Wu Xian, Williams Savanna, Robidoux Jacques, Sriramula Srinivas, Abdel Abdel-Rahman
Department of Pharmacology and Toxicology, East Carolina University, Greenville, NC, 27834, United States.
Toxicol Sci. 2025 Aug 12. doi: 10.1093/toxsci/kfaf115.
Cardiac organoids provide an in vitro platform for studying heart disease mechanisms and drug responses. However, a major limitation is the immaturity of cardiomyocytes, restricting their ability to mimic adult cardiac physiology. Additionally, the inadequacy of commonly used extracellular matrices (ECM), which fail to replicate the biochemical and mechanical properties of natural heart tissue, poses significant challenges. Consequently, structural integrity in cardiac organoids is impaired. Moreover, scalability remains an obstacle, as conventional ECM substitutes hinder mass production of organoids for high-throughput toxicology screening. To overcome these challenges, we developed an advanced model promoting fibroblast-driven ECM self-secretion, enabling physiologically relevant tissue architecture and function. Using the ECM-free, mature cardiomyocyte-integrated organoid model, we investigated the cardiotoxicity of doxorubicin, a widely used chemotherapeutic agent known to impair cardiac function. Cardiomyocytes derived from induced pluripotent stem cells were characterized for maturity by immunostaining for cTNT and MYL2 alongside gene expression analysis. Organoids treated with doxorubicin showed reduced size and increased collagen deposition. These structural changes correlated with functional impairments, including decreased beating rate and disrupted synchronous beating. In 2D culture, exposure to doxorubicin induced fibroblast activation, promoted early molecular signatures of endothelial-to-mesenchymal transition in endothelial cells, and triggered cytotoxic effects in cardiomyocytes. This study highlights the importance of ECM remodeling in advancing cardiac organoid models and demonstrates its potential for more accurate cardiotoxicity assessment. Addressing these limitations enhances the physiological relevance of cardiac organoid systems for drug safety assessment and cardiac disease modeling.
心脏类器官为研究心脏病机制和药物反应提供了一个体外平台。然而，一个主要限制是心肌细胞的不成熟，这限制了它们模拟成年心脏生理学的能力。此外，常用的细胞外基质（ECM）存在不足，无法复制天然心脏组织的生化和机械特性，这带来了重大挑战。因此，心脏类器官的结构完整性受到损害。此外，可扩展性仍然是一个障碍，因为传统的ECM替代物阻碍了用于高通量毒理学筛选的类器官的大规模生产。为了克服这些挑战，我们开发了一种先进的模型，促进成纤维细胞驱动的ECM自分泌，从而实现生理相关的组织结构和功能。使用无ECM、整合成熟心肌细胞的类器官模型，我们研究了阿霉素的心脏毒性，阿霉素是一种广泛使用的化疗药物，已知会损害心脏功能。通过对cTNT和MYL2进行免疫染色以及基因表达分析，对源自诱导多能干细胞的心肌细胞的成熟度进行了表征。用阿霉素处理的类器官显示尺寸减小和胶原蛋白沉积增加。这些结构变化与功能损害相关，包括跳动率降低和同步跳动紊乱。在二维培养中，暴露于阿霉素会诱导成纤维细胞活化，促进内皮细胞向间充质转化的早期分子特征，并引发心肌细胞的细胞毒性作用。这项研究强调了ECM重塑在推进心脏类器官模型方面的重要性，并证明了其在更准确的心脏毒性评估中的潜力。解决这些限制可提高心脏类器官系统在药物安全性评估和心脏病建模方面的生理相关性。
