Experimental hematology最新文献_第7页

3021 – EX VIVO EXPANSION OF HEMATOPOIETIC PROGENITOR CELLS DERIVED FROM INDUCED PLURIPOTENT STEM CELLS 3021 -诱导多能干细胞衍生的造血祖细胞的体外扩增

IF 2.1 4区医学 Q2 HEMATOLOGY

Experimental hematology

Pub Date : 2025-11-01 DOI: 10.1016/j.exphem.2025.104962

Edurne Solabarrieta Larrañaga , Helena Kooi , Liza Dijkhuis , Eszter Varga , Emile van den Akker , Adam Wilkinson , Gerald de Haan , Arthur Svendsen

Over the last decades, novel knowledge and technology advancements have positioned gene therapy as a pivotal resource for next-generation cell therapies. Different monogenic disorders, such as sickle cell anemia, can now be cured by autologous transplantation of ex vivo genetically engineered hematopoietic stem cells (HSC). However, patients carrying disorders leading to impaired hematopoiesis might face challenges in mobilizing enough HSCs for ex vivo gene editing, which limits this procedure. As a novel solution, recent studies have focused on generating HSCs from human-induced pluripotent stem cells (hiPSC) as an alternative source of donor HSCs.

We aimed to recapitulate de novo HSC generation in vitro using a recently established, minimal-cytokine input hiPSC-derived 3D differentiation model that spontaneously organizes into hematopoietic organoids (HeO). We observed the emergence of an early hematopoietic stem and progenitor cell (HSPC)-like population characterized by CD34 and CD43 expression and transcriptionally resembling nascent HSCs. Further functional characterization of these hiPSC-derived HSPCs (iHSPCs) confirmed their potential to differentiate into different hematopoietic lineages. Next, we tested the expansion potential of these iHSPCs using a defined, polymer-based culture condition that has been proven to support human HSPC expansion. Preliminary data indicate that there is a decrease in absolute cell number, but the CD34+CD43+ cells are preserved after 7-day culture, potentially indicating an enrichment of undifferentiated HSPCs.

These findings represent a step forward in improving in vitro iPSC-derived HSC generation and potentially upscaling. Although deriving HSCs from iPSCs is a promising solution to the scarcity of HSCs, achieving sufficient cell numbers remains a challenge. Tackling this limitation could unveil numerous clinical applications.

在过去的几十年里，新知识和技术的进步使基因治疗成为下一代细胞治疗的关键资源。不同的单基因疾病，如镰状细胞性贫血，现在可以通过体外基因工程造血干细胞（HSC）的自体移植来治愈。然而，患有导致造血功能受损的疾病的患者可能面临动员足够的造血干细胞进行体外基因编辑的挑战，这限制了这一过程。作为一种新的解决方案，最近的研究集中在从人诱导多能干细胞（hiPSC）中生成造血干细胞，作为供体造血干细胞的替代来源。我们的目标是利用最近建立的、最小细胞因子输入的hipsc衍生的3D分化模型来概括体外新生HSC的生成，该模型可以自发地组织成造血类器官（HeO）。我们观察到早期造血干细胞和祖细胞（HSPC）样群体的出现，其特征是CD34和CD43的表达，转录类似于新生造血干细胞。这些hipsc衍生的造血干细胞（iHSPCs）的进一步功能表征证实了它们分化为不同造血谱系的潜力。接下来，我们测试了这些ihspc的扩增潜力，使用一种已被证明支持人类HSPC扩增的聚合物培养条件。初步数据显示细胞绝对数量减少，但CD34+CD43+细胞在培养7天后保存完好，可能表明未分化的HSPCs富集。这些发现代表着在体外ipsc衍生的HSC生成和潜在升级方面向前迈进了一步。虽然从多能干细胞中获得造血干细胞是解决造血干细胞稀缺问题的一个有希望的解决方案，但获得足够的细胞数量仍然是一个挑战。解决这一限制可以揭示许多临床应用。

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引用次数: 0

3013 – BONE MARROW IMAGING REVEALS THE MIGRATION DYNAMICS OF NEONATAL HEMATOPOIETIC STEM CELLS 3013 -骨髓显像揭示新生儿造血干细胞的迁移动态

IF 2.1 4区医学 Q2 HEMATOLOGY

Experimental hematology

Pub Date : 2025-11-01 DOI: 10.1016/j.exphem.2025.104954

Hidenobu Mizuno , Yuji Takihara , Takumi Higaki , Tomomasa Yokomizo , Terumasa Umemoto , Kazunori Ariyoshi , Michihiro Hashimoto , Maiko Sezaki , Hitoshi Takizawa , Toshihiro Inoue , Toshio Suda

Hematopoietic stem cells (HSCs) are produced from the blood vessel walls and circulate in the blood during the perinatal period. However, the migration dynamics of how HSCs enter the bone marrow remain elusive. To observe the dynamics of HSCs over time, the present study develops an intravital imaging method to visualize bone marrow in neonatal long bones formed by endochondral ossification, which is essential for HSC niche formation. Endogenous HSCs are labeled with tdTomato under the control of an HSC marker gene, Hlf, and a customized imaging system with a bone-penetrating laser is developed for intravital imaging of tdTomato-labeled neonatal HSCs in an undrilled tibia, which is essential to avoid bleeding from fragile neonatal tibia by bone drilling. The migration speed of neonatal HSCs is higher than that of adult HSCs. Neonatal HSCs migrate from outside to inside the tibia via the blood vessels that penetrate the bone, which is a transient structure during the neonatal period, and settle on the blood vessel wall in the bone marrow. The results obtained from direct observations in vivo reveal the motile dynamics and colonization process of neonatal HSCs during bone marrow formation.

造血干细胞（hsc）由血管壁产生，在围产期在血液中循环。然而，造血干细胞如何进入骨髓的迁移动力学仍然是难以捉摸的。为了观察造血干细胞随时间的动态变化，本研究开发了一种活体成像方法来观察由软骨内成骨形成的新生儿长骨中的骨髓，这对造血干细胞生态位的形成至关重要。内源性HSC在HSC标记基因Hlf的控制下被tdTomato标记，并开发了一种定制的骨穿透激光成像系统，用于在未钻孔胫骨中对tdTomato标记的新生儿HSC进行活体成像，这对于避免骨钻孔导致脆弱的新生儿胫骨出血至关重要。新生儿造血干细胞的迁移速度高于成人造血干细胞。新生儿造血干细胞通过穿透骨骼的血管（这是新生儿时期的一种暂时性结构）从胫骨外部迁移到胫骨内部，并在骨髓血管壁上定居。直接在体内观察的结果揭示了新生儿造血干细胞在骨髓形成过程中的运动动力学和定植过程。

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引用次数: 0

2023 – HEMATOPOIETIC STEM CELLS UNDERGO BIDIRECTIONAL FATE TRANSITIONS IN VIVO 2023 -造血干细胞在体内经历双向命运转变

IF 2.1 4区医学 Q2 HEMATOLOGY

Experimental hematology

Pub Date : 2025-11-01 DOI: 10.1016/j.exphem.2025.104936

Tsuyoshi Fukushima , Trine Kristiansen , Lai Ping Wong , Yosuke Tanaka , Satoshi Yamazaki , Ruslan Sadreyev , David Scadden

Transitions between subsets of differentiating hematopoietic cells are widely regarded as unidirectional in vivo. Here, we introduced a clonal phylogenetic tracer (CP-tracer) that sequentially tags cells with genetic barcodes, enabling high-resolution analysis of ∼100,000 subclones derived from ∼400 individual hematopoietic stem cells (HSC). Using this approach, we uncovered previously uncharacterized functional subsets, including B-biased multipotent progenitors (B-MPPs) within immunophenotypic HSC. Unexpectedly, we also identified bidirectional fate transitions between myeloid-biased hematopoietic stem cells (My-HSCs) and lineage-balanced hematopoietic stem cells (balanced-HSCs). Contrary to the prevailing view that the more self-renewing My-HSCs unidirectionally transition to balanced-HSCs, phylogenetic tracing reveals that less self-renewing balanced-HSCs can also revert to My-HSCs, with the transition favoring My-HSC accumulation over time. This plasticity persists through serial transplantation, demonstrating durable lineage reprogramming. Further, balanced-HSCs contribute to mature blood cell lineages through two distinct intermediates—My-HSCs and lymphoid-biased HSCs (Ly-HSCs)—with lymphoid competence here shown to be dependent on the homeobox gene, Hhex. Hhex enables Ly-HSC differentiation, but its expression declines with age. Our findings reveal unanticipated hematopoietic stem cell plasticity and establish Hhex as a molecular determinant of myeloid-lymphoid balance.

在体内，分化的造血细胞亚群之间的过渡被广泛认为是单向的。在这里，我们引入了一种克隆系统发育示踪剂（cp示踪剂），该示踪剂用遗传条形码顺序标记细胞，能够对来自~ 400个单个造血干细胞（HSC）的~ 100,000个亚克隆进行高分辨率分析。使用这种方法，我们发现了以前未表征的功能亚群，包括免疫表型HSC中的b偏向多能祖细胞（b - mpp）。出乎意料的是，我们还发现了骨髓偏向性造血干细胞（my - hsc）和谱系平衡型造血干细胞（balanced- hsc）之间的双向命运转变。与普遍观点相反，更多的自我更新的My-HSC单向转变为平衡- hsc，系统发育追踪显示，较少的自我更新的平衡- hsc也可以恢复为My-HSC，随着时间的推移，这种转变有利于My-HSC的积累。这种可塑性通过序列移植持续存在，证明了持久的谱系重编程。此外，平衡型造血干细胞通过两种不同的中间体——my - hsc和淋巴细胞偏倚型造血干细胞（ly - hsc）——促进成熟的血细胞谱系，淋巴细胞能力在这里被证明依赖于同源盒基因Hhex。Hhex使Ly-HSC分化，但其表达随年龄增长而下降。我们的研究结果揭示了意想不到的造血干细胞可塑性，并确立了Hhex作为髓淋巴平衡的分子决定因素。

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引用次数: 0

3002 – INTEGRATION OF CRISPR-CAS9 SCREENS AND MULTI-OMICS PROFILING REVEALS CHD7-ANGPT1 AS A NOVEL MULTIDRUG RESISTANCE AXIS IN AML 3002 - crispr-cas9筛选和多组学分析的整合揭示了chd7-angpt1是aml中新的多药耐药轴

IF 2.1 4区医学 Q2 HEMATOLOGY

Experimental hematology

Pub Date : 2025-11-01 DOI: 10.1016/j.exphem.2025.104942

Mingming Niu , Hong Wang , Long Shen , Dandan Yang , Yang Yang , Tingting Zhang

Acute myeloid leukemia (AML) is a devastating hematologic malignancy and one of the most prevalent forms of leukemia in adults. Despite recent advancements and approval of novel targeted therapies, drug resistance remains a formidable clinical challenge. In this study, we conducted an unbiased clustered regularly interspaced short palindromic repeats (CRISPR-Cas9) knockout screen in AML cells to uncover novel mediators of resistance to the clinically approved FMS-like tyrosine kinase 3 (FLT3) inhibitor gilteritinib. This screen identified chromodomain helicase DNA-binding protein 7 (CHD7) as a new regulator of drug resistance. Strikingly, CHD7 loss not only conferred resistance to FLT3 inhibitors but also extended resistance to a broad range of therapeutics, including venetoclax and daunorubicin (DNR). Mechanistic investigations integrating transcriptomic and proteomic data revealed that CHD7 deletion upregulates angiopoietin-1 (ANGPT1), which drives resistance by activating the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathways. Significantly, genetic knockdown of ANGPT1 or pharmacologic inhibition of its receptor, tyrosine kinase endothelial receptor 2 (TIE2), partially restored drug sensitivity in CHD7-deficient cells. Together, these findings identify the CHD7-ANGPT1 axis as a novel mechanism of multidrug resistance in AML. Preclinical studies further suggest that combining targeted therapies with TIE2 inhibitors offers a promising strategy to overcome drug resistance in AML.

急性髓性白血病（AML）是一种毁灭性的血液系统恶性肿瘤，是成人中最常见的白血病形式之一。尽管最近新的靶向治疗取得了进展和批准，但耐药性仍然是一个巨大的临床挑战。在这项研究中，我们在AML细胞中进行了一项无偏聚类规则间隔短重复序列（CRISPR-Cas9）敲除筛选，以发现对临床批准的fms样酪氨酸激酶3 （FLT3）抑制剂吉特替尼耐药的新介质。筛选发现染色质结构域解旋酶dna结合蛋白7 （CHD7）是一种新的耐药调节因子。引人注目的是，CHD7的缺失不仅赋予了对FLT3抑制剂的耐药性，而且扩大了对包括venetoclax和柔红霉素（DNR）在内的广泛治疗药物的耐药性。结合转录组学和蛋白质组学数据的机制研究显示，CHD7缺失上调血管生成素-1 (ANGPT1)，通过激活磷脂酰肌醇3-激酶/蛋白激酶B （PI3K/AKT）和丝裂原激活的蛋白激酶/细胞外信号调节激酶（MAPK/ERK）信号通路驱动耐药性。值得注意的是，基因敲低ANGPT1或药理抑制其受体酪氨酸激酶内皮受体2 (TIE2)，可以部分恢复chd7缺陷细胞的药物敏感性。总之，这些发现确定了CHD7-ANGPT1轴是AML多药耐药的新机制。临床前研究进一步表明，联合靶向治疗与TIE2抑制剂为克服AML耐药提供了一种有希望的策略。

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引用次数: 0

2014 – TGFΒ1 REGULATES LEUKEMIA STEM CELL MARKER CD123 AND INDUCES CHEMOTHERAPY RESISTANCE 2014 - tgfΒ1调控白血病干细胞标志物cd123，诱导化疗耐药

IF 2.1 4区医学 Q2 HEMATOLOGY

Experimental hematology

Pub Date : 2025-11-01 DOI: 10.1016/j.exphem.2025.104927

Sepideh Azizi Taramsary , Denis Tvorogov , Joanna Woodcock , Hossein Anani , Angel Lopez , Dan Thomas

One of the key challenges to combat chemoresistance in acute myeloid leukemia (AML) lies in the percentage of persistent leukemic stem cells (LSCs) that exhibit aberrant expression of interleukin 3 receptor (IL-3Rα; CD123) and resemble granulocyte-macrophage progenitors. Transforming growth factor β (TGF-β) is an established antiproliferative cytokine that plays a pivotal role in regulating cell cycle inhibition and quiescence, features that have been linked to LSCs.

In this study, we uncovered a novel role for TGF-β1 signaling in the regulation of the LSC marker, IL-3Rα/CD123 (∼fourfold increase), via the TβRI/II-SMAD2-SMAD4 axis in AML. Similar to the LSC phenotype, we observed prolonged exposure to TGF-β1 maintained elevated IL-3Rα expression and promoted cellular quiescence by increasing CDKN1A/p21 expression and decreasing cellular division and proliferation (threefold decrease). Interestingly, we showed that TGF-β1 conferred a survival advantage following cytarabine treatment (∼30%), whereas cytarabine alone induced robust apoptosis. Consistently, CFU assays further showed a 20-fold increase in colony numbers in cells cotreated with TGF-β1 and cytarabine, relative to cytarabine alone.

Clinically, we uncovered overactivation of the TGF-β1 canonical pathway, SMAD2, and SMAD4 in FLT3-ITD and RUNX1-mutated leukemic cells. We observed compelling evidence that FLT3-ITD hijacks the TGF-β1 pathway through inducing constitutive SMAD2 phosphorylation and increased expression of TGF-β-responsive genes (TGFB1, SMAD2, and CDKN1A), as well as IL-3Rα.

Together, these findings elucidate a novel regulatory axis by which TGF-β1 sustains LSC-like properties, including maintaining IL-3Rα upregulation, promoting quiescence, and enforcing chemoresistance. This work has significant translational implications, highlighting the TGF-β1–SMAD2/4 pathway as a potential therapeutic target to eradicate LSC in FLT3-ITD and RUNX1-mutated AML with elevated CD123 expression.

对抗急性髓系白血病（AML）化疗耐药的关键挑战之一在于表现出白细胞介素3受体（IL-3Rα; CD123）和类似粒细胞-巨噬细胞祖细胞异常表达的持续性白血病干细胞（LSCs）的百分比。转化生长因子β (TGF-β)是一种已建立的抗增殖细胞因子，在调节细胞周期抑制和静止中起关键作用，这些特征与LSCs有关。在这项研究中，我们发现TGF-β1信号在AML中通过t -β ri /II-SMAD2-SMAD4轴调控LSC标志物IL-3Rα/CD123（增加4倍）中的新作用。与LSC表型相似，我们观察到长时间暴露于TGF-β1中，通过增加CDKN1A/p21表达，减少细胞分裂和增殖（减少三倍），维持IL-3Rα表达升高，促进细胞静止。有趣的是，我们发现TGF-β1在阿糖胞苷治疗后（约30%）具有生存优势，而阿糖胞苷单独治疗可诱导强烈的细胞凋亡。与此一致的是，CFU实验进一步显示TGF-β1和阿糖胞苷共处理的细胞的菌落数量比单独处理阿糖胞苷的细胞增加了20倍。在临床上，我们发现TGF-β1典型通路、SMAD2和SMAD4在FLT3-ITD和runx1突变的白血病细胞中过度激活。我们观察到令人信服的证据，FLT3-ITD通过诱导SMAD2组成性磷酸化和TGF-β响应基因（TGFB1、SMAD2和CDKN1A）以及IL-3Rα的表达增加，劫持了TGF-β1途径。总之，这些发现阐明了一个新的调控轴，TGF-β1通过该轴维持lsc样特性，包括维持IL-3Rα上调、促进静止和加强化学耐药。这项工作具有重要的翻译意义，强调TGF -β1-SMAD2/4途径是根除FLT3-ITD和runx1突变的AML中CD123表达升高的LSC的潜在治疗靶点。

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引用次数: 0

2021 – LOCAL BONE REMODELING SHAPES HEMATOPOIETIC STEM CELL (HSC)- MACROPHAGE INTERACTIONS AND COMPARTMENTALIZED HSC EXPANSION UNDER INFLAMMATORY STRESS 2021 -局部骨重塑塑造造血干细胞(hsc)-炎症应激下巨噬细胞相互作用和区隔hsc扩张

IF 2.1 4区医学 Q2 HEMATOLOGY

Experimental hematology

Pub Date : 2025-11-01 DOI: 10.1016/j.exphem.2025.104934

Cih-Li Hong , Ryan Adapathya , Kevin Lee , Joseph Collins , Montgomery Whalen , Laura Calvi , Leonard Zon , Shu-Chi Yeh

Inflammation induces hematopoietic stem cell (HSC) expansion with compromised fitness, a culprit of hematopoietic aging. Elucidating mechanisms to maintain HSC fitness under inflammatory stress is crucial to preserve hematopoietic integrity.

Using intravital imaging and HSC reporter mice (Mds1GFP/+; Flt3Cre), we revealed distinct stages of bone turnover across marrow cavities. HSCs within a subset of marrow cavities that lack bone resorption stayed nonmotile and solitary despite stress from cyclophosphamide/G-CSF (Nature, 2020), lipopolysaccharide (LPS, 35 μg/mouse)-induced acute inflammation, and aging. Harvesting cavity-resident HSCs under image guidance, we further revealed the superior colony-formation capacity of HSCs from nonresorptive cavities both at the steady state and under inflammation. These results suggest that local bone remodeling influences the functionality of compartmentalized HSCs.

Notably, via transcriptomic analyses and in vivo tracking, marrow macrophages in resorptive (RE) cavities were found to be proinflammatory and frequently retrieve cellular cargos from HSCs, followed by incidences of HSC division. Further in vivo staining suggested surface calreticulin expression and elevation of MHC class I on HSCs, resembling the “grooming” behavior reported in zebrafish models from the Zon group (Science, 2022, 2024). Such interaction increases with LPS challenge and aging, and continues to occur predominantly in the RE cavities. Inhibiting bone resorption with zoledronic acid (1.2 μg/mouse) reduced grooming and restored HSC fitness under LPS challenge. Taken together, our findings present novel evidence of macrophage-HSC interactions in murine bone marrow that regulate HSC clonality and unveil previously unrecognized spatial heterogeneity of the HSC niche that may be targeted to intervene in hematopoietic decline under inflammatory stress.

炎症诱导造血干细胞（HSC）扩张，降低适应性，这是造血老化的罪魁祸首。阐明炎症应激下维持HSC健康的机制对于保持造血系统的完整性至关重要。通过活体成像和HSC报告小鼠（Mds1GFP/+; Flt3Cre），我们揭示了骨髓腔骨转换的不同阶段。尽管受到环磷酰胺/G-CSF （Nature, 2020）、脂多糖（LPS， 35 μg/小鼠）诱导的急性炎症和衰老的胁迫，缺乏骨吸收的骨髓腔亚群中的hsc仍保持不动和孤立。在图像引导下收集腔内居住的hsc，我们进一步揭示了稳态和炎症状态下来自非吸收性腔的hsc的优越集落形成能力。这些结果表明，局部骨重塑影响区室化hsc的功能。值得注意的是，通过转录组学分析和体内跟踪，发现吸收（RE）腔中的骨髓巨噬细胞具有促炎作用，经常从HSC中提取细胞货物，随后发生HSC分裂。进一步的体内染色表明，hsc表面钙调蛋白表达和MHC I类升高，类似于Zon组斑马鱼模型中报道的“梳理”行为（Science, 2022, 2024）。这种相互作用随着LPS的挑战和衰老而增加，并且继续主要发生在RE腔中。用唑来膦酸（1.2 μg/只）抑制骨吸收可减少修饰，恢复脂多糖刺激下HSC的适应性。综上所述，我们的研究结果提供了小鼠骨髓中巨噬细胞-HSC相互作用调节HSC克隆的新证据，并揭示了以前未被认识到的HSC生态位的空间异质性，这可能是炎症应激下干预造血功能下降的目标。

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引用次数: 0

2001 – EPCR EXPRESSION MARKS SUPER-DORMANT LYMPHOID-PRIMED CD150NEG HEMATOPOIETIC STEM CELL 2001 - epcr表达标记超休眠淋巴细胞启动cd150阴性造血干细胞

IF 2.1 4区医学 Q2 HEMATOLOGY

Experimental hematology

Pub Date : 2025-11-01 DOI: 10.1016/j.exphem.2025.104914

Dawn Lin , Santiago Cerrizuela , Enrico Frigoli , Ian Ghezzi , Isabell Guckes , Lukas Kremer , Ana Martin-Villalba , Michael Milsom , Esther Rodriguez Correa , Pia Sommerkamp , Andreas Trumpp

The first steps of adult hematopoiesis involve the transition from hematopoietic stem cells (HSC) to multipotent progenitor (MPP) populations MPP1-6. Little is known about the recently described MPP6s, which phenotypically differ from HSCs only by their lack of CD150 expression. Here, we discover that EPCR expression discriminates EPCR¬negMPP6s that closely resemble erythroid progenitors, from bona fide EPCRpos cells that possess extensive HSC features, including long-term multilineage potential, self-renewal capacity, and dormancy. We named these cells lymphoid-primed HSCs (Lp-HSC) as they tend to acquire a slightly lymphoid-biased pattern in transplantation and display a subtle, yet detectable lymphoid-primed molecular state. Lp-HSCs can self-renew, but do so to a lesser extent compared with CD150pos HSCs. Intriguingly, Lp-HSCs are inert in cell cycle activity and represent the most dormant hematopoietic population in homeostasis. These findings refine our understanding of HSC heterogeneity and suggest a complex interplay governing stem cell lineage specification, self-renewal, and dormancy.

成人造血的第一步涉及从造血干细胞（HSC）到多能祖细胞（MPP）群体MPP1-6的转变。人们对最近描述的MPP6s知之甚少，它们与造血干细胞的表型差异仅在于缺乏CD150表达。在这里，我们发现EPCR表达区分了与红系祖细胞非常相似的EPCR阴性mpp6s和具有广泛HSC特征（包括长期多系潜能、自我更新能力和休眠）的真正的EPCRpos细胞。我们将这些细胞命名为淋巴细胞引发的造血干细胞（Lp-HSC），因为它们在移植中倾向于获得轻微的淋巴细胞偏向模式，并表现出微妙的，但可检测的淋巴细胞引发的分子状态。lp - hsc可以自我更新，但与CD150pos hsc相比，其自我更新程度较低。有趣的是，低脂造血干细胞在细胞周期活动中是惰性的，代表了稳态中最休眠的造血群体。这些发现完善了我们对造血干细胞异质性的理解，并提示了控制干细胞谱系规范、自我更新和休眠的复杂相互作用。

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引用次数: 0

1027 – BIOLOGY AND THERAPEUTIC TARGETING OF COHESIN-MUTANT MYELOID MALIGNANCIES 1027 -黏结蛋白突变的髓系恶性肿瘤的生物学和治疗靶向

IF 2.1 4区医学 Q2 HEMATOLOGY

Experimental hematology

Pub Date : 2025-11-01 DOI: 10.1016/j.exphem.2025.104907

Zuzana Tothova

R-loops are three-stranded RNA-DNA structures that form during transcription. Their accumulation leading to genomic instability has been linked to cancer; however, the functional role of R-loops as drivers of tumorigenesis, including in blood cancer development, has not been established. To address this question, we used models of myelodysplastic syndrome (MDS) and acute myeloid leukemia with mutations in the cohesin gene STAG2, which we have previously reported to be associated with DNA damage accumulation. I will describe our findings that identify STAG2 loss leading to downregulation of R-loop regulators with subsequent accumulation of R-loops, R-loop-dependent DNA damage, PARP inhibitor sensitivity, and increased mutation burden. We developed a transgenic mouse model of Tet/Stag2-mutant MDS and demonstrated R-loop-dependent MDS development, which can be reversed using expression of the R-loop-specific nuclease RNase H1. Furthermore, I will present our data demonstrating that Stag2-mutant cells activate innate immunity in an R-loop-dependent manner and are sensitive to cGAS/STING modulation. I will conclude by discussing the role of R-loops as drivers of myeloid blood cancer development and highlight the potential benefits of targeting R-loops in STAG2-mutant cancers.

r环是在转录过程中形成的三链RNA-DNA结构。它们的积累导致基因组不稳定与癌症有关；然而，r环作为肿瘤发生驱动因素的功能作用，包括在血癌发展中，尚未确定。为了解决这个问题，我们使用了骨髓增生异常综合征（MDS）和急性髓系白血病的模型，这些模型具有内聚蛋白基因STAG2突变，我们之前报道过这种突变与DNA损伤积累有关。我将描述我们的发现，确定STAG2缺失导致r环调控下调，随后r环积累，r环依赖性DNA损伤，PARP抑制剂敏感性和突变负担增加。我们开发了一种Tet/ stag2突变MDS的转基因小鼠模型，并证明了r -环依赖性MDS的发展，可以通过表达r -环特异性核酸酶RNase H1来逆转。此外，我将展示我们的数据，证明stag2突变细胞以r -环依赖的方式激活先天免疫，并对cGAS/STING调节敏感。最后，我将讨论r环作为髓系血癌发展驱动因素的作用，并强调靶向r环治疗stag2突变型癌症的潜在益处。

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引用次数: 0

3032 – MAPPING VARIABILITY IN PLURIPOTENT STEM CELL-DERIVED HEMOGENIC ENDOTHELIAL CELLS USING CELLULAR INDEXING OF TRANSCRIPTOMES AND EPITOPES SEQUENCING 3032 -利用转录组和表位测序的细胞索引来定位多能干细胞来源的造血内皮细胞的变异

IF 2.1 4区医学 Q2 HEMATOLOGY

Experimental hematology

Pub Date : 2025-11-01 DOI: 10.1016/j.exphem.2025.104973

Beth Castle, Thristan Taberna, Nora Kotkas, Ross Jones, Peter Zandstra

Induced pluripotent stem cells (iPSCs) are a renewable source for the generation of blood cells in vitro. The current gold standard for production of iPSC-derived blood cells consists of a multi-day aggregate differentiation to generate hemogenic endothelium (HE), the precursor to multipotent blood progenitors. Blood lineage competence can be dictated by the HE, but we do not yet understand how that occurs and how to best identify HE that generates a given type of blood. Further, high variability in HE produced limits the ability to use this protocol for research and clinical use. Efforts commonly rely on flow cytometry to measure surface markers for staging and identifying HE phenotypes. However, despite numerous markers reported in the literature, variability in their expression and kinetics across iPSC lines and blood differentiation protocols remains a major challenge in the field. To characterize and classify HE, we performed cellular indexing of transcriptomes and epitope sequencing (CITE-seq) on iPSC-derived HE samples. To capture common forms of variability, we captured HE populations from a time course spanning arterialization to blood induction, small and large aggregates, different blood induction protocols, and two iPSC lines. The mapping of cell surface markers to transcriptomes enabled a precise understanding of what stage a marker represents and whether this is maintained across protocols and cell lines. Pseudotime mapping with gene regulatory network analysis using IQCELL allowed time-resolved mapping of changes in transcriptional networks and their correlation with surface marker profiles. Predicted lineage competence of the HE was determined by differential gene expression and mapping populations to in vivo human blood development. Ongoing efforts are focused on sorting these populations to determine endothelial to hematopoietic transition (EHT) and lineage competence.

诱导多能干细胞（iPSCs）是体外生成血细胞的可再生来源。目前生产ipsc衍生的血细胞的黄金标准包括多日的聚集分化，以产生造血内皮（HE），多能造血祖细胞的前体。血液谱系能力可以由HE决定，但我们还不知道这是如何发生的，也不知道如何最好地识别产生特定血型的HE。此外，HE产生的高度可变性限制了将该方案用于研究和临床应用的能力。努力通常依靠流式细胞术来测量表面标记物的分期和鉴定HE表型。然而，尽管文献中报道了许多标记物，但它们在iPSC系和血液分化方案中的表达和动力学的可变性仍然是该领域的主要挑战。为了对HE进行表征和分类，我们对ipsc衍生的HE样本进行了转录组的细胞索引和表位测序（CITE-seq）。为了捕捉常见的变异形式，我们从动脉化到血液诱导、小聚集体和大聚集体、不同的血液诱导方案和两个iPSC系的时间过程中捕获了HE群体。将细胞表面标记物映射到转录组，可以精确地了解标记物所代表的阶段，以及这是否在不同的方案和细胞系中保持不变。使用IQCELL进行基因调控网络分析的伪时间作图，可以对转录网络的变化及其与表面标记谱的相关性进行时间分辨作图。预测HE的谱系能力是通过差异基因表达和定位人群来确定的。正在进行的工作集中在分类这些人群，以确定内皮到造血过渡（EHT）和谱系能力。

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引用次数: 0

1016 – THE BIOLOGY AND PATHOBIOLOGY OF BONE MARROW-DERIVED FIBROCYTES 1016 -骨髓源性纤维细胞的生物学和病理学

IF 2.1 4区医学 Q2 HEMATOLOGY

Experimental hematology

Pub Date : 2025-11-01 DOI: 10.1016/j.exphem.2025.104896

Shannon Elf, William Heaton

Despite a well-characterized mutational landscape, the molecular and cellular etiology of myelofibrosis (MF) remains poorly understood. Several reports in recent years have demonstrated a crucial role for neoplastic fibrocytes in MF, with patients displaying significant expansion of this cell population in the bone marrow. The fibrocyte is a unique monocyte-derived, proinflammatory, collagen-producing cell type that has been shown to play a key role in wound healing, tissue repair, and inflammation. Fibrocytes possess features of both monocytic lineage cells and fibroblasts, but a lack of knowledge regarding definitive cell surface markers, gene expression profiles, and general function has made it a difficult cell type to study. As such, precisely how fibrocyte differentiation and expansion are regulated, what controls normal and neoplastic fibrocyte fate, and how these cells can be targeted for therapeutic gain in fibrotic diseases all remain elusive.

We have developed an in vitro human fibrocyte system in which we can differentiate primary human CD34+ hematopoietic stem and progenitor cells (HSPCs) from aged healthy donors through the monocyte lineage and into putative fibrocytes. Using this system, we have performed multiomics and single-cell sequencing studies to identify definitive cell surface markers, metabolic features, and gene expression profiles that distinguish fibrocytes from other monocytic lineage cells and fibroblasts. We have further identified unique features of neoplastic fibrocytes possessing different MF driver mutations that may explain why some myeloproliferative neoplasm (MPN) mutations are more frequent in MF than others, including differences in MHC-I cell surface presentation and immune-mediated clearance.

In sum, this study revealed new insights into the molecular mechanisms underlying the biology of normal fibrocytes and the pathobiology of MF fibrocytes, allowing us to identify novel points of therapeutic intervention that have the potential to cure MF and spare healthy cells.

尽管有一个很好的特征突变景观，髓纤维化（MF）的分子和细胞病因仍然知之甚少。近年来的几篇报道表明，肿瘤纤维细胞在MF中起着至关重要的作用，患者骨髓中显示出这种细胞群的显著扩增。纤维细胞是一种独特的单核细胞来源，促炎，胶原生成细胞类型，已被证明在伤口愈合，组织修复和炎症中发挥关键作用。纤维细胞具有单核细胞谱系细胞和成纤维细胞的特征，但缺乏关于明确的细胞表面标记、基因表达谱和一般功能的知识，使其成为一种难以研究的细胞类型。因此，纤维细胞的分化和扩张是如何被调控的，是什么控制着正常和肿瘤纤维细胞的命运，以及这些细胞如何在纤维化疾病中靶向治疗，这些都是难以捉摸的。我们已经开发了一种体外人纤维细胞系统，在该系统中，我们可以通过单核细胞谱系将来自健康老年供者的原代人CD34+造血干细胞和祖细胞（HSPCs）分化为假定的纤维细胞。使用该系统，我们进行了多组学和单细胞测序研究，以确定确定的细胞表面标记，代谢特征和基因表达谱，以区分纤维细胞与其他单核细胞谱系细胞和成纤维细胞。我们进一步确定了具有不同MF驱动突变的肿瘤纤维细胞的独特特征，这可能解释了为什么一些骨髓增生性肿瘤（MPN）突变在MF中比其他突变更频繁，包括MHC-I细胞表面呈现和免疫介导清除的差异。总之，这项研究揭示了正常纤维细胞生物学和MF纤维细胞病理生物学的分子机制的新见解，使我们能够确定新的治疗干预点，这些点有可能治愈MF并保护健康细胞。

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引用次数: 0