Fig. 2: TGFβ and JAK2/STAT3 signaling in bone marrow mesenchymal stromal cells from MPN patients.

Paraffin-embedded bone marrow samples from healthy donors (HDs) and patients with polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). a Immunocytochemistry assay for transforming growth factor beta (TGFβ; shown in brown). Nuclei were counterstained with hematoxylin (purple). Scale bar 50 µm. b Quantification of immunocytochemistry results, representing the percentage of TGFβ-positive cells. c Bone marrow mesenchymal stromal cells (BM-MSCs) from HDs and patients with PV, ET, and PMF. Western blot indicating the protein expression of TGFβ receptor 1 (TGFBR1), phosphorylated mothers against decapentaplegic homolog 3 (pSMAD3), and total SMAD3. d Quantification of the TGFBR1 and pSMAD3 Western blot bands. e Western blot indicating the protein expression of phosphorylated signal transducer and activator of transcription 3 (pSTAT3) and total STAT3. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was used as a loading control. f Quantification of the pSTAT3 and STAT3 Western blot bands. g HD BM-MSCs treated with the indicated concentrations of TGFβ for 30 min. Western blot indicating the protein expression of STAT3, pSTAT3, SMAD3, and pSMAD3. GAPDH was used as a loading control. h Quantification of the STAT3 and SMAD3 Western blot bands. n = 4; b, d, f, and h mean + SEM, *p < 0.05, **p < 0.01, ***p < 0.001.