Disease Affects Bdnf Expression in Synaptic and Extrasynaptic Regions of Skeletal Muscle of Three SBMA Mouse Models.
Spinal bulbar muscular atrophy (SBMA) is a slowly progressive, androgen-dependent neuromuscular disease in men that is characterized by both muscle and synaptic dysfunction. Because gene expression in muscle is heterogeneous, with synaptic myonuclei expressing genes that regulate synaptic function and extrasynaptic myonuclei expressing genes to regulate contractile function, we used quantitative PCR to compare gene expression in these two domains of muscle from three different mouse models of SBMA: the "97Q" model that ubiquitously expresses mutant human androgen receptor (AR), the 113Q knock-in (KI) model that expresses humanized mouse AR with an expanded glutamine tract, and the "myogenic" model that overexpresses wild-type rat AR only in skeletal muscle. We were particularly interested in neurotrophic factors because of their role in maintaining neuromuscular function via effects on both muscle and synaptic function, and their implicated role in SBMA. We confirmed previous reports of the enriched expression of select genes (e.g., the acetylcholine receptor) in the synaptic region of muscle, and are the first to report the synaptic enrichment of others (e.g., glial cell line-derived neurotrophic factor). Interestingly, all three models displayed comparably dysregulated expression of most genes examined in both the synaptic and extrasynaptic domains of muscle, with only modest differences between regions and models. These findings of comprehensive gene dysregulation in muscle support the emerging view that skeletal muscle may be a prime therapeutic target for restoring function of both muscles and motoneurons in SBMA.
['Halievski|Katherine|K|0000-0003-0365-5953', 'Nath|Samir R|SR|', 'Katsuno|Masahisa|M|0000-0001-9453-9311', 'Adachi|Hiroaki|H|0000-0002-9302-4663', 'Sobue|Gen|G|', 'Breedlove|S Marc|SM|', 'Lieberman|Andrew P|AP|', 'Jordan|Cynthia L|CL|']
D000818:Animals D019208:Brain-Derived Neurotrophic Factor D004195:Disease Models, Animal D020869:Gene Expression Profiling D005786:Gene Expression Regulation D055879:Gene Knock-In Techniques D006801:Humans D008297:Male D051379:Mice D008822:Mice, Transgenic D018482:Muscle, Skeletal D009134:Muscular Atrophy, Spinal D051381:Rats D011944:Receptors, Androgen
synaptic extrasynaptic muscle SBMA gene expression neurotrophic factors