白鸟 (2023-04-29 23:16):
#paper Single-cell transcriptomics dissects hematopoietic cell destruction and T-cell engagement in aplastic anemia. Blood. 2021. 研究背景:再生障碍性贫血 (AA) 是一种T细胞介导的造血系统自身免疫性疾病,表现为造血干细胞和祖细胞 (HSPC) 的严重耗竭。异常活化的T淋巴细胞攻击自身造血干/祖细胞(HSPC)是再生障碍性贫血(AA)发病重要的机制。 研究难点:受限于技术和 HSPC 在骨髓衰竭背景下的稀疏性。AA患者骨髓残留HSPC细胞数量极少,精细剖析骨髓损伤后HSPC各组分的病理变化及T淋巴细胞免疫打击HSPC的分子机制比较困难。 样本类型:健康供体(healthy donors,n = 8)+ 非重度再生障碍性贫血患者 (non-SAA, n = 19) + 重度再生障碍性贫血患者 (SAA,  n = 4 );另加 药物处理组:免疫抑制治疗(IST)后患者 样本取样:骨髓及外周血中分选出CD34+造血干/祖细胞和CD4+/CD8+ T淋巴细胞 实验技术:STRT-Seq(高测序深度) + Smart-seq2 研究思路:不同疾病/健康组 -> 流式分选细胞 - > CD34+造血干/祖细胞和CD4+/CD8+ T淋巴细胞->单细胞测序(STRT-Seq + Smart-seq2)->定义了9类HSPC细胞亚群->基因表达和转录调控网络分析 研究结果: ① STRT-seq克服骨髓残留造血干细胞和祖细胞HSPC数量不足的限制,对AA患者的HSPC和T细胞进行分析,分别获得了2,385个HSPC和4,081个CD4+/CD8+ T细胞的单细胞转录组,定义了9类HSPCs细胞亚群,首次绘制了AA血液病理图谱,揭示了AA发病,特别是恶性转化的新机制。 ② AA中残留的HSPC在基因表达和转录调控网络中表现出谱系特异性的改变,提示存在谱系选择性造血损伤。 ③ 综合分析HSPC和T细胞的基因表达,确定了细胞类型特异性配体-受体相互作用是AA中免疫攻击的关键分子介质。 ④ 通过追踪免疫抑制治疗(IST)后的患者,发现HSPCs和T淋巴细胞的基因表达没有完全恢复到正常水平,甚至接近治疗前的状态,这可能是AA患者需要长期维持免疫抑制治疗的主要原因之一。
IF:21.000Q1 Blood, 2021-07-08. DOI: 10.1182/blood.2020008966 PMID: 33763704
Single-cell transcriptomics dissects hematopoietic cell destruction and T-cell engagement in aplastic anemia
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Abstract:
Aplastic anemia (AA) is a T cell-mediated autoimmune disorder of the hematopoietic system manifested by severe depletion of the hematopoietic stem and progenitor cells (HSPCs). Nonetheless, our understanding of the complex relationship between HSPCs and T cells is still obscure, mainly limited by techniques and the sparsity of HSPCs in the context of bone marrow failure. Here we performed single-cell transcriptome analysis of residual HSPCs and T cells to identify the molecular players from patients with AA. We observed that residual HSPCs in AA exhibited lineage-specific alterations in gene expression and transcriptional regulatory networks, indicating a selective disruption of distinct lineage-committed progenitor pools. In particular, HSPCs displayed frequently altered alternative splicing events and skewed patterns of polyadenylation in transcripts related to DNA damage and repair, suggesting a likely role in AA progression to myelodysplastic syndromes. We further identified cell type-specific ligand-receptor interactions as potential mediators for ongoing HSPCs destruction by T cells. By tracking patients after immunosuppressive therapy (IST), we showed that hematopoiesis remission was incomplete accompanied by IST insensitive interactions between HSPCs and T cells as well as sustained abnormal transcription state. These data collectively constitute the transcriptomic landscape of disrupted hematopoiesis in AA at single-cell resolution, providing new insights into the molecular interactions of engaged T cells with residual HSPCs and render novel therapeutic opportunities for AA.
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