Circulation research最新文献

Background: The adult mammalian heart lacks the significant regenerative potential needed to cope with the massive loss of cardiomyocytes following myocardial infarction. Ultimately, irreversible cardiac damage leads to heart failure, which is associated with a poor prognosis. Given this, reactivating dormant regenerative processes in the injured heart represents an attractive therapeutic approach. When regeneration does occur, newly formed cardiomyocytes are derived from preexisting ones.

Methods: We aimed to identify novel regulators of cardiomyocyte proliferation. In this context, the genome is transcribed for a large part into RNAs with little or no protein-coding potential. Among noncoding RNAs, long noncoding RNAs represent the most diverse class of molecules and are implicated in numerous epigenetic mechanisms, making them ideal targets for controlling cell identity and behavior. In this project, we developed a high-throughput screening assay to identify long noncoding RNAs that promote cardiomyocyte proliferation upon knockdown. Using a stringent selection pipeline, we identified Clipper, an enhancer-associated long noncoding RNA regulating the expression of its cognate protein-coding gene Lpin1 in cis.

Results: Clipper was found to control mitochondrial biogenesis via LPIN1 (Lipin1). Specifically, productive mitochondrial division, characterized by fission site positioning at the midzone of the mitochondrion, was stimulated by Clipper or Lpin1 silencing. The process was associated with a change in mitochondrial bioenergetics, particularly decreased oxidative metabolism, reduced production of reactive oxygen species, and dampened DNA damage, creating favorable conditions for cardiomyocyte proliferation. Clipper knockdown in vivo following myocardial infarction stimulated cardiac regeneration in the damaged myocardium, leading to the restoration of heart function. Importantly, CLIPPER is positionally and functionally conserved in humans.

Conclusions: Our data identify CLIPPER as a promising therapeutic target for heart regeneration, acting through control of LPIN1-dependent mitochondrial biogenesis and cardiomyocyte proliferation.

Background: Cardiovascular disease remains the leading cause of death worldwide, with coronary artery disease being the primary contributor. Our recent studies suggest that activation of LepRs (leptin receptors) in the brain can improve cardiac function after myocardial infarction. However, the mechanism by which this cardioprotective effect is transmitted from the brain to the heart remains unclear. We hypothesize that brain LepR activation stimulates brown adipose tissue (BAT) to secrete extracellular vesicles (EVs) enriched with cardioprotective factors. These EVs may safeguard the heart by modulating cardiac mitochondrial function and collagen deposition.

Methods: Sprague-Dawley rats with BAT intact, BAT ablation, or BAT sympathetic denervation were implanted with an intracerebroventricular cannula for continuous leptin or vehicle delivery over 28 days after cardiac ischemia-reperfusion injury. Cardiac function was assessed weekly via echocardiography and by ventricular catheterization at the end of the protocol. EVs were isolated from BAT for analysis. Rab27a (Ras-related protein Rab-27A), a protein required for EV release, was knocked down using adeno-associated virus, and EV tracking was conducted using a double fluorescent reporter mouse model.

Results: Our findings indicate that BAT ablation or BAT sympathetic denervation diminishes the cardioprotective effects of brain LepR activation. We also observed an increased concentration of EVs within the BAT of rats treated with intracerebroventricular leptin compared with vehicle-treated controls, an effect abolished by BAT denervation. Furthermore, knockdown of Rab27a in BAT reduced the cardioprotective benefits of brain LepR activation. MicroRNA miR-29c-3p was identified as a cargo of leptin-stimulated BAT-derived EVs and appears to play a key role in mitigating cardiac fibrosis after ischemia-reperfusion injury in leptin-treated animals.

Conclusions: Activation of LepR in the brain protects the heart after ischemia-reperfusion injury via sympathetic-mediated BAT-derived EVs enriched with miR-29c-3p.

Background: Pathogenic cardiac hypertrophy, often driven by mechanical stress, is a leading cause of heart failure. However, effective therapeutic targets remain limited. TMC6 (transmembrane channel-like protein 6) is abundant in healthy myocardium but downregulated in hypertrophic hearts; its role in cardiac hypertrophy remains undefined.

Methods: We combined cardiac-specific Tmc6 knockout mice subjected to transverse aortic constriction surgery, neonatal rat ventricular myocytes, and CRISPR/Cas9-edited human pluripotent stem cell-derived cardiomyocytes to assess hypertrophy and signaling readouts. Subcellular localization, protein-protein interaction, and competitive peptide assays were used to dissect the mechanism. Adeno-associated virus serotype 9 (AAV9)-cTnT (cardiac troponin T)-TMC6 was used for in vivo rescue.

Results: TMC6 deficiency increased cardiomyocyte size, fetal gene expression, and adverse remodeling in vivo and in vitro, whereas TMC6 overexpression blunted hypertrophic responses. Full-length TMC6 localized to the endoplasmic reticulum and bound CIB1 (calcium and integrin-binding protein 1) to sequester it in the endoplasmic reticulum, limiting CIB1 access to sarcolemmal Ca²⁺ microdomains required to scaffold calcineurin and activate NFAT (nuclear factor of activated T cells). A cell-permeable TMC6^161-180 peptide competitively displaced CIB1 from TMC6 and augmented hypertrophy in wild-type but not Tmc6 knockout cardiomyocytes, indicating a dominant-negative mechanism. Therapeutically, AAV9-cTnT-TMC6 restored TMC6-CIB1 engagement, suppressed calcineurin/NFAT readouts, and improved function after pressure overload.

Conclusions: TMC6 is an endogenous brake on pathological hypertrophy that restrains CIB1-calcineurin/NFAT signaling via endoplasmic reticulum sequestration of CIB1. Restoring full-length TMC6 mitigates pressure-overload remodeling, nominating the TMC6-CIB1 axis as a therapeutic target.

Background: Atherosclerosis occurs preferentially in regions of disturbed fluid shear stress (FSS), whereas physiological laminar FSS protects against disease by suppressing endothelial inflammation. Proinflammatory versus anti-inflammatory programs are associated with glycolysis versus oxidative phosphorylation, respectively, but mechanisms are poorly understood. The TF (transcription factor) FOXO1 (forkhead box protein O1) is known to regulate endothelial metabolism and angiogenesis, but little is known about its role in endothelial inflammation.

Methods: Endothelial cells were treated with cytokines or subjected to defined flow patterns in vitro using a parallel plate flow chamber. Immunofluorescence, RNA sequencing, and biochemical assays assessed FOXO1 localization, gene expression, and posttranslational modifications. In vivo experiments used FOXO1-floxed mice crossed with Bmx-CreER^T2 for artery endothelial cell-specific FOXO1 knockout. Hyperlipidemia was induced via injection of PCSK9 (proprotein convertase subtilisin/kexin type 9) adeno-associated virus and high-cholesterol/high-fat diet to assess atherosclerosis.

Results: Oscillatory FSS and inflammatory cytokines induced whereas physiological FSS inhibited FOXO1 nuclear translocation. Depleting FOXO1 in endothelial cells upregulated the protective flow-responsive TFs KLF (Krüppel-like factor) 2/4 and reduced oscillatory FSS-induced inflammatory genes. Inhibition of FOXO1 nuclear translocation by physiological FSS is mediated via a KLF2-CDK2 (cell cycle-dependent kinase 2) pathway, with the latter phosphorylating FOXO1 at S249. Artery endothelial cell-specific deletion of FOXO1 significantly reduced atherosclerotic plaques in hyperlipidemic mice. Inhibition of glycolysis blocked oscillatory shear stress-induced FOXO1 nucleus translocation, while treatment with lactate promoted FOXO1 nuclear localization. These effects required lactyltransferase AARS1 (alanyl-tRNA synthetase 1) and correlated with FOXO1 lactylation.

Conclusions: These findings identify FOXO1 as a key mediator linking atheroprone flow and endothelial inflammatory gene expression via lactate-driven lactylation and nuclear translocation, promoting atherosclerosis. Conversely, physiological FSS suppresses FOXO1 via KLF2-CDK2 signaling. These complementary pathways suggest potential new therapeutic targets for treating atherosclerotic cardiovascular disease.

Background: Pathological cardiac hypertrophy is a major risk factor for heart failure. PGK1 (phosphoglycerate kinase 1) plays an important role in cellular energy metabolism. However, the functions of PGK1 in cardiac hypertrophy remain largely unexplored.

Methods: The expression and activity of PGK1, as well as its metabolite 3-phosphoglycerate, were examined in cardiac hypertrophy patients and mice subjected to transverse aortic constriction or Ang II (angiotensin II). Liquid chromatography-tandem mass spectrometry and co-immunoprecipitation analyses were used to identify the interacting proteins of PGK1. The potential effect of a PGK1 inhibitor CBR-470-1 was examined in a murine model of cardiac hypertrophy.

Results: The activation and upregulation of PGK1 were observed in myocardium tissues from mice and patients with cardiac hypertrophy. Cardiomyocyte-specific PGK1-deficiency alleviated cardiac hypertrophy and dysfunction in mice. Conversely, cardiomyocyte-specific PGK1 overexpression or infusion of 3-phosphoglycerate exacerbated cardiac hypertrophy. Mechanistically, PGK1 functioned as a protein kinase to stimulate phosphorylation of vimentin (Ser83), followed by FAK/Src-mediated phosphorylation of PI3K/Akt. The activated vimentin/PI3K/Akt signaling facilitated cardiomyocyte ferroptosis. Inhibition of PGK1 by CBR-470-1 prevented cardiac hypertrophy in cellular and animal models.

Conclusions: Our findings highlight a critical role for PGK1 in myocardial hypertrophy, with downstream activation of the vimentin/PI3K/Akt/ferroptosis pathway.

Background: The prevalence of heart failure is increasing globally, with poor prognosis, highlighting the need for novel therapeutic strategies. PKCα (protein kinase C alpha), encoded by PRKCA, plays a central role in heart failure pathogenesis. Phosphorylation of PKCα at threonine 497 (T497) triggers a series of intramolecular phosphorylation events, leading to its activation. Ablation of T497 phosphorylation leads to reduced stability and activity of PKCα.

Methods: We generated mice harboring a phospho-resistant PKCα (T497A) mutation in the germline using CRISPR-Cas9 (clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeat-associated 9)-mediated homology-directed repair. To assess the clinical feasibility of postnatal genome editing, we used CRISPR-Cas9 adenine base editing delivered by adeno-associated virus 9 to introduce the T497A substitution into the Prkca gene (Prkca^T497A) in wild-type mice. Mice underwent transverse aortic constriction to model heart failure. Cardiac function, hypertrophy, fibrosis, and transcriptional changes were evaluated by echocardiography, wheat germ agglutinin staining, Masson's trichrome staining, and RNA-sequencing. The editing efficiency of Prkca^T497A was assessed using Sanger sequencing and deep amplicon sequencing. To further explore its clinical potential, we introduced the PRKCA^T497A mutation into human induced pluripotent stem cells by nucleofection-mediated adenine base editing. Ca²⁺ homeostasis was analyzed in Fura-2-loaded human induced pluripotent stem cell-derived cardiomyocytes with PRKCA^T497A under chronic AngII (angiotensin II) stimulation.

Results: The T497A mutation in PKCα prevented its subsequent phosphorylation and led to PKCα protein degradation. Four weeks after transverse aortic constriction surgery, wild-type mice showed impaired cardiac function, cardiac remodeling, and increased lung weight. In contrast, PKCα phospho-resistant mice showed protection against heart failure-related aberrant changes in cardiac hypertrophy, fibrosis, and cardiac gene expression. Mice administered with adeno-associated virus 9 base editors to prevent T497 phosphorylation exhibited similar cardioprotective effects. In vitro, PKCα-edited induced pluripotent stem cell-derived cardiomyocyte were protected from AngII-induced impairments in contractility and Ca²⁺ transients.

Conclusions: The editing of PRKCA^T497A through adenine base editing represents a potential therapeutic approach for human cardiac diseases.

Cardiovascular diseases remain the leading global cause of morbidity and mortality, placing an escalating burden on health care systems and economies. While the gut microbiota is well recognized in atherosclerosis and cardiometabolic disorders, its influence on myocardial injury, repair, and regeneration is only beginning to emerge. Growing evidence reveals that gut microbes and their metabolites regulate myocardial health through intricate cross-organ networks, including the gut-brain-heart, gut-liver-heart, and gut-lung-heart axes. These findings suggest that the heart plays a key role in systemic host-microbe communication. Advances in metagenomics, metabolomics, and single-cell transcriptomics are now defining the molecular and cellular pathways by which microbial metabolites modulate immune tone, endothelial integrity, metabolic resilience, and cardiomyocyte survival. Studies in gnotobiotic models have established causal links between specific microbial taxa and myocardial outcomes while illuminating their roles in fibrosis resolution, angiogenesis, and regeneration. In this review, we synthesize current knowledge on the bidirectional gut-heart dialogue, emphasizing immunometabolic signaling, cross-organ integration, and regenerative mechanisms. We propose that coupling high-resolution multiomics with mechanistic modeling in controlled microbial systems will be pivotal for next-generation, microbiota-informed diagnostics, and therapeutics. We explore the emerging role of the gut-myocardium axis as both a driver of disease and as a promising modifiable therapeutic target and highlight a new frontier in precision cardiovascular medicine, with the potential to transform strategies for prevention, repair, and tissue regeneration.