Vasoactive Intestinal Peptide induces glucose and neutral amino acid uptake through mTOR signalling in human cytotrophoblast cells

AbstractThe transport of nutrients across the placenta involves trophoblast cell specific transporters modulated through the mammalian target of rapamycin (mTOR). The vasoactive intestinal peptide (VIP) has embryotrophic effects in mice and regulates human cytotrophoblast cell migration and invasion. Here we explored the effect of VIP on glucose and System A amino acid uptake by human trophoblast-derived cells (Swan 71 and BeWo cell lines). VIP activated D-glucose specific uptake in single cytotrophoblast cells in a concentration-dependent manner through PKA, MAPK, PI3K and mTOR signalling pathways. Glucose uptake was reduced in VIP-knocked down cytotrophoblast cells. Also, VIP stimulated System A amino acid uptake and the expression of GLUT1 glucose transporter and SNAT1 neutral amino acid transporter. VIP increased mTOR expression and mTOR/S6 phosphorylation whereas VIP silencing reduced mTOR mRNA and protein expression. Inhibition of mTOR signalling with rapamycin reduced the expression of endogenous VIP and of VIP-induced S6 phosphorylation. Our findings support a role of VIP in the transport of glucose and neutral amino acids in cytotrophoblast cells through mTOR-regulated pathways and they are instrumental for understanding the physiological regulation of nutrient sensing by endogenous VIP at the maternal-foetal interface.

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Vasoactive Intestinal Peptide induces glucose and neutral amino acid uptake through mTOR pathways in human trophoblast cells

Placenta ◽

10.1016/j.placenta.2019.06.198 ◽

2019 ◽

Vol 83 ◽

pp. e60-e61

Author(s):

Fatima Merech ◽

Elizabeth Soczewski ◽

Vanesa Hauk ◽

Daniel Paparini ◽

Rosanna Ramhorst ◽

...

Keyword(s):

Amino Acid ◽

Vasoactive Intestinal Peptide ◽

Amino Acid Uptake ◽

Neutral Amino Acid ◽

Acid Uptake ◽

Trophoblast Cells ◽

Human Trophoblast ◽

Human Trophoblast Cells

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Neutral amino acid influx in developing rabbit blastocysts

AJP Cell Physiology ◽

10.1152/ajpcell.1986.251.2.c285 ◽

1986 ◽

Vol 251 (2) ◽

pp. C285-C292 ◽

Cited By ~ 7

Author(s):

J. E. Bell ◽

K. E. Begg ◽

Y. Sin ◽

J. D. Biggers ◽

D. J. Benos

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Amino Acid Uptake ◽

Neutral Amino Acid ◽

Acid Uptake ◽

Amino Acid Analogue ◽

Independent Components ◽

System A ◽

Acid Analogue ◽

System L

The influx of the neutral amino acids glycine, aminoisobutyric acid (AIB), and leucine into rabbit blastocysts was measured. In day 6 postcoitus (pc) embryos, glycine influx was Na+ independent, whereas AIB and leucine influx involved both Na+-dependent and independent components. From days 5 to 7 pc, the leucine and AIB influx remained constant, although the Na+-dependent fraction decreased and the Na+-independent fraction increased with age. None of the Na+-independent influx was inhibited by methylaminoisobutyric acid (MeAIB), an amino acid analogue specific for the system A of neutral amino acid uptake. In addition, MeAIB influx was Na+ independent, implying that system A is not involved in leucine or AIB uptake. All Na+-dependent influx is thus considered to occur via system ASC. System L contributed only to the influx of leucine at days 6 and 7 pc, as measured by inhibition of Na+-independent influx by 2-amino-bicyclo-(2,2,1)-heptane-2-carboxylic acid.

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Energization of amino acid uptake by system A in cultured human fibroblasts

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)52335-8 ◽

1991 ◽

Vol 266 (3) ◽

pp. 1591-1596

Author(s):

V Dall'Asta ◽

O Bussolati ◽

G G Guidotti ◽

G C Gazzola

Keyword(s):

Amino Acid ◽

Human Fibroblasts ◽

Amino Acid Uptake ◽

Acid Uptake ◽

System A ◽

Cultured Human Fibroblasts

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Seasonal variation in glucose and neutral amino acid uptake in the estuarine crab Neohelice granulata

Comparative Biochemistry and Physiology Part A Molecular & Integrative Physiology ◽

10.1016/j.cbpa.2009.02.033 ◽

2009 ◽

Vol 153 (3) ◽

pp. 252-257 ◽

Cited By ~ 8

Author(s):

Sandra Costa Valle ◽

Paula Eichler ◽

José Eduardo Maciel ◽

Gabriel Machado ◽

Luiz Carlos Kucharski ◽

...

Keyword(s):

Seasonal Variation ◽

Amino Acid ◽

Amino Acid Uptake ◽

Neutral Amino Acid ◽

Acid Uptake ◽

Neohelice Granulata

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Anionic amino acid uptake by microvillous membrane vesicles from human placenta

AJP Cell Physiology ◽

10.1152/ajpcell.1989.257.5.c1005 ◽

1989 ◽

Vol 257 (5) ◽

pp. C1005-C1011 ◽

Cited By ~ 91

Author(s):

A. J. Moe ◽

C. H. Smith

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Glutamate Uptake ◽

Membrane Vesicles ◽

Amino Acid Uptake ◽

Maternal Blood ◽

Acid Uptake ◽

Dependent Manner ◽

Concentration Dependent Manner

The transport mechanisms for anionic amino acids in trophoblast microvillous (maternal facing) membrane were investigated by characterization of L-[3H]aspartate and L-[3H]glutamate uptake in membrane vesicles. Uptake of the anionic amino acids was by a single high-affinity Na+-dependent K+-stimulated cotransporter that is pH sensitive and electrogenic. A second Na+-dependent transporter could not be discriminated, and there was no observable Na+-independent uptake. An outwardly directed K+ gradient (100 mM KCl inside) resulted in a 5- to 10-fold stimulation in glutamate uptake in the presence of Na+. Intravesicular KCl had no effect on transporter affinity but increased transporter velocity in a concentration-dependent manner. Inhibition of Na+-K+-dependent uptake of L-aspartate and L-glutamate (20 mM, 30 s) by 2 mM unlabeled amino acids demonstrated stereoselectivity for L-glutamate but not for L-aspartate. The neutral amino acids (L-alanine, L-threonine, L-serine, L-cysteine, L-phenylalanine) were not effective inhibitors. These data are consistent with an anionic amino acid transporter in the microvillous membrane of the trophoblast, which has characteristics qualitatively similar to the X-AG system found in other epithelia. This system may mediate the concentrative placental uptake of anionic amino acids from maternal blood in utero.

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Insulin Signaling and Its Regulation of System A Amino Acid Uptake in Cultured Rat Vascular Smooth Muscle Cells

Circulation Research ◽

10.1161/01.res.79.6.1167 ◽

1996 ◽

Vol 79 (6) ◽

pp. 1167-1176 ◽

Cited By ~ 27

Author(s):

Toshiyuki Obata ◽

Atsunori Kashiwagi ◽

Hiroshi Maegawa ◽

Yoshihiko Nishio ◽

Satoshi Ugi ◽

...

Keyword(s):

Smooth Muscle ◽

Amino Acid ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Vascular Smooth Muscle Cells ◽

Insulin Signaling ◽

Muscle Cells ◽

Amino Acid Uptake ◽

Acid Uptake ◽

System A

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Effects of phenylarsine oxide on insulin-stimulated system A amino acid uptake in skeletal muscle

AJP Cell Physiology ◽

10.1152/ajpcell.1991.261.4.c608 ◽

1991 ◽

Vol 261 (4) ◽

pp. C608-C613 ◽

Cited By ~ 26

Author(s):

E. J. Henriksen

Keyword(s):

Skeletal Muscle ◽

Amino Acid ◽

Amino Acid Uptake ◽

Isobutyric Acid ◽

Acid Uptake ◽

Mammalian Skeletal Muscle ◽

Phenylarsine Oxide ◽

System A ◽

Carrier Molecule ◽

20 Nm

The role of vicinal sulfhydryls in the stimulation by insulin of system A amino acid uptake in mammalian skeletal muscle was investigated. Neutral amino acid uptake via system A carriers was assessed using the nonmetabolizable analogue alpha-(methylamino)isobutyric acid (MeAIB). Phenylarsine oxide (PAO), a trivalent arsenical that interacts with vicinal sulfhydryls, at 40 microM inhibited basal and insulin-stimulated (2 mU/ml) MeAIB uptake in rat epitrochlearis muscles by approximately 50% and approximately 80%, respectively. No significant changes in the ATP level or in the lactate-to-pyruvate ratio were observed. Both inhibitory effects were completely preventable by coincubation with dimercaptopropanol, a vicinal dithiol, indicating the effects were mediated specifically by interactions with vicinal sulfhydryls. Stimulation of MeAIB uptake by the insulin-mimicker vanadate (10 mM) or by insulin-like growth factor I (IGF-I, 20 nM) was also inhibited by 80-90% by PAO. Kinetic analysis showed that PAO decreased the apparent Vmax for basal and insulin-stimulated MeAIB uptake without altering the apparent Km. MeAIB uptake already maximally stimulated by insulin was rapidly (half-time = approximately 10 min) reversed by the addition of PAO so that the rate of MeAIB uptake was the same as in muscles incubated throughout with insulin and PAO. These results implicate a major role for vicinal sulfhydryls in the stimulation by insulin of amino acid uptake via system A carriers in skeletal muscle and suggest that the site of action of PAO on this system is distal to the insulin receptor, possibly at the carrier molecule itself.

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