Transgenic mice over-expressing ET-1 in the endothelial cells develop systemic hypertension with altered vascular reactivity

Endothelial and Vascular Smooth Muscle Dysfunction in Hypertension

The development of essential hypertension involves several factors. Vascular dysfunction, characterized by endothelial dysfunction, low-grade inflammation and structural remodeling, plays an important role in the initiation and maintenance of essential hypertension. Although the mechanistic pathways by which essential hypertension develops are poorly understood, several pharmacological classes available on the clinical settings improve blood pressure by interfering in the cardiac output and/or vascular function. This review is divided in two major sections. The first section depicts the major molecular pathways as renin angiotensin aldosterone system (RAAS), endothelin, nitric oxide signalling pathway and oxidative stress in the development of vascular dysfunction. The second section describes the role of some pharmacological classes such as i) RAAS inhibitors, ii) dual angiotensin receptor-neprilysin inhibitors, iii) endothelin-1 receptor antagonists, iv) soluble guanylate cyclase modulators, v) phosphodiesterase type 5 inhibitors and vi) sodium-glucose cotransporter 2 inhibitors in the context of hypertension. Some classes are already approved in the treatment of hypertension, but others are not yet approved. However, due to their potential benefits these classes were included.

Endothelial Cells and the Cerebral Circulation

Endothelial cells form the innermost layer of all blood vessels and are the only vascular component that remains throughout all vascular segments. The cerebral vasculature has several unique properties not found in the peripheral circulation; this requires that the cerebral endothelium be considered as a unique entity. Cerebral endothelial cells perform several functions vital for brain health. The cerebral vasculature is responsible for protecting the brain from external threats carried in the blood. The endothelial cells are central to this requirement as they form the basis of the blood-brain barrier. The endothelium also regulates fibrinolysis, thrombosis, platelet activation, vascular permeability, metabolism, catabolism, inflammation, and white cell trafficking. Endothelial cells regulate the changes in vascular structure caused by angiogenesis and artery remodeling. Further, the endothelium contributes to vascular tone, allowing proper perfusion of the brain which has high energy demands and no energy stores. In this article, we discuss the basic anatomy and physiology of the cerebral endothelium. Where appropriate, we discuss the detrimental effects of high blood pressure on the cerebral endothelium and the contribution of cerebrovascular disease endothelial dysfunction and dementia. © 2022 American Physiological Society. Compr Physiol 12:3449-3508, 2022.

Berberine alleviates monosodium glutamate induced postnatal metabolic disorders associated vascular endothelial dysfunction in newborn rats: possible role of matrix metalloproteinase-1

Excessive food additives Monosodium glutamate (MSG) results in metabolic disorders with increased Cardiovascular diseases CVD. We aimed to emphasise berberine (BBR) effect on MSG induced metabolic syndrome (MetS) and its associated endothelial dysfunction. Newborn rats were divided into control group, MSG group (4 mg/g) each other day for the first 14 days of life and MSG + BBR group that was given MSG then BBR in dose 150 mg/kg/day for 6 weeks. Body weight, food intake, systolic blood pressure, biochemical metabolic and oxidative stress markers were evaluated. Aortic tissue homogenate Endothelin -1 (ET-1) and matrix metalloproteinase -1 (MMP-1) assessment, in addition to histological and EM examination were done. Newborn rats MSG exposure results in typical adult life MetS and oxidative stress with significant increase in ET-1 and MMP-1with aortic vasculopathy. BBR significantly improved all the disturbed parameters; suppress increased body weight (BW), food intake (FI) and partly improved the aortic vasculopathy lesions, holding a promise for BBR as a defending agent against MSG metabolic and vascular disorders.HIGH LIGHT MSGMSG is frequently consumed as a flavour enhancer especially between children and adolescentExcessive utilisation MSG is associated MS with vascular endothelial dysfunctionMMP-1 may be involved in atherosclerotic plaque formationBBR has beneficial outcome for metabolic disorders induced by MSG among newly born ratsBBR has a role in management vascular inflammation and remodelling.

The role of endothelin and RAS/ERK signaling in immunopathogenesis-related fibrosis in patients with systemic sclerosis: an updated review with therapeutic implications

Systemic sclerosis (SSc) is a disease of connective tissue with high rate of morbidity and mortality highlighted by extreme fibrosis affecting various organs such as the dermis, lungs, and heart. Until now, there is no specific cure for the fibrosis occurred in SSc disease. The SSc pathogenesis is yet unknown, but transforming growth factor beta (TGF-β), endothelin-1 (ET-1), and Ras-ERK1/2 cascade are the main factors contributing to the tissue fibrosis through extracellular matrix (ECM) accumulation. Several studies have hallmarked the association of ET-1 with or without TGF-β and Ras-ERK1/2 signaling in the development of SSc disease, vasculopathy, and fibrosis of the dermis, lungs, and several organs. Accordingly, different clinical and experimental studies have indicated the potential therapeutic role of ET-1 and Ras antagonists in these situations in SSc. In addition, ET-1 and connective tissue growth factor (CTGF) as a cofactor of the TGF-β cascade play a substantial initiative role in inducing fibrosis. Once initiated, TGF-β alone or in combination with ET-1 and CTGF can activate several kinase proteins such as the Ras-ERK1/2 pathway that serve as the fundamental factor for developing fibrosis. Furthermore, Salirasib is a synthetic small molecule that is able to inhibit all Ras forms. Therefore, it can be used as a potent therapeutic factor for fibrotic disorders. So, this review discusses the role of TGF-β/ET-1/Ras signaling and their involvement in SSc pathogenesis, particularly in its fibrotic situation.

Chronic social defeat stress causes retinal vascular dysfunction

PURPOSE

The roles of vascular dysfunction and chronic stress have been extensively discussed in the pathophysiology of glaucoma. Our aim was to test whether chronic stress causes retinal vascular dysfunction and therewith induces retinal ganglion cells (RGCs) loss.

METHODS

Twelve mice underwent chronic social defeat (CSD) stress, while 12 mice received control treatment only. Intraocular pressure (IOP) was measured with a rebound tonometer. Blood plasma corticosterone concentration and adrenal gland weight were used to assess stress levels. Brn-3a staining in retinas and PPD staining in optic nerve cross sections were conducted to assess the survival of RGCs and axons respectively. The ET-1 and α-SMA levels were determined in retina. Retinal vascular autoregulation, functional response to various vasoactive agents and vascular mechanics were measured using video microscopy.

RESULTS

No significant difference in IOP levels was observed during and after CSD between CSD mice and controls. CSD stress caused hypercortisolemia 2 days post-CSD. However, increased corticosterone levels went back to normal 8 months after CSD. CSD-exposed mice developed adrenal hyperplasia 3 days post-CSD, which was normalized by 8 months. RGC and axon survival were similar between CSD mice and controls. However, CSD stress caused irreversible, impaired autoregulation and vascular dysfunction of retinal arterioles in CSD mice. In addition, impaired maximal dilator capacity of retinal arterioles was observed 8 months post-CSD rather than 3 days post-CSD. Remarkably, ET-1 levels were increased 3 days post-CSD while α-SMA levels were decreased 8 months post-CSD.

CONCLUSIONS

We found that CSD stress does not cause IOP elevation, nor loss of RGCs and their axons. However, it strikingly causes irreversible impaired autoregulation and endothelial function in murine retinal arterioles. In addition, CSD changed vascular mechanics on a long-term basis. Increased ET-1 levels and loss of pericytes in retina vessels may involve in this process.

The Causal Relationship between Endothelin-1 and Hypertension: Focusing on Endothelial Dysfunction, Arterial Stiffness, Vascular Remodeling, and Blood Pressure Regulation

Hypertension (HTN) is one of the most prevalent diseases worldwide and is among the most important risk factors for cardiovascular and cerebrovascular complications. It is currently thought to be the result of disturbances in a number of neural, renal, hormonal, and vascular mechanisms regulating blood pressure (BP), so crucial importance is given to the imbalance of a number of vasoactive factors produced by the endothelium. Decreased nitric oxide production and increased production of endothelin-1 (ET-1) in the vascular wall may promote oxidative stress and low-grade inflammation, with the development of endothelial dysfunction (ED) and increased vasoconstrictor activity. Increased ET-1 production can contribute to arterial aging and the development of atherosclerotic changes, which are associated with increased arterial stiffness and manifestation of isolated systolic HTN. In addition, ET-1 is involved in the complex regulation of BP through synergistic interactions with angiotensin II, regulates the production of catecholamines and sympathetic activity, affects renal hemodynamics and water–salt balance, and regulates baroreceptor activity and myocardial contractility. This review focuses on the relationship between ET-1 and HTN and in particular on the key role of ET-1 in the pathogenesis of ED, arterial structural changes, and impaired vascular regulation of BP. The information presented includes basic concepts on the role of ET-1 in the pathogenesis of HTN without going into detailed analyses, which allows it to be used by a wide range of specialists. Also, the main pathological processes and mechanisms are richly illustrated for better understanding.

Endothelin: 30 Years From Discovery to Therapy

Discovered in 1987 as a potent endothelial cell-derived vasoconstrictor peptide, endothelin-1 (ET-1), the predominant member of the endothelin peptide family, is now recognized as a multifunctional peptide with cytokine-like activity contributing to almost all aspects of physiology and cell function. More than 30 000 scientific articles on endothelin were published over the past 3 decades, leading to the development and subsequent regulatory approval of a new class of therapeutics-the endothelin receptor antagonists (ERAs). This article reviews the history of the discovery of endothelin and its role in genetics, physiology, and disease. Here, we summarize the main clinical trials using ERAs and discuss the role of endothelin in cardiovascular diseases such as arterial hypertension, preecclampsia, coronary atherosclerosis, myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) caused by spontaneous coronary artery dissection (SCAD), Takotsubo syndrome, and heart failure. We also discuss how endothelins contributes to diabetic kidney disease and focal segmental glomerulosclerosis, pulmonary arterial hypertension, as well as cancer, immune disorders, and allograft rejection (which all involve ET_A autoantibodies), and neurological diseases. The application of ERAs, dual endothelin receptor/angiotensin receptor antagonists (DARAs), selective ET_B agonists, novel biologics such as receptor-targeting antibodies, or immunization against ET_A receptors holds the potential to slow the progression or even reverse chronic noncommunicable diseases. Future clinical studies will show whether targeting endothelin receptors can prevent or reduce disability from disease and improve clinical outcome, quality of life, and survival in patients.

Chronic Elevation of Endothelin-1 Alone May Not Be Sufficient to Impair Endothelium-Dependent Relaxation

Endothelin-1 (ET-1) is a powerful vasoconstrictor peptide considered to be causally implicated in hypertension and the development of cardiovascular disease. Increased ET-1 is commonly associated with reduced NO bioavailability and impaired vascular function; however, whether chronic elevation of ET-1 directly impairs endothelium-dependent relaxation (EDR) remains elusive. Herein, we report that (1) prolonged ET-1 exposure (ie, 48 hours) of naive mouse aortas or cultured endothelial cells did not impair EDR or reduce eNOS (endothelial NO synthase) activity, respectively (P>0.05); (2) mice with endothelial cell-specific ET-1 overexpression did not exhibit impaired EDR or reduced eNOS activity (P>0.05); (3) chronic (8 weeks) pharmacological blockade of ET-1 receptors in obese/hyperlipidemic mice did not improve aortic EDR or increase eNOS activity (P>0.05); and (4) vascular and plasma ET-1 did not inversely correlate with EDR in resistance arteries isolated from human subjects with a wide range of ET-1 levels (r=0.0037 and r=-0.1258, respectively). Furthermore, we report that prolonged ET-1 exposure downregulated vascular UCP-1 (uncoupling protein-1; P<0.05), which may contribute to the preservation of EDR in conditions characterized by hyperendothelinemia. Collectively, our findings demonstrate that chronic elevation of ET-1 alone may not be sufficient to impair EDR.

Overproduction of endothelin-1 impairs glucose tolerance but does not promote visceral adipose tissue inflammation or limit metabolic adaptations to exercise

Endothelin-1 (ET-1) is a potent vasoconstrictor and proinflammatory peptide that is upregulated in obesity. Herein, we tested the hypothesis that ET-1 signaling promotes visceral adipose tissue (AT) inflammation and disrupts glucose homeostasis. We also tested if reduced ET-1 is a required mechanism by which exercise ameliorates AT inflammation and improves glycemic control in obesity. We found that 1) diet-induced obesity, AT inflammation, and glycemic dysregulation were not accompanied by significantly increased levels of ET-1 in AT or circulation in wild-type mice and that endothelial overexpression of ET-1 and consequently increased ET-1 levels did not cause AT inflammation yet impaired glucose tolerance; 2) reduced AT inflammation and improved glucose tolerance with voluntary wheel running was not associated with decreased levels of ET-1 in AT or circulation in obese mice nor did endothelial overexpression of ET-1 impede such exercise-induced metabolic adaptations; 3) chronic pharmacological blockade of ET-1 receptors did not suppress AT inflammation in obese mice but improved glucose tolerance; and 4) in a cohort of human subjects with a wide range of body mass indexes, ET-1 levels in AT, or circulation were not correlated with markers of inflammation in AT. In aggregate, we conclude that ET-1 signaling is not implicated in the development of visceral AT inflammation but promotes glucose intolerance, thus representing an important therapeutic target for glycemic dysregulation in conditions characterized by hyperendothelinemia. Furthermore, we show that the salutary effects of exercise on AT and systemic metabolic function are not contingent on the suppression of ET-1 signaling.

Evaluation of the circulating MicroRNA-495 and Stat3 as prognostic and predictive biomarkers for lower extremity deep venous thrombosis

This study aims to elucidate the prognostic and predictive biomarker of miR-495 and Stat3 in peripheral blood in relation to lower extremity deep venous thrombosis (DVT). Patients with lower limb fractures were assigned into case and control groups. Rats were allocated into blank (normal rats), sham (normal rats), DVT, miR-495 mimic, miR-495 inhibitor, over-Stat3, and si-Stat3 groups. ELISA was used to detect levels of prothrombin time (PT), endothelin-1 (ET-1), Human Fibrinogen (FIB), D-Dimer, blood coagulation factors V and VIII, tissue type plasminogen activator (t-PA), platelet activating factor (PAF), protein C and Stat3. qRT-PCR was employed for the evaluation of the expressions of miR-495 and Stat3, while receiver operating characteristic (ROC) curve was constructed to assess the predictive value of miR-495 and Stat3 as well as the treatment outcomes of patients with lower limb fractures. Logistic regression analyses were conducted in order to correlate indexes and lower extremity DVT. miR-495 overexpression, t-PA, PAF, and protein C were confirmed to be protective factors, while Stat3 overexpression, PT, ET-1, FIB, D-Dimer, blood coagulation factor V, and VIII were all ultimately considered to be risk factors of lower extremity DVT. Stat3 was confirmed to be the target gene of miR-495. Compared with the blank group, the length and weight of the thrombus as well as the ratio between length and weight, mRNA and protein expression of Stat3 were reduced in the miR-495 mimic and si-Stat3 groups. Our findings suggest that through the suppression of Stat3 expression, miR-495 prohibits lower extremity DVT in peripheral blood.

TRAF3IP2 mediates high glucose-induced endothelin-1 production as well as endothelin-1-induced inflammation in endothelial cells

Hyperglycemia-induced production of endothelin (ET)-1 is a hallmark of endothelial dysfunction in diabetes. Although the detrimental vascular effects of increased ET-1 are well known, the molecular mechanisms regulating endothelial synthesis of ET-1 in the setting of diabetes remain largely unidentified. Here, we show that adapter molecule TRAF3 interacting protein 2 (TRAF3IP2) mediates high glucose-induced ET-1 production in endothelial cells and ET-1-mediated endothelial cell inflammation. Specifically, we found that high glucose upregulated TRAF3IP2 in human aortic endothelial cells, which subsequently led to activation of JNK and IKKβ. shRNA-mediated silencing of TRAF3IP2, JNK1, or IKKβ abrogated high-glucose-induced ET-converting enzyme 1 expression and ET-1 production. Likewise, overexpression of TRAF3IP2, in the absence of high glucose, led to activation of JNK and IKKβ as well as increased ET-1 production. Furthermore, ET-1 transcriptionally upregulated TRAF3IP2, and this upregulation was prevented by pharmacological inhibition of ET-1 receptor B using BQ-788, or inhibition of NADPH oxidase-derived reactive oxygen species using gp91ds-tat and GKT137831. Notably, we found that knockdown of TRAF3IP2 abolished ET-1-induced proinflammatory and adhesion molecule (IL-1β, TNF-α, monocyte chemoattractant protein 1, ICAM-1, VCAM-1, and E-selectin) expression and monocyte adhesion to endothelial cells. Finally, we report that TRAF3IP2 is upregulated and colocalized with CD31, an endothelial marker, in the aorta of diabetic mice. Collectively, findings from the present study identify endothelial TRAF3IP2 as a potential new therapeutic target to suppress ET-1 production and associated vascular complications in diabetes. NEW & NOTEWORTHY This study provides the first evidence that the adapter molecule TRAF3 interacting protein 2 mediates high glucose-induced production of endothelin-1 by endothelial cells as well as endothelin-1-mediated endothelial cell inflammation. The findings presented herein suggest that TRAF3 interacting protein 2 may be an important therapeutic target in diabetic vasculopathy characterized by excess endothelin-1 production.

Endothelial overexpression of endothelin-1 modulates aortic, carotid, iliac and renal arterial responses in obese mice

Endothelin-1 (ET-1) is essential for mammalian development and life, but it has also been implicated in increased cardiovascular risk under pathophysiological conditions. The aim of this study was to determine the impact of endothelial overexpression of the prepro-endothelin-1 gene on endothelium-dependent and endothelium-independent responses in the conduit and renal arteries of lean and obese mice. Obesity was induced by high-fat-diet (HFD) consumption in mice with Tie-1 promoter-driven, endothelium-specific overexpression of the prepro-endothelin-1 gene (TET^het) and in wild-type (WT) littermates on a C57BL/6N background. Isometric tension was measured in rings (with endothelium) of the aorta (A), carotid (CA) and iliac (IA) arteries as well as the main (MRA) and segmental renal (SRA) arteries; all experiments were conducted in the absence or presence of L-NAME and/or the COX inhibitor meclofenamate. The release of prostacyclin and thromboxane A2 was measured by ELISA. In the MRA, TET^het per se increased contractions to endothelin-1, but the response was decreased in SRA in response to serotonin; there were also improved relaxations to acetylcholine but not insulin in the SRA in the presence of L-NAME. HFD per se augmented the contractions to endothelin-1 (MRA) and to the thromboxane prostanoid (TP) receptor agonist U46619 (CA, MRA) as well as facilitated relaxations to isoproterenol (A). The combination of HFD and TET^het overexpression increased the contractions of MRA and SRA to vasoconstrictors but not in the presence of meclofenamate; this combination also augmented further relaxations to isoproterenol in the A. Contractions to endothelin-1 in the IA were prevented by endothelin-A receptor antagonist BQ-123 but only attenuated in obese mice by BQ-788. The COX-1 inhibitor FR122047 abolished the contractions of CA to acetylcholine. The release of prostacyclin during the latter condition was augmented in samples from obese TET^het mice and abolished by FR122047. These findings suggest that endothelial TET^het overexpression in lean animals has minimal effects on vascular responsiveness. However, if comorbid with obesity, endothelin-1-modulated, prostanoid-mediated renal arterial dysfunction becomes apparent.

Endothelial dysfunction and vascular disease - a 30th anniversary update

The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best-characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDH-mediated responses). As regards the latter, hydrogen peroxide (H₂ O₂ ) now appears to play a dominant role. Endothelium-dependent relaxations involve both pertussis toxin-sensitive G_i (e.g. responses to α₂ -adrenergic agonists, serotonin, and thrombin) and pertussis toxin-insensitive G_q (e.g. adenosine diphosphate and bradykinin) coupling proteins. New stimulators (e.g. insulin, adiponectin) of the release of EDRFs have emerged. In recent years, evidence has also accumulated, confirming that the release of NO by the endothelial cell can chronically be upregulated (e.g. by oestrogens, exercise and dietary factors) and downregulated (e.g. oxidative stress, smoking, pollution and oxidized low-density lipoproteins) and that it is reduced with ageing and in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively lose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and EDH, in particular those due to H₂ O₂ ), endothelial cells also can evoke contraction of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factors. Recent evidence confirms that most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells and that prostacyclin plays a key role in such responses. Endothelium-dependent contractions are exacerbated when the production of nitric oxide is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive and diabetic patients. In addition, recent data confirm that the release of endothelin-1 can contribute to endothelial dysfunction and that the peptide appears to be an important contributor to vascular dysfunction. Finally, it has become clear that nitric oxide itself, under certain conditions (e.g. hypoxia), can cause biased activation of soluble guanylyl cyclase leading to the production of cyclic inosine monophosphate (cIMP) rather than cGMP and hence causes contraction rather than relaxation of the underlying vascular smooth muscle.

Gene silencing of endothelial von Willebrand Factor attenuates angiotensin II-induced endothelin-1 expression in porcine aortic endothelial cells

Expression of endothelin (ET)-1 is increased in endothelial cells exposed to angiotensin II (Ang II), leading to endothelial dysfunction and cardiovascular disorders. Since von Willebrand Factor (vWF) blockade improves endothelial function in coronary patients, we hypothesized that targeting endothelial vWF with short interference RNA (siRNA) prevents Ang II-induced ET-1 upregulation. Nearly 65 ± 2% silencing of vWF in porcine aortic endothelial cells (PAOECs) was achieved with vWF-specific siRNA without affecting cell viability and growth. While showing ET-1 similar to wild type cells at rest, vWF-silenced cells did not present ET-1 upregulation during exposure to Ang II (100 nM/24 h), preserving levels of endothelial nitric oxide synthase activity similar to wild type. vWF silencing prevented AngII-induced increase in nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activity and superoxide anion (O2-) levels, known triggers of ET-1 expression. Moreover, no increase in O2- or ET-1 levels was found in silenced cells treated with AngII or NOX-agonist phorbol ester (PMA 5 nM/48 h). Finally, vWF was required for overexpression of NOX4 and NOX2 in response to AngII and PMA. In conclusion, endothelial vWF knockdown prevented Ang II-induced ET-1 upregulation through attenuation of NOX-mediated O2- production. Our findings reveal a new role of vWF in preventing of Ang II-induced endothelial dysfunction.

A Single-Nucleotide Polymorphism in 3'-Untranslated Region of Endothelin-1 Reduces Risk of Dementia After Ischemic Stroke

BACKGROUND Ischemic stroke is widely recognized as a major health problem and social burden worldwide, and it usually leads to dementia. In this study, we aimed to better understand the pathogenesis in the development of dementia following ischemic stroke. MATERIAL AND METHODS We exploited miRNA database to search for the target for miR-125a and validated the found target using luciferase assay. Further, we performed real-time PCR and Western blot analysis to examine the expression of miR-125a and its target in the tissue samples. In addition, a polymorphism was genotyped and its association with post-stroke dementia was analyzed. RESULTS We identified enthothelin-1 (ET-1) as a target of miR-125a, and this relationship was validated using luciferase assay. Furthermore, transfection of miR-125a inhibitor substantially upregulated the expression of ET-1, while miR-125a and ET-1 siRNA caused downregulation of ET-1 in endothelial cells. In addition, we found that a polymorphism (rs12976445) interferes with the expression of miR-125a, which in turn caused an increase in the expression of ET-1 in human endothelial cells. Logistic regression analysis showed that rs12976445 is significantly associated with the risk of dementia after ischemic stroke. CONCLUSIONS Our study demonstrated the pathogenesis mechanism during the development of dementia after ischemic stroke by investigating the relationship between miR-125a and its target ET-1, promising a potential pathological solution for post-stroke dementia in the future.

A Mediterranean diet supplemented with extra virgin olive oil or nuts improves endothelial markers involved in blood pressure control in hypertensive women

PURPOSE

Serum nitric oxide (NO) reduction and increased endothelin-1 (ET-1) play a pivotal role in endothelial dysfunction and hypertension. Considering that traditional Mediterranean diet (TMD) reduces blood pressure (BP), the aim of this study was to analyze whether TMD induced changes on endothelial physiology elements such as NO, ET-1 and ET-1 receptors which are involved in BP control.

METHODS

Non-smoking women with moderate hypertension were submitted for 1 year to interventions promoting adherence to the TMD, one supplemented with extra virgin olive oil (EVOO) and the other with nuts versus a control low-fat diet (30 participants/group). BP, NO, ET-1 and related gene expression as well as oxidative stress biomarkers were measured.

RESULTS

Serum NO and systolic BP (SBP) or diastolic BP (DBP) were negatively associated at baseline, as well as between NO and ET-1. Our findings also showed a DBP reduction with both interventions. A negative correlation was observed between changes in NO metabolites concentration and SBP or DBP after the intervention with TMD + EVOO (p = 0.033 and p = 0.044, respectively). SBP reduction was related to an impairment of serum ET-1 concentrations after the intervention with TMD + nuts (p = 0.008). We also observed changes in eNOS, caveolin 2 and ET-1 receptors gene expression which are related to NO metabolites levels and BP.

CONCLUSIONS

The changes in NO and ET-1 as well as ET-1 receptors gene expression explain, at least partially, the effect of EVOO or nuts on lowering BP among hypertensive women.

The emerging role of endothelin-1 in the pathogenesis of subchondral bone disturbance and osteoarthritis

Mounting evidence suggests reconceptualizing osteoarthritis (OA) as an inflammatory disorder. Trauma and obesity, the common risk factors of OA, could trigger the local or systemic inflammatory cytokines cascade. Inflammatory bone loss has been well documented; yet it remains largely unknown about the link between the inflammation and hypertrophic changes of subchondral bone seen in OA, such as osteophytosis and sclerosis. Amid a cohort of inflammatory cytokines, endothelin-1 (ET-1) could stimulate the osteoblast-mediated bone formation in both physiological (postnatal growth of trabecular bone) and pathological conditions (bone metastasis of prostate or breast cancer). Also, ET-1 is known as a mitogen and contributes to fibrosis in various organs, e.g., skin, liver, lung, kidney heart and etc., as a result of inflammatory or metabolic disorders. Subchondral bone sclerosis shared the similarity with fibrosis in terms of the overproduction of collagen type I. We postulated that ET-1 might have a hand in the subchondral bone sclerosis of OA. Meanwhile, ET-1 was also able to stimulate the production of matrix metalloproteinase (MMP)-1 and 13 by articular chondrocytes and synoviocytes, by which it might trigger the enzymatic degradation of articular cartilage. Taken together, ET-1 signaling may play a role in destruction of bone-cartilage unit in the pathogenesis of OA; it warrants further investigations to potentiate ET-1 as a novel diagnostic biomarker and therapeutic target for rescue of OA.

Cre recombinase-regulated Endothelin1 transgenic mouse lines: novel tools for analysis of embryonic and adult disorders

Endothelin-1 (EDN1) influences both craniofacial and cardiovascular development and a number of adult physiological conditions by binding to one or both of the known endothelin receptors, thus initiating multiple signaling cascades. Animal models containing both conventional and conditional loss of the Edn1 gene have been used to dissect EDN1 function in both embryos and adults. However, while transgenic Edn1 over-expression or targeted genomic insertion of Edn1 has been performed to understand how elevated levels of Edn1 result in or exacerbate disease states, an animal model in which Edn1 over-expression can be achieved in a spatiotemporal-specific manner has not been reported. Here we describe the creation of Edn1 conditional over-expression transgenic mouse lines in which the chicken β-actin promoter and an Edn1 cDNA are separated by a strong stop sequence flanked by loxP sites. In the presence of Cre, the stop cassette is removed, leading to Edn1 expression. Using the Wnt1-Cre strain, in which Cre expression is targeted to the Wnt1-expressing domain of the central nervous system (CNS) from which neural crest cells (NCCs) arise, we show that stable chicken β-actin-Edn1 (CBA-Edn1) transgenic lines with varying EDN1 protein levels develop defects in NCC-derived tissues of the face, though the severity differs between lines. We also show that Edn1 expression can be achieved in other embryonic tissues utilizing other Cre strains, with this expression also resulting in developmental defects. CBA-Edn1 transgenic mice will be useful in investigating diverse aspects of EDN1-mediated-development and disease, including understanding how NCCs achieve and maintain a positional and functional identity and how aberrant EDN1 levels can lead to multiple physiological changes and diseases.

Association of endothelin-1 and matrix metallopeptidase-9 with metabolic syndrome in middle-aged and older adults

BACKGROUND

Metabolic syndrome (MetS) contains a cluster of cardiovascular risk factors. People with MetS are more susceptible to cardiovascular disease, diabetes mellitus, and cancer. Endothelin-1 (ET-1) and matrix metallopeptidase-9 (MMP-9) have been implicated in the development of cardiovascular diseases, diabetes mellitus and cancers. This cross-sectional study aimed to examine the association of ET-1 and MMP-9 with MetS in middle-aged and older Hong Kong Chinese adults.

METHODS

149 adults aged 50 to 92 (n = 75 for non-MetS group and n = 74 for MetS group) were examined. All subjects were screened for MetS according to the diagnostic guideline of the United States National Cholesterol Education Program (NCEP) Expert Panel Adult Treatment Panel (ATP) III criteria. Serum levels of ET-1 and MMP-9 were measured. Independent t test was used to detect differences between non-MetS and MetS groups and between subjects with or without certain metabolic abnormality. The association of the serum concentration of MMP-9 and ET-1 with MetS parameters were examined by Pearson's correlation analysis.

RESULTS

Serum level of ET-1 is higher in MetS-positive subjects and in subjects with high blood pressure, elevated fasting blood glucose, and central obesity. The serum concentration of MMP-9 is higher in subjects positively diagnosed with MetS and subjects with high blood pressure, elevated fasting blood glucose, low blood high-density lipoprotein-cholesterol (HDL-C), high blood triglycerides, and central obesity. Correlation analyses revealed that serum concentration of ET-1 is positively correlated to systolic blood pressure, waist circumference, fasting blood glucose, and age whereas it is negatively correlated to HDL-C. MMP-9 is positively correlated to systolic blood pressure, waist circumference, fasting blood glucose, and age whereas it is negatively correlated to HDL-C.

CONCLUSION

Serum ET-1 is higher in subjects with hypertension, hyperglycemia, central obesity or MetS. Serum MMP-9 is higher in subjects diagnosed with MetS or having either one of the MetS parameters. Both circulating levels of ET-1 and MMP-9 are correlated to systolic blood pressure, waist circumference, fasting blood glucose, HDL-C, and age. Further research is needed to fully dissect the role of ET-1 and MMP-9 in the development of cancers, diabetes and cardiovascular disease in relation to MetS.

Functional changes in pulmonary arterial endothelial cells associated with BMPR2 mutations

Pulmonary arterial hypertension (PAH) is a devastating disease characterized by abnormal remodeling of small, peripheral pulmonary arteries. Germline mutations in the bone morphogenetic protein receptor type 2 (BMPR2) gene are a major risk factor for developing PAH. At present, the correlation between the BMPR2 mutation and the patient's prognosis remains controversial despite several investigations. In this study, we explored the functional effects of four BMPR2 mutations to dissect the functional significance of the BMPR2 gene defect. Cellular immunofluorescence assay of four mutants (Tyr67Cys, Thr268fs, Ser863Asn, and Gln433X) revealed that the BMPR2 protein containing Thr268fs, Ser863Asn, or Gln433X exhibited abnormal subcellular localization. The BrdU incorporation and TUNEL assay suggested that any of the BMPR2 mutations Thr268fs, Ser863Asn, or Gln433X could improve endothelial cell apoptosis and decrease cell proliferation. All of the four mutants could inhibit nitric oxide (NO) synthesis in HLMVE cells, and ET-1 levels increased in the cells transfected with mutant Ser863Asn. Our results will improve the understanding of the genotype-phenotype correlations and mechanisms associated with BMPR2 mutations.

Current state of endothelin receptor antagonism in hypertension and pulmonary hypertension

Endothelin 1 (ET-1), a potent vasoconstrictive substance, was discovered in 1988 by Yanagisawa and colleagues, and since then, a quarter of a century has passed. Understanding the biology of ET-1 has rapidly developed by characterizing the components of its receptors and processing enzymes. Numerous studies have revealed not only physiological but also various pathophysiological roles of the ET system. At first, ET-1 was the attractive and promising target for the treatment of hypertension owing to its potent vasoconstrictive nature and a variety of ET receptor antagonists (ERAs) were studied. However, the clinical application to treat hypertension was disappointing because of the side effects, including liver toxicity and fluid retention. On the other hand, ERAs have been established as orphan drugs for the treatment of pulmonary arterial hypertension and improved the prognosis of patients. Furthermore, multipotency of the ET system in the pathogenesis of multiple diseases has led to the development of translational research not only in the field of hypertension but in a variety of fields. Furthermore, a range of studies are ongoing to apply ERAs to clinical situations. In this article, we review the pathophysiological roles of the ET system in hypertension and pulmonary hypertension and the potential of ET receptor antagonism for the treatment of these diseases.

End o' the line revisited: moving on from nitric oxide to CGRP

When endothelin-1(ET-1) was discovered it was hailed as the prototypical endothelium-derived contracting factor (EDCF). However, over the years little evidence emerged convincingly demonstrating that the peptide actually contributes to moment-to-moment changes in vascular tone elicited by endothelial cells. This has been attributed to the profound inhibitory effect of nitric oxide (NO) on both the production (by the endothelium) and the action (on vascular smooth muscle) of ET-1. Hence, the peptide is likely to initiate acute changes in vascular diameter only under extreme conditions of endothelial dysfunction when the NO bioavailability is considerably reduced if not absent. The present essay discusses whether or not this concept should be revised, in particular in view of the potent inhibitory effect exerted by calcitonin gene related peptide (CGRP) released from sensorimotor nerves on vasoconstrictor responses to ET-1.

Comparative analyses of lung transcriptomes in patients with alveolar capillary dysplasia with misalignment of pulmonary veins and in foxf1 heterozygous knockout mice

Alveolar Capillary Dysplasia with Misalignment of Pulmonary Veins (ACDMPV) is a developmental disorder of the lungs, primarily affecting their vasculature. FOXF1 haploinsufficiency due to heterozygous genomic deletions and point mutations have been reported in most patients with ACDMPV. The majority of mice with heterozygous loss-of-function of Foxf1 exhibit neonatal lethality with evidence of pulmonary hemorrhage in some of them. By comparing transcriptomes of human ACDMPV lungs with control lungs using expression arrays, we found that several genes and pathways involved in lung development, angiogenesis, and in pulmonary hypertension development, were deregulated. Similar transcriptional changes were found in lungs of the postnatal day 0.5 Foxf1^+/− mice when compared to their wildtype littermate controls; 14 genes, COL15A1, COL18A1, COL6A2, ESM1, FSCN1, GRINA, IGFBP3, IL1B, MALL, NOS3, RASL11B, MATN2, PRKCDBP, and SIRPA, were found common to both ACDMPV and Foxf1 heterozygous lungs. Our results advance knowledge toward understanding of the molecular mechanism of ACDMPV, lung development, and its vasculature pathology. These data may also be useful for understanding etiologies of other lung disorders, e.g. pulmonary hypertension, bronchopulmonary dysplasia, or cancer.

Obesity and heterozygous endothelial overexpression of prepro-endothelin-1 modulate responsiveness of mouse main and segmental renal arteries to vasoconstrictor agents

AIMS

Levels of the endothelium-derived peptide endothelin-1 (ET-1) are elevated in obese humans, and ET-1 mediated vascular tone is increased. Renal arterial smooth muscle is highly responsive to ET-1. Whether or not endothelium-derived ET-1 affects contractions of the renal artery under normal conditions or in obesity is unknown. The present study was designed to investigate whether or not overexpression of endogenous ET-1 in the endothelium affects the responsiveness of the main and segmental renal arteries differently in obesity.

MAIN METHODS

Mice with tie-1 promoter-driven endothelium-restricted heterozygous overexpression of preproendothelin-1 were used (TET(het)). Obesity was induced in TET(het) mice and wild-type (WT) littermates by feeding a high fat diet for 30 weeks; lean controls were kept on standard chow. The renal arteries were studied in wire myographs testing contractions (in the presence of l-NAME) to ET-1, serotonin, and U46619.

KEY FINDINGS

Contractions to ET-1 were comparable between groups in main renal arteries, but augmented in segmental preparations from obese mice. Serotonin-induced responses were enhanced in obese TET(het) mice renal arteries compared to lean controls. Concentration-contraction curves to U46619 were shifted significantly to the left in main renal arteries of obese animals, and the maximal response was significantly increased between lean and obese TET(het) mice.

SIGNIFICANCE

These results indicate an augmented responsiveness of main renal arteries in obesity particularly to TP receptor activation. When combined with endothelial ET-1 overexpression this effect is even more pronounced, which may help to gain further insights into the mechanisms of hypertension in obesity.

Preservation of endothelium-dependent relaxation in atherosclerotic mice with endothelium-restricted endothelin-1 overexpression

In human atherosclerosis, which is associated with elevated plasma and coronary endothelin (ET)-1 levels, ETA receptor antagonists improve coronary endothelial function. Mice overexpressing ET-1 specifically in the endothelium (eET-1) crossed with atherosclerosis-prone apolipoprotein E knockout mice (Apoe(-/-)) exhibit exaggerated high-fat diet (HFD)-induced atherosclerosis. Since endothelial dysfunction often precedes atherosclerosis development, we hypothesized that mice overexpressing endothelial ET-1 on a genetic background deficient in apolipoprotein E (eET-1/Apoe(-/-)) would have severe endothelial dysfunction. To test this hypothesis, we investigated endothelium-dependent relaxation (EDR) to acetylcholine in eET-1/Apoe(-/-) mice. EDR in mesenteric resistance arteries from 8- and 16-week-old mice fed a normal diet or HFD was improved in eET-1/Apoe(-/-) compared with Apoe(-/-) mice. Nitric oxide synthase (NOS) inhibition abolished EDR in Apoe(-/-). EDR in eET-1/Apoe(-/-) mice was resistant to NOS inhibition irrespective of age or diet. Inhibition of cyclooxygenase, the cytochrome P450 pathway, and endothelium-dependent hyperpolarization (EDH) resulted in little or no inhibition of EDR in eET-1/Apoe(-/-) compared with wild-type (WT) mice. In eET-1/Apoe(-/-) mice, blocking of EDH or soluble guanylate cyclase (sGC), in addition to NOS inhibition, decreased EDR by 36 and 30%, respectively. The activation of 4-aminopyridine-sensitive voltage-dependent potassium channels (Kv) during EDR was increased in eET-1/Apoe(-/-) compared with WT mice. We conclude that increasing eET-1 in mice that develop atherosclerosis results in decreased mutual dependence of endothelial signaling pathways responsible for EDR, and that NOS-independent activation of sGC and increased activation of Kv are responsible for enhanced EDR in this model of atherosclerosis associated with elevated endothelial and circulating ET-1.

Elevated endothelin-1 (ET-1) levels may contribute to hypoadiponectinemia in childhood obesity

CONTEXT

Pediatric obesity is associated with endothelial dysfunction and hypoadiponectinemia, but the relationship between these two conditions remains to be fully clarified. Whether enhanced release of endothelin-1 (ET-1) may directly impair adiponectin (Ad) production in obese children is not known.

OBJECTIVE

The aim of the study was to explore whether and how high circulating levels of ET-1 may contribute to impair Ad production, release, and vascular activity.

DESIGN AND PARTICIPANTS

Sixty children were included into obese (Ob; n = 30), overweight (OW; n = 11), and lean (n = 19) groups. Total and high-molecular-weight Ad, ET-1, vascular cell adhesion molecule-1, and von Willebrand factor levels were measured in serum samples. Adipocytes were stimulated with exogenous ET-1 or with sera from lean, OW, and Ob, and Ad production and release measured in the absence or in the presence of ETA (BQ-123) and ETB (BQ-788) receptor blockers, p42/44 MAPK inhibitor PD-98059, or c-Jun NH2-terminal protein kinase inhibitor SP-600125. Vasodilation to Ad was evaluated in rat isolated arteries in the absence or in the presence of BQ-123/788.

RESULTS

Total and high-molecular-weight Ad was significantly decreased and ET-1 levels significantly increased in OW (P < .01) and Ob (P < .001) children. A statistically significant linear regression (P < .01) was found between Ad and ET-1. Exposure of adipocytes to exogenous ET-1 or serum from OW and Ob significantly decreased Ad mRNA and protein levels (P < 0.001). The inhibitory effect of ET-1 on Ad was reverted by BQ-123/788 or PD-98059 but not SP-600125. Ad-mediated vasodilation was further increased in arteries pretreated with BQ-123/788.

CONCLUSIONS

ET-1-mediated inhibition of Ad synthesis via p42/44 MAPK signaling may provide a possible explanation for hypoadiponectinemia in pediatric obesity and contribute to the development of cardiovascular complications.

Endothelin and the podocyte

In the past decade, research has advanced our understanding how endothelin contributes to proteinuria and glomerulosclerosis. Data from pre-clinical and clinical studies now provide evidence that proteinuric diseases such as focal segmental glomerulosclerosis and diabetic nephropathy as well as hypertension nephropathy are sensitive to treatment with endothelin receptor antagonists (ERAs). Like blockade of the renin-angiotensin system, ERA treatment-under certain conditions-may even cause disease regression, effects that could be achieved on top of renin-angiotensin-aldosterone system blockade, suggesting independent therapeutic mechanisms by which ERAs convey nephroprotection. Beneficial effects of ERAs on podocyte function, which is essential to maintain the glomerular filtration barrier, have been identified as one of the key mechanisms by which inhibition of the endothelin ETA receptor ameliorates renal structure and function. In this article, we will review pre-clinical studies demonstrating a causal role for endothelin in proteinuric chronic kidney disease (with a particular focus on functional and structural integrity of podocytes in vitro and in vivo). We will also review the evidence suggesting a therapeutic benefit of ERA treatment on the functional integrity of podocytes in humans.