bims-scepro Biomed News
on Stem cell proteostasis
Issue of 2024–03–10
twenty-two papers selected by
William Grey, University of York
  1. Inhibition of mitochondrial folate metabolism drives differentiation through mTORC1 mediated purine sensing.
  2. The essence of quiescence.
  3. Ex vivo expansion potential of murine hematopoietic stem cells is a rare property only partially predicted by phenotype.
  4. The dark side of stemness - the role of hematopoietic stem cells in development of blood malignancies.
  5. Extramedullary hematopoiesis in cancer.
  6. Integrative single-cell expression and functional studies unravels a sensitization to cytarabine-based chemotherapy through HIF pathway inhibition in AML leukemia stem cells.
  7. Osteomacs promote maintenance of murine hematopoiesis through megakaryocyte-induced upregulation of Embigin and CD166.
  8. A mitochondrial NADPH-cholesterol axis regulates extracellular vesicle biogenesis to support hematopoietic stem cell fate.
  9. Engraftment of adult hematopoietic stem and progenitor cells in a novel model of humanized mice.
  10. Ex vivo expansion of hematopoietic stem cells in two/ three-dimensional co-cultures with various source of stromal cells.
  11. Bahcc1 is critical for the aberrant epigenetic program in a mouse model of MLL-ENL-mediated leukemia.
  12. Hematopoietic stem cell fate under the influence of Ser/Thr protein phosphatases.
  13. Small extracellular vesicles derived from acute myeloid leukemia cells promote leukemogenesis by transferring miR-221-3p.
  14. Immunophenotypic characterization of leukemic stem cells in acute myeloid leukemia using single tube 10-colour panel by multiparametric flow cytometry: Deciphering the spectrum, complexity and immunophenotypic heterogeneity.
  15. Advances in the study of protein folding and endoplasmic reticulum-associated degradation in mammal cells.
  16. Biomaterials-assisted therapeutic cell production and modification in vivo.
  17. Differentiation route determines the functional outputs of adult megakaryopoiesis.
  18. Viscosity-dependent control of protein synthesis and degradation.
  19. Cytokinetic abscission requires actin-dependent microtubule severing.
  20. Mapping the substrate landscape of protein phosphatase 2A catalytic subunit PPP2CA.
  21. Identification of molecular signatures defines the differential proteostasis response in induced spinal and cranial motor neurons.
  22. Kinase signalling adaptation supports dysfunctional mitochondria in disease.
  1. Nat Commun. 2024 Mar 02. 15(1): 1931
    Inhibition of mitochondrial folate metabolism drives differentiation through mTORC1 mediated purine sensing.
    Martha M Zarou, Kevin M Rattigan, Daniele Sarnello, Engy Shokry, Amy Dawson, Angela Ianniciello, Karen Dunn, Mhairi Copland, David Sumpton, Alexei Vazquez, G Vignir Helgason.
      Supporting cell proliferation through nucleotide biosynthesis is an essential requirement for cancer cells. Hence, inhibition of folate-mediated one carbon (1C) metabolism, which is required for nucleotide synthesis, has been successfully exploited in anti-cancer therapy. Here, we reveal that mitochondrial folate metabolism is upregulated in patient-derived leukaemic stem cells (LSCs). We demonstrate that inhibition of mitochondrial 1C metabolism through impairment of de novo purine synthesis has a cytostatic effect on chronic myeloid leukaemia (CML) cells. Consequently, changes in purine nucleotide levels lead to activation of AMPK signalling and suppression of mTORC1 activity. Notably, suppression of mitochondrial 1C metabolism increases expression of erythroid differentiation markers. Moreover, we find that increased differentiation occurs independently of AMPK signalling and can be reversed through reconstitution of purine levels and reactivation of mTORC1. Of clinical relevance, we identify that combination of 1C metabolism inhibition with imatinib, a frontline treatment for CML patients, decreases the number of therapy-resistant CML LSCs in a patient-derived xenograft model. Our results highlight a role for folate metabolism and purine sensing in stem cell fate decisions and leukaemogenesis.
    DOI:  https://doi.org/10.1038/s41467-024-46114-0
  2. Stem Cells Dev. 2024 Mar 06.
    The essence of quiescence.
    Peter J Quesenberry, Mark S Dooner, Mandy Pereira, Nathalie Oulhen, Sicheng Wen.
      Historically hematopoietic stem cells are believed to be predominantly dormant but could be induced into active cell cycle under specific conditions. This review, coupled with years of research from our laboratory, challenges this belief by demonstrating a significant portion of hematopoietic stem cells are actively cycling rather than quiescent. This addresses a major heuristic error in the understanding of hematopoietic stem cells which has shaped this field for decades. By evaluating the cycle status of engraftable hematopoietic stem cells in whole unseparated bone marrow, we demonstrated that a significant portion of these cells are actively cycling, and further confirmed by tritiated thymidine suicide and BrdU labeling assays. Moreover, by analyzing both whole unseparated bone marrow and purified lineage-negative hematopoietic stem cells in murine models, our findings indicate that lineage-positive cells, usually discarded during purification, actually contain actively cycling stem cells. Taken together, our findings highlight that hematopoietic stem cells with the characterizations of actively cycling and expressing differentiation epitopes correct a misunderstanding in stem cell biology. Furthermore, these findings provide valuable insights for a better understanding of the actively cycling hematopoietic stem cells in the field of stem cell biology.
    DOI:  https://doi.org/10.1089/scd.2024.0032
  3. Elife. 2024 Mar 06. pii: RP91826. [Epub ahead of print]12
    Ex vivo expansion potential of murine hematopoietic stem cells is a rare property only partially predicted by phenotype.
    Qinyu Zhang, Rasmus Olofzon, Anna Konturek-Ciesla, Ouyang Yuan, David Bryder.
      The scarcity of hematopoietic stem cells (HSCs) restricts their use in both clinical settings and experimental research. Here, we examined a recently developed method for expanding rigorously purified murine HSCs ex vivo. After 3 weeks of culture, only 0.1% of cells exhibited the input HSC phenotype, but these accounted for almost all functional long-term HSC activity. Input HSCs displayed varying potential for ex vivo self-renewal, with alternative outcomes revealed by single-cell multimodal RNA and ATAC sequencing profiling. While most HSC progeny offered only transient in vivo reconstitution, these cells efficiently rescued mice from lethal myeloablation. The amplification of functional HSC activity allowed for long-term multilineage engraftment in unconditioned hosts that associated with a return of HSCs to quiescence. Thereby, our findings identify several key considerations for ex vivo HSC expansion, with major implications also for assessment of normal HSC activity.
    Keywords:  ex vivo expansion; hematopoietic stem cell; mouse; regenerative medicine; stem cells; transplantation
    DOI:  https://doi.org/10.7554/eLife.91826
  4. Front Oncol. 2024 ;14 1308709
    The dark side of stemness - the role of hematopoietic stem cells in development of blood malignancies.
    Jadwiga Filipek-Gorzała, Patrycja Kwiecińska, Agata Szade, Krzysztof Szade.
      Hematopoietic stem cells (HSCs) produce all blood cells throughout the life of the organism. However, the high self-renewal and longevity of HSCs predispose them to accumulate mutations. The acquired mutations drive preleukemic clonal hematopoiesis, which is frequent among elderly people. The preleukemic state, although often asymptomatic, increases the risk of blood cancers. Nevertheless, the direct role of preleukemic HSCs is well-evidenced in adult myeloid leukemia (AML), while their contribution to other hematopoietic malignancies remains less understood. Here, we review the evidence supporting the role of preleukemic HSCs in different types of blood cancers, as well as present the alternative models of malignant evolution. Finally, we discuss the clinical importance of preleukemic HSCs in choosing the therapeutic strategies and provide the perspective on further studies on biology of preleukemic HSCs.
    Keywords:  acute lymphoblastic leukemia; acute myeloid leukemia; chronic lymphocytic leukemia; chronic myeloid leukemia; clonal hematopoiesis; hematopoietic stem cell; mature cell neoplasm; preleukemic state
    DOI:  https://doi.org/10.3389/fonc.2024.1308709
  5. Exp Mol Med. 2024 Mar 05.
    Extramedullary hematopoiesis in cancer.
    Derek A G Barisas, Kyunghee Choi.
      Hematopoiesis can occur outside of the bone marrow during inflammatory stress to increase the production of primarily myeloid cells at extramedullary sites; this process is known as extramedullary hematopoiesis (EMH). As observed in a broad range of hematologic and nonhematologic diseases, EMH is now recognized for its important contributions to solid tumor pathology and prognosis. To initiate EMH, hematopoietic stem cells (HSCs) are mobilized from the bone marrow into the circulation and to extramedullary sites such as the spleen and liver. At these sites, HSCs primarily produce a pathological subset of myeloid cells that contributes to tumor pathology. The EMH HSC niche, which is distinct from the bone marrow HSC niche, is beginning to be characterized. The important cytokines that likely contribute to initiating and maintaining the EMH niche are KIT ligands, CXCL12, G-CSF, IL-1 family members, LIF, TNFα, and CXCR2. Further study of the role of EMH may offer valuable insights into emergency hematopoiesis and therapeutic approaches against cancer. Exciting future directions for the study of EMH include identifying common and distinct EMH mechanisms in cancer, infectious diseases, and chronic autoimmune diseases to control these conditions.
    DOI:  https://doi.org/10.1038/s12276-024-01192-4
  6. Hemasphere. 2024 Feb;8(2): e45
    Integrative single-cell expression and functional studies unravels a sensitization to cytarabine-based chemotherapy through HIF pathway inhibition in AML leukemia stem cells.
    Talia Velasco-Hernandez, Juan L Trincado, Meritxell Vinyoles, Adria Closa, Alba Martínez-Moreno, Francisco Gutiérrez-Agüera, Oscar Molina, Virginia C Rodríguez-Cortez, Pau Ximeno-Parpal, Narcís Fernández-Fuentes, Paolo Petazzi, Sergi Beneyto-Calabuig, Lars Velten, Paola Romecin, Raquel Casquero, Fernando Abollo-Jiménez, Rafael D de la Guardia, Patricia Lorden, Alex Bataller, Hélène Lapillonne, Ronald W Stam, Susana Vives, Montserrat Torrebadell, Jose L Fuster, Clara Bueno, Jean-Emmanuel Sarry, Eduardo Eyras, Holger Heyn, Pablo Menéndez.
      Relapse remains a major challenge in the clinical management of acute myeloid leukemia (AML) and is driven by rare therapy-resistant leukemia stem cells (LSCs) that reside in specific bone marrow niches. Hypoxia signaling maintains cells in a quiescent and metabolically relaxed state, desensitizing them to chemotherapy. This suggests the hypothesis that hypoxia contributes to the chemoresistance of AML-LSCs and may represent a therapeutic target to sensitize AML-LSCs to chemotherapy. Here, we identify HIFhigh and HIFlow specific AML subgroups (inv(16)/t(8;21) and MLLr, respectively) and provide a comprehensive single-cell expression atlas of 119,000 AML cells and AML-LSCs in paired diagnostic-relapse samples from these molecular subgroups. The HIF/hypoxia pathway signature is attenuated in AML-LSCs compared with more differentiated AML cells but is more expressed than in healthy hematopoietic cells. Importantly, chemical inhibition of HIF cooperates with standard-of-care chemotherapy to impair AML growth and to substantially eliminate AML-LSCs in vitro and in vivo. These findings support the HIF pathway in the stem cell-driven drug resistance of AML and unravel avenues for combinatorial targeted and chemotherapy-based approaches to specifically eliminate AML-LSCs.
    DOI:  https://doi.org/10.1002/hem3.45
  7. Stem Cell Reports. 2024 Feb 28. pii: S2213-6711(24)00042-0. [Epub ahead of print]
    Osteomacs promote maintenance of murine hematopoiesis through megakaryocyte-induced upregulation of Embigin and CD166.
    Safa F Mohamad, Roy El Koussa, Joydeep Ghosh, Rachel Blosser, Andrea Gunawan, Justin Layer, Chi Zhang, Sonali Karnik, Utpal Davé, Melissa A Kacena, Edward F Srour.
      Maintenance of hematopoietic stem cell (HSC) function in the niche is an orchestrated event. Osteomacs (OM) are key cellular components of the niche. Previously, we documented that osteoblasts, OM, and megakaryocytes interact to promote hematopoiesis. Here, we further characterize OM and identify megakaryocyte-induced mediators that augment the role of OM in the niche. Single-cell mRNA-seq, mass spectrometry, and CyTOF examination of megakaryocyte-stimulated OM suggested that upregulation of CD166 and Embigin on OM augment their hematopoiesis maintenance function. CD166 knockout OM or shRNA-Embigin knockdown OM confirmed that the loss of these molecules significantly reduced the ability of OM to augment the osteoblast-mediated hematopoietic-enhancing activity. Recombinant CD166 and Embigin partially substituted for OM function, characterizing both proteins as critical mediators of OM hematopoietic function. Our data identify Embigin and CD166 as OM-regulated critical components of HSC function in the niche and potential participants in various in vitro manipulations of stem cells.
    Keywords:  CD166; Embigin; hematopoietic stem cell; megakaryocytes; niche; osteoblast; osteomacs
    DOI:  https://doi.org/10.1016/j.stemcr.2024.02.004
  8. Cell Stem Cell. 2024 Mar 07. pii: S1934-5909(24)00047-X. [Epub ahead of print]31(3): 359-377.e10
    A mitochondrial NADPH-cholesterol axis regulates extracellular vesicle biogenesis to support hematopoietic stem cell fate.
    Massimo Bonora, Claudia Morganti, Nick van Gastel, Kyoko Ito, Enrica Calura, Ilaria Zanolla, Letizia Ferroni, Yang Zhang, Yookyung Jung, Gabriele Sales, Paolo Martini, Takahisa Nakamura, Francesco Massimo Lasorsa, Toren Finkel, Charles P Lin, Barbara Zavan, Paolo Pinton, Irene Georgakoudi, Chiara Romualdi, David T Scadden, Keisuke Ito.
      Mitochondrial fatty acid oxidation (FAO) is essential for hematopoietic stem cell (HSC) self-renewal; however, the mechanism by which mitochondrial metabolism controls HSC fate remains unknown. Here, we show that within the hematopoietic lineage, HSCs have the largest mitochondrial NADPH pools, which are required for proper HSC cell fate and homeostasis. Bioinformatic analysis of the HSC transcriptome, biochemical assays, and genetic inactivation of FAO all indicate that FAO-generated NADPH fuels cholesterol synthesis in HSCs. Interference with FAO disturbs the segregation of mitochondrial NADPH toward corresponding daughter cells upon single HSC division. Importantly, we have found that the FAO-NADPH-cholesterol axis drives extracellular vesicle (EV) biogenesis and release in HSCs, while inhibition of EV signaling impairs HSC self-renewal. These data reveal the existence of a mitochondrial NADPH-cholesterol axis for EV biogenesis that is required for hematopoietic homeostasis and highlight the non-stochastic nature of HSC fate determination.
    Keywords:  HSC self-renewal; NADPH; cholesterol; exosomes; extracellular vesicles; fate determination; fatty acid oxidation; hematopoietic stem cell; metabolism; mitochondria
    DOI:  https://doi.org/10.1016/j.stem.2024.02.004
  9. iScience. 2024 Mar 15. 27(3): 109238
    Engraftment of adult hematopoietic stem and progenitor cells in a novel model of humanized mice.
    Chun I Yu, Rick Maser, Florentina Marches, Jacques Banchereau, Karolina Palucka.
      Pre-clinical use of humanized mice transplanted with CD34+ hematopoietic stem and progenitor cells (HSPCs) is limited by insufficient engraftment with adult non-mobilized HSPCs. Here, we developed a novel immunodeficient mice based on NOD-SCID-Il2γc-/- (NSG) mice to support long-term engraftment with human adult HSPCs. As both Flt3L and IL-6 are critical for many aspects of hematopoiesis, we knock-out mouse Flt3 and knock-in human IL6 gene. The resulting mice showed an increase in the availability of mouse Flt3L to human cells and a dose-dependent production of human IL-6 upon activation. Upon transplantation with low number of human HSPCs from adult bone marrow, these humanized mice demonstrated a significantly higher engraftment with multilineage differentiation of human lymphoid and myeloid cells, and tissue colonization at one year after adult HSPC transplant. Thus, these mice enable studies of human hematopoiesis and tissue colonization over time and may facilitate building autologous models for immuno-oncology studies.
    Keywords:  Immunology; Molecular biology; Stem cells research
    DOI:  https://doi.org/10.1016/j.isci.2024.109238
  10. Tissue Cell. 2024 Feb 19. pii: S0040-8166(24)00032-6. [Epub ahead of print]87 102331
    Ex vivo expansion of hematopoietic stem cells in two/ three-dimensional co-cultures with various source of stromal cells.
    Nasim Mayeli Fereydani, Hamid Galehdari, Elham Hoveizi, Arash Alghasi, Monireh Ajami.
      The ex vivo expansion of hematopoietic stem cells, with both high quantities and quality, is considered a paramount issue in cell and gene therapy for hematological diseases. Complex interactions between the bone marrow microenvironment and hematopoietic stem cells reveal the importance of using 2D and 3D coculture as a physiological system simulator in the proliferation, differentiation, and homeostasis of HSCs. Herein, the capacity of mesenchymal stem cells derived from different sources to support the expansion and maintenance of HSPC was compared with each other. We evaluated the fold increase of HSPC, CD34 marker expression, cytokine secretion profile of different MSCs, and the frequency of hematopoietic colony-forming unit parameters. Our results show that there was no significant difference between adipose tissue-MSC, Wharton jelly-MSC, and Endometrial-MSCs in HSPC expansion (fold increase: 34.74±4.38 in Wj-MSC, 32.22±5.07 in AD-MSC, 25.9±1.27 in En-MSCs); However, there were significantly more than the expansion media alone (4.4±0.69). The results obtained from the cytokine secretion analysis also confirm these results. Also, there were significant differences in the clonogenicity of Wj-MSC, En-MSCs, and expansion media (CFU-GEMM: 7±1.73, 2.3±1.15, and 2.3±1.52), which indicated that Wj-MSC could significantly maintain the primitive state. As a result, using Wj-mesenchymal stem cells on a 3D coculture system effectively increases the HSPC expansion and maintains the colonization potential of hematopoietic stem cells.
    Keywords:  Adipose tissue; Endometrial mesenchymal stem cells; Ex vivo expansion; Hematopoietic stem cells; Hydrogel; Wharton jelly
    DOI:  https://doi.org/10.1016/j.tice.2024.102331
  11. Blood Adv. 2024 Mar 07. pii: bloodadvances.2023011320. [Epub ahead of print]
    Bahcc1 is critical for the aberrant epigenetic program in a mouse model of MLL-ENL-mediated leukemia.
    Ryoichi Ono, Akihide Nakamura, Masahiro Masuya, Makoto Shinmei, Isao Tawara, Tetsuya Nosaka.
      In leukemogenesis, genotoxic stress in hematopoietic stem and progenitor cells (HSPCs) drives individual context-dependent programs of malignant transformation. In light of the various differentiation stages of HSPCs based on a recently revised definition using CD150/CD48, our analyses showed that a subpopulation of long-term-repopulating HSCs was most susceptible to MLL-ENL-mediated transformation. An analysis of the molecular mechanism identified Bromo-adjacent homology domain and coiled-coil containing 1 (Bahcc1), which encodes a reader molecule of trimethylated histone H3 lysine 27 (H3K27me3), as a candidate gene involved in distinct susceptibility to leukemic transformation. Interestingly, Bahcc1 was previously reported to be highly expressed in acute myeloid leukemia (AML) with an unfavorable prognosis, including some cases of MLL-rearranged AML. We found that MLL-ENL upregulated Bahcc1 through binding to its promoter, and that Bahcc1 was involved in MLL-ENL-mediated immortalization at least partly through repression of H3K27me3-marked Cdkn1c. Analyses using bone marrow transplantation in mice showed that depletion of Bahcc1 suppressed the leukemogenic activity of MLL-ENL. In a public database, high BAHCC1 expression was associated with a poor prognosis in pediatric AML, in which BAHCC1 expression was significantly lower in MLL-AF9-AML than in other MLL-fusion-AML. These findings shed light on the distinct immortalization potential of HSPCs and suggest a novel MLL-fusion-Bahcc1 axis, which may lead to development of molecular targeted therapy against MLL-fusion-mediated leukemia.
    DOI:  https://doi.org/10.1182/bloodadvances.2023011320
  12. Haematologica. 2024 Mar 07.
    Hematopoietic stem cell fate under the influence of Ser/Thr protein phosphatases.
    Meritxell Alberich-Jorda, Libor Macurek.
      Not available.
    DOI:  https://doi.org/10.3324/haematol.2024.285040
  13. Haematologica. 2024 Mar 07.
    Small extracellular vesicles derived from acute myeloid leukemia cells promote leukemogenesis by transferring miR-221-3p.
    Mengyu Li, Guohuan Sun, Jinlian Zhao, Shuangshuang Pu, Yanling Lv, Yifei Wang, Yapu Li, Xiangnan Zhao, Yajie Wang, Shangda Yang, Tao Cheng, Hui Cheng.
      Small extracellular vesicles (sEVs) transfer cargos between cells and participate in various physiological and pathological processes through their autocrine and paracrine effects. However, the pathological mechanisms employed by sEV-encapsulated microRNAs (miRNAs) in acute myeloid leukemia (AML) are still obscure. In this study, we aimed to investigate the effects of AML cells-derived sEVs (AML-sEVs) on AML cells and delineate the underlying mechanisms. We initially used high-throughput sequencing to identify miR-221-3p as the miRNA prominently enriched in AML-sEVs. Our findings revealed that miR-221-3p promoted AML cell proliferation and leukemogenesis by accelerating cell cycle entry and inhibiting apoptosis. Furthermore, Gbp2 was confirmed as a target gene of miR-221-3p by dual luciferase reporter assays and rescue experiments. Additionally, AML-sEVs impaired the clonogenicity, particularly the erythroid differentiation ability, of hematopoietic stem and progenitor cells. Taken together, our findings reveal how sEVs-delivered miRNAs contribute to AML pathogenesis, which can be exploited as a potential therapeutic target to attenuate AML progression.
    DOI:  https://doi.org/10.3324/haematol.2023.284145
  14. Int J Lab Hematol. 2024 Mar 08.
    Immunophenotypic characterization of leukemic stem cells in acute myeloid leukemia using single tube 10-colour panel by multiparametric flow cytometry: Deciphering the spectrum, complexity and immunophenotypic heterogeneity.
    Nupur Das, Devasis Panda, Smeeta Gajendra, Ritu Gupta, Deepshi Thakral, Gurvinder Kaur, Aafreen Khan, Vivek Kumar Singh, Arushi Vemprala, Sameer Bakhshi, Rachna Seth, Ranjit Kumar Sahoo, Atul Sharma, Sandeep Rai, Vijay K Prajapati, Saroj Singh.
       INTRODUCTION: Despite extensive research, comprehensive characterization of leukaemic stem cells (LSC) and information on their immunophenotypic differences from normal haematopoietic stem cells (HSC) is lacking. Herein, we attempted to unravel the immunophenotypic (IPT) characteristics and heterogeneity of LSC using multiparametric flow cytometry (MFC) and single-cell sequencing.
    MATERIALS AND METHODS: Bone marrow aspirate samples from patients with acute myeloid leukaemia (AML) were evaluated using MFC at diagnostic and post induction time points using a single tube-10-colour-panel containing LSC-associated antibodies CD123, CD45RA, CD44, CD33 and COMPOSITE (CLL-1, TIM-3, CD25, CD11b, CD22, CD7, CD56) with backbone markers that is, CD45, CD34, CD38, CD117, sCD3. Single-cell sequencing of the whole transcriptome was also done in a bone marrow sample.
    RESULTS: LSCs and HSCs were identified in 225/255 (88.2%) and 183/255 (71.6%) samples, respectively. Significantly higher expression was noted for COMPOSITE, CD45RA, CD123, CD33, and CD44 in LSCs than HSCs (p < 0.0001). On comparing the LSC specific antigen expressions between CD34+ (n = 184) and CD34- LSCs (n = 41), no difference was observed between the groups. More than one sub-population of LSC was demonstrated in 4.4% of cases, which further revealed high concordance between MFC and single cell transcriptomic analysis in one of the cases displaying three LSC subpopulations by both methods.
    CONCLUSION: A single tube-10-colour MFC panel is proposed as an easy and reproducible tool to identify and discriminate LSCs from HSCs. LSCs display both inter- and intra-sample heterogeneity in terms of antigen expressions, which opens the facets for single cell molecular analysis to elucidate the role of subpopulations of LSCs in AML progression.
    Keywords:  acute myeloid leukaemia; flow cytometry; leukaemic stem cells; single cell sequencing
    DOI:  https://doi.org/10.1111/ijlh.14250
  15. J Zhejiang Univ Sci B. 2024 Mar 15. pii: 1673-1581(2024)03-0212-21. [Epub ahead of print]25(3): 212-232
    Advances in the study of protein folding and endoplasmic reticulum-associated degradation in mammal cells.
    Hong Cao, Xuchang Zhou, Bowen Xu, Han Hu, Jianming Guo, Yuwei Ma, Miao Wang, Nan Li, Zou Jun.
      The endoplasmic reticulum is a key site for protein production and quality control. More than one-third of proteins are synthesized and folded into the correct three-dimensional conformation in the endoplasmic reticulum. However, during protein folding, unfolded and/or misfolded proteins are prone to occur, which may lead to endoplasmic reticulum stress. Organisms can monitor the quality of the proteins produced by endoplasmic reticulum quality control (ERQC) and endoplasmic reticulum-associated degradation (ERAD), which maintain endoplasmic reticulum protein homeostasis by degrading abnormally folded proteins. The underlying mechanisms of protein folding and ERAD in mammals have not yet been fully explored. Therefore, this paper reviews the process and function of protein folding and ERAD in mammalian cells, in order to help clinicians better understand the mechanism of ERAD and to provide a scientific reference for the treatment of diseases caused by abnormal ERAD.
    Keywords:  Endoplasmic reticulum-associated degradation (ERAD); Protein folding; Retrotranslocation; Ubiquitination
    DOI:  https://doi.org/10.1631/jzus.B2300403
  16. Exp Hematol. 2024 Mar 01. pii: S0301-472X(24)00051-1. [Epub ahead of print] 104192
    Biomaterials-assisted therapeutic cell production and modification in vivo.
    Kai Dai, Jing Wang, Changsheng Liu.
      Hematopoietic stem cell transplantation (HSCT) remains the preferred treatment for a variety of hematopoietic function disorders. To address the issue of limited numbers of hematopoietic stem/progenitor cells (HSPCs), significant progress has been made in the technology for ex vivo expansion of HSPCs. In addition, the biomaterials-assisted in vivo production technology for therapeutic cells, including HSPCs, is gradually gaining attention. With the aid of specifically functional biomaterials, researchers can construct bone-like tissues exhibiting typical bone marrow-like structures (termed in vivo osteo-organoids in this article) for the production of therapeutic cells. These in vivo osteo-organoids mimic the native bone marrow niche and provide a microenvironment conducive to the expansion and differentiation of HSPCs. In this perspective article, we systematically summarize the history of in vivo osteo-organoids as a model for studying hematopoiesis and cancer metastasis, and propose the challenges faced by the in vivo osteo-organoid production platform for therapeutic cells in terms of clinical translation. Ultimately, we hope to achieve functional customization of in vivo osteo-organoid derived cells through continuously developed material design methods, so as to meet the treatment needs of different types of diseases and bring hope for life to more people.
    Keywords:  biomaterials; cancer metastasis; hematopoiesis; hematopoietic stem/progenitor cells; in vivo osteo-organoid; therapeutic cells
    DOI:  https://doi.org/10.1016/j.exphem.2024.104192
  17. Immunity. 2024 Mar 05. pii: S1074-7613(24)00082-7. [Epub ahead of print]
    Differentiation route determines the functional outputs of adult megakaryopoiesis.
    Jing-Jing Li, Jingkun Liu, Yunqian Evelyn Li, Lin Veronica Chen, Hui Cheng, Yueying Li, Tao Cheng, Qian-Fei Wang, Bo O Zhou.
      Emerging evidence has revealed a direct differentiation route from hematopoietic stem cells to megakaryocytes (direct route), in addition to the classical differentiation route through a series of restricted hematopoietic progenitors (stepwise route). This raises the question of the importance of two alternative routes for megakaryopoiesis. Here, we developed fate-mapping systems to distinguish the two routes, comparing their quantitative and functional outputs. We found that megakaryocytes were produced through the two routes with comparable kinetics and quantity under homeostasis. Single-cell RNA sequencing of the fate-mapped megakaryocytes revealed that the direct and stepwise routes contributed to the niche-supporting and immune megakaryocytes, respectively, but contributed to the platelet-producing megakaryocytes together. Megakaryocytes derived from the two routes displayed different activities and were differentially regulated by chemotherapy and inflammation. Our work links differentiation route to the heterogeneity of megakaryocytes. Alternative differentiation routes result in variable combinations of functionally distinct megakaryocyte subpopulations poised for different physiological demands.
    Keywords:  cellular heterogeneity; differentiation; hematopoiesis; hematopoietic stem cell; immune response; lineage tracing; megakaryocyte; megakaryopoiesis; platelet; restricted progenitor
    DOI:  https://doi.org/10.1016/j.immuni.2024.02.006
  18. Nat Commun. 2024 Mar 08. 15(1): 2149
    Viscosity-dependent control of protein synthesis and degradation.
    Yuping Chen, Jo-Hsi Huang, Connie Phong, James E Ferrell.
      It has been proposed that the concentration of proteins in the cytoplasm maximizes the speed of important biochemical reactions. Here we have used Xenopus egg extracts, which can be diluted or concentrated to yield a range of cytoplasmic protein concentrations, to test the effect of cytoplasmic concentration on mRNA translation and protein degradation. We find that protein synthesis rates are maximal in ~1x cytoplasm, whereas protein degradation continues to rise to a higher optimal concentration of ~1.8x. We show that this difference in optima can be attributed to a greater sensitivity of translation to cytoplasmic viscosity. The different concentration optima could produce a negative feedback homeostatic system, where increasing the cytoplasmic protein concentration above the 1x physiological level increases the viscosity of the cytoplasm, which selectively inhibits translation and drives the system back toward the 1x set point.
    DOI:  https://doi.org/10.1038/s41467-024-46447-w
  19. Nat Commun. 2024 Mar 02. 15(1): 1949
    Cytokinetic abscission requires actin-dependent microtubule severing.
    Tamara Advedissian, Stéphane Frémont, Arnaud Echard.
      Cell division is completed by the abscission of the intercellular bridge connecting the daughter cells. Abscission requires the polymerization of an ESCRT-III cone close to the midbody to both recruit the microtubule severing enzyme spastin and scission the plasma membrane. Here, we found that the microtubule and the membrane cuts are two separate events that are regulated differently. Using HeLa cells, we uncovered that the F-actin disassembling protein Cofilin-1 controls the disappearance of a transient pool of branched F-actin which is precisely assembled at the tip of the ESCRT-III cone shortly before the microtubule cut. Functionally, Cofilin-1 and Arp2/3-mediated branched F-actin favor abscission by promoting local severing of the microtubules but do not participate later in the membrane scission event. Mechanistically, we propose that branched F-actin functions as a physical barrier that limits ESCRT-III cone elongation and thereby favors stable spastin recruitment. Our work thus reveals that F-actin controls the timely and local disassembly of microtubules required for cytokinetic abscission.
    DOI:  https://doi.org/10.1038/s41467-024-46062-9
  20. iScience. 2024 Mar 15. 27(3): 109302
    Mapping the substrate landscape of protein phosphatase 2A catalytic subunit PPP2CA.
    Abigail Brewer, Gajanan Sathe, Billie E Pflug, Rosemary G Clarke, Thomas J Macartney, Gopal P Sapkota.
      Protein phosphatase 2A (PP2A) is an essential Ser/Thr phosphatase. The PP2A holoenzyme complex comprises a scaffolding (A), regulatory (B), and catalytic (C) subunit, with PPP2CA being the principal catalytic subunit. The full scope of PP2A substrates in cells remains to be defined. To address this, we employed dTAG proteolysis-targeting chimeras to efficiently and selectively degrade dTAG-PPP2CA in homozygous knock-in HEK293 cells. Unbiased global phospho-proteomics identified 2,204 proteins with significantly increased phosphorylation upon dTAG-PPP2CA degradation, implicating them as potential PPP2CA substrates. A vast majority of these are novel. Bioinformatic analyses revealed involvement of the potential PPP2CA substrates in spliceosome function, cell cycle, RNA transport, and ubiquitin-mediated proteolysis. We identify a pSP/pTP motif as a predominant target for PPP2CA and confirm some of our phospho-proteomic data with immunoblotting. We provide an in-depth atlas of potential PPP2CA substrates and establish targeted degradation as a robust tool to unveil phosphatase substrates in cells.
    Keywords:  Enzymology; Properties of biomolecules; Protein; Proteomics
    DOI:  https://doi.org/10.1016/j.isci.2024.109302
  21. Cell Rep. 2024 Mar 07. pii: S2211-1247(24)00213-4. [Epub ahead of print]43(3): 113885
    Identification of molecular signatures defines the differential proteostasis response in induced spinal and cranial motor neurons.
    Ana Paula Zen Petisco Fiore, Shuvadeep Maity, Lauren Jeffery, Disi An, Justin Rendleman, Dylan Iannitelli, Hyungwon Choi, Esteban Mazzoni, Christine Vogel.
      Amyotrophic lateral sclerosis damages proteostasis, affecting spinal and upper motor neurons earlier than a subset of cranial motor neurons. To aid disease understanding, we exposed induced cranial and spinal motor neurons (iCrMNs and iSpMNs) to proteotoxic stress, under which iCrMNs showed superior survival, quantifying the transcriptome and proteome for >8,200 genes at 0, 12, and 36 h. Two-thirds of the proteome showed cell-type differences. iSpMN-enriched proteins related to DNA/RNA metabolism, and iCrMN-enriched proteins acted in the endoplasmic reticulum (ER)/ER chaperone complex, tRNA aminoacylation, mitochondria, and the plasma/synaptic membrane, suggesting that iCrMNs expressed higher levels of proteins supporting proteostasis and neuronal function. When investigating the increased proteasome levels in iCrMNs, we showed that the activity of the 26S proteasome, but not of the 20S proteasome, was higher in iCrMNs than in iSpMNs, even after a stress-induced decrease. We identified Ublcp1 as an iCrMN-specific regulator of the nuclear 26S activity.
    Keywords:  CP: Cell biology; CP: Neuroscience; Ublcp1; amyotrophic lateral sclerosis; motor neurons; proteasome; unfolded protein response
    DOI:  https://doi.org/10.1016/j.celrep.2024.113885
  22. Front Mol Biosci. 2024 ;11 1354682
    Kinase signalling adaptation supports dysfunctional mitochondria in disease.
    George L Skalka, Mina Tsakovska, Daniel J Murphy.
      Mitochondria form a critical control nexus which are essential for maintaining correct tissue homeostasis. An increasing number of studies have identified dysregulation of mitochondria as a driver in cancer. However, which pathways support and promote this adapted mitochondrial function? A key hallmark of cancer is perturbation of kinase signalling pathways. These pathways include mitogen activated protein kinases (MAPK), lipid secondary messenger networks, cyclic-AMP-activated (cAMP)/AMP-activated kinases (AMPK), and Ca2+/calmodulin-dependent protein kinase (CaMK) networks. These signalling pathways have multiple substrates which support initiation and persistence of cancer. Many of these are involved in the regulation of mitochondrial morphology, mitochondrial apoptosis, mitochondrial calcium homeostasis, mitochondrial associated membranes (MAMs), and retrograde ROS signalling. This review will aim to both explore how kinase signalling integrates with these critical mitochondrial pathways and highlight how these systems can be usurped to support the development of disease. In addition, we will identify areas which require further investigation to fully understand the complexities of these regulatory interactions. Overall, this review will emphasize how studying the interaction between kinase signalling and mitochondria improves our understanding of mitochondrial homeostasis and can yield novel therapeutic targets to treat disease.
    Keywords:  apoptosis; disease adaptation; kinase; mitochondria; mitochondrial associated endoplasmic reticulum membranes (MAMs); mitochondrial morphology; reactive oxygen species (ROS)
    DOI:  https://doi.org/10.3389/fmolb.2024.1354682
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