Abstract
Authors
Rong Tian, E. Douglas Lewandowski
Abstract
Authors
Chai-Wan Kim, Matthew A. Mitsche, Jay D. Horton
Abstract
Authors
Diwakar Turaga, Chang-Ru Tsai, Yuka Morikawa, Hanna J. Tadros, Yi Zhao, Lalita Wadhwa, Iki Adachi, Xiao Li, James F. Martin
Abstract
Authors
Diana B. Voss, Emily J. Shields, Andrey Poleshko, Li Li, Jun Li, Roger Wang, Mariacristina Calcagno, Rajan Jain, Cheryl L. Smith, Jonathan A. Epstein
Abstract
Authors
Seyi E. Elasoru, Christian Miccile, Jingwu Pan, Zhaoyang Zhang, Kalyanam Shivkumar, Herbert Herzog, Robert D. Harvey, Zhilin Qu, Olujimi A. Ajijola
Abstract
The endocardium is a major source of coronary angiogenesis and arterialization, through coordinated cell fate transition and migration. However, the transcriptional regulatory network synchronizing cell fate determination and movement remains unclear. Here, we identified transcription factor HAND2 as a key candidate for coronary vascular formation. Endocardial deletion of Hand2 in mice disrupted arterial-venous networks and stunted coronary arteries, paralleling a ventricular noncompaction phenotype. Moreover, deletion of Hand2 produced excessive tip cells with defective movement. RNA-seq analysis revealed enhanced hypoxic metabolic activation but declined TGF-β/p38MAPK-dependent endothelial-to-mesenchymal transition (Endo-MT). In consistence, genetic inhibition of the core hypoxic regulators or pharmaceutical administration of TGFβ2 partially recovered the coronary arterial defects in Hand2 mutants. Furthermore, HAND2 was found directly bound to promoters of the target genes, harmonizing cell migration and cell fate transition. These findings pinpoint HAND2 as an essential regulator of the endocardial transcriptional regulatory network for coronary arterialization and provide potential therapeutic targets for coronary artery diseases.
Authors
Huijuan Wang, Haosheng Zhang, Leiyin Zheng, Peihan Zhang, Yuqian Wang, Sijia Ding, Wenping Liu, Yuanming Cheng, Zhongzhou Yang, Wen Luo
Abstract
Myofibroblasts are the cells responsible for collagen production, leading to tissue fibrosis. Because 20.5% of the total amino acids in collagen are proline, myofibroblasts must acquire a well-developed proline-producing mechanism during their differentiation. However, the detailed mechanism for myofibroblasts to acquire and keep the developed proline biosynthesis machinery remains obscure. Here, we show branched-chain amino acid transaminase 1 (Bcat1) is up-regulated in a substantial subset of Postn-expressing proto-myofibroblast-like fibroblasts, transitional cells en route to fully differentiated myofibroblasts, as well as in myofibroblasts in the fibrotic heart and liver of mice and humans and promotes the proline production. The branched-chain amino acid (BCAA) production by BCAT1 promotes SMAD3 phosphorylation via HDAC5 phosphorylation at Ser488, thereby enhancing SMAD3-dependent transcription of proline biosynthesis-related genes, Aldh18a1, Pycr1, and Eprs, in proto-myofibroblast-like fibroblasts and myofibroblasts. In BCAT1-deficient mice, expression of proline biosynthesis-related genes is significantly attenuated in their hearts after myocardial infarction, resulting in decreased cardiac fibrosis. Moreover, BCAT1 inhibitor treatment of mice with myocardial infarction reduces cardiac fibrosis. Our results identified a BCAT1-mediated pathway that promotes collagen production via proline biosynthesis regulation in proto-myofibroblast-like fibroblasts and myofibroblasts, which may provide a therapeutic target for cardiac fibrosis.
Authors
Noburo Takizawa, Takanori Hironaka, Hayato Watanabe, Haruna Suetsugu, Keisuke Yoshioka, Yuma Horii, Yuri Nagata, Hiroaki Matoba, Hidetaka Kosako, Kenji Hamase, Go Hirai, Michio Nakaya
Abstract
Gut microbiota-derived trimethylamine N-oxide (TMAO) plays a role in the pathogenesis of cardiovascular disease. The role of TMAO in the pathogenesis of atrial fibrillation (AF) remains uncertain. TMAO levels were quantified in plasma from serial subjects undergoing elective cardiac catheterizations (N=5090) and shown to independently associate with prevalent AF following adjustment for risk factors (TMAO adjusted odds ratio 1.7 [95% confidence interval 1.3-2.1]; P<0.01). Human cAMP response element modulator isoform IbΔC-X transgenic mice (CREM-IbΔC-X), a spontaneous mouse model of AF, supplemented with a TMAO diet developed AF sooner. C57BL/6J mice on and off a TMAO had more inducible AF via a transesophageal pacing study compared to chow controls. Dietary choline supplementation increased circulating TMAO levels and significantly accelerated AF onset in CREM-IbΔC-X mice (P<0.01). Iodomethylcholine (IMC), the gut microbial CutC/D inhibitor that suppresses choline→TMA(O) metabolic transformation, reduced circulating TMAO levels (P<0.0001) and choline induced AF onset (P<0.01). Cecal metagenomic analyses showed that choline supplementation induced changes in microbial communities associated with AF, while many of these changes were attenuated by IMC. Choline supplementation promoted overall adverse atrial remodeling with left atrial dilation. Optical mapping studies showed that mice supplemented with choline exhibited reduced conduction velocity, shortened action potential duration at 80% repolarization, and decreased wavelength. TMAO inhibits muscarinic receptor 2 resulting in autonomic dysfunction that promotes AF. In summary, the gut microbial metabolite TMAO, independently associated with AF risk in subjects, enhances AF in multiple AF mouse models via autonomic dysfunction, and is a therapeutic target for prevention of AF.
Authors
Selvam Arjunan, Isaiah Pemberton, Xinmin S. Li, Naseer Sangwan, Lydia Akino, Emmanuel Opoku, Dmitriy Verbovetskiy, Ina Nemet, Hyun Su Kim, Haruko Masumiya, Zeneng Wang, Joseph A. Lupica, Melissa Y. Tian, Karis Mao, Deepthi P. Mallela, Maradumane Mohan, Sarah Schumacher, Julie H. Rennison, Sathyamangla Prasad, Kenneth R. Laurita, Vamsi Chodisetty, Mina K. Chung, David R. Van Wagoner, John Barnard, Jonathan D. Smith, Oussama Wazni, Stanley L. Hazen, Robert A. Koeth
Abstract
Inflammation contributes to the pathogenesis of myocardial infarction and heart failure and represents a viable therapeutic target. Monocytes and their progeny are highly abundant and display striking functional diversity, serving as key determinants of myocardial inflammation and tissue repair. Much remains to be learned regarding mechanisms and signaling events that instruct monocyte fate decisions. We devised a genetic lineage tracing strategy using Ccr2crERT2Rosa26LSL-tdTomato mice in combination with single cell RNA-sequencing to map the differentiation trajectories of monocytes that infiltrate the heart after reperfused myocardial infarction. Monocytes were recruited to the heart early after injury and gave rise to transcriptionally distinct and spatially restricted macrophage and dendritic cell-like subsets that were specified prior to extravasation and chronically persisted within the myocardium. Pseudotime analysis predicted two differentiation trajectories of monocyte-derived macrophages that are partitioned into the border and infarct zones, respectively. Among these trajectories, we demonstrated that macrophages expressing a type I interferon responsive signature were an intermediate population that gave rise to MHC-IIhi macrophages, were localized within the border zone, induce regulatory T cells, and promote myocardial protection. Collectively, these data uncover complexities of monocyte differentiation in the infarcted heart and suggest that modulating monocyte fate decisions may have clinical implications.
Authors
Andrew L. Koenig, Farid F. Kadyrov, Junedh M. Amrute, Steven Yang, Carla J. Weinheimer, Jessica M. Nigro, Attila Kovacs, Wenjun Li, Gabriella B. Smith, Lance Yeh, Daniel Kreisel, Kory J. Lavine
Abstract
Gene therapy-based biological pacemakers have been proposed as an alternative to their hardware-based counterparts. In this context, short-term ectopic expression of the T-box transcription factor 18 (TBX18) in the ventricle has been reported to generate potent short-term pacemaker function in various animal models. Here, we investigated the impact of adeno-associated virus (AAV)-mediated long-term expression of TBX18, and compared the outcomes to those of the pacemaker ion channel Hcn2. Our findings revealed that CMV-driven ectopic TBX18 expression in mouse hearts led to severe cardiac fibrosis. At lower, non-fibrogenic levels, TBX18 maintained its transcriptional function but failed to induce pacemaker phenotypes. TBX18-expressing cells showed suppressed expression of key working myocardial genes, but the pacemaker gene program was not induced. Electrophysiological studies showed abnormal automaticity in TBX18-expressing cells, combined with prolonged repolarization and various current changes. However, no hyperpolarization-activated funny current was detected. In a complete AV-block rat model, AAV-mediated Hcn2 expression induced robust ectopic pacemaker activity in the presence of isoproterenol, whereas TBX18 expression neither generated such activity nor augmented Hcn2-mediated pacing. In conclusion, at functionally non-fibrogenic levels, TBX18 is neither sufficient nor necessary to induce pacemaker activity. In contrast, Hcn2 generates reliable pacing, making it a more viable candidate for biological pacemaker development.
Authors
Jianan Wang, Mathilde R. Rivaud, Mischa Klerk, Arie R. Boender, Ruud N. Visser, Rinske Sparrius, Hee Young Lee, Karel van Duijvenboden, Huiling Zhou, Yuting Yang, Emiel J.M. Kramer, Kyung Ho Park, Larry C. Park, Silke Schrödel, Christian Thirion, Eric Ehrke-Schulz, Anja Ehrhardt, Osne F. Kirzner, Klaus Neef, Hanno L. Tan, Arie O. Verkerk, Vincent M. Christoffels, Gerard J.J. Boink
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ISSN: 0021-9738 (print), 1558-8238 (online)