Genome-wide association for heart failure: from discovery to clinical use

Crotonylation of NAE1 Modulates Cardiac Hypertrophy via Gelsolin Neddylation

BACKGROUND

Cardiac hypertrophy and its associated remodeling are among the leading causes of heart failure. Lysine crotonylation is a recently discovered posttranslational modification whose role in cardiac hypertrophy remains largely unknown. NAE1 (NEDD8 [neural precursor cell expressed developmentally downregulated protein 8]-activating enzyme E1 regulatory subunit) is mainly involved in the neddylation modification of protein targets. However, the function of crotonylated NAE1 has not been defined. This study aims to elucidate the effects and mechanisms of NAE1 crotonylation on cardiac hypertrophy.

METHODS

Crotonylation levels were detected in both human and mouse subjects with cardiac hypertrophy through immunoprecipitation and Western blot assays. Tandem mass tag (TMT)-labeled quantitative lysine crotonylome analysis was performed to identify the crotonylated proteins in a mouse cardiac hypertrophic model induced by transverse aortic constriction. We generated NAE1 knock-in mice carrying a crotonylation-defective K238R (lysine to arginine mutation at site 238) mutation (NAE1 K238R) and NAE1 knock-in mice expressing a crotonylation-mimicking K238Q (lysine to glutamine mutation at site 238) mutation (NAE1 K238Q) to assess the functional role of crotonylation of NAE1 at K238 in pathological cardiac hypertrophy. Furthermore, we combined coimmunoprecipitation, mass spectrometry, and dot blot analysis that was followed by multiple molecular biological methodologies to identify the target GSN (gelsolin) and corresponding molecular events contributing to the function of NAE1 K238 (lysine residue at site 238) crotonylation.

RESULTS

The crotonylation level of NAE1 was increased in mice and patients with cardiac hypertrophy. Quantitative crotonylomics analysis revealed that K238 was the main crotonylation site of NAE1. Loss of K238 crotonylation in NAE1 K238R knock-in mice attenuated cardiac hypertrophy and restored the heart function, while hypercrotonylation mimic in NAE1 K238Q knock-in mice significantly enhanced transverse aortic constriction-induced pathological hypertrophic response, leading to impaired cardiac structure and function. The recombinant adenoviral vector carrying NAE1 K238R mutant attenuated, while the K238Q mutant aggravated Ang II (angiotensin II)-induced hypertrophy. Mechanistically, we identified GSN as a direct target of NAE1. K238 crotonylation of NAE1 promoted GSN neddylation and, thus, enhanced its protein stability and expression. NAE1 crotonylation-dependent increase of GSN promoted actin-severing activity, which resulted in adverse cytoskeletal remodeling and progression of pathological hypertrophy.

CONCLUSIONS

Our findings provide new insights into the previously unrecognized role of crotonylation on nonhistone proteins during cardiac hypertrophy. We found that K238 crotonylation of NAE1 plays an essential role in mediating cardiac hypertrophy through GSN neddylation, which provides potential novel therapeutic targets for pathological hypertrophy and cardiac remodeling.

Mendelian randomization of plasma lipidome, inflammatory proteome and heart failure

AIMS

Heart failure (HF) is a global health issue, with lipid metabolism and inflammation critically implicated in its progression. This study harnesses cutting-edge, expanded genetic information for lipid and inflammatory protein profiles, employing Mendelian randomization (MR) to uncover genetic risk factors for HF.

METHODS

We assessed genetic susceptibility to HF across 179 lipidomes and 91 inflammatory proteins using instrumental variables (IVs) from recent genome-wide association studies (GWASs) and proteome-wide quantitative trait loci (pQTL) studies. GWASs involving 47 309 HF cases and 930 014 controls were obtained from the Heart Failure Molecular Epidemiology for Therapeutic Targets (HERMES) Consortium. Data on 179 lipids from 7174 individuals in a Finnish cohort and 91 inflammatory proteins from a European pQTL study involving 14 824 individuals are available in the HGRI-EBI catalogue. A two-sample MR approach evaluated the associations, and a two-step mediation analysis explored the mediation role of inflammatory proteins in the lipid-HF pathway. Sensitivity analyses, including MR-RAPS (robust adjusted profile score) and MR-Egger, ensured result robustness.

RESULTS

Genetic IVs for 162 lipids and 74 inflammatory proteins were successfully identified. MR analysis revealed a genetic association between HF and 31 lipids. Among them, 18 lipids, including sterol ester (27:1/18:0), cholesterol, 9 phosphatidylcholines, phosphatidylinositol (16:0_20:4) and 6 triacylglycerols, were identified as HF risk factors [odds ratio (OR) = 1.037-1.368]. Cholesterol exhibited the most significant association with elevated HF risk [OR = 1.368, 95% confidence interval (CI) = 1.044-1.794, P = 0.023]. In the inflammatory proteome, leukaemia inhibitory factor receptor (OR = 0.841, 95% CI = 0.789-0.897, P = 1.08E-07), fibroblast growth factor 19 (OR = 0.905, 95% CI = 0.830-0.988, P = 0.025) and urokinase-type plasminogen activator (OR = 0.938, 95% CI = 0.886-0.994, P = 0.030) were causally negatively correlated with HF, whereas interleukin-20 receptor subunit alpha (OR = 1.333, 95% CI = 1.094-1.625, P = 0.004) was causally positively correlated with HF. Mediation analysis revealed leukaemia inhibitory factor receptor (mediation proportion: 23.5%-25.2%) and urokinase-type plasminogen activator (mediation proportion: 9.5%-10.7%) as intermediaries in the lipid-inflammation-HF pathway. No evidence of directional horizontal pleiotropy was observed (P > 0.05).

CONCLUSIONS

This study identifies a genetic connection between certain lipids, particularly cholesterol, and HF, highlighting inflammatory proteins that influence HF risk and mediate this relationship, suggesting new therapeutic targets and insights into genetic drivers in HF.

NAT10 Is Involved in Cardiac Remodeling Through ac4C-Mediated Transcriptomic Regulation

BACKGROUND

Heart failure, characterized by cardiac remodeling, is associated with abnormal epigenetic processes and aberrant gene expression. Here, we aimed to elucidate the effects and mechanisms of NAT10 (N-acetyltransferase 10)-mediated N4-acetylcytidine (ac4C) acetylation during cardiac remodeling.

METHODS

NAT10 and ac4C expression were detected in both human and mouse subjects with cardiac remodeling through multiple assays. Subsequently, acetylated RNA immunoprecipitation and sequencing, thiol-linked alkylation for the metabolic sequencing of RNA (SLAM-seq), and ribosome sequencing (Ribo-seq) were employed to elucidate the role of ac4C-modified posttranscriptional regulation in cardiac remodeling. Additionally, functional experiments involving the overexpression or knockdown of NAT10 were conducted in mice models challenged with Ang II (angiotensin II) and transverse aortic constriction.

RESULTS

NAT10 expression and RNA ac4C levels were increased in in vitro and in vivo cardiac remodeling models, as well as in patients with cardiac hypertrophy. Silencing and inhibiting NAT10 attenuated Ang II-induced cardiomyocyte hypertrophy and cardiofibroblast activation. Next-generation sequencing revealed ac4C changes in both mice and humans with cardiac hypertrophy were associated with changes in global mRNA abundance, stability, and translation efficiency. Mechanistically, NAT10 could enhance the stability and translation efficiency of CD47 and ROCK2 transcripts by upregulating their mRNA ac4C modification, thereby resulting in an increase in their protein expression during cardiac remodeling. Furthermore, the administration of Remodelin, a NAT10 inhibitor, has been shown to prevent cardiac functional impairments in mice subjected to transverse aortic constriction by suppressing cardiac fibrosis, hypertrophy, and inflammatory responses, while also regulating the expression levels of CD47 and ROCK2 (Rho associated coiled-coil containing protein kinase 2).

CONCLUSIONS

Therefore, our data suggest that modulating epitranscriptomic processes, such as ac4C acetylation through NAT10, may be a promising therapeutic target against cardiac remodeling.