1
|
Sinenko SA, Tomilin AN. Metabolic control of induced pluripotency. Front Cell Dev Biol 2024; 11:1328522. [PMID: 38274274 PMCID: PMC10808704 DOI: 10.3389/fcell.2023.1328522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 12/13/2023] [Indexed: 01/27/2024] Open
Abstract
Pluripotent stem cells of the mammalian epiblast and their cultured counterparts-embryonic stem cells (ESCs) and epiblast stem cells (EpiSCs)-have the capacity to differentiate in all cell types of adult organisms. An artificial process of reactivation of the pluripotency program in terminally differentiated cells was established in 2006, which allowed for the generation of induced pluripotent stem cells (iPSCs). This iPSC technology has become an invaluable tool in investigating the molecular mechanisms of human diseases and therapeutic drug development, and it also holds tremendous promise for iPSC applications in regenerative medicine. Since the process of induced reprogramming of differentiated cells to a pluripotent state was discovered, many questions about the molecular mechanisms involved in this process have been clarified. Studies conducted over the past 2 decades have established that metabolic pathways and retrograde mitochondrial signals are involved in the regulation of various aspects of stem cell biology, including differentiation, pluripotency acquisition, and maintenance. During the reprogramming process, cells undergo major transformations, progressing through three distinct stages that are regulated by different signaling pathways, transcription factor networks, and inputs from metabolic pathways. Among the main metabolic features of this process, representing a switch from the dominance of oxidative phosphorylation to aerobic glycolysis and anabolic processes, are many critical stage-specific metabolic signals that control the path of differentiated cells toward a pluripotent state. In this review, we discuss the achievements in the current understanding of the molecular mechanisms of processes controlled by metabolic pathways, and vice versa, during the reprogramming process.
Collapse
Affiliation(s)
- Sergey A. Sinenko
- Institute of Cytology, Russian Academy of Sciences, Saint-Petersburg, Russia
| | | |
Collapse
|
2
|
Buzzard E, McLaren M, Bragoszewski P, Brancaccio A, Ford H, Daum B, Kuwabara P, Collinson I, Gold V. The consequence of ATP synthase dimer angle on mitochondrial morphology studied by cryo-electron tomography. Biochem J 2024; 481:BCJ20230450. [PMID: 38164968 PMCID: PMC10903453 DOI: 10.1042/bcj20230450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/12/2023] [Accepted: 01/02/2024] [Indexed: 01/03/2024]
Abstract
Mitochondrial ATP synthases form rows of dimers, which induce membrane curvature to give cristae their characteristic lamellar or tubular morphology. The angle formed between the central stalks of ATP synthase dimers varies between species. Using cryo-electron tomography and sub-tomogram averaging, we determined the structure of the ATP synthase dimer from the nematode worm C. elegans and show that the dimer angle differs from previously determined structures. The consequences of this species-specific difference at the dimer interface were investigated by comparing C. elegans and S. cerevisiae mitochondrial morphology. We reveal that C. elegans has a larger ATP synthase dimer angle with more lamellar (flatter) cristae when compared to yeast. The underlying cause of this difference was investigated by generating an atomic model of the C. elegans ATP synthase dimer by homology modelling. A comparison of our C. elegans model to an existing S. cerevisiae structure reveals the presence of extensions and rearrangements in C. elegans subunits associated with maintaining the dimer interface. We speculate that increasing dimer angles could provide an advantage for species that inhabit variable-oxygen environments by forming flatter more energetically efficient cristae.
Collapse
Affiliation(s)
| | | | - Piotr Bragoszewski
- Instytut Biologii Doswiadczalnej im Marcelego Nenckiego Polskiej Akademii Nauk, Warsaw, Poland
| | | | - Holly Ford
- University of Bristol, Bristol, United Kingdom
| | | | | | | | - Vicki Gold
- University of Exeter, Exeter, United Kingdom
| |
Collapse
|
3
|
Zhang Y, Hu Y, Wang Z, Lin X, Li Z, Ren Y, Zhao J. The translocase of the inner mitochondrial membrane 22-2 is required for mitochondrial membrane function during Arabidopsis seed development. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4427-4448. [PMID: 37105529 DOI: 10.1093/jxb/erad141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 04/27/2023] [Indexed: 06/19/2023]
Abstract
The carrier translocase (also known as translocase of the inner membrane 22; TIM22 complex) is an important component of the mitochondrial protein import apparatus. However, the biological functions of AtTIM22-2 in Arabidopsis remain poorly defined. Here, we report studies on two tim22-2 mutants that exhibit defects in embryo and endosperm development, leading to seed abortion. AtTIM22-2, which was localized in mitochondria, was widely expressed in embryos and in various seedling organs. Loss of AtTIM22-2 function resulted in irregular mitochondrial cristae, decreased respiratory activity, and a lower membrane potential, together with changes in gene expression and enzyme activity related to reactive oxygen species (ROS) metabolism, leading to increased accumulation of ROS in the embryo. The levels of transcripts encoding mitochondrial protein import components were also altered in the tim22-2 mutants. Furthermore, mass spectrometry, bimolecular fluorescence complementation and co-immunoprecipitation assays revealed that AtTIM22-2 interacted with AtTIM23-2, AtB14.7 (a member of Arabidopsis OEP16 family encoded by At2G42210), and AT5G27395 (mitochondrial inner membrane translocase complex, subunit TIM44-related protein). Taken together, these results demonstrate that AtTIM22-2 is essential for maintaining mitochondrial membrane functions during seed development. These findings lay the foundations for a new model of the composition and functions of the TIM22 complex in higher plants.
Collapse
Affiliation(s)
- Yuqin Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yuanyuan Hu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zhiqin Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiaodi Lin
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zihui Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yafang Ren
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| |
Collapse
|
4
|
Lazzarino G, Mangione R, Saab MW, Tavazzi B, Pittalà A, Signoretti S, Di Pietro V, Lazzarino G, Amorini AM. Traumatic Brain Injury Alters Cerebral Concentrations and Redox States of Coenzymes Q 9 and Q 10 in the Rat. Antioxidants (Basel) 2023; 12:antiox12050985. [PMID: 37237851 DOI: 10.3390/antiox12050985] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 04/14/2023] [Accepted: 04/21/2023] [Indexed: 05/28/2023] Open
Abstract
To date, there is no information on the effect of TBI on the changes in brain CoQ levels and possible variations in its redox state. In this study, we induced graded TBIs (mild TBI, mTBI and severe TBI, sTBI) in male rats, using the weight-drop closed-head impact acceleration model of trauma. At 7 days post-injury, CoQ9, CoQ10 and α-tocopherol were measured by HPLC in brain extracts of the injured rats, as well as in those of a group of control sham-operated rats. In the controls, about the 69% of total CoQ was in the form of CoQ9 and the oxidized/reduced ratios of CoQ9 and CoQ10 were, respectively, 1.05 ± 0.07 and 1.42 ± 0.17. No significant changes in these values were observed in rats experiencing mTBI. Conversely, in the brains of sTBI-injured animals, an increase in reduced and a decrease in oxidized CoQ9 produced an oxidized/reduced ratio of 0.81 ± 0.1 (p < 0.001 compared with both controls and mTBI). A concomitant decrease in both reduced and oxidized CoQ10 generated a corresponding oxidized/reduced ratio of 1.38 ± 0.23 (p < 0.001 compared with both controls and mTBI). An overall decrease in the concentration of the total CoQ pool was also found in sTBI-injured rats (p < 0.001 compared with both controls and mTBI). Concerning α-tocopherol, whilst no differences compared with the controls were found in mTBI animals, a significant decrease was observed in rats experiencing sTBI (p < 0.01 compared with both controls and mTBI). Besides suggesting potentially different functions and intracellular distributions of CoQ9 and CoQ10 in rat brain mitochondria, these results demonstrate, for the first time to the best of knowledge, that sTBI alters the levels and redox states of CoQ9 and CoQ10, thus adding a new explanation to the mitochondrial impairment affecting ETC, OXPHOS, energy supply and antioxidant defenses following sTBI.
Collapse
Affiliation(s)
- Giacomo Lazzarino
- Departmental Faculty of Medicine and Surgery, UniCamillus-Saint Camillus International University of Health and Medical Sciences, Via di Sant'Alessandro 8, 00131 Rome, Italy
| | - Renata Mangione
- Department of Basic Biotechnological Sciences, Intensive and Perioperative Clinics, Catholic University of the Sacred Heart of Rome, Largo F. Vito 1, 00168 Rome, Italy
| | - Miriam Wissam Saab
- Department of Biomedical and Biotechnological Sciences, Division of Medical Biochemistry, University of Catania, Via S. Sofia 97, 95123 Catania, Italy
| | - Barbara Tavazzi
- Departmental Faculty of Medicine and Surgery, UniCamillus-Saint Camillus International University of Health and Medical Sciences, Via di Sant'Alessandro 8, 00131 Rome, Italy
| | - Alessandra Pittalà
- Department of Biomedical and Biotechnological Sciences, Division of Medical Biochemistry, University of Catania, Via S. Sofia 97, 95123 Catania, Italy
| | - Stefano Signoretti
- Departmental Faculty of Medicine and Surgery, UniCamillus-Saint Camillus International University of Health and Medical Sciences, Via di Sant'Alessandro 8, 00131 Rome, Italy
- Department of Emergency and Urgency, Division of Neurosurgery, S. Eugenio/CTO Hospital, A.S.L. Roma2 Piazzale dell'Umanesimo 10, 00144 Rome, Italy
| | - Valentina Di Pietro
- Neurotrauma and Ophthalmology Research Group, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
- National Institute for Health Research Surgical Reconstruction and Microbiology Research Centre, Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH, UK
| | - Giuseppe Lazzarino
- Department of Biomedical and Biotechnological Sciences, Division of Medical Biochemistry, University of Catania, Via S. Sofia 97, 95123 Catania, Italy
| | - Angela Maria Amorini
- Department of Biomedical and Biotechnological Sciences, Division of Medical Biochemistry, University of Catania, Via S. Sofia 97, 95123 Catania, Italy
| |
Collapse
|
5
|
Arroum T, Borowski MT, Marx N, Schmelter F, Scholz M, Psathaki OE, Hippler M, Enriquez JA, Busch KB. Loss of respiratory complex I subunit NDUFB10 affects complex I assembly and supercomplex formation. Biol Chem 2023; 404:399-415. [PMID: 36952351 DOI: 10.1515/hsz-2022-0309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 03/06/2023] [Indexed: 03/24/2023]
Abstract
The orchestrated activity of the mitochondrial respiratory or electron transport chain (ETC) and ATP synthase convert reduction power (NADH, FADH2) into ATP, the cell's energy currency in a process named oxidative phosphorylation (OXPHOS). Three out of the four ETC complexes are found in supramolecular assemblies: complex I, III, and IV form the respiratory supercomplexes (SC). The plasticity model suggests that SC formation is a form of adaptation to changing conditions such as energy supply, redox state, and stress. Complex I, the NADH-dehydrogenase, is part of the largest supercomplex (CI + CIII2 + CIVn). Here, we demonstrate the role of NDUFB10, a subunit of the membrane arm of complex I, in complex I and supercomplex assembly on the one hand and bioenergetics function on the other. NDUFB10 knockout was correlated with a decrease of SCAF1, a supercomplex assembly factor, and a reduction of respiration and mitochondrial membrane potential. This likely is due to loss of proton pumping since the CI P P -module is downregulated and the P D -module is completely abolished in NDUFB10 knock outs.
Collapse
Affiliation(s)
- Tasnim Arroum
- Institute of Integrative Cell Biology and Physiology, Bioenergetics and Mitochondrial Dynamics Section, University of Münster, Schloßplatz 5, D-49078 Münster, Germany
| | - Marie-Theres Borowski
- Institute of Integrative Cell Biology and Physiology, Bioenergetics and Mitochondrial Dynamics Section, University of Münster, Schloßplatz 5, D-49078 Münster, Germany
| | - Nico Marx
- Institute of Integrative Cell Biology and Physiology, Bioenergetics and Mitochondrial Dynamics Section, University of Münster, Schloßplatz 5, D-49078 Münster, Germany
| | - Frank Schmelter
- Institute of Integrative Cell Biology and Physiology, Bioenergetics and Mitochondrial Dynamics Section, University of Münster, Schloßplatz 5, D-49078 Münster, Germany
| | - Martin Scholz
- Institute of Plant Biotechnology, University of Münster, Schloßplatz 5, D-49078 Münster, Germany
| | - Olympia Ekaterini Psathaki
- Center of Cellular Nanoanalytics, Integrated Bioimaging Facility, University of Osnabrück, Barbarastr. 11, D-49076 Osnabrück, Germany
| | - Michael Hippler
- Institute of Plant Biotechnology, University of Münster, Schloßplatz 5, D-49078 Münster, Germany
| | - José Antonio Enriquez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, E-28029 Madrid, Spain
- Centro de Investigaciones Biomédicas en Red en Fraglidad y Envejecimiento Saludable (CIBERFES), Av. Monforte de Lemos, 3-5, Pabellón 11, Planta 0, E-28029 Madrid, Spain
| | - Karin B Busch
- Institute of Integrative Cell Biology and Physiology, Bioenergetics and Mitochondrial Dynamics Section, University of Münster, Schloßplatz 5, D-49078 Münster, Germany
| |
Collapse
|
6
|
Walkon LL, Strubbe-Rivera JO, Bazil JN. Calcium Overload and Mitochondrial Metabolism. Biomolecules 2022; 12:biom12121891. [PMID: 36551319 PMCID: PMC9775684 DOI: 10.3390/biom12121891] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 11/30/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Mitochondria calcium is a double-edged sword. While low levels of calcium are essential to maintain optimal rates of ATP production, extreme levels of calcium overcoming the mitochondrial calcium retention capacity leads to loss of mitochondrial function. In moderate amounts, however, ATP synthesis rates are inhibited in a calcium-titratable manner. While the consequences of extreme calcium overload are well-known, the effects on mitochondrial function in the moderately loaded range remain enigmatic. These observations are associated with changes in the mitochondria ultrastructure and cristae network. The present mini review/perspective follows up on previous studies using well-established cryo-electron microscopy and poses an explanation for the observable depressed ATP synthesis rates in mitochondria during calcium-overloaded states. The results presented herein suggest that the inhibition of oxidative phosphorylation is not caused by a direct decoupling of energy metabolism via the opening of a calcium-sensitive, proteinaceous pore but rather a separate but related calcium-dependent phenomenon. Such inhibition during calcium-overloaded states points towards mitochondrial ultrastructural modifications, enzyme activity changes, or an interplay between both events.
Collapse
Affiliation(s)
- Lauren L. Walkon
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Jasiel O. Strubbe-Rivera
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
- Correspondence:
| | - Jason N. Bazil
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| |
Collapse
|
7
|
Yang H, Wu J, Zhen S, Hu Y, Li D, Xie M, Zhu H. Proteomic analysis of spinal cord tissue in a rat model of cancer-induced bone pain. Front Mol Neurosci 2022; 15:1009615. [PMID: 36545122 PMCID: PMC9760935 DOI: 10.3389/fnmol.2022.1009615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 11/16/2022] [Indexed: 12/12/2022] Open
Abstract
Background Cancer-induced bone pain (CIBP) is a moderate to severe pain and seriously affects patients' quality of life. Spinal cord plays critical roles in pain generation and maintenance. Identifying differentially expressed proteins (DEPs) in spinal cord is essential to elucidate the mechanisms of cancer pain. Methods CIBP rat model was established by the intratibial inoculation of MRMT-1 cells. Positron emission tomography (PET) scan and transmission electron microscopy (TEM) were used to measure the stats of spinal cord in rats. Label free Liquid Chromatography with tandem mass spectrometry (LC-MS-MS) were used to analyze the whole proteins from the lumbar spinal cord. Differentially expressed proteins (DEPs) were performed using Gene Ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis, and verified using Western blot and immunofluorescence assay. Results In the current study, CIBP rats exhibited bone damage, spontaneous pain, mechanical hyperalgesia, and impaired motor ability. In spinal cord, an hypermetabolism and functional abnormality were revealed on CIBP rats. An increase of synaptic vesicles density in active zone and a disruption of mitochondrial structure in spinal cord of CIBP rats were observed. Meanwhile, 422 DEPs, consisting of 167 up-regulated and 255 down-regulated proteins, were identified among total 1539 proteins. GO enrichment analysis indicated that the DEPs were mainly involved in catabolic process, synaptic function, and enzymic activity. KEGG pathway enrichment analysis indicated a series of pathways, including nervous system disease, hormonal signaling pathways and amino acid metabolism, were involved. Expression change of synaptic and mitochondrial related protein, such as complexin 1 (CPLX1), synaptosomal-associated protein 25 (SNAP25), synaptotagmin 1 (SYT1), aldehyde dehydrogenase isoform 1B1 (ALDH1B1), Glycine amidinotransferase (GATM) and NADH:ubiquinone oxidoreductase subunit A11 (NDUFA11), were further validated using immunofluorescence and Western blot analysis. Conclusion This study provides valuable information for understanding the mechanisms of CIBP, and supplies potential therapeutic targets for cancer pain.
Collapse
Affiliation(s)
- Heyu Yang
- Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Ji Wu
- Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China
| | - Shuqing Zhen
- Matang Hospital of Traditional Chinese Medicine, Xianning, China
| | - Yindi Hu
- Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Dai Li
- Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Min Xie
- Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Haili Zhu
- Xianning Medical College, Hubei University of Science and Technology, Xianning, China,*Correspondence: Haili Zhu,
| |
Collapse
|
8
|
Xiao J, Wang WX. Patterns and Crucial Regulation of Alternative Splicing During Early Development in Zebrafish. J Mol Biol 2022; 434:167821. [PMID: 36087778 DOI: 10.1016/j.jmb.2022.167821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 08/30/2022] [Accepted: 08/30/2022] [Indexed: 10/31/2022]
Abstract
Many vertebrate genes generate multiple transcript variants that may encode functionally distinct protein isoforms, but the transcriptomes of various developmental stages are poorly defined. Identifying the transcriptome and its regulation during the normal developmental process is the key to deciphering the developmental stage-specific functions of genes. Here we presented a systematic assessment of the temporal alternative splicing (AS) events during the critical development stages to capture the dynamic gene expression changes and AS in zebrafish. An unexpected transcriptome complexity generated by AS was observed during zebrafish development. The patterns of AS events varied substantially among developmental stages despite the similarities in the total proportion of AS genes. We further found that AS afforded substantial functional diversification of genes through the generation of stage-specific AS events from broadly protein-coding genes as an essential developmental regulatory mechanism. Skipped exon (SE) showed the strongest signals among developmental AS (devAS), suggesting that devAS events generated by SE may be necessary for the normal development of zebrafish. Most developmental genes regulated by AS mechanisms were not modulated in terms of their overall expression levels, indicating that AS shaped the transcriptome independently from transcriptional regulation during development. 128-cell stage was a critical stage for gene transcription during embryonic development. Splicing factors as an essential developmental regulator underwent AS in the potential autoregulatory feedback loop and expressed multiple isoforms. Thus, zebrafish development was shaped by an interplay of programs controlling gene expression levels and AS. Overall, we provided a global view of developmental patterns of AS during zebrafish development and revealed that AS transitions were the crucial regulatory component of zebrafish embryonic development.
Collapse
Affiliation(s)
- Jie Xiao
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China
| | - Wen-Xiong Wang
- School of Energy and Environment and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China; Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China.
| |
Collapse
|
9
|
Ischemic Preconditioning and Postconditioning Protect the Heart by Preserving the Mitochondrial Network. BIOMED RESEARCH INTERNATIONAL 2022; 2022:6889278. [PMID: 36203484 PMCID: PMC9532115 DOI: 10.1155/2022/6889278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 09/06/2022] [Indexed: 12/02/2022]
Abstract
Background Mitochondria fuse to form elongated networks which are more tolerable to stress and injury. Ischemic pre- and postconditioning (IPC and IPost, respectively) are established cardioprotective strategies in the preclinical setting. Whether IPC and IPost modulates mitochondrial morphology is unknown. We hypothesize that the protective effects of IPC and IPost may be conferred via preservation of mitochondrial network. Methods IPC and IPost were applied to the H9c2 rat myoblast cells, isolated adult primary murine cardiomyocytes, and the Langendorff-isolated perfused rat hearts. The effects of IPC and IPost on cardiac cell death following ischemia-reperfusion injury (IRI), mitochondrial morphology, and gene expression of mitochondrial-shaping proteins were investigated. Results IPC and IPost successfully reduced cardiac cell death and myocardial infarct size. IPC and IPost maintained the mitochondrial network in both H9c2 and isolated adult primary murine cardiomyocytes. 2D-length measurement of the 3 mitochondrial subpopulations showed that IPC and IPost significantly increased the length of interfibrillar mitochondria (IFM). Gene expression of the pro-fusion protein, Mfn1, was significantly increased by IPC, while the pro-fission protein, Drp1, was significantly reduced by IPost in the H9c2 cells. In the primary cardiomyocytes, gene expression of both Mfn1 and Mfn2 were significantly upregulated by IPC and IPost, while Drp1 was significantly downregulated by IPost. In the Langendorff-isolated perfused heart, gene expression of Drp1 was significantly downregulated by both IPC and IPost. Conclusion IPC and IPost-mediated upregulation of pro-fusion proteins (Mfn1 and Mfn2) and downregulation of pro-fission (Drp1) promote maintenance of the interconnected mitochondrial network, ultimately conferring cardioprotection against IRI.
Collapse
|
10
|
PGC-1β maintains mitochondrial metabolism and restrains inflammatory gene expression. Sci Rep 2022; 12:16028. [PMID: 36163487 PMCID: PMC9512823 DOI: 10.1038/s41598-022-20215-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 09/09/2022] [Indexed: 11/08/2022] Open
Abstract
Metabolic programming of the innate immune cells known as dendritic cells (DCs) changes in response to different stimuli, influencing their function. While the mechanisms behind increased glycolytic metabolism in response to inflammatory stimuli are well-studied, less is known about the programming of mitochondrial metabolism in DCs. We used lipopolysaccharide (LPS) and interferon-β (IFN-β), which differentially stimulate the use of glycolysis and oxidative phosphorylation (OXPHOS), respectively, to identify factors important for mitochondrial metabolism. We found that the expression of peroxisome proliferator-activated receptor gamma co-activator 1β (PGC-1β), a transcriptional co-activator and known regulator of mitochondrial metabolism, decreases when DCs are activated with LPS, when OXPHOS is diminished, but not with IFN-β, when OXPHOS is maintained. We examined the role of PGC-1β in bioenergetic metabolism of DCs and found that PGC-1β deficiency indeed impairs their mitochondrial respiration. PGC-1β-deficient DCs are more glycolytic compared to controls, likely to compensate for reduced OXPHOS. PGC-1β deficiency also causes decreased capacity for ATP production at steady state and in response to IFN-β treatment. Loss of PGC-1β in DCs leads to increased expression of genes in inflammatory pathways, and reduced expression of genes encoding proteins important for mitochondrial metabolism and function. Collectively, these results demonstrate that PGC-1β is a key regulator of mitochondrial metabolism and negative regulator of inflammatory gene expression in DCs.
Collapse
|
11
|
Germline mutations in mitochondrial complex I reveal genetic and targetable vulnerability in IDH1-mutant acute myeloid leukaemia. Nat Commun 2022; 13:2614. [PMID: 35551192 PMCID: PMC9098909 DOI: 10.1038/s41467-022-30223-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 04/20/2022] [Indexed: 11/13/2022] Open
Abstract
The interaction of germline variation and somatic cancer driver mutations is under-investigated. Here we describe the genomic mitochondrial landscape in adult acute myeloid leukaemia (AML) and show that rare variants affecting the nuclear- and mitochondrially-encoded complex I genes show near-mutual exclusivity with somatic driver mutations affecting isocitrate dehydrogenase 1 (IDH1), but not IDH2 suggesting a unique epistatic relationship. Whereas AML cells with rare complex I variants or mutations in IDH1 or IDH2 all display attenuated mitochondrial respiration, heightened sensitivity to complex I inhibitors including the clinical-grade inhibitor, IACS-010759, is observed only for IDH1-mutant AML. Furthermore, IDH1 mutant blasts that are resistant to the IDH1-mutant inhibitor, ivosidenib, retain sensitivity to complex I inhibition. We propose that the IDH1 mutation limits the flexibility for citrate utilization in the presence of impaired complex I activity to a degree that is not apparent in IDH2 mutant cells, exposing a mutation-specific metabolic vulnerability. This reduced metabolic plasticity explains the epistatic relationship between the germline complex I variants and oncogenic IDH1 mutation underscoring the utility of genomic data in revealing metabolic vulnerabilities with implications for therapy. Mitochondrial metabolism has been associated with tumourigenesis in acute myeloid leukaemia (AML) and currently considered as a potential therapeutic target. Here, the authors show, in patients with AML, that germline mutations in mitochondrial complex I are mutually exclusive with somatic mutations in the metabolic enzyme IDH1, and find IDH1 mutant cells have increased sensitivity to complex I inhibitors.
Collapse
|
12
|
First person – Amber Knapp-Wilson. J Cell Sci 2021. [DOI: 10.1242/jcs.259059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ABSTRACT
First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Amber Knapp-Wilson is co-first author on ‘Maintenance of complex I and its supercomplexes by NDUF-11 is essential for mitochondrial structure, function and health’, published in JCS. Amber conducted the research described in this article while a PhD student in the labs of Professor Ian Collinson and Professor Patricia Kuwabara at the University of Bristol, UK. She is now a medical student and part-time research associate in the lab of Professor Andrew Mumford at the University of Bristol, investigating the impact of pathogenic genetic variants on protein biochemistry and function.
Collapse
|