Hematology
Abstract
CAR-T therapy has led to significant improvements in patient survival. However, a subset of patients experience high-grade toxicities, including cytokine release syndrome (CRS) and immune cell-associated hematological toxicity (ICAHT). We utilized IL-2Rα knockout mice to model toxicities with elevated levels of IL6, IFNγ, and TNFα and increased M1-like macrophages. Onset of CRS was accompanied by a reduction in peripheral blood neutrophils due to disruption of bone marrow neutrophil homeostasis characterized by an increase in apoptotic neutrophils and a decrease in proliferative and mature neutrophils. Both non-tumor-bearing and Eμ-ALL tumor-bearing mice recapitulated the co-occurrence of CRS and neutropenia. IFNγ-blockade alleviated CRS and neutropenia without affecting CAR-T efficacy. Mechanistically, a Th1-Th17 imbalance was observed to drive co-occurrence of CRS and neutropenia in an IFNγ-dependent manner leading to decreased IL-17A and G-CSF, neutrophil production, and neutrophil survival. In patients, we observed an increase in the IFNγ-to-IL-17A ratio in the peripheral blood during high-grade CRS and neutropenia. We have uncovered a biological basis for ICAHT and provide support for the use of IFNγ-blockade to reduce both CRS and neutropenia.
Authors
Payal Goala, Yongliang Zhang, Nolan J. Beatty, Allan Pavy, Shannon L. McSain, Cooper J. Sailer, Muhammad Junaid Tariq, Showkat Hamid, Eduardo Cortes Gomez, Jianmin Wang, Duna Massillon, Maxwell Ilecki, Justin C. Boucher, Constanza Savid-Frontera, Sae Bom Lee, Hiroshi Kotani, Meredith L. Stone, Michael D. Jain, Marco L. Davila
Abstract
The adaptor protein LNK/SH2B3 negatively regulates hematopoietic stem cell (HSC) homeostasis. Lnk-deficient mice show marked expansion of HSCs without premature exhaustion. Lnk deficiency largely restores HSC function in Fanconi Anemia (FA) mouse models and primary FA patient cells, albeit protective mechanisms remain enigmatic. Here, we uncover a novel role for LNK in regulating translesion synthesis (TLS) during HSC replication. Lnk deficiency reduced replication stress-associated DNA damage, particularly in the FA background. Lnk deficiency suppressed single-strand DNA breaks, while enhancing replication fork restart in FA-deficient HSCs. Diminished replication-associated damage in Lnk-deficient HSCs occurred commensurate with reduced ATR-p53 checkpoint activation that is linked to HSC attrition. Notably, Lnk deficiency ameliorated HSC attrition in FA mice without exacerbating carcinogenesis during ageing. Moreover, we demonstrated that enhanced HSC fitness from Lnk deficiency was associated with increased TLS activity via REV1 and, to a lesser extent, TLS polymerase eta. TLS polymerases are specialized to execute DNA replication in the presence of lesions or natural replication fork barriers that stall replicative polymerases. Our findings implicate elevated use of these specialized DNA polymerases as critical to the enhanced HSC function imparted by Lnk deficiency, which has important ramifications for stem cell therapy and regenerative medicine in general.
Authors
Brijendra Singh, Md Akram Hossain, Xiao Hua Liang, Jeremie Fages, Carlo Salas Salinas, Roger A. Greenberg, Wei Tong
Abstract
There is an urgent need to find targeted agents for T-cell acute lymphoblastic leukemia (T-ALL). NOTCH1 is the most frequently mutated oncogene in T-ALL, but clinical trials showed that pan-Notch inhibitors caused dose-limiting toxicities. Thus, we shifted our focus to ETS1, which is one of the transcription factors that most frequently co-bind Notch-occupied regulatory elements in the T-ALL context. To identify the most essential enhancers, we performed a genome-wide CRISPR interference screen of the strongest ETS1-dependent regulatory elements. The #1-ranked element is located in an intron of AHI1 that interacts with the MYB promoter and is amplified with MYB in ~8.5% of T-ALL patients. Using mouse models, we showed that this enhancer promotes self-renewal of hematopoietic stem cells and T-cell leukemogenesis, maintains early T-cell precursors, and restrains myeloid expansion with aging. We named this enhancer the hematopoietic stem cell MYB enhancer (H-Me). The H-Me shows limited activity and function in committed T-cell progenitors but is accessed during leukemogenesis. In one T-ALL context, ETS1 binds the ETS motif in the H-Me to recruit cBAF to promote chromatin accessibility and activation. ETS1 or cBAF degraders impaired H-Me function. Thus, we identified a targetable stem cell element that is co-opted for T-cell transformation.
Authors
Carea Mullin, Karena Lin, Elizabeth Choe, Cher Sha, Zeel Shukla, Koral Campbell, Anna C. McCarter, Annie Wang, Jannaldo Nieves-Salva, Sarah Khan, Theresa M. Keeley, Shannon Liang, Qing Wang, Ashley F. Melnick, Pearl Evans, Alexander C. Monovich, Ashwin Iyer, Rohan Kodgule, Yamei Deng, Felipe da Veiga Leprevost, Kelly R. Barnett, Petri Pölönen, Rami Khoriaty, Daniel Savic, David T. Teachey, Charles G. Mullighan, Marcin Cieslik, Alexey I. Nesvizhskii, Linda C. Samuelson, Morgan Jones, Qing Li, Russell J.H. Ryan, Mark Y. Chiang
Abstract
Authors
Bowen Yan, Qingchen Yuan, Marco M. Buttigieg, Prabhjot Kaur, Annalisse R. McKee, Daniil E. Shabashvili, Caitlyn Vlasschaert, Alexander G. Bick, Michael J. Rauh, Olga A. Guryanova
Abstract
VEXAS (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) syndrome is a haemato-rheumatoid disease caused by somatic UBA1 mutations in hematopoietic stem cells (HSCs). The pathogenic cell type(s) responsible for the syndrome are unknown and murine models recapitulating the disease are lacking. We report that loss of Uba1 in various mouse hematopoietic cell types resulted in pleiotropic consequences and demonstrate that murine mutants with about 70% loss of Uba1 in neutrophils induced non-lethal VEXAS-like symptoms. Depletion of Uba1 in HSCs induced extensive hematopoietic cell loss while depletion of Uba1 in B or T cells, or in megakaryocytes induced corresponsive cell death but these mutants appeared normal. Depletion of Uba1 in monocytes and neutrophils failed to induce cell death and the mutants were viable. Among the tested models, only depletion of Uba1 in neutrophils induced autoinflammatory symptoms including increased counts and percentage of neutrophils, increased proinflammatory cytokines, occurrence of vacuoles in myeloid cells, splenomegaly and dermatitis. Residual Uba1 was about 30% in the mutant neutrophils, which disrupted cellular hemostasis. Finally, genetic loss of the myeloid pro-survival regulator Morrbid partially mitigated the VEXAS-like symptoms. The established VEXAS-like murine model will assist understanding and treatment of the newly identified autoinflammatory syndrome prevalent among aged men.
Authors
Ge Dong, Jingjing Liu, Wenyan Jin, Hongxi Zhou, Yuchen Wen, Zhiqin Wang, Keyao Xia, Jianlin Zhang, Linxiang Ma, Yunxi Ma, Lorie Chen Cai, Qiufan Zhou, Huaquan Wang, Wei Wei, Ying Fu, Zhigang Cai
Abstract
Platelet hyperreactivity increases the risk of cardiovascular thrombosis in diabetes and failure of antiplatelet drug therapies. Elevated basal and agonist-induced calcium flux is a fundamental cause of platelet hyperreactivity in diabetes; however, the mechanisms responsible for this remain largely unknown. Using a high-sensitivity, unbiased proteomic platform, we consistently detected over 2,400 intracellular proteins and identified proteins that were differentially released by platelets in type 2 diabetes. We identified that SEC61 translocon subunit β (SEC61B) was increased in platelets from humans and mice with hyperglycemia and in megakaryocytes from mice with hyperglycemia. SEC61 is known to act as an endoplasmic reticulum (ER) calcium leak channel in nucleated cells. Using HEK293 cells, we showed that SEC61B overexpression increased calcium flux into the cytosol and decreased protein synthesis. Concordantly, platelets in hyperglycemic mice mobilized more calcium and had decreased protein synthesis. Platelets in both humans and mice with hyperglycemia had increased ER stress. ER stress induced the expression of platelet SEC61B and increased cytosolic calcium. Inhibition of SEC61 with anisomycin decreased platelet calcium flux and inhibited platelet aggregation in vitro and in vivo. These studies demonstrate the existence of a mechanism whereby ER stress–induced upregulation of platelet SEC61B leads to increased cytosolic calcium, potentially contributing to platelet hyperreactivity in diabetes.
Authors
Yvonne X. Kong, Rajan Rehan, Cesar L. Moreno, Søren Madsen, Yunwei Zhang, Huiwen Zhao, Miao Qi, Callum B. Houlahan, Siân P. Cartland, Declan Robertshaw, Vincent Trang, Frederick Jun Liang Ong, Michael Liu, Edward Cheng, Imala Alwis, Alexander Dupuy, Michelle Cielesh, Kristen C. Cooke, Meg Potter, Jacqueline Stöckli, Grant Morahan, Maggie L. Kalev-Zylinska, Matthew T. Rondina, Sol Schulman, Jean Y. H. Yang, G. Gregory Neely, Simone M. Schoenwaelder, Shaun P. Jackson, David E. James, Mary M. Kavurma, Samantha L. Hocking, Stephen M. Twigg, James C. Weaver, Mark Larance, Freda H. Passam
Abstract
SLFN14-related thrombocytopenia is a rare bleeding disorder caused by SLFN14 mutations altering hemostasis in patients with platelet dysfunction. Schlafen (SLFN) proteins are highly conserved in mammals where SLFN14 is specifically expressed in megakaryocyte (MK) and erythroblast lineages. The role of SLFN14 in megakaryopoiesis and platelet function has not been elucidated. We generated a new murine model with a platelet- and MK-specific SLFN14 deletion using platelet factor-4 (PF4) cre-mediated deletion of exons 2 and 3 in Slfn14 (Slfn14;PF4-Cre) to decipher the molecular mechanisms driving the bleeding phenotype. SLFN14;PF4-Cre+ platelets displayed reduced platelet signaling to thrombin, reduced thrombin formation, increased bleeding tendency, and delayed thrombus formation as assessed by intravital imaging. Moreover, fewer in situ bone marrow MKs compared to controls. RNA sequencing and gene ontology analysis of MKs and platelets from Slfn14;PF4-Cre homozygous mice revealed altered pathways of ubiquitination, ATP activity, cytoskeleton and molecular function. In summary, we investigated how SLFN14 deletion in MKs and platelets leads to platelet dysfunction and alters their transcriptome, explaining the platelet dysfunction and bleeding in humans and mice with SLFN14 mutations.
Authors
Rachel J. Stapley, Xenia Sawkulycz, Gabriel H.M. Da Mota Araujo, Maximilian Englert, Lourdes Garcia-Quintanilla, Sophie R.M. Smith, Amna Ahmed, Elizabeth J. Haining, Nayandeep Kaur, Andrea Bacon, Andrey V. Pisarev, Natalie S. Poulter, Dean P.J. Kavanagh, Steven G. Thomas, Samantha J. Montague, Julie Rayes, Zoltan Nagy, Neil V. Morgan
Jab1 promotes immune evasion and progression in acute myeloid leukemia models under oxidative stress
Abstract
Acute myeloid leukemia (AML) is the most common hematological malignancy. Leukemia stem cells exhibit high levels of oxidative stress, with reactive oxygen species (ROS) being the primary products of this stress, inducing the expression of Jab1. Previous studies have demonstrated that Jab1, as a transcriptional coactivator of c-JUN, promotes the malignant progression of AML under oxidative stress. However, its role in immune evasion is still under investigation. Here, we observed that knocking out Jab1 reduced the expression of immune checkpoints in vivo, effectively overcame the immune evasion of AML. Interestingly, the deletion of Jab1 had no impact on the maturation of normal hematopoietic cells in mice. Mechanistically, Jab1 directly activated IGF2BP3 by driving the transcription factor c-JUN, consequently modulated the m6A modification of LILRB4 mRNA and promoted immune evasion in AML. Finally, CSN5i-3 effectively disrupted the signaling pathway mediated by Jab1, thereby restoring cellular immune surveillance and halting the progression of AML. Thus, our results highlight the functional role of Jab1 in supporting AML survival and support the development of targeted therapeutic strategies.
Authors
Nan Zhang, Qian Wang, Guopeng Chen, Li Liu, Zhiying Wang, Linlu Ma, Yuxing Liang, Jinxian Wu, Xinqi Li, Xiaoyan Liu, Fuling Zhou
Abstract
The leukemia fusion gene CBFB-MYH11 requires RUNX1 for leukemogenesis, but the underlying mechanism is unclear. By in vitro studies, we found that CBFβ-SMMHC, the chimeric protein encoded by CBFB-MYH11, could enhance the binding affinity between RUNX1 and its target DNA. Increased RUNX1-DNA binding was also observed in myeloid progenitor cells from mice expressing CBFβ-SMMHC. Moreover, only CBFβ-SMMHC variants able to enhance the DNA binding affinity by RUNX1 could induce leukemia in mouse models. Marked transcriptomic changes, affecting genes associated with inflammatory response and target genes of CBFA2T3, were observed in mice expressing leukemogenic CBFβ-SMMHC variants. Finally, we show that CBFβ-SMMHC could not induce leukemia in mice with a Runx1-R188Q mutation, which reduces RUNX1 DNA binding but not affecting its interaction with CBFβ-SMMHC or its sequestration to cytoplasm by CBFβ-SMMHC. Our data suggest that, in addition to binding RUNX1 to regulate gene expression, enhancing RUNX1 binding affinity to its target DNA is an important mechanism by which CBFβ-SMMHC contributes to leukemogenesis, highlighting RUNX1–DNA interaction as a potential therapeutic target in inv(16) AML.
Authors
Tao Zhen, Yaqiang Cao, Tongyi Dou, Yun Chen, Guadalupe Lopez, Ana Catarina Menezes, Xufeng Wu, John Hammer, Jun Cheng, Lisa Garrett, Stacie Anderson, Martha Kirby, Stephen Wincovitch, Bayu Sisay, Abdel G. Elkahloun, Di Wu, Lucio H. Castilla, Wei Yang, Jiansen Jiang, Keji Zhao, Paul P. Liu
Abstract
The fetal liver is the primary site of hematopoietic stem cell (HSC) generation during embryonic development. However, the molecular mechanisms governing the transition of hematopoiesis from the fetal liver to the bone marrow (BM) remain incompletely understood. Here, we identify the mammalian Polycomb group (PcG) protein Yin Yang 1 (YY1) as a key regulator of this developmental transition. Conditional deletion of Yy1 in the hematopoietic system during fetal development results in neonatal lethality and depletion of the fetal HSC pool. YY1-deficient fetal HSCs exhibit impaired migration and fail to engraft in the adult BM, thereby losing their ability to reconstitute hematopoiesis. Transcriptomic analysis reveals that Yy1 knockout disrupts genetic networks controlling cell motility and adhesion in fetal hematopoietic stem and progenitor cells (HSPCs). Notably, YY1 does not directly bind the promoters of most dysregulated genes. Instead, it modulates chromatin accessibility at regulatory loci, orchestrating broader epigenetic programs essential for HSPC migration and adhesion. Together, these findings establish YY1 as a critical epigenetic regulator of fetal HSC function and provide a mechanistic framework to further decipher how temporal epigenomic configurations determine HSC fetal-to-adult transition during development.
Authors
Sahitya Saka, Zhanping Lu, Yinghua Wang, Peng Liu, Deependra K. Singh, Junki P. Lee, Carmen G. Palii, Tyler R. Alvarez, Anna L. F. V. Assumpção, Xiaona You, Jing Zhang, Marjorie Brand, Michael L. Atchison, Xuan Pan
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)