Proteomics to study cardiotoxic noxae in adults

The heart tissue is a potential target of various noxae contributing to the onset of cardiovascular diseases. However, underlying pathophysiological mechanisms are largely unknown. Human stem cell-derived models are promising, but a major concern is the cell immaturity when estimating risks for adults. In this study, 3D aggregates of human embryonic stem cell-derived cardiomyocytes were cultivated for 300 days and characterized regarding degree of maturity, structure, and cell composition. Furthermore, effects of ionizing radiation (X rays, 0.1–2 Gy) on matured aggregates were investigated, representing one of the noxae that are challenging to assess. Video-based functional analyses were correlated to changes in the proteome after the irradiation. Cardiomyocytes reached maximum maturity after 100 days in cultivation, judged by α-actinin lengths, displayed typical multinucleation and branching. At this time, aggregates contained all major cardiac cell types, proven by the patch-clamp technique. Matured and X-ray-irradiated aggregates revealed a subtle increase in beat rates and decrease in rhythmicity in a dose-dependent manner compared to non irradiated sham controls. The proteome analysis provides first insights into signaling mechanisms contributing to cardiotoxicity. Here, we propose an in vitro model suitable to screen various noxae to target adult cardiotoxicity by preserving all benefits of a 3D tissue culture.

心脏组织是多种有害因素的潜在作用靶点，这些因素可诱发心血管疾病发作。然而，其潜在的病理生理机制目前尚未完全阐明。人类干细胞衍生模型具有良好应用前景，但在评估成人疾病风险时，细胞成熟度不足是其主要局限。本研究中，研究人员对人类胚胎干细胞衍生的心肌细胞（cardiomyocytes）三维聚集体进行了300天的体外培养，并对其成熟度、结构及细胞组成进行表征。此外，本研究还探究了电离辐射（X射线，0.1~2 Gy）对成熟聚集体的影响——电离辐射属于难以评估的有害因素之一。研究人员将基于视频的功能分析结果与辐照后蛋白质组的变化进行关联分析。通过α-辅肌动蛋白（α-actinin）的长度评估可知，培养100天后心肌细胞达到最大成熟度，呈现典型的多核化与分支形态。此时，经膜片钳技术（patch-clamp technique）验证，聚集体包含所有主要的心脏细胞类型。与未辐照的假处理对照组相比，成熟并经X射线辐照的聚集体表现出搏动速率小幅升高，且节律性呈剂量依赖性降低。蛋白质组分析为阐明介导心脏毒性的信号通路提供了初步见解。本研究提出了一种适合筛选多种有害因素的体外模型，该模型通过保留三维组织培养的所有优势，可用于成人心脏毒性的相关评估。