Epithelial cells of female genital tract mount a Type I Interferon response against Candida albicans

RODRIGUEZ EMILSE; MIRÓ MS; VIGEZZI C; ICELY PA; MACCIONI M; RIERA F; CAEIRO JP; SOTOMAYOR CE

Curitiba

Congreso; Xv Forum on fungal infection in the Clinical Practice INFOCUS 2017; 2017

INFOCUS

Introduction: Type I interferons (IFNs-I) constitute a family of pleiotropic cytokinesthat play a crucial role during infection by coordinating the function of different immunocompetent cells involved in the induction of defense against viruses and intracellular bacteria. However, recent studies have revealed that IFNs-I can also be producedin response to fungal pathogens, but their roles in antifungal immunity have not been thoroughly investigated. Candida albicans(Ca)is the most common human fungal pathogen causing both mucosal and systemic infections. Vulvovaginal candidiasis(VVC)is an acute inflammatory disease that affects 75% of women in reproductive age at least once in their lives. Nowadays, little is known about the ability of C.albicans to induce IFNs-I in female genital tract cells and the role of these cytokines during VVC.Objective: We aimed to study whether C.albicansrecognition can activate IFNs-I pathway in epithelial cells of female genital tract in order to establish a possible role during VVC. Methods:Human cervical epithelial cell line(HeLa) was stimulated withC.albicansSC5314 strainin three different conditions:Viable Infective(Ca)(fungus:cell ratio 0.25:1,0.5:1,1:1,5:1), viable Capseudomicelio(Amphotericin B-treated)(Capseudom)(5:1) andCaDNA(complexed with polyethylenimine)(CaDNA),during 4 and 24h. LPS and Poly I:C were used as activation controls. The expression of type IFNs-I pathway genes(IFN, IRF3, IRF7 and Mx1)was measured by qPCR and cytokine profile(IL1, IL6, TNF and TGF) by ELISA.Unstimulated cells were used as control.Results: We first evaluated the capacity ofHeLa cells to express IFNB mRNA in response to different stimuli. As expected, Poly I:C was able to induce a strong IFNB mRNA expression at 24h, while LPSshowed a significant increase at 4h(p<0.001). Interestingly, both Ca(0.25:1) andCapseudo (5:1) were able to induce an upregulatedIFN expression on epithelial cells at 4h(p<0.01) but only Capseudominduced high levels of this cytokine at 24h(p<0.05). Surprisingly, CaDNAdelivered into the cytoplasm of HeLa cells also induced higher IFNB mRNA levels when compared with unstimulated cells at 24h(p<0.05).Both viable Ca stimuli and activation controls induced high Mx1expression(a post-IFN Receptor gene). However, Mx1 levels were significantly higher at 24h compared to those observed at 4h(p<0,01).IRF3 and IRF7 expression was variable among the different stimuli.Moreover, Ca,CaDNA and Poly I:C induced high IL6 levels(p<0,001)while TNF and TGFB amounts were variable among the different stimuli, and IL1B remained undetectable.Conclusion:Our results provide novel and important evidence about the ability of different components of C.albicans to activate IFNs-I pathway in epithelial cells of female genital tract, highlighting the importance of IFNs-I in modulatingthe cytokine profile induced in response tothe invasion of this fungal pathogen. Thesefindings further expand the spectrum of immune mediators involved in the local response during VVC.