Neuron-secreted factors promote the growth of skeletal muscle cells / 中国组织工程研究

BACKGROUND:There is no effective treatment for muscle atrophy caused by peripheral nerve damage. Skeletal muscle cel s, a structural unit of muscle contraction, can be used for studies on muscle atrophy when cultured in vitro. OBJECTIVE:To investigate the promotion effect of neuron-secreted factors on the growth of skeletal muscle cel s in vitro. METHODS:Skeletal muscle cel s primary cultured in vitro were divided into two groups:experimental group with neuron-secreted factors, and control group with common culture medium, respectively. Afterwards, the number of skeletal muscle cel s and expression level of alpha actin were detected by hematoxylin-eosin staining and immunohistochemical staining, respectively. RESULTS AND CONCLUSION:The number of skeletal muscle cel s and expression level of alpha actin in the experimental group were significantly higher than those in the control group (P<0.05). In conclusion, neuron-secreted factors have the ability of promoting the growth of skeletal muscle cel s and may be helpful for denervated muscle atrophy.

MicroRNA 144 negatively regulates Toll-like receptor 2 expression in rat macrophages / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the relationship between miR-144 and Toll-like receptor 2 (TLR2).</p><p><b>METHODS</b>RT-qPCR was used to determine the expression of TLR2 and its downstream inflammatory cytokine TNF-α in rat macrophage cell line NR8383 transfected by a mimic miR-144 or miR-144 inhibitor. The fragments of 3'UTR region of rat TLR2 mRNA including wild or mutant miR-144 binding site obtained by PCR using rat liver cDNA were ligated to pmirGLO report gene vector digested with SacI and XbaI to construct the recombinant vectors of pmir-TLR2-3'UTR and pmir-mutant-TLR2-3'UTR. The miR-144 targeting TLR2 was further determined by dual luciferase reporter assay and miR-144 mimics.</p><p><b>RESULTS</b>TLR2 and TNF-α in NR8383 cells were decreased after transfection with 100 nmol/L mimic miR-144 for 24 h and increased after transfection with 100 nmol/L miR-144 inhibitor. PCR and double-enzyme digestion with SacI and XbaI confirmed successful insertion of the target fragments. Dual luciferase reporter assay suggested the binding of miR-144 to the 3'UTR of rat TLR2 mRNA.</p><p><b>CONCLUSION</b>miR-144 negatively regulates the expression of TLR2 and its down-stream cytokine TNF-α by targeting TLR2 in NR8383 cells.</p>