Article Impact Level: HIGH Data Quality: STRONG Summary of Stem Cell Reports https://doi.org/10.1016/j.stemcr.2025.102757 Dr. Beatriz Gomes-Silva et al.
Points
- Analysis of alternative splicing during human cardiac development reveals that lab-grown heart cells often remain stuck in immature embryonic stages despite having a transcriptome that resembles prenatal cardiomyocytes.
- Researchers developed a comprehensive reference map that describes exactly how heart cells change throughout their development to help scientists determine if laboratory models are truly ready for clinical use.
- The study identified significant differences in fundamental cellular mechanisms where mis-splicing of essential factors prevents lab-grown cells from reaching the same functional level as those found in adult hearts.
- This new resource provides a catalog of splicing markers that allow for more rigorous assessment of cardiomyocyte maturation in studies focusing on heart disease mechanisms and drug development.
- By aligning laboratory models with the natural developmental trajectory of the human heart scientists can improve the reliability of precision cardiology research and the effectiveness of future therapeutic interventions.
Summary
This study, led by Maria Carmo-Fonseca and published in Stem Cell Reports, provides a comprehensive investigation into the maturation limitations of human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). While these laboratory-grown cells are essential for drug toxicity testing and disease modeling, they frequently exhibit immature phenotypic traits. Researchers utilized a temporal map of alternative splicing (AS) during native human cardiac development as a benchmark to assess how closely iPSC-CMs recapitulate the physiological transitions from early embryonic stages to adulthood.
The transcriptomic analysis revealed that while iPSC-CMs globally mirror the gene expression profiles of prenatal cardiomyocytes, their alternative splicing patterns remain highly heterogeneous. Specifically, certain splicing events in the lab-grown cells reflect early embryonic stages, whereas others more closely resemble late-stage fetal hearts. This molecular divergence suggests that iPSC-CMs often become arrested in a transitional state, failing to complete fundamental developmental steps necessary to reach the functional complexity of mature adult cardiac tissue.
Furthermore, the research identified significant mis-splicing of essential splicing factors within the iPSC-derived models, highlighting a breakdown in the coordination of genetic instructions. By establishing a catalog of specific splicing markers and a reference map of AS dynamics throughout heart development, the authors provide a rigorous framework for validating cardiomyocyte maturation in vitro. These findings offer a roadmap for correcting cellular deficiencies, potentially enhancing the reliability of precision cardiology and the development of more effective cardiovascular therapies.
Link to the article: https://www.cell.com/stem-cell-reports/fulltext/S2213-6711(25)00361-3?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2213671125003613%3Fshowall%3Dtrue
References
Gomes-Silva, B., Furtado, M., Ribeiro, M., Martins, S., Carvalho, T., Ventura-Gomes, A., Maatz, H., Parakkat, P., Crocini, C., Gotthardt, M., Savisaar, R., & Carmo-Fonseca, M. (2026). Alternative splicing dynamics during human cardiac development in vivo and in vitro. Stem Cell Reports, 102757. https://doi.org/10.1016/j.stemcr.2025.102757
