LOX-1 is involved in IL-1beta production and extracellular matrix breakdown in dental peri-implantitis.

PURPOSE: To explore whether lectin-type oxidized LDL receptor 1 (LOX-1), interleukin 1 beta (IL-1beta), matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9) are involved in the nosogenesis of human dental peri-implantitis and determine the role of LOX-1 in IL-1beta, MMP2 and MMP9 production in response to Porphyromonas gingivalis. METHODS: Peri-implant crevicular fluid (PICF) was collected from ten patients with healthy implants and ten patients with peri-implantitis. The LOX-1 protein in PICF was detected by Western-blot, and the expression of LOX-1 in superficial gingiva of peri-implantitis patients was detected by immunofluorescence staining. The IL-1beta, MMP2 and MMP9 proteins in PICF were detected by enzyme-linked immunosorbent assay (ELISA). THP-1 macrophages were pretreated with neutralizing antibody (LOX-1) and inhibitors (LOX-1 and c-Jun N-terminal kinase, JNK) to evaluate the role of LOX-1 and JNK in IL-1beta production, as well as the role of LOX-1 in MMP2 and MMP9 production in response to P. gingivalis by quantitative polymerase chain reaction (RT-PCR) and Western-blot. RESULTS: LOX-1, IL-1beta, MMP2 and MMP9 increased in PICF of peri-implantitis patients and in THP-1 macrophages on P. gingivalis stimulation. IL-1beta, MMP2 and MMP9 production in response to P. gingivalis in THP-1 macrophages was dependent on LOX-1. JNK was responsible for LOX-1 induced IL-1beta production as a result of P. gingivalis infection. CONCLUSION: LOX-1 is involved in IL-1beta production and extracellular matrix breakdown is a novel inflammatory pathway trigger and potential drug target in human dental peri-implantitis.