The role of luminal contents and intestinal alkaline phosphatase in patients with pouchitis after ileal-pouch anal anastomosis for ulcerative colitis
Final Report Abstract
In this research project, the anti-inflammatory potential and functions of the gut brush border enzyme intestinal alkaline phosphatase (IAP) and the inflammatory properties of ileal contents were tested in patients with IBD. We could show that endogenous IAP functions as a modulator of the stress response and inflammatory pathways in the intestinal epithelium. Overexpression of human IAP significantly reduced mRNA-levels of inflammatory cytokines (TNF-α, IL-1β, IL-8) in Caco-2 cells whereas IAP deletion significantly increased the expression of the TNF-α, IL-1β and IL-8 genes. However, exogenous IAP did not reduce transcript levels of inflammatory cytokines in Caco2 cells. Functional analysis and identification of IAP-binding proteins were performed using Liquid Chromatography-tandem Mass Spectrometry (LC-MS) after immunoprecipitation of IAP complexes from Caco-2 cells in-vitro. Analysis of IAP protein complexes showed that IAP binds to key modulators of the NFκB, TNF-α and TLR-4 pathways. To find potential activators of endogenous IAP we run a kinase library screening. The screening revealed specific kinase inhibitors which activated endogenous IAP. These inhibitors corresponded to the pathways we detected by functional analysis of our mass spectrometry data. These mostly commercially available inhibitors may represent new therapeutics for inflammatory disorders of the gut. Furthermore, we could show that IAP activity was significantly lower in ileal contents from patients with ulcerative colitis than in patients without underlying inflammatory disease. In addition, TNF-a levels were significantly higher in ileal fluid of IBD patients than in controls whereas IL-8 levels were similar. The inflammatory response of epithelial cancer cell lines (Caco2 and T84) exposed to human ileal fluid from various patient groups was not reproducible in multiple repetitions. However, the inflammatory response of THP1 monocytes exposed to ileal fluid showed a reproducible, individual cytokine profile for each patient and did not correlate with the cytokine levels in the original sample or the underlying disease. The individual inflammatory response profile of each patient could serve as a basis for determining the risk for recurring disease or as a predictor for pouchitis in stoma patients with IBD.
Publications
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Endogenous intestinal alkaline phosphatase controls inflammatory pathways and cellular homeostasis in the gut. Z Gastroenterol 2016; 54 - KV024
Kühn F, Hamarneh SR, Ramirez JM, Munoz AR, Morrison SA, Gul SS, Adiliaghdam F, Hodin RA
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Inflammatory Properties of Ileal Fluid from Patients with IBD. Massachusetts Chapter of the American College of Surgeons 2017 (Boston, MA, USA)
Kuehn F, Liu F, Adiliaghdam F, Liu E, Farber M, Vasan R, Ramirez JM, Hamarneh SR, Hodin RA
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Loss of Intestinal Alkaline Phosphatase Leads to Distinct Chronic Changes in Bone Phenotype. Journal of Surgical Research, Vol. 232. 2018, pp. 325-331.
Kuehn F., Adiliaghdam .F, Hamarneh S.R., Vasan R., Liu E., Liu Y., Ramirez J.M., Hoda R.S., Munoz A.R., Ko F.C., Armanini M., Brooks D.J., Bouxsein M.L., Demay M.B., Hodin R.A.
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(2020). Intestinal alkaline phosphatase targets the gut barrier to prevent aging. JCI insight, 5(6)
Kuehn F, Adiliaghdam F, Hamarneh SR, Najibi M, Tsurumi-Wang A, Hoda RS, Ramirez JM, Dhole Y, Labed SA, Munoz AR, Liu E, Vasan R, Liu Y, Samarbafzadeh E, Nunez RA, Farber MZ, Chopra V, Malo MS, Irazoqui JE, Rahme LG, Hodin RA
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Intestinal alkaline phosphatase targets the gut barrier to prevent aging.
JCI Insight, Vol.5. 2020, Issue 6: e134049.
Kühn F., Adiliaghdam F., Cavallaro P.M., Hamarneh S.R., Tsurumi A., Hoda R.S., Munoz A.R., Dhole Y., Ramirez J.M., Liu E., Vasan R., Liu Y., Samarbafzadeh E., Nunez R.A., Farber M.Z., Chopra V., Malo M.S., Rahme L.G., Hodin R.A.
