A quantitative proteomic study identifies Dectin-1 activation by Candida albicans or curlan as relevant in type-I interferon pathway induction in epithelial cells of the female genital tract

RODRIGUEZ, E; ANGIOLINI, S; ICELY, P; HERNANDEZ, ML; STEMPIN, CC; GIL GARCÍA, C; SOTOMAYOR, C

San Luis

Congreso; LXXI Reunión Científica Anual de la Sociedad Argentina de Inmunología.; 2023

Sociedad Argentina de Inmunología.

Vulvovaginal candidiasis (VVC) is primarily caused by Candida albicans (Ca),impacting over 75% of healthy women at least once in their lifetime. Despiteextensive knowledge about host predisposing factors, many mechanisms andimmune mediators involved in the Ca-Epithelial Cell (EC) interaction are unclear.In particular, the role of type I interferons (IFN-I) during fungal infections is notwell understood. The activation of the Dectin1 receptor by Ca β-glucans and thesubsequent induction of IFNβ production in dendritic cells have been documentedduring systemic candidiasis, but its exact role in EC of the female genital tract(FGT) remains unknown. Objective: To study the biological processes andcellular pathways differentially regulated in EC of the FGT after interaction withCa and the Dectin1 agonist, Curdlan, through a label-free quantitative proteomicstudy. Methods: We performed an in vitro model of VVC using the human ECline, HeLa. A quantitative proteomic approach using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) was performed to study the changes inthe abundance of EC proteins after interaction with Ca SC5314 (5:1 Ca:cell ratio)or Curdlan (100 μg/mL) during 4h. Unstimulated EC were considered as control.Four biological replicates of each condition were analyzed. The bioinformaticsanalysis of differentially regulated proteins (DRPs) was carried out using GeneOntology and REVIGO for GO terms enrichment analysis and Reactome forpathways analysis. Results: A total of 216 DRPs upon Ca interaction wereobserved in EC (95 upregulated and 121 downregulated). GO term enrichmentanalysis showed that the more abundant proteins were mainly involved innucleocytoplasmic transport, regulation of metabolism, and immune response.Pathway enrichment analysis of proteins upregulated after Ca stimulationconfirmed “Antiviral mechanism by IFN-stimulated genes” (p=9.9e-7) as the mostrelevant pathway in response to Ca. Furthermore, other relevant pathways wereclosely related to IFN-I signaling mechanisms such us “ISG15 antiviralmechanisms” (p=5.8e-6) and “Interferon signaling” (p=3.5e-3). On the other hand,429 DRPs were identified in EC stimulated with the β-glucan Curdlan compared tocontrol (252 upregulated and 177 downregulated). GO term analysis showed thatthe most abundant proteins were involved in biological processes related tonucleocytoplasmic transport, metabolic process, viral process, and geneexpression. Interestingly, the pathway “Antiviral mechanisms by IFN- stimulatedgenes” (p=2.6E-5) was among the 10 most relevant pathways as in ECinteracting with Ca. Conclusion: This study provides significant evidence aboutthe activation of the IFN-I pathway in EC of the FGT in response to Ca infection.Our results also suggest that the regulation of this pathway could involve theactivation of the Dectin1 receptor by Ca β-glucans. Taken together, quantitativeproteomics offered new insights into fungal-host interaction during VVC.