Development of New Therapeutics Targeting Biofilm Formation by the Opportunistic Pulmonary Pathogens Pseudomonas aeruginosa and Aspergillus fumigatus
Abstract
Major accomplishments this period: 1. Pharmacokinetic studies of the GH enzymes were completed (Major Task 3). GH variants (Major Task 4) were developed for Sph3, Ega3 and PelA, to address their short half-life in vivo (PelA, Sph3). A test for GH resistance to neutrophil lysate and to the commercial protease elastase was developed. , Native and variant GHs show sensitivity to neutrophil lysate and elastase. PEGylation protects the proteins from elastase. The PelA orthologue showed identical activity and increased resistance to elastase and improved pharmacokinetics. The Sph3 orthologue showed no improvement.2.Survival of immunosuppressed mice challenged with A. fumigatus was not observed in a chronic model of aspergillosis (Major Task 6) suggesting that GHs are inefficient against an established fungal infection. Conversely, intra-tracheal injection of any of the GHs was protective in an acute model of aspergillosis (Major Task 5). But combination of GHs (Sph3 and PelA) with parconazole failed to improve the outcome of acute disease further than the effect of the antifungal or of the GH alone (Major Task 7). Study with caspofungin is upcoming.3.Conversely to Aspergillus infection, GH alone failed to improve the outcome in mice challenged with P.aeruginosa in an acute model (Major Task 5); au contraire, the results of these studies indicate that GH therapy alone may increase bacterial dissemination, in particular towards blood, thus worsening the infection. The addition of PslG, PelA, Ega3 or PslG/Ega3 to ciprofloxacin failed to potentiate the antibiotic activity, although these combination of GH/antibiotic protected against bacterial dissemination. One exception is the addition of PslG/PelA combination to ciprofloxacin: it potentiated the decrease of bacterial burden by ciprofloxacin (Major Task 7); this suggests the need of a GH against Pel plus one GH against Psl. Data from the chronic model are being produced (Major Task 6).
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2019
- Accession Number
- AD1086164
Entities
People
- Donald C Sheppard
Organizations
- McGill University Health Centre