Project description:To assess the effects of histone deacetylase (HDAC) inhibitor, HDACi 4b, treatment on muscle function on a molecular level, we performed microarray analysis on skeletal muscle (gastrocnemius) samples from wt and N17182Q mice treated with the HDAC inhibitor 4b for 3 months (50 mg/kg; s.c. injection 3x weekly; n=4 per group). The transcriptome pattern in N17182Q mice compared to wt controls consisted of deficits in the expression of genes related to mitochondrial function and oxidative metabolism. In addition, we noted that numerous genes associated with basal contractile function were altered in HD N17182Q mice. These include genes related to the muscle contractile complex, Tnnt3 and Myh8, as well as several additional myosin genes: myosin heavy chain genes, Myh10 and Myh4, and myosin light chain genes, Myl1, Mylc2 and Mylk. These findings implicate deficits in the underlying contractile function in skeletal muscle from HD mice. Further, we found robust effects of 4b treatment on the expression of genes in skeletal muscle, with 556 genes showing significantly altered expression, at p<0.005, in 4b-treated N17182Q muscle compared to vehicle-treated control mice. n=4 vehicle-treated WT mice, n=5 HDACi 4b-treated WT mice, n=4 vehicle-treated N17182Q transgenic mice, and n=3 HDACi 4b-treated N17182Q transgenic mice.
Project description:To assess the effects of histone deacetylase (HDAC) inhibitor, HDACi 4b, treatment on muscle function on a molecular level, we performed microarray analysis on skeletal muscle (gastrocnemius) samples from wt and N17182Q mice treated with the HDAC inhibitor 4b for 3 months (50 mg/kg; s.c. injection 3x weekly; n=4 per group). The transcriptome pattern in N17182Q mice compared to wt controls consisted of deficits in the expression of genes related to mitochondrial function and oxidative metabolism. In addition, we noted that numerous genes associated with basal contractile function were altered in HD N17182Q mice. These include genes related to the muscle contractile complex, Tnnt3 and Myh8, as well as several additional myosin genes: myosin heavy chain genes, Myh10 and Myh4, and myosin light chain genes, Myl1, Mylc2 and Mylk. These findings implicate deficits in the underlying contractile function in skeletal muscle from HD mice. Further, we found robust effects of 4b treatment on the expression of genes in skeletal muscle, with 556 genes showing significantly altered expression, at p<0.005, in 4b-treated N17182Q muscle compared to vehicle-treated control mice.
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from Mus musculus tissues (Heart, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from Mus musculus tissues (Heart, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:Transcriptional dysregulation has emerged as a core pathologic feature of Huntington's disease (HD), one of several triplet-repeat disorders characterized by movement deficits and cognitive dysfunction. Although the mechanisms contributing to the gene expression deficits remain unknown, therapeutic strategies have aimed to improve transcriptional output via modulation of chromatin structure. Recent studies have demonstrated therapeutic effects of commercially available histone deacetylase (HDAC) inhibitors in several HD models; however, the therapeutic value of these compounds is limited by their toxic effects. Here, beneficial effects of a novel pimelic diphenylamide HDAC inhibitor, HDACi 4b, in an HD mouse model are reported. Chronic oral administration of HDACi 4b, beginning after the onset of motor deficits, significantly improved motor performance, overall appearance, and body weight of symptomatic R6/2(300Q) transgenic mice. These effects were associated with significant attenuation of gross brain-size decline and striatal atrophy. Microarray studies revealed that HDACi 4b treatment ameliorated, in part, alterations in gene expression caused by the presence of mutant huntingtin protein in the striatum, cortex, and cerebellum of R6/2(300Q) transgenic mice. For selected genes, HDACi 4b treatment reversed histone H3 hypoacetylation observed in the presence of mutant huntingtin, in association with correction of mRNA expression levels. These findings suggest that HDACi 4b, and possibly related HDAC inhibitors, may offer clinical benefit for HD patients and provide a novel set of potential biomarkers for clinical assessment. Analysis of striatum, cortex, and cerebellum from R6/2(300Q) transgenic mice before and after treatment with the HDAC inhibitor 4b
Project description:We analyzed the functional role of DOR (Diabetes and Obesity Regulated gene) (also named Tp53inp2) in skeletal muscle. We show that DOR has a direct impact on skeletal muscle mass in vivo. Thus, using different transgenic mouse models, we demonstrate that while muscle-specific DOR gain-of-function results in reduced muscle mass, loss-of-function causes muscle hypertrophy. DOR has been described as a protein with two different functions, i.e., a nuclear coactivator and an autophagy regulator (Baumgartner et. al., PLoS One, 2007; Francis et. al., Curr Biol, 2010; Mauvezin et. al., EMBO Rep, 2010; Nowak et. al., Mol Biol Cell, 2009). This is why we decided to analyze which of these two functions could explain the phenotype observed in our mice models. In this regard, we performed a transcriptomic analysis using microarrays looking for genes differentially expressed in the quadriceps muscle of WT and SKM-Tg mice as well as in C and SKM-KO animals. Surprisingly, only a reduced number of genes were dysregulated upon DOR manipulation and most of the genes underwent mild changes in expression. These data strongly suggest that DOR does not operate as a nuclear co-factor in mouse skeletal muscle under the conditions subjected to study. In contrast, DOR enhances basal autophagy in skeletal muscle and promotes muscle wasting when autophagy is a contributor to muscle loss. To determine the functional role of DOR in skeletal muscle, we generated transgenic mice (SKM-Tg) overexpressing DOR specifically in skeletal muscle under the Myosin-Light Chain 1 promoter/enhancer. The open reading frame of DOR was introduced in an EcoRI site in the MDAF2 vector, which contains a 1.5 kb fragment of the MLC1 promoter and 0.9 kb fragment of the MLC1/3 gene containing a 3' muscle enhancer element (Rosenthal et. al., PNAS, 1989; Otaegui et. al., FASEB J, 2003). The fragment obtained after the digestion of this construct with BssHII was the one used to generate both transgenic mouse lines. Nontransgenic littermates were used as controls for the transgenic animals (Wt). In addition, a muscle-specific DOR knock-out mouse line (SKM-KO) was also generated by crossing homozygous DOR loxP/loxP mice with a mouse strain expressing Cre recombinase under the control of the Myosin-Light Chain 1 promoter (Bothe et. al., Genesis, 2000). Deletion of exons 3 and 4 driven by Cre recombinase caused the ablation of DOR expression. Non-expressing Cre DOR loxP/loxP littermates were used as controls for knockout animals (C). Four-month-old male mice were used in all experiments. Mice were in a C57BL/6J pure genetic background. We used microarrays to analyze the effect of DOR gain-of-function and DOR ablation on skeletal muscle gene expression Total RNA from quadriceps muscles from 4-month-old male mice was extracted and used for hibridization on Affimetrix microarrays