Phenotypic heterogeneity is an evolutionarily conserved feature of the endothelium.
Mammalian endothelial cells (ECs) display marked phenotypic heterogeneity. Little is known about the evolutionary mechanisms underlying EC heterogeneity. The last common ancestor of hagfish and gnathostomes was also the last common ancestor of all extant vertebrates, which lived some time more than 500 million years ago. Features of ECs that are shared between hagfish and gnathostomes can be inferred to have already been present in this ancestral vertebrate. The goal of this study was to determine whether the hagfish endothelium displays phenotypic heterogeneity. Electron microscopy of the aorta, dermis, heart, and liver revealed ultrastructural heterogeneity of the endothelium. Immunofluorescent studies demonstrated marked differences in lectin binding between vascular beds. Intravital microscopy of the dermis revealed histamine-induced adhesion of leukocytes in capillaries and postcapillary venules, but no such adhesion in arterioles. Together, these data suggest that structural, molecular, and functional heterogeneity of the endothelium evolved as an early feature of this cell lineage.
Yano
Kiichiro
K
Center for Vascular Biology Research and Division of Molecular and Vascular Medicine, Beth Israel Deaconess Medical Center, RW-663, 330 Brookline Ave, Department of Pathology, Harvard Medical School, Boston, MA 02215, USA.
Gale
Daniel
D
Massberg
Steffen
S
Cheruvu
Pavan K
PK
Monahan-Earley
Rita
R
Morgan
Ellen S
ES
Haig
David
D
von Andrian
Ulrich H
UH
Dvorak
Ann M
AM
Aird
William C
WC
D000818:Animals; D001011:Aorta / Q000648:ultrastructure; D005075:Biological Evolution; D002196:Capillaries / Q000166:cytology; D002448:Cell Adhesion; D020405:Dermis / Q000098:blood supply / Q000648:ultrastructure; D004727:Endothelium / Q000648:ultrastructure*; D006196:Hagfishes / Q000502:physiology*; D006321:Heart / Q000033:anatomy & histology; D037102:Lectins; D007962:Leukocytes / Q000166:cytology; D008099:Liver / Q000648:ultrastructure; D010641:Phenotype; D013194:Staining and Labeling; D014699:Venules / Q000166:cytology
D037102:Lectins