Hematopoiesis by iPSC-derived hematopoietic stem cells of aplastic anemia that escape cytotoxic T-cell attack
Hematopoiesis by iPSC-derived hematopoietic stem cells of aplastic anemia that escape cytotoxic T-cell attack
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DOI：
10.1182/bloodadvances.2017013342
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发表时间：
2018-02-27
期刊：
影响因子：
7.5
通讯作者：
Nakao, Shinji
中科院分区：
文献类型：
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作者：
Espinoza, J. Luis;Elbadry, Mahmoud I.;Nakao, Shinji
由于6号染色体短臂拷贝数中性杂合性丢失（6pLOH）或HLA等位基因突变而导致缺乏HLA I类等位基因的造血干细胞（HSCs）通常构成获得性再生障碍性贫血（AA）患者的造血，但这些缺乏HLA（-）的HSCs诱导克隆性造血的确切机制尚不清楚。为了解决这一问题，我们从一名患有HLA-B4002缺乏（B4002（-））白细胞的AA患者中产生了诱导多能干细胞（iPSC）。从患者的单核细胞建立三种不同的iPSC克隆（野生型[WT]、6pLOH（+）和B*40：02-突变体）。在各种生长因子的存在下，iPSC的三周培养产生的造血细胞占每种表型的CD 34（+）细胞的50%至70%。当将10（6）个具有3种不同基因型的iPSC衍生的CD 34（+）（iCD 34（+））细胞注射到C57 BL/6.Rag2小鼠的股骨中时，在注射后9至12周，在小鼠的骨髓、脾和外周血中检测到2.1%至7.3%的每种HLA表型的人多谱系CD 45（+）细胞，3组间人：小鼠嵌合体比率无显著差异。用WTiCD 34（+）细胞刺激患者的CD 8（+）T细胞产生能够杀死WT iCD 34（+）细胞但不能杀死B4002（-）iCD 34（+）细胞的细胞毒性T淋巴细胞（CTL）系。这些数据表明，当自体T细胞不存在且患者外周血中存在能够选择性杀死WT HSC的CTL前体时，B400（2）iCD 34（+）细胞显示出与WT iCD 34（+）细胞相似的再增殖能力。
Hematopoietic stem cells (HSCs) that lack HLA-class I alleles as a result of copy-number neutral loss of heterozygosity of the short arm of chromosome 6 (6pLOH) or HLA allelic mutations often constitute hematopoiesis in patients with acquired aplastic anemia (AA), but the precise mechanisms underlying clonal hematopoiesis induced by these HLA-lacking (HLA(-)) HSCs remain unknown. To address this issue, we generated induced pluripotent stem cells (iPSCs) from an AA patient who possessed HLA-B4002-lacking (B4002(-)) leukocytes. Three different iPSC clones (wild-type [WT], 6pLOH(+), and B*40:02-mutant) were established from the patient's monocytes. Three-week cultures of the iPSCs in the presence of various growth factors produced hematopoietic cells that make up 50% to 70% of the CD34(+) cells of each phenotype. When 10(6) iPSC-derived CD34(+) (iCD34(+)) cells with the 3 different genotypes were injected into the femoral bone of C57BL/6.Rag2 mice, 2.1% to 7.3% human multilineage CD45(+) cells of each HLA phenotype were detected in the bone marrow, spleen, and peripheral blood of the mice at 9 to 12 weeks after the injection, with no significant difference in the human: mouse chimerism ratio among the 3 groups. Stimulation of the patient's CD8(+) T cells with the WTiCD34(+) cells generated a cytotoxic T lymphocyte (CTL) line capable of killing WT iCD34(+) cells but not B4002(-)iCD34(+) cells. These data suggest that B400(2)iCD34(+) cells show a repopulating ability similar to that of WT iCD34(+) cells when autologous T cells are absent and CTL precursors capable of selectively killing WT HSCs are present in the patient's peripheral blood.