Fig. 3. HSPCs can directly differentiate into M2 macrophages in response to SRT.

a CD133⁺ HSPCs were isolated from DsRed transgenic mice and transplanted intravenously into tumour bearing mice. Twenty four hours later tumours were harvested and showed that the CD133⁺DsRed HSPCs had migrated to tumours and taken up residence. Scale bar: 100 μm. b, c Representative flow plots (b) and analysis of dissociated tumours showing a decrease in CD133⁺ HSPCs and an increase in EGR2⁺ M2 macrophages with SRT (n = 6) (c). Isotype control plots are shown and depict gating strategy. Gating was established to capture changes in DsRed CD133⁺ HSPCs and DsRed EGR2⁺ M2 macrophages. Since tumours were initially transplanted with DsRed cells from transgenic mice, a DsRed population was present in isotype controls. To account for this, horizontal quadrant lines were set to differentiate between DsRed⁺ and DsRed⁻ cells present in tumours and to minimise false DsRed⁺ cells from the DsRed⁻ population. Vertical quadrant lines were set to ensure 0.1% or less of events appeared in the upper/lower right quadrants. d An image showing an EGR2⁺ cell that was derived from the originally transplanted DsRed CD133⁺ HSPCs. Scale bar: 15 μm. *p < 0.05 for indicated comparison, no animals were excluded from analysis.