The Role Of Lipopolysaccharide In Nuclear Translocation Of IL-37b In Rheumatoid Arthritis Fibroblast-like Synoviocytes

[Objective] To explore the effects of lipopolysaccharide on the expression of IL-37 b,Smad3,caspase-1,NF-?B and the possible mechanisms of IL-37 b on signaling pathways of nuclear translation in RA.[Method] 1. Training the fibroblast-like synoviocytes in RA patients and osteoarthritis(OA) patients. RA-FLS and OA-FLS were treated with LPS, using RA-FLS and OA-FLS without LPS treatment as control. LPS was used at 100ng/ml. After LPS stimulated 12 h, the effect of LPS on expression of IL-37 b,Smad3, caspase-1,NF-?B m RNA were detected by real-time PCR respectively. 2. RA-FLS and OA-FLS were treated without LPS as controls. experimental groups were stimulated with LPS for 12 h. The levels of IL-37 b, Smad3, NF-?B protein were detected by Western blot. 3. The cells were divided into three groups. The first group: caspase-1 inhibitor was added 2h in RA-FLS before LPS stimulation, then stimulated by LPS for 12 h. The second group: RA-FLS and OA-FLS were stimulated with LPS for 12 h. The third group: as a control group, RA-FLS and OA-FLS without LPS treatment. Then the intracellular distribution of IL-37 b were detected by confocal laser scanning microscopy.[Results] 1. IL-37 b, Smad3, caspase-1,NF-?B mRNA was detected by RT-PCR. The expression of IL-37 b, Smad3, caspase-1, NF-?B m RNA increased gradually in RA-FLS treated with LPS. After RA-FLS was treated with LPS, the results of RT-PCR show that the expression of IL-37 b, Smad3, caspase-1, NF-?B m RNA were significantly increased(P<0.05) compared with OA-FLS which is also LPS-stimulated.2. Effect on the expression of IL-37 b, Smad3, NF-?B protein levels stimulated by LPS. After RA-FLS and OA-FLS were treated with LPS(100ng/ml) for 12 h, IL-37 b, Smad3, NF-?B protein were detected by Western blot. The results show that IL-37 b, Smad3, NF-?B protein expression were higher than control which is not stimulated by LPS, and the increased of protein levels is consistent with the m RNA level increased. 3. Effects on the intracellular distribution of IL-37 b stimulated by LPS. The intracellular distribution of IL-37 b were detected by confocal laser scanning microscopy, after the three groups were treated differently. The results show that the distribution of IL-37 b in nucleus is markedly increased than control which is not stimulated by LPS, after RA-FLS and OA-FLS were treated with LPS. The distribution of IL-37 b in nucleus is obviously increased in RA-FLS compared with OA-FLS which is also stimulated with LPS. After treated with caspase-1 inhibitor 2h before LPS-stimulation in RA-FLS, we observed that the nuclear staining was significantly reduced compared with the group without caspase-1 inhibitor treated. The distribution of IL-37 b in nucleus was low or least in RA-FLS and OA-FLS which were not stimulated by LPS.[Conclusion] LPS can promote the levels of IL-37 b m RNA and the expression of IL-37 b protein of RA-FLS, it also can accelerate the distribution of IL-37 b in the nuclear via upregulating the expression of caspase-1 and Smad3.