bims-midhyp Biomed News
on Mitochondrial dysfunction and hypoxia
Issue of 2023–08–06
eleven papers selected by
Alia Ablieh, Universität Heidelberg
  1. [Protective effect and mechanism of AKAP1 on myocardial injury induced by highland hypobaric hypoxia].
  2. Metabolic switch from fatty acid oxidation to glycolysis in knock-in mouse model of Barth syndrome.
  3. Mitochondrial modulation of amplified preconditioning influences of remote ischemia plus erythropoietin against skeletal muscle ischemia/reperfusion injury in rats.
  4. The bridge between cell survival and cell death: reactive oxygen species-mediated cellular stress.
  5. Mitochondrial quality control in hepatic ischemia-reperfusion injury.
  6. Mitochondrial epigenetics in aging and cardiovascular diseases.
  7. Alternative splicing of CEACAM1 by hypoxia-inducible factor-1α enhances tolerance to hepatic ischemia in mice and humans.
  8. Restoration of energy homeostasis under oxidative stress: Duo synergistic AMPK pathways regulating arginine kinases.
  9. Structural and functional complexity of HSP90 in cellular homeostasis and disease.
  10. The Role of Mitochondrial Biogenesis in Ischemic Stroke.
  11. A Novel Heat Shock Protein 70-Based Vaccine Prepared from DC Tumor Fusion Cells: An Update.
  1. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi. 2023 Jul 20. 41(7): 486-496
    [Protective effect and mechanism of AKAP1 on myocardial injury induced by highland hypobaric hypoxia].
    X D Shi, L Cao, R Tan, S Q Zhou, F Li, F Z Liu.
      Objective: To investigate the protective effect and its possible mechanism of A-kinase anchored protein 1 (AKAP1) on the myocardial injury induced by highland hypobaric hypoxia. Methods: From January 2021 to May 2022, male C57BL/6 SPF grade mice were divided into wild type control (WT) group and highland hypobaric hypoxia (HH) group with 6 mice in each group. HH group simulated 6000 m altitude with low pressure oxygen chamber for 4 weeks to build the model. Primary myocardial cells of SD rats were divided into normoxia control group and hypoxia experimental group (n=3). Cell models were constructed in a three-gas hypoxia incubator with 1% oxygen concentration for 24 h. AKAP1 protein and mRNA expression in myocardial tissue and cells were detected by western blotting, immunohistochemistry and quantitative real-time polymerase chain reaction (qPCR). After myocardial point injection of the AKAP1 or the control adenovirus, the mice were divided into 3 groups (n=6) : WT group, highland hypobaric hypoxia overexpression control group (HH+Ad-Ctrl group) and highland hypobaric hypoxia overexpression experimental group (HH+Ad-AKAP1 group). The cardiac function of mice was detected by noninvasive M-type ultrasonic cardiomotive, myocardial fibrosis was detected by Masson and Sirius Red staining, and cardiomyocyte hypertrophy was detected by wheat germ agglutinin. After the expression of AKAP1 in primary cardiomyocytes was downregulated by siRNA and upregulated by adenovirus, the cells were divided into three groups (n=3) : normoxia control group, hypoxia interference control group (hypoxia+siCtrl group), hypoxia AKAP1 knockdown group (hypoxia+siAKAP1 group) ; normoxia control group, hypoxia overexpression control group (hypoxia+Ad-Ctrl group), hypoxia AKAP1 overexpression group (hypoxia+Ad-AKAP1 group). Apoptosis was detected by flow cytometry, AKAP1, apoptosis-related protein and mRNA expression levels were detected by western blotting and qPCR, mitochondrial membrane potential was detected by JC-1 staining, and mitochondrial reactive oxygen specie (ROS) level was detected by MitoSOX. Results: The expression of AKAP1 in cardiac muscle of HH group was lower than that in the WT group, and the expression of AKAP1 in hypoxia experimental group was lower than that in normoxia control group (P<0.01). Compared with WT group, the left ventricular ejection fraction and fraction shortening of left ventricle in HH+Ad-Ctrl group were decreased (P<0.01), myocardial fibrosis and hypertrophy were aggravated (P<0.01), and the expression of B-cell lymphoma-2 (BCL-2) was decreased, the expressions of BCL-2-associated X protein (BAX), Caspase 3 and Caspase 9 were increased (P<0.01). After AKAP1 overexpression, compared with HH+Ad-Ctrl group, the left ventricular ejection fraction and left ventricular fraction shortening were increased in HH+Ad-AKAP1 group (P<0.01), myocardial fibrosis and hypertrophy were reduced (P<0.01), and the expression of BCL-2 was increased, the expressions of BAX, Caspase 3 and Caspase 9 were decreased (P<0.01). Compared with normoxia control group, the expression of BCL-2 in hypoxia+siCtrl group was decreased, the expressions of BAX, Caspase 3, Caspase 9 were increased, the apoptosis level was increased (P<0.01), the mitochondrial membrane potential was decreased and the production of ROS was increased (P<0.01). After AKAP1 knockdown, compared with hypoxia+siCtrl group, the expression of BCL-2 in hypoxia+siAKAP1 group was decreased, the expressions of BAX, Caspase 3, Caspase 9 were increased, the apoptosis level was increased (P<0.01), mitochondrial membrane potential was decreased, and the production of ROS was increased (P<0.01). After AKAP1 overexpression, compared with hypoxia+Ad-Ctrl group, the expression of BCL-2 in hypoxia+Ad-AKAP1 group was increased, the expressions of BAX, Caspase 3 and Caspase 9 were decreased (P<0.05), the apoptosis level was decreased (P<0.01), and the mitochondrial membrane potential was enhanced, and the production of ROS was decreased (P<0.01) . Conclusion: The downregulation of AKAP1 in cardiomyocytes under highland hypobaric hypoxia may lead to the decrease of mitochondrial membrane potential and the increase of ROS generation, leading to the apoptosis of cardiomyocytes, and thus aggravating the myocardial injury at highland hypobaric hypoxia.
    Keywords:  A-kinase anchored protein 1, AKAP1; Highland hypoxia; Hypobaric; Mice; Mitochondrial dysfunction; Myocardial injury; Rats
    DOI:  https://doi.org/10.3760/cma.j.cn121094-20221025-00513
  2. EMBO Mol Med. 2023 Aug 03. e17399
    Metabolic switch from fatty acid oxidation to glycolysis in knock-in mouse model of Barth syndrome.
    Arpita Chowdhury, Angela Boshnakovska, Abhishek Aich, Aditi Methi, Ana Maria Vergel Leon, Ivan Silbern, Christian Lüchtenborg, Lukas Cyganek, Jan Prochazka, Radislav Sedlacek, Jiri Lindovsky, Dominic Wachs, Zuzana Nichtova, Dagmar Zudova, Gizela Koubkova, André Fischer, Henning Urlaub, Britta Brügger, Dörthe M Katschinski, Jan Dudek, Peter Rehling.
      Mitochondria are central for cellular metabolism and energy supply. Barth syndrome (BTHS) is a severe disorder, due to dysfunction of the mitochondrial cardiolipin acyl transferase tafazzin. Altered cardiolipin remodeling affects mitochondrial inner membrane organization and function of membrane proteins such as transporters and the oxidative phosphorylation (OXPHOS) system. Here, we describe a mouse model that carries a G197V exchange in tafazzin, corresponding to BTHS patients. TAZG197V mice recapitulate disease-specific pathology including cardiac dysfunction and reduced oxidative phosphorylation. We show that mutant mitochondria display defective fatty acid-driven oxidative phosphorylation due to reduced levels of carnitine palmitoyl transferases. A metabolic switch in ATP production from OXPHOS to glycolysis is apparent in mouse heart and patient iPSC cell-derived cardiomyocytes. An increase in glycolytic ATP production inactivates AMPK causing altered metabolic signaling in TAZG197V . Treatment of mutant cells with AMPK activator reestablishes fatty acid-driven OXPHOS and protects mice against cardiac dysfunction.
    Keywords:  Barth syndrome; cardiolipin; cardiomyopathy; mitochondria; tafazzin
    DOI:  https://doi.org/10.15252/emmm.202317399
  3. Life Sci. 2023 Jul 27. pii: S0024-3205(23)00614-8. [Epub ahead of print]329 121979
    Mitochondrial modulation of amplified preconditioning influences of remote ischemia plus erythropoietin against skeletal muscle ischemia/reperfusion injury in rats.
    Asmaa A Khalifa, Mennatallah A Ali, Nahed H Elsokkary, Samar S Elblehi, Mahmoud M El-Mas.
       AIMS: Skeletal muscle ischemia and reperfusion (S-I/R) injury is relieved by interventions like remote ischemic preconditioning (RIPC). Here, we tested the hypothesis that simultaneous exposure to a minimal dose of erythropoietin (EPO) boosts the protection conferred by RIPC against S-I/R injury and concomitant mitochondrial oxidative and apoptotic defects.
    MAIN METHODS: S-I/R injury was induced in rats by 3-h right hindlimb ischemia followed by 3-h of reperfusion, whereas RIPC involved 3 brief consecutive I/R cycles of the contralateral hindlimb.
    KEY FINDINGS: S-I/R injury caused (i) rises in serum lactate dehydrogenase and creatine kinase and falls in serum pyruvate, (ii) structural deformities like sarcoplasm vacuolations, segmental necrosis, and inflammatory cells infiltration, and (iii) decreased amplitude and increased duration of electromyography action potentials. These defects were partially ameliorated by RIPC and dose-dependently by EPO (500 or 5000 IU/kg). Further, greater repairs of S-I/R-evoked damages were seen after prior exposure to the combined RIPC/EPO-500 intervention. The latter also caused more effective (i) preservation of mitochondrial number (confocal microscopy assessed Mitotracker red staining) and function (citrate synthase activity), (ii) suppression of mitochondrial DNA damage and indices of oxidative stress and apoptosis (succinate dehydrogenase, myeloperoxidase, cardiolipin, and cytochrome c), (iii) preventing calcium and nitric oxide metabolites (NOx) accumulation and glycogen consumption, and (iv) upregulating EPO receptors (EPO-R) gene expression.
    SIGNIFICANCE: dual RIPC/EPO conditioning exceptionally mends structural, functional, and neuronal deficits caused by I/R injury and interrelated mitochondrial oxidative and apoptotic damage. Clinically, the utilization of relatively low EPO doses could minimize the hormone-related adverse effects.
    Keywords:  Erythropoietin; Gastrocnemius muscle; Ischemia-reperfusion injury; Mitochondria; Remote preconditioning
    DOI:  https://doi.org/10.1016/j.lfs.2023.121979
  4. EXCLI J. 2023 ;22 520-555
    The bridge between cell survival and cell death: reactive oxygen species-mediated cellular stress.
    Nese Vardar Acar, Riza Köksal Özgül.
      As a requirement of aerobic metabolism, regulation of redox homeostasis is indispensable for the continuity of living homeostasis and life. Since the stability of the redox state is necessary for the maintenance of the biological functions of the cells, the balance between the pro-oxidants, especially ROS and the antioxidant capacity is kept in balance in the cells through antioxidant defense systems. The pleiotropic transcription factor, Nrf2, is the master regulator of the antioxidant defense system. Disruption of redox homeostasis leads to oxidative and reductive stress, bringing about multiple pathophysiological conditions. Oxidative stress characterized by high ROS levels causes oxidative damage to biomolecules and cell death, while reductive stress characterized by low ROS levels disrupt physiological cell functions. The fact that ROS, which were initially attributed as harmful products of aerobic metabolism, at the same time function as signal molecules at non-toxic levels and play a role in the adaptive response called mithormesis points out that ROS have a dose-dependent effect on cell fate determination. See also Figure 1(Fig. 1).
    Keywords:  Nrf2; antioxidant defense systems; cell death pathways; mitohormesis; oxidative and reductive stress; redox homeostasis
    DOI:  https://doi.org/10.17179/excli2023-6221
  5. Heliyon. 2023 Jul;9(7): e17702
    Mitochondrial quality control in hepatic ischemia-reperfusion injury.
    LiuSong Wang, Zan Jie Feng, Xuan Ma, Kai Li, Xin Yao Li, Yi Tang, Cijun Peng.
      Hepatic ischemia-reperfusion injury is a phenomenon in which exacerbating damage of liver cells due to restoration of blood flow following ischemia during liver surgery, especially those involving liver transplantation. Mitochondria, the energy-producing organelles, are crucial for cell survival and apoptosis and have evolved a range of quality control mechanisms to maintain homeostasis in the mitochondrial network in response to various stress conditions. Hepatic ischemia-reperfusion leads to disruption of mitochondrial quality control mechanisms, as evidenced by reduced mitochondrial autophagy, excessive division, reduced fusion, and inhibition of biogenesis. This leads to dysfunction of the mitochondrial network. The accumulation of damaged mitochondria ultimately results in apoptosis of hepatocytes due to the release of apoptotic proteins like cytochrome C. This worsens hepatic ischemia-reperfusion injury. Currently, hepatic ischemia-reperfusion injury protection is being studied using different approaches such as drug pretreatment, stem cells and exosomes, genetic interventions, and mechanical reperfusion, all aimed at targeting mitochondrial quality control mechanisms. This paper aims to provide direction for future research on combating HIRI by reviewing the latest studies that focus on targeting mitochondrial quality control mechanisms.
    Keywords:  Hepatic ischemia-reperfusion injury; Mitochondrial biogenesis; Mitochondrial dynamics; Mitochondrial quality control mechanisms; Mitophagy
    DOI:  https://doi.org/10.1016/j.heliyon.2023.e17702
  6. Front Cardiovasc Med. 2023 ;10 1204483
    Mitochondrial epigenetics in aging and cardiovascular diseases.
    Alessia Mongelli, Alessandro Mengozzi, Martin Geiger, Era Gorica, Shafeeq Ahmed Mohammed, Francesco Paneni, Frank Ruschitzka, Sarah Costantino.
      Mitochondria are cellular organelles which generate adenosine triphosphate (ATP) molecules for the maintenance of cellular energy through the oxidative phosphorylation. They also regulate a variety of cellular processes including apoptosis and metabolism. Of interest, the inner part of mitochondria-the mitochondrial matrix-contains a circular molecule of DNA (mtDNA) characterised by its own transcriptional machinery. As with genomic DNA, mtDNA may also undergo nucleotide mutations that have been shown to be responsible for mitochondrial dysfunction. During physiological aging, the mitochondrial membrane potential declines and associates with enhanced mitophagy to avoid the accumulation of damaged organelles. Moreover, if the dysfunctional mitochondria are not properly cleared, this could lead to cellular dysfunction and subsequent development of several comorbidities such as cardiovascular diseases (CVDs), diabetes, respiratory and cardiovascular diseases as well as inflammatory disorders and psychiatric diseases. As reported for genomic DNA, mtDNA is also amenable to chemical modifications, namely DNA methylation. Changes in mtDNA methylation have shown to be associated with altered transcriptional programs and mitochondrial dysfunction during aging. In addition, other epigenetic signals have been observed in mitochondria, in particular the interaction between mtDNA methylation and non-coding RNAs. Mitoepigenetic modifications are also involved in the pathogenesis of CVDs where oxygen chain disruption, mitochondrial fission, and ROS formation alter cardiac energy metabolism leading to hypertrophy, hypertension, heart failure and ischemia/reperfusion injury. In the present review, we summarize current evidence on the growing importance of epigenetic changes as modulator of mitochondrial function in aging. A better understanding of the mitochondrial epigenetic landscape may pave the way for personalized therapies to prevent age-related diseases.
    Keywords:  aging; cardiovascular diseases; methylation; mitochondria; mitoepigenetics; mtDNA; ncRNAs
    DOI:  https://doi.org/10.3389/fcvm.2023.1204483
  7. Sci Transl Med. 2023 08 02. 15(707): eadf2059
    Alternative splicing of CEACAM1 by hypoxia-inducible factor-1α enhances tolerance to hepatic ischemia in mice and humans.
    Kenneth J Dery, Hidenobu Kojima, Shoichi Kageyama, Kentaro Kadono, Hirofumi Hirao, Brian Cheng, Yuan Zhai, Douglas G Farmer, Fady M Kaldas, Xiaoyi Yuan, Holger K Eltzschig, Jerzy W Kupiec-Weglinski.
      Although alternative splicing (AS) drives transcriptional responses and cellular adaptation to environmental stresses, its contributions in organ transplantation have not been appreciated. We have shown that carcinoembryonic antigen-related cell adhesion molecule (Ceacam1; CD66a), a transmembrane biliary glycoprotein expressed in epithelial, endothelial, and immune cells, determines donor liver transplant quality. Here, we studied how AS of Ceacam1 affects ischemia-reperfusion injury (IRI) in mouse and human livers. We found that the short cytoplasmic isoform Ceacam1-S increased during early acute and late resolution phases of warm IRI injury in mice. Transfection of Ceacam1-deficient mouse hepatocytes with adenoviral Ceacam1-S mitigated hypoxia-induced loss of cellular adhesion by repressing the Ask1/p-p38 cell death pathway. Nucleic acid-blocking morpholinos, designed to selectively induce Ceacam1-S, protected hepatocyte cultures against temperature-induced stress in vitro. Luciferase and chromatin immunoprecipitation assays identified direct binding of hypoxia-inducible factor-1α (Hif-1α) to the mouse polypyrimidine tract binding protein 1 (Ptbp1) promoter region. Dimethyloxalylglycine protected mouse livers from warm IR stress and hepatocellular damage by inhibiting prolyl hydroxylase domain-containing protein 1 and promoting AS of Ceacam1-S. Last, analysis of 46 human donor liver grafts revealed that CEACAM1-S positively correlated with pretransplant HIF1A expression. This also correlated with better transplant outcomes, including reduced TIMP1, total bilirubin, proinflammatory MCP1, CXCL10 cytokines, immune activation markers IL17A, and incidence of delayed complications from biliary anastomosis. This translational study identified mouse Hif-1α-controlled AS of Ceacam1, through transcriptional regulation of Ptbp1 promoter region, as a functional underpinning of hepatoprotection against IR stress and tissue damage in liver transplantation.
    DOI:  https://doi.org/10.1126/scitranslmed.adf2059
  8. PLoS Genet. 2023 Aug 03. 19(8): e1010843
    Restoration of energy homeostasis under oxidative stress: Duo synergistic AMPK pathways regulating arginine kinases.
    Nan Zhang, Xiangkun Meng, Heng Jiang, Huichen Ge, Kun Qian, Yang Zheng, Yoonseong Park, Jianjun Wang.
      Rapid depletion of cellular ATP can occur by oxidative stress induced by reactive oxygen species (ROS). Maintaining energy homeostasis requires the key molecular components AMP-activated protein kinase (AMPK) and arginine kinase (AK), an invertebrate orthologue of the mammalian creatine kinase (CK). Here, we deciphered two independent and synergistic pathways of AMPK acting on AK by using the beetle Tribolium castaneum as a model system. First, AMPK acts on transcriptional factor forkhead box O (FOXO) leading to phosphorylation and nuclear translocation of the FOXO. The phospho-FOXO directly promotes the expression of AK upon oxidative stress. Concomitantly, AMPK directly phosphorylates the AK to switch the direction of enzymatic catalysis for rapid production of ATP from the phosphoarginine-arginine pool. Further in vitro assays revealed that Sf9 cells expressing phospho-deficient AK mutants displayed the lower ATP/ADP ratio and cell viability under paraquat-induced oxidative stress conditions when compared with Sf9 cells expressing wild-type AKs. Additionally, the AMPK-FOXO-CK pathway is also involved in the restoration of ATP homeostasis under oxidative stress in mammalian HEK293 cells. Overall, we provide evidence that two distinct AMPK-AK pathways, transcriptional and post-translational regulations, are coherent responders to acute oxidative stresses and distinguished from classical AMPK-mediated long-term metabolic adaptations to energy challenge.
    DOI:  https://doi.org/10.1371/journal.pgen.1010843
  9. Nat Rev Mol Cell Biol. 2023 Jul 31.
    Structural and functional complexity of HSP90 in cellular homeostasis and disease.
    Gabriela Chiosis, Chander S Digwal, Jane B Trepel, Len Neckers.
      Heat shock protein 90 (HSP90) is a chaperone with vital roles in regulating proteostasis, long recognized for its function in protein folding and maturation. A view is emerging that identifies HSP90 not as one protein that is structurally and functionally homogeneous but, rather, as a protein that is shaped by its environment. In this Review, we discuss evidence of multiple structural forms of HSP90 in health and disease, including homo-oligomers and hetero-oligomers, also termed epichaperomes, and examine the impact of stress, post-translational modifications and co-chaperones on their formation. We describe how these variations influence context-dependent functions of HSP90 as well as its interaction with other chaperones, co-chaperones and proteins, and how this structural complexity of HSP90 impacts and is impacted by its interaction with small molecule modulators. We close by discussing recent developments regarding the use of HSP90 inhibitors in cancer and how our new appreciation of the structural and functional heterogeneity of HSP90 invites a re-evaluation of how we discover and implement HSP90 therapeutics for disease treatment.
    DOI:  https://doi.org/10.1038/s41580-023-00640-9
  10. J Integr Neurosci. 2023 Jul 05. 22(4): 88
    The Role of Mitochondrial Biogenesis in Ischemic Stroke.
    Behrouz Shademan, Cigir Biray Avci, Vahidreza Karamad, Gholamreza Jahangirzadeh Soureh, Jalhe Bagheri Hamzyan Olia, Farzaneh Esmaily, Alireza Nourazarian, Masoud Nikanfar.
      Ischaemic stroke is a sudden neurological disorder caused by localised cerebral ischaemia and persistent cerebral infarction. Occlusion of large arteries due to atherothrombosis, cerebral embolism (i.e., embolic infarction), no thrombotic occlusion in small, deep cerebral arteries (i.e., lacunar infarction), and stenosis of proximal arteries due to hypotension leading to decreased cerebral blood flow in arterial supply zones are the most common causes of ischemic stroke (i.e., hemodynamic stroke). It is now known that organelles play an important role in various signaling events and cellular functions. The molecular mechanisms of mitochondria are involved in cerebral ischemia by generating and scavenging reactive oxygen species, apoptosis, biogenesis, mitochondrial dynamics, and inflammation are all examples of electron transport chain dysfunction. More knowledge about the involvement of mitochondria in ischemia-induced neuronal death and neuronal protection will contribute to the development of better treatment programs for stroke syndromes such as ischemic stroke.
    Keywords:  electron transport chain; ischemic stroke; mitochondrial biogenesis; neuronal death
    DOI:  https://doi.org/10.31083/j.jin2204088
  11. Methods Mol Biol. 2023 ;2693 209-219
    A Novel Heat Shock Protein 70-Based Vaccine Prepared from DC Tumor Fusion Cells: An Update.
    Desheng Weng, Stuart K Calderwood, Jianlin Gong.
      We have developed an enhanced molecular chaperone-based vaccine through rapid isolation of Hsp70 peptide complexes after the fusion of tumor and dendritic cells (Hsp70.PC-F). In this approach, the tumor antigens are introduced into the antigen-processing machinery of dendritic cells through the cell fusion process, and thus we can obtain antigenic tumor peptides or their intermediates that have been processed by dendritic cells. Our results show that Hsp70.PC-F has increased immunogenicity compared to preparations from tumor cells alone and therefore constitutes an improved formulation of the chaperone protein-based tumor vaccine.
    Keywords:  Cell fusion; Dendritic cells (DC); Extraction of Hsp70 peptide complexes (Hsp70.PC); Heat shock proteins70 (Hsp70); Tumor vaccine
    DOI:  https://doi.org/10.1007/978-1-0716-3342-7_16
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