title: Oncostatin M, a cytokine released by activated mononuclear cells, induces epithelial cell-myofibroblast transdifferentiation via Jak/Stat pathway activation.
abstract: Interactions between inflammatory infiltrates and resident tubular epithelial cells may play important roles in the development of tubulointerstitial fibrosis, by promoting epithelial cell-myofibroblast transdifferentiation (EMT). Human proximal tubular epithelial cells transdifferentiated to myofibroblasts after treatment with activated PBMC conditioned medium. mRNA and protein levels for alpha-smooth muscle actin, collagen I, and fibronectin EDA(+) (markers for the myofibroblastic phenotype) were increased, whereas those for E-cadherin and cytokeratin 19 (markers for the epithelial phenotype) were decreased. cDNA microarray analysis was used to identify other changes in gene expression that might point to novel molecular mechanisms driving EMT. Of 1176 array genes, 61 demonstrated at least a twofold change at at least two consecutive time points, of the five time points examined (0.5, 4, 8, 16, and 48 h). Of these genes, 59% were upregulated and 41% were downregulated. The array indicated upregulation of expression of the oncostatin M (OSM)-specific receptor beta subunit from 4 to 48 h after exposure of kidney epithelial cells to activated PBMC conditioned medium, which contained high levels of OSM. In additional experiments, it was demonstrated that OSM induced EMT. OSM activated the Jak/Stat signaling pathway in epithelial cells, and a specific inhibitor of Jak2 blocked both its phosphorylation after exposure to OSM and the induction of alpha-actin and loss of cytokeratin 19 expression. Therefore, OSM is a novel inducer of EMT and is likely to be one of several cytokines produced by inflammatory infiltrates that contribute to this and subsequent tubulointerstitial fibrosis.
authors.affiliation: Teijin Biomedical Laboratory, Medical Research Council Technology, London, UK.
authors.forename: Joanna
authors.initials: J
authors.lastname: Nightingale
authors.forename: Sharmila
authors.initials: S
authors.lastname: Patel
authors.forename: Naotaka
authors.initials: N
authors.lastname: Suzuki
authors.forename: Roger
authors.initials: R
authors.lastname: Buxton
authors.forename: Ken-ichro
authors.initials: KI
authors.lastname: Takagi
authors.forename: Jun
authors.initials: J
authors.lastname: Suzuki
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Sumi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Imaizumi
authors.forename: Roger M
authors.initials: RM
authors.lastname: Mason
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D016207:Cytokines / Q000502:physiology*; D004847:Epithelial Cells / Q000166:cytology*; D005347:Fibroblasts / Q000166:cytology*; D015870:Gene Expression; D006801:Humans; D007684:Kidney Tubules / Q000166:cytology; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D032446:Myoblasts / Q000166:cytology*; D020411:Oligonucleotide Array Sequence Analysis; D053683:Oncostatin M; D010455:Peptides / Q000502:physiology*; D015398:Signal Transduction; D019459:Urothelium / Q000166:cytology
chemical_list: D016207:Cytokines; C508351:OSM protein, human; D010455:Peptides; D053683:Oncostatin M