Monocyte-endothelium-smooth muscle cell interaction in co-culture: proliferation and cytokine productions in response to advanced glycation end products

Abstract

Background: During hyperglycemia, reducing sugars react with the amino groups to form Amadori products which then form advanced glycation end-products (AGEs). Studies have shown that the AGEs and the receptor binding generated reactive oxygen species, and triggered secretion of cytokines contributing to the local regulations of proliferation and inflammation in cells. Interaction of vessel wall cells and monocytes may trigger the processes leading to atherosclerosis. We evaluated the effects of AGEs on smooth muscle cell (SMC) proliferation and cytokine synthesis in co-cultures of human monocytes (THP-1), endothelial cells (HUVEC) and aortic vascular smooth muscle cell (SMC) to clarify the effects of AGEs on vascular cells and to investigate the mechanisms of arteriosclerosis.

Methods: Glycolaldehyde-induced AGEs (glycol-AGEs) was prepared. The THP-1 and HUVEC were cultured with SMC in transwell plates with 100 μg/ml of glycol-AGEs for 24 to 48 h.

Results: The proliferation of SMC was induced by glycol-AGEs in the co-culture system. Moreover, SMC treated with glycol-AGEs also expressed interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1), and the level of cytokines expression was significantly elevated in the co-culture system of HUVEC and THP-1 when treated with glycol-AGEs.

Conclusion: These results suggest that employing a co-culture system is necessary to investigate the synergistic effects of AGEs on intercellular cellular interactions and it creates a more in vivo-like environment for AGEs implicated atherosclerosis research.

General significance: All three cell types are required to be investigated together to understand the effects of AGEs on intercellular interactions occurring among these cells.