Abstract

The accumulation of vascular smooth muscle (SM)-like cells within the intima contributes significantly to intimal medial thickening (IMT) and vascular remodelling typical of arteriosclerotic disease. The source of these cells remains controversial. Light has emerged as a powerful tool to interrogate cells label-free and facilitates discriminant observations both in vitro and in vivo. The auto-fluorescence (AF) profile of individual cells isolated from arteriosclerotic vessels, captured on V-cup array and interrogated across five wavelengths using a novel Lab-on-a-Disc platform, was significantly increased at the 565±20 nm wavelength concomitant with a reduction in Myh11 expression, when compared to differentiated vascular smooth muscle cells (SMC) from control vessels. In vitro, TGF-β1 promoted myogenic differentiation of murine bone-marrow derived Sca1⁺/CD44⁺mesenchymal stem cells (MSC) and murine Sca1⁺ C3H 10 T1/2 cells concomitant with enrichment of the specific SMC epigenetic histone mark, H3K4me2 at the Myh11 promoter, Myh11 promoter transactivation and increased SMC differentiation marker mRNA and protein expression. Myogenic differentiation resulted in a significant increase in the AF intensity across 565±20 nm wavelength, an effect not observed for TGF-β1 treated RAMOS human B lymphocytes but mimicked by Notch activation of resident Sca1⁺multipotent vascular stem cells (MVSCs) with Jagged1 and inhibited following elastin and collagen III depletion, respectively. Moreover, the temporal increase in the AF intensity at 565±20 nm wavelength during myogenic differentiation was similar to the AF profile of dissociated cells from arteriosclerotic vessels at this same wavelength. These data suggest that an AF photonic fingerprint of stem cell-derived myogenic progeny in vitro mimics that of vascular cells ex vivo. following IMT.