LMNA-Related Dilated Cardiomyopathy: Single-Cell Transcriptomics during Patient-Derived iPSC Differentiation Support Cell Type and Lineage-Specific Dysregulation of Gene Expression and Development for Cardiomyocytes and Epicardium-Derived Cells

LMNA-Related DCM involves cardiomyocyte dysfunction resulting in heart failure or sudden death. It is caused by LMNA mutations encoding Lamin A/C defects involved in nuclear integrity and gene expression. To investigate possible mechanisms, we used iPSC derived from a LMNA c.357-2A>G Patient and her unaffected sister. We differentiated iPSC and conducted scRNA-seq for 4 Patient and 8 Control samples across seven time points from Day 0 to 30. Using a comprehensive bioinformatics workflow, we identified 110,521 high-quality cells and complex heterogeneity: ten main cell types, possible subtypes, and lineage bifurcation for Cardiac Progenitors to Cardiomyocytes and Epicardium-Derived Cells (EPDC). By comparative analyses, we found differentially expressed genes (DEG) and enrichment supporting pathway dysregulation for ZNF genes and RNA polymerase II transcription in Pluripotent cells; BMP4 and TGF Beta/BMP signaling, sarcomere genes and cardiogenesis, CDH2 and EMT in Cardiomyocytes; LMNA and epigenetic regulation and DDIT4 and mTORC1 signaling in EPDC. In addition, top DEG included XIST, six imprinted genes, and gene sets in metabolism, proliferation, and homeostasis. We confirmed Lamin A/C haploinsufficiency by allelic expression and Western blot. Our evidence supports disruption of epigenomic developmental programs in LMNA-Related DCM and also demonstrates current challenges of LMNA disease modeling using Patient-derived iPSC.