NADPH Oxidase 4 Mediates Insulin-Stimulated HIF-1α and VEGF Expression, and Angiogenesis In Vitro

Meng, Dan; Mei, Aihong; Liu, Junxu; Kang, Xueling; Shi, Xianglin; Ran, Qian; Chen, SF

doi:10.1371/journal.pone.0048393

Cited by 72 publications

(64 citation statements)

References 39 publications

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“…In turn, this insulin resistance can cause endothelial damage and impair the formation of NO. 26 Although our results were obtained from isolated retinal vessels incubated in high glucose media and not from vessels of diabetic animals, the high glucose media clearly suppressed the insulin-induced NO formation. Moreover, insulin reversibly decreased NO formation in endothelial cells cultured under high glucose conditions.…”

Section: Discussionmentioning

confidence: 54%

“…Nicotinamide adenine dinucleotide phosphate oxidase is a primary source of superoxide anions in retinal microvessels, 12 which are also the target of insulin. 26 Thus, these findings suggest that high glucose conditions cause oxidative stress, while insulin enhances the formation of superoxide through the uncoupling of NOS and NADPH oxidase.…”

Section: Insulin-induced Nitric Oxide In Retinal Microvesselsmentioning

confidence: 89%

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NADPH Oxidase–Mediated ROS Production Determines Insulin's Action on the Retinal Microvasculature

Oku

Horie

Matsuo

et al. 2015

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. To determine whether insulin induces nitric oxide (NO) formation in retinal microvessels and to examine the effects of high glucose on the formation of NO. METHODS.Freshly isolated rat retinal microvessels were incubated in normal (5.5 mM) or high (20 mM) glucose with or without insulin (100 nM). The levels of insulin-induced NO and reactive oxygen species (ROS) in the retinal microvessels were determined semiquantitatively using fluorescent probes, 4,5-diaminofluorescein diacetate, and hydroethidine, respectively, and a laser scanning confocal microscope. The insulin-induced changes of NO in rat retinal endothelial cells and pericytes cultured at different glucose concentrations (5.5 and 25 mM) were determined using flow cytometry. Nitric oxide synthase (NOS) protein levels were determined by Western blot analysis; intracellular levels of ROS were determined using fluorescence-activated cell sorting (FACS) analysis of ethidium fluorescence; and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase RNA expression was quantified using realtime PCR.RESULTS. Exposure of microvessels to insulin under normal glucose conditions led to a significant increase in NO levels; however, this increase was significantly suppressed when the microvessels were incubated under high glucose conditions. Intracellular levels of ROS were significantly increased in both retinal microvessels and cultured microvascular cells under high glucose conditions. The expression of NOS and NADPH oxidase were significantly increased in endothelial cells and pericytes under high glucose conditions. CONCLUSIONS. The increased formation of NO by insulin and its suppression by high glucose conditions suggests that ROS production mediated by NADPH oxidase is important by insulin's effect on the retinal microvasculature.Keywords: insulin, nitric oxide, ROS, high glucose, retinal microvessel N itric oxide (NO) is an endothelium-derived vasodilator, which plays a role in the autoregulation of ocular circulation. 1 Insulin stimulates the formation of NO and increases ocular blood flow. 2,3 Both insulin and NO are involved in the pathogenesis of diabetic retinopathy. Insulin treatment is related to the severity of diabetic retinopathy, [4][5][6] and care must be taken because insulin therapy often causes a temporary worsening of the diabetic retinopathy. Because increased levels of NO are associated with the breakdown of the blood-retinal barrier 7 and formation of diabetic macular edema, 8 the detrimental effects associated with the use of insulin in patients with diabetic retinopathy may be the result of changes in the bioavailability of insulin-induced NO.Hyperglycemia is the primary cause of macro-and microvascular complications in individuals with diabetes, but this is still a debated topic.9-11 Reactive oxygen species (ROS), including superoxides (O 2 À ), are produced endogenously by endothelial cells in response to cytokines, growth factors, and/ or shear stress. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is the prima...

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Section: Discussionmentioning

confidence: 54%

Section: Insulin-induced Nitric Oxide In Retinal Microvesselsmentioning

confidence: 89%

NADPH Oxidase–Mediated ROS Production Determines Insulin's Action on the Retinal Microvasculature

Oku

Horie

Matsuo

et al. 2015

Invest. Ophthalmol. Vis. Sci.

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“…Admittedly, insulin therapy is linked to DR, DME and potentially to DR severity, but the precise mechanistic link is questionable as yet. Current insights uniquely provided by in vitro studies point out vascular endothelial growth factor (VEGF) signalling in retinal microvascular endothelial cells as the hallmark in the pathophysiology of insulin-associated DR (11,20). Indeed, an in vitro study by Meng et al (20) demonstrated that insulin interacts with the NADPH oxidase subunit 4 (Nox-4) to induce excess production of reactive oxygen species (ROS) and subsequently oxidative stress in the retinal endothelial cells.…”

Section: Discussionmentioning

confidence: 99%

“…ROS produced by insulin are involved in hypoxia-inducible factor-1α (HIF-1α) activation which in turn leads to the expression of VEGF. The latter molecule mediates angiogenesis, neovascularization, and blood-retinal barrier disruption allowing vascular leakage as well (11,20). Taken together, the onset and worsening of DR and DME attributed to insulin use might result from ROS signalling via activation of HIF-1α and consequential VEGF expression.…”

Section: Discussionmentioning

confidence: 99%

Association of insulin treatment versus oral hypoglycaemic agents with diabetic retinopathy and its severity in type 2 diabetes patients in Cameroon, sub-Saharan Africa

Jingi¹,

Noubiap²,

Essouma³

et al. 2016

Ann. Transl. Med.

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Background: Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease associated with multiple macro and microvascular complications, diabetic retinopathy (DR) being the commonest one. Recent literature has reported an increased risk of DR with insulin use. Methods:We carried out a cross-sectional study at the Ophthalmology Department of the Douala General Hospital (DGH) during a 2-year period to explore the association between insulin treatment and both DR and its severity as compared with oral hypoglycemic agents (OHAs) in Cameroonian T2DM patients aged ≥35 years, and who were all screened for DR through eye examination including exhaustive retinal evaluation.Results: In total, medical files of 134 T2DM patients were analyzed. The frequency of DR was 54.1% among patients on OHA and 73.9% among those on insulin treatment, giving an overall frequency of 57.5%. There were significantly more OHA treated patients than insulin treated patients (82.8% vs. 17.2%, P<0.001). As expected, both the OHA and insulin groups were comparable by age, sex, duration of diabetes, past history of hypertension, alcohol misuse, and current tobacco smoking. DR was almost significantly more frequent in T2DM patients under insulin regimen than in patients under OHA [73.9% vs. 54.1%; odds ratio (OR) 2.4; 95% confidence interval (CI), 0.9-6.6; P=0.06]. Proliferative diabetic retinopathy (PDR) was significantly more observed in insulin treated patients than in OHA treated patients (34.8% vs. 15.3%; OR 2.95; 95% CI, 1.1-8; P=0.035). Irrespective of staging, the frequency of diabetic macular edema (DME) was significantly higher in the insulin group than in the OHA group (43.5% vs.19.8%; OR 3.1; 95% CI, 1.2-8; P=0.019).Conclusions: Compared with OHA, insulin therapy may be associated with DR, DR severity and DME in these T2DM sub-Saharan African patients.

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“…It may be that the RTKs couple to the same oxidase to induce signalling through protein oxidation. This is supported by evidence of insulin-induced angiogenesis through a Nox4-dependent mechanism 28,29 .…”

Section: Resultsmentioning

confidence: 71%

Deficient angiogenesis in redox-dead Cys17Ser PKARIα knock-in mice

et al. 2015

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Angiogenesis is essential for tissue development, wound healing and tissue perfusion, with its dysregulation linked to tumorigenesis, rheumatoid arthritis and heart disease. Here we show that pro-angiogenic stimuli couple to NADPH oxidase-dependent generation of oxidants that catalyse an activating intermolecular-disulphide between regulatory-RIa subunits of protein kinase A (PKA), which stimulates PKA-dependent ERK signalling. This is crucial to blood vessel growth as 'redox-dead' Cys17Ser RIa knock-in mice fully resistant to PKA disulphide-activation have deficient angiogenesis in models of hind limb ischaemia and tumour-implant growth. Disulphide-activation of PKA represents a new therapeutic target in diseases with aberrant angiogenesis.

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NADPH Oxidase 4 Mediates Insulin-Stimulated HIF-1α and VEGF Expression, and Angiogenesis In Vitro

Cited by 72 publications

References 39 publications

NADPH Oxidase–Mediated ROS Production Determines Insulin's Action on the Retinal Microvasculature

NADPH Oxidase–Mediated ROS Production Determines Insulin's Action on the Retinal Microvasculature

Association of insulin treatment versus oral hypoglycaemic agents with diabetic retinopathy and its severity in type 2 diabetes patients in Cameroon, sub-Saharan Africa

Deficient angiogenesis in redox-dead Cys17Ser PKARIα knock-in mice

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