scholarly journals 0358: Differential AMP-activated protein kinase (AMPK) activation in platelets, in response to various agonists. Comparison between human and murine platelets

Author(s):  
Sophie Lepropre ◽  
Marie-Blanche Onselaer ◽  
Cécile Oury ◽  
Luc Bertrand ◽  
Jean-Louis Vanoverschelde ◽  
...  
2008 ◽  
Vol 294 (1) ◽  
pp. C126-C135 ◽  
Author(s):  
Dan Zheng ◽  
Anjana Perianayagam ◽  
Donna H. Lee ◽  
M. Douglas Brannan ◽  
Li E. Yang ◽  
...  

AMP-activated protein kinase (AMPK), activated by an increase in intracellular AMP-to-ATP ratio, stimulates pathways that can restore ATP levels. We tested the hypothesis that AMPK activation influences extracellular fluid (ECF) K+ homeostasis. In conscious rats, AMPK was activated with 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR) infusion: 38.4 mg/kg bolus then 4 mg·kg−1·min−1 infusion. Plasma [K+] and [glucose] both dropped at 1 h of AICAR infusion and [K+] dropped to 3.3 ± 0.04 mM by 3 h, linearly related to the increase in muscle AMPK phosphorylation. AICAR treatment did not increase urinary K+ excretion. AICAR lowered [K+] whether plasma [K+] was chronically elevated or lowered. The K+ infusion rate needed to maintain baseline plasma [K+] reached 15.7 ± 1.3 μmol K+·kg−1·min−1 between 120 and 180 min AICAR infusion. In mice expressing a dominant inhibitory form of AMPK in the muscle (Tg-KD1), baseline [K+] was not different from controls (4.2 ± 0.1 mM), but the fall in plasma [K+] in response to AICAR (0.25 g/kg) was blunted: [K+] fell to 3.6 ± 0.1 in controls and to 3.9 ± 0.1 mM in Tg-KD1, suggesting that ECF K+ redistributes, at least in part, to muscle ICF. In summary, these findings illustrate that activation of AMPK activity with AICAR provokes a significant fall in plasma [K+] and suggest a novel mechanism for redistributing K+ from ECF to ICF.


2019 ◽  
Vol 60 (5) ◽  
pp. 937-952 ◽  
Author(s):  
Anne-Emilie Declèves ◽  
Anna V. Mathew ◽  
Aaron M. Armando ◽  
Xianlin Han ◽  
Edward A. Dennis ◽  
...  

High-fat diet (HFD) causes renal lipotoxicity that is ameliorated with AMP-activated protein kinase (AMPK) activation. Although bioactive eicosanoids increase with HFD and are essential in regulation of renal disease, their role in the inflammatory response to HFD-induced kidney disease and their modulation by AMPK activation remain unexplored. In a mouse model, we explored the effects of HFD on eicosanoid synthesis and the role of AMPK activation in ameliorating these changes. We used targeted lipidomic profiling with quantitative MS to determine PUFA and eicosanoid content in kidneys, urine, and renal arterial and venous circulation. HFD increased phospholipase expression as well as the total and free pro-inflammatory arachidonic acid (AA) and anti-inflammatory DHA in kidneys. Consistent with the parent PUFA levels, the AA- and DHA-derived lipoxygenase (LOX), cytochrome P450, and nonenzymatic degradation (NE) metabolites increased in kidneys with HFD, while EPA-derived LOX and NE metabolites decreased. Conversely, treatment with 5-aminoimidazole-4-carboxamide-1-β-D-furanosyl 5′-monophosphate (AICAR), an AMPK activator, reduced the free AA and DHA content and the DHA-derived metabolites in kidney. Interestingly, kidney and circulating AA, AA metabolites, EPA-derived LOX, and NE metabolites are increased with HFD; whereas, DHA metabolites are increased in kidney in contrast to their decreased circulating levels with HFD. Together, these changes showcase HFD-induced pro- and anti-inflammatory eicosanoid dysregulation and highlight the role of AMPK in correcting HFD-induced dysregulated eicosanoid pathways.


2009 ◽  
Vol 116 (8) ◽  
pp. 607-620 ◽  
Author(s):  
Aaron K. F. Wong ◽  
Jacqueline Howie ◽  
John R. Petrie ◽  
Chim C. Lang

AMPK (AMP-activated protein kinase) is a heterotrimetric enzyme that is expressed in many tissues, including the heart and vasculature, and plays a central role in the regulation of energy homoeostasis. It is activated in response to stresses that lead to an increase in the cellular AMP/ATP ratio caused either by inhibition of ATP production (i.e. anoxia or ischaemia) or by accelerating ATP consumption (i.e. muscle contraction or fasting). In the heart, AMPK activity increases during ischaemia and functions to sustain ATP, cardiac function and myocardial viability. There is increasing evidence that AMPK is implicated in the pathophysiology of cardiovascular and metabolic diseases. A principle mode of AMPK activation is phosphorylation by upstream kinases [e.g. LKB1 and CaMK (Ca2+/calmodulin-dependent protein kinase], which leads to direct effects on tissues and phosphorylation of various downstream kinases [e.g. eEF2 (eukaryotic elongation factor 2) kinase and p70 S6 kinase]. These upstream and downstream kinases of AMPK have fundamental roles in glucose metabolism, fatty acid oxidation, protein synthesis and tumour suppression; consequently, they have been implicated in cardiac ischaemia, arrhythmias and hypertrophy. Recent mechanistic studies have shown that AMPK has an important role in the mechanism of action of MF (metformin), TDZs (thiazolinediones) and statins. Increased understanding of the beneficial effects of AMPK activation provides the rationale for targeting AMPK in the development of new therapeutic strategies for cardiometabolic disease.


2017 ◽  
Vol 8 (4) ◽  
pp. 1481-1493 ◽  
Author(s):  
Wenqi Yang ◽  
Xu Chen ◽  
Ming Chen ◽  
Yanping Li ◽  
Qing Li ◽  
...  

ER stress inhibition through AMPK activation may explain the protective effects of fish oil against HFD-induced insulin resistance.


2006 ◽  
Vol 203 (7) ◽  
pp. 1665-1670 ◽  
Author(s):  
Peter Tamás ◽  
Simon A. Hawley ◽  
Rosemary G. Clarke ◽  
Kirsty J. Mustard ◽  
Kevin Green ◽  
...  

The adenosine monophosphate (AMP)–activated protein kinase (AMPK) has a crucial role in maintaining cellular energy homeostasis. This study shows that human and mouse T lymphocytes express AMPKα1 and that this is rapidly activated in response to triggering of the T cell antigen receptor (TCR). TCR stimulation of AMPK was dependent on the adaptors LAT and SLP76 and could be mimicked by the elevation of intracellular Ca2+ with Ca2+ ionophores or thapsigargin. AMPK activation was also induced by energy stress and depletion of cellular adenosine triphosphate (ATP). However, TCR and Ca2+ stimulation of AMPK required the activity of Ca2+–calmodulin-dependent protein kinase kinases (CaMKKs), whereas AMPK activation induced by increased AMP/ATP ratios did not. These experiments reveal two distinct pathways for the regulation of AMPK in T lymphocytes. The role of AMPK is to promote ATP conservation and production. The rapid activation of AMPK in response to Ca2+ signaling in T lymphocytes thus reveals that TCR triggering is linked to an evolutionally conserved serine kinase that regulates energy metabolism. Moreover, AMPK does not just react to cellular energy depletion but also anticipates it.


2009 ◽  
Vol 30 (3) ◽  
pp. 480-492 ◽  
Author(s):  
Jun Li ◽  
Louise D McCullough

AMP-activated protein kinase (AMPK) is a serine threonine kinase that is highly conserved through evolution. AMPK is found in most mammalian tissues including the brain. As a key metabolic and stress sensor/effector, AMPK is activated under conditions of nutrient deprivation, vigorous exercise, or heat shock. However, it is becoming increasingly recognized that changes in AMPK activation not only signal unmet metabolic needs, but also are involved in sensing and responding to ‘cell stress’, including ischemia. The downstream effect of AMPK activation is dependent on many factors, including the severity of the stressor as well as the tissue examined. This review discusses recent in vitro and in vivo studies performed in the brain/neuronal cells and vasculature that have contributed to our understanding of AMPK in stroke. Recent data on the potential role of AMPK in angiogenesis and neurogenesis and the interaction of AMPK with 3-hydroxy-3-methy-glutaryl-CoA reductase inhibitors (statins) agents are highlighted. The interaction between AMPK and nitric oxide signaling is also discussed.


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