In vitro Studies of Myofibers and Their Use in Analyzing the Differential Dynamics and Properties of α-Actinin Isoforms

Abstract

Skeletal muscle is a highly organized tissue that requires cooperation of many different structures and components for proper function. We explored the use of a flexor digitorum brevis (FDB) myofiber culture system to better model highly differentiated aspects of skeletal muscle in an in vitro system. Indirect immunofluorescence of FDB myofibers allowed us to better determine the subcellular localization of KLHL41, a new nemaline myopathy (NM) gene product, to ER-like subdomains of the sarcoplasmic retiuculum. By comparing FDB myofibers from wild type and myotubularin knockout mice with X-linked myotubular myopathy (XLMTM), we were also able to analyze satellite cell populations, showing that the knockout mice suffered a marked decrease in associated myogenic satellite cells. This supports concurrent data from our lab indicating a disease progression-related increase in apoptosis and a decrease in satellite cell proliferation in XLMTM.