Microtubules as a therapeutic target in Duchenne muscular dystrophy

Abstract

Microtubules (MT) are dynamic polymers of tubulin protein whose post-translational modifications regulate MT interactions with other proteins, including intermediate filaments and actin. This integrated cytoskeletal network performs a vast array of cellular functions, including cell movement, transport of cellular cargo, defining cell shape and stiffness, and transmitting mechanical information to proteins that generate biological signals (mechanotransduction). My work is in Duchenne muscular dystrophy, where the absence of dystrophin leads to the proliferation of microtubules marked by an increase in posttranslational (PTM) modifications to their tubulin including detyrosination (deTyr-tubulin) and acetylation (acetyl-tubulin). The consequences of this change are increased cytoskeletal mechanics (i.e., stiffness) of the muscle fiber and increased mechanotransduction through NADPH Oxidase 2 (Nox2) dependent reactive oxygen species (ROS) and calcium signals during contraction that together have been implicated in the contraction injury that drives the pathology. My work addressed two open questions related to the pathobiology of these microtubule changes independent of dystrophic disease (Aim 1; Chapter 2) and the potential for targeting their reduction as a therapeutic option for halting or slowing disease progression (Aim 2; Chapter 3).