Development of Novel Chemical Biology Tools to Probe Malaria Parasite Physiology and Aid in Antimalarial Drug Discovery

Development of Novel Chemical Biology Tools to Probe Malaria Parasite Physiology and Aid in Antimalarial Drug Discovery
Author: James Robbins Abshire
Publisher:
Total Pages: 117
Release: 2015
Genre:
ISBN:

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Malaria remains a major burden to global public health. Antimalarial drugs are a mainstay in efforts to control and eventually eradicate this disease. However, increasing drug resistance threatens to reverse recent gains in malaria control, making the discovery of new antimalarials critical. Antimalarial discovery is especially challenging due to the unique biology of malaria parasites, the scarcity of tools for identifying new drug targets, and the poorly understood mechanisms of action of existing antimalarials. Therefore, this work describes the development of two chemical biology tools to address unmet needs in antimalarial drug discovery. A particular challenge in antimalarial development is a shortage of validated parasite drug targets. Potent antimalarials with demonstrated clinical efficacy, like the aminoquinolines and artemisinins, represent a promising basis for rational drug development. Unfortunately, the molecular targets of these drugs have not been identified. While both are thought to interact with parasite heme, linking in vitro heme binding with drug potency remains challenging because labile heme is difficult to quantify in live cells. This work presents a novel genetically-encoded heme biosensor and describes its application to quantify labile heme in live malaria parasites and test mechanisms of antimalarial action. Another challenge is posed by the widespread malaria parasite Plasmodium vivax, which, unlike P. falciparum, cannot be propagated in vitro, hindering research into parasite biology and drug target identification. P. vivax preferentially invades reticulocytes, which are impractical to obtain in continuous supply. The basis for this invasion tropism remains incompletely understood, mainly because current tools cannot directly link molecular binding events to invasion outcomes. This work presents novel methods for immobilizing synthetic receptors on the red blood cell surface. These receptors are used in proof-of-concept experiments to investigate requirements for efficient invasion via a well-characterized P. falciparum invasion pathway, suggesting this method can be used to elucidate molecular mechanisms underlying parasite invasion tropisms. Future receptor designs could promote the invasion of P. vivax into mature red blood cells and potentially facilitate practical in vitro culture. Taken together, these tools present new opportunities for drug discovery to aid efforts in malaria control and eventual eradication.

Malaria

Malaria
Author: Institute of Medicine
Publisher: National Academies Press
Total Pages: 312
Release: 1991-02-01
Genre: Medical
ISBN: 9780309045278

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Malaria is making a dramatic comeback in the world. The disease is the foremost health challenge in Africa south of the Sahara, and people traveling to malarious areas are at increased risk of malaria-related sickness and death. This book examines the prospects for bringing malaria under control, with specific recommendations for U.S. policy, directions for research and program funding, and appropriate roles for federal and international agencies and the medical and public health communities. The volume reports on the current status of malaria research, prevention, and control efforts worldwide. The authors present study results and commentary on the: Nature, clinical manifestations, diagnosis, and epidemiology of malaria. Biology of the malaria parasite and its vector. Prospects for developing malaria vaccines and improved treatments. Economic, social, and behavioral factors in malaria control.

Reflections on a Century of Malaria Biochemistry

Reflections on a Century of Malaria Biochemistry
Author: Irwin Sherman
Publisher: Academic Press
Total Pages: 417
Release: 2011-08-29
Genre: Medical
ISBN: 0080921833

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Malaria is one of the most common infectious diseases and an enormous public health problem. Each year it causes disease in approximately 650 million people and kills between 1 and 3 million, most of them young children in Sub-Saharan Africa. This book provides an overview of the research that has been done in malaria biochemistry in the quest to find a cure. It discusses how our understanding has helped us to develop better diagnostics and novel chemotherapies. Researchers will find having all of this information in one volume, annotated with personal reflections from a leader in the field, invaluable given the big push being made on various fronts to use the latest drug discovery tools to attack malaria and other developing country diseases. Reviews the past 100 years of malaria biochemistry research providing researchers with an overview of the investigations that have been undertaken in this field Chronicles both biochemical successes and failures

Advances in Malaria Research

Advances in Malaria Research
Author: Deepak Gaur
Publisher: John Wiley & Sons
Total Pages: 1116
Release: 2016-11-30
Genre: Science
ISBN: 1118493826

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Thoroughly reviews our current understanding of malarial biology Explores the subject with insights from post-genomic technologies Looks broadly at the disease, vectors of infection, and treatment and prevention strategies A timely publication with chapters written by global researchers leaders

Drug Development for Malaria

Drug Development for Malaria
Author: Pravin Kendrekar
Publisher: John Wiley & Sons
Total Pages: 404
Release: 2022-08-15
Genre: Medical
ISBN: 3527348603

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Drug Development for Malaria Provides readers with first-hand advice for the development of novel antimalarial drugs This book provides a systematic overview of antimalarial drug development and presents a wealth of data and insight from drug developers across three continents, including many from countries where the disease is endemic. Throughout, the contributions have been written with the drug developer in mind, highlighting challenges but also opportunities for the successful development of effective antimalarial drugs. Case studies and method-oriented chapters provide an abundance of practical first-hand advice on how to successfully develop an antimalarial drug. Key topics covered in the book include: The performance of current drugs and therapies, the influence of formulation and targeted delivery, and strategies to overcome drug resistance. Technologies and approaches for development of novel drugs, such as assays, computer-aided drug design, known and potential drug targets, and natural sources for novel antimalarial compounds Vaccination as an alternative to drug therapy For chemists and other professionals working in industries related to medicine and pharmaceuticals, this book provides a completely comprehensive overview of the current state of novel antimalarial drugs and how they can be developed in an efficient and cost-effective manner.

Emergence of In Vitro 3D Systems to Model Human Malaria

Emergence of In Vitro 3D Systems to Model Human Malaria
Author: Kasem Kulkeaw
Publisher: Springer Nature
Total Pages: 99
Release: 2023-05-29
Genre: Medical
ISBN: 9819906911

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This book illustrates the importance and advances of the disease model for malaria, a globally affected public health problem. This book provides comprehensive information on the malaria biology in a liver and all in vitro platforms for liver-stage malaria, including principles, protocols, applications for disease modeling and drug screening, and their limitations. The initial chapter describes the basis of stem cells in liver generation during development and in adults. The subsequent chapters highlight recent and emerging advances in liver organoid and liver-on-a-chip in modeling malaria. The book presents current protocols and methods to generate liver organoid and liver-on-a-chip together with their advantages and limitations. Toward the end, the book examines the humanized mouse model of liver-stage malaria using ectopic artificial livers regarding novel readout modalities. The recent advancement and challenges in combining liver-on-a-chip technology with biosensors are highlighted for assessing hepatocyte development viability and functions. The book elucidates the potential of these 3D models to understand the biological complexity of cellular and molecular mechanisms involved in Plasmodium development in the liver, toolboxes to investigate parasite deployment in the 3D models, and to implement in drug discovery. Finally, the book discusses the future directions and challenges in the applications of liver organoids and liver on-chip in the biology of live-stage malaria. This book is helpful for researchers and scientists in the field of parasitology, cell biology, tissue engineering, and pharmacology.​

Antimalarial Drug Discovery and Target Identification from Phenotypic High-throughput Screening Hits

Antimalarial Drug Discovery and Target Identification from Phenotypic High-throughput Screening Hits
Author: Matthew Abraham
Publisher:
Total Pages: 104
Release: 2020
Genre:
ISBN:

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The drive to propagate a species genes is among the strongest biological forces, shared by humans and pathogens alike. For pathogens like Plasmodium parasites, the etiological agent of human malaria, self-preservation comes at the cost of hundreds of thousands of human lives annually. Between 2000 and 2016, worldwide cases of malaria were progressively declining. Although there are many causes for the recent increase in global malaria cases, parasite drug resistance is a likely contributor. Thus, research is desperately needed to identify druggable targets and develop novel therapeutics capable of more than symptom alleviation. This dissertation highlights the use of key strategies that have resulted in new preclinical drug candidates, namely the systematic investigation of vast small molecule libraries. In Chapter 1, the investigation of more than 100 marine derived natural products identified six compounds with promising antiparasitic activity and selectivity relative to the host cell. Additionally, this chapter describes the successful target identification of choice screening hits, such as hectochlorin and its newly validated target, actin. In Chapter 2 high throughput screening methods are embraced to explore the activity of nearly 70,000 small molecules, testing them, with collaborators, against all malaria parasite stages that dwell in the human host. Hundreds of these molecules are discovered to have activity against one or more of these stages. Studies in collaboration with Manu Vanaerschot show the target of one such molecule acting within the mitochondrial electron transport chain, against cytochrome bc1. Despite affecting a well-characterized drug target in Plasmodium, this target rediscovery legitimizes our strategy for antimalarial hit selection from untested chemical libraries. Because drug target discovery is vital to the development of novel therapeutics, and can guide drug design to minimize the likelihood of off target effects, Chapter 3 describes the search for the target of a potent asexual blood stage (ABS) inhibitor. Here, the protein cytoplasmic isoleucyl-tRNA synthetase (PF3D7_1332900) is shown as the target of a drug-like scaffold, TCMDC-124553. This protein was previously shown to be critical in P. falciparum ABS, and our data also suggest it is essential in the liver stage of infection as well.

Antimalarial Natural Products

Antimalarial Natural Products
Author: A. Douglas Kinghorn
Publisher: Springer
Total Pages: 0
Release: 2023-01-05
Genre: Science
ISBN: 9783030898755

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This volume begins with a short history of malaria and follows with a summary of its biology. It then traces the fascinating history of the discovery of quinine for malaria treatment, and then describes quinine’s biosynthesis, its mechanism of action, and its clinical use, concluding with a discussion of synthetic antimalarial agents based on quinine’s structure. It also covers the discovery of artemisinin and its development as the source of the most effective current antimalarial drug, including summaries of its synthesis and biosynthesis, its mechanism of action, and its clinical use and resistance. A short discussion of other clinically used antimalarial natural products leads to a detailed treatment of additional natural products with significant antiplasmodial activity, classified by compound type. Although the search for new antimalarial natural products from Nature’s combinatorial library is challenging, it is very likely to yield new antimalarial drugs. This book thus ends by identifying ten natural products with development potential as clinical antimalarial agents.

Antimalarial Drug Design

Antimalarial Drug Design
Author: Alexandre Lawrenson
Publisher:
Total Pages:
Release: 2012
Genre:
ISBN:

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Malaria is a life-threatening disease which is responsible for roughly one million deaths annually. Previous successes in attempting to eradicate the disease have only been short lived, owing to the increased development of resistance in the parasite. There is a continued need for novel compounds which act at novel therapeutic targets, with the Plasmodium falciparum cytochrome bc1 complex (Pfbc1) representing one such target. Its inhibition halts the biochemical generation of ATP, thus resulting in parasite cell death. Work described in this thesis was concerned with utilising molecular modelling, synthesis and biological testing to develop novel antimalarial compounds, which selectively inhibit this target. The structural details of a number of compounds known to be active or inactive against Pfbc1 were used in combination with six different ligand based virtual screening techniques, and applied to the ZINC lead like library of compounds to identify potential chemotypes active against malaria. These methods included fingerprint similarity searching, principal component analysis, and naïve Bayesian classification. The hits from each of these methods were merged and formed part of a consensus analysis in which compounds identified across several methods were deemed of more interest than those which appeared less frequently. Each molecule was given a score based on its occurrence in the virtual screening methods and also its physicochemical properties. Compounds were filtered to remove those with unfavourable chemical properties, or which contained known toxicophores. 19 compounds were ultimately purchased and tested in vitro against the 3D7 strain of the malaria parasite. 5 of the compounds reported single digit μM IC50 values, with each containing novel structural chemotypes. The lead candidate contained a benzothiazole core, and reported an IC50 value against 3D7 of 4.53 ± 1.86 μM. Additional testing showed the compounds to be inactive against bovine bc1, which is promising as strong bovine bc1 inhibition has been shown to be indicative of cardiotoxicity in humans. Molecular docking was extensively employed to rationalise the activity of Pfbc1 inhibitors such as atovaquone and HDQ. A number of quinolone containing compounds were also subject to docking, with key observations made with regard to interactions thought to be crucial to their antimalarial activity. The hits from LBVS were also the focus of docking, further supporting their potential as Pfbc1 inhibitors. QSARs were developed for a series of 4-aminoquinoline compounds which had been tested against both the NF54 and K1 strains of malaria. MLR, PLS and kNN machine learning methods were investigated, with molecular descriptors contained within valid models interpreted. Significant models were identified and shown to have strong predictive abilities for both strains. QSAR models were similarly developed for a series of thiazolide compounds with activity against hepatitis C. SVM was found to give a significant model which was able to predict the cell safety of the thiazolide derivatives. The rational design of the novel pyrroloquinolone chemotype led to the synthesis of 7 synthetic analogues to investigate its SAR, via alkylation and Winterfeldt oxidation reactions. The compounds reported 3D7 activity values between 75 nM and 1.02 μM, with molecular docking supporting their potential for Qo binding and thus Pfbc1 inhibition.