The Adherent/Invasive Escherichia coli Strain LF82 Invades and Persists in Human Prostate Cell Line RWPE-1, Activating a Strong Inflammatory Response.

Maria P Conte,Antonietta L Conte,Anna T Palamara,Marta Aleandri,Paola De Cesaris,Cecilia Ambrosi,Massimiliano Marazzato,Anna Riccioli,Carlo Zagaglia,Guido Gambara,Mauro Nicoletti,Catia Longhi,Elio Ziparo,Fioretta Palombi,S M Payne

doi:10.1128/iai.00438-16

Abstract

Adherent/invasive Escherichia coli (AIEC) strains have recently been receiving increased attention because they are more prevalent and persistent in the intestine of Crohn's disease (CD) patients than in healthy subjects. Since AIEC strains show a high percentage of similarity to extraintestinal pathogenic E. coli (ExPEC), neonatal meningitis-associated E. coli (NMEC), and uropathogenic E. coli (UPEC) strains, here we compared AIEC strain LF82 with a UPEC isolate (strain EC73) to assess whether LF82 would be able to infect prostate cells as an extraintestinal target. The virulence phenotypes of both strains were determined by using the RWPE-1 prostate cell line. The results obtained indicated that LF82 and EC73 are able to adhere to, invade, and survive within prostate epithelial cells. Invasion was confirmed by immunofluorescence and electron microscopy. Moreover, cytochalasin D and colchicine strongly inhibited bacterial uptake of both strains, indicating the involvement of actin microfilaments and microtubules in host cell invasion. Moreover, both strains belong to phylogenetic group B2 and are strong biofilm producers. In silico analysis reveals that LF82 shares with UPEC strains several virulence factors: namely, type 1 pili, the group II capsule, the vacuolating autotransporter toxin, four iron uptake systems, and the pathogenic island (PAI). Furthermore, compared to EC73, LF82 induces in RWPE-1 cells a marked increase of phosphorylation of mitogen-activated protein kinases (MAPKs) and of NF-κB already by 5 min postinfection, thus inducing a strong inflammatory response. Our in vitro data support the hypothesis that AIEC strains might play a role in prostatitis, and, by exploiting host-cell signaling pathways controlling the innate immune response, likely facilitate bacterial multiplication and dissemination within the male genitourinary tract.

Highlights

Catia Longhia Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italya; Department of Medical, Oral and Biotechnological Sciences, G
Since Adherent/invasive E. coli (AIEC) strains show a high percentage of similarity to extraintestinal pathogenic E. coli (ExPEC), neonatal meningitis-associated E. coli (NMEC), and uropathogenic E. coli (UPEC) strains, here we compared AIEC strain LF82 with a UPEC isolate to assess whether LF82 would be able to infect prostate cells as an extraintestinal target
ExPEC strains have been classified into three major groups based on disease association, comprising uropathogenic E. coli (UPEC), neonatal meningitis-associated E. coli (NMEC), and sepsis-causing E. coli (SEPEC)

Summary

Introduction

We have recently demonstrated the ability of as many as 58 UPEC strains to adhere to and invade human prostate cells with high efficiency [33] These findings, together with the carriage of some virulence-associated genes characteristic of ExPEC pathovars, led us to hypothesize that AIEC strains may infect body sites other than the intestine. To explore this point, in this article, we compare the behavior of AIEC strain LF82 to that of an E. coli strain (EC73) isolated from a subject with recurrent UTIs. In the present study, the ability of strains LF82 and EC73 to adhere to, invade, survive intracellularly, and induce inflammation was studied by experimentally infecting the human prostate RWPE-1 cell line. Our data led us to suggest that AIEC strains have the potential to invade prostate cells, potentially causing prostatitis

Methods

Results

Conclusion