[Effect of knockdown of O-Glcnac transferase on hepatocyte fat synthesis]

Objective: To investigate the effect of knockdown of O-GlcNAc transferase (OGT) on hepatocyte fat synthesis. Methods: Liver cell line L02 were used to established the model of hepatic steatosis. The levels of OGT and O-GlcNAc protein were detected by Western blot. The OGT knockdown cell line of L02 cells was established, and its lipid formation ability was detected after induction of oleic acid (OA). Real-time quantitative PCR (qRT-PCR) and Western blot were used to detect mRNA and protein expression of enzymes related to fat synthesis. An independent sample t test was used. Results: Western blot showed that the expression of OGT and O-GlcNAc was increased in L02 cells after adipogenesis (P < 0.05). After shOGT lentivirus infects L02 cells, OGT mRNA levels were down-regulated (P < 0.01). Oil red O staining showed that the lipid in L02 shOGT cells decreased, qRT-PCR showed that the mRNA expressions of fat synthase (ACC1), (FASN) and (SCD1) were decreased, the difference was statistically significant (P < 0.05), protein Expression is consistent with mRNA expression. Conclusion: Knockdown of OGT can inhibit hepatocyte fat synthesis by reducing O-GlcNAc levels.

Expression of TNF-α, VEGF, and MMP-3 mRNAs in synovial tissues and their roles in fibroblast-mediated osteogenesis in ankylosing spondylitis

The aim of this study was to explore the mRNA levels of tumor necrosis factor-α (TNF-α), vessel endothelial growth factor (VEGF), and matrix metalloproteinase-3 (MMP-3) in synovial tissues in ankylosing spondylitis (AS), and to analyze the functions of these proteins in the differentiation of AS synovial tissue fibroblasts into osteoblasts (OB) and osteoclasts. Synovial tissue samples from 22 AS patients and 22 normal individuals were collected. In situ hybridization was utilized to detect TNF-α, VEGF, and MMP-3 transcripts. After counting numbers of positive cells, Spearman analysis was used to determine the correlation between transcriptional levels of the three mRNAs and the AS disease activity index (BASDAI) and the C-response protein (CRP) levels. With the addition of TNF-α, VEGF, or both factors into cultured normal synovial fibroblasts, osteocalcin (bone gla protein, BGP) secretion levels were compared. We found that expression of TNF-α, VEGF, and MMP-3 was identified exclusively in the disease group. mRNA levels were significantly positively correlated with BASDAI (r = 0.42, 0.38, and 0.47, respectively; P < 0.05) and CRP (r = 0.44, 0.34, and 0.47 respectively; P < 0.05) scores. The secretion level of BGP in normal synovial fibroblasts increased progressively with increasing concentrations of VEGF or TNF-α (P < 0.01 compared to levels before treatment). Furthermore, co-incubation using both VEGF and TNF-α significantly elevated BGP levels compared to the single addition of VEGF or TNF-α (P < 0.01). These results suggest TNF-α, VEGF, and MMP-3 might directly participate in the differentiation of fibroblasts into OBs.

Errors in the identification of the transepicondylar and anteroposterior axes of the distal femur in total knee replacement using minimally-invasive and conventional approaches

We have investigated the errors in the identification of the transepicondylar axis and the anteroposterior axis between a minimally-invasive and a conventional approach in four fresh-frozen cadaver knees. The errors in aligning the femoral prosthesis were compared with the reference transepicondylar axis as established by CT.

The error in the identification of the transepicondylar axis was significantly higher in the minimal approach (4.5° of internal rotation, sd 4) than in the conventional approach (3° of internal rotation, sd 4; p < 0.001). The errors in identifying the anteroposterior axis in the two approaches were 0° (sd 5) and 1.8° (sd 5) of internal rotation, respectively (p < 0.001).

Synthesis and biological activity of L-tyrosine-based PPARgamma agonists with reduced molecular weight

A series of PPARgamma agonists were synthesized from L-tyrosine that incorporated low molecular weight N-substituents. The most potent analogue, pyrrole (4e), demonstrated a K(i) of 6.9nM and an EC(50) of 4.7nM in PPARgamma binding and functional assays, respectively. Pyrrole (4e), which is readily synthesized from L-tyrosine methyl ester in four steps, also demonstrated in vivo activity in a rodent model of Type 2 diabetes.

Identification of a series of PPAR gamma/delta dual agonists via solid-phase parallel synthesis

We have developed a general solid-phase synthesis for identification of PPAR ligands. Synthesis of a 480-member library led to the identification of a potent PPAR gamma/delta dual agonist 23. Compound 23 showed good plasma exposure in rats and demonstrated antihyperglycemic and antihyperlipidemic efficacy in diabetic fatty Zucker rats.

Identification of a series of oxadiazole-substituted alpha-isopropoxy phenylpropanoic acids with activity on PPARalpha, PPARgamma, and PPARdelta

A series of oxadiazole-substituted alpha-isopropoxy phenylpropanoic acids with dual agonist activity on PPARalpha and PPARgamma is described. Several of these compounds also showed partial agonist activity on PPARdelta. Resolution of one analogue showed that PPARalpha and PPARgamma activity resided in mainly one enantiomer, whereas PPARdelta activity was retained in both enantiomers.