Figure 5. Loss of CD47 is associated with up-regulation of stem cell transcription factors in vivo.

(A) Relative c-Myc mRNA expression in lung, kidney, liver, brain and spleen of CD47-null versus WT mice. (B) c-Myc mRNA levels in purified splenic cell populations from WT and CD47 null mice. (C) mRNA expression levels in lung from WT and CD47-null mice. (D) mRNA expression levels in spleen from WT and CD47-null mice. (*p < 0.05, **p < 0.01). (E–H) Increased frequency of Sox2 expressing cells in tissues from CD47-null mice. The alveolar (Alv) regions of lung tissues from WT (E) generally lack Sox2-positive cells (brown stain), whereas CD47-null lung shows more positive cells (F). In contrast, similar uniform Sox2 staining was observed in bronchiolar epithelium (BrEp) from WT and null mice, consistent with its previously reported expression in Clara cells⁴⁵. (G–H) Paraffin embedded sections of representative spleen tissues from WT (G) and CD47−/− (H) mice were stained with a specific antibody to Sox2. Sections were examined under light microscopy showing subcapsular (CP), red pulp (RP) and white pulp (WP) staining.