scholarly journals Transcriptional Response of Mycobacterium tuberculosis to Cigarette Smoke Condensate

2021 ◽  
Vol 12 ◽  
Author(s):  
Danicke Willemse ◽  
Chivonne Moodley ◽  
Smriti Mehra ◽  
Deepak Kaushal

Smoking is known to be an added risk factor for tuberculosis (TB), with nearly a quarter of the TB cases attributed to cigarette smokers in the 22 countries with the highest TB burden. Many studies have indicated a link between risk of active TB and cigarette smoke. Smoking is also known to significantly decrease TB cure and treatment completion rate and increase mortality rates. Cigarette smoke contains thousands of volatile compounds including carcinogens, toxins, reactive solids, and oxidants in both particulate and gaseous phase. Yet, to date, limited studies have analyzed the impact of cigarette smoke components on Mycobacterium tuberculosis (Mtb), the causative agent of TB. Here we report the impact of cigarette smoke condensate (CSC) on survival, mutation frequency, and gene expression of Mtb in vitro. We show that exposure of virulent Mtb to cigarette smoke increases the mutation frequency of the pathogen and strongly induces the expression of the regulon controlled by SigH—a global transcriptional regulator of oxidative stress. SigH has previously been shown to be required for Mtb to respond to oxidative stress, survival, and granuloma formation in vivo. A high-SigH expression phenotype is known to be associated with greater virulence of Mtb. In patients with pulmonary TB who smoke, these changes may therefore play an important, yet unexplored, role in the treatment efficacy by potentially enhancing the virulence of tubercle bacilli.

2021 ◽  
Vol 96 ◽  
pp. 107593
Author(s):  
Yiming Ma ◽  
Lijuan Luo ◽  
Xiangming Liu ◽  
Herui Li ◽  
Zihang Zeng ◽  
...  

Nutrients ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 3216
Author(s):  
Maryvonne Ardourel ◽  
Chloé Felgerolle ◽  
Arnaud Pâris ◽  
Niyazi Acar ◽  
Khaoula Ramchani Ben Othman ◽  
...  

To prevent ocular pathologies, new generation of dietary supplements have been commercially available. They consist of nutritional supplement mixing components known to provide antioxidative properties, such as unsaturated fatty acid, resveratrol or flavonoids. However, to date, only one preclinical study has evaluated the impact of a mixture mainly composed of those components (Nutrof Total®) on the retina and demonstrated that in vivo supplementation prevents the retina from structural and functional injuries induced by light. Considering the crucial role played by the glial Müller cells in the retina, particularly to regulate the glutamate cycle to prevent damage in oxidative stress conditions, we questioned the impact of this ocular supplement on the glutamate metabolic cycle. To this end, various molecular aspects associated with the glutamate/glutamine metabolism cycle in Müller cells were investigated on primary Müller cells cultures incubated, or not, with the commercially mix supplement before being subjected, or not, to oxidative conditions. Our results demonstrated that in vitro supplementation provides guidance of the glutamate/glutamine cycle in favor of glutamine synthesis. These results suggest that glutamine synthesis is a crucial cellular process of retinal protection against oxidative damages and could be a key step in the previous in vivo beneficial results provided by the dietary supplementation.


2018 ◽  
Vol 115 (39) ◽  
pp. 9779-9784 ◽  
Author(s):  
Sangeeta Tiwari ◽  
Andries J. van Tonder ◽  
Catherine Vilchèze ◽  
Vitor Mendes ◽  
Sherine E. Thomas ◽  
...  

Reactive oxygen species (ROS)-mediated oxidative stress and DNA damage have recently been recognized as contributing to the efficacy of most bactericidal antibiotics, irrespective of their primary macromolecular targets. Inhibitors of targets involved in both combating oxidative stress as well as being required for in vivo survival may exhibit powerful synergistic action. This study demonstrates that the de novo arginine biosynthetic pathway in Mycobacterium tuberculosis (Mtb) is up-regulated in the early response to the oxidative stress-elevating agent isoniazid or vitamin C. Arginine deprivation rapidly sterilizes the Mtb de novo arginine biosynthesis pathway mutants ΔargB and ΔargF without the emergence of suppressor mutants in vitro as well as in vivo. Transcriptomic and flow cytometry studies of arginine-deprived Mtb have indicated accumulation of ROS and extensive DNA damage. Metabolomics studies following arginine deprivation have revealed that these cells experienced depletion of antioxidant thiols and accumulation of the upstream metabolite substrate of ArgB or ArgF enzymes. ΔargB and ΔargF were unable to scavenge host arginine and were quickly cleared from both immunocompetent and immunocompromised mice. In summary, our investigation revealed in vivo essentiality of the de novo arginine biosynthesis pathway for Mtb and a promising drug target space for combating tuberculosis.


1994 ◽  
Vol 266 (4) ◽  
pp. L382-L388 ◽  
Author(s):  
A. J. Ghio ◽  
J. Stonehuerner ◽  
D. R. Quigley

Deposition of pigmented matter in the lower respiratory tract correlates with the extent of emphysema in smokers as well as with free radical generation and iron accumulation. Pulmonary emphysema is postulated to be mediated by free radical generation which is either directly or indirectly associated with cigarette smoke exposure. The hypothesis was tested that 1) incomplete combustion of tobacco yields humic-like substances (HLS) which 2) deposit in the lung as pigmented particulates, 3) complex iron cations in vitro and in vivo, and 4) have a capacity to catalyze oxidant formation. HLS, isolated by alkali extraction of cigarette smoke condensate (CSC) (Tobacco Health Research Institute, University of Kentucky), demonstrated a high carbon and low carboxylate content on elemental and functional group analyses, respectively, compared with values for HLS sequestered from soils. The HLS isolated from CSC had a capacity to complex iron in vitro and accumulated the metal in vivo after intratracheal instillation in an animal model. Both HLS and its iron complex generated free radicals, and some portion of this oxidant generation was metal dependent. Lung tissue collected at autopsy from smokers contained HLS with an infrared spectrum almost identical to that of the material isolated from CSC. Associations between particulate deposition, metal accumulation, and free radical generation suggest a possible role of HLS in the induction of lung disease following cigarette exposure.


2019 ◽  
Vol 133 (13) ◽  
pp. 1523-1536 ◽  
Author(s):  
Xiao Sun ◽  
Xiuli Feng ◽  
Dandan Zheng ◽  
Ang Li ◽  
Chunyan Li ◽  
...  

Abstract Cigarette smoke (CS) is the major cause of chronic obstructive pulmonary disease (COPD). CS heightens inflammation, oxidative stress and apoptosis. Ergosterol is the main bioactive ingredient in Cordyceps sinensis (C. sinensis), a traditional medicinal herb for various diseases. The objective of this work was to investigate the effects of ergosterol on anti-inflammatory and antioxidative stress as well as anti-apoptosis in a cigarette smoke extract (CSE)-induced COPD model both in vitro and in vivo. Our results demonstrate that CSE induced inflammatory and oxidative stress and apoptosis with the involvement of the Bcl-2 family proteins via the nuclear factor kappa B (NF-κB)/p65 pathway in both 16HBE cells and Balb/c mice. CSE induced epithelial cell death and increased the expression of nitric oxide (NO), interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), malondialdehyde (MAD) and the apoptosis-related proteins cleaved caspase 3/7/9 and cleaved-poly-(ADP)-ribose polymerase (PARP) both in vitro and in vivo, whereas decreased the levels of superoxide dismutase (SOD) and catalase (CAT). Treatment of 16HBE cells and Balb/c mice with ergosterol inhibited CSE-induced inflammatory and oxidative stress and apoptosis by inhibiting the activation of NF-κB/p65. Ergosterol suppressed apoptosis by inhibiting the expression of the apoptosis-related proteins both in vitro and in vivo. Moreover, the usage of QNZ (an inhibitor of NF-κB) also partly demonstrated that NF-κB/p65 pathway was involved in the ergosterol protective progress. These results show that ergosterol suppressed COPD inflammatory and oxidative stress and apoptosis through the NF-κB/p65 pathway, suggesting that ergosterol may be partially responsible for the therapeutic effects of cultured C. sinensis on COPD patients.


2004 ◽  
Vol 58 (2) ◽  
pp. 90-94 ◽  
Author(s):  
Pascale Nguyen Van Binh ◽  
Dong Zhou ◽  
Françoise Baudouin ◽  
Chantal Martin ◽  
Martine Radionoff ◽  
...  

2019 ◽  
Vol 4 (37) ◽  
pp. eaaw6693 ◽  
Author(s):  
Alissa C. Rothchild ◽  
Gregory S. Olson ◽  
Johannes Nemeth ◽  
Lynn M. Amon ◽  
Dat Mai ◽  
...  

Alveolar macrophages (AMs) are the first cells to be infected during Mycobacterium tuberculosis (M.tb.) infection. Thus, the AM response to infection is the first of many steps leading to initiation of the adaptive immune response required for efficient control of infection. A hallmark of M.tb. infection is the slow initiation of the adaptive response, yet the mechanisms responsible for this are largely unknown. To study the initial AM response to infection, we developed a system to identify, sort, and analyze M.tb.-infected AMs from the lung within the first 10 days of infection. In contrast to what has been previously described using in vitro systems, M.tb.-infected AMs up-regulate a cell-protective antioxidant transcriptional signature that is dependent on the lung environment but not bacterial virulence. Computational approaches including pathway analysis and transcription factor motif enrichment analysis identify NRF2 as a master regulator of the response. Using knockout mouse models, we demonstrate that NRF2 drives expression of the cell-protective signature in AMs and impairs the control of early bacterial growth. AMs up-regulate a substantial pro-inflammatory response to M.tb. infection only 10 days after infection, yet comparisons with bystander AMs from the same infected animals demonstrate that M.tb.-infected AMs generate a less robust inflammatory response than the uninfected cells around them. Our findings demonstrate that the initial macrophage response to M.tb. in the lung is far less inflammatory than has previously been described by in vitro systems and may impede the overall host response to infection.


Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2636 ◽  
Author(s):  
Laurine Garros ◽  
Samantha Drouet ◽  
Cyrielle Corbin ◽  
Cédric Decourtil ◽  
Thibaud Fidel ◽  
...  

Flaxseeds are a functional food representing, by far, the richest natural grain source of lignans, and accumulate substantial amounts of other health beneficial phenolic compounds (i.e., flavonols, hydroxycinnamic acids). This specific accumulation pattern is related to their numerous beneficial effects on human health. However, to date, little data is available concerning the relative impact of genetic and geographic parameters on the phytochemical yield and composition. Here, the major influence of the cultivar over geographic parameters on the flaxseed phytochemical accumulation yield and composition is evidenced. The importance of genetic parameters on the lignan accumulation was further confirmed by gene expression analysis monitored by RT-qPCR. The corresponding antioxidant activity of these flaxseed extracts was evaluated, both in vitro, using ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and iron chelating assays, as well as in vivo, by monitoring the impact of UV-induced oxidative stress on the lipid membrane peroxidation of yeast cells. Our results, both the in vitro and in vivo studies, confirm that flaxseed extracts are an effective protector against oxidative stress. The results point out that secoisolariciresinol diglucoside, caffeic acid glucoside, and p-coumaric acid glucoside are the main contributors to the antioxidant capacity. Considering the health benefits of these compounds, the present study demonstrates that the flaxseed cultivar type could greatly influence the phytochemical intakes and, therefore, the associated biological activities. We recommend that this crucial parameter be considered in epidemiological studies dealing with flaxseeds.


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