EP1144647A2 - Procede d'amelioration du metabolisme d'energie primaire de lignees cellulaires de mammiferes - Google Patents

Procede d'amelioration du metabolisme d'energie primaire de lignees cellulaires de mammiferes

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Publication number
EP1144647A2
EP1144647A2 EP00910644A EP00910644A EP1144647A2 EP 1144647 A2 EP1144647 A2 EP 1144647A2 EP 00910644 A EP00910644 A EP 00910644A EP 00910644 A EP00910644 A EP 00910644A EP 1144647 A2 EP1144647 A2 EP 1144647A2
Authority
EP
European Patent Office
Prior art keywords
cells
cell lines
glutamine
glucose
energy metabolism
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00910644A
Other languages
German (de)
English (en)
Inventor
Roland Wagner
Noushin Irani
Manfred Wirth
Joop Van Den Heuvel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Helmholtz Zentrum fuer Infektionsforschung HZI GmbH
Original Assignee
Helmholtz Zentrum fuer Infektionsforschung HZI GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Helmholtz Zentrum fuer Infektionsforschung HZI GmbH filed Critical Helmholtz Zentrum fuer Infektionsforschung HZI GmbH
Publication of EP1144647A2 publication Critical patent/EP1144647A2/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
    • C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
    • C12N9/00—Enzymes; Proenzymes; Compositions thereof; Processes for preparing, activating, inhibiting, separating or purifying enzymes
    • C12N9/93—Ligases (6)

Definitions

  • the invention relates to a method for improving the primary energy metabolism of mammalian cell lines, expression vectors for use in the method and recombinant mammalian cells with improved primary energy metabolism obtainable by the method.
  • glucose and glutamine have a special position among the numerous essential components of the relatively complex nutrient medium. Because unlike bacteria or yeasts, both substrates are necessary as energy suppliers, with glutamine as the main serves the source of cellular energy (ATP) .. The degree of cellular energy supply from glutamine depends on the individual cell line as well as on the presence and concentration of glucose.
  • the primary energy metabolism of mammalian cells thus consists of glucose and glutamine oxidation and encompasses the metabolic pathways of glycolysis, glutaminolysis and the citrate cycle.
  • the simplified overview of these primary metabolic pathways with branches and crucial enzyme functions is given in FIG. 1.
  • Glyeolysis converts between 80% and 97% of the glucose in mammalian cell lines. However, in contrast to insect or primary cells, almost all of the glucose converted in the glycolysis is processed to lactate in transformed mammalian cell lines, and only a very small part (about 0.2 to 5%) of the glucose carbon or the glycolytic intermediates is obtained the energy-supplying citrate cycle.
  • Glutaminolysis does not represent a single, continuous metabolic pathway like glycolysis, but rather forms a network of up to eight, partly interlinked, alternative metabolic routes, on which glutamine can be oxidized to different degrees and which thus lead to different energy yields and product combinations .
  • glutamine A large part of the glutamine is deaminated and introduced into the citrate cycle via the intermediate a-ketoglutarate, where it can be completely oxidized to C0 2 .
  • glutamine can also be partially converted to the amino acids aspartate, alanine or lactate. These can either be secreted into the culture medium or, in the case of aspartate, can be introduced into the citrate cycle via oxaloacetate.
  • the choice of the routes for the complete or only partial oxidation of the glutamine determines the contribution of the glutamine to the energy balance of the cell.
  • Studies on various mammalian cell lines showed that glutamine in the presence of glucose covers 30% to 65% of the cell's energy requirements, possibly even 98%.
  • the lower the glucose concentration in the medium the higher the contribution of glutamine to the energy balance of the mammalian cell.
  • a key by-product of glutamine degradation is ammonium.
  • glutaminolytic metabolic branch can release one or two moles of ammonium per mole of glutamine, which has a growth-inhibiting to toxic effect on the cells.
  • there is a decrease in the intracellular pH value on the other hand high amounts of ammonium lead to changes in the nucleotide and
  • Metabolism engineering in mammalian cell lines Attempts to significantly improve the growth and productivity of cellular systems probably require the radical change in certain substrate flows of energy metabolism. This requires very precise knowledge of key metabolic points.
  • Rees and Hay (1995) cloned the complete bacterial threonine pathway into a mammalian cell line so that this cell line could grow in threonine-free nutrient medium.
  • the cell line was transfected with two vectors, of which the genes for aspartokinase, aspartate semialdehyde dehydrogenase, homoserine dehydrogenase, homoserine kinase and threonine synthase were constitutively expressed.
  • the complete bacterial pathway for threonine from aspartate was cloned into a mammalian cell line, for the cultivation of which the relatively expensive amino acid threonine is no longer necessary.
  • the transfected cell line showed the same growth behavior as the non-transfected control cell line in threonine-containing medium.
  • the 2,6-sialyltransferase can bind N-acetylneuraminic acid to N-acetylgalactosamine residues of the carbohydrate side chains. Only with this change does the EPO possess human-identical properties that can be important for therapeutic use.
  • the inventors Using an approach to metabolic engineering, the inventors have cloned a recombinant rat brain hexokinase gene into BHK cells in order to expand the rate-determining reaction of glycolysis with additional hexokinase activity and to increase the flow of substances and the amount of cell energy in the form of ATP.
  • the hexokinase activity was up to 3 times higher than usual, the glucose consumption increased, the material flow in the glycolysis increased and the intracellular ATP concentration also increased. Glutamine metabolism was also activated. However, the cell growth rate decreased in the cell lines with strong hexokinase activity and high ATP rates. The production rates of the cells for recombinant Protein products, however, rose. A high ATP content does not seem to promote the growth rates of the cells, but possibly their productivity.
  • the object of the invention is therefore to provide a method for improving the primary metabolism of mammalian cell lines.
  • this object is achieved with a method for improving the primary energy metabolism of mammalian cell lines according to claim 1.
  • the invention further relates to expression vectors for use in the method and recombinant mammalian cells obtainable by the method with improved primary energy metabolism compared to the wild type.
  • the recombinant cell lines obtained by the process according to the invention show increased complete glucose oxidation, reduced lactate production, reduced glutamine consumption, higher ATP content and higher oxygen consumption.
  • the recombinant cell lines in batch cultures grow significantly longer than wild-type cell lines and manage longer with the available nutrient resources.
  • the recombinant cell lines can produce much longer with the existing nutrients, so that the total yield of the product increases and the process costs are reduced in comparison to conventional cell lines.
  • Figure 1 is an overview of primary metabolism in mammalian cells.
  • Figure 2a is a schematic representation of common glucose oxidation in mammalian cell lines.
  • FIG. 2b illustrates the strategy according to the invention for metabolism engineering by introducing a cyto-solically expressed pyruvate carboxylase gene (PYC2) from yeast into the cells according to a preferred embodiment of the invention.
  • PYC2 cyto-solically expressed pyruvate carboxylase gene
  • Figure 3 shows the liberation of the 5 'and 3 "region of the PYC2 gene from flanking yeast-specific sequences.
  • FIG. 4 is a schematic drawing of the expression vector pCMVSHE-PYC2 and the selection vector pAG60.
  • pyruvate carboxylase is already well known as an inherited disorder, with patients suffering from severe acidosis leading to premature death.
  • an additional metabolic side path was introduced according to the invention by introducing a cytoplasmic-expressed pyruvate carboxylase (PC).
  • PC cytoplasmic-expressed pyruvate carboxylase
  • pyruvate carboxylase is active in the yeast Saccharomyces cerevisiae, even without the presence of acetyl-CoA (Colowick and Kaplan).
  • This new step now enables the cells to convert pyruvate from glycolysis in the cytoplasm first into oxaloacetate and then with the cytoplasmic malate dehydrogenase already present to malate, which can then be introduced into the mitochondria for further oxidation via a malate-aspartate shuttle ( Fig. 2b).
  • FIG. 2a shows a schematic representation of the usual glucose oxidation in mammalian cell lines.
  • pyruvate In the mitochondria of primary cells, pyruvate is normally deearboxylated to acetyl-CoA by the pyruvate dehydrogenase complex (PDHC) and introduced into the citrate cycle. Little or no PDHC activity is found in mammalian cell lines.
  • PDHC pyruvate dehydrogenase
  • PC Pyruvate carboxylase
  • PEPCK phosphoenolpyruvate carboxykinase
  • FIG. 2b shows the strategy for metabolic engineering by introducing a cytosolic expressed pyruvate carboxylase gene (PYC2) from yeast into the cells.
  • PYC2 cytosolic expressed pyruvate carboxylase gene
  • LDH lactate dehydrogenase
  • NAD + is reduced by the cytoplasmic malate dehydrogenase (MDH cyt ).
  • ME malate enzyme
  • the recombinant cytoplasmic pyruvate carboxylase competes with the lactate dehydrogenase for the substrate pyruvate and extracts this substrate amount for the formation of lactate.
  • the malate dehydrogenase reaction leads to the regression of NAD + from NADH, which is again available for glycolysis at the stage of glyceraldehyde-3-phosphate dehydrogenase. This step reduces the importance of the lactate dehydrogenase reaction for the regression of NAD + .
  • an excess of malate can be deearboxylated with the formation of NADPH by the presence of the malate enzyme with the regression of pyruvate. NADPH is used for many constructive processes and syntheses.
  • the glueose consumption could be reduced by a factor of 4 and the glutamine consumption by 2 times compared to the conventional BHK cells.
  • a 1.4 times higher ATP content with comparable good growth could be demonstrated (Tab. 1).
  • the confirmation that glucose-carbon really does get into the citrate cycle was carried out with the help of radioactively labeled glucose and labeled pyruvate through the release of radioactive 14 C0 2 and a higher glucose oxidation underpinned.
  • the cell-specific oxygen consumption which is an indication of the oxidative metabolism, increased by a factor of 3 in the recombinant, PYC2-expressing cell line compared to the original cell.
  • the lower amounts of substrate used result in a higher amount of product per substrate used, so that these recombinant cell lines can now be used to produce pharmaceutical proteins over a longer period of time using the existing culture medium, which ultimately contributes to reducing the overall production costs.
  • P-lasmids were produced in a manner known per se which carry the PYC2 gene from yeast and accordingly transfect BHK cells with them. It is clear to the person skilled in the art that other cells can also be used instead of the BHK cells. Success was verified using metabolism-specific data. The flux of glucose in the TCA is slightly increased. The oxygen consumption rate, an indication of the degree of oxidative phosphorylation, is also increased.
  • EPO will be used as a model protein to investigate whether cell-specific productivity or the space-time yield in the fermenter can be increased.
  • the cDNA of pyruvate carboxylase (PYC2, isoenzyme 2) from Saccharomyces cerevisiae was obtained from R. Stucka (Stucka et al., 1991). To see possible interactions of the coding
  • the cDNA was removed by endonuclease restriction and ligation after Methods well known in the prior art with small PCR fragments trimmed down to the essential coding sequences (FIG. 3).
  • the modified cDNA was placed under the transertion control of a CMV promoter.
  • the resulting pCMVPYC2 plasmid also contains an ampicillin resistance gene. It is clear that other promoters and resistance genes or selection markers in general can also be used.
  • Figure 3 shows the liberation of the 5 'and 3' region of the PYC2 gene from flanking yeast-specific sequences.
  • a 678 bp fragment was cut out from the 5 'end with Pvull, the missing 381 bp was ligated with PCR (polymerase chain reaction) via specific primers and a HindIII site was added before the coding sequence.
  • the plasmid pCMVSHE-PYC2 was mixed with a neomycin resistance plasmid (pAG60) using the calcium phosphate coprecipitation method (Maitland and McDougall, 1977) in BHK-21A cells according to a modified protocol by Kriegler ( Kriegler, 1990) transfected (Fig. 4). After removing the precipitates, no osmotic shock was applied by adding glycine. The latter measures can, however, be carried out if the practical circumstances so require. There are also their transfection methods known in the prior art can be used.
  • Figure 4 is a schematic drawing of the expression vector pCMVSHE-PYC2 based on the standard expression vector pCMVSHE. It means: CMV: Cytomegalovirus immediate early enhancer promoter; SVpA: late polydenylation signal, splice sites, SV40 early late splice sites.
  • CMV Cytomegalovirus immediate early enhancer promoter
  • SVpA late polydenylation signal, splice sites, SV40 early late splice sites.

Abstract

L'invention concerne un procédé d'amélioration du métabolisme d'énergie primaire de lignées cellulaires de mammifères, selon lequel un gène de structure pour une levure-pyruvate carboxylase cytoplasmique est introduit, par des techniques génétiques, dans les cellules de mammifères et est soumis à une expression.
EP00910644A 1999-02-05 2000-02-07 Procede d'amelioration du metabolisme d'energie primaire de lignees cellulaires de mammiferes Withdrawn EP1144647A2 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19904794A DE19904794A1 (de) 1999-02-05 1999-02-05 Verfahren zur Verbesserung des Primärstoffwechsels von Säugerzelllinien
DE19904794 1999-02-05
PCT/EP2000/000939 WO2000046378A2 (fr) 1999-02-05 2000-02-07 Procede d'amelioration du metabolisme d'energie primaire de lignees cellulaires de mammiferes

Publications (1)

Publication Number Publication Date
EP1144647A2 true EP1144647A2 (fr) 2001-10-17

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EP00910644A Withdrawn EP1144647A2 (fr) 1999-02-05 2000-02-07 Procede d'amelioration du metabolisme d'energie primaire de lignees cellulaires de mammiferes

Country Status (6)

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US (2) US6291238B1 (fr)
EP (1) EP1144647A2 (fr)
JP (1) JP2002535991A (fr)
CA (1) CA2360753A1 (fr)
DE (1) DE19904794A1 (fr)
WO (1) WO2000046378A2 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
MY121380A (en) 1998-04-13 2006-01-28 Univ Georgia Pyruvate carboxylase overexpression for enhanced production of oxaloacetate-derived biochemicals in microbial cells
WO2001027258A2 (fr) * 1999-10-13 2001-04-19 The University Of Georgia Research Foundation, Inc. Systeme et procedes d'expression de proteines a haut rendement
AU2007352618B2 (en) 2007-05-02 2013-07-18 Boehringer Ingelheim Animal Health USA Inc. DNA plasmids having improved expression and stability
DE102008013899A1 (de) 2008-03-12 2009-09-17 F. Hoffmann-La Roche Ag Verfahren zur Herstellung rekombinanter Proteine bei konstantem Gehalt von pCO2 im Medium
JP2011516473A (ja) * 2008-04-04 2011-05-26 ショール，ロバート 医薬組成物
EP2758424B1 (fr) 2011-09-21 2019-03-06 F.Hoffmann-La Roche Ag Culture avec profil co2
CN104822832A (zh) * 2012-11-23 2015-08-05 帝斯曼知识产权资产管理有限公司 衣康酸和衣康酸甲酯生产
KR102205701B1 (ko) 2013-12-06 2021-01-22 삼성전자주식회사 피루베이트 카르복실라제가 불활성화되거나 감소된 효모 세포 및 그를 이용한 락테이트를 생산하는 방법

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JP3002735B2 (ja) * 1991-09-27 2000-01-24 農林水産省食品総合研究所長 大豆のホスホエノールピルビン酸カルボキシラーゼ遺伝子
JPH06305963A (ja) * 1993-04-21 1994-11-01 Taisho Pharmaceut Co Ltd 疲労改善剤
JP3880636B2 (ja) * 1994-01-10 2007-02-14 味の素株式会社 発酵法によるｌ−グルタミン酸の製造法

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Also Published As

Publication number Publication date
US6291238B1 (en) 2001-09-18
CA2360753A1 (fr) 2000-08-10
WO2000046378A2 (fr) 2000-08-10
DE19904794A1 (de) 2000-08-10
WO2000046378A3 (fr) 2000-11-30
US6706524B2 (en) 2004-03-16
US20020052046A1 (en) 2002-05-02
JP2002535991A (ja) 2002-10-29

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