Periostin deletion suppresses late-phase response in mouse experimental allergic conjunctivitis

Abstract Background To investigate the potential roles of periostin (POSTN), an extracellular matrix preferentially expressed in Th2-skewed conditions in the pathophysiology of allergic conjunctivitis. Methods The roles of POSTN in ragweed-induced experimental allergic conjunctivitis (RW-EAC) were evaluated using both POSTN-knockout (KO) and congenic BALB/c wild-type mice. Histological analysis was carried out to enumerate eosinophils/basophils in the conjunctival tissue. Th2 cytokine expression was evaluated by quantitative polymerase chain reaction (Q-PCR), and microarray analysis was performed to elucidate genes differentially expressed in POSTN-KO and wild-type mice in the RW-EAC model. Results Upregulation of POSTN expression and eosinophil infiltration was observed in subconjunctival tissue of RW-EAC in the wild-type mice. The number of infiltrating eosinophils in the conjunctivae of RW-EAC was diminished in POSTN-KO mice compared to wild-type mice. Q-PCR analysis of conjunctival tissue showed induction of Th2 cytokine ( Ccl5 , Il4 , Il5 , Il13 ) expression in the RW-EAC and attenuated Ccl5 , Il4 , Il1 3 mRNA expression in the conjunctivae of the RW-EAC using POSTN-KO mice. Microarray analysis and immunohistochemical analysis showed diminished basophil marker ( Mcpt8 ) expression and reduced numbers of infiltrating basophils in the conjunctivae of RW-EAC in POSTN-KO mice. Conclusions POSTN expression in conjunctival tissue plays an indispensable role in the late-phase reaction of the RW-EAC model by facilitating eosinophil/basophil infiltration and augmenting Th2 cytokine expression.