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Leung SWS, Shi Y. The glycolytic process in endothelial cells and its implications. Acta Pharmacol Sin 2022; 43:251-259. [PMID: 33850277 PMCID: PMC8791959 DOI: 10.1038/s41401-021-00647-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 02/22/2021] [Indexed: 02/06/2023] Open
Abstract
Endothelial cells play an obligatory role in regulating local vascular tone and maintaining homeostasis in vascular biology. Cell metabolism, converting food to energy in organisms, is the primary self-sustaining mechanism for cell proliferation and reproduction, structure maintenance, and fight-or-flight responses to stimuli. Four major metabolic processes take place in the energy-producing process, including glycolysis, oxidative phosphorylation, glutamine metabolism, and fatty acid oxidation. Among them, glycolysis is the primary energy-producing mechanism in endothelial cells. The present review focused on glycolysis in endothelial cells under both physiological and pathological conditions. Since the switches among metabolic processes precede the functional changes and disease developments, some prophylactic and/or therapeutic strategies concerning the role of glycolysis in cardiovascular disease are discussed.
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Affiliation(s)
- Susan, Wai Sum Leung
- grid.194645.b0000000121742757Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Yi Shi
- grid.8547.e0000 0001 0125 2443Institute of Clinical Science, Zhongshan Hospital, Fudan University, Shanghai, 200032 China ,grid.8547.e0000 0001 0125 2443Key Laboratory of Organ Transplantation, Zhongshan Hospital, Fudan University, Shanghai, 200032 China
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Mateus I, Feijó M, Espínola LM, Vaz CV, Correia S, Socorro S. Glucose and glutamine handling in the Sertoli cells of transgenic rats overexpressing regucalcin: plasticity towards lactate production. Sci Rep 2018; 8:10321. [PMID: 29985416 PMCID: PMC6037673 DOI: 10.1038/s41598-018-28668-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 06/22/2018] [Indexed: 12/13/2022] Open
Abstract
Sertoli cells (SCs) possess the unparalleled ability to provide the germ line with growth factors and nutrients. Although SCs can oxidize amino acids, e.g., glutamine, they mostly metabolize glucose, producing high amounts of lactate, the germ cells preferential substrate. Regucalcin (RGN) is a calcium-binding protein that has been indicated as a regulator of cell metabolism. In this study, we investigated glucose and glutamine handling in the SCs of transgenic rats overexpressing RGN (Tg-RGN) comparatively with wild-type (Wt) littermates. Primary SCs isolated from adult Tg-RGN animals and maintained in culture for 24 hours, produced and exported more lactate, despite consuming less glucose. These observations were underpinned by increased expression of alanine transaminase, and augmented glutamine consumption, suggesting that alternative routes are contributing to the enhanced lactate production in the SCs of Tg-RGN rats. Moreover, lactate seems to be used by germ cells, with diminished apoptosis being detected in the seminiferous tubules of Tg-RGN animals cultured ex vivo. The obtained results showed a distinct metabolism in the SCs of Wt and Tg-RGN rats widening the roles assigned to RGN in spermatogenesis. These findings also highlighted the plasticity of SCs metabolism, a feature that would be exploited in the context of male infertility.
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Affiliation(s)
- Inês Mateus
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Mariana Feijó
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Luís M Espínola
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Cátia V Vaz
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Sara Correia
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Sílvia Socorro
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal.
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3
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Heo YT, Ha WT, Lee R, Lee WY, Jeong HY, Hwang KC, Song H. Mammary alveolar cell as in vitro evaluation system for casein gene expression involved in glucose level. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2016; 30:878-885. [PMID: 27660020 PMCID: PMC5411853 DOI: 10.5713/ajas.16.0515] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/08/2016] [Accepted: 09/19/2016] [Indexed: 01/09/2023]
Abstract
Objective Glucose is an essential fuel in the energy metabolism and synthesis pathways of all mammalian cells. In lactating animals, glucose is the major precursor for lactose and is a substrate for the synthesis of milk proteins and fat in mammary secretory (alveolar) epithelial cells. However, clear utilization of glucose in mammary cells during lactogenesis is still unknown, due to the lack of in vitro analyzing models. Therefore, the objective of this study was to test the reliability of the mammary alveolar (MAC-T) cell as an in vitro study model for glucose metabolism and lactating system. Methods Undifferentiated MAC-T cells were cultured in three types of Dulbecco’s modified Eagle’s medium with varying levels of glucose (no-glucose: 0 g/L, low-glucose: 1 g/L, and high-glucose: 4.5 g/L) for 8 d, after which differentiation to casein secretion was induced. Cell proliferation and expression levels of apoptotic genes, Insulin like growth factor-1 (IGF1) receptor, oxytocin receptor, αS1, αS2, and β casein genes were analyzed at 1, 2, 4, and 8 d after differentiation. Results The proliferation of MAC-T cells with high-glucose treatment was seen to be significantly higher. Expression of apoptotic genes was not affected in any group. However, expression levels of the mammary development related gene (IGF1 receptor) and lactation related gene (oxytocin receptor) were significantly higher in the low-glucose group. Expressions of αS1-casein, αS2-casein, and β-casein were also higher in the low-glucose treated group as compared to that in the no-glucose and high-glucose groups. Conclusion The results demonstrated that although a high-glucose environment increases cell proliferation in MAC-T cells, a low-glucose treatment to MAC-T cells induces higher expression of casein genes. Our results suggest that the MAC-T cells may be used as an in vitro model to analyze mammary cell development and lactation connected with precise biological effects.
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Affiliation(s)
- Young Tae Heo
- Department of Stem Cell and Regenerative Biology, College of Animal Bioscience and Technology, Konkuk University, Seoul 143-701, Korea
| | - Woo Tae Ha
- Department of Stem Cell and Regenerative Biology, College of Animal Bioscience and Technology, Konkuk University, Seoul 143-701, Korea
| | - Ran Lee
- Department of Stem Cell and Regenerative Biology, College of Animal Bioscience and Technology, Konkuk University, Seoul 143-701, Korea
| | - Won-Young Lee
- Division of Food Bioscience, RIBHS, College of Biomedical and Health Sciences, Konkuk University, Chung-ju 380-701, Korea
| | - Ha Yeon Jeong
- Department of Animal Resources Development Dairy Science Division, National Institute of Animal Science, RDA, Cheonan 331-801, Korea
| | - Kyu Chan Hwang
- Sooam Biotech Research Foundations, Seoul 152-895, Korea
| | - Hyuk Song
- Department of Stem Cell and Regenerative Biology, College of Animal Bioscience and Technology, Konkuk University, Seoul 143-701, Korea
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Chehtane M, Khaled AR. Interleukin-7 mediates glucose utilization in lymphocytes through transcriptional regulation of the hexokinase II gene. Am J Physiol Cell Physiol 2010; 298:C1560-71. [PMID: 20200205 DOI: 10.1152/ajpcell.00506.2009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The cytokine interleukin-7 (IL-7) has essential growth activities that maintain the homeostatic balance of the immune system. Little is known of the mechanism by which IL-7 signaling regulates metabolic activity in support of its vital function in lymphocytes. We observed that IL-7 deprivation caused a rapid decline in the metabolism of glucose that was attributable to loss of intracellular glucose retention. To identify the transducer of the IL-7 metabolic signal, we examined the expression of three important regulators of glucose metabolism, the glucose transporter GLUT-1 and two glycolytic enzymes, hexokinase II (HXKII) and phosphofructokinase-1 (PFK-1), using an IL-7-dependent T-cell line and primary lymphocytes. We found that in lymphocytes deprived of IL-7 loss of glucose uptake correlated with decreased expression of HXKII. Readdition of IL-7 to cytokine-deprived lymphocytes restored the transcription of the HXKII gene within 2 h, but not that of GLUT-1 or PFK-1. IL-7-mediated increases in HXKII, but not GLUT-1 or PFK-1, were also observed at the protein level. Inhibition of HXKII with 3-bromopyruvate or specific small-interfering RNA decreased glucose utilization, as well as ATP levels, in the presence of IL-7, whereas overexpression of HXKII, but not GLUT-1, restored glucose retention and increased ATP levels in the absence of IL-7. We conclude that IL-7 controls glucose utilization by regulating the gene expression of HXKII, suggesting a mechanism by which IL-7 supports bioenergetics that control cell fate decisions in lymphocytes.
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Affiliation(s)
- Mounir Chehtane
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL 32827, USA
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Sweet IR, Gilbert M, Maloney E, Hockenbery DM, Schwartz MW, Kim F. Endothelial inflammation induced by excess glucose is associated with cytosolic glucose 6-phosphate but not increased mitochondrial respiration. Diabetologia 2009; 52:921-31. [PMID: 19219423 PMCID: PMC2741088 DOI: 10.1007/s00125-009-1272-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 01/08/2009] [Indexed: 10/21/2022]
Abstract
AIMS/HYPOTHESIS Exposure of endothelial cells to high glucose levels suppresses responses to insulin, including induction of endothelial nitric oxide synthase activity, through pro-inflammatory signalling via the inhibitor of nuclear factor kappaB (IkappaB)alpha-nuclear factor kappaB (NF-kappaB) pathway. In the current study, we aimed to identify metabolic responses to glucose excess that mediate endothelial cell inflammation and insulin resistance. Since endothelial cells decrease their oxygen consumption rate (OCR) in response to glucose, we hypothesised that increased mitochondrial function would not mediate these cells' response to excess substrate. METHODS The effects of glycolytic and mitochondrial fuels on metabolic intermediates and end-products of glycolytic and oxidative metabolism, including glucose 6-phosphate (G6P), lactate, CO(2), NAD(P)H and OCR, were measured in cultured human microvascular endothelial cells and correlated with IkappaBalpha phosphorylation. RESULTS In response to increases in glucose concentration from low to physiological levels (0-5 mmol/l), production of G6P, lactate, NAD(P)H and CO(2) each increased as expected, while OCR was sharply reduced. IkappaBalpha activation was detected at glucose concentrations >5 mmol/l, which was associated with parallel increases of G6P levels, whereas downstream metabolic pathways were insensitive to excess substrate. CONCLUSIONS/INTERPRETATION Phosphorylation of IkappaBalpha by excess glucose correlates with increased levels of the glycolytic intermediate G6P, but not with lactate generation or OCR, which are inhibited well below saturation levels at physiological glucose concentrations. These findings suggest that oxidative stress due to increased mitochondrial respiration is unlikely to mediate endothelial inflammation induced by excess glucose and suggests instead the involvement of G6P accumulation in the adverse effects of hyperglycaemia on endothelial cells.
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Affiliation(s)
- I R Sweet
- Department of Medicine, Diabetes and Obesity Center of Excellence, University of Washington at South Lake Union, Seattle, Washington 98195-8055, USA.
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Farrar RS, Battiprolu PK, Pierson NS, Rodnick KJ. Steroid-induced cardiac contractility requires exogenous glucose, glycolysis and the sarcoplasmic reticulum in rainbow trout. ACTA ACUST UNITED AC 2006; 209:2114-28. [PMID: 16709913 DOI: 10.1242/jeb.02241] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recent data from our laboratory suggest that sex steroids promote contractile function in cardiac muscle of rainbow trout (Oncorhynchus mykiss Walbaum), and there are sex differences in hormone signaling and cardiac function. The current study investigated whether steroid-induced inotropism in electrically paced (0.5 Hz, 14 degrees C) ventricle strips at 90% Lmax (1) has a metabolic requirement for exogenous glucose and (2) is associated with enhanced intracellular Ca2+ storage and release from the sarcoplasmic reticulum (SR). We also explored whether sex differences exist in extracellular Ca2+ (Ca2+o) or cardiac sensitivity to Ca2+o. In the absence or at low concentrations (1 or 2 mmol l-)) of exogenous glucose, resting tension and relaxation time were increased selectively in cardiac tissue from females. Increasing glucose promoted twitch force in a bell-shaped manner, with 5 mmol l-1 representing the optimal concentration for both sexes. The positive inotropic effects of physiological concentrations of testosterone (T) and 17beta-estradiol (E2) in male and female trout ventricle strips, respectively, developed slowly (10-45 min) and were not apparent in glucose-free medium, in medium containing iodoacetate (IAA), an inhibitor of glycolysis, or medium containing 5 mmol l-) lactate or pyruvate. Male ventricle strips had increased inotropic responses to glucose and T compared with female strips exposed to glucose and E2. Furthermore, sexually maturing males showed a greater inotropic response than immature males or females. Pretreatment with ryanodine (a specific blocker of SR Ca2+ release) also eliminated the inotropic effects of sex steroids and exogenous glucose and reduced the post-rest potentiation of contractile force (a marker of SR Ca2+ storage). By contrast, the inotropic effects of epinephrine (Epi) or elevated Ca2+o were faster (developing within 1-3 min) and were not diminished by the presence or absence of glucose or by pretreatment with IAA or ryanodine. Sex differences were also found in responsiveness to caffeine (males>females) and the relationship between Ca2+ concentration and force development above baseline. The Ca2+50 was lower in female cardiac tissue than males, suggesting greater Ca2+ sensitivity, and although plasma albumin was higher in females, total and ionized plasma Ca2+ did not differ between the sexes. For the first time, our study highlights the importance of extracellular glucose, glycolytic activity and SR Ca2+ storage and release for sex steroid-induced inotropism in the trout ventricle. Conversely, the inotropes Epi and elevated [Ca2+o] do not require the presence or metabolism of exogenous glucose or the SR for signaling their positive effects on contractility. These results also demonstrate novel sex-related differences in cardiac reliance on exogenous glucose, Ca2+ sensitivity and SR function and thus should be considered in future studies.
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Affiliation(s)
- Richard S Farrar
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209-8007, USA
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Qutub AA, Hunt CA. Glucose transport to the brain: a systems model. ACTA ACUST UNITED AC 2005; 49:595-617. [PMID: 16269321 DOI: 10.1016/j.brainresrev.2005.03.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Revised: 03/02/2005] [Accepted: 03/09/2005] [Indexed: 02/07/2023]
Abstract
Glucose transport to the brain involves sophisticated interactions of solutes, transporters, enzymes, and cell signaling processes, within an intricate spatial architecture. The dynamics of the transport are influenced by the adaptive nature of the blood-brain barrier (BBB), the semi-impermeable membranes of brain capillaries. As both the gate and the gatekeeper between blood-borne nutrients and brain tissue, the BBB helps govern brain homeostasis. Glucose in the blood must cross the BBB's luminal and abluminal membranes to reach neural tissue. A robust representation of the glucose transport mechanism can highlight a target for brain therapeutic intervention, help characterize mechanisms behind several disease phenotypes, or suggest a new delivery route for drugs. The challenge for researchers is understanding the relationships between influential physiological variables in vivo, and using that knowledge to predict how alterations or interventions affect glucose transport. This paper reviews factors influencing glucose transport and approaches to representing blood-to-brain glucose transport including in vitro, in vivo, and kinetic models. Applications for different models are highlighted, while their limitations in answering arising questions about the human in vivo BBB lead to a discussion of an alternate approach. A developing complex systems simulation is introduced, initiating a single platform to represent the dynamics of glucose transport across the adapting human blood-brain barrier.
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Affiliation(s)
- Amina A Qutub
- Joint Graduate Group in Bioengineering, University of California, Berkeley and San Francisco, USA.
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Gaudreault N, Scriven DRL, Moore EDW. Characterisation of glucose transporters in the intact coronary artery endothelium in rats: GLUT-2 upregulated by long-term hyperglycaemia. Diabetologia 2004; 47:2081-92. [PMID: 15662550 DOI: 10.1007/s00125-004-1583-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2004] [Accepted: 07/18/2004] [Indexed: 01/22/2023]
Abstract
AIMS/HYPOTHESIS We have examined the effects of streptozotocin-induced type 1 diabetes on the expression and subcellular distribution of the classic sugar transporters (GLUT-1 to 5 and sodium-dependent glucose transporter-1 [SGLT-1]) in the endothelial cells of an en face preparation of septal coronary artery from Wistar rats. METHODS The presence of the GLUT isoforms and SGLT-1 in the endothelial cell layer was determined by immunohistochemistry using wide-field fluorescence microscopy coupled to deconvolution, and was quantified by digital image analysis. RESULTS We found that all of the transporters were expressed within these cells and that all except SGLT-1 were preferentially located on the abluminal side. The heaviest labelling was adjacent to the cell-to-cell junctions where the luminal and abluminal membranes are in close proximity, which may reflect a spatial organisation specialised for vectorial glucose transport across the thinnest part of the cytoplasm. Long-term hyperglycaemia, induced by streptozotocin, significantly downregulated GLUT-1, 3, 4 and 5 and dramatically upregulated GLUT-2, leaving SGLT-1 unchanged. CONCLUSIONS/INTERPRETATION We conclude that the high susceptibility of endothelial cells to glucose toxicity may be the result of the subcellular organisation of their GLUTs and the increased expression of GLUT-2.
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Affiliation(s)
- N Gaudreault
- Department of Physiology, University of British Columbia, 2146 Health Sciences Mall, Vancouver, B.C., V6T 1Z3, Canada
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Taubert D, Rosenkranz A, Berkels R, Roesen R, Schömig E. Acute effects of glucose and insulin on vascular endothelium. Diabetologia 2004; 47:2059-71. [PMID: 15662548 DOI: 10.1007/s00125-004-1586-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Accepted: 07/22/2004] [Indexed: 10/26/2022]
Abstract
AIMS/HYPOTHESIS Chronic exposure to high concentrations of glucose has consistently been demonstrated to impair endothelium-dependent, nitric oxide (NO)-mediated vasodilation. In contrast, several clinical investigations have reported that acute exposure to high glucose, alone or in combination with insulin, triggers vasodilation. The aim of this study was to examine whether elevated glucose itself stimulates endothelial NO formation or enhances insulin-mediated endothelial NO release. METHODS We measured NO release and vessel tone ex vivo in porcine coronary conduit arteries (PCAs). Intracellular Ca(2+) was monitored in porcine aortic endothelial cells (PAECs) by fura-2 fluorescence. Expression of the Na(+)/glucose cotransporter-1 (SGLT-1) was assayed in PAECs and PCA endothelium by RT-PCR. RESULTS Stimulation of PCAs with D: -glucose, but not the osmotic control L: -glucose, induced a transient increase in NO release (EC(50) approximately 10 mmol/l), mediated by a rise in intracellular Ca(2+) levels due to an influx from the extracellular space. This effect was abolished by inhibitors of the plasmalemmal Na(+)/Ca(2+) exchanger (dichlorobenzamil) and the SGLT-1 (phlorizin), which was found to be expressed in aortic and coronary endothelium. Alone, D: -glucose did not relax PCA, but did augment the effect of insulin on NO release and vasodilation. CONCLUSIONS/INTERPRETATION An increased supply of extracellular D: -glucose appears to enhance the activity of the endothelial isoform of nitric oxide synthase by increasing intracellular Na(+) concentrations via SGLT-1, which in turn stimulates an extracellular Ca(2+) influx through the Na(+)/Ca(2+) exchanger. This mechanism may be responsible for glucose-enhanced, insulin-dependent increases in tissue perfusion (including coronary blood-flow), thus accelerating glucose extraction from the blood circulation to limit the adverse vascular effects of prolonged hyperglycaemia.
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Affiliation(s)
- D Taubert
- Department of Pharmacology, Medical Hospital of the University of Cologne, Gleueler Str. 24, 50931, Cologne, Germany.
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10
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Korcok J, Dixon SJ, Lo TCY, Wilson JX. Differential effects of glucose on dehydroascorbic acid transport and intracellular ascorbate accumulation in astrocytes and skeletal myocytes. Brain Res 2003; 993:201-7. [PMID: 14642847 DOI: 10.1016/j.brainres.2003.09.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Skeletal muscle and brain are major sites of glucose transport and ascorbate (vitamin C) storage. Ascorbate is oxidized to dehydroascorbic acid (DHAA) when used as an enzyme cofactor or free radical scavenger. We evaluated the hypothesis that glucose regulates DHAA uptake and reduction to ascorbate (i.e., recycling) by skeletal muscle cells and cerebral astrocytes. DHAA uptake was inhibited partially by glucose added simultaneously with DHAA. Comparison of wild type L6 skeletal muscle cells with an L6-derived cell line (D23) deficient in facilitative hexose transporter isoform 3 (GLUT3), indicated that both GLUT3 and facilitative hexose transporter isoform 1 (GLUT1) mediate DHAA uptake. Preincubation of muscle cells with glucose inhibited the rates of glucose and DHAA uptake, and decreased the intracellular concentration of ascorbate derived from recycling of DHAA. In contrast, glucose preincubation did not depress GLUT1 protein and activity levels or DHAA recycling in astrocytes. These results establish that glucose downregulates subsequent recycling of DHAA by skeletal muscle cells but not astrocytes.
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Affiliation(s)
- Jasminka Korcok
- Department of Physiology and Pharmacology, Faculty of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada N6A 5C1
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Mann GE, Yudilevich DL, Sobrevia L. Regulation of amino acid and glucose transporters in endothelial and smooth muscle cells. Physiol Rev 2003; 83:183-252. [PMID: 12506130 DOI: 10.1152/physrev.00022.2002] [Citation(s) in RCA: 319] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
While transport processes for amino acids and glucose have long been known to be expressed in the luminal and abluminal membranes of the endothelium comprising the blood-brain and blood-retinal barriers, it is only within the last decades that endothelial and smooth muscle cells derived from peripheral vascular beds have been recognized to rapidly transport and metabolize these nutrients. This review focuses principally on the mechanisms regulating amino acid and glucose transporters in vascular endothelial cells, although we also summarize recent advances in the understanding of the mechanisms controlling membrane transport activity and expression in vascular smooth muscle cells. We compare the specificity, ionic dependence, and kinetic properties of amino acid and glucose transport systems identified in endothelial cells derived from cerebral, retinal, and peripheral vascular beds and review the regulation of transport by vasoactive agonists, nitric oxide (NO), substrate deprivation, hypoxia, hyperglycemia, diabetes, insulin, steroid hormones, and development. In view of the importance of NO as a modulator of vascular tone under basal conditions and in disease and chronic inflammation, we critically review the evidence that transport of L-arginine and glucose in endothelial and smooth muscle cells is modulated by bacterial endotoxin, proinflammatory cytokines, and atherogenic lipids. The recent colocalization of the cationic amino acid transporter CAT-1 (system y(+)), nitric oxide synthase (eNOS), and caveolin-1 in endothelial plasmalemmal caveolae provides a novel mechanism for the regulation of NO production by L-arginine delivery and circulating hormones such insulin and 17beta-estradiol.
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Affiliation(s)
- Giovanni E Mann
- Centre for Cardiovascular Biology and Medicine, Guy's, King's, and St. Thomas' School of Biomedical Sciences, King's College London, London, United Kingdom.
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Suda K, Rothen-Rutishauser B, Günthert M, Wunderli-Allenspach H. Phenotypic characterization of human umbilical vein endothelial (ECV304) and urinary carcinoma (T24) cells: endothelial versus epithelial features. In Vitro Cell Dev Biol Anim 2001; 37:505-14. [PMID: 11669284 DOI: 10.1290/1071-2690(2001)037<0505:pcohuv>2.0.co;2] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
ECV304 cells reported as originating from human umbilical vein endothelial cells by spontaneous transformation have been used as a model cell line for endothelia over the last decade. Recently, deoxyribonucleic acid fingerprinting revealed an identical genotype for ECV304 and T24 cells (urinary bladder carcinoma cell line). In order to resolve the apparent discrepancy between the identical genotype and the fact that ECV304 cells phenotypically show important endothelial characteristics, a comparative study was performed. Immortalized porcine brain microvascular endothelial cells/C1-2, and Madin Darby canine kidney cells were included as typical endothelial and epithelial cells, respectively. Various methods, such as confocal laser scanning microscopy. Western blot, and protein activity tests, were used to study the cell lines. ECV304 and T24 cells differ in criteria, such as growth behavior, cytoarchitecture, tight junction arrangement. transmembrane electrical resistance, and activity of gamma-glutamyltransferase. Several endothelial markers (von Willebrand factor, uptake of low-density lipoprotein, vimentin) could clearly be identified in ECV304, but not in T24 cells. Desmoglein and cytokeratin, both known as epithelial markers, were found in ECV304 as well as in T24 tells. However, differences were found for the two cell lines with respect to the type of cytokeratin: in ECV304 cells mainly cytokeratin 18 (45 kDa) is found, whereas in T24 cells cytokeratin 8 (52 kDa) is predominant. As we could demonstrate, the ECV304 cell line exposes many endothelial features which, in view of the scarcity of suitable endothelial cell lines, still make it an attractive in vitro model for endothelia.
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Affiliation(s)
- K Suda
- Department of Applied BioSciences, ETH Zurich, Switzerland
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Beckman JA, Goldfine AB, Gordon MB, Creager MA. Ascorbate restores endothelium-dependent vasodilation impaired by acute hyperglycemia in humans. Circulation 2001; 103:1618-23. [PMID: 11273987 DOI: 10.1161/01.cir.103.12.1618] [Citation(s) in RCA: 233] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Endothelium-dependent vasodilation is impaired in patients with insulin-dependent and non-insulin-dependent diabetes mellitus and restored by vitamin C administration, implicating a causative role for oxidant stress. Hyperglycemia per se attenuates endothelium-dependent vasodilation in healthy subjects. Accordingly, this study investigated whether impaired endothelium-dependent vasodilation caused by hyperglycemia in nondiabetic humans is restored by administration of the antioxidant vitamin C. METHODS AND RESULTS Endothelium-dependent vasodilation was measured by incremental brachial artery administration of methacholine chloride (0.3 to 10 microg/min) during euglycemia, after 6 hours of hyperglycemia (300 mg/dL) created by dextrose (50%) intra-arterial infusion, and with coadministration of vitamin C (24 mg/min) during hyperglycemia. Endothelium-dependent vasodilation was significantly diminished by hyperglycemia (P:=0.02 by ANOVA) and restored by vitamin C (P:=0.04). In contrast, endothelium-dependent vasodilation was not affected by equimolar infusions of mannitol, with and without vitamin C coinfusion (P:=NS). Endothelium-independent vasodilation was measured by incremental infusion of verapamil chloride (10 to 300 microg/min) without and with coadministration of N:(G)-monomethyl-L-arginine (L-NMMA). In the absence of L-NMMA, endothelium-independent vasodilation was not significantly altered during hyperglycemia (P:=NS) but was augmented by vitamin C (P:=0.04). The coadministration of L-NMMA eliminated the vitamin C-related augmentation in verapamil-mediated vasodilation. CONCLUSIONS Vitamin C administration restores endothelium-dependent vasodilation impaired by acute hyperglycemia in healthy humans in vivo. These findings suggest that hyperglycemia may contribute in part to impaired vascular function through production of superoxide anion.
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Affiliation(s)
- J A Beckman
- Cardiovascular Division, Brigham and Women's Hospital, Boston, MA 02115, USA
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Braun A, Hämmerle S, Suda K, Rothen-Rutishauser B, Günthert M, Krämer SD, Wunderli-Allenspach H. Cell cultures as tools in biopharmacy. Eur J Pharm Sci 2000; 11 Suppl 2:S51-60. [PMID: 11033427 DOI: 10.1016/s0928-0987(00)00164-0] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A survey is given on a few selected cell culture models that are used for transport studies. They are characterised for growth, transcellular electrical resistance and cytoarchitecture. The importance of standardisation in view of their use as transport models is documented. Their potential for studies on passive permeation and P-glycoprotein-mediated transport is explored and related to published data. Transport studies are presented that were performed in a two-chamber set-up, the Costar "vertical diffusion system". A series of non-homologous compounds showed similar permeability data (P(app)) in the different cell cultures. The origin of the cell type had no remarkable influence on passive transcellular permeation. MDCK cells, an epithelial cell line of canine kidney origin, are perfectly suited to screen for passive permeation. They have low expression of transporter proteins and low metabolic activity. In general, they probably represent the best-known epithelial cell line with respect to genetics as well as lipid and protein composition. MDCK cells are easy to handle. Transport experiments can be done between 7 and 14 days after seeding, when the stationary growth phase is reached. To screen for P-glycoprotein substrates, efflux and uptake studies were performed with mdr1-transfected MDCK cells (MDR1-MDCK) in a one-chamber system in the presence or absence of verapamil or cyclosporin A as inhibitor. Evidence is presented why the transfected cells, which express large amounts of P-glycoprotein, are not suitable for two-chamber transport studies.
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Affiliation(s)
- A Braun
- Biopharmacy, Department of Applied BioSciences, Federal Institute of Technology ETH, CH-8057, Zurich, Switzerland
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