Poster abstracts
Poster number 22 submitted by Geremy Lerma
Investigating the impact of TGF-β signaling on the zebrafish model of Duchenne Muscular Dystrophy
Geremy T. Lerma (Department of Molecular Genetics, The Ohio State University), Natalie M. Aloi (Molecular, Cellular, and Developmental Biology Graduate Program, Department of Molecular Genetics, The Ohio State University), Kamorah R. Ryhlick, Erin Miller (Department of Biology, The Ohio State University), Joseph Beljan (Molecular, Cellular, and Developmental Biology Graduate Program, The Ohio State University), Jared C. Talbot (School of Biology and Ecology, The University of Maine), Sharon L. Amacher (Department of Molecular Genetics, Department of Biological Chemistry and Pharmacology, The Ohio State University)
Abstract:
Duchenne muscular dystrophy (DMD), the most common form of childhood muscular dystrophy, is a progressive muscle wasting disease for which there is no cure. DMD is caused by mutation of the dystrophin gene that results in absence of the dystrophin protein. Absence of dystrophin increases muscle fragility that causes repeated rounds of muscle degeneration and regeneration ultimately leading to loss of muscle function. Transforming Growth Factor β (TGFβ) has emerged as a key factor mediating muscular dystrophy disease severity. TGFβ is an anti-inflammatory, pro-fibrotic cytokine that when chronically activated as in DMD, stimulates inflammation and fibrotic tissue accumulation, thus driving disease severity. Genome wide association studies (GWAS) have uncovered cis-regulatory modifier alleles of TGFβ regulatory proteins, that decrease their expression, and confer decreased TGFβ bioavailability and disease severity. Two of these modifier genes encode Latent TGFβ Binding Protein 4 (LTBP4) and Thrombospondin 1 (THBS1). To model these modifiers, we are using pharmacological and genetic approaches in the zebrafish DMD (dmd) model to investigate how TGFβ signaling influences dmd muscle structure, function, and dmd mutant survivorship. Transient inhibition of TGFβ results in significant and sustained rescue of muscle structure in dmd mutants when compared to DMSO-treated controls. dmd mutant zebrafish exhibit decreased movement frequency and loss of wild-type movement behaviors. Homozygous ltbp4;dmd and thbs1b;dmd double mutants show increased survivorship compared to dmd single mutant siblings. In addition, we are using CRISPR/Cas-9 based mutagenesis to generate F0 kncok-outs of putative cis-regulatory DMD modifiers that influence TGFβ signaling to assess their contribution to dmd severity. The long-term goal is to understand how TGFβ influences muscle repair and regeneration processes and identify which cell populations play a critical role in regulating these processes.
Keywords: Zebrafish, TGFbeta, Duchenne Muscular Dystrophy