Skip to main content
. 2020 Feb 27;11:172. doi: 10.3389/fphys.2020.00172

FIGURE 4.

FIGURE 4

IL-4 avoids the inhibitory effect of higher albumin concentration on albumin endocytosis through activation of the JAK3/STAT6 pathway. LLC-PK1 cells were grown in 24-well plates until 95% confluence was reached. Then, the cells were incubated with different compounds as indicated. (A) The effect of 20 ng/mL IL-4 on IL-4Rα chain expression (n = 6). β-actin was used as the load control. In upper panel is showed the representative images. In bottom panel is showed the densitometry analyzes. (B,C) The effect of IL-4 on the phosphorylation of STAT6 (Tyr641), STAT3 (Tyr705), PKB (Ser473), and ERK (Thr202/Tyr204). (B) Representative images of three independent experiments. (C) Densitometry analysis related to (B) (n = 3). Ptn, protein. All phosphorylated fractions of specific proteins were normalized by the total fraction of the respective proteins. (D) The effect of IL-4 on the inhibitory effect of 20 mg/mL albumin on albumin endocytosis (n = 9). Albumin endocytosis was measured by cell-associated fluorescence using albumin-FITC as a tracer. (E) The effect of 10–7 M CP-690550-10 (JAK3 inhibitor) or 10–7 M MK-2206 (PKB inhibitor) on the effect of IL-4 on albumin endocytosis (n = 6). The results are expressed as means ±SD. *P < 0.05 versus control; #P < 0.05 versus albumin; n.s., not significant.