bims-scepro Biomed News
on Stem cell proteostasis
Issue of 2025–01–26
25 papers selected by
William Grey, University of York
  1. FLT3 is genetically essential for ITD-mutated leukemic stem cells but dispensable for human hematopoietic stem cells.
  2. Single-cell DNA sequencing reveals pervasive positive selection throughout preleukemic evolution.
  3. Metabolism and metabolites regulating hematopoiesis.
  4. Secreted Frizzled-Related Protein 1a regulates hematopoietic development in a dose-dependent manner.
  5. Prenatal exposure to chemotherapy increases the mutation burden in human neonatal hematopoietic stem cells.
  6. Repurposing the prostaglandin analogue treprostinil and the calcium-sensing receptor modulator cinacalcet to revive cord blood as an alternate source of hematopoietic stem and progenitor cells for transplantation.
  7. NR2F6 regulates stem cell hematopoiesis and myelopoiesis in mice.
  8. GATA2 links stemness to chemotherapy resistance in acute myeloid leukemia.
  9. Coordinated immune networks in leukemia bone marrow microenvironments distinguish response to cellular therapy.
  10. CD44-Mediated Metabolic Rewiring is A Targetable Dependency of IDH-Mutant Leukemia.
  11. Investigating resistance to 5-Azacytidine and Venetoclax in PDX models of MDS/AML.
  12. H2-K1 protects murine MLL-AF9 leukemia stem cells from natural killer cell-mediated immune surveillance.
  13. Sex dimorphism in the mouse bone marrow niche regulates hematopoietic engraftment via sex-specific Kdm5c/Cxcl12 signaling.
  14. Harnessing the ubiquitin proteasome system as a key player in stem cell biology.
  15. In vitro ILC differentiation from human HSCs.
  16. Mitochondrial protein import stress.
  17. Redox proteomics reveal a role for peroxiredoxinylation in stress protection.
  18. Palmitoylation-dependent regulation of GPX4 suppresses ferroptosis.
  19. Two-layered immune escape in AML is overcome by Fcγ receptor activation and inhibition of PGE2 signaling in NK cells.
  20. Transcriptional responses to prolonged oxidative stress require cholinergic activation of G-protein-coupled receptor signaling.
  21. Insights into the role of phosphorylation on microtubule crosslinking by PRC1.
  22. Aurora B controls microtubule stability to regulate abscission dynamics in stem cells.
  23. Myeloablative conditioning in cord blood transplantation for acute myeloid leukemia patients is efficacious only until age 55.
  24. CM313 Monotherapy in Patients With Relapsed/Refractory Multiple Myeloma or Marginal Zone Lymphoma: A Multicenter, Phase 1 Dose-Escalation and Dose-Expansion Trial.
  25. In Situ Mechanics of the Cytoskeleton.
  1. Blood. 2025 Jan 22. pii: blood.2024025886. [Epub ahead of print]
    FLT3 is genetically essential for ITD-mutated leukemic stem cells but dispensable for human hematopoietic stem cells.
    Joana L Araújo, Elvin Wagenblast, Veronique Voisin, Jessica McLeod, Olga I Gan, Suraj Bansal, Liqing Jin, Amanda Mitchell, Blaise Gratton, Sarah Kristen Cutting, Andrea Arruda, Monica Doedens, Anthea Travas, Dennis Dong Hwan Kim, Jose-Mario Capo-Chichi, Sagi Abelson, Mark D Minden, Jean Cy Wang, Manuel A Sobrinho-Simões, Perpétua Pinto-do-Ó, Eric R Lechman, John E Dick.
      Leukemic stem cells (LSCs) fuel acute myeloid leukemia (AML) growth and relapse, but therapies tailored towards eradicating LSCs without harming normal hematopoietic stem cells (HSCs) are lacking. FLT3 is considered an important therapeutic target due to frequent mutation in AML and association with relapse. However, there has been limited clinical success with FLT3 drug targeting, suggesting either that FLT3 is not a vulnerability in LSC, or that more potent inhibition is required, a scenario where HSC toxicity could become limiting. We tested these possibilities by ablating FLT3 using CRISPR/Cas9-mediated FLT3 knock-out (FLT3-KO) in human LSCs and HSCs followed by functional xenograft assays. FLT3-KO in LSCs from FLT3-ITD mutated, but not FLT3-wild type (WT) AMLs, resulted in short-term leukemic grafts of FLT3-KO edited cells that disappeared by 12 weeks. By contrast, FLT3-KO in HSCs from fetal liver, cord blood and adult bone marrow did not impair multilineage hematopoiesis in primary and secondary xenografts. Our study establishes FLT3 as an ideal therapeutic target where ITD+ LSC are eradicated upon FLT3 deletion, while HSCs are spared. These findings support the development of more potent FLT3-targeting drugs or gene-editing approaches for LSC eradication to improve clinical outcomes.
    DOI:  https://doi.org/10.1182/blood.2024025886
  2. Cell Genom. 2025 Jan 16. pii: S2666-979X(24)00373-2. [Epub ahead of print] 100744
    Single-cell DNA sequencing reveals pervasive positive selection throughout preleukemic evolution.
    Gladys Poon, Aditi Vedi, Mathijs Sanders, Elisa Laurenti, Peter Valk, Jamie R Blundell.
      The representation of driver mutations in preleukemic hematopoietic stem cells (pHSCs) provides a window into the somatic evolution that precedes acute myeloid leukemia (AML). Here, we isolate pHSCs from the bone marrow of 16 patients diagnosed with AML and perform single-cell DNA sequencing on thousands of cells to reconstruct phylogenetic trees of the major driver clones in each patient. We develop a computational framework that can infer levels of positive selection operating during preleukemic evolution from the statistical properties of these phylogenetic trees. Combining these data with 67 previously published phylogenetic trees, we find that the highly variable structures of preleukemic trees emerge naturally from a simple model of somatic evolution with pervasive positive selection typically in the range of 9%-24% per year. At these levels of positive selection, we show that the identification of early multiple-mutant clones could be used to identify individuals at risk of future AML.
    Keywords:  acute myeloid leukemia; cancer evolution; clonal hematopoiesis; early detection; evolutionary dynamics; pre-cancer; somatic mutation
    DOI:  https://doi.org/10.1016/j.xgen.2024.100744
  3. Curr Opin Immunol. 2025 Jan 18. pii: S0952-7915(25)00001-9. [Epub ahead of print]93 102525
    Metabolism and metabolites regulating hematopoiesis.
    Baihao Zhang, Sidonia Fagarasan.
      Energy metabolism of immune cells, such as glycolysis and mitochondrial activity, requires strict regulation. This is especially critical in the complex environment of the bone marrow (BM), where there is a need to both preserve the quiescence of hematopoietic stem cells (HSCs) and guarantee timed and effective lineage differentiation of the HSCs. Recent advances highlight the critical roles played by bioactive metabolites in regulating hematopoiesis. In particular, secreted immune metabolites (SIMets), such as γ-aminobutyric acid (GABA) and acetylcholine, secreted by B-lineage cells, act as potent modulators of hematopoietic processes, influencing HSC differentiation and emergency hematopoiesis. In this review, we provide an overview and discuss mechanisms by which energy metabolism and SIMets regulate hematopoiesis. We propose that biochemical communication facilitated by these metabolites is essential for maintaining the BM niche and suggest potential therapeutic strategies using SIMets in hematological disorders.
    DOI:  https://doi.org/10.1016/j.coi.2025.102525
  4. bioRxiv. 2025 Jan 10. pii: 2025.01.10.632371. [Epub ahead of print]
    Secreted Frizzled-Related Protein 1a regulates hematopoietic development in a dose-dependent manner.
    Amber D Ide, Kelsey A Carpenter, Mohamed Elaswad, Katherine Opria, Kendersley Marcellin, Carla Gilliland, Stephanie Grainger.
      Hematopoietic stem and progenitor cells (HSPCs) arise only during embryonic development, and their identity specification, emergence from the floor of the dorsal aorta, and proliferation are all tightly regulated by molecular mechanisms such as signaling cues. Among these, Wnt signaling plays an important role in HSPC specification, differentiation, and self-renewal, requiring precise modulation for proper development and homeostasis. Wnt signaling is initiated when a Wnt ligand binds to cell surface receptors such as those encoded by the frizzled gene family, activating intracellular signaling pathways that regulate gene expression. Secreted frizzled-related proteins (Sfrps) are known modulators of Wnt signaling, acting as both agonists and antagonists of this pathway. Yet, in vivo functions of Sfrps in HSPC development remain incompletely understood. Here, we demonstrate that Sfrp1a regulates zebrafish HSPC development and differentiation in a dose-dependent manner. In Sfrp1a loss of function animals, we observe an increase in HSPCs, an upregulation of canonical Wnt signaling, and a decrease in differentiation into both lymphoid and myeloid lineages. Conversely, at low-dose sfrp1a overexpression, there is a decrease in HSPCs and an increase in lymphoid differentiation. High-dose sfrp1a overexpression phenocopies the loss of function animals, with an increase in HSPCs, increased canonical Wnt signaling, and decreased lymphoid and myeloid differentiation. These findings highlight the importance of dose-dependent modulation of Sfrps, paralleling what is observed in hematopoietic cancers where SFRP1 loss-of-function and gain-of-function variants can drive tumorigenesis.
    One sentence summary: Sfrp1a is required for hematopoietic stem cell development.
    DOI:  https://doi.org/10.1101/2025.01.10.632371
  5. Cancer Discov. 2025 Jan 24.
    Prenatal exposure to chemotherapy increases the mutation burden in human neonatal hematopoietic stem cells.
    Ilana Struys, Carolina Velázquez, Joske Ubels, Charlotte L LeJeune, Markus J van Roosmalen, Axel K M Rosendahl Huber, Anais J C N van Leeuwen, Wouter Bossuyt, Bernard Thienpont, Thierry Voet, Kristel Van Calsteren, Liesbeth Lenaerts, Ruben van Boxtel, Frédéric Amant.
      Chemotherapy is included in the standard of care for cancer treatment during pregnancy. However, whether prenatal exposure to maternal chemotherapy treatment has a mutagenic impact on the fetal genome, remains unexplored. Therefore, we investigated mutation accumulation in hematopoietic stem and progenitor cells (HSPCs) from neonates born to pregnant cancer patients treated with chemotherapy, as well as healthy pregnant women and untreated pregnant cancer patients. The mutational burden in HSPCs from neonates born to untreated pregnant cancer patients and to healthy controls was similar, but increased after prenatal exposure to varying types of chemotherapy regimens. Mutational signature analyses attributed the excess mutations to clock-like processes, which are active during normal cellular aging, or to direct mutagenesis by platinum-based drugs in neonates prenatally exposed to platinum-containing regimens. Our findings in the neonatal hematopoietic compartment are consistent with mutational signatures previously identified in cells of cancer survivors directly exposed to these chemotherapeutic drugs.
    DOI:  https://doi.org/10.1158/2159-8290.CD-24-1368
  6. Front Pharmacol. 2024 ;15 1444311
    Repurposing the prostaglandin analogue treprostinil and the calcium-sensing receptor modulator cinacalcet to revive cord blood as an alternate source of hematopoietic stem and progenitor cells for transplantation.
    Michaela Prchal-Murphy, Julia Zehenter, Marlene Fischer, Anita Pirabe, Madeleine Themanns, Behnaz Afrashteh, Eva Maria Putz, Karoline Kollmann, José Basílio, Manuel Salzmann, Wolfgang Strohmaier, Günther Krumpl, Alex Farr, Veronika Sexl, Michael Freissmuth, Eva Zebedin-Brandl.
       Objective: The expanding field of hematopoietic cell transplantation (HCT) for non-malignant diseases, including those amenable to gene therapy or gene editing, faces challenges due to limited donor availability and the toxicity associated with cell collection methods. Umbilical cord blood (CB) represents a readily accessible source of hematopoietic stem and progenitor cells (HSPCs); however, the cell dose obtainable from a single cord blood unit is frequently insufficient. This limitation can be addressed by enhancing the potency of HSPCs, specifically their capacity to reconstitute hematopoiesis. In our study, we investigated the combined effects of treprostinil, a prostaglandin analog, and cinacalcet, a calcium-sensing receptor modulator, on the reconstitution of hematopoiesis.
    Methods: A Lineage Cell Depletion Kit was employed to isolate lineage-negative (lin-) HSPCs from mouse bone marrow. A Human CB CD34 Positive Selection Kit was utilized to isolate CD34+ cells from the CB of healthy donors. In vitro, the effects of treprostinil, cinacalcet, and their combination on the migration, adhesion, and differentiation of HSPCs were assessed. In vivo, homing and engraftment were examined. Eight-week-old female and male C57BL/6J, BALB/c, or female NSG mice served as recipient models.
    Results: When administered concomitantly, treprostinil and cinacalcet exhibited mutual antagonism: the survival of recipient animals was lower when both drugs were administered together compared to either agent alone. Conversely, a sequential regimen involving priming with treprostinil/forskolin followed by cinacalcet treatment in vivo enhanced survival, irrespective of whether hematopoiesis was reconstituted by human or murine HSPCs. In vitro assays demonstrated enhanced migration and adhesion in response to the presence of treprostinil and cinacalcet, suggesting potential synergistic effects. Colony formation confirmed synergism.
    Conclusion: Augmenting the bone marrow reconstitution potential of HSPCs with treprostinil and cinacalcet shows promise for rescuing patients undergoing HCT. This approach is particularly beneficial for those patients at high risk of transplant failure due to limited numbers of available HSPCs. Furthermore, enhancing the potency of HSPCs has the potential to alleviate the burden and risks associated with HSPC donation, as it would reduce the number of cells needed for collection.
    Keywords:  CD34+ HSPCs; bone marrow reconstitution; cord blood; differentiation; drug repurposing; engraftment efficiency; stem cell transplantation
    DOI:  https://doi.org/10.3389/fphar.2024.1444311
  7. Front Immunol. 2024 ;15 1404805
    NR2F6 regulates stem cell hematopoiesis and myelopoiesis in mice.
    Johannes Woelk, Hamsa Narasimhan, Christa Pfeifhofer-Obermair, Barbara U Schraml, Natascha Hermann-Kleiter.
      Nuclear receptors regulate hematopoietic stem cells (HSCs) and peripheral immune cells in mice and humans. The nuclear orphan receptor NR2F6 (EAR-2) has been shown to control murine hematopoiesis. Still, detailed analysis of the distinct stem cell, myeloid, and lymphoid progenitors in the bone marrow in a genetic loss of function model remains pending. In this study, we found that adult germline Nr2f6-deficient mice contained increased percentages of total long-term and short-term HSCs, as well as a subpopulation within the lineage-biased multipotent progenitor (MPP3) cells. The loss of NR2F6 thus led to an increase in the percentage of LSK+ cells. Following the differentiation from the common myeloid progenitors (CMP), the granulocyte-monocyte progenitors (GMP) were decreased, while monocyte-dendritic progenitors (MDP) were increased in Nr2f6-deficient bone marrow. Within the pre-conventional dendritic progenitors (pre-cDCs), the subpopulation of pre-cDC2s was reduced in the bone marrow of Nr2f6-deficient mice. We did not observe differences in the development of common lymphoid progenitor populations. Our findings contrast previous studies but underscore the role of NR2F6 in regulating gene expression levels during mouse bone marrow hematopoiesis and myelopoiesis.
    Keywords:  GMP; HSC; MDP; bone marrow; hematopoiesis; myeloid compartment; nuclear receptor NR2F6; pre-cDC2
    DOI:  https://doi.org/10.3389/fimmu.2024.1404805
  8. Blood. 2025 Jan 22. pii: blood.2024025761. [Epub ahead of print]
    GATA2 links stemness to chemotherapy resistance in acute myeloid leukemia.
    Fatemeh Alikarami, Hongbo M Xie, Simone S Riedel, Haley Goodrow, Declan Raymond Barrett, Leila Mahdavi, Alexandra Lenard, Changya Chen, Taylor Yamauchi, Etienne Danis, Zhendong Cao, Vu Le-Huy Tran, Mabel Minji Jung, Yapeng Li, Hua Huang, Junwei Shi, Kai Tan, David Trent Teachey, Emery H Bresnick, Tobias Neff, Kathrin Maria Bernt.
      Stemness-associated cell states are linked to chemotherapy resistance in AML. We uncovered a direct mechanistic link between expression of the stem cell transcription factor GATA2 and drug resistance. The GATA-binding protein 2 (GATA2) plays a central role in blood stem cell generation and maintenance. We find substantial intra- and inter-patient variability in GATA2 expression across AML patient samples. GATA2 expression varies by molecular subtype and has been linked to outcome. In a murine model, KMT2A-MLL3 driven AML originating from a stem cell or immature progenitor cell population have higher Gata2 expression and are more resistant to the standard AML chemotherapy agent doxorubicin. Deletion of Gata2 resulted in more robust induction of p53 following exposure to doxorubicin. ChIP-Seq, RNA-Seq and functional studies revealed that GATA2 regulates the expression of RASSF4, a modulator of the p53 inhibitor MDM2. GATA2 and RASSF4 are anti-correlated in human cell lines and AML patient cell bulk and single cell expression datasets. Knockdown of Rassf4 in Gata2 low cells resulted in doxorubicin or nutlin-3 resistance. Conversely, overexpression of Rassf4 results in sensitization of cells expressing high levels of Gata2. Finally, doxorubicin and nutlin-3 are synergistic in Gata2-high murine AML, as well as AML patient samples. We discovered a previously unappreciated role for GATA2 in dampening p53-mediated apoptosis via transcriptional regulation of RASSF4, a modulator of MDM2. This role for GATA2 directly links the expression of a stemness associated transcription factor to chemotherapy resistance.
    DOI:  https://doi.org/10.1182/blood.2024025761
  9. Sci Immunol. 2025 Jan 24. 10(103): eadr0782
    Coordinated immune networks in leukemia bone marrow microenvironments distinguish response to cellular therapy.
    Katie Maurer, Cameron Y Park, Shouvik Mani, Mehdi Borji, Florian Raths, Kenneth H Gouin, Livius Penter, Yinuo Jin, Jia Yi Zhang, Crystal Shin, James R Brenner, Jackson Southard, Sachi Krishna, Wesley Lu, Haoxiang Lyu, Domenic Abbondanza, Chanell Mangum, Lars Rønn Olsen, Michael J Lawson, Martin Fabani, Donna S Neuberg, Pavan Bachireddy, Eli N Glezer, Samouil L Farhi, Shuqiang Li, Kenneth J Livak, Jerome Ritz, Robert J Soiffer, Catherine J Wu, Elham Azizi.
      Understanding how intratumoral immune populations coordinate antitumor responses after therapy can guide treatment prioritization. We systematically analyzed an established immunotherapy, donor lymphocyte infusion (DLI), by assessing 348,905 single-cell transcriptomes from 74 longitudinal bone marrow samples of 25 patients with relapsed leukemia; a subset was evaluated by both protein- and transcriptome-based spatial analysis. In acute myeloid leukemia (AML) DLI responders, we identified clonally expanded ZNF683+ CD8+ cytotoxic T lymphocytes with in vitro specificity for patient-matched AML. These cells originated primarily from the DLI product and appeared to coordinate antitumor immune responses through interaction with diverse immune cell types within the marrow microenvironment. Nonresponders lacked this cross-talk and had cytotoxic T lymphocytes with elevated TIGIT expression. Our study identifies recipient bone marrow microenvironment differences as a determinant of an effective antileukemia response and opens opportunities to modulate cellular therapy.
    DOI:  https://doi.org/10.1126/sciimmunol.adr0782
  10. Blood. 2025 Jan 22. pii: blood.2024027207. [Epub ahead of print]
    CD44-Mediated Metabolic Rewiring is A Targetable Dependency of IDH-Mutant Leukemia.
    Junhua Lyu, Yuxuan Liu, Ningning Liu, Hieu Vu, Feng Cai, Hui Cao, Pranita Kaphle, Zheng Wu, Giovanni A Botten, Yuannyu Zhang, Jin Wang, Sarada Achyutuni, Xiaofei Gao, Ilaria Iacobucci, Charles G Mullighan, Stephen S Chung, Min Ni, Ralph J DeBerardinis, Jian Xu.
      Recurrent IDH mutations catalyze NADPH-dependent production of oncometabolite R-2HG for tumorigenesis. IDH inhibition provides clinical response in a subset of acute myeloid leukemia (AML) cases; however, most patients develop resistance, highlighting the need for more effective IDH-targeting therapies. By comparing transcriptomic alterations in isogenic leukemia cells harboring CRISPR base-edited IDH mutations, we identify the activation of adhesion molecules including CD44, a transmembrane glycoprotein, as a shared feature of IDH-mutant leukemia, consistent with elevated CD44 expression in IDH-mutant AML patients. CD44 is indispensable for IDH-mutant leukemia cells through activating pentose phosphate pathway and inhibiting glycolysis by phosphorylating G6PD and PKM2, respectively. This metabolic rewiring ensures efficient NADPH generation for mutant IDH-catalyzed R-2HG production. Combining IDH inhibition with CD44 blockade enhances the elimination of IDH-mutant leukemia cells. Hence, we describe an oncogenic feedforward pathway involving CD44-mediated metabolic rewiring for oncometabolite production, representing a targetable dependency of IDH-mutant malignancies.
    DOI:  https://doi.org/10.1182/blood.2024027207
  11. Front Oncol. 2024 ;14 1414950
    Investigating resistance to 5-Azacytidine and Venetoclax in PDX models of MDS/AML.
    Petra Bašová, Lubomír Minařík, Silvia Carina Magalhaes-Novais, Jana Balounová, Zuzana Zemanová, Tatiana Aghová, Martin Špaček, Anna Jonášová, Kristýna Gloc Pimková, Jan Procházka, Radislav Sedláček, Tomáš Stopka.
       Introduction: Progressing myelodysplastic syndrome (MDS) into acute myeloid leukemia (AML) is an indication for hypomethylating therapy (HMA, 5-Azacytidine (AZA)) and a BCL2 inhibitor (Venetoclax, VEN) for intensive chemotherapy ineligible patients. Mouse models that engraft primary AML samples may further advance VEN + AZA resistance research.
    Methods: We generated a set of transplantable murine PDX models from MDS/AML patients who developed resistance to VEN + AZA and compared the differences in hematopoiesis of the PDX models with primary bone marrow samples at the genetic level. PDX were created in NSGS mice via intraosseal injection of luciferase-encoding Lentivirus-infected MDS/AML primary cells from patient bone marrow. We validated the resistance of PDX-leukemia to VEN and AZA and further tested candidate agents that inhibit the growth of VEN/AZA-resistant AML.
    Results and discussion: Transplantable PDX models for MDS/AML arise with 31 % frequency. The lower frequency of transplantable PDX models is not related to peritransplant lethality of the graft, but rather to the loss of the ability of short-term proliferation of leukemic progenitors after 10 weeks of engraftment. There exist subtle genetic and cytological changes between primary and PDX-AML samples however, the PDX models retain therapy resistance observed in patients. Based on in vitro testing and in vivo validation in PDX models, Panobinostat and Dinaciclib are very promising candidate agents that overcome dual VEN + AZA resistance.
    Keywords:  5-Azacytidine; PDX (patient derived xenograft); Venetoclax (BCL2 inhibitor); myelodysplastic syndrome; therapeutic targets
    DOI:  https://doi.org/10.3389/fonc.2024.1414950
  12. Haematologica. 2025 01 23.
    H2-K1 protects murine MLL-AF9 leukemia stem cells from natural killer cell-mediated immune surveillance.
    Lymphoid Development and Regulation
      Not available.
    DOI:  https://doi.org/10.3324/haematol.2024.286468
  13. J Clin Invest. 2025 Jan 21. pii: e182125. [Epub ahead of print]
    Sex dimorphism in the mouse bone marrow niche regulates hematopoietic engraftment via sex-specific Kdm5c/Cxcl12 signaling.
    Xiaojing Cui, Liming Hou, Bowen Yan, Jinpeng Liu, Cuiping Zhang, Pinpin Sui, Sheng Tong, Larry Luchsinger, Avital Mendelson, Daohong Zhou, Feng-Chun Yang, Hui Zhong, Ying Liang.
      The bone marrow (BM) niche is critical in regulating hematopoiesis, and sexual dimorphism and its underlying mechanism in BM niche and its impact on hematopoiesis are not well understood. We show that male mice exhibited a higher abundance of leptin-receptor-expressing mesenchymal stromal cells (LepR-MSCs) compared to female mice. Sex-mismatched co-culture and BM transplantation showed that the male BM niche provided superior support for in vitro colony formation and in vivo hematopoietic engraftment. The co-transplantation of male stromal cells significantly enhanced engraftment in female recipients. Single-cell RNA sequencing revealed that the lower expression of the X-linked lysine H3K4 demethylase, Kdm5c, in male MSCs led to the increased expression of Cxcl12. In MSC-specific Kdm5c knockout mouse model, the reduction of KDM5C in female MSCs enhanced MSC quantity and function, ultimately improving engraftment to the male level. Kdm5c thus plays a role in driving sexual dimorphism in the BM niche and hematopoietic regeneration. Our study unveils a sex-dependent mechanism governing BM niche regulation and its impact on hematopoietic engraftment. The finding offers potential implications for enhancing BM transplantation efficacy in clinical settings by harnessing the resource of male MSCs or targeting Kdm5c.
    Keywords:  Stem cell transplantation; Stem cells; Transplantation
    DOI:  https://doi.org/10.1172/JCI182125
  14. Biofactors. 2025 Jan-Feb;51(1):51(1): e2157
    Harnessing the ubiquitin proteasome system as a key player in stem cell biology.
    Hind Atta, Dina H Kassem, Mohamed M Kamal, Nadia M Hamdy.
      Intracellular proteins take part in almost every body function; thus, protein homeostasis is of utmost importance. The ubiquitin proteasome system (UPS) has a fundamental role in protein homeostasis. Its main role is to selectively eradicate impaired or misfolded proteins, thus halting any damage that could arise from the accumulation of these malfunctioning proteins. Proteasomes have a critical role in controlling protein homeostasis in all cell types, including stem cells. We will discuss the role of UPS enzymes as well as the 26S proteasome complex in stem cell biology from several angles. First, we shall overview common trends of proteasomal activity and gene expression of different proteasomal subunits and UPS enzymes upon passaging and differentiation of stem cells toward various cell lineages. Second, we shall explore the effect of modulating proteasomal activity in stem cells and navigate through the interrelation between proteasomes' activity and various proteasome-related transcription factors. Third, we will shed light on curated microRNAs and long non-coding RNAs using various bioinformatics tools that might have a possible role in regulating UPS in stem cells and possibly, upon manipulation, can enhance the differentiation process into different lineages and/or delay senescence upon cell passaging. This will help to decipher the role played by individual UPS enzymes and subunits as well as various interrelated molecular mediators in stem cells' maintenance and/or differentiation and open new avenues in stem cell research. This can ultimately provide a leap toward developing novel therapeutic interventions related to proteasome dysregulation.
    Keywords:  26S proteasome complex; differentiation; embryonic stem cells; mesenchymal stem cells; pluripotency; proteostasis; senescence; targeted protein degradation and regenerative medicine; ubiquitin proteasome system
    DOI:  https://doi.org/10.1002/biof.2157
  15. Methods Cell Biol. 2025 ;pii: S0091-679X(24)00213-9. [Epub ahead of print]191 41-57
    In vitro ILC differentiation from human HSCs.
    Silvia Santopolo, Cecilia Ciancaglini, Francesca Romana Mariotti, Lorenzo Moretta, Linda Quatrini.
      The Innate Lymphoid Cells (ILCs) are a family of innate immune cells composed by the Natural Killer (NK) cells and the helper ILCs (hILCs) (ILC1, ILC2, ILC3), both developing from a common ILC precursor (ILCP) derived from hematopoietic stem cells (HSCs). A correct ILC reconstitution is crucial, particularly in patients receiving HSC transplantation (HSCT), the only therapeutic option for many adult and pediatric high-risk hematological malignancies. Indeed, mainly thanks to their cytotoxic activity, NK cells have a strong Graft-versus-Leukemia (GvL) effect. On the other hand, hILCs, that are mainly tissue resident, are involved in tissue repair and homeostasis, Graft-versus-Host Disease (GvHD) prevention and immune response to infections. Unlike NK cell development, hILC-poiesis is still poorly characterized in humans. Here, we provide a protocol for the in vitro ILC differentiation from healthy donor peripheral blood-derived CD34+ HSCs. This could represent a useful model to dissect the molecular mechanisms by which the distinct ILC subsets are generated from ILCP leading to the development of novel strategies to improve the HSCT clinical outcome.
    Keywords:  Differentiation; HSCT; Hematological malignancies; Hematopoietic stem cells; Innate lymphoid cells; NK cells
    DOI:  https://doi.org/10.1016/bs.mcb.2024.10.004
  16. Nat Cell Biol. 2025 Jan 22.
    Mitochondrial protein import stress.
    Nikolaus Pfanner, Fabian den Brave, Thomas Becker.
      Mitochondria have to import a large number of precursor proteins from the cytosol. Chaperones keep these proteins in a largely unfolded state and guide them to the mitochondrial import sites. Premature folding, mitochondrial stress and import defects can cause clogging of import sites and accumulation of non-imported precursors, representing a critical burden for cellular proteostasis. Here we discuss how cells respond to mitochondrial protein import stress by regenerating clogged import sites and inducing stress responses. The mitochondrial protein import machinery has a dual role by serving as sensor for detecting mitochondrial dysfunction and inducing stress-response pathways. The production of chaperones that fold or sequester precursor proteins in deposits is induced and the proteasomal activity is increased to remove the excess precursor proteins. Together, these pathways reveal how mitochondria are tightly integrated into a cellular proteostasis and stress response network to maintain cell viability.
    DOI:  https://doi.org/10.1038/s41556-024-01590-w
  17. Cell Rep. 2025 Jan 21. pii: S2211-1247(24)01575-4. [Epub ahead of print]44(2): 115224
    Redox proteomics reveal a role for peroxiredoxinylation in stress protection.
    Gerhard Seisenbacher, Zrinka Raguz Nakic, Eva Borràs, Eduard Sabidó, Uwe Sauer, Eulalia de Nadal, Francesc Posas.
      The redox state of proteins is essential for their function and guarantees cell fitness. Peroxiredoxins protect cells against oxidative stress, maintain redox homeostasis, act as chaperones, and transmit hydrogen peroxide signals to redox regulators. Despite the profound structural and functional knowledge of peroxiredoxins action, information on how the different functions are concerted is still scarce. Using global proteomic analyses, we show here that the yeast peroxiredoxin Tsa1 interacts with many proteins of essential biological processes, including protein turnover and carbohydrate metabolism. Several of these interactions are of a covalent nature, and we show that failure of peroxiredoxinylation of Gnd1 affects its phosphogluconate dehydrogenase activity and impairs recovery upon stress. Thioredoxins directly remove TSA1-formed mixed disulfide intermediates, thus expanding the role of the thioredoxin-peroxiredoxin redox cycle pair to buffer the redox state of proteins.
    Keywords:  CP: Molecular biology; Tsa1; oxidative stress; peroxiredoxins; redox biology; stress
    DOI:  https://doi.org/10.1016/j.celrep.2024.115224
  18. Nat Commun. 2025 Jan 20. 16(1): 867
    Palmitoylation-dependent regulation of GPX4 suppresses ferroptosis.
    Bin Huang, Hui Wang, Shuo Liu, Meng Hao, Dan Luo, Yi Zhou, Ying Huang, Yong Nian, Lei Zhang, Bo Chu, Chengqian Yin.
      S-palmitoylation is a reversible and widespread post-translational modification, but its role in the regulation of ferroptosis has been poorly understood. Here, we elucidate that GPX4, an essential regulator of ferroptosis, is reversibly palmitoylated on cysteine 66. The acyltransferase ZDHHC20 palmitoylates GPX4 and increases its protein stability. ZDHHC20 depletion or inhibition of protein palmitoylation by 2-BP sensitizes cancer cells to ferroptosis. Moreover, we identify APT2 as the depalmitoylase of GPX4. Genetic silencing or pharmacological inhibition of APT2 with ML349 increases GPX4 palmitoylation, thereby stabilizing the protein and conferring resistance to ferroptosis. Notably, disrupting GPX4 palmitoylation markedly potentiates ferroptosis in xenografted and orthotopically implanted tumor models, and inhibits tumor metastasis through blood vessels. In the chemically induced colorectal cancer model, knockout of APT2 significantly aggravates cancer progression. Furthermore, pharmacologically modulating GPX4 palmitoylation impacts liver ischemia-reperfusion injury. Overall, our findings uncover the intricate network regulating GPX4 palmitoylation, highlighting its pivotal role in modulating ferroptosis sensitivity.
    DOI:  https://doi.org/10.1038/s41467-025-56344-5
  19. Blood. 2025 Jan 21. pii: blood.2024025706. [Epub ahead of print]
    Two-layered immune escape in AML is overcome by Fcγ receptor activation and inhibition of PGE2 signaling in NK cells.
    Charlotte Rothfuß, Tobias Baumann, Sainitin Donakonda, Bettina Brauchle, Anetta Marcinek, Christian Urban, Julia Mergner, Anna-Marie Pedde, Anna Hirschberger, Christina Krupka, Anne-Sophie Neumann, Gerulf Hänel, Camilla Merten, Rupert Öllinger, Judith S Hecker, Tanja Bauer, Christian Rudolf Schmid, Katharina S Götze, Jennifer Altomonte, Veit L Bücklein, Roland Jacobs, Roland Rad, Corinna Dawid, Luca Simeoni, Burkhart Schraven, Andreas Pichlmair, Marion Subklewe, Percy Alexander Knolle, Jan P Böttcher, Bastian Höchst.
      Loss of anticancer NK cell function in AML patients is associated with fatal disease progression and remains poorly understood. Here, we demonstrate that AML-blasts isolated from patients rapidly inhibit NK cell function and escape NK cell-mediated killing. Transcriptome analysis of NK cells exposed to AML-blasts revealed increased CREM expression and transcriptional activity, indicating enhanced cAMP signalling, confirmed by uniform production of the cAMP-inducing prostanoid PGE2 by all AML-blast isolates from patients. Phosphoproteome analysis disclosed that PGE2 induced a blockade of LCK-ERK signalling that is crucial for NK cell activation, indicating a two-layered escape of AML-blasts with low expression of NK cell-activating ligands and inhibition of NK cell signalling. To evaluate the therapeutic potential to target PGE2 inhibition, we combined Fcg-receptor-mediated activation with the prevention of inhibitory PGE2-signalling. This rescued NK cell function and restored the killing of AML-blasts. Thus, we identify the PGE2-LCK signalling axis as the key barrier for NK cell activation in two-layered immune escape of AML-blasts that can be targeted for immune therapy to reconstitute anti-cancer NK cell immunity in AML patients.
    DOI:  https://doi.org/10.1182/blood.2024025706
  20. bioRxiv. 2025 Jan 07. pii: 2025.01.06.628021. [Epub ahead of print]
    Transcriptional responses to prolonged oxidative stress require cholinergic activation of G-protein-coupled receptor signaling.
    Kasturi Biswas, Caroline Moore, Hannah Rogers, Khursheed A Wani, Read Pukkila-Worley, Daniel P Higgins, Amy K Walker, James B Rand, Michael M Francis.
      Organisms have evolved protective strategies that are geared toward limiting cellular damage and enhancing organismal survival in the face of environmental stresses, but how these protective mechanisms are coordinated remains unclear. Here, we define a requirement for neural activity in mobilizing the antioxidant defenses of the nematode Caenorhabditis elegans both during prolonged oxidative stress and prior to its onset. We show that acetylcholine-deficient mutants are particularly vulnerable to prolonged oxidative stress. We find that prolonged oxidative stress mobilizes a broad transcriptional response which is strongly dependent on both cholinergic signaling and activation of the muscarinic G-protein acetylcholine coupled receptor (mAChR) GAR-3. Gene enrichment analysis revealed a lack of upregulation of proteasomal proteolysis machinery in both cholinergic-deficient and gar-3 mAChR mutants, suggesting that muscarinic activation is critical for stress-responsive upregulation of protein degradation pathways. Further, we find that GAR-3 overexpression in cholinergic motor neurons prolongs survival during prolonged oxidative stress. Our studies demonstrate neuronal modulation of antioxidant defenses through cholinergic activation of G protein-coupled receptor signaling pathways, defining new potential links between cholinergic signaling, oxidative damage, and neurodegenerative disease.
    DOI:  https://doi.org/10.1101/2025.01.06.628021
  21. Mol Biol Cell. 2025 Jan 22. mbcE24120565
    Insights into the role of phosphorylation on microtubule crosslinking by PRC1.
    Ellinor Tai, Austin Henglein, Angus Alfieri, Gauri Saxena, Scott Forth.
      The mitotic spindle is composed of distinct networks of microtubules, including interpolar bundles that can bridge sister kinetochore fibers and bundles that organize the spindle midzone in anaphase. The crosslinking protein PRC1 can mediate such bundling interactions between antiparallel microtubules. PRC1 is a substrate of mitotic kinases including CDK/cyclin-B, suggesting that it can be phosphorylated in metaphase and dephosphorylated in anaphase. How these biochemical changes to specific residues regulate its function and ability to organize bundles has been unclear. Here, we perform biophysical analyses on microtubule networks crosslinked by two PRC1 constructs, one a wild-type reflecting a dephosphorylated state, and one phosphomimetic construct with two threonine to glutamic acid substitutions near PRC1's microtubule binding domain. We find that the wild-type construct builds longer and larger bundles that form more rapidly and are much more resistant to mechanical disruption than the phosphomimetic PRC1. Interestingly, microtubule pairs organized by both constructs behave similarly within the same assays. Our results suggest that phosphorylation of PRC1 in metaphase could tune the protein to stabilize smaller and more flexible bundles, while removal of these PTMs in anaphase would promote the assembly of larger, more mechanically robust bundles to resist chromosome and pole separation forces at the spindle midzone.
    DOI:  https://doi.org/10.1091/mbc.E24-12-0565
  22. Cell Rep. 2025 Jan 23. pii: S2211-1247(25)00009-9. [Epub ahead of print]44(2): 115238
    Aurora B controls microtubule stability to regulate abscission dynamics in stem cells.
    Snježana Kodba, Amber Öztop, Eri van Berkum, Eugene A Katrukha, Malina K Iwanski, Wilco Nijenhuis, Lukas C Kapitein, Agathe Chaigne.
      Abscission is the last step of cell division. It separates the two sister cells and consists of cutting the cytoplasmic bridge. Abscission is mediated by the ESCRT membrane remodeling machinery, which also triggers the severing of a thick bundle of microtubules. Here, we show that rather than being passive actors in abscission, microtubules control abscission speed. Using mouse embryonic stem cells, which transition from slow to fast abscission during exit from naive pluripotency, we investigate the molecular mechanism for the regulation of abscission dynamics and identify crosstalk between Aurora B activity and microtubule stability. We demonstrate that naive stem cells maintain high Aurora B activity on the bridge after cytokinesis. This high Aurora B activity leads to transient microtubule stabilization that delays abscission by decreasing MCAK recruitment to the midbody. In turn, stable microtubules promote the activity of Aurora B. Overall, our data demonstrate that Aurora B-dependent microtubule stability controls abscission dynamics.
    Keywords:  Aurora B; CP: Cell biology; CP: Stem cell research; MCAK; abscission; cytoplasmic bridges; microtubules; stem cells
    DOI:  https://doi.org/10.1016/j.celrep.2025.115238
  23. Bone Marrow Transplant. 2025 Jan 21.
    Myeloablative conditioning in cord blood transplantation for acute myeloid leukemia patients is efficacious only until age 55.
    Shinichiro Oshima, Yasuyuki Arai, Tadakazu Kondo, Shingo Yano, Shigeki Hirabayashi, Naoyuki Uchida, Makoto Onizuka, Shigesaburo Miyakoshi, Masatsugu Tanaka, Satoshi Takahashi, Masayuki Hayashi, Toshiro Kawakita, Yasufumi Uehara, Shuichi Ota, Toru Izumi, Masashi Sawa, Tetsuya Nishida, Yuta Katayama, Koji Nagafuji, Koji Kato, Tatsuo Ichinohe, Yoshiko Atsuta, Masamitsu Yanada.
      Umbilical cord blood transplantation (CBT) is accepted as an effective treatment for acute myeloid leukemia (AML), and reduced-intensity conditioning (RIC), rather than myeloablative conditioning (MAC) regimens allowed elderly patients to be treated safely. However, appropriate intensities of conditioning regimens are still unclear, especially for middle-aged patients. To compare outcomes after RIC and MAC regimens, we analyzed AML patients aged 16 years or older in the Japanese registry database, who underwent single cord unit CBT between 2010-2019. Median ages of the RIC group (n = 1353) and the MAC group (n = 2101) were 59 and 51 years (P < 0.001), respectively. 5-year overall survival (OS) after MAC was superior to that of RIC (38.3% vs 27.7%, P < 0.001) with lower incidence of relapse (33.9% vs 37.4%, P = 0.029) and better neutrophil engraftment (84.7% vs 75.9%, P < 0.001). Detailed subgroup analysis revealed that age at transplantation is the most important factor affecting 5-year OS in RIC and MAC. This analysis identified a threshold of 55 years, beyond which the superiority of MAC disappeared, irrespective of other factors such as disease status or performance status. In conclusion, RIC may be preferable for patients aged 56 or older in CBT for AML due to higher potential toxicities.
    DOI:  https://doi.org/10.1038/s41409-025-02508-2
  24. Am J Hematol. 2025 Jan 22.
    CM313 Monotherapy in Patients With Relapsed/Refractory Multiple Myeloma or Marginal Zone Lymphoma: A Multicenter, Phase 1 Dose-Escalation and Dose-Expansion Trial.
    Huixing Zhou, Zhongxia Huang, Baijun Fang, Hongmei Jing, Zhongjun Xia, Yuqin Song, Zhen Cai, Gang An, Ling Qin, Li Bao, Xin Li, Yuzhang Liu, Yanrong Wang, Ling Li, Wenming Chen.
      
    DOI:  https://doi.org/10.1002/ajh.27573
  25. Cytoskeleton (Hoboken). 2025 Jan 21.
    In Situ Mechanics of the Cytoskeleton.
    Ryota Orii, Hirokazu Tanimoto.
      Not only for man-made architecture but also for living cells, the relationship between force and structure is a fundamental properties that governs their mechanical behaviors. However, our knowledge of the mechanical properties of intracellular structures is very limited because of the lack of direct measurement methods. We established high-force intracellular magnetic tweezers that can generate calibrated forces up to 10 nN, enabling direct force measurements of the cytoskeleton. Using this method, we show that the strain field of the microtubule and actin meshwork follow the same scaling, suggesting that the two cytoskeletal systems behave as an integrated elastic body. Furthermore, quantification of structural response of single microtubules demonstrates that microtubules are enclosed by the elastic medium of filamentous actin. Our results defining the force-structure relationship of the cytoskeleton serve as a framework to understand cellular behaviors by direct intracellular mechanical measurement.
    Keywords:  actin; intracellular magnetic tweezers; microtubule
    DOI:  https://doi.org/10.1002/cm.21995
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