The NRF2-heme oxygenase-1 system modulates cyclosporin A-induced epithelial-mesenchymal transition and renal fibrosis.
Epithelial-mesenchymal transition (EMT) is an underlying mechanism of tissue fibrosis, generating myofibroblasts, which serve as the primary source of extracellular matrix production from tissue epithelial cells. Recently, EMT has been implicated in immunosuppressive cyclosporin A (CsA)-induced renal fibrosis. In this study, the potential role of NRF2, which is the master regulator of genes associated with the cellular antioxidant defense system, in CsA-induced EMT renal fibrosis has been investigated. Pretreatment of rat tubular epithelial NRK-52E cells with sulforaphane, an activator of NRF2, could prevent EMT gene changes such as the loss of E-cadherin and the increase in alpha-smooth muscle actin (alpha-SMA) expression. Conversely, genetic inhibition of NRF2 in these cells aggravated changes in CsA-induced EMT markers. These in vitro observations could be confirmed in vivo: CsA treatment resulted in severe renal damage and fibrosis with increased expression of alpha-SMA in NRF2-deficient mice compared to wild-type mice. NRF2-mediated amelioration of CsA-caused EMT changes could be accounted for in part by the regulation of heme oxygenase-1 (HO-1). CsA treatment increased HO-1 expression in an NRF2-dependent manner in NRK cells as well as in murine fibroblasts. Induction of HO-1 by CsA seems to be advantageous in that it counteracts EMT gene changes: specific increase in HO-1 expression caused by cobalt protoporphyrin prevented CsA-mediated alpha-SMA induction, whereas genetic inhibition of HO-1 by siRNA substantially enhanced alpha-SMA induction compared to control cells. Collectively, our results suggest that the NRF2-HO-1 system plays a protective role against CsA-induced renal fibrosis by modulating EMT gene changes.
Shin
Dong-ha
DH
College of Pharmacy, Yeungnam University, Gyeongsan-si, Gyeongsangbuk-do 712-749, South Korea.
Park
Hyun-Min
HM
Jung
Kyeong-Ah
KA
Choi
Han-Gon
HG
Kim
Jung-Ae
JA
Kim
Dae-Duk
DD
Kim
Sang Geon
SG
Kang
Keon Wook
KW
Ku
Sae Kwang
SK
Kensler
Thomas W
TW
Kwak
Mi-Kyoung
MK
D000818:Animals; D016572:Cyclosporine / Q000494:pharmacology*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D005355:Fibrosis; D051547:Heme Oxygenase-1 / Q000378:metabolism*; D017879:Isothiocyanates; D007668:Kidney / Q000473:pathology*; D008297:Male; D008648:Mesoderm / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008813:Mice, Inbred ICR; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D051381:Rats; D013454:Sulfoxides; D013861:Thiocyanates / Q000494:pharmacology
D017879:Isothiocyanates; D051267:NF-E2-Related Factor 2; C495637:Nfe2l2 protein, rat; D013454:Sulfoxides; D013861:Thiocyanates; D016572:Cyclosporine; D051547:Heme Oxygenase-1; C016766:sulforaphane