Hematology
Abstract
Newly produced platelets acquire a low activation state but whether the megakaryocyte plays a role in this outcome has not been fully uncovered. Mesenchymal stem cells (MSCs) were previously shown to promote platelet production and lower platelet activation. We found healthy megakaryocytes transfer mitochondria to MSCs mediated by Connexin 43 (Cx43) gap junctions on MSCs, which leads to platelets at a low energetic state with increased LYN activation, characteristic of resting platelets. On the contrary, MSCs have a limited ability to transfer mitochondria to megakaryocytes. Sickle cell disease (SCD) is characterized by hemolytic anemia and results in heightened platelet activation, contributing to numerous disease complications. Platelets in SCD mice and human patient samples had a heightened energetic state with increased glycolysis. MSC exposure to heme in SCD led to decreased Cx43 expression and a reduced ability to uptake mitochondria from megakaryocytes. This prevented LYN activation in platelets and contributed to increased platelet activation at steady state. Altogether, our findings demonstrate an effect of hemolysis in the microenvironment leading to increased platelet activation in SCD. These findings have the potential to inspire new therapeutic targets to relieve thrombosis-related complications of SCD and other hemolytic conditions.
Authors
Chengjie Gao, Yitian Dai, Paul A. Spezza, Paul Boasiako, Alice Tang, Giselle Rasquinha, Hui zhong, Bojing Shao, Yunfeng Liu, Patricia A. Shi, Cheryl A. Lobo, Xiuli An, Anqi Guo, William B. Mitchell, Deepa Manwani, Karina Yazdanbakhsh, Avital Mendelson
Abstract
Shwachman-Diamond syndrome (SDS) is characterized by neutropenia, exocrine pancreatic insufficiency, and bony abnormalities with an increased risk of myeloid neoplasia. Almost all cases of SDS result from biallelic mutations in SBDS. SBDS interacts with EFL1 to displace EIF6 from the 60S ribosomal subunit. Released EIF6 permits the assembly of ribosomal large and small subunits in the cytoplasm. Decreased EIF6 levels due to haploinsufficiency or missense mutations which lead to decreased protein expression may provide a somatic genetic rescue and anti-leukemic effects. We observed accumulation of EIF6 protein in sbds knockout (KO) zebrafish models, confirmed in patient-derived tissues, and correlated with changes in ribosome proteins and TP53 pathways. The mechanism of action for this adaptive response is unknown. To address this, we generated an eif6 zebrafish KO line which do not survive past 10 days post fertilization. We also created two mutants with low Eif6 expression, 5-25% of the wildtype levels, that can survive until adulthood. We bred them with sbds-null strains and analyzed their phenotype and biochemical properties. Low Eif6 levels reduced Tp53 pathway activation but did not rescue neutropenia in Sbds-deficient zebrafish. Further studies elucidating the interplay between SBDS, EIF6, TP53, and cellular stress responses offer promising insights into SDS pathogenesis, somatic genetic rescue, and therapeutic strategies.
Authors
Usua Oyarbide, Valentino Bezzerri, Morgan Staton, Christian Boni, Arish Shah, Marco Cipolli, Eliezer Calo, Seth J. Corey
Abstract
Although nucleoporin 98 (NUP98) fusion oncogenes often drive aggressive pediatric leukemia by altering chromatin structure and expression of HOX genes, underlying mechanisms remain elusive. Here, we report that a Hoxb-associated lncRNA HoxBlinc was aberrantly activated in NUP98-PHF23 fusion-driven leukemias. HoxBlinc chromatin occupancies led to elevated MLL1 recruitment and aberrant homeotic topologically associated domains (TADs) that enhanced chromatin accessibilities and activated homeotic/hematopoietic oncogenes. HoxBlinc-depletion in NUP98 fusion-driven leukemia impaired HoxBlinc binding, TAD integrity, MLL1 recruitment, and MLL1-driven chromatin signature within HoxBlinc-defined TADs in a CTCF-independent manner, leading to inhibited homeotic/leukemic oncogenes that mitigated NUP98 fusion-driven leukemogenesis in xenografted mouse models. Mechanistically, HoxBlinc overexpression in mouse hematopoietic compartment induced leukemias resembling those in NUP98-PHF23 knock-in mice via enhancing HoxBlinc chromatin binding, TAD formation, and Hox gene aberration leading to expansion of hematopoietic stem and progenitor cell (HSPC) and myeloid/lymphoid subpopulations. Thus, our studies reveal a CTCF-independent role of HoxBlinc in leukemic TAD organization and oncogene regulatory networks.
Authors
Karina Hamamoto, Ganqian Zhu, Qian Lai, Julia Lesperance, Huacheng Luo, Ying Li, Nupur Nigam, Arati Sharma, Feng-Chun Yang, David Claxton, Yi Qiu, Peter D. Aplan, Mingjiang Xu, Suming Huang
Abstract
Oncostatin M (OSM) is a cytokine with the unique ability to interact with both the OSM receptor (OSMR) and the leukemia inhibitory factor receptor (LIFR). On the other hand, OSMR interacts with IL31RA to form the interleukin-31 receptor. This intricate network of cytokines and receptors makes it difficult to understand the specific function of OSM. While monoallelic loss-of-function (LoF) mutations in OSMR underlie autosomal dominant familial primary localized cutaneous amyloidosis, the in vivo consequences of human OSM deficiency have never been reported so far. Here, we identified three young individuals from a consanguineous family presenting with inherited severe bone marrow failure syndromes (IBMFS) characterized by profound anemia, thrombocytopenia, and neutropenia. Genetic analysis revealed a homozygous one base-pair insertion in the sequence of OSM associated with the disease. Structural and functional analyses showed that this variant causes a frameshift that replaces the C-terminal portion of OSM, which contains the FxxK motif that interacts with both OSMR and LIFR, with a neopeptide. The lack of detection and signaling of the mutant OSM suggests a LoF mutation. Analysis of zebrafish models further supported the role of the OSM/OSMR signaling in erythroid progenitor proliferation and neutrophil differentiation. Our study provides the previously uncharacterized and unexpectedly limited in vivo consequence of OSM deficiency in humans.
Authors
Alexandrine Garrigue, Laëtitia Kermasson, Sandrine Susini, Ingrid Fert, Christopher B. Mahony, Hanem Sadek, Sonia Luce, Myriam Chouteau, Marina Cavazzana, Emmanuelle Six, Marie-Caroline Le Bousse-Kerdilès, Adrienne Anginot, Jean-Baptiste Souraud, Valérie Cormier-Daire, Marjolaine Willems, Anne Sirvent, Jennifer Russello, Isabelle Callebaut, Isabelle André, Julien Y. Bertrand, Chantal Lagresle-Peyrou, Patrick Revy
Abstract
Hematopoietic stem cells (HSCs) rely on self-renewal to sustain stem cell potential and undergo differentiation to generate mature blood cells. Mitochondrial fatty acid β-oxidation (FAO) is essential for HSC maintenance. However, the role of Carnitine palmitoyl transferase 1a (CPT1A), a key enzyme in FAO, remains unclear in HSCs. Using a Cpt1a hematopoietic specific conditional knock-out (Cpt1aΔ/Δ) mouse model, we found that loss of Cpt1a leads to HSC defects, including loss of HSC quiescence and self-renewal, and increased differentiation. Mechanistically, we find that loss of Cpt1a results in elevated levels of mitochondrial respiratory chain complex components and their activities, as well as increased ATP production, and accumulation of mitochondrial reactive oxygen species (mitoROS) in HSCs. Taken together, this suggests hyperactivation of mitochondria and metabolic rewiring via upregulated glucose-fueled oxidative phosphorylation (OXPHOS). In summary, our findings demonstrate a novel role for Cpt1a in HSC maintenance and provide insight into the regulation of mitochondrial metabolism via control of the balance between FAO and glucose-fueled OXPHOS.
Authors
Jue Li, Jie Bai, Vincent T. Pham, Michihiro Hashimoto, Maiko Sezaki, Qili Shi, Qiushi Jin, Chenhui He, Amy Armstrong, Tian Li, Mingzhe Pan, Shujun Liu, Yu Luan, Hui Zeng, Paul R. Andreassen, Gang Huang
Abstract
Ecotropic viral integration site 1 (EVI1/MECOM) is frequently upregulated in myeloid malignancies. Here, we present an Evi1-transgenic mouse model with inducible expression in hematopoietic stem/progenitor cells (HSPCs). Upon induction of Evi1 expression, mice displayed anemia, thrombocytopenia, lymphopenia, and erythroid and megakaryocyte dysplasia with a significant expansion of committed myeloid progenitor cells, resembling human myelodysplastic syndrome/myeloproliferative neoplasm–like (MDS/MPN–like) disease. Evi1 overexpression prompted HSPCs to exit quiescence and accelerated their proliferation, leading to expansion of committed myeloid progenitors while inhibiting lymphopoiesis. Analysis of global gene expression and Evi1 binding site profiling in HSPCs revealed that Evi1 directly upregulated lysine demethylase 6b (Kdm6b). Subsequently, Kdm6b-mediated H3K27me3 demethylation resulted in activation of various genes, including Laptm4b. Interestingly, KDM6B and LAPTM4B are positively correlated with EVI1 expression in patients with MDS. The EVI1/KDM6B/H3K27me3/LAPTM4B signaling pathway was also identified in EVI1hi human leukemia cell lines. We found that hyperactivation of the LAPTM4B-driven mTOR pathway was crucial for the growth of EVI1hi leukemia cells. Knockdown of Laptm4b partially rescued Evi1-induced abnormal hematopoiesis in vivo. Thus, our study establishes a mouse model to investigate EVI1hi myeloid malignancies, demonstrating the significance of the EVI1-mediated KDM6B/H3K27me3/LAPTM4B signaling axis in their maintenance.
Authors
Qiong Wu, Chunjie Yu, Fang Yu, Yiran Guo, Yue Sheng, Liping Li, Yafang Li, Yutao Zhang, Chao Hu, Jue Wang, Tong-chuan He, Yong Huang, Hongyu Ni, Zhiguang Huo, Wenshu Wu, Gang Greg Wang, Jianxin Lyu, Zhijian Qian
Abstract
Despite the revolutionary achievements of chimeric antigen receptor (CAR) T cell therapy in treating cancers, especially leukemia, several key challenges still limit its therapeutic efficacy. Of particular relevance is the relapse of cancer in large part, as a result of exhaustion and short persistence of CAR-T cells in vivo. IL-2-inducible T cell kinase (ITK) is a critical modulator of the strength of T-cell receptor (TCR) signaling, while its role in CAR signaling is unknown. By electroporation of clustered regularly interspaced short palindromic repeats (CRISPR) associated protein 9 (Cas9) ribonucleoprotein (RNP) complex into CAR-T cells, we successfully deleted ITK in CD19-CAR-T cells with high efficiency. Bulk and single-cell RNA sequencing (scRNA-seq) analyses revealed down-regulation of exhaustion and up-regulation of memory gene signatures in ITK-deficient CD19-CAR-T cells. Our results further demonstrated a significant reduction of T cell exhaustion and enhancement of T cell memory, with significant improvement of CAR-T cell expansion and persistence both in vitro and in vivo. Moreover, ITK-deficient CD19-CAR-T cells showed better control of tumor relapse. Our work provides a promising strategy of targeting ITK to develop sustainable CAR-T products for clinical use.
Authors
Zheng Fu, Zineng Huang, Hao Xu, Qingbai Liu, Jing Li, Keqing Song, Yating Deng, Yujia Tao, Huifang Zhang, Peilong Wang, Heng Li, Yue Sheng, Aijun Zhou, Lianbin Han, Yan Fu, Chen-Zhi Wang, Saurav Kumar Choudhary, Kaixiong Ye, Gianluca Veggiani, Zhihong Li, Avery August, Weishan Huang, Qiang Shan, Hongling Peng
Abstract
Proper control of inflammatory responses is essential for embryonic development, but the underlying mechanism is poorly understood. Here, we show that under physiological conditions, inactivation of ISG15, an inflammation amplifier, is associated with the interaction of Beclin 1 (Becn1), via its ECD domain, with STAT3 in the major fetal hematopoietic organ of mice. Conditional loss of Becn1 caused sequential dysfunction and exhaustion of fetal liver hematopoietic stem cells, leading to lethal inflammatory cell-biased hematopoiesis in the fetus. Molecularly, the absence of Becn1 resulted in the release of STAT3 from Becn1 tethering and subsequent phosphorylation and translocation to the nucleus, which in turn directly activated the transcription of ISG15 in fetal liver hematopoietic cells, coupled with increased ISGylation and production of inflammatory cytokines, whereas inactivating STAT3 reduced ISG15 transcription and inflammation but improved hematopoiesis potential, and further silencing ISG15 mitigated the above collapse in the Becn1 null hematopoietic lineage. The Becn1-STAT3-ISG15 axis remains functional in autophagy-disrupted fetal hematopoietic organs. These results suggest that Becn1, in an autophagy-independent manner, secures hematopoiesis and survival of the fetus by directly inhibiting STAT3-ISG15 activation to prevent cytokine storms. Our findings highlight a previously undocumented role of Becn1 in governing ISG15 to safeguard the fetus.
Authors
Wen Wei, Xueqin Gao, Jiawei Qian, Lei Li, Chen Zhao, Li Xu, Yanfei Zhu, Zhenzhen Liu, Nengrong Liu, Xueqing Wang, Zhicong Jin, Bowen Liu, Lan Xu, Jin Dong, Suping Zhang, Jiarong Wang, Yumu Zhang, Yao Yu, Zhanjun Yan, Yanjun Yang, Jie Lu, Yixuan Fang, Na Yuan, Jianrong Wang
Abstract
Severe congenital neutropenia (SCN) is frequently associated with dominant point mutations in ELANE, the gene encoding neutrophil elastase (NE). Chronic administration of granulocyte colony-stimulating factor (G-CSF) is a first-line treatment of ELANE-mutant (ELANEmut) SCN. However, some ELANEmut patients including patients with ELANE start codon mutations do not respond to G-CSF. Here, through directed granulopoiesis of gene-edited isogenic normal and patient-derived iPSCs, we demonstrate that ELANE start codon mutations suffice to induce G-CSF resistant granulocytic precursor cell death and refractory SCN. ELANE start codon mutated neutrophil precursors express predominantly nuclear N-terminal truncated alternate NE. Unlike G-CSF sensitive ELANE mutations that induce endoplasmic reticulum and unfolded protein response stress, we found that the mutation of the ELANE translation initiation codon resulted in NE aggregates and activated pro-apoptotic aggrephagy as determined by downregulated BAG1 expression, decreased BAG1/BAG3 ratio, NE co-localization with BAG3, and localized expression of autophagic LC3B. We found that SERF1, an RNA-chaperone protein, known to localize in misfolded protein aggregates in neurodegenerative diseases, was highly upregulated and interacted with cytoplasmic NE of mutant neutrophil precursors. Silencing of SERF1 enhanced survival and differentiation of iPSC-derived neutrophil precursors, restoring their responsiveness to G-CSF. These observations provide a mechanistic insight of G-CSF-resistant ELANEmut SCN, revealing targets for therapeutic intervention.
Authors
Ramesh C. Nayak, Sana Emberesh, Lisa Trump, Ashley Wellendorf, Abhishek Singh, Brice Korkmaz, Marshall S. Horwitz, Kasiani C. Myers, Theodosia A. Kalfa, Carolyn Lutzko, Jose A. Cancelas
CXCL8 secreted by immature granulocytes inhibits WT hematopoiesis in chronic myelomonocytic leukemia
Abstract
Chronic myelomonocytic leukemia (CMML) is a severe myeloid malignancy with limited therapeutic options. Single-cell analysis of clonal architecture demonstrates early clonal dominance with few residual WT hematopoietic stem cells. Circulating myeloid cells of the leukemic clone and the cytokines they produce generate a deleterious inflammatory climate. Our hypothesis is that therapeutic control of the inflammatory component in CMML could contribute to stepping down disease progression. The present study explored the contribution of immature granulocytes (iGRANs) to CMML progression. iGRANs were detected and quantified in the peripheral blood of patients by spectral and conventional flow cytometry. Their accumulation was a potent and independent poor prognostic factor. These cells belong to the leukemic clone and behaved as myeloid-derived suppressor cells. Bulk and single-cell RNA-Seq revealed a proinflammatory status of iGRAN that secreted multiple cytokines of which CXCL8 was at the highest level. This cytokine inhibited the proliferation of WT but not CMML hematopoietic stem and progenitor cells (HSPCs) in which CXCL8 receptors were downregulated. CXCL8 receptor inhibitors and CXCL8 blockade restored WT HSPC proliferation, suggesting that relieving CXCL8 selective pressure on WT HSPCs is a potential strategy to slow CMML progression and restore some healthy hematopoiesis.
Authors
Paul Deschamps, Margaux Wacheux, Axel Gosseye, Margot Morabito, Arnaud Pagès, Anne-Marie Lyne, Alexia Alfaro, Philippe Rameau, Aygun Imanci, Rabie Chelbi, Valentine Marchand, Aline Renneville, Mrinal M. Patnaik, Valerie Lapierre, Bouchra Badaoui, Orianne Wagner-Ballon, Céline Berthon, Thorsten Braun, Christophe Willekens, Raphael Itzykson, Pierre Fenaux, Sylvain Thépot, Gabriel Etienne, Emilie Elvira-Matelot, Francoise Porteu, Nathalie Droin, Leïla Perié, Lucie Laplane, Eric Solary, Dorothée Selimoglu-Buet
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)