scholarly journals Expression of a Mycobacterium tuberculosis Arabinomannan Antigen In Vitro and In Vivo

2001 ◽  
Vol 69 (9) ◽  
pp. 5671-5678 ◽  
Author(s):  
J. Reid Schwebach ◽  
Arturo Casadevall ◽  
Rachel Schneerson ◽  
Zhongdong Dai ◽  
Xiaojuan Wang ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Culture Media ◽  
Extended Period ◽  
Tween 80 ◽  
Surface Expression ◽  
Dependent Manner ◽  
Bacteria Growth ◽  
Growth Changes

ABSTRACT The outermost layer of Mycobacterium tuberculosiscontains two major polysaccharides, arabinomannan (AM) and glucan (GC). We studied the in vitro and in vivo expression of anM. tuberculosis AM antigen using monoclonal antibody (MAb) 9d8 (2a), an isotype-switched variant of the immunoglobulin G3 (IgG3) MAb 9d8. MAb 9d8 had been previously shown to bind M. tuberculosis AM and the M. tuberculosis surface. Our in vitro experiments showed that MAb 9d8(2a) bound strongly to whole-cell M. tuberculosis Erdman but not to the CDC 1551 strain grown in medium for an extended period. However, AM antigen was detected in the culture supernatant of both strains, and its concentration increased in a time-dependent manner. The detection of AM antigen from both strains was decreased in the presence of Tween 80. In mice infected with M. tuberculosis Erdman, AM antigen accumulated in organ homogenates concomitant to an increase in bacterial organ burden and an increase in IgG and IgM titer to AM. These results (i) indicate that the surface expression of AM during in vitro growth changes with culture age, is strain dependent, and is affected by the presence of Tween 80 in the culture media; (ii) show that AM is produced by bacteria growth in vivo; and (iii) demonstrate that the amount of in vivo-detected AM can be dependent on the number of bacteria in the infected organ.

scholarly journals Podoplanin interaction with caveolin-1 promotes tumour cell migration and invasion

2018 ◽  
Author(s):  
Luisa Pedro ◽  
Jacqueline D. Shields
Keyword(s):  
Tumour Cell ◽  
Surface Expression ◽  
Alveolar Epithelial Cells ◽  
Migration And Invasion ◽  
Dependent Manner ◽  
Caveolin 1 ◽  
Alveolar Epithelial ◽  
Podoplanin Expression

AbstractPodoplanin, a highly O-glycosylated type-1 transmembrane glycoprotein, found in lymphatic endothelial cells, podocytes, alveolar epithelial cells and lymph node fibroblasts is also expressed by tumour cells, and is correlated with more aggressive disease. Despite numerous studies documenting podoplanin expression, the mechanisms underlying its tumour-promoting functions remain unclear. Using a murine melanoma cell line that endogenously expresses podoplanin, we demonstrate interactions with proteins necessary for cytoskeleton reorganization, adhesion and matrix degradation, and endocytosis/receptor recycling but also identify a novel interaction with caveolin-1. We generated a panel of podoplanin and caveolin-1 variants to determine the molecular interactions and functional consequences of these interactions. Complementary in vitro and in vivo systems confirmed the existence of a functional cooperation in which surface expression of both full length, signalling competent podoplanin and caveolin-1 are necessary to induce directional migration and invasion, which is executed via PAK1 and ERK1 pathways. Our findings establish that podoplanin signalling mediates the invasive properties of melanoma cells in a caveolin-1 dependent manner.Summary StatementThis manuscript describes a new interaction and functional cooperation between podoplanin and caveolin1 that drives tumour cell invasion into surrounding tissues.

scholarly journals Deletion of the Mycobacterium tuberculosis Resuscitation-Promoting Factor Rv1009 Gene Results in Delayed Reactivation from Chronic Tuberculosis

2006 ◽  
Vol 74 (5) ◽  
pp. 2985-2995 ◽  
Author(s):  
JoAnn M. Tufariello ◽  
Kaixia Mi ◽  
Jiayong Xu ◽  
Yukari C. Manabe ◽  
Anup K. Kesavan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mycobacterium Tuberculosis ◽  
Human Population ◽  
Acute Infection ◽  
Dependent Manner ◽  
Survival Times ◽  
Chronic Infections ◽  
Synthase Inhibitor

ABSTRACT Approximately one-third of the human population is latently infected with Mycobacterium tuberculosis, comprising a critical reservoir for disease reactivation. Despite the importance of latency in maintaining M. tuberculosis in the human population, little is known about the mycobacterial factors that regulate persistence and reactivation. Previous in vitro studies have implicated a family of five related M. tuberculosis proteins, called resuscitation promoting factors (Rpfs), in regulating mycobacterial growth. We studied the in vivo role of M. tuberculosis rpf genes in an established mouse model of M. tuberculosis persistence and reactivation. After an aerosol infection with the M. tuberculosis Erdman wild type (Erdman) or single-deletion rpf mutants to establish chronic infections in mice, reactivation was induced by administration of the nitric oxide (NO) synthase inhibitor aminoguanidine. Of the five rpf deletion mutants tested, one (ΔRv1009) exhibited a delayed reactivation phenotype, manifested by delayed postreactivation growth kinetics and prolonged median survival times among infected animals. Immunophenotypic analysis suggested differences in pulmonary B-cell responses between Erdman- and ΔRv1009-infected mice at advanced stages of reactivation. Analysis of rpf gene expression in the lungs of Erdman-infected mice revealed that relative expression of four of the five rpf-like genes was diminished at late times following reactivation, when bacterial numbers had increased substantially, suggesting that rpf gene expression may be regulated in a growth phase-dependent manner. To our knowledge, ΔRv1009 is the first M. tuberculosis mutant to have a specific defect in reactivation without accompanying growth defects in vitro or during acute infection in vivo.

scholarly journals Glucan Is a Component of the Mycobacterium tuberculosis Surface That Is Expressed In Vitro and In Vivo

2002 ◽  
Vol 70 (5) ◽  
pp. 2566-2575 ◽  
Author(s):  
J. Reid Schwebach ◽  
Aharona Glatman-Freedman ◽  
Leslie Gunther-Cummins ◽  
Zhongdong Dai ◽  
John B. Robbins ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Cell Envelope ◽  
Tween 80 ◽  
Enzyme Linked Immunosorbent Assay ◽  
In Vitro Growth ◽  
Comprehensive Picture ◽  
The Media ◽  
Surface Polysaccharide

ABSTRACT The outermost layer of Mycobacterium tuberculosis is composed primarily of two polysaccharides, glucan (GC) and arabinomannan. To analyze the surface polysaccharide composition of M. tuberculosis, we generated a monoclonal antibody (MAb) that binds M. tuberculosis GC and is known as MAb 24c5. Immunofluorescence and whole-mount immunoelectron microscopy indicated that GC is on the outermost portion of the bacteria. M. tuberculosis strains Erdman and CDC 1551 were analyzed for their ability to bind MAb 24c5 after in vitro growth in media with and without the detergent Tween 80. MAb 24c5 bound to Erdman and CDC 1551 at all culture times with only slightly greater apparent affinity after extended culture in the absence of Tween 80, indicating that a stable amount of GC polysaccharide antigen is associated with the cell surface of M. tuberculosis. An enzyme-linked immunosorbent assay indicated that GC is antigenically similar to glycogen, and the amount of GC antigen increased in the media of M. tuberculosis cultures grown either with or without the detergent Tween 80. Other nontuberculosis mycobacteria have antigenically similar GCs on their surfaces after in vitro growth. Inoculation of mice with live bacilli but not inoculation with dead bacilli elicited a strong antibody response to GC consistent with production of this antigen in vivo. Our results provide a more comprehensive picture of the M. tuberculosis cell envelope and the conditions that allow expression of M. tuberculosis GC.

Repurposing Glyburide as Antileishmanial Agent to Fight Against Leishmaniasis

2019 ◽  
Vol 26 (5) ◽  
pp. 371-376 ◽  
Author(s):  
Abdur Rub ◽  
Kamal Shaker ◽  
Mohammad Kashif ◽  
Mohd Arish ◽  
Abdul Aziz Bin Dukhyil ◽  
...  
Keyword(s):  
Leishmania Donovani ◽  
Culture Media ◽  
Drug Repurposing ◽  
Parasite Growth ◽  
High Rate ◽  
Mammalian Host ◽  
Dependent Manner ◽  
The World

Background: Leishmaniasis is caused by a protozoan parasite, Leishmania. It is common in more than 98 countries throughout the world. Due to insufficient availability of antileishmanial chemotherapeutics, it is an urgent need to search for new molecules which have better efficacy, low toxicity and are available at low cost. Objectives: There is a high rate of diabetic cases throughout the world that is why we planned to test the antileishmanial activity of glyburide, an effective sugar lowering drug used for the treatment of diabetes. In this study, glyburide showed a significant decrease in the parasite growth and survival in vitro in a dose-dependent manner. Methods: Anti-leishmanial activity of glyburide was checked by culturing Leishmania donovani promastigotes in the presence of glyburide in a dose and time dependent manner. Docking study against Leishmania donovani-Trypanothione synthetase (LdTrySyn) protein was performed using Autodock Vina tool. Results: Growth reversibility assay shows that growth of treated parasite was not reversed when transferred to fresh culture media after 7 days. Moreover, docking studies show efficient interactions of glyburide with key residues in the catalytic site of Leishmania donovani- Trypanothione synthetase (LdTrySyn), a very important leishmanial enzyme involved in parasite’s survival by detoxification of Nitric Oxide (NO) species, generated by the mammalian host as a defense molecule. Thus this study proves that the drug-repurposing is a beneficial strategy for identification of new and potent antileishmanial molecules. Conclusion: The results suggest that glyburide binds to LdTrySyn and inhibits its activity which further leads to the altered parasite morphology and inhibition of parasite growth. Glyburide may also be used in combination with other anti-leishmanial drugs to potentiate the response of the chemotherapy. Overall this study provides information about combination therapy as well as a single drug treatment for the infected patients suffering from diabetes. This study also provides raw information for further in vivo disease model studies to confirm the hypothesis.

scholarly journals Preclinical Testing of the Nitroimidazopyran PA-824 for Activity against Mycobacterium tuberculosis in a Series of In Vitro and In Vivo Models

2005 ◽  
Vol 49 (6) ◽  
pp. 2294-2301 ◽  
Author(s):  
Anne J. Lenaerts ◽  
Veronica Gruppo ◽  
Karen S. Marietta ◽  
Christine M. Johnson ◽  
Diane K. Driscoll ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Bacterial Load ◽  
Multidrug Resistant ◽  
Infection Model ◽  
Significant Activity ◽  
Dependent Manner ◽  
In Vivo Models ◽  
Long Term Treatment

ABSTRACT This study extends earlier reports regarding the in vitro and in vivo efficacies of the nitroimidazopyran PA-824 against Mycobacterium tuberculosis. PA-824 was tested in vitro against a broad panel of multidrug-resistant clinical isolates and was found to be highly active against all isolates (MIC < 1 μg/ml). The activity of PA-824 against M. tuberculosis was also assessed grown under conditions of oxygen depletion. PA-824 showed significant activity at 2, 10, and 50 μg/ml, similar to that of metronidazole, in a dose-dependent manner. In a short-course mouse infection model, the efficacy of PA-824 at 50, 100, and 300 mg/kg of body weight formulated in methylcellulose or cyclodextrin/lecithin after nine oral treatments was compared with those of isoniazid, rifampin, and moxifloxacin. PA-824 at 100 mg/kg in cyclodextrin/lecithin was as active as moxifloxacin at 100 mg/kg and isoniazid at 25 mg/kg and was slightly more active than rifampin at 20 mg/kg. Long-term treatment with PA-824 at 100 mg/kg in cyclodextrin/lecithin reduced the bacterial load below 500 CFU in the lungs and spleen. No significant differences in activity between PA-824 and the other single drug treatments tested (isoniazid at 25 mg/kg, rifampin at 10 mg/kg, gatifloxacin at 100 mg/kg, and moxifloxacin at 100 mg/kg) could be observed. In summary, its good activity in in vivo models, as well as its activity against multidrug-resistant M. tuberculosis and against M. tuberculosis isolates in a potentially latent state, makes PA-824 an attractive drug candidate for the therapy of tuberculosis. These data indicate that there is significant potential for effective oral delivery of PA-824 for the treatment of tuberculosis.

scholarly journals Determining the efficacy of hand sanitizers against virulent nosocomial infections

2020 ◽  
Author(s):  
Jawad Najdawi ◽  
Lester Hubble ◽  
Alec Scarborough ◽  
Matthew Watz ◽  
Paul Andrew Watson
Keyword(s):  
Ethyl Alcohol ◽  
Culture Media ◽  
Extended Period ◽  
Time Frame ◽  
P Values ◽  
Time Points ◽  
Hand Sanitizer ◽  
Hospital Acquired

The goal of this study was to determine the effectiveness of 0.13% benzalkonium chloride (BAC) (Steirolotion™), 100% ethanol, and 70% ethyl alcohol (Purell™) hand sanitizer in subduing the growth of nosocomial bacteria – methicillin resistant Staphylococcus  aureus  (MRSA), vancomycin resistant Enterococcus (VRE), and Pseudomonas  aeruginosa  (P.  aeruginosa ) - when plated on culture media over an extended period of time. In addition, our objective was to quantify the length of time these hand sanitizer agents remained effective, and to extrapolate their efficacy in decreasing the transmission of hospital-acquired infections. 50 microliters of either BAC, 100% ethanol, or 70% ethyl alcohol hand gel sanitizer were pipetted onto Trypticase soy agar with 5% sheep blood plates that were cultured with either MRSA, VRE, or P.  aeruginosa . The plates were then incubated at 37.0?. The zone of inhibition (ZOI) was measured daily for 5 days and additionally zones were noted whether or not regrowth recurred in areas where previous growth had initially been inhibited. BAC was found to be superior to both 100% ethanol and 70% ethyl alcohol in the inhibition of MRSA over all time points (p values < .05). BAC was found to be superior to 70% ethyl alcohol in the inhibition of VRE over all time points (p values < .05), but not statistically superior to 100% ethanol against the inhibition of VRE over any time points. BAC was found to be superior to 70% ethyl alcohol and 100% ethanol in the inhibition of pseudomonas over 72 and 24 hours, respectively (p values < .05). The results of this study demonstrate  in vitro  efficacy of BAC of preventing regrowth of common nosocomial bacteria over a prolonged period of time, especially when compared to ethyl alcohol. Further study is warranted to determine  in vivo  effectiveness of this formulation of BAC as well as the appropriate time frame of application for effectiveness against P.  aeruginosa .

scholarly journals Dual Mechanism of Action of 5-Nitro-1,10-Phenanthroline against Mycobacterium tuberculosis

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Saqib Kidwai ◽  
Chan-Yong Park ◽  
Shradha Mawatwal ◽  
Prabhakar Tiwari ◽  
Myung Geun Jung ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mechanism Of Action ◽  
Chemotherapeutic Agents ◽  
Intracellular Bacteria ◽  
Dependent Manner ◽  
Content Type ◽  
Structure Activity ◽  
Dual Mechanism

ABSTRACT New chemotherapeutic agents with novel mechanisms of action are urgently required to combat the challenge imposed by the emergence of drug-resistant mycobacteria. In this study, a phenotypic whole-cell screen identified 5-nitro-1,10-phenanthroline (5NP) as a lead compound. 5NP-resistant isolates harbored mutations that were mapped to fbiB and were also resistant to the bicyclic nitroimidazole PA-824. Mechanistic studies confirmed that 5NP is activated in an F420-dependent manner, resulting in the formation of 1,10-phenanthroline and 1,10-phenanthrolin-5-amine as major metabolites in bacteria. Interestingly, 5NP also killed naturally resistant intracellular bacteria by inducing autophagy in macrophages. Structure-activity relationship studies revealed the essentiality of the nitro group for in vitro activity, and an analog, 3-methyl-6-nitro-1,10-phenanthroline, that had improved in vitro activity and in vivo efficacy in mice compared with that of 5NP was designed. These findings demonstrate that, in addition to a direct mechanism of action against Mycobacterium tuberculosis, 5NP also modulates the host machinery to kill intracellular pathogens.

scholarly journals Deacylated lipopolysaccharide inhibits neutrophil adherence to endothelium induced by lipopolysaccharide in vitro.

1987 ◽  
Vol 165 (5) ◽  
pp. 1393-1402 ◽  
Author(s):  
T H Pohlman ◽  
R S Munford ◽  
J M Harlan
Keyword(s):  
Fatty Acids ◽  
Umbilical Vein ◽  
Surface Expression ◽  
Specific Cell ◽  
Dependent Manner ◽  
Toxic Activity ◽  
Neutrophil Adherence ◽  
Umbilical Vein Endothelial Cells

Selective deacylation of the nonhydroxylated fatty acids from S. typhimurium LPS by an acyloxyacyl hydrolase isolated from leukocytes reduces toxic activity of LPS in vivo. We examined the effect of deacylated LPS on neutrophil adherence to human umbilical vein endothelial cells (HUVE). Pretreatment of HUVE with LPS (13 ng/ml for 4 h) produced a marked increase in the adherence of subsequently added neutrophils. In contrast, there was no increase in the adherence of neutrophils to HUVE pretreated with deacylated LPS (up to 260 ng/ml for 4 h). Neutrophil adherence to HUVE pretreated with LPS decreased as the degree of LPS deacylation increased. Deacylated LPS was not only itself inactive, but it inhibited neutrophil-endothelial interactions induced by LPS. Neutrophil adherence to HUVE pretreated with LPS was inhibited by deacylated LPS in a dose-dependent manner. Complete inhibition of adherence was observed at a 20:1 ratio (wt/wt) of deacylated LPS to LPS. Significantly, inhibition of neutrophil adherence to HUVE pretreated with LPS was observed even when deacylated LPS was added to HUVE up to 60 min after LPS. Deacylated LPS, however, did not inhibit neutrophil adherence induced by pretreatment of HUVE with IL-1 or TNF-alpha. We conclude that enzymatic deacylation of the nonhydroxylated fatty acids of LPS abolishes the ability of LPS to induce surface expression of a neutrophil adherence promoting activity in HUVE. Furthermore, deacylated LPS inhibits neutrophil adherence to HUVE induced by LPS, perhaps by preventing the interaction of LPS with a specific cell-surface or intracellular target.

scholarly journals Nucleotide-Binding Oligomerization Domain Protein 2-Deficient Mice Control Infection with Mycobacterium tuberculosis

2007 ◽  
Vol 75 (11) ◽  
pp. 5127-5134 ◽  
Author(s):  
Sheetal Gandotra ◽  
Sihyug Jang ◽  
Peter J. Murray ◽  
Padmini Salgame ◽  
Sabine Ehrt
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Nucleotide Binding ◽  
Dependent Manner ◽  
Wild Type ◽  
Cytoplasmic Proteins ◽  
Antigen Presenting ◽  
Deficient Mice ◽  
Oligomerization Domain

ABSTRACT Nucleotide-binding oligomerization domain proteins (NODs) are modular cytoplasmic proteins implicated in the recognition of peptidoglycan-derived molecules. NOD2 has recently been shown to be important for host cell cytokine responses to Mycobacterium tuberculosis, to synergize with Toll-like receptor 2 (TLR2) in mediating these responses, and thus to serve as a nonredundant recognition receptor for M. tuberculosis. Here, we demonstrate that macrophages and dendritic cells from NOD2-deficient mice were impaired in the production of proinflammatory cytokines and nitric oxide following infection with live, virulent M. tuberculosis. Mycolylarabinogalactan peptidoglycan (PGN), the cell wall core of M. tuberculosis, stimulated macrophages to release tumor necrosis factor (TNF) and interleukin-12p40 in a partially NOD2-dependent manner, and M. tuberculosis PGN required NOD2 for the optimal induction of TNF. However, NOD2-deficient mice were no more susceptible to infection with virulent M. tuberculosis than wild-type mice: they controlled the replication of M. tuberculosis in lung, spleen, and liver as well as wild-type mice, and both genotypes displayed similar lung pathologies. In addition, mice doubly deficient for NOD2 and TLR2 were similarly able to control an M. tuberculosis infection. Thus, NOD2 appears to participate in the recognition of M. tuberculosis by antigen-presenting cells in vitro yet is dispensable for the control of the pathogen during in vivo infection.

scholarly journals Development of novel MOG analogues with increased stability to explore MCT2 and α-ketoglutarate biology in vivo

2021 ◽  
Author(s):  
Louise Fets ◽  
Patrícia M. Nunes ◽  
Sebastien Campos ◽  
Mariana Silva dos Santos ◽  
Natalie Bevan ◽  
...  
Keyword(s):  
Culture Media ◽  
Pharmacokinetic Profile ◽  
Monocarboxylate Transporter ◽  
Metabolic Effects ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cell Culture Media ◽  
Pharmacokinetic Properties

ABSTRACTα-ketoglutarate (αKG) is a central metabolic node with far-reaching influence on cellular physiology. The αKG analogue N-oxalylglycine (NOG) and its membrane-permeable pro-drug derivative dimethyloxalylglycine (DMOG) have been broadly used as tool compounds both in vitro and in vivo to study αKG-dependent processes. In cell culture media, DMOG is rapidly converted to MOG, a substrate of the monocarboxylate transporter MCT2. The expression level of MCT2 determines the intracellular concentration of NOG, and, as such, influences the molecular targets NOG engages with. Here we show that DMOG and MOG are highly unstable also in mouse blood. We therefore designed and characterised a series of MOG analogues with two aims: to improve pharmacokinetic properties, and to explore the pharmacophore of MCT2, a relatively understudied member of the SLC16 family. We report MOG analogues that maintain MCT2-dependent uptake, including NOG-generating compounds that replicate the metabolic effects of MOG in a concentration-dependent manner. One such analogue, IPOG, shows significantly increased blood stability, and an improved overall pharmacokinetic profile, leading to increased NOG accumulation in MCT2-expressing tumours versus isogenic controls.

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