There are more than 7000 described rare diseases, most lacking specific treatment. Autosomal-dominant hyper-IgE syndrome (AD-HIES, Job’s syndrome) is caused by mutations in signal transducer and activator of transcription 3 (STAT3). These patients present with immunodeficiency accompanied by severe non-immunological features including skeletal, connective tissue and vascular abnormalities, poor post-infection lung healing, and subsequent pulmonary failure. No specific therapies are available for these abnormalities. Here we investigated underlying mechanisms in order to identify therapeutic targets. Histological analysis of skin wounds demonstrated delayed granulation tissue formation and vascularization during skin wound healing in AD-HIES patients. Global gene expression analysis in AD-HIES patient skin fibroblasts identified deficiencies in a STAT3 controlled transcriptional network regulating extracellular matrix (ECM) remodeling and angiogenesis, with hypoxia inducible factor 1α (HIF1α) being a major contributor. Consistent with this, histological analysis of skin wounds and coronary arteries from AD-HIES patients showed decreased HIF1α expression, and revealed abnormal organization of the ECM and altered formation of the coronary vasa vasorum. Disease modeling utilizing cell culture and mouse models of angiogenesis and wound healing confirmed these predicted deficiencies and demonstrated therapeutic benefit of HIF1α stabilizing drugs. The study provides mechanistic insights into AD-HIES pathophysiology and finds new treatment option for this rare disease.
Natalia I. Dmitrieva, Avram D. Walts, Dai P. Nguyen, Alex Grubb, Xue Zhang, Xujing Wang, Xianfeng Ping, Hui Jin, Zhen Yu, Zu-Xi Yu, Dan Yang, Robin Schwartzbeck, Clifton L. Dalgard, Beth A. Kozel, Mark D. Levin, Russell H. Knutsen, Delong Liu, Joshua D. Milner, Diego B. López, Michael P. O'Connell, Chyi-Chia R. Lee, Ian A. Myles, Amy P. Hsu, Alexandra F. Freeman, Steven M. Holland, Guibin Chen, Manfred Boehm
Unchecked inflammation is a hallmark of inflammatory tissue injury in diseases such as acute respiratory distress syndrome (ARDS). Yet the mechanisms of inflammatory lung injury remain largely unknown. Here we showed that bacterial endotoxin lipopolysaccharide (LPS) and cecal ligation and puncture (CLP)-induced polymicrobial sepsis decreased the expression of transcription factor cAMP Response Element Binding (CREB) in lung endothelial cells. We demonstrated that endothelial CREB was crucial for VE-cadherin transcription and the formation of the normal restrictive endothelial adherens junctions. The inflammatory cytokine IL-1β reduced cAMP generation and CREB-mediated transcription of VE-cadherin. Furthermore, endothelial cell-specific deletion of CREB induced lung vascular injury whereas ectopic expression of CREB in the endothelium prevented the injury. We also observed that rolipram, which inhibits PDE4-mediated hydrolysis of cAMP, prevented endotoxemia-induced lung vascular injury since it preserved CREB-mediated VE-cadherin expression. These data demonstrate the fundamental role of endothelial cAMP-CREB axis in promoting lung vascular integrity and suppressing inflammatory injury. Therefore, strategies aimed at enhancing endothelial CREB-mediated VE-cadherin transcription are potentially useful in preventing sepsis-induced lung vascular injury in ARDS.
Shiqin Xiong, Zhigang Hong, Long Shuang Huang, Yoshikazu Tsukasaki, Saroj Nepal, Anke Di, Ming Zhong, Wei Wu, Zhiming Ye, XiaoPei Gao, Gadiparthi Rao, Dolly Mehta, Jalees Rehman, Asrar B. Malik
The atypical cadherin FAT4 has established roles in regulation of planar cell polarity and Hippo pathway signaling that are cell context dependent. The recent identification of FAT4 mutations in Hennekam syndrome, features of which include lymphedema, lymphangiectasia and mental retardation, uncovered an important role for FAT4 in the lymphatic vasculature. Hennekam syndrome is also caused by mutations in CCBE1 and ADAMTS3, encoding a matrix protein and protease, respectively, that regulate activity of the key pro-lymphangiogenic VEGF-C/VEGFR3 signaling axis by facilitating the proteolytic cleavage and activation of VEGF-C. The fact that FAT4, CCBE1 and ADAMTS3 mutations underlie Hennekam syndrome suggested that all three genes might function in a common pathway. We identified FAT4 as a target gene of GATA2, a key transcriptional regulator of lymphatic vascular development and in particular, lymphatic vessel valve development. Here, we demonstrate that FAT4 functions in a lymphatic endothelial cell autonomous manner to control cell polarity in response to flow and is required for lymphatic vessel morphogenesis throughout development. Our data reveal a crucial role for FAT4 in lymphangiogenesis and shed light on the mechanistic basis by which FAT4 mutations underlie a human lymphedema syndrome.
Kelly L. Betterman, Drew L. Sutton, Genevieve A. Secker, Jan Kazenwadel, Anna Oszmiana, Lillian Lim, Naoyuki Miura, Lydia Sorokin, Benjamin M. Hogan, Mark L. Kahn, Helen McNeill, Natasha L. Harvey
Smooth muscle cell (SMC) proliferation has been thought to limit the progression of thoracic aortic aneurysm and dissection (TAAD) because loss of medial cells associates with advanced disease. We investigated effects of SMC proliferation in the aortic media by conditional disruption of Tsc1, which hyperactivates mTOR complex 1. Consequent SMC hyperplasia led to progressive medial degeneration and TAAD. In addition to diminished contractile and synthetic functions, fate-mapped SMCs displayed increased proteolysis, endocytosis, phagocytosis, and lysosomal clearance of extracellular matrix and apoptotic cells. SMCs acquired a limited repertoire of macrophage markers and functions via biogenesis of degradative organelles through an mTOR/β-catenin/MITF–dependent pathway, but were distinguishable from conventional macrophages by an absence of hematopoietic lineage markers and certain immune effectors even in the context of hyperlipidemia. Similar mTOR activation and induction of a degradative SMC phenotype in a model of mild TAAD due to Fbn1 mutation greatly worsened disease with near-uniform lethality. The finding of increased lysosomal markers in medial SMCs from clinical TAAD specimens with hyperplasia and matrix degradation further supports the concept that proliferation of degradative SMCs within the media causes aortic disease, thus identifying mTOR-dependent phenotypic modulation as a therapeutic target for combating TAAD.
Guangxin Li, Mo Wang, Alexander W. Caulk, Nicholas A. Cilfone, Sharvari Gujja, Lingfeng Qin, Pei-Yu Chen, Zehua Chen, Sameh Yousef, Yang Jiao, Changshun He, Bo Jiang, Arina Korneva, Matthew R. Bersi, Guilin Wang, Xinran Liu, Sameet Mehta, Arnar Geirsson, Jeffrey R. Gulcher, Thomas W. Chittenden, Michael Simons, Jay D. Humphrey, George Tellides
Increased microvascular permeability to plasma proteins and neutrophil emigration are hallmarks of innate immunity and key features of numerous inflammatory disorders. Whilst neutrophils can promote microvascular leakage, the impact of vascular permeability on neutrophil trafficking is unknown. Here, through the application of confocal intravital microscopy, we reported that vascular permeability enhancing stimuli caused a significant frequency of neutrophil reverse transendothelial cell migration (rTEM). Furthermore, mice with a selective defect in microvascular permeability enhancement (VEC-Y685F-ki) showed reduced incidence of rTEM. Mechanistically, elevated vascular leakage promoted movement of interstitial chemokines into the blood stream, a response that supported abluminal-to-luminal neutrophil TEM. Through development of an in vivo cell labelling method we provided direct evidence for the systemic dissemination of rTEM neutrophils, showed them to exhibit an activated phenotype and capable of trafficking to the lungs where their presence was aligned with regions of vascular injury. Collectively, we demonstrated that increased microvascular leakage reverses the localisation of directional cues across venular walls, thus causing neutrophils engaged in diapedesis to re-enter the systemic circulation. This cascade of events offers a mechanism to explain how local tissue inflammation and vascular permeability can induce downstream pathological effects in remote organs, most notably in the lungs.
Charlotte Owen-Woods, Régis Joulia, Anna Barkaway, Loïc Rolas, Bin Ma, Astrid Fee Nottebaum, Kenton P. Arkill, Monja Stein, Tamara Girbl, Matthew Golding, David O. Bates, Dietmar Vestweber, Mathieu-Benoit Voisin, Sussan Nourshargh
Cantu Syndrome (CS) is a complex disorder caused by gain-of-function (GoF) mutations in ABCC9 and KCNJ8, which encode the SUR2 and Kir6.1 subunits, respectively, of vascular smooth muscle (VSM) KATP channels. CS includes dilated vasculature, marked cardiac hypertrophy, and other cardiovascular abnormalities. There is currently no targeted therapy, and it is unknown whether cardiovascular features can be reversed once manifest. Using combined transgenic and pharmacological approaches in a knock-in mouse model of CS, we have shown that reversal of vascular and cardiac phenotypes can be achieved (1) by genetic downregulation of KATP channel activity specifically in VSM, and (2) by chronic administration of the clinically-used KATP channel inhibitor, glibenclamide. These findings demonstrate (i) that VSM KATP channel GoF underlies CS cardiac enlargement, (ii) reversibility of CS-associated abnormalities and (iii) evidence of in vivo efficacy of glibenclamide as a therapeutic agent in CS.
Conor McClenaghan, Yan Huang, Zihan Yan, Theresa Harter, Carmen M. Halabi, Rod Chalk, Attila Kovacs, Gijs van Haaften, Maria S. Remedi, Colin G. Nichols
Fibronectin–splice variant containing extra domain A (Fn-EDA) is associated with smooth muscle cells (SMCs) following vascular injury. The role of SMC-derived Fn-EDA in SMC phenotypic switching or its implication in neointimal hyperplasia remains unclear. Herein, using human coronary artery sections with a bare metal stent, we demonstrate the expression of Fn-EDA in the vicinity of SMC-rich neointima and peri-strut areas. In mice, Fn-EDA colocalizes with SMCs in the neointima of injured carotid arteries and promotes neointima formation in the comorbid condition of hyperlipidemia by potentiating SMC proliferation and migration. No sex-based differences were observed. Mechanistic studies suggested that Fn-EDA mediates integrin- and TLR4-dependent proliferation and migration through activation of FAK/Src and Akt1/mTOR signaling, respectively. Specific deletion of Fn-EDA in SMCs, but not in endothelial cells, reduced intimal hyperplasia and suppressed the SMC synthetic phenotype concomitant with decreased Akt1/mTOR signaling. Targeting Fn-EDA in human aortic SMCs suppressed the synthetic phenotype and downregulated Akt1/mTOR signaling. These results reveal that SMC-derived Fn-EDA potentiates phenotypic switching in human and mouse aortic SMCs and neointimal hyperplasia in the mouse. We suggest that targeting Fn-EDA could be explored as a potential therapeutic strategy to reduce neointimal hyperplasia.
Manish Jain, Nirav Dhanesha, Prakash Doddapattar, Mehul R. Chorawala, Manasa K. Nayak, Anne Cornelissen, Liang Guo, Aloke V. Finn, Steven R. Lentz, Anil K. Chauhan
Background: Ceramides are sphingolipids that play causative roles in diabetes and heart disease, with their serum levels measured clinically as biomarkers of cardiovascular disease (CVD). Methods: We performed targeted lipidomics on serum samples of individuals with familial coronary artery disease (CAD) (n = 462) and population-based controls (n = 212) to explore the relationship between serum sphingolipids and CAD, employing unbiased machine learning to identify sphingolipid species positively associated with CAD. Results: Nearly every sphingolipid measured (n = 30 of 32) was significantly elevated in subjects with CAD compared with population controls. We generated a novel Sphingolipid Inclusive CAD risk score, termed SIC, that demarcates CAD patients independently and more effectively than conventional clinical CVD biomarkers including LDL-cholesterol and serum triglycerides. This new metric comprises several minor lipids which likely serve as measures of flux through the ceramide biosynthesis pathway, rather than the abundant deleterious ceramide species that are incorporated in other ceramide-based scores. Conclusion: This study validates serum ceramides as candidate biomarkers of cardiovascular disease and suggests that comprehensive sphingolipid panels be considered as measures of CVD.
Annelise M. Poss, J. Alan Maschek, James E. Cox, Benedikt J. Hauner, Paul N. Hopkins, Steven C. Hunt, William L. Holland, Scott A. Summers, Mary C. Playdon
Deep venous thrombosis (DVT) and secondary pulmonary embolism cause approximately 100,000 deaths per year in the United States. Physical immobility is the most significant risk factor for DVT, but a molecular and cellular basis for this link has not been defined. We found that the endothelial cells surrounding the venous valve, where DVTs originate, express high levels of FOXC2 and PROX1, transcription factors known to be activated by oscillatory shear stress. The perivalvular venous endothelial cells exhibited a powerful antithrombotic phenotype characterized by low levels of the prothrombotic proteins vWF, P-selectin, and ICAM1 and high levels of the antithrombotic proteins thrombomodulin (THBD), endothelial protein C receptor (EPCR), and tissue factor pathway inhibitor (TFPI). The perivalvular antithrombotic phenotype was lost following genetic deletion of FOXC2 or femoral artery ligation to reduce venous flow in mice, and at the site of origin of human DVT associated with fatal pulmonary embolism. Oscillatory blood flow was detected at perivalvular sites in human veins following muscular activity, but not in the immobile state or after activation of an intermittent compression device designed to prevent DVT. These findings support a mechanism of DVT pathogenesis in which loss of muscular activity results in loss of oscillatory shear–dependent transcriptional and antithrombotic phenotypes in perivalvular venous endothelial cells, and suggest that prevention of DVT and pulmonary embolism may be improved by mechanical devices specifically designed to restore perivalvular oscillatory flow.
John D. Welsh, Mark H. Hoofnagle, Sharika Bamezai, Michael Oxendine, Lillian Lim, Joshua D. Hall, Jisheng Yang, Susan Schultz, James Douglas Engel, Tsutomu Kume, Guillermo Oliver, Juan M. Jimenez, Mark L. Kahn
Leptomeningeal anastomoses or pial collateral vessels play a critical role in cerebral blood flow (CBF) restoration following ischemic stroke. The magnitude of this adaptive response is postulated to be controlled by the endothelium, although the underlying molecular mechanisms remain under investigation. Here we demonstrated that endothelial genetic deletion, using EphA4f/f/Tie2-Cre and EphA4f/f/VeCahderin-CreERT2 mice and vessel painting strategies, implicated EphA4 receptor tyrosine kinase as a major suppressor of pial collateral remodeling, CBF and functional recovery following permanent middle cerebral artery occlusion. Pial collateral remodeling is limited by the cross talk between EphA4-Tie2 signaling in vascular endothelial cells, which is mediated through p-Akt regulation. Furthermore, peptide inhibition of EphA4 resulted in acceleration of the pial arteriogenic response. Our findings demonstrate EphA4 is a negative regulator of Tie2 receptor signaling which limits pial collateral arteriogenesis following cerebrovascular occlusion. Therapeutic targeting of EphA4 and/or Tie2 represents an attractive new strategy for improving collateral function, neural tissue health and functional recovery following ischemic stroke.
Benjamin Okyere, William A. Mills III, Xia Wang, Michael Chen, Jiang Chen, Amanda Hazy, Yun Qian, John B. Matson, Michelle H. Theus