TLR4 and Abnormal retinal morphology: Mechanistic investigation showed that the amelioration roles of retina-specific Irf8-deficiency for retinal diseases were ascribed to enhance the production of anti-inflammatory cytokines (IL-10, IL-27 and IL-35) and reduce the expression levels of pro-inflammatory IL-17 in the retina [51], while IRF8 was suggested as a downstream target gene of spleen tyrosine kinase (SYK) [54] and toll-like receptor (TLR)-4 was an adaptor protein of SYK [55] in the pathogenesis of ocular injuries.