Circulation: Genomic and Precision Medicine最新文献

Background: Atrial fibrillation (AF) is a common and clinically heterogeneous arrhythmia. Machine learning algorithms can define data-driven disease subtypes in an unbiased fashion, but whether these AF subgroups align with underlying mechanisms, such as polygenic liability to AF or inflammation, and associate with clinical outcomes is unclear.

Methods: We identified individuals with AF in a large biobank linked to electronic health records and genome-wide genotyping. We applied an unsupervised coclustering machine learning algorithm to 35 curated and uncorrelated clinical features to identify distinct phenotypic AF clusters. The clinical inflammatory status of the clusters was defined using measured biomarkers (CRP, ESR, WBC, Neutrophil %, Platelet count, RDW) within 6 months of first AF mention. Polygenic risk scores for AF and for cytokine levels were used to assess the genetic liability of clusters to AF and inflammation, respectively. Clinical outcomes were collected from electronic health records up to the last medical contact.

Results: The analysis included 23 271 subjects with AF, of which 6023 had available genome-wide genotyping. The machine learning algorithm identified 3 phenotypic clusters that were distinguished by increasing prevalence of comorbidities, particularly renal disease and coronary artery disease. Polygenic liability to AF across clusters was highest in the low comorbidity cluster. Clinically measured inflammatory biomarkers were highest in the high comorbidity cluster. There was no difference between groups in genetically predicted levels of inflammatory biomarkers. Cluster assignment was associated with mortality, stroke, bleeding, and use of cardiac implantable electronic devices after AF diagnosis.

Conclusions: Patients within AF subgroups identified by clustering were distinguished by comorbidity burden and associated with risk of clinically important outcomes, polygenic liability to AF, and clinical inflammation, but not with genetically predicted inflammatory cytokine levels. Our study empirically demonstrates the complementary roles of comorbidity and genetic liability as major drivers of AF phenotypic variability using hypothesis-free methods.

Background: TRPC6 (transient receptor potential canonical 6) channels, encoded by the TRPC6 gene, are widely expressed in cardiomyocytes and play a critical role in maintaining intracellular Ca²⁺ homeostasis. Variants in TRPC6 are associated with chemotherapy-related cardiomyopathy. Specifically, the TRPC6 A404V polymorphism, with a minor (404 V) allele frequency of 12% in the general population, has been identified in patients undergoing anthracycline therapy. However, the underlying mechanisms remain largely unexplored.

Methods: Using patch-clamp recordings, Ca²⁺ imaging, computational analysis, and molecular biology techniques, we assessed the effects of doxorubicin and its metabolite, doxorubicinol, on regulating TRPC6 alanine (A) at position 404 replaced by valine (V; A404V) channel expression and function in a heterologous expression system and native cardiac cells.

Results: Both additive and recessive models demonstrated a significant association between the TRPC6 A404V variant and doxorubicin-related cardiomyopathy. The TRPC6 A404V channel exhibited higher membrane expression levels compared with the wild type (WT) control. Patch-clamp recordings showed that both TRPC6 WT and A404V channels remained mostly inactive at baseline. Application of 50 μmol/L 1-oleoyl acetyl-sn-glycerol (OAG), a TRPC6 activator, significantly increased the inward- and outward-current densities of WT and A404V channels. Furthermore, a 24-hour treatment with 0.5 μmol/L doxorubicin enhanced TRPC6 mRNA expression and potentiated the OAG effects on both WT and A404V channels, with a more pronounced response in A404V channels. Treatment with 0.5 μmol/L doxorubicinol had no effect on OAG-induced current densities in either WT or A404V channels. Doxorubicin effects on intracellular Ca²⁺ levels were confirmed by Ca²⁺ imaging in native cardiac cells. Computational modeling revealed that the A404V mutation induces a conformational change in the OAG-binding pocket, enhancing its interaction with OAG in the A404V protein compared with the WT control.

Conclusions: The TRPC6 A404V is a gain-of-function variant that exhibits enhanced activity in the presence of doxorubicin. Therefore, the TRPC6 A404V variant represents a risk factor for anthracycline-induced cardiotoxicity in patients with cancer.

Background: Mavacamten has been shown to improve cardiac function and symptoms in patients with symptomatic (New York Heart Association class II-III) obstructive hypertrophic cardiomyopathy (HCM). Clinical studies suggest that mavacamten monotherapy is efficacious and has a favorable safety profile, but limited evidence exists regarding monotherapy in real-world studies. This analysis aimed to describe the effectiveness and safety outcomes of mavacamten monotherapy in the real-world COLLIGO-HCM study (Mavacamten ObservationaL Evidence Global Consortium in Hypertrophic Cardiomyopathy).

Methods: Patient-level data recorded between April 2022 and February 2025 at 7 sites across 5 countries were extracted. Adult patients with a diagnosis of HCM from 2018 onwards were eligible for inclusion if they had ≥1 mavacamten prescription after the date of diagnosis. Patients were categorized based on background therapy status during mavacamten treatment: mavacamten monotherapy or mavacamten with background therapy (down-titration or no dose modification).

Results: Overall, 278 patients were included and received mavacamten (mavacamten monotherapy, n=88; mavacamten with background therapy, n=190). At month 9, most patients achieved ≥1 New York Heart Association class improvement from baseline (mavacamten monotherapy, 60.0%; mavacamten with background therapy, 61.0%). Improvements in resting and Valsalva left ventricular outflow tract gradients from baseline to month 9 were observed in both subgroups; mean left ventricular ejection fraction through month 9 remained ≥62.0% with mavacamten monotherapy and ≥61.4% with mavacamten with background therapy. Two patients in the mavacamten monotherapy subgroup and 1 patient in the mavacamten with background therapy subgroup permanently discontinued treatment owing to left ventricular ejection fraction <50%.

Conclusions: Mavacamten monotherapy was associated with improvements in cardiac function and symptoms, and positive benefits to the risk profile over a 9-month follow-up period; this was consistent with improvements observed in patients treated with mavacamten with background therapy.

Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT06372457.

Background: ACTA2 pathogenic variants predispose to thoracic aortic disease, and a subset of variants lead to early onset atherosclerotic cardiovascular disease (ASCVD). The molecular pathway linking misfolded SMA (α-smooth muscle actin) monomers to augmented atherosclerosis-associated smooth muscle cell phenotypic modulation can be modeled in vitro by stably expressing the ACTA2 p.R149C variant in Acta2^-/- smooth muscle cells.

Methods: The Montalcino Aortic Consortium patient registry was used to identify cases with ACTA2 pathogenic/likely pathogenic missense variants. These patients were surveyed, and medical records were reviewed, to identify cases with early onset ASCVD. The variants for these cases, as well as other recurrent ACTA2 missense variants, were individually expressed in Acta2^-/- smooth muscle cells, and transcript and protein levels, HSF1 (heat shock factor 1) activation, HMGCR (3-hydroxy-3-methylglutaryl-coenzyme A reductase) expression and activity, cholesteryl ester levels, and downstream smooth muscle cell phenotypic modulation were assessed.

Results: Early onset ASCVD included coronary artery disease, peripheral vascular disease, and atherosclerotic plaques identified by imaging in the arch, descending, or abdominal aorta, along with the celiac, iliac, renal, or vertebral arteries. Twelve ACTA2 variants were identified to be associated with early onset ASCVD. Early onset ASCVD was correlated with HSF1 activation (P=0.035), cellular cholesteryl ester levels (P=0.0031), and having one family member with the specific ACTA2 pathogenic variant who had early onset ASCVD (P=0.0001).

Conclusions: Assays assessing the molecular mechanism that leads to early onset ASCVD can identify which ACTA2 pathogenic variants will trigger this condition. Ultimately, this information informs precision medical care for individuals with ACTA2 pathogenic variants, with the ultimate goal of preventing thoracic aortic disease and ASCVD.

Background: Heart failure (HF) and its main subtypes, heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF), impose an enormous health burden on elders. Assessment of the circulating proteome to illuminate pathogenesis could open new opportunities for treatment.

Methods: We conducted a plasma proteomics screen of incident HF and its subtypes in 2 older population-based cohorts, the CHS (Cardiovascular Health Study) and the AGES-RS (Aging, Gene/Environment Susceptibility-Reykjavik Study). The 2 studies used SomaLogic platforms, with 4404 aptamers in common. Multivariable Cox models were fit to evaluate individual-protein associations with HF, HFpEF, and HFrEF separately in each cohort, and study-specific associations were combined by fixed-effects meta-analysis. Replication was performed in the ARIC (Atherosclerosis Risk in Communities) cohort. Two-sample Mendelian randomization of HF and its subtypes, along with colocalization analysis, was performed to support causal inference.

Results: Among 8599 participants, 1590 experienced incident HF (536 HFpEF, 471 HFrEF). There were 119 proteins associated with HF, 15 proteins with HFpEF, and 11 proteins with HFrEF, at Bonferroni-corrected significance. Among these, 9 have never previously been identified for cardiovascular diseases, and another 61 represent new associations with incident HF or its subtypes. Of these 70 proteins, 55 of the 66 available replicated externally. Mendelian randomization analysis revealed 7 proteins genetically associated with HF at nominal significance; 2 were separately associated with HFpEF, and another 2 with HFrEF. Seven of these 9 proteins (NPDC1 [neural proliferation differentiation and control protein 1], APOF [apolipoprotein F], LMAN2 [lectin, mannose-binding 2], ADIPOQ [adiponectin], CD14 [cluster of differentiation 14], ARHGAP1 [Rho GTPase-activating protein 1], C9 [complement 9]) showed new, possibly causal associations, although we did not detect evidence for colocalization.

Conclusions: In this large-scale proteomic study involving 3 longitudinal cohorts of older adults, we identified and replicated 55 novel protein markers of HF or its subtypes, and 7 new, possibly causal proteins. These proteins may enhance risk prediction, improve understanding of pathobiology, and help prioritize targets for therapeutic development of these foremost disorders in elders.

In vitro functional modeling of genetic variants has revolutionized our understanding of which variants can cause cardiac disorders, providing insights into their molecular underpinnings. This review provides an overview of high-throughput methods used for the functional assessment of variants implicated in inherited cardiac diseases. Advances in gene-editing technology now enable the efficient generation of cells expressing individual genetic variants or libraries of variants for robust functional studies. We discuss innovative assays that can evaluate dozens or hundreds of variants sequentially. For example, the electrophysiological properties of numerous cardiac ion channel variants in genes linked to inherited arrhythmias can be characterized using automated patch clamping. The mechanical properties of cardiomyocytes expressing candidate cardiomyopathy variants can be assessed using techniques such as atomic force microscopy, traction force microscopy, and impedance-based methods. Multiplexed assays of variant effect are an emerging family of techniques that use gene-specific or general assays, combined with next-generation sequencing, to characterize hundreds or thousands of pooled genetic variants. We examine the key advantages and limitations of each method and outline future goals for the field. Innovative in vitro studies of cardiac genetic variants will enhance our understanding of variant-disease relationships and improve diagnosis, screening, and treatment options for these disorders.

Background: Myotonic dystrophy type 1 (DM1) is caused by a (CTG)n trinucleotide repeat expansion in the 3'UTR of the DMPK gene. Once expressed, repeat RNA forms toxic hairpins that sequester the MBNL (muscle blind-like) family of splicing factors. This disrupts the tissue alternative splicing landscape, triggering multisystemic manifestations-myotonia, muscle weakness, cardiac contractile defects, arrhythmia, and neurological disturbances. Although impaired mitochondrial function has been reported in the brain, skeletal muscle, and fibroblasts of patients with DM1, they have not been reported in the heart, nor have their contribution to the DM1 cardiac pathogenesis been explored. Here, we probed the bioenergetic profile of DM1-afflicted heart tissues and explored the mechanistic basis of DM1-induced cardiac bioenergetic defects.

Methods: Using an inducible, heart-specific DM1 mouse model, we performed extracellular flux analyses, measured total ATP and NAD(H) concentrations, and performed immunofluorescence staining and transmission electron microscopy to characterize DM1-induced cardiac bioenergetics and mitochondrial structural defects. We analyzed eCLIP-Seq data to identify mitochondria-related missplicing events, which we validated in human and mouse DM1 heart tissues. Finally, we used antisense oligonucleotides to replicate these events and to test the recapitulation of DM1-like bioenergetic and structural defects in vitro.

Results: DM1 induced a multistate decrease in oxygen consumption rate with a corresponding reduction in ATP and NAD(H) concentrations, indicating impaired oxidative phosphorylation in DM1-afflicted mouse hearts. We also found significant cardiac mitochondria fragmentation, which correlated with the missplicing of transcripts encoding mitochondria fission factor (Mff, encodes MFF protein) and dynamin related protein 1 (Dnm1l, encodes DRP1 protein) in DM1-afflicted human and mouse hearts. Antisense oligonucleotides-mediated redirection of Dnm1l alternative splicing reproduced DM1-like impairment in cardiac bioenergetics and mitochondrial dynamics in wild-type HL-1 cardiomyocytes.

Conclusions: Together, these findings reveal that expanded (CUG)n RNA toxicity in DM1 disrupts cardiac bioenergetics through the missplicing of critical mitochondrial fission transcripts. These misspliced transcripts represent potential therapeutic targets for improving mitochondrial function and cardiac symptoms of DM1.

Background: Congenital long-QT syndrome is most often associated with pathogenic variants in KCNQ1 encoding the pore-forming voltage-gated potassium channel subunit (KCNQ1) of the slow delayed rectifier current (I_Ks). Generation of I_Ks requires assembly of KCNQ1 with an auxiliary subunit (KCNE1) encoded by KCNE1, which is also associated with long-QT syndrome, but the causality of autosomal dominant disease is disputed. By contrast, KCNE1 is an accepted cause of recessive Jervell and Lange-Nielson syndrome type 2 (JLN2). The functional consequences of most KCNE1 variants have not been determined, and the population prevalence of JLN2 is unknown.

Methods: We determined the functional properties of 95 KCNE1 variants coexpressed with KCNQ1 in heterologous cells using high-throughput voltage-clamp recording. Experiments were conducted with each KCNE1 variant expressed in the homozygous state, and then a subset was studied in the heterozygous state. The carrier frequency of JLN2 was estimated by considering the population prevalence of dysfunctional variants.

Results: There is substantial overlap between disease-associated and population KCNE1 variants. When examined in the homozygous state, 68 KCNE1 variants exhibited significant differences in at least 1 functional property compared with wild-type KCNE1, whereas 27 variants did not significantly affect function. Most dysfunctional variants exhibited loss-of-function properties. We observed no apparent dominant-negative effects when variant and wild-type KCNE1 were coexpressed. Most variants were scored as variants of uncertain significance, and inclusion of functional data resulted in revised classifications for 14 variants. The population carrier frequency of JLN2 was calculated as 1 in 1034. Peak current density and activation voltage-dependence, but not other biophysical properties, were correlated with findings from a mutational scan of KCNE1.

Conclusions: Among 95 disease-associated or population KCNE1 variants, many exhibit abnormal functional properties without apparent dominant-negative behaviors. Using functional data, we inferred a population carrier frequency for recessive JLN2. This work helps clarify the pathogenicity of KCNE1 variants.

Background: The analysis of the circulating proteome can identify translational modifiers and biomarkers of disease expressivity and severity at a given time point. Here, we explore the relationships between protein measures implicated in cardiovascular disease and whether they mediate causal relationships between cardiovascular risk factors and disease development.

Methods: To understand the relationships between circulating biomarkers and genetic variants, medications, anthropometric traits, lifestyle factors, imaging-derived measures, and diagnoses of cardiovascular disease, we undertook in-depth analyses of measures of 9 plasma proteins with a priori roles in genetic and structural cardiovascular disease or treatment pathways (ACE2 [angiotensin-converting enzyme 2], ACTA2 [actin alpha 2], ACTN4 [actinin alpha 4], BAG3 [BAG cochaperone 3], BNP [B-type natriuretic peptide], CDKN1A [cyclin-dependent kinase inhibitor 1A], NOTCH1 [neurogenic locus notch homolog protein 1], NT-proBNP [N-terminal pro-B-type natriuretic peptide], and TNNI3 [troponin I]) from the Pharma Proteomics Project of the UK Biobank cohort (over 45 000 participants sampled at recruitment).

Results: We identified significant variability in circulating proteins with age, sex, ancestry, alcohol intake, smoking, and medication intake. Phenome-wide association studies highlighted the range of cardiovascular clinical features with relationships to protein levels. Genome-wide genetic association studies identified variants near GCKR, APOE, and SERPINA1, that modified multiple circulating protein levels (BAG3, CDKN1A, and NOTCH1). NT-proBNP and BNP levels associated with variants in BAG3. ACE2 levels were increased with a diagnosis of hypertension or diabetes, particularly in females, and were influenced by variants in genes associated with diabetes (HNF1A and HNF4A). Two-sample Mendelian randomization identified ACE2 as protective for systolic blood pressure and type-2 diabetes.

Conclusions: From a panel of circulating proteins, the results from this observational study provide evidence that ACE2 is causally protective for hypertension and diabetes. This suggests that ACE2 treatment may provide additional protection from these cardiovascular diseases. This study provides an improved understanding of the circulating pathways depicting cardiovascular disease dynamics.