The Phosphatase PHLPP2 Plays a Key Role in the Regulation of Pancreatic Beta-Cell Survival

Figure 1

INS-1 cells maintained for 12–15 passages at 30 mM glucose concentrations show reduced insulin synthesis and secretion and altered expression of prosurvival markers. INS-1 was maintained at high (30 mM, INS-1 HG) or normal (11.2 mM, INS-1 NG) glucose concentrations for 12–15 passages. (a) Insulin mRNA levels were assessed by real-time RT-PCR; n = 6, indicates significant () differences for INS-1 NG vs INS-1 HG. (b) Glucose-stimulated insulin secretion was assessed by measuring with a specific Elisa kit insulin concentration in medium obtained from INS-1 NG and INS-1 HG exposed to increasing glucose concentrations (5.6, 11.2, 15.6, and 22.4 mM) for 20 minutes; n = 4, indicates significant () differences for INS-1 NG vs INS-1 HG. (c) Representative western blot images of cell survival markers levels in INS-1 HG and INS-1 NG: Bad (upper panel), Bcl-xL (middle-upper panel), cleaved caspase-3 (middle-lower panel), and LC3-II (lower panel). (d) Graph of the mean changes of densitometric values of cell survival markers in INS-1 NG and INS-1 HG; n = 5–10, indicates significant () differences for INS-1 NG vs INS-1 HG.

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