FIGURE 6.

bFGF expression is regulated by PERK. A, HREC were transfected with siRNAs targeting PERK or control, non-targeted (scramble) siRNAs. Left: bFGF transcript levels were measured by qRT-PCR after the cells had incubated in glucose-free medium for 48 h and compared with levels after 48 h of culture with standard conditions (n = 4). Right: secretion of bFGF in the medium was quantified by ELISA after the cells had incubated in glucose-free or standard medium for 48 h (n = 3). *, p < 0.05. B, HREC were incubated in glucose-free or standard medium and treated with or without 25 μm salubrinal for 48 h. Left: bFGF transcript levels were measured by qRT-PCR and compared with levels after 48 h of culture with standard conditions (n = 3). Right: secretion of bFGF in the medium was quantified by ELISA (n = 3). *, p < 0.05. C, HREC were transfected with siRNAs targeting IRE1α or control, non-targeted (scramble) siRNAs. The secretion of bFGF in the medium was quantified by ELISA after the cells had incubated in glucose-free or standard medium for 48 h (n = 3). D, HREC were transfected with siRNAs targeting ATF6 or control, non-targeted (scramble) siRNAs. The secretion of bFGF in the medium was quantified by ELISA after the cells had incubated in glucose-free or standard medium for 48 h (n = 3).