Candida albicans infection leads to barrier breakdown and a MAPK/NF kB mediated stress response in the intestinal epithelial cell line C2BBe1
Intestinal epithelial cells (IEC) form a tight barrier to the gut lumen. Paracellular permeability of the intestinal barrier is regulated by tight junction proteins and can be modulated by microorganisms and other stimuli. The polymorphic fungus Candida albicans, a frequent commensal of the human mucosa, has the capacity of traversing this barrier and establishing systemic disease within the host. Infection of polarized C2BBe1 IEC with wild type C. albicans led to a transient increase of transepithelial electric resistance (TEER) before subsequent barrier disruption, accompanied by a strong decline of junctional protein levels and substantial, but considerably delayed cytotoxicity. Time resolved microarray based transcriptome analysis of C. albicans challenged IEC revealed a prominent role of NF kB and MAPK signalling pathways in the response to infection. Hence, we inferred a gene regulatory network based on differentially expressed NF kB and MAPK pathway components and their predicted transcriptional targets. The network model predicted activation of GDF15 by NF kB was experimentally validated. Furthermore, inhibition of NF kB activation in C. albicans infected C2BBe1 cells led to enhanced cytotoxicity in the epithelial cells. Taken together our study identifies NF kB activation as an important protective signalling pathway in the response of epithelial cells to C. albicans.
Cellular microbiology