NADPH Oxidase<i>versus</i>Mitochondria-Derived ROS in Glucose-Induced Apoptosis of Pericytes in Early Diabetic Retinopathy

Mustapha, Nik Musaâ€TMadah; Tarr, Joanna M.; Kohner, Eva M.; Chibber, Rakesh

doi:10.1155/2010/746978

Cited by 54 publications

(47 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It was reported that Nox1, but not Nox2/gp91 phox , was predominantly expressed in pericytes isolated from the rat adipose-tissue microvasculature [28]. Previous studies suggested that ROS are produced via NADPH oxidase in retinal pericytes, which are thought to be analogous to brain pericytes, in response to some stimulants [29,30]. It was shown that Nox2 (gp91 phox ) was expressed and localized in the cytosol of bovine retinal pericytes; however, the expression of other Nox family members, including Nox4, in these cells was not investigated [30].…”

Section: Discussionmentioning

confidence: 99%

Nox4 Is a Major Source of Superoxide Production in Human Brain Pericytes

Kuroda¹,

Ago²,

Nishimura³

et al. 2014

J Vasc Res

View full text Add to dashboard Cite

Background: Pericytes are multifunctional cells surrounding capillaries and postcapillary venules. In brain microvasculature, pericytes play a pivotal role under physiological and pathological conditions by producing reactive oxygen species (ROS). The aims of this study were to elucidate the source of ROS and its regulation in human brain pericytes. Methods: The expression of Nox enzymes in the cells was evaluated using RT-PCR and western blot. Superoxide production was determined by superoxide dismutase-inhibitable chemiluminescence. Silencing of Nox4 was performed using RNAi, and cell proliferation was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. Results: Nox4 was predominant among the Nox family in human brain pericytes. Membrane fractions of cells produced superoxide in the presence of NAD(P)H. Superoxide production was almost abolished with diphenileneiodonium, a Nox inhibitor; however, inhibitors of other possible superoxide-producing enzymes had no effect on NAD(P)H-dependent superoxide production. Pericytes expressed angiotensin II (Ang II) receptors, and Ang II upregulated Nox4 expression. Hypoxic conditions also increased the Nox4 expression. Silencing of Nox4 significantly reduced ROS production and attenuated cell proliferation. Conclusion: Our study showed that Nox4 is a major superoxide-producing enzyme and that its expression is regulated by Ang II and hypoxic stress in human brain pericytes. In addition, Nox4 may promote cell growth.

show abstract

Section: Discussionmentioning

confidence: 99%

Nox4 Is a Major Source of Superoxide Production in Human Brain Pericytes

Kuroda¹,

Ago²,

Nishimura³

et al. 2014

J Vasc Res

View full text Add to dashboard Cite

show abstract

“…Results are expressed as mean fluorescence of CM-H 2 -DCFDA. NAD(P)H oxidase activity detection Glucose-induced NAD(P)H oxidase activity was measured in live HAEC exposed to the different treatment conditions for 30 min using lucigenin-derived chemiluminescence, as described by Mustapha et al [32]. For a more detailed description of methods, see the ESM.…”

Section: Methodsmentioning

confidence: 99%

C-peptide reduces high-glucose-induced apoptosis of endothelial cells and decreases NAD(P)H-oxidase reactive oxygen species generation in human aortic endothelial cells

et al. 2011

View full text Add to dashboard Cite

Aims/hypothesis Reactive oxygen species (ROS) generated during hyperglycaemia are implicated in the development of diabetic vascular complications. High glucose increases oxidative stress in endothelial cells and induces apoptosis. A major source of ROS in endothelial cells exposed to glucose is the NAD(P)H oxidase enzyme. Several studies demonstrated that C-peptide, the product of proinsulin cleavage within the pancreatic beta cells, displays anti-inflammatory effects in certain models of vascular dysfunction. However, the molecular mechanism underlying this effect is unclear. We hypothesised that C-peptide reduces glucose-induced ROS generation by decreasing NAD(P)H oxidase activation and prevents apoptosis Methods Human aortic endothelial cells (HAEC) were exposed to 25 mmol/l glucose in the presence or absence of C-peptide and tested for protein quantity and activity of caspase-3 and other apoptosis markers by ELISA, TUNEL and immunoblotting. Intracellular ROS were measured by flow cytometry using the ROS sensitive dye chloromethyl-2′,7′-dichlorodihydrofluorescein diacetate (CM-H 2 -DCDFA). NAD(P)H oxidase activation was assayed by lucigenin. Membrane and cytoplasmic levels of the NAD (P)H subunit ras-related C3 botulinum toxin substrate 1 (rho family, small GTP binding protein Rac1) (RAC-1) and its GTPase activity were studied by immunoblotting and ELISA. RAC-1 (also known as RAC1) gene expression was investigated by quantitative real-time PCR. Results C-peptide significantly decreased caspase-3 levels and activity and upregulated production of the antiapoptotic factor B cell CLL/lymphoma 2 (BCL-2). Glucose-induced ROS production was quenched by C-peptide and this was associated with a decreased NAD (P)H oxidase activity and reduced RAC-1 membrane production and GTPase activity. Conclusions/interpretation In glucose-exposed endothelial cells, C-peptide acts as an endogenous antioxidant molecule by reducing RAC-1 translocation to membrane and NAD (P)H oxidase activation. By preventing oxidative stress, C-peptide protects endothelial cells from glucose-induced apoptosis.

show abstract

“…DHE penetrates the cells and is oxidized by ROS to form ethidium, which binds to DNA to produce red nuclear fluorescence. 26 As assessed by an increase in nuclear DHE staining, incubation of HMDM with 25 mmol/L glucose for 8 or 24 hours increased intracellular ROS production ( Figure 1A). DHE fluorescence increased by 130.5Ϯ9.1% (PϽ0.01) after 8 hours of stimulation with 25 mmol/L glucose.…”

Section: Effect Of Lipid-free Apoa-i and Discoidal (A-i)rhdl On High-mentioning

confidence: 96%

Lipid-Free Apolipoprotein A-I and Discoidal Reconstituted High-Density Lipoproteins Differentially Inhibit Glucose-Induced Oxidative Stress in Human Macrophages

Tabet

Lambert

Torres

et al. 2011

ATVB

View full text Add to dashboard Cite

Objective-The goal of this study was to investigate the mechanisms by which apolipoprotein (apo) A-I, in the lipid-free form or as a constituent of discoidal reconstituted high-density lipoproteins ([A-I]rHDL), inhibits high-glucose-induced redox signaling in human monocyte-derived macrophages (HMDM). Methods and Results-HMDM were incubated under normal (5.8 mmol/L) or high-glucose (25 mmol/L) conditions with native high-density lipoproteins (HDL) lipid-free apoA-I from normal subjects and from subjects with type 2 diabetes (T2D) or (A-I)rHDL. Superoxide (O 2 Ϫ ) production was measured using dihydroethidium fluorescence. NADPH oxidase activity was assessed using lucigenin-derived chemiluminescence and a cyotochrome c assay. p47phox translocation to the plasma membrane, Nox2, superoxide dismutase 1 (SOD1), and SOD2 mRNA and protein levels were determined by real-time polymerase chain reaction and Western blotting. Native HDL induced a time-dependent inhibition of O 2 Ϫ generation in HMDM incubated with 25 mmol/L glucose. Lipid-free apoA-I and (A-I)rHDL increased SOD1 and SOD2 levels and attenuated 25 mmol/L glucose-mediated increases in cellular O 2 Ϫ , NADPH oxidase activity, p47 translocation, and Nox2 expression. Lipid-free apoA-I mediated its effects on Nox2, SOD1, and SOD2 via ABCA1. (A-I)rHDL-mediated effects were via ABCG1 and scavenger receptor BI. Lipid-free apoA-I from subjects with T2D inhibited reactive oxygen species generation less efficiently than normal apoA-I. Conclusion-Native

show abstract

NADPH OxidaseversusMitochondria-Derived ROS in Glucose-Induced Apoptosis of Pericytes in Early Diabetic Retinopathy

Cited by 54 publications

References 51 publications

Nox4 Is a Major Source of Superoxide Production in Human Brain Pericytes

Nox4 Is a Major Source of Superoxide Production in Human Brain Pericytes

C-peptide reduces high-glucose-induced apoptosis of endothelial cells and decreases NAD(P)H-oxidase reactive oxygen species generation in human aortic endothelial cells

Lipid-Free Apolipoprotein A-I and Discoidal Reconstituted High-Density Lipoproteins Differentially Inhibit Glucose-Induced Oxidative Stress in Human Macrophages

Contact Info

Product

Resources

About