Articles

Grune et al. show that hypokalemic mice develop spontaneous ventricular tachycardia after myocardial infarction, and they use this model to dissect the role of immune cells in arrhythmia: neutrophils increase ventricular tachycardia, partly by promoting reactive oxygen species production, whereas efferocytic macrophages play a protective role.

Using rat and mouse models of pulmonary hypertension and patients’ data, Shu, Liu, Zhou et al. show that the concomitant increase in immunoglobulin E (IgE) and mast cells expressing the effector receptor FcεRIα has an important role in pulmonary vascular remodeling, and genetic and pharmacological inhibition of the IgE–FcεRIα signaling alleviated the progression of pulmonary hypertension in animal models.

Pianca and Sacchi et al. unveil an important role for glucocorticoids and their receptor (GR) in cardiomyocyte cytoarchitectural/metabolic maturation, cell cycle exit and loss of regenerative ability, and they propose GR antagonization as a strategy for heart regeneration.

Yu et al. show that Piezo1 is the stretch-activated mechanosensor that provides the calcium source to activate TRPM4 and the downstream CaMKII-HDAC4-MEF2 pathway, a key mediator in the cardiomyocytes’ hypertrophic response in pressure overload models.

Using high-resolution confocal images and computational surface mapping, Esteban et al. provide a detailed pseudodynamic atlas of early heart tube development (E7.5–E8.5), develop a morphometric staging system based on landmark curves and distances in the surface of the tissues and identify parameters that can be used for precise embryo staging across different labs. This morphometric analysis reveals early signs of left–right asymmetry, before the cardiac looping stage, which is regulated by the Nodal signaling pathway.

Increased late sodium current due to the disruption of voltage-gated sodium channel inactivation is a common pathogenic mechanism in different arrhythmogenic syndromes. Chakouri et al. show that fibroblast growth factor homologous factors (FHFs) modulate pathogenic late sodium current in an isoform-specific way, and leverage this observation to design and test a prototype of inhibitor peptide based on a protein domain from an inhibitory FHF isoform.

Bernier-Latmani et al. report a mechanism for maintaining colon cancer-associated vasculature, in which colon endothelial apelin signaling promotes migration of distant venous endothelial cells toward the tumor progenitor cell niche to sustain VEGFA-independent vascular expansion and a normoxic microenvironment.

Corti et al. show that the proteoglycan Syndecan-2 (Sdc2) regulates the interaction between phosphatase DEP1 and the vascular endothelial growth factor receptor VEGFR2. Depletion or antibody-mediated inhibition of Sdc2 causes compromised internalization of DEP1, and excessive expression of DEP1 in the membrane results in large dephosphorylation specifically of VEGFR2 Y951 residue, leading to reduced VEGF-mediated permeabilization without affecting other VEGF-mediated functions, with beneficial effects in animal models of skin edema and brain focal stroke.

Atherosclerosis is accompanied by an autoimmune response that includes CD4 T cells recognizing epitopes in apolipoprotein B (APOB). Saigusa et al. analyzed the transcriptomes and T cell receptors of APOB-specific CD4 T cells by single-cell RNA sequencing using MHC-II tetramers in women with atherosclerosis, and showed that APOB-specific regulatory T cells switch to a more memory-like phenotype in atherosclerosis.

Wang et al. analyze the metabolome and lipidome of heart and plasma samples from patients with HCM and healthy individuals and identify panels of metabolites that can be used as diagnostic biomarkers of HCM or predictors of HCM patient survival; patients are stratified into three groups with distinct cardiac function and survival and identify metabolic pathways that are greatly affected in patients with HCM, suggesting that targeting the pentose phosphate pathway and oxidative stress may represent effective ways to treat HCM.

Huang et al. show that myocardial infarction (MI)-associated vasculature is structurally and functionally abnormal, impeding vessel function and cardiac repair in mice. Analyses of the transcriptome of the cardiac endothelium after MI identify a PDGF–NF-κB–HIF-1α Snail axis responsible for mesenchymal transformation of endothelial cells and show that genetic ablation or targeted disruption of PDGF signaling normalizes vasculature and improves cardiac function recovery after MI.

Cheng et al. show that smooth muscle cell (SMC)-specific deletion of Smad3 influences the fate of de-differentiated SMCs in atherosclerotic plaques in vivo, promoting both a pro-remodeling SMC transition phenotype and expansion of the SMC-derived chondromyocyte population. These cellular changes are associated with increased outward remodeling and plaque calcification.

O’Regan and colleagues use deep-learning cardiac motion analysis in participants of the UK Biobank to measure diastolic functional traits and perform a genome-wide association study to generate insights into the genetic and environmental factors that influence diastolic function.

Popescu et al. developed a deep learning approach that blends neural networks and survival analysis to predict patient-specific survival curves from raw contrast-enhanced cardiac magnetic resonance images and clinical covariates for patients with ischemic heart disease to offer accurate arrhythmic sudden death predictions.

Zong and colleagues reveal a critical role for the ion channel TRPM2 in macrophages through mediating reactive oxygen species production, inflammasome activation, oxidized LDL uptake and subsequently inflammatory responses, which they show is mediated by CD36 activity, thereby establishing a mutually regulating and positive feedback mechanism between CD36 and TRPM2 in atherogenesis.

Jarr and colleagues show that statins augment efferocytosis by inhibiting the nuclear translocation of NF-κB1 p50 and suppressing the expression of the key ‘don’t-eat-me’ molecule CD47, which in part explains the pleiotropic effects of statins and provides a basis for future translational efforts.

In a multicenter research program coordinated by the International Mouse Phenotyping Consortium, Spielmann et al. analyze the cardiac function and structure in ~4,000 monogenic mutant mice and identify 705 mouse genes involved in cardiac function, 75% of which have not been previously linked to cardiac heritable disease in humans. Using the UK Biobank human data, the authors validate the link between cardiovascular disease and some of the newly identified genes to illustrate the resource value and potential of their mutant mouse collection.

Song and colleagues show that FDA-approved cough suppressant dextromethorphan could be used as an agonist of sigma non-opioid intracellular receptor 1 (SIGMAR1) to normalize the action potential in human cellular models and a mouse model of Timothy syndrome, a congenital disease with no available treatment. The researchers also show that dextromethorphan normalizes the action potential in human cellular models of two additional inherited cardiac arrhythmias: long QT syndrome types 1 and 2, which are caused by mutations in different genes.

Hernandez et al. show that aortic intima resident macrophages (Mac^AIR) seed the mouse aorta at birth, self-replicate and line the aortic lumen together with the endothelium, protecting the aorta from clot formation in regions of disturbed flow by clearing fibrin deposits and blunting thrombin activity.

Koplev et al. apply interactive system analyses to infer and characterize gene-regulatory networks (GRNs) active within and across tissues that cause cardiometabolic disease and coronary artery disease (CAD). By including GWAS in the integrative analysis, the provided multiorgan framework of GRNs is suggested to explain significantly more heritability of CAD than what has been achieved by analyzing GWAS alone.