Figure 4.
PLK2 (polo-like kinase 2)-dependent osteopontin expression. A, OPN (osteopontin) protein abundance in PLK2 WT and knockout (KO) primary fibroblast cell culture medium determined by mass spectrometry (WT [n=3], KO [n=3]; results are given as mean±SEM, P value was determined by the Benjamini Hockberg method after Bayesian statistics [see Methods]). B, Quantification and representative western blot for OPN 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 posttest). C, Quantification and representative western blot for OPN in sinus rhythm (SR) and atrial fibrillation (AF) right atrial tissue (SR [n=10], AF [n=11]; results are given as mean±SEM, P value was determined by an unpaired, 2-tailed t test). D, ELISA measurement of OPN concentration in the peripheral blood (PB) of healthy control patients in patients with SR and AF with or without electrophysiologically determined low-voltage zones (LVZs) as fibrosis surrogates (SR [n=4], AFLVZ absent [n=8], AFLVZ present [n=9]; results are given as mean±SEM, P value was determined by a Kruskal-Wallis test with Dunn posttest). E, Quantification and representative western blot for αSMA (alpha smooth muscle actin) in HAF-SRK01 fibroblasts treated with 25 ng/mL OPN for 72 h (control [n=4], OPN [n=4]; results are given as mean±SEM, P value was determined by a Mann-Whitney U test). F, Quantification and original western blot for OPN protein abundance in HAF-SRK01 fibroblasts after 24 and 96 h hypoxia treatment (control [n=4], 24 h hypoxia [n=5], 96 h hypoxia [n=5]; 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.