Adherent/invasive Escherichia coli (AIEC) strains are recently receiving increased attention because they are more prevalent and persistent in the intestine of Crohn (CD) patients than in healthy subjects. Since AIEC strains show a high percentage of similarity with ExPEC NMEC and UPEC, here we compared AIEC strain LF82 with a UPEC isolate (strain EC73) to assess whether LF82 could be able to infect prostate cells, as an extra-intestinal 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, 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 of virulence factors reveals that LF82 shares with UPECs 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 MAPKs and of NF-κB already 5 min post-infection, 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 facilitating bacterial multiplication and dissemination within the male genitourinary tract.
Infection and immunity. 2016 Sep 06 [Epub ahead of print]
Maria P Conte, Marta Aleandri, Massimiliano Marazzato, Antonietta L Conte, Cecilia Ambrosi, Mauro Nicoletti, Carlo Zagaglia, Guido Gambara, Fioretta Palombi, Paola De Cesaris, Elio Ziparo, Anna T Palamara, Anna Riccioli, Catia Longhi
Department of Public Health and Infectious Diseases, "Sapienza" University, Rome, Italy ., Department of Public Health and Infectious Diseases, "Sapienza" University, Rome, Italy., Department of Medical, Oral and Biotechnological Sciences "G. D'Annunzio" University, Chieti, Italy., Center of Space Medicine Berlin, Neuromuscular System, Institute of Anatomy, CharitéUniversitätsmedizin Berlin, Germany Department of Anatomy, Histology, Forensic Medicine & Orthopedics, Unit of Histology and Medical Embryology, "Sapienza" University, Rome, Italy., Department of Anatomy, Histology, Forensic Medicine & Orthopedics, Unit of Histology and Medical Embryology, "Sapienza" University, Rome, Italy., Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy., Department of Public Health and Infectious Diseases, Pasteur Institute Cenci Bolognetti Foundation, "Sapienza" University, Rome, Italy IRCCS, San Raffaele Pisana, Rome, Italy.