ABSTRACT
The steadily increasing epidemic of obesity continues at alarming rates, is an important public health problem, and expression changes of S100A16 and 11 ß-hydroxysteroid dehydrogenase type 1(11ß-HSD1) is attributable to the adipocyte differentiation. In our previous study, we found that 11ß-HSD1 protein expression increased in S100A16-overexpressed 3T3-L1 cell model. In order to further investigate the relationship between S100A16 and 11ß-HSD1, and the molecular mechanisms of S100A16-induced adipogenesis, we constructed S100A16 transgenic and knockout mouse, and S100A16-overexpressed 3T3-L1 preadipocyte cell. Using S100A16 transgenic (S100A16Tg/+) mice fed with normal fat diet (NFD) and high fat diet (HFD) diet model, we evaluated the effect of S100A16 on adipogenesis, expression of 11ß-HSD1, and RNA sequencing and quantification of gene expression. Using the 3T3-L1 cell model, we examined the effect of S100A16 and 11ß-HSD1 on pre-adipocyte differentiation, and cell signaling events of 11ß-HSD1 overexpression induced by S100A16. We found that when compared with C57BL/6 mice, overexpression of S100A16 under the condition of HFD increased lipid content in WAT and fat infiltration in hepatocytes, 11ß-HSD1 protein expression increased along with S100A16. Elevated S100A16 and 11ß-HSD1 expression promoted adipogenesis in 3T3-L1 cells. Overexpression of S100A16 inhibited the degradation of 11ß-HSD1. We conclude that S100A16-induced adipogenesis is associated with up-regulation of 11ß-HSD1.
Subject(s)
11-beta-Hydroxysteroid Dehydrogenase Type 1/metabolism , Adipocytes/cytology , Adipogenesis/physiology , S100 Proteins/metabolism , Weight Gain/physiology , 3T3 Cells , Adipogenesis/genetics , Animals , Cell Line , Diet, High-Fat , Gene Expression Regulation/genetics , Hepatocytes/metabolism , Insulin Resistance/physiology , Lipid Droplets/metabolism , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Obesity/pathology , S100 Proteins/genetics , Transcriptional ActivationABSTRACT
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.
Subject(s)
Endoplasmic Reticulum Stress , Lipid Metabolism , S100 Proteins/physiology , Endoplasmic Reticulum Chaperone BiP , Endoribonucleases/physiology , Heat-Shock Proteins/physiology , Hep G2 Cells , Humans , Protein Serine-Threonine Kinases/physiology , Triglycerides/biosynthesis , X-Box Binding Protein 1/physiologyABSTRACT
AIM: To investigate the changes of large-conductance calcium-activated potassium channels (BKCa, MaxiK) during aging and relations between the changes and blood pressure. METHODS: Male spontaneously hypertensive rats (SHR) aged 9, 15, 21, 27, 33 weeks (the number of each weeks SHR was 4) were selected as hypertension group rats, corresponding gender, weeks and number Wistar-Kyoto rats (WKY) as control group rats. Blood pressure of abdominalis aorta of each weeks SHR and WKY were measured by BL-420F experimental system of biological function. The arteria mesenteric minor (AMM) were isolated in blunt dissection method. The vascular smooth muscle cells (VSMCs) of AMM were isolated with prolease. The potassium current, the current after BKCa were blockaded by Tetraethylammonium (TEA) and the capacitance of membrane (Cm) of VSMCs of AMM were recorded with using whole cell patch clamp, and calculated the BKCa current and the BKCa current density. Probe the correlation of the changes of BKCa current density with MABP during aging. RESULTS: The potassium current density and BKCa current density of VSMCs of AMM of SHR were decreasing during aging, however, the changes of WKY had no statistically significance (P > 0.05). The BKCa current density was extremely correlative with MABP in SH R (the values of r were -0.7174), in WKY, the BKCa current density was correlative with MAB P r = -0.4832. CONCLUSION: BKCa current and current density attenuate with aging, the level of blood pressure is response of the attenuated degree. The BKCa current density is extremely correlative with the blood pressure.
