Figure 2

(A–K) Mouse islets were dispersed and cultured on uncoated glass (A and B) or plastic (C–K) for 72 hours (A, B, D, G, and K) or 48 hours (C, E, F, and H–J). β cell proliferation increased in 15 mM glucose as measured by BrdU incorporation (A and B; n = 3) and by abundance of proliferation markers Ki67 and PCNA by qPCR (C; n = 3) or immunoblot (D). Arrowheads in A indicate BrdU-positive β cells. UPR markers BiP and calreticulin (CalR) were increased in proliferating islet cell cultures (D, immunoblot; E, qPCR, n = 3). All 3 classical UPR pathways were activated in 15 mM glucose: sXbp (F; RNA assay, n = 3), p-eIF2α (G, immunoblot), and ATF6 (G, immunoblot; H, qPCR, n = 3), as well as ATF6 and XBP transcriptional targets (I and J, n = 3). Decompensation marker CHOP was highest in 5 mM glucose (K). Immunoblots in D, G, and K are representative examples of n = 5–9 independent replicates; quantifications for D, F, G, and K are found in Supplemental Figure 2. HK, housekeeping gene. Images in A acquired at ×200 magnification. (A–K) The numbers 5, 7.5, and 15 refer to glucose concentration. Data are represented as mean ± SEM; *P < 0.05 and **P < 0.01 by Student’s t test.