Increased PIP3 activity blocks nanoparticle mRNA delivery

Abstract

The biological pathways that affect drug delivery in vivo remain poorly understood. We hypothesized that altering cell metabolism with phosphatidylinositol (3,4,5)-triphosphate (PIP3), a bioactive lipid upstream of the metabolic pathway PI3K (phosphatidylinositol 3-kinase)/AKT/ mTOR (mammalian target of rapamycin) would transiently increase protein translated by nanoparticle-delivered messenger RNA (mRNA) since these pathways increase growth and proliferation. Instead, we found that PIP3 blocked delivery of clinically-relevant lipid nanoparticles (LNPs) across multiple cell types in vitro and in vivo. PIP3-driven reductions in LNP delivery were not caused by toxicity, cell uptake, or endosomal escape. Interestingly, RNA sequencing and metabolomics analyses suggested an increase in basal metabolic rate. Higher transcriptional activity and mitochondrial expansion led us to formulate two competing hypotheses that explain the reductions in LNP-mediated mRNA delivery. First, PIP3 induced consumption of limited cellular resources, “drowning out” exogenously-delivered mRNA. Second, PIP3 triggers a catabolic response that leads to protein degradation and decreased translation.

Highly Photoluminescent Nitrogen- and Zinc-Doped Carbon Dots for Efficient Delivery of CRISPR/Cas9 and mRNA

“…Messenger RNA (mRNA) delivery holds great promise for the prevention and treatment of various diseases by either replacing or supplementing missing or inadequately expressed endogenous proteins . Its advantages, including no genomic integration, faster protein expression, and no need for nuclear uptake, − have enabled the design of safe and highly efficient delivery systems based on mRNA to develop a wide range of therapeutic applications.…”

Drug delivery systems for RNA therapeutics

“…A second way to improve the nanoparticle discovery pipeline is to understand which small animals best predict delivery in a non-human primate. Species variability can derive from physiological differences in basal metabolic rates 212 , which can affect nanoparticle delivery 213 – 215 , or differences in serum lipids 216 , which can affect the colloidal stability, biodistribution, cellular interactions, toxicity and clearance of the resulting nanoparticle coronas 217 . Additional species variability probably derives from the mass of a given tissue, relative to the total animal weight, which is not conserved (Fig.…”

Therapeutic RNA Delivery for COVID and Other Diseases

“…Specifically, several lines of evidence now suggest that pathways governing endogenous mRNA translation or metabolism may influence the efficiency with which LNP‐mediated mRNA delivery leads to functional protein. [ 21–26 ] In one example, researchers knocked down genes related to the mammalian target of rapamycin (mTOR) pathway in order to investigate their impact on LNP functional delivery. [ 21 ] They found that knocking down Rab4a and Rab5a, proteins necessary for early endosomal trafficking and endosomal recycling, had no impact on LNP delivery, whereas knocking down Rab7a, a protein necessary for endosomal maturation and late endosomal trafficking, significantly reduced LNP delivery.…”

“…Additional data support the hypothesis that mTOR signaling, or signaling pathways that interact with the mTOR pathway, may influence delivery. [ 22 ] Recently, scientists found that the bioactive lipid phosphatidylinositol (3,4,5)‐triphosphate (PIP3) reduces LNP‐mediated mRNA delivery by changing a cell's metabolic state. [ 22 ] Based on transcriptomic and metabolomic analyses, researchers concluded that reductions in LNP delivery could be mediated by two potential mechanisms: first, that PIP3 induces consumption of cellular resources, limiting resources available for the translation of exogenously delivered mRNA; second, that PIP3 induces a catabolic cell response that triggers protein degradation and decreased translation.…”

“…[ 22 ] Recently, scientists found that the bioactive lipid phosphatidylinositol (3,4,5)‐triphosphate (PIP3) reduces LNP‐mediated mRNA delivery by changing a cell's metabolic state. [ 22 ] Based on transcriptomic and metabolomic analyses, researchers concluded that reductions in LNP delivery could be mediated by two potential mechanisms: first, that PIP3 induces consumption of cellular resources, limiting resources available for the translation of exogenously delivered mRNA; second, that PIP3 induces a catabolic cell response that triggers protein degradation and decreased translation. Although the relative importance of these two mechanisms is unknown, this sharp reduction in protein translation in PIP3‐altered cells suggests that the metabolic state of a cell can alter LNP delivery.…”