Abstract
Pseudoxanthoma Elasticum (PXE) is a rare disease caused by loss of function of the gene Abcc6 and characterized by ectopic calcification of multiple tissues, but the physiological reasons underlying ectopic calcification in PXE remain unclear. In a murine model of Abcc6 deficient PXE where animals develop robust cardiac calcification after heart injury, we show the critical importance of the liver in mediating ectopic cardiac calcification. Tissue-specific deletion of Abcc6 in the liver, but not in the heart was sufficient to cause post-injury cardiac calcification. Metabolomics and gene expression demonstrated deficiencies in nucleotide metabolism, cellular energetics and defects in cellular respiration, underlying ectopic calcification in PXE. Functional abnormalities in cellular respiration in the injured heart were similar in globally or liver-specific Abcc6-deficient animals demonstrating that hepatic Abcc6 expression regulates cellular respiration in the injured heart. We show that ectopic calcification in PXE is primarily dystrophic and treatment with clodronate or etidronate, that prevent the growth of calcium hydroxyapatite mineralization, was sufficient to rescue the phenotype of ectopic cardiac calcification in Abcc6-deficient states. Taken together, these observations highlight the role of the liver in regulating target tissue metabolic and mitochondrial function in causing ectopic calcification in Abcc6-deficient states.
Authors
Yijie Wang, Baiming Sun, Feiyang Ma, Bo Tao, Yiqian Gu, Zhiqiang Zhou, Jason Kim, Linlin Zhang, Zhihao Liu, Johanna ten Hoeve, Linsey Stiles, Lucia Fernandez-del-Rio, Calvin Pan, Orian Shirihai, Shili Xu, Thomas G. Graeber, Tamer Sallam, Matteo Pellegrini, Aldons J. Lusis, Arjun Deb
Abstract
Aortic aneurysms are age-linked aortic dilations that progress silently and carry high rupture mortality. Immune cells are recognized drivers of aneurysm pathogenesis. Clonal hematopoiesis is an age-related expansion of somatically mutated hematopoietic stem cells that reshapes immune function and contributes to diverse age-associated diseases. However, its contribution to aneurysm pathogenesis remains unclear. In this study, targeted ultradeep sequencing of patient specimens revealed a high prevalence of clonal hematopoiesis-associated mutations that correlated with faster aneurysm expansion. Thus, we modeled clonal hematopoiesis by competitively transplanting Tet2-deficient bone marrow into ApoE-knockout mice and induced aneurysms with angiotensin II. Tet2-clonal hematopoiesis mice developed significantly greater aortic dilation than controls. Interestingly, Tet2-deficient macrophages adopted an ACP5-positive, osteoclast-like state and produced more MMP9. Both genetic and pharmacological inhibition of osteoclast-like differentiation suppressed the Tet2-mediated aneurysmal growth in vivo. Thus, Tet2-driven clonal hematopoiesis accelerates aortic aneurysm progression through MMP9-producing osteoclast-like macrophages and therefore represents a tractable therapeutic axis.
Authors
Jun Yonekawa, Yoshimitsu Yura, Junmiao Luo, Katsuhiro Kato, Shuta Ikeda, Yohei Kawai, Tomoki Hattori, Ryotaro Okamoto, Mari Kizuki, Emiri Miura-Yura, Keita Horitani, Kyung-Duk Min, Takuo Emoto, Hiroshi Banno, Mikito Takefuji, Kenneth Walsh, Toyoaki Murohara
Abstract
Stereotactic arrhythmia radiotherapy (STAR) is emerging as a highly effective treatment for ventricular tachycardia (VT). Growing evidence indicates that STAR favorably reprograms the electrical substrate by speeding conduction and/or prolonging repolarization via modulating ion channel expression, though the mechanisms whereby single-fraction radiation mediates durable changes in gene expression are incompletely understood. Here, we identify dynamic changes in the cardiomyocyte epigenome and transcriptome after irradiation (IR) in vivo and in vitro, including durably increased expression and chromatin accessibility of Scn5a (encoding the alpha subunit of the sodium channel, NaV1.5), demonstrating a role for epigenetic memory in conduction velocity (CV) increases observed after STAR. Transcriptomic and epigenetic sequencing further identify dynamic changes to gene expression and regulatory regions involved in cellular repolarization, calcium handling, and metabolism after IR. These changes are mirrored by dose-dependent and cell-autonomous changes in repolarization, calcium flux, and mitochondrial respiration, highlighting important cellular processes which may mediate therapeutic effects of STAR. Overall, we find that cardiomyocytes exposed to a single fraction of high-dose IR exhibit epigenetic reprogramming that mediates broad and dynamic physiologic responses.
Authors
Samuel D. Jordan, Shuhua Fu, Abigail Fulkerson, Donghua Hu, Sherwin Ng, David M. Zhang, Sneha Manikandan, Jeffrey Szymanski, Nan Hu, Yuqian Xie, Anish Bedi, James J. Tabor, Lauren Boggs-Bailey, Lori Strong, Stephanie Hicks, Lavanya Aryan, Nishanth Gabriel, Geoffrey D. Hugo, Kuo-Chan Weng, Nathaniel Huebsch, Julie K. Schwarz, Bo Zhang, Stacey L. Rentschler
Abstract
Obesity is accompanied by increases in free fatty acids (FFAs) in the systemic circulation, and obese patients often develop cardiac hypertrophy and diastolic dysfunction, termed obesity cardiomyopathy. Proinflammatory cytokines, including IL-6, have been implicated in the pathogenesis of the cardiac dysfunction associated with obesity cardiomyopathy. Elevation of FFAs induced by high fat diet (HFD) consumption induced diastolic dysfunction in the heart as early as after one month. HFD consumption directly stimulated IL-6 production in cardiomyocytes before local inflammation developed and induced diastolic dysfunction even in the presence of macrophage depletion with clodronate in the heart. PPARα played an essential role in mediating Il6 transcription in response to HFD consumption by forming a heterodimer with p50/RelA and binding to the NFκB element in cardiomyocytes. Local production of IL-6 in cardiomyocytes, in turn, mediated the development of diastolic cardiac dysfunction. HFD-induced diastolic dysfunction was attenuated by cardiac-specific deletion of either Ppara or Il6, as well as by interference with the PPARα-NFκB heterodimer formation by a molecular decoy. These results suggest that elevated FFAs directly upregulate Il6 through the PPARα-NFκB heterodimer in cardiomyocytes and highlight autocrine production of IL-6 as a key downstream mechanism in the initial development of diastolic dysfunction.
Authors
Shin-ichi Oka, Eun-Ah Sung, Peiyong Zhai, Kevin B. Schesing, Santosh Bhat, Adave Chin, Jiyeon Park, Yeun-Jun Chung, Akihiro Shirakabe, Takanobu Yamamoto, Yoshiyuki Ikeda, Wataru Mizushima, Shohei Ikeda, Mingming Tong, Jaemin Byun, Michinari Nakamura, Samuel I. Kim, Jamie Francisco, Dominic P. Del Re, Junichi Sadoshima
Abstract
Human genetic studies have repeatedly associated ADAMTS7 with atherosclerotic cardiovascular disease. Subsequent investigations in mice demonstrated that ADAMTS7 is proatherogenic and induced in response to vascular injury. However, the cell-specific mechanisms governing ADAMTS7 proatherogenicity remain unclear. To determine which vascular cell types express ADAMTS7, we interrogated single-cell RNA sequencing of human carotid atherosclerosis and found ADAMTS7 expression in smooth muscle cells (SMCs), endothelial cells (ECs), and fibroblasts. We subsequently created SMC- and EC-specific Adamts7 conditional knockout and transgenic mice. Conditional knockout of Adamts7 in either cell type does not reduce atherosclerosis, whereas transgenic induction in either cell type increases atherosclerosis. In SMC transgenic mice, this increase coincides with an expansion of lipid-laden SMC foam cells and a decrease in fibrous cap formation. RNA-sequencing in Adamts7 overexpressing SMCs revealed an upregulation of lipid genes typically assigned to macrophages. Mechanistically, ADAMTS7 increases SMC oxLDL uptake through CD36, whose expression is upregulated by PU.1. ATAC-seq and motif analysis revealed increased chromatin accessibility at AP-1 enriched regions, consistent with AP-1 dependent remodeling of PU.1-regulated lipid-handling loci. In summary, ADAMTS7 promotes atherosclerosis by driving SMC foam cell formation through an AP-1/PU.1/CD36 regulatory axis.
Authors
Allen Chung, Lauren E. Fries, Hyun-Kyung Chang, Huize Pan, Alexander C. Bashore, Karissa Shuck, Caio V. Matias, Juliana Gomez Pardo, Jordan S. Kesner, Hanying Yan, Mingyao Li, Robert C. Bauer
Abstract
Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of death worldwide, with plaque instability being a major culprit. Phenotypic switching of vascular smooth muscle cells (VSMCs) is a central event in atherosclerosis, driving both plaque progression and stability, yet the underlying mechanisms are incompletely understood, limiting drug development targeting this process. Kinesin family member 13B (KIF13B) has been implicated in vascular biology, but its function in VSMCs is unknown. Here, we demonstrate that VSMC-specific deletion of Kif13b in mice overexpressing proprotein convertase subtilisin/kexin type 9 (PCSK9) exacerbates lesion development and impairs plaque stability, characterized by thinner fibrous caps and increased inflammation. Mechanistically, we identified that KIF13B facilitates the ubiquitination and proteasomal degradation of Krüppel-like factor 4 (KLF4) through the Potassium channel tetramerization domain containing 10 (KCTD10)-dependent pathway. This KIF13B/KCTD10 axis reduces KLF4 protein levels, thereby inhibiting the pro-inflammatory responses and fibroblast-like transition of VSMCs to preserve their contractile phenotype. Importantly, the adverse effects of Kif13b deficiency on atherogenesis were effectively rescued by the small-molecule KLF4 inhibitor Kenpaullone. Our results unveil a VSMC-specific atheroprotective role for KIF13B, define the KIF13B/KCTD10/KLF4 pathway as a key regulatory axis governing VSMC fate and plaque stability, and validate its therapeutic potential for treating advanced atherosclerosis.
Authors
Guolin Miao, Yufei Han, Jingxuan Chen, Yiran Liu, Ge Zhang, Shaotong Pei, Yinqi Zhao, Yitong Xu, Liwen Zheng, Zhaoling Li, Xiangru Liu, Sijing Shi, Xuya Kang, Yahan Liu, Ling Zhang, Wei Huang, Yuhui Wang, Junnan Tang, Erdan Dong, Xunde Xian
Abstract
How β-Catenin (βCat) mediates tissue hyperplasia is poorly understood. To explore this, we employed the adrenal cortex as a model system given its stereotypical spatial organization and the important role βCat plays in homeostasis and disease. For example, excessive production of aldosterone by the adrenal cortex (primary aldosteronism, PA) constitutes a major cause of cardiovascular morbidity and is associated with βCat gain-of-function (βCat-GOF). Adherens junctions (AJs) connect the actin cytoskeletons of adjacent zona Glomerulosa (zG) cells via a cadherin-βCat-α-Catenin complex and mediate aldosterone production. Whether βCat-GOF drives zG hyperplasia, a key feature of PA, via AJs is unknown. Here, we showed that aldosterone secretagogues (K+, AngII) and βCat-GOF mediated AJ formation via Rho/ROCK/actomyosin signaling. In addition, Rho/ROCK inhibition led to altered zG rosette morphology and decreased aldosterone production. Mice with zG-specific βCat-GOF demonstrated increased AJ formation and zG hyperplasia, which was blunted by Rho/ROCK inhibition and deletion of α-Catenin. βCat also impacted AJ formation independently of its role as a transcription factor. Furthermore, analysis of human aldosterone-producing adenomas revealed high levels of βCat expression were associated with increased membranous expression of K-Cadherin. Together, our findings identified Rho/ROCK signaling and αCat as key mediators of AJ formation and βCat-driven hyperplasia.
Authors
Mesut Berber, Betul Haykir, Nick A. Guagliardo, Vasileios Chortis, Kleiton Silva Borges, Paula Q. Barrett, Felix Beuschlein, Diana L. Carlone, David T. Breault
Abstract
The urokinase plasminogen activator receptor (uPAR) is a membrane-bound protein found on the surface of immune cells. Through the action of proteases, uPAR is cleaved to produce several circulating proteins in the bloodstream, including the soluble form suPAR and the fragments D1 and D2D3. Initially studied in the context of infectious diseases and cancer, recent research has revealed roles for suPAR and its related proteins as mediators linking innate immunity to the pathogenesis of kidney and cardiovascular diseases, as well as insulin-dependent diabetes. While these proteins have long been recognized as prognostic biomarkers, growing clinical, experimental, and genetic evidence highlights their active involvement in the onset and progression of these diverse conditions. This Review examines suPAR’s evolution from its discovery as a modulator of innate immunity to its current status as a key driver in chronic kidney and cardiovascular diseases. Furthermore, we explore the molecular mechanisms through which suPAR and D2D3 contribute to multiorgan damage, emphasizing emerging opportunities for therapeutic interventions across interconnected organ systems.
Authors
Jochen Reiser, Salim S. Hayek, Sanja Sever
Abstract
Authors
Alexander M. Loiben, Wei-Ming Chien, Ashley McKinstry, Dania Ahmed, Matthew C. Childers, Michael Regnier, Charles E. Murry, Kai-Chun Yang
Abstract
BACKGROUND. Cardiac allograft vasculopathy (CAV) is consistently accompanied by immune infiltrates surrounding affected coronary arteries, including antibody-producing plasma cells (PC). The antigenic drivers of these intragraft PC responses remain poorly defined. METHODS. We characterized graft-infiltrating PC by single-cell RNA sequencing and immunoglobulin gene profiling. Using immunoglobulin sequences we generated 37 recombinant monoclonal antibodies (mAb) from dominant intragraft PC clones and 24 control mAb from peripheral blood PC. Antigen reactivity was screened against chemical adducts, including bilirubin, a heme-degradation by-product. Histologic and tissue analyses assessed bilirubin deposition as well as expression of heme-catabolic enzymes, and the presence of Fe2+ in heart explants with CAV. RESULTS. A majority of graft-derived mAb (21/37; ~57%) but none of the mAb derived from blood PC reacted to bilirubin. Bilirubin deposition was detected within lymphocytic aggregates in CAV grafts. In coronary arteries with CAV lesions, bilirubin accumulated in the cytoplasm and nuclei of smooth muscle cells in the tunica media, a pattern not observed in healthy heart tissue. Lastly, we detected the expression of heme-oxygenase-1 and biliverdin reductases in graft-infiltrating macrophages along with the presence of Fe2+ ion in the media of arteries with hyperplasia. CONCLUSION. These findings suggest that local heme catabolism and resultant bilirubin accumulation create a prominent target for intragraft antibody responses in CAV. Bilirubin-specific antibodies and heme-catabolic pathways may contribute to CAV pathogenesis and represent potential mechanistic and therapeutic avenues for further investigation. FUNDING. National Institute of Health.
Authors
Sarah B. See, Talita Aguiar, Max Dietzel, Mattea Ausmeier, Hang T.T. Nguyen, Shunya Mashiko, Laura Donadeu, Hector Cordero, Poulomi Roy, Lorea Roson, Charles C. Marboe, Matthias J. Szabolcs, Maryjane Farr, Jose González-Costello, Aleix Olivella, Yoshifumi Naka, Koji Takeda, Rodica Vasilescu, Kevin J. Clerkin, Gilles Benichou, Joren C. Madsen, R. Glenn King, Oriol Bestard, Evan P. Kransdorf, Emmanuel Zorn
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)