Anti-FOS polyclonal antibody

Objectives: Postmenopausal osteoporosis (PMO) is a prevalent metabolic bone disease with high morbidity and serious complications. Here, we studied the effect of glycyrrhizin on bone metabolism using the ovariectomized (OVX) mouse model. Methods: Osteoclast-related gene expression and osteoclastic function were evaluated in RAW264.7 cells and bone marrow-derived monocytes (BMMs) by real-time polymerase chain reaction and bone resorption assay. For animal studies, female C57BL/6J mice were randomly divided into sham operated, OVX and OVX with glycyrrhizin groups. Bone mass and trabecular microarchitecture were analyzed by micro-computed tomography, dual X-ray absorptiometry, and histomorphometric analysis. Receptor activator of nuclear factor-kappa B (NF-kappa B) ligand-induced osteoclastogenesis and the NF-kappa B signaling pathway were studied by tartrate-resistant acid phosphatase staining and western blotting, respectively. Results: Glycyrrhizin inhibits RANKL-induced expression ofNfatc-1,c-Fos,Trap,Ds-stamp, andCtskin RAW264.7 cells. Also, fewer bone resorption pits form when BMMs are incubated in the presence of glycyrrhizin. Glycyrrhizin ameliorates bone loss and improves trabecular bone parameters in OVX mice. BMMs isolated from OVX mice show higher ability of RANKL-induced osteoclastogenesis, which is tremendously reversed by glycyrrhizin. There is significantly higher phosphorylation of I kappa B-alpha at Ser32 and NF-kappa B p65 at Ser536, as well as increased protein levels of c-FOS and NFATc-1 in BMMs of OVX mice, which are all greatly suppressed by glycyrrhizin. Conclusions: Our findings imply that glycyrrhizin is a potential efficient adjuvant therapeutic for PMO.

Megakaryoblastic leukemia 2 (MKL2)/myocardin-related transcription factor-B (MRTFB), a serum response factor (SRF) coactivator, is an important regulator of gene expression and neuronal morphology. Here, we show that different mouse MRTFB splice isoforms, including a novel fourth MRTFB isoform named spliced neuronal long isoform of SRF transcriptional coactivator (SOLOIST)/MRTFB isoform 4 (MRTFB i4), play distinct roles in this process.SOLOIST/MRTFB i4has a short exon that encodes 21 amino acid residues ahead of the first RPXXXEL (RPEL) motif in MRTFB isoform 3. Quantitative PCR revealed thatSOLOIST/MRTFBi4 and isoform 1 were enriched in the forebrain and neurons, and up-regulated during brain development. Conversely, isoform 3 was detected in various tissues, including both neurons and astrocytes, and was down-regulated in the developing brain. Reporter assays supported the SRF-coactivator function of SOLOIST/MRTFB i4 as well as isoform 1. Acute expression of MRTFB isoform 1, but not isoform 3 or SOLOIST/MRTFB i4, in neuronal cells within 24 hr drastically increased endogenous immediate early gene [c-fos,egr1, and activity-regulated cytoskeleton-associated protein] expression, but not endogenousactinin alpha 1,beta-actin,gelsolin, orsrfgene expression measured by qPCR. Over-expression of SOLOIST/MRTFB i4 reduced the dendritic complexity of cortical neurons, whereas over-expression of isoform 1 increased this complexity. Co-expression of isoform 1 and SOLOIST/MRTFB i4 in cortical neurons revealed that isoform 1 competitively counteracted down-regulation by SOLOIST/MRTFB i4. Our findings indicate that MRTFB isoforms have unique expression patterns and differential effects on gene expression and dendritic complexity, which contribute to shaping neuronal circuits, at least in part.