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Dodge JD, Browder NJ, Pellegrino MW. Mitochondrial recovery by the UPR mt: Insights from C. elegans. Semin Cell Dev Biol 2024; 154:59-68. [PMID: 36792440 DOI: 10.1016/j.semcdb.2023.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 01/31/2023] [Accepted: 02/02/2023] [Indexed: 02/15/2023]
Abstract
Mitochondria are multifaceted organelles, with such functions as the production of cellular energy to the regulation of cell death. However, mitochondria incur various sources of damage from the accumulation of reactive oxygen species and DNA mutations that can impact the protein folding environment and impair their function. Since mitochondrial dysfunction is often associated with reductions in organismal fitness and possibly disease, cells must have safeguards in place to protect mitochondrial function and promote recovery during times of stress. The mitochondrial unfolded protein response (UPRmt) is a transcriptional adaptation that promotes mitochondrial repair to aid in cell survival during stress. While the earlier discoveries into the regulation of the UPRmt stemmed from studies using mammalian cell culture, much of our understanding about this stress response has been bestowed to us by the model organism Caenorhabditis elegans. Indeed, the facile but powerful genetics of this relatively simple nematode has uncovered multiple regulators of the UPRmt, as well as several physiological roles of this stress response. In this review, we will summarize these major advancements originating from studies using C. elegans.
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Affiliation(s)
- Joshua D Dodge
- The University of Texas at Arlington, Department of Biology, Arlington, TX 76019, USA
| | - Nicholas J Browder
- The University of Texas at Arlington, Department of Biology, Arlington, TX 76019, USA
| | - Mark W Pellegrino
- The University of Texas at Arlington, Department of Biology, Arlington, TX 76019, USA.
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Medha, Priyanka, Sharma S, Sharma M. PE_PGRS45 (Rv2615c) protein of Mycobacterium tuberculosis perturbs mitochondria of macrophages. Immunol Cell Biol 2023. [PMID: 37565603 DOI: 10.1111/imcb.12677] [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: 09/13/2022] [Revised: 03/23/2023] [Accepted: 07/19/2023] [Indexed: 08/12/2023]
Abstract
The PE_PGRS proteins have coevolved with the antigenic ESX-V secretory system and are abundant in pathogenic Mycobacterium. Only a few PE_PGRS proteins have been characterized, and research suggests their role in organelle targeting, cell death pathways, calcium (Ca2+ ) homeostasis and disease pathogenesis. The PE_PGRS45 (Rv2615c) protein was predicted to contain mitochondria targeting sequences by in silico evaluation. Therefore, we investigated the targeting of the Rv2615c protein to host mitochondria and its effect on mitochondrial functions. In vitro experiments showed the Rv2615c protein colocalized with the mitochondria and led to morphological mitochondrial perturbations. Recombinant Rv2615c was observed to cause increased levels of intracellular reactive oxygen species and the adenosine diphosphate-to-adenosine triphosphate ratio. The Rv2615c protein also induced mitochondrial membrane depolarization and the generation of mitochondrial superoxide. We observed the release of cytochrome C into the cytoplasm and increased expression of proapoptotic genes Bax and Bim with no significant change in anti-apoptotic Bcl2 in Rv2615c-stimulated THP1 macrophages. Ca2+ is a key signaling molecule in tuberculosis pathogenesis, modulating host cell responses. As reported for other PE_PGRS proteins, Rv2615c also has Ca2+ -binding motifs and thus can modulate calcium homeostasis in the host. We also observed a high level of Ca2+ influx in THP1 macrophages stimulated with Rv2615c. Based on these findings, we suggest that Rv2615c may be an effector protein that could contribute to disease pathogenesis by targeting host mitochondria.
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Affiliation(s)
- Medha
- DSKC BioDiscovery Laboratory, Department of Zoology, Miranda House, University of Delhi, Delhi, India
| | - Priyanka
- DSKC BioDiscovery Laboratory, Department of Zoology, Miranda House, University of Delhi, Delhi, India
| | - Sadhna Sharma
- DSKC BioDiscovery Laboratory, Department of Zoology, Miranda House, University of Delhi, Delhi, India
| | - Monika Sharma
- DSKC BioDiscovery Laboratory, Department of Zoology, Miranda House, University of Delhi, Delhi, India
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Holland RL, Bosi KD, Seeger AY, Blanke SR. Restoration of mitochondrial structure and function within Helicobacter pylori VacA intoxicated cells. ADVANCES IN MICROBIOLOGY 2023; 13:399-419. [PMID: 37654621 PMCID: PMC10470862 DOI: 10.4236/aim.2023.138026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
The Helicobacter pylori vacuolating cytotoxin (VacA) is an intracellular, mitochondrial-targeting exotoxin that rapidly causes mitochondrial dysfunction and fragmentation. Although VacA targeting of mitochondria has been reported to alter overall cellular metabolism, there is little known about the consequences of extended exposure to the toxin. Here, we describe studies to address this gap in knowledge, which have revealed that mitochondrial dysfunction and fragmentation are followed by a time-dependent recovery of mitochondrial structure, mitochondrial transmembrane potential, and cellular ATP levels. Cells exposed to VacA also initially demonstrated a reduction in oxidative phosphorylation, as well as increase in compensatory aerobic glycolysis. These metabolic alterations were reversed in cells with limited toxin exposure, congruent with the recovery of mitochondrial transmembrane potential and the absence of cytochrome c release from the mitochondria. Taken together, these results are consistent with a model that mitochondrial structure and function are restored in VacA-intoxicated cells.
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Affiliation(s)
- Robin L. Holland
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, 61801
| | - Kristopher D. Bosi
- Department of Microbiology, School of Molecular and Cellular Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, 61801
| | - Ami Y. Seeger
- Department of Microbiology, School of Molecular and Cellular Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, 61801
| | - Steven R. Blanke
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, 61801
- Department of Microbiology, School of Molecular and Cellular Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, 61801
- Biomedical and Translational Sciences Department, Carle Illinois College of Medicine, University of Illinois, Urbana, Illinois 61801
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Maurice NM, Sadikot RT. Mitochondrial Dysfunction in Bacterial Infections. Pathogens 2023; 12:1005. [PMID: 37623965 PMCID: PMC10458073 DOI: 10.3390/pathogens12081005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/23/2023] [Accepted: 07/26/2023] [Indexed: 08/26/2023] Open
Abstract
Mitochondria are critical in numerous cellular processes, including energy generation. Bacterial pathogens target host cell mitochondria through various mechanisms to disturb the host response and improve bacterial survival. We review recent advances in the understanding of how bacteria cause mitochondrial dysfunction through perturbations in mitochondrial cell-death pathways, energy production, mitochondrial dynamics, mitochondrial quality control, DNA repair, and the mitochondrial unfolded protein response. We also briefly highlight possible therapeutic approaches aimed at restoring the host mitochondrial function as a novel strategy to enhance the host response to bacterial infection.
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Affiliation(s)
- Nicholas M. Maurice
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
- Atlanta Veterans Affairs Health Care System, Decatur, GA 30033, USA
| | - Ruxana T. Sadikot
- VA Nebraska Western Iowa Health Care System, Omaha, NE 68105, USA
- Division of Pulmonary, Critical Care & Sleep, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Li Y, Yang S, Jin X, Li D, Lu J, Wang X, Wu M. Mitochondria as novel mediators linking gut microbiota to atherosclerosis that is ameliorated by herbal medicine: A review. Front Pharmacol 2023; 14:1082817. [PMID: 36733506 PMCID: PMC9886688 DOI: 10.3389/fphar.2023.1082817] [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: 10/28/2022] [Accepted: 01/06/2023] [Indexed: 01/18/2023] Open
Abstract
Atherosclerosis (AS) is the main cause of cardiovascular disease (CVD) and is characterized by endothelial damage, lipid deposition, and chronic inflammation. Gut microbiota plays an important role in the occurrence and development of AS by regulating host metabolism and immunity. As human mitochondria evolved from primordial bacteria have homologous characteristics, they are attacked by microbial pathogens as target organelles, thus contributing to energy metabolism disorders, oxidative stress, and apoptosis. Therefore, mitochondria may be a key mediator of intestinal microbiota disorders and AS aggravation. Microbial metabolites, such as short-chain fatty acids, trimethylamine, hydrogen sulfide, and bile acids, also affect mitochondrial function, including mtDNA mutation, oxidative stress, and mitophagy, promoting low-grade inflammation. This further damages cellular homeostasis and the balance of innate immunity, aggravating AS. Herbal medicines and their monomers can effectively ameliorate the intestinal flora and their metabolites, improve mitochondrial function, and inhibit atherosclerotic plaques. This review focuses on the interaction between gut microbiota and mitochondria in AS and explores a therapeutic strategy for restoring mitochondrial function and intestinal microbiota disorders using herbal medicines, aiming to provide new insights for the prevention and treatment of AS.
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Affiliation(s)
- Yujuan Li
- Guang’an Men Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Shengjie Yang
- Guang’an Men Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiao Jin
- Guang’an Men Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Dan Li
- Guang’an Men Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jing Lu
- Guang’an Men Hospital, China Academy of Chinese Medical Sciences, Beijing, China,Beijing University of Chinese Medicine, Beijing, China
| | - Xinyue Wang
- Guang’an Men Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Min Wu
- Guang’an Men Hospital, China Academy of Chinese Medical Sciences, Beijing, China,*Correspondence: Min Wu,
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Roxas JL, Ramamurthy S, Cocchi K, Rutins I, Harishankar A, Agellon A, Wilbur JS, Sylejmani G, Vedantam G, Viswanathan V. Enteropathogenic Escherichia coli regulates host-cell mitochondrial morphology. Gut Microbes 2022; 14:2143224. [PMID: 36476073 PMCID: PMC9733699 DOI: 10.1080/19490976.2022.2143224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The diarrheagenic pathogen enteropathogenic Escherichia coli is responsible for significant childhood mortality and morbidity. EPEC and related attaching-and-effacing (A/E) pathogens use a type III secretion system to hierarchically deliver effector proteins into host cells and manipulate epithelial structure and function. Subversion of host mitochondrial biology is a key aspect of A/E pathogen virulence strategy, but the mechanisms remain poorly defined. We demonstrate that the early-secreted effector EspZ and the late-secreted effector EspH have contrasting effects on host mitochondrial structure and function. EspZ interacts with FIS1, a protein that induces mitochondrial fragmentation and mitophagy. Infection of epithelial cells with either wildtype EPEC or an isogenic espZ deletion mutant (ΔespZ) robustly upregulated FIS1 abundance, but a marked increase in mitochondrial fragmentation and mitophagy was seen only in ΔespZ-infected cells. FIS1-depleted cells were protected against ΔespZ-induced fission, and EspZ-expressing transfected epithelial cells were protected against pharmacologically induced mitochondrial fission and membrane potential disruption. Thus, EspZ interacts with FIS1 and blocks mitochondrial fragmentation and mitophagy. In contrast to WT EPEC, ΔespH-infected epithelial cells had minimal FIS1 upregulation and exhibited hyperfused mitochondria. Consistent with the contrasting impacts on organelle shape, mitochondrial membrane potential was preserved in ΔespH-infected cells, but profoundly disrupted in ΔespZ-infected cells. Collectively, our studies reveal hitherto unappreciated roles for two essential EPEC virulence factors in the temporal and dynamic regulation of host mitochondrial biology.
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Affiliation(s)
- Jennifer Lising Roxas
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Shylaja Ramamurthy
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Katie Cocchi
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Ilga Rutins
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Anusha Harishankar
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Al Agellon
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - John Scott Wilbur
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Gresa Sylejmani
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA
| | - Gayatri Vedantam
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA,Department of Immunobiology, University of Arizona, Tucson, AZ, USA,BIO5 Institute for Collaborative Research, University of Arizona, Tucson, AZ, USA,Research Service, Southern Arizona VA Healthcare System, Tucson, AZ, USA
| | - V.K. Viswanathan
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, USA,Department of Immunobiology, University of Arizona, Tucson, AZ, USA,BIO5 Institute for Collaborative Research, University of Arizona, Tucson, AZ, USA,CONTACT V.K. Viswanathan School of Animal & Comparative Biomedical Sciences, the University of Arizona, Room 227, 1117 E. Lowell Street, Tucson, AZ85721, USA
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