Fig. 6.

PAX4-regulated ER homeostasis prevents cell degeneration. Islet PAX4, galectin-9 (Lgals9) and calreticulin (Calr) transcript levels were assessed in (a) PAX4 or (b) PAX4R129W transgenic mice treated (black bars) or not treated (white bars) with DOX for 1 month. The relative mRNA levels were normalised to transcript levels of the housekeeping gene β-actin. Data were calculated as fold change compared with the values in control, non-DOX-treated animals. n = 3, **p < 0.01 and *p < 0.05. (c) Pax4 or Pax4R129W induction in DOX-treated islets was qualitatively assessed through DsRed fluorescence. Scale bar, 10 μm. (d) Control (white bars), PAX4-expressing (black bars) and PAX4R129W-expressing (grey bars) islets were then challenged with 1 μmol/l thapsigargin or not challenged and apoptosis was measured by ELISA. Results expressed as per cent change compared with control non-thapsigargin-treated islets. n = 5, *p < 0.05. (e) Pax4, Calr and cyclophylin expression levels were measured in MIN6 cells treated with siControl (white bars) and siPax4 (black bars). mRNA levels were normalised to the transcript levels of the housekeeping gene β-actin. Data were calculated as fold change compared with the values in siControl-treated cells. n = 4, *p < 0.05. (f) Apoptosis was evaluated in control MIN6 (white bars), and cells treated with siControl (grey bars) or siPax4 (black bars), untreated or treated with thapsigargin. Results are expressed as fold change compared with control non-thapsigargin-treated cells. n = 5, *p < 0.05