Zebrafish for drug toxicity screening: bridging the in vitro cell-based models and in vivo mammalian models.
ABSTRACT INTRODUCTION: Over the past decade, zebrafish have been tasked to play important roles from modeling human diseases to finding cures for them. Inadvertently, these fish now find themselves swimming along the drug development pipeline. A number of studies have been conducted to see if these small fish are up to the task of drug toxicity testing, an important rite of passage along the pharmaceutical pipeline. AREAS COVERED: This review covers the recent publications (2008 - 2010) on the state-of-the-art applications that couple advanced technologies with the unique advantages of zebrafish for drug toxicity screening. The paper looks at the several automated high-throughput platforms that have been developed for zebrafish teratogenicity, cardiotoxicity and neuro-sensory organ toxicity assays over the past 3 years as well as the important studies related to metabolism and biotransformation of selected drugs that have been initiated. This paper also reviews their mechanistic and predictive omics applications. EXPERT OPINION: While there have been a number of developments over the past 3 years and indeed over the last 10 years, challenges and limitations still exist, which, unless overcome, will prevent zebrafish from truly reaching their full potential as a drug toxicological model. That being said, recent developments have suggested that zebrafish could play a role in bridging the gap between in vitro cell-based models and in vivo mammalian models.
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ABSTRACT: Much has been learned about vertebrate development by random mutagenesis followed by phenotypic screening and by targeted gene disruption followed by phenotypic analysis in model organisms. Because the timing of many developmental events is critical, it would be useful to have temporal control over modulation of gene function, a luxury frequently not possible with genetic mutants. Here, we demonstrate that small molecules capable of conditional gene product modulation can be identified through developmental screens in zebrafish. We have identified several small molecules that specifically modulate various aspects of vertebrate ontogeny, including development of the central nervous system, the cardiovascular system, the neural crest, and the ear. Several of the small molecules identified allowed us to dissect the logic of melanocyte and otolith development and to identify critical periods for these events. Small molecules identified in this way offer potential to dissect further these and other developmental processes and to identify novel genes involved in vertebrate development.Proceedings of the National Academy of Sciences 12/2000; 97(24):12965-9. · 9.74 Impact Factor
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ABSTRACT: Experimental and computational approaches to estimate solubility and permeability in discovery and development settings are described. In the discovery setting 'the rule of 5' predicts that poor absorption or permeation is more likely when there are more than 5 H-bond donors, 10 H-bond acceptors, the molecular weight (MWT) is greater than 500 and the calculated Log P (CLogP) is greater than 5 (or MlogP > 4.15). Computational methodology for the rule-based Moriguchi Log P (MLogP) calculation is described. Turbidimetric solubility measurement is described and applied to known drugs. High throughput screening (HTS) leads tend to have higher MWT and Log P and lower turbidimetric solubility than leads in the pre-HTS era. In the development setting, solubility calculations focus on exact value prediction and are difficult because of polymorphism. Recent work on linear free energy relationships and Log P approaches are critically reviewed. Useful predictions are possible in closely related analog series when coupled with experimental thermodynamic solubility measurements.Advanced Drug Delivery Reviews 03/2001; 46(1-3):3-26. · 12.89 Impact Factor
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ABSTRACT: The zebrafish (Danio rerio) is now the pre-eminent vertebrate model system for clarification of the roles of specific genes and signaling pathways in development. The zebrafish genome will be completely sequenced within the next 1-2 years. Together with the substantial historical database regarding basic developmental biology, toxicology, and gene transfer, the rich foundation of molecular genetic and genomic data makes zebrafish a powerful model system for clarifying mechanisms in toxicity. In contrast to the highly advanced knowledge base on molecular developmental genetics in zebrafish, our database regarding infectious and noninfectious diseases and pathologic lesions in zebrafish lags far behind the information available on most other domestic mammalian and avian species, particularly rodents. Currently, minimal data are available regarding spontaneous neoplasm rates or spontaneous aging lesions in any of the commonly used wild-type or mutant lines of zebrafish. Therefore, to fully utilize the potential of zebrafish as an animal model for understanding human development, disease, and toxicology we must greatly advance our knowledge on zebrafish diseases and pathology.Toxicologic Pathology 01/2003; 31 Suppl:62-87. · 2.06 Impact Factor