1
|
Wu S, Yu Y, Liu C, Zhang X, Zhu P, Peng Y, Yan X, Li Y, Hua P, Li Q, Wang S, Zhang L. Single-cell transcriptomics reveals lineage trajectory of human scalp hair follicle and informs mechanisms of hair graying. Cell Discov 2022; 8:49. [PMID: 35606346 PMCID: PMC9126928 DOI: 10.1038/s41421-022-00394-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 03/01/2022] [Indexed: 02/03/2023] Open
Abstract
Hair conditions, such as hair loss and graying, are prevalent human conditions. But they are often poorly controlled due to our insufficient understanding of human scalp hair follicle (hsHF) in health and disease. Here we describe a comprehensive single-cell RNA-seq (scRNA-seq) analysis on highly purified black and early-stage graying hsHFs. Based on these, a concise single-cell atlas for hsHF and its early graying changes is generated and verified using samples from multiple independent individuals. These data reveal the lineage trajectory of hsHF in unprecedented detail and uncover its multiple unexpected features not found in mouse HFs, including the presence of an innerbulge like compartment in the growing phase, lack of a discrete companion layer, and enrichment of EMT features in HF stem cells (HFSCs). Moreover, we demonstrate that besides melanocyte depletion, early-stage human hair graying is also associated with specific depletion of matrix hair progenitors but not HFSCs. The hair progenitors' depletion is accompanied by their P53 pathway activation whose pharmaceutical blockade can ameliorate hair graying in mice, enlightening a promising therapeutic avenue for this prevalent hair condition.
Collapse
Affiliation(s)
- Sijie Wu
- CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, CAS, Shanghai, China
- Human Phenome Institute, Fudan University, 825 Zhangheng Road, Shanghai, China
- State Key Laboratory of Genetic Engineering and Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Yao Yu
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, CAS, Shanghai, China
| | - Caiyue Liu
- Department of Plastic & Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, China
| | - Xia Zhang
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, CAS, Shanghai, China
| | - Peiying Zhu
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, CAS, Shanghai, China
| | - You Peng
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, CAS, Shanghai, China
| | - Xinyu Yan
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, CAS, Shanghai, China
| | - Yin Li
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, CAS, Shanghai, China
| | - Peng Hua
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, CAS, Shanghai, China
| | - Qingfeng Li
- Department of Plastic & Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, China.
| | - Sijia Wang
- CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, CAS, Shanghai, China.
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, China.
| | - Liang Zhang
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, CAS, Shanghai, China.
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing, China.
| |
Collapse
|
2
|
Bhat FA, Advani J, Khan AA, Mohan S, Pal A, Gowda H, Chakrabarti P, Keshava Prasad TS, Chatterjee A. A network map of thrombopoietin signaling. J Cell Commun Signal 2018; 12:737-743. [PMID: 30039510 DOI: 10.1007/s12079-018-0480-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 07/05/2018] [Indexed: 10/28/2022] Open
Abstract
Thrombopoietin (THPO), also known as megakaryocyte growth and development factor (MGDF), is a cytokine involved in the production of platelets. THPO is a glycoprotein produced by liver and kidney. It regulates the production of platelets by stimulating the differentiation and maturation of megakaryocyte progenitors. It acts as a ligand for MPL receptor, a member of the hematopoietic cytokine receptor superfamily and is essential for megakaryocyte maturation. THPO binding induces homodimerization of the receptor which results in activation of JAKSTAT and MAPK signaling cascades that subsequently control cellular proliferation, differentiation and other signaling events. Despite the importance of THPO signaling in various diseases and biological processes, a detailed signaling network of THPO is not available in any publicly available database. Therefore, in this study, we present a resource of signaling events induced by THPO that was manually curated from published literature on THPO. Our manual curation of thrombopoietin pathway resulted in identification of 48 molecular associations, 66 catalytic reactions, 100 gene regulation events, 19 protein translocation events and 43 activation/inhibition reactions that occur upon activation of thrombopoietin receptor by THPO. THPO signaling pathway is made available on NetPath, a freely available human signaling pathway resource developed previously by our group. We believe this resource will provide a platform for scientific community to accelerate further research in this area on potential therapeutic interventions.
Collapse
Affiliation(s)
- Firdous A Bhat
- Institute of Bioinformatics, International Technology Park, Bangalore, 560 066, India.,School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam, 690525, India
| | - Jayshree Advani
- Institute of Bioinformatics, International Technology Park, Bangalore, 560 066, India.,Manipal Academy of Higher Education, Manipal, 576104, India
| | - Aafaque Ahmad Khan
- Institute of Bioinformatics, International Technology Park, Bangalore, 560 066, India.,School of Biotechnology, Kalinga Institute of Industrial Technology, Bhubaneswar, 751024, India
| | - Sonali Mohan
- Institute of Bioinformatics, International Technology Park, Bangalore, 560 066, India
| | - Arnab Pal
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh, 160012, India
| | - Harsha Gowda
- Institute of Bioinformatics, International Technology Park, Bangalore, 560 066, India
| | - Prantar Chakrabarti
- Department of Haematology, Nil Ratan Sircar Medical College and Hospital, Kolkata, 700014, India
| | - T S Keshava Prasad
- Institute of Bioinformatics, International Technology Park, Bangalore, 560 066, India. .,Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Mangalore, 575018, India.
| | - Aditi Chatterjee
- Institute of Bioinformatics, International Technology Park, Bangalore, 560 066, India.
| |
Collapse
|
3
|
He X, Chen Z, Jiang Y, Qiu X, Zhao X. Different mutations of the human c-mpl gene indicate distinct haematopoietic diseases. J Hematol Oncol 2013; 6:11. [PMID: 23351976 PMCID: PMC3563459 DOI: 10.1186/1756-8722-6-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 01/22/2013] [Indexed: 11/10/2022] Open
Abstract
The human c-mpl gene (MPL) plays an important role in the development of megakaryocytes and platelets as well as the self-renewal of haematopoietic stem cells. However, numerous MPL mutations have been identified in haematopoietic diseases. These mutations alter the normal regulatory mechanisms and lead to autonomous activation or signalling deficiencies. In this review, we summarise 59 different MPL mutations and classify these mutations into four different groups according to the associated diseases and mutation rates. Using this classification, we clearly distinguish four diverse types of MPL mutations and obtain a deep understand of their clinical significance. This will prove to be useful for both disease diagnosis and the design of individual therapy regimens based on the type of MPL mutations.
Collapse
Affiliation(s)
- Xin He
- Department of Hematology, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | | | | | | | | |
Collapse
|
4
|
Apostolidis PA, Lindsey S, Miller WM, Papoutsakis ET. Proposed megakaryocytic regulon of p53: the genes engaged to control cell cycle and apoptosis during megakaryocytic differentiation. Physiol Genomics 2012; 44:638-50. [PMID: 22548738 DOI: 10.1152/physiolgenomics.00028.2012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
During endomitosis, megakaryocytes undergo several rounds of DNA synthesis without division leading to polyploidization. In primary megakaryocytes and in the megakaryocytic cell line CHRF, loss or knock-down of p53 enhances cell cycling and inhibits apoptosis, leading to increased polyploidization. To support the hypothesis that p53 suppresses megakaryocytic polyploidization, we show that stable expression of wild-type p53 in K562 cells (a p53-null cell line) attenuates the cells' ability to undergo polyploidization during megakaryocytic differentiation due to diminished DNA synthesis and greater apoptosis. This suggested that p53's effects during megakaryopoiesis are mediated through cell cycle- and apoptosis-related target genes, possibly by arresting DNA synthesis and promoting apoptosis. To identify candidate genes through which p53 mediates these effects, gene expression was compared between p53 knock-down (p53-KD) and control CHRF cells induced to undergo terminal megakaryocytic differentiation using microarray analysis. Among substantially downregulated p53 targets in p53-KD megakaryocytes were cell cycle regulators CDKN1A (p21) and PLK2, proapoptotic FAS, TNFRSF10B, CASP8, NOTCH1, TP53INP1, TP53I3, DRAM1, ZMAT3 and PHLDA3, DNA-damage-related RRM2B and SESN1, and actin component ACTA2, while antiapoptotic CKS1B, BCL2, GTSE1, and p53 family member TP63 were upregulated in p53-KD cells. Additionally, a number of cell cycle-related, proapoptotic, and cytoskeleton-related genes with known functions in megakaryocytes but not known to carry p53-responsive elements were differentially expressed between p53-KD and control CHRF cells. Our data support a model whereby p53 expression during megakaryopoiesis serves to control polyploidization and the transition from endomitosis to apoptosis by impeding cell cycling and promoting apoptosis. Furthermore, we identify a putative p53 regulon that is proposed to orchestrate these effects.
Collapse
Affiliation(s)
- Pani A Apostolidis
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois, USA.
| | | | | | | |
Collapse
|
5
|
Role of tumor suppressor p53 in megakaryopoiesis and platelet function. Exp Hematol 2011; 40:131-42.e4. [PMID: 22024107 DOI: 10.1016/j.exphem.2011.10.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 10/09/2011] [Accepted: 10/11/2011] [Indexed: 11/23/2022]
Abstract
The pathobiological role of p53 has been widely studied, however, its role in normophysiology is relatively unexplored. We previously showed that p53 knock-down increased ploidy in megakaryocytic cultures. This study aims to examine the effect of p53 loss on in vivo megakaryopoiesis, platelet production, and function, and to investigate the basis for greater ploidy in p53(-/-) megakaryocytic cultures. Here, we used flow cytometry to analyze ploidy, DNA synthesis, and apoptosis in murine cultured and bone marrow megakaryocytes following thrombopoietin administration and to analyze fibrinogen binding to platelets in vitro. Culture of p53(-/-) marrow cells for 6 days with thrombopoietin gave rise to 1.7-fold more megakaryocytes, 26.1% ± 3.6% of which reached ploidy classes ≥64 N compared to 8.2% ± 0.9% of p53(+/+) megakaryocytes. This was due to 30% greater DNA synthesis in p53(-/-) megakaryocytes and 31% greater apoptosis in p53(+/+) megakaryocytes by day 4 of culture. Although the bone marrow and spleen steady-state megakaryocytic content and ploidy were similar in p53(+/+) and p53(-/-) mice, thrombopoietin administration resulted in increased megakaryocytic polyploidization in p53(-/-) mice. Although their platelet counts were normal, p53(-/-) mice exhibited significantly longer bleeding times and p53(-/-) platelets were less sensitive than p53(+/+) platelets to agonist-induced fibrinogen binding and P-selectin secretion. In summary, our in vivo and ex vivo studies indicate that p53 loss leads to increased polyploidization during megakaryopoiesis. Our findings also suggest for the first time a direct link between p53 loss and the development of fully functional platelets resulting in hemostatic deficiencies.
Collapse
|
6
|
Neuroprotective cytokines repress PUMA induction in the 1-methyl-4-phenylpyridinium (MPP(+)) model of Parkinson's disease. Biochem Biophys Res Commun 2011; 411:370-4. [PMID: 21741364 DOI: 10.1016/j.bbrc.2011.06.151] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 06/24/2011] [Indexed: 01/01/2023]
Abstract
The hematopoietic cytokines erythropoietin (Epo) and granulocyte-colony stimulating factor (G-CSF) provide neuroprotection in several in vitro and in vivo models of Parkinson's disease (PD). The molecular mechanism by which Epo and G-CSF signals reduce the neuronal death in PD is not clear. Here, we show that in rat pheochromocytoma PC12 cells, Epo and G-CSF efficiently repressed the 1-methyl-4-phenylpyridinium (MPP(+))-induced expression of the proapoptotic protein PUMA (p53 up-regulated modulator of apoptosis). Accordingly, Epo and G-CSF treatment reduced the PC12 cell fraction that underwent apoptosis by MPP(+) treatment and thus improved cell viability. Downregulation of PUMA expression by Epo and G-CSF in MPP(+)-treated PC12 cells seems to be mediated by repression of p53, as the expression of p53 was increased by MPP(+)-treatment and reduced by Epo and G-CSF. Together, these results suggest that the neuroprotective activities of Epo and G-CSF in an experimental model of PD involve the repression of the apoptosis-inducing action of PUMA.
Collapse
|
7
|
Antonchuk J, Hyland CD, Hilton DJ, Alexander WS. Synergistic effects on erythropoiesis, thrombopoiesis, and stem cell competitiveness in mice deficient in thrombopoietin and steel factor receptors. Blood 2004; 104:1306-13. [PMID: 15138166 DOI: 10.1182/blood-2004-04-1522] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The degree of redundancy between thrombopoietin (Tpo) and steel factor (SF) cytokine pathways in the regulation of hematopoiesis was investigated by generating mice lacking both c-Mpl and fully functional c-Kit receptors. Double-mutant c-Mpl(-/-)Kit(Wv/Wv) mice exhibited reduced viability, making up only 2% of the offspring from c-Mpl(-/-)Kit(Wv/)(+) intercrosses. The thrombocytopenia and megakaryocytopenia characteristic of c-Mpl(-/-) mice was unchanged in c-Mpl(-/-)Kit(Wv/Wv) mice. However, the number of megakaryocytic colony forming units (CFU-Mks) was significantly reduced, particularly in the spleen. While Kit(Wv/Wv) mice, but not c-Mpl(-/-) mice, are anemic, the anemia was more severe in double-mutant c-Mpl(-/-)Kit(Wv/Wv) mice, indicating redundancy between Tpo and SF in erythropoiesis. At the primitive cell level, c-Mpl(-/-) and Kit(Wv/Wv) mice have similar phenotypes, including reduced progenitors, colony forming units-spleen (CFU-Ss), and repopulating activities. All of these parameters were exacerbated in double-mutant mice. c-Mpl(-/-)Kit(Wv/Wv) mice had 8-fold fewer clonogenic progenitor cells and at least 28-fold fewer CFU-Ss. c-Mpl(-/-) mice also demonstrated a reduced threshold requirement for nonmyeloablative transplant repopulation, a trait previously associated only with Kit(W) mice, and the level of nonmyeloablative engraftment was significantly greater in c-Mpl(-/-) Kit(Wv/Wv) double mutants. Thus, c-Mpl(-/-) Kit(Wv/Wv) mice reveal nonredundant and synergistic effects of Tpo and SF on primitive hematopoietic cells.
Collapse
Affiliation(s)
- Jennifer Antonchuk
- Cancer and Haematology Division, Walter & Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia
| | | | | | | |
Collapse
|
8
|
Sigurjonsson OE, Gudmundsson KO, Haraldsdottir V, Rafnar T, Agnarsson BA, Gudmundsson S. Flt3/Flk-2 Ligand in Combination with Thrombopoietin Decreases Apoptosis in Megakaryocyte Development. Stem Cells Dev 2004; 13:183-91. [PMID: 15186734 DOI: 10.1089/154732804323046783] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The growth factors thrombopoietin (TPO) and Flt3/Flk-2-ligand (FL), either independently or in combination, modulate megakaryocyte development. Our results show that bone marrow CD34+ cells cultured with TPO and FL differentiate at a slower rate into CD41+ cells and are delayed in apoptosis at the later stages of the cultures compared to cells cultured with TPO alone. Our data also show that FL in synergy with TPO may inhibit apoptosis in megakaryocyte development by up-regulating bcl-2 and inducing conformational changes of p53, in MK progenitors. FL in combination with TPO slows down maturation and consequently delays apoptosis of MK progenitor cells.
Collapse
|
9
|
Lannutti BJ, Shim MH, Blake N, Reems JA, Drachman JG. Identification and activation of Src family kinases in primary megakaryocytes. Exp Hematol 2004; 31:1268-74. [PMID: 14662334 DOI: 10.1016/j.exphem.2003.09.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVES We have recently shown that the Src family of tyrosine kinases (SFKs) are activated by TPO stimulation in both primary megakaryocytic progenitors and a hematopoietic cells line (BaF3) expressing the TPO receptor (Mpl). In this study, we examine which of the eight Src family members are expressed in primary megakaryocytes (MKs) and determine which of these become activated in response to TPO. MATERIALS AND METHODS High-density oligonucleotide microarrays were used to compare the gene expression profiles of Src kinases from undifferentiated hematopoietic progenitors (CD34+/CD38(lo)) and after in vitro megakaryocytic differentiation. Western blot analysis of lysates from purified, mature murine MKs identified which of SFKs are present. Finally, in vitro kinase assays determined which of the SFKs in primary MKs are activated by TPO stimulation. RESULTS Array profiles demonstrate that Fyn, Lyn, Fgr, Hck, Src, and Yes are all expressed in cultured human MKs (Fyn, Lyn>Src, Yes, Fgr, Hck). Similarly, Western blots of murine MKs identified the same six SFKs (Fyn, Fgr, Hck, Lyn, Src, and Yes). Of these, only Fyn and Lyn demonstrate increased kinase activity after TPO stimulation. Interestingly, gene expression analysis indicates that, among the SFKs, Fyn expression is uniquely upregulated during MK development. CONCLUSION These results provide the first direct evidence that two Src kinases are activated in primary MKs, Fyn and Lyn. The fact that only Fyn expression is significantly upregulated during MK differentiation suggests variable gene regulation. Specificity of the TPO signaling cascade is demonstrated by the selective activation of Fyn and Lyn.
Collapse
Affiliation(s)
- Brian J Lannutti
- Puget Sound Blood Center, 921 Terry Avenue, Seattle, WA 98104-1256, USA.
| | | | | | | | | |
Collapse
|
10
|
Suzuki S, Chuang LF, Doi RH, Chuang RY. Morphine suppresses lymphocyte apoptosis by blocking p53-mediated death signaling. Biochem Biophys Res Commun 2003; 308:802-8. [PMID: 12927789 DOI: 10.1016/s0006-291x(03)01472-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Opiates such as morphine or heroin may promote cell apoptosis and cause dysfunction of immune cells. In simian immunodeficiency virus (SIV)-infected lymphocytic cells, however, morphine may protect the cells from apoptotic lysis and allow the virus to continue to replicate. To further explore this apparently antithetical effect of opiates, we evaluated in the present study the effects of morphine on human lymphocytic CEM x174 cells induced to undergo apoptosis in the presence of actinomycin D. It was found that induction of apoptosis (characterized by DNA laddering) by actinomycin D was accompanied by a stimulation of the expression of active (phosphorylated) form of p53. Pretreatment of the cells with 10nM morphine caused a transient, naloxone-reversible suppression of the appearance of activated p53 and the generation of DNA laddering. Parallel evaluation of the growth of CEM x174 indicated that morphine treatment delays the inception of cell death triggered by actinomycin D. Inasmuch as Bcl-2 suppresses while Bax accelerates apoptosis, treatment of cells with morphine reduced the expression of Bax and enhanced the expression of Bcl-2. Taken together, morphine, through binding at the opioid receptor, may protect lymphocytic cells from apoptotic lysis if cell death is initiated by apoptosis-inducing agents such as human immunodeficiency virus (HIV), SIV or actinomycin D.
Collapse
Affiliation(s)
- Shunji Suzuki
- Department of Medical Pharmacology and Toxicology, School of Medicine, University of California, Davis, CA 95616, USA
| | | | | | | |
Collapse
|
11
|
Abe M, Suzuki K, Inagaki O, Sassa S, Shikama H. A novel MPL point mutation resulting in thrombopoietin-independent activation. Leukemia 2002; 16:1500-6. [PMID: 12145691 DOI: 10.1038/sj.leu.2402554] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2002] [Accepted: 03/05/2002] [Indexed: 01/10/2023]
Abstract
Thrombopoietin (TPO) and its receptor (MPL) are important regulators of megakaryopoiesis. MPL belongs to a cytokine receptor superfamily. To date, all constitutively active MPL mutants have been artificially constructed with amino acid substitutions in the transmembrane domain or extracellular domain of the protein, and they activate signal transduction pathways in Ba/F3 cells that can also be activated by the normal MPL. In this paper, we report a novel spontaneously occurring mutation of MPL, with an amino acid substitution of Trp(508) to Ser(508) in the intracellular domain of MPL, that induces the factor-independent growth of Ba/F3 cells. Examination of intracellular signaling pathways demonstrated that the mutant MPL protein constitutively activates three distinct signaling pathways, SHC-Ras-Raf-MAPK/JNK, JAK-STAT, and PI3K-Akt-Bad.
Collapse
Affiliation(s)
- M Abe
- Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co Ltd, Tsukuba, Ibaraki, Japan
| | | | | | | | | |
Collapse
|
12
|
Abstract
The recent discovery of thrombopoietin has enhanced our understanding of both hematopoiesis and platelet production. Thrombopoietin supports hematopoietic stem cell survival and expansion as well as promoting all aspects of megakaryocyte development. The hormone displays many structural similarities to other members of the hematopoietic cytokine family and some notable differences, and regulation of its expression requires both receptor-mediated removal and other mechanisms. Thrombopoietin induces receptor dimerization and tyrosine phosphorylation, and a series of signaling events including activation of JAK/STAT, Shc/Ras/MAPK and PI3K/Akt; these pathways overlap with those induced by other cytokines, but the differences that lead to the unique biological effects of the hormone are gradually being uncovered. Our growing appreciation of how cytokine signaling pathways are translated into megakaryocyte development is discussed.
Collapse
Affiliation(s)
- Amy E Geddis
- Division of Hematology, University of Washington School of Medicine, Box 357710, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | | | | |
Collapse
|
13
|
Fleckenstein DS, Uphoff CC, Drexler HG, Quentmeier H. Detection of p53 gene mutations by single strand conformational polymorphism (SSCP) in human acute myeloid leukemia-derived cell lines. Leuk Res 2002; 26:207-14. [PMID: 11755471 DOI: 10.1016/s0145-2126(01)00107-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have identified new mutations in the p53 gene in 3/11 growth factor-independent and in 2/8 growth factor-dependent human acute myeloid leukemia (AML)-derived cell lines by single-strand conformational polymorphism (SSCP) and sequencing analysis. MEG-01 had a triplet deletion at codon 304; F-36P, NB-4 and MV4-11 showed point mutations at codon 344. F-36P had a second point mutation at codon 270 and NB-4 additionally at codon 319. M-MOK had a nucleotide substitution at codon 191. The frequency of p53 mutations in the cytokine-independent cell lines was comparable to that in the cytokine-dependent lines. These results suggest that loss of Wild type (wt) p53 is not the decisive event causing tumor cells to proliferate in vitro without externally added growth factors.
Collapse
MESH Headings
- Acute Disease
- Blotting, Western
- Cell Division/drug effects
- Codon/genetics
- DNA Mutational Analysis
- DNA, Neoplasm/genetics
- Genes, p53
- Granulocyte Colony-Stimulating Factor/pharmacology
- Granulocyte-Macrophage Colony-Stimulating Factor/pharmacology
- Humans
- Interleukin-3/pharmacology
- Leukemia, Myeloid/genetics
- Leukemia, Myeloid/pathology
- Point Mutation
- Polymorphism, Single-Stranded Conformational
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- RNA, Neoplasm/biosynthesis
- RNA, Neoplasm/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Deletion
- Tumor Cells, Cultured/chemistry
- Tumor Cells, Cultured/drug effects
- Tumor Suppressor Protein p53/physiology
Collapse
Affiliation(s)
- Diana S Fleckenstein
- Department of Human and Animal Cell Cultures, DSMZ-German Collection of Microorganisms and Cell Cultures, Mascheroder Weg 1 B, D-38124 Braunschweig, Germany
| | | | | | | |
Collapse
|
14
|
Broxmeyer HE, Youn BS, Kim C, Hangoc G, Cooper S, Mantel C. Chemokine regulation of hematopoiesis and the involvement of pertussis toxin-sensitive G alpha i proteins. Ann N Y Acad Sci 2001; 938:117-27; discussion 127-8. [PMID: 11458498 DOI: 10.1111/j.1749-6632.2001.tb03580.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chemokines have been implicated in regulation of various aspects of hematopoiesis, including negative regulation of the proliferation of immature subsets of myeloid progenitor cells (MPCs), chemotaxis of MPCs, and survival enhancement of MPCs after delayed growth factor addition. Since chemokine receptors are seven-transmembrane-spanning G-protein-linked receptors and the chemotactic effect in vitro of the CXC chemokine SDF-1 is pertussis toxin (PT)-sensitive, implying the involvement of G alpha i proteins as mediators of SDF-1-induced chemotaxis, we evaluated the effects of PT on other chemokine actions influencing MPCs. While the in vitro survival-enhancing effects of SDF-1 on GM-CSF and steel factor-dependent mouse bone marrow granulocyte macrophage progenitors (CFU-GM) were pertussis toxin-sensitive, the suppressive effects of the CC chemokine MIP-1 alpha and the CXC chemokine IL-8 on colony formation by GM-CSF and steel factor-sensitive CFU-GM were insensitive to pertussis toxin. These results suggest that not all chemokine-mediated effects on MPCs are necessarily mediated through pertussis toxin-sensitive G alpha i proteins.
Collapse
Affiliation(s)
- H E Broxmeyer
- Departments of Microbiology and Immunology, and Medicine (Hematology/Oncology), the Walther Oncology Center, Indiana University School of Medicine, and the Walther Cancer Institute, Indianapolis, Indiana 46202, USA.
| | | | | | | | | | | |
Collapse
|
15
|
Miyakawa Y, Rojnuckarin P, Habib T, Kaushansky K. Thrombopoietin induces phosphoinositol 3-kinase activation through SHP2, Gab, and insulin receptor substrate proteins in BAF3 cells and primary murine megakaryocytes. J Biol Chem 2001; 276:2494-502. [PMID: 11054408 DOI: 10.1074/jbc.m002633200] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thrombopoietin (TPO) is a recently characterized member of the hematopoietic growth factor family that serves as the primary regulator of megakaryocyte (MK) and platelet production. The hormone acts by binding to the Mpl receptor, the product of the cellular proto-oncogene c-mpl. Although many downstream signaling targets of TPO have been identified in cell lines, primary MKs, and platelets, the molecular mechanism(s) by which many of these molecules are activated remains uncertain. In this report we demonstrate that the TPO-induced activation of phosphoinositol 3-kinase (PI3K), a signaling intermediate vital for cellular survival and proliferation, occurs through its association with inducible signaling complexes in both BaF3 cells engineered to express Mpl (BaF3/Mpl) and in primary murine MKs. Although a direct association between PI3K and Mpl could not be demonstrated, we found that several proteins, including SHP2, Gab2, and IRS2, undergo phosphorylation and association in BaF3/Mpl cells in response to TPO stimulation, complexes that recruit and enhance the enzymatic activity of PI3K. To verify the physiological relevance of the complex, SHP2-Gab2 association was disrupted by overexpressing a dominant negative SHP2 construct. TPO-induced Akt phosphorylation was significantly decreased in transfected cells suggesting an important role of SHP2 in the complex to enhance PI3K activity. In primary murine MKs, TPO also induced phosphorylation of SHP2, its association with p85 and enhanced PI3K activity, but in contrast to the results in cell lines, neither Gab2 nor IRS2 are phosphorylated in MKs. Instead, a 100-kDa tyrosine-phosphorylated protein (pp100) co-immunoprecipitated with the regulatory subunit of PI3K. These findings support a model where PI3K activity is dependent on its recruitment into TPO-induced multiphosphoprotein complexes, implicate the existence of a scaffolding protein in primary MKs distinct from the known Gab and IRS proteins, and suggest that, in contrast to erythroid progenitor cells that employ Gab1 in PI3K signaling complexes, utilization of an alternate member of the Gab/IRS family could be responsible for specificity in TPO signaling.
Collapse
Affiliation(s)
- Y Miyakawa
- Division of Hematology, University of Washington School of Medicine, Seattle 98195, USA
| | | | | | | |
Collapse
|
16
|
Abstract
Thrombopoietin performs an essential role during hematopoiesis by regulating the expansion and maturation of megakaryocytes. In keeping with this function, megakaryocytes, platelets, and their precursors all express the thrombopoietin receptor, Mpl, on their cell surface. However, Mpl is also expressed on primitive, pluripotent hematopoietic progenitors and plays an important role in the regulation of lineages other than megakaryocytes as well as primitive progenitors. Recently, the ability of thrombopoietin to maintain and expand repopulating stem cells has been demonstrated. Thus, thrombopoietin is unique among the hematopoietic cytokines because it is necessary both for terminal maturation and regulation of lineage-specific megakaryocytes and also for maintenance of the most primitive hematopoietic stem cells. Many new strategies are evolving to exploit the activity of thrombopoietin on primitive progenitors. This may lead to faster hematopoietic recovery from marrow-suppressive therapy, effective methods of ex vivo expansion of hematopoietic stem cells, and retroviral transduction of stem cells to facilitate gene therapy.
Collapse
Affiliation(s)
- J G Drachman
- Puget Sound Blood Center, Seattle, Washington 98104, USA
| |
Collapse
|