Generation of an isogenic human induced pluripotent stem cell line with a mutant propionyl-CoA carboxylase α subunit.

BACKGROUND

Propionic acidemia (PA) is a rare autosomal recessive metabolic disorder caused by defects in propionyl-CoA carboxylase (PCC), a mitochondrial enzyme composed of six alpha (PCCA) and six beta (PCCB) subunits. Mutations in PCCA/PCCB genes disrupt PCC function, leading to toxic metabolite accumulation and clinical manifestations. Current research is limited by inadequate patient-derived cellular models and ethical constraints in sample acquisition.

METHOD: Using CRISPR/Cas9-mediated gene editing, we established an isogenic human induced pluripotent stem cell (iPSC) line carrying the PCCA c.2002G> A mutation. The mutant iPSCs were further subjected to directed cardiac differentiation. Characteristic metabolites in the iPSC-derived cardiomyocytes (iPSC-CMs) culture medium were analyzed via untargeted metabolomics, and contractile function was assessed by video-based motion analysis under propionate challenge.

RESULTS

The mutant iPSCs showed sustained expression of pluripotency markers (OCT4, NANOG, SOX-2), maintained normal karyotype (46, XY), and retained trilineage differentiation capacity. Functional characterization demonstrated significantly reduced PCC enzyme activity, accurately modeling PA metabolic pathology. Furthermore, the mutant iPSCs successfully differentiated into cardiomyocytes and exhibited a PA-specific metabolic profile, including significantly elevated propionylcarnitine levels. Upon propionate treatment (2.5 mM), the contractile function of mutant iPSC-CMs was significantly impaired, whereas wild-type iPSC-CMs showed the opposite response with enhanced contraction.

CONCLUSIONS

This isogenic iPSC line provides an ethically unconstrained platform to investigate PA molecular mechanisms and genotype-phenotype relationships. The model enables systematic drug screening and therapeutic development while overcoming patient sample limitations.