scholarly journals Whole-Cell Screen of Fragment Library Identifies Gut Microbiota Metabolite Indole Propionic Acid as Antitubercular

2017 ◽  
Vol 62 (3) ◽  
Author(s):  
Dereje A. Negatu ◽  
Joe J. J. Liu ◽  
Matthew Zimmerman ◽  
Firat Kaya ◽  
Véronique Dartois ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Molecular Mass ◽  
Propionic Acid ◽  
Bacterial Load ◽  
Cell Activity ◽  
Antitubercular Activity ◽  
Whole Cell ◽  
Content Type ◽  
Dependent Growth

ABSTRACT Several key antituberculosis drugs, including pyrazinamide, with a molecular mass of 123.1 g/mol, are smaller than the usual drug-like molecules. Current drug discovery efforts focus on the screening of larger compounds with molecular masses centered around 400 to 500 g/mol. Fragment (molecular mass < 300 g/mol) libraries have not been systematically explored for antitubercular activity. Here we screened a collection of 1,000 fragments, present in the Maybridge Ro3 library, for whole-cell activity against Mycobacterium tuberculosis . Twenty-nine primary hits showed dose-dependent growth inhibition equal to or better than that of pyrazinamide. The most potent hit, indole propionic acid [IPA; 3-(1 H -indol-3-yl)propanoic acid], a metabolite produced by the gut microbiota, was profiled in vivo . The molecule was well tolerated in mice and showed adequate pharmacokinetic properties. In a mouse model of acute M. tuberculosis infection, IPA reduced the bacterial load in the spleen 7-fold. Our results suggest that IPA should be evaluated as an add-on to current regimens and that fragment libraries should be further explored to identify antimycobacterial lead candidates.

scholarly journals In VitroandIn VivoCharacterization of the Novel Oxabicyclooctane-Linked Bacterial Topoisomerase Inhibitor AM-8722, a Selective, Potent Inhibitor of Bacterial DNA Gyrase

2016 ◽  
Vol 60 (8) ◽  
pp. 4830-4839 ◽  
Author(s):  
Christopher M. Tan ◽  
Charles J. Gill ◽  
Jin Wu ◽  
Nathalie Toussaint ◽  
Jingjun Yin ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Antibacterial Agents ◽  
Cell Activity ◽  
Dna Gyrase ◽  
Topoisomerase Iv ◽  
Bacterial Dna ◽  
Whole Cell ◽  
Content Type

ABSTRACTOxabicyclooctane-linked novel bacterial topoisomerase inhibitors (NBTIs) represent a new class of recently described antibacterial agents with broad-spectrum activity. NBTIs dually inhibit the clinically validated bacterial targets DNA gyrase and topoisomerase IV and have been shown to bind distinctly from known classes of antibacterial agents directed against these targets. Herein we report the molecular, cellular, andin vivocharacterization of AM-8722 as a representative N-alkylated-1,5-naphthyridone left-hand-side-substituted NBTI. Consistent with its mode of action, macromolecular labeling studies revealed a specific effect of AM-8722 to dose dependently inhibit bacterial DNA synthesis. AM-8722 displayed greater intrinsic enzymatic potency than levofloxacin versus both DNA gyrase and topoisomerase IV fromStaphylococcus aureusandEscherichia coliand displayed selectivity against human topoisomerase II. AM-8722 was rapidly bactericidal and exhibited whole-cell activity versus a range of Gram-negative and Gram-positive organisms, with no whole-cell potency shift due to the presence of DNA or human serum. Frequency-of-resistance studies demonstrated an acceptable rate of resistance emergencein vitroat concentrations 16- to 32-fold the MIC. AM-8722 displayed acceptable pharmacokinetic properties and was shown to be efficacious in mouse models of bacterial septicemia. Overall, AM-8722 is a selective and potent NBTI that displays broad-spectrum antimicrobial activityin vitroandin vivo.

scholarly journals The Gut Microbiota-Produced Indole-3-Propionic Acid Confers the Antihyperlipidemic Effect of Mulberry-Derived 1-Deoxynojirimycin

mSystems ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Yougui Li ◽  
Wenyi Xu ◽  
Fang Zhang ◽  
Shi Zhong ◽  
Yuqing Sun ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Propionic Acid ◽  
Theoretical Basis ◽  
Active Component ◽  
Lipid Lowering ◽  
Specific Intervention ◽  
Content Type ◽  
Female Mice

ABSTRACT Hyperlipidemia is a worldwide epidemic with an obvious gender disparity in incidence. Modulations on gut microbiota by traditional Chinese medicines (TCM) are emerging as a potential rationale governing the profitable effects of drugs on hyperlipidemia. However, it is unclear how gut microbes regulate the progression of hyperlipidemia. Here, we found that mulberry leaf extract (MLE) and its active component 1-deoxynojirimycin (DNJ) diminished hyperglycemia and hypertriglyceridemia with similar efficacy in male and female mice but preferentially alleviated hypercholesterolemia in female mice. Further investigations showed that DNJ sex-specifically downregulated the expression of lipogenic genes, especially cholesterol-biosynthetic genes. Oral administration of DNJ imposed more profound modulation on gut microbiota in female mice than in male ones, as estimated by 16S rRNA metatranscriptomic analysis. DNJ markedly enriched Akkermansia and Clostridium group XIVa and promoted the production of indole-3-propionic acid (IPA) in a sexually dimorphic way. Importantly, IPA tightly associates with the antihyperlipidemic effect of DNJ and exhibited a potent lipid-lowering effect both in vitro and in vivo. Together, our results have established a regulatory mechanism by which DNJ sex-specifically improves hyperlipidemia, offering an in-depth theoretical basis for therapeutic exploitation of DNJ as a sex-specific intervention against hyperlipidemia. IMPORTANCE Hyperlipidemia has been intensively focused on by researchers around the world owing to its major contribution to cardiovascular diseases. Various evidence reveals that women are more susceptible than male counterparts to dyslipidemia, making sex-dependent therapeutic strategies and drugs urgently needed. In the present work, we demonstrate that DNJ, the main active component of mulberry leaves, exerts an obvious female-preferential antihyperlipidemic effect through specifically enriching Akkermansia and Clostridium XIVa and elevating an active microbial metabolite, indole-3-propionic acid (IPA), in female mice. Moreover, we have corroborated the potent lipid-lowering efficacy of IPA both in vitro and in vivo. These findings not only indicate a potential mechanism by which gut microbes and their metabolites confer the beneficial role of DNJ in ameliorating hyperlipidemia but also provide an in-depth theoretical basis for therapeutic exploitation of DNJ as a female-specific intervention against hyperlipidemia.

scholarly journals Gut Microbiota Metabolite Indole Propionic Acid Targets Tryptophan Biosynthesis in Mycobacterium tuberculosis

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Dereje Abate Negatu ◽  
Yoshiyuki Yamada ◽  
Yu Xi ◽  
Mei Lin Go ◽  
Matthew Zimmerman ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Gut Microbiota ◽  
Propionic Acid ◽  
De Novo ◽  
Feedback Inhibition ◽  
New Drugs ◽  
Anthranilate Synthase ◽  
Content Type ◽  
Allosteric Inhibitor

ABSTRACT Indole propionic acid (IPA), produced by the gut microbiota, is active against Mycobacterium tuberculosis in vitro and in vivo. However, its mechanism of action is unknown. IPA is the deamination product of tryptophan (Trp) and thus a close structural analog of this essential aromatic amino acid. De novo Trp biosynthesis in M. tuberculosis is regulated through feedback inhibition: Trp acts as an allosteric inhibitor of anthranilate synthase TrpE, which catalyzes the first committed step in the Trp biosynthesis pathway. Hence, we hypothesized that IPA may mimic Trp as an allosteric inhibitor of TrpE and exert its antimicrobial effect by blocking synthesis of Trp at the TrpE catalytic step. To test our hypothesis, we carried out metabolic, chemical rescue, genetic, and biochemical analyses. Treatment of mycobacteria with IPA inhibited growth and reduced the intracellular level of Trp, an effect abrogated upon supplementation of Trp in the medium. Missense mutations at the allosteric Trp binding site of TrpE eliminated Trp inhibition and caused IPA resistance. In conclusion, we have shown that IPA blocks Trp biosynthesis in M. tuberculosis via inhibition of TrpE by mimicking the physiological allosteric inhibitor of this enzyme. IMPORTANCE New drugs against tuberculosis are urgently needed. The tryptophan (Trp) analog indole propionic acid (IPA) is the first antitubercular metabolite produced by human gut bacteria. Here, we show that this antibiotic blocks Trp synthesis, an in vivo essential biosynthetic pathway in M. tuberculosis. Intriguingly, IPA acts by decoupling a bacterial feedback regulatory mechanism: it mimics Trp as allosteric inhibitor of anthranilate synthase, thereby switching off Trp synthesis regardless of intracellular Trp levels. The identification of IPA’s target paves the way for the discovery of more potent TrpE ligands employing rational, target-based lead optimization.

scholarly journals In VitroandIn VivoActivities of Zinc Linolenate, a Selective Antibacterial Agent againstHelicobacter pylori

2019 ◽  
Vol 63 (6) ◽  
Author(s):  
Yanqiang Huang ◽  
Xudong Hang ◽  
Xueqing Jiang ◽  
Liping Zeng ◽  
Jia Jia ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Therapeutic Potential ◽  
Combined Therapy ◽  
Peptic Ulcers ◽  
Current Standard ◽  
Gastric Diseases ◽  
Content Type ◽  
H Pylori

ABSTRACTHelicobacter pyloriis a major global pathogen, and its infection represents a key factor in the etiology of various gastric diseases, including gastritis, peptic ulcers, and gastric carcinoma. The efficacy of current standard treatment forH. pyloriinfection including two broad-spectrum antibiotics is compromised by toxicity toward the gut microbiota and the development of drug resistance, which will likely only be resolved through novel and selective antibacterial strategies. Here, we synthesized a small molecule, zinc linolenate (ZnLla), and investigated its therapeutic potential for the treatment ofH. pyloriinfection. ZnLla showed effective antibacterial activity against standard strains and drug-resistant clinical isolates ofH. pyloriin vitrowith no development of resistance during continuous serial passaging. The mechanisms of ZnLla action againstH. pyloriinvolved the disruption of bacterial cell membranes and generation of reactive oxygen species. In mouse models of multidrug-resistantH. pyloriinfection, ZnLla showedin vivokilling efficacy comparable and superior to the triple therapy approach when use as a monotherapy and a combined therapy with omeprazole, respectively. Moreover, ZnLla treatment induces negligible toxicity against normal tissues and causes minimal effects on both the diversity and composition of the murine gut microbiota. Thus, the high degree of selectivity of ZnLla forH. pyloriprovides an attractive candidate for novel targeted anti-H. pyloritreatment.

scholarly journals Intestinal IgA Regulates Expression of a Fructan Polysaccharide Utilization Locus in Colonizing Gut Commensal Bacteroides thetaiotaomicron

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Payal Joglekar ◽  
Hua Ding ◽  
Pablo Canales-Herrerias ◽  
Pankaj Jay Pasricha ◽  
Justin L. Sonnenburg ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Ex Vivo ◽  
Microbial Colonization ◽  
Bacteroides Thetaiotaomicron ◽  
Content Type ◽  
Microbial Utilization ◽  
Polysaccharide Utilization Locus ◽  
The Impact

ABSTRACT Gut-derived immunoglobulin A (IgA) is the most abundant antibody secreted in the gut that shapes gut microbiota composition and functionality. However, most of the microbial antigens targeted by gut IgA remain unknown, and the functional effects of IgA targeting these antigens are currently understudied. This study provides a framework for identifying and characterizing gut microbiota antigens targeted by gut IgA. We developed a small intestinal ex vivo culture assay to harvest lamina propria IgA from gnotobiotic mice, with the aim of identifying antigenic targets in a model human gut commensal, Bacteroides thetaiotaomicron VPI-5482. Colonization by B. thetaiotaomicron induced a microbe-specific IgA response that was reactive against diverse antigens, including capsular polysaccharides, lipopolysaccharides, and proteins. IgA against microbial protein antigens targeted membrane and secreted proteins with diverse functionalities, including an IgA specific against proteins of the polysaccharide utilization locus (PUL) that are necessary for utilization of fructan, which is an important dietary polysaccharide. Further analyses demonstrated that the presence of dietary fructan increased the production of fructan PUL-specific IgA, which then downregulated the expression of fructan PUL in B. thetaiotaomicron, both in vivo and in vitro. Since the expression of fructan PUL has been associated with the ability of B. thetaiotaomicron to colonize the gut in the presence of dietary fructans, our work suggests a novel role for gut IgA in regulating microbial colonization by modulating their metabolism. IMPORTANCE Given the significant impact that gut microbes have on our health, it is essential to identify key host and environmental factors that shape this diverse community. While many studies have highlighted the impact of diet on gut microbiota, little is known about how the host regulates this critical diet-microbiota interaction. In our present study, we discovered that gut IgA targeted a protein complex involved in the utilization of an important dietary polysaccharide: fructan. While the presence of dietary fructans was previously thought to allow unrestricted growth of fructan-utilizing bacteria, our work shows that gut IgA, by targeting proteins responsible for fructan utilization, provides the host with tools that can restrict the microbial utilization of such polysaccharides, thereby controlling their growth.

scholarly journals Mode of Action of Clofazimine and Combination Therapy with Benzothiazinones against Mycobacterium tuberculosis

2015 ◽  
Vol 59 (8) ◽  
pp. 4457-4463 ◽  
Author(s):  
Benoit Lechartier ◽  
Stewart T. Cole
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Bacterial Load ◽  
Multidrug Resistant ◽  
Content Type ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Drug Resistant Strains ◽  
Transfer Chain

ABSTRACTClofazimine (CZM) is an antileprosy drug that was recently repurposed for treatment of multidrug-resistant tuberculosis. InMycobacterium tuberculosis, CZM appears to act as a prodrug, which is reduced by NADH dehydrogenase (NDH-2), to release reactive oxygen species upon reoxidation by O2. CZM presumably competes with menaquinone (MK-4), a key cofactor in the mycobacterial electron transfer chain, for its reduction by NDH-2. We studied the effect of MK-4 supplementation on the activity of CZM againstM. tuberculosisand found direct competition between CZM and MK-4 for the cidal effect of CZM, against nonreplicating and actively growing bacteria, as MK-4 supplementation blocked the drug's activity against nonreplicating bacteria. We demonstrated that CZM, like bedaquiline, is synergisticin vitrowith benzothiazinones such as 2-piperazino-benzothiazinone 169 (PBTZ169), and this synergy also occurs against nonreplicating bacteria. The synergy between CZM and PBTZ169 was lost in an MK-4-rich medium, indicating that MK-4 is the probable link between their activities. The efficacy of the dual combination of CZM and PBTZ169 was testedin vivo, where a great reduction in bacterial load was obtained in a murine model of chronic tuberculosis. Taken together, these data confirm the potential of CZM in association with PBTZ169 as the basis for a new regimen against drug-resistant strains ofM. tuberculosis.

Effects of food additives on gut microbiota: friend or foe?

2019 ◽  
Vol 49 (5) ◽  
pp. 955-964
Author(s):  
Elif Inan-Eroglu ◽  
Aylin Ayaz
Keyword(s):  
Gut Microbiota ◽  
Food Additives ◽  
Experimental Studies ◽  
Metabolic Effects ◽  
Artificial Sweeteners ◽  
Processed Foods ◽  
Dietary Interventions ◽  
Content Type ◽  
Model Studies

PurposeRecent evidence suggests that especially processed foods may lead to undesirable metabolic effects in gut microbiota. The emulsifiers and artificial sweeteners that are added to processed foods may play a role in the progression of the diseases through the modulation of microbiota in mice. In this context, the purpose of this paper is to evaluate the effects of emulsifiers and artificial sweeteners.Design/methodology/approachThis paper presents a narrative review of the effects of emulsifiers and artificial sweeteners which are mainly in consumed in the Western diet, to the gut microbiota by mainly focusing on the experimental studies.FindingsAlthoughin vivostudies and animal model studies showed various adverse effects of sweeteners and emulsifiers to microbiota, studies should be conducted in humans to investigate the effects of these food additives to human microbiota by making dietary interventions in the context of ethical rules.Originality/valueIn future, studies will allow us to draw more definitive conclusion whether human population consuming sweeteners and emulsifiers are at risk.

scholarly journals AR-12 Exhibits Direct and Host-Targeted Antibacterial Activity toward Mycobacterium abscessus

2020 ◽  
Vol 64 (8) ◽  
Author(s):  
Shaoyan Zhang ◽  
Yuzhen Zou ◽  
Qi Guo ◽  
Jianhui Chen ◽  
Liyun Xu ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Minimum Bactericidal Concentration ◽  
Bacterial Load ◽  
Mycobacterium Abscessus ◽  
Potential Candidate ◽  
Content Type ◽  
Repurposed Drugs ◽  
Time Kill

ABSTRACT Therapeutic options for Mycobacterium abscessus infections are extremely limited. New or repurposed drugs are needed. The anti-M. abscessus activity of AR-12 (OSU-03012), reported to express broad-spectrum antimicrobial effects, was investigated in vitro and in vivo. Antimicrobial susceptibility testing was performed on 194 clinical isolates. Minimum bactericidal concentration and time-kill kinetics assays were conducted to distinguish the bactericidal versus bacteriostatic activity of AR-12. Synergy between AR-12 and five clinically important antibiotics was determined using a checkerboard synergy assay. The activity of AR-12 against intracellular M. abscessus residing within macrophage was also evaluated. Finally, the potency of AR-12 in vivo was determined in a neutropenic mouse model that mimics pulmonary M. abscessus infection. AR-12 exhibited high anti-M. abscessus activity in vitro, with an MIC50 of 4 mg/liter (8.7 μM) and an MIC90 of 8 mg/liter (17.4 μM) for both subsp. abscessus and subsp. massiliense. AR-12 and amikacin exhibited comparable bactericidal activity against extracellular M. abscessus in culture. AR-12, however, exhibited significantly greater intracellular antibacterial activity than amikacin and caused a significant reduction in the bacterial load in the lungs of neutropenic mice infected with M. abscessus. No antagonism between AR-12 and clarithromycin, amikacin, imipenem, cefoxitin, or tigecycline was evident. In conclusion, AR-12 is active against M. abscessus in vitro and in vivo and does not antagonize the most frequently used anti-M. abscessus drugs. As such, AR-12 is a potential candidate to include in novel strategies to treat M. abscessus infections.

scholarly journals Effect of Dietary Oxalate on the Gut Microbiota of the Mammalian Herbivore Neotoma albigula

2016 ◽  
Vol 82 (9) ◽  
pp. 2669-2675 ◽  
Author(s):  
Aaron W. Miller ◽  
Kelly F. Oakeson ◽  
Colin Dale ◽  
M. Denise Dearing
Keyword(s):  
Gut Microbiota ◽  
High Throughput Sequencing ◽  
Fecal Microbiota ◽  
Content Type ◽  
Form And Function ◽  
Plant Secondary Compound ◽  
Mammalian Herbivore ◽  
And Function ◽  
Dietary Oxalate

ABSTRACTDiet is one of the primary drivers that sculpts the form and function of the mammalian gut microbiota. However, the enormous taxonomic and metabolic diversity held within the gut microbiota makes it difficult to isolate specific diet-microbe interactions. The objective of the current study was to elucidate interactions between the gut microbiota of the mammalian herbivoreNeotoma albigulaand dietary oxalate, a plant secondary compound (PSC) degraded exclusively by the gut microbiota. We quantified oxalate degradation inN. albigulafed increasing amounts of oxalate over time and tracked the response of the fecal microbiota using high-throughput sequencing. The amount of oxalate degradedin vivowas linearly correlated with the amount of oxalate consumed. The addition of dietary oxalate was found to impact microbial species diversity by increasing the representation of certain taxa, some of which are known to be capable of degrading oxalate (e.g.,Oxalobacterspp.). Furthermore, the relative abundances of 117 operational taxonomic units (OTU) exhibited a significant correlation with oxalate consumption. The results of this study indicate that dietary oxalate induces complex interactions within the gut microbiota that include an increase in the relative abundance of a community of bacteria that may contribute either directly or indirectly to oxalate degradation in mammalian herbivores.

scholarly journals Vaginal Gel Component Hydroxyethyl Cellulose Significantly Enhances the Infectivity ofChlamydia trachomatisSerovars D and E

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Tímea Raffai ◽  
Katalin Burián ◽  
László Janovák ◽  
Anita Bogdanov ◽  
Johannes H. Hegemann ◽  
...  
Keyword(s):  
Fold Increase ◽  
Hydroxyethyl Cellulose ◽  
Gelling Agent ◽  
Maximal Increase ◽  
Content Type ◽  
Enhancing Effect ◽  
Vaginal Gels ◽  
Dependent Growth

ABSTRACTThe transmission of the urogenital serovars ofChlamydia trachomatiscan be significantly influenced by vaginal gels. Hydroxyethyl cellulose is a commonly used gelling agent that can be found in vaginal gels. Hydroxyethyl cellulose showed a concentration-dependent growth-enhancing effect onC. trachomatisserovars D and E, with a 26.1-fold maximal increasein vitroand a 2.57-fold increasein vivo.

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