Vascular smooth muscle cell phenotype is modulated by ligands of the lymphotoxin β receptor and the tumor necrosis factor receptor

Abstract

ObjectiveVascular smooth muscle cells (VSMCs) undergo a phenotypic-switching process during the generation of unstable atheroma plaques. In this investigation, the potential implication of the tumor necrosis factor superfamily (TNFSF) ligands, in the gene expression signature associated with VSMC plasticity was studied. Material and methodsHuman aortic (ha)VSMCs were obtained commercially and treated with the cytokine TNFSF14, also called LIGHT, the lymphotoxin alpha (LTα), the heterotrimer LTα1β2 or with vehicle for 72h. The effect of the different treatments on gene expression was analyzed by quantitative PCR and included the study of genes associated with myofibroblast-like cell function, osteochondrogenesis, pluripotency, lymphorganogenesis and macrophage-like cell function. ResultsHaVSMCs displayed a change in myofibroblast-like cell genes which consisted in reduced COL1A1 and TGFB1 mRNA levels when treated with LTα or LIGHT and with augmented MMP9 expression levels when treated with LTα. LTα and LIGHT treatments also diminished the expression of genes associated with osteochondrogenesis and pluripotency SOX9, CKIT, and KLF4. By contrary, all the above genes were no affected by the treatment with the trimer LTα1β2. In addition, haVSMC treatment with LTα, LTα1β2 and LIGHT altered lymphorganogenic cytokine gene expression which consisted of augmented CCL20 and CCL21 mRNA levels by LTα and a reduction in the gene expression of CCL21 and CXCL13 by LIGHT and LTα1β2 respectively. Neither, LTα or LIGHT or LTα1β2 treatments affected the expression of macrophage-like cell markers in haVSMC. ConclusionsAltogether, indicates that the TNFSF ligands through their interconnected network of signaling, are important in the preservation of VSMC identity against the acquisition of a genetic expression signature compatible with functional cellular plasticity.