Verification of endothelial cell identity with a CD31/PECAM marker for human adult endothelial cells

Student: Sarah Sanchez Hurtado

Faculty Mentor: Lisa Hua

Biology

College of Science, Technology, and Business

Homologous chromosomes spatially segregate across the axis defined by the two centromeres in a dividing human cell, a process called antipairing. Antipairing has been reported for neonatal human umbilical vein endothelial cells (HUVECs), a potential mechanism for preventing somatic homologous pairing and recombination. Mitotic recombination can lead to genetic instability, including the loss of heterozygosity, which could be detrimental to the cell. It is unknown whether this antipairing organization observed in neonatal endothelial cells is maintained throughout adulthood. Preliminary findings from our lab indicate a loss of antipairing in human adult aortic endothelial cells (HAECs), suggesting antipairing organization may be disrupted in adult endothelial cells. However, it remains uncertain whether the endothelial cell phenotype is preserved in these adult cells. To test whether the adult HAECs preserve their endothelial identity, we completed immunofluorescence staining for an endothelial cell junction marker, CD31/PECAM-1. CD31/PECAM-1 is a cell-to-cell anchoring junction marker that maintains endothelial cell junctional integrity and localizes to the cell's outer membrane. Neonatal HUVECs were used as our positive control, and retinal pigment epithelial-1 (RPE-1) cells, an epithelial cell line, served as our negative control. Our data show CD31/PECAM-1 localization to the outer membrane of HUVECs and HAECs, with no such localization in RPE-1 cells. This data suggests the adult HAECs have preserved their endothelial identity, whereas the absence of marker staining would have implied the loss of identity. Findings from our study provide new insight into chromosome organization and its loss of fidelity in aged endothelial cells.