Article Impact Level: HIGH Data Quality: STRONG Summary of Nature Cardiovascular Research https://doi.org/10.1038/s44161-026-00798-3 Dr. Yao Wei Lu et al.
Points
- Researchers identified that the protein PCBP1 regulates the alternative splicing of the AARS2 gene to ensure proper mitochondrial function and energy production within developing heart muscle cells in newborn infants.
- Deletion of this critical gene in mouse models resulted in severe heart development abnormalities and postnatal lethality similar to the symptoms observed in human patients with congenital mitochondrial cardiomyopathy.
- The study found that a loss of proper gene splicing triggers a compensatory stress response pathway that further damages the heart by disrupting the vital process of oxidative phosphorylation.
- Laboratory tests using human induced pluripotent stem cells confirmed that switching off the PCBP1 gene reproduces the molecular hallmarks of the disease including impaired mitochondrial activity and cell death.
- These findings suggest that targeting the PCBP1-AARS2 regulatory axis could eventually provide a novel therapeutic strategy for treating various rare diseases affecting the heart, brain, and other vital organ systems.
Summary
This study evaluated the molecular mechanisms underlying AARS2-related infantile cardiomyopathy, a frequently fatal congenital condition characterized by mitochondrial dysfunction. While primary mutations in the alanyl-transfer RNA synthetase 2 (AARS2) gene are the known cause, the research sought to identify regulatory proteins that govern AARS2 transcript stability and splicing. Investigators utilized cardiomyocyte-specific deletion models in mice and lab-grown human induced pluripotent stem cells (iPSCs) to determine if the poly(rC)-binding protein 1 (PCBP1) acts as a critical mediator of cardiac mitochondrial homeostasis.
The analysis revealed that PCBP1 interacts directly with the AARS2 transcript to regulate its alternative splicing. Loss of PCBP1 in heart muscle cells caused premature termination of Aars2, resulting in significant heart development defects and postnatal lethality. Mechanistically, the disruption of the PCBP1-AARS2 axis led to a reduction in oxidative phosphorylation and the mitochondrial-encoded proteome. This breakdown triggered mitonuclear communication and the unfolded protein response (UPR) pathway, inducing a compensatory but ultimately maladaptive nuclear-encoded mitochondrial gene program similar to the phenotypes observed in human neonatal patients.
These findings suggest that PCBP1 is a vital genetic modifier that could serve as a novel therapeutic target for mitochondrial cardiomyopathies. By tracing the effects of PCBP1 deletion down to the molecular level, researchers demonstrated that restoring healthier AARS2 function through splicing regulation may avert lethal cardiac damage. Given that mitochondrial failure is a shared root cause across various rare disorders, this regulatory axis may have broader clinical relevance for treating mitochondrial diseases in the brain, lungs, and kidneys. Future studies will utilize the newly developed mouse models to evaluate pharmacological interventions aimed at stabilizing the PCBP1-AARS2 pathway.
Link to the article: https://www.nature.com/articles/s44161-026-00798-3
References
Lu, Y. W., Liang, Z., Dorr, K., Ruiz, S., Huang, X., Fangnibo Hanvi, D., Juntilla, S. M., Beutner, G., Lyu, S., Guo, H., Fernandes, T., Espinoza-Lewis, R. A., Wang, T., Li, K., Li, X., Bir Singh, G., Wang, Y., Deng, R., Cowan, D., … Wang, D.-Z. (2026). PCBP1 regulates alternative splicing of AARS2 in congenital cardiomyopathy. Nature Cardiovascular Research, 5(4), 328–350. https://doi.org/10.1038/s44161-026-00798-3
