Zebrafish Assays for Identifying Potential Muscular Dystrophy Drug Candidates - Zebrafish: Methods for Assessing Drug Safety and Toxicity - page 225

Chapter 18
Zebrafish Assays for
Identifying Potential
Muscular Dystrophy
Drug Candidates
Jian Tang, Susie Tang, Maryann Haldi, and Wen Lin Seng
Phylonix, Cambridge, MA, USA
18.1 INTRODUCTION
The aims of this research were to (1) develop a reproducible zebrafish muscular
dystrophy (MD) animal model and (2) optimize a battery of zebrafish assays to
identify potential drug candidates. In this research, we used short interfering RNA
(siRNA) injection to knockdown dystroglycan, known to be involved in muscle cell
integrity and function, and generated phenotypes consistent with those observed in
mdx mice, a naturally occurring dystrophin mutant. Next, we developed assays to
assess myotome length, muscle structure, level of ROS, and motility inMD zebrafish.
Using histology, we also confirmed muscular dystrophy disease progression. In
addition, we showed that two drugs, prednisone and epigallocatechin-3-gallate
(EGCG), which improve muscle strength in both Duchenne muscular dystrophy
patients and the mdx mouse model (Bonifati et al., 2000; Dorchies et al., 2006),
partially inhibited disease progression in MD zebrafish. Although zebrafish is
phylogenetically distant from humans, key gene families are conserved and dystro-
glycan knockdown (KD), performed by injecting siRNA into wild-type animals, is
highly specific. This study highlights the convenience of generating zebrafish disease
models and describes a variety of complementary whole animal assays for
drug screening.