A-769662 potentiates the effect of other AMP-activated protein kinase activators on cardiac glucose uptake

2014 ◽  
Vol 306 (12) ◽  
pp. H1619-H1630 ◽  
Author(s):  
Aurélie D. Timmermans ◽  
Magali Balteau ◽  
Roselle Gélinas ◽  
Edith Renguet ◽  
Audrey Ginion ◽  
...  

AMP-activated protein kinase (AMPK), a key cellular sensor of energy, regulates metabolic homeostasis and plays a protective role in the ischemic or diabetic heart. Stimulation of cardiac glucose uptake contributes to this AMPK-mediated protection. The small-molecule AMPK activator A-769662, which binds and directly activates AMPK, has recently been characterized. A-769662-dependent AMPK activation protects the heart against an ischemia-reperfusion episode but is unable to stimulate skeletal muscle glucose uptake. Here, we tried to reconcile these conflicting findings by investigating the impact of A-769662 on cardiac AMPK signaling and glucose uptake. We showed that A-769662 promoted AMPK activation, resulting in the phosphorylation of several downstream targets, but was incapable of stimulating glucose uptake in cultured cardiomyocytes and the perfused heart. The lack of glucose uptake stimulation can be explained by A-769662's narrow specificity, since it selectively activates cardiac AMPK heterotrimeric complexes containing α2/β1-subunits, the others being presumably required for this metabolic outcome. However, when combined with classical AMPK activators, such as metformin, phenformin, oligomycin, or hypoxia, which impact AMPK heterotrimers more broadly via elevation of cellular AMP levels, A-769662 induced more profound AMPK phosphorylation and subsequent glucose uptake stimulation. The synergistic effect of A-769662 under such ischemia-mimetic conditions protected cardiomyocytes against ROS production and cell death. In conclusion, despite the fact that A-769662 activates AMPK, it alone does not significantly stimulate glucose uptake. However, strikingly, its ability of potentiating the action on other AMPK activators makes it a potentially useful participant in the protective role of AMPK in the heart.

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Yina Ma ◽  
Wanqing Sun ◽  
Nanhu Quan ◽  
Lin Wang ◽  
Xingchi Chen ◽  
...  

Introduction: Ischemic heart disease is a leading cause of death, and it is caused by reduced blood flow to the ischemic area. Thus, an increasing nutrient uptake is a key approach to increase cardiomyocyte survival rate during the ischemia and reperfusion (I/R) period. TUG (tether containing a UBX domain, for GLUT4, 60 KDa) is a regulator of GLUT4 trafficking, it can be cleaved to mobilize GLUT4 from intracellular membranes to the cell surface after insulin stimulation in skeletal muscle. The energy sensor AMP-activated protein kinase (AMPK) is known to play an important cardioprotective role during myocardial I/R by regulating GLUT4 translocation and glucose uptake. Hypothesis: TUG is one of the downstream targets of AMPK, which can be phosphorylated by hypoxia/ischemia induced AMPK activation. Phosphorylation of TUG accelerates its cleavage and increases GLUT4 translocation during ischemia/reperfusion in the heart. Methods: In vitro hypoxia chamber and ex vivo isolated mouse heart perfusion Langendorff system were used to test the hypothesis. Antithrombin (AT) is an endogenous AMPK agonist in the heart, which was used to define the role of TUG in regulating GLUT4 trafficking during ischemia and reperfusion in the heart. Results: The ex vivo heart perfusion data demonstrated that AT triggered AMPK activation and significantly increase glucose uptake and GLUT4 translocation during ischemia and reperfusion (p<0.05 vs. vehicle). Intriguingly, GLUT4 immunoprecipitation data showed that AT treatment caused a dissociation of TUG from GLUT4. Moreover, AT treatment increased abundance of a TUG cleavage product (42 KDa) in response to I/R. All of these glucose transporter trafficking events are blunted in the AMPK kinase dead (KD) transgenic hearts. In HL-1 cardiomyocytes, TUG proteins were phosphorylated by activated AMPK during hypoxia. Moreover, TUG siRNA knockdown the TUG of HL-1 cells caused significantly increased cell surface GLUT4 and glucose uptake. Conclusions: Cardiac AMPK activation stimulates TUG cleavage and causes the dissociation between TUG and GLUT4 in the intracellular vesicles. TUG is a critical mediator that modulates cardiac GLUT4 translocation to cell surface and enhances glucose uptake by AMPK signaling pathway.


2017 ◽  
Vol 38 (2) ◽  
pp. 317-332 ◽  
Author(s):  
Victor Castro ◽  
Marta Skowronska ◽  
Jorge Lombardi ◽  
Jane He ◽  
Neil Seth ◽  
...  

Energetic regulation at the blood-brain barrier is critical for maintaining its integrity, transport capabilities, and brain demands for glucose. However, the underlying mechanisms that regulate these processes are still poorly explored. We recently characterized the protein occludin as a NADH oxidase and demonstrated its influence on the expression and activation of the histone deacetylase SIRT-1. Because SIRT-1 works in concert with AMP-activated protein kinase (AMPK) (AMPK), we investigated the impact of occludin on this metabolic switch. Here we show that in blood-brain barrier pericytes, occludin promotes AMPK expression and activation, influencing the expression of glucose transporters GLUT-1 and GLUT-4, glucose uptake, and ATP content. Furthermore, occludin expression, AMP-dependent protein kinase activity, and glucose uptake were altered under inflammatory (TNFα) and infectious (HIV) conditions. We also show that pericytes share glucose and mitochondria with astrocytes, and that occludin levels modify the ability of pericytes to share those energetic resources. In addition, we demonstrate that murine mitochondria can be transferred from live brain microvessels to energetically impaired human astrocytes, promoting their survival. Our findings demonstrate that occludin plays an important role in blood-brain barrier pericyte metabolism by influencing AMPK protein kinase activity, glucose uptake, ATP production, and by regulating the ability of pericytes to interact metabolically with astrocytes.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 526
Author(s):  
Sung Ho Lim ◽  
Jae Sik Yu ◽  
Ho Seon Lee ◽  
Chang-Ik Choi ◽  
Ki Hyun Kim

Morus alba (Moraceae), known as white mulberry, has been used to treat fever, protect against liver damage, improve eyesight, and lower blood sugar levels in traditional oriental medicine. Few studies have been conducted on the antidiabetic compounds identified from M. alba and their underlying mechanisms of action. Consequently, in this study, the fruits of M. alba were investigated for potential antidiabetic natural products using 3T3-L1 adipocytes. Phytochemical analysis of the ethanolic extract of M. alba fruits, followed by high-performance liquid chromatography (HPLC), purification led to the isolation of two main compounds: rutin and quercetin-3-O-β-d-glucoside (Q3G). Long-term use of available drugs for treating type 2 diabetes ((T2D) is often accompanied by undesirable side effects, which have generated increased interest in the development of more effective and safer antidiabetic agents. Examination of the isolated compounds, rutin and Q3G, for antidiabetic or anti-obesity properties or both in 3T3-L1 adipocytes demonstrated that they both improved glucose uptake via Akt-mediated insulin signaling pathway or AMP-activated protein kinase (AMPK) activation in 3T3-L1 adipocytes. The compounds also showed a positive effect on lipid accumulation in adipocytes, suggesting that glucose uptake occurred through activation of the Akt and AMPK signaling pathway without inducing adipogenesis. Taken together, our findings suggest that rutin and Q3G in M. alba fruits have the potential to induce fewer side effects such as weight gain, and these active compounds could be potential therapeutic candidates for the management of T2D.


2007 ◽  
Vol 292 (1) ◽  
pp. H326-H332 ◽  
Author(s):  
F. Spencer Gaskin ◽  
Kazuhiro Kamada ◽  
Mozow Yusof ◽  
Ronald J. Korthuis

Preconditioning (PC) with nitric oxide (NO) donors or agents that increase endothelial NO synthase (eNOS) activity 24 h before ischemia-reperfusion (I/R) prevents postischemic leukocyte rolling (LR) and stationary leukocyte adhesion (LA). Since 5′-AMP-activated protein kinase (AMPK) phosphorylates eNOS at Ser1177, resulting in activation, we postulated that AMPK activation may trigger the development of a preconditioned anti-inflammatory phenotype similar to that induced by NO donors. Wild-type (WT) C57BL/6J and eNOS−/− mice were treated with the AMPK agonist 5-aminoimidazole-4-carboxamide 1-β-d-furanoside (AICAR) 30 min (early AICAR PC) or 24 h (late AICAR PC) before I/R; LR and LA were quantified in single postcapillary venules in the jejunum using intravital microscopy. I/R induced comparable marked increases in LR and LA in WT and eNOS−/− mice relative to sham-operated (no ischemia) animals. Late AICAR PC prevented postischemic LR and LA, whereas early AICAR PC prevented LA in WT mice. Late AICAR PC was ineffective in preventing I/R-induced LR but not LA in the eNOS−/− mice, and the same pattern was seen in WT animals treated with the NOS inhibitor Nω-nitro-l-arginine. Early AICAR PC remained effective in preventing LA in eNOS−/− mice. Our results indicate that both early and late PC with an AMPK agonist produces an anti-inflammatory phenotype in postcapillary venules. Since the protection afforded by late AICAR PC on postischemic LR was prevented by NOS inhibition in WT mice and absent in eNOS-deficient mice, it appears that eNOS triggers this protective effect. In stark contrast, antecedent AMPK activation prevented I/R-induced LA by an eNOS-independent mechanism.


2020 ◽  
Vol 4 (01) ◽  
pp. E13-E18
Author(s):  
Kevin D. Brown ◽  
Edward D. Waggy ◽  
Sreejayan Nair ◽  
Timothy J. Robinson ◽  
Emily E. Schmitt ◽  
...  

AbstractIschemic heart disease presents with significant differences between sexes. Endurance exercise protects the heart against ischemic disease and also distinctly impacts male and female patients through unidentified mechanisms, though some evidence implicates 5′-AMP-activated protein kinase (AMPK). The purpose of this investigation was to assess the impact of training and sex on cardiac AMPK activation following exhaustive exercise. AMPK activation was measured in trained and sedentary mice of both sexes. Trained mice ran on a treadmill at progressively increasing speeds and duration for 12 weeks. Trained and sedentary mice of both sexes were euthanized immediately following exhaustive exercise and compared to sedentary controls. Endurance training elicited adaptations indicative of aerobic adaptation including higher max running velocities and cardiac hypertrophy with no differences between males and females. AMPK activity was higher in male compared to females, and trained exhibited higher AMPK activity compared to sedentary mice. In response to training, male mice activated AMPK more robustly than female mice. Chronic exercise training increases the ability to activate cardiac AMPK in response to exhaustive exercise in a sex-specific manner. Understanding the interaction between exercise and sex is vital for use of exercise as medicine for heart disease in both men and women.


2020 ◽  
Vol 17 (8) ◽  
pp. 735-752
Author(s):  
Peifeng Qiao ◽  
Jingxi Ma ◽  
Yangyang Wang ◽  
Zhenting Huang ◽  
Qian Zou ◽  
...  

Background: Neuroinflammation plays an important role in the pathophysiological process of various neurodegenerative diseases. It is well known that curcumin has obvious anti-inflammatory effects in various neuroinflammation models. However, its effect on the modulation of microglial polarization is largely unknown. Objective: This study aimed to investigate whether curcumin changed microglia to an anti-inflammatory M2-phenotype by activating the AMP-activated protein kinase (AMPK) signaling pathway. Methods: LPS treatment was used to establish BV2 cells and primary microglia neuroinflammation models. The neuroinflammation mouse model was established by an intracerebroventricular (ICV) injection of lipopolysaccharide (LPS) in the lateral septal complex region of the brain. TNF-α was measured by ELISA, and cell viability was measured by Cell Counting Kit-8 (CCK-8). The expression of proinflammatory and anti-inflammatory cytokines was examined by Q-PCR and Western blot analysis. Phenotypic polarization of BV2 microglia was detected by immunofluorescence. Results: Curcumin enhanced AMPK activation in BV2 microglial cells in the presence and absence of LPS. Upon LPS stimulation, the addition of curcumin promoted M2 polarization of BV2 cells, as evidenced by suppressed M1 and the elevated M2 signature protein and gene expression. The effects of curcumin were inhibited by an AMPK inhibitor or AMPK knockdown. Calmodulin-dependent protein kinase kinase β (CaMKKβ) and liver kinase B1 (LKB1) are upstream kinases that activate AMPK. Curcumin can activate AMPK in Hela cells, which do not express LKB1. However, both the CaMKKβ inhibitor and siRNA blocked curcumin activation of AMPK in LPS-stimulated BV2 cells. Moreover, the CaMKKβ inhibitor and siRNA weaken the effect of curcumin suppression on M1 and enhancement of M2 protein and gene expression in LPS-stimulated BV2 cells. Finally, curcumin enhanced AMPK activation in the brain area where microglia were over-activated upon LPS stimulation in an in vivo neuroinflammation model. Moreover, curcumin also suppressed M1 and promoted M2 signature protein and gene expression in this in vivo model. Conclusion: Curcumin enhances microglia M2 polarization via the CaMKKβ-dependent AMPK signaling pathway. Additionally, curcumin treatment was found to be neuroprotective and thus might be considered as a novel therapeutic agent to treat the neurodegenerative disease such as Alzheimer‘s disease, Parkinson's disease, etc.


Author(s):  
Sophie Lepropre ◽  
Marie-Blanche Onselaer ◽  
Cécile Oury ◽  
Luc Bertrand ◽  
Jean-Louis Vanoverschelde ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document