Distinctive Lacritin Cleavage-Potentiated Bactericidal Alteration of the P. aeruginosa Transcriptome.

Lacritin is a tear, saliva, plasma and cerebrospinal fluid glycoprotein with broad polypharmacology. Its protease generated N-104 proteoform endogenous in tears (and likely elsewhere) is bactericidal and synergizes with the tear thrombin peptide GKY20. In the pathogenic and multidrug resistant PA14 strain of P. aeruginosa, we recently discovered that N-104 at subinhibitory and inhibitory concentrations binds to the outer-membrane lipoprotein YaiW to gain access to the periplasm where it targets and inhibits the inner-membrane ferrous iron transporter FeoB (of FeoABC) as well as PotH, a subunit of the polyamine transporter PotFGHI. Further, PA14 gene expression shifts toward anaerobic respiratory pathways. Here we report N-104-associated transcriptional changes pointing to a reduction in: (i) virulence, (ii) fitness, (iii) metabolism, (iv) stress response, (v) proteostasis, (vii) quorum sensing, and (viii) survival under anaerobic conditions. Upregulated genes are directed towards enhancing PA14: (i) multidrug and (ii) tellurite efflux, coupled with a seemingly PA14 survival attempt at (iii) anaerobic respiration, (iv) translational fidelity and (v) metabolism. The overlap with aminoglycosides (4.3%), β-lactams (0%), cyclic peptides (2.5%), fluoroquinilones (0%) and macrolide (1.9%) classes of antibiotics in P. aeruginosa was minimal. Thus, N-104 appears to widely perturb PA14 fundamental processes in a distinctive manner.