Restoration of kidney tubular epithelium following sublethal injury sequentially involves partial epithelial–mesenchymal transition(pEMT),proliferation,and further redifferentiation into specialized tubule epithelial...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.展开更多
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).
文摘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.
