The long non-coding RNA CARDINAL attenuates cardiac hypertrophy by modulating protein translation

One of the features of pathological cardiac hypertrophy is enhanced translation and protein synthesis. Translational inhibition has been shown to be an effective means of treating cardiac hypertrophy, although system-wide side effects are common. Regulators of translation, such as cardiac-specific long non-coding RNAs (lncRNAs), could provide new, more targeted, therapeutic approaches to inhibit cardiac hypertrophy. Therefore, we generated mice lacking a previously identified lncRNA named CARDINAL to examine its cardiac function. We demonstrate that CARDINAL is a cardiac-specific, ribosome associated lncRNA and show that its expression is induced in the heart upon pathological cardiac hypertrophy; its deletion in mice exacerbates stress-induced cardiac hypertrophy and augments protein translation. In contrast, overexpression of CARDINAL attenuates cardiac hypertrophy in vivo and in vitro, and suppresses hypertrophy-induced protein translation. Mechanistically, CARDINAL interacts with developmentally regulated GTP binding protein 1 (DRG1) and blocks its interaction with DRG family regulatory protein 1 (DFRP1); as a result, DRG1 is downregulated, thereby modulating the rate of protein translation in the heart in response to stress. This study provides evidence for the therapeutic potential of targeting cardiac-specific lncRNAs to suppress disease-induced translational changes and to treat cardiac hypertrophy and heart failure.