Stem cell transplantation has emerged as a promising strategy in regenerative medicine. However, the poor survival and persistence of the transplanted cells, including mesenchymal stem cells (MSCs), in the hostile ischemic microenvironments represents a major therapeutic barrier. Here we report that plasminogen (Plg) stimulated MSC functions and promoted MSC survival during tissue repair after ischemia. Genetic Plg ablation abolished MSC survival, migration, and proliferation in mouse ischemic limbs, and abrogated MSC-mediated blood reperfusion, neovascularization, and tissue repair after ischemia, suggesting a critical role for Plg in MSC-mediated tissue repair. Furthermore, multiplex cytokine array analysis identified that Plg cleaved and activated cysteine-rich protein 61 (Cyr61), an ECM-associated growth factor, to stimulate MSC survival and migration. Overexpression with truncated Cyr61 in MSCs rescued blood reperfusion after hind limb ischemia in Plg-deficient mice. Finally, Plg-mediated Cyr61 cleavage promoted endothelial cell migration and neovascularization in vitro and in vivo. Our study reveals that Plg promotes MSC survival, persistence, and paracrine effects and improves postischemic neovascularization and tissue repair through Cyr61 cleavage and activation. Thus, targeting Plg/Cyr61 may offer exciting therapeutic opportunities for strengthening MSC therapy in ischemic diseases.
Hao Duan, Zhenqiang He, Maohuan Lin, Yanling Wang, Fan Yang, R. Alan Mitteer, Hyun-Jun Kim, Eujing Yeo, Hongyu Han, Ling Qin, Yi Fan, Yanqing Gong
Prostaglandin E2 and its cognate EP1–4 receptors play important roles in blood pressure (BP) regulation. Herein, we show that endothelial cell–specific (EC-specific) EP4 gene–knockout mice (EC-EP4–/–) exhibited elevated, while EC-specific EP4-overexpression mice (EC-hEP4OE) displayed reduced, BP levels compared with the control mice under both basal and high-salt diet–fed conditions. The altered BP was completely abolished by treatment with l–NG-nitro-l-arginine methyl ester (l-NAME), a competitive inhibitor of endothelial nitric oxide synthase (eNOS). The mesenteric arteries of the EC-EP4–/– mice showed increased vasoconstrictive response to angiotensin II and reduced vasorelaxant response to acetylcholine, both of which were eliminated by l-NAME. Furthermore, EP4 activation significantly reduced BP levels in hypertensive rats. Mechanistically, EP4 deletion markedly decreased NO contents in blood vessels via reducing eNOS phosphorylation at Ser1177. EP4 enhanced NO production mainly through the AMPK pathway in cultured ECs. Collectively, our findings demonstrate that endothelial EP4 is essential for BP homeostasis.
Hu Xu, Bingying Fang, Shengnan Du, Sailun Wang, Qingwei Li, Xiao Jia, Chengzhen Bao, Lan Ye, Xue Sui, Lei Qian, Zhilin Luan, Guangrui Yang, Feng Zheng, Nanping Wang, Lihong Chen, Xiaoyan Zhang, Youfei Guan
Despite advances in lipid-lowering therapies, people with diabetes continue to experience more limited cardiovascular benefits. In diabetes, hyperglycemia sustains inflammation and preempts vascular repair. We tested the hypothesis that the receptor for advanced glycation end-products (RAGE) contributes to these maladaptive processes. We report that transplantation of aortic arches from diabetic, Western diet–fed Ldlr—/— mice into diabetic Ager—/— (Ager, the gene encoding RAGE) versus WT diabetic recipient mice accelerated regression of atherosclerosis. RNA-sequencing experiments traced RAGE-dependent mechanisms principally to the recipient macrophages and linked RAGE to interferon signaling. Specifically, deletion of Ager in the regressing diabetic plaques downregulated interferon regulatory factor 7 (Irf7) in macrophages. Immunohistochemistry studies colocalized IRF7 and macrophages in both murine and human atherosclerotic plaques. In bone marrow–derived macrophages (BMDMs), RAGE ligands upregulated expression of Irf7, and in BMDMs immersed in a cholesterol-rich environment, knockdown of Irf7 triggered a switch from pro- to antiinflammatory gene expression and regulated a host of genes linked to cholesterol efflux and homeostasis. Collectively, this work adds a new dimension to the immunometabolic sphere of perturbations that impair regression of established diabetic atherosclerosis and suggests that targeting RAGE and IRF7 may facilitate vascular repair in diabetes.
Laura Senatus, Raquel López-Díez, Lander Egaña-Gorroño, Jianhua Liu, Jiyuan Hu, Gurdip Daffu, Qing Li, Karishma Rahman, Yuliya Vengrenyuk, Tessa J. Barrett, M. Zahidunnabi Dewan, Liang Guo, Daniela Fuller, Aloke V. Finn, Renu Virmani, Huilin Li, Richard A. Friedman, Edward A. Fisher, Ravichandran Ramasamy, Ann Marie Schmidt
Following myocardial infarction (MI), the adult heart has minimal regenerative potential. Conversely, the neonatal heart can undergo extensive regeneration, and neovascularisation capacity was hypothesised to contribute to this difference. Here, we demonstrate the higher angiogenic potential of neonatal compared to adult mouse cardiac endothelial cells (MCECs) in vitro and use this difference to identify candidate microRNAs (miRs) regulating cardiac angiogenesis after MI. MiR expression profiling revealed miR-96 and miR-183 upregulation in adult compared to neonatal MCECs. Their overexpression decreased the angiogenic potential of neonatal MCECs in vitro and prevented scar resolution and neovascularisation in neonatal mice after MI. Inversely, their inhibition improved the angiogenic potential of adult MCECs, and miR-96/miR-183 knock-out mice had increased peri-infarct neovascularisation. In silico analyses identified anillin (ANLN) as a direct target of miR-96 and miR-183. In agreement, Anln expression declined following their overexpression and increased after their inhibition in vitro. Moreover, ANLN expression inversely correlated with miR-96 expression and age in cardiac ECs of cardiovascular patients. In vivo, ANLN-positive vessels were enriched in the peri-infarct area of miR-96/miR-183 knock-out mice. These findings identify miR-96 and miR-183 as regulators of neovascularisation following MI and miR-regulated genes such as anillin as potential therapeutic targets for cardiovascular disease.
Raphael F.P. Castellan, Milena Vitiello, Martina Vidmar, Steven Johnstone, Dominga Iacobazzi, David Mellis, Benjamin Cathcart, Adrian JW Thomson, Christiana Ruhrberg, Massimo Caputo, David E. Newby, Gillian A. Gray, Andrew Howard Baker, Andrea Caporali, Marco Meloni
During the growth of lymphatic vessels (lymphangiogenesis), lymphatic endothelial cells (LECs) at the growing front sprout by forming filopodia. Those tip cells are not exposed to circulating lymph, as they are not lumenized. In contrast, LECs that trail the growing front are exposed to shear stress, become quiescent and remodel into stable vessels. The mechanisms that coordinate the opposed activities of lymphatic sprouting and maturation remain poorly understood. Here we show that the canonical tip cell marker Delta-Like 4 (DLL4) promotes sprouting lymphangiogenesis by enhancing Vascular Endothelial Growth Factor C (VEGF-C) /VEGF Receptor 3 (VEGFR3) signaling. However, in lumenized lymphatic vessels laminar shear stress (LSS) inhibits the expression of DLL4, as well as additional tip cell markers. Paradoxically, LSS also upregulates VEGF-C/VEGFR3 signaling in LECs, but sphingosine 1-phosphate (S1P) receptor 1 (S1PR1) activity antagonizes LSS-mediated VEGF-C signaling to promote lymphatic vascular quiescence. Correspondingly, S1pr1 loss in LECs induced lymphatic vascular hypersprouting and hyperbranching, which could be rescued by reducing Vegfr3 gene dosage in vivo. In addition, S1PR1 regulates lymphatic vessel maturation by inhibiting RhoA activity to promote membrane localization of the tight junction molecule Claudin-5. Our findings suggest a new paradigm in which LSS induces quiescence and promotes the survival of LECs by downregulating DLL4 and enhancing VEGF-C signaling, respectively. S1PR1 dampens LSS/VEGF-C signaling, thereby preventing sprouting from quiescent lymphatic vessels. These results also highlight the distinct roles that S1PR1 and DLL4 play in LECs when compared to their known roles in the blood vasculature.
Xin Geng, Keisuke Yanagida, Racheal G. Akwii, Dongwon Choi, Lijuan Chen, YenChun Ho, Boksik Cha, Md. Riaj Mahamud, Karen Berman de Ruiz, Hirotake Ichise, Hong Chen, Joshua Wythe, Constantinos M. Mikelis, Timothy Hla, R. Sathish Srinivasan
Patients with hereditary or acquired hemolytic anemias have a high risk of developing in-situ thrombosis of the pulmonary vasculature. While pulmonary thrombosis is a major morbidity associated with hemolytic disorders, the etiological mechanism underlying hemolysis-induced pulmonary thrombosis remains largely unknown. Here, we use intravital lung microscopy in mice for the first time to assess the pathogenesis of pulmonary thrombosis following deionized-water induced acute intravascular hemolysis. Acute hemolysis triggered the development of αIIbβ3-dependent platelet-rich thrombi in precapillary pulmonary arterioles, which led to the transient impairment of pulmonary blood flow. The hemolysis-induced pulmonary thrombosis was phenocopied with intravenous ADP- but not thrombin-triggered pulmonary thrombosis. Consistent with a mechanism involving ADP release from hemolyzing erythrocytes, the inhibition of platelet-P2Y12 purinergic-receptor signaling attenuated pulmonary thrombosis and rescued blood flow in the pulmonary arterioles of mice following intravascular hemolysis. These findings are the first in vivo studies to suggest that acute intravascular hemolysis promotes ADP-dependent platelet activation leading to thrombosis in the pre-capillary pulmonary arterioles and that thrombin generation most likely does not play a significant role in the pathogenesis of acute hemolysis-triggered pulmonary thrombosis.
Tomasz Brzoska, Ravi Vats, Margaret F. Bennewitz, Egemen Tutuncuoglu, Simon C. Watkins, Margaret V. Ragni, Matthew D. Neal, Mark T. Gladwin, Prithu Sundd
Genetic or acquired defects of the lymphatic vasculature often result in disfiguring, disabling and, occasionally, life-threatening clinical consequences. Advanced forms of lymphedema are readily diagnosed clinically, but more subtle presentations often require invasive imaging or other technologies for a conclusive diagnosis. On the other hand, lipedema, a chronic lymphatic microvascular disease with pathological accumulation of subcutaneous adipose tissue is often misdiagnosed as obesity or lymphedema; currently there are no biomarkers or imaging criteria available for a conclusive diagnosis. Recent evidence suggests that otherwise asymptomatic defective lymphatic vasculature likely contributes to an array of other pathologies, including obesity, inflammatory bowel disease and neurological disorders, among others. Accordingly, identification of biomarkers of lymphatic malfunction will provide a valuable resource for the diagnosis and clinical discrimination of lymphedema, lipedema, obesity and other potential lymphatic-related pathologies. In this paper we profiled and compared blood plasma exosomes isolated from mouse models and from human subjects with and without symptomatic lymphatic pathologies. We identified platelet factor 4 (PF4/CXCL4) as a biomarker that could be used to diagnose lymphatic vasculature dysfunction. Furthermore, we determined that PF4 levels in circulating blood plasma exosomes were also elevated in lipedema patients, supporting current claims arguing that at least some of the underlying attributes of this disease are also the consequence of lymphatic defects.
Wanshu Ma, Hyea Jin Gil, Noelia Escobedo, Alberto Benito-Martín, Pilar Ximénez-Embún, Javier Muñoz, Héctor Peinado, Stanley G. Rockson, Guillermo Oliver
Increased microvascular leakage is a cardinal feature of many critical diseases. Regular exercise is associated with improved endothelial function and reduced risk of cardiovascular disease. Irisin, secreted during exercise, contributes to many health benefits of exercise. However, the effects of irisin on endothelial function and microvascular leakage remain unknown. In this study, we found that irisin remarkably strengthened endothelial junctions and barrier function via binding to integrin αVβ5 receptor in LPS-treated endothelial cells. The beneficial effect of irisin was associated with suppression of the Src-MLCK-β-catenin pathway, activation of the AMPK-Cdc42/Rac1 pathway and improvement of mitochondrial function. In preclinical models of microvascular leakage, exogenous irisin improved pulmonary function, decreased lung edema and injury, suppressed inflammation, and increased survival. In ARDS patients, serum irisin levels were decreased and inversely correlated with disease severity and mortality. In conclusion, irisin enhances endothelial barrier function and mitigates microvascular leakage related diseases.
Jianbin Bi, Jia Zhang, Yifan Ren, Zhaoqing Du, Yuanyuan Zhang, Chang Liu, Yawen Wang, Lin Zhang, Zhihong Shi, Zheng Wu, Yi Lv, Rongqian Wu
The ability of Mycobacterium tuberculosis to form serpentine cords is intrinsically related to its virulence, but specifically how M. tuberculosis cording contributes to pathogenesis remains obscure. We show that several M. tuberculosis clinical isolates form intracellular cords in primary human lymphatic endothelial cells (hLEC) in vitro and also in the lymph nodes of patients with tuberculosis. We identified via RNA-seq a transcriptional programme that activates, in infected-hLECs, cell-survival and cytosolic surveillance of pathogens pathways. Consistent with this, cytosolic access is required for intracellular M. tuberculosis cording. Mycobacteria lacking ESX-1 type VII secretion system or PDIM expression, which fail to access to the cytosol, are indeed unable to cords within hLECs. Finally, we show that M. tuberculosis cording is a size-dependent mechanism used by the pathogen to avoid its recognition by cytosolic sensors and evade either resting or IFN-γ-induced hLEC immunity. These results explain the long-standing association between M. tuberculosis cording and virulence and how virulent mycobacteria use intracellular cording as strategy to successfully adapt and persist in the lymphatic tracts.
Thomas R. Lerner, Christophe J. Queval, Rachel PJ Lai, Matthew Robert Geoffrey Russell, Antony Fearns, Daniel J. Greenwood, Lucy Collinson, Robert J. Wilkinson, Maximiliano G. Gutierrez
Ischemic retinopathies are major causes of blindness worldwide. Local hypoxia created by loss of vascular supply leads to tissue injury and aberrant neovascularization in the retina. There is a great need for therapies that enhance revascularization of hypoxic neuroretinal tissue. To test the therapeutic feasibility of human-induced pluripotent stem cell–derived endothelial cells (hiPSC-ECs) for the treatment of ischemic retinopathies, we compared the angiogenic potential of hiPSC-ECs with mature human retinal endothelial cells (HRECs) in response to hypoxia. hiPSC-ECs formed more robust and complex vascular networks in collagen gels, whereas HRECs displayed minimal sprouting. The cells were further tested in the mouse oxygen-induced retinopathy (OIR) model. Retinas with hiPSC-EC injection showed colocalization with host vessels, whereas HRECs lacked such responses. hiPSC-ECs markedly reduced vaso-obliteration and pathological neovascularization. This beneficial effect of hiPSC-ECs was explained by the stromal cell–derived factor-1a (SDF1a)/CXCR4 axis; hiPSC-ECs exhibited much higher cell-surface expression of CXCR4 than HRECs and greater chemotaxis toward SDF1a-embedded 3D collagen hydrogel. Furthermore, treatment with neutralizing antibody to CXCR4 abolished recruitment of hiPSCs in the OIR model. These findings suggest superior angiogenic potential of hiPSC-ECs under hypoxia and underscore the importance of SDF1a/CXCR4 in the reparative function of hiPSC-ECs in ischemic diseases.
Hongkwan Cho, Bria L. Macklin, Ying-Yu Lin, Lingli Zhou, Michael J. Lai, Grace Lee, Sharon Gerecht, Elia J. Duh
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