Fig. 4

Exosomal miR-216a-5p upregulation induced by DOX aggravates DOX-mediated cardiomyocyte pyroptosis. a Sequencing data of mouse plasma EXO miRNAs were used to identify miRNAs that were differentially expressed. The differentially expressed miRNAs are depicted in a volcano plot. b 4T1 cells were treated with DOX or DMSO, and upregulated exosomal miRNAs were identified by qRT‒PCR (n = 5). c Adult murine ventricular cardiomyocytes (AMVCs) were transfected with a miR-216a-5p mimic/scramble before being treated with DOX. Cell viability was determined by CCK-8 assays (n = 5). d Venn analysis revealed that miR-216a-5p satisfied two conditions. e–h miR-216a-5p knockdown and overexpression in cardiomyocytes were achieved through transfection with miR-216a-5p inhibitors and mimics, respectively. Multiple immunofluorescence stains and statistics were used to quantify AMVC and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) death. DAPI (blue), SYTOX (green), and α-actinin (red) (n = 5). Scale bar: 50 μm. i, j LDH release levels and cell viability were measured (n = 5). k–n The protein expression levels of NLRP3, GSDMD-N, cleaved CASP1, and cleaved IL-1β were detected via Western blotting (n = 5) (one-way ANOVA was used to compare all experimental groups with the DOX+miR NC group). “BCCs” indicates breast cancer cells, “ns” indicates non-significant, and “DOX” indicates doxorubicin. Data are presented as means ± SD