral proteins, or inactivating endogenous mediators, as previously described (37). UV inactivation reduced RSV infectivity by 8 log units.…”