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Updated: Apr 15, 2026
Visualization and Quantification of TGFβ/BMP/SMAD Signaling under Different Fluid Shear Stress Conditions using Proximity-Ligation-Assay
Published on: September 14, 2021
TGF-β/Smad signaling in renal fibrosis
Xiao-Ming Meng1, Patrick Ming-Kuen Tang2, Jun Li1
1School of Pharmacy, Anhui Medical University Hefei, China.
Abstract:
TGF-β (transforming growth factor-β) is well identified as a central mediator in renal fibrosis. TGF-β initiates canonical and non-canonical pathways to exert multiple biological effects. Among them, Smad signaling is recognized as a major pathway of TGF-β signaling in progressive renal fibrosis. During fibrogenesis, Smad3 is highly activated, which is associated with the down-regulation of an inhibitory Smad7 via an ubiquitin E3-ligases-dependent degradation mechanism. The equilibrium shift between Smad3 and Smad7 leads to accumulation and activation of myofibroblasts, overproduction of ECM (extracellular matrix), and reduction in ECM degradation in the diseased kidney. Therefore, overexpression of Smad7 has been shown to be a therapeutic agent for renal fibrosis in various models of kidney diseases. In contrast, another downstream effecter of TGF-β/Smad signaling pathway, Smad2, exerts its renal protective role by counter-regulating the Smad3. Furthermore, recent studies demonstrated that Smad3 mediates renal fibrosis by down-regulating miR-29 and miR-200 but up-regulating miR-21 and miR-192. Thus, overexpression of miR-29 and miR-200 or down-regulation of miR-21 and miR-192 is capable of attenuating Smad3-mediated renal fibrosis in various mouse models of chronic kidney diseases (CKD). Taken together, TGF-β/Smad signaling plays an important role in renal fibrosis. Targeting TGF-β/Smad3 signaling may represent a specific and effective therapy for CKD associated with renal fibrosis.
Insights
Transforming growth factor-β (TGF-β) signaling, particularly Smad3, drives renal fibrosis by altering extracellular matrix. Targeting TGF-β/Smad3 pathways offers a promising therapeutic strategy for chronic kidney diseases.
Area of Science:
- Nephrology
- Molecular Biology
- Fibrosis Research
Background:
- Transforming growth factor-β (TGF-β) is a key mediator in renal fibrosis.
- Smad signaling pathways, especially Smad3, are critically involved in progressive kidney fibrosis.
- An imbalance between Smad3 and Smad7, influenced by ubiquitin E3-ligases, promotes fibrogenesis.
Purpose of the Study:
- To elucidate the role of TGF-β/Smad signaling in renal fibrosis.
- To investigate the therapeutic potential of modulating Smad signaling components and related microRNAs in kidney disease.
Main Methods:
- Analysis of Smad3 and Smad7 signaling dynamics during fibrogenesis.
- Examination of the impact of Smad3 on microRNA expression (miR-29, miR-200, miR-21, miR-192).
- Evaluation of therapeutic interventions targeting Smad7 overexpression and microRNA modulation in mouse models of chronic kidney disease (CKD).
Main Results:
- Smad3 activation leads to Smad7 degradation, promoting myofibroblast accumulation and extracellular matrix (ECM) overproduction.
- Smad2 acts as a counter-regulator to Smad3, suggesting a protective role.
- Smad3 mediates renal fibrosis partly by down-regulating miR-29/miR-200 and up-regulating miR-21/miR-192.
Conclusions:
- TGF-β/Smad signaling is central to the pathogenesis of renal fibrosis.
- Overexpression of Smad7 or modulation of specific microRNAs (e.g., miR-29, miR-200) can attenuate renal fibrosis.
- Targeting the TGF-β/Smad3 pathway presents a specific and effective therapeutic approach for fibrotic kidney diseases.
