Hypertrophic cardiomyopathy (HCM) is the most prominent cause of sudden cardiac death in young individuals. Due to heterogeneity in the clinical manifestations, conventional HCM drugs have limitations for mitochondrial hypertrophic cardiomyopathy. Discovering more effective compounds would be of substantial benefit for further elucidating the pathogenic mechanisms of HCM and treating patients with this condition. We previously reported the MT-RNR2 variant associated with HCM that results in mitochondrial dysfunction. Here, we screened a mitochondria-associated compound library by quantifying the mitochondrial membrane potential of HCM cybrids and the survival rate of HCM induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) in galactose media. 1-Deoxynojirimycin (DNJ) was identified to rescue mitochondrial function by targeting optic atrophy protein 1 (OPA1) to promote its oligomerization, leading to reconstruction of the mitochondrial cristae. DNJ treatment further recovered the physiological properties of HCM iPSC-CMs by improving Ca2+ homeostasis and electrophysiological properties. An angiotensin II-induced cardiac hypertrophy mouse model further verified the efficacy of DNJ in promoting cardiac mitochondrial function and alleviating cardiac hypertrophy in vivo. These results demonstrated that DNJ could be a potential mitochondrial rescue agent for mitochondrial hypertrophic cardiomyopathy. Our findings will help elucidate the mechanism of HCM and provide a potential therapeutic strategy.
Qianqian Zhuang, Fengfeng Guo, Lei Fu, Yufei Dong, Shaofang Xie, Xue Ding, Shuangyi Hu, Xuanhao D. Zhou, Yangwei Jiang, Hui Zhou, Yue Qiu, Zhaoying Lei, Mengyao Li, Huajian Cai, Mingjie Fan, Lingjie Sang, Yong Fu, Dong Zhang, Aifu Lin, Xu Li, Tilo Kunath, Ruhong Zhou, Ping Liang, Zhong Liu, Qingfeng Yan
Despite the prevalence of pericytes in the microvasculature of the heart, their role during ischemia-induced remodeling remains unclear. We used multiple lineage-tracing mouse models and found that pericytes migrated to the injury site and expressed profibrotic genes, coinciding with increased vessel leakage after myocardial infarction (MI). Single-cell RNA-Seq of cardiac pericytes at various time points after MI revealed the temporally regulated induction of genes related to vascular permeability, extracellular matrix production, basement membrane degradation, and TGF-β signaling. Deleting TGF-β receptor 1 in chondroitin sulfate proteoglycan 4–expressing (Cspg4-expressing) cells reduced fibrosis following MI, leading to a transient improvement in the cardiac ejection fraction. Furthermore, genetic ablation of Cspg4-expressing cells resulted in excessive vascular permeability, a decline in cardiac function, and increased mortality in the second week after MI. These data reveal an essential role for cardiac pericytes in the control of vascular homeostasis and the fibrotic response after acute ischemic injury, information that will help guide the development of novel strategies to preserve vascular integrity and attenuate pathological cardiac remodeling.
Pearl Quijada, Shuin Park, Peng Zhao, Kamal S.S. Kolluri, David Wong, Kevin D. Shih, Kai Fang, Arash Pezhouman, Lingjun Wang, Ali Daraei, Matthew D. Tran, Elle M. Rathbun, Kimberly N. Burgos Villar, Maria L. Garcia-Hernandez, Thanh T.D. Pham, Charles J. Lowenstein, M. Luisa Iruela-Arispe, S. Thomas Carmichael, Eric M. Small, Reza Ardehali
Inflammation promotes adverse ventricular remodeling, a common antecedent of heart failure. Here, we set out to determine how inflammatory cells affect cardiomyocytes in the remodeling heart. Pathogenic cardiac macrophages induced an IFN response in cardiomyocytes, characterized by upregulation of the ubiquitin-like protein IFN-stimulated gene 15 (ISG15), which posttranslationally modifies its targets through a process termed ISGylation. Cardiac ISG15 is controlled by type I IFN signaling, and ISG15 or ISGylation is upregulated in mice with transverse aortic constriction or infused with angiotensin II; rats with uninephrectomy and DOCA-salt, or pulmonary artery banding; cardiomyocytes exposed to IFNs or CD4+ T cell–conditioned medium; and ventricular tissue of humans with nonischemic cardiomyopathy. By nanoscale liquid chromatography–tandem mass spectrometry, we identified the myofibrillar protein filamin-C as an ISGylation target. ISG15 deficiency preserved cardiac function in mice with transverse aortic constriction and led to improved recovery of mouse hearts ex vivo. Metabolomics revealed that ISG15 regulates cardiac amino acid metabolism, whereas ISG15 deficiency prevented misfolded filamin-C accumulation and induced cardiomyocyte autophagy. In sum, ISG15 upregulation is a feature of pathological ventricular remodeling, and protein ISGylation is an inflammation-induced posttranslational modification that may contribute to heart failure development by altering cardiomyocyte protein turnover.
Veera Ganesh Yerra, Sri Nagarjun Batchu, Harmandeep Kaur, MD Golam Kabir, Youan Liu, Suzanne L. Advani, Duc Tin Tran, Shadi Sadeghian, Phelopater Sedrak, Filio Billia, Uros Kuzmanov, Anthony O. Gramolini, Deema O. Qasrawi, Evgeniy V. Petrotchenko, Christoph H. Borchers, Kim A. Connelly, Andrew Advani
Plasma IL-6 is elevated after myocardial infarction (MI) and is associated with increased morbidity and mortality. Which cardiac cell type preferentially contributes to IL-6 and how its production is regulated is largely unknown. Here, we studied the cellular source and purinergic regulation of IL-6 formation in a murine MI model. IL-6, measured in various cell types in post MI hearts by qPCR, RNAscope and at protein level, was preferentially formed by fibroblasts (CFs). scRNAseq in infarcted mouse and human hearts confirmed this finding. Adenosine stimulated fibroblast IL-6 formation via A2bR in a Gq-dependent manner. CFs highly expressed Adora2b, rapidly degraded extracellular ATP to AMP but lacked CD73. In mice and humans Adora2B was also mainly expressed by fibroblasts (scRNAseq). Global IL-6 formation was assessed in isolated hearts in mice lacking CD73 on T-cells (CD4CD73-/-) a condition known to be associated with adverse cardiac remodeling. The ischemia-induced release of IL-6 was strongly attenuated in CD4CD73-/- mice, suggesting adenosine-mediated modulation. Together this demonstrates that post-MI IL-6 is mainly derived from activated CFs and is controlled by T-cell derived adenosine. Purinergic metabolic cooperation between CFs and T-cells is a novel mechanism with therapeutic potential which modulates IL6 formation by the heart.
Christina Alter, Anne Sophie Henseler, Christoph Owenier, Julia Hesse, Zhaoping Ding, Tobias Lautwein, Jasmin Bahr, Sikander Hayat, Rafael Kramann, Eva Kostenis, Jürgen Scheller, Jürgen Schrader
During development of heart failure, capacity for cardiomyocyte fatty acid oxidation (FAO) and ATP production is progressively diminished contributing to pathologic cardiac hypertrophy and contractile dysfunction. Receptor interacting protein 140 (RIP140; Nrip1) has been shown to function as a transcriptional co-repressor of oxidative metabolism. We found that mice with striated muscle deficiency of RIP140 (strNrip1-/-) exhibit increased expression of a broad array of genes involved in mitochondrial energy metabolism and contractile function in heart and skeletal muscle. strNrip1-/- mice were resistant to the development of pressure overload-induced cardiac hypertrophy, and cardiomyocyte-specific RIP140 deficient (csNrip1-/-) mice were defended against development of heart failure caused by pressure overload combined with myocardial infarction. Genomic enhancers activated by RIP140 deficiency in cardiomyocytes were enriched in binding motifs for transcriptional regulators of mitochondrial function (estrogen-related receptor) and cardiac contractile proteins (myocyte enhancer factor 2). Consistent with a role in the control of cardiac fatty acid oxidation, loss of RIP140 in heart resulted in augmented triacylglyceride turnover and FA utilization. We conclude that RIP140 functions as a suppressor of a transcriptional regulatory network that controls cardiac fuel metabolism and contractile function, representing a potential therapeutic target for heart failure.
Tsunehisa Yamamoto, Santosh K. Maurya, Elizabeth Pruzinsky, Kirill Batmanov, Yang Xiao, Sarah M. Sulon, Tomoya Sakamoto, Yang Wang, Ling Lai, Kendra S. McDaid, Swapnil V. Shewale, Teresa C. Leone, Timothy R. Koves, Deborah M. Muoio, Pieterjan Dierickx, Mitchell A. Lazar, E. Douglas Lewandowski, Daniel P. Kelly
Calmodulin (CaM) plays critical roles in cardiomyocytes, regulating Na+ (NaV) and L-type Ca2+ channels (LTCC). LTCC dysregulation by mutant CaMs has been implicated in action potential duration (APD) prolongation and arrhythmogenic long QT (LQT) syndrome. Intriguingly, D96V-CaM prolongs APD more than other LQT-associated CaMs despite inducing comparable levels of LTCC dysfunction, suggesting dysregulation of other depolarizing channels. Here, we provide evidence implicating NaV dysregulation within transverse (T)-tubules in D96V-CaM-associated arrhythmias. D96V-CaM induces pro-arrhythmic late Na+ current (INa) by impairing inactivation of NaV1.6, but not the predominant cardiac NaV isoform, NaV1.5. We investigated arrhythmia mechanisms using mice with cardiac-specific expression of D96V-CaM (cD96V). Super-resolution microscopy revealed close proximity of NaV1.6 and RyR2 within T-tubules. NaV1.6 density within these regions increased in cD96V relative to WT. Consistent with NaV1.6 dysregulation by D96V-CaM in these regions, we observed increased late NaV activity in T-tubules. The resulting late INa promoted aberrant Ca2+ release and prolonged APD in myocytes, leading to LQT and ventricular tachycardia (VT) in vivo. Cardiac-specific NaV1.6 knockout protected cD96V mice from increased T-tubular late NaV activity, and its arrhythmogenic consequences. In summary, we demonstrate that D96V-CaM promotes arrhythmias by dysregulating LTCC and NaV1.6 within T-tubules and thereby, facilitating aberrant Ca2+ release.
Mikhail Tarasov, Heather L. Struckman, Yusuf Olgar, Alec Miller, Mustafa Demirtas, Vladimir Bogdanov, Radmila Terentyeva, Andrew M. Soltisz, Xiaolei Meng, Dennison Min, Galina Sakuta, Izabella Dunlap, Antonia D. Duran, Mark P. Foster, Jonathan P. Davis, Dmitry Terentyev, Sándor Györke, Rengasayee Veeraraghavan, Przemysław B. Radwański
Genetic variants in the third intron of the PRDM6 gene have been associated with blood pressure traits in multiple genome-wide association studies (GWAS). By combining fine mapping, massive-ly parallel reporter assays, and gene editing we identified the causal variants for hypertension as super-enhancers that drive the expression of PRDM6 and are partly regulated by STAT1. The het-erozygous SMC-specific Prdm6 knockout mice (Prdm6fl/+ Sm22Cre) exhibited a markedly high-er number of renin-producing cells in the kidneys at embryonic day 18.5 compared to wild-type littermates and developed salt-induced systemic hypertension that was completely responsive to the renin inhibitor aliskiren. Strikingly, RNA-seq analysis of the mice aorta identified a network of PRDM6-regulated genes that are located in GWAS-associated loci for blood pressure, most nota-bly Sox6, which modulates renin-expression in the kidney. Accordingly, the smooth muscle cell-specific disruption of Sox6 in Prdm6fl/+ Sm22Cre mice resulted in a dramatic reduction of renin. Fate mapping and histological studies also showed increased numbers of neural crest-derived cells accompanied by increased collagen deposition in the kidneys of Prdm6fl/+ Wnt1Cre-ZsGreen1Cre compared to wild-type mice. These findings establish the role of PRDM6 as a regulator of renin-producing cells and an attractive target for the development of antihypertensive drugs.
Kushan L. Gunawardhana, Lingjuan Hong, Trojan Rugira, Severin Uebbing, Joanna Kucharczak, Sameet Mehta, Dineth R. Karunamuni, Brenda Cabrera-Mendoza, Renato Polimanti, James P. Noonan, Arya Mani
Innate immune cells play important roles in tissue injury and repair following acute myocardial infarction (MI). Although reprogramming of macrophage metabolism has been observed during inflammation and resolution phases, the mechanistic link to macrophage phenotype is not fully understood. In this study, we found myeloid specific deletion of mitochondrial Complex I protein Ndufs4 (mKO) reproduced the proinflammatory metabolic profile in macrophages and exaggerated the response to lipopolysacharride. Moreover, mKO mice showed increased mortality, poor scar formation and worsened cardiac function 30 days post-MI. We observed a greater inflammatory response in mKO on day 1 followed by increased cell death of infiltrating macrophages and blunted transition to reparative phase during day 3-7 post-MI. Efferocytosis is markedly impaired in mKO macrophages leading to lower expression of anti-inflammatory cytokine and tissue repair factors, which suppressed the proliferation/activation of myofibroblasts in the infarct area. Mitochondria-targeted ROS scavenging rescued these impairments and improved myofibroblast function in vivo and reduced post-MI mortality in mKO mice. Together these results reveal a novel role of mitochondria in inflammation resolution and tissue repair via modulating efferocytosis and crosstalk with fibroblasts. The findings are significant for post-MI recovery as well as for other inflammatory conditions.
Shanshan Cai, Mingyue Zhao, Bo Zhou, Akira Yoshii, Darrian Bugg, Outi Villet, Anita Sahu, Gregory S. Olson, Jennifer Davis, Rong Tian
Modification of cysteine residues by oxidative and nitrosative stress affects structure and function of proteins, thereby contributing to the pathogenesis of cardiovascular disease. Although the major function of thioredoxin 1 (Trx1) is to reduce disulfide bonds, it can also act as either a denitrosylase or transnitrosylase in a context-dependent manner. Here we show that Trx1 transnitrosylates Atg7, an E1-like enzyme, thereby stimulating autophagy. Trx1 was S-nitrosylated at Cys73 when Cys32-35, the oxidoreductase catalytic center, was oxidized and forms a disulfide bond during ischemia. Unexpectedly, Atg7 Cys545-548 reduced the disulfide bond in Trx1 at Cys32-35 through thiol-disulfide exchange and this then allowed NO to be released from Cys73 in Trx1 and transferred to Atg7 at Cys402. Experiments conducted with Atg7 C402S knock-in mice showed that S-nitrosylation of Atg7 at Cys402 promotes autophagy by stimulating E1-like activity, thereby protecting the heart against ischemia. These results suggest that the thiol-disulfide exchange and the NO transfer are functionally coupled, allowing oxidized Trx1 to mediate a salutary effect during myocardial ischemia through transnitrosylation of Atg7 and stimulation of autophagy.
Narayani Nagarajan, Shin-ichi Oka, Jihoon Nah, Changgong Wu, Peiyong Zhai, Risa Mukai, Xiaoyong Xu, Sanchita Kashyap, Chun-Yang Huang, Eun-Ah Sung, Wataru Mizushima, Allen Sam Titus, Koichiro Takayama, Youssef Mourad, Jamie Francisco, Tong Liu, Tong Chen, Hong Li, Junichi Sadoshima
Comprehensive cis-regulatory landscapes are essential for accurate enhancer prediction and disease variant mapping. Although cis-regulatory element (CRE) resources exist for most tissues and organs, many rare – yet functionally important – cell types remain overlooked. Despite representing only a small fraction of the heart’s cellular biomass, the cardiac conduction system (CCS) unfailingly coordinates every life-sustaining heartbeat. To globally profile the mouse CCS cis-regulatory landscape, we genetically tagged CCS component-specific nuclei for comprehensive ATAC-seq analysis. Thus, we established a global CCS-enriched CRE database (CCS-ATAC) as a key resource for studying CCS-wide and component-specific regulatory functions. Using transcription factor (TF) motifs to construct CCS component-specific gene regulatory networks (GRNs), we identify and independently confirm several novel TF sub-networks. Highlighting the functional importance of CCS-ATAC, we also validate numerous CCS-enriched enhancer elements and suggest gene targets based on CCS single-cell RNA-seq data. Furthermore, we leverage CCS-ATAC to improve annotation of existing human variants related to cardiac rhythm and nominate a potential enhancer-target pair dysregulated by a specific SNP. Collectively, our results establish a CCS regulatory compendium, identify novel CCS enhancer elements, and illuminate potential functional associations between human genomic variants and CCS component-specific CREs.
Samadrita Bhattacharyya, Rahul K. Kollipara, Gabriela Orquera-Tornakian, Sean Goetsch, Minzhe Zhang, Cameron Perry, Boxun Li, John M. Shelton, Minoti Bhakta, Jialei Duan, Yang Xie, Guanghua Xiao, Bret M. Evers, Gary C. Hon, Ralf Kittler, Nikhil V. Munshi