Anti-fibrotic effect of 6-bromo-indirubin-3'-oxime (6-BIO) via regulation of activator protein-1 (AP-1) and specificity protein-1 (SP-1) transcription factors in kidney cells.

Abstract

PAI-1 and CTGF are overexpressed in kidney diseases and cause fibrosis of the lungs, liver, and kidneys. We used a rat model of unilateral ureteral obstruction (UUO) to investigate whether 6-BIO, a glycogen synthase kinase-3β inhibitor, attenuated fibrosis by inhibiting PAI-1 and CTGF in vivo. Additionally, TGFβ-induced cellular fibrosis was observed in vitro using the human kidney proximal tubular epithelial cells (HK-2), and rat interstitial fibroblasts (NRK49F). Expression of fibrosis-related proteins and signaling molecules such as PAI-1, CTGF, TGFβ, αSMA, SMAD, and MAPK were determined in HK-2 and NRK49F cells using immunoblotting. To identify the transcription factors that regulate the expression of PAI-1 and CTGF the promoter activities of AP-1 and SP-1 were analyzed using luciferase assays. Confocal microscopy was used to observe the co-localization of AP-1 and SP-1 to PAI-1 and CTGF. Expression of PAI-1, CTGF, TGFβ, and α-SMA increased in UUO model as well as in TGFβ-treated HK-2 and NRK49F cells. Furthermore, UUO and TGFβ treatment induced the activation of P-SMAD2/3, SMAD4, P-ERK 1/2, P-P38, and P-JNK MAPK signaling pathways. PAI-1, CTGF, AP-1 and SP-1 promoter activity increased in response to TGFβ treatment. However, treatment with 6-BIO decreased the expression of proteins and signaling pathways associated with fibrosis in UUO model as well as in TGFβ-treated HK-2 and NRK49F cells. Moreover, 6-BIO treatment attenuated the expression of PAI-1 and CTGF as well as the promoter activities of AP-1 and SP-1, thereby regulating the SMAD and MAPK signaling pathways, and subsequently exerting anti-fibrotic effects on kidney cells.

• Authors: Jung Sun Park, In Ae Jung, Hong Sang Choi, Dong-Hyun Kim, Hoon In Choi, Eun Hui Bae, Seong Kwon Ma, Soo Wan Kim
• Journal: Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie (Biomed Pharmacother) Vol. 145 Pg. 112402 (Jan 2022) ISSN: 1950-6007 [Electronic] France
• PMID: 34773763 (Publication Type: Journal Article)
• Copyright: Copyright © 2021 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

Chemical References

• 6-bromoindirubin-3'-oxime
• Enzyme Inhibitors
• Indoles
• Oximes
• Plasminogen Activator Inhibitor 1
• Sp1 Transcription Factor
• Transcription Factor AP-1
• Connective Tissue Growth Factor
• Glycogen Synthase Kinase 3 beta

Topics

• Animals
• Cell Line
• Connective Tissue Growth Factor (drug effects, genetics)
• Enzyme Inhibitors (pharmacology)
• Fibrosis
• Glycogen Synthase Kinase 3 beta (antagonists & inhibitors)
• Humans
• Indoles (pharmacology)
• Kidney Diseases (drug therapy, pathology)
• Kidney Tubules, Proximal (drug effects, pathology)
• Male
• Oximes (pharmacology)
• Plasminogen Activator Inhibitor 1 (drug effects, genetics)
• Rats
• Rats, Sprague-Dawley
• Signal Transduction (drug effects)
• Sp1 Transcription Factor (drug effects, genetics)
• Transcription Factor AP-1 (drug effects, genetics)