Inhibiting effect of miR-18a on expression of extracellular matrix-related genes of NIH-3T3 by targeting Notch2

Abstract

BackgroundThe main pathological feature of silicosis is pulmonary fibrosis. Multiple miRNAs regulate the development of silicosis.ObjectiveUsing a fibroblast cell line, to explore the effect of miR-18a on the expression of extracellular matrix-related genes, and verify the mechanism.MethodsThe fibroblast cell line NIH-3T3 cells were transfected with miR-18a mimics or neurogenic locus notch homolog protein 2 (Notch2) small interfering RNA (siRNA). The mRNA expression changes of Acta2, Col1a1, and Notch2 were detected by real-time quantitative reverse transcription PCR (qRT-PCR), α-smooth muscle actin (α-SMA) and Notch2 were also detected at the protein level by Western blotting. To verify whether miR-18a could directly act on the complementary sequences of the Notch2 gene, human embryonic kidney HEK293T cells and the psiCHECKTM-2 vector were used.ResultsThe results of qRT-PCR showed that in NIH-3T3 cells, the over-expression of miR-18a mimics for 36 h inhibited the mRNA expression of Col1a1 and Acta2 (P<0.05). The results of Western blotting showed that the protein expression abundance of α-SMA was decreased at 48 h of miR-18a mimics over-expression. The qRT-PCR results showed that the over-expression of miR-18a for 36 h had no significant effect on Notch2 gene expression, but the Western blotting results showed that the over-expression of miR-18a mimics inhibited the expression of Notch2 at the protein level. The results of the dual luciferase reporter vector assay showed that in HEK293T cells, both over-expressed miR-18a mimics and inhibitors for 24 h demonstrated that Notch2 is a direct target gene of miR-18a. When Notch2 was inhibited for 36 h, the qRT-PCR results showed that Acta2 and Col1a1 were down-regulated (P < 0.05), and the results of Western blotting showed that α-SMA protein was also inhibited.ConclusionThe findings indicate that miR-18a could inhibit the expression of extracellular matrix-related genes of NIH-3T3 cells by directly acting on the 3’UTR of target gene Notch2.

Keywords

• silicosis
• microrna-18a
• neurogenic locus notch homolog protein 2