Erythropoietin activates nitric oxide synthase in murine erythrocytes

Mihov, Deyan; Vogel, Johannes; Gassmann, Max; Bogdanova, Anna

doi:10.1152/ajpcell.00543.2008

Cited by 51 publications

(52 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…6,12 Activity of a red cell NOS may be involved in the regulation of RBC lifespan, 41 deformability, 16,42,43 and potentially red cell velocity and blood flow. 43 This notion is in line with previous findings showing that NOS inhibitors abolish the antiplatelet effects of RBCs in vitro 15,16 and decrease the level of NO products released by isolated RBCs, 16,24 however do not affect intracellular nitrite concentrations. 44 Thus RBCs may also contribute to vascular homeostasis, independent of their "classic role" as transporters of oxygen, energy substrates and nutrients.…”

Section: Origin Of Constitutive No Synthesis Within Rbcssupporting

confidence: 88%

“…22 RBCs have been shown to express a protein containing epitopes of an eNOS. 6,15,16,20,[23][24][25] However, positive staining with anti-iNOS antibodies has also been reported, 20,25 and others suggested that RBCs might express a novel NOS isoform. 23,25 Thus, doubts about the functional significance of the NOS-like activity in RBCs remain, and little is known about NOS isoform identity and disease relevance.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Human red blood cells at work: identification and visualization of erythrocytic eNOS activity in health and disease

Cortese‐Krott

Rodriguez-Mateos

Sansone

et al. 2012

Blood

162

120

View full text Add to dashboard Cite

IntroductionThe key event in the pathogenesis of arteriosclerosis is believed to be a dysfunction of the endothelium with disruption of vascular homeostasis, predisposing blood vessels to vasoconstriction, inflammation, leukocyte adhesion, thrombosis, and proliferation of vascular smooth muscle cells. Red blood cells (RBCs) are typically considered as shuttles of respiratory gases and nutrients for tissues, less so compartments important to vascular integrity. Patients with coronary artery disease (CAD) and concomitant anemia have a poorer prognosis after myocardial infarction, percutaneous coronary intervention, and coronary artery bypass grafting, and are more prone to developing heart failure with fatal outcomes. [1][2][3] Surprisingly, erythropoietin treatment fails to improve diagnosis, indicating that a compromised gas exchange/nutrient transport capacity of blood is insufficient to explain this outcome.Nitric oxide (NO) is an essential short-lived signaling/ regulatory product of a healthy endothelium that is critically important for vascular health. Decreased production and/or bioactivity of NO are a hallmark of endothelial dysfunction and have been shown to contribute to accelerated atherogenesis. In the cardiovascular system, NO is continuously produced in endothelial cells (ECs) by the type III isoform of NO synthase (eNOS, NOS3; EC 1.14.13.39). 4 In addition to endothelial cells, some circulating blood cells also contain eNOS.It is an accepted dogma that RBCs take up and inactivate endothelium-derived NO via rapid reaction with oxyhemoglobin to form methemoglobin and nitrate, thereby limiting NO available for vasodilatation. Yet it has also been shown that RBCs not only act as "NO sinks" but synthesize, store, and transport NO metabolic products. Under hypoxic conditions in particular, it has been demonstrated that RBCs induce NO-dependent vasorelaxation. 5,6 Mechanisms of release and potential sources of NO in RBCs are still a matter of debate, but candidates include iron-nitrosylhemoglobin, 7 S-nitrosohemoglobin, [8][9][10] and nitrite. The latter may form NO either via deoxyhemoglobin 5,11 or xanthine oxidoreductase (XOR)-mediated reduction, 6,12 or via spontaneous 12 and carbonic anhydrase-facilitated disproportionation. 13 Most of these processes show a clear oxygen-dependence, and several are favored by low oxygen tensions. The relative contribution of either mechanism to NO formation varies with oxygen partial pressure along the vascular tree. In addition, RBCs release ATP when subjected to hypoxia, providing an alternative vasodilatory pathway. 14 The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked ''advertisement'' in accordance with 18 USC section 1734. 16,19 and citrulline 15,18 in the supernatant. However, Kang et al failed to measure citrulline production in RBC lysates, 20 maybe because of loss of cellular structures or cofactors important for activity. 21 Another recent study fai...

show abstract

Section: Origin Of Constitutive No Synthesis Within Rbcssupporting

confidence: 88%

mentioning

confidence: 99%

Human red blood cells at work: identification and visualization of erythrocytic eNOS activity in health and disease

Cortese‐Krott

Rodriguez-Mateos

Sansone

et al. 2012

Blood

162

120

View full text Add to dashboard Cite

show abstract

“…The results obtained indicate that IL-6 is an essential regulator of EPO gene expression and possibly of HIF-1a during acute-phase conditions mainly in hepatocytes, in spite of an increase of HIF-2a that turned out not to be affected by the loss of IL-6. Recent findings supporting antioxidant 19 and protective functions 20 of EPO seem to match with our observations, identifying EPO as one more weapon in the arsenal of the antioxidant and protective cellular mechanism that responds to injury and environmental stresses.…”

supporting

confidence: 90%

Cellular and molecular mechanisms regulating the hepatic erythropoietin expression during acute-phase response: a role for IL-6

Ramadori

Ahmad

Ramadori

2010

Laboratory Investigation

View full text Add to dashboard Cite

The source of circulating erythropoietin (EPO), the mediators and the mechanisms involved in the upregulation of EPO gene expression during acute-phase reaction are still poorly understood. Acute-phase reaction was induced by either intramuscular turpentine oil (TO) or intraperitoneal lipopolysaccharide (LPS) administration into wild-type and interleukin (IL)-6 knockout (KO) mice. Animals were killed at different time points and blood, liver and muscle tissue were collected. Serum levels of EPO were measured by enzyme-linked immunoadsorbent assay; liver and injured muscle samples were processed for RNA isolation and for protein analysis. EPO, hypoxia-inducible factors 1a and 2a (HIF-1a and HIF-2a) mRNA were analyzed by RT-PCR and the protein levels were analyzed by western blot and electrophoretic mobility shift assay. HIF-1a and HIF-2a localization was performed through immunofluorescence staining. EPO, HIF-1 and HIF-2 gene and protein expression levels were also analyzed in isolated mouse hepatocytes after stimulation with IL-6. In the wild-type animals, EPO serum levels increased dramatically at 12 h after the insults together with the hepatic gene expression. In TO-treated animals, the EPO gene expression reached an 8.2-fold increase at 12 h, and in LPS-treated mice a similar induction was recorded at 6 h (about 4.5-fold increase). In the IL-6KO strain, the upregulation after the inflammatory stimuli was much lower (only 2.0-fold increase). A progressive upregulation of HIF-1a and HIF-2a was detectable until 6 h after the insults, but only HIF-1a upregulation was reduced in IL-6KO mice. In isolated hepatocytes, stimulation with a single dose of IL-6 induced a nuclear accumulation of HIF-1a, in parallel with an increase of EPO mRNA. No effect on HIF-2a expression was found. IL-6 appears to be the main regulator of EPO gene expression and a major contributor for HIF-1a induction in hepatocytes and Kupffer cells during acute-phase response. The increase of HIF-2a, predominantly expressed in endothelial cells and fibroblast-like cells, seems not to be affected by the lack of IL-6.

show abstract

“…On this basis, and since it has been shown that the use of EPO might lead to higher RBC-derived NO levels [55,56], one might speculate that the EPO treatment used to break down the anemic state in ESRD patients might be one of the mechanisms involved in the increased RBC-NOS activity observed. To this end we performed some experiments in which RBC-NOS expression and activation of it by phosphorylation in ESRD-RBCs proved comparable among patients treated with EPO or not (ph-eNOS: DM.F.I.…”

Section: Discussionmentioning

confidence: 99%

Nitric oxide synthetic pathway and cGMP levels are altered in red blood cells from end-stage renal disease patients

et al. 2016

View full text Add to dashboard Cite

Red blood cells (RBCs) enzymatically produce nitric oxide (NO) by a functional RBC-nitric oxide synthase (RBC-NOS). NO is a vascular key regulatory molecule. In RBCs its generation is complex and influenced by several factors, including insulin, acetylcholine, and calcium. NO availability is reduced in end-stage renal disease (ESRD) and associated with endothelial dysfunction. We previously demonstrated that, through increased phosphatidylserine membrane exposure, ESRD-RBCs augmented their adhesion to human cultured endothelium, in which NO bioavailability decreased. Since RBC-NOS-dependent NO production in ESRD is unknown, this study aimed to investigate RBC-NOS levels/activation, NO production/bioavailability in RBCs from healthy control subjects (C, N = 18) and ESRD patients (N = 27). Although RBC-NOS expression was lower in ESRDRBCs, NO, cyclic guanosine monophosphate (cGMP), RBC-NOS Serine1177 phosphorylation level and eNOS/ Calmodulin (CaM)/Heat Shock Protein-90 (HSP90) interaction levels were higher in ESRD-RBCs, indicating increased enzyme activation. Conversely, following RBCs stimulation with insulin or ionomycin, NO and cGMP levels were significantly lower in ESRD-than in C-RBCs, suggesting that uremia might reduce the RBC-NOS response to further stimuli. Additionally, the activity of multidrug-resistance-associated protein-4 (MRP4; cGMPmembrane transporter) was significantly lower in ESRDRBCs, suggesting a possible compromised efflux of cGMP across the ESRD-RBCs membrane. This study for the first time showed highest basal RBC-NOS activation in ESRDRBCs, possibly to reduce the negative impact of decreased NOS expression. It is further conceivable that high NO production only partially affects cell function of ESRDRBCs maybe because in vivo they are unable to respond to physiologic stimuli, such as calcium and/or insulin.Keywords End-stage renal disease Á Red blood cells Á Nitric oxide Á cGMP Á Nitric oxide synthase Mario Bonomini, and Assunta Pandolfi have contributed equally to the study.Electronic supplementary material The online version of this article

show abstract

Erythropoietin activates nitric oxide synthase in murine erythrocytes

Cited by 51 publications

References 61 publications

Human red blood cells at work: identification and visualization of erythrocytic eNOS activity in health and disease

Human red blood cells at work: identification and visualization of erythrocytic eNOS activity in health and disease

Cellular and molecular mechanisms regulating the hepatic erythropoietin expression during acute-phase response: a role for IL-6

Nitric oxide synthetic pathway and cGMP levels are altered in red blood cells from end-stage renal disease patients

Contact Info

Product

Resources

About