Journal: bioRxiv
Article Title: Abnormal ventricular wall patterning precedes and drives MYBPC3 hypertrophic cardiomyopathy
doi: 10.64898/2026.03.25.714341
Figure Lengend Snippet: ( A ) Whole-mount views of P7 control, Mybpc3 +/+ ;R26 Prdm16/+ ;Myh6 MerCreMer/+ , homozygous Mybpc3 p.Pro109Serfs*12 and Mybpc3 p.Pro109Serfs*12;R26 Prdm16/+ ;Myh6 MerCreMer/+ hearts. Right, Cre-mediated transgenic expression was induced upon Tamoxifen administration at P1. Scale bar, 250 μm. ( B ) Quantification of Heart weight/Body weight ratio (n=25 Mybpc3+/+, n=16 Mybpc3+/+;R26 Prdm16/+ ;Myh6 MerCreMer/+ , n=13 homozygous Mybpc3 p.Pro109Serfs*12 and n=14 Mybpc3 p.Pro109Serfs*12;R26 Prdm16/+ ;Myh6 MerCreMer/+ ), Septum thickness (μm), Left Ventricular Free Wall (LVFW) thickness (μm)(n=4 Mybpc3+/+, n=3 Mybpc3+/+;R26 Prdm16/+ ;Myh6 MerCreMer/+ , n=3 homozygous Mybpc3 p.Pro109Serfs*12 and n=5 Mybpc3 p.Pro109Serfs*12;R26 Prdm16/+ ;Myh6 MerCreMer ≥3 sections per heart), compact myocardium leght (CM) and trabecular myocardium leght (TM) (μm) (n=3 hearts per genotype, ≥3 sections per heart). Data are represented as means ± SD. Statistical significance was determined by unpaired Student’s t-test (ns, not significant; * p -value < 0.05; *** p -value < 0.001; **** p -value < 0.0001). ( C ) H&E images of representative hearts of the different genotypes. Scale bar, 250 μm. ( D ) ISH for Nppa in the different genotypes. Scale bar, 250 μm. ( E ) WGA (green) and DAPI (blue) fluorescence staining of P7 control, Mybpc3 +/+ ;R26 Prdm16/+ ;Myh6 MerCreMer/+ , Mybpc3 p.Pro109Serfs*12 and Mybpc3 p.Pro109Serfs*12;R26 Prdm16/+ ;Myh6 MerCreMer/+ heart sections. Scale bar, 10 μm. ( F ) Cardiomyocyte cross sectional area quantification of P7 hearts (n=3, ≥6 sections per heart). Data are represented as means ± SD. Statistical significance was determined by unpaired Student’s t-test (ns, not significant; * p -value < 0.05; ** p -value < 0.005). ( G ) Ventricular wall mispatterning drives MYBPC3-associated HCM that is attenuated by Prdm16 expression. Top, wild type: During late gestation (E18.5), compact (CM, Hey2⁺) and trabecular cardiomyocytes (TM, Hey2 - ) are spatially segregated and exhibit balanced proliferation, enabling ventricular compaction progression at birth (P1) and subsequent maturation. Postnatally, Prdm16 promotes cardiomyocyte maturation and restrains hypertrophy, resulting in normal ventricular architecture by P7. Middle, Mybpc3 P109Sfs*12 mutant. Mybpc3 loss disrupts ventricular wall patterning, leading to loss of compact–trabecular segregation, increased trabecular proliferation, and impaired compaction. This is accompanied by peak transcriptional dysregulation from P1 to P7. Abnormally reduced Prdm16 expression impairs maturation and contributes to pathological cardiomyocyte hypertrophy. Bottom, Mybpc3 P109Sfs*12; R26 Prdm16/+ ; Myh6 MerCreMer model. Tamoxifen-mediated Prdm16 expression at P1 attenuates hypertrophy despite persistent early patterning defects, promoting cardiomyocyte maturation and partially normalizing ventricular structure.
Article Snippet: A full-length mouse Prdm16 cDNA cloned into pcDNA3.1 was obtained from addgene (#15503).
Techniques: Control, Transgenic Assay, Expressing, Fluorescence, Staining, Mutagenesis