Modeling of lamin A/C mutation premature cardiac aging using patient­specific induced pluripotent stem cells.

AIMS: We identified an autosomal dominant non­sense mutation (R225X) in exon 4 of the lamin A/C (LMNA) gene in a Chinese family spanning 3 generations with familial dilated cardiomyopathy (DCM). In present study, we aim to generate induced pluripotent stem cells derived cardiomyocytes (iPSC­CMs) from an affected patient with R225X and another patient bearing LMNA frame­shift mutation for drug screening. METHODS AND RESULTS: Higher prevalence of nuclear bleb formation and micronucleation was present in LMNA(R225X/WT) and LMNA(Framshift/WT) iPSC­CMs. Under field electrical stimulation, percentage of LMNA­mutated iPSC­CMs exhibiting nuclear senescence and cellular apoptosis markedly increased. shRNA knockdown of LMNA replicated those phenotypes of the mutated LMNA field electrical stress. Pharmacological blockade of ERK1/2 pathway with MEK1/2 inhibitors, U0126 and selumetinib (AZD6244) significantly attenuated the pro­apoptotic effects of field electric stimulation on the mutated LMNA iPSC­CMs. CONCLUSION: LMNA­related DCM was modeled in­vitro using patient­specific iPSC­CMs. Our results demonstrated that haploinsufficiency due to R225X LMNA non­sense mutation was associated with accelerated nuclear senescence and apoptosis of iPSC­ CMs under electrical stimulation, which can be significantly attenuated by therapeutic blockade of stress­related ERK1/2 pathway.