Figure 5.

ERK1/2 (extracellular-signal regulated kinases 1/2) phosphorylation and OPN (osteopontin) expression. A, Quantification of ERK1/2 phosphorylation and representative western blots in sinus rhythm (SR) tissue samples compared with atrial fibrillation (AF; SR [n=6], AF [n=7]; results are given as mean±SEM, P value was determined by a Welch test). B, Quantification and representative western blots for ERK1/2 phosphorylation in PLK WT and knockout (KO) primary cardiac fibroblasts (WT [n=4], KO [n=4]; results are given as mean±SEM determined by a Mann-Whitney U test). C, Quantification and representative western blots for ERK1/2 phosphorylation in human atrial fibroblast (HAF)-SRK01 fibroblasts upon PLK2 inhibition with 50 and 100 nmol/L of the specific PLK2 inhibitor TC-S 7005 (control [n=3], 50 nmol/L [n=3], 100 nmol/L [n=3]; results are given as mean±SEM, P value was determined by a Kruskal-Wallis test with Dunn multiple comparison test). D, Quantification of OPN protein abundance and representative western blots in primary cardiac PLK2 WT and KO fibroblasts. The specific ERK1/2 inhibitor SCH772984 was used at 10 nmol/L for 72 h (WT [n=9], 50 KO [n=9], KO+ERKi [n=4]; results are given as mean±SEM, P value was determined by a Kruskal-Wallis test with Dunn multiple comparisons test). AU indicates arbitrary unit—relative protein expression normalized to the indicated housekeeping protein and the respective control group.