Hematology
Abstract
The metabolic microenvironment plays important roles in tumorigenesis, but how leukemia-initiating cells (LICs) response to the acidic BM niche remains largely unknown. Here, we show that acid-sensing ion channel 3 (ASIC3) dramatically delays leukemogenesis. Asic3 deletion results in a remarkably enhanced self-renewal, reduced differentiation, and 9-fold greater number of murine acute myeloid LICs. We developed an ultrasensitive, ratiometric, genetically encoded fluorescent pH sensor (pHluorin3) and demonstrated that LICs prefer localizing in the endosteal niche with a neutral pH range of 7.34–7.42, but not in the vascular niche with a lower pH range of 6.89–7.22. Unexpectedly, acid-ASIC3 signaling inhibits both murine and human LIC activities in a noncanonical manner by interacting with the N-terminal of STIM1 to reduce calcium-mediated CAMK1-CREB-MEIS1-LDHA levels, without inducing cation currents. This study reveals a pathway in suppression of leukemogenesis in the acidic BM niche and provides insight into targeting LICs or other cancer stem cells through pH-dependent ASICs.
Authors
Hao Gu, Lietao Weng, Chiqi Chen, Xiaoxin Hao, Rongkun Tao, Xin Qi, Xiaoyun Lai, Ligen Liu, Tinghua Zhang, Yiming Jiang, Jin Wang, Wei-Guang Li, Zhuo Yu, Li Xie, Yaping Zhang, Xiaoxiao He, Ye Yu, Yi Yang, Dehua Wu, Yuzheng Zhao, Tian-Le Xu, Guo-Qiang Chen, Junke Zheng
Abstract
Mitochondrial metabolism orchestrates T cell functions, yet the role of specific mitochondrial components in distinct T cell subsets remains poorly understood. Here, we explored the role of mitochondrial complex II (MC II), the only complex from the electron transport chain (ETC) that plays a role in both ETC and metabolism, in regulating T cell functions. Surprisingly, MC II exerts divergent effects on CD4+ and CD8+ T cell activation and function. Using T cell–specific MC II subunit, succinate dehydrogenase A–deficient (SDHA-deficient) mice, we integrated single-cell RNA-seq and metabolic profiling, with in vitro and in vivo T cell functional assays to illuminate these differences. SDHA deficiency induced metabolic changes and remodeled gene expression exclusively in activated T cells. In CD4+ T cells, SDHA loss dampened both oxidative phosphorylation (OXPHOS) and glycolysis, impaired cytokine production, proliferation, and reduced CD4+ T cell–mediated graft-versus-host disease after allogeneic stem cell transplantation (SCT). In contrast, SDHA deficiency in CD8+ T cells reduced OXPHOS but paradoxically upregulated glycolysis and demonstrated enhanced cytotoxic functions in vitro and in vivo. This metabolic reprogramming endowed SDHA-KO CD8+ T cells with superior in vivo antitumor efficacy after immune checkpoint inhibitor therapy and allogeneic SCT. These findings reveal MC II as a bifurcation point for metabolic and functional specialization in CD4+ and CD8+ T cells.
Authors
Keisuke Seike, Shih-Chun A. Chu, Yuichi Sumii, Takashi Ikeda, Meng-Chih Wu, Laure Maneix, Dongchang Zhao, Yaping Sun, Marcin Cieslik, Pavan Reddy
Abstract
During the progression of acute myeloid leukemia (AML), extramedullary hematopoiesis (EMH) compensates for impaired bone marrow hematopoiesis. However, the specific cellular dynamics of EMH and its influence on AML progression remain poorly understood. In this study, we identified a substantial expansion of the CD81+ erythroblast subpopulation (CD81+ Erys) in the spleens of AML mice, which promoted AML cell proliferation and reduced survival. Mechanistically, CD81+ Erys secrete elevated levels of macrophage migration-inhibitory factor (MIF), which interacted with the CD74 receptor on AML cells, activating the mTORC1 signaling pathway and upregulating Egln3. Consequently, AML cells cocultured with CD81+ Erys exhibited reprogrammed phospholipid metabolism, characterized by an increased phospholipid-to-lysophospholipid ratio. Modulating this metabolic shift, either by supplementing exogenous lysophospholipids or depleting Egln3 in AML cells, restored the phospholipid balance and mitigated the protumorigenic effects induced by CD81+ Erys. Overall, our findings elucidate the molecular crosstalk between erythroblasts and AML cells, extend our insights into the mechanisms driving AML progression, and suggest potential therapeutic strategies.
Authors
Yue Li, Jiaxuan Cao, Jingyuan Tong, Peixia Tang, Haoran Chen, Guohuan Sun, Zining Yang, Xiaoru Zhang, Fang Dong, Shangda Yang, Jie Gao, Xiangnan Zhao, Jinfa Ma, Di Wang, Lei Zhang, Lin Wang, Tao Cheng, Hui Cheng, Lihong Shi
Abstract
Acute myeloid leukemia (AML) is an aggressive cancer with very poor outcomes. To identify additional drivers of leukemogenesis, we analyzed sequencing data from 1,727 unique individual AML patients, which revealed mutations in ubiquitin ligase family genes in 11.2% of adult AML samples with mutual exclusivity. The SKP1/CUL1/F-box (SCF) E3 ubiquitin ligase complex gene, FBXO11, was the most significantly downregulated gene of the SCF complex in AML. We found that FBXO11 interacts with and catalyzes K63-linked ubiquitination of LONP1 in the cytosol, to promote LONP1 entry into mitochondria. We show that depletion of FBXO11 or LONP1 reduces mitochondrial respiration through impaired LONP1 chaperone activity to assemble electron transport chain Complex IV. Reduced mitochondrial respiration secondary to FBXO11 or LONP1 depletion imparted myeloid-biased stem cell properties in primary CD34+ hematopoietic stem and progenitor cells (HSPC) in vitro. In a human xenograft model, depletion of FBXO11 cooperated with AML1-ETO and mutant KRASG12D to generate serially transplantable AML. Our findings suggest that reduced FBXO11 cooperates to initiate AML by priming HSPC for myeloid-biased self-renewal through attenuation of LONP1-mediated regulation of mitochondrial respiration.
Authors
Hayle Kincross, Ya-Chi Angela Mo, Xuan Wang, Linda Chang, Gerben Duns, Franziska Mey, Jihong Jiang, Zurui Zhu, Naomi Isak, Harwood Kwan, Tammy T.Y. Lau, T. Roderick Docking, Pranav Garg, Jessica Tran, Shane Colborne, Se-Wing Grace Cheng, Shujun Huang, Nadia Gharaee, Elijah Willie, Jeremy D.K. Parker, Joshua Bridgers, Davis Wood, Ramon I. Klein Geltink, Gregg B. Morin, Aly Karsan
Abstract
Venous thromboembolism (VTE) is a leading cause of morbidity and mortality, with risk heightened in premenopausal women with obesity or use estrogen-based oral contraceptives. When both risk factors are present, the thrombosis risk increases substantially. Protein S (PS), an essential anticoagulant cofactor, is downregulated by both estrogen and obesity, but the molecular basis for this suppression remains poorly defined. We investigated the effect of estrogen and obesity on PS expression using plasma samples from 157 women stratified by BMI and contraceptive use, alongside 40 mice categorized as lean or obese with or without estrogen pellet treatment. The levels of PS were reduced by either estrogen or obesity alone, and the combined effect increased thrombin generation. In HepG2 hepatocytes, hypoxic conditions (1%–10% O2) mimicking obesity, with or without 17 β-estradiol, suppressed PROS1 transcription and promoter activity. ChIP confirmed direct binding of hypoxia-inducible factor 1α (HIF1α) to the PROS1 promoter, repressing gene expression. These findings define a mechanistic pathway through which estrogen and obesity converge to suppress PS synthesis, providing insight into the elevated thrombosis risk observed in women with obesity using estrogen-based contraceptives.
Authors
Mohammad A. Mohammad, Narender Kumar, Sonali Ghosh, Ashley Paysse, Claudia Leonardi, Vijaya Pilli, Ma Lorena Duhaylungsod, Eric Lazartigues, Diana C. Polania-Villanueva, Sadaf Nouman, Logan A. Barrios, Rima Chattopadhyay, Rafika Yasmin, Alaina Guilbeau, Manoj Kumar, Tina Nguyen, Jovanny Zabaleta, Li Li, Luis Del Valle, Mallory T. Barbier, Samarpan Majumder, Laurent O. Mosnier, Rinku Majumder
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
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)