Engraftment of human hematopoietic stem cells is more efficient in female NOD/SCID/IL-2Rgc-null recipients

Abstract Repopulation of immunodeficient mice remains the primary method to assay human hematopoietic stem cells (HSCs). Here we report that female NOD/SCID/IL-2Rgc-null mice are far superior in detecting human HSCs (Lin−CD34+CD38−CD90+CD45RA−) compared with male recipients. When multiple HSCs were transplanted, female recipients displayed a trend (1.4-fold) toward higher levels of human chimerism (female vs male: injected femur, 44.4 ± 9.3 vs 32.2 ± 6.2; n = 12 females, n = 24 males; P = .1). Strikingly, this effect was dramatically amplified at limiting cell doses where female recipients had an approximately 11-fold higher chimerism from single HSCs (female vs male: injected femur, 8.1 ± 2.7 vs 0.7 ± 0.7; n = 28 females, n = 20 males; P < .001). Secondary transplantations from primary recipients indicate that females more efficiently support the self-renewal of human HSCs. Therefore, sex-associated factors play a pivotal role in the survival, proliferation, and self-renewal of human HSCs in the xenograft model, and recipient sex must be carefully monitored in the future design of experiments requiring human HSC assays.

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Accumulation of oxidative DNA damage restricts the self-renewal capacity of human hematopoietic stem cells

Blood ◽

10.1182/blood-2011-01-330050 ◽

2011 ◽

Vol 118 (11) ◽

pp. 2941-2950 ◽

Cited By ~ 187

Author(s):

Takashi Yahata ◽

Tomomi Takanashi ◽

Yukari Muguruma ◽

Abd Aziz Ibrahim ◽

Hideyuki Matsuzawa ◽

...

Keyword(s):

Stem Cells ◽

Dna Damage ◽

Hematopoietic Stem Cells ◽

Oxidative Dna Damage ◽

Major Influence ◽

Glutathione Synthetase ◽

Causative Role ◽

Hematopoietic Stem ◽

Immunodeficient Mice ◽

Human Hscs

Abstract Stem cells of highly regenerative organs including blood are susceptible to endogenous DNA damage caused by both intrinsic and extrinsic stress. Response mechanisms to such stress equipped in hematopoietic stem cells (HSCs) are crucial in sustaining hematopoietic homeostasis but remain largely unknown. In this study, we demonstrate that serial transplantation of human HSCs into immunodeficient mice triggers replication stress that induces incremental elevation of intracellular reactive oxygen species (ROS) levels and the accumulation of persistent DNA damage within the human HSCs. This accumulation of DNA damage is also detected in HSCs of clinical HSC transplant patients and elderly individuals. A forced increase of intracellular levels of ROS by treatment with a glutathione synthetase inhibitor aggravates the extent of DNA damage, resulting in the functional impairment of HSCs in vivo. The oxidative DNA damage activates the expression of cell-cycle inhibitors in a HSC specific manner, leading to the premature senescence among HSCs, and ultimately to the loss of stem cell function. Importantly, treatment with an antioxidant can antagonize the oxidative DNA damage and eventual HSC dysfunction. The study reveals that ROS play a causative role for DNA damage and the regulation of ROS have a major influence on human HSC aging.

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Highly potent human hematopoietic stem cells first emerge in the intraembryonic aorta-gonad-mesonephros region

Journal of Experimental Medicine ◽

10.1084/jem.20111688 ◽

2011 ◽

Vol 208 (12) ◽

pp. 2417-2427 ◽

Cited By ~ 120

Author(s):

Andrejs Ivanovs ◽

Stanislav Rybtsov ◽

Lindsey Welch ◽

Richard A. Anderson ◽

Marc L. Turner ◽

...

Keyword(s):

Stem Cells ◽

Hematopoietic Stem Cells ◽

Hematopoietic Stem ◽

Immunodeficient Mice ◽

Adult Organism ◽

Human Hscs ◽

High Level ◽

Very High

Hematopoietic stem cells (HSCs) emerge during embryogenesis and maintain hematopoiesis in the adult organism. Little is known about the embryonic development of human HSCs. We demonstrate that human HSCs emerge first in the aorta-gonad-mesonephros (AGM) region, specifically in the dorsal aorta, and only later appear in the yolk sac, liver, and placenta. AGM region cells transplanted into immunodeficient mice provide long-term high level multilineage hematopoietic repopulation. Human AGM region HSCs, although present in low numbers, exhibit a very high self-renewal potential. A single HSC derived from the AGM region generates at least 300 daughter HSCs in primary recipients, which disseminate throughout the entire recipient bone marrow and are retransplantable. These findings highlight the vast regenerative potential of the earliest human HSCs and set a new standard for in vitro generation of HSCs from pluripotent stem cells for the purpose of regenerative medicine.

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Using mitochondrial activity to select for potent human hematopoietic stem cells

Blood Advances ◽

10.1182/bloodadvances.2020003658 ◽

2021 ◽

Vol 5 (6) ◽

pp. 1605-1616

Author(s):

Jiajing Qiu ◽

Jana Gjini ◽

Tasleem Arif ◽

Kateri Moore ◽

Miao Lin ◽

...

Keyword(s):

Stem Cells ◽

Hematopoietic Stem Cells ◽

Hematopoietic Cell Transplantation ◽

Mitochondrial Activity ◽

Mitochondrial Morphology ◽

Blood Disorders ◽

Hematopoietic Stem ◽

Immunodeficient Mice ◽

Human Hscs

Abstract Hematopoietic cell transplantation is a critical curative approach for many blood disorders. However, obtaining grafts with sufficient numbers of hematopoietic stem cells (HSCs) that maintain long-term engraftment remains challenging; this is due partly to metabolic modulations that restrict the potency of HSCs outside of their native environment. To address this, we focused on mitochondria. We found that human HSCs are heterogeneous in their mitochondrial activity as measured by mitochondrial membrane potential (MMP) even within the highly purified CD34+CD38−CD45RA−CD90+CD49f+ HSC population. We further found that the most potent HSCs exhibit the lowest mitochondrial activity in the population. We showed that the frequency of long-term culture initiating cells in MMP-low is significantly greater than in MMP-high CD34+CD38−CD45RA−CD90+ (CD90+) HSCs. Notably, these 2 populations were distinct in their long-term repopulating capacity when transplanted into immunodeficient mice. The level of chimerism 7 months posttransplantation was >50-fold higher in the blood of MMP-low relative to MMP-high CD90+ HSC recipients. Although more than 90% of both HSC subsets were in G0, MMP-low CD90+ HSCs exhibited delayed cell-cycle priming profile relative to MMP-high HSCs. These functional differences were associated with distinct mitochondrial morphology; MMP-low in contrast to MMP-high HSCs contained fragmented mitochondria. Our findings suggest that the lowest MMP level selects for the most potent, likely dormant, stem cells within the highly purified HSC population. These results identify a new approach for isolating highly potent human HSCs for further clinical applications. They also implicate mitochondria in the intrinsic regulation of human HSC quiescence and potency.

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Clonal analysis of thymus-repopulating cells presents direct evidence for self-renewal division of human hematopoietic stem cells

Blood ◽

10.1182/blood-2006-02-002204 ◽

2006 ◽

Vol 108 (7) ◽

pp. 2446-2454 ◽

Cited By ~ 11

Author(s):

Takashi Yahata ◽

Shizu Yumino ◽

Yin Seng ◽

Hiroko Miyatake ◽

Tomoko Uno ◽

...

Keyword(s):

Stem Cells ◽

Hematopoietic Stem Cells ◽

Clonal Analysis ◽

Self Renewal ◽

Hematopoietic Stem ◽

Immunodeficient Mice ◽

Integration Sites ◽

Polymerase Chain ◽

Kinetics Of

Abstract To elucidate the in vivo kinetics of human hematopoietic stem cells (HSCs), CD34+CD38– cells were infected with lentivirus vector and transplanted into immunodeficient mice. We analyzed the multilineage differentiation and self-renewal abilities of individual thymus-repopulating clones in primary recipients, and their descending clones in paired secondary recipients, by tracing lentivirus gene integration sites in each lymphomyeloid progeny using a linear amplification-mediated polymerase chain reaction (PCR) strategy. Our clonal analysis revealed that a single human thymus-repopulating cell had the ability to produce lymphoid and myeloid lineage cells in the primary recipient and each secondary recipient, indicating that individual human HSCs expand clonally by self-renewal division. Furthermore, we found that the proportion of HSC clones present in the CD34+ cell population decreased as HSCs replicated during extensive repopulation and also as the differentiation capacity of the HSC clones became limited. This indicates the restriction of the ability of individual HSCs despite the expansion of total HSC population. We also demonstrated that the extensive self-renewal potential was confined in the relatively small proportion of HSC clones. We conclude that our clonal tracking studies clearly demonstrated that heterogeneity in the self-renewal capacity of HSC clones underlies the differences in clonal longevity in the CD34+ stem cell pool.

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