Toll-like Receptors Regulate MIF Expression in Benign Lymphoepithelial Lesion of the Lacrimal Gland

Abstract

Despite a perpetual increase in the prevalence of benign lymphoepithelial lesion, data on the mechanisms governing its pathogenesis are still missing. Thus, we aimed in the present study to evaluate whether TLRs could regulate the expression of the pleiotropic pro-inflammatory and tumor-related cytokine MIF in BLEL. Using gene expression profiling and protein expression analysis methods, we found that TLRs were overexpressed and that their signaling pathways were activated in BLEL. We have also confirmed in tissues biopsies, the overexpression of MIF reported previously in plasma of BLEL specimen. The analysis of the TLR7/8 impact on the expression of MIF in BLEL primary cells showed that when activated, TLR7/8 stimulate mainly BLEL lymphocytes to release MIF but not the fibroblast-like cells. No significant change was observed when MIF expression was investigated at the transcriptional level 24h post TLR7/8 activation. Taken together, these data suggest that TLR7 and TLR8 are activated in BLEL and may induce a cell type-dependent regulation of MIF secretion and expression.