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:microRNAs control cardiac remodeling post myocardial infarction, though the cellular and molecular mechanisms remain unclear. We used microarrays to examine microRNA profiles in mice hearts 21 days after ligation of left anterior descending coronary artery (LAD) versus sham control.
Project description:Background: Skeletal muscle crucially depends on motor innervation, and, when damaged, on the resident muscle stem cells (MuSCs). However, the role and function of MuSCs in the context of denervation remains poorly understood. Methods: Alterations of MuSCs and their myofiber niche after denervation were investigated in a surgery-based mouse model of unilateral sciatic nerve transection. FACS-isolated MuSCs were subjected to RNA-sequencing and mass spectrometry for the analysis of intrinsic changes after denervation and in vivo assays, such as Cardiotoxin-induced muscle injury or MuSC transplantation, were performed to assess MuSC functions after denervation. Bioinformatic and histological analyses were conducted to further examine MuSCs and their myofiber niche after denervation. Results: Muscle cross section analysis revealed a significant increase in Pax7 (p-value= 0.0441), Pax7/Ki67 (p-value= 0.0023), MyoD (p-value= 0.0016) and Myog (p-value= 0.0057) positive cells after denervation, illustrating a break of quiescence and commitment to the myogenic lineage. An Omics approach showed profound intrinsic alterations on the mRNA (2613 differentially expressed genes, p-value <0.05) and protein (1096 differentially abundant proteins, q-value <0.05) level of MuSCs 21 days after denervation. Skeletal muscle injury together with denervation surgery caused deregulated regeneration, indicated by the reduced number of proliferating MuSCs and sustained high levels of developmental myosin heavy chain (Sham: 1 % vs DEN: 40 % of all myofibers), at 21 days post-surgery. In a transplantation assay, MuSCs from a denervated host were still able to engraft and fuse to form new myofibers, irrespective of the innervation status of the recipient muscle. Analysis of myofibers revealed not only massive changes in the expression profile (10492 differentially expressed genes, p-value <0.05) after denervation, but it was also shown that secretion of Opn and Tgfb1 from denervated myofibers was increased 30-fold and 6000-fold, respectively. Bioinformatic analyses indicated strong upregulation of gene expression of the transcription factor Junb in MuSCs from denervated muscles (log2 fold change = 3.27). Of interest, Tgfb1 recombinant protein was able to induce Junb gene expression in vitro, demonstrating that myofiber-secreted ligands can induce gene expression changes in MuSCs, which might result in the phenotypes observed after denervation. Conclusion: Skeletal muscle denervation is altering myofiber secretion, causing MuSC activation and profound intrinsic changes, leading to reduced regenerative capacity. As MuSCs possess a remarkable regenerative potential, they might represent a promising target for novel treatment options for neuromuscular disorders and peripheral nerve injuries.
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: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:We investigated calcaneal tendon extracellular matrix (ECM) remodeling after gastrocnemius muscle injury using a rat model. Wistar rats were randomly divided into four groups: control group (C; animals that were not exposed to muscle injury) and harvested at different time points post gastrocnemius muscle injury (3, 14 and 28 days) for gene expression analysis. qRT-PCR was performed using TaqMan Universal PCR Master Mix system (Applied Biosystems, CA, USA - Cat. 4304437).
Project description:We showed that nandrolone attenuated subacute, but not acute, denervation atrophy and upregulation of MAFbx. The present study explored the molecular determinants for this time-dependent effect using microarray analysis to identify genes that were differentially regulated by administration of nandrolone for 7 days beginning either concomitantly with denervation (7 days) or 29 days later (35 days) Experiment Overall Design: The analysis used gastrocnemius muscle from male Wistar-Hannover rats that had undergone left sciatic nerve transaction followed by the administration of nandrolone or vehicle beginning either on the day of surgery or 29 days thereafter. Animals had been sacrificed 7 days after starting nandrolone (Nan) or vehicle (Veh) (e.g, at days 7 or 35).