Wnt2 and WISP-1/CCN4 Induce Intimal Thickening via Promotion of Smooth Muscle Cell Migration

Objective: Increased vascular smooth muscle cell (VSMC) migration leads to intimal thickening in coronary artery restenosis and vein graft failure as well as acting as a soil for atherosclerosis. Investigating factors involved in VSMC migration may enable us to reduce intimal thickening and improve patient outcomes. In this study we determined whether Wnt proteins regulate VSMC migration and thereby intimal thickening.

Approach and Results: Wnt2 mRNA and protein expression were specifically
increased in migrating mouse aortic VSMCs. Moreover, VSMC migration was induced by recombinant Wnt2 (rWnt2) in vitro. Addition of rWnt2 protein increased Wnt1- inducible-signalling pathway protein-1 (WISP-1) mRNA by ~1.7-fold, via - catenin/TCF signalling, while siRNA knockdown of Wnt-2 reduced WISP-1 mRNA by ~65%. Treatment with rWISP-1, significantly increased VSMC migration by ~1.5-fold, while WISP-1 siRNA knockdown reduced migration by ~40%. Wnt2 and WISP-1 effects were integrin-dependent and not additive, indicating that Wnt2 promoted VSMC migration via WISP-1. Additionally, Wnt2 and WISP-1 were significantly increased and co-located in human coronary arteries with intimal thickening. Reduced Wnt2 and WISP-1 levels in mouse carotid arteries from Wnt2+/- and WISP-1 -/- mice, respectively, significantly suppressed intimal thickening in response to carotid artery ligation. In contrast, elevation of plasma WISP-1 via an adenovirus encoding WISP-1 significantly increased intimal thickening by ~1.5-fold compared to mice receiving control virus.

Conclusions: Upregulation of Wnt2 expression enhanced WISP-1 and promoted
VSMC migration and thereby intimal thickening. As novel regulators of VSMC
migration and intimal thickening, Wnt2 or WISP-1 may provide a potential therapy for restenosis and vein graft failure.