Impact of TIEG1 on the structural properties of fast- and slow-twitch skeletal muscle

Introduction: Transforming growth factor-beta (TGF-β)–inducible early gene-1 (TIEG1) is a transcription factor that is highly expressed in skeletal muscle. The purpose of this study was to characterize the structural properties of both fast-twitch (EDL) and slow-twitch (soleus) muscles in the hindlimb of TIEG1-deficient (TIEG1^−/−) mice. Methods: Ten slow and 10 fast muscles were analyzed from TIEG1^−/− and wild-type (WT) mice using MRI texture (MRI-TA) and histological analyses. Results: MRI-TA could discriminate between WT slow and fast muscles. Deletion of the TIEG1 gene led to changes in the texture profile within both muscle types. Specifically, muscle isolated from TIEG1^−/− mice displayed hypertrophy, hyperplasia, and a modification of fiber area distribution. Conclusions: We demonstrated that TIEG1 plays an important role in the structural properties of skeletal muscle. This study further implicates important roles for TIEG1 in the development of skeletal muscle and suggests that defects in TIEG1 expression and/or function may be associated with muscle disease. Muscle Nerve 55: 410–416, 2017.