Mohamed Mohamed Elashiry1,2, Fucong Tian3, Mahmoud Elashiry2, Rana Zeitoun4,5, Ranya Elsayed2, Matthew L Andrews3, Brian E Bergeon3, Christopher Cutler2, Franklin Tay3. 1. Department of Endodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt. 2. Department of Periodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA. 3. Department of Endodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA. 4. Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt. 5. Department of Oral Biology and Diagnostic Science, The Dental College of Georgia, Augusta University, Augusta, GA, USA.
Abstract
Background: The macrophage is an innate immune defense cell involved in pathogen recognition and clearance. Aim: In view of the diversity of the macrophage phenotype and function, the present study investigated how Enterococcus faecalis infection affects the differentiation, phenotype and cytokine profile of macrophages. Methods: Murine bone marrow-derived stem cells were co-cultured with E. faecalis before and after differentiation. Macrophage M0 polarization towards M1 or M2 was initiated at day 6 by addition of LPS and INF-γ, or IL-4 and IL-13, respectively. Results: E. faecalis did not inhibit macrophage differentiation and were identified within macrophages. Viability of the macrophages infected with E. faecalis prior to differentiation was enhanced, evidenced by apoptosis inhibition, as was expression of CD38 and IRF5 proteins, indicators of M1-like polarization. These M1-like macrophages expressed an aberrant cytokine mRNA profile, with reduction in inflammatory cytokines IL-1β and IL-12 and increase in regulatory cytokine IL-10. No changes in TNF-α or TGF-β1 were detected, compared with the control groups. This atypical M1-like phenotype was retained even upon stimulation with growth factors that normally trigger their development into M2 macrophages. Conclusions: These findings suggested that E. faecalis infection of bone marrow-derived stem cells during differentiation into macrophages induces an atypical M1-like phenotype associated with intracellular bacterial survival.
Background: The macrophage is an innate immune defense cell involved in pathogen recognition and clearance. Aim: In view of the diversity of the macrophage phenotype and function, the present study investigated how Enterococcus faecalis infection affects the differentiation, phenotype and cytokine profile of macrophages. Methods: Murine bone marrow-derived stem cells were co-cultured with E. faecalis before and after differentiation. Macrophage M0 polarization towards M1 or M2 was initiated at day 6 by addition of LPS and INF-γ, or IL-4 and IL-13, respectively. Results: E. faecalis did not inhibit macrophage differentiation and were identified within macrophages. Viability of the macrophages infected with E. faecalis prior to differentiation was enhanced, evidenced by apoptosis inhibition, as was expression of CD38 and IRF5 proteins, indicators of M1-like polarization. These M1-like macrophages expressed an aberrant cytokine mRNA profile, with reduction in inflammatory cytokines IL-1β and IL-12 and increase in regulatory cytokine IL-10. No changes in TNF-α or TGF-β1 were detected, compared with the control groups. This atypical M1-like phenotype was retained even upon stimulation with growth factors that normally trigger their development into M2 macrophages. Conclusions: These findings suggested that E. faecalis infection of bone marrow-derived stem cells during differentiation into macrophages induces an atypical M1-like phenotype associated with intracellular bacterial survival.
Authors: Michele W L Teng; Edward P Bowman; Joshua J McElwee; Mark J Smyth; Jean-Laurent Casanova; Andrea M Cooper; Daniel J Cua Journal: Nat Med Date: 2015-06-29 Impact factor: 53.440
Authors: Carmen Torres; Carla Andrea Alonso; Laura Ruiz-Ripa; Ricardo León-Sampedro; Rosa Del Campo; Teresa M Coque Journal: Microbiol Spectr Date: 2018-07