Endoplasmic reticulum stress and forkhead box protein O1 inhibition mediate palmitic acid and high glucose-induced β-cell dedifferentiation

Figure 2 High glucose and palmitic acid increased aldehyde dehydrogenase 1 family member A3 level and pancreatic and duodenal homeobox 1 translocation. A: Immunofluorescence staining with 4’,6-Diamidino-2’-phenylindole (DAPI) (blue), insulin (red) and aldehyde dehydrogenase 1 family member A3 (Aldh1a3) (green) of INS-1 cell treated with bovine serum albumin (BSA) (control), high glucose plus palmitate acid (Glu + PA) or high glucose plus palmitate acid plus AS1842856 (Glu + PA + AS). Scale bars indicate 20 μm. Arrows indicate the Aldh1a3-positive cell. The lower panel indicates magnified images, shown in dashed squares. Scale bars indicate 10 μm; B: Quantification of the fluorescence intensity of insulin, Aldh1a3, and the ratio of Aldh1a3/insulin. Three different experiments were performed; C: Immunofluorescence with DAPI (blue) and pancreatic and duodenal homeobox 1 (Pdx1) (magenta) of INS-1 treated with BSA (control), high Glu + PA, or high Glu + PA + AS. Scale bars indicate 20 μm; D: Quantification of Pdx1 intensity in nuclei, and three different experiments were performed. Data are presented as means ± SEM. ^aP < 0.05. ^bP < 0.01. ^cP < 0.001. ^dP < 0.0001. Glu: Glucose; PA: Palmitic acid; AS: AS1842856; Pdx1: Pancreatic and duodenal homeobox 1; Aldh1a3: Aldehyde dehydrogenase 1 family member A3; DAPI: 4’,6-Diamidino-2’-phenylindole.