| 1. |
- Au, A. E., et al.
(author)
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Altered B-lymphopoiesis in mice with deregulated thrombopoietin signaling
- 2017
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7:1
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Journal article (peer-reviewed)abstract
- Thrombopoietin (TPO) is the master cytokine regulator of megakaryopoiesis. In addition to regulation of megakaryocyte and platelet number, TPO is important for maintaining proper hematopoietic stem cell (HSC) function. It was previously shown that a number of lymphoid genes were upregulated in HSCs from Tpo(-/-)mice. We investigated if absent or enhanced TPO signaling would influence normal B-lymphopoiesis. Absent TPO signaling in Mpl(-/-)mice led to enrichment of a common lymphoid progenitor (CLP) signature in multipotential lineage-negative Sca-1(+)c-Kit(+) (LSK) cells and an increase in CLP formation. Moreover, Mpl(-/-)mice exhibited increased numbers of PreB2 and immature B-cells in bone marrow and spleen, with an increased proportion of B-lymphoid cells in the G1 phase of the cell cycle. Conversely, elevated TPO signaling in Tpo(Tg) mice was associated with reduced B-lymphopoiesis. Although at steady state, peripheral blood lymphocyte counts were normal in both models, Mpl(-/-)E mu-myc mice showed an enhanced preneoplastic phase with increased numbers of splenic PreB2 and immature B-cells, a reduced quiescent fraction, and augmented blood lymphocyte counts. Thus, although Mpl is not expressed on lymphoid cells, TPO signaling may indirectly influence B-lymphopoiesis and the preneoplastic state in Myc-driven B-cell lymphomagenesis by lineage priming in multipotential progenitor cells.
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| 2. |
- Au, A. E., et al.
(author)
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Proinflammatory microenvironment promotes lymphoma progression in mice with high megakaryocyte and TPO levels
- 2023
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In: Blood Advances. - : American Society of Hematology. - 2473-9529 .- 2473-9537. ; 7:8, s. 1560-1571
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Journal article (peer-reviewed)abstract
- Platelets have been shown to enhance the survival of lymphoma cell lines, but it is unclear if they play a role in lymphoma. Here we investigate a potential role for platelets and/or megakaryocytes in Eµ-myc lymphoma progression. Eµ-myc tumour cells were transplanted into recipient wild-type control mice, Mpl-/-, or TpoTg mice, which exhibit normal, low and high platelet and megakaryocyte counts, respectively. Transplanted TpoTg mice exhibited enhanced lymphoma progression with increased WBC counts, spleen and lymph node weights and enhanced liver infiltration when compared to wild-type. Conversely, tumour bearing Mpl-/- mice presented with reduced WBC counts, lymph node weights and less liver infiltration when compared to wild-type. Utilizing a Mpl-deficient thrombocytopenic immunocompromised mouse model, our results were confirmed with the human NHL GRANTA cell line. While we found that platelets and platelet released molecules supported Eµ-myc tumour cell survival in vitro, pharmacological inhibition of platelet function or anticoagulation in Eµ-myc transplanted wild-type mice did not improve disease outcome. Furthermore, transient platelet depletion or sustained Bcl-xL dependent thrombocytopenia did not alter lymphoma progression. Cytokine analysis of the bone marrow fluid microenvironment revealed increased levels of the proinflammatory molecule interleukin (IL)-1 in TpoTg mice, whereas levels were lowered in Mpl-/- mice. Moreover, RNA sequencing of blood-resident Eµ-myclymphoma cells from TpoTgand wild-type mice after tumour transplant revealed upregulation of hallmark gene sets associated with inflammatory response in TpoTg mice. We propose that a pro-inflammatory microenvironment in TpoTgmice promoted lymphoma progression.
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