Browsing by Author "Huang, Xinxin"

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    Activation of OCT4 enhances ex vivo expansion of human cord blood hematopoietic stem and progenitor cells by regulating HOXB4 expression
    (SpringerNature, 2016-01) Huang, Xinxin; Lee, Man-Ryul; Cooper, Scott; Hangoc, Giao; Hong, Ki-Sung; Chung, Hyung-Min; Broxmeyer, Hal E.; Department of Microbiology & Immunology, IU School of Medicine
    Although hematopoietic stem cells (HSC) are the best characterized and the most clinically used adult stem cells, efforts are still needed to understand how to best ex vivo expand these cells. Here we present our unexpected finding that OCT4 is involved in the enhancement of cytokine-induced expansion capabilities of human cord blood (CB) HSC. Activation of OCT4 by Oct4-activating compound 1 (OAC1) in CB CD34(+) cells enhanced ex vivo expansion of HSC, as determined by a rigorously defined set of markers for human HSC, and in vivo short-term and long-term repopulating ability in NSG mice. Limiting dilution analysis revealed that OAC1 treatment resulted in 3.5-fold increase in the number of SCID repopulating cells (SRCs) compared with that in day 0 uncultured CD34(+) cells and 6.3-fold increase compared with that in cells treated with control vehicle. Hematopoietic progenitor cells, as assessed by in vitro colony formation, were also enhanced. Furthermore, we showed that OAC1 treatment led to OCT4-mediated upregulation of HOXB4. Consistently, siRNA-mediated knockdown of HOXB4 expression suppressed effects of OAC1 on ex vivo expansion of HSC. Our study has identified the OCT4-HOXB4 axis in ex vivo expansion of human CB HSC.
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    Antagonism of PPARγ signaling expands human hematopoietic stem and progenitor cells by enhancing glycolysis
    (Nature Publishing group, 2018-03) Guo, Bin; Huang, Xinxin; Lee, Man Ryul; Lee, Sang A; Broxmeyer, Hal E.; Microbiology and Immunology, School of Medicine
    Hematopoietic stem cells (HSCs) quiescently reside in bone marrow niches and have the capacity to self-renew or differentiate to form all blood cells throughout the lifespan of an animal–. Allogeneic HSC transplantation is a life-saving treatment for malignant and non-malignant disorders,. HSCs isolated from umbilical cord blood (CB) are used for hematopoietic cell transplantation (HCT)–, but due to limited numbers of HSCs in single units of umbilical CB, a number of methods have been proposed for ex vivo expansion of human HSCs,,. We show here that antagonism of the nuclear hormone receptor PPARγ promotes ex vivo expansion of phenotypically and functionally-defined subsets of human CB HSCs and hematopoietic progenitor cells (HSPCs). PPARγ antagonism in CB HSPCs strongly downregulated expression of several differentiation associated genes, as well as fructose 1, 6-bisphosphatase (FBP1), a negative regulator of glycolysis, and enhanced glycolysis without compromising mitochondrial metabolism. The expansion of CB HSPCs by PPARγ antagonism was completely suppressed by removal of glucose or inhibition of glycolysis. Moreover, knockdown of FBP1 expression promoted glycolysis and ex vivo expansion of long-term repopulating CB HSPCs, whereas overexpression of FBP1 suppressed the expansion of CB HSPCs induced by PPARγ antagonism. Our study suggests the possibility for a new and simple means for metabolic reprogramming of CB HSPCs to improve the efficacy of HCT.
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    Effects of Eupalinilide E and UM171, Alone and in Combination on Cytokine Stimulated Ex-Vivo Expansion of Human Cord Blood Hematopoietic Stem Cells
    (Elsevier, 2020-09) Zhang, Jing; Huang, Xinxin; Guo, Bin; Cooper, Scott; Capitano, Maegan L.; Johnson, Trevor C.; Siegel, Dionicio R.; Broxmeyer, Hal E.; Microbiology and Immunology, School of Medicine
    Eupalinilide E was assessed for ex-vivo expansion activity on hematopoietic stem cells (HSCs) from human cord blood (CB) CD34+ cells in serum-free, SCF, TPO and FL stimulated 7 day cultures. Eupalinilide E ex-vivo enhanced phenotyped (p) HSCs and glycolysis of CD34+ cells isolated 7 days after culture as measured by extracellular acidification rate, but did not alone show enhanced NSG engrafting capability of HSCs as determined by chimerism and numbers of SCID Repopulating cells, a quantitative measure of functional human HSCs. This is another example of pHSCs not necessarily recapitulating functional activity of these cells. Lack of effect on engrafting HSCs may be due to a number of possibilities, including down regulation of CXCR4 or of the homing capacity of these treated cells. However, Eupalinilide did act in an additive to synergistic fashion with UM171 to enhance ex vivo expansion of both pHSCs, and functionally engrafting HSCs. While reasons for the disconnect between pHSC and function of HSCs with Eupalinilide E alone cultured CB CD34+ cells is yet to be determined, the data suggest possible future use of Eupalinilide and UM171 together to enhance ex vivo production of CB HSCs for clinical hematopoietic cell transplantation.
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    Enhancing human cord blood hematopoietic stem cell engraftment by targeting nuclear hormone receptors
    (Wolters Kluwer, 2018-07) Guo, Bin; Huang, Xinxin; Broxmeyer, Hal E.; Microbiology and Immunology, School of Medicine
    PURPOSE OF REVIEW: Allogeneic hematopoietic cell transplantation (HCT) is a life-saving therapy for hematological and nonhematological diseases. Cord blood is a source of transplantable hematopoietic stem cells (HSCs), but limited numbers of HSCs in single cord blood units, which may cause delayed neutrophil, platelet, and immune cell reconstitution, is a major problem for efficient transplantation. Ex-vivo expansion and enhanced homing of cord blood HSC may overcome this disadvantage and improve its long-term engraftment. Here, we discuss the role of nuclear hormone receptors signaling in human cord blood HSC engraftment. RECENT FINDINGS: Antagonizing retinoid acid receptor (RAR) signaling promotes human HSC expansion and increases myeloid cell production. Cord blood CD34 cells expanded by SR1 promotes efficient myeloid recovery after transplantation compared with control groups, and leads to successful engraftment. Short-term treatment of glucocorticoids enhances homing and long-term engraftment of human HSCs and HPCs in NSG mice. Peroxisome proliferator-activated receptor-γ (PPARγ) antagonism expands human HSCs and HPCs by preventing differentiation and enhancing glucose metabolism. These findings demonstrate that nuclear hormone receptor signaling components might be promising targets for improving human cord blood HCT. SUMMARY: Better understanding of molecular mechanisms underlying human HSC expansion and homing mediated by nuclear hormone receptor signaling pathways will facilitate enhanced HCT efficacy.
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    Glucocorticoid hormone-induced chromatin remodeling enhances human hematopoietic stem cell homing and engraftment
    (Nature Publishing Group, 2017-04) Guo, Bin; Huang, Xinxin; Cooper, Scott; Broxmeyer, Hal E.; Microbiology and Immunology, School of Medicine
    Efficient hematopoietic stem cell (HSC) homing is important for hematopoietic cell transplantation (HCT), especially when HSC numbers are limited, as in the use of cord blood (CB). In a screen of small-molecule compounds, we identified glucocorticoid (GC) hormone signaling as an activator of CXCR4 expression in human CB HSCs and hematopoietic progenitor cells (HPCs). Short-term GC pretreatment of human CB HSCs and HPCs promoted SDF-1-CXCR4-axis-mediated chemotaxis, homing, and long-term engraftment when these cells were transplanted into primary- and secondary-recipient NSG mice. Mechanistically, activated glucocorticoid receptor binds directly to a glucocorticoid response element in the CXCR4 promoter and recruits the SRC-1-p300 complex to promote H4K5 and H4K16 histone acetylation, facilitating transcription of CXCR4. These results suggest a new and readily available means to enhance the clinical efficacy of CB HCT.
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    Hypoxia Signaling Pathway in Stem Cell Regulation: Good and Evil
    (Springer Nature, 2018-06) Huang, Xinxin; Trinh, Thao; Aljoufi, Arafat; Broxmeyer, Hal E.; Microbiology and Immunology, School of Medicine
    Purpose of Review: This review summarizes the role of hypoxia and hypoxia-inducible factors (HIFs) in the regulation of stem cell biology, specifically focusing on maintenance, differentiation, and stress responses in the context of several stem cell systems. Stem cells for different lineages/tissues reside in distinct niches, and are exposed to diverse oxygen concentrations. Recent studies have revealed the importance of the hypoxia signaling pathway for stem cell functions. Recent Findings: Hypoxia and HIFs contribute to maintenance of embryonic stem cells, generation of induced pluripotent stem cells, functionality of hematopoietic stem cells, and survival of leukemia stem cells. Harvest and collection of mouse bone marrow and human cord blood cells in ambient air results in fewer hematopoietic stem cells recovered due to the phenomenon of Extra PHysiologic Oxygen Shock/Stress (EPHOSS). Summary: Oxygen is an important factor in the stem cell microenvironment. Hypoxia signaling and HIFs play important roles in modeling cellular metabolism in both stem cells and niches to regulate stem cell biology, and represent an additional dimension that allows stem cells to maintain an undifferentiated status and multilineage differentiation potential.
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    The importance of hypoxia and extra physiologic oxygen shock/stress for collection and processing of stem and progenitor cells to understand true physiology/pathology of these cells ex vivo
    (Wolters Kluwer, 2015-07) Broxmeyer, Hal E.; O'Leary, Heather A.; Huang, Xinxin; Mantel, Charlie; Department of Microbiology and Immunology, IU School of Medicine
    PURPOSE OF REVIEW: Hematopoietic stem (HSCs) and progenitor (HPCs) cells reside in a hypoxic (lowered oxygen tension) environment, in vivo. We review literature on growth of HSCs and HPCs under hypoxic and normoxic (ambient air) conditions with a focus on our recent work demonstrating the detrimental effects of collecting and processing cells in ambient air through a phenomenon termed extra physiologic oxygen shock/stress (EPHOSS), and we describe means to counteract EPHOSS for enhanced collection of HSCs. RECENT FINDINGS: Collection and processing of bone marrow and cord blood cells in ambient air cause rapid differentiation and loss of HSCs, with increases in HPCs. This apparently irreversible EPHOSS phenomenon results from increased mitochondrial reactive oxygen species, mediated by a p53-cyclophilin D-mitochondrial permeability transition pore axis, and involves hypoxia inducing factor-1α and micro-RNA 210. EPHOSS can be mitigated by collecting and processing cells in lowered (3%) oxygen, or in ambient air in the presence of, cyclosporine A which effects the mitochondrial permeability transition pore, resulting in increased HSC collections. SUMMARY: Our recent findings may be advantageous for HSC collection for hematopoietic cell transplantation, and likely for enhanced collection of other stem cell types. EPHOSS should be considered when ex-vivo cell analysis is utilized for personalized medicine, as metabolism of cells and their response to targeted drug treatment ex vivo may not mimic what occurs in vivo.
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    m6A reader suppression bolsters HSC expansion
    (Springer Nature, 2018-09) Huang, Xinxin; Broxmeyer, Hal E.; Microbiology and Immunology, School of Medicine
    Comment on Suppression of m6A reader Ythdf2 promotes hematopoietic stem cell expansion. [Cell Res. 2018]
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    miRNA regulation of Tip110 expression and self-renewal and differentiation of human CD34+ hematopoietic cells
    (Impact Journals, 2017-12-21) Liu, Ying; Huang, Xinxin; Timani, Khalid A.; Broxmeyer, Hal E.; He, Johnny J.; Microbiology and Immunology, School of Medicine
    Tip110 expression regulates hematopoiesis, but the regulatory mechanisms during hematopoiesis are not fully understood. There are a number of putative microRNA (miRNA) binding sites identified within the Tip110 3' untranslated region (3'UTR). In this study, we determined the relationship among Tip110 miRNA, Tip110 expression and self-renewal and differentiation of human CD34+ hematopoietic cells. Using a Tip110 3UTR-based reporter gene assay, 11 miRNA showed the specific activity toward the Tip110 3'UTR and down-regulated constitutive Tip110 mRNA expression. When human cord blood CD34+ cells were differentiated, Tip110 mRNA expression showed significant decreases. Concurrently, five miRNA showed significant increases, five miRNA showed significant decreases, and one miRNA remained unchanged. To further assess the roles of miRNA in Tip110 expression and self-renewal and differentiation of human CD34+ hematopoietic cells, human cord blood CD34+ cells were transduced to express the full-length Tip110 3'UTR RNA. Expression of the Tip110 3'UTR RNA led to significant increases of Tip110 mRNA, and the number of hematopoietic stem cells and progenitor cells. Taken together, these results show important roles of Tip110 miRNA in Tip110 expression control and Tip110 regulation of hematopoiesis and offer a possibility of using Tip110 miRNA or 3'UTR as a strategy to maintain human CD34+ hematopoietic cells.
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    Mitigating oxygen stress enhances aged mouse hematopoietic stem cell numbers and function
    (American Society for Clinical Investigation, 2021-01-04) Capitano, Maegan L.; Mohamad, Safa F.; Cooper, Scott; Guo, Bin; Huang, Xinxin; Gunawan, Andrea M.; Sampson, Carol; Ropa, James; Srour, Edward F.; Orschell, Christie M.; Broxmeyer, Hal E.; Microbiology and Immunology, School of Medicine
    Bone marrow (BM) hematopoietic stem cells (HSCs) become dysfunctional during aging (i.e., they are increased in number but have an overall reduction in long-term repopulation potential and increased myeloid differentiation) compared with young HSCs, suggesting limited use of old donor BM cells for hematopoietic cell transplantation (HCT). BM cells reside in an in vivo hypoxic environment yet are evaluated after collection and processing in ambient air. We detected an increase in the number of both young and aged mouse BM HSCs collected and processed in 3% O2 compared with the number of young BM HSCs collected and processed in ambient air (~21% O2). Aged BM collected and processed under hypoxic conditions demonstrated enhanced engraftment capability during competitive transplantation analysis and contained more functional HSCs as determined by limiting dilution analysis. Importantly, the myeloid-to-lymphoid differentiation ratio of aged BM collected in 3% O2 was similar to that detected in young BM collected in ambient air or hypoxic conditions, consistent with the increased number of common lymphoid progenitors following collection under hypoxia. Enhanced functional activity and differentiation of old BM collected and processed in hypoxia correlated with reduced “stress” associated with ambient air BM collection and suggests that aged BM may be better and more efficiently used for HCT if collected and processed under hypoxia so that it is never exposed to ambient air O2.