Terminal complement complex C5b-9 reduced megalin and cubilin-mediated tubule proteins uptake in a mouse model of trichloroethylene hypersensitivity syndrome

Abstract Trichloroethylene(TCE), a commonly used industrial solvent and degreasingagent, is known to cause trichloroethylenehypersensitivity syndrome (THS) with multi-system damage, including skin, liver and kidney. Clinical evidence have shown that the kidney injury occurs in THS and our previous studies suggested that the terminal complement complexC5b-9 deposited in impaired renal tubulesinduced by TCE with unclear mechanisms. In the present study, we questioned whether activation of the complement systemwith renal deposition of C5b-9 contributes to TCE-induced kidney injury in THS. We established a BALB/c mouse model of TCE sensitization with or without pretreatment of exogenous CD59, a C5b-9 inhibitory protein. H&E staining, PAS staining, and biochemical detectionof urinary proteins were performed to assess renal function. Deposition of C5b-9 and expression of CD59were evaluated by immunohistochemistry. Sub-lytic effects of C5b-9 in tubular epithelial cells were assessed by lactate dehydrogenase (LDH) cytotoxicity assay. Expression of endocytosis receptors megalin and cubilinon proximal tubuleswere assessed by immunofluorescence and qRT-PCR. We found that TCE sensitization induced structural and functional changes of renal tubulesin mice, associated with the deposition of sub-lytic C5b-9 on proximal tubular epithelial cells. TCE sensitization decreased proximal tubuleuptake of filtered proteins and renal expression of megalin and cubilin, phenotypes that were attenuated by pretreatment with exogenous CD59. Overall, our findings reveal a novel mechanism underlying sub-lytic C5b-9 acting on megalin and cubilin, contributes to the renal tubulesdamage by TCE exposure.