Metabolomics analysis of the lactobacillus plantarum ATCC 14917 response to antibiotic stress.

BACKGROUND: Lactobacillus plantarum has been found to play a significant role in maintaining the balance of intestinal flora in the human gut. However, it is sensitive to commonly used antibiotics and is often incidentally killed during treatment. We attempted to identify a means to protect L. plantarum ATCC14917 from the metabolic changes caused by two commonly used antibiotics, ampicillin, and doxycycline. We examined the metabolic changes under ampicillin and doxycycline treatment and assessed the protective effects of adding key exogenous metabolites. RESULTS: Using metabolomics, we found that under the stress of ampicillin or doxycycline, L. plantarum ATCC14917 exhibited reduced metabolic activity, with purine metabolism a key metabolic pathway involved in this change. We then screened the key biomarkers in this metabolic pathway, guanine and adenosine diphosphate (ADP). The exogenous addition of each of these two metabolites significantly reduced the lethality of ampicillin and doxycycline on L. plantarum ATCC14917. Because purine metabolism is closely related to the production of reactive oxygen species (ROS), the results showed that the addition of guanine or ADP reduced intracellular ROS levels in L. plantarum ATCC14917. Moreover, the killing effects of ampicillin and doxycycline on L. plantarum ATCC14917 were restored by the addition of a ROS accelerator in the presence of guanine or ADP. CONCLUSIONS: The metabolic changes of L. plantarum ATCC14917 under antibiotic treatments were determined. Moreover, the metabolome information that was elucidated can be used to help L. plantarum cope with adverse stress, which will help probiotics become less vulnerable to antibiotics during clinical treatment.

Exogenous NADH promotes the bactericidal effect of aminoglycoside antibiotics against Edwardsiella tarda.

The global surge in multidrug-resistant bacteria owing to antibiotic misuse and overuse poses considerable risks to human and animal health. With existing antibiotics losing their effectiveness and the protracted process of developing new antibiotics, urgent alternatives are imperative to curb disease spread. Notably, improving the bactericidal effect of antibiotics by using non-antibiotic substances has emerged as a viable strategy. Although reduced nicotinamide adenine dinucleotide (NADH) may play a crucial role in regulating bacterial resistance, studies examining how the change of metabolic profile and bacterial resistance following by exogenous administration are scarce. Therefore, this study aimed to elucidate the metabolic changes that occur in Edwardsiella tarda (E. tarda), which exhibits resistance to various antibiotics, following the exogenous addition of NADH using metabolomics. The effects of these alterations on the bactericidal activity of neomycin were investigated. NADH enhanced the effectiveness of aminoglycoside antibiotics against E. tarda ATCC15947, achieving bacterial eradication at low doses. Metabolomic analysis revealed that NADH reprogrammed the ATCC15947 metabolic profile by promoting purine metabolism and energy metabolism, yielding increased adenosine triphosphate (ATP) levels. Increased ATP levels played a crucial role in enhancing the bactericidal effects of neomycin. Moreover, exogenous NADH promoted the bactericidal efficacy of tetracyclines and chloramphenicols. NADH in combination with neomycin was effective against other clinically resistant bacteria, including Aeromonas hydrophila, Vibrio parahaemolyticus, methicillin-resistant Staphylococcus aureus, and Listeria monocytogenes. These results may facilitate the development of effective approaches for preventing and managing E. tarda-induced infections and multidrug resistance in aquaculture and clinical settings.

L-glutamine sensitizes Gram-positive-resistant bacteria to gentamicin killing.

IMPORTANCE: Methicillin-resistant Staphylococcus aureus (MRSA) infection severely threatens human health due to high morbidity and mortality; it is urgent to develop novel strategies to tackle this problem. Metabolites belong to antibiotic adjuvants which improve the effect of antibiotics. Despite reports of L-glutamine being applied in antibiotic adjuvant for Gram-negative bacteria, how L-glutamine affects antibiotics against Gram-positive-resistant bacteria is still unclear. In this study, L-glutamine increases the antibacterial effect of gentamicin on MRSA, and it links to membrane permeability and pH gradient (ΔpH), resulting in uptake of more gentamicin. Of great interest, reduced reactive oxygen species (ROS) by glutathione was found under L-glutamine treatment; USA300 becomes sensitive again to gentamicin. This study not only offers deep understanding on ΔpH and ROS on bacterial resistance but also provides potential treatment solutions for targeting MRSA infection.

Effect of Three Different Amino Acids Plus Gentamicin Against Methicillin-Resistant Staphylococcus aureus.

Background: The issue of methicillin-resistant Staphylococcus aureus (MRSA) resistant to many antibiotics and causing serious infectious diseases is a growing healthcare concern. Purpose: In recent years, exogenous administration of metabolites in combination with antibiotics can re-sensitize resistant bacteria to antibiotics; however, their effects vary, and their underlying mechanism of action remains elusive. Methods: We assessed the bactericidal effects of the three amino acids in combination with gentamicin in vitro and in vivo. Subsequently, we explored the role of these amino acids on the metabolomics of MRSA using Liquid chromatography-tandem mass spectrometry (LC-MS/MS). Furthermore, we performed the downstream analyses using MetaboAnalyst and Interactive Pathways Explorer. Results: Exogenous threonine showed the best bactericidal efficacy with gentamicin, followed by glycine, wherein serine had no effect. Amino acid treatments mainly up-regulated the metabolites, increased the amino acid abundance, and significantly activated metabolisms; these effects were consistent with the bactericidal efficacy of the three amino acids. Most amino acids participated in the tricarboxylic acid cycle, and threonine supplementation increased the activities of citrate synthase, isocitrate dehydrogenase and α-ketoglutarate dehydrogenase, whereas glycine increased activities of citrate synthase and α-ketoglutarate dehydrogenase, and serine did not affect the activities of any of the three key enzymes. We identified 24 biomarkers in the three groups, among which glutamic acid and cysteine showed a gradient decrease and increase, respectively. Subsequent analyses revealed that glutamic acid but not cysteine promoted the bactericidal effect of gentamicin synergistically. Conclusion: Threonine has the best synergistic effect in reversing bacterial resistance compared to glycine and serine. We show that different amino acids combined with an antibiotic mainly affect amino acid metabolism and act via different metabolic regulatory mechanisms, which could help develop effective strategies for tackling MRSA infections.

Gentamicin resistance to Escherichia coli related to fatty acid metabolism based on transcriptome analysis.

Antibiotic overuse and misuse have promoted the emergence and spread of antibiotic-resistant bacteria. Increasing bacterial resistance to antibiotics is a major healthcare problem, necessitating elucidation of antibiotic resistance mechanisms. In this study, we explored the mechanism of gentamicin resistance by comparing the transcriptomes of antibiotic-sensitive and -resistant Escherichia coli. A total of 410 differentially expressed genes were identified, of which 233 (56.83%) were up-regulated and 177 (43.17%) were down-regulated in the resistant strain compared with the sensitive strain. Gene Ontology (GO) analysis classifies differential gene expression into three main categories: biological processes, cellular components, and molecular functions. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that the up-regulated genes were enriched in eight metabolic pathways, including fatty acid metabolism, which suggests that fatty acid metabolism may be involved in the development of gentamicin resistance in E. coli. This was demonstrated by measuring the acetyl-CoA carboxylase activity, plays a fundamental role in fatty acid metabolism, was increased in gentamicin-resistant E. coli. Treatment of fatty acid synthesis inhibitor, triclosan, promoted gentamicin-mediated killing efficacy to antibiotic-resistant bacteria. We also found that exogenous addition of oleic acid, which involved in fatty acid metabolism, reduced E. coli sensitivity to gentamicin. Overall, our results provide insight into the molecular mechanism of gentamicin resistance development in E. coli.

Jasminoidin and ursodeoxycholic acid exert synergistic effect against cerebral ischemia-reperfusion injury via Dectin-1-induced NF-κB activation pathway.

BACKGROUND: Jasminoidin (JA) and ursodeoxycholic acid (UA) were shown to act synergistically against ischemic stroke (IS) in our previous studies. PURPOSE: To investigate the holistic synergistic mechanism of JA and UA on cerebral ischemia. METHODS: Middle cerebral artery obstruction reperfusion (MCAO/R) mice were used to evaluate the efficacy of JA, UA, and JA combined with UA (JU) using neurological function testing and infarct volume examination. High-throughput RNA-seq combined with computational prediction and function-integrated analysis was conducted to gain insight into the comprehensive mechanism of synergy. The core mechanism was validated using western blotting. RESULTS: JA and UA synergistically reduced cerebral infarct volume and alleviated neurological deficits and pathological changes in MCAO/R mice. A total of 1437, 396, 1080, and 987 differentially expressed genes were identified in the vehicle, JA, UA, and JU groups, respectively. A strong synergistic effect between JA and UA was predicted using chemical similarity analysis, target profile comparison, and semantic similarity analysis. As the 'long-tail' drugs, the top 20 gene ontology (GO) biological processes of JA, UA, and JU groups primarily reflected inflammatory response and regulation of cytokine production, with specific GO terms of JU revealing enhanced regulation on immune response and tumor necrosis factor superfamily cytokine production. Comparably, the Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling of common targets of JA, UA, and JU focused on extracellular matrix organization and signaling by interleukins, immune system, phagosomes, and lysosomes, which interlock and interweave to produce the synergistic effects of JU. The characteristic signaling pathway identified for JU highlighted the crosstalk between autophagy activation and inflammatory pathways, especially the Dectin-1-induced NF-κB activation pathway, which was validated by in vivo experiments. CONCLUSIONS: JA and UA can synergistically protect cerebral ischemia-reperfusion injury by attenuating Dectin-1-induced NF-κB activation. The strategy integrating high throughput data with computational models enables ever-finer mapping of 'long-tail' drugs to dynamic variations in condition-specific omics to clarify synergistic mechanisms.

Quantitative proteomics reveals reduction in central carbon and energy metabolisms contributes to gentamicin resistance in Staphylococcus aureus.

The emergence of antibiotic resistance greatly increases the difficulty of treating bacterial infections. In order to develop effective treatments, the underlying mechanisms of antibiotic resistance must be understood. In this study, Staphylococcus aureus ATCC6538 strain was passaged in medium with and without gentamicin and obtained lab-evolved gentamicin-resistant S. aureus (RGEN) and gentamicin-sensitive S. aureus (SGEN) strains, respectively. Data-Independent Acquisition (DIA)-based proteomics approach was applied to compare the two strains. A total of 1426 proteins were identified, of which 462 were significantly different: 126 were upregulated and 336 were downregulated in RGEN compared to SGEN. Further analysis found that reduced protein biosynthesis was a characteristic feature in RGEN, related to metabolic suppression. The most differentially expressed proteins were involved in metabolic pathways. In RGEN, central carbon metabolism was dysregulated and energy metabolism decreased. After verification, it was found that the levels of NADH, ATP, and reactive oxygen species (ROS) decreased, and superoxide dismutase and catalase activities increased. These findings suggest that inhibition of central carbon and energy metabolic pathways may play an important role in the resistance of S. aureus to gentamicin, and that gentamicin resistance is associated with oxidative stress. Significance: The overuse and misuse of antibiotics have led to bacterial antibiotic resistance, which is a serious threat to human health. Understanding the mechanisms of antibiotic resistance will help better control these antibiotic-resistant pathogens in the future. The present study characterized the differential proteome of gentamicin-resistant Staphylococcus aureus using the most advanced DIA-based proteomics technology. Many of the differential expressed proteins were related to metabolism, specifically, reduced central carbon and energy metabolism. Lower levels of NADH, ROS, and ATP were detected as a consequence of the reduced metabolism. These results reveal that downregulation of protein expression affecting central carbon and energy metabolisms may play an important role in the resistance of S. aureus to gentamicin.

Uracil restores susceptibility of methicillin-resistant Staphylococcus aureus to aminoglycosides through metabolic reprogramming.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) has now become a major nosocomial pathogen bacteria and resistant to many antibiotics. Therefore, Development of novel approaches to combat the disease is especially important. The present study aimed to provide a novel approach involving the use of nucleotide-mediated metabolic reprogramming to tackle intractable methicillin-resistant S. aureus (MRSA) infections. Objective: This study aims to explore the bacterial effects and mechanism of uracil and gentamicin in S. aureus. Methods: Antibiotic bactericidal assays was used to determine the synergistic bactericidal effect of uracil and gentamicin. How did uracil regulate bacterial metabolism including the tricarboxylic acid (TCA) cycle by GC-MS-based metabolomics. Next, genes and activity of key enzymes in the TCA cycle, PMF, and intracellular aminoglycosides were measured. Finally, bacterial respiration, reactive oxygen species (ROS), and ATP levels were also assayed in this study. Results: In the present study, we found that uracil could synergize with aminoglycosides to kill MRSA (USA300) by 400-fold. Reprogramming metabolomics displayed uracil reprogrammed bacterial metabolism, especially enhanced the TCA cycle to elevate NADH production and proton motive force, thereby promoting the uptake of antibiotics. Furthermore, uracil increased cellular respiration and ATP production, resulting the generation of ROS. Thus, the combined activity of uracil and antibiotics induced bacterial death. Inhibition of the TCA cycle or ROS production could attenuate bactericidal efficiency. Moreover, uracil exhibited bactericidal activity in cooperation with aminoglycosides against other pathogenic bacteria. In a mouse mode of MRSA infection, the combination of gentamicin and uracil increased the survival rate of infected mice. Conclusion: Our results suggest that uracil enhances the activity of bactericidal antibiotics to kill Gram-positive bacteria by modulating bacterial metabolism.

Traditional Chinese medicine for transformation of gastric precancerous lesions to gastric cancer: A critical review.

Gastric cancer (GC) is a common gastrointestinal tumor. Gastric precancerous lesions (GPL) are the last pathological stage before normal gastric mucosa transforms into GC. However, preventing the transformation from GPL to GC remains a challenge. Traditional Chinese medicine (TCM) has been used to treat gastric disease for millennia. A series of TCM formulas and active compounds have shown therapeutic effects in both GC and GPL. This article reviews recent progress on the herbal drugs and pharmacological mechanisms of TCM in preventing the transformation from GPL to GC, especially focusing on anti-inflammatory, anti-angiogenesis, proliferation, and apoptosis. This review may provide a meaningful reference for the prevention of the transformation from GPL to GC using TCM.

Acupuncture for radiotherapy-induced nausea and vomiting: A systematic review protocol.

BACKGROUND: Assessing the effectiveness and safety of acupuncture therapy for treating patients with radiotherapy-induced nausea and vomiting (RINV) is the main purpose of this systematic review protocol. METHODS: The following electronic databases will be searched from inception to Sep 2019: Cochrane Central Register of Controlled Trials, PubMed, Web of Science, EMBASE, China National Knowledge Infrastructure, Traditional Chinese Medicine, Chinese Biomedical Literature Database, Wan-Fang Database, and Chinese Scientific Journal Database. All published randomized controlled trials in English or Chinese related to acupuncture for RINV will be included. The primary outcome is the severity and frequency of RINV during radiotherapy. The secondary outcomes is the physical condition and quality of life after radiotherapy. Two reviewers will conduct the study selection, data extraction, and assessment independently. The assessment of risk of bias and data synthesis will be conducted with Review Manager Software V.5.2. RESULTS: The results will provide a high-quality synthesis of current evidence for researchers in this subject area. CONCLUSION: The conclusion of our study will provide evidence to judge whether acupuncture is an effective intervention for patients suffered from RINV. PROSPERO REGISTRATION NUMBER: CRD42019130952.

Protective action of aspirin and its against endothelial Nlrp3 inflammasome activation in response to LPS stimuli / 中国药理学与毒理学杂志

OBJECTIVE Recent studies have demonstrated that the Nlrp3 inflammasome serve as a central role in the pathogenesis of cardiovascular diseases and endothelial dysfunction occurs in association with several cardiovascular risk factors. Given the demonstrated anti-inflammatory effects of aspirin, the present study was designed to test whether aspirin diminish NLRP3 inflammasome activation and prevent endothelium injury and associated coronary artery damage during LPS. METHODS Mouse carotid arterial endothelial cells (CAECs) were cultured and treated with 0.1-3 mmol·L-1 of aspirin in response to LPS (2 μg·mL-1) stimuli. After 24 h, the Nlrp3 inflammasome complexes consist of varied proteins were analyzed by WB. NO and T-AOC in the supernatant was detected by ELISA. Intracellular reactive oxygen species (ROS) generation for 24 h was observed by DCF fluorescence. The mice were treated with aspirin (12.5 mg·kg-1 per day, 62.5 mg·kg-1 per day, 125 mg·kg-1 per day) and dexametha?sone (0.0182 mg · kg- 1 per day) for 7 d. The level of IL- 1β,IL- 18 protein was detected by ELISA. RESULTS Immunofluorescence results showed the colocalization of Nlrp3 with ASC or caspase 1 decrease in a concentration- dependent manner. Meanwhile, the expression of Nlrp3 and caspase 1 protein was decreased with the concentration of aspirin, but no changes the expression of ASC protein. Nlrp3 protein levels in CAECs were 0.33- 0.8- fold and cle- caspase 1 protein levels in CAECs were 0.48-1-fold compared to those in LPS stimulation when treated with 0.1-3 mmol·L-1 aspirin for 24 h (P<0.01). Aspirin significantly antagonized the effect of LPS on NO (1.22-1.91-fold that of LPS stimulation, P<0.01) and T-AOC expression (1.02-1.90-fold that of LPS stimulation, P<0.01). As the different concentration of aspirin treated, the generation of ROS was 0.51-1.10-fold that of LPS stimulation (P<0.01). In vivo data shown the level of IL-1β, IL-18 protein from serum are in concordance with the level of Nlrp3 inflammasome activation. CONCLUSION We conclude that aspirin has anti- inflammatory properties, protecting CAECs from LPS-induced injury by inhibition of NLRP3 inflammasome activation through ROS pathway.

[Reconstruction of the medial collateral ligament of elbow].

OBJECTIVE: To evaluate the clinical effect of excising the radial head, repairing or reconstructing the medial collateral ligament (MCL) in treating comminuted fracture of the radial head accompanying by MCL injury. METHODS: From September 2000 to April 2006, 18 patients with comminuted fractures of radial head accompanying by MCL injury were treated by excision of the radial head, repair or reconstruction of the MCL. Of them, there were 12 males and 6 females, aged 21 to 57 years. Injury was caused by high falling in 10 cases and by traffic accidents in 8 cases. According to Mason classifications, 13 fractures were of type III and 5 of type IV. Fifteen cases of fresh fractures were operated within 2 weeks, 3 cases of old fractures at 4, 6, and 14 months after injury respectively. Four cases underwent MCL repair and 14 cases underwent MCL reconstruction. RESULTS: All the 18 cases were followed up 1-5 years (mean 3 years). According to Broberg and Morrey scoring system, 4 patients were rated as excellent, 12 as good, 1 as fair, and 1 as poor. The excellent and good rate was 88.9%. Three patients had light pain of elbow, 1 patient had moderate pain and the other 14 had no pain. The range of elbow motion was from 110 to 140 degrees (mean 130 degrees). The pronation averaged 75 degrees (35-85 degrees). The supination averaged 80 degrees (65-89 degrees). Compared with normal limbs, the grip strength decreased by 3% to 28% (mean 15%); the extension strength decreased by 8% to 39% (mean 30%); the flexion strength decreased by 7% to 29% (mean 18%); the pronation strength decreased by 7% to 31% (mean 20%); the supination strength decreased by 15% to 45% (mean 25%). The X-ray films showed that carrying angle increased by 0 to 11 degrees (mean 5 degrees) under two-newton-meter valgus torque. There were significant differences between injured limbs and normal limbs (P < 0.05). CONCLUSION: The MCL was the primary valgus stabilizer of the elbow. If the radial head replacement could not be carried out, the repair or reconstruction of the medial collateral ligament was effective.

[Biomechanical evaluation of the valgus stability of elbow after reconstruction].

OBJECTIVE: To evaluate of the valgus stability of the elbow after excision of the radial head, release of the medial collateral ligament (MCL), radial head replacement, and medial collateral ligament reconstruction. METHODS: Twelve fresh human cadaveric elbows were dissected to establish 7 kinds of specimens with elbow joint and ligaments as follow: (1) intact (n=12); (2) release of the medial collateral ligament (n=6); (3) excision of the radial head (n=6); (4) excision of the radial head together with release of the medial collateral ligament (n=12); (5) radial head replacement (n=6); (6) medial collateral ligament reconstruction (n=6); (7) radial head replacement together with medial collateral ligament reconstruction (n=12). Under two-newton-meter valgus torque, and at 0, 30, 60, 90 and 120 degrees of flexion with the forearm in supination, the valgus elbow laxity was quantified: All analysis was performed with SPSS 10.0 software. RESULTS: The least valgus laxity was seen in the intact state and its stability was the best. The laxity increased after resection of the radial head. The laxity was more after release of the medial collateral ligament than after resection of the radial head (P<0.01). The greatest laxity was observed after release of the medial collateral ligament together with resection of the radial head, so its stability was the worst. The laxity of the following implant of the radial head decreased. The laxity of the medial collateral ligament reconstruction was as much as that of the intact ligament (P>0.05). The laxity of the radial head replacement together with medial collateral ligament reconstruction became less. CONCLUSION: The results of this study show that the medial collateral ligament is the primary valgus stabilizer of the elbow and the radial head was a secondary constraint to resist valgus laxity. Both the medial collateral ligament reconstruction and the radial head replacement can restore the stability of elbow. If the radial head replacement can not be carried out, the reconstruction of the medial collateral ligament is acceptable.