Heterozygosity for ADP-ribosylation factor 6 suppresses the burden and severity of atherosclerosis

Abstract

Atherosclerosis is the root cause of major cardiovascular diseases (CVD) such as myocardial infarction and stroke. ADP-ribosylation factor 6 (Arf6) is a ubiquitously expressed GTPase known to be involved in inflammation, vascular permeability and is sensitive to changes in shear stress. Here, using atheroprone, ApoE-/- mice, with a single allele deletion of Arf6 (HET) or wildtype Arf6 (WT), we demonstrate that reduction in Arf6 attenuates atherosclerotic plaque burden and severity. We found that plaque burden in the descending aorta was lower in HET compared to WT mice (p˂0.001) after the consumption of an atherogenic Paigen diet for 5 weeks. Likewise, luminal occlusion, necrotic core size, plaque grade, elastic lamina breaks, and matrix deposition were lower in the aortic root atheromas of HET compared to WT mice (all p≤0.05). We also induced advanced human-like complex atherosclerotic plaque in the left carotid artery using partial carotid ligation surgery and found that atheroma area, plaque grade, intimal necrosis, intraplaque hemorrhage, thrombosis, and calcification were lower in HET compared to WT mice (all p≤0.04). Our findings suggest that the atheroprotection afforded by Arf6 heterozygosity may result from reduced immune cell migration (all p≤0.005) as well as endothelial and vascular smooth muscle cell proliferation (both p≤0.001) but independent of changes in circulating lipids (all p≥0.40). These findings demonstrate a critical role for Arf6 in the development and severity of atherosclerosis and suggest that Arf6 inhibition can be explored as a novel therapeutic strategy for the treatment of atherosclerotic CVD.

Endothelial cell‐specific reduction in mTOR ameliorates age‐related arterial and metabolic dysfunction

“…Protein lysates were prepared from primary lung endothelial cells using ice‐cold RIPA buffer (Sigma Aldrich) containing proteases and phosphatase inhibitor cocktails (Thermo Fisher) as described previously (Gogulamudi et al., 2023 ). Protein concentration was measured using BCA assay (Thermo Fisher) according to the manufacturer's protocol.…”

Endothelial-Specific Reduction in Arf6 Impairs Insulin-Stimulated Vasodilation and Skeletal Muscle Blood Flow Resulting in Systemic Insulin Resistance in Mice

“…18,19 Hyperactivation of Arf6 has been reported in multiple human diseases and animal models of human disease, including cancer metastasis, sepsis, diabetic retinopathy, atherosclerosis, and neuroinflammatory diseases. [18][19][20][21][22] The known role of Arf6 in endothelial functions and inflammatory signaling suggests that it may be a therapeutic target for many diseases. In the endothelium, Arf6 modulates noncanonical, NF-κB-independent, inflammatory signaling.…”