scholarly journals An Overview of NO Signaling Pathways in Aging

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4533
Author(s):  
Ali Mohammad Pourbagher-Shahri ◽  
Tahereh Farkhondeh ◽  
Marjan Talebi ◽  
Dalia M. Kopustinskiene ◽  
Saeed Samarghandian ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Cardiovascular System ◽  
Signaling Pathways ◽  
Cellular Aging ◽  
No Production ◽  
Cellular Mechanisms ◽  
Muscle Disorders ◽  
Reproduction System ◽  
No Signaling ◽  
Endothelial Nitric Oxide

Nitric Oxide (NO) is a potent signaling molecule involved in the regulation of various cellular mechanisms and pathways under normal and pathological conditions. NO production, its effects, and its efficacy, are extremely sensitive to aging-related changes in the cells. Herein, we review the mechanisms of NO signaling in the cardiovascular system, central nervous system (CNS), reproduction system, as well as its effects on skin, kidneys, thyroid, muscles, and on the immune system during aging. The aging-related decline in NO levels and bioavailability is also discussed in this review. The decreased NO production by endothelial nitric oxide synthase (eNOS) was revealed in the aged cardiovascular system. In the CNS, the decline of the neuronal (n)NOS production of NO was related to the impairment of memory, sleep, and cognition. NO played an important role in the aging of oocytes and aged-induced erectile dysfunction. Aging downregulated NO signaling pathways in endothelial cells resulting in skin, kidney, thyroid, and muscle disorders. Putative therapeutic agents (natural/synthetic) affecting NO signaling mechanisms in the aging process are discussed in the present study. In summary, all of the studies reviewed demonstrate that NO plays a crucial role in the cellular aging processes.

scholarly journals Sepiapterin improves angiogenesis of pulmonary artery endothelial cells with in utero pulmonary hypertension by recoupling endothelial nitric oxide synthase

2011 ◽  
Vol 301 (3) ◽  
pp. L334-L345 ◽  
Author(s):  
Ru-Jeng Teng ◽  
Jianhai Du ◽  
Hao Xu ◽  
Ivane Bakhutashvili ◽  
Annie Eis ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Ex Vivo ◽  
No Production ◽  
Cellular Mechanisms ◽  
Dimer Formation ◽  
Enos Activity ◽  
Endothelial Nitric Oxide

Persistent pulmonary hypertension of the newborn (PPHN) is associated with decreased blood vessel density that contributes to increased pulmonary vascular resistance. Previous studies showed that uncoupled endothelial nitric oxide (NO) synthase (eNOS) activity and increased NADPH oxidase activity resulted in marked decreases in NO bioavailability and impaired angiogenesis in PPHN. In the present study, we hypothesize that loss of tetrahydrobiopterin (BH4), a critical cofactor for eNOS, induces uncoupled eNOS activity and impairs angiogenesis in PPHN. Pulmonary artery endothelial cells (PAEC) isolated from fetal lambs with PPHN (HTFL-PAEC) or control lambs (NFL-PAEC) were used to investigate the cellular mechanisms impairing angiogenesis in PPHN. Cellular mechanisms were examined with respect to BH4 levels, GTP-cyclohydrolase-1 (GCH-1) expression, eNOS dimer formation, and eNOS-heat shock protein 90 (hsp90) interactions under basal conditions and after sepiapterin (Sep) supplementation. Cellular levels of BH4, GCH-1 expression, and eNOS dimer formation were decreased in HTFL-PAEC compared with NFL-PAEC. Sep supplementation decreased apoptosis and increased in vitro angiogenesis in HTFL-PAEC and ex vivo pulmonary artery sprouting angiogenesis. Sep also increased cellular BH4 content, NO production, eNOS dimer formation, and eNOS-hsp90 association and decreased the superoxide formation in HTFL-PAEC. These data demonstrate that Sep improves NO production and angiogenic potential of HTFL-PAEC by recoupling eNOS activity. Increasing BH4 levels via Sep supplementation may be an important therapy for improving eNOS function and restoring angiogenesis in PPHN.

The Signaling Pathways in Nitric Oxide Production by Neutrophils Exposed to N-nitrosodimethylamine

2018 ◽  
Vol 16 (2) ◽  
pp. 194-199
Author(s):  
Wioletta Ratajczak-Wrona ◽  
Ewa Jablonska
Keyword(s):  
Nitric Oxide ◽  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Polymorphonuclear Neutrophils ◽  
Microbial Pathogens ◽  
Human Neutrophils ◽  
No Production ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

Background: Polymorphonuclear neutrophils (PMNs) play a crucial role in the innate immune system’s response to microbial pathogens through the release of reactive nitrogen species, including Nitric Oxide (NO). </P><P> Methods: In neutrophils, NO is produced by the inducible Nitric Oxide Synthase (iNOS), which is regulated by various signaling pathways and transcription factors. N-nitrosodimethylamine (NDMA), a potential human carcinogen, affects immune cells. NDMA plays a major part in the growing incidence of cancers. Thanks to the increasing knowledge on the toxicological role of NDMA, the environmental factors that condition the exposure to this compound, especially its precursors- nitrates arouse wide concern. Results: In this article, we present a detailed summary of the molecular mechanisms of NDMA’s effect on the iNOS-dependent NO production in human neutrophils. Conclusion: This research contributes to a more complete understanding of the mechanisms that explain the changes that occur during nonspecific cellular responses to NDMA toxicity.

Neuregulin-1 Compensates for Endothelial Nitric Oxide Synthase Deficiency

2021 ◽  
Author(s):  
Hadis Shakeri ◽  
Jente R.A. Boen ◽  
Sofie De Moudt ◽  
Jhana O. Hendrickx ◽  
Arthur J.A. Leloup ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Cardiac Fibrosis ◽  
Separate Experiment ◽  
No Production ◽  
Ang Ii ◽  
Wild Type ◽  
Paracrine Factor ◽  
Renal Hypertrophy ◽  
Neuregulin 1 ◽  
Endothelial Nitric Oxide

Endothelial cells (ECs) secrete different paracrine signals that modulate the function of adjacent cells; two examples of these paracrine signals are nitric oxide (NO) and neuregulin-1 (NRG1), a cardioprotective growth factor. Currently, it is undetermined whether one paracrine factor can compensate for the loss of another. Herein, we hypothesized that NRG1 can compensate for endothelial NO synthase (eNOS) deficiency. Methods. We characterized eNOS null and wild type (WT) mice by cardiac ultrasound and histology and we determined circulating NRG1 levels. In a separate experiment, 8 groups of mice were divided into 4 groups of eNOS null mice and wild type (WT) mice; half of the mice received angiotensin II (Ang II) to induce a more severe phenotype. Mice were randomized to daily injections with NRG1 or vehicle for 28 days. Results. eNOS deficiency increased NRG1 plasma levels, indicating that ECs increase their NRG1 expression when NO production is deleted. eNOS deficiency also increased blood pressure, lowered heart rate, induced cardiac fibrosis, and affected diastolic function. In eNOS null mice, Ang II administration increased cardiac fibrosis, but also induced cardiac hypertrophy and renal fibrosis. NRG1 administration prevented the cardiac and renal hypertrophy and fibrosis caused by Ang II infusion and eNOS deficiency. Moreover, Nrg1 expression in the myocardium is shown to be regulated by miR-134. Conclusion. This study indicates that administration of endothelium-derived NRG1 can compensate for eNOS deficiency in the heart and kidneys.

Hypothermia-induced cardioprotection using extended ischemia and early reperfusion cooling

2007 ◽  
Vol 292 (4) ◽  
pp. H1995-H2003 ◽  
Author(s):  
Zuo-Hui Shao ◽  
Wei-Tien Chang ◽  
Kim Chai Chan ◽  
Kim R. Wojcik ◽  
Chin-Wang Hsu ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Protein Kinase ◽  
Therapeutic Hypothermia ◽  
Optimal Timing ◽  
No Production ◽  
Early Reperfusion ◽  
No Signaling ◽  
Nos Inhibitor ◽  
Oxide Synthase ◽  
Pkc Activation

Optimal timing of therapeutic hypothermia for cardiac ischemia is unknown. Our prior work suggests that ischemia with rapid reperfusion (I/R) in cardiomyocytes can be more damaging than prolonged ischemia alone. Also, these cardiomyocytes demonstrate protein kinase C (PKC) activation and nitric oxide (NO) signaling that confer protection against I/R injury. Thus we hypothesized that hypothermia will protect most using extended ischemia and early reperfusion cooling and is mediated via PKC and NO synthase (NOS). Chick cardiomyocytes were exposed to an established model of 1-h ischemia/3-h reperfusion, and the same field of initially contracting cells was monitored for viability and NO generation. Normothermic I/R resulted in 49.7 ± 3.4% cell death. Hypothermia induction to 25°C was most protective (14.3 ± 0.6% death, P < 0.001 vs. I/R control) when instituted during extended ischemia and early reperfusion, compared with induction after reperfusion (22.4 ± 2.9% death). Protection was completely lost if onset of cooling was delayed by 15 min of reperfusion (45.0 ± 8.2% death). Extended ischemia/early reperfusion cooling was associated with increased and sustained NO generation at reperfusion and decreased caspase-3 activation. The NOS inhibitor Nω-nitro-l-arginine methyl ester (200 μM) reversed these changes and abrogated hypothermia protection. In addition, the PKCε inhibitor myr-PKCε v1-2 (5 μM) also reversed NO production and hypothermia protection. In conclusion, therapeutic hypothermia initiated during extended ischemia/early reperfusion optimally protects cardiomyocytes from I/R injury. Such protection appears to be mediated by increased NO generation via activation of protein kinase Cε; nitric oxide synthase.

scholarly journals Induction and stability of human Th17 cells require endogenous NOS2 and cGMP-dependent NO signaling

2013 ◽  
Vol 210 (7) ◽  
pp. 1433-1445 ◽  
Author(s):  
Nataša Obermajer ◽  
Jeffrey L. Wong ◽  
Robert P. Edwards ◽  
Kong Chen ◽  
Melanie Scott ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
T Cells ◽  
Cd4 T Cells ◽  
Th17 Cells ◽  
De Novo ◽  
Inflammatory Diseases ◽  
Suppressor Cells ◽  
Guanosine Monophosphate ◽  
No Production ◽  
No Signaling

Nitric oxide (NO) is a ubiquitous mediator of inflammation and immunity, involved in the pathogenesis and control of infectious diseases, autoimmunity, and cancer. We observed that the expression of nitric oxide synthase-2 (NOS2/iNOS) positively correlates with Th17 responses in patients with ovarian cancer (OvCa). Although high concentrations of exogenous NO indiscriminately suppress the proliferation and differentiation of Th1, Th2, and Th17 cells, the physiological NO concentrations produced by patients’ myeloid-derived suppressor cells (MDSCs) support the development of RORγt(Rorc)+IL-23R+IL-17+ Th17 cells. Moreover, the development of Th17 cells from naive-, memory-, or tumor-infiltrating CD4+ T cells, driven by IL-1β/IL-6/IL-23/NO-producing MDSCs or by recombinant cytokines (IL-1β/IL-6/IL-23), is associated with the induction of endogenous NOS2 and NO production, and critically depends on NOS2 activity and the canonical cyclic guanosine monophosphate (cGMP)–cGMP-dependent protein kinase (cGK) pathway of NO signaling within CD4+ T cells. Inhibition of NOS2 or cGMP–cGK signaling abolishes the de novo induction of Th17 cells and selectively suppresses IL-17 production by established Th17 cells isolated from OvCa patients. Our data indicate that, apart from its previously recognized role as an effector mediator of Th17-associated inflammation, NO is also critically required for the induction and stability of human Th17 responses, providing new targets to manipulate Th17 responses in cancer, autoimmunity, and inflammatory diseases.

scholarly journals Protein kinase Cδ regulates endothelial nitric oxide synthase expression via Akt activation and nitric oxide generation

2008 ◽  
Vol 294 (3) ◽  
pp. L582-L591 ◽  
Author(s):  
Neetu Sud ◽  
Stephen Wedgwood ◽  
Stephen M. Black
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Promoter Activity ◽  
Dominant Negative ◽  
No Production ◽  
Enos Expression ◽  
Akt Activation ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

In this study, we explore the roles of the delta isoform of PKC (PKCδ) in the regulation of endothelial nitric oxide synthase (eNOS) activity in pulmonary arterial endothelial cells isolated from fetal lambs (FPAECs). Pharmacological inhibition of PKCδ with either rottlerin or with the peptide, δV1-1, acutely attenuated NO production, and this was associated with a decrease in phosphorylation of eNOS at Ser1177 (S1177). The chronic effects of PKCδ inhibition using either rottlerin or the overexpression of a dominant negative PKCδ mutant included the downregulation of eNOS gene expression that was manifested by a decrease in both eNOS promoter activity and protein expression after 24 h of treatment. We also found that PKCδ inhibition blunted Akt activation as observed by a reduction in phosphorylated Akt at position Ser473. Thus, we conclude that PKCδ is actively involved in the activation of Akt. To determine the effect of Akt on eNOS signaling, we overexpressed a dominant negative mutant of Akt and determined its effect of NO generation, eNOS expression, and phosphorylation of eNOS at S1177. Our results demonstrated that Akt inhibition was associated with decreased NO production that correlated with reduced phosphorylation of eNOS at S1177, and decreased eNOS promoter activity. We next evaluated the effect of endogenously produced NO on eNOS expression by incubating FPAECs with the eNOS inhibitor 2-ethyl-2-thiopseudourea (ETU). ETU significantly inhibited NO production, eNOS promoter activity, and eNOS protein levels. Together, our data indicate involvement of PKCδ-mediated Akt activation and NO generation in maintaining eNOS expression.

Effects of homocysteine on endothelial nitric oxide production

2000 ◽  
Vol 279 (4) ◽  
pp. F671-F678 ◽  
Author(s):  
Xiaohui Zhang ◽  
Hong Li ◽  
Haoli Jin ◽  
Zachary Ebin ◽  
Sergey Brodsky ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Redox State ◽  
Calcium Ionophore ◽  
No Production ◽  
Cellular Redox ◽  
A Cell ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Peroxynitrite Scavengers

Hyperhomocysteinemia (HHCy) is an independent and graded cardiovascular risk factor. HHCy is prevalent in patients with chronic renal failure, contributing to the increased mortality rate. Controversy exists as to the effects of HHCy on nitric oxide (NO) production: it has been shown that HHCy both increases and suppresses it. We addressed this problem by using amperometric electrochemical NO detection with a porphyrinic microelectrode to study responses of endothelial cells incubated with homocysteine (Hcy) to the stimulation with bradykinin, calcium ionophore, or l-arginine. Twenty-four-hour preincubation with Hcy (10, 20, and 50 μM) resulted in a gradual decline in responsiveness of endothelial cells to the above stimuli. Hcy did not affect the expression of endothelial nitric oxide synthase (eNOS), but it stimulated formation of superoxide anions, as judged by fluorescence of dichlorofluorescein, and peroxynitrite, as detected by using immunoprecipitation and immunoblotting of proteins modified by tyrosine nitration. Hcy did not directly affect the ability of recombinant eNOS to generate NO, but oxidation of sulfhydryl groups in eNOS reduced its NO-generating activity. Addition of 5-methyltetrahydrofolate restored NO responses to all agonists tested but affected neither the expression of the enzyme nor formation of nitrotyrosine-modified proteins. In addition, a scavenger of peroxynitrite or a cell-permeant superoxide dismutase mimetic reversed the Hcy-induced suppression of NO production by endothelial cells. In conclusion, electrochemical detection of NO release from cultured endothelial cells demonstrated that concentrations of Hcy >20 μM produce a significant indirect suppression of eNOS activity without any discernible effects on its expression. Folates, superoxide ions, and peroxynitrite scavengers restore the NO-generating activity to eNOS, collectively suggesting that cellular redox state plays an important role in HCy-suppressed NO-generating function of this enzyme.

Endothelin stimulates endothelial nitric oxide synthase expression in the thick ascending limb

2004 ◽  
Vol 287 (2) ◽  
pp. F231-F235 ◽  
Author(s):  
Marcela Herrera ◽  
Jeffrey L. Garvin
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Receptor Antagonist ◽  
Endothelial Nitric Oxide Synthase ◽  
No Production ◽  
Thick Ascending Limb ◽  
Enos Expression ◽  
No Release ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Endothelin-1 (ET-1) acutely inhibits NaCl reabsorption by the thick ascending limb (THAL) by activating the ETB receptor, stimulating endothelial nitric oxide synthase (eNOS), and releasing nitric oxide (NO). In nonrenal tissue, chronic exposure to ET-1 stimulates eNOS expression via the ETB receptor and activation of phosphatidylinositol 3-kinase (PI3K). We hypothesized that ET-1 increases eNOS expression in the THAL by binding to ETB receptors and stimulating PI3K. In primary cultures of medullary THALs treated for 24 h, eNOS expression increased by 36 ± 18% with 0.01 nM ET-1, 123 ± 30% with 0.1 nM ( P < 0.05; n = 5), and 71 ± 30% with 1 nM, whereas 10 nM had no effect. BQ-788, a selective ETB receptor antagonist, completely blocked stimulation of eNOS expression caused by 0.1 nM ET-1 (12 ± 25 vs. 120 ± 40% for ET-1 alone; P < 0.05; n = 5). BQ-123, a selective ETA receptor antagonist, did not affect the increase in eNOS caused by 0.1 nM ET-1. Sarafotoxin c (S6c; 0.1 μM), a selective ETB receptor agonist, increased eNOS expression by 77 ± 30% ( P < 0.05; n = 6). Wortmannin (0.01 μM), a PI3K inhibitor, completely blocked the stimulatory effect of 0.1 μM S6c (77 ± 30 vs. −28 ± 9%; P < 0.05; n = 6). To test whether the increase in eNOS expression heightens activity, we measured NO release in response to simultaneous treatment with l-arginine, ionomycin, and clonidine using a NO-sensitive electrode. NO release by control cells was 337 ± 61 and 690 ± 126 pA in ET-1-treated cells ( P < 0.05; n = 5). Taken together, these data suggest that ET-1 stimulates THAL eNOS, activating ETB receptors and PI3K and thereby increasing NO production.

scholarly journals Nitric oxide function in atherosclerosis

1997 ◽  
Vol 6 (1) ◽  
pp. 3-21 ◽  
Author(s):  
K. E. Matthys ◽  
H. Bult
Keyword(s):  
Nitric Oxide ◽  
Leukocyte Adhesion ◽  
Atherosclerotic Lesion ◽  
Vascular Wall ◽  
Early Event ◽  
No Production ◽  
Oxygen Intermediates ◽  
Atherosclerotic Lesions ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Atherosclerosis is a chronic inflammatory process in the intima of conduit arteries, which disturbs the endothelium-dependent regulation of the vascular tone by the labile liposoluble radical nitric oxide (NO) formed by the constitutive endothelial nitric oxide synthase (eNOS). This defect predisposes to coronary vasospasm and cardiac ischaemia, with anginal pain as the typical clinical manifestation. It is now appreciated that endothelial dysfunction is an early event in atherogenesis and that it may also involve the microcirculation, in which atherosclerotic lesions do not develop. On the other hand, the inflammatory environment in atherosclerotic plaques may result in the expression of the inducible NO synthase (iNOS) isozyme. Whether the dysfunction in endothelial NO production is causal to, or the result of, atherosclerotic lesion formation is still highly debated. Most evidence supports the hypothesis that constitutive endothelial NO release protects against atherogenesis e.g. by preventing smooth muscle cell proliferation and leukocyte adhesion. Nitric oxide generated by the inducible isozyme may be beneficial by replacing the failing endothelial production but excessive release may damage the vascular wall cells, especially in combination with reactive oxygen intermediates.

scholarly journals Cilostazol Induces eNOS and TM Expression via Activation with Sirtuin 1/Krüppel-like Factor 2 Pathway in Endothelial Cells

2021 ◽  
Vol 22 (19) ◽  
pp. 10287
Author(s):  
Chih-Hsien Wu ◽  
Yi-Lin Chiu ◽  
Chung-Yueh Hsieh ◽  
Guo-Shiang Tsung ◽  
Lian-Shan Wu ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Endothelial Nitric Oxide Synthase ◽  
Umbilical Vein ◽  
Sirtuin 1 ◽  
No Production ◽  
Beneficial Effects ◽  
Umbilical Vein Endothelial Cells ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Cilostazol was suggested to be beneficial to retard in-stent atherosclerosis and prevent stent thrombosis. However, the mechanisms responsible for the beneficial effects of cilostazol are not fully understood. In this study, we attempted to verify the mechanism of the antithrombotic effect of cilostazol. Human umbilical vein endothelial cells (HUVECs) were cultured with various concentrations of cilostazol to verify its impact on endothelial cells. KLF2, silent information regulator transcript-1 (SIRT1), endothelial nitric oxide synthase (eNOS), and endothelial thrombomodulin (TM) expression levels were examined. We found cilostazol significantly activated KLF2 expression and KLF2-related endothelial function, including eNOS activation, Nitric oxide (NO) production, and TM secretion. The activation was regulated by SIRT1, which was also stimulated by cilostazol. These findings suggest that cilostazol may be capable of an antithrombotic and vasculoprotective effect in endothelial cells.

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