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Ghneim HK, Alfhili MA, Alharbi SO, Alhusayni SM, Abudawood M, Aljaser FS, Al-Sheikh YA. Comprehensive investigations of key mitochondrial metabolic changes in senescent human fibroblasts. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2022; 26:263-275. [PMID: 35766004 PMCID: PMC9247707 DOI: 10.4196/kjpp.2022.26.4.263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 03/23/2022] [Accepted: 04/07/2022] [Indexed: 06/15/2023]
Abstract
There is a paucity of detailed data related to the effect of senescence on the mitochondrial antioxidant capacity and redox state of senescent human cells. Activities of TCA cycle enzymes, respiratory chain complexes, hydrogen peroxide (H2O2), superoxide anions (SA), lipid peroxides (LPO), protein carbonyl content (PCC), thioredoxin reductase 2 (TrxR2), superoxide dismutase 2 (SOD2), glutathione peroxidase 1 (GPx1), glutathione reductase (GR), reduced glutathione (GSH), and oxidized glutathione (GSSG), along with levels of nicotinamide cofactors and ATP content were measured in young and senescent human foreskin fibroblasts. Primary and senescent cultures were biochemically identified by monitoring the augmented cellular activities of key glycolytic enzymes including phosphofructokinase, lactate dehydrogenase, and glycogen phosphorylase, and accumulation of H2O2, SA, LPO, PCC, and GSSG. Citrate synthase, aconitase, α-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, isocitrate dehydrogenase, and complex I-III, IIIII, and IV activities were significantly diminished in P25 and P35 cells compared to P5 cells. This was accompanied by significant accumulation of mitochondrial H2O2, SA, LPO, and PCC, along with increased transcriptional and enzymatic activities of TrxR2, SOD2, GPx1, and GR. Notably, the GSH/GSSG ratio was significantly reduced whereas NAD+/NADH and NADP+/NADPH ratios were significantly elevated. Metabolic exhaustion was also evident in senescent cells underscored by the severely diminished ATP/ADP ratio. Profound oxidative stress may contribute, at least in part, to senescence pointing at a potential protective role of antioxidants in aging-associated disease.
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Affiliation(s)
- Hazem K. Ghneim
- Chair of Medical and Molecular Genetics Research, Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 12372, Saudi Arabia
| | - Mohammad A. Alfhili
- Chair of Medical and Molecular Genetics Research, Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 12372, Saudi Arabia
| | - Sami O. Alharbi
- Chair of Medical and Molecular Genetics Research, Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 12372, Saudi Arabia
| | - Shady M. Alhusayni
- Chair of Medical and Molecular Genetics Research, Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 12372, Saudi Arabia
| | - Manal Abudawood
- Chair of Medical and Molecular Genetics Research, Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 12372, Saudi Arabia
| | - Feda S. Aljaser
- Chair of Medical and Molecular Genetics Research, Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 12372, Saudi Arabia
| | - Yazeed A. Al-Sheikh
- Chair of Medical and Molecular Genetics Research, Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Saud University, Riyadh 12372, Saudi Arabia
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2
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de Kok MJC, Schaapherder AF, Wüst RCI, Zuiderwijk M, Bakker JA, Lindeman JHN, Le Dévédec SE. Circumventing the Crabtree effect in cell culture: A systematic review. Mitochondrion 2021; 59:83-95. [PMID: 33812964 DOI: 10.1016/j.mito.2021.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/08/2021] [Accepted: 03/29/2021] [Indexed: 10/21/2022]
Abstract
Metabolic reprogramming and mitochondrial dysfunction are central elements in a broad variety of physiological and pathological processes. While cell culture established itself as a versatile technique for the elaboration of physiology and disease, studying metabolism using standard cell culture protocols is profoundly interfered by the Crabtree effect. This phenomenon refers to the adaptation of cultured cells to a glycolytic phenotype, away from oxidative phosphorylation in glucose-containing medium, and questions the applicability of cell culture in certain fields of research. In this systematic review we aim to provide a comprehensive overview and critical appraisal of strategies reported to circumvent the Crabtree effect.
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Affiliation(s)
- Michèle J C de Kok
- Department of Surgery and Leiden Transplant Center, Leiden University Medical Center, Leiden, The Netherlands
| | - Alexander F Schaapherder
- Department of Surgery and Leiden Transplant Center, Leiden University Medical Center, Leiden, The Netherlands
| | - Rob C I Wüst
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Melissa Zuiderwijk
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Jaap A Bakker
- Department of Clinical Chemistry & Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Jan H N Lindeman
- Department of Surgery and Leiden Transplant Center, Leiden University Medical Center, Leiden, The Netherlands
| | - Sylvia E Le Dévédec
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands.
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Shi L, Zhao C, Wang H, Lei T, Liu S, Cao J, Lu Z. Dimethylarginine Dimethylaminohydrolase 1 Deficiency Induces the Epithelial to Mesenchymal Transition in Renal Proximal Tubular Epithelial Cells and Exacerbates Kidney Damage in Aged and Diabetic Mice. Antioxid Redox Signal 2017; 27:1347-1360. [PMID: 28594240 DOI: 10.1089/ars.2017.7022] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
AIMS Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, is mainly degraded by dimethylarginine dimethylaminohydrolase (DDAH). Emerging evidence suggests that plasma ADMA accumulation and DDAH1 activity/expression reduction are linked to chronic kidney disease (CKD) pathology, but the mechanisms remain largely unknown. Here, we examined the role of ADMA/DDAH1 in the epithelial-mesenchymal transition (EMT) of tubular epithelial cells (TECs), an important mechanism for the pathogenesis of renal fibrosis. RESULTS In HK-2 cells, DDAH1 expression was reduced by aldosterone treatment, and overexpression of DDAH1 significantly attenuated aldosterone-induced EMT. More interestingly, DDAH1 deficiency resulted in EMT-related changes in primary TECs via increasing oxidative stress, impairing adenosine monophosphate-activated kinase (AMPK) signaling, and downregulating of peroxiredoxin 5 (Prdx5). However, those effects could not be mimicked by increasing the ADMA concentration. After regular feeding for 24 months or inducing type 2 diabetes, Ddah1-/- mice had higher serum creatinine levels than wild-type (WT) mice. In the kidneys of the aged or diabetic mice, loss of DDAH1 resulted in more interstitial fibrosis, more collagen deposition, and greater induction of EMT-related changes and oxidative stress than in the WT kidneys. Innovation and Conclusion: Our results provide the first direct evidence that the DDAH1 has a marked effect on kidney fibrosis and oxidative stress induced by aging or diabetes. Our findings suggest that strategies to increase DDAH1 activity in TECs may provide a novel approach to attenuate CKD development. Antioxid. Redox Signal. 27, 1347-1360.
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Affiliation(s)
- Linlin Shi
- College of Life Science, University of Chinese Academy of Sciences , Beijing, China
| | - Chenyang Zhao
- College of Life Science, University of Chinese Academy of Sciences , Beijing, China
| | - Hongyun Wang
- College of Life Science, University of Chinese Academy of Sciences , Beijing, China
| | - Tong Lei
- College of Life Science, University of Chinese Academy of Sciences , Beijing, China
| | - Shasha Liu
- College of Life Science, University of Chinese Academy of Sciences , Beijing, China
| | - Jianwei Cao
- College of Life Science, University of Chinese Academy of Sciences , Beijing, China
| | - Zhongbing Lu
- College of Life Science, University of Chinese Academy of Sciences , Beijing, China
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4
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Egr-1 deficiency protects from renal inflammation and fibrosis. J Mol Med (Berl) 2016; 94:933-42. [DOI: 10.1007/s00109-016-1403-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 02/04/2016] [Accepted: 02/29/2016] [Indexed: 10/22/2022]
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5
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Chen WC, Lin HH, Tang MJ. Regulation of proximal tubular cell differentiation and proliferation in primary culture by matrix stiffness and ECM components. Am J Physiol Renal Physiol 2014; 307:F695-707. [PMID: 25056346 DOI: 10.1152/ajprenal.00684.2013] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
To explore whether matrix stiffness affects cell differentiation, proliferation, and transforming growth factor (TGF)-β1-induced epithelial-mesenchymal transition (EMT) in primary cultures of mouse proximal tubular epithelial cells (mPTECs), we used a soft matrix made from monomeric collagen type I-coated polyacrylamide gel or matrigel (MG). Both kinds of soft matrix benefited primary mPTECs to retain tubular-like morphology with differentiation and growth arrest and to evade TGF-β1-induced EMT. However, the potent effect of MG on mPTEC differentiation was suppressed by glutaraldehyde-induced cross-linking and subsequently stiffening MG or by an increasing ratio of collagen in the soft mixed gel. Culture media supplemented with MG also helped mPTECs to retain tubular-like morphology and a differentiated phenotype on stiff culture dishes as soft MG did. We further found that the protein level and activity of ERK were scaled with the matrix stiffness. U-0126, a MEK inhibitor, abolished the stiff matrix-induced dedifferentiation and proliferation. These data suggest that the ERK signaling pathway plays a vital role in matrix stiffness-regulated cell growth and differentiation. Taken together, both compliant property and specific MG signals from the matrix are required for the regulation of epithelial differentiation and proliferation. This study provides a basic understanding of how physical and chemical cues derived from the extracellular matrix regulate the physiological function of proximal tubules and the pathological development of renal fibrosis.
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Affiliation(s)
- Wan-Chun Chen
- Institute of Basic Medical Sciences, National Cheng-Kung University Medical College, Tainan, Taiwan; and
| | - Hsi-Hui Lin
- Department of Physiology, National Cheng-Kung University Medical College, Tainan, Taiwan
| | - Ming-Jer Tang
- Institute of Basic Medical Sciences, National Cheng-Kung University Medical College, Tainan, Taiwan; and Department of Physiology, National Cheng-Kung University Medical College, Tainan, Taiwan
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6
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Chang SH, Chiang IN, Chen YH, Young TH. Serum-free culture of rat proximal tubule cells with enhanced function on chitosan. Acta Biomater 2013; 9:8942-51. [PMID: 23816651 DOI: 10.1016/j.actbio.2013.06.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 05/01/2013] [Accepted: 06/20/2013] [Indexed: 12/19/2022]
Abstract
The proximal tubule performs a variety of important renal functions and is the major site for nutrient reabsorption. The purpose of this study is to culture rat renal proximal tubule cells (PTCs) on chitosan without serum to maintain a transcellular pathway to transport water and ions effectively without loss of highly differentiated cell function. The effect of chitosan, which is structurally similar to glycosaminoglycans, in the absence of serum on the primary cultured PTCs was compared that of collagen with or without serum. Two days after seeding, more tubule fragments and higher PTC viability were observed on chitosan than on collagen with or without serum. Proliferation marker Ki-67 immunostaining and phosphorylated extracellular-regulated kinase (ERK) expression results displayed similar proliferation capability of PTCs established on chitosan without serum and collagen with 2% fetal bovine serum after 4 days of incubation. When grown to confluence, PTCs formed a monolayer with well-organized tight junctions and formation of domes on chitosan without serum. Moreover, evaluation of the transepithelial electrical resistance showed that both chitosan and serum were involved in the modification of water and ion transport in confluent cells. By showing the direct suppression of PTC growth and dome formation treated with heparinase, we demonstrated that the interaction between cell surface heparin sulfate proteoglycan and chitosan played an important role in PTC proliferation and differentiation. A successful primary culture of PTCs has now been produced on chitosan in serum-free culture condition, which offers potential applications for chitosan in renal tissue engineering.
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7
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A 3-D organoid kidney culture model engineered for high-throughput nephrotoxicity assays. Biomaterials 2012; 33:4700-11. [DOI: 10.1016/j.biomaterials.2012.02.063] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Accepted: 02/29/2012] [Indexed: 01/17/2023]
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8
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Biju MP, Akai Y, Shrimanker N, Haase VH. Protection of HIF-1-deficient primary renal tubular epithelial cells from hypoxia-induced cell death is glucose dependent. Am J Physiol Renal Physiol 2005; 289:F1217-26. [PMID: 16048903 DOI: 10.1152/ajprenal.00233.2005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ischemic acute renal failure is a frequent clinical problem in hospitalized patients and is associated with significant mortality. Hypoxia-inducible factor 1 (HIF-1) mediates cellular adaptation to hypoxia by regulating biological processes important for cell survival, which include glycolysis, angiogenesis, erythropoiesis, apoptosis, and proliferation. To investigate the role of HIF-1 in hypoxia-induced renal epithelial cell death, we generated mice that allow inactivation of HIF-1α by tetracycline-inducible Cre-loxP-mediated recombination in primary renal proximal tubule cells (PRPTC), resulting in a suppression of HIF-1-mediated gene transcription during oxygen deprivation. In the absence of glucose, the onset and the degree of hypoxia-induced cell death in HIF-1-deficient PRPTC were comparable to wild-type cells. However, when glucose availability was limited, the onset of cell death was delayed in either PRPTC that were HIF-1 deficient or in wild-type PRPTC when glycolysis or glucose uptake was partially inhibited. Our findings suggest in an in vitro genetic model that 1) the generation of adequate energy levels for the maintenance of PRPTC viability under hypoxia does not require HIF-1 and 2) that HIF-1 regulates the timing of hypoxia-induced cell death and apoptosis onset through its effects on glucose consumption.
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Affiliation(s)
- Mangatt P Biju
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, 19104-6144, USA
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9
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Bolon C, Gauthier C, Simonnet H. Glycolysis inhibition by palmitate in renal cells cultured in a two-chamber system. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:C1732-8. [PMID: 9374661 DOI: 10.1152/ajpcell.1997.273.5.c1732] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A major shortcoming of renal proximal tubular cells (RPTC) in culture is the gradual modification of their energy metabolism from the oxidative type to the glycolytic type. To test the possible reduction of glycolysis by naturally occurring long-chain fatty acids, RPTC were cultured in a two-chamber system, with albumin-bound palmitate (0.4 mM) added to the basolateral chamber after confluency. Twenty-four hours of contact with palmitate decreased glycolysis by 38% provided that carnitine was present; lactate production was decreased by 38%, and the decrease in glycolysis resulted from a similar decrease of basolateral and apical net uptake of glucose. In contrast to the previously described effect of the nonphysiological oxidative substrate heptanoate, palmitate promoted a long-term decrease in lactate production and sustained excellent cellular growth. After 4 days of contact, decreased glycolysis was maintained even in the absence of carnitine and resulted from a decrease of basolateral uptake only, suggestive of long-term regulation different from the earlier effects. Thus, although cultured RPTC lost their oxidative phenotype, they exhibited a type of regulation (Randle effect) that is found in the oxidative-type but not in the glycolytic-type tissues, therefore unmasking a regulative capacity barely detectable in fresh RPTC. Low PO2 (50 mmHg in the apical chamber) could be a major cause of elevated glycolysis and could hinder the effects of palmitate.
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Affiliation(s)
- C Bolon
- Laboratoire de Physiopathologie Métabolique et Rénale, Institut National de la Santé et de la Recherche Médicale, Faculté de Médecine Alexis Carrel, Université Lyon I, France
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10
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Stio M, Lunghi B, Celli A, Nassi P, Treves C. Effect of 1,25-dihydroxyvitamin D3 on proliferation in senescent IMR-90 human fibroblasts. Mech Ageing Dev 1996; 91:23-36. [PMID: 8910257 DOI: 10.1016/0047-6374(96)01761-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The response of IMR-90 human fetal lung fibroblasts at high population doubling level (PDL > 42) to 1,25-dihydroxyvitamin D3[1,25(OH)2D3] was investigated to clarify whether some metabolic and molecular parameters of senescent cells are affected by the hormone treatment. Pyruvate kinase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase activity significantly increased after treatment of confluent-phase cells with 10 nM 1,25(OH)2D3 for 24 h. Steroid specificity was established by the failure of 10 nM levels of 25-hydroxyvitamin D3 to affect the enzyme activities, while estradiol-17 beta and progesterone produced a slight increase in glucose-6-phosphate dehydrogenase and lactate dehydrogenase levels, respectively. 1,25(OH)2D3 also affected fibroblast proliferation, protein content/cell and DNA synthesis. The cell number significantly decreased after a 48 h incubation with 1,25(OH)2D3 at various concentrations (0.01-1 nM) when compared with control fibroblasts, while an increase in the protein content/cell was demonstrated. The same experiment, carried out by protracting the incubation with the hormone for 72 h, showed a similar trend, but 10 nM 1,25(OH)2D3 was also able to inhibit cell proliferation and to stimulate protein synthesis. The incorporation of [3H]thymidine into DNA increased after the treatment of high PDL fibroblasts with 0.01-1 nM of hormone for 48 h in comparison with controls.
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Affiliation(s)
- M Stio
- Department of Biochemical Sciences, University of Florence, Italy
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11
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Lunghi B, Meacci E, Stio M, Celli A, Bruni P, Nassi P, Treves C. 1,25-dihydroxyvitamin D3 inhibits proliferation of IMR-90 human fibroblasts and stimulates pyruvate kinase activity in confluent-phase cells. Mol Cell Endocrinol 1995; 115:141-8. [PMID: 8824889 DOI: 10.1016/0303-7207(95)03681-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This study tested the hypothesis that 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) plays a role in regulating some aspects of metabolism in IMR-90 normal human fetal lung fibroblasts. Among the enzymes studied, only pyruvate kinase showed a significant increase after treatment of confluent-phase cells with 1,25(OH)2D3 at various concentrations (0.1-100 nM range) for 24 h. A parallel increase in lactate output was observed. Steroid specificity was established by the failure of 10 nM levels of 25-hydroxyvitamin D3, estradiol-17 beta and progesterone to affect pyruvate kinase activity. The determination of the time course of [3H]-2-deoxy-D-glucose transport indicated that the hormone did not influence the transmembrane transport system of D-glucose. The addition of the inhibitors cycloheximide and actinomycin D to the culture medium abolished, at least in part, the 1,25(OH)2D3 stimulation of pyruvate kinase activity, suggesting the probable dependence of the hormone effect on cellular RNA and protein synthesis. 1,25(OH)2D3 also affected fibroblast growth and DNA synthesis. Cell number significantly decreased after 2-5 days treatment with 10 nM hormone in comparison with control fibroblasts, and also the incorporation of [3H]thymidine into DNA decreased after treatment of the cells with 1 and 10 nM hormone for 48 h. In conclusion, these data demonstrate that 1,25(OH)2D3 stimulates pyruvate kinase activity in confluent-phase IMR-90 human fibroblasts by a mechanism probably dependent on de novo protein synthesis, and also affects cell growth and DNA synthesis in sub-confluent-phase cells.
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Affiliation(s)
- B Lunghi
- Department of Biochemical Sciences of the University of Florence, Italy
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12
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Monteil C, Fillastre JP, Morin JP. Expression and subcellular distribution of phosphoenolpyruvate carboxykinase in primary cultures of rabbit kidney proximal tubule cells: comparative study with renal and hepatic PEPCK in vivo. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1243:437-45. [PMID: 7727519 DOI: 10.1016/0304-4165(94)00171-s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The behaviour of the phosphoenolpyruvate carboxykinase (PEPCK) in rabbit proximal tubule cells in primary culture was investigated and compared with renal and hepatic PEPCK in vivo. The enzyme activity decreased rapidly in rabbit proximal tubule cells developed in hormonally defined medium supplemented with glucose and insulin. In this condition, the cytosolic form disappears with time. Without glucose and insulin, the subcellular location of PEPCK is similar to the location observed in proximal tubule freshly isolated and in renal cortex, with approx. 50% of mitochondrial form and approx. 50% of cytosolic form. However, the levels of mRNA that encode the cytosolic PEPCK are not detectable in cell cultures, whatever the medium composition. Treatment with dibutyryl cAMP caused a 14-fold induction of PEPCK mRNA in 6 h. This result indicates that the transcription of cytosolic PEPCK can be induced in cell cultures. Lactate or pyruvate additions did not modify the levels of PEPCK mRNA whereas specific activity increased rapidly, suggesting an activation of an inactive form in cell cultures. Moreover, lactate induced increased specific activity of the sole mitochondrial form while pyruvate induced increased specific activities of both mitochondrial and cytosolic form. Thus, subcellular location of PEPCK in rabbit proximal tubule cells appears to be modulated by the available substrate in culture medium. This observation parallels the changes observed in vivo since a modification of subcellular location of this enzyme was seen between fed and fasted rabbit, when subcellular distribution remains similar between fed and starved rats. Moreover, in the fasted liver of rabbit, a decrease of the mitochondrial PEPCK specific activity is seen concomitant with an increase in cytosolic PEPCK activity. These results point out the relative contributions of the cytosolic and mitochondrial PEPCK to rabbit gluconeogenesis.
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Affiliation(s)
- C Monteil
- INSERM U-295-Université de Rouen, Saint Etienne du Rouvray, France
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13
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Griner RD, Schnellmann RG. Decreasing glycolysis increases sensitivity to mitochondrial inhibition in primary cultures of renal proximal tubule cells. In Vitro Cell Dev Biol Anim 1994; 30A:30-4. [PMID: 8193771 DOI: 10.1007/bf02631415] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have previously shown that shaking the culture plates (SHAKE) of rabbit renal proximal tubule cells (RPTC) to maintain adequate aeration increased aerobic metabolism and decreased the induction of glycolysis compared to RPTC cultured under standard conditions (STILL). However, glycolysis in SHAKE RPTC remained elevated compared to glycolysis in proximal tubules in vivo. In the present study the contribution of culture medium sugar composition and concentration to glycolytic metabolism was assessed in RPTC. SHAKE and STILL RPTC cultured in 5 mM glucose contained lactate levels equivalent to the respective SHAKE and STILL RPTC cultured in standard culture medium which contains 17.5 mM glucose. Similarly, the activity of lactate dehydrogenase was unchanged by lowering the medium glucose concentration. Substituting 5 mM galactose for 5 mM glucose in the culture medium significantly reduced the lactate content of both SHAKE and STILL RPTC but had no effect on lactate dehydrogenase activity. Cell growth was equivalent under all culture conditions. Sensitivity to mitochondrial inhibition was determined for each culture condition by measuring cell death after exposure to the respiratory inhibitor antimycin A. The results showed a hierarchy of sensitivity to antimycin A (5 mM galactose SHAKE > 5 mM glucose SHAKE > 17.5 mM glucose SHAKE = 17.5 mM glucose STILL), which was generally inversely correlated with the level of glycolysis as measured by lactate content (17.5 mM glucose STILL > 17.5 mM glucose SHAKE = 5 mM glucose SHAKE > 5 mM galactose SHAKE).
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Affiliation(s)
- R D Griner
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens 30602
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14
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Griner RD, Aleo MD, Schnellmann RG. The role of short chain fatty acid substrates in aerobic and glycolytic metabolism in primary cultures of renal proximal tubule cells. In Vitro Cell Dev Biol Anim 1993; 29A:649-55. [PMID: 8376317 DOI: 10.1007/bf02634554] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This study examined the role of odd and even short-chain fatty acid substrates on aerobic and glycolytic metabolism in well-aerated primary cultures of rabbit renal proximal tubule cells (RPTC). Increasing oxygen delivery to primary cultures of RPTC by shaking the dishes (SHAKE) reduced total lactate levels and lactate dehydrogenase (LDH) activity and reduced net glucose consumption compared to RPTC cultured under standard conditions (STILL). The addition of butyrate, valerate, heptanoate, or octanoate to SHAKE RPTC produced variable effects on glycolytic metabolism. Although butyrate and heptanoate further reduced total lactate levels and net glucose consumption during short-term culture (< 24 h), no fatty acid tested further reduced total lactate levels, net glucose consumption, or LDH activity during long-term culture (7 days). During the first 12 h of culture, maintenance of aerobic metabolism in SHAKE RPTC was dependent on medium supplementation with fatty acid substrates (2 mM). However, by 24 h, SHAKE RPTC did not require fatty acid substrates to maintain levels of aerobic metabolism equivalent to freshly isolated proximal tubules and greater than STILL RPTC. This suggests that SHAKE RPTC undergo adaptive changes between 12 and 24 h of culture, which give RPTC the ability to utilize other substrates for mitochondrial oxidation, therefore allowing greater expression of mitochondrial oxidative potential in SHAKE RPTC than in STILL RPTC.
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Affiliation(s)
- R D Griner
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens 30602
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15
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Courjault F, Chevalier J, Leroy D, Toutain H. Effect of glucose and insulin deprivation on differentiation and carbohydrate metabolism of rabbit proximal tubular cells in primary culture. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1177:147-59. [PMID: 8388735 DOI: 10.1016/0167-4889(93)90034-m] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Rabbit proximal tubule cells in primary culture revert from gluconeogenesis to glycolysis. To determine whether glucose and insulin deprivation of the culture medium could prevent this metabolic conversion without a loss of differentiation, rabbit proximal tubule cells were cultured in hormonally defined medium free of glucose and insulin and compared to rabbit proximal tubule cells cultured in medium supplemented with 17.5 mM glucose and 5 micrograms/ml insulin. In the two culture conditions, RPT cells grew at a similar rate and reached confluency within 4-5 days. Patterns of enzyme activity, including brush-border hydrolases, N-acetyl-beta-D-glucosaminidase and glutathione-S-transferases as a function of culture time were comparable in the two media. During the growth phase in glucose- and insulin-free medium, cells showed higher sodium-dependent glucose uptake. Scanning electron microscopy revealed a high density of microvilli at confluency regardless of the culture conditions. In both the presence and absence of glucose and insulin, the activities of gluconeogenic enzymes, phosphoenolpyruvate carboxykinase and fructose-1,6-bisphosphatase, as well as basal and pyruvate-stimulated glucose production fell markedly as a function of time. By contrast, glucose and insulin deprivation greatly reduced both the lactate production rate and the activities of glycolytic enzymes, pyruvate kinase, hexokinase and lactate dehydrogenase.
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Affiliation(s)
- F Courjault
- Département Sécurité du Médicament, Rhône-Poulenc Rorer S.A., Vitry sur Seine, France
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Sango K, Horie H, Sotelo JR, Takenaka T. A high glucose environment improves survival of diabetic neurons in culture. Neurosci Lett 1991; 129:277-80. [PMID: 1745409 DOI: 10.1016/0304-3940(91)90480-h] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Dorsal root ganglia neurons from streptozotocin-induced diabetic and normal C57BL mice were cultured in serum-containing and serum-free media. The ratio of dead cells was higher in diabetic neurons than in controls in the early stages of culture. The effect of glucose concentration on survival in the culture medium was also measured for 1 week. Treatment with high glucose concentrations improved the survival of diabetic neurons, which was enhanced by duration of diabetes in the animal. These results indicate that exposure to hyperglycemia in vivo might adapt neurons to a high glucose environment in vitro.
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Affiliation(s)
- K Sango
- Department of Physiology, School of Medicine, Yokohama City University, Japan
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