# Leucine‐Rich Repeat‐Containing G Protein‐Coupled Receptor 6 Ameliorates Pressure Overload‐Induced Cardiac Hypertrophy by Regulating Cardiomyocyte Metabolic Reprogramming

## TL;DR

This study shows that Lgr6 helps reduce heart enlargement caused by pressure overload by regulating heart cell metabolism.

## Contribution

The study reveals a novel mechanism by which Lgr6 regulates cardiac hypertrophy through the USP4-PPARα pathway.

## Key findings

- Lgr6 deficiency worsens, while overexpression reduces, pressure-induced heart enlargement.
- Lgr6 activates the cGMP/PKG/CREB1 pathway to regulate USP4 and PPARα expression.
- Targeting Lgr6 may offer a new therapeutic approach for pathological cardiac hypertrophy.

## Abstract

Metabolic reprogramming is a pivotal mechanism in the pathogenesis of pathological cardiac hypertrophy. Leucine‐rich repeat‐containing G protein‐coupled receptor 6 (Lgr6) has emerged as a significant player in cardiovascular diseases. In this study, the potential of Lgr6 to counteract pressure overload (PO)‐induced cardiac hypertrophy is investigated, and the underlying mechanisms involved are elucidated. Transverse aortic constriction (TAC) is induced to establish an in vivo cardiac hypertrophy model. Adeno‐associated virus 9 and adenovirus vectors are utilized to knock down and overexpress Lgr6 in cardiomyocytes, respectively. The effects of Lgr6 and its downstream molecules are subsequently determined using RNA sequencing and chromatin immunoprecipitation. Significant downregulation of Lgr6 expression is observed in the heart after TAC and in cardiomyocytes treated with phenylephrine. Lgr6 deficiency accelerated and Lgr6 overexpression inhibits cardiac hypertrophy and dysfunction after TAC. Mechanistically, the in vivo and in vitro experiments suggest that Lgr6 regulates the expression of ubiquitin specific protease 4 (USP4) and peroxisome proliferator‐activated receptor alpha (PPARα) by activating the cGMP/PKG/CREB1 signalling pathway, thereby regulating cardiomyocyte metabolic reprogramming after PO. Targeting Lgr6 can be a potential therapeutic strategy to treat pathological cardiac hypertrophy.

LGR6 overexpression ameliorates cardiac hypertrophy by regulating metabolic reprogramming through USP4‐PPARα pathway.