HOTAIR promotes myocardial fibrosis through regulating URI1 expression via Wnt pathway

To investigate whether HOX transcript antisense RNA (HOTAIR) regulates myocardial fibrosis via promoting proliferation of cardiac fibroblasts (CFs) and upregulating the expression levels of fibrotic proteins through activating Wnt signaling pathway.

The expression level of HOTAIR in Ang II-induced cardiac fibroblasts was detected by quantitative Real-time-polymerase chain reaction (qRT-PCR). Overexpression or knockdown of HOTAIR expression was achieved by lentivirus transfection. The effects of HOTAIR on regulating cell proliferation, migration and apoptosis were measured by cell counting kit-8 (CCK-8) test, transwell assay and flow cytometry, respectively. Western blot and qRT-PCR experiments were performed to detect expressions of fibrosis-related genes and Wnt pathway-related genes. Target gene of HOTAIR was predicted by bioinformatics analysis. Rescue assays were conducted to assess whether HOTAIR could regulate cell proliferation and fibrosis by activating Wnt signaling pathway via URI1.

QRT-PCR results showed that HOTAIR expression in Ang II-induced CF cells was significantly higher than that in control. HOTAIR overexpression in CF cells can promote cell proliferation and migration, inhibit apoptosis, and promote the expressions of fibrosis-related genes. Western blot results indicated that HOTAIR could upregulate URI1 expression and activate Wnt signaling pathway. In addition, rescue assay demonstrated that overexpression of URI1 reversed the inhibitory effect of HOTAIR knockdown on Wnt pathway.

Highly expressed HOTAIR promoted proliferation and migration of cardiac fibroblasts. HOTAIR remarkably upregulated fibrosis-related genes in CF cells. The mechanism of HOTAIR in regulating myocardial fibrosis might be related to the activation of Wnt signaling pathway through targeting URI1 expression.