scholarly journals Inositol hexakisphosphate kinase-2 determines cellular energy dynamics by regulating creatine kinase-B

2021 ◽  
Vol 118 (6) ◽  
pp. e2020695118
Author(s):  
Latika Nagpal ◽  
Michael D. Kornberg ◽  
Lauren K. Albacarys ◽  
Solomon H. Snyder

Inositol hexakisphosphate kinases (IP6Ks) regulate various biological processes. IP6Ks convert IP6 to pyrophosphates such as diphosphoinositol pentakisphosphate (IP7) and bis-diphosphoinositol tetrakisphosphate (IP8). IP7 is produced in mammals by a family of inositol hexakisphosphate kinases, IP6K1, IP6K2, and IP6K3, which have distinct biological functions. The inositol hexakisphosphate kinase 2 (IP6K2) controls cellular apoptosis. To explore roles for IP6K2 in brain function, we elucidated its protein interactome in mouse brain revealing a robust association of IP6K2 with creatine kinase-B (CK-B), a key enzyme in energy homeostasis. Cerebella of IP6K2-deleted mice (IP6K2-knockout [KO]) produced less phosphocreatine and ATP and generated higher levels of reactive oxygen species and protein oxidative damage. In IP6K2-KO mice, mitochondrial dysfunction was associated with impaired expression of the cytochrome-c1 subunit of complex III of the electron transport chain. We reversed some of these effects by combined treatment with N-acetylcysteine and phosphocreatine. These findings establish a role for IP6K2–CK-B interaction in energy homeostasis associated with neuroprotection.

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1318.2-1318
Author(s):  
H. R. Lee ◽  
S. J. Yoo ◽  
J. Kim ◽  
I. S. Yoo ◽  
C. K. Park ◽  
...  

Background:Reactive oxygen species (ROS) and T helper 17 (TH17) cells have been known to play an important role in the pathogenesis of rheumatoid arthritis (RA). However, the interrelationship between ROS and TH17 remains unclear in RAObjectives:To explore whether ROS affect TH17 cells in peripheral blood mononuclear cells (PBMC) of RA patients, we analyzed ROS expressions among T cell subsets following treatment with mitochondrial electron transport chain complex inhibitors.Methods:Blood samples were collected from 40 RA patients and 10 healthy adult volunteers. RA activity was divided according to clinical parameter DAS28. PBMC cells were obtained from the whole blood using lymphocyte separation medium density gradient centrifugation. Following PBMC was stained with Live/Dead stain dye, cells were incubated with antibodies for CD3, CD4, CD8, and CD25. After fixation and permeabilization, samples were stained with antibodies for FoxP3 and IL-17A. MitoSox were used for mitochondrial specific staining.Results:The frequency of TH17 cells was increased by 4.83 folds in moderate disease activity group (5.1>DAS28≥3.2) of RA patients compared to healthy control. Moderate RA activity patients also showed higher ratio of TH17/Treg than healthy control (3.57 folds). All RA patients had elevated expression of mitochondrial specific ROS than healthy control. When PBMC cells were treated with 2.5uM of antimycin A (mitochondrial electron transport chain complex III inhibitor) for 16 h, the frequency of TH17 cells was significantly decreased.Conclusion:The mitochondrial electron transport chain complex III inhibitor markedly downregulated the frequency of TH17 cells in moderate disease activity patients with RA. These findings provide a novel approach to regulate TH17 function in RA through mitochondrial metabolism related ROS production.References:[1]Szekanecz, Z., et al., New insights in synovial angiogenesis. Joint Bone Spine, 2010. 77(1): p. 13-9.[2]Prevoo, M.L., et al., Modified disease activity scores that include twenty-eight-joint counts. Development and validation in a prospective longitudinal study of patients with rheumatoid arthritis. Arthritis Rheum, 1995. 38(1): p. 44-8.Disclosure of Interests:None declared


1993 ◽  
Vol 264 (6) ◽  
pp. C1600-C1608 ◽  
Author(s):  
T. Sandouk ◽  
D. Reda ◽  
C. Hofmann

Adipocytes play an important role in normal physiology as a major site for systemic energy homeostasis. In disorders such as diabetes, adipocyte function is markedly altered. In this study, we investigated the effect of pioglitazone, a novel antidiabetic agent known to lower plasma glucose in animal models of diabetes mellitus, on cellular differentiation and expression of adipose-specific genes. Treatment of confluent 3T3-F442A preadipocyte cultures for 7 days with pioglitazone (Pio; 1 microM) and insulin (Ins; 0.17 microM) resulted in > 95% cell differentiation into lipid-accumulating adipocytes in comparison with 60-80% cell differentiation by treatment with either agent alone. Analysis of triglyceride accumulation showed increases of triglyceride content over time above untreated preadipocytes by treatment of the cells with Ins, Pio, and especially with Ins + Pio. Basal glucose transport, as measured by cellular uptake of 2-deoxy-D-[14C]glucose, was likewise enhanced in a time-dependent manner by treatment of preadipocytes with Ins, Pio, or Ins + Pio, such that a synergistic effect resulted from the combined treatment with both agents. It was further determined that RNA transcript abundance for genes encoding glucose transporters GLUT-1 and GLUT-4, as well as the adipose-specific genes encoding adipsin and aP2, were increased by the Ins, Pio, or Ins + Pio treatment. Taken together, these findings indicate that pioglitazone is a potent adipogenic agent. By promoting differentiation, this agent may move cells into a state active for glucose uptake, storage, and metabolism.


2006 ◽  
Vol 84 (2) ◽  
pp. 142-147
Author(s):  
Feng Shi ◽  
Tong-Jin Zhao ◽  
Hua-Wei He ◽  
Jie Li ◽  
Xian-Gang Zeng ◽  
...  

As a depressant of the central nervous system, the clinical effect of sodium barbital has been extensively studied. Here we report on sodium barbital as an inhibitor of rabbit-muscle creatine kinase (CK), which plays a significant role in energy homeostasis in the muscles. Although sodium barbital gradually inhibits the activity of CK with increased concentration, the inhibition effect can be completely reversed by dilution, indicating that the inactivation process is reversible. Detailed kinetics analysis, according to a previously presented theory, indicates that sodium barbital functions as a non complexing inhibitor, and its inhibition effect on CK is a slow reversible inactivation. In this study, a kinetic model of the substrate reaction is presented, and the microscopic rate constants for the reaction of sodium barbital with the free enzyme and the enzyme–substrate complexes are determined. Kinetic analysis reveals that sodium barbital might compete with both creatine and ATP, but mainly with creatine, to inhibit the activity of CK. The results suggest that CK might be a target for sodium barbital in vivo.Key words: creatine kinase; inactivation; kinetics; sodium barbital.


2017 ◽  
Vol 45 ◽  
pp. 100-104 ◽  
Author(s):  
Joseph Kilianski ◽  
Sophie Peeters ◽  
Jeff Debad ◽  
Joseph Mohmed ◽  
Steven E. Wolf ◽  
...  

Author(s):  
Ivan Weinsanto ◽  
Jinane Mouheiche ◽  
Alexis Laux-Biehlmann ◽  
François Delalande ◽  
Arnaud Marquette ◽  
...  

1981 ◽  
Vol 101 (5) ◽  
pp. 561-569 ◽  
Author(s):  
Michael H. Burnam ◽  
Marisa A. Crouch ◽  
Christopher Y.C. Chew ◽  
Winifred Carnegie ◽  
Harvey Hecht ◽  
...  

Author(s):  
Zhou Yu ◽  
Sufang Sun ◽  
Fang Hu

IntroductionMyocardial ischaemia/reperfusion (I/R) injury is the leading cause of morbidity and mortality worldwide. Despite novel advances in therapeutics, the management of myocardial I/R is still an unmet medical need. Therefore, in the present study, we have demonstrated the protective effect of ropivacaine (RPC) on the myocardial infarction in rats and its underlying mechanism.Material and methodsInitially, the effect of RPC was determined on the infarct size and histopathology of cardiac tissues. The effect of RPC was also determined on the levels of various cardiac biomarkers such as creatine kinase (CK), creatine kinase MB (CK-MB), alanine aminotransferase (ALT), asparganine aminotransferase (AST), and lactate dehydrogenase (LDH), and biomarkers of oxidative stress (MDA, SOD, and GSH) and inflammation (tumour necrosis factor-α (TNF-α), interleukin 1β (IL-1β), and IL-6). RPC effect was also quantified on cellular apoptosis and COX-2 and iNOS expression via western blot analysis. The RPC was further docked into the active site of COX-2.ResultsIt has been found that RPC reduces the improves haemodynamics of (LVSP and ± dp/dtmax, and LVEDP), infarct percentage and architecture of cardiac tissues of rats. It also reduces the level of studies cardiac injury biomarkers together with a reduction of oxidative stress (MDA, SOD, and GSH) and inflammation (TNF-α, IL-1β, and IL-6). Upon administration of RPC, the rate of cellular apoptosis was found to be greatly reduced, with a reduction in COX-2 and iNOS expression. In docking analysis, RPC creates van der Waals forces and pi-interactions with Tyr381, Arg106, Val102, Leu345, Val509, Ser339, Leu338, Val335, Ala513, His75, and Leu517 at the catalytic site of COX-2.ConclusionsCollectively, our results demonstrated that ropivacaine showed significant benefit against myocardial ischaemic injury.


2009 ◽  
Vol 83 (10) ◽  
pp. 5137-5147 ◽  
Author(s):  
Hiromichi Hara ◽  
Hideki Aizaki ◽  
Mami Matsuda ◽  
Fumiko Shinkai-Ouchi ◽  
Yasushi Inoue ◽  
...  

ABSTRACT Persistent infection with hepatitis C virus (HCV) is a major cause of chronic liver diseases. The aim of this study was to identify host cell factor(s) participating in the HCV replication complex (RC) and to clarify the regulatory mechanisms of viral genome replication dependent on the host-derived factor(s) identified. By comparative proteome analysis of RC-rich membrane fractions and subsequent gene silencing mediated by RNA interference, we identified several candidates for RC components involved in HCV replication. We found that one of these candidates, creatine kinase B (CKB), a key ATP-generating enzyme that regulates ATP in subcellular compartments of nonmuscle cells, is important for efficient replication of the HCV genome and propagation of infectious virus. CKB interacts with HCV NS4A protein and forms a complex with NS3-4A, which possesses multiple enzyme activities. CKB upregulates both NS3-4A-mediated unwinding of RNA and DNA in vitro and replicase activity in permeabilized HCV replicating cells. Our results support a model in which recruitment of CKB to the HCV RC compartment, which has high and fluctuating energy demands, through its interaction with NS4A is important for efficient replication of the viral genome. The CKB-NS4A association is a potential target for the development of a new type of antiviral therapeutic strategy.


Author(s):  
Vaibhav Walia ◽  
Munish Garg

Mitochondria are a dynamic organelle of the cell involved in the various biological processes. Mitochondria are the site of the adenosine triphosphate (ATP) production, electron transport chain (ETC), oxidation of fatty acids, tricarboxylic acid (TCA), and cellular apoptosis. Besides these, mitochondria are the site of production of reactive oxygen species (ROS), which further disrupts the normal functioning of this organelle also making mitochondria itself as an important target of oxidative stress. Thus, mitochondria serve as an important target in the process of neurodegeneration. In the present chapter, the authors describe mitochondria and its functioning, dynamics, and the mitochondrial dysfunction in aging and neurodegenerative disorders (NDs).


Enzyme ◽  
1989 ◽  
Vol 41 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Andrew F. G Quest ◽  
Hans M. Eppenberger ◽  
Theo Walliman

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