scholarly journals Endothelium-Selective Activation of AMP-Activated Protein Kinase Prevents Diabetes Mellitus–Induced Impairment in Vascular Function and Reendothelialization via Induction of Heme Oxygenase-1 in Mice

Circulation ◽  
2012 ◽  
Vol 126 (10) ◽  
pp. 1267-1277 ◽  
Author(s):  
Francois Y.L. Li ◽  
Karen S.L. Lam ◽  
Hung-Fat Tse ◽  
Cheng Chen ◽  
Yiqun Wang ◽  
...  
2015 ◽  
Vol 308 (3) ◽  
pp. F226-F236 ◽  
Author(s):  
Hyosang Kim ◽  
Soo Young Moon ◽  
Joon-Seok Kim ◽  
Chung Hee Baek ◽  
Miyeon Kim ◽  
...  

It has been suggested that endoplasmic reticulum (ER) stress facilitates fibrotic remodeling. Therefore, modulation of ER stress may serve as one of the possible therapeutic approaches to renal fibrosis. We examined whether and how activation of AMP-activated protein kinase (AMPK) suppressed ER stress induced by chemical ER stress inducers [tunicamycin (TM) and thapsigargin (TG)] and also nonchemical inducers in tubular HK-2 cells. We further investigated the in vivo effects of AMPK on ER stress and renal fibrosis. Western blot analysis, immunofluorescence, small interfering (si)RNA experiments, and immunohistochemical staining were performed. Metformin (the best known clinical activator of AMPK) suppressed TM- or TG-induced ER stress, as shown by the inhibition of TM- or TG-induced upregulation of glucose-related protein (GRP)78 and phosphorylated eukaryotic initiation factor-2α through induction of heme oxygenase-1. Metformin inhibited TM- or TG-induced epithelial-mesenchymal transitions as well. Compound C (AMPK inhibitor) blocked the effect of metformin, and 5-aminoimidazole-4-carboxamide-1β riboside (another AMPK activator) exerted the same effects as metformin. Transfection with siRNA targeting AMPK blocked the effect of metformin. Consistent with the results of cell culture experiments, metformin reduced renal cortical GRP78 expression and increased heme oxygenase-1 expression in a mouse model of ER stress-induced acute kidney injury by TM. Activation of AMPK also suppressed ER stress by transforming growth factor-β, ANG II, aldosterone, and high glucose. Furthermore, metformin reduced GRP78 expression and renal fibrosis in a mouse model of unilateral ureteral obstruction. In conclusion, AMPK may serve as a promising therapeutic target through reducing ER stress and renal fibrosis.


2021 ◽  
Vol 12 ◽  
Author(s):  
Huiya Huang ◽  
Linlin Wang ◽  
Fanyu Qian ◽  
Xiong Chen ◽  
Haiping Zhu ◽  
...  

Background/Aims: Diabetic foot ulcers (DFUs) present a major challenge in clinical practice, and hyperglycemia-induced angiogenesis disturbance and endothelial dysfunction likely exacerbate DFUs. The long-acting glucagon-like peptide-1 (GLP-1) analog liraglutide (Lira) is a potential activator of AMP-activated protein kinase (AMPK) that appears to enhance endothelial function and have substantial pro-angiogenesis and antioxidant stress effects. Therefore, in this study, we aimed to investigate whether the protective role of Lira in diabetic wound healing acts against the mechanisms underlying hyperglycemia-induced endothelial dysfunction and angiogenesis disturbance.Methods: Accordingly, db/db mice were assessed after receiving subcutaneous Lira injections. We also cultured human umbilical vein endothelial cells (HUVECs) in either normal or high glucose (5.5 or 33 mM glucose, respectively) medium with or without Lira for 72 h.Results: An obvious inhibition of hyperglycemia-triggered endothelial dysfunction and angiogenesis disturbance was observed; follow by a promotion of diabetic wound healing under Lira treatment combined with restored hyperglycemia-impaired AMPK signaling pathway activity. AMPKα1/2 siRNA and Compound C (Cpd C), an inhibitor of AMPK, abolished both Lira-mediated endothelial protection and pro-angiogenesis action, as well as the diabetic wound healing promoted by Lira. Furthermore, hypoxia inducible factor-1α (Hif-1α; transcription factors of AMPK substrates) knockdown in HUVECs and db/db mice demonstrated that Lira activated AMPK to prevent hyperglycemia-triggered endothelial dysfunction and angiogenesis disturbance, with a subsequent promotion of diabetic wound healing that was Hif-1α–heme oxygenase-1 (HO-1) axis-dependent. Taken together, these findings reveal that the promotion of diabetic wound healing by Lira occurs via its AMPK-dependent endothelial protection and pro-angiogenic effects, which are regulated by the Hif-1α–HO-1 axis.


2017 ◽  
Vol 95 (12) ◽  
pp. 1406-1413 ◽  
Author(s):  
Esra Aycan-Ustyol ◽  
Merve Kabasakal ◽  
Seldag Bekpinar ◽  
F. Ilkay Alp-Yıldırım ◽  
Ozge Tepe ◽  
...  

Increased oxidative stress and disturbance in nitric oxide bioavailability lead to endothelial dysfunction and cardiovascular complication in renal disease. Gentamicin (GM), a commonly used antibiotic, exhibits a toxic effect on renal proximal tubules. Prevention of its nephrotoxicity is important. Therefore, we investigated whether heme oxygenase 1 HO-1) induction influenced kidney and vascular function in GM-administered rats. GM (100 mg·kg–1·day–1; i.p.) was given to rats alone or together with hemin (20 mg·kg–1 on alternate days; i.p.) for 14 days. Plasma and kidney l-arginine, asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA) as well as kidney 4-hydroxynonenal (HNE) levels and myeloperoxidase (MPO) activity were measured. Histopathological examinations of kidney and relaxation and contraction responses of aorta were also examined. GM increased serum SDMA, urea nitrogen (BUN), and creatinine levels and caused histopathological alterations in the kidney. GM elevated HO-1 protein and mRNA expressions, 4-HNE level, and MPO activity and decreased antioxidant enzyme activities and l-arginine levels in the kidney. Decreased relaxation and contraction were detected in the aorta. Hemin restored renal oxidative stress and inflammatory changes together with vascular dysfunction, but did not affect SDMA, BUN, or creatinine levels. We conclude that HO-1 induction may be effective in improving renal oxidative stress, inflammation, and vascular dysfunction mediated by GM.


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