Stimulation of Arginine Transport and Nitric Oxide Production by Lipopolysaccharide Is Mediated by Different Signaling Pathways in Astrocytes

Schmidlin, Andreas; Wiesinger, Heinrich

doi:10.1046/j.1471-4159.1995.65020590.x

Cited by 40 publications

(16 citation statements)

References 16 publications

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“…In this study, inhibition of iNOS activity by AMT partially prevented LPS-mediated increase in transport activity (see also Ref. 35). As indicated by Cat1 mRNA levels, there was no modification in Cat1 expression in LPS-treated cells (see also Ref.…”

Section: Discussionsupporting

confidence: 58%

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Peroxynitrite Stimulates l-Arginine Transport Systemy+ in Glial Cells

Vega-Agapito¹,

Almeida²,

Hatzoglou³

et al. 2002

Journal of Biological Chemistry

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We have reported previously that peroxynitrite stimulates L-arginine release from astrocytes, but the mechanism responsible for such an effect remains elusive. To explore this issue, we studied the regulation of Glial cells can be activated to endogenously produce ⅐ NO through the induction of the inducible NOS isoform (iNOS) (9 -13). Within the brain, free L-arginine is predominantly located in astrocytes (14), which produce large amounts of ⅐ NO upon iNOS (15) and L-arginine transporter (7) induction. However, unlike in astrocytes, L-arginine content in neurons is very low and is limiting for nNOS activity (16,17). Consistent with this, glial-derived L-arginine has been shown to be increased upon activation of ionotropic glutamate (non-N-methyl-Daspartate) receptors (18) and peroxynitrite (19), suggesting a neuronal-astrocytic signaling transduction pathway focused to provide NOS substrate for the neurons. However, direct demonstration of such a pathway and the elucidation of the precise transport system involved remain elusive.Plasma membrane L-arginine transport is brought about by two families of cationic amino acid transport proteins: Cat (cationic amino acid transporter) and Bat (broad scope amino acid transporter). The Cat family of transporters comprises three different genes encoding four isoform proteins (Cat1, Cat2, Cat2a, and Cat3) (20, 21), commonly referred to as the system y ϩ (22), which is mostly selective for cationic amino acids, although it does show a weak interaction with neutral amino acids in the presence of Na ϩ (23). Glial cells mainly, but not exclusively, express the high affinity (k t for L-arginine ϭ 40 -250 M) (24) 67-kDa Cat1 (constitutive) (25) and the 71.8-kDa Cat2 (inducible) (26) system y ϩ proteins (7, 27). The Bat family of constitutive transporter proteins is found in systems b o,ϩ , B o,ϩ , and y ϩ L (y ϩ Lat1 and y ϩ Lat2), which are mainly expressed in kidney and intestine, except for y ϩ Lat2, which is expressed in astrocytes (28).We have reported previously that the neurotoxic ⅐ NO derivative, peroxynitrite anion (ONOO Ϫ ), specifically stimulates Larginine release from astrocytes (19). Although the ONOO Ϫ -mediated stimulatory effect was inhibited by L-lysine, hence suggesting the involvement of system y ϩ (19), an in-depth study focused on elucidating the precise mechanism responsible for L-arginine transport activation has not yet been carried out. In view of the potential critical role of glial cells as neuronal L-arginine suppliers for ⅐ NO biosynthesis (8,18,29), we were prompted to investigate the mechanism through which ONOO Ϫ modulates L-arginine transport across the glial cell plasma membrane as well as the potential relevance of such modulation for neuronal L-arginine uptake.* This work was funded by grants from the Ministerio de Ciencia y Tecnología (Grant SAF2001-1961), the Junta de Castilla y León (Grant SA065/01) and Fundación Ramón Areces (to J. P. B.), and Grant RO1 DK53307-01 (to M. H.).§ The recipient of a fellowship from the Fundación Miguel Casado...

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Section: Discussionsupporting

confidence: 58%

“…Controls were carried out using degraded ONOO Ϫ . In some experiments, neurons were depleted of L-arginine by incubating these cells in DMEM containing arginase (2 units/ml; Sigma) for 24 h as described previously (35) before the co-incubation with astrocytes.…”

mentioning

confidence: 99%

Peroxynitrite Stimulates l-Arginine Transport Systemy+ in Glial Cells

Vega-Agapito¹,

Almeida²,

Hatzoglou³

et al. 2002

Journal of Biological Chemistry

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“…In cultured astroglial cells, bacterial LPS and IFNÁ induce NO synthesis and stimulate transport of arginine up to severalfold [Simmons and Murphy, 1992;Schmidlin and Wiesinger, 1995]. Therefore, the effect of preincubation of the astroglia-rich primary cultures with immunostimulants was investigated.…”

Section: Resultsmentioning

confidence: 99%

“…However, an intracellular NO/citrulline cycle within astroglial cells should not be ruled out. In contrast to up-regulation of glial arginine synthesis [Heneka et al, 1999;Schmidlin and Wiesinger, 1998] and arginine transport [Schmidlin et al, 1995] by immunostimulants, uptake of citrulline by glial cells does not respond to compounds such as LPS or IFNÁ, strong inductors of NO synthesis.…”

Section: Discussionmentioning

confidence: 96%

Transport of <i>L</i>-Citrulline in Neural Cell Cultures

Schmidlin

Fischer²,

Wiesinger³

2000

Dev Neurosci

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Uptake of L-[¹⁴C]citrulline was studied in cell culture models of the main neural cell populations, in astroglia-rich primary cultures derived from neonatal rat brain, in rat glioma cells C6-BU-1, in cells of the murine microglial clone N11 and in the glioma × neuroblastoma hybrid cell line 108CC15 with neuronal properties. For comparison, cells of the peripheral macrophage cell line RAW 264.7 were also investigated. A saturable component of uptake was found in all cases with K_M values between 0.4 and 3.4 mM and V_max values between 15 and 35 nmol· min^–1·(mg protein)^–1. A nonsaturable component dominated uptake at high concentrations of extracellular citrulline. Rates of uptake of L-citrulline were not affected when Na⁺ or Cl^– were omitted from the incubation medium or in the presence of depolarizing concentrations of K⁺. Saturable uptake of citrulline was strongly inhibited by an excess of histidine or β-2-aminobicyclo-(2.2.1)-heptane-2-carboxylic acid; excess amounts of arginine, creatine, glutamate, cysteic acid or N-methyl-α-aminoisobutyric acid did not reduce citrulline uptake. Preincubation of the cells with bacterial lipopolysaccharide and interferon γ did not stimulate transport of citrulline. The results suggest that at physiological concentrations citrulline is taken up by neural cells with the help of transport system L for large neutral amino acids. Therefore, in the brain, effective utilization of extracellular citrulline as part of an intercellular trafficking of intermediates of an NO/citrulline cycle depends on the concentrations of all neutral amino acids present.

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“…In different cells including MΦ and AMΦ it has been observed that stimuli which induce iNOS, i.e. cause an enhanced demand of L-arginine, also increase L-arginine uptake (Bogle et al 1992;Sato et al 1992;Lind et al 1993;Schmidlin and Wiesinger 1995;Mössner et al 1998). …”

Section: Maria Donata Messeri Dreißig · Rainer Hammermann · Jutta Mösmentioning

confidence: 99%

In rat alveolar macrophages lipopolysaccharides exert divergent effects on the transport of the cationic amino acids l -arginine and l -ornithine

Dreißig

Hammermann

Mössner

et al. 2000

Naunyn-Schmiedeberg's Archives of Pharmacology

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In rat alveolar macrophages (AMphi) it was tested whether induction of iNOS by lipopolysaccharides (LPS) is accompanied by changes in L-arginine transport and whether L-ornithine, the product of arginase released from AMphi, could, via inhibition of L-arginine uptake, act as a paracrine inhibitor of NO synthesis. Rat AMphi (cultured for 20 h in the absence or presence of 1 microg/ml LPS) were incubated in Krebs-HEPES solution containing [3H]-L-arginine (0.1 microM for 2 min or 100 microM for 5 min) and the cellular radioactivity was determined as a measure of L-arginine uptake. In parallel, cells were incubated for 6 h in Krebs-HEPES solution containing 0-1 mM L-arginine and nitrite accumulation was determined. [3H]-L-arginine uptake (0.1 microM or 100 microM) occurred independently of sodium ions and was inhibited by L-ornithine (EC50: 117 and 562 microM, respectively) and with similar potencies by L-lysine. In LPS-treated AMphi the concentration inhibition curve of L-ornithine was shifted to the right by about a factor of 4, whereas that of L-lysine was only marginally shifted to the right. L-Leucine (0.1 and 1 mM) inhibited [3H]-L-arginine (0.1 microM) by 43 and 58%, respectively, and the effect of 0.1 mM L-leucine was partially sodium dependent. In LPS-treated AMphi, 0.1 mM L-leucine no longer inhibited [3H]-L-arginine and the effect of 1 mM L-leucine was attenuated. Kinetic analysis of the transport of [3H]-L-arginine and [14C]-L-ornithine revealed two components for each amino acid with Km values of 21 and 114 microM (L-arginine) and 39 and 1050 microM (L-ornithine), respectively. After LPS treatment Km2 of L-arginine transport was reduced to 63 microM and Vmax of both components was increased, whereas Km2 of L-ornithine transport was enhanced to 1392 microM and Vmax1 reduced. LPS-stimulated AMphi, incubated in amino acid-free Krebs-HEPES solution, produced about 4 nmol nitrite/10(6) cells per 6 h, and L-arginine enhanced nitrite accumulation maximally about threefold (EC50: 30 microM). L-ornithine, up to 3 mM, failed to affect significantly nitrite accumulation observed in the presence of 30 or 100 microM L-arginine. Rat AMphi express mRNA for two cationic amino acid transporters (CAT-1 and CAT-2B), and LPS markedly up-regulated mRNA for CAT-2B in parallel with mRNA for iNOS, but had no effect on that for CAT-1. In conclusion, in rat AMphi LPS up-regulates L-arginine transport and induces changes in the characteristics of the cationic amino acid transport resulting in preferential transport of L-arginine. These effects may be regarded as cellular measures to ensure a high L-arginine supply for iNOS.

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Stimulation of Arginine Transport and Nitric Oxide Production by Lipopolysaccharide Is Mediated by Different Signaling Pathways in Astrocytes

Cited by 40 publications

References 16 publications

Peroxynitrite Stimulates l-Arginine Transport Systemy+ in Glial Cells

Peroxynitrite Stimulates l-Arginine Transport Systemy+ in Glial Cells

Transport of <i>L</i>-Citrulline in Neural Cell Cultures

In rat alveolar macrophages lipopolysaccharides exert divergent effects on the transport of the cationic amino acids l -arginine and l -ornithine

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