Pseudomonas aeruginosa virulence proteins pseudolysin and protease IV impede cutaneous wound healing

Abstract

The intricate biological process of cutaneous wound healing is achieved through precise and highly programmed events. Dermal fibroblasts and keratinocytes play a significant role in the process of reepithelialization during wound healing. Pathogenic bacteria such as Pseudomonas aeruginosa (P. aeruginosa) may delay the proliferative phase of wound repair by secreting their proteins leading to delayed or impaired wound healing. We have analyzed three virulent strains of P. aeruginosa isolated from the wound environment which also differed in their ability to produce biofilms. Mass spectrometric analysis of differentially expressed secreted proteins by three virulent strains of P. aeruginosa revealed peptides from pseudolysin and protease IV expressed from lasB and prpL genes. Pseudolysin and protease IV recombinant proteins were tested for their ability to modulate wound healing in several cell types of wound microenvironment in in vitro and in vivo models. Both pseudolysin and protease IV inhibited migration and survival of fibroblasts, keratinocytes, and endothelial cells. In three dimensional spheroid endothelial models and matrigel assays these proteins impeded sprouting and tube formation. In a mouse model of excision wound, pseudolysin and protease IV treatment showed reduced collagen content, inhibited neovascularization and epithelialization, and delayed wound contraction. Furthermore, pseudolysin and protease IV treatment resulted in a significant increase in plasma IL-6 levels when compared to vehicle control and control, suggesting the induction of a state of prolonged inflammation. Taken together, our data indicate pseudolysin and protease IV secreted from biofilm producing and antibiotic resistant P. aeruginosa in wound microenvironment produce both local and systemic effects that is detrimental to the maintenance of tissue homeostasis. Hence, these proteins may serve as potential therapeutic targets toward better clinical management of wounds.

An Organ System-Based Synopsis ofPseudomonas aeruginosaVirulence

“…Infecting a biopsy-punch wound of diabetic mice with biofilm-grown P. aeruginosa delayed wound healing from 4 weeks to 6–8 weeks compared to uninfected wounds [ 447 ]. Both LasB elastase and protease IV reduced wound repair through the inhibition of cell migration and angiogenesis [ 448 ]. Both proteases were better produced by high biofilm-forming strains isolated from diabetic foot ulcers compared to moderate or low biofilm-forming isolates from the same infection site.…”

“…Both proteases were better produced by high biofilm-forming strains isolated from diabetic foot ulcers compared to moderate or low biofilm-forming isolates from the same infection site. This impact on wound healing was demonstrated by treating mouse wounds with each purified proteases [ 448 ]. Jacobsen et al .…”

Negative pressure wound therapy with intermittent irrigation for treatment of post-traumatic giant abscess: A case report

“…Wounds infected with biofilm-forming bacteria have posed additional difficulties in wound healing for decades. Free leakage of bile into the peritoneum perpetuates the growth of opportunistic biofilm-forming Pseudomonas aeruginosa , allowing the secretion of its virulence factors, pseudolysin and protease IV, which affects the survival rate of fibroblast, impede cell migration, and inhibit angiogenesis [9] . NPWT is an effective strategy for managing contaminated wounds by reducing virulence factors and bacteria proliferation [10] .…”

Untitled

“…[62] P. aeruginosa also secretes a plethora of proteases resulting in collagen, fi brinogen and elastin degradation, inhibition of PMNs and complement systems, and basement membrane degradation. [261,262] Similarly, proteases secreted by S. aureus also degrade collagen and elastin. The ability to degrade surfaceassociated adhesins enables bacterial phenotype transition from adhesive to invasive.…”