Calcineurin/NFAT signalling inhibits myeloid haematopoiesis.
Bottom Line: Reconstituting lethally irradiated mice with haematopoietic stem cells expressing an NFAT-inhibitory peptide resulted in enhanced development of the myeloid compartment.Global gene expression analysis of untreated DC and NFAT-inhibited DC revealed differential expression of transcripts that regulate cell cycle and apoptosis.In conclusion, these results provide evidence that calcineurin/NFAT signalling negatively regulates myeloid lineage development.
Affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.Show MeSH
Related in: MedlinePlus
Mentions: To better understand the preference for in vivo expansion of myeloid cells, we analysed myeloid CFU obtained from reconstituted mice to determine the differentiation stage at which preferential expansion of VIVIT-expressing cells occurred. BM cells from reconstituted mice were cultured in methylcellulose media containing SCF, IL-3 and IL-6. Numbers of granulocytic and monocytic colony-forming units – granulocyte, macrophage (CFU-GM), corresponding to numbers of myeloid progenitors in BM, were determined after 4–7 days of culture (Fig 4A). Figure 4B shows numbers of CFU-GM from mice reconstituted with 30% VIVIT-eGFP competitors mixed with 70% control-tdTomato HSC and analysed 4 and 8 weeks later. Numbers of VIVIT-eGFP myeloid progenitors were significantly enriched over time compared with controls, consistent with the pattern of reconstitution achieved with NFAT-impaired myeloid cells in previous experiments (Fig 2B and C). After CFU-GM enumeration the colonies were harvested and the total number of CD11b+ cells was determined by flow cytometry. Figure 4C depicts average cell number per colony, which indicates significantly faster growth among VIVIT-eGFP expressing colonies. In mice singly engrafted with either VIVIT-eGFP or tdTomato control HSC alone, the respective progenitor populations remained detectable in BM for 12 weeks (unpublished observation).
Affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.