Regulation of respiratory complex I assembly by FMN cofactor targeting
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE249118 | GEO | 2023/12/29
REPOSITORIES: GEO
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Project description:Respiratory complex I plays a crucial role in the mitochondrial electron transport chain and shows promise as a therapeutic target for various human diseases. While most studies focus on inhibiting complex I at the Q-site, little is known about inhibitors targeting other sites within the complex. In this study, we demonstrate that diphenyleneiodonium (DPI), a known N-site inhibitor, uniquely affects the stability of complex I by inhibiting its flavin cofactor FMN. Treatment with DPI blocks the final stage of complex I assembly, leading to the accumulation of assembly intermediates that lack the N-module. Remarkably, high-dose DPI treatment can completely and reversibly degrade complex I in different cellular models. The mechanism involves the accumulation of DPI in mitochondria, where it reacts with FMN, depleting the effective pool of FMN and halting complex I maturation. Consistently, growing cells in medium lacking the FMN precursor riboflavin or knocking out the mitochondrial FAD carrier gene SLC25A32 results in complex I degradation and impairs complex I-dependent respiration. Overall, our findings establish a direct connection between mitochondrial flavin homeostasis and complex I stability and assembly, paving the way for novel pharmacological strategies to regulate respiratory complex I.
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Project description:Regulation of the turnover of complex I (CI), the largest mitochondrial respiratory chain complex remains enigmatic, despite huge advancement in understanding its structure and the assembly steps in recent years. Although some studies indicated that CI might be remodelled in response to various stimuli, the mechanism mediating these putative changes is unknown. Here, we report that the NADH-oxidising N-module which sits on the tip of the CI peripheral arm is turned over at a higher rate and largely independently of the rest of the complex. The N-module turnover is mediated by mitochondrial matrix protease ClpXP, which selectively removes and degrades damaged core subunits. The observed mechanism seems to be a safeguard against accumulation of dysfunctional CI arising from inactivation of the N-module subunits due to attrition caused by extensive redox activity. This CI salvage pathway maintains highly functional CI and healthy mitochondria through an energetically favourable mechanism that demands much lower energetic cost than de novo synthesis and reassembly of the entire CI.
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Project description:The Mitochondrial Complex I Assembly (MCIA) complex is essential for the biogenesis of respiratory Complex I (CI), the first enzyme in the respiratory chain, which has been linked to Alzheimer’s disease (AD) pathogenesis. However, how MCIA facilitates CI assembly, and how it is linked with AD pathogenesis, is poorly understood. Here we report the structural basis of the complex formation between the MCIA subunits ECSIT and ACAD9. ECSIT binding induces a major conformational change in the FAD-binding loop of ACAD9, releasing the FAD cofactor and converting ACAD9 from a fatty acid β-oxidation (FAO) enzyme to a CI assembly factor. We provide evidence that ECSIT phosphorylation downregulates its association with ACAD9 and is reduced in neuronal cells upon exposure to amyloid-β (Aβ) oligomers. These findings advance our understanding of the MCIA complex assembly and suggest a possible role for ECSIT in the reprogramming of bioenergetic pathways linked to Aβ toxicity, a hallmark of AD.
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Project description:The oxidative phosphorylation (OXPHOS) system localized in the inner mitochondrial membrane secures production of the majority of ATP in mammalian organisms. Individual OXPHOS complexes form supramolecular assemblies termed supercomplexes. The complexes are linked not only by their function but also by interdependence of individual complex biogenesis or maintenance. For instance, cytochrome c oxidase (cIV, COX) or cytochrome bc1 complex (cIII) deficiencies affect the level of fully assembled NADH dehydrogenase (cI) in monomeric as well as supercomplex forms. It was hypothesized that cI is affected at the level of enzyme assembly as well as at the level of cI stability and maintenance. However, the true nature of interdependency between cI and cIV is not fully understood yet. We used a HEK293 cellular model where the COX4 subunit was completely knocked out, serving as an ideal system to study interdependency of cI and cIV, as early phases of cIV assembly process are disrupted. Total absence of cIV was accompanied by profound deficiency of cI, documented by decrease in the levels of cI subunits and significantly reduced amount of assembled cI. Supercomplexes assembled from cI, cIII and cIV were missing in COX4 KO due to loss of cIV and decrease in cI amount. Pulse-chase metabolic labelling of mtDNA-encoded proteins uncovered a decrease in the translation of cIV and cI subunits. Moreover, partial impairment of mitochondrial protein synthesis correlated with decreased content of mitochondrial ribosomal proteins. In addition, complexome profiling revealed accumulation of cI assembly intermediates indicating that cI biogenesis, rather than stability, was the affected process. We propose, that impairment of mitochondrial protein synthesis caused by cIV deficiency represents one of the mechanisms which may couple biogenesis of cI and cIV.
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Project description:The Mitochondrial Complex I Assembly (MCIA) complex is essential for the biogenesis of respiratory Complex I (CI), the first enzyme in the respiratory chain, which has been linked to Alzheimer’s disease (AD) pathogenesis. However, how MCIA facilitates CI assembly, and how it is linked with AD pathogenesis, is poorly understood. Here we report the structural basis of the complex formation between the MCIA subunits ECSIT and ACAD9. ECSIT binding induces a major conformational change in the FAD-binding loop of ACAD9, releasing the FAD cofactor and converting ACAD9 from a fatty acid β-oxidation (FAO) enzyme to a CI assembly factor. We provide evidence that ECSIT phosphorylation downregulates its association with ACAD9 and is reduced in neuronal cells upon exposure to amyloid-β (Aβ) oligomers. These findings advance our understanding of the MCIA complex assembly and suggest a possible role for ECSIT in the reprogramming of bioenergetic pathways linked to Aβ toxicity, a hallmark of AD.
2023-12-13 | PXD042858 | Pride
Project description:Complex I (CI) is the first enzyme of the mitochondrial respiratory chain and couples the electron transfer with proton pumping. Mutations in genes encoding CI subunits can frequently cause inborn metabolic errors. We applied proteome and metabolome profiling of patient-derived cells harboring pathogenic mutations in two distinct CI genes to elucidate underlying pathomechanisms on the molecular level. Our results indicated that the electron transfer within CI was interrupted in both patients by different mechanisms. We showed that the biallelic mutations in NDUFS1 led to a decreased stability of the entire N-module of CI and disrupted the electron transfer between two iron–sulfur clusters. Strikingly interesting and in contrast to the proteome, metabolome profiling illustrated that the pattern of dysregulated metabolites was almost identical in both patients, such as the inhibitory feedback on the TCA cycle and altered glutathione levels, indicative for reactive oxygen species (ROS) stress. Our findings deciphered pathological mechanisms of CI deficiency to better understand inborn metabolic errors.
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Project description:Porcine reproductive and respiratory disease (PRRS) is the most important disease in swine industry worldwide. However, strategies such as vaccination and good biosecurity are not consistently successful to eliminate PRRSV. Although some gene expression pathways have been explored recently, host molecular pathways blocked by PRRSV and the protective immune response expressed in pigs resistant to PRRSV are largely unknown. In order to answer these questions, we herein characterize changes in blood gene expression in pigs responding differentially to infection with a well characterized type 2 (North American) PRRSV isolate. Samples are those collected through the PRRS Host Genetics Consortium (PHGC). Samples were those from Tempus tube collected blood of PHGC pigs selected from four response groups according to their serum viral load (0-21 days post infection) and weight gain (0-42 dpi) and characterized as low vs. high viral load and low vs high weight gain . block reference design was used to accommodate samples from 4 treatment groups.
2012-09-26 | E-GEOD-41144 | biostudies-arrayexpress
Project description:We aim to determine the physiological impact of inactivating E2F in muscles and in adipose cells in vivo. To uncover the mechanism of action of E2F in each tissue we investigated the similarities between E2F-deficient tissues by comparing the proteomic profiles between muscles and fat cells. Our findings revealed that E2F is required in fat cells to promote the storage of fat and the synthesis of trehalose, which was restored by feeding animals in high sugar diet.
Multiplexed quantitative proteomics was performed using TMT10-plex reagents on an Orbitrap Fusion mass spectrometer using the SPS-MS3 method.
Two sample sets - fatbody samples and samples of thoracic muscles - were analyzed using two TMT sets. Twelve high pH reversed-phase chromatography fractions were analyzed per sample set.
The samples in each set were TMT-labeled as follows:
Fatbody samples:
WT FB MS1; 126
DP FB MS 1; 127n
WT FB MS2; 127c
DP FB MS 2; 128n
WT FB MS3; 128c
DP FB MS 3; 129n
Thoracic muscles samples:
Mef>Ci 1; 126
Mef>Dpi 1; 127n
Mef>Ci 2; 127c
Mef>Dpi 2; 128n
Mef>Ci 3; 128c
Mef>Dpi 3; 129n
Mef>Ci 4; 129c
Mef>Dpi 4; 130n
2021-02-11 | MSV000086854 | MassIVE
Project description:Porcine reproductive and respiratory disease (PRRS) is the most important disease in swine industry worldwide. However, strategies such as vaccination and good biosecurity are not consistently successful to eliminate PRRSV. Although some gene expression pathways have been explored recently, host molecular pathways blocked by PRRSV and the protective immune response expressed in pigs resistant to PRRSV are largely unknown. In order to answer these questions, we herein characterize changes in blood gene expression in pigs responding differentially to infection with a well characterized type 2 (North American) PRRSV isolate. Samples are those collected through the PRRS Host Genetics Consortium (PHGC). Samples were those from Tempus tube collected blood of PHGC pigs selected from four response groups according to their serum viral load (0-21 days post infection) and weight gain (0-42 dpi) and characterized as low vs. high viral load and low vs high weight gain .
2012-09-26 | GSE41144 | GEO
Project description:Targeting of specific metabolic pathways in tumor cells has the potential to sensitize them to immune-mediated attack. Here we provide evidence for a specific means of mitochondrial respiratory Complex I (CI) inhibition that improves tumor immunogenicity and sensitivity to immune checkpoint blockade (ICB). Targeted genetic deletion of the CI subunits Ndufs4 and Ndufs6, but not other subunits, induces an immune-dependent tumor growth attenuation in mouse melanoma models. We show that deletion of Ndufs4 induces expression of the transcription factor Nlrc5 and genes in the MHC class-I antigen presentation and processing pathway. This induction of MHC-related genes is driven by an accumulation of pyruvate dehydrogenase-dependent mitochondrial acetyl-CoA downstream of CI subunit deletion. This work provides a novel functional modality by which selective CI inhibition restricts tumor growth, suggesting that specific targeting of Ndufs4, or related CI subunits, increases T-cell mediated immunity and sensitivity to ICB.
2024-10-05 | GSE263533 | GEO