Mitochondrial dysfunction remodels one-carbon metabolism in human cells
Ontology highlight
ABSTRACT:
INSTRUMENT(S): LTQ Orbitrap
ORGANISM(S): Homo Sapiens (ncbitaxon:9606)
SUBMITTER: Steven A. Carr
PROVIDER: MSV000079791 | MassIVE | Thu Jun 02 12:08:00 BST 2016
REPOSITORIES: MassIVE
Similar Datasets
Project description:Mitochondrial integrated stress response emerged as a major adaptive pathway to respiratory chain deficiency, but tissue-specifics of its regulation or how it adapts to different levels of mitochondrial dysfunction are largely unknown. Here we report that diverse levels of mitochondrial cardiomyopathy activate mitoISR, including high production of FGF21, a cytokine with both paracrine and endocrine function, shown to be induced by respiratory chain dysfunction. Remarkably, although being fully dispensable for the cell-autonomous and systemic responses to severe mitochondrial cardiomyopathy, in the conditions of mild-to-moderate cardiac OXPHOS dysfunction, FGF21 regulates a portion of the mitoISR. In the absence of FGF21, a large part of the metabolic adaptation to mitochondrial dysfunction (one-carbon metabolism, transsulfuration and serine and proline biosynthesis) is strongly blunted, independent of the primary mitoISR activator ATF4. Collectively, our work highlights the complexity of mitochondrial stress responses by revealing the importance of the tissue-specificity and dose-dependency of the mitoISR.
2022-02-04 | GSE195947 | GEO
Project description:Mitochondrial DNA (mtDNA) encodes essential components of the respiratory chain and loss of mtDNA leads to mitochondrial dysfunction and neurodegeneration. Mitochondrial transcription factor A (TFAM) is an essential component of mtDNA replication and a regulator of mitochondrial copy number in cells. Studies have shown that TFAM knockdown leads to mitochondrial dysfunction and respiratory chain deficiencies. Using gene expression analysis, we aimed to investigate the effects of mtDNA dysfunction in the CNS at the molecular level. We used microarray analysis to investigate gene expression in cases of mitochondrial dysfunction in the CNS. RNA was purified from the late third instar larval CNS from control larvae, or larvae over-expressing mitochondrial transcription factor A (TFAM) in post-mitotic neurons using the neuron specific driver nsyb-Gal4. Three replicates are included for each condition.
2013-12-20 | E-GEOD-53509 | biostudies-arrayexpress
Project description:Mitochondrial DNA (mtDNA) encodes essential components of the respiratory chain and loss of mtDNA leads to mitochondrial dysfunction and neurodegeneration. Mitochondrial transcription factor A (TFAM) is an essential component of mtDNA replication and a regulator of mitochondrial copy number in cells. Studies have shown that TFAM knockdown leads to mitochondrial dysfunction and respiratory chain deficiencies. ATP synthase is Complex V of the mitochondrial respiratory chain. It is driven by a proton gradient between the intermembrane space and the mitochondrial matrix and generates the majority of cellular ATP. The knockdown of coupling factor 6 (Cf6), one of the components of the proton channel F0, causes dysfunction in the complex, leading to mitochondrial dysfunction and respiratory chain deficiencies. Using gene expression analysis, we aimed to investigate the effects of mtDNA dysfunction in the CNS at the molecular level.
2013-12-20 | GSE53509 | GEO
Project description:Mitochondrial integrated stress response emerged as a major adaptive pathway to respiratory chain deficiency, but tissue-specifics of its regulation or how it adapts to different levels of mitochondrial dysfunction are largely unknown. Here we report that diverse levels of mitochondrial cardiomyopathy activate mitoISR, including high production of FGF21, a cytokine with both paracrine and endocrine function, shown to be induced by respiratory chain dysfunction. Remarkably, although being fully dispensable for the cell-autonomous and systemic responses to severe mitochondrial cardiomyopathy, in the conditions of mild-to-moderate cardiac OXPHOS dysfunction, FGF21 regulates a portion of the mitoISR. In the absence of FGF21, a large part of the metabolic adaptation to mitochondrial dysfunction (one-carbon metabolism, transsulfuration and serine and proline biosynthesis) is strongly blunted, independent of the primary mitoISR activator ATF4. Collectively, our work highlights the complexity of mitochondrial stress responses by revealing the importance of the tissue-specificity and dose-dependency of the mitoISR.
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Project description:The mitochondrial serine catabolism to formate induces a metabolic switch to a hypermetabolic state with high rates of glycolysis, purine synthesis and pyrimidine synthesis. While formate is a purine precursor it is not obvious link between formate and pyrimidine synthesis. Methods Here we combine phospho-proteome and metabolic profiling to determine how formate induces pyrimidine synthesis. We discover that formate induces CAD phosphorylation. Mechanistically formate induces mTORC1 activity as quantified by S6K1 phosphorylation, which is known to phosphorylate CAD and increase its enzymatic activity. Treatment with the allosteric mTORC1 inhibitor rapamycin abrogates CAD phosphorylation and pyrimidine synthesis induced by formate. We conclude that formate activates mTORC1 and induces pyrimidine synthesis via increasing CAD activity.
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Project description:MTHFD2 is a mitochondrial enzyme within the folate cycle of one carbon metabolism. We found that MTHFD2 deficiency leads to impaired proliferation and induction of FoxP3 expression in Th17 cells and Treg cells differentiated in low TGFß conditions. Mechanistically, this occured through depleted purine pools, accumulation of purine synthesis intermediates, dampened mTORC1 activity, and altered DNA and histone methylation.
2021-11-12 | GSE180356 | GEO
Project description:Objective: To study if diabetic and insulin-resistant states lead to mitochondrial dysfunction in the liver, or alternatively, if there is adaption of mitochondrial function to these states in the long-term range. Results: High-fat diet (HFD) caused insulin resistance and severe hepatic lipid accumulation, but respiratory chain parameters were unchanged. Livers from insulin-resistant IR/IRS-1+/- mice had normal lipid contents and normal respiratory chain parameters, however showed mitochondrial uncoupling. Livers from severely hyperglycemic and hypoinsulimic, streptozotocin (STZ)-treated mice had massively depleted lipid levels, but respiratory chain abundance was unchanged. However, their mitochondria showed increased abundance and activity of the respiratory chain, which was better coupled compared to controls. Conclusions: Insulin resistance, either induced by obesity or by genetic manipulation, does not cause mitochondrial dysfunction in the liver of mice. However, severe insulin deficiency and high blood glucose levels in mice cause an enhanced performance of the respiratory chain, probably in order to maintain the high energy requirement of the unsuppressed gluconeogenesis. We performed gene expression microarray analysis on liver tissue derived from mice treated with STZ or standard diet (control).
2013-12-10 | E-GEOD-39752 | biostudies-arrayexpress
Project description:The introduction of alternative CO2-fixing pathways such as formate synthesis and assimilation may improve the efficiency of biological carbon fixation that appears to be limited by the enzymatic properties of ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO). Here we aimed to establish a formate assimilation pathway in the model cyanobacterium Synechocystis sp. PCC 6803. The formate-tetrahydrofolate ligase (FTL) from Methylobacterium extorquens AM1 was expressed in Synechocystis to enable formate assimilation and reduce the loss of fixed carbon in the photorespiratory pathway. Transgenic strains accumulated serine and 3-phosphoglycerate, and consumed more 2-phosphoglycolate and glycine, which seemed to reflect the efficient utilization of formate. However, labelling experiments showed that the serine accumulation was not due to the expected incorporation of formate. DNA-microarray experiments were performed to analyze possible transcriptome changes due to ftl expression. Marked changes in expression of genes encoding proteins associated with serine biosynthesis and enzymes involved in nitrogen and C1 metabolism revealed that ftl expression had a regulatory impact on these metabolic routes. Our results indicate that the expression of new pathways could have a severe impact on the cellular regulatory network, which hampers the establishment of newly designed pathways.
2020-01-17 | GSE143785 | GEO
Project description:This is the model described in the article:
In silico experimentation with a model of hepatic mitochondrial folate metabolism.
H. Frederik Nijhout, Michael C Reed, Shi-Ling Lam, Barry Shane, Jesse F Gregory and Cornelia M Ulrich, Theor Biol Med Model
2006,3:40; PubmedID: 17150100
; DOI: 10.1186/1742-4682-3-40
;
Abstract:
BACKGROUND: In eukaryotes, folate metabolism is compartmentalized and occurs in both the cytosol and the mitochondria. The function of this compartmentalization and the great changes that occur in the mitochondrial compartment during embryonic development and in rapidly growing cancer cells are gradually becoming understood, though many aspects remain puzzling and controversial.
APPROACH: We explore the properties of cytosolic and mitochondrial folate metabolism by experimenting with a mathematical model of hepatic one-carbon metabolism. The model is based on known biochemical properties of mitochondrial and cytosolic enzymes. We use the model to study questions about the relative roles of the cytosolic and mitochondrial folate cycles posed in the experimental literature. We investigate: the control of the direction of the mitochondrial and cytosolic serine hydroxymethyltransferase (SHMT) reactions, the role of the mitochondrial bifunctional enzyme, the role of the glycine cleavage system, the effects of variations in serine and glycine inputs, and the effects of methionine and protein loading.
CONCLUSION: The model reproduces many experimental findings and gives new insights into the underlying properties of mitochondrial folate metabolism. Particularly interesting is the remarkable stability of formate production in the mitochondria in the face of large changes in serine and glycine input. The model shows that in the presence of the bifunctional enzyme (as in embryonic tissues and cancer cells), the mitochondria primarily support cytosolic purine and pyrimidine synthesis via the export of formate, while in adult tissues the mitochondria produce serine for gluconeogenesis.
This model does not reproduce the results in the article completely, but most steady state concentrations are in a range of 10% around the published values. Also parameterscans give nearly identical results as shown in the article.
In the SBML version model the volumes of the mitochondrion, the cytoplasm and the cell were all set to one to obtain the same equations as described in the supplemental materials of the article. The total folate is equally split between the cytosol and the mitochondrion and divided by 3/4 for the cytosol and 1/4 for the mitochondrion, respectively. To obtain an SBML model in which the volumes of the compartments, cytosol
and mito
, are used, the model needs to be altered as follows:
for the initial distribution of folate the terms 3/4 and 1/4 have to be replaced by volumes of cytosol and mitochondria respectively
in the transport reactions between mitochondrion and cytosol the stoichiometry of the mitochondrial reactants has to be set from 3 to 1 and in the first part of the according rate laws the factor mito/3
should simply be replaced with mito
.
the stoichiometries of src
and dmg
have to be changed to cell/mito
for mitchondrial and cell/cytosol
for cytosolic reactions involving these two species.
While the concentrations stay the same after these alteration, the reaction fluxes change by a factor of cytosol
and mito
for cytosolic and mitchondrial reactions, respectively.
Originally created by libAntimony v1.3 (using libSBML 3.4.1)
This model originates from BioModels Database: A Database of Annotated Published Models (http://www.ebi.ac.uk/biomodels/). It is copyright (c) 2005-2011 The BioModels.net Team.
To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication
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To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.
2005-01-01 | MODEL1007200000 | BioModels
Project description:Objective: To study if diabetic and insulin-resistant states lead to mitochondrial dysfunction in the liver, or alternatively, if there is adaption of mitochondrial function to these states in the long-term range. Results: High-fat diet (HFD) caused insulin resistance and severe hepatic lipid accumulation, but respiratory chain parameters were unchanged. Livers from insulin-resistant IR/IRS-1+/- mice had normal lipid contents and normal respiratory chain parameters, however showed mitochondrial uncoupling. Livers from severely hyperglycemic and hypoinsulimic, streptozotocin (STZ)-treated mice had massively depleted lipid levels, but respiratory chain abundance was unchanged. However, their mitochondria showed increased abundance and activity of the respiratory chain, which was better coupled compared to controls. Conclusions: Insulin resistance, either induced by obesity or by genetic manipulation, does not cause mitochondrial dysfunction in the liver of mice. However, severe insulin deficiency and high blood glucose levels in mice cause an enhanced performance of the respiratory chain, probably in order to maintain the high energy requirement of the unsuppressed gluconeogenesis.
2013-12-10 | GSE39752 | GEO