CTRP9: An Anti-Atherosclerotic Factor in ApoE Knockout Mice through Oxidative Stress Inhibition

Abstract

Background: C1q/tumor necrosis factor-related protein-9 (CTRP9) is critically involved in the pathophysiology of metabolic and cardiovascular disorders. This investigation aimed to clarify the mechanism underlying the role of CTRP9 in atherosclerosis in apolipoprotein E (ApoE) knockout (KO) mice. Methods: ApoE KO mice were fed a Western diet and injected with a virus which resulted in CTRP9 overexpression or knockdown for 12 weeks. The plasma lipid levels and atherosclerotic plaque areas were measured after the mice were euthanized. Aortas were isolated, and RNA sequencing was performed to identify the differentially expressed genes and related signaling pathways. Finally, plasma oxidative stress factors were measured to demonstrate the reliability of the RNA sequencing results. Results: The plasma lipid levels in the CTRP9 overexpression group did not significantly differ from those in the green fluorescence protein (GFP) group. Markablely, CTRP9 overexpression inhibited atherosclerotic plaque formation in ApoE KO mice, whereas CTRP9 knockdown promoted plaque formation. RNA sequencing analysis identified 3485 differentially expressed genes that were prominently enriched across 55 signaling pathways. Additionally, plasma oxidative stress factors were significantly reduced after CTRP9 overexpression, whereas these factors were increased after CTRP9 knockdown, which was consistent with the results of the RNA sequencing analysis. Conclusions: These findings demonstrated that CTRP9 alleviated inflammation and cholesterol metabolism, which reduced oxidative stress in an atherosclerotic animal model. These beneficial effects may mediate the suppression of lesion development in the aorta.