NLRC5 enhances autophagy via inactivation of AKT/mTOR pathway and ameliorates cardiac hypertrophy

The aim of this study was to investigate the effect of nucleotide-binding oligomerization domain (NOD)-like receptor family CARD domain containing 5 (NLRC5) in cardiac hypertrophy, and to explore the mechanism implicated in this effect Cardiac hypertrophy was induced in neonatal rat cardiac myocytes using 1 μM of angiotensin II (Ang II) for 12, 24 and 48 h. Overexpression of NLRC5 was induced in H9C2 cells, and the NLRC5 + Ang II–treated cells were exposed to SC9 and 3‑methyladenine (3MA). An immunofluorescence assay was used for α-actinin staining, and quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) was performed for NLRC5, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) determination. Western blot analysis was applied to measure the levels of NLRC5, microtubule-associated protein 1A/1B-light chain 3 type I (LC3I), LC3II, sequestosome 1 (p62), protein kinase B (AKT), phosphorylated Akt (pAKT), mammalian target of rapamycin (mTOR) and phosphorylated mTOR (pmTOR). The level of NLRC5 was significantly decreased after Ang II treatment in cardiomyocytes, but the levels of ANP and BNP were increased. Overexpression of NLRC5 reduced the cell size, downregulated the levels of ANP and BNP, increased LC3II / LC3I, but decreased p62 in Ang II–induced cardiomyocyte hypertrophy. In addition, the results from Western blot showed that overexpression of NLRC5 distinctly decreased the ratios of pAKT/AKT and pmTOR/mTOR in cardiomyocyte hypertrophy. SC79 and 3MA significantly downregulated the ratio of LC3I/LC3II but increased the level of p62 in NLRC5 + Ang II–treated cells. These results provide a possible novel therapeutic strategy for cardiac hypertrophy that might be useful in a clinical setting.