RNA polymerase loss by nuclear rupture drives LMNA cardiomyopathy

Localized rupture of the nuclear envelope has recently been reported in various pathologies, including cancer ^1,2 , neurodegenerative disease ^3–5 , myocardial infarction ⁶ , as well as dilated cardiomyopathy caused by Lamin A/C gene mutations (LMNA-DCM) ⁷ . Whether and how nuclear rupture contributes to disease remains unknown. Here, we report that nuclear rupture causes global transcriptional deficiency in a mouse model of LMNA-DCM. We observed that ruptured nuclei lost RNA polymerase II, leading to downregulation of numerous genes essential for cardiomyocyte structure and function. We identified endogenous resealing of nuclear rupture as a cardioprotective mechanism in LMNA-DCM mouse hearts. Resealing involved the ESCRT-III membrane remodeling complex recruited to nuclear rupture sites. Resealed nuclei restored transcription while inhibiting ESCRT-III activity accelerated cardiomyopathy. However, resealed nuclei were short-lived: they re-ruptured at twice the rate of resealing. A kinetic model predicted progressive accumulation of ruptured nuclei despite ongoing resealing. Consistently, a human LMNA-DCM heart contained numerous ruptured nuclei at disease presentation. These findings linked nuclear rupture to organ deterioration through global transcriptional deficiency and suggested rupture resealing as a critical modifier of nuclear rupture-associated conditions.