Notably, using both surgical denervation and the neuromuscular disease amyotrophic lateral sclerosis (ALS) model, we found that elevated levels of HDAC4 are required for efficient repression of MEF2-dependent structural gene expression, indicating a link between the pathological induction of HDAC4 and subsequent MEF2 target gene suppression

Notably, using both surgical denervation and the neuromuscular disease amyotrophic lateral sclerosis (ALS) model, we found that elevated levels of HDAC4 are required for efficient repression of MEF2-dependent structural gene expression, indicating a link between the pathological induction of HDAC4 and subsequent MEF2 target gene suppression. expression of HDAC4 in muscle mass fibers is sufficient Aglafoline to induce muscle mass damage in mice. Our study identifies HDAC4 as an activity-dependent regulator of MEF2 function and suggests that activation of HDAC4 in response to chronically reduced neural activity suppresses MEF2-dependent gene expression Rabbit polyclonal to ADPRHL1 and contributes to progressive muscle mass dysfunction observed in neuromuscular diseases.Cohen, T. J., Barrientos, T., Hartman, Z. C., Garvey, S. M., Cox, G. A., Yao, T.-P. The deacetylase HDAC4 controls myocyte enhancing factor-2 dependent structural gene expression in response to neural activity. in mature skeletal muscle mass has not been fully characterized. One critical factor that regulates MEF2 activity is usually neural input. Analysis of MEF2-LacZ transgenic mice showed that prolonged motor nerve activation or exercise training can activate MEF2 transcriptional activity (5). In agreement with this observation, the MEF2-dependent expression of slow myosin light chain (MLC-slow) requires proper innervation (6). These studies uncover a functional link between neural input and MEF2 activity; however, the mechanism by which neural activity regulates MEF2 function is not well comprehended. Cell-based studies (7, 8) have shown that histone deacetylase 4 (HDAC4) binds and inactivates MEF2. Accordingly, HDAC4 and HDAC5 were thought to act as repressors of muscle mass differentiation by virtue of their inhibitory effect on MEF2. Interestingly, however, HDAC4 was found to be imported rather than exported from your nucleus on C2C12 myotube differentiation (8). This obtaining is not consistent with a simple model that HDAC4 represses muscle mass differentiation. Rather it suggests that HDAC4 plays an active role in mature skeletal muscle mass. Supporting this hypothesis, we (9) recently found that HDAC4 is usually highly induced and accumulates in the nuclei of denervated muscle mass including neuromuscular diseases such as amyotrophic lateral sclerosis (ALS). These findings led us to propose that HDAC4 is usually a key effector that controls muscle mass gene transcription in response to neural activity. Indeed, HDAC4 regulates synaptic gene expression in response to neural activity (9). However, the functional significance of HDAC4 induction and its pathological implications have not been fully established. Given that HDAC4 activity can be pharmacologically inhibited, elucidating a role for HDAC4 in muscle mass dysfunction could provide potential therapeutic opportunity for these devastating diseases. In this study, we recognized a subset of muscle mass contractile and Aglafoline structural genes as transcriptional targets of HDAC4. We show that HDAC4-dependent repression of muscle mass gene expression occurs in both cultured myotubes and skeletal muscle mass value of 0.01. Genes were further filtered by fold change from controls. Statistically significant overrepresentation in Gene Ontology categories of significantly up-regulated or repressed genes was checked using the Database for Aglafoline Annotation, Visualization and Integrated Discovery (http://david.abcc.ncifcrf.gov/) using previously described methods (11). Chromatin immunoprecipitation (ChIP) assay ChIP assay was performed on C2C12 myotubes as explained previously (12). C2C12 myotubes were crosslinked in 1.42% formaldehyde for 15 min at room temperature. Glycine (125 mM) was added to quench formaldehyde. Cells were scraped, centrifuged, and washed twice with chilly PBS. Cells were lysed with IP buffer (150 mM NaCl; 50 mM Tris, pH 7.5; 5 mM EDTA; 0.5% Nonidet P-40; and 1% Triton) by being resuspended several times and centrifuged 1 min high speed. Nuclear pellet was washed once with IP buffer, and chromatin was sheared by sonication (30 s on, 30 s on ice, 7 rounds) using Branson Sonifier 100 (Branson, Danbury, CT, USA). Samples were divided into fourths and immunoprecipitated overnight using 2 g immunoglobulin G (IgG), HDAC4, or MEF2 antibodies (Santa Cruz Biotechnology, Santa Cruz, CA, USA). Beads were washed 5 to 6 occasions with chilly IP buffer and then eluted with elution buffer (1% SDS, 0.1 M NaHCO3) at room temp for 15 min..