Project description:microRNAs responsible for skeletal muscle atrophy are largely unclear. We used microarrays to examine microRNA profiles in rat gastrocnemius muscle of 5 days after denervation of sciatic nerve versus sham control.
Project description:To compare the microRNAs (miRNAs) expression profile in the innervated soleus muscle and L4-L6 DRG neuronsafter sciatic nerve entrapment with a non-constrictive silastic tube, subsequent surgical decompression, and denervation injury. The experimental soleus muscles and dorsal root ganglions (DRGs) from each experimental group (sham control, denervation, entrapment, and decompression) were analyzed with an Agilent® rat miRNA array to detect dysregulated miRNAs
Project description:Analysis of denervation induced regulation of muscle mass at gene expression level. The hypothesis tested in the present study was that the presence of MuRF1 contributes to the extent of gene expression changes observed in specific sets of genes during a challenge leading to muscle atrophy. Results provide important information on the response of triceps surae muscle to sciatic nerve resection (denervation), such as specific structural, metabolic, and neuromuscular junction associated genes, that may be influenced by MuRF1 during atrophy. Total RNA obtained from isolated triceps surae muscle subjected to 3 or 14 days post-denervation compared to nonsurgically treated littermate control muscles.
Project description:Carcinoma VCaP tumors that evolve in denervated rat prostate glands exhibited a significantly altered gene expression profile and phenotype as compared with VCaP tumors that evolve in the normal, innervated rat prostate gland. Interestingly, unilateral denervation resulted in a reduction in tumor size relative to control and the reduction was more pronounced with botox (chemical denervation) as compared with MPG excision (physical denervation). Chemical and Physical denervation yield similar gene expression profiles.
Project description:To compare the microRNAs (miRNAs) expression profile in the innervated soleus muscle and L4-L6 DRG neuronsafter sciatic nerve entrapment with a non-constrictive silastic tube, subsequent surgical decompression, and denervation injury. The experimental soleus muscles and dorsal root ganglions (DRGs) from each experimental group (sham control, denervation, entrapment, and decompression) were analyzed with an Agilent® rat miRNA array to detect dysregulated miRNAs Three-condition experiment, DRGs and soleus muscles of the rats receiving sciatic nerve denervation 6 months, sciatic nerve entrapment 6 months, and sciatic nerve entrapment 6 months then decompression for 3 months v.s. soleus muscle (sham control), Biological replicates: 1 control replicates, 3 experiment replicates
Project description:Analysis of denervation induced regulation of muscle mass at gene expression level. The hypothesis tested in the present study was that the presence of MuRF1 contributes to the extent of gene expression changes observed in specific sets of genes during a challenge leading to muscle atrophy. Results provide important information on the response of triceps surae muscle to sciatic nerve resection (denervation), such as specific structural, metabolic, and neuromuscular junction associated genes, that may be influenced by MuRF1 during atrophy.
Project description:Background: Skeletal muscle function crucially depends on motor innervation and after injury on the resident muscle stem cells (MuSCs). However, it is poorly understood how innervation affects MuSC properties. Methods: We investigated the alterations of MuSCs and their immediate niche, the myofiber, after denervation in a surgery-based mouse model of unilateral sciatic nerve transection. FACS-isolated MuSCs were subjected to transcriptomics and proteomics analyses to investigate which changes occur after denervation. We performed Cardiotoxin-induced muscle injury, MuSC transplantation and floating myofiber cultures to assess MuSC functionality after denervation in addition to bioinformatics and histological analyses. Results: We observed a significant increase in the number of MuSCs (Pax7 positive; p-value= 0.0441), proliferating MuSCs (Pax7/Ki67 positive; p-value= 0.0023), activated MuSCs (MyoD positive; p-value= 0.0016) and differentiating MuSCs (Myog positive; p-value= 0.0057) after denervation. This aberrant activation and premature commitment of MuSCs to the myogenic lineage was accompanied by profound alterations on the mRNA (2613 differentially expressed genes, adj. p-value <0.05) and protein (1096 differentially abundant proteins, q-value <0.05) level after denervation. MuSCs from denervated hosts still engrafted and fused to form new myofibers irrespective of the innervation status of the recipient, suggesting the MuSC niche is driving alterations in MuSCs after denervation. The myofiber transcriptome after denervation showed massive changes in the general expression profile (10492 DEGs, p-value <0.05) and in several predicted secreted factors. Incubation of myofiber-associated MuSCs with supernatant from denervated myofibers increased cluster formation, reinforcing myofibers as a source of secreted factors driving MuSC alterations after denervation. Opn and Tgfb1 showed an increased secretion by denervated myofibers (30-fold and 6000-fold, respectively), and incubation with Tgfb1 alone induced Junb expression in myogenic cells, one of the genes highly upregulated in MuSCs after denervation (p-value= 1.85e-18, log2fc= 3.27), demonstrating that myofiber-secreted ligands influence MuSC gene expression. A combination of skeletal muscle injury and denervation led to reduced numbers of proliferating MuSCs (Sham: 47 vs DEN: 19.75 cells per cross section 10 days post-injury) and sustained high levels of developmental myosin heavy chain (Sham: 1 % vs DEN: 40 % of all myofibers 21 days post-injury), indicating hampered MuSC functionality due to changes in the microenvironment. Conclusion: Denervation of skeletal muscle causes alterations in myofiber secretion, leading to activation and profound changes of MuSCs, ultimately resulting in a reduced regenerative capacity. As these alterations are partially reversible, MuSCs are a promising target for novel treatment options for neuromuscular disorders and peripheral nerve injuries.
Project description:Muscle denervation causes skeletal muscle atrophy. The goal of these studies was to determine the effects of denervation on skeletal muscle mRNA levels in C57BL/6 mice. For additional details see Ebert et al, Stress-Induced Skeletal Muscle Gadd45a Expression Reprograms Myonuclei and Causes Muscle Atrophy. JBC epub. June 12, 2012.
Project description:Background: Skeletal muscle function crucially depends on motor innervation and after injury on the resident muscle stem cells (MuSCs). However, it is poorly understood how innervation affects MuSC properties. Methods: We investigated the alterations of MuSCs and their immediate niche, the myofiber, after denervation in a surgery-based mouse model of unilateral sciatic nerve transection. FACS-isolated MuSCs were subjected to transcriptomics and proteomics analyses to investigate which changes occur after denervation. We performed Cardiotoxin-induced muscle injury, MuSC transplantation and floating myofiber cultures to assess MuSC functionality after denervation in addition to bioinformatics and histological analyses. Results: We observed a significant increase in the number of MuSCs (Pax7 positive; p-value= 0.0441), proliferating MuSCs (Pax7/Ki67 positive; p-value= 0.0023), activated MuSCs (MyoD positive; p-value= 0.0016) and differentiating MuSCs (Myog positive; p-value= 0.0057) after denervation. This aberrant activation and premature commitment of MuSCs to the myogenic lineage was accompanied by profound alterations on the mRNA (2613 differentially expressed genes, adj. p-value <0.05) and protein (1096 differentially abundant proteins, q-value <0.05) level after denervation. MuSCs from denervated hosts still engrafted and fused to form new myofibers irrespective of the innervation status of the recipient, suggesting the MuSC niche is driving alterations in MuSCs after denervation. The myofiber transcriptome after denervation showed massive changes in the general expression profile (10492 DEGs, p-value <0.05) and in several predicted secreted factors. Incubation of myofiber-associated MuSCs with supernatant from denervated myofibers increased cluster formation, reinforcing myofibers as a source of secreted factors driving MuSC alterations after denervation. Opn and Tgfb1 showed an increased secretion by denervated myofibers (30-fold and 6000-fold, respectively), and incubation with Tgfb1 alone induced Junb expression in myogenic cells, one of the genes highly upregulated in MuSCs after denervation (p-value= 1.85e-18, log2fc= 3.27), demonstrating that myofiber-secreted ligands influence MuSC gene expression. A combination of skeletal muscle injury and denervation led to reduced numbers of proliferating MuSCs (Sham: 47 vs DEN: 19.75 cells per cross section 10 days post-injury) and sustained high levels of developmental myosin heavy chain (Sham: 1 % vs DEN: 40 % of all myofibers 21 days post-injury), indicating hampered MuSC functionality due to changes in the microenvironment. Conclusion: Denervation of skeletal muscle causes alterations in myofiber secretion, leading to activation and profound changes of MuSCs, ultimately resulting in a reduced regenerative capacity. As these alterations are partially reversible, MuSCs are a promising target for novel treatment options for neuromuscular disorders and peripheral nerve injuries.
Project description:Muscle denervation causes skeletal muscle atrophy. The goal of these studies was to determine the effects of denervation on skeletal muscle mRNA levels in C57BL/6 mice. For additional details see Ebert et al, Stress-Induced Skeletal Muscle Gadd45a Expression Reprograms Myonuclei and Causes Muscle Atrophy. JBC epub. June 12, 2012. Left sciatic nerves of C57BL/6 mice were transected. Seven days later bilateral tibialis anterior muscles were harvested. mRNA levels in denervated muscles were normalized to levels in contralateral innervated muscles.