Advanced iPSC-based modelling of LMNA-related congenital muscular dystrophy enables development of genetic therapies for muscle laminopathies.

Abstract

LMNArelated congenital muscular dystrophy (L-CMD) is one of the most severe laminopathies, which are incurable diseases primarily caused by pathogenic LMNA variants. LMNA encodes Lamin A/C: key components of the nuclear lamina, which provides structural stability to the nucleus, whilst regulating chromatin organisation and gene expression. L-CMD research is hindered by lack of humanised, tissue-specific models that accurately recapitulate disease phenotypes. We previously reported nuclear shape abnormalities and Lamin mislocalisation in LMNA-mutant induced pluripotent stem cell (iPSC)-derived skeletal muscle cells. Here, we expand the selection of L-CMD iPSCs, validate disease-associated readouts using a transgene-free differentiation protocol and assess gene editing strategies using 2D and 3D cultures. Results showed no overt defects in developmental myogenesis but recapitulated pathological nuclear shape abnormalities in monolayer cultures and engineered muscles, nuclear envelope protein mislocalisation and transcriptomic alterations across multiple pathogenic LMNA variants. We then used our platform to assess outcomes of LMNA gene editing. CRISPR-based exon-removal generated sRNA and protein Lamin A/C species, without normalisation of nuclear morphology or transcriptomic profile. Conversely, precise editing of the same variant corrected nuclear morphometrics, alongside normalisation of the pro-inflammatory transcriptomic signature, providing an advanced, humanised platform for translational research and precision medicine in laminopathies.