Toward reliable low-density lipoprotein ultrastructure prediction in clinical conditions: A small-angle X-ray scattering study on individuals with normal and high triglyceride serum levels

The Soret coefficient of human low-density lipoprotein in solution: a thermophilic behavior

Thermodiffusion, or Soret effect, is the physical phenomenon of matter gradients originated by the migration of chemical species induced by thermal gradients. Thermodiffusion has been widely applied in the study of colloidal suspensions. In this study, we investigate the termodiffusion behavior of low-density lipoprotein (LDL) particles, by the Soret coefficient measurement. It is a new approach to studies of plasma lipoproteins. The experimental work was based on thermal- and Soret-lens effects. These effects were induced by laser irradiation of the samples, at two different time scales, in a Z-scan setup. LDL samples were analyzed under physiological conditions, notedly, ionic strength and pH, and at different temperatures. Temperature dependence of Soret coefficient showed a slight decrease in the absolute value of this coefficient, as a function of temperature increasing. However, its sign does not change at the temperatures investigated (15, 22.5 and 37.5 °C). The results show that LDL particles exhibit thermophilic behavior. The origin of this thermophilic behavior is not yet completely understood. We discuss some aspects that can be related with the Soret effect in LDL samples.

miR-125a-3p aggravates ox-LDL-induced HUVEC injury through BAMBI

Atherosclerosis (AS) is a chronic inflammatory disease characterized by the formation of atherosclerotic plaque in the intima of arteries. Among the known regulators of atherosclerosis, microRNAs (miRNAs) have been reported to play critical roles in lipoprotein homeostasis and plaque formation. But the roles of microRNA-125a-3p (miR-125a-3p) in the pathogenesis of AS remain unknown. Human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL) to construct the vascular injury model of AS pathogenesis in vitro. miR-125a-3p and BMP and activin membrane-bound inhibitor (BAMBI) expression levels in HUVECs were then measured by quantitative real-time polymerase chain reaction and western blot. The viability and apoptosis of HUVECs were analyzed by Cell Counting Kit-8 assay, TUNEL assay, and flow cytometry, respectively. The relationship between BAMBI 3'-untranslated region and miR-125a-3p was validated by dual luciferase reporter gene assay. miR-125a-3p expression was raised in HUVECs induced with ox-LDL. In HUVECs, miR-125a-3p enhanced the effects of ox-LDL treatment on repressing the viability and promoting the apoptosis of cells. Additionally, BAMBI was confirmed as a direct target of miR-125a-3p and BAMBI overexpression reversed the effects of miR-125a-3p on HUVECs. miR-125a-3p aggravates the dysfunction of HUVECs induced by ox-LDL via BAMBI, which implies that miR-125a-3p is involved in the pathogenesis of AS.