scholarly journals Biochemical Regulation of the Glyoxalase System in Response to Insulin Signaling

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 326
Author(s):  
Der-Yen Lee ◽  
Yu-Chin Lin ◽  
Geen-Dong Chang
Keyword(s):  
Insulin Signaling ◽  
Redox State ◽  
Enzyme System ◽  
Insulin Stimulation ◽  
Glyoxalase System ◽  
Cellular Redox ◽  
Rate Determining Step ◽  
Biochemical Regulation ◽  
Glyoxalase 2 ◽  
In Cells

Methylglyoxal (MG) is a reactive glycation metabolite and potentially induces dicarbonyl stress. The production of MG in cells is increased along with an increase in carbohydrate metabolism. The efficiency of the glyoxalase system, consisting of glyoxalase 1 (GlxI) and glyoxalase 2 (GlxII), is crucial for turning the accumulated MG into nontoxic metabolites. Converting MG-glutathione hemithioacetal to S-d-lactoylglutathione by GlxI is the rate-determining step of the enzyme system. In this study, we found lactic acid accumulated during insulin stimulation in cells, however, cellular MG and S-d-lactoylglutathione also increased due to the massive flux of glycolytic intermediates. The insulin-induced accumulation of MG and S-d-lactoylglutathione were efficiently removed by the treatment of metformin, possibly via affecting the glyoxalase system. With the application of isotopic 13C3-MG, the flux of MG from extracellular and intracellular origins was dissected. While insulin induced an influx of extracellular MG, metformin inhibited the trafficking of MG across the plasma membrane. Therefore, metformin could maintain the extracellular MG by means of reducing the secretion of MG rather than facilitating the scavenging. In addition, metformin may affect the glyoxalase system by controlling the cellular redox state through replenishing reduced glutathione. Overall, alternative biochemical regulation of the glyoxalase system mediated by insulin signaling or molecules like biguanides may control cellular MG homeostasis.

scholarly journals Effects of cellular ATP depletion on glucose transport and insulin signaling in 3T3-L1 adipocytes

2001 ◽  
Vol 280 (3) ◽  
pp. E428-E435 ◽  
Author(s):  
Jione Kang ◽  
Emma Heart ◽  
Chin K. Sung
Keyword(s):  
Insulin Resistance ◽  
Glucose Transport ◽  
Insulin Signaling ◽  
Atp Depletion ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Insulin Stimulation ◽  
Glut 1 ◽  
Induce Insulin Resistance ◽  
In Cells

Glucosamine induced insulin resistance in 3T3-L1 adipocytes, which was associated with a 15% decrease in cellular ATP content. To study the role of ATP depletion in insulin resistance, we employed sodium azide (NaN3) and dinitrophenol (DNP), which affect mitochondrial oxidative phosphorylation, to achieve a similar 15% ATP depletion. Unlike glucosamine, NaN3 and DNP markedly increased basal glucose transport, and the increased basal glucose transport was associated with increased GLUT-1 content in the plasma membrane without changes in total GLUT-1 content. These agents, like glucosamine, did not affect the early insulin signaling that is implicated in insulin stimulation of glucose transport. In cells with a severe 40% ATP depletion, basal glucose transport was similarly elevated, and insulin-stimulated glucose transport was similar in cells with 15% ATP depletion. In these cells, however, early insulin signaling was severely diminished. These data suggest that cellular ATP depletion by glucosamine, NaN3, and DNP exerts differential effects on basal and insulin-stimulated glucose transport and that ATP depletion per se does not induce insulin resistance in 3T3-L1 adipocytes.

scholarly journals Hydrogen Peroxide Generated during Cellular Insulin Stimulation Is Integral to Activation of the Distal Insulin Signaling Cascade in 3T3-L1 Adipocytes

2001 ◽  
Vol 276 (52) ◽  
pp. 48662-48669 ◽  
Author(s):  
Kalyankar Mahadev ◽  
Xiangdong Wu ◽  
Assaf Zilbering ◽  
Li Zhu ◽  
J. Todd R. Lawrence ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Insulin Signaling ◽  
Signaling Cascade ◽  
Insulin Stimulation

scholarly journals Reactive Oxygen Species-Mediated Control of Mitochondrial Biogenesis

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Edgar D. Yoboue ◽  
Anne Devin
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Biogenesis ◽  
Redox State ◽  
Mitochondrial Genomes ◽  
Oxygen Species ◽  
Mitochondrial Content ◽  
Cellular Redox ◽  
High Importance ◽  
Complex Process ◽  
Long Time

Mitochondrial biogenesis is a complex process. It necessitates the contribution of both the nuclear and the mitochondrial genomes and therefore crosstalk between the nucleus and mitochondria. It is now well established that cellular mitochondrial content can vary according to a number of stimuli and physiological states in eukaryotes. The knowledge of the actors and signals regulating the mitochondrial biogenesis is thus of high importance. The cellular redox state has been considered for a long time as a key element in the regulation of various processes. In this paper, we report the involvement of the oxidative stress in the regulation of some actors of mitochondrial biogenesis.

scholarly journals Cellular Redox State Acts as Switch to Determine the Direction of NNT-Catalyzed Reaction in Cystic Fibrosis Cells

2021 ◽  
Vol 22 (2) ◽  
pp. 967
Author(s):  
Maria Favia ◽  
Anna Atlante
Keyword(s):  
Cystic Fibrosis ◽  
Redox State ◽  
Molecular Mechanisms ◽  
Activity Level ◽  
Cellular Redox ◽  
Redox States ◽  
Mitochondrial Ros ◽  
New Information ◽  
Cellular Dysfunction ◽  
Cellular Redox State

The redox states of NAD and NADP are linked to each other in the mitochondria thanks to the enzyme nicotinamide nucleotide transhydrogenase (NNT) which, by utilizing the mitochondrial membrane potential (mΔΨ), catalyzes the transfer of redox potential between these two coenzymes, reducing one at the expense of the oxidation of the other. In order to define NNT reaction direction in CF cells, NNT activity under different redox states of cell has been investigated. Using spectrophotometric and western blotting techniques, the presence, abundance and activity level of NNT were determined. In parallel, the levels of NADPH and NADH as well as of mitochondrial and cellular ROS were also quantified. CF cells showed a 70% increase in protein expression compared to the Wt sample; however, regarding NNT activity, it was surprisingly lower in CF cells than healthy cells (about 30%). The cellular redox state, together with the low mΔΨ, pushes to drive NNT reverse reaction, at the expense of its antioxidant potential, thus consuming NADPH to support NADH production. At the same time, the reduced NNT activity prevents the NADH, produced by the reaction, from causing an explosion of ROS by the damaged respiratory chain, in accordance with the reduced level of mitochondrial ROS in NNT-loss cells. This new information on cellular bioenergetics represents an important building block for further understanding the molecular mechanisms responsible for cellular dysfunction in cystic fibrosis.

Effects of homocysteine on endothelial nitric oxide production

2000 ◽  
Vol 279 (4) ◽  
pp. F671-F678 ◽  
Author(s):  
Xiaohui Zhang ◽  
Hong Li ◽  
Haoli Jin ◽  
Zachary Ebin ◽  
Sergey Brodsky ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Redox State ◽  
Calcium Ionophore ◽  
No Production ◽  
Cellular Redox ◽  
A Cell ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Peroxynitrite Scavengers

Hyperhomocysteinemia (HHCy) is an independent and graded cardiovascular risk factor. HHCy is prevalent in patients with chronic renal failure, contributing to the increased mortality rate. Controversy exists as to the effects of HHCy on nitric oxide (NO) production: it has been shown that HHCy both increases and suppresses it. We addressed this problem by using amperometric electrochemical NO detection with a porphyrinic microelectrode to study responses of endothelial cells incubated with homocysteine (Hcy) to the stimulation with bradykinin, calcium ionophore, or l-arginine. Twenty-four-hour preincubation with Hcy (10, 20, and 50 μM) resulted in a gradual decline in responsiveness of endothelial cells to the above stimuli. Hcy did not affect the expression of endothelial nitric oxide synthase (eNOS), but it stimulated formation of superoxide anions, as judged by fluorescence of dichlorofluorescein, and peroxynitrite, as detected by using immunoprecipitation and immunoblotting of proteins modified by tyrosine nitration. Hcy did not directly affect the ability of recombinant eNOS to generate NO, but oxidation of sulfhydryl groups in eNOS reduced its NO-generating activity. Addition of 5-methyltetrahydrofolate restored NO responses to all agonists tested but affected neither the expression of the enzyme nor formation of nitrotyrosine-modified proteins. In addition, a scavenger of peroxynitrite or a cell-permeant superoxide dismutase mimetic reversed the Hcy-induced suppression of NO production by endothelial cells. In conclusion, electrochemical detection of NO release from cultured endothelial cells demonstrated that concentrations of Hcy >20 μM produce a significant indirect suppression of eNOS activity without any discernible effects on its expression. Folates, superoxide ions, and peroxynitrite scavengers restore the NO-generating activity to eNOS, collectively suggesting that cellular redox state plays an important role in HCy-suppressed NO-generating function of this enzyme.

A Novel Redox Based Therapy Targets the Malignant Cellular Redox State

2016 ◽  
Vol 100 ◽  
pp. S119 ◽  
Author(s):  
Dustin Carroll ◽  
Yanming Zhao ◽  
Haining Zhu ◽  
Ines Batinic-Haberle ◽  
Daret St. Clair
Keyword(s):  
Redox State ◽  
Cellular Redox ◽  
Therapy Targets ◽  
Cellular Redox State
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