Fig. 2: Clonal hematopoiesis with JAK2V617F exacerbates pulmonary hypertension and infiltration of perivascular neutrophils in bone marrow transplanted recipients with wild-type lungs in response to chronic hypoxia.

a Schematic diagram of the experimental design. Bone marrow (BM) cells from WT or JAK2^V617F mice were injected into lethally irradiated recipient WT mice with the same C57BL/6 J background. Five weeks after BM transplantation (BMT), the recipient mice transplanted with JAK2^V617F BM cells (JAK2^V617F-BMT) or WT BM cells (WT-BMT) were exposed to normoxia or hypoxia for 3 weeks. b Jak2V617F allele frequencies (%) in peripheral blood of each JAK2^V617F-BMT mouse at 4 and 8 weeks after BMT at normoxia (blue circles, n = 8) or chronic hypoxia exposure (red circles, n = 8). Statistical comparison was performed by the paired Student’s t test (two-sided). c Peripheral blood cell counts in WT-BMT or JAK2^V617F-BMT mice after exposure to normoxia or hypoxia (n = 9, 10, 10, 9, ^*P = 0.0121, ^†P = 0.0388 for WBC, n = 9, 11, 10, 11, ^*P < 0.0001 [left], <0.0001 [right] for Hb, n = 9, 11, 10, 10 for PLT). d RVSP and RV hypertrophy determined by RV/LV + S in WT-BMT or JAK2^V617F-BMT mice after exposure to normoxia or hypoxia (n = 7, 11, 10, 9, ^*P = 0.0002 [left], < 0.0001 [right], ^†P = 0.0054 for RVSP, n = 10, 11, 10, 11, ^*P < 0.0001 [left], <0.0001 [right], ^†P < 0.0001 for RV/LV + S). e Representative images of EM-stained sections and sections immunostained with anti-αSMA antibody from WT-BMT and JAK2^V617F-BMT mice. Scale bars, 25 µm. f Quantitative analysis of medial wall thickness in EM-stained sections (left, n = 6, 6, 8, 8, ^*P = 0.0465 [left], <0.0001 [right], ^†P = 0.0346) and the percentage of muscularized distal pulmonary vessels in αSMA-immunostained sections (right, n = 6 in each group, ^*P = 0.0001 [left], <0.0001 [right], ^†P = 0.0016). g Representative immunofluorescence images of lung sections stained with anti-Ly6G (green) antibody and DAPI (blue). Scale bars, 50 μm. h Quantitative analysis of Ly6G-positive cells in the perivascular regions (n = 3 in each group, ^*P < 0.0001, ^†P = 0.0387 [left], <0.0001 [right]). i Elastase activity in the lungs from WT -BMT and JAK2^V617F-BMT mice. The average value of normoxia-exposed WT-BMT mice was set to 1 (n = 3 in each group, ^†P = 0.0128). j Relative mRNA expression levels of Ccl2, Cxcl1, Ccr1, and Cxcr2 in the lungs. The 18 s rRNA was used for normalization. The average value from the normoxia-exposed WT-BMT mice was set to 1 (n = 6, 6, 8, 8, ^*P = 0.0171, ^†P = 0.0159 for Ccl2, n = 5, 6, 5, 5 ^*P = 0.0004, ^†P = 0.0065 for Cxcl1, 6, 6, 8, 8, ^*P = 0.0171, ^†P = 0.0040 for Ccr1, n = 6, 6, 5, 5, ^†P = 0.0056 for Cxcr2). The data are presented as mean ± SEM. ^*P < 0.05 versus the corresponding normoxia-group and ^†P < 0.05 versus the corresponding WT-BMT mice by the one-way ANOVA with Tukey post-hoc analysis. WT-BMT, recipient WT mice transplanted with BM cells of WT mice; JAK2^V617F-BMT, recipient WT mice transplanted with BM cells of JAK2^V617F mice. WBC white blood cell count, Hb hemoglobin concentration, PLT platelet count. Source data are provided as a Source Data file.