LncRNA HOTAIR promotes renal interstitial fibrosis by regulating Notch1 pathway via the modulation of miR‐124

ABSTRACT Aim To understand the mechanism of long non‐coding RNA (LncRNA) HOTAIR on renal interstitial fibrosis (RIF) by regulating Notch1 pathway via the modulation of miR‐124. Methods Unilateral ureteral occlusion (UUO) was used to construct the RIF rat model. HK‐2 cells induced by TGF‐β1 were used for the in vitro experiment, which were divided into five groups: Vehicle, TGF‐β1, si‐HOTAIR+TGF‐β1, miR‐124 inhibitor+TGF‐β1, and si‐HOTAIR+miR‐124 inhibitor+TGF‐β1 groups. Quantitative real‐time PCR (qRT‐PCR) and Western blot were performed to detect the expression of HOTAIR, miR‐124, Notch1‐ and epithelial‐to‐mesenchymal transition (EMT)‐related proteins. Results Significant elevated HOTAIR and reduced miR‐124 were presented in UUO rats and TGF‐β1‐induced HK‐2 cells in a time‐dependent manner, with the increased Jagged1 (JAG1), Notch1, NICD, α‐SMA and FN, as well as the decreased E‐cadherin (all P < 0.05). Compared with the TGF‐β1 group, cells in the si‐HOTAIR+TGF‐β1 group were remarkably declined in cell proliferation and the protein expressions of JAG1, Notch1, NICD, α‐SMA, and FN, but dramatically higher in E‐cadherin expression (all P < 0.05). However, in comparison with the si‐HOTAIR+TGF‐β1 group, cells in the si‐HOTAIR+miR‐124 inhibitor+TGF‐β1 group were apparently improved in proliferation and the protein expression of JAG1, Notch1, NICD, α‐SMA, and FN, but substantially reduced in the level of E‐cadherin protein (all P < 0.05). Conclusion Silencing lncRNA HOTAIR can up‐regulate miR‐124 to block Notch1 pathway, and thereby alleviating EMT and RIF, indicating HOTAIR as a potential target for RIF treatment.