Cytoglobin-dependent NO-sGC-cGMP signaling regulates ventricular morphogenesis and diastolic function

Area of Science:

• Developmental Biology
• Cardiovascular Research
• Molecular Signaling

Background:

• Hypoplastic left heart syndrome (HLHS) is a severe congenital heart defect.
• Nitric oxide (NO) signaling is clinically used in HLHS, but its role in pathogenesis is unclear.
• Cytoglobin (Cygb) traditionally limits NO, but recent work shows it enhances NO-sGC-cGMP signaling.

Purpose of the Study:

• Investigate if Cygb-dependent NO-sGC signaling, linked to cilia function, regulates cardiac morphogenesis.
• Determine if this pathway contributes to ventricular hypoplasia in HLHS.

Main Methods:

• Utilized zebrafish ( cygb2 mutants) to study cardiogenesis.
• Examined effects of genetic disruption of sGC ⍺-subunit ( gucy1a1).
• Employed pharmacological NO scavenging and cGMP level assessment.

Main Results:

• Loss of Cygb disrupted NO-sGC signaling, altering cardiac progenitor organization and migration.
• Impaired heart tube morphogenesis led to compact ventricular walls, reduced size, and decreased stroke volume, mimicking HLHS.
• Genetic and pharmacological disruption of NO-sGC signaling phenocopied the cygb2 mutant phenotype.

Conclusions:

• Cygb-dependent NO-sGC signaling is critical for ventricular development and performance.
• This pathway links cardiac progenitor dynamics to cilia-dependent left-right patterning.
• Pharmacological sGC activation may offer a therapeutic strategy for hypoplastic ventricular disease.