Transport of &lt;i&gt;L&lt;/i&gt;-Citrulline in Neural Cell Cultures

Schmidlin, Andreas; Fischer, Susanne; Wiesinger, Heinrich

doi:10.1159/000017468

Cited by 22 publications

(15 citation statements)

References 34 publications

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“…There are sodium-independent transporters in the nervous system (26) and sodium-dependent transporters in rat endothelial cells (33). In the kidney, Mitsuoka et al (19) identified B(0)AT1 and b(0,ϩ)AT, sodiumindependent and -dependent transporters of citrulline on the apical membrane of cultured rat renal proximal tubular cells.…”

Section: Discussionmentioning

confidence: 99%

In vivo renal arginine release is impaired throughout development of chronic kidney disease

Chen¹,

Baylis

2010

American Journal of Physiology-Renal Physiology

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The kidney is a major site of arginine synthesis where citrulline is converted to arginine via argininosuccinate synthase (ASS) and lyase (ASL). The rate-limiting step in arginine synthesis by the normal kidney is the rate of citrulline delivery and uptake to the renal cortex. We tested whether with chronic kidney disease (CKD) renal arginine synthesis may be compromised. Using the 5/6 renal ablation/infarction (A/I) injury model, we measured renal citrulline delivery and uptake as well as arginine release at early, moderate, and severe stages of CKD vs. healthy controls. The renal plasma flow (RPF) and arterial-renal venous difference was measured at baseline and during citrulline infusion. Citrulline delivery was reduced at all stages of disease due to marked reductions in RPF and despite moderately increased plasma citrulline. Early after 5/6 A/I, the kidney demonstrated a compensatory increase in citrulline uptake while at moderate and severe injury baseline citrulline uptake fell. At all stages of CKD, renal arginine release was markedly reduced. Citrulline infusion increased plasma citrulline in all groups, resulting in increased renal delivery vs. baseline. In healthy kidneys and early injury, citrulline uptake increased with the infusion, but only in the normal kidney did arginine production increase in parallel with the increased citrulline uptake. At moderate and severe injury, there was no increase in citrulline uptake or arginine production. The fall in arginine production in 5/6 A/I was due to an early loss of ASS and ASL conversion of citrulline, which combined with a later reduction in citrulline uptake.

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Section: Discussionmentioning

confidence: 99%

In vivo renal arginine release is impaired throughout development of chronic kidney disease

Chen¹,

Baylis

2010

American Journal of Physiology-Renal Physiology

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“…Neutral amino acids such as L -citrulline are transported through cell membranes by several distinct transport systems in different cell types, including macrophages [14], rat aortic smooth muscle cells [15], neural cells [16], bovine aortic endothelial cells [17], and intestinal cells [2]. Systems B 0 and B 0,+ , as Na + -dependent transport systems for neutral amino acids, have been identified [18].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of L-citrulline transport through blood-brain barrier in the brain capillary endothelial cell line (TR-BBB cells)

Lee

Kang

2017

J Biomed Sci

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Background L-Citrulline is a neutral amino acid and a major precursor of L-arginine in the nitric oxide (NO) cycle. Recently it has been reported that L-citrulline prevents neuronal cell death and protects cerebrovascular injury, therefore, L-citrulline may have a neuroprotective effect to improve cerebrovascular dysfunction. Therefore, we aimed to clarify the brain transport mechanism of L-citrulline through blood-brain barrier (BBB) using the conditionally immortalized rat brain capillary endothelial cell line (TR-BBB cells), as an in vitro model of the BBB.MethodsThe uptake study of [14C] L-citrulline, quantitative real-time polymerase chain reaction (PCR) analysis, and rLAT1, system b0,+, and CAT1 small interfering RNA study were performed in TR-BBB cells.ResultsThe uptake of [14C] L-citrulline was a time-dependent, but ion-independent manner in TR-BBB cells. The transport process involved two saturable components with a Michaelis–Menten constant of 30.9 ± 1.0 μM (Km1) and 1.69 ± 0.43 mM (Km2). The uptake of [14C] L-citrulline in TR-BBB cells was significantly inhibited by neutral and cationic amino acids, but not by anionic amino acids. In addition, [14C]L-citrulline uptake in the cells was markedly inhibited by 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH), which is the inhibitor of the large neutral amino acid transporter 1 (LAT1), B0, B0,+ and harmaline, the inhibitor of system b0,+. Gabapentin and L-dopa as the substrates of LAT1 competitively inhibited the uptake of [14C] L-citrulline. IC50 values for L-dopa, gabapentin, L-phenylalanine and L-arginine were 501 μM, 223 μM, 68.9 μM and 33.4 mM, respectively. The expression of mRNA for LAT1 was predominantly increased 187-fold in comparison with that of system b0,+ in TR-BBB cells. In the studies of LAT1, system b0,+ and CAT1 knockdown via siRNA transfection into TR-BBB cells, the transcript level of LAT1 and [14C] L-citrulline uptake by LAT1 siRNA were significantly reduced compared with those by control siRNA in TR-BBB cells.ConclusionsOur results suggest that transport of L-citrulline is mainly mediated by LAT1 in TR-BBB cells. Delivery strategy for LAT1-mediated transport and supply of L-citrulline to the brain may serve as therapeutic approaches to improve its neuroprotective effect in patients with cerebrovascular disease.

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“…In some NOS-containing cells, the intracellular concentration of L-arginine can be well above the K m of NOS. Several mechanisms have been proposed to explain this arginine paradox: the co-localization of arginine transporters and NOS, the intracellular regeneration of arginine from citrulline, a balance between arginase and NOS activity, and the regulation of transport-system mRNA levels by NO concentration (Schmidlin et al 2000;Rasmusen et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Phe-met-arg-phe (FMRF)-amide is a substrate source of NO synthase in the gastropod nervous system

et al. 2006

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The possible involvement of the L-arginine-containing Phe-met-arg-phe (FMRF)-amide (FMRFa) in neuronal nitric oxide (NO) biosynthesis was studied in a gastropod species. We found NADPH-diaphorase-positive neurons and FMRFa-containing fibers in close proximity in the enteric nervous system. Administration of L-arginine and FMRFa induced quantitatively similar nitrite production in both intact intestinal tissues and tissue homogenates. These changes could be prevented by the presence of NOARG (an NO synthase inhibitor). Neither chemically modified FMRFa (D-arginine instead of L-arginine) nor amino acid constituents of FMRFa (methionine, phenylalanine) affected basal nitrite production. FMRFa-induced alterations were reduced in the presence of Na+ channel blockers (tetrodotoxin, amiloride, lidocaine), the Na+/K+ATPase inhibitor ouabain, or protease inhibitors (leupeptine, pepstatine-a). FMRFa and its amino acid constituents were analyzed by paper chromatography. When FMRFa was added to tissue homogenates, the peptide was eliminated within 1-2 min, whereas methionine, phenylalanine, arginine, and citrulline levels were elevated simultaneously. We tested the effects of FMRFa, L-arginine, and NOARG on intestinal contractile activity. FMRFa relaxed the intestine for 1-2 min and then induced contractions for 20-40 min. In the presence of NOARG, no relaxant effect of FMRFa was recorded. As administration of L-arginine strongly inhibits the mechanical activity of the intestinal muscle, NO production presumably plays a substantial role in the action of FMRFa, at least in the initial phase. Our biochemical data indicate a direct involvement of FMRFa in NO biosynthesis. FMRFa might be hydrolyzed by extracellular peptidases and then the locally released arginine might be transported into the cells and broken-down to produce NO. Depolarization-induced NO production attributable to the activation of amiloride-sensitive Na+ channels might also be involved.

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

Cited by 22 publications

References 34 publications

In vivo renal arginine release is impaired throughout development of chronic kidney disease

In vivo renal arginine release is impaired throughout development of chronic kidney disease

Characteristics of L-citrulline transport through blood-brain barrier in the brain capillary endothelial cell line (TR-BBB cells)

Phe-met-arg-phe (FMRF)-amide is a substrate source of NO synthase in the gastropod nervous system

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