Role of microRNA-24 Transfection Mediated by Silica Nanoparticles in Apoptosis of Cardiomyocyte

Abstract

To explore the role of micro RNA-24 (miR-24) mediated by silica nanoparticles (SiNPs) modified by polyethyleneimine (PEI) on apoptosis of cardiomyocyte induced by H2O2, in this study, PEI was selected to modify the surface of SiNPs to obtain F-SiNPs, which were combined with miR-24 through electrostatic adsorption to form F-SiNPs-miR-24. Through characterization, the particle size, charge amount, and microstructure were studied. Then, the CCK-8 method was adopted to detect the toxicity of F-SiNPs on cardiomyocytes, and the cell uptake experiment was performed to analyze the transfection efficiency of F-SiNPs-miR-24 gene. There were 4 groups in vitro transfection experiment: the control group (A), the H2O2 group (B), the miR-24 inhibitor group (C), and miR-24 analog group (D). After that, RT-PCR was adopted to detect the expression of miR-24, Western blotting was used to detect the expression of target protein Bim, and the apoptosis of cardiomyocytes was analyzed by TUNEL staining. The results showed that the particle size of SiNPs was mainly distributed in the range of 40-60 nm, the mass ratio of SiNPs:DSP-PEI was 1:1, and the potential was 20.15 ±2.04 (mv) to construct functionalized nanoparticles. Cell uptake experiments showed that the gene transfection efficiency reached over 85%. In contrast with group A, the expression of miR-24 in B and C was obviously reduced, and that in D was obviously increased (P < 0.05). In contrast with group B, the expression of miR-24 in C was obviously reduced, and that in D was obviously increased (P < 0.05). The expression level of protein Bim in groups B and C was obviously higher than A (P < 0.05). In contrast with group A, the TUNEL-positive staining cells in C increased obviously and were bright green, while those in B were obviously reduced. In conclusion, the F-SiNPs formed after energetic modification have good biocompatibility and strong transfection ability, and their miR-24 transfection can inhibit H2O2-induced cardiomyocyte apoptosis and increase the survival rate of cardiomyocytes.