scholarly journals Interleukin 1β and cAMP trigger the expression of GTP cyclohydrolase I in rat renal mesangial cells

1996 ◽  
Vol 318 (2) ◽  
pp. 665-671 ◽  
Author(s):  
Christoph PLÜSS ◽  
Ernst R. WERNER ◽  
Nenad BLAU ◽  
Helmut WACHTER ◽  
Josef PFEILSCHIFTER
Keyword(s):  
Half Life ◽  
Mesangial Cells ◽  
Interleukin 1Β ◽  
No Production ◽  
Mrna Levels ◽  
Gtp Cyclohydrolase I ◽  
Gtp Cyclohydrolase ◽  
Protein Levels ◽  
Rabbit Polyclonal Antibody ◽  
Stimulation Of

Endogenous synthesis of tetrahydrobiopterin (BH4) is an important requirement for cytokine-stimulated nitric oxide (NO) production in mesangial cells. We have shown that inducible NO synthase is expressed in mesangial cells in response to two principal classes of activating signals, inflammatory cytokines such as interleukin 1β (IL-1β) and agents that elevate cellular levels of cAMP [Kunz, Mühl, Walker and Pfeilschifter (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 5387–5391]. In the present paper we demonstrate that IL-1β and cAMP similarly increase the steady-state mRNA levels of GTP cyclohydrolase I (EC 3.5.4.16), the rate-limiting enzyme in BH4 biosynthesis, as measured by a sensitive and quantitative nuclease protection assay. Stimulation of cells with a combination of IL-1β plus cAMP revealed an additive induction profile of GTP cyclohydrolase I mRNA. Message stability studies established that GTP cyclohydrolase I mRNA induced by cAMP has a longer half-life than the IL-1β-induced message. Moreover, cAMP exposure markedly prolonged the half-life of GTP cyclohydrolase I mRNA, from 1.5 to 3.4 h. In a next step we generated a rabbit polyclonal antibody against rat GTP cyclohydrolase I expressed in Escherichia coli and demonstrated that IL-1β and cAMP elevated GTP cyclohydrolase I protein levels in mesangial cells. Furthermore, IL-1β and cAMP led to a marked increase in GTP cyclohydrolase I activity and to increased accumulation of biopterin in mesangial cells. Combinations of IL-1β and cAMP resulted in a synergistic stimulation of GTP cyclohydrolase I activity. This may suggest that, in addition to transcriptional and post-transcriptional regulation, there is a prominent post-translational modulation of enzyme activity.

scholarly journals Nitric oxide formation in acutely rejecting cardiac allografts correlates with GTP cyclohydrolase I activity

2005 ◽  
Vol 391 (3) ◽  
pp. 541-547 ◽  
Author(s):  
Galen M. Pieper ◽  
Vani Nilakantan ◽  
Nadine L. N. Halligan ◽  
Ashwani K. Khanna ◽  
Gail Hilton ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Graft Rejection ◽  
Ex Vivo ◽  
No Production ◽  
Gtp Cyclohydrolase I ◽  
Gtp Cyclohydrolase ◽  
Protein Levels ◽  
Acute Graft Rejection ◽  
Cardiac Allografts ◽  
Acute Graft

Inducible nitric oxide synthase (iNOS) is a prominent component of the complex array of mediators in acute graft rejection. While NO production is determined by iNOS expression, BH4 (tetrahydrobiopterin), a cofactor of iNOS synthesized by GTP cyclohydrolase I, has been considered critical in sustaining NO production. In the present study, we examined time-dependent changes in iNOS and GTP cyclohydrolase I in rat cardiac allografts. The increase in iNOS protein and mRNA in allografts was similar at POD4 (post-operative day 4) and POD6. However, the peak increase in intragraft NO level at POD4 was not sustained at POD6. This disparity could not be explained by any decrease in iNOS enzyme activity measured ex vivo with optimal amounts of substrate and cofactors. Lower iNOS activity could be explained by changes in total biopterin levels in allografts at POD4 that was decreased to baseline at POD6. Changes in biopterin production correlated with lower GTP cyclohydrolase I protein levels but not by any change in GTP cyclohydrolase I mRNA. Functionally, allografts displayed bradycardia and distended diastolic and systolic dimensions at POD6 but not at POD4. Likewise, histological rejection scores were increased at POD4 but with a secondary increased stage at POD6. It is hypothesized that the dissimilar amounts of NO at early and later stages of rejection is due to uncoupling of iNOS arising from disproportionate synthesis of BH4. These findings provide insight into a potential pathway regulating NO bioactivity in graft rejection. Such knowledge may potentially assist in the design of newer strategies to prevent acute graft rejection.

Statin Increases GTP Cyclohydrolase I mRNA and 5,6,7,8-Tetrahydrobiopterin in Vascular Endothelial Cells

Pteridines ◽  
2006 ◽  
Vol 17 (3) ◽  
pp. 65-68
Author(s):  
Yoshiyuki Hattori ◽  
Nobuo Nakanishi
Keyword(s):  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
Umbilical Vein ◽  
No Production ◽  
Mrna Levels ◽  
Gtp Cyclohydrolase I ◽  
Gtp Cyclohydrolase ◽  
Reductase Inhibitors ◽  
Enos Mrna ◽  
The Stability

Abstract We investigated the effects of HMG-CoA reductase inhibitors, so-called statins, on 5,6,7,8-tctrahydrobioptcrin (BH4) metabolism in human umbilical vein endothelial cells (HUVEC). The mRNA of GTP cyclohydrolase I (GTPCH), as well as cNOS, was upregulated in HUVEC treated with cerivastatin. This increase was time- and dose-dependent. Fluvastatin was also observed to enhance GTPCH and eNOS mRNA levels. In parallel with this observation, cerivastatin increased intracellular BH4. Cerivastatin increased the stability of eNOS mRNA. However, it did not alter the stability of GTPCH mRNA but increased GTPCH gene transcription as shown by nuclear run-on assays. Preteatment of HUVEC with the selective GTPCH inhibitor, 2,4-diamino-6-hydroxypyrimidine, caused a decrease in intracellular BH4 and decreased citrulline formation following stimulation with ionomycin. Furthermore, the potentiating effect of cerivasatin was decreased by limiting the cellular availability of BH4. In addition to augmenting eNOS expression, statins potentiate GTPCH gene expression and BH4 synthesis, thereby increasing NO production and preventing relative shortages of BH4

Impaired nitric oxide production in coronary endothelial cells of the spontaneously diabetic BB rat is due to tetrahydrobiopterin deficiency

2000 ◽  
Vol 349 (1) ◽  
pp. 353-356 ◽  
Author(s):  
Cynthia J. MEININGER ◽  
Rebecca S. MARINOS ◽  
Kazuyuki HATAKEYAMA ◽  
Raul MARTINEZ-ZAGUILAN ◽  
Jose D. ROJAS ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
De Novo ◽  
Diabetic Rats ◽  
Bb Rat ◽  
No Production ◽  
Gtp Cyclohydrolase I ◽  
Gtp Cyclohydrolase ◽  
Bb Rats ◽  
Metabolic Basis ◽  
Rate Limiting

Endothelial cells (EC) from diabetic BioBreeding (BB) rats have an impaired ability to produce NO. This deficiency is not due to a defect in the constitutive isoform of NO synthase in EC (ecNOS) or alterations in intracellular calcium, calmodulin, NADPH or arginine levels. Instead, ecNOS cannot produce sufficient NO because of a deficiency in tetrahydrobiopterin (BH4), a cofactor necessary for enzyme activity. EC from diabetic rats exhibited only 12% of the BH4 levels found in EC from normal animals or diabetes-prone animals which did not develop disease. As a result, NO synthesis by EC of diabetic rats was only 18% of that for normal animals. Increasing BH4 levels with sepiapterin increased NO production, suggesting that BH4 deficiency is a metabolic basis for impaired endothelial NO synthesis in diabetic BB rats. This deficiency is due to decreased activity of GTP-cyclohydrolase I, the first and rate-limiting enzyme in the de novo biosynthesis of BH4. GTP-cyclohydrolase activity was low because of a decreased expression of the protein in the diabetic cells.

scholarly journals Stimulation of GTP Cyclohydrolase I by Phosphorylation Upon T Cell Activation

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Wei Chen ◽  
Li Li ◽  
Torben Brod ◽  
Omar Saeed ◽  
Serguei Dikalov ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Gtp Cyclohydrolase I ◽  
Gtp Cyclohydrolase ◽  
Stimulation Of

Endothelin-1 Inhibits Induction of Nitric Oxide Synthase and GTP Cyclohydrolase I in Rat Mesangial Cells

Pharmacology ◽  
1996 ◽  
Vol 53 (4) ◽  
pp. 241-249 ◽  
Author(s):  
Junichi Hirahashi ◽  
Toshio Nakaki ◽  
Keiichi Hishikawa ◽  
Takeshi Marumo ◽  
Toshio Yasumori ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Mesangial Cells ◽  
Gtp Cyclohydrolase I ◽  
Gtp Cyclohydrolase ◽  
Endothelin 1 ◽  
Oxide Synthase

Role of PKCα in feedback regulation of Na+transport in an electrically tight epithelium

2002 ◽  
Vol 283 (4) ◽  
pp. C1122-C1132 ◽  
Author(s):  
Mouhamed S. Awayda ◽  
Justin D. Platzer ◽  
Roxanne L. Reger ◽  
Abderrahmane Bengrine
Keyword(s):  
Steady State ◽  
Blot Analysis ◽  
Feedback Regulation ◽  
Feedback Mechanism ◽  
Mrna Levels ◽  
Protein Levels ◽  
Pkc Isoforms ◽  
A6 Epithelia ◽  
Tight Epithelia ◽  
Stimulation Of

It has long been known that Na+ channels in electrically tight epithelia are regulated by homeostatic mechanisms that maintain a steady state and allow new levels of transport to be sustained in hormonally challenged cells. Little is known about the potential pathways involved in these processes. In addition to short-term effect, recent evidence also indicates the involvement of PKC in the long-term regulation of the epithelial Na+ channel (ENaC) at the protein level (40). To determine whether stimulation of ENaC involves feedback regulation of PKC levels, we utilized Western blot analysis to determine the distribution of PKC isoforms in polarized A6 epithelia. We found the presence of PKC isoforms in the conventional (α and γ), novel (δ, η, and ε), and atypical (ι, λ, and ζ) groups. Steady-state stimulation of Na+ transport with aldosterone was accompanied by a specific decrease of PKCα protein levels in both the cytoplasmic and membrane fractions. Similarly, overnight treatment with an uncharged amiloride analog (CDPC), a procedure that through feedback regulation causes a stimulation of Na+ transport, also decreased PKCα levels. These effects were additive, indicating separate mechanisms that converge at the level of PKCα. These effects were not accompanied by changes of PKCα mRNA levels as determined by Northern blot analysis. We propose that this may represent a novel regulatory feedback mechanism necessary for sustaining an increase of Na+ transport.

scholarly journals Relaxin Stimulates Protein Kinase C ζ Translocation: Requirement for Cyclic Adenosine 3′,5′-Monophosphate Production

2005 ◽  
Vol 19 (4) ◽  
pp. 1012-1023 ◽  
Author(s):  
Bao T. Nguyen ◽  
Carmen W. Dessauer
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Time Course ◽  
Kinase Inhibitors ◽  
Mesangial Cells ◽  
Camp Production ◽  
Protein Levels ◽  
Kinase C ◽  
Phosphoinositide 3 Kinase ◽  
Stimulation Of

Abstract Relaxin is a polypeptide hormone that activates the leucine-rich repeat containing G protein-coupled receptors, LGR7 and LGR8. In an earlier study, we reported that relaxin produces a biphasic time course and the second wave of cAMP is highly sensitive to phosphoinositide-3 kinase inhibitors (LY294002 and wortmannin). LY294002 inhibits relaxin-mediated increases in cAMP production by 40–50% across a large range of relaxin concentrations. Here we show that protein kinase C ζ (PKCζ) is a component of relaxin signaling in THP-1 cells. Sphingomyelinase increases cAMP production due to the release of ceramide, a direct activator of PKCζ. Chelerythrine chloride (a general PKC inhibitor) inhibits relaxin induced cAMP production to the same degree (∼40%) as LY294002. Relaxin stimulates PKCζ translocation to the plasma membrane in THP-1, MCF-7, pregnant human myometrial 1–31, and mouse mesangial cells, as shown by immunocytochemistry. PKCζ translocation is phosphoinositide-3 kinase dependent and independent of cAMP production. Antisense PKCζ oligodeoxynucleotides (PKCζ-ODNs) deplete both PKCζ transcript and protein levels in THP-1 cells. PKCζ-ODNs abolish relaxin-mediated PKCζ translocation and inhibit relaxin stimulation of cAMP by 40%, as compared with mock and random ODN controls. Treatment with LY294002 in the presence of PKCζ-ODNs results in little further inhibition. In summary, we present a novel role for PKCζ in relaxin-mediated stimulation of cAMP.

scholarly journals Regulation of Inhibitor of Apoptosis Expression by Nitric Oxide and Cytokines: Relation to Apoptosis Induction in Rat Mesangial Cells and RAW 264.7 Macrophages

2001 ◽  
Vol 12 (6) ◽  
pp. 1151-1163
Author(s):  
MARKUS MANDERSCHEID ◽  
UDO K. MEßMER ◽  
ROCHUS FRANZEN ◽  
JOSEF PFEILSCHIFTER
Keyword(s):  
Mesangial Cells ◽  
Inhibitor Of Apoptosis ◽  
No Production ◽  
Raw 264.7 ◽  
Apoptosis Induction ◽  
No Donors ◽  
Raw 264.7 Macrophages ◽  
Protein Levels ◽  
Factor Α ◽  
Necrosis Factor

Abstract. Mesangial cells and RAW 264.7 macrophages respond to different nitric oxide (NO) donors within 16 to 24 h or 6 to 8 h, respectively, with apoptotic cell death. RAW 264.7 macrophages also die in response to endogenous NO production. In contrast, endogenous NO production fails to significantly induce cell death in mesangial cells. It was hypothesized that differences in the expression of antiapoptotic proteins, in particular the inhibitor of apoptosis (IAP) protein family, might be responsible for this cell type-specific behavior. Therefore, IAP expression was investigated in relation to apoptosis induction in response to NO and cytokines in both cell types. In mesangial cells, interleukin-1β (IL-1β) and tumor necrosis factor-α induced cellular inhibitor of apoptosis 1 (cIAP1) mRNA expression within 3 h. In contrast, X chromosome-linked inhibitor of apoptosis (XIAP) mRNA levels remained unaffected by cytokines. Although coincubation of cells with IL-1β and tumor necrosis factor-α or IL-1β and basic fibroblast growth factor resulted in synergistic induction of inducible NO synthase, comparable potentiating effects on cIAP1 induction were absent. Exogenously released NO from NO donors promoted cIAP1 mRNA upregulation in mesangial cells, whereas XIAP mRNA was downregulated. However, the changes observed on the mRNA level were not adequately translated to the protein level, and corresponding values for cIAP1 and XIAP were only slightly affected. In contrast, in lipopolysaccharide/interferon-γ-stimulated RAW 264.7 macrophages, massive NO-dependent downregulation of cIAP1 and XIAP protein levels, which correlated temporally with the induction of apoptosis, was observed. This effect was at least partially reversed by NG-monomethyl-L-arginine, an inhibitor of NO synthase activity. In summary, a direct correlation between the downregulation of IAP protein levels and the induction of apoptosis by endogenous NO was observed in macrophages. In contrast, a stable level of IAP protein in mesangial cells might represent a mechanism for the resistance of the cells to endogenously produced NO.

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