Hematology
Abstract
Authors
Hajime Senjo, Daigo Hashimoto, Takanori Teshima
Abstract
Lung megakaryocytes (Mks) are largely extravascular with an immune phenotype (1). Because bone marrow (BM) Mks are short-lived it has been assumed that extravascular lung Mks are constantly ‘seeded’ from the BM. To investigate lung Mk origins and how that impacts their functions, we developed methods to specifically label lung Mks using CFSE dye and biotin delivered oropharyngeal. Labeled lung Mks were present for up to four months, while BM Mks had a <1 week lifespan. In a parabiosis model, lung Mks were partially replaced over 1-month from a circulating source. Unlike tissue-resident macrophages, using MDS1-Cre-ERT2 TdTomato mice, we found that lung Mks arise from hematopoietic stem cells. However, studies with FlkSwitch mTmG mice showed that lung Mks are derived from a Flt3-independent lineage that does not go through a multipotent progenitor. CFSE labeling to track lung Mk-derived platelets showed that about 10% of circulating platelets are lung resident Mk-derived at steady state, but in sterile thrombocytopenia this was doubled (about 20%). Lung-derived platelets were similarly increased in a malaria infection model (Plasmodium yoelii) typified by thrombocytopenia. These studies indicate that lung Mks arise from a Flt3-negative BM source, are long-lived, and contribute more platelets during thrombocytopenia.
Authors
Alison C. Livada, Kathleen E. McGrath, Michael W. Malloy, Chen Li, Sara K. Ture, Paul D. Kingsley, Anne D. Koniski, Leah A. Vit, Katherine E. Nolan, Deanne Mickelsen, Grace E. Monette, Preeti Maurya, James Palis, Craig N. Morrell
Abstract
The ubiquitously expressed small GTPase Ras-related protein 1B (RAP1B) acts as a molecular switch that regulates cell signaling, cytoskeletal remodeling, and cell trafficking and activates integrins in platelets and lymphocytes. The residue G12 in the P-loop is required for the RAP1B-GTPase conformational switch. Heterozygous germline RAP1B variants have been described in patients with syndromic thrombocytopenia. However, the causality and pathophysiological impact remained unexplored. We report a boy with neonatal thrombocytopenia, combined immunodeficiency, neutropenia, and monocytopenia caused by a heterozygous de novo single nucleotide substitution, c.35G>A (p.G12E) in RAP1B. We demonstrate that G12E and the previously described G12V and G60R were gain-of-function variants that increased RAP1B activation, talin recruitment, and integrin activation, thereby modifying late responses such as platelet activation, T cell proliferation, and migration. We show that in our patient, G12E was a somatic variant whose allele frequency decreased over time in the peripheral immune compartment, but remained stable in bone marrow cells, suggesting a differential effect in distinct cell populations. Allogeneic hematopoietic stem cell transplantation fully restored the patient’s hemato-immunological phenotype. Our findings define monoallelic RAP1B gain-of-function variants as a cause for constitutive immunodeficiency and thrombocytopenia. The phenotypic spectrum ranged from isolated hematological manifestations in our patient with somatic mosaicism to complex syndromic features in patients with reported germline RAP1B variants.
Authors
Marta Benavides-Nieto, Frédéric Adam, Emmanuel Martin, Charlotte Boussard, Chantal Lagresle-Peyrou, Isabelle Callebaut, Alexandre Kauskot, Christelle Repérant, Miao Feng, Jean-Claude Bordet, Martin Castelle, Guillaume Morelle, Chantal Brouzes, Mohammed Zarhrate, Patricia Panikulam, Nathalie Lambert, Capucine Picard, Damien Bodet, Jérémie Rouger-Gaudichon, Patrick Revy, Jean-Pierre de Villartay, Despina Moshous
Abstract
Background. Donor cell engraftment is a pre-requisite of successful allogeneic hematopoietic stem cell transplantation. Based on peripheral blood analyses it is characterized by early myeloid recovery and T- and B-cells lymphopenia. However, cellular networks associated with bone marrow engraftment of allogeneic human cells have been poorly described. Methods. Mass cytometry and CITEseq analyses were performed on bone marrow cells, three months post-transplant in patients with acute myelogenous leukemia. Results. Mass cytometry in 26 patients and 20 healthy controls disclosed profound alterations in myeloid and B-cell progenitors, with a shift towards terminal myeloid differentiation and decreased B-cell progenitors. Unsupervised analysis separated recipients into 2 groups, one of them being driven by previous GVHD (R2 patients). We then used single-cell CITEseq to decipher engraftment, which resolved 36 clusters, encompassing all bone marrow cellular components. Hematopoiesis in transplant recipients was sustained by committed myeloid and erythroid progenitors in a setting of monocytes-, NK cells- and T-cells mediated inflammation. Gene expression disclosed major pathways in transplant recipients, namely, TNFα signaling via NFκ-B, and interferon-γ response. The hallmark of allograft rejection was consistently found in clusters from transplant recipients, especially in R2 recipients. Conclusion. Bone marrow cell engraftment of allogeneic donor cells is characterized by a state of emergency hematopoiesis in the setting of allogeneic response driving inflammation. Trial registration. Not applicable. Funding. This study has been supported by the French National Cancer Institute (Institut National du Cancer): PLBIO19-239 and by an unrestricted research grant by Alexion Pharmaceutical.
Authors
Jennifer Bordenave, Dorota Gajda, David Michonneau, Nicolas Vallet, Mathieu F. Chevalier, Emmanuelle Clappier, Pierre Lemaire, Stéphanie Mathis, Marie Robin, Aliénor Xhaard, Flore Sicre de Fontbrune, Aurélien Corneau, Sophie Caillat-Zucman, Regis PEFFAULT de LATOUR, Emmanuel Curis, Gerard Socie
Abstract
Activating mutations of FLT3 contribute to deregulated hematopoietic stem and progenitor cell (HSC/Ps) growth and survival in patients with acute myeloid leukemia (AML), leading to poor overall survival. AML patients treated with investigational drugs targeting mutant FLT3, including Quizartinib and Crenolanib, develop resistance to these drugs. Development of resistance is largely due to acquisition of cooccurring mutations and activation of additional survival pathways, as well as emergence of additional FLT3 mutations. Despite the high prevalence of FLT3 mutations and their clinical significance in AML, there are few targeted therapeutic options available. We have identified 2 novel nicotinamide-based FLT3 inhibitors (HSN608 and HSN748) that target FLT3 mutations at subnanomolar concentrations and are potently effective against drug-resistant secondary mutations of FLT3. These compounds show antileukemic activity against FLT3ITD in drug-resistant AML, relapsed/refractory AML, and in AML bearing a combination of epigenetic mutations of TET2 along with FLT3ITD. We demonstrate that HSN748 outperformed the FDA-approved FLT3 inhibitor Gilteritinib in terms of inhibitory activity against FLT3ITD in vivo.
Authors
Baskar Ramdas, Neetu Dayal, Ruchi Pandey, Elizabeth Larocque, Rahul Kanumuri, Santhosh Kumar Pasupuleti, Sheng Liu, Chrysi Kanellopoulou, Elizabeth Fei Yin Chu, Rodrigo Mohallem, Saniya Virani, Gaurav Chopra, Uma K. Aryal, Rena Lapidus, Jun Wan, Ashkan Emadi, Laura S. Haneline, Frederick W. Holtsberg, M. Javad Aman, Herman O. Sintim, Reuben Kapur
Abstract
BACKGROUND. Predicting Immune-effector Cell Associated Neurotoxicity Syndrome (ICANS) in patients infused with Chimeric Antigen Receptor T cells (CAR-T) is still a conundrum. This complication, thought to be consequent to CAR-T cell activation, arises a few days after infusion, when circulating CAR-T cells are scarce and specific CAR-T cell-derived biomarkers are lacking. METHODS. Human CD19.CAR-T cells were generated to gain insight into CAR+ extracellular vesicle (CAR+EV) release upon target engagement. A prospective cohort of 100 B-cell lymphoma patients infused with approved CD19.CAR-T cell products (axi-cel, brexu-cel and tisa-cel) was assessed for plasma CAR+EVs as potential biomarkers of in vivo CD19.CAR-T cell activation and predictors of ICANS. Human induced pluripotent stem cells (iPSCs)-derived neural cells were used as a model for CAR+EV-induced neurotoxicity. RESULTS. In vitro, exosome-like CAR+EVs were released by CD19.CAR-T cells upon target engagement. In vivo, CAR+EVs were detectable as early as 1 hour in the plasma of patients. A concentration > 132.8 CAR+EVs/μl at hour +1 or > 224.5 CAR+EVs/μl at day +1 predicted ICANS in advance of 4 days, with a sensitivity up to 96.55% and a specificity up to 80.36%, outperforming other potential ICANS predictors. Enolase 2 (ENO2+) nanoparticles were released by iPSCs-derived neural cells upon CAR+EVs exposure and were increased in the plasma of ICANS patients. CONCLUSIONS. These results convey that plasma CAR+EVs are an immediate signal of CD19.CAR-T cell activation, are suitable predictors of neurotoxicity, and may be involved in ICANS pathogenesis. TRIAL REGISTRATION. NCT04892433, NCT05807789.
Authors
Gianluca Storci, Francesco De Felice, Francesca Ricci, Spartaco Santi, Daria Messelodi, Salvatore Nicola Bertuccio, Noemi Laprovitera, Michele Dicataldo, Lucrezia Rossini, Serena De Matteis, Beatrice Casadei, Francesca Vaglio, Margherita Ursi, Francesco Barbato, Marcello Roberto, Maria Guarino, Gian Maria Asioli, Mario Arpinati, Pietro Cortelli, Enrico Maffini, Enrica Tomassini, Marta Tassoni, Carola Cavallo, Francesco Iannotta, Maria Naddeo, Pier Luigi Tazzari, Elisa Dan, Cinzia Pellegrini, Serafina Guadagnuolo, Matteo Carella, Barbara Sinigaglia, Chiara Pirazzini, Caterina Severi, Paolo Garagnani, Katarzyna Malgorzata Kwiatkowska, Manuela Ferracin, Pier Luigi Zinzani, Massimiliano Bonafè, Francesca Bonifazi
Abstract
Splicing factor mutations are common in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), but how they alter cellular functions is unclear. We show that the pathogenic SRSF2P95H/+ mutation disrupts the splicing of mitochondrial mRNAs, impairs mitochondrial complex I function, and robustly increases mitophagy. We also identified a mitochondrial surveillance mechanism by which mitochondrial dysfunction modifies splicing of the mitophagy activator PINK1 to remove a poison intron, increasing the stability and abundance of PINK1 mRNA and protein. SRSF2P95H-induced mitochondrial dysfunction increased PINK1 expression through this mechanism, which is essential for survival of SRSF2P95H/+ cells. Inhibition of splicing with a glycogen synthase kinase 3 inhibitor promoted retention of the poison intron, impairing mitophagy and activating apoptosis in SRSF2P95H/+ cells. These data reveal a homeostatic mechanism for sensing mitochondrial stress through PINK1 splicing and identify increased mitophagy as a disease marker and a therapeutic vulnerability in SRSF2P95H mutant MDS and AML.
Authors
Xiaolei Liu, Sudhish A. Devadiga, Robert F. Stanley, Ryan M. Morrow, Kevin A. Janssen, Mathieu Quesnel-Vallières, Oz Pomp, Adam A. Moverley, Chenchen Li, Nicolas Skuli, Martin P. Carroll, Jian Huang, Douglas C. Wallace, Kristen W. Lynch, Omar Abdel-Wahab, Peter S. Klein
Abstract
T cell acute lymphoblastic leukemia (T-ALL) is an aggressive immature T cell cancer. Mutations in IL7R have been analyzed genetically, but downstream effector functions such as STAT5A and STAT5B hyperactivation are poorly understood. Here, we studied the most frequent and clinically challenging STAT5BN642H driver in T cell development and immature T cell cancer onset and compared it with STAT5A hyperactive variants in transgenic mice. Enhanced STAT5 activity caused disrupted T cell development and promoted an early T cell progenitor–ALL phenotype, with upregulation of genes involved in T cell receptor (TCR) signaling, even in absence of surface TCR. Importantly, TCR pathway genes were overexpressed in human T-ALL and mature T cell cancers and activation of TCR pathway kinases was STAT5 dependent. We confirmed STAT5 binding to these genes using ChIP-Seq analysis in human T-ALL cells, which were sensitive to pharmacologic inhibition by dual STAT3/5 degraders or ZAP70 tyrosine kinase blockers in vitro and in vivo. We provide genetic and biochemical proof that STAT5A and STAT5B hyperactivation can initiate T-ALL through TCR pathway hijacking and suggest similar mechanisms for other T cell cancers. Thus, STAT5 or TCR component blockade are targeted therapy options, particularly in patients with chemoresistant clones carrying STAT5BN642H.
Authors
Tobias Suske, Helena Sorger, Gabriele Manhart, Frank Ruge, Nicole Prutsch, Mark W. Zimmerman, Thomas Eder, Diaaeldin I. Abdallah, Barbara Maurer, Christina Wagner, Susann Schönefeldt, Katrin Spirk, Alexander Pichler, Tea Pemovska, Carmen Schweicker, Daniel Pölöske, Emina Hubanic, Dennis Jungherz, Tony Andreas Müller, Myint Myat Khine Aung, Anna Orlova, Ha Thi Thanh Pham, Kerstin Zimmel, Thomas Krausgruber, Christoph Bock, Mathias Müller, Maik Dahlhoff, Auke Boersma, Thomas Rülicke, Roman Fleck, Elvin Dominic de Araujo, Patrick Thomas Gunning, Tero Aittokallio, Satu Mustjoki, Takaomi Sanda, Sylvia Hartmann, Florian Grebien, Gregor Hoermann, Torsten Haferlach, Philipp Bernhard Staber, Heidi Anne Neubauer, Alfred Thomas Look, Marco Herling, Richard Moriggl
Abstract
Chimeric antigen receptor (CAR) designs that incorporate pharmacologic control are desirable, however designs suitable for clinical translation are needed. We designed a fully human, rapamycin-regulated, drug product for targeting CD33+ tumors called dimerization agent regulated immunoreceptor complex (DARIC33). T cell products demonstrated target specific and rapamycin-dependent cytokine release, transcriptional responses, cytotoxicity, and in vivo antileukemic activity in the presence of as little as 1nM rapamycin. Rapamycin withdrawal paused DARIC33-stimulated T cell effector functions, which were restored following re-exposure to rapamycin, demonstrating reversible effector function control. While rapamycin-regulated DARIC33 T cells were highly sensitive to target antigen, CD34+ stem cell colony forming capacity was not impacted. We benchmarked DARIC33 potency relative to CD19 CAR T cells to estimate a T cell dose for clinical testing. In addition, we integrated in vitro and preclinical in vivo drug concentration thresholds for OFF-ON state transitions, as well as murine and human rapamycin pharmacokinetics, to estimate a clinically applicable rapamycin dosing schedule. A phase 1 DARIC33 trial has been initiated (PLAT-08, NCT05105152), with initial evidence of rapamycin-regulated T cell activation and anti-tumor impact. Our findings provide evidence that the DARIC platform exhibits sensitive regulation and potency needed for clinical application to other important immunotherapy targets.
Authors
Jacob Appelbaum, April E. Price, Kaori Oda, Joy Zhang, Wai-Hang Leung, Giacomo Tampella, Dong Xia, Pauline P.L. So, Sarah K. Hilton, Claudya Evandy, Semanti Sarkar, Unja Martin, Anne-Rachel Krostag, Marissa Leonardi, Daniel E. Zak, Rachael Logan, Paula Lewis, Secil Franke-Welch, Njabulo Ngwenyama, Michael Fitzgerald, Niklas Tulberg, Stephanie Rawlings-Rhea, Rebecca A. Gardner, Kyle Jones, Angelica Sanabria, William Crago, John Timmer, Andrew Hollands, Brendan Eckelman, Sanela Bilic, Jim Woodworth, Adam Lamble, Philip D. Gregory, Jordan Jarjour, Mark Pogson, Joshua A. Gustafson, Alexander Astrakhan, Michael C. Jensen
Abstract
Chromosomal instability is a prominent biological feature of Myelodysplastic Syndromes (MDS), with over 50% of MDS patients harboring chromosomal abnormalities or a complex karyotype. Despite this observation, the mechanisms underlying mitotic and chromosomal defects in MDS remain elusive. In this study, we identified a ectopic expression of transcription factor ONECUT3, associated with complex karyotypes and poorer survival outcomes in MDS. ONECUT3-overexpressing cell models exhibited enrichment of several notable pathways, including signatures of sister chromosome exchange separation and mitotic nuclear division with the upregulation of INCENP and CDCA8 genes. Notably, dysregulation of Chromosome Passenger Complex (CPC) accumulation besides the cell equator and midbody during mitotic phases consequently caused cytokinesis failure and defective chromosome segregation. Mechanistically, the Homeobox (HOX) domain of ONECUT3, serving as the DNA binding domain, occupied the unique genomic regions of INCENP and CDCA8, and transcriptionally activated these two genes. A novel lead compound C5484617, was identified that functionally targeted the HOX domain of ONECUT3 inhibiting its transcriptional activity on downstream genes, and synergistically resensitized MDS cells to hypomethylating agents. This study revealed that ONECUT3 promoted chromosomal instability by transcriptional activation of INCENP and CDCA8, suggesting potential prognosis and therapeutic roles for targeting high-risk MDS patients with complex karyotype.
Authors
Yingwan Luo, Xiaomin Feng, Wei Lang, Weihong Xu, Wei Wang, Chen Mei, Li Ye, Shuanghong Zhu, Lu Wang, Xinping Zhou, Huimin Zeng, Liya Ma, Yanling Ren, Jie Jin, Rongzhen Xu, Gang Huang, Hongyan Tong
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)