Effect of Dickkopf-1 regulated Wnt pathway on transdifferentiation of hypoxia-induced lens epithelial cells

Abstract

AIM: To scrutinize the role of the Wnt/β-catenin signaling pathway in the epithelial-mesenchymal transition(EMT)of lens epithelial cells under hypoxic conditions, and to further analyze the effect of Dickkopf-1(DKK-1)expression on EMT of lens epithelial cells.METHODS: Human lens epithelial cells(HLEB3 cells)were propagated in vitro and then separated into two groups: one exposed to standard oxygen levels, added DMEM culture solution containing 10% FBS(normoxic group)and another subjected to low oxygen levels(hypoxic group). The hypoxic condition was emulated by applying a concentration of 100 μmol/L cobalt chloride(CoCl2)for 6, 12, 24, and 48h. The utilization of immunofluorescence staining enabled the detection of Wnt3a and DKK-1 expressions, along with the expression and localization of β-catenin protein in these groups. The expression of DKK-1 mRNA was discerned by quantitative real-time polymerase chain reaction(qRT-PCR).RESULTS: Immunofluorescence assays indicated an escalating trend in the Wnt3a and DKK-1 protein expression, which corresponded with the increasing duration of hypoxia. Likewise, an intensified nuclear accumulation of β-catenin protein was observed to be directly proportional to the length of hypoxia treatment. The qRT-PCR demonstrated that the difference in DKK-1 mRNA expression between the normoxic group and the group exposed to hypoxia for 6h was not statistically significant(P>0.05), whereas the DKK-1 mRNA expression of the 12, 24, and 48h hypoxia groups were significantly increased(P<0.001).CONCLUSION: Hypoxia can activate Wnt/β-catenin pathway in lens epithelial cells and induce the expression of DKK-1, thus regulating the Wnt/β-catenin pathway and affecting the EMT process.

Keywords

• wnt/β-catenin signaling pathway
• dickkopf-1(dkk-1)
• hypoxia
• lens epithelial cells
• transdifferentiation