Arginine methyltransferase PRMT5 is essential for sustaining normal adult hematopoiesis
Fan Liu, … , Luisa Luciani, Stephen D. Nimer
Fan Liu, … , Luisa Luciani, Stephen D. Nimer
Published August 10, 2015
Citation Information: J Clin Invest. 2015;125(9):3532-3544. https://doi.org/10.1172/JCI81749.
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Arginine methyltransferase PRMT5 is essential for sustaining normal adult hematopoiesis

Abstract

Epigenetic regulators play critical roles in normal hematopoiesis, and the activity of these enzymes is frequently altered in hematopoietic cancers. The major type II protein arginine methyltransferase PRMT5 catalyzes the formation of symmetric dimethyl arginine and has been implicated in various cellular processes, including pluripotency and tumorigenesis. Here, we generated Prmt5 conditional KO mice to evaluate the contribution of PRMT5 to adult hematopoiesis. Loss of PRMT5 triggered an initial but transient expansion of hematopoietic stem cells (HSCs); however, Prmt5 deletion resulted in a concurrent loss of hematopoietic progenitor cells (HPCs), leading to fatal BM aplasia. PRMT5-specific effects on hematopoiesis were cell intrinsic and depended on PRMT5 methyltransferase activity. We found that PRMT5-deficient hematopoietic stem and progenitor cells exhibited severely impaired cytokine signaling as well as upregulation of p53 and expression of its downstream targets. Together, our results demonstrate that PRMT5 plays distinct roles in the behavior of HSCs compared with HPCs and is essential for the maintenance of adult hematopoietic cells.

Authors

Fan Liu, Guoyan Cheng, Pierre-Jacques Hamard, Sarah Greenblatt, Lan Wang, Na Man, Fabiana Perna, Haiming Xu, Madhavi Tadi, Luisa Luciani, Stephen D. Nimer

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Figure 5

PRMT5 loss has distinct effects on the cell cycle regulation of hematopoietic stem versus progenitor cells.

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PRMT5 loss has distinct effects on the cell cycle regulation of hematopo...
(A) Protein lysates of BM cells isolated on day 7 from control and PRMT5-deleted mice were resolved on SDS-PAGE gels and probed with antibodies recognizing PRMT5, caspase 3, and β-actin. Lysates prepared from BM cells isolated from LPS-treated mice were used as a positive control (Pos). Arrow indicates the cleaved caspase 3. (B) FACS analysis of annexin V in day-7 Lin+, LK, and LSK cells. Percentages of annexin V+ cells are plotted (n = 4). (C) FACS analysis of in vivo BrdU incorporation assays using BM cells isolated from day-7 control, Prmt5 heterozygous, and Prmt5 homozygous KO mice. Cells were first gated on LK or LSK cells; the frequency of BrdU+ cells is indicated on the plots. (D) The percentage of BrdU+ S-phase cells is shown for the Lin+, LK, and LSK cells isolated from day-7 control and Prmt5 homozygous KO mice (n = 6). (E and F) Representative FACS analysis of Ki67 expression in LT-HSCs. BM cells isolated from day-7 control and Prmt5-deleted mice were gated on CD34– and FLT3– LSK (E) or CD48– and CD150+ LSK (F) cells; the frequency of Ki67+ cells is indicated on the plot. (G) The percentage of Ki67+ LT-HSCs in BM cells from Prmt5fl/fl and Prmt5Δ/Δ mice is plotted (n = 5). All P values were determined by 2-tailed Student’s t test.