Circadian tracking of nicotinamide cofactor levels in an immortalized suprachiasmatic nucleus cell line

Wise, Dana D.; Shear, Jason B.

doi:10.1016/j.neuroscience.2004.06.058

Cited by 11 publications

(8 citation statements)

References 22 publications

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“…The role of NADK1 is likely to supply NADP to the cytosol and potentially to organelles considered permeable to NADP or capable of NAD(P) transport such as the nucleus, endoplasmic reticulum, Golgi, and mitochondrion (Navas et al 1986;Bublitz and Lawler, 1987;Wise and Shear, 2004;Todisco et al 2006). Recently, Pollak et al (2007) showed that manipulation of human cytosolic NADK activity correspondingly altered NADPH levels and affected cellular resistance to exogenous reactive oxygen species (ROS).…”

Section: Nadk1 Is a Cytosolic Enzyme Expressed Mainly In Rootsmentioning

confidence: 99%

Subcellular and tissue localization of NAD kinases from Arabidopsis: compartmentalization of de novo NADP biosynthesis

Waller

Dhanoa

Schümann

et al. 2009

Planta

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The de novo biosynthesis of the triphosphopyridine NADP is catalyzed solely by the ubiquitous NAD kinase family. The Arabidopsis (Arabidopsis thaliana) genome contains two genes encoding NAD+ kinases (NADKs), annotated as NADK1, NADK2, and one gene encoding a NADH kinase, NADK3, the latter isoform preferring NADH as a substrate. Here, we examined the tissue-specific and developmental expression patterns of the three NADKs using transgenic plants stably transformed with NADK promoter::glucuronidase (GUS) reporter gene constructs. We observed distinct spatial and temporal patterns of GUS activity among the NADK::GUS plants. All three NADK::GUS transgenes were expressed in reproductive tissue, whereas NADK1::GUS activity was found mainly in the roots, NADK2::GUS in leaves, and NADK3::GUS was restricted primarily to leaf vasculature and lateral root primordia. We also examined the subcellular distribution of the three NADK isoforms using NADK-green fluorescent protein (GFP) fusion proteins expressed transiently in Arabidopsis suspension-cultured cells. NADK1 and NADK2 were found to be localized to the cytosol and plastid stroma, respectively, consistent with previous work, whereas NADK3 localized to the peroxisomal matrix via a novel type 1 peroxisomal targeting signal. The specific subcellular and tissue distribution profiles among the three NADK isoforms and their possible non-overlapping roles in NADP(H) biosynthesis in plant cells are discussed.

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Section: Nadk1 Is a Cytosolic Enzyme Expressed Mainly In Rootsmentioning

confidence: 99%

Subcellular and tissue localization of NAD kinases from Arabidopsis: compartmentalization of de novo NADP biosynthesis

Waller

Dhanoa

Schümann

et al. 2009

Planta

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“…Whether these properties have physiological relevance in all brain cells or only in more specialized subpopulations is not known yet. Incidentally, the modulating effect of redox state, at least in cultured SCN cells, is not salient (Wise & Shear, 2004).…”

Section: Mice Lacking Specific Clock Genesmentioning

confidence: 99%

Neurogenetics of food anticipation

Challet

Mendoza

Dardente

et al. 2009

Eur J of Neuroscience

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Circadian clocks enable the organisms to anticipate predictable cycling events in the environment. The mechanisms of the main circadian clock, localized in the suprachiasmatic nuclei of the hypothalamus, involve intracellular autoregulatory transcriptional loops of specific genes, called clock genes. In the suprachiasmatic clock, circadian oscillations of clock genes are primarily reset by light, thus allowing the organisms to be in phase with the light-dark cycle. Another circadian timing system is dedicated to preparing the organisms for the ongoing meal or food availability: the so-called food-entrainable system, characterized by food-anticipatory processes depending on a circadian clock whose location in the brain is not yet identified with certainty. Here we review the current knowledge on food anticipation in mice lacking clock genes or feeding-related genes. The food-entrainable clockwork in the brain is currently thought to be made of transcriptional loops partly divergent from those described in the light-entrainable suprachiasmatic nuclei. Possible confounding effects associated with behavioral screening of meal anticipation in mutant mice are also discussed.

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“…Mitochondrial ATP‐sensitive K + channel activation increases the cytochrome C release from the mitochondria to cytosol (Xu et al,2001; Schurr,2006). Glucose deprivation and ATP usage deplete NADH level, and oxidative stress or biosynthetic demands deplete NADPH stores (Wise and Shear,2004; Schurr,2006). Because glucose uptake and usage increase with cellular activity, and SCN cells exhibit cyclic daily glucose consumption, a circadian rhythm in the ratio of reduced NAD(P)H to their oxidized counterparts NAD(P) might be expected to increase during the light period.…”

Section: Discussionmentioning

confidence: 99%

Circadian rhythm of metabolic oscillation in suprachiasmatic nucleus depends on the mitochondrial oxidation state, reflected by cytochrome C oxidase and lactate dehydrogenase

2011

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Metabolic activity in the suprachiasmatic nucleus (SCN), a center of biological rhythm, is higher during the daytime than at night. The rhythmic oscillation in the SCN is feedback controlled by the Clock/Bmal1 heterodimer binding to the E-box in target genes (e.g., Arg-vasopressin). Similar transcriptional regulation by Npas2/Bmal1 heterodimer formation operates in the brain, which is dependent on the redox state (i.e., NAD/NADH). To clarify the metabolic function of SCN in relation to the redox state and glycolysis levels, we measured glucose, lactate dehydrogenase (LDH), LDH mRNA, and cytochrome C oxidase, energy-producing biochemical materials from mitochondria/cytosol, in rats kept under a light-dark cycle. Mitochondrial cytochrome C oxidase activity, measured by the changes in absorption at 550 nm, was higher during the light period than during the dark period. Glucose concentration was higher during the light period. In contrast, LDH and its coding mRNA were higher during the dark period. Mitochondrial aggregation, which is reflected by mitochondrial membrane potential, indexed by JC-1 fluorescence, was higher during the light period. The results indicate that the glycolysis energy pathway in the SCN, which exhits higher metabolic activity during the day than at night, might be involved in the generation of circadian rhythm.

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Circadian tracking of nicotinamide cofactor levels in an immortalized suprachiasmatic nucleus cell line

Cited by 11 publications

References 22 publications

Subcellular and tissue localization of NAD kinases from Arabidopsis: compartmentalization of de novo NADP biosynthesis

Subcellular and tissue localization of NAD kinases from Arabidopsis: compartmentalization of de novo NADP biosynthesis

Neurogenetics of food anticipation

Circadian rhythm of metabolic oscillation in suprachiasmatic nucleus depends on the mitochondrial oxidation state, reflected by cytochrome C oxidase and lactate dehydrogenase

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