ABSTRACT
Objective To investigate the effect of phosphoinositide-3-kinase inhibitor LY294002 on the differentiation of human embryonic stem cells (HESC) into more mature insulin-producing cells. Methods HESCs were induced to differentiate into insulin-producing cells through five stages. Nicotinamide and B27 (group B27), nicotinamide and LY294002 (group LY) were used to induce the nesting positive cells into mature insulin-producing cells. The morphological change of each stage was observed under microscope , and expressions of insulin, c-peptide, somatostatin and glucagon were identified by immunofluorescence staining. Results After 14 days in stage 5 , there was no significant difference in rate of insulin positive cells between group LY and group B27 (P﹥0.05), but rates of somatostatin and glucagon positive cells in group LY were lower than those in group B27(P﹤0.05). Furthermore, the co-stained rate of somatostatin and insulin in group LY was also lower than that in group B27 (P﹤0.05). Conclusion HESCs can be induced to differentiate into more mature insulin-producing cells by phosphoinositide-3-kinase inhibitor LY294002 in serum-free culture medium.
ABSTRACT
Background Protein kinase B (Akt) is the center of multiple cellular signaling pathways,and it participates in the regulation of cell function,such as proliferation,migration,and metabolism of cells.Phosphoinositide 3-kinase (PI3K) promotes activation of Akt and therefore triggers many signal pathways.PI3K inhibitor can silent Akt,but whether it can affect the biological behavior of lens epithelial cells (LECs) during the posterior capsular opacity (PCO) is worthy of investigation.Objective This study was to explore the effect of LY294002,a PI3K inhibitor,on Akt activation in human LECs.Methods Human LECs strain,HLEC-B3 cells,were cultured and passaged.The cells were incubated to 96-well plate for 24 hours,then LY294002 was added with the final concentration at 0,10,20,30,40,50,60,70,80 μmol/L,respectively.After incubation for 24 hours,cell counting kit-8 (CCK-8) was used to detect the inhibitory rate of cell proliferation.Transforming growth factor-β2 (TGF-β2) of 10 μg/L was added in the medium of cells as TGF-β2 group,TGF-β2 + LY294002 (20 μmol/L) was used to coculture the other group of cells,and the cells without TGF-β2 and LY294002 served as the control group.Phosphorylation of Akt (p-Akt) in the cells was detected by laser scan confocal immunofluorescence microscope.The expression level of p-Akt was evaluated using Western blot.Results CCK-8 assay showed that the A value of the cells was gradually reduced with the increase of LY294002 concentration (Fgroup =9.72,P =0.00),but the A value was significant raised along with the lapse of time (Ftime =1737.54,P=0.00).Confocal immunofluorescence revealed that a little of p-Akt was expressed in the control cells.After induced by TGF-β2,lots of red fluorescence of p-Akt was seen in cells around the cell membranes.But in the TGF-β2+LY294002 co-culture cells,the fluorescence of Akt was much weaker.Western blot showed that the expression level of p-Akt was 0.91±0.08,1.48±0.13 and 0.95±0.19 in the control group,TGF-β2 group and TGF-β2 +LY294002 group,respectively,with a significant difference among the three groups (F =15.04,P =0.00).Conclusions LY294002 can inhibit the activation of Akt induced by TGF-β2.LY294002 may have utility in the prevention and treatment of PCO.