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Tiwari V, Sharma A, Braga R, Garcia E, Appiah R, Fleeman R, Abuaita BH, Patrauchan M, Doerrler WT. Klebsiella pneumoniae DedA family proteins have redundant roles in divalent cation homeostasis and resistance to phagocytosis. Microbiol Spectr 2024; 12:e0380723. [PMID: 38214522 PMCID: PMC10846249 DOI: 10.1128/spectrum.03807-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 12/04/2023] [Indexed: 01/13/2024] Open
Abstract
The DedA superfamily is a highly conserved family of membrane proteins. Deletion of Escherichia coli yqjA and yghB, encoding related DedA family proteins, results in sensitivity to elevated temperature, antibiotics, and alkaline pH. The human pathogen Klebsiella pneumoniae possesses genes encoding DedA family proteins with >90% amino acid identity to E. coli YqjA and YghB. We hypothesized that the deletion of K. pneumoniae yqjA and yghB will impact its physiology and may reduce its virulence. The K. pneumoniae ΔyqjA ΔyghB mutant (strain VT101) displayed a growth defect at 42°C and alkaline pH sensitivity, not unlike its E. coli counterpart. However, VT101 retained mostly wild-type resistance to antibiotics. We found VT101 was sensitive to the chelating agent EDTA, the anionic detergent SDS, and agents capable of alkalizing the bacterial cytoplasm such as bicarbonate or chloroquine. We could restore growth at alkaline pH and at elevated temperature by addition of 0.5-2 mM Ca2+ or Mg2+ to the culture media. VT101 displayed a slower uptake of calcium, which was dependent upon calcium channel activity. VT201, with similar deletions as VT101 but derived from a virulent K. pneumoniae strain, was highly susceptible to phagocytosis by alveolar macrophages and displayed a defect in the production of capsule. These findings suggest divalent cation homeostasis and virulence are interlinked by common functions of the DedA family.IMPORTANCEKlebsiella pneumoniae is a dangerous human pathogen. The DedA protein family is found in all bacteria and is a membrane transporter often required for virulence and antibiotic resistance. K. pneumoniae possesses homologs of E. coli YqjA and YghB, with 60% amino acid identity and redundant functions, which we have previously shown to be required for tolerance to biocides and alkaline pH. A K. pneumoniae strain lacking yqjA and yghB was found to be sensitive to alkaline pH, elevated temperature, and EDTA/SDS and displayed a defect in calcium uptake. Sensitivity to these conditions was reversed by addition of calcium or magnesium to the growth medium. Introduction of ΔyqjA and ΔyghB mutations into virulent K. pneumoniae resulted in the loss of capsule, increased phagocytosis by macrophages, and a partial loss of virulence. These results show that targeting the Klebsiella DedA family results in impaired divalent cation transport and, in turn, loss of virulence.
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Affiliation(s)
- Vijay Tiwari
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Amit Sharma
- Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Reygan Braga
- Department of Microbiology and Molecular Genetics, College of Arts and Science, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Emily Garcia
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Ridhwana Appiah
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Renee Fleeman
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Basel H. Abuaita
- Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Marianna Patrauchan
- Department of Microbiology and Molecular Genetics, College of Arts and Science, Oklahoma State University, Stillwater, Oklahoma, USA
| | - William T. Doerrler
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
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2
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English BC, Savage HP, Mahan SP, Diaz-Ochoa VE, Young BM, Abuaita BH, Sule G, Knight JS, O’Riordan MX, Bäumler AJ, Tsolis RM. The IRE1α-XBP1 Signaling Axis Promotes Glycolytic Reprogramming in Response to Inflammatory Stimuli. mBio 2023; 14:e0306822. [PMID: 36475773 PMCID: PMC9973330 DOI: 10.1128/mbio.03068-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 11/15/2022] [Indexed: 12/14/2022] Open
Abstract
Immune cells must be able to adjust their metabolic programs to effectively carry out their effector functions. Here, we show that the endoplasmic reticulum (ER) stress sensor Inositol-requiring enzyme 1 alpha (IRE1α) and its downstream transcription factor X box binding protein 1 (XBP1) enhance the upregulation of glycolysis in classically activated macrophages (CAMs). The IRE1α-XBP1 signaling axis supports this glycolytic switch in macrophages when activated by lipopolysaccharide (LPS) stimulation or infection with the intracellular bacterial pathogen Brucella abortus. Importantly, these different inflammatory stimuli have distinct mechanisms of IRE1α activation; while Toll-like receptor 4 (TLR4) supports glycolysis under both conditions, TLR4 is required for activation of IRE1α in response to LPS treatment but not B. abortus infection. Though IRE1α and XBP1 are necessary for maximal induction of glycolysis in CAMs, activation of this pathway is not sufficient to increase the glycolytic rate of macrophages, indicating that the cellular context in which this pathway is activated ultimately dictates the cell's metabolic response and that IRE1α activation may be a way to fine-tune metabolic reprogramming. IMPORTANCE The immune system must be able to tailor its response to different types of pathogens in order to eliminate them and protect the host. When confronted with bacterial pathogens, macrophages, frontline defenders in the immune system, switch to a glycolysis-driven metabolism to carry out their antibacterial functions. Here, we show that IRE1α, a sensor of ER stress, and its downstream transcription factor XBP1 support glycolysis in macrophages during infection with Brucella abortus or challenge with Salmonella LPS. Interestingly, these stimuli activate IRE1α by independent mechanisms. While the IRE1α-XBP1 signaling axis promotes the glycolytic switch, activation of this pathway is not sufficient to increase glycolysis in macrophages. This study furthers our understanding of the pathways that drive macrophage immunometabolism and highlights a new role for IRE1α and XBP1 in innate immunity.
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Affiliation(s)
- Bevin C. English
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
| | - Hannah P. Savage
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
| | - Scott P. Mahan
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
| | - Vladimir E. Diaz-Ochoa
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
| | - Briana M. Young
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
| | - Basel H. Abuaita
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Gautam Sule
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Jason S. Knight
- Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Mary X. O’Riordan
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Andreas J. Bäumler
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
| | - Renée M. Tsolis
- Department of Medical Microbiology and Immunology, University of California—Davis, Davis, California, USA
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3
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Reynolds MB, Hong HS, Michmerhuizen BC, Lawrence ALE, Zhang L, Knight JS, Lyssiotis CA, Abuaita BH, O’Riordan MX. Cardiolipin coordinates inflammatory metabolic reprogramming through regulation of Complex II disassembly and degradation. Sci Adv 2023; 9:eade8701. [PMID: 36735777 PMCID: PMC9897665 DOI: 10.1126/sciadv.ade8701] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 12/30/2022] [Indexed: 05/15/2023]
Abstract
Macrophage metabolic plasticity enables repurposing of electron transport from energy generation to inflammation and host defense. Altered respiratory complex II function has been implicated in cancer, diabetes, and inflammation, but regulatory mechanisms are incompletely understood. Here, we show that macrophage inflammatory activation triggers Complex II disassembly and succinate dehydrogenase subunit B loss through sequestration and selective mitophagy. Mitochondrial fission supported lipopolysaccharide-stimulated succinate dehydrogenase subunit B degradation but not sequestration. We hypothesized that this Complex II regulatory mechanism might be coordinated by the mitochondrial phospholipid cardiolipin. Cardiolipin synthase knockdown prevented lipopolysaccharide-induced metabolic remodeling and Complex II disassembly, sequestration, and degradation. Cardiolipin-depleted macrophages were defective in lipopolysaccharide-induced pro-inflammatory cytokine production, a phenotype partially rescued by Complex II inhibition. Thus, cardiolipin acts as a critical organizer of inflammatory metabolic remodeling.
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Affiliation(s)
- Mack B. Reynolds
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Hanna S. Hong
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Britton C Michmerhuizen
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Anna-Lisa E. Lawrence
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Li Zhang
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Jason S. Knight
- Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Costas A. Lyssiotis
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Basel H. Abuaita
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Mary X. O’Riordan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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4
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Lawrence ALE, Berger RP, Hill DR, Huang S, Yadagiri VK, Bons B, Fields C, Sule GJ, Knight JS, Wobus CE, Spence JR, Young VB, O’Riordan MX, Abuaita BH. Human neutrophil IL1β directs intestinal epithelial cell extrusion during Salmonella infection. PLoS Pathog 2022; 18:e1010855. [PMID: 36191054 PMCID: PMC9578578 DOI: 10.1371/journal.ppat.1010855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 10/18/2022] [Accepted: 09/02/2022] [Indexed: 11/29/2022] Open
Abstract
Infection of the human gut by Salmonella enterica Typhimurium (STM) results in a localized inflammatory disease that is not mimicked in murine infections. To determine mechanisms by which neutrophils, as early responders to bacterial challenge, direct inflammatory programming of human intestinal epithelium, we established a multi-component human intestinal organoid (HIO) model of STM infection. HIOs were micro-injected with STM and seeded with primary human polymorphonuclear leukocytes (PMN-HIOs). PMNs did not significantly alter luminal colonization of Salmonella, but their presence reduced intraepithelial bacterial burden. Adding PMNs to infected HIOs resulted in substantial accumulation of shed TUNEL+ epithelial cells that was driven by PMN Caspase-1 activity. Inhibition of Caspases-1, -3 or -4 abrogated epithelial cell death and extrusion in the infected PMN-HIOs but only Caspase-1 inhibition significantly increased bacterial burden in the PMN-HIO epithelium. Thus, PMNs promote cell death in human intestinal epithelial cells through multiple caspases as a protective response to infection. IL-1β was necessary and sufficient to induce cell shedding in the infected HIOs. These data support a critical innate immune function for human neutrophils in amplifying cell death and extrusion of human epithelial cells from the Salmonella-infected intestinal monolayer. Neutrophils are early responders to Salmonella intestinal infection, but how they influence infection progression and outcome is unknown. Here we use a co-culture model of human intestinal organoids and human primary neutrophils to study the contribution of human neutrophils to Salmonella infection of the intestinal epithelium. We found that neutrophils markedly enhanced epithelial defenses, including enhancing cell extrusion to reduce intraepithelial burden of Salmonella and close association with the epithelium. These findings reveal an early role for neutrophils in the gut in shaping the gut environment to control epithelial infection.
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Affiliation(s)
- Anna-Lisa E. Lawrence
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Ryan P. Berger
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - David R. Hill
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Sha Huang
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Veda K. Yadagiri
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Brooke Bons
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Courtney Fields
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Gautam J. Sule
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Jason S. Knight
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Christiane E. Wobus
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Jason R. Spence
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Vincent B. Young
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Mary X. O’Riordan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail: (MXO); (BHA)
| | - Basel H. Abuaita
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail: (MXO); (BHA)
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5
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Mendel ZI, Reynolds MB, Abuaita BH, O'Riordan MX, Swanson JA. Amino acids suppress macropinocytosis and promote release of CSF1 receptor in macrophages. J Cell Sci 2022; 135:jcs259284. [PMID: 35107133 PMCID: PMC8919328 DOI: 10.1242/jcs.259284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/31/2021] [Indexed: 01/12/2023] Open
Abstract
The internalization of solutes by macropinocytosis provides an essential route for nutrient uptake in many cells. Macrophages increase macropinocytosis in response to growth factors and other stimuli. To test the hypothesis that nutrient environments modulate solute uptake by macropinocytosis, this study analyzed the effects of extracellular amino acids on the accumulation of fluorescent fluid-phase probes in murine macrophages. Nine amino acids, added individually or together, were capable of suppressing macropinocytosis in murine bone marrow-derived macrophages stimulated with the growth factors colony stimulating factor 1 (CSF1) or interleukin 34, both ligands of the CSF1 receptor (CSF1R). The suppressive amino acids did not inhibit macropinocytosis in response to lipopolysaccharide, the chemokine CXCL12, or the tumor promoter phorbol myristate acetate. Suppressive amino acids promoted release of CSF1R from cells and resulted in the formation of smaller macropinosomes in response to CSF1. This suppression of growth factor-stimulated macropinocytosis indicates that different nutrient environments modulate CSF1R levels and bulk ingestion by macropinocytosis, with likely consequences for macrophage growth and function.
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Affiliation(s)
- Zachary I. Mendel
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109,USA
| | - Mack B. Reynolds
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109,USA
- Graduate Program in Immunology, University of Michigan Medical School, Ann Arbor, MI 48109,USA
| | - Basel H. Abuaita
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109,USA
| | - Mary X. O'Riordan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109,USA
| | - Joel A. Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109,USA
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6
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Abuaita BH, Lawrence ALE, Berger RP, Hill DR, Huang S, Yadagiri VK, Bons B, Fields C, Wobus CE, Spence JR, Young VB, O’Riordan MX. Comparative transcriptional profiling of the early host response to infection by typhoidal and non-typhoidal Salmonella serovars in human intestinal organoids. PLoS Pathog 2021; 17:e1009987. [PMID: 34669717 PMCID: PMC8570492 DOI: 10.1371/journal.ppat.1009987] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 11/05/2021] [Accepted: 09/28/2021] [Indexed: 12/18/2022] Open
Abstract
Salmonella enterica represents over 2500 serovars associated with a wide-ranging spectrum of disease; from self-limiting gastroenteritis to invasive infections caused by non-typhoidal serovars (NTS) and typhoidal serovars, respectively. Host factors strongly influence infection outcome as malnourished or immunocompromised individuals can develop invasive infections from NTS, however, comparative analyses of serovar-specific host responses have been constrained by reliance on limited model systems. Here we used human intestinal organoids (HIOs), a three-dimensional “gut-like” in vitro system derived from human embryonic stem cells, to elucidate similarities and differences in host responses to NTS and typhoidal serovars. HIOs discriminated between the two most prevalent NTS, Salmonella enterica serovar Typhimurium (STM) and Salmonella enterica serovar Enteritidis (SE), and typhoidal serovar Salmonella enterica serovar Typhi (ST) in epithelial cell invasion, replication and transcriptional responses. Pro-inflammatory signaling and cytokine output was reduced in ST-infected HIOs compared to NTS infections, consistent with early stages of NTS and typhoidal diseases. While we predicted that ST would induce a distinct transcriptional profile from the NTS strains, more nuanced expression profiles emerged. Notably, pathways involved in cell cycle, metabolism and mitochondrial functions were downregulated in STM-infected HIOs and upregulated in SE-infected HIOs. These results correlated with suppression of cellular proliferation and induction of host cell death in STM-infected HIOs and in contrast, elevated levels of reactive oxygen species production in SE-infected HIOs. Collectively, these results suggest that the HIO model is well suited to reveal host transcriptional programming specific to infection by individual Salmonella serovars, and that individual NTS may provoke unique host epithelial responses during intestinal stages of infection. Salmonella enterica is the major causative agent of bacterial infections associated with contaminated food and water. Salmonella enterica consists of over 2500 serovars of which Typhimurium (STM), Enteritidis (SE) and Typhi (ST) are the three major serovars with medical relevance to humans. These serovars elicit distinctive immune responses and cause different diseases in humans, including self-limiting diarrhea, gastroenteritis and typhoid fever. Differences in the human host response to these serovars are likely to be a major contributing factor to distinct disease outcomes but are not well characterized, possibly due to the limitations of human-derived physiological infection models. Distinct from immortalized epithelial cell culture models, human intestinal organoids (HIOs) are three-dimensional structures derived from embryonic stem cells that differentiate into intestinal mesenchymal and epithelial cells, mirroring key organizational aspects of the intestine. In this study, we used HIOs to monitor transcriptional changes during early stages of STM, SE and ST infection. Our comparative analysis showed that HIO inflammatory responses are the dominant response in all infections, but ST infection induces the weakest upregulation of inflammatory mediators relative to the other serovars. In addition, we identified several cellular processes, including cell cycle and mitochondrial functions, that were inversely regulated between STM and SE infection despite these serovars causing similar localized intestinal infection in humans. Our findings reinforce HIOs as an emerging model system to study Salmonella serovar infection and define global host transcriptional response profiles as a foundation for understanding human infection outcomes.
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Affiliation(s)
- Basel H. Abuaita
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Anna-Lisa E. Lawrence
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Ryan P. Berger
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - David R. Hill
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Sha Huang
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Veda K. Yadagiri
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Brooke Bons
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Courtney Fields
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Christiane E. Wobus
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Jason R. Spence
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Vincent B. Young
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Mary X. O’Riordan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail:
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7
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Abuaita BH, Sule GJ, Schultz TL, Gao F, Knight JS, O'Riordan MX. The IRE1α Stress Signaling Axis Is a Key Regulator of Neutrophil Antimicrobial Effector Function. J Immunol 2021; 207:210-220. [PMID: 34145058 DOI: 10.4049/jimmunol.2001321] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 04/26/2021] [Indexed: 12/12/2022]
Abstract
Activation of the endoplasmic reticulum stress sensor, IRE1α, is required for effective immune responses against bacterial infection and is associated with human inflammatory diseases in which neutrophils are a key immune component. However, the specific role of IRE1α in regulating neutrophil effector function has not been studied. In this study, we show that infection-induced IRE1α activation licenses neutrophil antimicrobial capacity, including IL-1β production, formation of neutrophil extracellular traps (NETs), and methicillin-resistant Staphylococcus aureus (MRSA) killing. Inhibition of IRE1α diminished production of mitochondrial reactive oxygen species and decreased CASPASE-2 activation, which both contributed to neutrophil antimicrobial activity. Mice deficient in CASPASE-2 or neutrophil IRE1α were highly susceptible to MRSA infection and failed to effectively form NETs in the s.c. abscess. IRE1α activation enhanced calcium influx and citrullination of histone H3 independently of mitochondrial reactive oxygen species production, suggesting that IRE1α coordinates multiple pathways required for NET formation. Our data demonstrate that the IRE1α-CASPASE-2 axis is a major driver of neutrophil activity against MRSA infection and highlight the importance of IRE1α in neutrophil antibacterial function.
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Affiliation(s)
- Basel H Abuaita
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI; and
| | - Gautam J Sule
- Division of Rheumatology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Tracey L Schultz
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI; and
| | - Fushan Gao
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI; and
| | - Jason S Knight
- Division of Rheumatology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI
| | - Mary X O'Riordan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI; and
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Sule G, Abuaita BH, Steffes PA, Fernandes AT, Estes SK, Dobry C, Pandian D, Gudjonsson JE, Kahlenberg JM, O'Riordan MX, Knight JS. Endoplasmic reticulum stress sensor IRE1α propels neutrophil hyperactivity in lupus. J Clin Invest 2021; 131:137866. [PMID: 33561013 DOI: 10.1172/jci137866] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 02/05/2021] [Indexed: 12/29/2022] Open
Abstract
Neutrophils amplify inflammation in lupus through the release of neutrophil extracellular traps (NETs). The endoplasmic reticulum stress sensor inositol-requiring enzyme 1 α (IRE1α) has been implicated as a perpetuator of inflammation in various chronic diseases; however, IRE1α has been little studied in relation to neutrophil function or lupus pathogenesis. Here, we found that neutrophils activated by lupus-derived immune complexes demonstrated markedly increased IRE1α ribonuclease activity. Importantly, in neutrophils isolated from patients with lupus, we also detected heightened IRE1α activity that was correlated with global disease activity. Immune complex-stimulated neutrophils produced both mitochondrial ROS (mitoROS) and the activated form of caspase-2 in an IRE1α-dependent fashion, whereas inhibition of IRE1α mitigated immune complex-mediated NETosis (in both human neutrophils and a mouse model of lupus). Administration of an IRE1α inhibitor to lupus-prone MRL/lpr mice over 8 weeks reduced mitoROS levels in peripheral blood neutrophils, while also restraining plasma cell expansion and autoantibody formation. In summary, these data identify a role for IRE1α in the hyperactivity of lupus neutrophils and show that this pathway is upstream of mitochondrial dysfunction, mitoROS formation, and NETosis. We believe that inhibition of the IRE1α pathway is a novel strategy for neutralizing NETosis in lupus, and potentially other inflammatory conditions.
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Affiliation(s)
- Gautam Sule
- Division of Rheumatology, Department of Internal Medicine
| | | | - Paul A Steffes
- Division of Rheumatology, Department of Internal Medicine
| | | | - Shanea K Estes
- Division of Rheumatology, Department of Internal Medicine
| | - Craig Dobry
- Department of Dermatology, University of Michigan, Ann Arbor, Michigan, USA
| | | | | | | | | | - Jason S Knight
- Division of Rheumatology, Department of Internal Medicine
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9
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Gao F, Reynolds MB, Passalacqua KD, Sexton JZ, Abuaita BH, O'Riordan MXD. The Mitochondrial Fission Regulator DRP1 Controls Post-Transcriptional Regulation of TNF-α. Front Cell Infect Microbiol 2021; 10:593805. [PMID: 33520735 PMCID: PMC7840702 DOI: 10.3389/fcimb.2020.593805] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 11/30/2020] [Indexed: 12/12/2022] Open
Abstract
The mitochondrial network plays a critical role in the regulation of innate immune signaling and subsequent production of proinflammatory cytokines such as IFN-β and IL-1β. Dynamin-related protein 1 (DRP1) promotes mitochondrial fission and quality control to maintain cellular homeostasis during infection. However, mechanisms by which DRP1 and mitochondrial dynamics control innate immune signaling and the proinflammatory response are incompletely understood. Here we show that macrophage DRP1 is a positive regulator of TNF-α production during sterile inflammation or bacterial infection. Silencing macrophage DRP1 decreased mitochondrial fragmentation and TNF-α production upon stimulation with lipopolysaccharide (LPS) or methicillin-resistant Staphylococcus aureus (MRSA) infection. The defect in TNF-α induction could not be attributed to changes in gene expression. Instead, DRP1 was required for post-transcriptional control of TNF-α. In contrast, silencing DRP1 enhanced IL-6 and IL-1β production, indicating a distinct mechanism for DRP1-dependent TNF-α regulation. Our results highlight DRP1 as a key player in the macrophage pro-inflammatory response and point to its involvement in post-transcriptional control of TNF-α production.
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Affiliation(s)
- Fushan Gao
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Mack B Reynolds
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Karla D Passalacqua
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Jonathan Z Sexton
- Department of Internal Medicine, Gastroenterology, University of Michigan Medical School, Ann Arbor, MI, United States.,U-M Center for Drug Repurposing, University of Michigan, Ann Arbor, MI, United States.,Michigan Institute for Clinical and Health Research, University of Michigan, Ann Arbor, MI, United States.,Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, United States
| | - Basel H Abuaita
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Mary X D O'Riordan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, United States
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Reynolds MB, Abuaita BH, O’Riordan MX. Cardiolipin dynamics regulate proinflammatory cytokine production in methicillin-resistant Staphylococcus aureus--infected macrophages. The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.152.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
During the immune response, mitochondria serve as a hub for innate immune signaling molecules, such as mitochondrial antiviral signaling protein (MAVS) and Nod Like Receptor Family Pyrin Domain Containing 3 (NLRP3). Cardiolipin, a class of phospholipids found primarily in the inner mitochondrial membrane (IMM), regulates mitochondrial function and cellular stress. In lipopolysaccharide (LPS)-stimulated macrophages, CL translocates from the IMM to the outer mitochondrial membrane (OMM) and recruits NLRP3 to promote inflammasome activation. However, the role of CL in macrophage antibacterial responses remains ill defined. Here, we have made CL-deficient RAW264.7 (RAW) cells by stably knocking down Cardiolipin Synthase (Crls1). Upon infection with methicillin-resistant Staphylococcus aureus (MRSA), Crls1 KD RAW cells showed markedly decreased expression and production of cytokines IL-6, IL-1β, and IFN-β compared to control cells, while TNF-α levels remained similar. For IL-6 and IFN-β, transcript and protein levels in Crls1 KD RAW cells were comparable to unstimulated controls. Surprisingly, these cells showed normal MRSA killing and NF-kB p65 nuclear translocation. These findings suggest a novel role for CL in transcript-level regulation of cytokines during infection. To further investigate CL-dependent innate immune functions, we will use RAW cells expressing a GFP-tagged CL-binding protein, Stomatin-like Protein-2-GFP, to track CL dynamics at membrane-level resolution using 3D structured illumination microscopy. This approach supports earlier studies that describe increased CL OMM localization in response to LPS. Our data suggest an underappreciated role for CL in macrophage responses to MRSA infection.
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Abuaita BH, Schultz TL, O'Riordan MX. Mitochondria-Derived Vesicles Deliver Antimicrobial Reactive Oxygen Species to Control Phagosome-Localized Staphylococcus aureus. Cell Host Microbe 2018; 24:625-636.e5. [PMID: 30449314 DOI: 10.1016/j.chom.2018.10.005] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 08/10/2018] [Accepted: 10/05/2018] [Indexed: 12/20/2022]
Abstract
Pathogenic bacteria taken up into the macrophage phagosome are the target of many anti-microbial mechanisms. Although mitochondria-derived antimicrobial effectors like reactive oxygen species (mROS) aid in bacterial killing, it is unclear how these effectors reach bacteria within the phagosomal lumen. We show here that endoplasmic reticulum stress triggered upon methicillin-resistant Staphylococcus aureus (MRSA) infection induces mROS that are delivered to bacteria-containing phagosomes via mitochondria-derived vesicles (MDVs). The endoplasmic reticulum stress sensor IRE1α induces mROS, specifically hydrogen peroxide (mH2O2), upon MRSA infection. MRSA infection also stimulates the generation of MDVs, which require the mitochondrial stress response factor Parkin, and contributes to mH2O2 accumulation in bacteria-containing phagosomes. Accumulation of phagosomal H2O2 requires Toll-like receptor signaling and the mitochondrial enzyme superoxide dismutase-2 (Sod2), which is delivered to phagosomes by MDVs. Sod2 depletion compromises mH2O2 production and bacterial killing. Thus, mitochondrial redox capacity enhances macrophage antimicrobial function by delivering mitochondria-derived effector molecules into bacteria-containing phagosomes.
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Affiliation(s)
- Basel H Abuaita
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Tracey L Schultz
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Mary X O'Riordan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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12
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Bronner DN, Abuaita BH, Chen X, Fitzgerald KA, Nuñez G, He Y, Yin XM, O'Riordan MXD. Endoplasmic Reticulum Stress Activates the Inflammasome via NLRP3- and Caspase-2-Driven Mitochondrial Damage. Immunity 2015; 43:451-62. [PMID: 26341399 DOI: 10.1016/j.immuni.2015.08.008] [Citation(s) in RCA: 297] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 06/01/2015] [Accepted: 07/28/2015] [Indexed: 01/01/2023]
Abstract
Endoplasmic reticulum (ER) stress is observed in many human diseases, often associated with inflammation. ER stress can trigger inflammation through nucleotide-binding domain and leucine-rich repeat containing (NLRP3) inflammasome, which might stimulate inflammasome formation by association with damaged mitochondria. How ER stress triggers mitochondrial dysfunction and inflammasome activation is ill defined. Here we have used an infection model to show that the IRE1α ER stress sensor regulates regulated mitochondrial dysfunction through an NLRP3-mediated feed-forward loop, independently of ASC. IRE1α activation increased mitochondrial reactive oxygen species, promoting NLRP3 association with mitochondria. NLRP3 was required for ER stress-induced cleavage of caspase-2 and the pro-apoptotic factor, Bid, leading to subsequent release of mitochondrial contents. Caspase-2 and Bid were necessary for activation of the canonical inflammasome by infection-associated or general ER stress. These data identify an NLRP3-caspase-2-dependent mechanism that relays ER stress to the mitochondria to promote inflammation, integrating cellular stress and innate immunity.
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Affiliation(s)
- Denise N Bronner
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Basel H Abuaita
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Xiaoyun Chen
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Katherine A Fitzgerald
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Gabriel Nuñez
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Yongqun He
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109 USA; Unit for Laboratory Animal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109 USA
| | - Xiao-Ming Yin
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Mary X D O'Riordan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109 USA.
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Abuaita BH, Withey JH. Termination of Vibrio cholerae virulence gene expression is mediated by proteolysis of the major virulence activator, ToxT. Mol Microbiol 2011; 81:1640-53. [PMID: 21883522 DOI: 10.1111/j.1365-2958.2011.07798.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Vibrio cholerae is the causative agent of cholera, a severe diarrhoeal illness. V. cholerae produces two major virulence factors: the cholera toxin, which directly causes diarrhoea, and the toxin-coregulated pilus, which is required for intestinal colonization. Production of these virulence factors is dependent on the major virulence regulator, ToxT. Under virulence-inducing growth conditions, transcription factors ToxR and TcpP initially activate transcription of toxT. However, once ToxT has been expressed, it produces more of itself independent of ToxR and TcpP by activating transcription of the long tcpA operon, within which toxT is located. It is known that V. cholerae terminates virulence gene expression prior to escape from the host, but it is unknown how this ToxT-positive feedback loop is broken, an essential step in terminating virulence gene expression. To better understand how ToxT protein activity is regulated, we monitored ToxT accumulation and activity under virulence-inducing and -repressing growth conditions. Our results suggest that ToxT protein undergoes proteolytic degradation to terminate virulence gene expression. This directed degradation of ToxT supports a model for terminating V. cholerae virulence gene expression late in infection, with both ToxT and TcpP undergoing proteolysis prior to escape from the host.
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Affiliation(s)
- Basel H Abuaita
- Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI, USA
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Abuaita BH, Withey JH. Genetic screening for bacterial mutants in liquid growth media by fluorescence-activated cell sorting. J Microbiol Methods 2010; 84:109-13. [PMID: 21094189 DOI: 10.1016/j.mimet.2010.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 10/28/2010] [Accepted: 11/07/2010] [Indexed: 11/25/2022]
Abstract
Many bacterial pathogens have defined in vitro virulence inducing conditions in liquid media which lead to production of virulence factors important during an infection. Identifying mutants that no longer respond to virulence inducing conditions will increase our understanding of bacterial pathogenesis. However, traditional genetic screens require growth on solid media. Bacteria in a single colony are in every phase of the growth curve, which complicates the analysis and makes screens for growth phase-specific mutants problematic. Here, we utilize fluorescence-activated cell sorting in conjunction with random transposon mutagenesis to isolate bacteria grown in liquid media that are defective in virulence activation. This method permits analysis of an entire bacterial population in real time and selection of individual bacterial mutants with the desired gene expression profile at any time point after induction. We have used this method to identify Vibrio cholerae mutants defective in virulence induction.
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Affiliation(s)
- Basel H Abuaita
- Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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