Background: Glycogen synthase kinase 3 beta (GSK3b) is a multifunctional molecule, which plays a critical role in the regulation of various signaling pathways including cell proliferation, growth and development, and inflammation. However, whether GSK3b is involved in the pathological process of Pseudomonas aeruginosa keratitis remains unknown.
Methods: First, western blots were performed to measure the phosphorylated level of GSK3β at Ser9 (inactive form) in an animal model of Pseudomonas aeruginosa keratitis. Second, the keratitis model received the GSK3β inhibitor SB216763, and the inflammation of cornea was evaluated by clinical scores and slit photos. The expressions of inflammatory cytokines were assessed by real-time PCR, and the corneal bacterial burden was determined by plate count.
Results: The phosphorylated level of GSK3β at Ser9 in the cornea markedly decreased after Pseudomonas aeruginosa infection. The inhibition of GSK3β by SB216763 significantly ameliorated the progress of corneal disease and alleviated corneal opacity. SB216763 suppressed the expression of inflammatory cytokines IL-6 and IL-1b, but exhibited no effects on TNF-a and IL-10 expression. SB216763 dramatically decreased cornea bacterial burden at 5 days after infection with Pseudomonas aeruginosa.
Conclusions: The activity of GSK3b was enhanced in Pseudomonas aeruginosa keratitis. The inhibition of GSK3β by SB216763 promoted host resistance against Pseudomonas aeruginosa keratitis, via down regulating inflammatory cytokines and bacterial burden.