[S100 calcium binding protein A16 promotes fat synthesis through endoplasmic reticulum stress in HepG2 cells].

The aim of this study was to investigate the role of S100 calcium binding protein A16 (S100A16) in lipid metabolism in hepatocytes and its possible biological mechanism. HepG2 cells (human hepatoma cell line) were cultured with fatty acid to establish fatty acid culture model. The control model was cultured without fatty acid. Each model was divided into three groups and transfected with S100a16 over-expression, shRNA and vector plasmids, respectively. The concentration of triglyceride (TG) in the cells was measured by kit, and the lipid droplets was observed by oil red O staining. Immunoprecipitation and mass spectrometry were used to find the interesting proteins interacting with S100A16, and the interaction was verified by immunoprecipitation. The further mechanism was studied by Western blot and qRT-PCR. The results showed that the intracellular lipid droplet and TG concentrations in the fatty acid culture model were significantly higher than those in the control model. The accumulation of intracellular fat in the S100a16 over-expression group was significantly higher than that in the vector plasmid transfection group. There was an interaction between heat shock protein A5 (HSPA5) and S100A16. Over-expression of S100A16 up-regulated protein expression levels of HSPA5, inositol-requiring enzyme 1α (IRE1α) and pIREα1, which belong to endoplasmic reticulum stress HSPA5/IRE1α-XBP1 pathway. Meanwhile, over-expression of S100A16 up-regulated the mRNA expression levels of adipose synthesis-related gene Srebp1c, Acc and Fas. In the S100a16 shRNA plasmid transfection group, the above-mentioned protein and mRNA levels were lower than those of vector plasmid transfection group. These results suggest that S100A16 may promote lipid synthesis in HepG2 cells through endoplasmic reticulum stress HSPA5/IRE1α-XBP1 pathway.

[Study and clinical application of auto-compressive and anti-rotate intramedullary nail].

OBJECTIVE: To design an auto-compressive and anti-rotate intramedullary nail (ACACIN) and to evaluate the preliminary clinical efficacy on fixing adult femur fracture. METHODS: From January 1998 to June 2001, 23 patients with femur fracture were stabilized with auto-compressive and anti-rotate intramedullary nail. 2-4 elastic blocks were installed into the proximal and distal different distance of quincunx nail to defend rotate and axis compress. RESULTS: Fracture healing were obtained in all 23 patients treated with auto-compressive and anti-rotate intramedullary nail, the time of fracture healing was 6-13 weeks in 21 cases and 15-22 weeks in 2 cases of old fracture. There was no complication related to infection, nail break, abnormal union and joint ankylosis. The results were excellent in 19 cases, good in 3 cases, and moderate in 1 case according Kolmert's criterion for function; the effective rate was 95.7%. CONCLUSION: Auto-compressive and anti-rotate intramedullary nail has a suitable radian for adult femur, can afford stable fixation, anti-rotate and axis compress.