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. 2018 Feb 21;37(7):e98311. doi: 10.15252/embj.201798311

Figure 1. mTORC1 activity undergoes dramatic changes during stomach and pancreas metaplastic injury response.

Figure 1

  • A, B
    Digestive‐enzyme‐secreting (zymogenic) mature cell populations in the stomach (A) and pancreas (B) are recruited back into the cell cycle to fuel metaplasia in response to large‐scale injury. Digestive enzyme expression (red) decreases, and markers of mucous neck cells (green, stomach) or duct cells (green, pancreas) increase in metaplastic, proliferating cells (red + green = yellow). Stomach is further characterized by loss of acid‐secreting parietal cells (blue). (B) Representative epifluorescence images of mouse gastric corpus glands during homeostasis, early after injury (HD‐Tam 12 h) and at maximal metaplastic response (HD‐Tam Day 3), stained for mTORC1 activity using a downstream target, pS6 as a proxy. Green, pS6; red, GIF (gastric intrinsic factor, a chief cell marker); white, GSII (a mucous neck cell marker); blue, DAPI. Right—higher magnification images of boxed areas on left focus exclusively on the base of the unit where the digestive‐enzyme‐secreting cells are reprogramming. Yellow dashed area outlines the base of a single gastric unit. Scale bar, 20 μm; boxed area pull out, 10 μm.
  • C
    Western blot of pS6 (red) and β‐tubulin control (green) from whole corpus protein extracts at various injury time points; pS6 (240/244 or 235/6) vs. tubulin fluorescent intensity from replicate blots quantified below (error bars = standard deviation). *P < 0.05, ***P < 0.001. Statistical analysis with both antibodies was done using ANOVA with a post hoc Dunnett's test.
  • D
    Representative epifluorescence images of pS6 staining of pancreas during homeostasis, acute injury (cerulein 12 h), and maximal injury (cerulein day 5). Green, pS6; red, amylase; blue, DAPI. Boxed areas on left depicted at higher magnification on right. Scale bar, 20 μm; boxed area pull out, 10 μm.