Browsing by Author "Zhang, Lu"

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    Arrhythmia Mechanism and Dynamics in a Humanized Mouse Model of Inherited Cardiomyopathy Caused by Phospholamban R14del Mutation
    (American Heart Association, 2021) Raad, Nour; Bittihn, Philip; Cacheux, Marine; Jeong, Dongtak; Ilkan, Zeki; Ceholski, Delaine; Kohlbrenner, Erik; Zhang, Lu; Cai, Chen-Leng; Kranias, Evangelia G.; Hajjar, Roger J.; Stillitano, Francesca; Akar, Fadi G.; Pediatrics, School of Medicine
    Background: Arginine (Arg) 14 deletion (R14del) in the calcium regulatory protein phospholamban (hPLNR14del) has been identified as a disease-causing mutation in patients with an inherited cardiomyopathy. Mechanisms underlying the early arrhythmogenic phenotype that predisposes carriers of this mutation to sudden death with no apparent structural remodeling remain unclear. Methods: To address this, we performed high spatiotemporal resolution optical mapping of intact hearts from adult knock-in mice harboring the human PLNWT (wildtype [WT], n=12) or the heterozygous human PLNR14del mutation (R14del, n=12) before and after ex vivo challenge with isoproterenol and rapid pacing. Results: Adverse electrophysiological remodeling was evident in the absence of significant structural or hemodynamic changes. R14del hearts exhibited increased arrhythmia susceptibility compared with wildtype. Underlying this susceptibility was preferential right ventricular action potential prolongation that was unresponsive to β-adrenergic stimulation. A steep repolarization gradient at the left ventricular/right ventricular interface provided the substrate for interventricular activation delays and ultimately local conduction block during rapid pacing. This was followed by the initiation of macroreentrant circuits supporting the onset of ventricular tachycardia. Once sustained, these circuits evolved into high-frequency rotors, which in their majority were pinned to the right ventricle. These rotors exhibited unique spatiotemporal dynamics that promoted their increased stability in R14del compared with wildtype hearts. Conclusions: Our findings highlight the crucial role of primary electric remodeling caused by the hPLNR14del mutation. These inherently arrhythmogenic features form the substrate for adrenergic-mediated VT at early stages of PLNR14del induced cardiomyopathy.
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    Atractylenolide I enhances responsiveness to immune checkpoint blockade therapy by activating tumor antigen presentation
    (The American Society for Clinical Investigation, 2021-05-17) Xu, Hanchen; Van der Jeught, Kevin; Zhou, Zhuolong; Zhang, Lu; Yu, Tao; Sun, Yifan; Li, Yujing; Wan, Changlin; So, Ka Man; Liu, Degang; Frieden, Michael; Fang, Yuanzhang; Mosley, Amber L.; He, Xiaoming; Zhang, Xinna; Sandusky, George E.; Liu, Yunlong; Meroueh, Samy O.; Zhang, Chi; Wijeratne, Aruna B.; Huang, Cheng; Ji, Guang; Lu, Xiongbin; Medical and Molecular Genetics, School of Medicine
    One of the primary mechanisms of tumor cell immune evasion is the loss of antigenicity, which arises due to lack of immunogenic tumor antigens as well as dysregulation of the antigen processing machinery. In a screen for small-molecule compounds from herbal medicine that potentiate T cell–mediated cytotoxicity, we identified atractylenolide I (ATT-I), which substantially promotes tumor antigen presentation of both human and mouse colorectal cancer (CRC) cells and thereby enhances the cytotoxic response of CD8+ T cells. Cellular thermal shift assay (CETSA) with multiplexed quantitative mass spectrometry identified the proteasome 26S subunit non–ATPase 4 (PSMD4), an essential component of the immunoproteasome complex, as a primary target protein of ATT-I. Binding of ATT-I with PSMD4 augments the antigen-processing activity of immunoproteasome, leading to enhanced MHC-I–mediated antigen presentation on cancer cells. In syngeneic mouse CRC models and human patient–derived CRC organoid models, ATT-I treatment promotes the cytotoxicity of CD8+ T cells and thus profoundly enhances the efficacy of immune checkpoint blockade therapy. Collectively, we show here that targeting the function of immunoproteasome with ATT-I promotes tumor antigen presentation and empowers T cell cytotoxicity, thus elevating the tumor response to immunotherapy.
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    Cardiac Sca-1+ cells are not intrinsic stem cells for myocardial development, renewal and repair
    (American Heart Association, 2018-12-18) Zhang, Lu; Sultana, Nishat; Yan, Jianyun; Yang, Fan; Chen, Fuxue; Chepurko, Elena; Yang, Feng-Chun; Du, Qinghua; Zangi, Lior; Xu, Mingjiang; Bu, Lei; Cai, Chen-Leng; Pediatrics, School of Medicine
    Background: For over a decade, Sca-1+ cells within the mouse heart have been widely recognized as a stem cell population with multipotency that can give rise to cardiomyocytes, endothelial cells and smooth muscle cells in vitro and after cardiac grafting. However, the developmental origin and authentic nature of these cells remain elusive. Methods: Here, we used a series of high-fidelity genetic mouse models to characterize the identity and regenerative potential of cardiac resident Sca-1+ cells. Results: With these novel genetic mouse models, we found that Sca-1 does not label cardiac precursor cells during early embryonic heart formation. Postnatal cardiac resident Sca-1+ cells are in fact a pure endothelial cell population. They retain endothelial properties and exhibit minimal cardiomyogenic potential during development, normal aging and upon ischemic injury. Conclusions: Our study provides definitive insights into the nature of cardiac resident Sca-1+ cells. The observations challenge the current dogma that cardiac resident Sca-1+ cells are intrinsic stem cells for myocardial development, renewal and repair and suggest that the mechanisms of transplanted Sca-1+ cells in heart repair need to be reassessed.
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    Fluorination Enables Simultaneous Improvements of a Dialkoxybenzene-Based Redoxmer for Nonaqueous Redox Flow Batteries
    (American Chemical Society, 2022) Bheemireddy, Sambasiva R.; Li, Zhiguang; Zhang, Jingjing; Agarwal, Garvit; Robertson, Lily A.; Shkrob, Ilya A.; Assary, Rajeev S.; Zhang, Zhengcheng; Wei, Xiaoliang; Cheng, Lei; Zhang, Lu; Mechanical and Energy Engineering, Purdue School of Engineering and Technology
    Redoxmers or redox-active organic materials, are one critical component for nonaqueous redox flow batteries (RFBs), which hold high promise in enabling the time domain of the grid. While tuning redox potentials of redoxmers is a very effective way to enhance energy densities of NRFBs, those improvements often accompany accelerated kinetics of the charged species, undermining stability and cycling performance. Herein, a strategy for designing redoxmers with simultaneous improvements in redox potential and stability is proposed. Specifically, the redoxmer 1,4-di-tert-butyl-2,5-bis(2,2,2-trifluoroethoxy)benzene (ANL-C46) is developed by incorporating fluorinated substitutions into the dialkoxybenzene-based platform. Compared to the non-fluorinated analogue, ANL-C46 demonstrates not only an increased (∼0.41 V) redox potential but also much enhanced stability (1.6 times) and cyclability (4 times) evidenced by electron paramagnetic resonance kinetic study, H-cell and flow cell cycling. In fact, the cycling performance of ANL-C46 is among the best of high potential (>1.0 V vs Ag/Ag+) redoxmers ever reported. Density functional theory calculations suggest that while the introduced fluorine substitutions elevate the redox potentials, they also help to depress the decomposition reactions of the charged redoxmers, affording excellent stability. The findings represent an interesting strategy for simultaneously improving energy density and stability, which could further prompt the development of high-performance redoxmers.
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    Gene editing reverses arrhythmia susceptibility in humanized PLN-R14del mice: modelling a European cardiomyopathy with global impact
    (Oxford University Press, 2022) Dave, Jaydev; Raad, Nour; Mittal, Nishka; Zhang, Lu; Fargnoli, Anthony; Oh, Jae Gyun; Savoia, Maria Elisabetta; Hansen, Jens; Fava, Marika; Yin, Xiaoke; Theofilatos, Konstantinos; Ceholski, Delaine; Kohlbrenner, Erik; Jeong, Dongtak; Wills, Lauren; Nonnenmacher, Mathieu; Haghighi, Kobra; Costa, Kevin D.; Turnbull, Irene C.; Mayr, Manuel; Cai, Chen-Leng; Kranias, Evangelia G.; Akar, Fadi G.; Hajjar, Roger J.; Stillitano, Francesca; Pediatrics, School of Medicine
    Aims: A mutation in the phospholamban (PLN) gene, leading to deletion of Arg14 (R14del), has been associated with malignant arrhythmias and ventricular dilation. Identifying pre-symptomatic carriers with vulnerable myocardium is crucial because arrhythmia can result in sudden cardiac death, especially in young adults with PLN-R14del mutation. This study aimed at assessing the efficiency and efficacy of in vivo genome editing, using CRISPR/Cas9 and a cardiotropic adeno-associated virus-9 (AAV9), in improving cardiac function in young adult mice expressing the human PLN-R14del. Methods and results: Humanized mice were generated expressing human wild-type (hPLN-WT) or mutant (hPLN-R14del) PLN in the heterozygous state, mimicking human carriers. Cardiac magnetic resonance imaging at 12 weeks of age showed bi-ventricular dilation and increased stroke volume in mutant vs. WT mice, with no deficit in ejection fraction or cardiac output. Challenge of ex vivo hearts with isoproterenol and rapid pacing unmasked higher propensity for sustained ventricular tachycardia (VT) in hPLN-R14del relative to hPLN-WT. Specifically, the VT threshold was significantly reduced (20.3 ± 1.2 Hz in hPLN-R14del vs. 25.7 ± 1.3 Hz in WT, P < 0.01) reflecting higher arrhythmia burden. To inactivate the R14del allele, mice were tail-vein-injected with AAV9.CRISPR/Cas9/gRNA or AAV9 empty capsid (controls). CRISPR-Cas9 efficiency was evaluated by droplet digital polymerase chain reaction and NGS-based amplicon sequencing. In vivo gene editing significantly reduced end-diastolic and stroke volumes in hPLN-R14del CRISPR-treated mice compared to controls. Susceptibility to VT was also reduced, as the VT threshold was significantly increased relative to controls (30.9 ± 2.3 Hz vs. 21.3 ± 1.5 Hz; P < 0.01). Conclusions: This study is the first to show that disruption of hPLN-R14del allele by AAV9-CRISPR/Cas9 improves cardiac function and reduces VT susceptibility in humanized PLN-R14del mice, offering preclinical evidence for translatable approaches to therapeutically suppress the arrhythmogenic phenotype in human patients with PLN-R14del disease.
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    Heterozygous deletion of chromosome 17p renders prostate cancer vulnerable to inhibition of RNA polymerase II
    (Springer Nature, 2018-10-22) Li, Yujing; Liu, Yunhua; Xu, Hanchen; Jiang, Guanglong; Van der Jeught, Kevin; Fang, Yuanzhang; Zhou, Zhuolong; Zhang, Lu; Frieden, Michael; Wang, Lifei; Luo, Zhenhua; Radovich, Milan; Schneider, Bryan P.; Deng, Yibin; Liu, Yunlong; Huang, Kun; He, Bin; Wang, Jin; He, Xiaoming; Zhang, Xinna; Ji, Guang; Lu, Xiongbin; Medical and Molecular Genetics, School of Medicine
    Heterozygous deletion of chromosome 17p (17p) is one of the most frequent genomic events in human cancers. Beyond the tumor suppressor TP53, the POLR2A gene encoding the catalytic subunit of RNA polymerase II (RNAP2) is also included in a ~20-megabase deletion region of 17p in 63% of metastatic castration-resistant prostate cancer (CRPC). Using a focused CRISPR-Cas9 screen, we discovered that heterozygous loss of 17p confers a selective dependence of CRPC cells on the ubiquitin E3 ligase Ring-Box 1 (RBX1). RBX1 activates POLR2A by the K63-linked ubiquitination and thus elevates the RNAP2-mediated mRNA synthesis. Combined inhibition of RNAP2 and RBX1 profoundly suppress the growth of CRPC in a synergistic manner, which potentiates the therapeutic effectivity of the RNAP2 inhibitor, α-amanitin-based antibody drug conjugate (ADC). Given the limited therapeutic options for CRPC, our findings identify RBX1 as a potentially therapeutic target for treating human CRPC harboring heterozygous deletion of 17p.
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    Human Endogenous Retrovirus, SARS-CoV-2, and HIV Promote PAH via Inflammation and Growth Stimulation
    (MDPI, 2023-04-18) Wang, Desheng; Gomes, Marta T.; Mo, Yanfei; Prohaska, Clare C.; Zhang, Lu; Chelvanambi, Sarvesh; Clauss, Matthias A.; Zhang, Dongfang; Machado, Roberto F.; Gao, Mingqi; Bai, Yang; Medicine, School of Medicine
    Pulmonary arterial hypertension (PAH) is a pulmonary vascular disease characterized by the progressive elevation of pulmonary arterial pressures. It is becoming increasingly apparent that inflammation contributes to the pathogenesis and progression of PAH. Several viruses are known to cause PAH, such as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), human endogenous retrovirus K(HERV-K), and human immunodeficiency virus (HIV), in part due to acute and chronic inflammation. In this review, we discuss the connections between HERV-K, HIV, SARS-CoV-2, and PAH, to stimulate research regarding new therapeutic options and provide new targets for the treatment of the disease.
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    Limited Regeneration Potential with Minimal Epicardial Progenitor Conversions in the Neonatal Mouse Heart after Injury
    (Elsevier, 2019-07-02) Cai, Weibin; Tan, Jing; Yan, Jianyun; Zhang, Lu; Cai, Xiaoqiang; Wang, Haiping; Liu, Fang; Ye, Maoqing; Cai, Chen-Leng; Pediatrics, School of Medicine
    The regeneration capacity of neonatal mouse heart is controversial. In addition, whether epicardial cells provide a progenitor pool for de novo heart regeneration is incompletely defined. Following apical resection of the neonatal mouse heart, we observed limited regeneration potential. Fate-mapping of Tbx18MerCreMer mice revealed that newly formed coronary vessels and a limited number of cardiomyocytes were derived from the T-box transcription factor 18 (Tbx18) lineage. However, further lineage tracing with SM-MHCCreERT2 and Nfactc1Cre mice revealed that the new smooth muscle and endothelial cells are in fact derivatives of pre-existing coronary vessels. Our data show that neonatal mouse heart can regenerate but that its potential is limited. Moreover, although epicardial cells are multipotent during embryogenesis, their contribution to heart repair through "stem" or "progenitor" cell conversion is minimal after birth. These observations suggest that early embryonic heart development and postnatal heart regeneration are distinct biological processes. Multipotency of epicardial cells is significantly decreased after birth.
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    Multielectron Organic Redoxmers for Energy-Dense Redox Flow Batteries
    (ACS, 2022-01) Fang, Xiaoting; Li, Zhiguang; Zhao, Yuyue; Yue, Diqing; Zhang, Lu; Wei, Xiaoliang; Mechanical Engineering, School of Engineering and Technology
    Redox flow battery is a highly promising stationary energy storage method, but the limited energy density and high chemical cost are among the main barriers for commercialization. Multielectron organic redoxmers represent a family of structurally tailorable candidates that can achieve multiplied energy density with decreased materials consumption, potentially resulting in a viable solution to address these challenges. Here, the recent development of organic molecules with reversible multiredox activities in both aqueous and nonaqueous electrolytes is reviewed. The major focus is on the fundamental correlation between the chemical structures and the functional properties of reported multielectron organic molecules. Valuable insights are offered on rational structural design strategies for improving the relevant physicochemical and electrochemical properties. Finally, the current challenges are discussed to suggest future research needs along the avenue of using the multielectron approach to achieve energy-dense, stable, cost-effective redox flow batteries.
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    Novel Myh11 Dual Reporter Mouse Model Provides Definitive Labeling and Identification of Smooth Muscle Cells—Brief Report
    (AHA, 2021-02) Ruan, Jian; Zhang, Lu; Hu, Donghua; Qu, Xianghu; Yang, Fan; Chen, Fuxue; He, Xiangqin; Shen, Jian; Dong, Kunzhe; Sweet, Megan; Sanchez, Christina; Li, Deqiang; Shou, Weinian; Zhou, Jiliang; Cai, Chen-Leng; Pediatrics, School of Medicine
    Objective: Myh11 encodes a myosin heavy chain protein that is specifically expressed in smooth muscle cells (SMCs) and is important for maintaining vascular wall stability. The goal of this study is to generate a Myh11 dual reporter mouse line for definitive visualization of MYH11+ SMCs in vivo. Approach and Results: We generated a Myh11 knock-in mouse model by inserting LoxP-nlacZ-4XpolyA-LoxP-H2B-GFP-polyA-FRT-Neo-FRT reporter cassette into the Myh11 gene locus. The nuclear (n) lacZ-4XpolyA cassette is flanked by 2 LoxP sites followed by H2B-GFP (histone 2B fused green fluorescent protein). Upon Cre-mediated recombination, nlacZ-stop cassette is removed thereby permitting nucleus localized H2B-GFP expression. Expression of the nuclear localized lacZ or H2B-GFP is under control of the endogenous Myh11 promoter. Nuclear lacZ was expressed specifically in SMCs at embryonic and adult stages. Following germline Cre-mediated deletion of nuclear lacZ, H2B-GFP was specifically expressed in the nuclei of SMCs. Comparison of nuclear lacZ expression with Wnt1Cre and Mef2cCre mediated-H2B-GFP expression revealed heterogenous origins of SMCs from neural crest and second heart field in the great arteries and coronary vessels adjacent to aortic root. Conclusions: The Myh11 knock-in dual reporter mouse model offers an exceptional genetic tool to visualize and trace the origins of SMCs in mice.