Coculture with Late, but Not Early, Human Endothelial Progenitor Cells Up Regulates IL-1βExpression in THP-1 Monocytic Cells in a Paracrine Manner

[摘要] Endothelial progenitor cells (EPCs) have been used in clinical trials to treat ischemic heart disease. Monocyte infiltration plays an important role in inflammation, angiogenesis, and tissue repair during tissue ischemia. It is important to understand the interactions between EPCs and monocytes. In this study, a human EPC/THP-1 monocytic cell coculture system was used to examine EPC effect on IL-1α, IL-1β, and TNF-αexpression in THP-1 cells. Late, but not early, EPCs upregulated IL-1βexpression at both mRNA and protein levels. In contrast, neither early nor late EPCs affected IL-1αor TNF-αexpression. Coculture with human umbilical vein endothelial cells did not alter IL-1βexpression. It has been shown that activation of integrinβ2 in human neutrophils augments IL-1βsynthesis; however integrinβ2 was not involved in IL-1βexpression in THP-1 cells. Addition of late EPC conditioned medium to THP-1 cell culture led to a modest increase of IL-1βmRNA levels, indicating that late EPCs upregulate IL-1βexpression partly through a paracrine pathway. IL-1β, an important inflammation mediator, has been shown to promote EPC function. Our data therefore suggest that late EPCs can exert self-enhancement effects by interacting with monocytes and that EPCs might modulate inflammatory reactions by regulating IL-1βexpression in monocytes.

[学科分类] 生物技术