BACKGROUND: Under indirect co-culture conditions, chondrocytes can induce bone marrow mesenchymal stem cells to differentiate into chondrocytes. Osteocytes are the seed cells of chondrocytes, but co-culture of osteocytes with chondrocytes is rarely reported. OBJECTIVE: To induce the chondrogenic differentiation of periosteum-derived cells (PDCs) by indirect co-culture with chondrocytes. METHODS: Chondrocytes were isolated from the rabbits by trypsin and collagenase Ⅱ digestion. Rabbit PDCs were obtained by the explants culture method. Passage 2 chondrocytes and PDCs underwent indirect co-culture at 1:1 in Transwell system as experimental group. PDCs cultured alone were as control group. After 2 weeks of culture, the cellular morphological changes were observed by inverted contrast phase microscope. The expression levels of collagen type Ⅱ and proteoglycan were detected by collagen type Ⅱ immunohistochemistry and toluidine blue staining. The mRNA expression levels of proteoglycan, collagen type Ⅱ and SRY-related protein-9 were detected by RT-PCR. RESULTS AND CONCLUSION: After 2 weeks of culture, PDCs in the experimental group were gradually transformed to chondrocyte-like cells, while PDCs in the control group still remained long spindle-shaped. Collagen type Ⅱ immunohistochemistry staining and toluidine blue staining were positive in the experimental group, while the results were negative in the control group. Additionally, RT-PCR results indicated that the relative mRNA expression levels of proteoglycan, collagen type Ⅱ and SRY-related protein-9 in the experimental group were significantly higher than those in the control group. Therefore, chondrocytes can induce PDCs to differentiate into chondrocytes under indirect co-culture conditions.

BACKGROUNDPeroxisome proliferator-activated receptor-gamma (PPARgamma) is a kind of ligand-activated transcription factors binding to peroxisome proliferator response element (PPRE), a specific recognition site. It is thought to play a critical role in glucose and lipid metabolism and in inflammation control. The aim of this study was to establish a new cellular model for the quick screening of lipid-lowering drugs, which may be effective as PPAR-gamma ligands on the PPRE-mediated pathway regulatory system.

METHODSTwo plasmids were constructed: pXOE-PPARgamma, in which the human PPARgamma gene was in the downstream of TFIIIA gene promoter, and pLXRN-PPRE-d2EGFP, in which the enhanced green fluorescent protein (EGFP) gene was subcloned into PPRE. The xenopus oocytes were injected with these two plasmids, and consequently treated with prostaglandin E1, pioglitazone, and different kinds of lipid-lowering drugs. After 3 days, the oocytes were observed under a fluorescence microscope. To confirm the drug action,we injected pXOE-PPARgamma plasmid into the oocytes, which then treated with prostaglandin E1 and Hawthorn flavonoids. The mass of expressed lipoprotein lipase (LPL) in the cells was determined by enzyme labeling linked immunosorbent assay (ELISA).

RESULTSThe expression of EGFP was only induced by prostagalandin E1, pioglitazone, Hawthorn flavonoids. A concentration-response relationship was seen between expressed EGFP and Hawthorn flavonoids. The levels of LPL in both Hawthorn flavonoids groups and PPARgamma ligand prostagalandin E1 group injected with pXOE-PPARgamma plasmid increased significantly (< 0.001) compared with controls, and a concentration-response relationship was observed between LPL mass and Hawthorn flavonoids.

CONCLUSIONSIt is possible to establish a PPRE regulatory EGFP reporter system in xenopus oocytes to monitor the activity of PPARgamma ligand. Hawthorn flavonoids can increase the expression of gene downsteam of PPRE by effect on the PPRE pathway regulatory system.

Alprostadil ; pharmacology ; Animals ; Crataegus ; Female ; Hypolipidemic Agents ; pharmacology ; Lipoprotein Lipase ; biosynthesis ; Medicine, Chinese Traditional ; Oocytes ; metabolism ; PPAR gamma ; physiology ; Peroxisome Proliferators ; pharmacology ; Plasmids ; Response Elements ; physiology ; Xenopus

With PVA as the carrier, the frozen beer yeast cells were immobilized for production of CTP from CMP. we explored the optimal condition of the immobilization from the aspects of the type, concentration of the PVA, and the immobilizing methods of cells In all 8 continuous batch of fermentation under the reactional condition of the immobilized cells, the conversion rate of CTP were maintained about 85% - 95%. Moreever, the storage stability of immobilized cells were investigated, and the products was also isolated and identifided by HPLC.
Beer ; microbiology ; Bioreactors ; microbiology ; Cells, Immobilized ; cytology ; metabolism ; Chromatography, High Pressure Liquid ; Cytidine Monophosphate ; metabolism ; Cytidine Triphosphate ; metabolism ; Fermentation ; Industrial Microbiology ; methods ; Polyvinyl Alcohol ; Saccharomyces cerevisiae ; cytology ; metabolism

OBJECTIVETo investigate the molecular mechanisms and effective target points of lipid-lowering drug, Rhizoma Curcumae Longae, and study the effect of curcumin on the expression of low density lipoprotein (LDL) receptors in macrophages in mice.

METHODSMacrophages in mice were treated with curcumin, which was purified from the ethanolly extraction of Rhizoma Curcumae Longae for 24 h. The LDL receptors expressed in the macrophages were determined by enzyme-linked immunosorbent assay (ELISA) and assay of DiI labeled LDL uptake by flow cytometer.

RESULTSIt was found for the first time that 10 micromol/L-50 micromol/L curcumin could obviously up-regulate the expression of LDL receptor in macrophages in mice, and a dose-effect relationship was demonstrated.

CONCLUSIONOne of the lipid-lowering mechanisms of traditional Chinese medicine, Rhizoma Curcumae Longae, was completed by the effect of curcumin through the up-regulation of the expression of LDL receptor.

Animals ; Cell Line ; Curcumin ; pharmacology ; Gene Expression ; drug effects ; Hypolipidemic Agents ; pharmacology ; Macrophages ; drug effects ; Mice ; Receptors, LDL ; drug effects ; genetics ; Up-Regulation ; drug effects ; genetics