FIGURE 3.

Glucose deprivation, not hypoxia, activates the UPR in HREC. A, HREC were cultured in glucose-deprived medium or in standard medium with or without hypoxia for 24 h, or with 2.5 μm tunicamycin for 8 h. GRP78, CHOP, and sXBP transcript levels were measured by qRT-PCR and are presented as the mean ± S.E. relative to levels after 24 h of culture with standard conditions in four independent experiments. GRP78 protein expression was determined by immunoblotting. The immunoblot shown is representative of three independent experiments. *, p < 0.05. B, HREC were cultured with 2.5 μm tunicamycin for 8, 16, and 24 h. VEGFA, bFGF, ANG, and PDGFB transcript levels were measured by qRT-PCR and are presented as the mean ± S.E. relative to levels in non-treated cells in four independent experiments. The dotted line figures the expression level (= 1) of each gene in basal condition. C, HREC were cultured with 2.5 μm tunicamycin for 16 h, and the secretion of VEGFA, bFGF, and ANG in the medium was quantified by ELISA.