Fig. 4

STAT3 phosphorylation is required for IL-21, IL-22, and IL-23 cytokines anti-apoptotic effect on structural cells. Primary human lung fibroblasts were stimulated or not with cytokines in the presence or absence of AS601245 inhibitor and then exposed to dexamethasone 5 μM for 24 h. The percentage of apoptotic cells were quantified by flow cytometry using Annexin V-PE and PI. Apoptotic cells were categorised as being Annexin V+ve but PI-ve. a Representative FACS data showing level of apoptosis in dexamethasone treated fibroblasts following IL-21+22+23 cytokines stimulation in the presence or absence of p-STAT3 inhibitor. b Level of apoptosis in dexamethasone treated fibroblasts following IL-22, 22, and 23 cytokines stimulation, alone or in combinations, in the presence or absence of p-STAT3 inhibitor (n = 7). Data is expressed as means ± SE. Apoptosis of cells treated only with dexamethasone were compared to non-treated cells. Apoptosis of cells treated with Dexamethasone and cytokines were compared to cells treated only with Dexamethasone (* p ≤0.05). Apoptosis of cells treated with Dexamethasone and cytokines were compared in the presence or absence of p-STAT3 inhibitor (**p ≤0.05)