We recently achieved the first-in-human transfusion of induced pluripotent stem cell-derived platelets (iPSC-PLTs) as an alternative to standard transfusions, which are dependent on donors and therefore variable in supply. However, heterogeneity characterized by thrombopoiesis-biased or immune-biased megakaryocytes (MKs) continues to pose a bottleneck against the standardization of iPSC-PLT manufacturing. To address this problem, here we employ microRNA (miRNA) switch biotechnology to distinguish subpopulations of imMKCLs, the MK cell lines producing iPSC-PLTs. Upon miRNA switch-based screening, we find imMKCLs with lower let-7 activity exhibit an immune-skewed transcriptional signature. Notably, the low activity of let-7a-5p results in the upregulation of RAS like proto-oncogene B (RALB) expression, which is crucial for the lineage determination of immune-biased imMKCL subpopulations and leads to the activation of interferon-dependent signaling. The dysregulation of immune properties/subpopulations, along with the secretion of inflammatory cytokines, contributes to a decline in the quality of the whole imMKCL population.

我们最近首次实现了诱导多能干细胞衍生血小板 (iPSC-PLT) 的人体输注，作为标准输血的替代方案，标准输血依赖于捐赠者，因此供应量存在差异。然而，以血小板生成偏向或免疫偏向巨核细胞 (MK) 为特征的异质性仍然是 iPSC-PLT 制造标准化的瓶颈。为了解决这个问题，我们在这里采用 microRNA (miRNA) 开关生物技术来区分 imMKCL 的亚群，imMKCL 是产生 iPSC-PLT 的 MK 细胞系。基于 miRNA 开关的筛选，我们发现具有较低 let-7 活性的 imMKCL 表现出免疫偏差的转录特征。值得注意的是，let-7a-5p 的低活性导致 RAS 样原癌基因 B ( RALB ) 表达上调，这对于免疫偏向的 imMKCL 亚群的谱系确定至关重要，并导致干扰素依赖性信号传导的激活。免疫特性/亚群的失调以及炎症细胞因子的分泌导致整个 imMKCL 群体质量的下降。