A. Centriole splitting, where centrin dots co-stained with NEDD1 are dispersed throughout the cytoplasm, occurs in vHMECs. At least 8 centrin/NEDD1 co-stained marks are observed in this cell, which consist of four centrin/NEDD1 singlets and two centrin/NEDD1 doublets. At the bottom of the image, insets show individual centrin, NEDD1 and merged image. Bar, 5 μm. B. Amplification of centrin—more than four spots—increases with PDs in both mononucleated and binucleated vHMECs. Error bars, standard error of the mean; n = 2, *P < 0.05 X2-test (early PD vs. late PD). C. Representative images of amplification of centrioles. On the first row, mononucleated vHMECs with > 4 centrin signals in combination with: 2 NEDD1 signals (left side), 4 NEDD1 signals (center) and > 4 NEDD1 signals (right side). On the second row, binucleated vHMECs with > 4 centrin signals in combination with: 4 NEDD1 (left side) or > 4 NEDD1 signals (right side). At the bottom of each image, insets show individual centrin and NEDD1 signals and the merged image. Bar, 5 μm.