Fig. 6

Corneal stromal fibroblasts are activated to produce IL-6 by TLR2 stimulation. A, B Representative flow cytometry cytograms (A) and quantitative analysis of TLR2, TLR3 and TLR4 in human keratocytes with or without 0–100 ng/mL of Pam2CSK4 treatment for 24 h. C Real-time RT-PCR for IL-6 in human keratocytes after Pam2CSK4 treatment and ELISA for IL-6 in the supernatant of primary human keratocytes. The mRNA levels are presented as fold changes relative to the levels in cells without Pam2CSK4 stimulation. D Schematic of proposed signaling pathway through which sterile injury leads to corneal nerve damage and homeostatic regulation limits corneal nerve loss. The data are presented in mean values ± SD, where each circle depicts data from an individual biological sample. ***p < 0.001, ****p < 0.0001, as analyzed by one-way ANOVA and Tukey’s multiple-comparison test