scholarly journals Endothelial cell respiration is affected by the oxygen tension during shear exposure: role of mitochondrial peroxynitrite

2008 ◽  
Vol 295 (1) ◽  
pp. C180-C191 ◽  
Author(s):  
Charles I. Jones ◽  
Zhaosheng Han ◽  
Tennille Presley ◽  
Saradhadevi Varadharaj ◽  
Jay L. Zweier ◽  
...  

Cultured vascular endothelial cell (EC) exposure to steady laminar shear stress results in peroxynitrite (ONOO−) formation intramitochondrially and inactivation of the electron transport chain. We examined whether the “hyperoxic state” of 21% O2, compared with more physiological O2 tensions (Po2), increases the shear-induced nitric oxide (NO) synthesis and mitochondrial superoxide (O2·−) generation leading to ONOO− formation and suppression of respiration. Electron paramagnetic resonance oximetry was used to measure O2 consumption rates of bovine aortic ECs sheared (10 dyn/cm2, 30 min) at 5%, 10%, or 21% O2 or left static at 5% or 21% O2. Respiration was inhibited to a greater extent when ECs were sheared at 21% O2 than at lower Po2 or left static at different Po2. Flow in the presence of an endothelial NO synthase (eNOS) inhibitor or a ONOO− scavenger abolished the inhibitory effect. EC transfection with an adenovirus that expresses manganese superoxide dismutase in mitochondria, and not a control virus, blocked the inhibitory effect. Intracellular and mitochondrial O2·− production was higher in ECs sheared at 21% than at 5% O2, as determined by dihydroethidium and MitoSOX red fluorescence, respectively, and the latter was, at least in part, NO-dependent. Accumulation of NO metabolites in media of ECs sheared at 21% O2 was modestly increased compared with ECs sheared at lower Po2, suggesting that eNOS activity may be higher at 21% O2. Hence, the hyperoxia of in vitro EC flow studies, via increased NO and mitochondrial O2·− production, leads to enhanced ONOO− formation intramitochondrially and suppression of respiration.

1991 ◽  
Vol 260 (6) ◽  
pp. H1992-H1996 ◽  
Author(s):  
H. Jo ◽  
R. O. Dull ◽  
T. M. Hollis ◽  
J. M. Tarbell

Altered permeability of vascular endothelium to macromolecules may play a role in vascular disease as well as vascular homeostasis. Because the shear stress of flowing blood on the vascular wall is known to influence many endothelial cell properties, an in vitro system to measure transendothelial permeability (Pe) to fluorescein isothiocyanate conjugated bovine serum albumin under defined physiological levels of steady laminar shear stress was developed. Bovine aortic endothelial cells grown on polycarbonate filters pretreated with gelatin and fibronectin constituted the model system. Onset of 1 dyn/cm2 shear stress resulted in a Pe rise from 5.1 +/- 1.3 x 10(-6) cm/s to 21.9 +/- 4.6 X 10(-6) cm/s at 60 min (n = 6); while 10 dyn/cm2 shear stress increased Pe from 4.8 +/- 1.5 X 10(-6) cm/s to 50.2 +/- 6.8 X 10(-6) cm/s at 30 min and 49.6 +/- 8.9 X 10(-6) cm/s at 60 (n = 9). Pe returned to preshear values within 120 and 60 min after removal of 1 and 10 dyn/cm2 shear stress, respectively. The data show that endothelial cell Pe in vitro is acutely sensitive to shear stress.


1986 ◽  
Vol 83 (7) ◽  
pp. 2114-2117 ◽  
Author(s):  
P. F. Davies ◽  
A. Remuzzi ◽  
E. J. Gordon ◽  
C. F. Dewey ◽  
M. A. Gimbrone

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Ishita Chatterjee ◽  
Kishore K Wary

Rationale: A recent genome-wide association study (GWAS) has linked a frequently occurring variation in the LPP3 (also known as PPAP2b) loci to increased risk of coronary heart disease (CAD). However, the in vivo function of LPP3 in vascular endothelial cell is incompletely understood. Goal: To address the endothelial cell (EC) specific function of Lpp3 in mice. Results: Tie-2/Cre mediated Lpp3 deletion did not affect normal vasculogenesis in early embryonic development, in contrast, in late embryonic stages it led to impaired angiogenesis associated with hemorrhage, edema and late embryonic lethal phenotype. Immunohistochemical staining followed by microscopic analyses of mutant embryos revealed reduced fibronectin and VE-cadherin expression throughout different vascular bed, and increased apoptosis in CD31+ vascular structures. Transmission electron microscopy (TEM) showed the presence of apoptotic endothelial cells and disruption of adherens junctions in mutant embryos. LPP3-knockdown in vitro showed an increase in p53 and p21 protein levels, with concomitant decrease in cell proliferation. LPP3-knockdown also decreased transendothelial electrical resistance (TER), interestingly re-expression of ß-catenin cDNA into LPP3-depleted endothelial cells partially restored the effect of loss of LPP3. Conclusion: These results suggest the ability of LPP3 to regulate survival and apoptotic activities of endothelial cells during patho/physiological angiogenesis.


2008 ◽  
Vol 1136 ◽  
Author(s):  
Jing Lu ◽  
Dongwoo Khang ◽  
Thomas J. Webster

ABSTRACTTo study the contribution of different surface feature properties in improving vascular endothelial cell adhesion, rationally designed nano/sub-micron patterns with various dimensions were created on titanium surfaces in this study. In vitro results indicated that endothelial cell adhesion was improved when the titanium pattern dimensions decreased into the nano-scale. Specifically, endothelial cells preferred to adhere on sub-micron and nano rough titanium substrates compared to flat titanium. Moreover, titanium with nano and sub-micron roughness and with the same chemistry as compared to flat titanium, had significantly greater surface energy. Thus, the present study indicated the strong potential of surface nanotopography and nano/sub-micron roughness for improving current vascular stent design.


2018 ◽  
Vol 116 (2) ◽  
pp. 546-555 ◽  
Author(s):  
Qing Lyu ◽  
Suowen Xu ◽  
Yuyan Lyu ◽  
Mihyun Choi ◽  
Christine K. Christie ◽  
...  

SENCR is a human-specific, vascular cell-enriched long-noncoding RNA (lncRNA) that regulates vascular smooth muscle cell and endothelial cell (EC) phenotypes. The underlying mechanisms of action of SENCR in these and other cell types is unknown. Here, levels of SENCR RNA are shown to be elevated in several differentiated human EC lineages subjected to laminar shear stress. Increases in SENCR RNA are also observed in the laminar shear stress region of the adult aorta of humanized SENCR-expressing mice, but not in disturbed shear stress regions. SENCR loss-of-function studies disclose perturbations in EC membrane integrity resulting in increased EC permeability. Biotinylated RNA pull-down and mass spectrometry establish an abundant SENCR-binding protein, cytoskeletal-associated protein 4 (CKAP4); this ribonucleoprotein complex was further confirmed in an RNA immunoprecipitation experiment using an antibody to CKAP4. Structure–function studies demonstrate a noncanonical RNA-binding domain in CKAP4 that binds SENCR. Upon SENCR knockdown, increasing levels of CKAP4 protein are detected in the EC surface fraction. Furthermore, an interaction between CKAP4 and CDH5 is enhanced in SENCR-depleted EC. This heightened association appears to destabilize the CDH5/CTNND1 complex and augment CDH5 internalization, resulting in impaired adherens junctions. These findings support SENCR as a flow-responsive lncRNA that promotes EC adherens junction integrity through physical association with CKAP4, thereby stabilizing cell membrane-bound CDH5.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Satyanarayana Alleboina ◽  
Madhu V Singh ◽  
Thomas Wong ◽  
Ayotunde Dokun

Abstract Peripheral artery disease (PAD) is atherosclerotic occlusion of vessel outside the heart and most commonly affects the lower extremities. Diabetes (DM) accelerates the course and severity of PAD. Studies have shown that vascular endothelial cell NF-κB activity is required for post ischemic adaptation in experimental PAD. To better understand how DM contributes to PAD severity, we investigated the role of DM hyperglycemia in the activation of NF-κB under ischemic conditions. Induced ischemia in human vascular endothelial cell (HUVEC) cultures increased components of both canonical and non-canonical NF-κB pathways in the nucleus (p65 1.0 ± 0.1 vs 1.5 ± 0.2, p< 0.05, RelB 1.0 ± 0.1 vs 1.5 ± 0.2, p<0.01). Similarly, HUVEC acutely exposed to high glucose (HG, 25 mM) activated both canonical (IκB-α degradation, normal vs. HG 1.25 ± 0.02 vs 0.9 ± 0.0, p<0.05) and non-canonical NF-κB (p100 degradation, normal vs HG 0.021±0.001 vs 0.016±0.000, p<0.05) pathways. Prolonged exposure (3 days) of HUVEC to high glucose before ischemia resulted in impaired NF-κB activation as evident from decreased IκB phosphorylation (pIκB/IκB in normal glucose and ischemia 1.56 ± 0.22 vs 1.12 ± 0.35, p<0.01). To understand the signaling pathways underlying the ischemic activation of the NF-κB pathway, we used an array of antibodies to phosphoproteins involved in the inflammatory pathway. Compared to the lysates from cells grown in normal glucose, the lysates from cells grown in prolonged high glucose had dramatically increased phosphorylation of PKC-β2 (PKC-β2pSer661, 8-fold increase). To test whether this increase in PKC-β2pSer66 impairs NF-κB activation by ischemia, we treated HUVECS with prolonged high glucose exposure and ruboxystaurin (Rbx) (20 nM), an inhibitor of PKC-β2 phosphorylation, prior to ischemic exposure. Immunoblotting results confirmed that inhibition of PKC-β2 phosphorylation enhanced the ischemia induced NF-κB activation in HUVEC in this condition. We then tested the effect of Rbx on PKC-β2 phosphorylation and NF-κB activation in vivo in Akita mice, a model for type 1 diabetes. Consistent with our in vitro findings, in experimental PAD, NF-κB activity in the ischemic hind limb of Akita mice was significantly lower than those of the wild type (WT) mice as measured by IκB-α degradation (WT ischemic vs Akita ischemic; 0.04 ± 0.03 vs 0.10 ± 0.04 p<0.05). However, treatment of Akita mice with Rbx increased NF-κB activation in the ischemic hind limb (Akita ischemic 0.10 ± 0.04 vs ischemic+ Rbx 0.05 ± 0.02, p<0.05). Moreover, compared to the WT mice, the untreated Akita mice showed an impaired perfusion in the ischemic limbs (% perfusion recovery, WT vs Akita; 80.1 ± 10.3 vs 55.7 ± 10.1, p<0.05, n=5-8) that was improved in Rbx treated Akita mice (96.3 ± 2.3, p<0.01). Thus, hyperglycemic conditions increase PKC-β2pSer66 in endothelial cells attenuating salutary NF-κB activation contributing to poor PAD outcomes in DM.


2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Junyao Yang ◽  
Wen Wang ◽  
Qian Wang ◽  
Lingfang Zeng

Background: Histone deacetylase 7 (HDAC7) belongs to class II HDAC family, playing a pivotal role in the maintenance of endothelium integrity. There are 8 splicing variants in mouse HDAC7 mRNAs. Within the 5’ terminal non-coding area of some variants, there exist some short open reading frames (sORFs). Whether these sORFs can be translated and their potential roles in cellular physiology remain unclear. Method and results: Our previous studies suggested that one mouse HDAC7 produced a 7aa peptide from the non-coding area. In this study, we demonstrated that one sORF encoding a 7 amino acids (aa)-peptide could be translated in response to vascular endothelial cell growth factor (VEGF) in vascular progenitor cells (VPCs). The 7aa-peptide (7A) could be phosphorylated at serine residue via MEKK1. Importantly, the phosphorylated 7aa-peptide (7Ap) could transfer the phosphorylation group to the Thr residue of the 14-3-3γ protein in a cell free in-gel buffer system. The in vitro functional analyses revealed that 7A enhanced VEGF-induced VPC migration and differentiation toward endothelial cell (EC) lineage, in which MEKK1 and 14-3-3γ served as upstream kinase and downstream effector respectively. Knockdown of either MEKK1 or 14-3-3γ attenuated VEGF-induced VPC migration and differentiation. Exogenous 7Ap could rescue VEGF effect in MEKK1 but not in 14-3-3γ knockdown cells. The in vivo studies showed that 7A especially 7Ap induced capillary vessel formation within matrigel plug assays, increased re-endothelialization and suppressed neointima formation in the femoral artery injury model, and promoted the foot blood perfusion recovery in the hindlimb ischemia model. Conclusion: These results indicate that the sORFs within the non-coding area can be translated under some circumstances and that the 7aa-peptide may play an important role in cellular processes like migration and differentiation via acting as a phosphorylation carrier. Significance: As a phosphorylation carrier, 7aa possesses therapeutic potentials in tackling angiogenesis related diseases.


2020 ◽  
Author(s):  
Xiaolin Wang ◽  
Yongqian Bian ◽  
Yuejun Li ◽  
Jing Li ◽  
Congying Zhao ◽  
...  

Abstract Background: DARC (The Duffy antigen receptor for chemokines) is a kind of glycosylated membrane protein that binds to members of the CXC chemokine family associated with angiogenesis and has recently been reported to be implicated in diverse normal physiologic processes. This study aimed to investigate the involvement of DARC in angiogenesis, which is known to generate new capillary blood vessels from preexisting ones. Methods: HDMECs (Human dermal microvascular endothelial cells) were divided into two groups (DARC overexpression group, and control group). We used Brdu staining to detect cell proliferation, and wound healing assay to detect cell migration. Then tube formation assay were observed. Also, western blot and immunofluorescent staining were used to estimate the relationship between DARC and RhoA (Ras homolog gene family, member A). Results: HDMECs proliferation, migration, and tube formation were inhibited significantly when DARC was overexpressed intracellular. DARC impaired microfilament dynamics and intercellular connection in migrating cells, and RhoA activation underlay the effect of DARC on endothelial cell. Furthermore, DARC inhibited the formation of new capillaries in vitro. Conclusion: Our findings revealed the role of DARC in the angiogenic process and provided a novel mechanism for RhoA activation during endothelial cell migration and angiogenesis.


2009 ◽  
Vol 30 (3) ◽  
pp. 545-554 ◽  
Author(s):  
Jiabin Guo ◽  
Diana N Krause ◽  
James Horne ◽  
John H Weiss ◽  
Xuejun Li ◽  
...  

Protective effects of estrogen against experimental stroke and neuronal ischemic insult are well-documented, but it is not known whether estrogen prevents ischemic injury to brain endothelium, a key component of the neurovascular unit. Increasing evidence indicates that estrogen exerts protective effects through mitochondrial mechanisms. We previously found 17β-estradiol (E2) to improve mitochondrial efficiency and reduce mitochondrial superoxide in brain blood vessels and endothelial cells. Thus we hypothesized E2 will preserve mitochondrial function and protect brain endothelial cells against ischemic damage. To test this, an in vitro ischemic model, oxygen-glucose deprivation (OGD)/reperfusion, was applied to immortalized mouse brain endothelial cells (bEnd.3). OGD/reperfusion-induced cell death was prevented by long-term (24, 48 h), but not short-term (0.5, 12 h), pretreatment with 10 nmol/L E2. Protective effects of E2 on endothelial cell viability were mimicked by an estrogen-receptor (ER) agonist selective for ERα (PPT), but not by one selective for ERβ (DPN). In addition, E2 significantly decreased mitochondrial superoxide and preserved mitochondrial membrane potential and ATP levels in early stages of OGD/reperfusion. All of the E2 effects were blocked by the ER antagonist, ICI-182,780. These findings indicate that E2 can preserve endothelial mitochondrial function and provide protection against ischemic injury through ER-mediated mechanisms.


Sign in / Sign up

Export Citation Format

Share Document