An in vitro model for the pro-fibrotic effects of retinoids: mechanisms of action

TY - JOUR

T1 - An in vitro model for the pro-fibrotic effects of retinoids: mechanisms of action

AU - Rankin, A. C.

AU - Hendry, B. M.

AU - Corcoran, J. P.

AU - Xu, Qihe

PY - 2013/11

Y1 - 2013/11

N2 - Background and PurposeRetinoids, including all-trans retinoic acid (tRA), have dose-dependent pro-fibrotic effects in experimental kidney diseases. To understand and eventually prevent such adverse effects, it is important to establish relevant in vitro models and unravel their mechanisms. Experimental ApproachFibrogenic effects of retinoids were assessed in NRK-49F renal fibroblasts using picro-Sirius red staining for collagens and quantified by spectrophotometric analysis of the eluted stain. Other methods included RT-qPCR, immunoassays and matrix metalloproteinase (MMP) activity assays. Key ResultsWith or without TGF-1, tRA was dose-dependently pro-fibrotic, notably increasing collagen accumulation. tRA and TGF-1 additively suppressed expression of mRNA for MMP2, 3 and 13 and suppressed MMP activity. tRA, in the presence of TGF-1, induced plasminogen activator inhibitor-1 (PAI-1) mRNA and they additively induced PAI-1 protein expression. A PAI-1 inhibitor, a pan-retinoic acid receptor (RAR) antagonist and a pan-retinoid X receptor (RXR) antagonist each partially prevented the pro-fibrotic effect of tRA. The dose-dependent pro-fibrotic effects of a pan-RXR agonist were similar to those of tRA. A pan-RAR agonist showed weaker, less dose-dependent pro-fibrotic effects and the pro-fibrotic effects of RAR and RAR-selective agonists were even smaller. An RAR-selective agonist did not affect fibrogenesis. Conclusions and ImplicationsAn in vitro model for the pro-fibrotic effects of retinoids was established in NRK-49F cells. It was associated with reduced MMP activity and increased PAI-1 expression, and was probably mediated by RXR and RAR. To avoid or antagonize the pro-fibrotic activity of tRA, further studies on RAR isotype-selective agonists and PAI-1 inhibitors might be of value.

AB - Background and PurposeRetinoids, including all-trans retinoic acid (tRA), have dose-dependent pro-fibrotic effects in experimental kidney diseases. To understand and eventually prevent such adverse effects, it is important to establish relevant in vitro models and unravel their mechanisms. Experimental ApproachFibrogenic effects of retinoids were assessed in NRK-49F renal fibroblasts using picro-Sirius red staining for collagens and quantified by spectrophotometric analysis of the eluted stain. Other methods included RT-qPCR, immunoassays and matrix metalloproteinase (MMP) activity assays. Key ResultsWith or without TGF-1, tRA was dose-dependently pro-fibrotic, notably increasing collagen accumulation. tRA and TGF-1 additively suppressed expression of mRNA for MMP2, 3 and 13 and suppressed MMP activity. tRA, in the presence of TGF-1, induced plasminogen activator inhibitor-1 (PAI-1) mRNA and they additively induced PAI-1 protein expression. A PAI-1 inhibitor, a pan-retinoic acid receptor (RAR) antagonist and a pan-retinoid X receptor (RXR) antagonist each partially prevented the pro-fibrotic effect of tRA. The dose-dependent pro-fibrotic effects of a pan-RXR agonist were similar to those of tRA. A pan-RAR agonist showed weaker, less dose-dependent pro-fibrotic effects and the pro-fibrotic effects of RAR and RAR-selective agonists were even smaller. An RAR-selective agonist did not affect fibrogenesis. Conclusions and ImplicationsAn in vitro model for the pro-fibrotic effects of retinoids was established in NRK-49F cells. It was associated with reduced MMP activity and increased PAI-1 expression, and was probably mediated by RXR and RAR. To avoid or antagonize the pro-fibrotic activity of tRA, further studies on RAR isotype-selective agonists and PAI-1 inhibitors might be of value.

KW - fibroblasts

KW - kidney

KW - fibrosis

KW - retinoic acid

KW - retinoids

KW - TGF-

KW - PAI-1

KW - MMP

KW - RAR

KW - RXR

KW - PLASMINOGEN-ACTIVATOR INHIBITOR-1

KW - MULTIPLE FACTORS CONTRIBUTE

KW - COLLAGEN GENE-EXPRESSION

KW - HUMAN LUNG FIBROBLASTS

KW - HUMAN SKIN FIBROBLASTS

KW - ACID RECEPTOR-ALPHA

KW - TTNPB RO 13-7410

KW - ALL-TRANS

KW - EXPERIMENTAL GLOMERULONEPHRITIS

KW - SYNTHETIC RETINOIDS

U2 - 10.1111/bph.12348

DO - 10.1111/bph.12348

M3 - Article

SN - 0007-1188

VL - 170

SP - 1177

EP - 1189

JO - British Journal of Pharmacology

JF - British Journal of Pharmacology

IS - 6

M1 - N/A

ER -