Targeted suppression of miRNA-33 using pH low-insertion peptides improves atherosclerosis regression

Rationale: miRNA therapeutics have gained attention during the past decade. These oligonucleotide treatments can modulate the expression of miRNAs in vivo and could be used to correct the imbalance of gene expression found in human diseases such as obesity, metabolic syndrome and atherosclerosis. The in vivo efficacy of current anti-miRNAs technologies hindered by physiological and cellular barriers to delivery into targeted cells and the nature of miRNAs that allows one to target an entire pathway that may lead to deleterious off-target effects. For these reasons, novel targeted delivery systems to inhibit miRNAs in specific tissues will be important for developing effective therapeutic strategies for numerous diseases including atherosclerosis. Objective: To explore the application of anti-miR-33 (miR-33-5p) conjugated pH Low-Insertion Peptides (pHLIP) constructs for the specific targeting of macrophages located in vascular lesions in the regression of atherosclerosis. Methods and Results: The anti-miR-33 conjugated pHLIP constructs are preferentially delivered to atherosclerotic plaques macrophages. The inhibition of miR-33 using pHLIP-directed macrophage targeting improves atherosclerosis regression by increasing collagen content and decreased lipid accumulation within vascular lesions. Single cell RNA sequencing analysis revealed higher expression of fibrotic genes (Col2a1, Col3a1, Col1a2, Fn1, 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. Conclusions: This study provides proof of principle for the application of pHLIP for treating advanced atherosclerosis via pharmacological inhibition of miR-33 in macrophages that avoids the deleterious effects in other metabolic tissues. This may open new therapeutic opportunities for atherosclerosis-associated cardiovascular diseases via selective delivery of other protective miRNAs. scRNA-seq of whole cells from atherosclerotic plaques of Ldlr-/- mouse treated with anti-miR-33pHLIP or ScrpHLIP