PROJECT SUMMARY
Infection with a pathogen can have a significant impact on drug metabolism and disposition in the host
and can even determine treatment outcomes. This “pathobiome”, meaning the total amount of pathogenic
microbe present during an infection, may have a profound impact on drug metabolism in the disease state
when individuals are much more likely to receive drugs, particularly antibiotics. Despite the mounting evidence,
we still understand little regarding the capacity of pathogens to contribute to drug metabolism in the host.
Understanding the role of pathogens in drug metabolism will fill a gap in our current knowledge and it also has
the potential to lead to the identification of novel antimicrobial drug targets. Our preliminary data demonstrates
that CYPs from Pseudomonas aeruginosa (PA), an important opportunistic pathogen in the lung of cystic
fibrosis (CF) patients, are highly promiscuous and capable of metabolizing drugs - including the antibiotic
ciprofloxacin used to treat PA infections. Furthermore, we have also demonstrated that secondary metabolites
produced by PA can induce expression of human CYP1A2, potentially leading to increased clearance of
ciprofloxacin in the host. This specific application focuses on characterizing the role of CYP enzymes and
secondary metabolites from PA. Our central hypothesis is that P. aeruginosa can modulate drug metabolism
in the local environment of the lung in order to reduce the effectiveness of drug therapy. In order to test our
hypothesis, we propose the following specific aims: 1. Characterize the metabolic capability of P. aeruginosa
CYPs to metabolize drugs relevant to the patient CF host; 2. Determine the potency and specificity of P.
aeruginosa secondary metabolites to induce expression of host CYP drug metabolizing enzymes in human
lung cells, and 3. Identify the structural contributions to substrate and inhibitor specificity for P. aeruginosa
CYPs using 19F biomolecular NMR. Characterizing the ability of PA to metabolize drugs in the host will allow us
to quantitatively determine the contribution of PA to host drug metabolism at the site of infection and develop
inhibitors that may limit PA antibiotic resistance. Understanding the impact of the P. aeruginosa pathobiome
contribution to drug metabolism and antibiotic resistance in the host is paradigm shifting in that it will expand
our idea of pathogen regulation of host processes and provide new opportunities for potential adjuvant drug
targeting in the pathogen to increase the sensitivity to otherwise effective antibiotics.
