scholarly journals Diphenylpyrazole-Derived Compounds Increase Survival Time of Mice after Prion Infection

2011 ◽  
Vol 55 (10) ◽  
pp. 4774-4781 ◽  
Author(s):  
Fabienne Leidel ◽  
Martin Eiden ◽  
Markus Geissen ◽  
Hans A. Kretzschmar ◽  
Armin Giese ◽  
...  
Keyword(s):  
High Throughput Screening ◽  
Natural Infection ◽  
New Drugs ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Variant Form ◽  
Screening Assay ◽  
High Throughput Screening Assay

ABSTRACTTransmissible spongiform encephalopathies (TSEs) represent a group of fatal neurodegenerative disorders that can be transmitted by natural infection or inoculation. TSEs include scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle, and Creutzfeldt-Jakob disease (CJD) in humans. The emergence of a variant form of CJD (vCJD), which has been associated with BSE, produced strong pressure to search for effective treatments with new drugs. Up to now, however, TSEs have proved incurable, although many efforts have been made bothin vitroandin vivoto search for potent therapeutic and prophylactic compounds. For this purpose, we analyzed a compound library consisting of 10,000 compounds with a cell-based high-throughput screening assay dealing with scrapie-infected scrapie mouse brain and ScN2A cells and identified a new class of inhibitors consisting of 3,5-diphenylpyrazole (DPP) derivatives. The most effective DPP derivative showed half-maximal inhibition of PrPScformation at concentrations (IC50) of 0.6 and 1.2 μM, respectively. This compound was subsequently subjected to a number of animal experiments using scrapie-infected wild-type C57BL/6 and transgenic Tga20 mice. The DPP derivative induced a significant increase of incubation time both in therapeutic and prophylactic experiments. The onset of the prion disease was delayed by 37 days after intraperitoneal and 42 days after oral application, respectively. In summary, we demonstrate a highin vitroefficiency of DPP derivatives against prion infections that was substantiatedin vivofor one of these compounds. These results indicate that the novel class of DPP compounds should comprise excellent candidates for future therapeutic studies.

scholarly journals Small Molecule Receptor Binding Inhibitors with In Vivo Efficacy against Botulinum Neurotoxin Serotypes A and E

2021 ◽  
Vol 22 (16) ◽  
pp. 8577
Author(s):  
Alon Ben David ◽  
Ada Barnea ◽  
Eran Diamant ◽  
Eyal Dor ◽  
Arieh Schwartz ◽  
...  
Keyword(s):  
Receptor Binding ◽  
High Throughput Screening ◽  
Lethal Dose ◽  
Screening Assay ◽  
Vitro Assay ◽  
Time To Death ◽  
High Throughput Screening Assay ◽  
Binding Inhibitors

Botulinum neurotoxins (BoNTs) are the most poisonous substances in nature. Currently, the only therapy for botulism is antitoxin. This therapy suffers from several limitations and hence new therapeutic strategies are desired. One of the limitations in discovering BoNT inhibitors is the absence of an in vitro assay that correlates with toxin neutralization in vivo. In this work, a high-throughput screening assay for receptor-binding inhibitors against BoNT/A was developed. The assay is composed of two chimeric proteins: a receptor-simulating protein, consisting of the fourth luminal loop of synaptic vesicle protein 2C fused to glutathione-S-transferase, and a toxin-simulating protein, consisting of the receptor-binding domain of BoNT/A fused to beta-galactosidase. The assay was applied to screen the LOPAC1280 compound library. Seven selected compounds were evaluated in mice exposed to a lethal dose of BoNT/A. The compound aurintricarboxylic acid (ATA) conferred 92% protection, whereas significant delayed time to death (p < 0.005) was observed for three additional compounds. Remarkably, ATA was also fully protective in mice challenged with a lethal dose of BoNT/E, which also uses the SV2 receptor. This study demonstrates that receptor-binding inhibitors have the potential to serve as next generation therapeutics for botulism, and therefore the assay developed may facilitate discovery of new anti-BoNT countermeasures.

Closing the empty anti-Babesia gibsoni drug pipeline in vitro using fluorescence-based high throughput screening assay

2020 ◽  
Vol 75 ◽  
pp. 102054 ◽  
Author(s):  
Mohamed Abdo Rizk ◽  
Shengwei Ji ◽  
Mingming Liu ◽  
Shimaa Abd El-Salam El-Sayed ◽  
Yongchang Li ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Babesia Gibsoni ◽  
Screening Assay ◽  
High Throughput Screening Assay ◽  
Drug Pipeline

scholarly journals Development of a Fluorescent Assay to Search New Drugs Using Stable tdTomato-Leishmania, and the Selection of Galangin as a Candidate With Anti-Leishmanial Activity

2021 ◽  
Vol 11 ◽  
Author(s):  
María Fernanda García-Bustos ◽  
Agustín Moya Álvarez ◽  
Cecilia Pérez Brandan ◽  
Cecilia Parodi ◽  
Andrea Mabel Sosa ◽  
...  
Keyword(s):  
Active Compound ◽  
Wild Strain ◽  
Fluorescence Assay ◽  
New Drugs ◽  
Lipid Inclusion ◽  
Screening Assay ◽  
Meglumine Antimoniate ◽  
Wide Range

Antimonials continue to be considered the first-line treatment for leishmaniases, but its use entails a wide range of side effects and serious reactions. The search of new drugs requires the development of methods more sensitive and faster than the conventional ones. We developed and validated a fluorescence assay based in the expression of tdTomato protein by Leishmania, and we applied this method to evaluate the activity in vitro of flavonoids and reference drugs. The pIR1SAT/tdTomato was constructed and integrated into the genome of Leishmania (Leishmania) amazonensis. Parasites were selected with nourseothricin (NTC). The relation of L. amaz/tc3 fluorescence and the number of parasites was determined; then the growth in vitro and infectivity in BALB/c mice was characterized. To validate the fluorescence assay, the efficacy of miltefosine and meglumine antimoniate was compared with the conventional methods. After that, the method was used to assess in vitro the activity of flavonoids; and the mechanism of action of the most active compound was evaluated by transmission electron microscopy and ELISA. A linear correlation was observed between the emission of fluorescence of L. amaz/tc3 and the number of parasites (r2 = 0.98), and the fluorescence was stable in the absence of NTC. No differences were observed in terms of infectivity between L. amaz/tc3 and wild strain. The efficacy of miltefosine and meglumine antimoniate determined by the fluorescence assay and the microscopic test showed no differences, however, in vivo the fluorescence assay was more sensitive than limiting dilution assay. Screening assay revealed that the flavonoid galangin (GAL) was the most active compound with IC50 values of 53.09 µM and 20.59 µM in promastigotes and intracellular amastigotes, respectively. Furthermore, GAL induced mitochondrial swelling, lipid inclusion bodies and vacuolization in promastigotes; and up-modulated the production of IL-12 p70 in infected macrophages. The fluorescence assay is a useful tool to assess the anti-leishmanial activity of new compounds. However, the assay has some limitations in the macrophage-amastigote model that might be related with an interfere of flavanol aglycones with the fluorescence readout of tdTomato. Finally, GAL is a promising candidate for the development of new treatment against the leishmaniasis.

scholarly journals Extrapolating In Vitro Screening Assay Data for Thyroperoxidase Inhibition to Predict Serum Thyroid Hormones in the Rat

2019 ◽  
Vol 173 (2) ◽  
pp. 280-292 ◽  
Author(s):  
Iman Hassan ◽  
Hisham El-Masri ◽  
Jermaine Ford ◽  
Amanda Brennan ◽  
Sakshi Handa ◽  
...  
Keyword(s):  
Thyroid Gland ◽  
Time Course ◽  
Ex Vivo ◽  
Response Analysis ◽  
In Vitro Screening ◽  
Screening Assay ◽  
High Throughput Screening Assay ◽  
Serum T4

Abstract Thyroperoxidase (TPO) is an enzyme essential for thyroid hormone (TH) synthesis and a target site for a number of xenobiotics that disrupt TH homeostasis. An in vitro high-throughput screening assay for TPO inhibition, the Amplex UltraRed-TPO (AUR-TPO), has been used to screen the ToxCast chemical libraries for this action. Output from this assay would be most useful if it could be readily translated into an in vivo response, namely a reduction of TH in serum. To this end, the relationship between TPO inhibition in vitro and serum TH decreases was examined in rats exposed to 2 classic TPO inhibitors, propylthiouracil (PTU) and methimazole (MMI). Serum and gland PTU, MMI, and TH levels were quantified using tandem liquid chromatography mass spectrometry. Thyroperoxidase activity was determined in thyroid gland microsomes treated with PTU or MMI in vitro and ex vivo from thyroid gland microsomes prepared from exposed animals. A quantitative model was constructed by contrasting in vitro and ex vivo AUR-TPO results and the in vivo time-course and dose-response analysis. In vitro:ex vivo correlations of AUR-TPO outputs indicated that less than 30% inhibition of TPO in vitro was sufficient to reduce serum T4 by 20%, a degree of regulatory significance. Although further testing of model estimates using other TPO inhibitors is essential for verification of these initial findings, the results of this study provide a means to translate in vitro screening assay results into predictions of in vivo serum T4 changes to inform risk assessment.

Monoclonal Antibody-Based Screening Assay for Factor Inhibiting Hypoxia-Inducible Factor Inhibitors

2008 ◽  
Vol 13 (6) ◽  
pp. 494-503 ◽  
Author(s):  
Sang-Hyeup Lee ◽  
Jeong Hee Moon ◽  
Eun Ah Cho ◽  
Seong-Eon Ryu ◽  
Myung Kyu Lee
Keyword(s):  
Monoclonal Antibody ◽  
High Throughput Screening ◽  
Transcriptional Activity ◽  
Hypoxia Inducible Factor ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sensitive Assay ◽  
Screening Assay ◽  
Hypoxic Conditions

The factor-inhibiting hypoxia-inducible factor (FIH) hydroxylates the asparagine 803 (Asn803) residue of the hypoxia-inducible factor 1α (HIF-1α), and the modification abrogates the transcriptional activity of HIF-1α. Because FIH is more active on HIF-1α than prolyl hydroxylase domain proteins under hypoxic conditions, its inhibitors have potential to be developed as anti-ischemic drugs targeting normal cells stressed by hypoxia. In this study, the authors developed the first monoclonal antibody, SHN-HIF1α, specifically to Asn803 hydroxylated HIF-1α and a sensitive assay system for FIH inhibitors using the monoclonal antibody (Mab). SHN-HIF1α showed 740 times higher affinity to the Asn803 hydroxylated HIF-1α peptide than the unmodified one. An enzyme-linked immunosorbent assay—based system using SHN-HIF1α displayed at least 30 times more sensitivity than previous methods for screening FIH inhibitors and was easily applicable to develop a high-throughput screening system. SHN-HIF1α also showed an Asn803 hydroxylation-dependent specificity to HIF-1α in cells. Taken together, the results suggest that it may be used to analyze the in vivo and in vitro activities of FIH inhibitors. ( Journal of Biomolecular Screening 2008:494-503)

scholarly journals Identification of Small Molecules That Inhibit the Interaction of TEM8 with Anthrax Protective Antigen Using a FRET Assay

2013 ◽  
Vol 18 (6) ◽  
pp. 714-725 ◽  
Author(s):  
Lorna M. Cryan ◽  
Kaiane A. Habeshian ◽  
Thomas P. Caldwell ◽  
Meredith T. Morris ◽  
P. Christine Ackroyd ◽  
...  
Keyword(s):  
Blood Vessels ◽  
High Throughput ◽  
High Throughput Screening ◽  
Protective Antigen ◽  
Resonance Energy ◽  
Cysteine Residue ◽  
Tumor Formation ◽  
Screening Assay ◽  
High Throughput Screening Assay

Tumor marker endothelial 8 (TEM8) is a receptor for the protective antigen (PA) component of anthrax toxin. TEM8 is upregulated on endothelial cells lining the blood vessels within tumors, compared with normal blood vessels. A number of studies have demonstrated a pivotal role for TEM8 in developmental and tumor angiogenesis. We have also shown that targeting the anthrax receptors with a mutated form of PA inhibits angiogenesis and tumor formation in vivo. Here we describe the development and testing of a high-throughput fluorescence resonance energy transfer assay to identify molecules that strongly inhibit the interaction of PA and TEM8. The assay we describe is sensitive and robust, with a Z’ value of 0.8. A preliminary screen of 2310 known bioactive library compounds identified ebselen and thimerosal as inhibitors of the TEM8-PA interaction. These molecules each contain a cysteine-reactive transition metal, and complementary studies indicate that their inhibition of interaction is due to modification of a cysteine residue in the TEM8 extracellular domain. This is the first demonstration of a high-throughput screening assay that identifies inhibitors of TEM8, with potential application for antianthrax and antiangiogenic diseases.

Prion protein as a target for therapeutic interventions

2004 ◽  
Vol 76 (5) ◽  
pp. 915-920 ◽  
Author(s):  
P. P. Liberski
Keyword(s):  
Prion Protein ◽  
Phenotypic Expression ◽  
Therapeutic Interventions ◽  
Transmissible Spongiform Encephalopathies ◽  
Spongiform Encephalopathy ◽  
Public Health Perspective ◽  
Spongiform Encephalopathies ◽  
Mad Cow Disease

Transmissible spongiform encephalopathies (TSEs), currently known as prion diseases, are neurodegenerative disorders of the central nervous system (CNS) caused by an elusive infectious agent called “prion” (proteinaceous infectious particle). These dis orders include: kuru, Creutzfeldt –Jakob disease (CJD) and its variant (vCJD), Gerstmann–Sträussler–Scheinker (GSS) disease and fatal familial insomnia (FFI) in humans, scrapie in sheep and goats, bovine spongiform encephalopathy (BSE) or mad cow disease, and chronic wasting disease (CWD) in cervids. According to the widely accepted “prion hypothesis”, prion is an aggregate of the abnormal isoform of prion protein (PrPSc). Prion protein is a cell-derived glycoprotein (this normal isoform is called PrPc) encoded by a gene on chromosome 20 in humans (PRNP). In familial forms of TSEs, mutations within the ORF of PRNP are linked to the phenotypic expression of the disease. TSEs are important from public health perspective, and “mad cow disease has created the greatest threat to the safety of human food supply in modern times. vCJD threatens the safety of the blood supply worldwide”. Thus, to search for effective therapy is more than an urgent task. In TSEs, aggregates of PrPSc accumulate in the brain in a form of plaques, or synaptic deposits. The conversion of PrPc into PrPSc and subsequent deposits of PrPSc are targets for therapeutic interventions. These include: tricyclic compounds—acridine and phenothiazine derivatives; quinacrine; anti-PrPSc antibodies; dendrimers; polyethylene antibiotics (amphotericin B, MS-8209); pentosan polysulfate; and dextran sulfate. All these compounds are active in many in vitro and in vivo assays, but not proved definitely active in humans. Thus, albeit interesting and promising, the chemotherapy of TSEs is still in the infant phase.

scholarly journals Establishment of an In Vitro High-Throughput Screening Assay for Detecting Phospholipidosis-Inducing Potential

2005 ◽  
Vol 90 (1) ◽  
pp. 133-141 ◽  
Author(s):  
Toshihiko Kasahara ◽  
Kazuo Tomita ◽  
Hiroyuki Murano ◽  
Tsuyoshi Harada ◽  
Keisuke Tsubakimoto ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Screening Assay ◽  
High Throughput Screening Assay
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