ABSTRACT
Aim To investigate the effects of high glu-cose on cholesterol metabolism in renal tubular cells and the intervention of the anthocyanins. Methods HK-2 cells were grown in the DMEM medium supple-mented with 10% FBS and were divided into 5 groups:normal glucose group, high glucose group, mannitol group, C3G group and Cy group. Effect of anthocya-nins on cell viability was detected with MTT, and cho-lesterol accumulation was detected with Amplex Red Cholesterol Assay kit and Filipin staining. Expression of ABCA1 was detected with RT-qPCR and Western Blot. Results In compared with control groups, HG significantly promoted cholesterol mass inside the cell and decreased the cholesterol concentration in the me-dium after treatment for 24 h or 48 h. The levels of mRNA and protein of ABCA1 were detected with RT-qPCR and Western blot, and both were decreased in the presence of HG. Whereas treatment with C3G and Cy markedly attenuated HG-induced cholesterol mass inside the cell by up-regulating the expression of AB-CA1. Conclusions High glucose can reduce the ex-pressions of the ABCA1, and then decrease cholesterol efflux and increase the cholesterol accumulation in HK-2 cells. Anthocyanins can decrease cholesterol accu-mulation by up-regulating the expression of ABCA1.
ABSTRACT
Aim Toexplorethemechanismofupregu-lation of osteopontin ( OPN ) expression induced by high glucose in human renal tubular epithelial cells (HK-2cells).Methods Afterstimulationwithhigh-glucose (25 mmol·L-1 ) culture medium, HK-2 cells were then treated with the specific inhibitors or siRNA to inhibit the activity of PI3K and/or mTOR. Subse-quently, Real-time PCR was used to investigate the mRNA level of OPN, and Western blot was performed to detect the protein expression of OPN, p-AKT, p-S6,RaptorandRictor.Results Theexpressionlevel of OPN was increased in a time-dependent manner in HK-2 cells followed by high-glucose stimulation. The mRNA level of OPN peaked at 48 h; while the protein expression of OPN reached the highest level at 72h. Meanwhile, high glucose activated the PI3K/AKT/mTOR signaling pathway. Moreover, inhibition of the PI3 K/AKT/mTOR pathway by LY294002 and/or rapa-mycin led to significant down-regulation of OPN. Addi-tionally, the treatment with Raptor siRNA, but not Rictor siRNA resulted in reduction of OPN expression. Conclusion Highglucoseincreasestheexpressionof OPN through the activation of PI3 K/AKT/mTORC1 signaling pathway in HK-2 cells.