Figure 2
Gal-1 signals apoptosis in mouse enterocytes. (a) Epithelial cells isolated from duodenal mucosa were incubated with 10 μM rGal-1 and annexin V binding was analyzed by flow cytometry. Left panel: enterocytes extracted at time zero (dashed line), black histogram corresponds to cells incubated with culture medium during different time periods and gray histogram corresponds to cells incubated with Gal-1 10 μM. Right panel summarizes the results of four independent experiments; white column corresponds to cells incubated without rGal-1 whereas dark column corresponds to cells exposed to Gal-1 (mean values±S.E.M.). Statistically significant differences P<0.05 are denoted as starred values (*). (b) Phosphatidylserine exposure induced by rGal-1. Cells were incubated for 16 h with different concentrations of Gal-1 and analyzed by annexin V staining and flow cytometry. Data represent fold increase±S.E.M. of percentages of annexin V+, PI− cells relative to cells incubated with medium alone. Results correspond to eight independent experiments. Experiments were also carried out in the presence of 100 mM lactose. Statistically significant differences P<0.05 are denoted as starred values (*). (c) Apoptosis of enterocytes induced by rGal-1 as shown by TUNEL assay and flow cytometry. Cells were incubated with medium (upper left panel) or with 10 μM Gal-1 during 16 h (upper right panel). Data are representative of four independent experiments giving similar results. Data in the bottom panel show the mean value±S.E.M. of four parallel and independent experiments (***P<0.01)
