Ox-LDL Aggravates the Oxidative Stress and Inflammatory Responses of THP-1 Macrophages by Reducing the Inhibition Effect of miR-491-5p on MMP-9

Abstract

Background: Oxidized low-density lipoprotein (ox-LDL) can induce oxidative stress and inflammatory responses in macrophages to facilitate the genesis and development of atherosclerosis. However, the intermediate links remain unclear. MiR-491-5P can inhibit matrix metalloproteinase 9 (MMP-9); however, it remains unclear whether ox-LDL enhances MMP-9 expression and aggravates the oxidative stress and inflammatory responses under the mediating effect of miR-491-5P.Method: THP-1 macrophages were divided into 10 groups: blank (control), model (ox-LDL), miR-491-5P high-expression (miR-491-5P mimic), miR-491-5P control (mimic-NC), MMP-9 high-expression (MMP-9-plasmid), MMP-9 control (plasmid-NC), miR-491-5P+plasmid-NC, miR-491-5P+ MMP-9-plasmid, MMP-9 gene silencing (MMP-9-siRNA), and gene silencing control (siRNA-NC). The cells were transfected for 48 h and then treated with 50 μg/mL of ox-LDL for 24 h. MMP-9 mRNA and miR-491-5P expression levels in the cells were detected using reverse transcription-quantitative polymerase chain reaction, and the MMP-9 levels were detected with western blotting. The levels of oxidative stress factors (malondialdehyde [MDA]), reactive oxygen species (ROS), and antioxidant factors (superoxide dismutase [SOD]), and the expression levels of inflammatory factors (tumor necrosis factor [TNF-α] and interleukin-1β and−6 [IL-1β and IL-6]) in the supernatant were detected with enzyme-linked immunosorbent assay.Results: MDA, ROS, TNF-α, IL-1β, IL-6, and MMP-9 levels were increased, SOD activity was reduced, and miR-491-5P expression was downregulated in the ox-LDL group compared to the control group. In the miR-491-5P mimic group, the MDA, ROS, TNF-α, IL-1β, IL-6, MMP-9 mRNA and protein levels were downregulated, and SOD activity was enhanced compared to the ox-LDL group. MMP-9-plasmid elevated the MDA, ROS, TNF-α, IL-1β, IL-6, MMP-9 mRNA and protein levels, and downregulated SOD activity and miR-491-5P expression. Following transfection with MMP-9-siRNA, the MMP-9-plasmid outcomes were nullified, and the resulting trends were similar to the miR-491-5p simulation group. Oxidative stress and inflammatory responses were higher in the miR-491-5P mimic+MMP-9-plasmid co-transfection group than in the miR-491-5P mimic group.Conclusion: Ox-LDL aggravates the oxidative stress and inflammatory responses of THP-1 macrophages by reducing the inhibition effect of miR-491-5p on MMP-9.

Paeoniflorin alleviates liver injury in hypercholesterolemic rats through the ROCK/AMPK pathway

“…Massive lipid deposition in macrophages leads mitochondrial dysfunction and accelerates ROS production. The ROS converts LDL into a large amount of oxidized low-density lipoprotein (ox-LDL), and ox-LDL can cause inflammation and oxidative stress ( Liao et al, 2021 ), which forms a vicious cycle. Thus, we tested the indexes related to oxidative stress and inflammation.…”

“…The pathogenesis of hypercholesterolemia remains unclear, and oxidative stress and the inflammatory response are often mentioned as key factors ( Zhang et al, 2022 ). Studies have shown that excessive accumulation of cholesterol in the blood leads to increased reactive oxygen species (ROS) production ( Li et al, 2020 ), and these highly reactive species mediate low-grade inflammation ( Reyes-Gordillo et al, 2017 ) ( Liao et al, 2021 ) ( Incalza et al, 2018 ). Systematic oxidative stress and inflammatory response impair lipid metabolism, and thus, lipids accumulate in the liver ( Abbasi et al, 2021 ).…”

Serum microRNA miR-491-5p/miR-206 Is Correlated with Poor Outcomes/Spontaneous Hemorrhagic Transformation after Ischemic Stroke: A Case Control Study

“…MiR491-5p mediates the regulation of MMP-9 expression [ 25 ]. It can inhibit the expression of target mRNAs by binding to them, thus exerting a regulatory effect and achieving targeted inhibition of MMP-9 expression [ 26 , 27 ]. The interference of miR-491-5p binding to MMP-9 may confer an increased risk for atherosclerotic cerebral infarction [ 27 ].…”

Understanding the functional inflammatory factors involved in therapeutic response to immune checkpoint inhibitors for pan-cancer

“…Third, some ECM components influence inflammatory factor levels. For example, MMP-9 increases TNF-α, IL-1β, IL-6 levels ( Liao et al, 2021 ). Low doses of collagen synergize with CXCL12 to induce the release of CD40L via p38-MAPK activation ( Nakashima et al, 2020 ).…”