LIN28A regulates the let-7 miRNA–RALB axis in imMKCLs. (A) A schematic illustration depicting the let-7 miRNA–RALB axis regulating immune-related signaling, which alters the proliferation and platelet production capacity of imMKCLs. (B) LIN28A but not LIN28B shows increased expression in let-7^low cells compared to let-7^high cells. Bar graphs show TPM values of the indicated genes from 3 distinct imMKCL clones. (C) The lentiviral-mediated overexpression (O/E) of LIN28A significantly increased LIN28A and RALB messenger RNA (mRNA) expression while suppressing let-7a-5p expression. (D) Growth curve and relative fold change of the cell count on day 14 of MOCK and LIN28A O/E imMKCLs (clone 7). (E) LIN28A overexpression led to deficient iPSC-PLT generation by imMKCLs (clone 7). (F) Representative flow cytometry plots of iPSC-PLTs generated from MOCK or LIN28A O/E imMKCLs in static or turbulent flow conditions. CD41⁺CD42b⁺ platelets were identified from a platelet-sized gate. (G) LIN28A overexpression induced mRNA expression of representative immune-related genes in imMKCLs. Data are expressed as the mean ± standard error of the mean (SEM) from 3 to 4 independent experiments. Unpaired 2-tailed Student t tests were used to assess statistical significance. TPM, transcripts per kilobase million.