scholarly journals Efficacy of BB-83698, a Novel Peptide Deformylase Inhibitor, in a Mouse Model of Pneumococcal Pneumonia

2004 ◽  
Vol 48 (1) ◽  
pp. 80-85 ◽  
Author(s):  
E. Azoulay-Dupuis ◽  
J. Mohler ◽  
J. P. Bédos
Keyword(s):  
Mouse Model ◽  
Lung Tissue ◽  
Resistant Strain ◽  
Peptide Deformylase ◽  
In Vitro Activity ◽  
Wild Type ◽  
Virulent Strains ◽  
Resistant Strains

ABSTRACT The efficacy of BB-83698, a novel potent peptide deformylase inhibitor, was evaluated in a mouse model of acute pneumonia. The Streptococcus pneumoniae isolates tested included four virulent strains (one penicillin-susceptible wild-type strain, one macrolide-resistant strain, and two quinolone-resistant mutants [a mutant carrying mutations in ParC and GyrA and an efflux mutant] isogenic to the wild type) and two poorly virulent penicillin-resistant strains. Pneumonia was induced by intratracheal inoculation of 105 CFU (virulent strains) into immunocompetent mice or 107 CFU (less virulent strains) into leukopenic mice. Animals received three or six subcutaneous injections of antibiotics at 12- or 24-h intervals, with antibiotic treatment initiated at 3, 6, 12, or 18 h postinfection (p.i.). BB-83698 showed potent in vitro activity against all strains (MICs, 0.06 to 0.25 μg/ml). In the in vivo model, all control animals died within 2 to 5 days of infection. BB-83698 (80 mg/kg of body weight twice daily or 160 mg/kg once daily) protected 70 to 100% of the animals, as measured 10 days p.i., regardless of the preexisting resistance mechanisms. In contrast, the survival rates for animals treated with the comparator antibiotics were 30% for animals treated with erythromycin (100 mg/kg) and infected with the macrolide-resistant strain, 34% for animals treated with amoxicillin (200 mg/kg every 8 h) and infected with the penicillin-resistant strain, and 0 and 78% for animals treated with ciprofloxacin (250 mg/kg) and infected with the ParC and GyrA mutant and the efflux mutant, respectively. At 80 mg/kg, BB-83698 generated a peak concentration in lung tissue of 61.9 μg/ml within 1 h and areas under the concentration-times curves of 57.4 and 229.4 μg · h/ml for plasma and lung tissue, respectively. The emergence of S. pneumoniae isolates with reduced susceptibilities to BB-83698 was not observed following treatment with a suboptimal dosing regimen. In conclusion, the potent in vitro activity of BB-83698 against S. pneumoniae, including resistant strains, translates into good in vivo efficacy in a mouse pneumonia model.

In vitro activity of APX2041, a new GWT1-inhibitor and in vivo efficacy of the prodrug APX2104 against Aspergillus fumigatus

2021 ◽  
Author(s):  
Shareef K. Shaheen ◽  
Praveen R. Juvvadi ◽  
John Allen IV ◽  
E. Keats Shwab ◽  
D. Christopher Cole ◽  
...  
Keyword(s):  
Invasive Aspergillosis ◽  
Aspergillus Fumigatus ◽  
Vitro Activity ◽  
Prolonged Survival ◽  
In Vitro Activity ◽  
Wild Type ◽  
In Vivo Efficacy ◽  
Resistant Strains

Invasive aspergillosis (IA) due to Aspergillus fumigatus is a deadly infection for which new antifungal therapies are needed. Here we demonstrate the efficacy of a Gwt1 inhibitor, APX2041, and its prodrug, APX2104, against A. fumigatus . The wild-type, azole-resistant and echinocandin-resistant A. fumigatus strains were equally susceptible to APX2041 in vitro . APX2104 treatment in vivo significantly prolonged survival of neutropenic mice challenged with the wild-type and azole-resistant strains, revealing APX2104 as a potentially promising therapeutic against IA.

scholarly journals Murine monoclonal antibodies against RBD of SARS-CoV-2 neutralize authentic wild type SARS-CoV-2 as well as B.1.1.7 and B.1.351 viruses and protect in vivo in a mouse model in a neutralization dependent manner

2021 ◽  
Author(s):  
Fatima Amanat ◽  
Shirin Strohmeier ◽  
Wen-Hsin Lee ◽  
Sandhya Bangaru ◽  
Andrew B Ward ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Severe Acute Respiratory Syndrome ◽  
Mouse Model ◽  
Neutralizing Antibodies ◽  
Dependent Manner ◽  
Receptor Binding Domain ◽  
Wild Type ◽  
Murine Monoclonal Antibodies

After first emerging in December 2019 in China, severe acute respiratory syndrome 2 (SARS-CoV-2) has since caused a pandemic leading to millions of infections and deaths worldwide. Vaccines have been developed and authorized but supply of these vaccines is currently limited. With new variants of the virus now emerging and spreading globally, it is essential to develop therapeutics that are broadly protective and bind conserved epitopes in the receptor binding domain (RBD) or the whole spike of SARS-CoV-2. In this study, we have generated mouse monoclonal antibodies (mAbs) against different epitopes on the RBD and assessed binding and neutralization against authentic SARS-CoV-2. We have demonstrated that antibodies with neutralizing activity, but not non-neutralizing antibodies, lower viral titers in the lungs when administered in a prophylactic setting in vivo in a mouse challenge model. In addition, most of the mAbs cross-neutralize the B.1.351 as well as the B.1.1.7 variants in vitro.

CHIR258, a Novel Multi-Targeted Tyrosine Kinase Inhibitor, for the Treatment of t(4;14) Multiple Myeloma.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 641-641 ◽  
Author(s):  
Suzanne Trudel ◽  
Zhi Hua Li ◽  
Ellen Wei ◽  
Marion Wiesmann ◽  
Katherine Rendahl ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Mouse Model ◽  
Tyrosine Kinase ◽  
Cell Lines ◽  
Small Molecule ◽  
Kinase Inhibitor ◽  
Wild Type ◽  
Myeloma Cells

Abstract The t(4;14) translocation that occurs uniquely in a subset (15%) of multiple myeloma (MM) patients results in the ectopic expression of the receptor tyrosine kinase, Fibroblast Growth Factor Receptor3 (FGFR3). Wild-type FGFR3 induces proliferative signals in myeloma cells and appears to be weakly transforming in a hematopoeitic mouse model. The subsequent acquisition of FGFR3 activating mutations in some MM is associated with disease progression and is strongly transforming in several experimental models. The clinical impact of t(4;14) translocations has been demonstrated in several retrospective studies each reporting a marked reduction in overall survival. We have previously shown that inhibition of activated FGFR3 causes morphologic differentiation followed by apoptosis of FGFR3 expressing MM cell lines, validating activated FGFR3 as a therapeutic target in t(4;14) MM and encouraging the clinical development of FGFR3 inhibitors for the treatment of these poor-prognosis patients. CHIR258 is a small molecule kinase inhibitor that targets Class III–V RTKs and inhibits FGFR3 with an IC50 of 5 nM in an in vitro kinase assay. Potent anti-tumor and anti-angiogenic activity has been demonstrated in vitro and in vivo. We employed the IL-6 dependent cell line, B9 that has been engineered to express wild-type FGFR3 or active mutants of FGFR3 (Y373C, K650E, G384D and 807C), to screen CHIR258 for activity against FGFR3. CHIR258 differentially inhibited FGF-mediated growth of B9 expressing wild-type and mutant receptors found in MM, with an IC50 of 25 nM and 80 nM respectively as determined by MTT proliferation assay. Growth of these cells could be rescued by IL-6 demonstrating selectivity of CHIR258 for FGFR3. We then confirmed the activity of CHIR258 against FGFR3 expressing myeloma cells. CHIR258 inhibited the viability of FGFR3 expressing KMS11 (Y373C), KMS18 (G384D) and OPM-2 (K650E) cell lines with an IC50 of 100 nM, 250 nM and 80 nM, respectively. Importantly, inhibition with CHIR258 was still observed in the presence of IL-6, a potent growth factors for MM cells. U266 cells, which lack FGFR3 expression, displayed minimal growth inhibition demonstrating that at effective concentrations, CHIR258 exhibits minimal nonspecific cytotoxicity on MM cells. Further characterization of this finding demonstrated that inhibition of cell growth corresponded to G0/G1 cell cycle arrest and dose-dependent inhibition of downstream ERK phosphorylation. In responsive cell lines, CHIR258 induced apoptosis via caspase 3. In vitro combination analysis of CHIR258 and dexamethasone applied simultaneously to KMS11 cells indicated a synergistic interaction. In vivo studies demonstrated that CHIR258 induced tumor regression and inhibited growth of FGFR3 tumors in a plasmacytoma xenograft mouse model. Finally, CHIR258 produced cytotoxic responses in 4/5 primary myeloma samples derived from patients harboring a t(4;14) translocation. These data indicate that the small molecule inhibitor, CHIR258 potently inhibits FGFR3 and has activity against human MM cells setting the stage for a Phase I clinical trial of this compound in t(4;14) myeloma.

scholarly journals Mutation of the Maturase Lipoprotein Attenuates the Virulence of Streptococcus equi to a Greater Extent than Does Loss of General Lipoprotein Lipidation

2006 ◽  
Vol 74 (12) ◽  
pp. 6907-6919 ◽  
Author(s):  
Andrea Hamilton ◽  
Carl Robinson ◽  
Iain C. Sutcliffe ◽  
Josh Slater ◽  
Duncan J. Maskell ◽  
...  
Keyword(s):  
Mouse Model ◽  
Mutant Strain ◽  
Natural Host ◽  
Wild Type ◽  
Animal Suffering ◽  
Organ Cultures ◽  
Mucus Production ◽  
Streptococcus Equi

ABSTRACT Streptococcus equi is the causative agent of strangles, a prevalent and highly contagious disease of horses. Despite the animal suffering and economic burden associated with strangles, little is known about the molecular basis of S. equi virulence. Here we have investigated the contributions of a specific lipoprotein and the general lipoprotein processing pathway to the abilities of S. equi to colonize equine epithelial tissues in vitro and to cause disease in both a mouse model and the natural host in vivo. Colonization of air interface organ cultures after they were inoculated with a mutant strain deficient in the maturase lipoprotein (ΔprtM 138 - 213, with a deletion of nucleotides 138 to 213) was significantly less than that for cultures infected with wild-type S. equi strain 4047 or a mutant strain that was unable to lipidate preprolipoproteins (Δlgt 190 - 685). Moreover, mucus production was significantly greater in both wild-type-infected and Δlgt 190 - 685-infected organ cultures. Both mutants were significantly attenuated compared with the wild-type strain in a mouse model of strangles, although 2 of 30 mice infected with the Δlgt 190 - 685 mutant did still exhibit signs of disease. In contrast, only the ΔprtM 138 - 213 mutant was significantly attenuated in a pony infection study, with 0 of 5 infected ponies exhibiting pathological signs of strangles compared with 4 of 4 infected with the wild-type and 3 of 5 infected with the Δlgt 190 - 685 mutant. We believe that this is the first study to evaluate the contribution of lipoproteins to the virulence of a gram-positive pathogen in its natural host. These data suggest that the PrtM lipoprotein is a potential vaccine candidate, and further investigation of its activity and its substrate(s) are warranted.

scholarly journals 1208. Omadacycline In Vitro Activity Against Bacillus Anthracis

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S694-S695
Author(s):  
Alisa W Serio ◽  
H Carl Gelhaus ◽  
Noah Eichelberger ◽  
Henry S Heine ◽  
Diane M Anastasiou ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Resistant Strain ◽  
Clinical Laboratory ◽  
Independent Study ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Study Sites ◽  
Mic Value

Abstract Background Bacillus anthracis, the etiological agent of anthrax, is one of the agents most likely to be used in a biologic attack. Omadacycline previously has demonstrated potent in vitro and in vivo activity against B. anthracis. This project evaluated the in vitro activity of omadacycline against a larger set of B. anthracis strains across two laboratories. Methods Methods: Antibiotic susceptibility testing followed Clinical Laboratory Standard Institute methods against a collection of 53 B. anthracis strains at the University of Florida (UF) and 50 B. anthracis strains at MRIGlobal, representing human and animal isolates from North America, Africa, Europe, Asia, and Australia. Minimum inhibitory concentrations (MICs) for omadacycline and comparators at both sites (doxycycline, ciprofloxacin, levofloxacin, moxifloxacin) were determined by broth microdilution. Results Results: In the UF study, omadacycline demonstrated an MIC50 of 0.015 mg/L and an MIC90 of 0.03 mg/L against B. anthracis. Omadacycline MIC values were equal to or lower than doxycycline. In the MRIGlobal study, omadacycline demonstrated an MIC50 of 0.06 mg/L and an MIC90 of 0.06 mg/L (Table 1). All comparator MIC values were within ranges previously observed against these strains. Against a ciprofloxacin-resistant strain (MIC = 2 mg/L), omadacycline had an MIC value of 0.015 mg/L; against a doxycycline-resistant strain (MIC = 4 mg/L), omadacycline had an MIC value of 0.06 mg/L. Reproducibility was observed between the 2 laboratories for omadacycline in vitro activity against B. anthracis (Table 2). Table 1. MIC Concentration Summary for Omadacycline and Comparators Against B. anthracis Strains Table 2. Reproducibility of Omadacycline in Vitro Activity Against B. anthracis Strains Conclusion Based on the in vitro activity in both studies, omadacycline has the potential to be effective in treating anthrax infection. Reproducibility of omadacycline in vitro activity against B. anthracis was observed at 2 independent study sites. Disclosures Alisa W. Serio, PhD, Paratek Pharmaceuticals, Inc. (Employee, Shareholder) Diane M. Anastasiou, BA, Paratek Pharmaceuticals, Inc. (Consultant)

In Vitro and In Vivo Characterization of a Murine Model of Suppressed Intrinsic Pathway Using a FX Variant: FXRoma.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2697-2697
Author(s):  
Elise Roy ◽  
Paris Margaritis ◽  
Harre D. Downey ◽  
Katherine A. High
Keyword(s):  
Mouse Model ◽  
Thrombus Formation ◽  
Bleeding Tendency ◽  
Factor X ◽  
Wild Type ◽  
Intrinsic Pathway ◽  
Vessel Occlusion ◽  
Tail Clip

Abstract The complex and dynamic interplay between the intrinsic and extrinsic pathways of blood coagulation is incompletely understood. The mediator of prothrombin cleavage, Factor X (FX), plays a pivotal role as part of both the extrinsic and intrinsic tenase complexes. Moreover, the existence of naturally occurring Factor X mutations that can be asymmetrically activated through one but not both of these pathways affords one strategy for analyzing the relationship of the two pathways. The Factor X Roma (FXRoma) variant, originally described in a patient with mild bleeding tendency (severe following trauma, De Stefano et al., 1988), is due to a missense mutation (Thr318←Met) in exon 8. Coagulation testing revealed markedly decreased activity (1–3% wild-type) in the intrinsic pathway as measured by aPTT, but substantially higher activity (30–50% wild-type) in the extrinsic pathway as measured by PT. We chose to generate a mouse model of FX asymmetric activation to further probe the extrinsic-intrinsic pathway physiological relationship in hemostasis and thrombosis. For this, we used both an in vitro and an in vivo approach. We first constructed and purified the mouse homolog of FXRoma (mFXRoma) as well as wild-type mFX. Using a clotting-based assay, mFXRoma exhibited intrinsic and extrinsic activity comparable to that reported for the human mutation (5% and 18%, respectively). The reduced intrinsic and extrinsic activity of mFXRoma was not due to a secretion defect, based on Western blot analysis of supernatant and cell extracts from mFXRoma and mFX stably-transfected human embryonic kidney (HEK-293) cell lines. Mice homozygous for the analogous mutation (Thr315←Met) in exon 8 of the murine FX gene were generated by using a plug-and-socket approach. This resulted in the endogenous mFX exon 8 sequence being replaced with the mutated one, thus affording gene expression under the endogenous promoter. Analysis of mFXRoma homozygous mice showed a 6.4% and 19.2% intrinsic and extrinsic activity relative to wild-type littermates, respectively, confirming our in vitro data. The reduced activity in these mice resulted in a slight reduction in levels of the thrombin-antithrombin (TAT) complex. To determine any physiological defect of this mutation on the two pathways of coagulation, we performed two hemostatic challenges of the macrocirculation (tail clip and FeCl3-induced thrombus formation). In the tail-clip assay, blood loss showed no statistical difference between wild-type (n=5) and mFXRoma (n=6) mice. In contrast, following FeCl3-induced injury on the carotid artery (larger vessel diameter that in the tail), mFXRoma mice (3/3) failed to result in vessel occlusion (up to 30 min of observation), whereas wild-type littermates showed stable vessel occlusion (3/4) within ∼6 min of FeCl3 application. Although the type of injury was different, these data suggest that an impeded intrinsic activity of FX does not appear to affect hemostasis of the macrocirculation at relatively small diameter vessels but is essential for thrombus formation in large diameter vessels, and a relatively normal extrinsic activity does not compensate for this defect. This mouse model will aid in determining the safety and efficacy of therapeutic approaches based on impeding the intrinsic pathway of coagulation.

scholarly journals Efficacy of Cethromycin, a New Ketolide, against Streptococcus pneumoniae Susceptible or Resistant to Erythromycin in a Murine Pneumonia Model

2006 ◽  
Vol 50 (9) ◽  
pp. 3033-3038 ◽  
Author(s):  
E. Azoulay-Dupuis ◽  
J. Mohler ◽  
J. P. Bédos ◽  
C. Barau ◽  
B. Fantin
Keyword(s):  
Streptococcus Pneumoniae ◽  
Survival Rates ◽  
Administration Route ◽  
Serum Protein Binding ◽  
In Vitro Activity ◽  
Serotype 1 ◽  
Resistant Strains ◽  
Immunocompetent Mice

ABSTRACT Cethromycin is a ketolide with in vitro activity against macrolide-sensitive and -resistant strains of Streptococcus pneumoniae. We compared its in vivo efficacy to erythromycin in a mouse model of acute pneumonia induced by two virulent clinical strains: a serotype 3 susceptible strain (P-4241) (MICs: erythromycin, 0.03 μg/ml; cethromycin, 0.015 μg/ml) and a serotype 1 strain resistant to erythromycin (P-6254; phenotypically MLSB constitutive) (MICs: erythromycin, 1,024 μg/ml; cethromycin, 0.03 μg/ml). Immunocompetent mice were infected with 105 CFU of each strain. Six treatments given either subcutaneously (s.c.) or per os (p.o.) at 12-h intervals were initiated at 6 or 12 h after infection. Against P-4241, cethromycin given s.c. at 25 or 12.5 mg/kg protected 100% of the animals, with lungs and blood completely cleared of bacteria. Given p.o., cethromycin maintained its efficacy with 100 and 86% survival at 25 and 12.5 mg/kg, respectively. Erythromycin, given s.c. at 50 or 37.5 mg/kg, provided 50 and 38% survival rates, respectively. Against P-6254, cethromycin was effective at 25 mg/kg (100% survival) regardless of the administration route, whereas only 25 and 8% of animals survived after a 75-mg/kg erythromycin treatment given s.c. and p.o., respectively. The serum protein binding levels of cethromycin were 94.8 and 88.5% after doses of 12.5 and 25 mg/kg, respectively. The higher in vivo activity of cethromycin compared to erythromycin could be explained by favorable pharmacokinetic/pharmacodynamic indexes against P-6254 but not against P-4241.

scholarly journals CYP4F18-Deficient Neutrophils Exhibit Increased Chemotaxis to Complement Component C5a

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Rachel Vaivoda ◽  
Christine Vaine ◽  
Cassandra Boerstler ◽  
Kristy Galloway ◽  
Peter Christmas
Keyword(s):  
Weight Loss ◽  
Mouse Model ◽  
Immune Regulation ◽  
Complement Component ◽  
Wild Type ◽  
Eicosanoid Synthesis ◽  
Colonic Tissue ◽  
Significant Difference

CYP4Fs were first identified as enzymes that catalyze hydroxylation of leukotriene B4(LTB4). CYP4F18 has an unusual expression in neutrophils and was predicted to play a role in regulating LTB4-dependent inflammation. We compared chemotaxis of wild-type andCyp4f18knockout neutrophils using anin vitroassay. There was no significant difference in the chemotactic response to LTB4, but the response to complement component C5a increased 1.9–2.25-fold in knockout cells compared to wild-type (P< 0.01). This increase was still observed when neutrophils were treated with inhibitors of eicosanoid synthesis. There were no changes in expression of other CYP4 enzymes in knockout neutrophils that might compensate for loss of CYP4F18 or lead to differences in activity. A mouse model of dextran sodium sulfate colitis was used to investigate the consequences of increased C5a-dependent chemotaxisin vivo, but there was no significant difference in weight loss, disease activity, or colonic tissue myeloperoxidase between wild-type andCyp4f18knockout mice. This study demonstrates the limitations of inferring CYP4F function based on an ability to use LTB4as a substrate, points to expanding roles for CYP4F enzymes in immune regulation, and underscores thein vivochallenges of CYP knockout studies.

scholarly journals Loss of Sigma Factor RpoN Increases Intestinal Colonization of Vibrio parahaemolyticus in an Adult Mouse Model

2013 ◽  
Vol 82 (2) ◽  
pp. 544-556 ◽  
Author(s):  
W. Brian Whitaker ◽  
Gary P. Richards ◽  
E. Fidelma Boyd
Keyword(s):  
Mouse Model ◽  
Sigma Factor ◽  
Vibrio Parahaemolyticus ◽  
Wild Type ◽  
Carbon Utilization ◽  
Content Type ◽  
Wide Range ◽  
Competition Assays

ABSTRACTVibrio parahaemolyticusis the leading cause of bacterial seafood-borne gastroenteritis worldwide, yet little is known about how this pathogen colonizes the human intestine. The alternative sigma factor RpoN/sigma-54 is a global regulator that controls flagellar synthesis, as well as a wide range of nonflagellar genes. We constructed an in-frame deletion mutation inrpoN(VP2670) inV. parahaemolyticusRIMD2210633, a clinical serogroup O3:K6 isolate, and examined the effectsin vivousing a streptomycin-treated mouse model of colonization. We confirmed that deletion ofrpoNrenderedV. parahaemolyticusnonmotile, and it caused reduced biofilm formation and an apparent defect in glutamine synthetase production. Inin vivocompetition assays between therpoNmutant and a wild-type RIMD2210633 strain marked with the β-galactosidase genelacZ(WBWlacZ), the mutant colonized significantly more proficiently. Intestinal persistence competition assays also demonstrated that therpoNmutant had enhanced fitness and outcompeted WBWlacZ. Mutants defective in the polar flagellum biosynthesis FliAP sigma factor also outcompeted WBWlacZ but not to the same level as therpoNmutant, which suggested that lack of motility is not the sole cause of the fitness effect. In anin vitrogrowth competition assay in mouse intestinal mucus, therpoNmutant also outcompeted the wild type and exhibited faster doubling times when grown in mucus and on individual components of mucus. Genes in the pathways for the catabolism of mucus sugars also had significantly higher expression levels in a ΔrpoNmutant than in the wild type. These data suggest that inV. parahaemolyticus, RpoN plays an important role in carbon utilization regulation, which may significantly affect host colonization.

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