scholarly journals Piperacillin triggers virulence factor biosynthesis via the oxidative stress response in Burkholderia thailandensis

2021 ◽  
Vol 118 (26) ◽  
pp. e2021483118
Author(s):  
Anran Li ◽  
Bethany K. Okada ◽  
Paul C. Rosen ◽  
Mohammad R. Seyedsayamdost
Keyword(s):  
Oxidative Stress ◽  
Virulence Factor ◽  
Low Dose ◽  
Biosynthetic Genes ◽  
Burkholderia Thailandensis ◽  
Chemical Genetic ◽  
Regulatory Circuits ◽  
Regulatory Input ◽  
Redox Sensing ◽  
Approved Drugs

Natural products have been an important source of therapeutic agents and chemical tools. The recent realization that many natural product biosynthetic genes are silent or sparingly expressed during standard laboratory growth has prompted efforts to investigate their regulation and develop methods to induce their expression. Because it is difficult to intuit signals that induce a given biosynthetic locus, we recently implemented a forward chemical-genetic approach to identify such inducers. In the current work, we applied this approach to nine silent biosynthetic loci in the model bacterium Burkholderia thailandensis to systematically screen for elicitors from a library of Food and Drug Administration–approved drugs. We find that β-lactams, fluoroquinolones, antifungals, and, surprisingly, calcimimetics, phenothiazine antipsychotics, and polyaromatic antidepressants are the most effective global inducers of biosynthetic genes. Investigations into the mechanism of stimulation of the silent virulence factor malleicyprol by the β-lactam piperacillin allowed us to elucidate the underlying regulatory circuits. Low-dose piperacillin causes oxidative stress, thereby inducing redox-sensing transcriptional regulators, which activate malR, a pathway-specific positive regulator of the malleicyprol gene cluster. Malleicyprol is thus part of the OxyR and SoxR regulons in B. thailandensis, allowing the bacterium to initiate virulence in response to oxidative stress. Our work catalogs a diverse array of elicitors and a previously unknown regulatory input for secondary metabolism in B. thailandensis.

scholarly journals Multi-Omic Analyses Provide Links between Low-Dose Antibiotic Treatment and Induction of Secondary Metabolism in Burkholderia thailandensis

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Anran Li ◽  
Dainan Mao ◽  
Aya Yoshimura ◽  
Paul C. Rosen ◽  
W. Lance Martin ◽  
...  
Keyword(s):  
Secondary Metabolism ◽  
Low Dose ◽  
Transcriptional Regulator ◽  
Low Doses ◽  
Burkholderia Thailandensis ◽  
Content Type ◽  
Bacterial Physiology ◽  
Regulatory Circuits ◽  
Starting Point ◽  
Underlying Mechanisms

ABSTRACT Low doses of antibiotics can trigger secondary metabolite biosynthesis in bacteria, but the underlying mechanisms are generally unknown. We sought to better understand this phenomenon by studying how the antibiotic trimethoprim activates the synthesis of the virulence factor malleilactone in Burkholderia thailandensis. Using transcriptomics, quantitative multiplexed proteomics, and primary metabolomics, we systematically mapped the changes induced by trimethoprim. Surprisingly, even subinhibitory doses of the antibiotic resulted in broad transcriptional and translational alterations, with ∼8.5% of the transcriptome and ∼5% of the proteome up- or downregulated >4-fold. Follow-up studies with genetic-biochemical experiments showed that the induction of malleilactone synthesis can be sufficiently explained by the accumulation of methionine biosynthetic precursors, notably homoserine, as a result of inhibition of the folate pathway. Homoserine activated the malleilactone gene cluster via the transcriptional regulator MalR and gave rise to a secondary metabolome which was very similar to that generated by trimethoprim. Our work highlights the expansive changes that low-dose trimethoprim induces on bacterial physiology and provides insights into its stimulatory effect on secondary metabolism. IMPORTANCE The discovery of antibiotics ranks among the most significant accomplishments of the last century. Although the targets of nearly all clinical antibiotics are known, our understanding regarding their natural functions and the effects of subinhibitory concentrations is in its infancy. Stimulatory rather than inhibitory functions have been attributed to low-dose antibiotics. Among these, we previously found that antibiotics activate silent biosynthetic genes and thereby enhance the metabolic output of bacteria. The regulatory circuits underlying this phenomenon are unknown. We take a first step toward elucidating these circuits and show that low doses of trimethoprim (Tmp) have cell-wide effects on the saprophyte Burkholderia thailandensis. Most importantly, inhibition of one-carbon metabolic processes by Tmp leads to an accumulation of homoserine, which induces the production of an otherwise silent cytotoxin via a LuxR-type transcriptional regulator. These results provide a starting point for uncovering the molecular basis of the hormetic effects of antibiotics.

scholarly journals Low-dose irradiation reduces forced swim test-induced immobility and oxidative stress in mice

2021 ◽  
Vol 165 ◽  
pp. 56-57
Author(s):  
Shota Naoe ◽  
Takahiro Kataoka ◽  
Hina Shuto ◽  
Junki Yano ◽  
Tetsuya Nakada ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Low Dose ◽  
Forced Swim Test ◽  
Swim Test ◽  
Dose Irradiation ◽  
Forced Swim ◽  
And Oxidative Stress

Low-dose aspirin prevents age-related endothelial dysfunction in a mouse model of physiological aging

2008 ◽  
Vol 294 (4) ◽  
pp. H1562-H1570 ◽  
Author(s):  
Hélène Bulckaen ◽  
Gaétan Prévost ◽  
Eric Boulanger ◽  
Géraldine Robitaille ◽  
Valérie Roquet ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endothelial Dysfunction ◽  
Protective Effect ◽  
Structural Changes ◽  
Low Dose ◽  
Age Groups ◽  
Dose Aspirin ◽  
Age Related ◽  
Low Dose Aspirin ◽  
Old Mice

The age-related impairment of endothelium-dependent vasodilatation contributes to increased cardiovascular risk in the elderly. For primary and secondary prevention, aspirin can reduce the incidence of cardiovascular events in this patient population. The present work evaluated the effect of low-dose aspirin on age-related endothelial dysfunction in C57B/J6 aging mice and investigated its protective antioxidative effect. Age-related endothelial dysfunction was assessed by the response to acetylcholine of phenylephrine-induced precontracted aortic segments isolated from 12-, 36-, 60-, and 84-wk-old mice. The effect of low-dose aspirin was examined in mice presenting a decrease in endothelial-dependent relaxation (EDR). The effects of age and aspirin treatment on structural changes were determined in mouse aortic sections. The effect of aspirin on the oxidative stress markers malondialdehyde and 8-hydroxy-2′-deoxyguanosine (8-OhdG) was also quantified. Compared with that of 12-wk-old mice, the EDR was significantly reduced in 60- and 84-wk-old mice ( P < 0.05); 68-wk-old mice treated with aspirin displayed a higher EDR compared with control mice of the same age (83.9 ± 4 vs. 66.3 ± 5%; P < 0.05). Aspirin treatment decreased 8-OHdG levels ( P < 0.05), but no significant effect on intima/media thickness ratio was observed. The protective effect of aspirin was not observed when treatment was initiated in older mice (96 wk of age). It was found that low-dose aspirin is able to prevent age-related endothelial dysfunction in aging mice. However, the absence of this effect in the older age groups demonstrates that treatment should be initiated early on. The underlying mechanism may involve the protective effect of aspirin against oxidative stress.

scholarly journals Lipotropes promote immunobiochemical plasticity and protect fish against low-dose pesticide-induced oxidative stress

2013 ◽  
Vol 19 (1) ◽  
pp. 61-81 ◽  
Author(s):  
N. A. Muthappa ◽  
Subodh Gupta ◽  
Sona Yengkokpam ◽  
Dipesh Debnath ◽  
Neeraj Kumar ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Low Dose

scholarly journals Comparative study of hydrochlorothiazide and indapamide on the anti-atherogenic potential of losartan in cholesterol fed rat

1970 ◽  
Vol 36 (1) ◽  
pp. 14-19
Author(s):  
Md. Zakirul Islam ◽  
Md. Sayedur Rahman
Keyword(s):  
Oxidative Stress ◽  
Body Weight ◽  
Low Dose ◽  
Rat Aorta ◽  
Antioxidant Effect ◽  
Hypolipidemic Effect ◽  
Cholesterol Diet ◽  
Cholesterol Feeding ◽  
Atherosclerotic Change ◽  
And Oxidative Stress

The study was conducted to evaluate the anti-atherogenic potential of losartan and to assess the effects of hydrochlorothiazide and indapamide on losartan activity in rat. Cholesterol diet (0.5%) for 12 weeks led to significant hyperlipidemia, increased body weight and oxidative stress in erythrocyte. While, losartan, hydrochlorothiazide and indapamide treatment continued for next 12 weeks, losartan showed anti-atherogenic activity reflected by hypolipidemic effect and antioxidant effect in erythrocyte. This activity was abolished by addition of hydrochlorothiazide with losartan but remained unaltered by addition of indapamide with losartan. Atherosclerotic change and oxidative stress were not found in rat aorta, which may be due to short duration and low dose of cholesterol feeding. Hydrochlorothiazide treatment was associated with hypokalemia, which was not present in losartan or indapamide treatment. This study suggests that indapamide might be co-administered with losartan conserving the essential anti-atherogenic potential of losartan.Online: 13 July 2010DOI: http://dx.doi.org/10.3329/bmrcb.v36i1.5447Bangladesh Med Res Counc Bull 2010; 36: 14-19   

Dyslipdemia induced by chronic low dose co-exposure to lead, cadmium and manganese in rats: the role of oxidative stress

2017 ◽  
Vol 53 ◽  
pp. 199-205 ◽  
Author(s):  
Olusola Olalekan Oladipo ◽  
Joseph Olusegun Ayo ◽  
Suleiman Folorunsho Ambali ◽  
Bisalla Mohammed ◽  
Tanang Aluwong
Keyword(s):  
Oxidative Stress ◽  
Low Dose

scholarly journals Low-Dose Ionizing Radiation Therapy: A Novel Treatment for Post-Concussion Syndrome?

Dose-Response ◽  
2021 ◽  
Vol 19 (4) ◽  
pp. 155932582110443
Author(s):  
Paul A. Oakley
Keyword(s):  
Oxidative Stress ◽  
Radiation Therapy ◽  
Ionizing Radiation ◽  
Neurodegenerative Disease ◽  
Low Dose ◽  
Post Injury ◽  
Post Concussion Syndrome ◽  
Persistent Symptoms ◽  
Age Related ◽  
Alzhiemer's Disease

A subset of victims who experience concussion suffer from persistent symptoms spanning months to years post-injury, termed post-concussion syndrome (PCS). Problematically, there is lack of consensus for the treatment of PCS. Concussion injury involves a neurometabolic cascade leading to oxidative stress and neuroinflammation which parallels the oxidative stress loading occuring from age-related neurodegenerative conditions. Historical and recent evidence has emerged showing the efficacy of low-dose radiation therapy for many human diseases including neurodegenerative diseases such as Alzhiemer’s disease (AD). Due to the pathognomonic similarities of oxidative stress and neuroinflammation involved in PCS and neurodegenerative disease, treatments that prove successful for neurodegenerative disease may prove successful for PCS. Recently, low-dose ionizing radiation therapy (LDIR) has been documented to show a reversal of many symptoms in AD, including improved cognition. LDIR is thought to induce a switching from proinflammatory M1 phenotype to an anti-inflammatory M2 phenotype. In other words, a continual upregulation of the adaptive protection systems via LDIR induces health enhancement. It is hypothesized LDIR treatment for PCS would mimic that seen from early evidence of LDIR treatment of AD patients who suffer from similar oxidative stress loading. We propose the application of LDIR is a promising, untapped treatment for PCS.

scholarly journals Metformin Corrects Glucose Metabolism Reprogramming and NLRP3 Inflammasome-Induced Pyroptosis via Inhibiting the TLR4/NF-κB/PFKFB3 Signaling in Trophoblasts: Implication for a Potential Therapy of Preeclampsia

2021 ◽  
Vol 2021 ◽  
pp. 1-22
Author(s):  
Yang Zhang ◽  
Weifang Liu ◽  
Yanqi Zhong ◽  
Qi Li ◽  
Mengying Wu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nlrp3 Inflammasome ◽  
Low Dose ◽  
Therapeutic Potential ◽  
Metabolic Phenotypes ◽  
Pyrin Domain ◽  
Underlying Mechanisms ◽  
And Oxidative Stress ◽  
Receptor Family

NOD-like receptor family, pyrin domain-containing protein 3 (NLRP3) inflammasome-mediated pyroptosis is a crucial event in the preeclamptic pathogenesis, tightly linked with the uteroplacental TLR4/NF-κB signaling. Trophoblastic glycometabolism reprogramming has now been noticed in the preeclampsia pathogenesis, plausibly modulated by the TLR4/NF-κB signaling as well. Intriguingly, cellular pyroptosis and metabolic phenotypes may be inextricably linked and interacted. Metformin (MET), a widely accepted NF-κB signaling inhibitor, may have therapeutic potential in preeclampsia while the underlying mechanisms remain unclear. Herein, we investigated the role of MET on trophoblastic pyroptosis and its relevant metabolism reprogramming. The safety of pharmacologic MET concentration to trophoblasts was verified at first, which had no adverse effects on trophoblastic viability. Pharmacological MET concentration suppressed NLRP3 inflammasome-induced pyroptosis partly through inhibiting the TLR4/NF-κB signaling in preeclamptic trophoblast models induced via low-dose lipopolysaccharide. Besides, MET corrected the glycometabolic reprogramming and oxidative stress partly via suppressing the TLR4/NF-κB signaling and blocking transcription factor NF-κB1 binding on the promoter PFKFB3, a potent glycolytic accelerator. Furthermore, PFKFB3 can also enhance the NF-κB signaling, reduce NLRP3 ubiquitination, and aggravate pyroptosis. However, MET suppressed pyroptosis partly via inhibiting PFKFB3 as well. These results provided that the TLR4/NF-κB/PFKFB3 pathway may be a novel link between metabolism reprogramming and NLRP3 inflammasome-induced pyroptosis in trophoblasts. Further, MET alleviates the NLRP3 inflammasome-induced pyroptosis, which partly relies on the regulation of TLR4/NF-κB/PFKFB3-dependent glycometabolism reprogramming and redox disorders. Hence, our results provide novel insights into the pathogenesis of preeclampsia and propose MET as a potential therapy.

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