1
|
Genetically modified hematopoietic stem/progenitor cells that produce IL-10-secreting regulatory T cells. Proc Natl Acad Sci U S A 2019; 116:2634-2639. [PMID: 30683721 DOI: 10.1073/pnas.1811984116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Random amino acid copolymers used in the treatment of multiple sclerosis in man or experimental autoimmune encephalomyelitis (EAE) in mice [poly(Y,E,A,K)n, known as Copaxone, and poly(Y,F,A,K)n] function at least in part by generation of IL-10-secreting regulatory T cells that mediate bystander immunosuppression. The mechanism through which these copolymers induce Tregs is unknown. To investigate this question, four previously described Vα3.2 Vβ14 T cell receptor (TCR) cDNAs, the dominant clonotype generated in splenocytes after immunization of SJL mice, that differed only in their CDR3 sequences were utilized to generate retrogenic mice. The high-level production of IL-10 as well as IL-5 and small amounts of the related cytokines IL-4 and IL-13 by CD4+ T cells isolated from the splenocytes of these mice strongly suggests that the TCR itself encodes information for specific cytokine secretion. The proliferation and production of IL-10 by these Tregs was costimulated by activation of glucocorticoid-induced TNF receptor (GITR) (expressed at high levels by these cells) through its ligand GITRL. A mechanism for generation of cells with this specificity is proposed. Moreover, retrogenic mice expressing these Tregs were protected from induction of EAE by the appropriate autoantigen.
Collapse
|
2
|
HuR regulates telomerase activity through TERC methylation. Nat Commun 2018; 9:2213. [PMID: 29880812 PMCID: PMC5992219 DOI: 10.1038/s41467-018-04617-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 05/07/2018] [Indexed: 01/21/2023] Open
Abstract
Telomerase consists of the catalytic protein TERT and the RNA TERC. Mutations in TERC are linked to human diseases, but the underlying mechanisms are poorly understood. Here we report that the RNA-binding protein HuR associates with TERC and promotes the assembly of the TERC/TERT complex by facilitating TERC C106 methylation. Dyskeratosis congenita (DC)-related TERC U100A mutation impair the association of HuR with TERC, thereby reducing C106 methylation. Two other TERC mutations linked to aplastic anemia and autosomal dominant DC, G107U, and GC107/108AG, likewise disrupt methylation at C106. Loss-of-HuR binding and hence lower TERC methylation leads to decreased telomerase activity and telomere shortening. Furthermore, HuR deficiency or mutation of mTERC HuR binding or methylation sites impair the renewal of mouse hematopoietic stem cells, recapitulating the bone marrow failure seen in DC. Collectively, our findings reveal a novel function of HuR, linking HuR to telomerase function and TERC-associated DC. Mutations in the RNA component TERC can cause telomerase dysfunction but the underlying mechanisms are largely unknown. Here, the authors show that RNA-binding protein HuR regulates telomerase function by enhancing the methylation of TERC, which is impaired by several disease-relevant TERC mutations.
Collapse
|
3
|
Safdar A, Khrapko K, Flynn JM, Saleem A, De Lisio M, Johnston APW, Kratysberg Y, Samjoo IA, Kitaoka Y, Ogborn DI, Little JP, Raha S, Parise G, Akhtar M, Hettinga BP, Rowe GC, Arany Z, Prolla TA, Tarnopolsky MA. Exercise-induced mitochondrial p53 repairs mtDNA mutations in mutator mice. Skelet Muscle 2016; 6:7. [PMID: 26834962 PMCID: PMC4733510 DOI: 10.1186/s13395-016-0075-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 01/05/2016] [Indexed: 11/22/2022] Open
Abstract
Background Human genetic disorders and transgenic mouse models have shown that mitochondrial DNA (mtDNA) mutations and telomere dysfunction instigate the aging process. Epidemiologically, exercise is associated with greater life expectancy and reduced risk of chronic diseases. While the beneficial effects of exercise are well established, the molecular mechanisms instigating these observations remain unclear. Results Endurance exercise reduces mtDNA mutation burden, alleviates multisystem pathology, and increases lifespan of the mutator mice, with proofreading deficient mitochondrial polymerase gamma (POLG1). We report evidence for a POLG1-independent mtDNA repair pathway mediated by exercise, a surprising notion as POLG1 is canonically considered to be the sole mtDNA repair enzyme. Here, we show that the tumor suppressor protein p53 translocates to mitochondria and facilitates mtDNA mutation repair and mitochondrial biogenesis in response to endurance exercise. Indeed, in mutator mice with muscle-specific deletion of p53, exercise failed to prevent mtDNA mutations, induce mitochondrial biogenesis, preserve mitochondrial morphology, reverse sarcopenia, or mitigate premature mortality. Conclusions Our data establish a new role for p53 in exercise-mediated maintenance of the mtDNA genome and present mitochondrially targeted p53 as a novel therapeutic modality for diseases of mitochondrial etiology. Electronic supplementary material The online version of this article (doi:10.1186/s13395-016-0075-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Adeel Safdar
- Department of Kinesiology, McMaster University, Hamilton, ON L8N 3Z5 Canada ; Department of Pediatrics, McMaster University, Hamilton, ON L8N 3Z5 Canada ; Department of Medicine, McMaster University, Hamilton, ON L8N 3Z5 Canada
| | | | - James M Flynn
- Buck Institute for Research on Aging, Novato, CA 94945 USA
| | - Ayesha Saleem
- Department of Pediatrics, McMaster University, Hamilton, ON L8N 3Z5 Canada
| | - Michael De Lisio
- Department of Kinesiology, McMaster University, Hamilton, ON L8N 3Z5 Canada
| | - Adam P W Johnston
- Department of Kinesiology, McMaster University, Hamilton, ON L8N 3Z5 Canada
| | | | - Imtiaz A Samjoo
- Department of Medical Sciences, McMaster University, Hamilton, ON L8N 3Z5 Canada
| | - Yu Kitaoka
- Department of Pediatrics, McMaster University, Hamilton, ON L8N 3Z5 Canada
| | - Daniel I Ogborn
- Department of Medical Sciences, McMaster University, Hamilton, ON L8N 3Z5 Canada
| | - Jonathan P Little
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC V1V 1V7 Canada
| | - Sandeep Raha
- Department of Pediatrics, McMaster University, Hamilton, ON L8N 3Z5 Canada
| | - Gianni Parise
- Department of Kinesiology, McMaster University, Hamilton, ON L8N 3Z5 Canada ; Department of Medical Physics & Applied Radiation Sciences, McMaster University, Hamilton, ON L8N 3Z5 Canada
| | - Mahmood Akhtar
- Department of Medicine, McMaster University, Hamilton, ON L8N 3Z5 Canada
| | - Bart P Hettinga
- Department of Pediatrics, McMaster University, Hamilton, ON L8N 3Z5 Canada
| | - Glenn C Rowe
- Division of Cardiovascular Disease, University of Alabama, Birmingham, AL 35294 USA
| | - Zoltan Arany
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Tomas A Prolla
- Departments of Genetics, University of Wisconsin, Madison, WI 53706 USA ; Departments of Medical Genetics, University of Wisconsin, Madison, WI 53706 USA
| | - Mark A Tarnopolsky
- Department of Pediatrics, McMaster University, Hamilton, ON L8N 3Z5 Canada ; Department of Medicine, McMaster University, Hamilton, ON L8N 3Z5 Canada
| |
Collapse
|
4
|
Nagamachi A, Htun PW, Ma F, Miyazaki K, Yamasaki N, Kanno M, Inaba T, Honda ZI, Okuda T, Oda H, Tsuji K, Honda H. A 5' untranslated region containing the IRES element in the Runx1 gene is required for angiogenesis, hematopoiesis and leukemogenesis in a knock-in mouse model. Dev Biol 2010; 345:226-36. [PMID: 20647008 DOI: 10.1016/j.ydbio.2010.07.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 07/11/2010] [Accepted: 07/13/2010] [Indexed: 12/24/2022]
Abstract
Although internal ribosome entry site (IRES)-mediated translation is considered important for proper cellular function, its precise biological role is not fully understood. Runx1 gene, which encodes a transcription factor implicated in hematopoiesis, angiogenesis, and leukemogenesis, contains IRES sequences in the 5' untranslated region. To clarify the roles of the IRES element in Runx1 function, we generated knock-in mice for either wild-type Runx1 or Runx1/Evi1, a Runx1 fusion protein identified in human leukemia. In both cases, native promoter-dependent transcription was retained, whereas IRES-mediated translation was eliminated. Interestingly, homozygotes expressing wild-type Runx1 deleted for the IRES element (Runx1(Delta IRES/Delta IRES)) died in utero with prominent dilatation of peripheral blood vessels due to impaired pericyte development. In addition, hematopoietic cells in the Runx1(Delta IRES/Delta IRES) fetal liver were significantly decreased, and exhibited an altered differentiation pattern, a reduced proliferative activity, and an impaired reconstitution ability. On the other hand, heterozygotes expressing Runx1/Evi1 deleted for the IRES element (Runx1(+/RE Delta IRES)) were born normally and did not show any hematological abnormalities, in contrast that conventional Runx1/Evi1 heterozygotes die in utero with central nervous system hemorrhage and Runx1/Evi1 chimeric mice develop acute leukemia. The findings reported here demonstrate the essential roles of the IRES element in Runx1 function under physiological and pathological conditions.
Collapse
Affiliation(s)
- Akiko Nagamachi
- Department of Molecular Oncology, Research Institute of Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Morita Y, Ema H, Yamazaki S, Nakauchi H. Non-side-population hematopoietic stem cells in mouse bone marrow. Blood 2006; 108:2850-6. [PMID: 16804114 DOI: 10.1182/blood-2006-03-010207] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Most hematopoietic stem cells (HSCs) are assumed to reside in the so-called side population (SP) in adult mouse bone marrow (BM). We report the coexistence of non-SP HSCs that do not significantly differ from SP HSCs in numbers, capacities, and cell-cycle states. When stained with Hoechst 33342 dye, the CD34(-/low) c-Kit(+)Sca-1(+)lineage marker(-) (CD34(-)KSL) cell population, highly enriched in mouse HSCs, was almost equally divided into the SP and the main population (MP) that represents non-SP cells. Competitive repopulation assays with single or 30 SP- or MP-CD34(-)KSL cells found similar degrees of repopulating activity and frequencies of repopulating cells for these populations. Secondary transplantation detected self-renewal capacity in both populations. SP analysis of BM cells from primary recipient mice suggested that the SP and MP phenotypes are interconvertible. Cell-cycle analyses revealed that CD34(-)KSL cells were in a quiescent state and showed uniform cell-cycle kinetics, regardless of whether they were in the SP or MP. Bcrp-1 expression was similarly detected in SP- and MP-CD34(-)KSL cells, suggesting that the SP phenotype is regulated not only by Bcrp-1, but also by other factors. The SP phenotype does not specify all HSCs; its identity with stem cell function thus is unlikely.
Collapse
Affiliation(s)
- Yohei Morita
- Laboratory of Stem Cell Therapy, Center for Experimental Medicine, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639 Japan
| | | | | | | |
Collapse
|