Targeted suppression of microRNA-33 in lesional macrophages using pH low-insertion peptides (pHLIP) improves atherosclerotic plaque regression

Abstract

Hypoxia and tissue acidification occur in the macrophage-rich regions of advanced atherosclerotic lesions due to the higher oxygen demand of activated immune cells and insufficient oxygen supply. Our group and others originally identified microRNA-33 (miR-33) as critical regulator of cellular lipid homeostasis and lipoprotein metabolism controlling the development of atherosclerosis. Our prior work has demonstrated that pH Low-Insertion Peptides (pHLIP) can be used to direct miR-33 inhibitors to acidic microenvironments and protect against kidney fibrosis. Here we utilize anti-miR-33 conjugated pHLIP constructs to target macrophages located in atherosclerosis plaques. The inhibition of miR-33 using pHLIP-directed targeting increased collagen content and decreased lesional lipid accumulation within atherosclerotic plaques in a murine model of atherosclerosis regression. Single cell RNA sequencing analysis revealed higher expression of fibrotic genes (Col2a1, Col3a1, Fn1, Dcn, etc) and tissue inhibitor of metalloproteinase 3 (Timp3), and downregulation of matrix metallopeptidase 12 (Mmp12) in macrophages from atherosclerotic lesions targeted by pHLIP- anti-miR-33. These results suggest a potential application of pHLIP for treating advanced atherosclerosis via pharmacological inhibition of miR-33.

miR‐33 in cardiometabolic diseases: lessons learned from novel animal models and approaches

“…Additionally, lipid‐laden macrophages within atherosclerotic plaques have also been shown to have low pH, suggesting that these same delivery systems may also be useful for targeted delivery of inhibitors of miR‐33 and other miRNA therapeutics for the treatment of atherosclerosis. Indeed, our recent work has demonstrated that pHLIP‐conjugated inhibitors of miR‐33 can effectively target miR‐33 in the macrophages that make up atherosclerotic plaques leading to stabilization of the lesions (preprint: Zhang et al, 2020).…”