Du Juan, Wu Jincheng, Song Qinqin, Li Shuangru, Hong Youwang, Anwar Aizaz, Fu Quanyou, Liu Jisong
Department of Thyroid and Breast Surgery, The Third People's Hospital of Bengbu Affiliated to Bengbu Medical University, Bengbu, 233000, Anhui, China.
Department of Burn and Plastic Surgery, The Third People's Hospital of Bengbu Affiliated to Bengbu Medical University, Bengbu, 233000, Anhui, China.
J Mol Histol. 2025 May 20;56(3):161. doi: 10.1007/s10735-025-10441-3.
Scars are traces of tissue loss left behind by connective tissue overgrowth and repair. Studies in recent years have shown that mesenchymal stem cell exosomes (MSC-Exo) have the ability to inhibit and repair cutaneous scarring, but their specific role in post-breast surgery scar formation and the mechanisms behind it remain enigmatic.
Extraction and characterization of exosomes from mesenchymal stem cells (MSCs). Western Blot and RT-qPCR were used to evaluate the expression of fibrillar protein and TGF-β/Smad3 in mammary hypertrophic scar fibroblasts (MHSFs) stimulated with MSC-Exo, sh-METTL3, sh-NEAT1 and their negative controls. Construction of a mouse model of proliferative scar formation using mechanical tension and detection of fibronectin and pathway protein expression using Western Blot and RT-qPCR. Pathologic changes of mammary scarring in mice using HE staining, Masson staining and immunofluorescence.
Both in vitro and in vivo, MSC-Exo, sh-METTL3 and sh-NEAT1 were shown to decrease the expression of COL1A1, COL3A1, α-SMA, fibronectin, TGF-β, p-Smad2/Smad2, p-Smad3/Smad3, by Western Blot and RT-qPCR. In addition, improved lesions and reduced collagen deposition were observed in mice by HE and Masson assays.
In summary, our study revealed that exosomes of MSCs function through the m6A methyltransferase METTL3, which regulates the NEAT1/TGF-β/Smad3 axis to slow down the rate of scar formation after breast surgery.
瘢痕是结缔组织过度生长和修复后留下的组织缺失痕迹。近年来的研究表明，间充质干细胞外泌体（MSC-Exo）具有抑制和修复皮肤瘢痕形成的能力，但其在乳房手术后瘢痕形成中的具体作用及其背后的机制仍不清楚。
从间充质干细胞（MSCs）中提取并鉴定外泌体。使用蛋白质免疫印迹法（Westernern印迹法（Western Blot）和逆转录-定量聚合酶链反应（RT-qPCR）评估用MSC-Exo、sh-METTL3、sh-NEAT1及其阴性对照刺激的乳腺增生性瘢痕成纤维细胞（MHSFs）中纤维状蛋白和转化生长因子-β/信号转导分子Smad3（TGF-β/Smad3）的表达。使用机械张力构建小鼠增生性瘢痕形成模型，并通过蛋白质免疫印迹法和RT-qPCR检测纤连蛋白和信号通路蛋白的表达。用苏木精-伊红染色（HE染色）、Masson染色和免疫荧光法观察小鼠乳腺瘢痕的病理变化。
蛋白质免疫印迹法和RT-qPCR结果显示，在体外和体内，MSC-Exo、sh-METTL3和sh-NEAT1均能降低Ⅰ型胶原（COL1A1）、Ⅲ型胶原（COL3A1）、α-平滑肌肌动蛋白（α-SMA）、纤连蛋白、TGF-β、磷酸化Smad2/ Smad2、磷酸化Smad3/ Smad3的表达。此外，通过HE和Masson检测观察到小鼠的病变改善，胶原沉积减少。
总之，我们的研究表明，MSCs的外泌体通过m6A甲基转移酶METTL3发挥作用，该酶调节NEAT1/TGF-β/Smad3轴，从而减缓乳房手术后瘢痕形成的速度。
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