MPA Modulates Tight Junctions' Permeability via Midkine/PI3K Pathway in Caco-2 Cells: A Possible Mechanism of Leak-Flux Diarrhea in Organ Transplanted Patients
Open Access
- 26 June 2017
- journal article
- research article
- Published by Frontiers Media SA in Frontiers in Physiology
- Vol. 8, 438
- https://doi.org/10.3389/fphys.2017.00438
Abstract
Mycophenolic acid (MPA) is prescribed to prevent allograft rejection in organ transplanted patients. However, its use is sporadically linked to leak flux diarrhea and other gastrointestinal (GI) disturbances in around 75% of patients through yet unknown mechanism. Recently, we identified Midkine as a modulator of tight junctions (TJs) permeability in MPA treated Caco-2 monolayer. In the present study, we investigated the possible involvement of Midkine dependent PI3K pathway in alteration of TJs under MPA treatment. Caco-2 cells were grown as monolayer to develop TJs and were treated for 72 hours with DMSO (control) or MPA in presence and absence of Midkine inhibitor (iMDK) or PI3K inhibitors (LY/AMG). Caco-2 monolayer integrity was assessed by transepithelial electrical resistance (TEER) and FITC-dextran assays. Our functional assays showed that PI3K inhibitors (LY/AMG) can significantly inhibit the compromised TJs integrity of MPA-treated Caco-2 cells monolayer. Chromatin immunoprecipitation analyses showed a significant epigenetic activation of Midkine, PI3K, Cdx-2, and Cldn-2 genes and epigenetic repression of Cldn-1 gene after MPA treatment. The MPA-induced epigenetic alterations were further confirmed by mRNA and protein expression analysis. Collectively, our data show that PI3K pathway as the downstream target of Midkine which in turn modulates p38MAPK and pAKT signaling to alter TJs permeability in Caco-2 cell monolayers treated with MPA. These results highlight the possible use of either Midkine or PI3K inhibitors as therapeutic agents to prevent MPA induced GI disturbances.Keywords
Funding Information
- Deutsche Forschungsgemeinschaft
- Deutscher Akademischer Austauschdienst
- Higher Education Commission, Pakistan
This publication has 84 references indexed in Scilit:
- Interleukin-6 (IL-6) Regulates Claudin-2 Expression and Tight Junction Permeability in Intestinal EpitheliumPublished by Elsevier BV ,2011
- Occludin S408 phosphorylation regulates tight junction protein interactions and barrier functionThe Journal of cell biology, 2011
- Genome-wide Analysis of CDX2 Binding in Intestinal Epithelial Cells (Caco-2)Journal of Biological Chemistry, 2010
- Epithelial Myosin Light Chain Kinase Activation Induces Mucosal Interleukin-13 Expression to Alter Tight Junction Ion SelectivityPublished by Elsevier BV ,2010
- Caveolin-1–dependent occludin endocytosis is required for TNF-induced tight junction regulation in vivoThe Journal of cell biology, 2010
- The tight junction protein CAR regulates cardiac conduction and cell–cell communicationThe Journal of Experimental Medicine, 2008
- Analyzing real-time PCR data by the comparative CT methodNature Protocols, 2008
- AKT/PKB Signaling: Navigating DownstreamCell, 2007
- Requirement of ZO-1 for the formation of belt-like adherens junctions during epithelial cell polarizationThe Journal of cell biology, 2007
- Trypan Blue Exclusion Test of Cell ViabilityCurrent Protocols in Immunology, 1997