Dulaglutide Ameliorates Intrauterine Adhesion by Suppressing Inflammation and Epithelial-Mesenchymal Transition via Inhibiting the TGF-β/Smad2 Signaling Pathway

Intrauterine adhesion (IUA) is a common gynecological disease with limited therapeutic options. Dulaglutide is a long-acting glucagon-like peptide-1 (GLP-1) analog with some anti-fibrotic and anti-inflammatory properties; however, its action on IUA remains uncertain. The purpose of the experiments in this study was to explore the effect of dulaglutide on IUA and to elucidate its mechanism to provide new ideas for the clinical treatment of IUA. An IUA mouse model was established via mechanical curettage and inflammation induction; mice received subcutaneous injection with three doses of dulaglutide once a day for two weeks (treatment) or equal amounts of sterile ddH₂O (control), and sham-operated mice were treated similarly to the control mice. Mice were sacrificed, and uterine tissues were subjected to hematoxylin and eosin (H&E) and Masson's trichrome staining for histomorphological and pathological analyses and real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting (WB) for gene and protein expression analyses. Dulaglutide improved the shape of the uterine cavity, increased endometrial thickness and the number of glands, and significantly reduced the area of collagen fiber deposition in the endometrium. It significantly reduced collagen type I A 1 (COL1A1), interleukin-1beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), C-C motif chemokine ligand 2 (CCL2), F4/80 (macrophage), vimentin and transforming growth factor-beta (TGF-β) mRNA levels and COL1A1, IL-1β, IL-6, TNF-α, F4/80, vimentin, E-cadherin, TGF-β, and p-Smad2 protein expression levels. This study demonstrates that dulaglutide reduces inflammatory responses by inhibiting M1 macrophage polarization and inflammatory factor release and may ameliorate fibrosis by inhibiting epithelial-mesenchymal transition (EMT) via TGF-β/Smad2 signaling.

Overexpression of miR-133a-3p inhibits fibrosis and proliferation of keloid fibroblasts by regulating IRF5 to inhibit the TGF-β/Smad2 pathway

AIM

Keloid is a benign dermal tumor with excessive hyperplasia and deposition of collagen. As a common tumor suppressor gene, miR-133a-3p has not been studied in keloid. This study will delve into the specific mechanism of miR-133a-3p in keloid.

METHODS

Normal skin fibroblasts and keloid fibroblasts (KFs) were first isolated from patients' normal skin and keloid, and cells were identified by morphological observation and immunofluorescence. The expressions of miR-133a-3p and extracellular matrix (ECM)-associated markers (Collagen I, III and α smooth muscle activin) were detected by Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Cell viability and apoptosis of KFs were examined by Cell Counting Kit-8 assay, flow cytometry, and Caspase-3 colorimetry. TargetScan predicted target gene for miR-133a-3p was verified by luciferase assay, qRT-PCR and Western Blot (WB). WB was used to study protein expression of TGFBR1, phosphorylated -Smad2 (p-Smad2) and Smad2. Finally, a series of rescue experiments were performed to verify the intervention of target genes on miR-133a-3p.

RESULTS

MiR-133a-3p was lowly expressed in keloid tissue and KFs. Overexpression of miR-133a-3p inhibited the expression of ECM-associated markers, reduced KFs viability, and promoted apoptosis. It was verified that interference regulator 5 (IRF5) is miR-133a-3p target gene. The rescue experiments showed that IRF5 reversed the effect of miR-133a-3p mimic on inhibiting fibrosis, and reversed the effects on promoting apoptosis and reducing cell proliferation.

CONCLUSION

Overexpressed miR-133a-3p inhibits fibrosis by down-regulating IRF5 and thus inhibiting the TGF-β/Smad2 pathway. And it also promotes KFs apoptosis and reduces proliferation.

Glabridin inhibits the activation of myofibroblasts in human fibrotic buccal mucosal fibroblasts through TGF-β/smad signaling

Oral submucous fibrosis (OSF) has been recognized as one of the oral potentially malignant disorders. Areca nut chewing is implicated in this pathological fibrosis, and it causes chronic inflammation and persistent activation of myofibroblasts. As yet, existing treatments only provide temporary symptomatic relief and there is a lack of an effective intervention to cure OSF. Therefore, development of approaches to ameliorate myofibroblast activities becomes a crucial objective to prevent the malignant progression of OSF. In this study, we examined the inhibitory effect of glabridin, an isoflavane extracted from licorice root, on the myofibroblast characteristics in human fibrotic buccal mucosal fibroblasts (fBMFs). Our results showed that myofibroblast activities, including collagen gel contractility, migration, invasion and wound healing abilities were reduced after exposure of glabridin in a dose-dependent manner. Most importantly, we demonstrated that the arecoline-induced myofiroblast activities were abolished by glabridin treatment. Additionally, the expression of the myofibroblast marker α-smooth muscle actin and other fibrogenic marker, type I collagen, in fBMFs were dose-dependently downregulated. Moreover, we showed that the production of TGF-β was suppressed by glabridin in fBMFs and the protein expression of phospho-Smad2 was decreased as well. In summary, our data suggested that glabridin repressed the myofibroblast features in fBMFs via TGF-β/Smad2 signaling pathway. Glabridin also prevented the arecoline-increased myofibroblast activities, and could serve as a natural anti-fibrosis compound for OSF.