scholarly journals Neuronal AMPK coordinates mitochondrial energy sensing and hypoxia resistance

2020 ◽  
Author(s):  
Brandon J. Berry ◽  
Aksana Baldzizhar ◽  
Andrew P. Wojtovich
Keyword(s):  
Protein Kinase ◽  
Mitochondrial Function ◽  
Stress Resistance ◽  
Atp Synthesis ◽  
Protonmotive Force ◽  
Electrochemical Gradient ◽  
Energy Sensing ◽  
Amp Activated Protein Kinase ◽  
Spatiotemporal Control

ABSTRACTOrganisms adapt to their environment through coordinated changes in mitochondrial function and metabolism. The mitochondrial protonmotive force (PMF) is an electrochemical gradient that powers ATP synthesis and adjusts metabolism to energetic demands via cellular signaling. It is unknown how or where transient PMF changes are sensed and signaled due to lack of precise spatiotemporal control in vivo. We addressed this by expressing a light-activated proton pump in mitochondria to spatiotemporally “turn off” mitochondrial function through PMF dissipation in tissues with light. We applied our construct – mitochondria-OFF (mtOFF) – to understand how metabolic status impacts hypoxia resistance, a response that relies on mitochondrial function. mtOFF activation induced starvation-like behavior mediated by AMP-activated protein kinase (AMPK). We found prophylactic mtOFF activation increased survival following hypoxia, and that protection relied on neuronal AMPK. Our study links spatiotemporal control of mitochondrial PMF to cellular metabolic changes that mediate behavior and stress resistance.

scholarly journals Chromatin-associated effectors of energy-sensing pathways mediate intergenerational effects

2020 ◽  
Author(s):  
Pedro Robles ◽  
Anisa Turner ◽  
Giusy Zuco ◽  
Panagiota Paganopolou ◽  
Beth Hill ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Protein Kinase ◽  
Sex Determination ◽  
Insulin Signaling ◽  
Stress Resistance ◽  
Nutrient Sensing ◽  
Intergenerational Effects ◽  
Mechanistic Target Of Rapamycin ◽  
Energy Sensing ◽  
Amp Activated Protein Kinase

Environmental stimuli experienced by the parental generation influence the phenotype of subsequent generations. The effects of these stimuli on the parental generation may be passed through the germline, but the mechanisms of this non-Mendelian type of inheritance are poorly known. Here we show that modulation of nutrient-sensing pathways in the parental generation of a nematode (Auanema freiburgensis) regulates phenotypic plasticity of its offspring. In response to pheromones, AMP-activated protein kinase (AMPK), mechanistic target of rapamycin complex 1 (mTORC1) and insulin signaling regulate stress resistance and sex determination across a generation. The effectors of these pathways are closely associated with the chromatin and their regulation affects the acetylation chromatin status in the germline. These results suggest that highly conserved metabolic sensors regulate phenotypic plasticity by changing the epigenetic status of the germline.

scholarly journals Controlling the Mitochondrial Protonmotive Force with Light to Impact Cellular Stress Resistance

2019 ◽  
Author(s):  
Brandon J. Berry ◽  
Adam J. Trewin ◽  
Alexander S. Milliken ◽  
Aksana Baldzizhar ◽  
Andrea M. Amitrano ◽  
...  
Keyword(s):  
Stress Resistance ◽  
Adaptive Response ◽  
Atp Synthesis ◽  
Proton Pumping ◽  
Protonmotive Force ◽  
Mitochondrial Inner Membrane ◽  
Reversible Method ◽  
Mitochondrial Toxins ◽  
Energy Sensing ◽  
Necessary And Sufficient

ABSTRACTMitochondrial respiration generates an electrochemical proton gradient across the mitochondrial inner membrane called the protonmotive force (PMF) to drive diverse functions and make ATP. Current techniques to manipulate the PMF are limited to its dissipation; there is no precise, reversible method to increase the PMF. To address this issue, we used an optogenetic approach and engineered a mitochondria-targeted light-activated proton pumping protein we called mitochondria-ON (mtON) to selectively increase the PMF. Here, mtON increased the PMF light dose-dependently, supported ATP synthesis, increased resistance to mitochondrial toxins, and modulated energy-sensing behavior in Caenorhabditis elegans. Moreover, transient mtON activation during hypoxia prevented the well-characterized adaptive response of hypoxic preconditioning. Our novel optogenetic approach demonstrated that a decreased PMF is both necessary and sufficient for hypoxia-stimulated stress resistance. Our results show that optogenetic manipulation of the PMF is a powerful tool to modulate metabolic and cell signaling outcomes.

scholarly journals Adrenaline is a critical mediator of acute exercise-induced AMP-activated protein kinase activation in adipocytes

2007 ◽  
Vol 403 (3) ◽  
pp. 473-481 ◽  
Author(s):  
Ho-Jin Koh ◽  
Michael F. Hirshman ◽  
Huamei He ◽  
Yangfeng Li ◽  
Yasuko Manabe ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase Activity ◽  
Chronic Exercise ◽  
Rat Adipocytes ◽  
Compound C ◽  
Isolated Adipocytes ◽  
Ampk Activity ◽  
Exercise Induced ◽  
Amp Activated Protein Kinase

Exercise increases AMPK (AMP-activated protein kinase) activity in human and rat adipocytes, but the underlying molecular mechanisms and functional consequences of this activation are not known. Since adrenaline (epinephrine) concentrations increase with exercise, in the present study we hypothesized that adrenaline activates AMPK in adipocytes. We show that a single bout of exercise increases AMPKα1 and α2 activities and ACC (acetyl-CoA carboxylase) Ser79 phosphorylation in rat adipocytes. Similarly to exercise, adrenaline treatment in vivo increased AMPK activities and ACC phosphorylation. Pre-treatment of rats with the β-blocker propranolol fully blocked exercise-induced AMPK activation. Increased AMPK activity with exercise and adrenaline treatment in vivo was accompanied by an increased AMP/ATP ratio. Adrenaline incubation of isolated adipocytes also increased the AMP/ATP ratio and AMPK activities, an effect blocked by propranolol. Adrenaline incubation increased lipolysis in isolated adipocytes, and Compound C, an AMPK inhibitor, attenuated this effect. Finally, a potential role for AMPK in the decreased adiposity associated with chronic exercise was suggested by marked increases in AMPKα1 and α2 activities in adipocytes from rats trained for 6 weeks. In conclusion, both acute and chronic exercise are significant regulators of AMPK activity in rat adipocytes. Our findings suggest that adrenaline plays a critical role in exercise-stimulated AMPKα1 and α2 activities in adipocytes, and that AMPK can function in the regulation of lipolysis.

scholarly journals Reactive Nitrogen Species Is Required for the Activation of the AMP-activated Protein Kinase by Statin in Vivo

2008 ◽  
Vol 283 (29) ◽  
pp. 20186-20197 ◽  
Author(s):  
Hyoung Chul Choi ◽  
Ping Song ◽  
Zhonglin Xie ◽  
Yong Wu ◽  
Jian Xu ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Reactive Nitrogen Species ◽  
Reactive Nitrogen ◽  
Nitrogen Species ◽  
Amp Activated Protein Kinase

scholarly journals Angiotensin AT1 receptor antagonism by losartan stimulates adipocyte browning via induction of apelin

2020 ◽  
Vol 295 (44) ◽  
pp. 14878-14892
Author(s):  
Dong Young Kim ◽  
Mi Jin Choi ◽  
Tae Kyung Ko ◽  
Na Hyun Lee ◽  
Ok-Hee Kim ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Protein Kinase ◽  
Metabolic Disorders ◽  
Angiotensin Ii Receptor ◽  
Adeno Associated Virus ◽  
Receptor Antagonism ◽  
White Adipocytes ◽  
Treatment Of Obesity ◽  
Amp Activated Protein Kinase

Adipocyte browning appears to be a potential therapeutic strategy to combat obesity and related metabolic disorders. Recent studies have shown that apelin, an adipokine, stimulates adipocyte browning and has negative cross-talk with angiotensin II receptor type 1 (AT1 receptor) signaling. Here, we report that losartan, a selective AT1 receptor antagonist, induces browning, as evidenced by an increase in browning marker expression, mitochondrial biogenesis, and oxygen consumption in murine adipocytes. In parallel, losartan up-regulated apelin expression, concomitant with increased phosphorylation of protein kinase B and AMP-activated protein kinase. However, the siRNA-mediated knockdown of apelin expression attenuated losartan-induced browning. Angiotensin II cotreatment also inhibited losartan-induced browning, suggesting that AT1 receptor antagonism-induced activation of apelin signaling may be responsible for adipocyte browning induced by losartan. The in vivo browning effects of losartan were confirmed using both C57BL/6J and ob/ob mice. Furthermore, in vivo apelin knockdown by adeno-associated virus carrying–apelin shRNA significantly inhibited losartan-induced adipocyte browning. In summary, these data suggested that AT1 receptor antagonism by losartan promotes the browning of white adipocytes via the induction of apelin expression. Therefore, apelin modulation may be an effective strategy for the treatment of obesity and its related metabolic disorders.

scholarly journals Withdrawal: Reactive nitrogen species is required for the activation of the AMP-activated protein kinase by statin in vivo.

2019 ◽  
Vol 294 (27) ◽  
pp. 10742-10742
Author(s):  
Hyoung Chul Choi ◽  
Ping Son ◽  
Zhonglin Xie ◽  
Yong Wu ◽  
Jian Xu ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Reactive Nitrogen Species ◽  
Reactive Nitrogen ◽  
Nitrogen Species ◽  
Amp Activated Protein Kinase

scholarly journals PRKAA1 Promotes Proliferation and Inhibits Apoptosis of Gastric Cancer Cells Through Activating JNK1 and Akt Pathways

2020 ◽  
Vol 28 (3) ◽  
pp. 213-223 ◽  
Author(s):  
Yangmei Zhang ◽  
Xichang Zhou ◽  
Long Cheng ◽  
Xiang Wang ◽  
Qinglin Zhang ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Protein Kinase ◽  
Cancer Cells ◽  
Akt Signaling ◽  
Catalytic Subunit ◽  
Gastric Cancer Cells ◽  
In Vivo Experiments ◽  
Compound C ◽  
Amp Activated Protein Kinase

PRKAA1 (protein kinase AMP-activated catalytic subunit α 1) is a catalytic subunit of AMP-activated protein kinase (AMPK), which plays a key role in regulating cellular energy metabolism through phosphorylation, and genetic variations in the PRKAA1 have been found to be associated with gastric cancer risk. However, the effect and underlying molecular mechanism of PRKAA1 on gastric cancer tumorigenesis, especially the proliferation and apoptosis, are not fully understood. Our data showed that PRKAA1 is highly expressed in BGC-823 and MKN45 cells and is expressed low in SGC-7901 and MGC-803 cells in comparison with the other gastric cancer cells. PRKAA1 downregulation by shRNA or treatment of AMPK inhibitor compound C significantly inhibited proliferation as well as promoted cell cycle arrest and apoptosis of BGC-823 and MKN45 cells. Moreover, the expression of PCNA and Bcl-2 and the activity of JNK1 and Akt signaling were also reduced in BGC-823 and MKN45 cells after PRKAA1 downregulation. In vivo experiments demonstrated that tumor growth in nude mice was significantly inhibited after PRKAA1 silencing. Importantly, inactivation of JNK1 or Akt signaling pathway significantly inhibited PRKAA1 overexpression-induced increased cell proliferation and decreased cell apoptosis in MGC-803 cells. In conclusion, our findings suggest that PRKAA1 increases proliferation and restrains apoptosis of gastric cancer cells through activating JNK1 and Akt pathways.

Sign in / Sign up

Export Citation Format

Share Document