In Vitro interaction of Pseudomonas aeruginosa with human middle ear epithelial cells

Rahul Mittal, M'Hamed Grati, Robert Gerring, Patricia Blackwelder, Denise Yan, Jian Dong Li, Xue Zhong Liu

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Background: Otitis media (OM) is an inflammation of the middle ear which can be acute or chronic. Acute OM is caused by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis whereas Pseudomonas aeruginosa is a leading cause of chronic suppurative otitis media (CSOM). CSOM is a chronic inflammatory disorder of the middle ear characterized by infection and discharge. The survivors often suffer from hearing loss and neurological sequelae. However, no information is available regarding the interaction of P. aeruginosa with human middle ear epithelial cells (HMEECs). Methodology and Findings: In the present investigation, we demonstrate that P. aeruginosa is able to enter and survive inside HMEECs via an uptake mechanism that is dependent on microtubule and actin microfilaments. The actin microfilament disrupting agent as well as microtubule inhibitors exhibited significant decrease in invasion of HMEECs by P. aeruginosa. Confocal microscopy demonstrated F-actin condensation associated with bacterial entry. This recruitment of F-actin was transient and returned to normal distribution after bacterial internalization. Scanning electron microscopy demonstrated the presence of bacteria on the surface of HMEECs, and transmission electron microscopy confirmed the internalization of P. aeruginosa located in the plasma membrane-bound vacuoles. We observed a significant decrease in cell invasion of OprF mutant compared to the wild-type strain. P. aeruginosa induced cytotoxicity, as demonstrated by the determination of lactate dehydrogenase levels in culture supernatants of infected HMEECs and by a fluorescent dye-based assay. Interestingly, OprF mutant showed little cell damage compared to wild-type P. aeruginosa. Conclusions and Significance: This study deciphered the key events in the interaction of P. aeruginosa with HMEECs in vitro and highlighted the role of bacterial outer membrane protein, OprF, in this process. Understanding the molecular mechanisms in the pathogenesis of CSOM will help in identifying novel targets to design effective therapeutic strategies and to prevent hearing loss.

Original languageEnglish (US)
Article numbere91885
JournalPloS one
Volume9
Issue number3
DOIs
StatePublished - Mar 14 2014

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

Fingerprint Dive into the research topics of 'In Vitro interaction of Pseudomonas aeruginosa with human middle ear epithelial cells'. Together they form a unique fingerprint.

  • Cite this