The role of Syk signaling in antifungal innate immunity of human corneal epithelial cells.

Ying Liu,Cui Li,Qian Wang,Liting Hu,Qing Li,Guiqiu Zhao,Jing Lin,Chengye Che

doi:10.1186/s12886-015-0041-z

Abstract

BackgroundFungal keratitis is a kind of intractable and sight-threatening diseases. Spleen-tyrosine kinase (Syk) is a non-receptor tyrosine kinase, which plays an important role in the signaling pathway of the receptors. In the current study, we investigate the expression and function of Syk in human corneal epithelial cells with Aspergillus fumigatus (A. fumigatus) infection.MethodsCultured telomerase-immortalized human corneal epithelial cells (THCEs) were treated with A. fumigatus hyphae with or without treatment of Syk inhibitors. Activation of Syk and the role of Syk in regulating inflammatory cytokines and chemokines expression were evaluated. The mRNA expression was determined by real time PCR, and protein activation was measured by western blotting.ResultsSyk protein was detected in THCEs, and its activation was enhanced after treatment of A. fumigatus hyphae. Expression of inflammatory cytokines (IL-1β and IL-6) and chemokines (IL-8 and CXCL1) mRNA were significantly increased after stimulation of A. fumigatus hyphae in THCEs. Activation of Syk and expression of IL-1β, IL-6, IL-8 and CXCL1 by A. fumigatus hyphae were blocked by Syk inhibitors.ConclusionThese findings demonstrate that normal human corneal epithelial cells produce Syk, and Syk activation plays an important role in regulating A. fumigatus hyphae-induced inflammatory responses in THCEs.

Highlights

Fungal keratitis is a kind of intractable and sight-threatening diseases
A. fumigatus hyphae stimulated the expression of inflammatory mediators in telomerase-immortalized human corneal epithelial cells (THCEs) To explore inflammatory response of THCEs stimulated by A. fumigatus hyphae (5 × 106/mL), the mRNA expression of inflammatory cytokines (IL-1β and IL-6) and chemokines (IL-8 and CXCL1) in THCEs were evaluated by qPCR at 4, 8, 16 h
IL-1β (p < 0.01, p < 0.01, p < 0.01), IL-6 (p < 0.05, p < 0.01, p < 0.01), IL-8 (p < 0.01, p < 0.01, p < 0.01) and CXCL1 (p < 0.05, p < 0.01, p < 0.01) mRNA levels were elevated after the A. fumigatus hyphae stimulation of 4, 8, 16 h compared with untreated normal THCEs

Summary

Introduction

Fungal keratitis is a kind of intractable and sight-threatening diseases. We investigate the expression and function of Syk in human corneal epithelial cells with Aspergillus fumigatus (A. fumigatus) infection. Fungal keratitis is a corneal ulcer disease caused by the infection of pathogenic fungi [1]. There is a highly conservative consensus sequence named as pathogen associated molecular patterns (PAMPs) on the fungi. After the invasion of fungi, the innate immune response can immediately identify the PAMPs by pattern recognition receptors (PRRs). PRRs is the first defense line to identify and resist the pathogen infections. It mediates the adhesion, absorption and eradication of pathogen [2]. The PRRs that participate in the immune response of fungi mainly include Toll-like receptors (TLRs), C-type lectin receptors (CLRs) and nucleotide-binding oligomerization domain-like receptors (NLRs) [3]

Methods

Results

Discussion

Conclusion