Search

Objective To investigate the regulatory effect of tRNA-derived small RNA (tsRNA) on ferroptosis in mouse cardiomyocytes and its mechanism. Methods RT-qPCR was used to measure the relative expression level of 5'tRF-LysCTT in the heart, liver, spleen, kidney, brain, and muscle of C57BL/6J mice aged 8 weeks. Primary cultured cardiomyocytes were divi-ded into groups A, B, C, and D: the cardiomyocytes in group A were cultured in a complete medium for 60 h; those in group B were cultured in a complete medium for 24 h, followed by starvation treatment for 12 h and H/R treatment for 24 h; those in groups C and D were transfected with antagomir-NC and antagomir-5'tRF-LysCTT, respectively, and were given starvation treatment (12 h) and H/R treatment (12 h) after 24 h of transfection. Primary cultured cardiomyocytes were divided into groups E, F, and G: the cardiomyocytes in group E were cultured in a complete medium for 24 h; those in group F were transfected with agomir-NC for 24 h; those in group G were transfected with agomir-5'tRF-LysCTT for 24 h. RT-qPCR was used to measure the relative expression levels of 5'tRF-LysCTT, Ptgs2, Gpx4, and Slc7a11 in mouse cardiomyocytes of groups A-G; ferrous ion colorimetric test kit, lipid reactive oxygen species (ROS) staining, and CCK8 assay kit were used to measure the relative content of ferrous ions, ROS level, and the survival rate of cardiomyocytes in groups A-G; Prussian blue staining was used to observe iron ion deposition in cardiomyocytes. Results RT-qPCR showed that the expression level of 5'tRF-LysCTT in heart was significantly higher than that in the liver, spleen, kidney, brain, and muscle (F=16.21,t=3.81-7.93,P0.05). Compared with group E, group G had significant increases in the relative expression levels of 5'tRF-LysCTT and Ptgs2, significant reductions in the relative expression levels of Gpx4 and Slc7a11, significant increases in the relative content of ferrous ions and ROS level, and a significant reduction in the survival rate of cardiomyocytes (t=3.57-91.84,P0.05). Conclusion 5'tRF-LysCTT can regulate ferroptosis in mouse cardiomyocytes, and knockdown of 5'tRF-LysCTT can inhibit cardiomyocyte ferroptosis induced by H/R, while overexpression of 5'tRF-LysCTT can promote cardiomyocyte ferroptosis.

Objective To investigate the regulatory effect of 3'-tRF-PheGAA on angiotensin Ⅱ (Ang Ⅱ)-induced cardiomyocyte hypertrophy and its mechanism. Methods Primary cardiomyocytes of neonatal mice were obtained and cultured for 24 h, and were then divided into groups A to G. The cardiomyocytes in group A were cultured with DMEM/F12 complete culture medium for 36 h. The cardiomyocytes in group B were transfected with negative control (NC) for 36 h. The cardiomyocytes in group C were transfected with agomir-3'-tRF-PheGAA for 36 h. The cardiomyocytes in group D were cultured with DMEM/F12 complete culture medium for 84 h. The cardiomyocytes in group E were treated with Ang Ⅱ at a final concentration of 1 μmol/L for 48 h. The cardiomyocytes in group F were transfected with anta-NC for 36 h and then treated with Ang Ⅱ at a final concentration of 1 μmol/L for 48 h. The cardiomyocytes in group G were transfected with anta-3'-tRF-PheGAA for 36 h and then treated with Ang Ⅱ at a final concentration of 1 μmol/L for 48 h. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to determine the gene expression levels of 3'-tRF-PheGAA, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and β-myosin heavy chain (β-MHC) in the cardiomyocytes in each group. Rhodamine-labeled phalloidin was used to stain F-actin in the cardiomyocytes in each group and calculate the skeletal surface area of cardiomyocytes. Results The RT-qPCR results showed significant differences between groups A to C in the gene expression levels of 3'-tRF-PheGAA, ANP, BNP, and β-MHC in cardiomyocytes (F=137.10-1 061.00,P