Figure 2.

Autophagy relieves ER stress to facilitate mucus secretion from goblet cells

(A) Colonic goblet cell numbers per crypt.

(B) Quantification of the mucus-filled cytoplasmatic area of colonic goblet cells.

(C) Expression levels of Muc2, which encodes the mucus-forming protein MUC2 in the colons of mice via RNA sequencing.

(D) Heatmap depicting differentially expressed ER stress response genes with an FDR < 0.01. Each column represents a mouse and each row a gene.

(E) Representative western blot of mouse colons detected with the indicated antibodies.

(F) Densitometry analysis of western blots as in (E).

(G) qPCR analysis of Hspa5 mRNA in goblet cells isolated from colonic tissue via fluorescence-activated cell sorting.

(H) Quantification of protein levels of CHOP, specifically in colonic goblet cells via immunohistochemistry.

(I) Scheme depicting ER stress activation via thapsigargin.

(J and K) Measurements of mucus thickness in colonic sections from mice treated with thapsigargin as indicated, and stained with Alcian blue. Scale bars, 50 μm.

(L) Scheme depicting regulation of autophagy activation via Bcl-2 phosphorylation and its suppression in Bcl2^AAA mice.

(A–C, F–H, and K) Each dot represents a mouse. ns, not significant; ^∗p < 0.05; ^∗∗∗p < 0.001; ^∗∗∗∗p < 0.0001. (A–C and F–H) Student’s t test; (K) one-way ANOVA; WT, wild type; F121A, Becn1^F121A; AAA, Bcl2^AAA; AB, Alcian blue; RPKM, reads per kilobase per million mapped reads; MFI, mean fluorescent intensity; RQ, relative quantity.