-
Microbiology Spectrum Jun 2022Carbapenem-resistant Enterobacteriaceae (CRE) are an urgent threat to public health requiring the development of novel therapies. TP0586532 is a novel non-hydroxamate...
Carbapenem-resistant Enterobacteriaceae (CRE) are an urgent threat to public health requiring the development of novel therapies. TP0586532 is a novel non-hydroxamate LpxC inhibitor that inhibits the synthesis of lipopolysaccharides, which are components of the outer membranes of Gram-negative bacteria. Based on the mechanism of action of TP0586532, we hypothesized that it might enhance the antibacterial activity of other antibiotics by increasing the permeability of the outer bacterial membrane. The combination of TP0586532 with meropenem, amikacin, cefepime, piperacillin, and tigecycline showed synergistic and additive effects against carbapenem-susceptible Klebsiella pneumoniae and Escherichia coli. Checkerboard experiments against 21 carbapenem-resistant K. pneumoniae and E. coli strains (13 +, 5 +, 2 +, and 1 +) showed that the combination of TP0586532 with meropenem yielded synergistic and additive effects against 9 and 12 strains, respectively. In a time-kill assay examining 12 CRE strains, synergistic effects were observed when TP0586532 was combined with meropenem against many of the strains. A membrane permeability assay using ethidium bromide (EtBr) was performed to investigate the mechanism of the potentiating effect. TP0586532 increased the influx of EtBr into a CRE strain, suggesting that TP0586532 increased membrane permeability and facilitated intracellular access for the antibiotics. Our study demonstrates that TP0586532 potentiates the antibacterial activity of meropenem against CRE. Combination therapy consisting of TP0586532 and meropenem has potential as a treatment for CRE infections. Carbapenem-resistant Enterobacteriaceae (CRE) are an urgent public health threat, as therapeutic options are limited. TP0586532 is a novel LpxC inhibitor that inhibits the synthesis of lipopolysaccharides in the outer membranes of Gram-negative bacteria. Here, we demonstrated the potentiating effects of TP0586532 on the antibacterial activity of meropenem against CRE harboring various types of carbapenemase genes (+, + +, and +). TP0586532 also augmented the bactericidal effects of meropenem against CRE strains, even against those with a high level of resistance to meropenem. The potentiating effects were suggested to be mediated by an increase in bacterial membrane permeability. Our study revealed that a combination therapy consisting of TP0586532 and meropenem has the potential to be a novel therapeutic option for CRE infections.
Topics: Humans; Anti-Bacterial Agents; Bacterial Proteins; beta-Lactamases; Butanols; Carbapenem-Resistant Enterobacteriaceae; Carbapenems; Enterobacteriaceae Infections; Escherichia coli; Gram-Negative Bacteria; Imidazoles; Klebsiella pneumoniae; Meropenem; Microbial Sensitivity Tests
PubMed: 35647694
DOI: 10.1128/spectrum.00828-22 -
Neuropharmacology Jul 2023Parvalbumin-expressing dorsal striatal fast-spiking interneurons, comprising ∼1% of the total dorsal striatal neuronal population, are necessary for the expression of...
Parvalbumin-expressing dorsal striatal fast-spiking interneurons, comprising ∼1% of the total dorsal striatal neuronal population, are necessary for the expression of compulsive-like ethanol consumption mice. Fast-spiking interneurons are driven to fire by glutamatergic inputs derived primarily from the cortex. However, these neurons also receive substantial GABAergic input from two sources: the globus pallidus and the reticular nucleus of the thalamus. How ethanol modulates inhibitory input onto fast-spiking neurons is unclear and, more broadly, alcohol effects on GABAergic synaptic transmission onto GABAergic interneurons are understudied. Examining this, we found that acute bath application of ethanol (50 mM) potentiated GABAergic transmission from both the globus pallidus and the reticular nucleus of the thalamus onto fast-spiking interneurons in mouse of both sexes. This ethanol-induced potentiation required postsynaptic calcium and was not accompanied by a sustained change in presynaptic GABA release probability. Examining whether this ethanol effect persisted following chronic intermittent ethanol exposure, we found attenuated acute-ethanol potentiation of GABAergic transmission from both the globus pallidus and the reticular nucleus of the thalamus onto striatal fast-spiking interneurons. These data underscore the impact of ethanol on GABAergic signaling in the dorsal striatum and support the notion that ethanol may disinhibit the dorsolateral striatum.
Topics: Animals; Female; Male; Mice; Corpus Striatum; Ethanol; GABAergic Neurons; Globus Pallidus; Interneurons; Synaptic Transmission; Thalamic Nuclei; Synapses; Calcium
PubMed: 37011784
DOI: 10.1016/j.neuropharm.2023.109527 -
Annals of Clinical Microbiology and... Dec 2021The chemotherapeutic management of infections has become challenging due to the global emergence of antibiotic resistant pathogenic bacteria. The recent expansion of... (Review)
Review
BACKGROUND AND OBJECTIVES
The chemotherapeutic management of infections has become challenging due to the global emergence of antibiotic resistant pathogenic bacteria. The recent expansion of studies on plant-derived natural products has lead to the discovery of a plethora of phytochemicals with the potential to combat bacterial drug resistance via various mechanisms of action. This review paper summarizes the primary antibiotic resistance mechanisms of bacteria and also discusses the antibiotic-potentiating ability of phytoextracts and various classes of isolated phytochemicals in reversing antibiotic resistance in anthrax agent Bacillus anthracis and emerging superbug bacteria.
METHODS
Growth inhibitory indices and fractional inhibitory concentration index were applied to evaluate the in vitro synergistic activity of phytoextract-antibiotic combinations in general.
FINDINGS
A number of studies have indicated that plant-derived natural compounds are capable of significantly reducing the minimum inhibitory concentration of standard antibiotics by altering drug-resistance mechanisms of B. anthracis and other superbug infection causing bacteria. Phytochemical compounds allicin, oleanolic acid, epigallocatechin gallate and curcumin and Jatropha curcas extracts were exceptional synergistic potentiators of various standard antibiotics.
CONCLUSION
Considering these facts, phytochemicals represents a valuable and novel source of bioactive compounds with potent antibiotic synergism to modulate bacterial drug-resistance.
Topics: Anthrax; Anti-Bacterial Agents; Bacillus anthracis; Biological Factors; Drug Resistance, Microbial; Drug Synergism; Humans; Microbial Sensitivity Tests; Phytochemicals; Plant Extracts
PubMed: 34856999
DOI: 10.1186/s12941-021-00485-0 -
Frontiers in Microbiology 2021Antibiotic resistance is a global health threat, and there is ample motivation for development of novel antibacterial approaches combining multiple strategies....
Antibiotic resistance is a global health threat, and there is ample motivation for development of novel antibacterial approaches combining multiple strategies. Electroporation is among the promising complementary techniques - highly optimizable, effective against a broad range of bacteria, and largely impervious to development of resistance. To date, most studies investigating electroporation as an efficacy potentiator for antibacterials used substances permissible in food industry, and only few used clinical antibiotics, as acceptable applications are largely limited to treatment of wastewaters inherently contaminated with such antibiotics. Moreover, most studies have focused mainly on maximal achievable effect, and less on underlying mechanisms. Here, we compare inactivation potentiation rates for three antibiotics with different modes of action: ampicillin (inhibits cell wall synthesis), ciprofloxacin (inhibits DNA replication), and tetracycline (inhibits protein synthesis). We used concentrations for each antibiotic from 0 to 30× its minimum inhibitory concentration, a single 1-ms electric pulse with amplitude from 0 to 20 kV/cm, and post-pulse pre-dilution incubation either absent (≲1 min) or lasting 60 min, 160 min, or 24 h. Our data show that with incubation, potentiation is significant for all three antibiotics, increases consistently with pulse amplitude, and generally also with antibiotic concentration and incubation time. With incubation, potentiation for ampicillin was rather consistently (although with weak statistical significance) superior to both ciprofloxacin and tetracycline: ampicillin was superior to both in 42 of 48 data points, including 7 with significance with respect to both, while at 60- and 160-min incubation, it was superior in 31 of 32 data points, including 6 with significance with respect to both. This suggests that electroporation potentiates wall-targeting antibiotics more than those with intracellular targets, providing motivation for in-depth studies of the relationship between the mode of action of an antibiotic and its potentiation by electroporation. Identification of substances permissible in foods and targeting the cell wall of both Gram-negative and Gram-positive bacteria might provide candidate antibacterials for broad and strong potentiation by electroporation applicable also for food preservation.
PubMed: 34733244
DOI: 10.3389/fmicb.2021.722232 -
Frontiers in Cellular Neuroscience 2022Recognizing familiar but innocuous stimuli and suppressing behavioral response to those stimuli are critical steps in dedicating cognitive resources to significant...
Recognizing familiar but innocuous stimuli and suppressing behavioral response to those stimuli are critical steps in dedicating cognitive resources to significant elements of the environment. Recent work in the visual system has uncovered key neocortical mechanisms of this familiarity that emerges over days. Specifically, exposure to phase-reversing gratings of a specific orientation causes long-lasting stimulus-selective response potentiation (SRP) in layer 4 of mouse primary visual cortex (V1) as the animal's behavioral responses are reduced through habituation. This plasticity and concomitant learning require the NMDA receptor and the activity of parvalbumin-expressing (PV+) inhibitory neurons. Changes over the course of seconds and minutes have been less well studied in this paradigm, so we have here characterized cortical plasticity occurring over seconds and minutes, as well as days, to identify separable forms of plasticity accompanying familiarity. In addition, we show evidence of interactions between plasticity over these different timescales and reveal key mechanistic differences. Layer 4 visual-evoked potentials (VEPs) are potentiated over days, and they are depressed over minutes, even though both forms of plasticity coincide with significant reductions in behavioral response. Adaptation, classically described as a progressive reduction in synaptic or neural activity, also occurs over the course of seconds, but appears mechanistically separable over a second as compared to tens of seconds. Interestingly, these short-term forms of adaptation are modulated by long-term familiarity, such that they occur for novel but not highly familiar stimuli. Genetic knock-down of NMDA receptors within V1 prevents all forms of plasticity while, importantly, the modulation of short-term adaptation by long-term familiarity is gated by PV+ interneurons. Our findings demonstrate that different timescales of adaptation/habituation have divergent but overlapping mechanisms, providing new insight into how the brain is modified by experience to encode familiarity.
PubMed: 35465612
DOI: 10.3389/fncel.2022.840057 -
International Journal of Molecular... Nov 2020Cationic antimicrobial peptides have attracted interest, both as antimicrobial agents and for their ability to increase cell permeability to potentiate other...
Synthesis and in Silico Modelling of the Potential Dual Mechanistic Activity of Small Cationic Peptides Potentiating the Antibiotic Novobiocin against Susceptible and Multi-Drug Resistant .
Cationic antimicrobial peptides have attracted interest, both as antimicrobial agents and for their ability to increase cell permeability to potentiate other antibiotics. However, toxicity to mammalian cells and complexity have hindered development for clinical use. We present the design and synthesis of very short cationic peptides (3-9 residues) with potential dual bacterial membrane permeation and efflux pump inhibition functionality. Peptides were designed based upon in silico similarity to known active peptides and efflux pump inhibitors. A number of these peptides potentiate the activity of the antibiotic novobiocin against susceptible and restore antibiotic activity against a multi-drug resistant strain, despite having minimal or no intrinsic antimicrobial activity. Molecular modelling studies, via docking studies and short molecular dynamics simulations, indicate two potential mechanisms of potentiating activity; increasing antibiotic cell permeation via complexation with novobiocin to enable self-promoted uptake, and binding the RND efflux pump. These peptides demonstrate potential for restoring the activity of hydrophobic drugs.
Topics: Antimicrobial Cationic Peptides; Chemistry Techniques, Synthetic; Drug Design; Drug Resistance, Multiple, Bacterial; Escherichia coli; Microbial Sensitivity Tests; Models, Molecular; Molecular Docking Simulation; Molecular Dynamics Simulation; Novobiocin; Structure-Activity Relationship
PubMed: 33266278
DOI: 10.3390/ijms21239134 -
Journal of Personalized Medicine Jan 2023The R334W (c.1000C>T, p.Arg334Trp) is a rare cystic fibrosis (CF)-causing mutation for which no causal therapy is currently approved. This mutation leads to a...
The R334W (c.1000C>T, p.Arg334Trp) is a rare cystic fibrosis (CF)-causing mutation for which no causal therapy is currently approved. This mutation leads to a significant reduction of CF transmembrane conductance regulator (CFTR) channel conductance that still allows for residual function. Potentiators are small molecules that interact with CFTR protein at the plasma membrane to enhance CFTR-dependent chloride secretion, representing thus pharmacotherapies targeting the root cause of the disease. Here, we generated a new CF bronchial epithelial (CFBE) cell line to screen a collection of compounds and identify novel potentiators for R334W-CFTR. The active compounds were then validated by electrophysiological assays and their additive effects in combination with VX-770, genistein, or VX-445 were exploited in this cell line and further confirmed in intestinal organoids. Four compounds (LSO-24, LSO-25, LSO-38, and LSO-77) were active in the functional primary screen and their ability to enhance R334W-CFTR-dependent chloride secretion was confirmed using electrophysiological measurements. In silico ADME analyses demonstrated that these compounds follow Lipinski’s rule of five and are thus suggested to be orally bioavailable. Dose−response relationships revealed nevertheless suboptimal efficacy and weak potency exerted by these compounds. VX-770 and genistein also displayed a small potentiation of R334W-CFTR function, while VX-445 demonstrated no potentiator activity for this mutation. In the R334W-expressing cell line, CFTR function was further enhanced by the combination of LSO-24, LSO-25, LSO-38, or LSO-77 with VX-770, but not with genistein. The efficacy of potentiator VX-770 combined with active LSO compounds was further confirmed in intestinal organoids (R334W/R334W genotype). Taken together, these molecules were demonstrated to potentiate R334W-CFTR function by a different mechanism than that of VX-770. They may provide a feasible starting point for the design of analogs with improved CFTR-potentiator activity.
PubMed: 36675763
DOI: 10.3390/jpm13010102 -
Pharmacognosy Research 2018Schistosomiasis is the most noteworthy parasitic disease after malaria. Furthermore, the significant activity of the genus against worms and its intermediate host...
UNLABELLED
Schistosomiasis is the most noteworthy parasitic disease after malaria. Furthermore, the significant activity of the genus against worms and its intermediate host snails reinforced the study of Andr. (SS) and L. (SM) for their molluscicidal and schistosomicidal potentiality. In this study, different extracts, fractions and isolated compounds of both species are evaluated for the molluscicidal and schistosomicidal potentialities. The niclosamide was used as positive molluscicide control against snails. Different extracts, fractions, or isolated compounds were used at a concentration of 100 μg/ml and dead snails were counted in each case. On the other hand, washed and sterilized adult worms were used in three replicates, and three worm pairs were placed in each well with 2 ml test solution of 100 μg/ml concentration. Positive (praziquantel [PZQ] 0.2 ug/ml) and negative controls were concurrently used and examined daily for 3 days for viability. The mortality rate was calculated and then both LC and LC were determined in triplicates. Highest potency was indicated to total glycoalkaloid (TGA) fraction of SM followed by TGA of SS. On the other hand, TGA fractions of both species showed higher potency than other extracts and isolated compounds. Meanwhile, solasodine-free aglycone showed declined activity compared to its glycosides. Promising molluscicidal and schistosomicidal activities were displayed which are attributed to the glycoalkaloid content. Therefore, this study can efficiently contribute toward validation of the traditional use of SS and SM in schistosomiasis control.
SUMMARY
The current study evaluated the molluscicidal and schistosomicidal activities of different extracts and fractions of two species. The glycoalkaloids content depicted a promising activity against both the snails and the adult worms. PZQ; Praziquantel, SM; , SS; , TGA; total glycoalkaloid.
PubMed: 29568198
DOI: 10.4103/pr.pr_71_17 -
In Vivo and In Silico Assessment of Diabetes Ameliorating Potentiality and Safety Profile of Leaves.Evidence-based Complementary and... 2022Diabetes mellitus is one of the most notable health dilemmas. Analyzing plants for new antidiabetic remedies has become an impressive territory for life science...
BACKGROUND
Diabetes mellitus is one of the most notable health dilemmas. Analyzing plants for new antidiabetic remedies has become an impressive territory for life science researchers. has long been used to treat diabetes. Thus, we strived to ascertain the hypoglycemic potentiality of extract of leaves of by in vivo and in silico approaches.
METHODS
Fresh leaves of were collected and shade-dried to prepare ethanolic extracts to evaluate pharmacological parameters. Diabetes was induced in rats via injecting alloxan through the intraperitoneal route at a dose of 150 mg/kg body weight. Humalyzer 3000 was used to perform a biochemical assay of collected samples from rats. Anti-hyperglycemic activity study along with overdose toxicity test was performed. The pharmacological activity of this plant was also evaluated through a molecular docking study. This in silico study investigated the binding affinity of natural ligands from against glycoside hydrolase enzymes.
RESULTS
We detected a peak plasma concentration of at 3 hours 45 minutes that is roughly similar to the peak plasma concentration of metformin. Again, in OGTT and anti-hyperglycemic tests, it has been ascertained that both plant extract and metformin can exert significant ( < 0.05) and highly significant ( < 0.01) hypoglycemic activity in a dose-dependent manner. Metformin exhibited better therapeutic efficacy than that of plant extract, but it possessed null statistical significance. Also, our safety profile expressed that, similar to metformin, the plant extract can restore the disturbed pathological state in a dose-oriented approach with a wide safety margin. In silico study also validated the potentialities of natural constituents of . This study suggested that G. can be considered as potential antidiabetic plant. Robust and meticulous investigation regarding plant chemistry and pharmacology in the future may bring about a new dimension that will aid in discovering antidiabetic drugs from this plant in the diabetes management system.
PubMed: 35096119
DOI: 10.1155/2022/9095504 -
Frontiers in Pharmacology 2023Despite its disadvantages, chemotherapy is still commonly used for the treatment of bladder cancer (BC). Developing natural supplements that can target cancer stem cells...
Despite its disadvantages, chemotherapy is still commonly used for the treatment of bladder cancer (BC). Developing natural supplements that can target cancer stem cells (CSCs) which cause drug resistance and distant metastasis is necessary. Chaga mushrooms are popular to have several health-promoting and anti-cancer potentials. Organoid culture can recapitulate tumor heterogeneity, epithelial environment, and genetic and molecular imprints of the original tissues. In the previous study, we generated dog bladder cancer organoids (DBCO) as a novel experimental model of muscle-invasive BCO. Therefore, the present study aimed to examine the anti-tumor potentials of Chaga mushroom extract (Chaga) against DBCO. Four strains of DBCO were used in the present study. Treatment with Chaga inhibited the cell viability of DBCO in a concentration-dependent way. Treatment of DBCO with Chaga has significantly arrested its cell cycle and induced apoptosis. Expression of bladder CSC markers, , , , and YAP1, declined in the Chaga-treated DBCO. Also, Chaga inhibited the phosphorylation of ERK in DBCO. Expression of downstream signals of ERK, and (, , , and ) was also inhibited by Chaga in DBCO. Interestingly, the combinational treatment of DBCO with Chaga and anti-cancer drugs, vinblastine, mitoxantrone, or carboplatin, showed a potentiating activity. , Chaga administration decreased tumor growth and weight of DBCO-derived xenograft in mice with the induction of necrotic lesions. In conclusion, Chaga diminished the cell viability of DBCO by inhibiting proliferation-related signals and stemness conditions as well as by arresting the cell cycle. Collectively, these data suggest the value of Chaga as a promising natural supplement that could potentiate the effect of adjuvant chemotherapy, lower its adverse effects, and thus, limit the recurrence and metastasis of BC.
PubMed: 37153767
DOI: 10.3389/fphar.2023.1159516