bims-mignad 2024-09-22 papers

Issue of 2024–09–22
three papers selected by
Melisa Emel Ermert, Amsterdam UMC

Nat Cardiovasc Res. 2024 Sep 18.

Cardiac NAD+ depletion in mice promotes hypertrophic cardiomyopathy and arrhythmias prior to impaired bioenergetics.

Nicotinamide adenine dinucleotide (NAD+) is an essential co-factor in metabolic reactions and co-substrate for signaling enzymes. Failing human hearts display decreased expression of the major NAD+ biosynthetic enzyme nicotinamide phosphoribosyltransferase (Nampt) and lower NAD+ levels, and supplementation with NAD+ precursors is protective in preclinical models. Here we show that Nampt loss in adult cardiomyocytes caused depletion of NAD+ along with marked metabolic derangements, hypertrophic remodeling and sudden cardiac deaths, despite unchanged ejection fraction, endurance and mitochondrial respiratory capacity. These effects were directly attributable to NAD+ loss as all were ameliorated by restoring cardiac NAD+ levels with the NAD+ precursor nicotinamide riboside (NR). Electrocardiograms revealed that loss of myocardial Nampt caused a shortening of QT intervals with spontaneous lethal arrhythmias causing sudden cardiac death. Thus, changes in NAD+ concentration can have a profound influence on cardiac physiology even at levels sufficient to maintain energetics.

DOI: https://doi.org/10.1038/s44161-024-00542-9

Exp Gerontol. 2024 Sep 18. pii: S0531-5565(24)00230-4. [Epub ahead of print]196 112584

Employ machine learning to identify NAD+ metabolism-related diagnostic markers for ischemic stroke and develop a diagnostic model.

Yameng Sun, Shenghao Ding, Fei Shen, Xiaolan Yang, Wenhua Sun, Jieqing Wan.

Ischemic stroke (IS) is a severe condition regulated by complex molecular alterations. This study aimed to identify potential nicotinamide adenine dinucleotide (NAD+) metabolism-associated diagnostic markers of IS and explore their associations with immune dynamics. Weighted Gene Co-expression Network Analysis and single-sample gene set enrichment analysis (ssGSEA) were employed to identify key gene modules on the GEO dataset (GSE16561). LASSO regression was used to identify diagnostic genes. A diagnostic model was then developed using the training dataset, and its performance was assessed using a validation dataset (GSE22255 dataset). Associations between hub genes and immune cells, immune response genes, and human leukocyte antigen (HLA) genes were assessed by ssGSEA. A regulatory network was constructed using mirBase and TRRUST databases. A total of 20 NAD+ metabolic genes exhibited noteworthy expression variations. Within the module notably associated with NAD+ metabolism, 19 specific genes were included in the diagnostic model, which was validated on the GSE22255 dataset (AUC: 0.733). There were significant disparities in immune cell populations, immune response genes, and HLA gene expression, all of which were associated with the hub genes. A regulatory network composed of 153 edges and 103 nodes was constructed. This study advances our understanding of IS by providing insights into NAD+ metabolism and gene interactions, contributing to potential diagnostic innovations in IS.

Keywords: Immune environment; Ischemic stroke; LASSO; Multi-factor regulatory network; NAD+ metabolism; WGCNA; ssGSEA

DOI: https://doi.org/10.1016/j.exger.2024.112584

Cell Signal. 2024 Sep 12. pii: S0898-6568(24)00377-2. [Epub ahead of print]124 111409

SIRT1-FOXOs signaling pathway: A potential target for attenuating cardiomyopathy.

Changxu Lu, Can Gao, Jinwen Wei, Dan Dong, Mingli Sun.

Cardiomyopathy constitutes a global health burden. It refers to myocardial injury that causes alterations in cardiac structure and function, ultimately leading to heart failure. Currently, there is no definitive treatment for cardiomyopathy. This is because existing treatments primarily focus on drug interventions to attenuate symptoms rather than addressing the underlying causes of the disease. Notably, the cardiomyocyte loss is one of the key risk factors for cardiomyopathy. This loss can occur through various mechanisms such as metabolic disturbances, cardiac stress (e.g., oxidative stress), apoptosis as well as cell death resulting from disorders in autophagic flux, etc. Sirtuins (SIRTs) are categorized as class III histone deacetylases, with their enzyme activity primarily reliant on the substrate nicotinamide adenine dinucleotide (NAD (+)). Among them, Sirtuin 1 (SIRT1) is the most intensively studied in the cardiovascular system. Forkhead O transcription factors (FOXOs) are the downstream effectors of SIRT1. Several reports have shown that SIRT1 can form a signaling pathway with FOXOs in myocardial tissue, and this pathway plays a key regulatory role in cell loss. Thus, this review describes the basic mechanism of SIRT1-FOXOs in inhibiting cardiomyocyte loss and its favorable role in cardiomyopathy. Additionally, we summarized the SIRT1-FOXOs related regulation factor and prospects the SIRT1-FOXOs potential clinical application, which provide reference for the development of cardiomyopathy treatment.

Keywords: Cardiomyocytes loss; Cardiomyopathy; Deacetylation; Myocardial injury; PTMs; SIRT1-FOXOs

DOI: https://doi.org/10.1016/j.cellsig.2024.111409