VCAM-1 expression in adult hematopoietic and nonhematopoietic cells is controlled by tissue-inductive signals and reflects their developmental origin.
Although expression of vascular cell adhesion molecule 1 (VCAM-1) in endothelial cells and its functional implications have been previously appreciated, VCAM-1 expression in other than endothelial cells, especially hematopoietic cells, has been recently recognized and has not been explored in detail. Using normal mice and mice with a conditional ablation of VCAM-1 through a Tie2-driven cre transgene, we have studied the biodistribution and the pattern of VCAM-1 expression in circulating versus tissue-residing cells before and after their enforced mobilization. In the normal mouse, both at basal hematopoiesis or following mobilization, VCAM-1 expression is confined to myeloid cells residing in hematopoietic tissues, whereas free cells in circulation or in body cavities are devoid of VCAM-1 messenger RNA (mRNA) and protein. However, following culture, proliferating myeloid cells, but not lymphoid cells, express VCAM-1. In the VCAM-1-ablated mouse, there is an increase in circulating progenitors as a consequence of their ongoing release from bone marrow, a process enhanced by splenectomy. We postulate that the main mechanism leading to their release is the ablation of VCAM-1 by fibroblastic and by endothelial cells. Ablation of VCAM-1 in fibroblasts by Tie2-driven cre is a novel finding and likely denotes their developmental ancestry by Tie2-expressing (mesenchymal?) progenitor cells during development.
Ulyanova
Tatiana
T
Division of Hematology, University of Washington, Box 357 710, Seattle, WA 98195-7710, USA.
Scott
Linda M
LM
Priestley
Gregory V
GV
Jiang
Yi
Y
Nakamoto
Betty
B
Koni
Pandelakis A
PA
Papayannopoulou
Thalia
T
D000367:Age Factors; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology; D002478:Cells, Cultured; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D006410:Hematopoiesis / Q000502:physiology; D008214:Lymphocytes / Q000166:cytology / Q000502:physiology*; D008221:Lymphoid Tissue / Q000166:cytology / Q000502:physiology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D022423:Myeloid Cells / Q000166:cytology / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D015398:Signal Transduction / Q000502:physiology*; D013154:Spleen / Q000166:cytology / Q000502:physiology; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics* / Q000378:metabolism
D054377:Chemokine CXCL12; D019743:Chemokines, CXC; C515256:Cxcl12 protein, mouse; D012333:RNA, Messenger; D019010:Vascular Cell Adhesion Molecule-1