Phenotypic and functional changes in blood monocytes following adherence to endothelium.

Abstract

OBJECTIVE:

Blood monocytes are known to express endothelial-like genes during co-culture with endothelium. In this study, the time-dependent change in the phenotype pattern of primary blood monocytes after adhering to endothelium is reported using a novel HLA-A2 mistyped co-culture model.

METHODS AND RESULTS:

Freshly isolated human PBMCs were co-cultured with human umbilical vein endothelial cells or human coronary arterial endothelial cells of converse human leukocyte antigen A2 (HLA-A2) status. This allows the tracking of the PBMC-derived cells by HLA-A2 expression and assessment of their phenotype pattern over time. PBMCs that adhered to the endothelium at the start of the co-culture were predominantly CD11b+ blood monocytes. After 24 to 72 hours in co-culture, the endothelium-adherent monocytes acquired endothelial-like properties including the expression of endothelial nitric oxide synthase, CD105, CD144 and vascular endothelial growth factor receptor 2. The expression of monocyte/macrophage lineage antigens CD14, CD11b and CD36 were down regulated concomitantly. The adherent monocytes did not express CD115 after 1 day of co-culture. By day 6, the monocyte-derived cells expressed vascular cell adhesion molecule 1 in response to tumour necrosis factor alpha. Up to 10% of the PBMCs adhered to the endothelium. These monocyte-derived cells contributed up to 30% of the co-cultured cell layer and this was dose-dependent on the PBMC seeding density.

CONCLUSIONS:

Human blood monocytes undergo rapid phenotype change to resemble endothelial cells after adhering to endothelium.

• Authors: Colin Tso, Kerry-Anne Rye, Philip Barter
• Journal: PloS one (PLoS One) Vol. 7 Issue 5 Pg. e37091 ( 2012) ISSN: 1932-6203 [Electronic] United States
• PMID: 22615904 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antigens, CD
• HLA-A2 Antigen
• Tumor Necrosis Factor-alpha
• Vascular Cell Adhesion Molecule-1
• Nitric Oxide Synthase Type III
• Vascular Endothelial Growth Factor Receptor-2

Topics

• Antigens, CD (metabolism)
• Cell Adhesion (physiology)
• Cells, Cultured
• Coculture Techniques (methods)
• Down-Regulation
• Endothelium, Vascular (cytology, metabolism, physiology)
• HLA-A2 Antigen (metabolism)
• Human Umbilical Vein Endothelial Cells (cytology, metabolism, physiology)
• Humans
• Leukocytes, Mononuclear (cytology, metabolism, physiology)
• Macrophages (metabolism, physiology)
• Monocytes (cytology, metabolism, physiology)
• Nitric Oxide Synthase Type III (metabolism)
• Phenotype
• Tumor Necrosis Factor-alpha (metabolism)
• Vascular Cell Adhesion Molecule-1 (metabolism)
• Vascular Endothelial Growth Factor Receptor-2 (metabolism)