EGR1 Regulates Oral Epithelial Cell Responses to Via the EGFR- ERK1/2 Pathway

is a fungal pathobiont colonising mucosal surfaces of the human body, including the oral cavity. Under certain predisposing conditions, invades mucosal tissues activating EGFR-MAPK signalling pathways in epithelial cells via the action of its peptide toxin candidalysin. However, our knowledge of the epithelial mechanisms involved during colonisation is rudimentary. Here, we describe the role of the transcription factor early growth response protein 1 (EGR1) in human oral epithelial cells (OECs) in response to . EGR1 expression increases in OECs when exposed to independently of fungal viability, morphology, or candidalysin release, suggesting EGR1 is involved in the fundamental recognition of rather than in response to invasion or 'pathogenesis'. Upregulation of EGR1 is mediated by EGFR via Raf1, ERK1/2 and NF-κB signalling but not PI3K/mTOR signalling. Notably, EGR1 mRNA silencing impacts on anti- immunity, reducing GM-CSF, IL-1α and IL-1β release, and increasing IL-6 and IL-8 production. These findings identify an important role for EGR1 in priming epithelial cells to respond to subsequent invasive infection by and elucidate the regulation circuit of this transcription factor after contact.