Di-n-butyl phthalate promotes monocyte recruitment via miR-137-3p-SP1-MCP-1 pathway

In vitro and in vivo exposure of endothelial cells to dibutyl phthalate promotes monocyte adhesion

The effect of endothelial cells' exposure to dibutyl phthalate (DBP) on monocyte adhesion is largely unknown. We evaluated monocyte adhesion to DBP-exposed endothelial cells by combining three approaches: short-term exposure (24 h) of EA.hy926 cells to 10-6, 10-5, and 10-4 M DBP, long-term exposure (12 weeks) of EA.hy926 cells to 10-9, 10-8, and 10-7 M DBP, and exposure of rats (28 and 90 days) to 100, 500, and 5000 mg DBP/kg food. Monocyte adhesion to human EA.hy926 and rat aortic endothelial cells, expression of selected cellular adhesion molecules and chemokines, and the involvement of extracellular signal-regulated kinase 1/2 (ERK1/2) were analyzed. We observed increased monocyte adhesion to DBP-exposed EA.hy926 cells in vitro and to rat aortic endothelium ex vivo. ERK1/2 inhibitor prevented monocyte adhesion to DBP-exposed EA.hy926 cells in short-term exposure experiments. Increased ERK1/2 phosphorylation in rat aortic endothelium and transient decrease in ERK1/2 activation following long-term exposure of EA.hy926 cells to DBP were also observed. In summary, exposure of endothelial cells to DBP promotes monocyte adhesion, thus suggesting a possible role for this phthalate in the development of atherosclerosis. ERK1/2 signaling could be the mediator of monocyte adhesion to DBP-exposed endothelial cells, but only after short-term high-level exposure.

Stress, Vascular Smooth Muscle Cell Phenotype and Atherosclerosis: Novel Insight into Smooth Muscle Cell Phenotypic Transition in Atherosclerosis

PURPOSE OF REVIEW

Our work is to establish more distinct association between specific stress and vascular smooth muscle cells (VSMCs) phenotypes to alleviate atherosclerotic plaque burden and delay atherosclerosis (AS) progression.

RECENT FINDING

In recent years, VSMCs phenotypic transition has received significant interests. Different stresses were found to be associated with VSMCs phenotypic transition. However, the explicit correlation between VSMCs phenotype and specific stress has not been elucidated clearly yet. We discover that VSMCs phenotypic transition, which is widely involved in the progression of AS, is associated with specific stress. We discuss approaches targeting stresses to intervene VSMCs phenotypic transition, which may contribute to develop innovative therapies for AS.

Di-n-butyl phthalate regulates vascular smooth muscle cells phenotypic switching by MiR-139-5p-MYOCD pathways

Di-n-butyl phthalate (DBP) is ubiquitous in environment and has been detected in almost all human bodies. Few data could be found about the effects of DBP on cardiovascular system, though its reproductive toxicities have been studied extensively. This study aimed to explore effects of DBP on phenotypic switching of vascular smooth muscle cells (VSMCs), an essential step during the formation of atherosclerosis (AS). A7r5 cells were employed and exposed to various levels of DBP (10^-9, 10^-8, 10^-7, 10^-6, and 10^-5 M) or DMSO as control. CCK-8 assay was used to detect the effects of DBP on cell viability. Expressions of mRNA/miRNAs and proteins were measured by qRT-PCR and western blotting, respectively. Bioinformatic analysis and dual-luciferase reporter assay were used to analyze the combination between miR-139-5p and Myocardin (MYOCD). Results revealed that DBP at 10^-7 M prompted phenotypic switching from contractile to synthetic of VSMCs by inhibiting contractile VSMCs marker genes via suppressing the expression of MYOCD. Moreover, miR-139c-5p directly targeted MYOCD 3'UTR and modulated MYOCD expression. Besides, DBP inhibited the expression of MYOCD and VSMCs marker genes by upregulating miR-139-5p. Collectively, these data suggested that DBP could promote the phenotypic switching from contractile to synthetic of VSMCs in A7r5 cells through miR-139-5p-MYOCD.