title: Tacrolimus Modulates TGF-β Signaling to Induce Epithelial-Mesenchymal Transition in Human Renal Proximal Tubule Epithelial Cells.
abstract: Epithelial-mesenchymal transition (EMT), a process which describes the trans-differentiation of epithelial cells into motile mesenchymal cells, is pivotal in stem cell behavior, development and wound healing, as well as contributing to disease processes including fibrosis and cancer progression. Maintenance immunosuppression with calcineurin inhibitors (CNIs) has become routine management for renal transplant patient, but unfortunately the nephrotoxicity of these drugs has been well documented. HK-2 cells were exposed to Tacrolimus (FK506) and EMT markers were assessed by RT PCR and western blot. FK506 effects on TGF-β mRNA were assessed by RT PCR and TGF-β secretion was measured by ELISA. The impact of increased TGF-β secretion on Smad signaling pathways was investigated. The impact of inhibition of TGF-β signaling on EMT processes was assessed by scratch-wound assay. The results presented in this study suggest that FK506 initiates EMT processes in the HK-2 cell line, with altered expression of epithelial and myofibroblast markers evident. Additionally, the study demonstrates that FK506 activation of the TGF-β/ SMAD pathways is an essential step in the EMT process. Overall the results demonstrate that EMT is heavily involved in renal fibrosis associated with CNI nephrotoxicity.
authors.affiliation: Centre for Cell Signaling and Inflammation, Department of Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK. j.bennett@imperial.ac.uk.
authors.forename: Jason
authors.initials: J
authors.lastname: Bennett
authors.affiliation: Renal Disease Research Group, School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin 4, Ireland. hilary.cassidy@ucdconnect.ie.
authors.forename: Hilary
authors.initials: H
authors.lastname: Cassidy
authors.affiliation: Renal Disease Research Group, School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin 4, Ireland. craig.slattery@ucd.ie.
authors.forename: Craig
authors.initials: C
authors.lastname: Slattery
authors.affiliation: Renal Disease Research Group, School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin 4, Ireland. Michael.P.Ryan@ucd.ie.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Ryan
authors.affiliation: Renal Disease Research Group, School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin 4, Ireland. tara.mcmorrow@ucd.ie.
authors.forename: Tara
authors.initials: T
authors.lastname: McMorrow
keywords: Epithelial-mesenchymal transition; fibrosis; tacrolimus