Fig. 6.

p38 MAPKα inhibition reduces interleukin (IL)-6 generation and signaling as a potential mechanism for beneficial effects in PH. A and B: supernatant from normoxic and hypoxic PAF ± SB203580 was analyzed using a quantitative ELISA to determine actual amounts released. Cells were growth arrested in serum free media for 24 h before hypoxic exposure. The values are mean ± SE values from triplicate wells for each sample and experiment repeated 3 times using cells from 3 animals. *P < 0.05 **P < 0.005. C: PAF were exposed to hypoxia and then RNA isolated after 48 h. The RNA was reverse transcribed into cDNA and then analyzed using quantitative (q)RT-PCR. The mRNA increased and peaked at 12 h of hypoxia. Values represent ratio of increase of IL-6 gene mRNA relative to the housekeeping gene of β-actin and calculated using comparative Ct method. Values are representative of triplicate samples from 3 experiments using 3 different animals. D: PAF were exposed to hypoxia in the presence of SB203580 and then RNA isolated after 48 h. The RNA was reverse transcribed into cDNA and then analyzed using qRT-PCR. The mRNA increased and peaked at 12 h of hypoxia. Values represent ratio of increase of IL-6 gene mRNA relative to the housekeeping gene of β-actin and calculated using comparative Ct method. Values are representative of triplicate samples from 3 experiments using 3 different animals. **P < 0.01; ***P < 0.01, for C and D. E: PAF were isolated and incubated with IL-6 (100 ng/ml) ± soluble IL-6 receptor (sIL-6) and then using DNA synthesis as a marker of cell proliferation, the response was observed. Data are mean values ± SE and are representative of duplicate experiments performed on cells from 3 different animals. *P < 0.05; **P < 0.005; ***P < 0.0001. F: PASMCs were exposed to IL-6 (100 ng/ml) ± soluble IL-6 receptor (sIL-r) and then using DNA synthesis as a marker of cell proliferation, the response was observed. Data are means ± and are representative of duplicate experiments performed on cells from 3 different animals. ****P < 0.0001. G: PASMCs were growth arrested for 24 h and then incubated with serum free media, IL-6 or IL-6 and anti-IL-6 antibody. Thymidine assay was used to quantify DNA synthesis, a measure of cell proliferation. Results are plotted as counts per million. Values are means ± SE and represent mean of 3 experiments on cells from same animal. A total of 3 different animals were used. **P < 0.01. H and I: PASMCs were stimulated with 100 ng/ml IL-6 (+) or without (−) and the protein harvested at baseline, 15 min, 30 min, 1 h, and 4 h. The cell lysates were immunoblotted for phosphorylated STAT3 and total STAT3. Experiment was repeated 3 times; blots above are representative of those experiments. H shows densitometry from repeat blots. ***P < 0.005; ****P < 0.001, for I.