Project description:ADAMTSL2 mutations cause geleophysic dysplasia, which is characterized by short stature, pseudomuscular build, joint stiffness and tight skin. To elucidate the role of ADAMTSL2 in skeletal muscle myogenesis, we used C2C12 myoblasts, which differentiate and form myotubes when serum is reduced as a model system for myogenesis. Adamtsl2 was depleted by stably expressing shRNA targeting Adamtsl2 mRNA. Upon shRNA-mediated depletion of Adamtsl2, C2C12 myoblasts did not differentiate and did not form myosin heavy chain-positive myotubes in cell culture.
Project description:Progenitor cells require coordinated expression of lineage-specific genes to regulate differentiation into daughter cell types. Hopx labels cardiac progenitors that are commited to the cardiac myocyte lineage. Hopx-deficiency leads to thin myocardium in approximately mid-gestation lethality in approximately 50% of embryos (secondary to thin myocardium and presumed cardiac rupture). Hopx-/- EBs display impaired myogenesis during cardiac differentiation. ChIP-seq and RNA expression analysis suggests that Hopx down regulates Wnt signaling by directly occupying and repressing wnt ligand genes. Analysis of embryoid bodies on day 8 of cardiac differentiation. RNA was made of from Hopx +/- embryoid bodies or Hopx -/- embryoid bodies treated with 12.5 uM XAV939. Heterozygous embryoid bodies included 0 uM XAV939, a well-characterized, known Wnt inhibitor. Embryonic stem cell lines were derived from littermate mouse blastocysts. Results provide insight into gene programs regulated by Hopx in cardiac development.
Project description:Metabolic stress and changes in nutrient levels modulate many aspects of skeletal muscle function during aging and disease. Growth factors and cytokines secreted by skeletal muscle, known as myokines, are important signaling factors but it is largely unknown whether they modulate muscle growth and differentiation in response to nutrients. Here, we find that changes in glucose levels increase the activity of the glucose-responsive transcription factor MLX, which promotes and is necessary for myoblast fusion. MLX promotes myogenesis not via an adjustment of glucose metabolism but rather by inducing the expression of several myokines, including insulin like-growth factor-2 (IGF2), whereas RNAi and dominant-negative MLX reduce IGF2 expression and block myogenesis. This phenotype is rescued by conditioned media from control muscle cells and by recombinant IGF2, which activates the myogenic kinase Akt. Importantly, MLX null mice display decreased IGF2 induction and diminished muscle regeneration in response to injury, indicating that the myogenic function of MLX is conserved in vivo. Thus, glucose is a signaling molecule that regulates myogenesis and muscle regeneration via MLX/IGF2/Akt signaling.â??The data pproided are histome H4 acetlation data for MLX DN and MLX wt samples; 3 MLX DN H4 Ac Chip seq samples , 3 Inputs, 3 MLX WT H4 Ac samples and 3 WT inputs
Project description:Modulating the number of muscle stems cells, called satellite cells, during early postnatal development produces long-term effects on muscle growth. We tested the hypothesis that high expression levels of the anti-aging protein Klotho in early postnatal myogenesis increase satellite cell numbers by influencing the epigenetic regulation of genes that regulate myogenesis. Our findings show that elevated klotho expression caused a transient increase in satellite cell numbers and slowed muscle fiber growth, followed by a period of accelerated muscle growth that resulted in larger fibers. Klotho also transcriptionally down-regulated the H3K27 demethylase Jmjd3, increased H3K27 methylation and decreased expression of genes in the canonical Wnt pathway, which was associated with a significant delay in muscle differentiation. In addition, Klotho stimulation and subsequent Jmjd3 down-regulation produced similar but not additive reductions in the expression of Wnt4, Wnt9a and Wnt10a in myogenic cells, indicating that inhibition occurred through a common pathway. Together, our results identify a novel pathway through which Klotho influences myogenesis by reducing expression of Jmjd3, leading to reductions in the expression of Wnt genes and inhibition of canonical Wnt signaling.
Project description:Canonical Wnt signaling is crucial for vascularization of the central nervous system and blood-brain barrier (BBB) formation. BBB formation and modulation are not only important for development, but also relevant for vascular and neurodegenerative diseases. However, beyond the early requirement of Wnt signaling for brain capillary development, there is little understanding of how Wnt signaling further contributes to brain angiogenesis and BBB formation. By combining high resolution in vivo imaging with temporally and spatially controlled manipulation of Wnt signaling, we were able to dissect different requirements for Wnt signaling during brain angiogenesis and BBB formation. In the absence of Wnt signaling, premature Sphingosine-1-phosphate receptor (S1pr) signaling leads to a reduction of VE-cadherin and Esama at cell-cell junctions. Wnt signaling most likely suppresses S1pr signaling during angiogenesis to enable the dynamic junction formation during anastomosis, whereas later S1pr signaling regulates BBB maturation and VE-cadherin stabilization. Our data provides a novel link between brain capillary angiogenesis and BBB formation and identifies Wnt signaling as coordinator of the timing and as regulator of anastomosis.
Project description:Metabolic stress and changes in nutrient levels modulate many aspects of skeletal muscle function during aging and disease. Growth factors and cytokines secreted by skeletal muscle, known as myokines, are important signaling factors but it is largely unknown whether they modulate muscle growth and differentiation in response to nutrients. Here, we find that changes in glucose levels increase the activity of the glucose-responsive transcription factor MLX, which promotes and is necessary for myoblast fusion. MLX promotes myogenesis not via an adjustment of glucose metabolism but rather by inducing the expression of several myokines, including insulin like-growth factor-2 (IGF2), whereas RNAi and dominant-negative MLX reduce IGF2 expression and block myogenesis. This phenotype is rescued by conditioned media from control muscle cells and by recombinant IGF2, which activates the myogenic kinase Akt. Importantly, MLX null mice display decreased IGF2 induction and diminished muscle regeneration in response to injury, indicating that the myogenic function of MLX is conserved in vivo. Thus, glucose is a signaling molecule that regulates myogenesis and muscle regeneration via MLX/IGF2/Akt signaling. The data pproided are histome H4 acetlation data for MLX DN and MLX wt samples;
Project description:Neurons and oligodendrocytes communicate to regulate oligodendrocyte development and ensure appropriate axonal myelination. Here, we show that Glycerophosphodiester phosphodiesterase 2 (GDE2) encodes a neuronal pathway that promotes oligodendrocyte maturation through the release of soluble neuronally-derived factors. Mice lacking global or neuronal GDE2 expression have reduced mature oligodendrocytes and myelin proteins but retain normal numbers of oligodendrocyte precursor cells (OPCs). WT OPCs cultured in conditioned medium (CM) from Gde2 null (Gde2KO) neurons exhibit delayed maturation, recapitulating in vivo phenotypes. Gde2KO neurons show robust reduction in canonical Wnt signaling and genetic activation of Wnt signaling in Gde2KO neurons rescues in vivo and in vitro oligodendrocyte maturation. Phosphacan, a known stimulant of OL maturation, is reduced in CM from Gde2KOneurons but is restored when Wnt signaling is activated. These studies identify GDE2 control of Wnt signaling as a neuronal pathway that signals to oligodendroglia to promote oligodendrocyte maturation.