Related Experiment Video
Updated: Oct 14, 2025
Mechanism of Kemeng Fang's Inhibition of Podocyte Apoptosis in Rats with Membranous Nephropathy through the PI3K/AKT Signaling Pathway
Published on: August 23, 2024
Pirfenidone Attenuates Renal Tubulointerstitial Fibrosis through Inhibiting miR-21
Liangliang Bi1, Yanjie Huang1,2, Jing Li1
1Department of Pediatrics, The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, China.
Background:
Our previous studies had shown pirfenidone (PFD) not only improved tubulointerstitial fibrosis (TIF) but also inhibited the expression of microRNA-21 (miR-21) in the renal tissue of unilateral urethral obstruction (UUO) rats. This study aims to investigate whether PFD can attenuate TIF through inhibiting miR-21 in UUO rats.
Methods:
Sprague Dawley rats were divided randomly into sham-operated group, UUO group, and PFD and olmesartan (Olm) treatment groups. Samples were collected on day 14. Expression of miR-21, TGF-β1, Smad3, and Smad7 mRNA in the renal tissue was detected using real-time quantitative PCR. Immunohistochemistry was performed to assess the protein expressions of collagen III, E-cadherin, and α-SMA. Automated capillary Western blotting was used to detect the quantitative expression of TGF-β1, Smad3, p-Smad3, Smad7, collagen III, E-cadherin, and α-SMA in renal tissues. The expression of miR-21 and Smad7 mRNA and the protein levels of collagen III and α-SMA were examined in the miR-21-overexpressing cell line, NRK-52E.
Results:
Compared with the UUO group, both PFD and Olm inhibited renal tubular dilation, diffused epithelial cell degeneration and necrosis, and reduced renal interstitial edema, inflammatory cell infiltration, and collagen fiber deposition, while no significant difference between PFD group and Olm group. Informatics-based approaches identified Smad7 as a likely candidate for regulation by miR-21. Compared with the sham group, miR-21 expression was upregulated in the UUO group resulting in the downregulation of Smad7 expression due to degradation. The overexpression of miR-21 in the in vitro model downregulated Smad7 and promoted EMT and ECM accumulation. Protein levels of TGF-β1, Smad3, p-Smad3, collagen III, and α-SMA were upregulated, while E-cadherin protein was downregulated in the UUO group than in the sham group. PFD rather than Olm decreased the expression of miR-21 and increased the expression level of Smad7 mRNA and then inhibited the TGF-β1/Smad3 signaling pathway. Olm only downregulated the TGF-β1/Smad3 signaling pathway.
Conclusions:
PFD improves TIF by downregulating the expression of miR-21, then elevating Smad7, and finally inhibiting the activation of the TGF-β1/Smad3 signaling pathway in UUO rats.
Insights
Pirfenidone (PFD) reduces tubulointerstitial fibrosis (TIF) in rats by inhibiting microRNA-21 (miR-21) and activating Smad7, thereby blocking the TGF-β1/Smad3 pathway. This study confirms PFD
Area of Science:
- Nephrology
- Molecular Biology
- Pharmacology
Background:
- Previous studies indicated pirfenidone (PFD) improves tubulointerstitial fibrosis (TIF) and inhibits microRNA-21 (miR-21) in unilateral urethral obstruction (UUO) rat models.
- Tubulointerstitial fibrosis is a common pathological feature in chronic kidney diseases.
Purpose of the Study:
- To investigate the mechanism by which PFD attenuates TIF in UUO rats, specifically focusing on the role of miR-21.
- To compare the effects of PFD and olmesartan (Olm) on TIF and related molecular pathways.
Main Methods:
- Rats were subjected to UUO and treated with PFD or Olm.
- Real-time quantitative PCR and automated capillary Western blotting were used to measure miR-21, TGF-β1, Smad3, Smad7, collagen III, E-cadherin, and α-SMA expression.
- In vitro experiments with miR-21-overexpressing NRK-52E cells were conducted.
Main Results:
- PFD and Olm both ameliorated renal structural damage and fibrosis compared to the UUO group.
- PFD treatment downregulated miR-21 and upregulated Smad7, inhibiting the TGF-β1/Smad3 pathway.
- miR-21 overexpression in vitro promoted epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) accumulation.
Conclusions:
- PFD attenuates TIF in UUO rats by downregulating miR-21 and upregulating Smad7, subsequently inhibiting the TGF-β1/Smad3 signaling pathway.
- PFD offers a therapeutic strategy for TIF by targeting the miR-21/Smad7 axis.
More Related Videos
10:15Identification of the Source of Secreted Proteins in the Kidney by Brefeldin A Injection
Published on: November 10, 2021
07:01Delivery of Exogenous Artificially Synthesized miRNA Mimic to the Kidney Using Polyethylenimine Nanoparticles in Several Kidney Disease Mouse Models
Published on: May 10, 2022
