scholarly journals The Dynll1-Cox4i1 Complex Regulates Intracellular Pathogen Clearance via Release of Mitochondrial Reactive Oxygen Species

2020 ◽  
Vol 88 (4) ◽  
Author(s):  
Jiangbei Yuan ◽  
Zihan Zheng ◽  
Liting Wang ◽  
Haiying Ran ◽  
Xiangyu Tang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Listeria Monocytogenes ◽  
Membrane Proteins ◽  
Defense Mechanisms ◽  
Reactive Oxygen ◽  
Cellular Membrane ◽  
Oxygen Species ◽  
Dynein Light Chain ◽  
Mitochondrial Reactive Oxygen Species ◽  
Content Type

ABSTRACT Cellular membrane proteins are a critical part of the host defense mechanisms against infection and intracellular survival of Listeria monocytogenes. The complex spatiotemporal regulation of bacterial infection by various membrane proteins has been challenging to study. Here, using mass spectrometry analyses, we depicted the dynamic expression landscape of membrane proteins upon L. monocytogenes infection in dendritic cells. We showed that Dynein light chain 1 (Dynll1) formed a persistent complex with the mitochondrial cytochrome oxidase Cox4i1, which is disturbed by pathogen insult. We discovered that the dissociation of the Dynll1-Cox4i1 complex is required for the release of mitochondrial reactive oxygen species and serves as a regulator of intracellular proliferation of Listeria monocytogenes. Our study shows that Dynll1 is an inhibitor of mitochondrial reactive oxygen species and can serve as a potential molecular drug target for antibacterial treatment.

scholarly journals Blue-Light Inhibition of Listeria monocytogenes Growth Is Mediated by Reactive Oxygen Species and Is Influenced by σBand the Blue-Light Sensor Lmo0799

2016 ◽  
Vol 82 (13) ◽  
pp. 4017-4027 ◽  
Author(s):  
Beth O'Donoghue ◽  
Kerrie NicAogáin ◽  
Claire Bennett ◽  
Alan Conneely ◽  
Teresa Tiensuu ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Listeria Monocytogenes ◽  
Stress Response ◽  
Blue Light ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Content Type ◽  
General Stress Response ◽  
General Stress ◽  
Light Sensor

ABSTRACTListeria monocytogenessenses blue light via the flavin mononucleotide-containing sensory protein Lmo0799, leading to activation of the general stress response sigma factor SigB (σB). In this study, we investigated the physiological response of this foodborne pathogen to blue light. We show that blue light (460 to 470 nm) doses of 1.5 to 2 mW cm−2cause inhibition of growth on agar-based and liquid culture media. The inhibitory effects are dependent on cell density, with reduced effects evident when high cell numbers are present. The addition of 20 mM dimethylthiourea, a scavenger of reactive oxygen species, or catalase to the medium reverses the inhibitory effects of blue light, suggesting that growth inhibition is mediated by the formation of reactive oxygen species. A mutant strain lacking σB(ΔsigB) was found to be less inhibited by blue light than the wild type, likely indicating the energetic cost of deploying the general stress response. When a lethal dose of light (8 mW cm−2) was applied to cells, the ΔsigBmutant displayed a marked increase in sensitivity to light compared to the wild type. To investigate the role of the blue-light sensor Lmo0799, mutants were constructed that either had a deletion of the gene (Δlmo0799) or alteration in a conserved cysteine residue at position 56, which is predicted to play a pivotal role in the photocycle of the protein (lmo0799C56A). Both mutants displayed phenotypes similar to the ΔsigBmutant in the presence of blue light, providing genetic evidence that residue 56 is critical for light sensing inL. monocytogenes. Taken together, these results demonstrate thatL. monocytogenesis inhibited by blue light in a manner that depends on reactive oxygen species, and they demonstrate clear light-dependent phenotypes associated with σBand the blue-light sensor Lmo0799.IMPORTANCEListeria monocytogenesis a bacterial foodborne pathogen that can cause life-threatening infections in humans. It is known to be able to sense and respond to visible light. In this study, we examine the effects of blue light on the growth and survival of this pathogen. We show that growth can be inhibited at comparatively low doses of blue light, and that at higher doses,L. monocytogenescells are killed. We present evidence suggesting that blue light inhibits this organism by causing the production of reactive oxygen species, such as hydrogen peroxide. We help clarify the mechanism of light sensing by constructing a “blind” version of the blue-light sensor protein. Finally, we show that activation of the general stress response by light has a negative effect on growth, probably because cellular resources are diverted into protective mechanisms rather than growth.

scholarly journals Histone Deacetylase Inhibitors Promote Mitochondrial Reactive Oxygen Species Production and Bacterial Clearance by Human Macrophages

2015 ◽  
Vol 60 (3) ◽  
pp. 1521-1529 ◽  
Author(s):  
Juliana K. Ariffin ◽  
Kaustav das Gupta ◽  
Ronan Kapetanovic ◽  
Abishek Iyer ◽  
Robert C. Reid ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Histone Deacetylase Inhibitors ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Bacterial Clearance ◽  
Mitochondrial Reactive Oxygen Species ◽  
Bacterial Challenge ◽  
Content Type ◽  
Human Macrophages ◽  
Species Production

Broad-spectrum histone deacetylase inhibitors (HDACi) are used clinically as anticancer agents, and more isoform-selective HDACi have been sought to modulate other conditions, including chronic inflammatory diseases. Mouse studies suggest that HDACi downregulate immune responses and may compromise host defense. However, their effects on human macrophage antimicrobial responses are largely unknown. Here, we show that overnight pretreatment of human macrophages with HDACi prior to challenge withSalmonella entericaserovar Typhimurium orEscherichia coliresults in significantly reduced intramacrophage bacterial loads, which likely reflect the fact that this treatment regime impairs phagocytosis. In contrast, cotreatment of human macrophages with HDACi at the time of bacterial challenge did not impair phagocytosis; instead, HDACi cotreatment actually promoted clearance of intracellularS. Typhimurium andE. coli. Mechanistically, treatment of human macrophages with HDACi at the time of bacterial infection enhanced mitochondrial reactive oxygen species generation by these cells. The capacity of HDACi to promote the clearance of intracellular bacteria from human macrophages was abrogated when cells were pretreated with MitoTracker Red CMXRos, which perturbs mitochondrial function. The HDAC6-selective inhibitor tubastatin A promoted bacterial clearance from human macrophages, whereas the class I HDAC inhibitor MS-275, which inhibits HDAC1 to -3, had no effect on intracellular bacterial loads. These data are consistent with HDAC6 and/or related HDACs constraining mitochondrial reactive oxygen species production from human macrophages during bacterial challenge. Our findings suggest that, whereas long-term HDACi treatment regimes may potentially compromise host defense, selective HDAC inhibitors may have applications in treating acute bacterial infections.

scholarly journals Chlamydia muridarum Infection of Macrophages Elicits Bactericidal Nitric Oxide Production via Reactive Oxygen Species and Cathepsin B

2015 ◽  
Vol 83 (8) ◽  
pp. 3164-3175 ◽  
Author(s):  
Krithika Rajaram ◽  
David E. Nelson
Keyword(s):  
Nitric Oxide ◽  
Reactive Oxygen Species ◽  
Cathepsin B ◽  
Defense Mechanisms ◽  
Reactive Oxygen ◽  
Host Protein ◽  
Radical Scavenger ◽  
Oxygen Species ◽  
Content Type ◽  
Chlamydia Muridarum

The ability of certain species ofChlamydiato inhibit the biogenesis of phagolysosomes permits their survival and replication within macrophages. The survival of macrophage-adapted chlamydiae correlates with the multiplicity of infection (MOI), and optimal chlamydial growth occurs in macrophages infected at an MOI of ≤1. In this study, we examined the replicative capacity ofChlamydia muridarumin the RAW 264.7 murine macrophage cell line at different MOIs.C. muridarumproductively infected these macrophages at low MOIs but yielded few viable elementary bodies (EBs) when macrophages were infected at a moderate (10) or high (100) MOI. While high MOIs caused cytotoxicity and irreversible host cell death, macrophages infected at a moderate MOI did not show signs of cytotoxicity until late in the infectious cycle. Inhibition of host protein synthesis rescuedC. muridarumin macrophages infected at a moderate MOI, implying that chlamydial growth was blocked by activated defense mechanisms. Conditioned medium from these macrophages was antichlamydial and contained elevated levels of interleukin 1β (IL-1β), IL-6, IL-10, and beta interferon (IFN-β). Macrophage activation depended on Toll-like receptor 2 (TLR2) signaling, and cytokine production required live, transcriptionally active chlamydiae. A hydroxyl radical scavenger and inhibitors of inducible nitric oxide synthase (iNOS) and cathepsin B also reversed chlamydial killing. High levels of reactive oxygen species (ROS) led to an increase in cathepsin B activity, and pharmacological inhibition of ROS and cathepsin B reduced iNOS expression. Our data demonstrate that MOI-dependent TLR2 activation of macrophages results in iNOS induction via a novel ROS- and cathepsin-dependent mechanism to facilitateC. muridarumclearance.

scholarly journals Ubiquitination of Listeria Virulence Factor InlC Contributes to the Host Response to Infection

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Edith Gouin ◽  
Damien Balestrino ◽  
Orhan Rasid ◽  
Marie-Anne Nahori ◽  
Véronique Villiers ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Immune Response ◽  
Listeria Monocytogenes ◽  
Host Response ◽  
Reactive Oxygen Species Production ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Pathogenic Potential ◽  
Content Type ◽  
Species Production

ABSTRACT Listeria monocytogenes is a pathogenic bacterium causing potentially fatal foodborne infections in humans and animals. While the mechanisms used by Listeria to manipulate its host have been thoroughly characterized, how the host controls bacterial virulence factors remains to be extensively deciphered. Here, we found that the secreted Listeria virulence protein InlC is monoubiquitinated by the host cell machinery on K224, restricting infection. We show that the ubiquitinated form of InlC interacts with the intracellular alarmin S100A9, resulting in its stabilization and in increased reactive oxygen species production by neutrophils in infected mice. Collectively, our results suggest that posttranslational modification of InlC exacerbates the host response upon Listeria infection. IMPORTANCE The pathogenic potential of Listeria monocytogenes relies on the production of an arsenal of virulence determinants that have been extensively characterized, including surface and secreted proteins of the internalin family. We have previously shown that the Listeria secreted internalin InlC interacts with IκB kinase α to interfere with the host immune response (E. Gouin, M. Adib-Conquy, D. Balestrino, M.-A. Nahori, et al., Proc Natl Acad Sci USA, 107:17333–17338, 2010, https://doi.org/10.1073/pnas.1007765107). In the present work, we report that InlC is monoubiquitinated on K224 upon infection of cells and provide evidence that ubiquitinated InlC interacts with and stabilizes the alarmin S100A9, which is a critical regulator of the immune response and inflammatory processes. Additionally, we show that ubiquitination of InlC causes an increase in reactive oxygen species production by neutrophils in mice and restricts Listeria infection. These findings are the first to identify a posttranscriptional modification of an internalin contributing to host defense.

scholarly journals Overlapping and Complementary Oxidative Stress Defense Mechanisms in Nontypeable Haemophilus influenzae

2014 ◽  
Vol 197 (2) ◽  
pp. 277-285 ◽  
Author(s):  
Alistair Harrison ◽  
Beth D. Baker ◽  
Robert S. Munson
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Haemophilus Influenzae ◽  
Fenton Reaction ◽  
Defense Mechanisms ◽  
Reactive Oxygen ◽  
Chronic Obstructive ◽  
Oxygen Species ◽  
Nontypeable Haemophilus Influenzae ◽  
Content Type

The Gram-negative commensal bacterium nontypeableHaemophilus influenzae(NTHI) can cause respiratory tract diseases that include otitis media, sinusitis, exacerbations of chronic obstructive pulmonary disease, and bronchitis. During colonization and infection, NTHI withstands oxidative stress generated by reactive oxygen species produced endogenously, by the host, and by other copathogens and flora. These reactive oxygen species include superoxide, hydrogen peroxide (H2O2), and hydroxyl radicals, whose killing is amplified by iron via the Fenton reaction. We previously identified genes that encode proteins with putative roles in protection of the NTHI isolate strain 86-028NP against oxidative stress. These include catalase (HktE), peroxiredoxin/glutaredoxin (PgdX), and a ferritin-like protein (Dps). Strains were generated with mutations inhktE,pgdX, anddps. ThehktEmutant and apgdX hktEdouble mutant were more sensitive than the parent to killing by H2O2. Conversely, thepgdXmutant was more resistant to H2O2due to increased catalase activity. Supporting the role of killing via the Fenton reaction, binding of iron by Dps significantly mitigated the effect of H2O2-mediated killing. NTHI thus utilizes several effectors to resist oxidative stress, and regulation of free iron is critical to this protection. These mechanisms will be important for successful colonization and infection by this opportunistic human pathogen.

scholarly journals Astaxanthin Prevents Atrophy in Slow Muscle Fibers by Inhibiting Mitochondrial Reactive Oxygen Species via a Mitochondria-Mediated Apoptosis Pathway

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 379
Author(s):  
Luchuanyang Sun ◽  
Nobuyuki Miyaji ◽  
Min Yang ◽  
Edward M. Mills ◽  
Shigeto Taniyama ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Lipid Bilayer ◽  
Muscle Atrophy ◽  
Soleus Muscle ◽  
Reactive Oxygen ◽  
H2o2 Production ◽  
Oxygen Species ◽  
Mitochondrial Reactive Oxygen Species ◽  
Tail Suspension ◽  
Apoptosis Pathway

Astaxanthin (AX) is a carotenoid that exerts potent antioxidant activity and acts in the lipid bilayer. This study aimed to investigate the effects of AX on muscle-atrophy-mediated disturbance of mitochondria, which have a lipid bilayer. Tail suspension was used to establish a muscle-atrophied mouse model. AX diet fed to tail-suspension mice prevented loss of muscle weight, inhibited the decrease of myofiber size, and restrained the increase of hydrogen peroxide (H2O2) production in the soleus muscle. Additionally, AX improved downregulation of mitochondrial respiratory chain complexes I and III in the soleus muscle after tail suspension. Meanwhile, AX promoted mitochondrial biogenesis by upregulating the expressions of adenosine 5′-monophosphate–activated protein kinase (AMPK) α-1, peroxisome proliferator–activated receptor (PPAR)-γ, and creatine kinase in mitochondrial (Ckmt) 2 in the soleus muscle of tail-suspension mice. To confirm the AX phenotype in the soleus muscle, we examined its effects on mitochondria using Sol8 myotubes derived from the soleus muscle. We found that AX was preferentially detected in the mitochondrial fraction; it significantly suppressed mitochondrial reactive oxygen species (ROS) production in Sol8 myotubes. Moreover, AX inhibited the activation of caspase 3 via inhibiting the release of cytochrome c into the cytosol in antimycin A–treated Sol8 myotubes. These results suggested that AX protected the functional stability of mitochondria, alleviated mitochondrial oxidative stress and mitochondria-mediated apoptosis, and thus, prevented muscle atrophy.

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