2021,
Blood.
DOI:
10.1182/blood.2020008966
Single-cell transcriptomics dissects hematopoietic cell destruction and T-cell engagement in aplastic anemia
Caiying Zhu
, Yu Lian
, Chenchen Wang
, Peng Wu
, Xuan Li
, Yan Gao
, Sibin Fan
, Lanlan Ai
, Liwei Fang
, Hong Pan
, Tao Cheng
, Jun Shi
, Ping Zhu
Abstract:
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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2023-04-29 23:16:00
白鸟:
#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。