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BMC Microbiology May 2024Urinary tract infections (UTIs) are common bacterial infections, primarily caused by uropathogenic Escherichia coli (UPEC), leading to significant health issues and...
BACKGROUND
Urinary tract infections (UTIs) are common bacterial infections, primarily caused by uropathogenic Escherichia coli (UPEC), leading to significant health issues and economic burden. Although antibiotics have been effective in treating UPEC infections, the rise of antibiotic-resistant strains hinders their efficacy. Hence, identifying novel bacterial targets for new antimicrobial approaches is crucial. Bacterial factors required for maintaining the full virulence of UPEC are the potential target. MepM, an endopeptidase in E. coli, is involved in the biogenesis of peptidoglycan, a major structure of bacterial envelope. Given that the bacterial envelope confronts the hostile host environment during infections, MepM's function could be crucial for UPEC's virulence. This study aims to explore the role of MepM in UPEC pathogenesis.
RESULTS
MepM deficiency significantly impacted UPEC's survival in urine and within macrophages. Moreover, the deficiency hindered the bacillary-to-filamentous shape switch which is known for aiding UPEC in evading phagocytosis during infections. Additionally, UPEC motility was downregulated due to MepM deficiency. As a result, the mepM mutant displayed notably reduced fitness in causing UTIs in the mouse model compared to wild-type UPEC.
CONCLUSIONS
This study provides the first evidence of the vital role of peptidoglycan endopeptidase MepM in UPEC's full virulence for causing UTIs. MepM's contribution to UPEC pathogenesis may stem from its critical role in maintaining the ability to resist urine- and immune cell-mediated killing, facilitating the morphological switch, and sustaining motility. Thus, MepM is a promising candidate target for novel antimicrobial strategies.
Topics: Urinary Tract Infections; Uropathogenic Escherichia coli; Animals; Mice; Escherichia coli Infections; Virulence; Endopeptidases; Escherichia coli Proteins; Female; Peptidoglycan; Macrophages; Humans; Disease Models, Animal
PubMed: 38816687
DOI: 10.1186/s12866-024-03290-9 -
PLoS Biology May 2024The peptidoglycan (PG) layer is a critical component of the bacterial cell wall and serves as an important target for antibiotics in both gram-negative and gram-positive...
The peptidoglycan (PG) layer is a critical component of the bacterial cell wall and serves as an important target for antibiotics in both gram-negative and gram-positive bacteria. The hydrolysis of septal PG (sPG) is a crucial step of bacterial cell division, facilitated by FtsEX through an amidase activation system. In this study, we present the cryo-EM structures of Escherichia coli FtsEX and FtsEX-EnvC in the ATP-bound state at resolutions of 3.05 Å and 3.11 Å, respectively. Our PG degradation assays in E. coli reveal that the ATP-bound conformation of FtsEX activates sPG hydrolysis of EnvC-AmiB, whereas EnvC-AmiB alone exhibits autoinhibition. Structural analyses indicate that ATP binding induces conformational changes in FtsEX-EnvC, leading to significant differences from the apo state. Furthermore, PG degradation assays of AmiB mutants confirm that the regulation of AmiB by FtsEX-EnvC is achieved through the interaction between EnvC-AmiB. These findings not only provide structural insight into the mechanism of sPG hydrolysis and bacterial cell division, but also have implications for the development of novel therapeutics targeting drug-resistant bacteria.
Topics: Peptidoglycan; Cell Division; Hydrolysis; Escherichia coli Proteins; Escherichia coli; Adenosine Triphosphate; Cryoelectron Microscopy; Cell Wall; Protein Conformation; Models, Molecular; N-Acetylmuramoyl-L-alanine Amidase; Bacterial Outer Membrane Proteins; ATP-Binding Cassette Transporters; Cystic Fibrosis Transmembrane Conductance Regulator; Lipoproteins; Cell Cycle Proteins
PubMed: 38814940
DOI: 10.1371/journal.pbio.3002628 -
Journal of Bacteriology Jun 2024Reducing growth and limiting metabolism are strategies that allow bacteria to survive exposure to environmental stress and antibiotics. During infection, uropathogenic...
UNLABELLED
Reducing growth and limiting metabolism are strategies that allow bacteria to survive exposure to environmental stress and antibiotics. During infection, uropathogenic (UPEC) may enter a quiescent state that enables them to reemerge after the completion of successful antibiotic treatment. Many clinical isolates, including the well-characterized UPEC strain CFT073, also enter a metabolite-dependent, quiescent state that is reversible with cues, including peptidoglycan-derived peptides and amino acids. Here, we show that quiescent UPEC is antibiotic tolerant and demonstrate that metabolic flux in the tricarboxylic acid (TCA) cycle regulates the UPEC quiescent state via succinyl-CoA. We also demonstrate that the transcriptional regulator complex integration host factor and the FtsZ-interacting protein ZapE, which is important for division during stress, are essential for UPEC to enter the quiescent state. Notably, in addition to engaging FtsZ and late-stage cell division proteins, ZapE also interacts directly with TCA cycle enzymes in bacterial two-hybrid assays. We report direct interactions between the succinate dehydrogenase complex subunit SdhC, the late-stage cell division protein FtsN, and ZapE. These interactions may enable communication between oxidative metabolism and the cell division machinery in UPEC. Moreover, these interactions are conserved in an K-12 strain. This work suggests that there is coordination among the two fundamental and essential pathways that regulate overall growth, quiescence, and antibiotic susceptibility.
IMPORTANCE
Uropathogenic (UPEC) are the leading cause of urinary tract infections (UTIs). Upon invasion into bladder epithelial cells, UPEC establish quiescent intracellular reservoirs that may lead to antibiotic tolerance and recurrent UTIs. Here, we demonstrate using an system that quiescent UPEC cells are tolerant to ampicillin and have decreased metabolism characterized by succinyl-CoA limitation. We identify the global regulator integration host factor complex and the cell division protein ZapE as critical modifiers of quiescence and antibiotic tolerance. Finally, we show that ZapE interacts with components of both the cell division machinery and the tricarboxylic acid cycle, and this interaction is conserved in non-pathogenic , establishing a novel link between cell division and metabolism.
Topics: Uropathogenic Escherichia coli; Anti-Bacterial Agents; Escherichia coli Proteins; Citric Acid Cycle; Gene Expression Regulation, Bacterial; Bacterial Proteins; Drug Resistance, Bacterial; Escherichia coli Infections
PubMed: 38814092
DOI: 10.1128/jb.00162-24 -
International Journal of Antimicrobial... May 2024Clostridioides difficile has emerged as a major cause of life-threatening diarrheal disease. Conventional antibiotics used in current standards of care exacerbate the...
OBJECTIVES
Clostridioides difficile has emerged as a major cause of life-threatening diarrheal disease. Conventional antibiotics used in current standards of care exacerbate the emergence of antibiotic-resistant strains and pose a risk of recurrent C. difficile infection (CDI). Thus, there is an urgent need for alternative therapeutics that selectively eliminate C. difficile without disturbing the commensal microbiota. This study aimed to explore the potential of endolysins as an alternative therapeutic agent to antibiotics. Endolysin is a bacteriophage-derived peptidoglycan hydrolase that aids in the release of phage progeny during the final stage of infection.
METHODS
In order to exploit endolysin as a therapeutic agent against CDI, the bactericidal activity of 23 putative endolysins was compared and ΦCD27 endolysin CD27L was selected and modified to CD27L_EAD by cleaving the cell-wall binding domain of CD27L.
RESULTS
CD27L_EAD exhibited greater bacteriolytic activity than CD27L and its activity was stable over a wide range of salt concentrations and pH conditions. CD27L_EAD was added to a co-culture of human gut microbiota with C. difficile and the bacterial community structure was analyzed. CD27L_EAD did not impair the richness and diversity of the bacterial population but remarkably attenuated the abundance of C. difficile. Furthermore, the co-administration of vancomycin exerted synergistic bactericidal activity against C. difficile. β-diversity analysis revealed that CD27L_EAD did not significantly disturb the composition of the microbial community, whereas the abundance of some species belonging to the family Lachnospiraceae decreased after CD27L_EAD treatment.
CONCLUSIONS
This study provides insights into endolysin as a prospective therapeutic agent for the treatment of CDI without damaging the normal gut microbiota.
PubMed: 38810936
DOI: 10.1016/j.ijantimicag.2024.107222 -
Drug Development Research Jun 2024The World Health Organization (WHO) has published a list of priority pathogens that urgently require research to develop new antibiotics. The main aim of the current...
The World Health Organization (WHO) has published a list of priority pathogens that urgently require research to develop new antibiotics. The main aim of the current study is to identify potential marketed drugs that can be repurposed against bacterial infections. A pharmacovigilance-based drug repurposing approach was used to identify potential drugs. OpenVigil 2.1 tool was used to query the FDA Adverse Event Reporting System database. The reporting odds ratio (ROR) < 1, ROR95CI upper bound <1, and no. of cases ≥30 were used for filtering and sorting of drugs. Sunburst plot was used to represent drugs in a hierarchical order using the Anatomical Therapeutic Chemical classification. Molecular docking and dynamics were performed using the Maestro and Desmond modules of Schrodinger 2023 software respectively. A total of 40 drugs with different classes were identified based on the pharmacovigilance approach which has antibacterial potential. The molecular docking results have shown energetically favored binding conformation of lisinopril against 3-deoxy-manno-octulosonate cytidylyltransferase, UDP-2,3-diacylglucosamine hydrolase, and penicillin-binding protein 3 (PBP3) of Pseudomonas aeruginosa; olmesartan, atorvastatin against lipoteichoic acids flippase LtaA and rosiglitazone and varenicline against d-alanine ligase of Staphylococcus aureus; valsartan against peptidoglycan deacetylase (SpPgdA) and atorvastatin against CDP-activated ribitol for teichoic acid precursors of Streptococcus pneumoniae. Further, molecular dynamic results have shown the stability of identified drugs in the active site of bacterial targets except lisinopril with PBP3. Lisinopril, olmesartan, atorvastatin, rosiglitazone, varenicline, and valsartan have been identified as potential drugs for repurposing against bacterial infection.
Topics: Data Mining; Drug Repositioning; Humans; Molecular Docking Simulation; Pharmacovigilance; Anti-Bacterial Agents; Bacterial Infections; Adverse Drug Reaction Reporting Systems
PubMed: 38807372
DOI: 10.1002/ddr.22211 -
Scientific Reports May 2024Recently, Lactobacillus johnsonii N6.2-derived extracellular vesicles (EVs) were shown to reduce apoptosis in human beta cell lines and stimulate insulin secretion in...
Recently, Lactobacillus johnsonii N6.2-derived extracellular vesicles (EVs) were shown to reduce apoptosis in human beta cell lines and stimulate insulin secretion in human islets. Our goal was to identify a physiologically relevant environmental condition that induces a hypervesiculation phenotype in L. johnsonii N6.2 and to evaluate if transcriptional changes are involved in this process. Culturing this strain in the presence of 0.2% bovine bile, which mimics a stressor encountered by the bacterium in the small intestine, resulted in approximately a 100-fold increase in EVs relative to cells grown in media without bile. Whole transcriptome analysis of cells grown with bile revealed upregulation of several peptidoglycan hydrolases as well as several genes involved in fatty acid utilization. These results suggest that the hypervesiculation phenotype may be the result of increased cell wall turnover combined with increased accumulation of phospholipids, in agreement with our previous proteomic and lipidomics results. Additionally, EVs isolated from L. johnsonii N6.2 grown in presence of bile maintained their immunomodulatory properties in host-derived βlox5 pancreatic and THP-1 macrophage cell lines. Our findings suggest that in L. johnsonii N6.2 vesiculogenesis is significantly impacted by the expression of cell wall modifying enzymes and proteins utilized for exogenous fatty acid uptake that are regulated at the transcriptional level. Furthermore, this data suggests that vesiculogenesis could be stimulated in vivo using small molecules thereby maximizing the beneficial interactions between bacteria and their hosts.
Topics: Extracellular Vesicles; Humans; Lactobacillus johnsonii; Bile; Animals; Cell Line; Cattle; THP-1 Cells; Cell Wall; Gene Expression Profiling
PubMed: 38806562
DOI: 10.1038/s41598-024-62843-0 -
Journal of Agricultural and Food... Jun 2024Tolerance to bile stress is a crucial property for lactic acid bacteria (LAB) to survive in the gastrointestinal tract and exert their beneficial effects. Whey powder...
Tolerance to bile stress is a crucial property for lactic acid bacteria (LAB) to survive in the gastrointestinal tract and exert their beneficial effects. Whey powder enriched with milk fat globule membrane proteins (M-WPI) as a functional component is protective for strains under stress conditions. The current study investigated the key mechanisms of action involved in () CGMCC 23701 survival in the presence of bile and the protective mechanism of M-WPI. According to proteomic analysis (proteomics), there could be several reasons for the greater protective effect of M-WPI. These include promoting the synthesis of fatty acids and peptidoglycans to repair the structure of the cell surface, regulating the metabolism of carbohydrates and amino acids to release energy and produce a range of precursors, enabling the expression of the repair system to repair damaged DNA, and promoting the expression of proteins associated with the multidrug efflux pump, which facilitates the exocytosis of intracellular bile salts. This study helps us to better understand the changes in proteome of CGMCC 23701 under bile salt stress and M-WPI protection, which will provide a new method for the protection and development of functional LAB.
Topics: Lactobacillus plantarum; Lipid Droplets; Proteomics; Glycolipids; Bile Acids and Salts; Bacterial Proteins; Glycoproteins; Membrane Proteins; Stress, Physiological; Animals; Membrane Glycoproteins
PubMed: 38805674
DOI: 10.1021/acs.jafc.4c01747 -
Journal of Bioscience and Bioengineering May 2024Shewanella vesiculosa HM13, a psychrotrophic gram-negative bacterium isolated from the intestinal contents of horse mackerel, produces abundant extracellular membrane...
Enhancing extracellular membrane vesicle productivity of Shewanella vesiculosa HM13, a prospective host for vesiculation-mediated protein secretion, by weakening outer membrane-peptidoglycan linkage.
Shewanella vesiculosa HM13, a psychrotrophic gram-negative bacterium isolated from the intestinal contents of horse mackerel, produces abundant extracellular membrane vesicles (EMVs) by budding the outer membrane. The EMVs of this bacterium carry a single major cargo protein, P49, of unknown function, which may be useful as a carrier for the secretory production of heterologous proteins as cargoes of EMVs. In this study, to increase the utility of S. vesiculosa HM13 as a host for EMV-mediated protein production, we improved its EMV productivity by weakening the linkage between the outer membrane and underlying peptidoglycan layer. In gram-negative bacteria, the outer membrane is connected to peptidoglycans predominantly through Braun's lipoprotein (Lpp), and the formation of this linkage is catalyzed by an l,d-transpeptidase (Ldt). We constructed gene-disrupted mutants of Lpp and Ldt and assessed their EMV productivity. The EMVs of the lpp- and ldt-disrupted mutants grown at 18 °C were evaluated using nanoparticle tracking analysis, and their morphologies were observed using transmission electron microscopy. As a result, an approximately 2.5-fold increase in EMV production was achieved, whereas the morphology of the EMVs of these mutants remained almost identical to that of the parent strain. In accordance with the increase in EMV production, the mutants secreted approximately 2-fold higher amounts of P49 than the parent strain into the culture broth as the EMV cargo. These findings will contribute to the development of an EMV-based secretory production system for heterologous proteins using S. vesiculosa HM13 as a host.
PubMed: 38796341
DOI: 10.1016/j.jbiosc.2024.05.005 -
International Journal of Antimicrobial... May 2024The emergence of multidrug-resistant pathogens has outpaced the development of new antibiotics, leading to renewed interest in endolysins. Endolysins have been...
The emergence of multidrug-resistant pathogens has outpaced the development of new antibiotics, leading to renewed interest in endolysins. Endolysins have been investigated as novel biocontrol agents for Gram-positive bacteria. However, their efficacy against Gram-negative species is limited by the barrier presented by their outer membrane, which prevents endolysin access to the peptidoglycan substrate. Here, we used the translocation domain of botulinum neurotoxin to deliver endolysin across the outer membrane of Gram-negative bacteria. The translocation domain selectively interacts with and penetrates membranes composed of anionic lipids, which have been used in nature to deliver various proteins into animal cells. In addition to the botulinum neurotoxin translocation domain, we have fused bacteriophage-derived receptor binding protein to endolysins. This allows the attached protein to efficiently bind to a broad spectrum of Gram-negative bacteria. By attaching these target-binding and translocation machineries to endolysins, we aimed to develop an engineered endolysin with broad-spectrum targeting and enhanced antibacterial activity against Gram-negative species. To validate our strategy, we designed engineered endolysins using two well-known endolysins, T5 and LysPA26, and tested them against 23 strains from six species of Gram-negative bacteria, confirming that our machinery can act broadly. In particular, we observed a 2.32 log reduction in 30 min with only 0.5 µM against an Acinetobacter baumannii isolate. We also used the SpyTag/SpyCatcher system to easily attach target-binding proteins, thereby improving its target-binding ability. Overall, our newly developed endolysin engineering strategy may be a promising approach to control multidrug-resistant Gram-negative bacterial strains.
PubMed: 38795926
DOI: 10.1016/j.ijantimicag.2024.107216 -
Journal of Cosmetic Dermatology May 2024Acne vulgaris, a common chronic dermatological condition worldwide, is associated with inflammatory response and Cutibacterium acnes. Individuals with acne vulgaris and...
BACKGROUND
Acne vulgaris, a common chronic dermatological condition worldwide, is associated with inflammatory response and Cutibacterium acnes. Individuals with acne vulgaris and sensitive skin have limited suitable treatments due to the skin irritation and side effects exhibited by current hydroxy acidic medications.
AIMS
This study aimed to evaluate the synergistic effects of Guaiacum officinale (GO) and Rhodomyrtus Tomentosa (RT) extracts for treating acne vulgaris on sensitive skin by inhibiting inflammation.
METHODS
The phytochemical constituents and antioxidant activity of GO and RT extracts were determined in vitro. The anti-inflammatory effects were investigated in peptidoglycan (PGN)-induced HaCaT cells. Further, a 28-day clinical trial was conducted involving 30 subjects with both sensitive skin and acne to evaluate the efficacy and subjects' satisfaction.
RESULTS
Total phenolics and flavonoids were detected in GO and RT extracts, the IC values for DPPH radical scavenging were 6.15 wt% and 0.76 wt%, respectively. The combination of GO and RT extracts at a 1:1 (v/v) ratio significantly decreased the expression of TLR-2 and TLR-4, as well as the secretion of IL-1α, IL-8, and TNF-α in PGN-induced HaCaT cells, by 2.30-7.93 times compared to GO extract alone (p < 0.05). Moreover, the cream containing 5 wt% the combination significantly improved facial acne and redness (p < 0.05). The number of comedones decreased by 50.00% and papules by 30.65% after 28 days of application. No adverse events were reported and 96.67% of the subjects were satisfied with the treatment.
CONCLUSION
The efficacy of the GO and RT extracts in synergistically suppressing inflammation, improving acne vulgaris, and reducing redness. The study offers an effective and non-irritant treatment for acne vulgaris in individuals with sensitive skin.
PubMed: 38790116
DOI: 10.1111/jocd.16394