摘要
Restoration of kidney tubular epithelium following sublethal injury sequentially involves partial epithelial–mesenchymal transition(pEMT),proliferation,and further redifferentiation into specialized tubule epithelial cells(TECs).Because the immunosuppressant cyclosporine-A produces pEMT in TECs and inhibits the peptidyl-prolyl isomerase(PPIase)activity of cyclophilin(Cyp)proteins,we hypothesized that cyclophilins could regulate TEC phenotype.Here we demonstrate that in cultured TECs,CypA silencing triggers loss of epithelial features and enhances transforming growth factorβ(TGFβ)-induced EMT in association with upregulation of epithelial repressors Slug and Snail.This pro-epithelial action of CypA relies on its PPIase activity.By contrast,CypB emerges as an epithelial repressor,because CypB silencing promotes epithelial differentiation,prevents TGFβ-induced EMT,and induces tubular structures in 3D cultures.In addition,in the kidneys of CypB knockout mice subjected to unilateral ureteral obstruction,inflammatory and pro-fibrotic events were attenuated.CypB silencing/knockout leads to Slug,but not Snail,downregulation.CypB support of Slug expression depends on its endoplasmic reticulum location,where it interacts with calreticulin,a calcium-buffering chaperone related to Slug expression.As CypB silencing reduces ionomycin-induced calcium release and Slug upregulation,we suggest that Slug expression may rely on CypB modulation of calreticulin-dependent calcium signaling.In conclusion,this work uncovers new roles for CypA and CypB in modulating TEC plasticity and identifies CypB as a druggable target potentially relevant in promoting kidney repair.
基金
supported in part by grants from Ministerio de Cienciae Innovacion(SAF 201459945-Rand SAF 201789989-R to A.M.)
the Fundacion Senefro(SEN 2019 to A.M.),Instituto de Salud Carloslll(PIE13/00027)
Red de Investigacion Renal REDinREN(12/0021/0013).KAN.is supported by Nationa Mnstitutes of Health(NIH)DK 47060.A.M.group holds the Quality Mention from the Generalitat de Catalunya(2017 SGR).