Coordinated epithelial NHE3 inhibition and barrier dysfunction are required for TNF-mediated diarrhea in vivo
J. Clin. Invest. Daniel R. Clayburgh, et al. 116:2682 doi:10.1172/JCI29218 [Go to this article.]

Figure 1
Administration of TNF and LIGHT induces barrier dysfunction similar to that caused by anti-CD3 injection, but only TNF causes net water secretion. (A) In vivo perfusion assays show that anti-CD3 causes a large increase in BSA flux (P < 0.0001 versus control). The MLCK inhibitor PIK completely prevented this increased BSA flux, which was also attenuated by anti-TNF or use of LTβR^–/– mice. (B) Anti-CD3 injection reverses water movement, from net water absorption in control animals to net water secretion (P < 0.0001). PIK restored water flow to net absorption, although absorption was still significantly less than in control animals. Anti-TNF completely restored water absorption after anti-CD3 injection. No significant water absorption or secretion was observed in LTβR^–/– animals treated with anti-CD3 (P < 0.001). (C) Two hours following anti-CD3 injection, TNF, LIGHT, and IFN-γ mRNA were assessed in intestinal mucosa using quantitative real-time PCR. Anti-CD3 caused significant increases in transcripts for all 3 cytokines (P < 0.001). (D) Either TNF or LIGHT, but not IFN-γ, causes significant increases in BSA flux, though not as large as that caused by anti-CD3. Simultaneous injection of TNF and LIGHT led to a larger increase in BSA flux that resembled the increase following anti-CD3 injection. (E) While IFN-γ does not alter water movement, TNF reverses water movement from net water absorption to net water secretion in a manner similar to anti-CD3. In contrast, LIGHT caused an increase in water absorption (P = 0.03). Simultaneous TNF and LIGHT treatment caused water secretion similar to that caused by treatment with TNF alone.