bims-scepro Biomed News
on Stem cell proteostasis
Issue of 2024‒11‒10
sixteen papers selected by
William Grey, University of York



  1. Bioessays. 2024 Nov 06. e2400154
      Hematopoiesis unfolds within the bone marrow niche where hematopoietic stem cells (HSCs) play a central role in continually replenishing blood cells. The hypoxic bone marrow environment imparts peculiar metabolic characteristics to hematopoietic processes. Here, we discuss the internal metabolism of HSCs and describe external influences exerted on HSC metabolism by the bone marrow niche environment. Importantly, we suggest that the metabolic environment and metabolic cues are intertwined with HSC cell fate, and are crucial for hematopoietic processes. Metabolic dysregulation within the bone marrow niche during acute stress, inflammation, and chronic inflammatory conditions can lead to reduced HSC vitality. Additionally, we raise questions regarding metabolic stresses imposed on HSCs during implementation of stem cell protocols such as allo-SCT and gene therapy, and the potential ramifications. Enhancing our comprehension of metabolic influences on HSCs will expand our understanding of pathophysiology in the bone marrow and improve the application of stem cell therapies.
    Keywords:  hematopoiesis; metabolism; stem cells
    DOI:  https://doi.org/10.1002/bies.202400154
  2. Cell Rep. 2024 Oct 25. pii: S2211-1247(24)01130-6. [Epub ahead of print]43(11): 114779
      Bone marrow endothelial cells (BM-ECs) are the essential components of the BM niche and support the function of hematopoietic stem cells (HSCs). However, conditioning for HSC transplantation causes damage to the recipients' BM-ECs and may lead to transplantation-related morbidity. Here, we investigated the cellular and clonal mechanisms of BM-EC regeneration after irradiative conditioning. Using single-cell RNA sequencing, imaging, and flow cytometry, we revealed how the heterogeneous pool of BM-ECs changes during regeneration from irradiation stress. Next, we developed a single-cell in vitro clonogenic assay and demonstrated that all EC fractions hold a high potential to reenter the cell cycle and form vessel-like structures. Finally, we used Rainbow mice and a machine-learning-based model to show that the regeneration of BM-ECs after irradiation is mostly polyclonal and driven by the broad fraction of BM-ECs; however, the cell output among clones varies at later stages of regeneration.
    Keywords:  CP: Stem cell research; bone marrow endothelial cells; bone marrow niche; bone marrow regeneration; conditioning; hematopoietic stem cells; irradiation; sinusoids; transplantation
    DOI:  https://doi.org/10.1016/j.celrep.2024.114779
  3. Cancer Res. 2024 Nov 04.
      Internal tandem duplication (ITD) in the FMS-like receptor tyrosine kinase-3 (FLT3) is one of the most frequent mutations in acute myeloid leukemia (AML) and is associated with poor prognosis. FLT3-ITD mutations result in endoplasmic reticulum (ER) retention and constitutive autophosphorylation of FLT3. The PR/SET domain 16 (PRDM16) is highly expressed in FLT3-ITD+ AML patients, suggesting it might play a role in leukemogenesis. Here, we revealed that genetic and pharmacological suppression of PRDM16 greatly slowed the progression of FLT3-ITD-driven leukemia, sensitized leukemic cells to tyrosine kinase inhibitors (TKIs), and extended the survival of leukemic mice. PRDM16 enhanced activation of oncogenic FLT3-ITD and ligand-dependent activation of wild-type FLT3 in leukemic cells. Mechanistically, PRDM16 mediated monomethylation of FLT3-ITD at lysine 614 and promoted its ER localization, resulting in enhanced FLT3 signaling in leukemia cells. Moreover, pharmacological suppression of FLT3-ITD methylation in combination with TKIs increased the elimination of FLT3-ITD+ AML cells. Altogether, these results suggest that PRDM16 boosts oncogenic FLT3 signaling in leukemic cells by prompting FLT3-ITD methylation. Therefore, PRDM16 may serve as a therapeutic target for AML.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-24-0577
  4. Elife. 2024 Nov 06. pii: RP92074. [Epub ahead of print]12
      The advent of tyrosine kinase inhibitors (TKIs) as treatment of chronic myeloid leukemia (CML) is a paradigm in molecularly targeted cancer therapy. Nonetheless, TKI-insensitive leukemia stem cells (LSCs) persist in most patients even after years of treatment and are imperative for disease progression as well as recurrence during treatment-free remission (TFR). Here, we have generated high-resolution single-cell multiomics maps from CML patients at diagnosis, retrospectively stratified by BCR::ABL1IS (%) following 12 months of TKI therapy. Simultaneous measurement of global gene expression profiles together with >40 surface markers from the same cells revealed that each patient harbored a unique composition of stem and progenitor cells at diagnosis. The patients with treatment failure after 12 months of therapy had a markedly higher abundance of molecularly defined primitive cells at diagnosis compared to the optimal responders. The multiomic feature landscape enabled visualization of the primitive fraction as a mixture of molecularly distinct BCR::ABL1+ LSCs and BCR::ABL1-hematopoietic stem cells (HSCs) in variable ratio across patients, and guided their prospective isolation by a combination of CD26 and CD35 cell surface markers. We for the first time show that BCR::ABL1+ LSCs and BCR::ABL1- HSCs can be distinctly separated as CD26+CD35- and CD26-CD35+, respectively. In addition, we found the ratio of LSC/HSC to be higher in patients with prospective treatment failure compared to optimal responders, at diagnosis as well as following 3 months of TKI therapy. Collectively, this data builds a framework for understanding therapy response and adapting treatment by devising strategies to extinguish or suppress TKI-insensitive LSCs.
    Keywords:  BCR-ABL1; CD26; CD35; CITE-Seq; CML; cancer biology; genetics; genomics; human; leukemic stem cell
    DOI:  https://doi.org/10.7554/eLife.92074
  5. Methods Enzymol. 2024 ;pii: S0076-6879(24)00404-X. [Epub ahead of print]707 101-152
      The multiple functions of mitochondria are governed by their proteome comprising 1000-1500 proteins depending on the organism. However, only few proteins are synthesized inside mitochondria, whereas most are "born" outside mitochondria. To reach their destined location, these mitochondrial proteins follow specific import routes established by a mitochondrial translocase network. A detailed understanding of the role and interplay of the different translocases is imperative to understand mitochondrial biology and how mitochondria are integrated into the cellular network. Mass spectrometry (MS) proved to be effective to study the translocase network regarding composition, functions, interplay, and cellular responses evoked by dysfunction. In this chapter, we provide protocols tailored to MS-enabled functional analysis of mutants and interactomes of mitochondrial translocation proteins. In the first part, we exemplify the MS-based proteomics analysis of translocation mutants for delineating the human mitochondrial importome following depletion of the central translocation protein TOMM40. The protocol comprises metabolic stable isotope labeling, TOMM40 knockdown, preparation of mitochondrial fractions, and sample preparation for liquid chromatography (LC)-MS. For deep MS analysis, prefractionation of peptide mixtures by high pH reversed-phase LC is described. In the second part, we outline an affinity purification MS approach to reveal the association of an orphaned protein with the translocase TIM23. The protocol covers FLAG-tag affinity purification of protein complexes from mitochondrial fractions and downstream sample preparation for interactome analysis. In the last unifying part, we describe methods for LC-MS, data processing, statistical analysis and visualization of quantitative MS data, and provide a Python code for effective, customizable analysis.
    Keywords:  Affinity-purification mass spectrometry; Data analysis; Importome; Interactome; Mass spectrometry; Mitochondria; Protein quantification; Proteomics; SILAC; Translocation mutants
    DOI:  https://doi.org/10.1016/bs.mie.2024.07.059
  6. Leuk Res. 2024 Oct 26. pii: S0145-2126(24)00165-6. [Epub ahead of print]147 107599
      Multiple myeloma is an aggressive neoplasm of plasma cells. While numerous drugs have gained approval, the absence of established predictive markers for individual drug responses poses a challenge. In this study, we explored the microwell- and fluorescence-based Cellply CC-Array® technology for high-throughput analysis of in vitro drug responses as a potential predictive marker for patient treatment outcomes. Furthermore, we investigated its application for evaluating effector cell effectiveness. Mononuclear cells were isolated from the bone marrow of 22 patients, and in vitro drug response of primary myeloma cells was analyzed. In vitro responses towards melphalan, bortezomib, and dexamethasone in primary patient samples correlated with clinical response of the patients. The approach exhibited limitations in identifying sensitivity towards lenalidomide, daratumumab, and elotuzumab due to limited culturing time caused by poor myeloma viability in vitro. Through the analysis of cell proximity, the platform enabled the assessment of individual anti-tumor activity from NK and T cells. In summary, the CC-Array microwell technology allowed assessment of myeloma cell responses to selected drugs used in multiple myeloma therapy in vitro. To further validate these in vitro results against in vivo outcomes, screening a larger cohort is necessary.
    Keywords:  Drug testing; Multiple myeloma; Personalized therapy; Resistance; Response prediction
    DOI:  https://doi.org/10.1016/j.leukres.2024.107599
  7. Exp Hematol. 2024 Nov 02. pii: S0301-472X(24)00534-4. [Epub ahead of print] 104669
      Induced pluripotent stem cells (iPSCs) have emerged as powerful tools for in vitro modeling of bone marrow failure (BMF) syndromes and hereditary conditions predisposing to myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). This review synthesizes recent advances in iPSC-based disease modeling for various inherited BMF/MDS disorders, including Fanconi anemia, dyskeratosis congenita, Diamond Blackfan anemia syndrome, Shwachman-Diamond syndrome, severe congenital neutropenia, and GATA2, RUNX1, ETV6, ANKRD26, SAMD9, SAMD9L and ADH5/ALDH2 syndromes. While the majority of these iPSC lines are derived from patient cells, some are generated by introducing patient-specific mutations into healthy iPSC backgrounds, offering complementary approaches to disease modeling. The review highlights the ability of iPSCs to recapitulate key disease phenotypes, such as impaired hematopoietic differentiation, telomere dysfunction, and defects in DNA repair or ribosome biogenesis. We discuss how these models have enhanced our understanding of disease pathomechanisms, hematopoietic defects, and potential therapeutic approaches. Challenges in generating and maintaining disease-specific iPSCs are examined, particularly for disorders involving DNA repair. We emphasize the necessity of creating isogenic controls to elucidate genotype-phenotype relationships. Furthermore, we address limitations of current iPSC models, including genetic variability among iPSC clones derived from the same patient, and difficulties in achieving robust engraftment of iPSC-derived hematopoietic progenitor cells in mouse transplantation models. The review also explores future directions, including the potential of iPSC models for drug discovery and personalized medicine approaches. This review underscores the significance of iPSC technology in advancing our understanding of inherited hematopoietic disorders and its potential to inform novel therapeutic strategies.
    DOI:  https://doi.org/10.1016/j.exphem.2024.104669
  8. Cell. 2024 Oct 30. pii: S0092-8674(24)01197-8. [Epub ahead of print]
      Targeted protein degradation (TPD) utilizes molecular glues or proteolysis-targeting chimeras (PROTACs) to eliminate disease-causing proteins by promoting their interaction with E3 ubiquitin ligases. Current TPD approaches are limited by reliance on a small number of constitutively active E3 ubiquitin ligases. Here, we report that (S)-ACE-OH, a metabolite of the antipsychotic drug acepromazine, acts as a molecular glue to induce an interaction between the E3 ubiquitin ligase TRIM21 and the nucleoporin NUP98, leading to the degradation of nuclear pore proteins and disruption of nucleocytoplasmic trafficking. Functionalization of acepromazine into PROTACs enabled selective degradation of multimeric proteins, such as those within biomolecular condensates, while sparing monomeric proteins. This selectivity is consistent with the requirement of substrate-induced clustering for TRIM21 activation. As aberrant protein assemblies cause diseases such as autoimmunity, neurodegeneration, and cancer, our findings highlight the potential of TRIM21-based multimer-selective degraders as a strategy to tackle the direct causes of these diseases.
    Keywords:  E3 ubiquitin ligase; PROTAC; TRIM21; biomolecular condensate; molecular glue; multimeric proteins; nuclear pore complex; targeted protein degradation
    DOI:  https://doi.org/10.1016/j.cell.2024.10.015
  9. Haematologica. 2024 Nov 07.
      Since 2017, targeted therapies combined with conventional intensive chemotherapy have started to improve outcome of patients with acute myeloid leukemia (AML). However, even before these innovations outcomes with intensive chemotherapy have improved, which has not yet been extensively studied. Thus, we used a large pan-European multicenter dataset of the HARMONY Alliance to evaluate treatment-time dependent outcomes over two decades. In 5359 AML patients, we compared the impact of intensive induction therapy on outcome over four consecutive 5-year calendar periods from 1997 to 2016. During that time, the 5- year survival of AML patients improved significantly, also across different genetic risk groups. In particular, the 60-day mortality rate has dropped from 13.0% to 4.7% over time. The independent effect of calendar periods on outcome was confirmed in multivariate models. Improvements were documented both for patients.
    DOI:  https://doi.org/10.3324/haematol.2024.285805
  10. Oncogene. 2024 Nov 01.
      Sex influences many biological outcomes, but how sex affects hematopoietic stem cell (HSC) aging and hematological disorders is poorly understood. The widespread use of young animal models to study age-related diseases further complicates these matters. Using aged and long-lived BALB/c mouse models, we discovered that aging mice exhibit sex-dependent disparities, mirroring aging humans, in developing myeloid skewing, anemia, and leukemia. These disparities are underlined by sex-differentiated HSC aging characteristics across the population, single-cell, and molecular levels. The HSC population expanded significantly with aging and longevity in males, but this occurred to a much lesser degree in aging females that instead expanded committed progenitors. Aging male HSCs are more susceptible to BCR-ABL1 transformation with faster development of chronic myeloid leukemia (CML) than female HSCs. Additionally, the loss of the aging regulator Sirt1 inhibited CML development in aging male but not female mice. Our results showed for the first time that sex-differentiated HSC aging impacts hematopoiesis, leukemogenesis, and certain gene functions. This discovery provides insights into understanding age-dependent hematological diseases and sex-targeted strategies for the treatment and prevention of certain blood disorders and cancer.
    DOI:  https://doi.org/10.1038/s41388-024-03197-9
  11. Nat Rev Mol Cell Biol. 2024 Nov 05.
      Cells rely on the endoplasmic reticulum (ER) to fold and assemble newly synthesized transmembrane and secretory proteins - essential for cellular structure-function and for both intracellular and intercellular communication. To ensure the operative fidelity of the ER, eukaryotic cells leverage the unfolded protein response (UPR) - a stress-sensing and signalling network that maintains homeostasis by rebalancing the biosynthetic capacity of the ER according to need. The metazoan UPR can also redirect signalling from cytoprotective adaptation to programmed cell death if homeostasis restoration fails. As such, the UPR benefits multicellular organisms by preserving optimally functioning cells while removing damaged ones. Nevertheless, dysregulation of the UPR can be harmful. In this Review, we discuss the UPR and its regulatory processes as a paradigm in health and disease. We highlight important recent advances in molecular and mechanistic understanding of the UPR that enable greater precision in designing and developing innovative strategies to harness its potential for therapeutic gain. We underscore the rheostatic character of the UPR, its contextual nature and critical open questions for its further elucidation.
    DOI:  https://doi.org/10.1038/s41580-024-00794-0
  12. Methods Enzymol. 2024 ;pii: S0076-6879(24)00381-1. [Epub ahead of print]707 153-171
      Precise protein localization is essential for normal cellular functions. However, recent studies have revealed that protein targeting is error-prone, and tail-anchored proteins mistargeted to mitochondria are transferred to the endoplasmic reticulum (ER) by an ATPase Msp1 (yeast)/ATAD1 (human) in the mitochondrial outer membrane for further quality examination in the ER to determine their fate, degradation or re-targeting. Analysis of the inter-organelle transfer of proteins requires a combination of time-lapse fluorescence microscopy and a system to achieve regulation of the protein levels of both transfer substrates and factors regulating the transfer in a coordinated manner at precise timing. This can be achieved by using a promoter switch for expression and acute depletion of involved factors through the degron-based proteasome system. In this chapter, we will describe methods to analyze inter-organelle protein transfer by fluorescence microscope within living yeast cells, by using the example of Msp1-mediated transfer of mistargeted proteins from mitochondria to the ER.
    Keywords:  AID degradation system; Endoplasmic reticulum; Fluorescence microscope; GET system; Inter-organelle protein transfer; Mitochondria; Msp1; Tail-anchored protein
    DOI:  https://doi.org/10.1016/bs.mie.2024.07.041
  13. FASEB J. 2024 Nov 15. 38(21): e70147
      Mechanistic target of rapamycin complex 1 (mTORC1) is a master regulator of cell growth and its dysregulation leads to a variety of human diseases. Although NPRL2, an essential component of the GATOR1 complex, is reported to effectively suppress amino acid-induced mTORC1 activation, the regulation of NPRL2 protein stability is unclear. In this study, we show that chaperon-associated ubiquitin ligase CHIP interacts with NPRL2 and promotes its polyubiquitination and proteasomal degradation. Moreover, HSP70 mediates CHIP-induced ubiquitination and degradation of NPRL2. Consistently, overexpression of HSP70 enhances whereas HSP70 depletion inhibits amino acid-induced mTORC1 activation. Accordingly, knockdown of HSP70 promotes basal autophagic flux, and inhibits cell growth and proliferation. Taken together, these results demonstrated that HSP70 is a novel activator of mTORC1 through mediating CHIP-induced ubiquitination and degradation of NPRL2.
    Keywords:  CHIP; HSP70; NPRL2; amino acid; mTORC1; ubiquitination
    DOI:  https://doi.org/10.1096/fj.202401352R
  14. Commun Biol. 2024 Nov 03. 7(1): 1429
      Victims of explosive events frequently suffer from blast lung injuries. Immune system has been implicated in the pathogenesis of this disease. However, systemic immune responses underlying the progression and recovery of injury repair remain poorly understood. Here, we depict the systemic landscape of immune dysregulation during blast lung injury and uncover immune recovery patterns. Single-cell analyses reveal dramatic changes in neutrophils, macrophages, monocytes, dendritic cells, and eosinophils after a gas explosion, along with early involvement of CD4 T, CD8 T, and Th17 cells. We demonstrate that myeloid cells primarily exert functions during the acute phase, while the spleen serves as an alternative source of granulocytes. Granulopoiesis is initiated in the bone marrow at a later stage during blast lung injury recovery, rather than at the acute stage. These findings contribute to a better understanding of the pathogenesis and provide valuable insights for potential immune interventions in blast lung injury.
    DOI:  https://doi.org/10.1038/s42003-024-07151-z
  15. Nat Mater. 2024 Nov 01.
      Cells can deform their local niche in three dimensions via whole-cell movements such as spreading, migration or volume expansion. These behaviours, occurring over hours to days, influence long-term cell fates including differentiation. Here we report a whole-cell movement that occurs in sliding hydrogels at the minutes timescale, termed cell tumbling, characterized by three-dimensional cell dynamics and hydrogel deformation elicited by heightened seconds-to-minutes-scale cytoskeletal and nuclear activity. Studies inhibiting or promoting the cell tumbling of mesenchymal stem cells show that this behaviour enhances differentiation into chondrocytes. Further, it is associated with a decrease in global chromatin accessibility, which is required for enhanced differentiation. Cell tumbling also occurs during differentiation into other lineages and its differentiation-enhancing effects are validated in various hydrogel platforms. Our results establish that cell tumbling is an additional regulator of stem cell differentiation, mediated by rapid niche deformation and nuclear mechanotransduction.
    DOI:  https://doi.org/10.1038/s41563-024-02038-0
  16. Biochim Biophys Acta Mol Cell Res. 2024 Oct 26. pii: S0167-4889(24)00212-X. [Epub ahead of print] 119869
      The endoplasmic reticulum (ER) is a dynamic organelle that is a site of the synthesis of proteins and lipids and contributes to the regulation of proteostasis, lipid metabolism, redox balance, and calcium storage/-dependent signaling events. The disruption of ER homeostasis due to the accumulation of misfolded proteins in the ER causes ER stress which activates the unfolded protein response (UPR) system through the activation of IRE1, PERK, and ATF6. Activation of UPR is observed in various cancers and the tumor cells effectively utilize the UPR system to overcome ER stress. Also, ER stress and autophagy are the stress response mechanisms that operate together to maintain cellular homeostasis. In cancers, ER stress-mediated autophagy can function as either pro-survival or pro-death in a context-dependent manner. ER stress-mediated autophagy can have crosstalk with other types of cell death pathways including apoptosis and ferroptosis. In this article, we have reviewed the role of ER stress in the regulation of autophagy-mediated tumorigenesis and its interactions with other cell death mechanisms such as apoptosis and ferroptosis. We have also comprehensively discussed the effect of ER stress-mediated autophagy on cancer progression and chemotherapeutic resistance.
    Keywords:  Autophagy; Cancer; Cell death; Endoplasmic reticulum stress; Ferroptosis
    DOI:  https://doi.org/10.1016/j.bbamcr.2024.119869