ABSTRACT
Objective To investigate the effect of Toll-like receptor 2(TLR2)on the proliferation of human keratinocytes.Methods Keratinocytes were isolated from the foreskin of children,and subjected to primary culture.Atier 3-5 passages.the kemtinocytes were incubated with various concentrations of peptidoglycan(PGN).a TLR2 agonist.Cell proliferation was detected by MTT colorimetric assay and the suitable concentrations of PGN were determined.The mRNA and protein expressions of Ki67.TLR2.NF-kB p65 and TGF-α were detected by real-time quantitative PCR and Western blot.respectively,in keratinocytes treated witll PGN of 0,1.25,2.5 and 5 μg/mL.Antibody blocking test was utilized to evaluate the effect of blocking TLR2 with specific anti-TLR2 neutralizing monoclonal antibody before incubation with PGN on the expressions of Ki67,TLR2,NF-KB p65 and TGF-α by keratinocytes.Results The proliferation of kemtinocytes was significantly promoted by the incubation with PGN of 1.25,2.5 and 5μg/mL for 24 hours (all P＜0.05),which also increased the expression of Ki67 protein,TLR2 mRNA and protein,and NF-KB p65 protein.Further more,the mRNA expression of Ki67 in keratinocytes was elevated bv PGN of 1.25 and 2.5μg/mL,the mRNA expression of NF-KB p65 elevated by PGN of 1.25μg/mL,and the expressions of TGF-αprotein and mRNA elevated by PGN of 1.25 and 5μg/mL (P＜0.05).The mRNA and protein expressions of Ki67,TLR2,NF-kB p65 and TGF-αwere all inhibited by the blocking of TLR2 before incubation with PGN (a11 P＜0.05).Conclusion Activation of TLR2 bv PGN could induce the over-proliferation of human keratinocytes,likely through promoting NF-rB activation and TGF-α expression.