Proinflammatory signaling mechanism of endocan in macrophages: Involvement of TLR2 mediated MAPK-NFkB pathways

Abstract

Endocan is an endothelial cell-specific proteoglycan that contributes to vascular dysfunction by impairing endothelial function and inducing vascular smooth muscle cell migration. However, its role in regulating macrophage inflammation, a key pathological feature of vascular dysfunction, is not well understood. In this study, we investigated the effect of endocan on macrophage inflammation to better understand its contribution to vascular dysfunction. We found that endocan upregulated pro-inflammatory cytokines including IL-1β, IL-6 and TNF-α in RAW 264.7 cells and activated MAPK/NFkB signaling pathways. Inhibiting these pathways reduced endocan-induced cytokine levels, while inhibiting TLR2 compromised the MAPK/NFkB regulation. Additionally, LPS-induced HUVEC conditioned medium stimulated cytokine levels in RAW 264.7 cells, which were reduced by endocan siRNA treatment in HUVEC. These results suggest that endocan positively regulates pro-inflammation in macrophages through the TLR2-MAPK-NFkB axis, highlighting the potential of targeting endocan to reduce inflammation in vascular dysfunction.