scholarly journals Screening for Small Molecule Modulators of Trypanosoma brucei Hsp70 Chaperone Activity Based upon Alcyonarian Coral-Derived Natural Products

Marine Drugs ◽  
2020 ◽  
Vol 18 (2) ◽  
pp. 81
Author(s):  
Sarah K. Andreassend ◽  
Stephen J. Bentley ◽  
Gregory L. Blatch ◽  
Aileen Boshoff ◽  
Robert A. Keyzers
Keyword(s):  
Small Molecules ◽  
Trypanosoma Brucei ◽  
Essential Role ◽  
Protozoan Parasite ◽  
Chaperone Activity ◽  
Mammalian Cell Line ◽  
Structure Activity ◽  
Hsp70 Chaperone ◽  
Small Molecule Modulators ◽  
J Protein

The Trypanosoma brucei Hsp70/J-protein machinery plays an essential role in survival, differentiation, and pathogenesis of the protozoan parasite, and is an emerging target against African Trypanosomiasis. This study evaluated a set of small molecules, inspired by the malonganenones and nuttingins, as modulators of the chaperone activity of the cytosolic heat inducible T. brucei Hsp70 and constitutive TbHsp70.4 proteins. The compounds were assessed for cytotoxicity on both the bloodstream form of T. b. brucei parasites and a mammalian cell line. The compounds were then investigated for their modulatory effect on the aggregation suppression and ATPase activities of the TbHsp70 proteins. A structure–activity relationship for the malonganenone-class of alkaloids is proposed based upon these results.

Screening for small molecule modulators of Hsp70 chaperone activity using protein aggregation suppression assays: inhibition of the plasmodial chaperone PfHsp70-1

2011 ◽  
Vol 392 (5) ◽  
Author(s):  
Ingrid L. Cockburn ◽  
Eva-Rachele Pesce ◽  
Jude M. Pryzborski ◽  
Michael T. Davies-Coleman ◽  
Peter G.K. Clark ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Small Molecule ◽  
Drug Target ◽  
Molecular Probes ◽  
Chaperone Activity ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Chaperone Function ◽  
Hsp70 Chaperone ◽  
Small Molecule Modulators

Abstract Plasmodium falciparum heat shock protein 70 (PfHsp70-1) is thought to play an essential role in parasite survival and virulence in the human host, making it a potential antimalarial drug target. A malate dehydrogenase based aggregation suppression assay was adapted for the screening of small molecule modulators of Hsp70. A number of small molecules of natural (marine prenylated alkaloids and terrestrial plant naphthoquinones) and related synthetic origin were screened for their effects on the protein aggregation suppression activity of purified recombinant PfHsp70-1. Five compounds (malonganenone A-C, lapachol and bromo-β-lapachona) were found to inhibit the chaperone activity of PfHsp70-1 in a concentration dependent manner, with lapachol preferentially inhibiting PfHsp70-1 compared to another control Hsp70. Using growth inhibition assays on P. falciparum infected erythrocytes, all of the compounds, except for malonganenone B, were found to inhibit parasite growth with IC50 values in the low micromolar range. Overall, this study has identified two novel classes of small molecule inhibitors of PfHsp70-1, one representing a new class of antiplasmodial compounds (malonganenones). In addition to demonstrating the validity of PfHsp70-1 as a possible drug target, the compounds reported in this study will be potentially useful as molecular probes for fundamental studies on Hsp70 chaperone function.

scholarly journals Identification of Small Molecule Modulators of Diguanylate Cyclase by FRET-based High-Throughput-Screening

2018 ◽  
Author(s):  
Matthias Christen ◽  
Cassandra Kamischke ◽  
Hemantha D. Kulasekara ◽  
Kathleen C. Olivas ◽  
Bridget R. Kulasekara ◽  
...  
Keyword(s):  
Small Molecules ◽  
Small Molecule ◽  
High Throughput ◽  
Biofilm Formation ◽  
High Throughput Screening ◽  
Diguanylate Cyclase ◽  
Chronic Infections ◽  
Structure Activity ◽  
Diguanylate Cyclases ◽  
Small Molecule Modulators

The bacterial second messenger cyclic diguanosine monophosphate (c-di-GMP) is a key regulator of cellular motility, the cell cycle, and biofilm formation with its resultant antibiotic tolerance, which may make chronic infections difficult to treat. Therefore, diguanylate cyclases, which regulate the spatiotemporal production of c-di-GMP, may be attractive drug targets to control biofilm formation that is part of chronic infections. In this paper, we present a FRET-based biochemical high-throughput screening approach coupled with detailed structure-activity studies to identify synthetic small molecule modulators of the diguanylate cyclase, DgcA, from Caulobacter crescentus. We identified a set of 7 small molecules that in the low µM range regulate DgcA enzymatic activity. Subsequent structure activity studies on selected scaffolds revealed a remarkable diversity of modulatory behaviors, including slight chemical substitutions that revert the effects from allosteric enzyme inhibition to activation. The compounds identified represent novel chemotypes and are potentially developable into chemical genetic tools for the dissection of c-di-GMP signaling networks and alteration of c-di-GMP associated phenotypes. In sum, our studies underline the importance for detailed mechanism of action studies for inhibitors of c-di-GMP signaling and demonstrate the complex interplay between synthetic small molecules and the regulatory mechanisms that control the activity of diguanylate cyclases.

scholarly journals Metabolic reprogramming during the Trypanosoma brucei life cycle

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 683 ◽  
Author(s):  
Terry K. Smith ◽  
Frédéric Bringaud ◽  
Derek P. Nolan ◽  
Luisa M. Figueiredo
Keyword(s):  
Life Cycle ◽  
Trypanosoma Brucei ◽  
Model Organism ◽  
Protozoan Parasite ◽  
Tsetse Fly ◽  
Metabolic Reprogramming ◽  
Mammalian Host ◽  
Insect Vector ◽  
Environmental Signals ◽  
Cellular Metabolic Activity

Cellular metabolic activity is a highly complex, dynamic, regulated process that is influenced by numerous factors, including extracellular environmental signals, nutrient availability and the physiological and developmental status of the cell. The causative agent of sleeping sickness, Trypanosoma brucei, is an exclusively extracellular protozoan parasite that encounters very different extracellular environments during its life cycle within the mammalian host and tsetse fly insect vector. In order to meet these challenges, there are significant alterations in the major energetic and metabolic pathways of these highly adaptable parasites. This review highlights some of these metabolic changes in this early divergent eukaryotic model organism.

scholarly journals Polo-like kinase is required for Golgi and bilobe biogenesis in Trypanosoma brucei

2008 ◽  
Vol 181 (3) ◽  
pp. 431-438 ◽  
Author(s):  
Christopher L. de Graffenried ◽  
Helen H. Ho ◽  
Graham Warren
Keyword(s):  
Cell Cycle ◽  
Endoplasmic Reticulum ◽  
Trypanosoma Brucei ◽  
Protozoan Parasite ◽  
Controlled Assembly

A bilobed structure marked by TbCentrin2 regulates Golgi duplication in the protozoan parasite Trypanosoma brucei. This structure must itself duplicate during the cell cycle for Golgi inheritance to proceed normally. We show here that duplication of the bilobed structure is dependent on the single polo-like kinase (PLK) homologue in T. brucei (TbPLK). Depletion of TbPLK leads to malformed bilobed structures, which is consistent with an inhibition of duplication and an increase in the number of dispersed Golgi structures with associated endoplasmic reticulum exit sites. These data suggest that the bilobe may act as a scaffold for the controlled assembly of the duplicating Golgi.

scholarly journals Structure-based drug design against Trypanosoma brucei methionyl-tRNA synthetase

2014 ◽  
Vol 70 (a1) ◽  
pp. C708-C708
Author(s):  
Cho Yeow Koh ◽  
Jasmine Nguyen ◽  
Sayaka Shibata ◽  
Zhongsheng Zhang ◽  
Ranae Ranade ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Trypanosoma Brucei ◽  
High Throughput ◽  
High Throughput Screening ◽  
Protozoan Parasite ◽  
Trna Synthetase ◽  
Structure Based Drug Design ◽  
Chemical Structures ◽  
Ic50 Values ◽  
Methionyl Trna Synthetase

Infection by the protozoan parasite Trypanosoma brucei causes human African trypanosomiasis, commonly known as sleeping sickness. The disease is fatal without treatment; yet, current therapeutic options for the disease are inadequate due to toxicity, difficulty in administration and emerging resistance. Therefore, methionyl-tRNA synthetase of T. brucei (TbMetRS) is targeted for the development of new antitrypanosomal drugs. We have recently completed a high-throughput screening campaign against TbMetRS using a 364,131 compounds library in The Scripps Research Institute Molecular Screening Center. Here we outline our strategy to integrate the power of crystal structures with high-throughput screening in a drug discovery project. We applied the rapid crystal soaking procedure to obtain structures of TbMetRS in complex with inhibitors reported earlier[1] to approximately 70 high-throughput screening hits. This resulted in more than 20 crystal structures of TbMetRS·hit complexes. These hits cover a large diversity of chemical structures with IC50 values between 200 nM and 10 µM. Based on the solved structures and existing knowledge drawn from other in-house inhibitors, the IC50 value of the most promising hit has been improved. Further development of the compounds into potent TbMetRS inhibitors with desirable pharmacokinetic properties is on-going and will continue to benefit from information derived from crystal structures.

The structural mechanics of cell division in Trypanosoma brucei

2008 ◽  
Vol 36 (3) ◽  
pp. 421-424 ◽  
Author(s):  
Sue Vaughan ◽  
Keith Gull
Keyword(s):  
Cell Division ◽  
Trypanosoma Brucei ◽  
Mammalian Cells ◽  
Reverse Genetics ◽  
Protozoan Parasite ◽  
Cell Types ◽  
Single Copy ◽  
Structural Mechanics ◽  
Sub Saharan Africa ◽  
Mammalian Host

Undoubtedly, there are fundamental processes driving the structural mechanics of cell division in eukaryotic organisms that have been conserved throughout evolution and are being revealed by studies on organisms such as yeast and mammalian cells. Precision of structural mechanics of cytokinesis is however probably no better illustrated than in the protozoa. A dramatic example of this is the protozoan parasite Trypanosoma brucei, a unicellular flagellated parasite that causes a devastating disease (African sleeping sickness) across Sub-Saharan Africa in both man and animals. As trypanosomes migrate between and within a mammalian host and the tsetse vector, there are periods of cell proliferation and cell differentiation involving at least five morphologically distinct cell types. Much of the existing cytoskeleton remains intact during these processes, necessitating a very precise temporal and spatial duplication and segregation of the many single-copy organelles. This structural precision is aiding progress in understanding these processes as we apply the excellent reverse genetics and post-genomic technologies available in this system. Here we outline our current understanding of some of the structural aspects of cell division in this fascinating organism.

scholarly journals SAR by kinetics for drug discovery in protein misfolding diseases

2018 ◽  
Vol 115 (41) ◽  
pp. 10245-10250 ◽  
Author(s):  
Sean Chia ◽  
Johnny Habchi ◽  
Thomas C. T. Michaels ◽  
Samuel I. A. Cohen ◽  
Sara Linse ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Small Molecules ◽  
Protein Misfolding ◽  
Amyloid Beta Peptide ◽  
Oligomer Formation ◽  
Chemical Derivatives ◽  
Structure Activity ◽  
Beta Peptide ◽  
Misfolding Diseases ◽  
Aβ Oligomer

To develop effective therapeutic strategies for protein misfolding diseases, a promising route is to identify compounds that inhibit the formation of protein oligomers. To achieve this goal, we report a structure−activity relationship (SAR) approach based on chemical kinetics to estimate quantitatively how small molecules modify the reactive flux toward oligomers. We use this estimate to derive chemical rules in the case of the amyloid beta peptide (Aβ), which we then exploit to optimize starting compounds to curtail Aβ oligomer formation. We demonstrate this approach by converting an inactive rhodanine compound into an effective inhibitor of Aβ oligomer formation by generating chemical derivatives in a systematic manner. These results provide an initial demonstration of the potential of drug discovery strategies based on targeting directly the production of protein oligomers.

Quantitative Structure Activity Relationship (QSAR) study predicts small molecule binding to RNA structure

2021 ◽  
Author(s):  
Zhengguo Cai ◽  
Martina Zafferani ◽  
Olanrewaju Akande ◽  
Amanda Hargrove
Keyword(s):  
High Resolution ◽  
Small Molecules ◽  
Small Molecule ◽  
Rna Structure ◽  
Quantitative Structure ◽  
Rna Structures ◽  
Qsar Study ◽  
Structure Activity ◽  
Qsar Models ◽  
Hiv 1

The diversity of RNA structural elements and their documented role in human diseases make RNA an attractive therapeutic target. However, progress in drug discovery and development has been hindered by challenges in the determination of high-resolution RNA structures and a limited understanding of the parameters that drive RNA recognition by small molecules, including a lack of validated quantitative structure-activity relationships (QSAR). Herein, we developed QSAR models that quantitatively predict both thermodynamic and kinetic-based binding parameters of small molecules and the HIV-1 TAR model RNA system. A set of small molecules bearing diverse scaffolds was screened against the HIV-1-TAR construct using surface plasmon resonance, which provided the binding kinetics and affinities. The data was then analyzed using multiple linear regression (MLR) combined with feature selection to afford robust models for binding of diverse RNA-targeted scaffolds. The predictivity of the model was validated on untested small molecules. The QSAR models presented herein represent the first application of validated and predictive 2D-QSAR using multiple scaffolds against an RNA target. We expect the workflow to be generally applicable to other RNA structures, ultimately providing essential insight into the small molecule descriptors that drive selective binding interactions and, consequently, providing a platform that can exponentially increase the efficiency of ligand design and optimization without the need for high-resolution RNA structures.

Human African trypanosomiasis

2010 ◽  
pp. 1119-1127
Author(s):  
August Stich
Keyword(s):  
West Africa ◽  
East Africa ◽  
Trypanosoma Brucei ◽  
Human African Trypanosomiasis ◽  
Protozoan Parasite ◽  
Sleeping Sickness ◽  
Tsetse Flies ◽  
African Trypanosomiasis ◽  
Tropical Africa

Human African trypanosomiasis (HAT, sleeping sickness) is caused by two subspecies of the protozoan parasite Trypanosoma brucei: T. b. rhodesiense is prevalent in East Africa among many wild and domestic mammals; T. b. gambiense causes an anthroponosis in Central and West Africa. The disease is restricted to tropical Africa where it is transmitted by the bite of infected tsetse flies (...

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