Multiple myeloma (MM) is characterized by an accumulation of malignant plasma cells (PCs) within the bone marrow (BM). The BM microenvironment supports survival of the malignant cells and is comprised of cellular fractions that foster myeloma development and progression by suppression of the immune response. Despite major progress in understanding the biology and pathophysiology of MM, this disease is still incurable and requires aggressive treatment with significant side effects. CD84 is a self-binding immuno-receptor belonging to the signaling lymphocyte activating molecule (SLAM) family. Previously, we showed that CD84 bridges between chronic lymphocytic leukemia cells and their microenvironment, and regulates T cell function. In the current study, we investigated the role of CD84 in MM. Our results show that MM cells express low levels of CD84. However, these cells secrete the cytokine macrophage migration inhibitory factor (MIF), which induces CD84 expression on cells in their microenvironment. Its activation leads to an elevation of expression of genes regulating differentiation to M/G- myeloid derived suppressor cells (MDSCs) and upregulation of PD-L1 expression on MDSCs, which together suppress T cell function. Downregulation of CD84 or its blocking reduces MDSC accumulation, resulting in elevated T cell activity and reduced tumor load. Our data suggest that CD84 might serve as a novel therapeutic target in MM.
Hadas Lewinsky, Emine Gulsen Gunes, Keren David, Lihi Radomir, Matthias P. Kramer, Bianca Pellegrino, Michal Perpinial, Jing Chen, Ting-fang He, Anthony Mansour, Kun-Yu Teng, Supriyo Bhattacharya, Enrico Caserta, Estelle Troadec, Peter P. Lee, Mingye Feng, Jonathan J. Keats, Amrita Krishnan, Michael Rosenzweig, Jianhua Yu, Michael A. Caligiuri, Yosef Cohen, Olga Shvetz, Shirly Becker-Herman, Flavia Pichiorri, Steven Rosen, Idit Shachar
The cohesin complex plays an essential role in chromosome maintenance and transcriptional regulation. Recurrent somatic mutations in the cohesin complex are frequent genetic drivers in cancer including myelodysplatic syndromes (MDS) and acute myeloid leukemia (AML). Here, using genetic dependency screens of STAG2-mutant AML, we identified DNA damage repair and replication as genetic dependencies in cohesin-mutant cells. We demonstrated increased levels of DNA damage and sensitivity of cohesin-mutant cells to PARP inhibition. We developed a mouse model of MDS in which Stag2 mutations arise as clonal secondary lesions in the background of clonal hematopoiesis driven by Tet2 mutations, and demonstrated selective depletion of cohesin-mutant cells with PARP inhibition in vivo. Finally, we demonstrated a shift from STAG2- to STAG1-containing cohesin complexes in cohesin-mutant cells, which is associated with longer DNA loop extrusion, more intermixing of chromatin compartments, and increased interaction with PARP and RPA proteins. Our findings inform the biology and therapeutic opportunities for cohesin-mutant malignancies.
Zuzana Tothova, Anne-Laure Valton, Rebecca Gorelov, Mounica Vallurupalli, John M. Krill-Burger, Amie Holmes, Catherine C. Landers, J. Erika Haydu, Edyta Malolepsza, Christina R. Hartigan, Melanie Donahue, Katerina D. Popova, Sebastian H. J. Koochaki, Sergey V. Venev, Jeanne F. Rivera, Edwin Chen, Kasper Lage, Monica Schenone, Alan D. D'Andrea, Steven A. Carr, Elizabeth A. Morgan, Job Dekker, Benjamin L. Ebert
Computational models based on recent maps of the red blood cell proteome suggest that mature erythrocytes may harbor targets for common drugs. This prediction is relevant to red blood cell storage in the blood bank, in which the impact of small molecule drugs or other xenometabolites deriving from dietary, iatrogenic or environmental exposures (“exposome”) may alter erythrocyte energy and redox metabolism and, in so doing, affect red cell storage quality and post-transfusion efficacy. To test this prediction, here we provide a comprehensive characterization of the blood donor exposome, including the detection of common prescription and over-the-counter drugs in 250 units donated by healthy volunteers from the REDS-III RBC Omics study. Based on high-throughput drug screenings of 1,366 FDA-approved drugs, we report a significant impact of ~65% of the tested drugs on erythrocyte metabolism. Machine learning models built using metabolites as predictors were able to accurately predict drugs for several drug classes/targets (bisphosphonates, anticholinergics, calcium channel blockers, adrenergics, proton-pump inhibitors, antimetabolites, selective serotonin reuptake inhibitors, and mTOR) suggesting that these drugs have a direct, conserved, and significant impact on erythrocyte metabolism. As a proof of principle, here we show that the antiacid ranitidine – though rarely detected in the blood donor population – has a strong effect on RBC markers of storage quality in vitro. We thus show that ranitidine supplementation to blood units could improve erythrocyte metabolism and storage quality when supplemented to blood bags, through mechanisms involving sphingosine 1-phosphate-dependent modulation of erythrocyte glycolysis and/or direct binding to hemoglobin.
Travis Nemkov, Davide Stefanoni, Aarash Bordbar, Aaron Issaian, Bernhard O. Palsson, Larry J. Dumont, Ariel M. Hay, Anren Song, Yang Xia, Jasmina S. Redzic, Elan Z. Eisenmesser, James C. Zimring, Steve Kleinman, Kirk C. Hansen, Michael Busch, Angelo D’Alessandro
Effective treatment for AML is challenging due to the presence of clonal heterogeneity and the evolution of polyclonal drug resistance. Here, we report that TP-0903 has potent activity against protein kinases related to STAT, AKT, and ERK signaling, as well as cell cycle regulators in biochemical and cellular assays. In vitro and in vivo, TP-0903 was active in multiple models of drug-resistant FLT3 mutant AML, including those involving the F691L gatekeeper mutation and bone marrow microenvironment–mediated factors. Furthermore, TP-0903 demonstrated preclinical activity in AML models with FLT3-ITD and common co-occurring mutations in IDH2 and NRAS genes. We also showed that TP-0903 had ex vivo activity in primary AML cells with recurrent mutations including MLL-PTD, ASXL1, SRSF2, and WT1, which are associated with poor prognosis or promote clinical resistance to AML-directed therapies. Our preclinical studies demonstrate that TP-0903 is a multikinase inhibitor with potent activity against multiple drug-resistant models of AML that will have an immediate clinical impact in a heterogeneous disease like AML.
Jae Yoon Jeon, Daelynn R. Buelow, Dominique A. Garrison, Mingshan Niu, Eric D. Eisenmann, Kevin M. Huang, Megan E. Zavorka Thomas, Robert H. Weber, Clifford J. Whatcott, Steve L. Warner, Shelley J. Orwick, Bridget Carmichael, Emily Stahl, Lindsey T. Brinton, Rosa Lapalombella, James S. Blachly, Erin Hertlein, John C. Byrd, Bhavana Bhatnagar, Sharyn D. Baker
The nonimmune roles of Tregs have been described in various tissues, including the BM. In this study, we comprehensively phenotyped marrow Tregs, elucidating their key features and tissue-specific functions. We show that marrow Tregs are migratory and home back to the marrow. For trafficking, marrow Tregs use S1P gradients, and disruption of this axis allows for specific targeting of the marrow Treg pool. Following Treg depletion, the function and phenotype of both mesenchymal stromal cells (MSCs) and hematopoietic stem cells (HSCs) was impaired. Transplantation also revealed that a Treg-depleted niche has a reduced capacity to support hematopoiesis. Finally, we found that marrow Tregs are high producers of IL-10 and that Treg-secreted IL-10 has direct effects on MSC function. This is the first report to our knowledge revealing that Treg-secreted IL-10 is necessary for stromal cell maintenance, and our work outlines an alternative mechanism by which this cytokine regulates hematopoiesis.
Virginia Camacho, Victoria R. Matkins, Sweta B. Patel, Jeremie M. Lever, Zhengqin Yang, Li Ying, Ashley E. Landuyt, Emma C. Dean, James F. George, Henry Yang, Paul Brent Ferrell, Craig L. Maynard, Casey T. Weaver, Heth R. Turnquist, Robert S. Welner
ETV6 is an ETS family transcription factor which plays a key role in hematopoiesis and megakaryocyte development. Our group and others have identified germline mutations in ETV6 resulting in autosomal dominant thrombocytopenia and predisposition to malignancy; however, molecular mechanisms defining the role of ETV6 in megakaryocyte development have not been well established. Using a combination of molecular, biochemical, and sequencing approaches in patient-derived PBMCs, we demonstrate abnormal cytoplasmic localization of ETV6 and the HDAC3/NCOR2 repressor complex that leads to overexpression of HDAC3-regulated interferon response genes. This transcriptional dysregulation is also reflected in patient-derived platelet transcripts, and drives aberrant proplatelet formation in megakaryocytes. Our results suggest that aberrant transcription may predispose patients with ETV6 mutations to bone marrow inflammation, dysplasia, and megakaryocyte dysfunction.
Marlie H. Fisher, Gregory D. Kirkpatrick, Brett M. Stevens, Courtney L. Jones, Michael U. Callaghan, Madhvi Rajpurkar, Joy Fulbright, Megan A. Cooper, Jesse Rowley, Christopher C. Porter, Arthur Gutierrez-Hartmann, Kenneth Jones, Craig T. Jordan, Eric M. Pietras, Jorge Di Paola
Recently, we demonstrated that hematopoietic stem/progenitor cell (HSPC) mobilization followed by intravenous injection of integrating, helper-dependent adenovirus HDAd5/35++ vectors resulted in efficient transduction of long-term repopulating cells and disease amelioration in mouse models after in vivo selection of transduced HSPCs. Acute innate toxicity associated with HDAd5/35++ injection was controlled by appropriate prophylaxis, making this approach feasible for clinical translation. Our ultimate goal is to use this technically simple in vivo HSPC transduction approach for gene therapy of thalassemia major or sickle cell disease. A cure of these diseases requires high expression levels of the therapeutic protein (γ- or β-globin), which is difficult to achieve with lentivirus vectors because of their genome size limitation not allowing larger regulatory elements to be accommodated. Here, we capitalized on the 35 kb insert capacity of HDAd5/35++ vectors to demonstrate that transcriptional regulatory regions of the β-globin locus with a total length of 29 kb can efficiently be transferred into HSPCs. The in vivo HSPC transduction resulted in stable γ-globin levels in erythroid cells that conferred a complete cure of murine thalassemia intermedia. Notably, this was achieved with a minimal in vivo HSPC selection regimen.
Hongjie Wang, Aphrodite Georgakopoulou, Chang Li, Zhinan Liu, Sucheol Gil, Ashvin Bashyam, Evangelia Yannaki, Achilles Anagnostopoulos, Amit Pande, Zsuzsanna Izsvák, Thalia Papayannopoulou, André Lieber
Shwachman-Diamond syndrome (SDS) is characterized by exocrine pancreatic insufficiency, neutropenia, and skeletal abnormalities. Biallelic mutations in SBDS, which encodes a ribosome maturation factor, are found in 90% of SDS cases. Sbds-/- mice are embryonic lethal. Using CRISPR/Cas9 editing, we created sbds-deficient zebrafish strains. Sbds protein levels progressively decreased and became undetectable at 10 days post fertilization (dpf). Polysome analysis revealed decreased 80S ribosomes. Homozygous mutant fish developed normally until 15 dpf. Mutant fish subsequently have stunted growth and shows signs of atrophy in pancreas, liver, and intestine. In addition, neutropenia occurred by 5 dpf. Upregulation of tp53 mRNA did not occur until 10 dpf and inhibition of proliferation correlating with death by 21 dpf. Transcriptome analysis showed tp53 activation through upregulation of genes involved in cell cycle arrest, cdkn1a and ccng1, and apoptosis, puma and mdm2. However, elimination of Tp53 function did not prevent lethality. Because of growth retardation and atrophy of intestinal epithelia, we studied the effects of starvation on wildtype fish. Starved wildtype fish showed intestinal atrophy, zymogen granule loss, and tp53 upregulation – similar to the mutant phenotype. In addition, there was reduction in neutral lipid storage and ribosomal protein amount, similar to the mutant phenotype. Thus, loss of Sbds in zebrafish phenocopies much of the human disease and is associated with growth arrest and tissue atrophy, particularly of the gastrointestinal system, at the larval stage. A variety of stress responses, some associated with Tp53, contribute to pathophysiology of SDS.
Usua Oyarbide, Arish N. Shah, Wilmer Amaya-Mejia, Matthew Snyderman, Margaret Kell, Daniela Allende, Eliezer Calo, Jacek Topczewski, Seth Corey
Myelodysplastic syndromes (MDS) are clonal malignant hematopoietic disorders in the elderly characterized by ineffective hematopoiesis. This is accompanied by an altered bone microenvironment, which contributes to MDS progression and higher bone fragility. The underlying mechanisms remain largely unexplored. Here, we show that myelodysplastic NUP98‑HOXD13 (NHD13) transgenic mice display an abnormally high number of osteoblasts, yet a higher fraction of nonmineralized bone, indicating delayed bone mineralization. This was accompanied by high fibroblast growth factor-23 (FGF-23) serum levels, a phosphaturic hormone that inhibits bone mineralization and erythropoiesis. While Fgf23 mRNA expression was low in bone, brain, and kidney of NHD13 mice, its expression was increased in erythroid precursors. Coculturing these precursors with WT osteoblasts induced osteoblast marker gene expression, which was inhibited by blocking FGF-23. Finally, antibody-based neutralization of FGF-23 in myelodysplastic NHD13 mice improved bone mineralization and bone microarchitecture, and it ameliorated anemia. Importantly, higher serum levels of FGF‑23 and an elevated amount of nonmineralized bone in patients with MDS validated the findings. C‑terminal FGF‑23 correlated negatively with hemoglobin levels and positively with the amount of nonmineralized bone. Thus, our study identifies FGF-23 as a link between altered bone structure and ineffective erythropoiesis in MDS with the prospects of a targeted therapeutic intervention.
Heike Weidner, Ulrike Baschant, Franziska Lademann, Maria G. Ledesma Colunga, Ekaterina Balaian, Christine Hofbauer, Barbara M. Misof, Paul Roschger, Stéphane Blouin, William G. Richards, Uwe Platzbecker, Lorenz C. Hofbauer, Martina Rauner
Ribosomopathies are congenital disorders caused by mutations in the genes encoding ribosomal and other functionally related proteins. They are characterized by anemia, other hematopoietic and developmental abnormalities, and p53 activation. Ribosome assembly requires coordinated expression of many ribosomal protein (RP) genes; however, the regulation of RP gene expression, especially in hematopoietic stem cells (HSCs), remains poorly understood. MYSM1 is a transcriptional regulator essential for HSC function and hematopoiesis. We established that HSC dysfunction in Mysm1 deficiency is driven by p53; however, the mechanisms of p53 activation remained unclear. Here, we describe the transcriptome of Mysm1-deficient mouse HSCs and identify MYSM1 genome-wide DNA binding sites. We establish a direct role for MYSM1 in RP gene expression and show a reduction in protein synthesis in Mysm1–/– HSCs. Loss of p53 in mice fully rescues Mysm1–/– anemia phenotype but not RP gene expression, indicating that RP gene dysregulation is a direct outcome of Mysm1 deficiency and an upstream mediator of Mysm1–/– phenotypes through p53 activation. We characterize a patient with a homozygous nonsense MYSM1 gene variant, and we demonstrate reduced protein synthesis and increased p53 levels in patient hematopoietic cells. Our work provides insights into the specialized mechanisms regulating RP gene expression in HSCs and establishes a common etiology of MYSM1 deficiency and ribosomopathy syndromes.
Jad I. Belle, HanChen Wang, Amanda Fiore, Jessica C. Petrov, Yun Hsiao Lin, Chu-Han Feng, Thi Tuyet Mai Nguyen, Jacky Tung, Philippe M. Campeau, Uta Behrends, Theresa Brunet, Gloria Sarah Leszinski, Philippe Gros, David Langlais, Anastasia Nijnik
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