Modifying a Commonly Expressed Endocytic Receptor Retargets Nanoparticles in Vivo

Abstract

Nanoparticles are often targeted to receptors expressed on specific cells, but few receptors are (i) highly expressed on one cell type and (ii) involved in endocytosis. One unexplored alternative is manipulating an endocytic gene expressed on multiple cell types; an ideal gene would inhibit delivery to cell type A more than cell type B, promoting delivery to cell type B. This would require a commonly expressed endocytic gene to alter nanoparticle delivery in a cell type-dependent manner in vivo; whether this can occur is unknown. Based on its microenvironmental regulation, we hypothesized Caveolin 1 (Cav1) would exert cell type-specific effects on nanoparticle delivery. Fluorescence was not sensitive enough to investigate this question, and as a result, we designed a platform named QUANT to study nanoparticle biodistribution. QUANT is 10× more sensitive than fluorescence and can be multiplexed. By measuring how 226 lipid nanoparticles (LNPs) delivered nucleic acids to multiple cell types in vivo in wild-type and Cav1 knockout mice, we found Cav1 altered delivery in a cell-type specific manner. Cav1 knockout did not alter LNP delivery to lung and kidney macrophages but substantially reduced LNP delivery to Kupffer cells, which are liver-resident macrophages. These data suggest caveolin-mediated endocytosis of nanomedicines by macrophages varies with tissue type. These results suggest manipulating receptors expressed on multiple cell types can tune drug delivery.

Lipid nanoparticle technology for therapeutic gene regulation in the liver

“…The term "liver gene therapy" is often used to unilaterally describe all gene therapy approaches for treating diseases originating in hepatocytes. Although hepatocytes are the most prominent cell type within the liver, several other cell types can interact with nanoparticles and affect their performance [41][42][43][44]. It is therefore recommended that scientists expand their LNP studies to include single cell quantification rather than the whole liver.…”

Nanoparticles Containing Oxidized Cholesterol Deliver mRNA to the Liver Microenvironment at Clinically Relevant Doses

“…As an additional control, we assessed the potency of LNP1 compared to a previously reported LNP with potency at 0.2 mg / kg (Figure 3M); LNP1 outperformed this positive control LNP (Figure 3N–Q) between 14- and 77-fold within the liver microenvironment. We then used QUANT [20] , a highly sensitive biodistribution system. to assess LNP biodistribution, for LNP1, LNP2, and LNP1-Chol.…”

Nanoparticles containing constrained phospholipids deliver mRNA to liver immune cells in vivo without targeting ligands

“…We investigated whether the amount of LNPs that reached the cells (i.e., biodistribution) mirrored the functional readouts. We therefore measured the LNP biodistribution of the 109 LNP pool across liver cell-types using QUANT, a technique used to quantify LNP biodistribution using droplet digital PCR (ddPCR) 25 ; we previously compared QUANT biodistribution readouts to fluorescent biodistribution readouts and found QUANT to be more sensitive. 25 After isolating the tdTomato + liver cells using FACS, we used ddPCR to quantify the absolute amount of DNA barcode in Kupffer cells, liver endothelial cells, and hepatocytes.…”