scholarly journals Intracellular ATP levels in mouse cortical excitatory neurons varies with sleep–wake states

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Akiyo Natsubori ◽  
Tomomi Tsunematsu ◽  
Akihiro Karashima ◽  
Hiromi Imamura ◽  
Naoya Kabe ◽  
...  
Keyword(s):  
Negative Energy ◽  
Simultaneous Increase ◽  
Energy Status ◽  
Cellular Energy ◽  
Intracellular Atp ◽  
Energy Demands ◽  
Atp Levels ◽  
Excitatory Neurons ◽  
The Brain

AbstractWhilst the brain is assumed to exert homeostatic functions to keep the cellular energy status constant under physiological conditions, this has not been experimentally proven. Here, we conducted in vivo optical recordings of intracellular concentration of adenosine 5’-triphosphate (ATP), the major cellular energy metabolite, using a genetically encoded sensor in the mouse brain. We demonstrate that intracellular ATP levels in cortical excitatory neurons fluctuate in a cortex-wide manner depending on the sleep-wake states, correlating with arousal. Interestingly, ATP levels profoundly decreased during rapid eye movement sleep, suggesting a negative energy balance in neurons despite a simultaneous increase in cerebral hemodynamics for energy supply. The reduction in intracellular ATP was also observed in response to local electrical stimulation for neuronal activation, whereas the hemodynamics were simultaneously enhanced. These observations indicate that cerebral energy metabolism may not always meet neuronal energy demands, consequently resulting in physiological fluctuations of intracellular ATP levels in neurons.

scholarly journals LKB1 and AMPK maintain epithelial cell polarity under energetic stress

2007 ◽  
Vol 177 (3) ◽  
pp. 387-392 ◽  
Author(s):  
Vincent Mirouse ◽  
Lance L. Swick ◽  
Nevzat Kazgan ◽  
Daniel St Johnston ◽  
Jay E. Brenman
Keyword(s):  
Tumor Suppressor ◽  
Cell Polarity ◽  
Growth Control ◽  
Epithelial Polarity ◽  
Energy Status ◽  
Ampk Signaling ◽  
Cellular Energy ◽  
Energetic Stress ◽  
Stress Dependent

LKB1 is mutated in both familial and spontaneous tumors, and acts as a master kinase that activates the PAR-1 polarity kinase and the adenosine 5′monophosphate–activated kinase (AMPK). This has led to the hypothesis that LKB1 acts as a tumor suppressor because it is required to maintain cell polarity and growth control through PAR-1 and AMPK, respectively. However, the genetic analysis of LKB1–AMPK signaling in vertebrates has been complicated by the existence of multiple redundant AMPK subunits. We describe the identification of mutations in the single Drosophila melanogaster AMPK catalytic subunit AMPKα. Surprisingly, ampkα mutant epithelial cells lose their polarity and overproliferate under energetic stress. LKB1 is required in vivo for AMPK activation, and lkb1 mutations cause similar energetic stress–dependent phenotypes to ampkα mutations. Furthermore, lkb1 phenotypes are rescued by a phosphomimetic version of AMPKα. Thus, LKB1 signals through AMPK to coordinate epithelial polarity and proliferation with cellular energy status, and this might underlie the tumor suppressor function of LKB1.

Abstract 14459: The Cardioprotective Effect on Energy Metabolism of Empagliflozin in Heart of Type 2 Diabetes Model Mouse in vivo

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Masamichi Yamamoto ◽  
Yuichirou Kitai ◽  
Shigenori Yamamoto ◽  
Michael P Pieper ◽  
Yutaro Kotobuki ◽  
...  
Keyword(s):  
Heart Failure ◽  
Type 2 Diabetes ◽  
Placebo Group ◽  
Energy Metabolism ◽  
Treated Group ◽  
Atp Level ◽  
Intracellular Atp ◽  
Atp Levels

Chronic pathological conditions, such as type 2 diabetes mellitus, involve various mechanisms in promoting heart failure by remodelling energy metabolic pathways and impairing cardiac contractility. The major source of myocardial energetics has been reported to shifts from OXPHOS in normal conditions to glycolysis in heart failure. Therefore, we decided to focus on the effect of empagliflozin on energy metabolic status in the heart.Recently, we generated two types of transgenic mice to monitor energy metabolism, intracellular ATP levels (iATP Tg) and mitochondrial ATP levels (mATP Tg) using FRET biosensor “ATeam” in the whole body, organ, and cellular levels as well as in beating heart. We intercrossed these mice with db/db, a mouse model of type 2 diabetes, and examined the energy metabolism of the heart in the empagliflozin -treated or non-treated groups.db/db;iATP Tg mice were fed EMPA-containing diets (30 mg/kg b.w., day) from 7 weeks of age for 10 weeks, and the ATP levels in the heart were measured by imaging with a fluorescence microscope. The results showed that, unlike the lowered ATP levels in the placebo group, the intracellular ATP level in the heart was significantly increased in the empagliflozin-treated group. Also, the ATP level was recovered in this empagliflozin-treated group to the same level as the wild type.Next, 8 weeks-old db/db;mATP Tg mice received a single dose of empagliflozin (30 mg/kg b.w.) via oral gavage after 4 hr of fasting. After another 3 hr of fasting, monitor the mitochondrial ATP level of the heart in vivo under the fluorescent microscope. The results showed that, unlike the placebo group, the ATP level in the mitochondria of the heart was significantly increased in the empagliflozin-treated group.These results suggest that empagliflozin may restore normal remodelling of energy metabolism in type 2 diabetic hearts.

scholarly journals The Na+/K+ ATPase Regulates Glycolysis and Modifies Immune Metabolism in Tumors

2020 ◽  
Author(s):  
Sydney M. Sanderson ◽  
Zhengtao Xiao ◽  
Amy J. Wisdom ◽  
Shree Bose ◽  
Maria V. Liberti ◽  
...  
Keyword(s):  
Cardiac Tissue ◽  
Central Carbon Metabolism ◽  
Cancer Therapies ◽  
Cellular Energy ◽  
Energy Demands ◽  
Cell Type Specific ◽  
Cell Expression ◽  
Atpase Inhibition ◽  
Biomedical Interest

AbstractCancer therapies targeting metabolism have been limited due to a lack of understanding of the controlling properties of vulnerable pathways. The Na+/K+ ATPase is responsible for a large portion of cellular energy demands but how these demands influence metabolism and create metabolic liabilities are not known. Using metabolomic approaches, we first show that digoxin, a cardiac glycoside widely used in humans, acts through disruption to central carbon metabolism via on target inhibition of the Na+/K+ ATPase that was fully recovered by expression of an allele resistant to digoxin. We further show in vivo that administration of digoxin inhibits glycolysis in both malignant and healthy cells, particularly within clinically relevant cardiac tissue, while exhibiting tumor-specific cytotoxic activity in an allografted soft tissue sarcoma. Single-cell expression analysis of over 31,000 cells within the sarcoma shows that acute Na+/K+ ATPase inhibition shifts the immune composition of the tumor microenvironment, leading to selective alterations to metabolic programs in specific immune cells thus acting both through tumor cell and microenvironmental (e.g. macrophage) cells. These results provide evidence that altering energy demands can be used to regulate glycolysis with cell-type specific consequences in a multicellular environment of biomedical interest.

scholarly journals Effect of Perturbation of ATP Level on the Activity and Regulation of Nitrogenase in Rhodospirillum rubrum

2009 ◽  
Vol 191 (17) ◽  
pp. 5526-5537 ◽  
Author(s):  
Yaoping Zhang ◽  
Edward L. Pohlmann ◽  
Gary P. Roberts
Keyword(s):  
Rhodospirillum Rubrum ◽  
Nitrogenase Activity ◽  
Posttranslational Regulation ◽  
Modification System ◽  
Atp Level ◽  
In Vivo Test ◽  
Intracellular Atp ◽  
Atp Levels

ABSTRACT Nitrogenase activity in Rhodospirillum rubrum and in some other photosynthetic bacteria is regulated in part by the availability of light. This regulation is through a posttranslational modification system that is itself regulated by PII homologs in the cell. PII is one of the most broadly distributed regulatory proteins in nature and directly or indirectly senses nitrogen and carbon signals in the cell. However, its possible role in responding to light availability remains unclear. Because PII binds ATP, we tested the hypothesis that removal of light would affect PII by changing intracellular ATP levels, and this in turn would affect the regulation of nitrogenase activity. This in vivo test involved a variety of different methods for the measurement of ATP, as well as the deliberate perturbation of intracellular ATP levels by chemical and genetic means. To our surprise, we found fairly normal levels of nitrogenase activity and posttranslational regulation of nitrogenase even under conditions of drastically reduced ATP levels. This indicates that low ATP levels have no more than a modest impact on the PII-mediated regulation of NifA activity and on the posttranslational regulation of nitrogenase activity. The relatively high nitrogenase activity also shows that the ATP-dependent electron flux from dinitrogenase reductase to dinitrogenase is also surprisingly insensitive to a depleted ATP level. These in vivo results disprove the simple model of ATP as the key energy signal to PII under these conditions. We currently suppose that the ratio of ADP/ATP might be the relevant signal, as suggested by a number of recent in vitro analyses.

scholarly journals In Vivo Monitoring of Intracellular ATP Levels inLeishmania donovani Promastigotes as a Rapid Method To Screen Drugs Targeting Bioenergetic Metabolism

2001 ◽  
Vol 45 (4) ◽  
pp. 1121-1125 ◽  
Author(s):  
Juan Román Luque-Ortega ◽  
Octavio Miguel Rivero-Lezcano ◽  
Simon L. Croft ◽  
Luis Rivas
Keyword(s):  
Mitochondrial Membrane ◽  
Leishmania Donovani ◽  
Cell Number ◽  
Rapid Screening ◽  
Mitochondrial Activity ◽  
Intracellular Atp ◽  
Atp Levels ◽  
Bioenergetic Metabolism ◽  
Free Membrane

ABSTRACT A method for the rapid screening of drugs targeting the bioenergetic metabolism of Leishmania spp. was developed. The system is based on the monitoring of changes in the intracellular ATP levels of Leishmania donovani promastigotes that occur in vivo, as assessed by the luminescence produced by parasites transfected with a cytoplasmic form of Phothinus pyralisluciferase and incubated with free-membrane permeabled-luciferin analogued-luciferin–[1-(4,5-dimethoxy-2-nitrophenyl) ethyl ester]. A significant correlation was obtained between the rapid inhibition of luminescence with parasite proliferation and the dissipation of changes in mitochondrial membrane potential (ΔΨm) produced by buparvaquone or plumbagin, two leishmanicidal inhibitors of oxidative phosphorylation. To further validate this test, a screen of 14 standard leishmanicidal drugs, using a 50 μM cutoff, was carried out. Despite its semiquantitative properties and restriction to the promastigote stage, this test compares favorably with other bioenergetic parameters with respect to time and cell number requirements for the screening of drugs that affect mitochondrial activity.

scholarly journals Chromophorylation of cyanobacteriochrome Slr1393 from Synechocystis sp. PCC 6803 is regulated by protein Slr2111 through allosteric interaction

2018 ◽  
Vol 293 (46) ◽  
pp. 17705-17715 ◽  
Author(s):  
Qi He ◽  
Qi-Ying Tang ◽  
Ya-Fang Sun ◽  
Ming Zhou ◽  
Wolfgang Gärtner ◽  
...  
Keyword(s):  
Visible Spectrum ◽  
Molar Ratio ◽  
Domain Pair ◽  
Energy Status ◽  
Cellular Energy ◽  
Cbs Domain ◽  
Cbs Domains ◽  
Pcc 6803

Cyanobacteriochromes (CBCRs) are photochromic proteins in cyanobacteria that act as photosensors. CBCRs bind bilins as chromophores and sense nearly the entire visible spectrum of light, but the regulation of the chromophorylation of CBCRs is unknown. Slr1393 from Synechocystis sp. PCC 6803 is a CBCR containing three consecutive GAF (cGMP phosphodiesterase, adenylyl cyclase, and FhlA protein) domains, of which only the third one (Slr1393g3) can be phycocyanobilin-chromophorylated. The protein Slr2111 from Synechocystis sp. PCC 6803 includes a cystathionine β-synthase (CBS) domain pair of an as yet unknown function at its N terminus. CBS domains are often characterized as sensors of cellular energy status by binding nucleotides. In this work, we demonstrate that Slr2111 strongly interacts with Slr1393 in vivo and in vitro, which generates a complex in a 1:1 molar ratio. This tight interaction inhibits the chromophorylation of Slr1393g3, even if the chromophore is present. Instead, the complex stability and thereby the chromophorylation of Slr1393 are regulated by the binding of nucleotides (ATP, ADP, AMP) to the CBS domains of Slr2111 with varying affinities. It is demonstrated that residues Asp-53 and Arg-97 of Slr2111 are involved in nucleotide binding. While ATP binds to Slr2111, the association between the two proteins gets weaker and chromophorylation of Slr1393 are enabled. In contrast, AMP binding to Slr2111 leads to a stronger association, thereby inhibiting the chromophorylation. It is concluded that Slr2111 acts as a sensor of the cellular energy status that regulates the chromophorylation of Slr1393 and thereby its function as a light-driven histidine kinase.

Effect of pH and inhibitors on beta-amyloid fibril assembly

1996 ◽  
Vol 54 ◽  
pp. 752-753
Author(s):  
Beverly E. Maleeff ◽  
Timothy K. Hart ◽  
Stephen J. Wood ◽  
Ronald Wetzel
Keyword(s):  
Amyloid Fibril ◽  
Peptide Fragment ◽  
Hydrophobic Peptides ◽  
Amyloid Fibril Formation ◽  
Effects Of Ph ◽  
Severity Of The Disease ◽  
Kinetics Of ◽  
The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

Microvascular features that suggest effectors of blood-flow regulation in the brain: Evidence by SEM of corrosion casts of intracerebral vessels

1990 ◽  
Vol 48 (3) ◽  
pp. 274-275
Author(s):  
Enrico D.F. Motti ◽  
Hans-Georg Imhof ◽  
Gazi M. Yasargil
Keyword(s):  
Blood Flow ◽  
Perfusion Pressure ◽  
Corrosion Casts ◽  
Cerebral Microcirculation ◽  
Pial Arteries ◽  
Random Occurrence ◽  
Brain Arteries ◽  
Homogeneous Network ◽  
The Brain

Physiologists have devoted most attention in the cerebrovascular tree to the arterial side of the circulation which has been subdivided in three levels: 1) major brain arteries which keep microcirculation constant despite changes in perfusion pressure; 2) pial arteries supposed to be effectors regulating microcirculation; 3) intracerebral arteries supposed to be deprived of active cerebral blood flow regulating devices.The morphological search for microvascular effectors in the cerebrovascular bed has been elusive. The opaque substance of the brain confines in vivo investigation to the superficial pial arteries. Most morphologists had to limit their observation to the random occurrence of a favorable site in the practically two-dimensional thickness of diaphanized histological sections. It is then not surprising most investigators of the cerebral microcirculation refer to an homogeneous network of microvessels interposed between arterioles and venules.We have taken advantage of the excellent depth of focus afforded by the scanning electron microscope (SEM) to investigate corrosion casts obtained injecting a range of experimental animals with a modified Batson's acrylic mixture.

Automated System for Epileptic Seizures Prediction based on Multi-Channel Recordings of Electrical Brain Activity

2018 ◽  
pp. 115-122 ◽  
Author(s):  
V. A. Maksimenko ◽  
A. A. Harchenko ◽  
A. Lüttjohann
Keyword(s):  
Epileptic Seizure ◽  
Brain Activity ◽  
Epileptic Seizures ◽  
Automated System ◽  
Brain Computer Interfaces ◽  
Electrical Brain Activity ◽  
Computer Interfaces ◽  
Prediction And Prevention ◽  
The Brain

Introduction: Now the great interest in studying the brain activity based on detection of oscillatory patterns on the recorded data of electrical neuronal activity (electroencephalograms) is associated with the possibility of developing brain-computer interfaces. Braincomputer interfaces are based on the real-time detection of characteristic patterns on electroencephalograms and their transformation  into commands for controlling external devices. One of the important areas of the brain-computer interfaces application is the control of the pathological activity of the brain. This is in demand for epilepsy patients, who do not respond to drug treatment.Purpose: A technique for detecting the characteristic patterns of neural activity preceding the occurrence of epileptic seizures.Results:Using multi-channel electroencephalograms, we consider the dynamics of thalamo-cortical brain network, preceded the occurrence of an epileptic seizure. We have developed technique which allows to predict the occurrence of an epileptic seizure. The technique has been implemented in a brain-computer interface, which has been tested in-vivo on the animal model of absence epilepsy.Practical relevance:The results of our study demonstrate the possibility of epileptic seizures prediction based on multichannel electroencephalograms. The obtained results can be used in the development of neurointerfaces for the prediction and prevention of seizures of various types of epilepsy in humans. 

Sign in / Sign up

Export Citation Format

Share Document