Browsing by Author "Aljoufi, Arafat"

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    A target discovery pipeline identified ILT3 as a target for immunotherapy of multiple myeloma
    (Elsevier, 2023) Di Meo, Francesco; Iyer, Anjushree; Akama, Keith; Cheng, Rujin; Yu, Christina; Cesarano, Annamaria; Kurihara, Noriyoshi; Tenshin, Hirofumi; Aljoufi, Arafat; Marino, Silvia; Soni, Rajesh K.; Roda, Julie; Sissons, James; Vu, Ly P.; Guzman, Monica; Huang, Kun; Laskowski, Tamara; Broxmeyer, Hal E.; Roodman, David G.; Perna, Fabiana; Medicine, School of Medicine
    Multiple myeloma (MM) is an incurable malignancy of plasma cells. To identify targets for MM immunotherapy, we develop an integrated pipeline based on mass spectrometry analysis of seven MM cell lines and RNA sequencing (RNA-seq) from 900+ patients. Starting from 4,000+ candidates, we identify the most highly expressed cell surface proteins. We annotate candidate protein expression in many healthy tissues and validate the expression of promising targets in 30+ patient samples with relapsed/refractory MM, as well as in primary healthy hematopoietic stem cells and T cells by flow cytometry. Six candidates (ILT3, SEMA4A, CCR1, LRRC8D, FCRL3, IL12RB1) and B cell maturation antigen (BCMA) present the most favorable profile in malignant and healthy cells. We develop a bispecific T cell engager targeting ILT3 that shows potent killing effects in vitro and decreased tumor burden and prolonged mice survival in vivo, suggesting therapeutic relevance. Our study uncovers MM-associated antigens that hold great promise for immune-based therapies of MM.
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    Age-related decline in LEPR+ hematopoietic stem cell function
    (Springer Nature, 2023) Trinh, Thao; Ropa, James; Cooper, Scott; Aljoufi, Arafat; Sinn, Anthony; Capitano, Maegan; Broxmeyer, Hal E.; Kaplan, Mark H.; Microbiology and Immunology, School of Medicine
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    Characterization of Normal and Preleukemic Hematopoietic Stem Cell Responses to Physiologic and Extra-Physiologic Oxygen Tension
    (2022-08) Aljoufi, Arafat; Kaplan, Mark H.; Zhang, Chi; Srour, Edward F.; Kapur, Reuben
    Hematopoietic stem and progenitor cells (HSCs/HPCs) transplantation is a curative treatment for a variety of hematologic and non-hematologic diseases. Successful HSC transplantation requires infusing patients with a sufficient number of long-term engrafting HSCs. As a result, research efforts have focused on optimizing the collection process. Previous work established that harvesting mouse bone marrow HSCs under low oxygen tension similar to that reported for the bone marrow niche in situ (physioxia), results in enhanced HSC recovery and function. However, collecting bone marrow cells under physioxia is not a clinically viable approach. Here, I demonstrated that the collection and processing of peripheral blood mobilized with G-CSF alone or G-CSF and Plerixafor under physioxia resulted in a greater number of phenotypically defined long-term engrafting HSCs. Using high-resolution single cell sequencing to explore the molecular programs governing HSCs under physioxia, I identified increased expression of genes involved in HSC self-renewal and maintenance. In contrast, HSCs under ambient air upregulated genes implicated in HSC differentiation, apoptosis, and inflammatory pathways. Furthermore, wild-type HSCs under physioxia revealed a significant reduction in gene expression and activity of the epigenetic modifier Tet2. Consequently, I evaluated the phenotyping, engraftment potential and gene expression of preleukemic Tet2-/- bone marrow cells under physioxia and ambient air. Unlike wild-type HSCs, Tet2-/- HSCs/HPCs were unresponsive to changes in oxygen tension. Notably, we observed similar phenotypes, functions, and self-renewal and quiescence gene expression in wild-type HSCs under physioxia and Tet2- /- HSCs under physioxia or ambient air. These findings imply that the preserved stemness and enhanced engraftment of HSCs under physioxia may in part be a result of Tet2 downregulation. Understanding the mechanisms regulating wild-type and preleukemic HSCs under physioxia will have therapeutic implications for optimizing HSC transplantation and mitigating the growth advantage of preleukemic stem cells.
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    Collection and Processing of Mobilized Mouse Peripheral Blood at Lowered Oxygen Tension Yields Enhanced Numbers of Hematopoietic Stem Cells
    (SpringerLink, 2020-10) Aljoufi, Arafat; Cooper, Scott; Broxmeyer, Hal E.; Microbiology and Immunology, School of Medicine
    Mobilized peripheral blood (mPB) hematopoietic stem (HSCs) and progenitor (HPCs) cells are primary sources for hematopoietic cell transplantation (HCT). Successful HCT requires threshold numbers of high-quality HSCs to reconstitute hematopoiesis long-term. Nevertheless, considerable percentages of patients and healthy donors fail to achieve required thresholds of HSCs with current mobilization regimens. In this present study we demonstrate that similar to mouse bone marrow (BM) and human cord blood, collection and processing of mouse Granulocyte Colony Stimulating Factor (G-CSF)-, AMD3100/Plerixafor- or G-CSF plus AMD3100/Plerixafor-mobilized HSCs in 3% O2 results in enhanced numbers of rigorously-defined phenotypic and for G-CSF - and G-CSF plus AMD3100/Plerixafor - mPB enhanced functionally-engrafting HSCs. These results may be of potential clinical utility.
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    Consequences of coronavirus infections for primitive and mature hematopoietic cells: new insights and why it matters
    (Wolters Kluwer, 2021) Ropa, James; Trinh, Thao; Aljoufi, Arafat; Broxmeyer, Hal E.; Microbiology and Immunology, School of Medicine
    Purpose of review: In recent history there have been three outbreaks of betacoronavirus infections in humans, with the most recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; causing Coronavirus disease 2019 [COVID-19]) outbreak leading to over two million deaths, with a rapidly rising death toll. Much remains unknown about host cells and tissues affected by coronavirus infections, including the hematopoietic system. Here, we discuss the recent findings examining effects that coronavirus infection or exposure has on hematopoietic cells and the clinical implications for these effects. Recent findings: Recent studies have centered on SARS-CoV-2, demonstrating that hematopoietic stem and progenitor cells and mature immune cells may be susceptible to infection and are impacted functionally by exposure to SARS-CoV-2 Spike protein. These findings have important implications regarding hematologic complications arising from COVID-19 and other coronavirus-induced disease, which we discuss here. Summary: Infection with coronaviruses sometimes leads to hematologic complications in patients, and these hematologic complications are associated with poorer prognosis. These hematologic complications may be caused by coronavirus direct infection or impact on primitive hematopoietic cells or mature immune cells, by indirect effects on these cells, or by a combination thereof. It is important to understand how hematologic complications arise in order to seek new treatments to improve patient outcomes.
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    Fate of Hematopoiesis During Aging. What Do We Really Know, and What are its Implications?
    (Springer Nature, 2020-11-03) Broxmeyer, Hal E.; Liu, Yan; Kapur, Reuben; Orschell, Christie M.; Aljoufi, Arafat; Ropa, James P.; Trinh, Thao; Burns, Sarah; Capitano, Maegan L.; Microbiology and Immunology, School of Medicine
    There is an ongoing shift in demographics such that older persons will outnumber young persons in the coming years, and with it age-associated tissue attrition and increased diseases and disorders. There has been increased information on the association of the aging process with dysregulation of hematopoietic stem (HSC) and progenitor (HPC) cells, and hematopoiesis. This review provides an extensive up-to date summary on the literature of aged hematopoiesis and HSCs placed in context of potential artifacts of the collection and processing procedure, that may not be totally representative of the status of HSCs in their in vivo bone marrow microenvironment, and what the implications of this are for understanding aged hematopoiesis. This review covers a number of interactive areas, many of which have not been adequately explored. There are still many unknowns and mechanistic insights to be elucidated to better understand effects of aging on the hematopoietic system, efforts that will take multidisciplinary approaches, and that could lead to means to ameliorate at least some of the dysregulation of HSCs and HPCs associated with the aging process.
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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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    Leptin Receptor, a Surface Marker for a Subset of Highly Engrafting Long-term Functional Hematopoietic Stem Cells
    (Springer Nature, 2021) Trinh, Thao; Ropa, James; Aljoufi, Arafat; Cooper, Scott; Sinn, Anthony; Srour, Edward F.; Broxmeyer, Hal E.; Microbiology and Immunology, School of Medicine
    The hematopoietic system is sustained by a rare population of hematopoietic stem cells (HSCs), which emerge during early embryonic development and then reside in the hypoxic niche of the adult bone marrow microenvironment. Although leptin receptor (Lepr)-expressing stromal cells are well-studied as critical regulators of murine hematopoiesis, the biological implications of Lepr expression on HSCs remain largely unexplored. We hypothesized that Lepr+HSCs are functionally different from other HSCs. Using in vitro and in vivo experimental approaches, we demonstrated that Lepr further differentiates SLAM HSCs into two distinct populations; Lepr+HSCs engrafted better than Lepr−HSCs and self-renewed more extensively as noted in secondary transplants. Molecularly, Lepr+HSCs were characterized by a proinflammatory transcriptomic profile enriched for Type-I Interferon and Interferon-gamma (IFN-γ) response pathways, which are known to be critical for the emergence of HSCs in the embryo. We conclude that although Lepr+HSCs represent a minor subset of HSCs, they are highly engrafting cells that possess embryonic-like transcriptomic characteristics, and that Lepr can serve as a reliable marker for functional long term HSCs, which may have potential clinical applicability.
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    Physioxia enhances T-cell development ex vivo from human hematopoietic stem and progenitor cells
    (Nova Science, 2020-11) Shin, Dong-Yeop; Huang, Xinxin; Gil, Chang-Hyun; Aljoufi, Arafat; Ropa, James; Broxmeyer, Hal E.; Microbiology and Immunology, School of Medicine
    Understanding physiologic T-cell development from hematopoietic stem (HSCs) and progenitor cells (HPCs) is essential for development of improved hematopoietic cell transplantation (HCT) and emerging T-cell therapies. Factors in the thymic niche, including Notch 1 receptor ligand, guide HSCs and HPCs through T-cell development in vitro. We report that physiologically relevant oxygen concentration (5% O2,physioxia), an important environmental thymic factor, promotes differentiation of cord blood CD34+ cells into progenitor T (proT) cells in serum-free and feeder-free culture system. This effect is enhanced by a potent reducing and antioxidant agent, ascorbic acid. Human CD34+ cell-derived proT cells in suspension cultures maturate into CD3+ T cells in an artificial thymic organoid (ATO) culture system more efficiently when maintained under physioxia, compared to ambient air. Low oxygen tension acts as a positive regulator of HSC commitment and HPC differentiation toward proT cells in the feeder-free culture system and for further maturation into T cells in the ATO. Culturing HSCs/HPCs in physioxia is an enhanced method of effective progenitor T and mature T-cell production ex vivo and may be of future use for HCT and T-cell immunotherapies.
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    Physioxia-induced downregulation of Tet2 in hematopoietic stem cells contributes to enhanced self-renewal
    (American Society of Hematology, 2022) Aljoufi, Arafat; Zhang, Chi; Ropa, James; Chang, Wennan; Palam, Lakshmi Reddy; Cooper, Scott; Ramdas, Baskar; Capitano, Maegan L.; Broxmeyer, Hal E.; Kapur, Reuben; Microbiology and Immunology, School of Medicine
    Hematopoietic stem cells (HSCs) manifest impaired recovery and self-renewal with a concomitant increase in differentiation when exposed to ambient air as opposed to physioxia. Mechanism(s) behind this distinction are poorly understood but have the potential to improve stem cell transplantation. Single-cell RNA sequencing of HSCs in physioxia revealed upregulation of HSC self-renewal genes and downregulation of genes involved in inflammatory pathways and HSC differentiation. HSCs under physioxia also exhibited downregulation of the epigenetic modifier Tet2. Tet2 is α-ketoglutarate, iron- and oxygen-dependent dioxygenase that converts 5-methylcytosine to 5-hydroxymethylcytosine, thereby promoting active transcription. We evaluated whether loss of Tet2 affects the number and function of HSCs and hematopoietic progenitor cells (HPCs) under physioxia and ambient air. In contrast to wild-type HSCs (WT HSCs), a complete nonresponsiveness of Tet2-/- HSCs and HPCs to changes in oxygen tension was observed. Unlike WT HSCs, Tet2-/- HSCs and HPCs exhibited similar numbers and function in either physioxia or ambient air. The lack of response to changes in oxygen tension in Tet2-/- HSCs was associated with similar changes in self-renewal and quiescence genes among WT HSC-physioxia, Tet2-/- HSC-physioxia and Tet2-/- HSC-air. We define a novel molecular program involving Tet2 in regulating HSCs under physioxia.