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Heazlewood SY, Ahmad T, Cao B, Cao H, Domingues M, Sun X, Heazlewood CK, Li S, Williams B, Fulton M, White JF, Nebl T, Nefzger CM, Polo JM, Kile BT, Kraus F, Ryan MT, Sun YB, Choong PFM, Ellis SL, Anko ML, Nilsson SK. High ploidy large cytoplasmic megakaryocytes are hematopoietic stem cells regulators and essential for platelet production. Nat Commun 2023; 14:2099. [PMID: 37055407 PMCID: PMC10102126 DOI: 10.1038/s41467-023-37780-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 03/30/2023] [Indexed: 04/15/2023] Open
Abstract
Megakaryocytes (MK) generate platelets. Recently, we and others, have reported MK also regulate hematopoietic stem cells (HSC). Here we show high ploidy large cytoplasmic megakaryocytes (LCM) are critical negative regulators of HSC and critical for platelet formation. Using a mouse knockout model (Pf4-Srsf3Δ/Δ) with normal MK numbers, but essentially devoid of LCM, we demonstrate a pronounced increase in BM HSC concurrent with endogenous mobilization and extramedullary hematopoiesis. Severe thrombocytopenia is observed in animals with diminished LCM, although there is no change in MK ploidy distribution, uncoupling endoreduplication and platelet production. When HSC isolated from a microenvironment essentially devoid of LCM reconstitute hematopoiesis in lethally irradiated mice, the absence of LCM increases HSC in BM, blood and spleen, and the recapitulation of thrombocytopenia. In contrast, following a competitive transplant using minimal numbers of WT HSC together with HSC from a microenvironment with diminished LCM, sufficient WT HSC-generated LCM regulates a normal HSC pool and prevents thrombocytopenia. Importantly, LCM are conserved in humans.
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Affiliation(s)
- Shen Y Heazlewood
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
| | - Tanveer Ahmad
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
| | - Benjamin Cao
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
| | - Huimin Cao
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
| | - Melanie Domingues
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
| | - Xuan Sun
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
| | - Chad K Heazlewood
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
| | - Songhui Li
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
| | - Brenda Williams
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
| | - Madeline Fulton
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
| | - Jacinta F White
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
| | - Tom Nebl
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia
| | - Christian M Nefzger
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Jose M Polo
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
- Monash Biomedicine Discovery Institute, Melbourne, VIC, Australia
| | - Benjamin T Kile
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Felix Kraus
- Monash Biomedicine Discovery Institute, Melbourne, VIC, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, Australia
| | - Michael T Ryan
- Monash Biomedicine Discovery Institute, Melbourne, VIC, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, Australia
| | - Yu B Sun
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
- Monash Biomedicine Discovery Institute, Melbourne, VIC, Australia
| | - Peter F M Choong
- Department of Surgery, St. Vincent's Hospital, University of Melbourne, Melbourne, VIC, Australia
- Bone and Soft Tissue Sarcoma Service, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
- Department of Orthopaedics, St. Vincent's Hospital Melbourne, Melbourne, VIC, Australia
| | - Sarah L Ellis
- Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
- The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC, Australia
| | - Minna-Liisa Anko
- Centre for Reproductive Health and Centre for Cancer Research, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Molecular and Translational Science, Monash University, Melbourne, VIC, Australia
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Susan K Nilsson
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organization, Melbourne, VIC, Australia.
- Australian Regenerative Medicine Institute, Monash University, Melbourne, VIC, Australia.
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Ratnadiwakara M, Archer SK, Dent CI, Ruiz De Los Mozos I, Beilharz TH, Knaupp AS, Nefzger CM, Polo JM, Anko ML. SRSF3 promotes pluripotency through Nanog mRNA export and coordination of the pluripotency gene expression program. eLife 2018; 7:37419. [PMID: 29741478 PMCID: PMC5963917 DOI: 10.7554/elife.37419] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/05/2018] [Indexed: 12/28/2022] Open
Abstract
The establishment and maintenance of pluripotency depend on precise coordination of gene expression. We establish serine-arginine-rich splicing factor 3 (SRSF3) as an essential regulator of RNAs encoding key components of the mouse pluripotency circuitry, SRSF3 ablation resulting in the loss of pluripotency and its overexpression enhancing reprogramming. Strikingly, SRSF3 binds to the core pluripotency transcription factor Nanog mRNA to facilitate its nucleo-cytoplasmic export independent of splicing. In the absence of SRSF3 binding, Nanog mRNA is sequestered in the nucleus and protein levels are severely downregulated. Moreover, SRSF3 controls the alternative splicing of the export factor Nxf1 and RNA regulators with established roles in pluripotency, and the steady-state levels of mRNAs encoding chromatin modifiers. Our investigation links molecular events to cellular functions by demonstrating how SRSF3 regulates the pluripotency genes and uncovers SRSF3-RNA interactions as a critical means to coordinate gene expression during reprogramming, stem cell self-renewal and early development.
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Affiliation(s)
- Madara Ratnadiwakara
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Stuart K Archer
- Bioinformatics Platform, Monash University, Clayton, Australia
| | - Craig I Dent
- School of Biological Sciences, Monash University, Melbourne, Australia
| | | | - Traude H Beilharz
- Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia
| | - Anja S Knaupp
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Christian M Nefzger
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Jose M Polo
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
| | - Minna-Liisa Anko
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Melbourne, Australia.,Australian Regenerative Medicine Institute, Monash University, Clayton, Australia
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Kim EJY, Anko ML, Flensberg C, Majewski IJ, Geng FS, Firas J, Huang DCS, van Delft MF, Heath JK. BAK/BAX-Mediated Apoptosis Is a Myc-Induced Roadblock to Reprogramming. Stem Cell Reports 2018; 10:331-338. [PMID: 29358089 PMCID: PMC5830948 DOI: 10.1016/j.stemcr.2017.12.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 12/21/2017] [Accepted: 12/21/2017] [Indexed: 12/15/2022] Open
Abstract
Despite intensive efforts to optimize the process, reprogramming differentiated cells to induced pluripotent stem cells (iPSCs) remains inefficient. The most common combination of transcription factors employed comprises OCT4, KLF4, SOX2, and MYC (OKSM). If MYC is omitted (OKS), reprogramming efficiency is reduced further. Cells must overcome several obstacles to reach the pluripotent state, one of which is apoptosis. To directly determine how extensively apoptosis limits reprogramming, we exploited mouse embryonic fibroblasts (MEFs) lacking the two essential mediators of apoptosis, BAK and BAX. Our results show that reprogramming is enhanced in MEFs deficient in BAK and BAX, but only when MYC is part of the reprogramming cocktail. Thus, the propensity for Myc overexpression to elicit apoptosis creates a significant roadblock to reprogramming under OKSM conditions. Our results suggest that blocking apoptosis during reprogramming may enhance the derivation of iPSCs for research and therapeutic purposes.
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Affiliation(s)
- Esther J Y Kim
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Minna-Liisa Anko
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Clayton, VIC 3800, Australia
| | - Christoffer Flensberg
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Ian J Majewski
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Fan-Suo Geng
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Jaber Firas
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Development and Stem Cells Program, Monash University, Clayton, VIC 3800, Australia
| | - David C S Huang
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Mark F van Delft
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia.
| | - Joan K Heath
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia.
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