Activation of the lectin complement pathway on human renal glomerular endothelial cells triggered by high glucose and mannose-binding lectin

Abstract

This study aimed to investigate the roles of high glucose and mannose-binding lectin (MBL) on the activation of the lectin complement pathway (LCP) on human renal glomerular endothelial cells (HRGECs) in vitro. Flow cytometry analysis, immunofluorescence staining and Western blot were used to detect the cell surface deposition of MBL, C3 and the membrane attack complex (MAC), as well as the code position of MBL and C3 (MBL+C3). Electrophoretic mobility shift assay (EMSA) was used to measure the activation of nuclear factor-kappaB (NF-κB). These results show that cell surface deposition of MBL, C3 and MBL+C3 after exposure to high glucose increased in both time- and dosedependent manner (P < 0.05). Moreover, MBL, C3 and MBL+C3 deposition stimulated by exogenous recombinant human MBL (rhuMBL) were also observed in both time- and dose-dependent manner, peaking at 4 h and then decreasing (P < 0.05). Inhibition experiments indicated that the inhibitory monoclonal antibody 3F8 against human MBL (MAb 3F8) significantly abrogated the cell surface deposition of MBL, C3 and MBL+C3, attenuated MAC staining, and inhibited NF-κB activation in HRGECs (P < 0.05). In conclusion, high glucose and MBL played an important role on the LCP activation of HRGECs, and MAb 3F8 may represent a novel potential therapeutic strategy to block LCP activation on HRGECs.

Key words: High glucose, mannose-binding lectin, complement activation, human renal glomerular endothelial cells.