LncRNA H19 Upregulation Links Hypoplastic Left Heart Syndrome to Impaired PINK1/Parkin-Mediated Mitophagy and Ischemic Vulnerability

BACKGROUND The myocardium in hypoplastic left heart syndrome (HLHS) exhibits immature metabolic programming, impaired mitochondrial quality control, and heightened susceptibility to ischemic and hypoxic injury during palliative surgery. The long non-coding RNA H19 suppresses translation of PTEN-induced putative kinase 1 (PINK1) mRNA and modulates mitochondrial quality control and ischemia/reperfusion injury (IRI) in adult hearts. Whether—and how—H19 regulates mitophagy and IRI in HLHS or in immature animals remains unknown.

We investigated H19 regulation and its role in mitophagy and ischemia/reperfusion or hypoxia/reoxygenation injury in myocardial tissue from HLHS patients, HLHS-specific induced pluripotent stem cell–derived cardiomyocytes (HLHS-iPSC-CMs), and immature rat hearts. Mechanistic interactions among H19, PINK1/Parkin signaling, and mitophagosome formation were assessed using loss-of-function approaches.

HLHS myocardium exhibited markedly elevated H19 expression, accompanied by reduced PINK1 and Parkin protein abundance and diminished mitophagosome formation. Similar findings were observed in HLHS-iPSC-CMs exposed to hypoxia/reoxygenation and in immature rat hearts subjected to myocardial IRI. H19 knockdown in HLHS-iPSC-CMs attenuated hypoxia/reoxygenation–induced lactate dehydrogenase release and restored PINK1 and Parkin protein levels. In immature rats, myocardial H19 silencing reduced infarct size, enhanced mitochondrial PINK1 and Parkin expression, and improved post-reperfusion cardiac function for up to 28 days. Conversely, knockdown of PINK1 or Parkin reduced mitophagosome formation and exacerbated functional deterioration during IRI.

H19 upregulation impairs PINK1/Parkin-dependent mitophagy and increases susceptibility to ischemic and hypoxic injury in HLHS and the immature heart. These findings identify H19 as a key regulator of mitochondrial quality control and a potential therapeutic target for mitigating IRI in early-life cardiac disease. What Is Known? The myocardium in hypoplastic left heart syndrome (HLHS) exhibits immature metabolic programming, abnormal coronary perfusion, and impaired mitochondrial quality control, rendering it highly susceptible to ischemic and hypoxic injury. Both structural limitations and intrinsic mitochondrial dysfunction contribute to the reduced ischemic tolerance of the HLHS heart, particularly during surgical and hemodynamic stress. The long noncoding RNA H19 regulates mitochondrial quality control and modulates myocardial ischemia/reperfusion injury (IRI) in adult hearts. H19 inhibits the binding of the translation initiation factor eIF4A2 to PTEN-induced putative kinase 1 (PINK1) mRNA, thereby suppressing PINK1 protein synthesis and influencing PINK1-dependent mitophagy in adult mice. What New Information Does This Article Contribute? This study identifies robust upregulation of H19 in HLHS myocardium, HLHS-specific induced pluripotent stem cell–derived cardiomyocytes (HLHS-iPSC-CMs) exposed to hypoxia/reoxygenation, and in immature rats subjected to myocardial IRI. Elevated H19 is associated with suppressed PINK1/Parkin-dependent mitophagy, exacerbated IRI, and adverse post-injury remodeling. Knockdown of H19 restores mitochondrial PINK1 and Parkin protein levels, enhances mitophagy, reduces infarct size, and improves long-term recovery of cardiac function—demonstrating a previously unrecognized pathogenic role for H19 in the immature heart under stress. Knockdown of PINK1 or Parkin decreases mitophagosomes and exacerbates myocardial IRI in immature rats. Competing Interest Statement The authors have declared no competing interest.