Deng Cheng-Cheng, Xu Xue-Yan, Zhang Yan, Liu Long-Can, Wang Xuan, Chen Jun-Yi, Yao Liu-Yi, Zhu Ding-Heng, Yang Bin
Dermatology Hospital, Southern Medical University, Guangzhou, China.
Front Immunol. 2025 Jan 13;15:1522076. doi: 10.3389/fimmu.2024.1522076. eCollection 2024.
Fibrotic skin disease represents a major global healthcare burden, characterized by fibroblast hyperproliferation and excessive accumulation of extracellular matrix components. The immune cells are postulated to exert a pivotal role in the development of fibrotic skin disease. Single-cell RNA sequencing has been used to explore the composition and functionality of immune cells present in fibrotic skin diseases. However, these studies detected the gene expression of all cells in fibrotic skin diseases and did not enrich immune cells. Thus, the precise immune cell atlas in fibrotic skin diseases remains unknown. In this study, we plan to investigate the intricate cellular landscape of immune cells in keloid, a paradigm of fibrotic skin diseases.
CD45 immune cells were enriched by fluorescence-activated cell sorting. Single-cell RNA sequencing was used to analyze the cellular landscape of immune cells in keloid and normal scar tissues. Ki-67 staining, a scratch experiment, real-time PCR, and Western blotting were used to explore the effect of the Th17 cell supernatant on keloid fibroblasts.
Our findings revealed the intricate cellular landscape of immune cells in fibrotic skin diseases. We found that the percentage of Th17 cells was significantly increased in keloids compared to normal scars. All the subclusters of macrophages and dendritic cells (DCs) showed similar proportions between keloid samples and normal scar samples. However, upregulated genes in keloid M1 macrophages, M2 macrophages, and cDC2 are associated with the MHC class II protein complex assembly and antigen assembly, indicating that macrophages and cDC2 are active in keloids. Functional studies suggested that the supernatant of Th17 cells could promote proliferation, collagen expression, and migration of keloid fibroblasts through interleukin 17A. Importantly, increased Th17 cells are also found in other fibrotic skin diseases, such as hypertrophic scars and scleroderma, suggesting this represents a broad mechanism for skin fibrosis.
In summary, we built a single-cell atlas of fibrotic skin diseases in this study. In addition, we explored the function of Th17 cell-fibroblast interaction in skin fibrosis. These findings will help to understand fibrotic skin disease pathogenesis in depth and identify potential targets for fibrotic skin disease treatment.
纤维化皮肤病是一项重大的全球医疗负担，其特征为成纤维细胞过度增殖以及细胞外基质成分的过度积累。据推测，免疫细胞在纤维化皮肤病的发展中发挥着关键作用。单细胞RNA测序已被用于探索纤维化皮肤病中存在的免疫细胞的组成和功能。然而，这些研究检测了纤维化皮肤病中所有细胞的基因表达，并未富集免疫细胞。因此，纤维化皮肤病中精确的免疫细胞图谱仍然未知。在本研究中，我们计划研究瘢痕疙瘩（一种纤维化皮肤病范例）中免疫细胞复杂的细胞图谱。
通过荧光激活细胞分选富集CD45免疫细胞。采用单细胞RNA测序分析瘢痕疙瘩和正常瘢痕组织中免疫细胞的细胞图谱。使用Ki-67染色、划痕实验、实时PCR和蛋白质免疫印迹法来探究Th17细胞上清液对瘢痕疙瘩成纤维细胞的影响。
我们的研究结果揭示了纤维化皮肤病中免疫细胞复杂的细胞图谱。我们发现，与正常瘢痕相比，瘢痕疙瘩中Th17细胞的百分比显著增加。巨噬细胞和树突状细胞（DC）的所有亚群在瘢痕疙瘩样本和正常瘢痕样本之间显示出相似的比例。然而，瘢痕疙瘩M1巨噬细胞、M2巨噬细胞和cDC2中上调的基因与MHC II类蛋白复合物组装和抗原组装相关，表明巨噬细胞和cDC2在瘢痕疙瘩中具有活性。功能研究表明，Th17细胞的上清液可通过白细胞介素17A促进瘢痕疙瘩成纤维细胞的增殖、胶原蛋白表达和迁移。重要的是，在其他纤维化皮肤病（如增生性瘢痕和硬皮病）中也发现Th17细胞增加，这表明这代表了皮肤纤维化的一种广泛机制。
总之，我们在本研究中构建了纤维化皮肤病的单细胞图谱。此外，我们探索了Th17细胞与成纤维细胞相互作用在皮肤纤维化中的功能。这些发现将有助于深入了解纤维化皮肤病的发病机制，并确定纤维化皮肤病治疗的潜在靶点。
