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

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-beta 1 were used for the in vitro experiment, which were divided into five groups: Vehicle, TGF-beta 1, si-HOTAIR+TGF-beta 1, miR-124 inhibitor+TGF-beta 1, and si-HOTAIR+miR-124 inhibitor+TGF-beta 1 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-beta 1-induced HK-2 cells in a time-dependent manner, with the increased Jagged1 (JAG1), Notch1, NICD, alpha-SMA and FN, as well as the decreased E-cadherin (all P < 0.05). Compared with the TGF-beta 1 group, cells in the si-HOTAIR+TGF-beta 1 group were remarkably declined in cell proliferation and the protein expressions of JAG1, Notch1, NICD, alpha-SMA, and FN, but dramatically higher in E-cadherin expression (all P < 0.05). However, in comparison with the si-HOTAIR+TGF-beta 1 group, cells in the si-HOTAIR+miR-124 inhibitor+TGF-beta 1 group were apparently improved in proliferation and the protein expression of JAG1, Notch1, NICD, alpha-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.