Department of Gastroenterology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China.
Institute of Photomedicine, Shanghai Skin Disease Hospital, School of Medicine, Tongji University, Shanghai 200443, China.
Inflamm Bowel Dis. 2023 Jun 1;29(6):850-865. doi: 10.1093/ibd/izac266.
Creeping fat (CrF) has been recognized to play a positive role in Crohn's disease (CD) progression, yet the cellular compositions within mesenteric adipose tissue (MAT) and their potential mechanism in CrF formation are poorly understood.
Analysis of 10X single-cell RNA sequencing was performed on 67 064 cells from 3 pairs of surgically resected samples of CrF and their uninvolved MAT. The results were validated in another cohort with 6 paired MAT samples by immunofluorescence.
All samples manifested excellent consistency and repeatability in our study, and 10 cell types from the transcriptome atlas, including 20 clusters, were identified. In CrF, a specific vascular endothelial cell subpopulation highly expressing lipoprotein lipase was first identified, with a significantly increased proportion. This vascular endothelial cell subpopulation manifested robust peroxisome proliferator-activated receptor γ (PPARγ) transcription activity and an upregulated PPAR signaling pathway and was involved in lipid metabolism and the antibacterial response. A novel fibroblast subpopulation (FC3) with remarkable GREM1 and RFLNB expression was identified and validated to predominantly accumulate in the CrF. The FC3 was annotated as inflammation-associated fibroblasts, which are characterized by inflammatory responses and the regulation of Smad phosphorylation related to intestinal fibrosis. The trajectory of fibroblasts revealed their pro-inflammatory and profibrotic conversion tendency during CrF formation with corresponding gene dynamics. Additionally, we unprecedently dissected the different origins and functions of 6 macrophage subclusters within the myeloid compartment.
Our results uncover the cellular heterogeneity in the MAT of CD and the role of these various cellular compositions in CrF development. This comprehensive understanding of CrF provides future directions for in-depth research on and potential targets for MAT-based treatment.
人们已经认识到“ creeping fat ”（CrF）在克罗恩病（CD）的进展中起着积极的作用，但肠系膜脂肪组织（MAT）中的细胞成分及其在 CrF 形成中的潜在机制仍知之甚少。
对 3 对手术切除的 CrF 及其未受累的 MAT 样本的 67064 个细胞进行了 10X 单细胞 RNA 测序分析。通过免疫荧光法在另一个包含 6 对 MAT 样本的队列中对结果进行了验证。
我们的研究中所有样本均表现出极好的一致性和可重复性，并从转录组图谱中鉴定出 10 种细胞类型，包括 20 个簇。在 CrF 中，首次鉴定出一个高度表达脂蛋白脂肪酶的特定血管内皮细胞亚群，其比例明显增加。这个血管内皮细胞亚群表现出强烈的过氧化物酶体增殖物激活受体 γ（PPARγ）转录活性和上调的 PPAR 信号通路，并参与脂质代谢和抗菌反应。一个新型的成纤维细胞亚群（FC3）被鉴定出来，其特征是显著表达 GREM1 和 RFLNB，并在 CrF 中大量积累。FC3 被注释为炎症相关成纤维细胞，其特征是炎症反应和与肠道纤维化相关的 Smad 磷酸化的调节。成纤维细胞的轨迹揭示了它们在 CrF 形成过程中向促炎和促纤维化转化的趋势，以及相应的基因动力学。此外，我们首次剖析了髓系细胞中 6 个巨噬细胞亚群的不同起源和功能。
我们的研究结果揭示了 CD 患者 MAT 中的细胞异质性，以及这些不同细胞成分在 CrF 发展中的作用。对 CrF 的全面认识为深入研究 MAT 为基础的治疗方法提供了未来的方向。
