Pathologic lymphatic remodeling in lymphedema evolves during periods of tissue inflammation and hypoxia through poorly defined processes. In human and mouse lymphedema, there is a significant increase of hypoxia inducible factor (HIF)-1α, but a reduction of HIF-2α protein expression in lymphatic endothelial cells (LECs). We questioned whether dysregulated expression of these transcription factors contributes to disease pathogenesis and found that LEC-specific deletion of Hif-2α exacerbated lymphedema pathology. Even without lymphatic vascular injury, the loss of LEC-specific Hif-2α caused anatomic pathology and a functional decline in fetal and adult mice. These findings suggest that HIF-2α is an important mediator of lymphatic health. HIF-2α promoted protective phosphorylated TIE2 (p-TIE2) signaling in LECs, a process also replicated by upregulating TIE2 signaling through adenovirus-mediated angiopoietin-1 (Angpt1) gene therapy. Our study suggests that HIF-2α normally promotes healthy lymphatic homeostasis and raises the exciting possibility that restoring HIF-2α pathways in lymphedema could mitigate long-term pathology and disability.
Xinguo Jiang, Wen Tian, Eric J. Granucci, Allen B. Tu, Dongeon Kim, Petra Dahms, Shravani Pasupneti, Gongyong Peng, Yesl Kim, Amber H. Lim, F. Hernan Espinoza, Matthew Cribb, J. Brandon Dixon, Stanley G. Rockson, Gregg L. Semenza, Mark R. Nicolls
Tissue factor (TF) is the primary initiator of blood coagulation in vivo and the only blood coagulation factor for which a human genetic defect has not been described. As there are no routine clinical assays that capture the contribution of endogenous TF to coagulation initiation, the extent to which reduced TF activity contributes to unexplained bleeding is unknown. Using whole genome sequencing, we identified a heterozygous frameshift variant (p.Ser117HisfsTer10) in F3, the gene encoding TF, causing premature termination of TF ("TFshort") in a woman with unexplained bleeding. Routine hematological laboratory evaluation of the proposita was normal. CRISPR-edited human induced pluripotent stem cells recapitulating the variant were differentiated into vascular smooth muscle and endothelial cells that demonstrated haploinsufficiency of TF. The variant F3 transcript is eliminated by nonsense-mediated decay. Neither overexpression nor addition of exogenous recombinant TFshort inhibited factor Xa or thrombin generation, excluding a dominant negative mechanism. F3+/- mice provide an animal model of TF haploinsufficiency and exhibited prolonged bleeding times, impaired thrombus formation, and reduced survival following major injury. Heterozygous TF deficiency is present in at least 1 in 25,000 individuals and could limit coagulation initiation in undiagnosed individuals with abnormal bleeding but a normal routine laboratory evaluation.
Sol Schulman, Emale El-Darzi, Mary HC Florido, Max Friesen, Glenn Merrill-Skoloff, Marisa A. Brake, Calvin R. Schuster, Lin Lin, Randal J. Westrick, Chad A. Cowan, Robert Flaumenhaft, NIHR BioResource, Willem H. Ouwehand, Kathelijne Peerlinck, Kathleen Freson, Ernest Turro, Bruce Furie
Aging is associated with a high prevalence of hypertension due to elevated susceptibility of BP to dietary salt, but its mechanism is unknown. Serum levels of Klotho, an anti-aging factor, decline with age. We found that high salt (HS) increased BP in aged mice and young heterozygous Klotho-knockout mice and was associated with increased vascular expression of Wnt5a and p-MYPT1, which indicate RhoA activity. Not only the Wnt inhibitor LGK974 and the Wnt5a antagonist Box5 but Klotho supplementation inhibits HS-induced BP elevation, similarly to the Rho kinase inhibitor fasudil, associated with reduced p-MYPT1 expression in both groups of mice. In cultured vascular smooth muscle cells, Wnt5a and angiotensin II (Ang II) increased p-MYPT1 expression but knockdown of Wnt5a with siRNA abolished Ang II–induced upregulation of p-MYPT1, indicating that Wnt5a is indispensable for Ang II–induced Rho/ROCK activation. Notably, Klotho inhibited Wnt5a- and Ang II–induced upregulation of p-MYPT1. Consistently, Klotho supplementation ameliorated HS-induced augmentation of reduced renal blood flow (RBF) response to intra-arterial infusion of Ang II and the thromboxane A2 analog U46619, which activated RhoA in both groups of mice and were associated with the inhibition of BP elevation, suggesting that abnormal response of RBF to Ang II contributes to HS-induced BP elevation. Thus, Klotho deficiency underlies aging-associated salt-sensitive hypertension through vascular non-canonical Wnt5a/RhoA activation.
Wakako Kawarazaki, Risuke Mizuno, Mitsuhiro Nishimoto, Nobuhiro Ayuzawa, Daigoro Hirohama, Kohei Ueda, Fumiko Kawakami-Mori, Shigeyoshi Oba, Takeshi Marumo, Toshiro Fujita
Diabetic patients develop endothelial dysfunction shortly after diabetes onset that progresses to vascular disease underlying the majority of diabetes associated comorbidities. Increased lipid peroxidation, mitochondrial calcium overload and mitochondrial dysfunction are characteristics of dysfunctional endothelial cells in diabetic patients. We here identified that targeting the lipid peroxidation product 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE) induced activation of the intracellularly located cation channel transient receptor potential vanilloid 1 (TRPV1) in endothelial cells is a means to causally control early stage vascular disease in type I diabetic mice. Mice with an inducible, endothelial specific 12/15 lipoxygenase (12/15Lo) knock out were similarly protected from type I diabetes induced endothelial dysfunction and impaired vascular regeneration following arterial injury as TRPV1 knock out mice. Both 12(S)-HETE in concentrations found in diabetic patients and TRPV1 agonists triggered mitochondrial calcium influx and mitochondrial dysfunction in endothelial cells and 12(S)-HETE effects were absent in endothelial cells from TRPV1 knock out mice. As a therapeutic consequence, we found that a peptide targeting 12(S)-HETE induced TRPV1 interaction at the TRPV1 TRP box ameliorated diabetes-induced endothelial dysfunction and augmented vascular regeneration in diabetic mice. Our findings suggest that pharmacological targeting of increased endothelial lipid peroxidation can attenuate diabetes induced comorbidities related to vascular disease.
Mandy Otto, Clarissa Bucher, Wantao Liu, Melanie Müller, Tobias Schmidt, Marina Kardell, Marvin Noel Driessen, Jan Rossaint, Eric R. Gross, Nana-Maria Wagner
The baroreceptor reflex is a powerful neural feedback that regulates arterial pressure (AP). Mechanosensitive channels transduce pulsatile AP to electrical signals in baroreceptors. Here we show that tentonin 3 (TTN3/TMEM150C), a cation channel activated by mechanical strokes, is essential for detecting AP changes in the aortic arch. TTN3 was expressed in nerve terminals in the aortic arch and nodose ganglion (NG) neurons. Genetic ablation of Ttn3 induced ambient hypertension, tachycardia, AP fluctuations, and impaired baroreflex sensitivity. Chemogenetic silencing or activation of Ttn3+ neurons in the NG resulted in an increase in AP and heart rate, or vice versa. More important, overexpression of Ttn3 in the NG of Ttn3–/– mice reversed the cardiovascular changes observed in Ttn3–/– mice. We conclude that TTN3 is a molecular component contributing to the sensing of dynamic AP changes in baroreceptors.
Huan-Jun Lu, Thien-Luan Nguyen, Gyu-Sang Hong, Sungmin Pak, Hyesu Kim, Hyungsup Kim, Dong-Yoon Kim, Sung-Yon Kim, Yiming Shen, Pan Dong Ryu, Mi-Ock Lee, Uhtaek Oh
While Canakinumab Anti-Inflammatory Thrombosis Outcomes Study (CANTOS) established the role of treating inflammation in atherosclerosis, our understanding of endothelial activation at atherosclerosis-prone sites remains limited. Disturbed flow at atheroprone regions primes plaque inflammation by enhancing endothelial NF-κB signaling. Herein, we demonstrate a role for the Nck adaptor proteins in disturbed flow-induced endothelial activation. Although highly similar, only Nck1 deletion, but not Nck2 deletion, limited flow-induced NF-κB activation and proinflammatory gene expression. Nck1 knockout mice showed reduced endothelial activation and inflammation in both models of disturbed flow and high fat diet-induced atherosclerosis, whereas Nck2 deletion did not. Bone marrow chimeras confirmed that vascular Nck1, but not hematopoietic Nck1, mediated this effect. Domain swap experiments and point mutations identified the Nck1 SH2 domain and the first SH3 domain as critical for flow-induced endothelial activation. We further characterized Nck1’s proinflammatory role by identifying interleukin-1 type I receptor kinase-1 (IRAK-1) as a Nck1-selective binding partner, demonstrating IRAK-1 activation by disturbed flow required Nck1 in vitro and in vivo, showing endothelial Nck1 and IRAK-1 staining in early human atherosclerosis, and demonstrating that disturbed flow-induced endothelial activation required IRAK-1. Taken together, our data reveal a hitherto unknown link between Nck1 and IRAK-1 in atherogenic inflammation.
Mabruka Alfaidi, Christina H. Acosta, Dongdong Wang, James G. Traylor, A. Wayne Orr
Diabetes, obesity and Alzheimer’s disease (AD) are associated with vascular complications and impaired nitric oxide (NO) production. Furthermore, increased β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1), APP and β-amyloid (Aβ) are linked with vascular disease development and raised BACE1 and Aβ accompany hyperglycemia and hyperlipidemia. However, the causal relationship between obesity and diabetes, raised Aβ and vascular dysfunction is unclear. We report that diet-induced obesity (DIO) in mice raised plasma and vascular Aβ42 that correlated with decreased NO bioavailability, endothelial dysfunction and raised blood pressure. Genetic or pharmacological reduction of BACE1 activity and Aβ42 prevented and reversed, respectively, these outcomes. In contrast, expression of human mutant APP in mice or Aβ42 infusion into control diet-fed mice to mimic obese levels impaired NO production, vascular relaxation and raised blood pressure. In humans, raised plasma Aβ42 correlated with diabetes and endothelial dysfunction. Mechanistically, higher Aβ42 reduced endothelial NO synthase (eNOS), cyclic GMP and protein kinase G (PKG) activity independently of diet whereas endothelin-1 was increased by diet and Aβ42. Lowering Aβ42 reversed the DIO deficit in the eNOS-cGMP-PKG pathway and decreased endothelin-1. Our findings suggest that BACE1 inhibitors may have therapeutic value in the treatment of vascular disease associated with diabetes.
Paul J. Meakin, Bethany M. Coull, Zofia Tuharska, Christopher McCaffery, Ioannis Akoumianakis, Charalambos Antoniades, Jane Brown, Kathryn J. Griffin, Fiona Platt, Claire H. Ozber, Nadira Y. Yuldasheva, Natallia Makava, Anna Skromna, Alan Russell Prescott, Alison D. McNeilly, Moneeza K. Siddiqui, Colin Neil Alexander Palmer, Faisel Khan, Michael LJ Ashford
Several missense mutations in the orphan transporter FLVCR2 have been reported in Fowler syndrome. Affected subjects exhibit signs of severe neurological defects. We identified the mouse ortholog Mfsd7c as a gene, which is expressed in the blood brain barrier. Here, we report the characterizations of Mfsd7c knockout (KO) mice and compare it to phenotypic findings in humans with bi-allelic FLVCR2 mutations. Global KO of Mfsd7c in mice resulted in late gestation lethality, likely due to central nervous system (CNS) phenotypes. We found that the angiogenic growth of CNS blood vessels in the brain of Mfsd7c KO embryos was inhibited in cortical ventricular zones and ganglionic eminences. Vascular tips were dilated and fused resulting in glomeruloid vessels. Nonetheless, CNS blood vessels were intact without haemorrhage. Both embryos and humans with bi-allelic FLVCR2 mutations exhibited reduced cerebral cortical layers, enlargement of the cerebral ventricles, and microcephaly. Transcriptomic analysis of Mfsd7c knockout (KO) embryonic brains revealed upregulation of genes involved in glycolysis and angiogenesis. The Mfsd7c KO brain exhibited hypoxia and neuronal cell death. Our results indicate MFSD7c is required for the normal growth of CNS blood vessels and ablation of this gene results in microcephaly-associated vasculopathy in mice and humans.
Pazhanichamy Kalailingam, Kai Qi Wang, Xiu Ru Toh, Toan Q. Nguyen, Madhuvanthi Chandrakanthan, Zafrul Hasan, Clair Habib, Aharon Schif, Francesca Clementina Radio, Bruno Dallapiccola, Karin Weiss, Long N. Nguyen
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