Abstract 3: Cellular Contributions of the Circadian Clock in Atherogenesis

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Xueling Li ◽  
Ling Ruan ◽  
Austin Bentley ◽  
Stephen Haigh ◽  
Yuqing Huo ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Endothelial Cells ◽  
Circadian Rhythm ◽  
Circadian Clock ◽  
Cell Types ◽  
No Production ◽  
Light Cycle ◽  
Lipid Uptake ◽  
Enhanced Production ◽  
The Impact

Atherosclerosis is a leading cause of death despite the improvements in lipid and blood pressure control. The circadian clock, a molecular network of genes and proteins that controls 24-hour timing, has emerged to have a surprising role in the control of metabolic and vascular function. Herein we examined the impact of circadian rhythm dysfunction in atherogenesis by implementation of vascular transplant and PCSK9 based approaches to induce accelerated lesion development in mice. We find that atherogenesis is exacerbated in Bmal1-KO aortic grafts immersed in the hypercholesterolemic milieu of ApoE -/- mice. To assess if atherosclerosis was ‘circadian rhythm dependent’ we subjected wild-type mice to a shortened light cycle (4L/4D) and induced atherosclerosis by intravenous injection of a human PCSK-9 adeno associated virus. Atherosclerosis in the jet-lagged PCSK-9 mice was robustly increased relative to the atherosclerosis observed in WT mice on a normal light cycle (12L/12D), providing further evidence that circadian rhythm and the circadian clock contribute to atherosclerosis. However, atherosclerosis is a complex disease that is the net result of interplay between intrinsic (vascular cells) and extrinsic mechanisms (metabolism, blood pressure, and hormones) and the importance of clock function in individual cell types is poorly understood. We found that deletion or silencing of key circadian transcription factors resulted in an enhanced inflammatory and pro-oxidant phenotype with diminished NO production and greater lipid uptake in both macrophages and endothelial cells. Loss of circadian function in smooth muscle cells similarly resulted in enhanced production of reactive oxygen species and greater cell proliferation. Surprising, the silencing of Bmal2 in endothelial cells resulted in greater lipid uptake in oxLDL treated HAEC as well as increased expression of markers of autophagy, suggesting that Bmal2 may orchestrate numerous output functions in different cell types. In conclusion, we find that the circadian clock and circadian rhythm have a profound impact on atherosclerosis, to influence vascular cell inflammatory and lipid uptake responses, and identify an unexpectedly prominent role for the side-partner of Bmal1, Bmal2.

scholarly journals Characterization of CD38 in the major cell types of the heart: endothelial cells highly express CD38 with activation by hypoxia-reoxygenation triggering NAD(P)H depletion

2018 ◽  
Vol 314 (3) ◽  
pp. C297-C309 ◽  
Author(s):  
James Boslett ◽  
Craig Hemann ◽  
Fedias L. Christofi ◽  
Jay L. Zweier
Keyword(s):  
Endothelial Cells ◽  
Endothelial Dysfunction ◽  
Cardiac Myocytes ◽  
Cell Types ◽  
No Production ◽  
Imaging Method ◽  
Enos Uncoupling ◽  
The Impact ◽  
Hypoxia Reoxygenation

The NAD(P)+-hydrolyzing enzyme CD38 is activated in the heart during the process of ischemia and reperfusion, triggering NAD(P)(H) depletion. However, the presence and role of CD38 in the major cell types of the heart are unknown. Therefore, we characterize the presence and function of CD38 in cardiac myocytes, endothelial cells, and fibroblasts. To comprehensively evaluate CD38 in these cells, we measured gene transcription via mRNA, as well as protein expression and enzymatic activity. Endothelial cells strongly expressed CD38, while only low expression was present in cardiac myocytes with intermediate levels in fibroblasts. In view of this high level expression in endothelial cells and the proposed role of CD38 in the pathogenesis of endothelial dysfunction, endothelial cells were subjected to hypoxia-reoxygenation to characterize the effect of this stress on CD38 expression and activity. An activity-based CD38 imaging method and CD38 activity assays were used to characterize CD38 activity in normoxic and hypoxic-reoxygenated endothelial cells, with marked CD38 activation seen following hypoxia-reoxygenation. To test the impact of hypoxia-reoxygenation-induced CD38 activation on endothelial cells, NAD(P)(H) levels and endothelial nitric oxide synthase (eNOS)-derived NO production were measured. Marked NADP(H) depletion with loss of NO and increase in superoxide production occurred following hypoxia-reoxygenation that was prevented by CD38 inhibition or knockdown. Thus, endothelial cells have high expression of CD38 which is activated by hypoxia-reoxygenation triggering CD38-mediated NADP(H) depletion with loss of eNOS-mediated NO generation and increased eNOS uncoupling. This demonstrates the importance of CD38 in the endothelium and explains the basis by which CD38 triggers post-ischemic endothelial dysfunction.

scholarly journals VE-PTP inhibition elicits eNOS phosphorylation to blunt endothelial dysfunction and hypertension in diabetes

2020 ◽  
Author(s):  
Mauro Siragusa ◽  
Alberto Fernando Oliveira Justo ◽  
Pedro Felipe Malacarne ◽  
Anna Strano ◽  
Akshay Buch ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Endothelial Dysfunction ◽  
Vascular Reactivity ◽  
Therapeutic Option ◽  
Diabetic Patients ◽  
No Production ◽  
Vascular Endothelial ◽  
Enos Activity

Abstract Aims Receptor-type vascular endothelial protein tyrosine phosphatase (VE-PTP) dephosphorylates Tie-2 as well as CD31, VE-cadherin, and vascular endothelial growth factor receptor 2 (VEGFR2). The latter form a signal transduction complex that mediates the endothelial cell response to shear stress, including the activation of the endothelial nitric oxide (NO) synthase (eNOS). As VE-PTP expression is increased in diabetes, we investigated the consequences of VE-PTP inhibition (using AKB-9778) on blood pressure in diabetic patients and the role of VE-PTP in the regulation of eNOS activity and vascular reactivity. Methods and results In diabetic patients AKB-9778 significantly lowered systolic and diastolic blood pressure. This could be linked to elevated NO production, as AKB increased NO generation by cultured endothelial cells and elicited the NOS inhibitor-sensitive relaxation of endothelium-intact rings of mouse aorta. At the molecular level, VE-PTP inhibition increased the phosphorylation of eNOS on Tyr81 and Ser1177 (human sequence). The PIEZO1 activator Yoda1, which was used to mimic the response to shear stress, also increased eNOS Tyr81 phosphorylation, an effect that was enhanced by VE-PTP inhibition. Two kinases, i.e. abelson-tyrosine protein kinase (ABL)1 and Src were identified as eNOS Tyr81 kinases as their inhibition and down-regulation significantly reduced the basal and Yoda1-induced tyrosine phosphorylation and activity of eNOS. VE-PTP, on the other hand, formed a complex with eNOS in endothelial cells and directly dephosphorylated eNOS Tyr81 in vitro. Finally, phosphorylation of eNOS on Tyr80 (murine sequence) was found to be reduced in diabetic mice and diabetes-induced endothelial dysfunction (isolated aortic rings) was blunted by VE-PTP inhibition. Conclusions VE-PTP inhibition enhances eNOS activity to improve endothelial function and decrease blood pressure indirectly, through the activation of Tie-2 and the CD31/VE-cadherin/VEGFR2 complex, and directly by dephosphorylating eNOS Tyr81. VE-PTP inhibition, therefore, represents an attractive novel therapeutic option for diabetes-induced endothelial dysfunction and hypertension.

scholarly journals L-sepiapterin restores SLE serum-induced markers of endothelial function in endothelial cells

2019 ◽  
Vol 6 (1) ◽  
pp. e000294 ◽  
Author(s):  
Joy N Jones Buie ◽  
Dorea Pleasant Jenkins ◽  
Robin Muise-Helmericks ◽  
Jim C Oates
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Mrna Expression ◽  
Neutrophil Migration ◽  
Basal Medium ◽  
Neutrophil Adhesion ◽  
No Production ◽  
Functional Changes ◽  
Enos Mrna ◽  
The Impact

ObjectiveSLE serves as an independent risk factor` for endothelial dysfunction (ED) not explained by Framingham risk factors. We sought to understand the development of SLE-induced ED on a cellular level in order to develop strategies aimed at reversing cellular abnormalities. This study assessed the impact of SLE patient serum on endothelial nitric oxide synthase (eNOS), nitric oxide (NO) production and functional changes in the cell.MethodsHuman umbilical vein endothelial cells (HUVECs) cultured in serum of either SLE (n=25) or healthy patients (n=14) or endothelial basal medium 2 (EBM-2) culture media supplemented with fetal bovine serum with or without L-sepiapterin were used for our studies. We applied the fluorescent probe DAF-FM diacetate for intracellular NO detection using flow cytometry. Total RNA isolates were analysed using reverse transcription PCR for eNOS mRNA expression. Oxygen consumption rate was determined using seahorse analysis. Neutrophil adhesion and migration were determined using a calcein AM microscopy assay.ResultsThe mRNA expression of eNOS was increased in SLE cultured HUVECs compared with healthy control (p<0.05). The SLE eNOS mRNA level correlated with SLE patient age (p=0.008); however, this trend was not observed with healthy patients. SLE serum reduced NO production in HUVECs compared with EBM-2 cultured cells (p<0.05). Co-treatment of endothelial cells with L-sepiapterin preserved HUVEC capacity to produce NO in SLE conditions (p<0.01). SLE serum enhanced neutrophil migration (p<0.01) but not neutrophil adhesion compared with healthy controls. The bioenergetic health index was not different.ConclusionsSLE likely causes disruption of endothelial cell eNOS function and NO modulated pathways.

scholarly journals Antihypertensive Effects of Rg3-Enriched Korean Vitamin Ginseng in Spontaneously Hypertensive Rats

2020 ◽  
Vol 15 (1) ◽  
pp. 1934578X1990071
Author(s):  
Harsha Nagar ◽  
Shin Kwang Kang ◽  
Si Wan Choi ◽  
Hee-Jung Song ◽  
Su-Jeong Choi ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Endothelial Cells ◽  
Spontaneously Hypertensive Rats ◽  
Umbilical Vein ◽  
No Production ◽  
Ginsenoside Rg3 ◽  
Hypertensive Rats ◽  
Korean Red Ginseng ◽  
Spontaneously Hypertensive ◽  
Enos Phosphorylation

Ginseng is well known to treat various diseases. Ginsenoside Rg3 exhibits a variety of pharmacological activities including cardiovascular protective effects. Vitamins utilized as supplements have minimal interactions with other drugs making them attractive targets for therapeutics. Here, we prepared Rg3-enriched Korean ginseng catalyzed by vitamin (REKVG) and evaluated its ability to improve hypertension in spontaneously hypertensive rats (SHRs). The ginsenoside content in both Korean Red ginseng (KRG) and REKVG were analyzed using high-performance liquid chromatography (HPLC). Male SHRs and Wistar-Kyoto rats (WKYs) were randomly divided into 6 groups (WKY saline, WKY KRG, WKY REKVG, SHR saline, SHR KRG, and SHR REKVG). KRG and REKVG were orally administered once daily to the rats at a dose of 10 mg/kg for 6 weeks, and blood pressure was measured in live rats using the tail-cuff method. Human umbilical vein endothelial cells were used for the in vitro experiment. HPLC chromatograms revealed that the concentration of ginsenoside Rg3 in REKVG was much higher than that in KRG. The administration of REKVG significantly decreased the systolic blood pressure in SHRs at the end of 6 weeks as compared to KRG. Further, REKVG use resulted in a dose-dependent increase in Akt and endothelial nitric oxide synthase (eNOS) phosphorylation and NO production in endothelial cells. In addition, the administration of REKVG significantly increased Akt and eNOS phosphorylation and increased plasma NO levels in SHRs. We conclude that REKVG effectively lowers the blood pressure in rats and therefore could be considered for use in preventing or improving hypertension.

scholarly journals The vascular clock: a new insight into endothelial cells and pericytes crosstalk

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
V Mastrullo ◽  
R S Matos ◽  
J H McVey ◽  
P Gupta ◽  
P Madeddu ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Blood Vessels ◽  
Molecular Clock ◽  
Clock Genes ◽  
Public Institution ◽  
Perivascular Cells ◽  
Rhythmic Expression ◽  
The Impact

Abstract Background/Introduction Circadian rhythms, defined as biological oscillations with a period of circa 24h, regulate many physiological processes in the cardiovascular system, such as vascular function, vascular tone, blood pressure, heart rate and thrombus formation [1]. The vasculature responds to the main pacemaker located in the brain, but it also possesses its own clock. Indeed, a molecular clock has been identified in endothelial cells (EC) and smooth muscle cells (SMC). The disruption of the circadian clock profoundly affects cardiovascular functionality with adverse cardiovascular events such as myocardial infarction or stroke showing a 24h rhythmicity with a peak incidence in the early morning. Among several mechanisms affected by circadian dysregulation, angiogenesis plays a fundamental role in homeostasis and development of new blood vessels. EC and pericytes (PC) are the two main cell populations in the capillaries, and their physical and paracrine interaction drives and regulates the sprouting. However, the presence and the role of circadian rhythms in pericytes and whether the molecular clock affects the endothelial/pericyte interactions remain unexplored. Purpose The aim of this study is to identify a molecular clock in human vascular pericytes and elucidate the impact of the circadian clock on the formation of new blood vessels. Methods Human primary PC were synchronised and the rhythmicity of clock genes measured by luminescence, immunofluorescence, and qPCR. Synchronised PC were co-cultured with Bmal1::LUC human primary EC. The effect of PC synchronisation and circadian clock disruption by shRNA on EC clock genes and angiogenic potential were measured by luminescence and Matrigel assay, respectively. A macroporous polyurethane scaffold was developed for 3D co-cultures. Results PC presented rhythmic expression of the principal circadian genes with a circa 24h period but in our experimental setting, EC did not show circadian rhythmicity. Synchronised PC supported the rhythmic expression of the clock gene Bmal1 in EC in a contact co-culture system, suggesting a secondary form of EC molecular clock regulation. Non-contact co-cultures failed to synchronise EC. Furthermore, when the clock was disrupted in PC, their capacity to support EC's tube-forming capacity on Matrigel was impaired; clock disruption in EC did not affect angiogenesis, supporting the hypothesis that a disrupted clock in perivascular cells affects angiogenesis. In a 3D tissue engineering scaffold seeded with both EC and PC, the synchronisation of the clock led to the development of organised vascular-like structures around the scaffold's pores, as compared to the non-synchronised condition where cells appeared disorganised. Conclusion This study defines for the first time the existence of an endogenous molecular circadian clock in perivascular cells and suggests implications for circadian clock synchronisation in physiological and therapeutic angiogenesis. FUNDunding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): University of Surrey Doctoral CollegeUniversity of Surrey Bioprocess and Biochemical Engineering (BioProChem) Group.

Deferiprone increases endothelial nitric oxide synthase phosphorylation and nitric oxide production

2018 ◽  
Vol 96 (9) ◽  
pp. 879-885 ◽  
Author(s):  
Thanaporn Sriwantana ◽  
Pornpun Vivithanaporn ◽  
Kittiphong Paiboonsukwong ◽  
Krit Rattanawonsakul ◽  
Sirada Srihirun ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Endothelial Cells ◽  
Endothelial Function ◽  
Healthy Subjects ◽  
Iron Chelation ◽  
No Production ◽  
Hemoglobin E ◽  
Enos Phosphorylation

Iron chelation can improve endothelial function. However, effect on endothelial function of deferiprone has not been reported. We hypothesized deferiprone could promote nitric oxide (NO) production in endothelial cells. We studied effects of deferiprone on blood nitrite and blood pressure after single oral dose (25 mg/kg) in healthy subjects and hemoglobin E/β-thalassemia patients. Further, effects of deferiprone on NO production and endothelial NO synthase (eNOS) phosphorylation in primary human pulmonary artery endothelial cells (HPAEC) were investigated in vitro. Blood nitrite levels were higher in patients with deferiprone therapy than those without deferiprone (P = 0.023, n = 16 each). Deferiprone increased nitrite in plasma and whole blood of healthy subjects (P = 0.002 and 0.044) and thalassemia patients (P = 0.003 and 0.046) at time 180 min (n = 20 each). Asymptomatic reduction in diastolic blood pressure (P = 0.005) and increase in heart rate (P = 0.009) were observed in healthy subjects, but not in thalassemia patients. In HPAEC, deferiprone increased cellular nitrite and phospho-eNOS (Ser1177) (P = 0.012 and 0.035, n = 6) without alteration in total eNOS protein and mRNA. We conclude that deferiprone can induce NO production by enhancing eNOS phosphorylation in endothelial cells.

Crosstalk between Breast Cancer Cells and Bone Marrow Endothelium Require the Engagement of PI3K/AKT Signaling.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1299-1299
Author(s):  
Joana G. Brandao ◽  
Joao T. Barata ◽  
Raquel Nunes ◽  
Lee M. Nadler ◽  
Angelo A. Cardoso
Keyword(s):  
Breast Cancer ◽  
Bone Marrow ◽  
Endothelial Cells ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Critical Role ◽  
Metastatic Breast ◽  
Cell Types ◽  
Akt Pathway ◽  
The Impact

Abstract The presence of breast cancer cells in the patient’s bone marrow (BM) at diagnosis is associated with resistance to treatment, disease relapse and poor prognosis. Identification of the factors implicated in the homing, survival and latency of breast cancer cells in the BM should contribute to the design of more efficient therapeutic strategies for breast cancer. There is evidence that breast cancer can recruit endothelial progenitors from the BM. Also, other epithelial tumors seem to preferentially adhere to BM endothelial cells. Therefore, we hypothesized that BM endothelium may play a significant role in the biology of breast cancer cells residing in the BM. Co-cultures in Matrigel showed that breast cancer cells interact with BM endothelium to form heterotypic multicellular networks. Moreover, breast cancer cells migrate towards BM endothelium assembled as capillary-like structures, but not to structures of BM mesenchymal stem cells or BM stroma. This migration was abrogated by pertussis toxin-mediated blockade of chemokine receptor signaling, suggesting the involvement of endothelium-secreted chemokine(s). We then evaluated the impact of breast cancer cells in the survival and proliferation of BM endothelium. All breast cancer lines tested (n=4) promoted the proliferation of BM-derived endothelial cells. This effect is mediated through the engagement of the PI3K/Akt pathway (phosphorylation of Akt at Ser437 and Thr308, and activation of its downstream substrates GSK3β, PRAS-40 and FKHRL1) since its specific blockade abrogated the stimulatory effects of breast cancer on BM endothelium. We next determined whether, reciprocally, BM endothelium impacts on breast cancer cell survival. These experiments were performed in serum-free media to enhance dependency of breast cancer cells from microenvironmental stimuli. In all cases tested, BM endothelium promoted survival/proliferation of breast cancer cells. This stimulation was accompanied by the engagement of the PI3K/Akt pathway in breast cancer cells and, in three of the four lines, the phosphorylation of Erk1/2. These effects were also observed for breast cancer cells that showed constitutive activation of Akt (MCF-7 and ZR-75-1 cells). Specific blockade of PI3K/Akt abrogated the BM endothelium-promoted survival of breast cancer cells, thus demonstrating the critical role of this pathway. These studies show that crosstalk between BM endothelial cells and breast cancer cells may impact on the survival of both cell types. These findings provide new light on the mechanisms that may facilitate the development of a tumor-permissive BM microenvironment in breast cancer, and the creation of breast cancer-supporting BM niches. Importantly, this study implicates BM endothelium as a therapeutic target in breast cancer and suggest that blockade of PI3K/Akt may impact the outcome of patients with metastatic breast cancer.

scholarly journals Resistance to renal damage by chronic nitric oxide synthase inhibition in the Wistar-Furth rat

2006 ◽  
Vol 290 (1) ◽  
pp. R66-R72 ◽  
Author(s):  
Aaron Erdely ◽  
Gary Freshour ◽  
Chris Baylis
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Nitric Oxide Synthase ◽  
Renal Injury ◽  
High Dose ◽  
No Production ◽  
Sd Rat ◽  
Sd Rats ◽  
Oxide Synthase ◽  
The Impact

Chronic nitric oxide synthase inhibition (NOSI) causes chronic kidney disease (CKD) in the Sprague Dawley (SD) rat. We previously showed that the Wistar-Furth (WF) rats are resistant to several models of CKD and maintain renal nitric oxide (NO) production compared with SD rats, whereas low-dose NOSI caused progression of CKD in WF rats. Here, we evaluate the impact of high-dose chronic NOSI in WF and SD rats, as well as intrarenal responses to an acute pressor dose of NOSI in the normal WF. Rats were given NG-nitro-l-arginine methyl ester (l-NAME) (150 and 300 mg/l for 6–10 wk) in the drinking water after an initial bolus tail vein injection. Both strains showed significant reductions in total NO production with chronic l-NAME. SD given 150 mg/l l-NAME for 6 wk developed proteinuria and renal injury, whereas WF rats receiving 150 mg/l l-NAME for 6–10 wk or 300 mg/l for 6 wk developed no proteinuria and minimal renal injury. Blood pressure was significantly elevated with chronic NOSI in both strains but was higher in the SD rat. There was little impact on renal nitric oxide synthase expression with l-NAME, except that cortical endothelial nitric oxide synthase abundance increased in WF after 6 wk (150 mg/l). Micropuncture experiments with acute pressor NOSI resulted in similar increases in systemic blood pressure in SD and WF rats, whereas WF rats showed a much smaller increment in glomerular blood pressure compared with SD rats. In conclusion, WF rats do not develop renal injury after chronic NOSI at, or above, a dose that causes significant injury in the SD rat. This protection may be associated with protection from glomerular hypertension.

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