MALAT1 Promotes Cell Apoptosis and Suppresses Cell Proliferation in Testicular Ischemia-Reperfusion Injury by Sponging MiR-214 to Modulate TRPV4 Expression.

ABSTRACT

BACKGROUND/AIMS: Accumulating evidences has indicated that aberrant expression of long non-coding RNAs (lncRNAs) is tightly associated with the progression of ischemia-reperfusion injury (IRI). Previous studies have reported that lncRNA MALAT1 regulates cell apoptosis and proliferation in myocardial and cerebral IRI. However, the underlying mechanism of MALAT1 in testicular IRI has not been elucidated. METHODS: The levels of MALAT1, some related proteins and apoptosis in the testicular tissues were determined by quantitative real-time PCR, HE staining, immunohistochemistry, western blot and TUNEL assays. Relative expression of MALAT1, miR-214 and related proteins in cells were measured by western blot and quantitative real-time PCR. Cell viability and apoptosis were examined using MTT assay and flow cytometry. RESULTS: In the present study, we found that MALAT1 was up-regulated in animal samples and GC-1 cells. The expression level of MALAT1 was positively related to cell apoptosis and negatively correlated with cell proliferation as testicular IRI progressed. In gain and loss of function assays, we confirmed that MALAT1 promotes cell apoptosis and suppresses cell proliferation in vitro and in vivo. Furthermore, we found that MALAT1 negatively regulates expression of miR-214 and promotes TRPV4 expression at the post-transcriptional level. Consequently, we investigated the correlation between MALAT1 and miR-214 and identified miR-214 as a direct target of MALAT1. In addition, we found that TRPV4 acted as a target of miR-214. Over-expression of miR-214 efficiently abrogated the up-regulation of TRPV4 induced by MALAT1, suggesting that MALAT1 positively regulates the expression of TRPV4 by sponging miR-214. CONCLUSION: In sum, our study indicated that the lncRNA MALAT1 promotes cell apoptosis and suppresses cell proliferation in testicular IRI via miR-214 and TRPV4.