eNOS Activity Research Articles

Abstract 4114308: Defective in LYPLA1-Mediated Lysophosphatidylcholine Metabolism Contributes to Diabetes-Induced Atherosclerosis and Subsequent Myocardial Dysfunction

Background and Objective: Diabetes mellitus (DM) is a chronic metabolic condition that can cause serious damage to blood vessels and the heart. While current metabolomics research mainly focused on metabolic profiles during disease onset or at advanced stages, there remains a gap in understanding the molecular mechanisms of metabolites in the progression of diabetic cardiovascular disease. This study aims to explore effective strategies for preventing cardiovascular complications in diabetics by excavating metabolic pathways and mechanisms. Methods: Peripheral blood samples were obtained from 21 healthy individuals, 20 patients diagnosed with DM, 20 patients with coronary heart disease (CHD), and 25 patients with both DM and CHD (DC). Cardiac function, biochemical parameters and serum metabolome were detected. A specialized methodology with rigorous screening criteria was employed to identify differential metabolites associated with diabetes-induced CHD and cardiomyopathy. Mice were injected with LPC16:0 to assess cardiovascular function. Models of diabetes and diabetic atherosclerosis were induced by STZ injection and high-fat diet feeding in WT and ApoE -/- mice. Cardiac function and differential metabolites in aortic and cardiac tissues were assessed. The effect and molecular mechanism of LYPLA1 on vascular function, mitochondrial function, and metabolites-related enzymes were examined in human aortic endothelial cells (HAECs) and AC16 cardiomyocytes. Results: Cardiac function was markedly declined in DM and DC patients, as well as in mice with diabetes and diabetic atherosclerosis. However, CHD patients and atherosclerosis alone did not exhibit evident cardiac dysfunction. Key metabolites associated with diabetic cardiomyopathy and diabetes-induced CHD were identified as LPE18:1 and LPC16:0, respectively. Intraperitoneal administration of LPC16:0 in mice led to decreased LYPLA1, severe myocardial anomalies, and the appearance of plaques in the aortic arch. Either LYPLA1 knockdown or the treatment with high glucose and palmitic acid in HAECs resulted in impaired mitochondrial function, reduced intracellular NO and eNOS activity, which were mitigated by LYPLA1 overexpression. Conclusion: The metabolite LPC16:0 and the regulatory enzyme LYPLA1 are pivotal in driving the advancement of cardiovascular complications triggered by diabetes. Targeting LYPLA1 could represent a promising strategy for preventing diabetes-induced CHD and subsequent cardiomyopathy.

Abstract 4145829: Fatty Acid Binding Protein 4 as Potential Indicator for Gestational Diabetes Mellitus-Induced Fetal Endothelial Dysfunction

Introduction/Background: Gestational diabetes mellitus (GDM) is the most common complication during pregnancy. GDM is leading to an elevated risk for the development of cardiovascular diseases both in the mother and the child in later life. Previous studies have identified fatty acid-binding protein 4 (FABP4) as a prime candidate involved in the pathophysiology of GDM. Indeed, women with GDM exhibit elevated blood levels of FABP4, suggesting its potential role as a biomarker for endothelial dysfunction and cardiovascular risk assessment in GDM. Research Question/Hypothesis: Does FABP4 affect the function of human endothelial cells from patients with GDM? Goals/Aim: Our aim is a better understanding of the role of FABP4 in fetal endothelial dysfunction of patients with GDM and the development of potential therapeutic strategies. Methods/Approach: Primary human umbilical vein endothelial cells (HUVECs) were isolated from umbilical cords obtained from normoglycemic and GDM pregnancies. Total mRNA from HUVECs was used for bulk RNA sequencing to compare gene expression pattern. HUVECs were subjected to functional analyses assessing proliferation, migration, NO and insulin signaling. Finally, human endothelial cells were exposed to high laminar flow (30 dyn/cm 2 ) or simvastatin (10 nM) treatment to investigate their impact on FABP4 expression and endothelial function. Results/Data: Bulk RNA sequencing data analysis revealed FABP4 as a gene overexpressed in GDM HUVECs compared to normoglycemic controls. Gene set enrichment analysis showed in addition an enrichment of genes involved in angiogenesis and Notch signaling pathways in human endothelial cells from GDM patients. GDM HUVECs had a significantly higher wound healing capacity compared to normoglycemic controls. The PI3K/AKT/mTOR pathway was enriched in GDM HUVECs. GDM HUVECs displayed impaired activation of AKT and eNOS (expression and phosphorylation) after stimulation with insulin, suggesting a possible insulin resistance. Finally, subjecting HUVECs to high laminar shear stress or simvastatin treatment caused a reduction of FABP4 mRNA expression and an increase of eNOS expression, indicating potential therapeutic strategies to improve endothelial function. Conclusions: We provided evidence that FABP4 could be involved in fetal GDM-induced endothelial dysfunction. High laminar shear stress and medications activating eNOS signaling could protect the endothelium against the negative impact of FABP4 in GDM.

Shear stress-stimulated AMPK couples endothelial cell mechanics, metabolism, and vasodilation.

Endothelial cells respond to mechanical force by stimulating cellular signaling, but how these pathways are linked to elevations in cell metabolism and whether metabolism supports the mechanical response remains poorly understood. Here, we show that the application of force to endothelial cells stimulates VE-cadherin to activate liver kinase B1 (LKB1) and AMP-activated protein kinase (AMPK), a master regulator of energy homeostasis. VE-cadherin stimulated AMPK increases eNOS activity and localization to the plasma membrane, reinforcement of the actin cytoskeleton and cadherin adhesion complex, and glucose uptake. We present evidence for the increase in metabolism being necessary to fortify the adhesion complex, actin cytoskeleton, and cellular alignment. Together these data extend the paradigm for how mechanotransduction and metabolism are linked to include a connection to vasodilation, thereby providing new insight into how diseases involving contractile, metabolic, and vasodilatory disturbances arise.

The Adhesion GPCR ADGRL2/LPHN2 Can Protect Against Cellular and Organismal Dysfunction

The most common trigger of sepsis and septic shock is bacterial lipopolysaccharide (LPS). Endothelial cells are among the first to encounter LPS directly. Generally, their function is closely linked to active endothelial NO Synthase (eNOS), which is significantly reduced under septic conditions. LPS treatment of endothelial cells leads to their activation and apoptosis, resulting in loss of integrity and vascular leakage, a hallmark of septic shock. Hence, therapies that prevent endothelial leakage or restore the endothelial barrier would be invaluable for patients. Adhesion GPCRs (aGPCRs) have been largely overlooked in this context, although particularly one of them, ADGRL2/LPHN2, has been implicated in endothelial barrier function. Our study shows that overexpression of ADGRL2 protects endothelial cells from LPS-induced activation, apoptosis, and impaired migration. Mechanistically, ADGRL2 preserves eNOS activity by shifting its binding from Caveolin-1 to Heat Shock Protein 90. Furthermore, ADGRL2 enhances antioxidative responses by increasing NRF2 activity. Notably, we found that this function may be evolutionarily conserved. In the absence of lat-2, a homolog of ADGRL2 in Caenorhabditis elegans, worms show higher ROS levels and altered stress response gene expression. Additionally, lat-2 mutants have a significantly reduced lifespan, altogether indicating a protective role of ADGRL2 against oxidative stress across species.

The effect of CD38 inhibition in age-associated vascular dysfunction

Abstract Introduction Aging is characterized by age-related vascular dysfunction, mainly caused by endothelial dysfunction and arterial stiffness. Levels of nicotinamide adenine dinucleotide (NAD) decrease with aging and accordingly, NAD is thought to be involved in the progression of age-related vascular dysfunction. Recent studies reported the involvement of CD38 in NAD regulation; indeed, its inhibition significantly prolongs the lifespan of progeroid and aged mice. However, whether CD38 is involved in the progression of age-related vascular dysfunction remains to be investigated. Methods CD38 expression was investigated in aortic homogenates of young (12-16 weeks) and aged (18-24 months) C57BL/6 wild-type mice, as well as in vitro in young (passage 5-7) and senescent (passage 14-15) primary human aortic endothelial cells (HAECs). Ex vivo tension myograph experiments were performed on thoracic aortas isolated from aged C57BL/6 mice (22-24 months old) pre-incubated for 1 hour with CD38-specific inhibitor, 78c, or DMSO as control. The effect of CD38 inhibition was also observed in vitro in senescent HAECs. Results A significant upregulation of CD38 expression was detected in the aortas of aged mice compared to the young ones as well as in senescent HAECs compared to young cells. Ex vivo tension myograph experiments showed a significant increase in endothelium-dependent relaxation responses to acetylcholine upon CD38 inhibition. The improvement of endothelial function was prevented by the addition of endothelial nitric oxide synthase (eNOS) inhibitor (L-NAME), but not by the COXs inhibitor, indomethacin, indicating that the observed effect achieved by CD38 inhibition is eNOS dependent. The involvement of the eNOS pathway was further supported by the in vitro finding in HAECs of increased eNOS activation upon CD38 inhibition. Conclusion The herein-reported data suggests an involvement of CD38 in the development of age-related endothelial dysfunction. Further studies are ongoing to investigate the underlying molecular mechanisms as well as the effect of long-term CD38 inhibitor supplementation on the progression of age-related vascular dysfunction.

Comprehensive analysis of VEGF/VEGFR inhibitor-induced immune-mediated hypertension: integrating pharmacovigilance, clinical data, and preclinical models.

This study aimed to elucidate the differential immunological mechanisms and characteristics of hypertension induced by VEGF inhibitors (VEGFi) and VEGF receptor inhibitors (VEGFRi), with the goal of optimizing monitoring strategies and treatment protocols. We investigated the risk of immune-related adverse events associated with VEGFi/VEGFRi-induced hypertension by analyzing the FDA Adverse Event Reporting System (FAERS) database. Findings were corroborated with blood pressure characteristics observed in clinical patients and preclinical models exposed to various VEGF/VEGFRi. Clinical and preclinical studies were conducted to compare immunological responses and hypertension profiles between inhibitor classes. An integrative analysis across cancer types and species was performed, focusing on key signaling pathways. Analysis of FAERS data, in conjunction with clinical observations, revealed that both VEGFi and VEGFRi significantly elevated the risk of immune-mediated, blood pressure-related adverse events (ROR=7.75, 95% CI: 7.76-7.95). Subsequent clinical and preclinical studies demonstrated differential immunological responses and hypertension profiles between inhibitor classes. VEGFRi exhibited a more rapid onset, greater blood pressure elevation, and higher incidence of immune-mediated adverse events compared to VEGFi (Systolic BP: ROR=0 for VEGFi vs. ROR=12.25, 95% CI: 6.54-22.96 for VEGFRi; Diastolic BP: ROR=5.09, 95% CI: 0.60-43.61 for VEGFi vs. ROR=12.90, 95% CI: 3.73-44.55 for VEGFRi). Integrative analysis across cancer types and species, focusing on key signaling pathways, revealed that VEGF/VEGFRi-induced blood pressure elevation was associated with immunomodulation of the mitogen activated protein kinase (MAPK) pathway (R=-0.379, P=0.0435), alterations in triglyceride metabolism (R=-0.664, P=0.0001), modulation of myo-inositol 1,4,5-trisphosphate-sensitive calcium release channel activity (R=0.389, P=0.0378), and dysregulation of nitric oxide eNOS activation and metabolism (R=-0.439, P=0.0179). The temporal dynamics of these effects demonstrated greater significance than dose-dependent responses. Both VEGFi and VEGFRi significantly augmented the risk of immune-mediated, blood pressure-related adverse events, with VEGFRi inducing a more rapid and pronounced onset of blood pressure elevation and a higher incidence of immune-related, blood pressure-associated adverse events compared to VEGFi.

Lack of AMP-activated protein kinase-α1 reduces nitric oxide synthesis in thoracic aorta perivascular adipose tissue

ObjectivePerivascular adipose tissue (PVAT) releases anti-contractile bioactive molecules including NO. PVAT anti-contractile activity is attenuated in mice lacking AMPKα1 (AMP-activated protein kinase-α1). As AMPK regulates endothelial NO synthase (eNOS) activity in cultured cells, NO synthesis was examined in PVAT from AMPKα1 knockout (KO) mice. Methods and resultsEndothelium-denuded thoracic or abdominal aortic rings were isolated from wild type (WT) and KO mice. NOS inhibition enhanced vasoconstriction in PVAT-intact thoracic aortic rings from mice of either genotype yet had no effect on abdominal rings as assessed by wire myography. Thoracic aorta PVAT exhibited increased NO production, NOS activity and levels of the brown adipose tissue marker uncoupling protein-1 (UCP1) compared to abdominal PVAT. In KO mice, NO production was significantly reduced in thoracic but not abdominal PVAT. Reduced NO production in KO thoracic PVAT was not due to altered levels or phosphorylation of eNOS but was associated with increased caveolin-1:eNOS association and caveolin-1 Tyr14 phosphorylation. A peptide that disrupts eNOS:caveolin-1 association increased NO synthesis and reduced vasoconstriction of PVAT-intact thoracic but not abdominal aortic rings. KO thoracic PVAT also exhibited reduced UCP1 levels. ConclusionsMurine thoracic aorta PVAT exhibits higher NO synthesis and UCP1 levels than abdominal aortic PVAT. Downregulation of AMPK suppresses NO synthesis which may contribute to the reduced anticontractile activity and reduced brown adipose tissue phenotype of KO thoracic PVAT. The mechanism underlying the effect of AMPK downregulation likely results from increased caveolin-1:eNOS association associated with caveolin-1 Tyr14 phosphorylation.

Angiopoietin-2 reverses endothelial cell dysfunction in progeria vasculature.

Hutchinson-Gilford progeria syndrome (HGPS) is a rare premature aging disorder in children caused by a point mutation in the lamin A gene, resulting in a toxic form of lamin A called progerin. Accelerated atherosclerosis leading to heart attack and stroke are the major causes of death in these patients. Endothelial cell (EC) dysfunction contributes to the pathogenesis of HGPS related cardiovascular diseases (CVD). Endothelial cell-cell communications are important in the development of the vasculature, and their disruptions contribute to cardiovascular pathology. However, it is unclear how progerin interferes with such communications that lead to vascular dysfunction. An antibody array screening of healthy and HGPS patient EC secretomes identified Angiopoietin-2 (Ang2) as a down-regulated signaling molecule in HGPS ECs. A similar down-regulation of Ang2 mRNA and protein was detected in the aortas from an HGPS mouse model. Addition of Ang2 to HGPS ECs rescues vasculogenesis, normalizes endothelial cell migration and gene expression, and restores nitric oxide bioavailability through eNOS activation. Furthermore, Ang2 addition reverses unfavorable paracrine effects of HGPS ECs on vascular smooth muscle cells. Lastly, by utilizing adenine base editor (ABE)-corrected HGPS ECs and progerin-expressing HUVECs, we demonstrated a negative correlation between progerin and Ang2 expression. Lastly, our results indicated that Ang2 exerts its beneficial effect in ECs through Tie2 receptor binding, activating an Akt-mediated pathway. Together, these results provide molecular insights into EC dysfunction in HGPS and suggest that Ang2 treatment has potential therapeutic effects in HGPS-related CVD.

DDAH1 deficiency exacerbates cerebral vascular endothelial dysfunction by aggravating BBB disruption and oxidative stress in thoracic blast-induced brain injury

As terrorist incidents and underground explosion events have become more frequent around the world, brain injury caused by thoracic blast exposure has been more highlighted due to its injured organ, subsequent social and economic burden. It has been reported dimethylarginine dimethylaminohydrolase 1 (DDAH1) plays important roles in regulating vascular endothelial injury repair and angiogenesis, but its role in thoracic blast-induced brain injury remains to be explained. This study seeks to investigate the mechanism of DDAH1 on thoracic blast-induced brain injury. 40 C57BL/6 wild type mice and 40 DDAH1 knockout mice were randomly and equally divided into control group and blast group, respectively. The integrity of blood-brain barrier (BBB) was detected by Evans blue test. The serum inflammatory factors, nitric oxide (NO) contents, and asymmetric dimethylarginine (ADMA) levels were determined through ELISA. HE staining and reactive oxygen species (ROS) detection were performed for histopathological changes. Western blot was used to detect the proteins related to oxidative stress, tight junction, focal adhesion, vascular endothelial injury, and the DDAH1/ADMA/eNOS signaling pathway. DDAH1 deficiency aggravated thoracic blast-induced BBB leakage, inflammatory response, and the increased levels of inflammatory-related factors. Additionally, DDAH1 deficiency also increased ROS generation, MDA and IRE-α expression. Regarding cerebral vascular endothelial dysfunction, DDAH1 deficiency increased the expression of MCAM, FN1, LIMK1, VEGF, MMP9, Vimentin and N-cadherin, while lowering the expression of FMR1, Occludin, claudin-3, claudin-5, Lyn, LIMA1, Glrb, Sez6, Dystrophin, and phosphorylation of VASP. Also, DDAH1 deficiency exacerbated explosion-induced increase of ADMA and decrease of eNOS activity and NO contents. Thus, we conclude that DDAH1 could prevent cerebral vascular endothelial dysfunction and related injury by inhibiting ADMA signaling and increasing eNOS activity in thoracic blast induced brain injury.

Evaluation of anti-hypertensive activity of Quercus leucotrichophora A. camus methanolic extract on DOCA-salt induced hypertensive rats

Quercus leucotrichophora A. camus, commonly known as Banj oak or Ban tree, belongs to the Fagaceae family and is abundantly found in the regions of Shimla, Kullu-Manali, and upper Mandi in Himachal Pradesh. This study explores the medicinal properties of plant seeds, known for their antioxidant and diuretic activity, traditionally utilized in the treatment of hypertension and hypolipidemic, hepatoprotective conditions. PurposeTo investigate the antihypertensive effect of methanolic extract of Quercus leucotrichophora A. camus seeds in DOCA sat induced rats. Material and methodsGround seeds of Quercus leucotrichophora A. camus were stored in an airtight container. A total of 100 gs of dried seed powder were subjected to extraction using 250 ml of methanol and a Soxhlet extractor maintained at 60–65 °C for five hours. The resulting dried extract (5 gs) was stored in an airtight container in a refrigerator at low temperature and administered by rats to test its antihypertensive impact. The assessment of obtained extract impact on hypertension induced by DOCA-salt was conducted through blood pressure measurement and biochemical analysis. ResultsOur study revealed that the methanolic extract of Quercus leucotrichophora A. camus seeds exerted blood pressure-lowering effects, associated with an increase in serum Nitric Oxide (NO) levels. The attenuation of hypertension by extract was further linked to the normalization of serum Na+ and K+concentrations, indicating an improvement in electrolyte imbalance. Additionally, the antioxidant properties of Quercus leucotrichophora A. camus were evident through increased activities of Glutathione (GSH), Glutathione Peroxidase (GHPx), Superoxide Dismutase (SOD), and decrease activity of Thiobarbituric acid reactive substances (TBARS). ConclusionThe findings of our investigation suggest that the antihypertensive action of Quercus leucotrichophora A. camus is correlated with enhanced endothelial nitric oxide synthase (eNOS) activation and an augmented antioxidant defense system. This sheds light on the potential therapeutic benefits of plant under investigation in managing hypertension, emphasizing its role in promoting cardiovascular health. Further research is warranted to elucidate the underlying mechanisms and to explore the full pharmacological potential of Quercus leucotrichophora A. camus in the field of cardiovascular medicine.

Signaling Paradigms of H2S-Induced Vasodilation: A Comprehensive Review.

Hydrogen sulfide (H2S), a gas traditionally considered toxic, is now recognized as a vital endogenous signaling molecule with a complex physiology. This comprehensive study encompasses a systematic literature review that explores the intricate mechanisms underlying H2S-induced vasodilation. The vasodilatory effects of H2S are primarily mediated by activating ATP-sensitive potassium (K_ATP) channels, leading to membrane hyperpolarization and subsequent relaxation of vascular smooth muscle cells (VSMCs). Additionally, H2S inhibits L-type calcium channels, reducing calcium influx and diminishing VSMC contraction. Beyond ion channel modulation, H2S profoundly impacts cyclic nucleotide signaling pathways. It stimulates soluble guanylyl cyclase (sGC), increasing the production of cyclic guanosine monophosphate (cGMP). Elevated cGMP levels activate protein kinase G (PKG), which phosphorylates downstream targets like vasodilator-stimulated phosphoprotein (VASP) and promotes smooth muscle relaxation. The synergy between H2S and nitric oxide (NO) signaling further amplifies vasodilation. H2S enhances NO bioavailability by inhibiting its degradation and stimulating endothelial nitric oxide synthase (eNOS) activity, increasing cGMP levels and potent vasodilatory responses. Protein sulfhydration, a post-translational modification, plays a crucial role in cell signaling. H2S S-sulfurates oxidized cysteine residues, while polysulfides (H2Sn) are responsible for S-sulfurating reduced cysteine residues. Sulfhydration of key proteins like K_ATP channels and sGC enhances their activity, contributing to the overall vasodilatory effect. Furthermore, H2S interaction with endothelium-derived hyperpolarizing factor (EDHF) pathways adds another layer to its vasodilatory mechanism. By enhancing EDHF activity, H2S facilitates the hyperpolarization and relaxation of VSMCs through gap junctions between endothelial cells and VSMCs. Recent findings suggest that H2S can also modulate transient receptor potential (TRP) channels, particularly TRPV4 channels, in endothelial cells. Activating these channels by H2S promotes calcium entry, stimulating the production of vasodilatory agents like NO and prostacyclin, thereby regulating vascular tone. The comprehensive understanding of H2S-induced vasodilation mechanisms highlights its therapeutic potential. The multifaceted approach of H2S in modulating vascular tone presents a promising strategy for developing novel treatments for hypertension, ischemic conditions, and other vascular disorders. The interaction of H2S with ion channels, cyclic nucleotide signaling, NO pathways, ROS (Reactive Oxygen Species) scavenging, protein sulfhydration, and EDHF underscores its complexity and therapeutic relevance. In conclusion, the intricate signaling paradigms of H2S-induced vasodilation offer valuable insights into its physiological role and therapeutic potential, promising innovative approaches for managing various vascular diseases through the modulation of vascular tone.

Circulating extracellular microvesicles associated with electronic cigarette use increase endothelial cell inflammation and reduce nitric oxide production.

The purpose of this study was to determine the effect of circulating microvesicles isolated from chronic electronic (e-)cigarette users on cultured human umbilical vein endothelial cell (HUVEC) expression of nuclear factor-κB (NF-κB), cellular cytokine release, phosphorylation of endothelial nitric oxide synthase (eNOS) and NO production. The HUVECs were treated with microvesicles isolated via flow cytometry from nine non-tobacco users (five male and four female; 22±2years of age) and 10 e-cigarette users (six male and four female; 22±2years of age). Microvesicles from e-cigarette users induced significantly greater release of interleukin-6 (183.4±23.6vs. 150.6±15.4 pg/mL; P=0.002) and interleukin-8 (160.0±31.6vs. 129.4±11.2 pg/mL; P=0.01), in addition to expression of p-NF-κB p65 (Ser536) (18.8±3.4 vs. 15.6±1.5 a.u.; P=0.02) from HUVECs compared with microvesicles from non-tobacco users. Nuclear factor-κB p65 was not significantly different between microvesicles from the non-tobacco users and from the e-cigarette users (87.6±8.7vs. 90.4±24.6 a.u.; P=0.701). Neither total eNOS (71.4±21.8vs. 80.4±24.5 a.u.; P=0.413) nor p-eNOS (Thr495) (229.2±26.5vs. 222.1±22.7 a.u.; P=0.542) was significantly different between microvesicle-treated HUVECs from non-tobacco users and e-cigarette users. However, p-eNOS (Ser1177) (28.9±6.2vs. 45.8±9.0 a.u.; P<0.001) expression was significantly lower from e-cigarette users compared with non-tobacco users. Nitric oxide production was significantly lower (8.2±0.6vs. 9.7±0.9μmol/L; P=0.001) in HUVECs treated with microvesicles from e-cigarette users compared with microvesicles from non-tobacco users. This study demonstrated increased NF-κB activation and inflammatory cytokine production, in addition to diminished eNOS activity and NO production resulting from e-cigarette use. HIGHLIGHTS: What is the central question of this study? Circulating microvesicles contribute to cardiovascular health and disease via their effects on the vascular endothelium. The impact of electronic (e-)cigarette use on circulating microvesicle phenotype is not well understood. What is the main finding and its importance? Circulating microvesicles from e-cigarette users increase endothelial cell inflammation and impair endothelial nitric oxide production. Endothelial inflammation and diminished nitric oxide bioavailability are central factors underlying endothelial dysfunction and, in turn, cardiovascular disease risk. Deleterious changes in the functional phenotype of circulating microvesicles might contribute to the reported adverse effects of e-cigarette use on cardiovascular health.

Vascular endothelial cell morphology and alignment regulate VEGF-induced endothelial nitric oxide synthase activation.

Nitric oxide (NO) production by endothelial nitric oxide synthase (eNOS) inhibits platelet and leukocyte adhesion while promoting vasorelaxation in smooth muscle cells. Dysfunctional regulation of eNOS is a hallmark of various vascular pathologies, notably atherosclerosis, often associated with areas of low shear stress on endothelial cells (ECs). While the link between EC morphology and local hemodynamics is acknowledged, the specific impact of EC morphology on eNOS regulation remains unclear. Morphological differences between elongated, aligned ECs and polygonal, randomly oriented ECs correspond to variations in focal adhesion and cytoskeletal organization, suggesting differing levels of cytoskeletal prestress. However, the functional outcomes of cytoskeletal prestress, particularly in the absence of shear stress, are not extensively studied in ECs. Some evidence suggests that elongated ECs exhibit decreased immunogenicity and enhanced NO production. This study aims to elucidate the signaling pathways governing VEGF-stimulated eNOS regulation in the aligned EC phenotype characterized by elongated and aligned cells within a monolayer. Using anisotropic topographic cues, bovine aortic endothelial cells (BAECs) were elongated and aligned, followed by VEGF treatment in the presence or absence of cytoskeletal tension inhibitors. Phosphorylation of eNOS ser1179, AKT ser437 and FAK Tyr397 in response to VEGF challenge were significantly heightened in aligned ECs compared to unaligned ECs. Moreover this response proved to be robustly tied to cytoskeletal tension as evinced by the abrogation of responses in the presence of the myosin II ATPase inhibitor, blebbistatin. Notably, this work demonstrates for the first time the reliance on FAK phosphorylation in VEGF-mediated eNOS activation and the comparatively greater contribution of the cytoskeletal machinery in propagating VEGF-eNOS signaling in aligned and elongated ECs. This research underscores the importance of utilizing appropriate vascular models in drug development and sheds light on potential mechanisms underlying vascular function and pathology that can help inform vascular graft design.

Polyphenol-rich Aronia melanocarpa juice sustains eNOS activation through phosphorylation and expression via redox-sensitive pathways in endothelial cells.

A sustained formation of nitric oxide (NO) by endothelial nitric oxide synthase (eNOS) is crucial to safeguard the vascular system against the development of cardiovascular diseases. This study investigated the prolonged phosphorylation and expression of eNOS induced by polyphenol-rich Aronia melanocarpa juice (AMJ), along with its underlying mechanisms. The findings revealed that AMJ triggered concentration- and time-dependent increases in eNOS phosphorylation and expression, leading to sustained NO production for 15h. Investigations with various enzymes and inhibitors revealed that the effect of AMJ was associated with redox sensitivity, activating the PI3-kinase/Akt, JNK, and p38 MAPK pathways. These pathways led to the inactivation of transcription factors FoxO1 and FoxO3a through phosphorylation, relieving their repression on eNOS expression. Therefore, the capability of AMJ to consistently trigger prolonged eNOS phosphorylation and expression via complex redox-sensitive pathways highlights its potential for maintaining vascular health and preventing cardiovascular diseases.

Abstract P161: A Single-Short Partial Reprogramming of the Endothelial Cells Decreases Blood Pressure Via Attenuation of Endothelial-to-Mesenchymal Transition in Hypertensive Mice

Small artery remodeling and endothelial dysfunction are hallmarks of hypertension. Growing evidence supports a likely causal association between cardiovascular diseases and the presence of endothelial-to-mesenchymal transition (EndMT). EC reprogramming represents an innovative strategy in regenerative medicine to prevent deleterious effects induced by cardiovascular diseases. Using reprogramming of ECs, via overexpression of Oct-3/4, Sox-2, and Klf-4 (OSK) transcription factors, we aimed to bring ECs back to a youthful phenotype in hypertensive mice. Mouse ECs were infected with lentiviral vectors (LV) containing the specific EC marker cadherin 5 (Cdh5) and the fluorescent reporter enhanced green fluorescence protein (EGFP) with empty vector (LVCO) or with OSK (LV-OSK). Confocal microscopy and western blotting analysis were used to confirm the OSK overexpression. Human aortic ECs (HAoECs) from male and female normotensive and hypertensive patients were analyzed after OSK or control treatments for their endothelial nitric oxide synthase (eNOS) levels, nitric oxide (NO), and genetic profile. Male and female normotensive (BPN/3J) and hypertensive (BPH/2J) mice were treated with an intravenous (i.v.) injection of LVCO or LV-OSK and evaluated 10 days post-infection. The blood pressure, vascular reactivity of small arteries, in vivo EGFP signal and EndMT inhibition were analyzed. Data were analyzed using One-way or Two-way ANOVA, with Tukey post-hoc ( p &lt;0.05). OSK overexpression induced partial EC reprogramming in vitro . OSK treatment of male but not female hypertensive BPH/2J mice normalized blood pressure (BPH/2J LVCO: 105±2mmHg, n=6 versus BPH/2J LV-OSK: 90±2mmHg, n=5) and resistance arteries hypercontractility (BPH/2J LV-CO: 10.50±0.82mN versus BPH/2J LV-OSK: 7.12±0.6mN, n=5), via the attenuation of EndMT (BPH/2J LVCO: 0.041±0.01AU, n=3 versus BPH/2J LV-OSK: 0.007±0.004 AU, n=3) and elastin breaks. EGFP signal was detected in vivo in the prefrontal cortex of BPN/3J and BPH/2J-treated mice, but OSK induced angiogenesis in male BPN/3J mice. OSK-treated human ECs from hypertensive patients showed high eNOS activation and NO production, with low ROS. Single-cell RNA analysis showed that OSK alleviated EC senescence and EndMT, restoring their phenotypes in human ECs from hypertensive patients. Overall, these data indicate that OSK treatment and EC reprogramming can decrease blood pressure and reverse hypertension-induced vascular damage.

Preparation and Vasodilation Mechanism of Angiotensin-I-Converting Enzyme Inhibitory Peptide from Ulva prolifera Protein.

Ulva prolifera, a type of green algae that can be consumed, was utilized in the production of an angiotensin-I converting enzyme (ACE) inhibitory peptide. The protein from the algae was isolated and subsequently hydrolyzed using a neutral protease. The resulting hydrolysate underwent several processes including Sephadex-G100 filtration chromatography, ultrafiltration, HPLC-Q-TOF-MS analysis, ADMET screening, UV spectrum detection test, molecular docking, and molecular dynamic simulation. Then, the ACE inhibitory peptide named KAF (IC50, 0.63 ± 0.26 µM) was identified. The effectiveness of this peptide in inhibiting ACE can be primarily attributed to two conventional hydrogen bonds. Additionally, it could activate endothelial nitric oxide synthase (eNOS) activity to promote the generation of nitric oxide (NO). Additionally, KAF primarily increased the intracellular calcium (Ca2+) level by acting on L-type Ca2+ channel (LTCC) and the ryanodine receptor (RyR) in the endoplasmic reticulum, and completed the activation of eNOS under the mediation of protein kinase B (Akt) signaling pathway. Our study has confirmed that KAF has the potential to be processed into pharmaceutical candidate functions on vasoconstriction.

The vasodilator effect of Eugenol on uterine artery – potential therapeutic applications in pregnancy-associated hypertension

Preeclampsia, a gestational associated hypertension, has been reported in 6–8% of pregnant women worldwide leading to premature delivery and low birth weight of newborn due to reduced blood flow to placenta. Although several vasodilators (Methyl dopa, hydralazine, β-blockers and diuretics) are currently in use to treat preeclampsia, still there is a search for safer drugs with better efficacy. Lately, antihypertensive vasodilators from natural sources are gaining importance in treating preeclampsia. Eugenol (Eug), a natural essential oil, has been traditionally used in health and food products without any risk. In the present study, ex vivo experiments were designed to examine the vasorelaxation effect of Eug and its signaling pathways in a middle uterine artery (MUA) of pregnant Capra hircus (Ch). In presence of different blockers (L-NAME, indomethacin, ODQ, Ouabain, glibenclamide, 4-AP, Ba2, Carbenoxolone and 18β Glycyrrhetinic acid), Eug-induced concentration-dependent vasorelaxation response was elicited. The results showed that Eug caused a greater vasorelaxation effect in the MU of pregnant animals, which is mediated by potential activation of eNOS, KATP channels, and Kir channels with moderate activation of Na+- K+- ATPase and sGC and MEGJ. These findings provide a strong basis for developing Eug as a therapeutic candidate in the treatment of pregnancy-associated hypertension.

Tracer-based metabolomics for profiling nitric oxide metabolites in a 3D microvessels-on-chip model.

Endothelial dysfunction, prevalent in cardiovascular diseases (CVDs) and linked to conditions like diabetes, hypertension, obesity, renal failure, or hypercholesterolemia, is characterized by diminished nitric oxide (NO) bioavailability-a key signaling molecule for vascular homeostasis. Current two-dimensional (2D) invitro studies on NO synthesis by endothelial cells (ECs) lack the crucial laminar shear stress, a vital factor in modulating the NO-generating enzyme, endothelial nitric oxide synthase (eNOS), under physiological conditions. Here we developed a tracer-based metabolomics approach to measure NO-specific metabolites with mass spectrometry (MS) and show the impact of fluid flow on metabolic parameters associated with NO synthesis using 2D and 3D platforms. Specifically, we tracked the conversion of stable-isotope labeled NO substrate L-Arginine to L-Citrulline and L-Ornithine to determine eNOS activity. We demonstrated clear responses in human coronary artery endothelial cells (HCAECs) cultured with 13C6, 15N4-L-Arginine, and treated with eNOS stimulator, eNOS inhibitor, and arginase inhibitor. Analysis of downstream metabolites, 13C6, 15N3 L-Citrulline and 13C5, 15N2 L-Ornithine, revealed distinct outcomes. Additionally, we evaluated the NO metabolic status in static 2D culture and 3D microvessel models with bidirectional and unidirectional fluid flow. Our 3D model exhibited significant effects, particularly in microvessels exposed to the eNOS stimulator, as indicated by the 13C6, 15N3 L-Citrulline/13C5, 15N2 L-Ornithine ratio, compared to the 2D culture. The obtained results indicate that the 2D static culture mimics an endothelial dysfunction status, while the 3D model with a unidirectional fluid flow provides a more representative physiological environment that provides a better model to study endothelial dysfunction.

ShSPI Inhibits Thrombosis Formation and Ischemic Stroke In Vivo.

Thrombotic diseases, emerging as a global public health hazard with high mortality and disability rates, pose a significant threat to human health and longevity. Although current antithrombotic therapies are effective in treating these conditions, they often carry a substantial risk of bleeding, highlighting the urgent need for safer therapeutic alternatives. Recent evidence has increasingly pointed to a connection between elastase activity and thrombosis. In the current study, we investigated the antithrombotic effects of ShSPI, an elastase inhibitor peptide derived from the venom of Scolopendra hainanum. Results showed that ShSPI significantly attenuated carrageenan-induced thrombosis in vivo. Furthermore, ShSPI effectively inhibited the carrageenan-induced decrease in serum superoxide dismutase (SOD) activity and increase in prothrombin time, fibrinogen level, and endothelial nitric oxide synthase (eNOS) activity. In addition, ShSPI reduced intracerebral thrombosis and improved functional outcomes following ischemic stroke in a transient middle cerebral artery occlusion (tMCAO) mouse model. Collectively, these findings suggest that ShSPI is a promising candidate for the development of novel thrombotic therapies.

Human β-casein-derived peptide BCCY-1 improved the intestinal barrier integrity by regulating the TLR4/eNOS/3-Nitrotyrosine axis

Necrotizing enterocolitis (NEC) is a lethal gastrointestinal disease affecting premature infants. Although earlier studies have highlighted protective effects of milk-derived peptides against NEC, the role of the human β-casein-derived peptide BCCY-1 in intestinal barrier protection has never been investigated. Here, we showed that BCCY-1 alleviated the phenotype of NEC, reduced intestinal expression of Toll-like receptor 4 (TLR4) and interleukin-6, and improved the intestinal barrier integrity. NEC-associated multi-organ injury and impaired bone marrow hematopoiesis were also attenuated by BCCY-1. Metabolic screening revealed significant changes in intestinal metabolites in the NEC and NEC + BCCY-1 groups. Further analysis disclosed inhibition of 3-Nitrotyrosine formation due to the preservation of endothelial nitric oxide synthase (eNOS) activity, which was associated with the interactions between BCCY-1 and lipopolysaccharides, leading to disruption of TLR4 signaling. Our findings suggested that BCCY-1 improved intestinal barrier integrity through modulating the TLR4/eNOS/3-Nitrotyrosine axis, highlighting its potential role in the maintenance of intestinal health.