Fig 2: STAT3 signaling activation is regulated by JMJD1C and stimulates PASMC proliferation and glycolysis.A Protein levels of p-STAT3 and STAT3 in PASMCs were determined by Western blotting. B The CCK8 assay was used to examine the survival of PASMCs. C Representative immunofluorescence images of PASMCs stained with anti-Ki67 antibodies (red). Cell nuclei were stained with DAPI (blue). Bar = 50 μm. D Western blotting was performed to detect the protein levels of HK2, PGK1, and LDHA in PASMCs. Nor Normoxia, Hx Hypoxia. The values are the mean ± SD, and statistical significance was determined by one-way ANOVA. N = 3, **p < 0.01.

Fig 3: JMJD1C knockdown decreases PASMC hyperproliferation and resistance to apoptosis in mice exposed to hypoxia.A, B The mRNA and protein levels of JMJD1C in lungs were detected using qPCR and Western blotting. C Representative lung sections were subjected to immunofluorescence staining of α-SMA (green) and JMJD1C (red) (left panel). DAPI was used to stain cell nuclei (blue). Arrows indicate the coexpression of α-SMA and JMJD1C in pulmonary arteries. The percentage of JMJD1C+ cells in pulmonary arteries (stained with α-SMA) was quantified (right panel). Bar = 50 μm. D Representative immunofluorescence images of lung sections stained with anti-α-SMA antibodies (green) and anti-Ki67 antibodies (red) (left panel). DAPI was used to stain cell nuclei (blue). Arrows indicate the colocalization of α-SMA and Ki67 in pulmonary arteries. The percentage of Ki67+ cells in pulmonary arteries (stained with α-SMA) was quantified (right panel). Bar = 50 μm. E Representative immunofluorescence images of lung sections stained with anti-α-SMA antibodies (green) and TUNEL (red) (left panel). DAPI was used to stain cell nuclei (blue). Arrows indicate the colocalization of α-SMA and TUNEL in pulmonary arteries. The percentage of TUNEL+ cells in pulmonary arteries (stained with α-SMA) was quantified (right panel). Bar = 50 μm. Nor Normoxia, Hx Hypoxia. The values are the mean ± SD, and statistical significance was determined by one-way ANOVA. N = 6, *p < 0.05, **p < 0.01.

Fig 4: JMJD1C knockdown attenuates pathological changes in mice exposed to hypoxia.A Illustration of the animal protocols. B, C The RVSP and RVHI in mice exposed to normoxia or hypoxia were examined. D Representative histological images of heart sections stained with H&E. Bar = 50 μm. E Representative histological images of lung sections stained with H&E. The wall thickness of the pulmonary arteries was measured. Bar = 100 μm. Nor Normoxia, Hx Hypoxia, L Lumen. The values are the mean ± SD, and statistical significance was determined by one-way ANOVA. N = 6, *p < 0.05, **p < 0.01.

Fig 5: JMJD1C expression is increased in the lungs of mice exposed to hypoxia.A, B Expression levels of JMJD1C mRNA in lung homogenates of PAH patients in GSE113439 and GSE53408. N = 11–15. C, D Relative mRNA and protein levels of JMJD1C in the lung were examined by qPCR and Western blotting. E Representative lung tissue sections were subjected to immunofluorescence staining of α-SMA (green) and JMJD1C (red). DAPI was used to stain cell nuclei (blue). Bar = 50 μm. Arrows indicate the coexpression of α-SMA and JMJD1C in pulmonary arteries. F, G The RVSP, and RVHI were determined in mice exposed to normoxia or hypoxia. H Representative histological images of lung sections stained with hematoxylin and eosin (H&E). The wall thickness of the pulmonary arteries was measured. Bar = 100 μm. Nor normoxia; Hx hypoxia; L Lumen. The values are the mean ± SD, and statistical significance was assessed by unpaired t-test. N = 6, **p < 0.01.