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Updated: May 19, 2026
In Vitro SUMOylation Assay to Study SUMO E3 Ligase Activity
Published on: January 29, 2018
Inhibition of sumoylation prevents experimental fibrosis
Aisa Khodzhigorova1, Alfiya Distler, Veronika Lang
1Department of Internal Medicine III and Institute for Clinical Immunology, University of Erlangen-Nuremberg, Erlangen, Germany.
Objectives:
Fibrosis is a predominant cause of death in systemic sclerosis (SSc). First epigenetic modifications have recently been shown to contribute to activation of SSc fibroblasts. Here, we investigated inhibition of sumoylation as a novel antifibrotic approach.
Methods:
Sumoylation was inhibited by siRNA-mediated knockdown of the Small Ubiquitin-like MOdifiers (SUMO) E2-conjugating enzyme Ubc9, which is essential for sumoylation. The effects of knockdown of Ubc9 were analysed in bleomycin-induced dermal fibrosis, and in the model of fibrosis induced by overexpression of a constitutively active TGF-beta receptor type I (TBR). SUMO-1 and phosphorylated Smad3 were detected by immunohistochemistry.
Results:
Increased staining for SUMO-1 was detected in patients with SSc and in experimental fibrosis. Inhibition of sumoylation exerted potent antifibrotic effects and prevented dermal thickening, myofibroblast differentiation and accumulation of collagen induced by bleomycin, or by overexpression of constitutively active TBR. Moreover, knockdown of Ubc9 reduced the accumulation of phosphorylated Smad3 in experimental fibrosis indicating that inhibition of sumoylation may normalise canonical TGF-β signalling in vivo.
Conclusions:
We demonstrate that inhibition of sumoylation reduces canonical TGF-β signalling and prevents experimental fibrosis in different preclinical models. These data provide first evidence that targeting of aberrant sumoylation may be a novel therapeutic approach for fibrotic diseases.
Insights
Inhibiting sumoylation, a key epigenetic modification, effectively treats fibrosis in preclinical models. This approach reduces dermal thickening and collagen accumulation, offering a novel therapeutic strategy for fibrotic diseases.
Area of Science:
- Epigenetics
- Molecular Biology
- Fibrosis Research
Background:
- Fibrosis is a major cause of mortality in systemic sclerosis (SSc).
- Epigenetic modifications, including sumoylation, are implicated in activating SSc fibroblasts.
- Aberrant sumoylation is increasingly recognized as a contributor to fibrotic processes.
Purpose of the Study:
- To investigate the potential of inhibiting sumoylation as a novel antifibrotic therapeutic strategy.
- To explore the role of Ubc9, a crucial sumoylation enzyme, in fibrotic disease models.
- To assess the impact of sumoylation inhibition on TGF-β signaling pathways.
Main Methods:
- Sumoylation was inhibited using siRNA-mediated knockdown of Ubc9, the essential SUMO E2-conjugating enzyme.
- Effects were evaluated in bleomycin-induced dermal fibrosis and a constitutively active TGF-β receptor I (TBR) overexpression model.
- SUMO-1 and phosphorylated Smad3 levels were quantified using immunohistochemistry.
Main Results:
- Elevated SUMO-1 staining was observed in SSc patients and experimental fibrosis models.
- Inhibition of sumoylation via Ubc9 knockdown demonstrated potent antifibrotic effects, reducing dermal thickening and collagen deposition.
- Knockdown of Ubc9 decreased phosphorylated Smad3 accumulation, suggesting normalization of canonical TGF-β signaling in vivo.
Conclusions:
- Inhibition of sumoylation effectively prevents experimental fibrosis across multiple preclinical models.
- Targeting aberrant sumoylation presents a promising novel therapeutic avenue for fibrotic diseases.
- This study provides the first evidence for sumoylation inhibition as an antifibrotic strategy.
