Biology subjects

Warren, H. R.

Publications and source records attributed to Warren, H. R..

6 recordsLinked to original sources

bioRxiv2026

Fatty acid synthase coordinates mTOR signaling and histone crotonylation during cardiomyocyte hypertrophy

Background: Epigenetic modifications are central to the regulation of cardiac gene expression during disease. Among these, histone crotonylation (Kcr) has recently emerged as a key modulator of chromatin structure and transcriptional activity. Here, we identify a novel signaling axis linking fatty acid synthase (FASN) to mTOR activation and hypertrophic gene expression through histone crotonylation. Methods: FASN expression, mTOR activation, and histone crotonylation were assessed in mouse hearts and isolated cardiomyocytes using immunoblotting. FASN was silenced by siRNA or inhibited pharmacologically using TVB-2640. Hypertrophic gene expression was quantified by RT-qPCR. Cardiomyocyte hypertrophy was evaluated by immunofluorescence-based cell size analysis. p300 acetylation and crotonylation were assessed by immunoprecipitation and immunoblotting. CUT&RUN-seq and RNA-seq were performed to identify FASN- and Histone H3K18cr-regulated genes during hypertrophic stimulation. Bioinformatic analyses of human RNA-seq and genome-wide association study (GWAS) data were conducted to investigate the clinical relevance of these findings. Results: Histone crotonylation was markedly elevated in hypertrophic myocardium and cardiomyocytes. This increase was driven by upregulated FASN expression in response to hypertrophic stimuli. Genetic or pharmacological inhibition of FASN suppressed histone crotonylation, hypertrophic gene expression, and cardiomyocyte enlargement. Mechanistic studies suggested that FASN regulates histone crotonylation through mTOR-associated signaling and changes in p300 activity. Transcriptomic analyses further revealed that FASN enhances the expression of hypertrophy-associated genes enriched for histone crotonylation marks. Analysis of human sequencing datasets demonstrated a positive association between FASN expression and molecular markers of hypertrophy in patients with hypertrophic cardiomyopathy (HCM). Furthermore, GWAS analysis identified a variant at the FASN locus associated with heart failure as the underlying cause of death and increased FASN expression in cardiomyocytes. Conclusions: Our findings identify FASN as an important regulator of mTOR signalling and histone crotonylation during cardiomyocyte hypertrophy. These results support a potential mechanism linking altered lipid metabolism to epigenetic regulation and pathological cardiac remodelling.

cell biology↗

bioRxiv2025

Dietary glutamine supplementation alleviates age-related cardiac dysfunction by reducing elevated H3K27me3

BackgroundChanges to the epigenetic landscape play an important role in cardiovascular aging, where alterations in histone modifications influence gene expression by regulating DNA accessibility and chromatin structure. Our investigation into epigenetic changes during myocardial aging revealed that the repressive epigenetic mark H3K27me3 is significantly upregulated in aged mice and humans. This increase in H3K27me3 was shown to impair cardiomyocyte autophagy and drive metabolic reprogramming, key features of myocardial aging and causatively linked to dysfunction. Notably, by alleviating this repressive mark through a modified diet, we successfully mitigated the aged myocardial phenotype. MethodsHeart tissue from young and aged mice and humans was analyzed for H3K27me3 levels using immunoblotting and immunofluorescence staining. Genes regulated by H3K27me3 were identified through CUT&RUN-Seq and RNA-Seq, while metabolites were profiled using metabolomics. In neonatal rat ventricular myocytes (NRVMs), H3K27me3 levels were elevated by siRNA-mediated knockdown of UTX. Cellular metabolism was investigated using a Seahorse analyzer in cardiomyocytes with basal or elevated H3K27me3 levels. In further human studies, we assessed how circulating glutamine levels associate with the incidence of heart failure and the association of genetic variants within the SLC1A5 region with heart disease. In aged mice, H3K27me3 levels were reduced through a modified diet, and heart function was evaluated using echocardiography. Subsequently, hearts were processed for biochemical analysis, and autophagy was assessed using electron microscopy. ResultsH3K27me3 was significantly elevated in the aged mouse and human myocardium. This observed elevation in H3K27me3 was found to be attributed to impaired glutamine metabolism, resulting from reduced expression of the glutamine transporter SLC1A5 in the aged myocardium. Furthermore, elevation in H3K27me3 was found to contribute to impaired cardiomyocyte autophagy and metabolic dysfunction. In aged mice supplemented with a high glutamine diet this attenuated myocardial H3K27me3 and improved cardiac function. Furthermore, a high-glutamine diet reversed H3K27me3-mediated impairment in cardiac autophagy in aged mice. ConclusionsReduction in SLC1A5 during aging is likely to lead to increased myocardial H3K27me3 that results in impaired autophagy and metabolic reprogramming that contribute to the aged cardiac phenotype. Our findings also suggest glutamine may improve cardiac health in the aged population by lowering H3K27me3. Clinical PerspectiveO_ST_ABSWhat is new?C_ST_ABSO_LIElevation in H3K27me3 during aging is likely to lead to impaired myocardial autophagy and metabolic reprogramming. C_LIO_LIReduction in SLC1A5 during aging in humans is likely to contribute to myocardial dysfunction C_LIO_LIDietary supplementation of glutamine improves cardiac function in aged mice. C_LI What are the clinical implications?O_LITargeting H3K27me3 in the aged population may to mitigate cardiovascular disease C_LIO_LIDietary glutamine supplementation offers a promising strategy to improve cardiac function during aging. C_LI

cell biology↗

bioRxiv2022

An evolutionarily conserved olfactory receptor is required for sex differences in blood pressure

Sex differences in blood pressure are well-established, with premenopausal women having lower blood pressure than men by [~]10mmHg; however, the underlying mechanisms are not fully understood. We report here that olfactory receptor 558 (Olfr558), which has not previously been studied in non-olfactory tissues, localizes to vascular smooth muscle cells in numerous tissues including the kidney and heart. In the kidney, Olfr558 colocalizes with renin (a hormone that plays a key role in blood pressure regulation) in the renal afferent arteriole. Based on the localization of Olfr558, we hypothesized that Olfr558 plays a role in blood pressure regulation. We find that sex differences in blood pressure are intact in Olfr558 wildtype (WT) mice, but, are absent in Olfr558 knockout (KO) mice. We find that male KO mice have lowered diastolic blood pressure, decreased renin expression and activity, and altered vascular reactivity. Female KO mice exhibit increased blood pressure and increased pulse wave velocity, indicating increased vascular stiffness. The human ortholog of Olfr558, OR51E1, was previously identified as a locus associated with diastolic blood pressure. We report here that a rare OR51E1 missense variant has a statistically significant sex interaction effect with diastolic blood pressure, increasing diastolic blood pressure in women but decreasing it in men. In addition, we characterize how two different clinically relevant OR51E1 variants influence OR51E1 signaling in vitro. In sum, our findings demonstrate an evolutionarily conserved role for Olfr558/OR51E1 to mediate sex differences in blood pressure by altering renin, vascular reactivity, and arterial stiffness.

physiology↗

bioRxiv2019

Multi-ancestry GWAS of the electrocardiographic PR interval identifies 210 loci underlying cardiac conduction

The electrocardiographic PR interval reflects atrioventricular conduction, and is associated with conduction abnormalities, pacemaker implantation, atrial fibrillation (AF), and cardiovascular mortality1,2. We performed multi-ancestry (N=293,051) and European only (N=271,570) genome-wide association (GWAS) meta-analyses for the PR interval, discovering 210 loci of which 149 are novel. Variants at all loci nearly doubled the percentage of heritability explained, from 33.5% to 62.6%. We observed enrichment for genes involved in cardiac muscle development/contraction and the cytoskeleton highlighting key regulation processes for atrioventricular conduction. Additionally, 19 novel loci harbour genes underlying inherited monogenic heart diseases suggesting the role of these genes in cardiovascular pathology in the general population. We showed that polygenic predisposition to PR interval duration is an endophenotype for cardiovascular disease risk, including distal conduction disease, AF, atrioventricular pre-excitation, non-ischemic cardiomyopathy, and coronary heart disease. These findings advance our understanding of the polygenic basis of cardiac conduction, and the genetic relationship between PR interval duration and cardiovascular disease.

genetics↗

bioRxiv2019

KCND3 is a novel susceptibility locus for early repolarization

The presence of an early repolarization pattern (ERP) on the surface electrocardiogram (ECG) is associated with risk of ventricular fibrillation and sudden cardiac death. Family studies have shown that ERP is a highly heritable trait but molecular genetic determinants are unknown. We assessed the ERP in 12-lead ECGs of 39,456 individuals and conducted a two-stage meta-analysis of genome-wide association studies (GWAS). In the discovery phase, we included 2,181 cases and 23,641 controls from eight European ancestry studies and identified 19 genome-wide significant (p<5E-8) variants in the KCND3 (potassium voltage gated channel subfamily D member 3) gene with a p-value of 4.6E-10. Replication of two loci in four additional studies including 1,124 cases and 12,510 controls confirmed the association at the KCND3 gene locus with a pooled odds ratio of 0.82, p=7.7E-12 (rs1545300 minor allele T). A subsequent GWAS meta-analysis combining all samples did not reveal additional loci. The lead SNP of the discovery stage (rs12090194) was in strong linkage disequilibrium with rs1545300 (r2=0.96, D=1). Summary statistics based conditional analysis did not reveal any secondary signals. Co-localization analyses indicate causal effects of KCND3 gene expression levels on ERP in both the left ventricle of the heart and in tibial artery.\n\nIn this study we identified for the first time a genome-wide significant association of a genetic variant with ERP. Our findings of a locus in the KCND3 gene not only provide insights into the genetic determinants but also into the pathophysiological mechanism of ERP, revealing a promising candidate for functional studies.

genetics↗

bioRxiv2017

Genetic analysis of over one million people identifies 535 novel loci for blood pressure.

High blood pressure is the foremost heritable global risk factor for cardiovascular disease. We report the largest genetic association study of blood pressure traits to date (systolic, diastolic, pulse pressure) in over one million people of European ancestry. We identify 535 novel blood pressure loci that not only offer new biological insights into blood pressure regulation but also reveal shared loci influencing lifestyle exposures. Our findings offer the potential for a precision medicine strategy for future cardiovascular disease prevention.

genetics↗