Figure 8.

Phosphatidylcholine depletion in IECs leads to ER stress and UPR activation. (A) Representative electron micrographs of the ER in colonic epithelial cells of control mice and CTα^IKO mice. Arrow indicates ER. (B) The mRNA abundance of sXBP1, Ddit3, and Hspa5 in the colons of control mice and CTα^IKO mice (n = 5/group). (C) Representative Western blots and (D) quantification of spliced XBP1, PERK, and ATF6 relative to loading controls in the colons of control mice and CTα^IKO mice (n = 4–8/group). (E) The mRNA abundance of Atf4, Atf5, and Eif4ebp1 in the colons of control mice and CTα^IKO mice (n = 5/group). (F) Representative Western blot and (G) quantification of P62 relative to tubulin in the colons of control mice and CTα^IKO mice (n = 8/group). (H) Representative electron micrographs of autophagic vesicles in colonic epithelial cells of control mice and CTα^IKO mice. Arrow indicates autophagosome. (I) Pathology scores for control mice and CTα^IKO mice treated with and without PBA (n = 3–5/group). (J) Goblet cell depletion scores for control mice and CTα^IKO mice treated with and without PBA (n = 3–5/group). (K) The mRNA abundance of sXBP1, Ddit3, and Hspa5 in the colons of control mice and CTα^IKO mice treated with and without PBA (n = 3–5/group). (L) Colon weight of control mice and CTα^IKO mice treated with and without PBA (n = 3–5/group). Values are means ± SEM. (I–L) Columns that do not share a letter (a or b) are significantly different (α = .05). ∗P < .05, ∗∗∗P < .001, and ∗∗∗∗P < .0001. GAPDH, glyceraldehyde-3-phosphate dehydrogenase; sXBP1, spliced XBP1.