Inhibitor of G Protein-Coupled Receptor Kinase 2 Normalizes Vascular Endothelial Function in Type 2 Diabetic Mice by Improving β-Arrestin 2 Translocation and Ameliorating Akt/eNOS Signal Dysfunction

Taguchi, Kumiko; Matsumoto, Takayuki; Kamata, Katsuo; Kobayashi, Tsuneo

doi:10.1210/en.2012-1101

Cited by 30 publications

(48 citation statements)

References 45 publications

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“…Previously, we reported that the mechanism of clonidine-induced endotheliumdependent relaxation was via the Akt/eNOS signaling pathway and, in diabetes, the impaired clonidine-induced response was determined to be a cause of Akt/eNOS downregulation. [14][15][16]18) Briefly, in this study, we hypothesized that RV and clonidine may have a synergistic effect on Akt/eNOS activation. So, the experiment was designed to investigate the mechanism of vasorelaxation induced by clonidine under RV stimulation in the diabetic and control aortas.…”

Section: Effect Of Rv In Diabetic Micementioning

confidence: 99%

“…14,16,18) Measurement of Isometric Force Measurement of the isometric force was performed as described previously. 7,[14][15][16][17][18][20][21][22][23][24][25] Mice were anesthetized with 5% isoflurane and sacrificed by decapitation. The thoracic aortas were removed from mice and put in Krebs-Henseleit Solution (KHS) (consisted of KHS (mmol/L); 118.0 NaCl, 4.7 KCl, 25.0 NaHCO 3 , 1.8 CaCl 2 , 1.2 NaH 2 PO 4 , 1.2 MgSO 4 , and 11.0 glucose) and cut from perivascular fat carefully.…”

Section: Animals and Experimental Designmentioning

confidence: 99%

“…Measurement of NO Production NO production (nitrite and nitrate) was measured with the HPLC/Gries system (ENO-20, Eicom, Kyoto, Japan), as previously described. 15,23) The samples of aortic rings were cut into 5-mm segments and put in KHS (37°C). Some samples were treated with Aktinhibitor (10 −6 mol/L) for 30 min, and then, all samples were exposed to RV (10 −6 mol/L).…”

Section: Animals and Experimental Designmentioning

confidence: 99%

“…[14][15][16][17][18] So, we performed analysis of Akt phosphorylation at Ser473 and eNOS phosphorylation at Ser1177 during single stimulation with RV or clonidine in aortas from Control and DM mice (Fig. 5A).…”

Section: Effect Of Clonidine On Phosphorylation Levels Of Akt and Enomentioning

confidence: 99%

“…13) Evidence from our previous experimental data indicates that clonidine promotes the Akt/eNOS pathway, but it inhibits the pathway in the diabetic aorta. [14][15][16][17][18] Furthermore, Xia et al showed that RV increased Akt phosphorylation in endothelial progenitor cells. 19) Given the importance of vasoprotective NO bioavailability in endothelial cells, the aim of this study was to determine the role of eNOS activity in RV-induced relaxation in aortic rings from control and diabetic mice.…”

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Resveratrol Ameliorates Clonidine-Induced Endothelium-Dependent Relaxation Involving Akt and Endothelial Nitric Oxide Synthase Regulation in Type 2 Diabetic Mice

Taguchi

Hida

Matsumoto

et al. 2015

Biological & Pharmaceutical Bulletin

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Diabetic vascular complication is one of the manifestations of endothelial dysfunction. Resveratrol (RV)is considered to be beneficial in protecting endothelial function. However, the exact protective effect and mechanisms involved have not been fully clarified. In this study, we investigated the relationship between Akt/endothelial nitric oxide synthase (eNOS) activation and RV in diabetes-induced endothelial dysfunction. Aortas were dissected and placed in organ chambers, and nitric oxide (NO) production in response to acetylcholine (ACh) and RV was measured. ACh-induced endothelium-dependent relaxation was markedly increased in controls by RV pretreatment. Furthermore, RV caused NO-dependent relaxation via the Akt signaling pathway, which was weaker in the aortas of diabetic mice than age-matched controls. To further examine the underlying mechanisms, we measured the phosphorylation of Akt and eNOS by Western blotting. RV caused the phosphorylation of Akt and eNOS in aortas, which was decreased in diabetic mice. However, RV augmented the impaired clonidine-induced relaxation in diabetic mice. Interestingly, the phosphorylation of Akt and eNOS was increased under stimulation with RV and clonidine only in diabetic mice. Thus, either RV or clonidine causes Akt-dependent NO-mediated relaxation, which is weaker in diabetic mice than controls. However, additional exposure to RV and clonidine has an augmenting effect on the Akt/eNOS signaling pathway under diabetic conditions. RV-induced Akt/eNOS activity may be a common link involved in the clonidine-induced Akt/eNOS activity, so RV and clonidine may have a synergistic effect. Key words resveratrol (RV); endothelial dysfunction; nitric oxide (NO); AktType 2 diabetes (DM) is associated with several complications, especially vascular complications (e.g., coronary insufficiency, cerebrovascular and peripheral vascular disease), which are the main etiologies leading to morbidity and mortality.1) Patients with DM exhibit complex vascular changes, such as an accelerated atherosclerosis process and hypercoagulability.2) Atherosclerosis is a major factor that accelerates diabetic vascular complications, and vascular endothelial dysfunction is considered to be the earliest detectable abnormality in the process of atherosclerosis.3) Thus, improving vascular endothelial dysfunction plays an important role in diabetic treatment.Resveratrol (RV; 3,5,4′-trihydroxystilbene) is a naturally occurring polyphenolic phytoalexin found in many plants, and it has been shown to prolong the lifespan of lower organisms. 4)Foods and drinks rich in RV, such as Mediterranean diets and French wine, are associated with a reduced risk of cardiovascular mortality in humans, and evidence has confirmed that RV has antiapoptotic, anti-inflammatory, anti-aging, and anticancer effects as well as a cardiovascular protective effect. 5-7)We previously reported that RV increased nitric oxide (NO) production in diabetic mice. 8) However, the underlying mechanisms are complicated and remain unclear.Endotheli...

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Section: Effect Of Rv In Diabetic Micementioning

confidence: 99%

Section: Animals and Experimental Designmentioning

confidence: 99%

Section: Animals and Experimental Designmentioning

confidence: 99%

Section: Effect Of Clonidine On Phosphorylation Levels Of Akt and Enomentioning

confidence: 99%

mentioning

confidence: 99%

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Resveratrol Ameliorates Clonidine-Induced Endothelium-Dependent Relaxation Involving Akt and Endothelial Nitric Oxide Synthase Regulation in Type 2 Diabetic Mice

Taguchi

Hida

Matsumoto

et al. 2015

Biological & Pharmaceutical Bulletin

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Phosphorylation of Akt at Thr308 regulates p‐eNOS Ser1177 during physiological conditions

et al. 2021

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Endothelial nitric oxide synthase (eNOS)-derived nitric oxide (NO) plays a crucial role in maintaining vascular homeostasis. As a hallmark of eNOS activation, phosphorylation of eNOS at Ser1177 induced by activated protein kinase B (PKB/Akt) is pivotal for NO production. The complete activation of Akt requires its phosphorylation of both Thr308 and Ser473. However, which site plays the main role in regulating phosphorylation of eNOS Ser1177 is still controversial. The purpose of the present study is to explore the specific regulatory mechanism of phosphorylated Akt in eNOS activation. Inhibition of Akt Thr308 phosphorylation by a specific inhibitor or by siRNA in vitro, led to a decrease in eNOS phosphorylation at Ser1177 and to lower NO concentration in the cell culture medium of HUVECs. Whereas, inhibiting p-Akt Ser473 had no effect on eNOS phosphorylation at Ser1177.Next, we administered mice with inhibitors to downregulate p-Akt Ser473 or Thr308 activity. Along with the inhibition of p-Akt Thr308, vascular p-eNOS Ser1177 protein was simultaneously downregulated in parallel with a decrease in plasma NO concentration. Additionally, we cultured HUVECs at various temperature conditions (37°C, 22°C, and 4°C). The results showed that p-Akt Ser473 was gradually decreased in line with the reduction in temperature, accompanied with increased levels of p-Akt Thr308 and p-eNOS Ser1177. Taken together, our study indicates that the phosphorylation of Akt at Thr308, but not at Ser473, plays a more significant role in regulating p-eNOS Ser1177 levels under physiological conditions.

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Dietary polyphenol morin rescues endothelial dysfunction in a diabetic mouse model by activating the Akt/eNOS pathway

Taguchi

Hida

Hasegawa

et al. 2015

Molecular Nutrition Food Res

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Inhibitor of G Protein-Coupled Receptor Kinase 2 Normalizes Vascular Endothelial Function in Type 2 Diabetic Mice by Improving β-Arrestin 2 Translocation and Ameliorating Akt/eNOS Signal Dysfunction

Cited by 30 publications

References 45 publications

Resveratrol Ameliorates Clonidine-Induced Endothelium-Dependent Relaxation Involving Akt and Endothelial Nitric Oxide Synthase Regulation in Type 2 Diabetic Mice

Resveratrol Ameliorates Clonidine-Induced Endothelium-Dependent Relaxation Involving Akt and Endothelial Nitric Oxide Synthase Regulation in Type 2 Diabetic Mice

Phosphorylation of Akt at Thr308 regulates p‐eNOS Ser1177 during physiological conditions

Dietary polyphenol morin rescues endothelial dysfunction in a diabetic mouse model by activating the Akt/eNOS pathway

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