Figure 2. Formation of hyperproliferative crypt nodules and MT-UPR activation is independent of CHOP-mediated signalling.

(a) Schedule for oral tamoxifen administration to induce HSP60 deficiency in IEC of adult Chop^−/− Hsp60^Δ/ΔIEC mice. Agarose gels showing the presence of the knockout allele specifically in IEC isolates. (b) Representative H&E and corresponding HSP60 IHC stainings of Chop^−/− Hsp60^Δ/ΔIEC mice along the intestinal tract. Images of HSP60 IHC in higher magnification show HSP60-deficient villus versus HSP60-positive crypt regions of the jejunum. HSP60-positive crypt nodules in Chop^−/− Hsp60^Δ/ΔIEC mice were counted along the intestinal tract using HSP60 IHC stainings. The graph represents quantifications of Hsp60^Δ/ΔIEC mice (N=6) with >100 crypts counted per animal. Lines indicate mean numbers. One-way analysis of variance (ANOVA) followed by Dunn's test was used to test for significance. (c) Quantification of HSP60-positive and HSP60-negative crypt numbers and total area of HSP60-positive crypt nodules of Hsp60^Δ/ΔIEC and Chop^−/− Hsp60^Δ/ΔIEC mice revealed no differences between genotypes (N=6); unpaired t-tests. Bars represent means+s.e.m. Lines in the dot plot indicate mean numbers. (d) qRT–PCR analysis of MT-UPR-associated genes in villus (upper panel) and crypt (low panel) IEC isolated from Hsp60^Δ/ΔIEC (N=6) and Chop^−/− Hsp60^Δ/ΔIEC mice (N=6) and corresponding controls (N=5 and N=6). Statistical analysis was performed using unpaired t-tests. Asterisks indicate significant differences *P<0.05, **P<0.01, ***P<0.001; NS, not significant.