RNA-Seq Transcriptomic Responses of Full-Thickness Dermal Excision Wounds to Pseudomonas aeruginosa Acute and Biofilm Infection

PLoS One. 2016 Oct 28;11(10):e0165312. doi: 10.1371/journal.pone.0165312. eCollection 2016.

Abstract

Pseudomonas aeruginosa infections of wounds in clinical settings are major complications whose outcomes are influenced by host responses that are not completely understood. Herein we evaluated transcriptomic changes of wounds as they counter P. aeruginosa infection-first active infection, and then chronic biofilm infection. We used the dermal full-thickness, rabbit ear excisional wound model. We studied the wound response: towards acute infection at 2, 6, and 24 hrs after inoculating 106 bacteria into day-3 wounds; and, towards more chronic biofilm infection of wounds similarly infected for 24 hrs but then treated with topical antibiotic to coerce biofilm growth and evaluated at day 5 and 9 post-infection. The wounds were analyzed for bacterial counts, expression of P. aeruginosa virulence and biofilm-synthesis genes, biofilm morphology, infiltrating immune cells, re-epithelialization, and genome-wide gene expression (RNA-Seq transcriptome). This analysis revealed that 2 hrs after bacterial inoculation into day-3 wounds, the down-regulated genes (infected vs. non-infected) of the wound edge were nearly all non-coding RNAs (ncRNAs), comprised of snoRNA, miRNA, and RNU6 pseudogenes, and their down-regulation preceded a general down-regulation of skin-enriched coding gene expression. As the active infection intensified, ncRNAs remained overrepresented among down-regulated genes; however, at 6 and 24 hrs they changed to a different set, which overlapped between these times, and excluded RNU6 pseudogenes but included snRNA components of the major and minor spliceosomes. Additionally, the raw counts of multiple types of differentially-expressed ncRNAs increased on post-wounding day 3 in control wounds, but infection suppressed this increase. After 5 and 9 days, these ncRNA counts in control wounds decreased, whereas they increased in the infected, healing-impaired wounds. These data suggest a sequential and coordinated change in the levels of transcripts of multiple major classes of ncRNAs in wound cells transitioning from inflammation to the proliferation phase of healing.

MeSH terms

  • Animals
  • Biofilms*
  • Female
  • Gene Expression Regulation / physiology
  • Pseudomonas Infections / physiopathology*
  • Pseudomonas aeruginosa*
  • RNA / genetics
  • RNA / physiology
  • Rabbits
  • Skin Diseases, Bacterial / microbiology
  • Skin Diseases, Bacterial / physiopathology*
  • Transcriptome / physiology*
  • Wounds and Injuries / microbiology*
  • Wounds and Injuries / physiopathology

Substances

  • RNA

Grants and funding

This work was supported in part by the US Army Medical Research and Materiel Command, Combat Casualty Care Research Directorate and the Naval Medical Research Center's Advanced Medical Development program (MIPR N3239815MHX040) (KPL)and the Research Associateship Program from the National Research Council (SLRK). P. D’Arpa is supported by the U. S. Army Research Laboratory and the U.S. Army Research Office under contract/grant number W911NF1310376 to The Geneva Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.