NON-ENZYMATIC GLYCATION INTERFERES WITH FIBRONECTIN-INTEGRIN INTERACTIONS IN VASCULAR SMOOTH MUSCLE CELLS

Abstract

Objective

We aimed to investigate whether advanced non-enzymatic glycation of the extracellular matrix (ECM) protein, fibronectin, impacts its normal integrin-mediated interaction with arteriolar vascular smooth muscle cells (VSMC).

Methods

Atomic force microscopy (AFM) was performed on cultured VSMC from rat cremaster arterioles to study native and glycated fibronectin (FN and gFN) interactions with cellular integrins. AFM probes were functionalized with FN or gFN or with native or glycated albumin (gAlb) as controls.

Results

VSMC showed increased adhesion probability to gFN (72.9 ± 3.5 %) compared to native FN (63.0 ± 1.6 %). VSMCs similarly showed increased probability of adhesion (63.8 ± 1.7 %) to gAlb compared to native Alb (40.1 ± 4.7 %). Adhesion of native FN to VSMC was α5 and β1 integrin-dependent whereas adhesion of gFN to VSMC was integrin-independent. The RAGE-selective inhibitor, FPS-ZM1, blocked gFN (and gAlb) adhesion suggesting that adhesion of glycated proteins was RAGE-dependent. Interaction of FN with VSMC was not altered by soluble gFN while soluble native FN did not inhibit adhesion of gFN to VSMC. In contrast, gAlb inhibited adhesion of gFN to VSMC in a concentration-dependent manner.

Conclusions

Glycation of FN shifts the nature of cellular adhesion from integrin- to RAGE-dependent mechanisms.