Targeting age-related LINE-1 activation alleviates cardiac aging

Cardiac aging is a major driver of cardiovascular diseases and associated mortality, yet its therapeutic options are limited. While long interspersed nuclear element-1 (LINE-1) retrotransposons are known to drive cellular senescence, their role in cardiac aging is poorly defined. Here we showed that LINE-1 expression increased in the heart with age. To investigate their role in cardiac aging, we generated cardiomyocyte-specific Mov10-knockout mice, which failed to suppress LINE-1. These mice developed LINE-1 derepression, cardiac dysfunction and premature cardiac aging by 3 months of age, accompanied by cGAS-STING activation. Pharmacological inhibition of LINE-1 reverse transcription (with 3TC) or STING (with H-151) suppressed cGAS-STING activation and attenuated senescence in Mov10-knockout H9C2 cells. Notably, both inhibitors improved cardiac function and reduced cardiac inflammation and senescence phenotypes in naturally aged mice. Together, our findings establish LINE-1 as a driver of cardiac aging via cGAS-STING activation, highlighting LINE-1 and its downstream effectors as therapeutic targets for age-related cardiac dysfunction.