Myocardial infarction (MI) leads to cardiomyocyte death, which triggers an immune response that clears debris and restores tissue integrity. In the adult heart, the immune system facilitates scar formation, which repairs the damaged myocardium but compromises cardiac function. In neonatal mice, the heart can regenerate fully without scarring following MI; however, this regenerative capacity is lost by P7. The signals that govern neonatal heart regeneration are unknown. By comparing the immune response to MI in mice at P1 and P14, we identified differences in the magnitude and kinetics of monocyte and macrophage responses to injury. Using a cell-depletion model, we determined that heart regeneration and neoangiogenesis following MI depends on neonatal macrophages. Neonates depleted of macrophages were unable to regenerate myocardia and formed fibrotic scars, resulting in reduced cardiac function and angiogenesis. Immunophenotyping and gene expression profiling of cardiac macrophages from regenerating and nonregenerating hearts indicated that regenerative macrophages have a unique polarization phenotype and secrete numerous soluble factors that may facilitate the formation of new myocardium. Our findings suggest that macrophages provide necessary signals to drive angiogenesis and regeneration of the neonatal mouse heart. Modulating inflammation may provide a key therapeutic strategy to support heart regeneration.
Arin B. Aurora, Enzo R. Porrello, Wei Tan, Ahmed I. Mahmoud, Joseph A. Hill, Rhonda Bassel-Duby, Hesham A. Sadek, Eric N. Olson
Patients with Marfan syndrome (MFS), a multisystem disorder caused by mutations in the gene encoding the extracellular matrix (ECM) protein fibrillin 1, are unusually vulnerable to stress-induced cardiac dysfunction. The prevailing view is that MFS-associated cardiac dysfunction is the result of aortic and/or valvular disease. Here, we determined that dilated cardiomyopathy (DCM) in fibrillin 1–deficient mice is a primary manifestation resulting from ECM-induced abnormal mechanosignaling by cardiomyocytes. MFS mice displayed spontaneous emergence of an enlarged and dysfunctional heart, altered physical properties of myocardial tissue, and biochemical evidence of chronic mechanical stress, including increased angiotensin II type I receptor (AT1R) signaling and abated focal adhesion kinase (FAK) activity. Partial fibrillin 1 gene inactivation in cardiomyocytes was sufficient to precipitate DCM in otherwise phenotypically normal mice. Consistent with abnormal mechanosignaling, normal cardiac size and function were restored in MFS mice treated with an AT1R antagonist and in MFS mice lacking AT1R or β-arrestin 2, but not in MFS mice treated with an angiotensin-converting enzyme inhibitor or lacking angiotensinogen. Conversely, DCM associated with abnormal AT1R and FAK signaling was the sole abnormality in mice that were haploinsufficient for both fibrillin 1 and β1 integrin. Collectively, these findings implicate fibrillin 1 in the physiological adaptation of cardiac muscle to elevated workload.
Jason R. Cook, Luca Carta, Ludovic Bénard, Elie R. Chemaly, Emily Chiu, Satish K. Rao, Thomas G. Hampton, Peter Yurchenco, Kevin D. Costa, Roger J. Hajjar, Francesco Ramirez
The transcriptome is subject to multiple changes during pathogenesis, including the
use of alternate 5′ start-sites that can affect transcription levels and
output. Current RNA sequencing techniques can assess mRNA levels, but do not robustly
detect changes in 5′ start-site use. Here, we developed a transcriptome
sequencing strategy that detects genome-wide changes in start-site usage
(5′RNA-Seq) and applied this methodology to identify regulatory events that
occur in hypertrophic cardiomyopathy (HCM). Compared with transcripts from WT mice,
92 genes had altered start-site usage in a mouse model of HCM, including
four-and-a-half LIM domains protein 1 (
Danos C. Christodoulou, Hiroko Wakimoto, Kenji Onoue, Seda Eminaga, Joshua M. Gorham, Steve R. DePalma, Daniel S. Herman, Polakit Teekakirikul, David A. Conner, David M. McKean, Andrea A. Domenighetti, Anton Aboukhalil, Stephen Chang, Gyan Srivastava, Barbara McDonough, Philip L. De Jager, Ju Chen, Martha L. Bulyk, Jochen D. Muehlschlegel, Christine E. Seidman, J.G. Seidman
TGF-β is essential for vascular development; however, excess TGF-β signaling promotes thoracic aortic aneurysm and dissection in multiple disorders, including Marfan syndrome. Since the pathology of TGF-β overactivity manifests primarily within the arterial media, it is widely assumed that suppression of TGF-β signaling in vascular smooth muscle cells will ameliorate aortic disease. We tested this hypothesis by conditional inactivation of
Wei Li, Qingle Li, Yang Jiao, Lingfeng Qin, Rahmat Ali, Jing Zhou, Jacopo Ferruzzi, Richard W. Kim, Arnar Geirsson, Harry C. Dietz, Stefan Offermanns, Jay D. Humphrey, George Tellides
Doxorubicin is an effective anticancer drug with known cardiotoxic side effects. It has been hypothesized that doxorubicin-dependent cardiotoxicity occurs through ROS production and possibly cellular iron accumulation. Here, we found that cardiotoxicity develops through the preferential accumulation of iron inside the mitochondria following doxorubicin treatment. In isolated cardiomyocytes, doxorubicin became concentrated in the mitochondria and increased both mitochondrial iron and cellular ROS levels. Overexpression of ABCB8, a mitochondrial protein that facilitates iron export, in vitro and in the hearts of transgenic mice decreased mitochondrial iron and cellular ROS and protected against doxorubicin-induced cardiomyopathy. Dexrazoxane, a drug that attenuates doxorubicin-induced cardiotoxicity, decreased mitochondrial iron levels and reversed doxorubicin-induced cardiac damage. Finally, hearts from patients with doxorubicin-induced cardiomyopathy had markedly higher mitochondrial iron levels than hearts from patients with other types of cardiomyopathies or normal cardiac function. These results suggest that the cardiotoxic effects of doxorubicin develop from mitochondrial iron accumulation and that reducing mitochondrial iron levels protects against doxorubicin-induced cardiomyopathy.
Yoshihiko Ichikawa, Mohsen Ghanefar, Marina Bayeva, Rongxue Wu, Arineh Khechaduri, Sathyamangla V. Naga Prasad, R. Kannan Mutharasan, Tejaswitha Jairaj Naik, Hossein Ardehali
Cardiac resynchronization therapy (CRT), the application of biventricular stimulation to correct discoordinate contraction, is the only heart failure treatment that enhances acute and chronic systolic function, increases cardiac work, and reduces mortality. Resting myocyte function also increases after CRT despite only modest improvement in calcium transients, suggesting that CRT may enhance myofilament calcium responsiveness. To test this hypothesis, we examined adult dogs subjected to tachypacing-induced heart failure for 6 weeks, concurrent with ventricular dyssynchrony (HFdys) or CRT. Myofilament force-calcium relationships were measured in skinned trabeculae and/or myocytes. Compared with control, maximal calcium-activated force and calcium sensitivity declined globally in HFdys; however, CRT restored both. Phosphatase PP1 induced calcium desensitization in control and CRT-treated cells, while HFdys cells were unaffected, implying that CRT enhances myofilament phosphorylation. Proteomics revealed phosphorylation sites on Z-disk and M-band proteins, which were predicted to be targets of glycogen synthase kinase-3β (GSK-3β). We found that GSK-3β was deactivated in HFdys and reactivated by CRT. Mass spectrometry of myofilament proteins from HFdys animals incubated with GSK-3β confirmed GSK-3β–dependent phosphorylation at many of the same sites observed with CRT. GSK-3β restored calcium sensitivity in HFdys, but did not affect control or CRT cells. These data indicate that CRT improves calcium responsiveness of myofilaments following HFdys through GSK-3β reactivation, identifying a therapeutic approach to enhancing contractile function.
Jonathan A. Kirk, Ronald J. Holewinski, Viola Kooij, Giulio Agnetti, Richard S. Tunin, Namthip Witayavanitkul, Pieter P. de Tombe, Wei Dong Gao, Jennifer Van Eyk, David A. Kass
Heart failure in children and adults is often the consequence of myocarditis associated with Coxsackievirus (CV) infection. Upon CV infection, enteroviral protease 2A cleaves a small number of host proteins including dystrophin, which links actin filaments to the plasma membrane of muscle fiber cells (sarcolemma). It is unknown whether protease 2A–mediated cleavage of dystrophin and subsequent disruption of the sarcolemma play a role in CV-mediated myocarditis. We generated knockin mice harboring a mutation at the protease 2A cleavage site of the dystrophin gene, which prevents dystrophin cleavage following CV infection. Compared with wild-type mice, we found that mice expressing cleavage-resistant dystrophin had a decrease in sarcolemmal disruption and cardiac virus titer following CV infection. In addition, cleavage-resistant dystrophin inhibited the cardiomyopathy induced by cardiomyocyte-restricted expression of the CV protease 2A transgene. These findings indicate that protease 2A–mediated cleavage of dystrophin is critical for viral propagation, enteroviral-mediated cytopathic effects, and the development of cardiomyopathy.
Byung-Kwan Lim, Angela K. Peter, Dingding Xiong, Anna Narezkina, Aaron Yung, Nancy D. Dalton, Kyung-Kuk Hwang, Toshitaka Yajima, Ju Chen, Kirk U. Knowlton
Angiotensin converting enzyme 2 (ACE2) is a negative regulator of the renin-angiotensin system (RAS), catalyzing the conversion of Angiotensin II to Angiotensin 1-7. Apelin is a second catalytic substrate for ACE2 and functions as an inotropic and cardioprotective peptide. While an antagonistic relationship between the RAS and apelin has been proposed, such functional interplay remains elusive. Here we found that ACE2 was downregulated in apelin-deficient mice. Pharmacological or genetic inhibition of angiotensin II type 1 receptor (AT1R) rescued the impaired contractility and hypertrophy of apelin mutant mice, which was accompanied by restored ACE2 levels. Importantly, treatment with angiotensin 1-7 rescued hypertrophy and heart dysfunctions of apelin-knockout mice. Moreover, apelin, via activation of its receptor, APJ, increased ACE2 promoter activity in vitro and upregulated ACE2 expression in failing hearts in vivo. Apelin treatment also increased cardiac contractility and ACE2 levels in AT1R-deficient mice. These data demonstrate that ACE2 couples the RAS to the apelin system, adding a conceptual framework for the apelin-ACE2–angiotensin 1-7 axis as a therapeutic target for cardiovascular diseases.
Teruki Sato, Takashi Suzuki, Hiroyuki Watanabe, Ayumi Kadowaki, Akiyoshi Fukamizu, Peter P. Liu, Akinori Kimura, Hiroshi Ito, Josef M. Penninger, Yumiko Imai, Keiji Kuba
Basal autophagy is a crucial mechanism in cellular homeostasis, underlying both normal cellular recycling and the clearance of damaged or misfolded proteins, organelles and aggregates. We showed here that enhanced levels of autophagy induced by either autophagic gene overexpression or voluntary exercise ameliorated desmin-related cardiomyopathy (DRC). To increase levels of basal autophagy, we generated an inducible Tg mouse expressing autophagy-related 7 (
Md. Shenuarin Bhuiyan, J. Scott Pattison, Hanna Osinska, Jeanne James, James Gulick, Patrick M. McLendon, Joseph A. Hill, Junichi Sadoshima, Jeffrey Robbins
The induction of autophagy in the mammalian heart during the perinatal period is an essential adaptation required to survive early neonatal starvation; however, the mechanisms that mediate autophagy suppression once feeding is established are not known. Insulin signaling in the heart is transduced via insulin and IGF-1 receptors (IGF-1Rs). We disrupted insulin and IGF-1R signaling by generating mice with combined cardiomyocyte-specific deletion of
Christian Riehle, Adam R. Wende, Sandra Sena, Karla Maria Pires, Renata Oliveira Pereira, Yi Zhu, Heiko Bugger, Deborah Frank, Jack Bevins, Dong Chen, Cynthia N. Perry, Xiaocheng C. Dong, Steven Valdez, Monika Rech, Xiaoming Sheng, Bart C. Weimer, Roberta A. Gottlieb, Morris F. White, E. Dale Abel
Ischemic damage is recognized to cause cardiomyocyte (CM) death and myocardial dysfunction, but the role of cell-matrix interactions and integrins in this process has not been extensively studied. Expression of α7β1D integrin, the dominant integrin in normal adult CMs, increases during ischemia/reperfusion (I/R), while deficiency of β1 integrins increases ischemic damage. We hypothesized that the forced overexpression of integrins on the CM would offer protection from I/R injury. Tg mice with CM-specific overexpression of integrin α7β1D exposed to I/R had a substantial reduction in infarct size compared with that of α5β1D-overexpressing mice and WT littermate controls. Using isolated CMs, we found that α7β1D preserved mitochondrial membrane potential during hypoxia/reoxygenation (H/R) injury via inhibition of mitochondrial Ca2+ overload but did not alter H/R effects on oxidative stress. Therefore, we assessed Ca2+ handling proteins in the CM and found that β1D integrin colocalized with ryanodine receptor 2 (RyR2) in CM T-tubules, complexed with RyR2 in human and rat heart, and specifically bound to RyR2 amino acids 165–175. Integrins stabilized the RyR2 interdomain interaction, and this stabilization required integrin receptor binding to its ECM ligand. These data suggest that α7β1D integrin modifies Ca2+ regulatory pathways and offers a means to protect the myocardium from ischemic injury.
Hideshi Okada, N. Chin Lai, Yoshitaka Kawaraguchi, Peter Liao, Jeffrey Copps, Yasuo Sugano, Sunaho Okada-Maeda, Indroneal Banerjee, Jan M. Schilling, Alexandre R. Gingras, Elizabeth K. Asfaw, Jorge Suarez, Seok-Min Kang, Guy A. Perkins, Carol G. Au, Sharon Israeli-Rosenberg, Ana Maria Manso, Zheng Liu, Derek J. Milner, Stephen J. Kaufman, Hemal H. Patel, David M. Roth, H. Kirk Hammond, Susan S. Taylor, Wolfgang H. Dillmann, Joshua I. Goldhaber, Robert S. Ross
P311 is an 8-kDa intracellular protein that is highly conserved across species and is expressed in the nervous system as well as in vascular and visceral smooth muscle cells.
Kameswara Rao Badri, Ming Yue, Oscar A. Carretero, Sree Latha Aramgam, Jun Cao, Stephen Sharkady, Gene H. Kim, Gregory A. Taylor, Kenneth L. Byron, Lucia Schuger
Myeloperoxidase (MPO) and paraoxonase 1 (PON1) are high-density lipoprotein–associated (HDL-associated) proteins mechanistically linked to inflammation, oxidant stress, and atherosclerosis. MPO is a source of ROS during inflammation and can oxidize apolipoprotein A1 (APOA1) of HDL, impairing its atheroprotective functions. In contrast, PON1 fosters systemic antioxidant effects and promotes some of the atheroprotective properties attributed to HDL. Here, we demonstrate that MPO, PON1, and HDL bind to one another, forming a ternary complex, wherein PON1 partially inhibits MPO activity, while MPO inactivates PON1. MPO oxidizes PON1 on tyrosine 71 (Tyr71), a modified residue found in human atheroma that is critical for HDL binding and PON1 function. Acute inflammation model studies with transgenic and knockout mice for either PON1 or MPO confirmed that MPO and PON1 reciprocally modulate each other’s function in vivo. Further structure and function studies identified critical contact sites between APOA1 within HDL, PON1, and MPO, and proteomics studies of HDL recovered from acute coronary syndrome (ACS) subjects revealed enhanced chlorotyrosine content, site-specific PON1 methionine oxidation, and reduced PON1 activity. HDL thus serves as a scaffold upon which MPO and PON1 interact during inflammation, whereupon PON1 binding partially inhibits MPO activity, and MPO promotes site-specific oxidative modification and impairment of PON1 and APOA1 function.
Ying Huang, Zhiping Wu, Meliana Riwanto, Shengqiang Gao, Bruce S. Levison, Xiaodong Gu, Xiaoming Fu, Matthew A. Wagner, Christian Besler, Gary Gerstenecker, Renliang Zhang, Xin-Min Li, Anthony J. DiDonato, Valentin Gogonea, W.H. Wilson Tang, Jonathan D. Smith, Edward F. Plow, Paul L. Fox, Diana M. Shih, Aldons J. Lusis, Edward A. Fisher, Joseph A. DiDonato, Ulf Landmesser, Stanley L. Hazen
Protein quality control and metabolic homeostasis are integral to maintaining cardiac function during stress; however, little is known about if or how these systems interact. Here we demonstrate that C terminus of HSC70-interacting protein (CHIP), a regulator of protein quality control, influences the metabolic response to pressure overload by direct regulation of the catalytic α subunit of AMPK. Induction of cardiac pressure overload in
Jonathan C. Schisler, Carrie E. Rubel, Chunlian Zhang, Pamela Lockyer, Douglas M. Cyr, Cam Patterson
Numerous common genetic variants have been linked to blood pressure, but no underlying mechanism has been elucidated. Population studies have revealed that the variant rs5068 (A/G) in the 3′ untranslated region of
Pankaj Arora, Connie Wu, Abigail May Khan, Donald B. Bloch, Brandi N. Davis-Dusenbery, Anahita Ghorbani, Ester Spagnolli, Andrew Martinez, Allicia Ryan, Laurel T. Tainsh, Samuel Kim, Jian Rong, Tianxiao Huan, Jane E. Freedman, Daniel Levy, Karen K. Miller, Akiko Hata, Federica del Monte, Sara Vandenwijngaert, Melissa Swinnen, Stefan Janssens, Tara M. Holmes, Emmanuel S. Buys, Kenneth D. Bloch, Christopher Newton-Cheh, Thomas J. Wang
The heparan sulfate proteoglycan (HSPG) syndecan-1 (SDC1) acts as a major receptor for triglyceride-rich lipoprotein (TRL) clearance in the liver. We sought to identify the relevant apolipoproteins on TRLs that mediate binding to SDC1 and determine their clinical relevance. Evidence supporting ApoE as a major determinant arose from its enrichment in TRLs from mice defective in hepatic heparan sulfate (
Jon C. Gonzales, Philip L.S.M. Gordts, Erin M. Foley, Jeffrey D. Esko
Peripartum cardiomyopathy (PPCM) is a life-threatening pregnancy-associated cardiomyopathy in previously healthy women. Although PPCM is driven in part by the 16-kDa N-terminal prolactin fragment (16K PRL), the underlying molecular mechanisms are poorly understood. We found that 16K PRL induced microRNA-146a (miR-146a) expression in ECs, which attenuated angiogenesis through downregulation of
Julie Halkein, Sebastien P. Tabruyn, Melanie Ricke-Hoch, Arash Haghikia, Ngoc-Quynh-Nhu Nguyen, Michaela Scherr, Karolien Castermans, Ludovic Malvaux, Vincent Lambert, Marc Thiry, Karen Sliwa, Agnes Noel, Joseph. A. Martial, Denise Hilfiker-Kleiner, Ingrid Struman
Ping Ye, Wenhao Chen, Jie Wu, Xiaofan Huang, Jun Li, Sihua Wang, Zheng Liu, Guohua Wang, Xiao Yang, Peng Zhang, Qiulun Lv, Jiahong Xia
Atrial fibrillation (AF) is a highly prevalent arrhythmia with pronounced morbidity and mortality. Inward-rectifier K+ current (
Xiaobin Luo, Zhenwei Pan, Hongli Shan, Jiening Xiao, Xuelin Sun, Ning Wang, Huixian Lin, Ling Xiao, Ange Maguy, Xiao-Yan Qi, Yue Li, Xu Gao, Deli Dong, Yong Zhang, Yunlong Bai, Jing Ai, Lihua Sun, Hang Lu, Xiao-Yan Luo, Zhiguo Wang, Yanjie Lu, Baofeng Yang, Stanley Nattel
Reverse cholesterol transport (RCT) refers to the mobilization of cholesterol on HDL particles (HDL-C) from extravascular tissues to plasma, ultimately for fecal excretion. Little is known about how HDL-C leaves peripheral tissues to reach plasma. We first used 2 models of disrupted lymphatic drainage from skin — 1 surgical and the other genetic — to quantitatively track RCT following injection of [3H]-cholesterol–loaded macrophages upstream of blocked or absent lymphatic vessels. Macrophage RCT was markedly impaired in both models, even at sites with a leaky vasculature. Inhibited RCT was downstream of cholesterol efflux from macrophages, since macrophage efflux of a fluorescent cholesterol analog (BODIPY-cholesterol) was not altered by impaired lymphatic drainage. We next addressed whether RCT was mediated by lymphatic vessels from the aortic wall by loading the aortae of donor atherosclerotic
Catherine Martel, Wenjun Li, Brian Fulp, Andrew M. Platt, Emmanuel L. Gautier, Marit Westerterp, Robert Bittman, Alan R. Tall, Shu-Hsia Chen, Michael J. Thomas, Daniel Kreisel, Melody A. Swartz, Mary G. Sorci-Thomas, Gwendalyn J. Randolph