Mir-338-5P Involved In Antibody-mediated Renal Allograft Rejection By Targeting TRAF3Gene

Objective:The present study was to explore the serum miR-338-5p expression characteristics in renal transplant recipients, and its potential role on BAFF code.Methods:(1)Dual-Luciferase Reporter assay system was used to verify the target gene of miR-338-5p.(2)Sera of follow-up recipients were collected, and healthy volunteers were enrolled as controlled group. Serum miR-338-5p was detected by real-time PCR; Soluble BAFF was detected by ELISA; Titers of anti-HLA-I antibody, anti-HLA-Ⅱ antibody and anti-MICA antibody were detected by Luminex technology. Then correlation analysis between miR-338-5p, sBAFF and alloantibodies were taken.(3)In vitro experiment, the ability of tonsillar CD20+B cells to secrect IgG and IL-10was observed, after changing the expression level of miR-338-5p by its agonist or antagonist, and/or TRAF3siRNA interference, cocultured with anti-IgM antibody and/or recombinant human BAFF. SPSS17.0software was applied,t-test was used to compare the means of two independent samples; Paired samples t-test was used to compare the means of two paired samples; Spearman method and Pearson method were used to analyse the correlation; P<0.05was considered to be statistically significant.Results:(1)Dual-Luciferase Reporter Assay System verification results show that TRAF3and NF-κB1are all targeted by miR-338-5p, TRAF3is negatively regulated, but NF-κB1is positively regulated;(2)Compared with healthy controls, serum miR-338-5p in renal transplant recipients decreased significantly (P<0.001), while serum BAFF significantly increased (P<0.01). Serum miR-338-5p levels in recipients within1-yr post-transplantation were significantly lower than that of more than1-yr post-transplantation (P<0.01); Serum miR-338-5p levels in recipients within3-yr post-transplantation were significantly lower than that of more than3-yr post-transplantation (P<0.01);(3)As for all subjects, serum miR-338-5p was significantly negatively correlated with sBAFF (r=-0.51,P<0.001), and serum miR-338-5p was significantly negatively correlated with anti-HLA-Ⅱ antibody (r=-0.322,P<0.05); Serum miR-338-5p in recipients within3-yr was significantly negatively correlated with anti-HLA-Ⅱ antibody (r=-0.423,P<0.05), and serum miR-338-5p in recipients within3-yr was significantly negatively correlated with anti-MICA antibody(r=-0.411,P<0.05); Serum miR-338-5p in recipients more than3-yr was significantly positively correlated with anti-MICA antibody(r=0.486,P<0.05), and serum miR-338-5p in recipients more than3-yr was significantly positively correlated with anti-HLA&MICA antibody(r=0.578, P<0.01);(4)In vitro, miR-338-5p can enhance BAFF signal by targeting TRAF3, to significantly stimulate the secretion of IgG by CD20+B lymphocytes cocultured by BAFF and anti-μ antibody.Conclusion:miR-338-5p should be involved in renal allograft antibody-mediated rejection by targeting TRAF3and indirectly regulating BAFF signal, then affecting long-term outcome of renal allograft.