Abstract
Myocardial infarction (MI) is characterized by massive cardiomyocytes death and cardiac dysfunction, and effective therapies to achieve cardioprotection are sorely needed. Here we reported that flavin containing monooxygenase 2 (FMO2) level was markedly increased in cardiomyocytes both in ex vivo and in vivo models of ischemia injury. Genetic deletion of FMO2 resulted in reduced cardiomyocyte survival and enhanced cardiac dysfunction, whereas cardiomyocyte-specific FMO2 overexpression exerted a protective effect in infarcted rat hearts. Mechanistically, FMO2 inhibited the activation of endoplasmic reticulum (ER) stress-induced apoptotic proteins, including caspase 12 and C/EBP homologous protein (CHOP), by down-regulating unfolded protein response (UPR) pathway. Furthermore, we identified FMO2 as a chaperone that catalyzed disulfide-bond formation in unfolded/misfolded proteins through its GVSG motif. GVSG-mutated FMO2 failed to catalyze disulfide-bond formation and lost its protection against ER stress and cardiomyocyte death. Finally, we demonstrated the protective effect of FMO2 in human induced pluripotent stem cell–derived cardiomyocyte (hiPSC-CM) model. Collectively, this study highlights FMO2 as a key modulator of oxidative protein folding in cardiomyocytes and underscores its therapeutic potential for treating ischemic heart disease.
Authors
Qingnian Liu, Jiniu Huang, Hao Ding, Yue Tao, Jinliang Nan, Changchen Xiao, Yingchao Wang, Rongrong Wu, Cheng Ni, Zhiwei Zhong, Wei Zhu, Jinghai Chen, Chenyun Zhang, Xiao He, Danyang Xiong, Xinyang Hu, Jian'an Wang
Abstract
Hypertrophic and dilated cardiomyopathies (HCM and DCM, respectively) are inherited disorders that may be caused by mutations to the same sarcomeric protein but have completely different clinical phenotypes. The precise mechanisms by which point mutations within the same gene bring about phenotypic diversity remain unclear. Our objective has been to develop a mechanistic explanation of diverging phenotypes in two TPM1 mutations, E62Q (HCM) and E54K (DCM). Drawing on data from the literature and experiments with stem cell-derived cardiomyocytes expressing the TPM1 mutations of interest, we constructed computational simulations that provide plausible explanations of the distinct muscle contractility caused by each variant. In E62Q, increased calcium sensitivity and hypercontractility was explained most accurately by a reduction in effective molecular stiffness of tropomyosin and alterations in its interactions with the actin thin filament that favor the ‘closed’ regulatory state. By contrast, the E54K mutation appeared to act via long-range allosteric interactions to increase the association rate of the C-terminal troponin I mobile domain to tropomyosin/actin. These mutation-linked molecular events produced diverging alterations in gene expression that can be observed in human engineered heart tissues. Modulators of myosin activity confirmed our proposed mechanisms by rescuing normal contractile behavior in accordance with predictions.
Authors
Saiti S. Halder, Michael J. Rynkiewicz, Lynne Kim, Meaghan Barry, Ahmed G.A. Zied, Lorenzo R. Sewanan, Jonathan A. Kirk, Jeffrey R. Moore, William Lehman, Stuart G. Campbell
Abstract
Fibrosis represents the uncontrolled replacement of parenchymal tissue with extracellular matrix (ECM) produced by myofibroblasts. While genetic fate-tracing and single-cell RNA-Seq technologies have helped elucidate fibroblast heterogeneity and ontogeny beyond fibroblast to myofibroblast differentiation, newly identified fibroblast populations remain ill defined, with respect to both the molecular cues driving their differentiation and their subsequent role in fibrosis. Using an unbiased approach, we identified the metalloprotease ADAMTS12 as a fibroblast-specific gene that is strongly upregulated during active fibrogenesis in humans and mice. Functional in vivo KO studies in mice confirmed that Adamts12 was critical during fibrogenesis in both heart and kidney. Mechanistically, using a combination of spatial transcriptomics and expression of catalytically active or inactive ADAMTS12, we demonstrated that the active protease of ADAMTS12 shaped ECM composition and cleaved hemicentin 1 (HMCN1) to enable the activation and migration of a distinct injury-responsive fibroblast subset defined by aberrant high JAK/STAT signaling.
Authors
Konrad Hoeft, Lars Koch, Susanne Ziegler, Ling Zhang, Steffen Luetke, Maria C. Tanzer, Debashish Mohanta, David Schumacher, Felix Schreibing, Qingqing Long, Hyojin Kim, Barbara M. Klinkhammer, Carla Schikarski, Sidrah Maryam, Mathijs Baens, Juliane Hermann, Sarah Krieg, Fabian Peisker, Laura De Laporte, Gideon J.L. Schaefer, Sylvia Menzel, Joachim Jankowski, Benjamin D. Humphreys, Adam Wahida, Rebekka K. Schneider, Matthias Versele, Peter Boor, Matthias Mann, Gerhard Sengle, Sikander Hayat, Rafael Kramann
Abstract
BACKGROUND. Recent studies conducted in COVID-19 survivors suggest that SARS-CoV-2 infection is associated with an increased risk of dyslipidemia. However, it remains unclear whether this augmented risk is confirmed in the general population and how this phenomenon is impacting the overall burden of cardiometabolic diseases. METHODS. To address these aspects, we conducted a 6-year longitudinal study to examine the broader effects of COVID-19 on dyslipidemia incidence within a real-world population (228,266 subjects) residing in Naples, Southern Italy. The pre-COVID-19 and the COVID-19 groups were balanced for demographic and clinical factors using propensity score matching. RESULTS. Our analysis spans over a period of three years during the pandemic (2020–2022), comparing dyslipidemia incidence with pre-pandemic data (2017–2019), with a follow-up time of at least 1,095 days corresponding to 21,349,215 person-years. During the COVID-19 period we detected an increased risk of developing any dyslipidemia when compared with the pre-COVID-19 triennium (OR = 1.29, 95% CI 1.19–1.39). Importantly, these estimates were adjusted for comorbidities by a multivariate analysis. CONCLUSIONS. Taken together, our data reveal a notable rise in dyslipidemia incidence amid the COVID-19 pandemic, suggesting to establish specialized clinical monitoring protocols for COVID-19 survivors to mitigate the risk of dyslipidemia development.
Authors
Valentina Trimarco, Raffaele Izzo, Stanislovas S. Jankauskas, Mario Fordellone, Giuseppe Signoriello, Maria Virginia Manzi, Maria Lembo, Paola Gallo, Giovanni Esposito, Roberto Piccinocchi, Francesco Rozza, Carmine Morisco, Pasquale Mone, Gaetano Piccinocchi, Fahimeh Varzideh, Bruno Trimarco, Gaetano Santulli
Abstract
Cardiac macrophages/monocytes participate in maintaining homeostasis and orchestrating cardiac responses upon injury. However, the function of specific macrophage/monocyte subtypes and the related cell fate commitment mechanisms remain elusive in regenerative and nonregenerative hearts due to their cellular heterogeneities. Using spatiotemporal single-cell epigenomic analysis of cardiac macrophages/monocytes in regenerative (P1) and nonregenerative (P10) mouse hearts post injury, we found that P1 hearts accumulate reparative Arg1+ macrophages, while proinflammatory S100a9+Ly6c+ monocytes are uniquely abundant during nonregenerative remodeling. Moreover, blocking chemokine CXCR2 to inhibit the specification of the S100a9+Ly6c+-biased inflammatory fate in P10 hearts resulted in elevated wound repair responses and marked improvements in cardiac function after injury. Single-cell RNA-seq further confirmed an increased Arg1+ macrophage subpopulation after CXCR2 blockade, which was accomplished by increased expression of wound repair-related genes and reduced expression of proinflammatory genes. Collectively, our findings provide instructive insights into the molecular mechanisms underlying the function and fate specification of heterogeneous macrophages/monocytes during cardiac repair and identify potential therapeutic targets for myocardial infarction.
Authors
Mingzhu Fu, Shengtao Jia, Longhui Xu, Xin Li, Yufang Lv, Yulong Zhong, Shanshan Ai
Abstract
Obesity is linked to an increased risk of atrial fibrillation (AF) via increased oxidative stress. While NADPH oxidase II (NOX2), a major source of oxidative stress and reactive oxygen species (ROS) in the heart predisposes to AF, the underlying mechanisms remain unclear. Here, we studied NOX2-mediated ROS production in obesity-mediated AF using Nox2-knock-out (KO) mice and mature human induced pluripotent stem cell-derived atrial cardiomyocytes (hiPSC-aCMs). Diet-induced obesity (DIO) mice and hiPSC-aCMs treated with palmitic acid (PA) were infused with a NOX blocker (apocynin) and a NOX2-specific inhibitor, respectively. We showed that NOX2 inhibition normalized atrial action potential duration and abrogated obesity-mediated ion channel remodeling with reduced AF burden. Unbiased transcriptomics analysis revealed that NOX2 mediates atrial remodeling in obesity-mediated AF in DIO mice, PA-treated hiPSC-aCMs, and human atrial tissue from obese individuals by upregulation of paired-like homeodomain transcription factor 2 (PITX2). Furthermore, hiPSC-aCMs treated with hydrogen peroxide, a NOX2 surrogate, displayed increased PITX2 expression, establishing a mechanistic link between increased NOX2-mediated ROS production and modulation of PITX2. Our findings offer insights into possible mechanisms through which obesity triggers AF and support NOX2 inhibition as a potential novel prophylactic or adjunctive therapy for patients with obesity-mediated AF.
Authors
Arvind Sridhar, Jaime DeSantiago, Hanna Chen, Mahmud Arif Pavel, Olivia Ly, Asia Owais, Miles Barney, Jordan Jousma, Sarath Babu Nukala, Khaled Abdelhady, Malek Massad, Lona Ernst Rizkallah, Sang-Ging Ong, Jalees Rehman, Dawood Darbar
Abstract
Posttranslational modifications can enhance immunogenicity of self-proteins. In several conditions, including hypertension, systemic lupus erythematosus, and heart failure, isolevuglandins (IsoLGs) are formed by lipid peroxidation and covalently bond with protein lysine residues. Here, we show that the murine class I major histocompatibility complex (MHC-I) variant H-2Db uniquely presents isoLG-modified peptides and developed a computational pipeline that identifies structural features for MHC-I accommodation of such peptides. We identified isoLG-adducted peptides from renal proteins, including sodium glucose transporter 2, cadherin 16, Kelch domain–containing protein 7A, and solute carrier family 23, that are recognized by CD8+ T cells in tissues of hypertensive mice, induce T cell proliferation in vitro, and prime hypertension after adoptive transfer. Finally, we find patterns of isoLG-adducted antigen restriction in class I human leukocyte antigens that are similar to those in murine analogs. Thus, we have used a combined computational and experimental approach to define likely antigenic peptides in hypertension.
Authors
Nathaniel Bloodworth, Wei Chen, Kuniko Hunter, David Patrick, Amy Palubinsky, Elizabeth Phillips, Daniel Roeth, Markus Kalkum, Simon Mallal, Sean Davies, Mingfang Ao, Rocco Moretti, Jens Meiler, David G. Harrison
Abstract
Authors
Benjamin J. Landis, Benjamin M. Helm, Matthew D. Durbin, Lindsey R. Helvaty, Jeremy L. Herrmann, Michael Johansen, Gabrielle C. Geddes, Stephanie M. Ware
Abstract
Research advances over the past 30 years have confirmed a critical role for genetics in the etiology of dilated cardiomyopathies (DCMs). However, full knowledge of the genetic architecture of DCM remains incomplete. We identified candidate DCM causal gene, C10orf71, in a large family with 8 patients with DCM by whole-exome sequencing. Four loss-of-function variants of C10orf71 were subsequently identified in an additional group of492 patients with sporadic DCM from 2 independent cohorts. C10orf71 was found to be an intrinsically disordered protein specifically expressed in cardiomyocytes. C10orf71-KO mice had abnormal heart morphogenesis during embryonic development and cardiac dysfunction as adults with altered expression and splicing of contractile cardiac genes. C10orf71-null cardiomyocytes exhibited impaired contractile function with unaffected sarcomere structure. Cardiomyocytes and heart organoids derived from human induced pluripotent stem cells with C10orf71 frameshift variants also had contractile defects with normal electrophysiological activity. A rescue study using a cardiac myosin activator, omecamtiv mecarbil, restored contractile function in C10orf71-KO mice. These data support C10orf71 as a causal gene for DCM by contributing to the contractile function of cardiomyocytes. Mutation-specific pathophysiology may suggest therapeutic targets and more individualized therapy.
Authors
Yang Li, Ke Ma, Zhujun Dong, Shijuan Gao, Jing Zhang, Shan Huang, Jie Yang, Guangming Fang, Yujie Li, Xiaowei Li, Carrie Welch, Emily L. Griffin, Prema Ramaswamy, Zaheer Valivullah, Xiuying Liu, Jianzeng Dong, Dao Wen Wang, Jie Du, Wendy K. Chung, Yulin Li
Abstract
Trisomy 21 (T21), a recurrent aneuploidy occurring in 1:800 births, predisposes to congenital heart disease (CHD) and multiple extracardiac phenotypes. Despite a definitive genetic etiology, the mechanisms by which T21 perturbs development and homeostasis remain poorly understood. We compared the transcriptome of CHD tissues from 49 patients with T21 and 226 with euploid CHD (eCHD). We resolved cell lineages that misexpressed T21 transcripts by cardiac single-nucleus RNA sequencing and RNA in situ hybridization. Compared with eCHD samples, T21 samples had increased chr21 gene expression; 11-fold-greater levels (P = 1.2 × 10–8) of SOST (chr17), encoding the Wnt inhibitor sclerostin; and 1.4-fold-higher levels (P = 8.7 × 10–8) of the SOST transcriptional activator ZNF467 (chr7). Euploid and T21 cardiac endothelial cells coexpressed SOST and ZNF467; however, T21 endothelial cells expressed 6.9-fold more SOST than euploid endothelial cells (P = 2.7 × 10–27). Wnt pathway genes were downregulated in T21 endothelial cells. Expression of DSCAM, residing within the chr21 CHD critical region, correlated with SOST (P = 1.9 × 10–5) and ZNF467 (P = 2.9 × 10–4). Deletion of DSCAM from T21 endothelial cells derived from human induced pluripotent stem cells diminished sclerostin secretion. As Wnt signaling is critical for atrioventricular canal formation, bone health, and pulmonary vascular homeostasis, we concluded that T21-mediated increased sclerostin levels would inappropriately inhibit Wnt activities and promote Down syndrome phenotypes. These findings imply therapeutic potential for anti-sclerostin antibodies in T21.
Authors
David M. McKean, Qi Zhang, Priyanka Narayan, Sarah U. Morton, Viktoria Strohmenger, Vi T. Tang, Sophie McAllister, Ananya Sharma, Daniel Quiat, Daniel Reichart, Daniel M. DeLaughter, Hiroko Wakimoto, Joshua M. Gorham, Kemar Brown, Barbara McDonough, Jon A. Willcox, Min Young Jang, Steven R. DePalma, Tarsha Ward, Pediatric Cardiac Genomics Consortium Investigators, Richard Kim, John D. Cleveland, J.G. Seidman, Christine E. Seidman
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)