Wnt pathway regulates IL-34 level in lupus nephritis.

OBJECTIVE: The aim of this study was to investigate the role of the Wnt pathway in regulating the IL-34 level of lupus nephritis (LN) patients, and to explore the underlying mechanism. MATERIALS AND METHODS: Human mesangial cells (HMCs) of LN patients were selected. The expression level of IL-34 was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) and Western blot, respectively. Subsequently, HMCs were treated with the Wnt pathway antagonist, DDK1. Meanwhile, the IL-34 level in DDK1 transfected HMCs was then detected. In addition, the viability of HMCs treated with DDK1 was detected by cell counting kit-8 (CCK-8) and colony formation assay, respectively. RESULTS: Both the mRNA and protein levels of IL-34 were significantly upregulated in HMCs of LN patients. Higher expression of ß-catenin was observed in HMCs of LN patients than those of controls, which was reduced after DDK1 treatment. Meanwhile, IL-34 level in HMCs of LN patients was significantly downregulated after DDK1 treatment. In addition, DDK1 treatment remarkably increased the proliferative ability and colony formation ability of HMCs in LN patients. CONCLUSIONS: IL-34 is highly expressed in HMCs of LN patients and is negatively regulated by the Wnt pathway. Furthermore, HMCs viability is remarkably enhanced after blocking the Wnt pathway.