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Updated: Jun 23, 2025
Author Spotlight: Effect of Left Atrial Ligation on Avian Embryonic Hearts and HLHS Implications
Published on: June 16, 2023
Molecular Pathways and Animal Models of Hypoplastic Left Heart Syndrome
Hisato Yagi1, Xinxiu Xu1, George C Gabriel1
1Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Insights
Hypoplastic left heart syndrome (HLHS) is a severe congenital heart defect. New research using stem cells reveals cell proliferation defects and Hippo-YAP signaling disturbances, suggesting novel prenatal therapies for improved left ventricular growth.
Area of Science:
- Developmental Biology
- Cardiovascular Research
- Genetics
Background:
- Hypoplastic left heart syndrome (HLHS) is a critical congenital heart defect characterized by underdeveloped left-sided heart structures.
- While surgical palliation has improved survival, high morbidity and mortality persist, necessitating better understanding of developmental etiology.
- Hemodynamic compromise and genetic factors are implicated in HLHS pathogenesis.
Purpose of the Study:
- To investigate the cellular and molecular mechanisms underlying left ventricular hypoplasia in HLHS.
- To explore the potential for prenatal interventions by gaining mechanistic insights into HLHS development.
- To identify novel therapeutic targets for HLHS.
Main Methods:
- Utilized induced pluripotent stem cell (iPSC)-derived cardiomyocytes from HLHS patients and mouse models.
- Analyzed cell proliferation, cell cycle progression (metaphase arrest), and signaling pathways.
- Investigated the role of Hippo-YAP signaling and epigenetic regulation in left-right patterning.
Main Results:
- Identified significant cell proliferation defects in HLHS cardiomyocytes.
- Observed disturbances in Hippo-YAP signaling and metaphase arrest.
- Found evidence suggesting epigenetic perturbation of left-right patterning pathways contributes to ventricular hypoplasia.
Conclusions:
- Cellular defects, including proliferation issues and altered Hippo-YAP signaling, are key to HLHS.
- Epigenetic dysregulation may underlie the left-sided restriction in ventricular development.
- Findings support novel prenatal therapeutic strategies targeting Hippo-YAP and epigenetic pathways.
Abstract:
Hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease (CHD) with underdevelopment of left-sided heart structures. While previously uniformly fatal, surgical advances now provide highly effective palliation that allows most HLHS patients to survive their critical CHD. Nevertheless, there remains high morbidity and mortality with high risk of heart failure. As hemodynamic compromise from restricted aortic blood flow has been suggested to underlie the poor LV growth, this suggests the possibility of prenatal fetal intervention to recover LV growth. As such interventions have yielded ambiguous results, the optimization of therapy will require more mechanistic insights into the developmental etiology for HLHS. Clinical studies have shown high heritability for HLHS, with an oligogenic etiology indicated in conjunction with genetic heterogeneity. This is corroborated with the recent recovery of mutant mice with HLHS. With availability-induced pluripotent stem cell (iPSC)-derived cardiomyocytes from HLHS mice and patients, new insights have emerged into the cellular and molecular etiology for the LV hypoplasia in HLHS. Cell proliferation defects were observed in conjunction with metaphase arrest and the disturbance of Hippo-YAP signaling. The left-sided restriction of the ventricular hypoplasia may result from epigenetic perturbation of pathways regulating left-right patterning. These findings suggest new avenues for fetal interventions with therapies using existing drugs that target the Hippo-YAP pathway and/or modulate epigenetic regulation.
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