# Targeted lipid nanoparticles containing IL-10 mRNA improve outcomes in experimental intracerebral hemorrhage

## TL;DR

This study explores using lipid nanoparticles carrying IL-10 mRNA to reduce brain inflammation after intracerebral hemorrhage in mice, showing promising results.

## Contribution

A novel targeted delivery system using VCAM-decorated lipid nanoparticles to deliver IL-10 mRNA to inflamed brain endothelium after ICH.

## Key findings

- VCAM-LNPs delivered IL-10 mRNA to the brain 10x more effectively than nonspecific LNPs.
- Treatment reduced hematoma size by ~69% and improved motor behavior by ~65% in mice.
- VCAM-LNPs targeted infiltrated macrophages and neutrophils and increased IL-10 levels in the brain.

## Abstract

Intracerebral hemorrhage (ICH) is a lethal and highly morbid form of stroke for which there is no disease-specific therapy. Inflammation after ICH is an important mechanism of secondary damage, and the inflamed endothelium in ICH is a promising therapeutic target as it is the gateway for inflammation in the brain. Systemic therapies that target inflammation have been unsuccessful in stroke, in part due to side effects or poor brain delivery. We hypothesized that targeting mRNA encoding IL-10, a potent anti-inflammatory cytokine, to the brain vasculature would improve outcomes in an experimental mouse model of ICH. We manufactured lipid nanoparticles (LNPs) using microfluidics, packaged them with IL-10 mRNA, and decorated them with antibodies against vascular cellular adhesion molecule (VCAM), which can bind the inflamed brain endothelium after ICH. VCAM LNPs distributed to the brain ~4x more than nonspecific LNPs and expressed their cargo in the brain at 10x higher levels. Treatment with VCAM-LNPs containing IL-10 mRNA led to ~69% reduction in hematoma size at 72 hours after ICH and ~65% improvement in motor behavior in our model, with no improvement in vascular leakage. Finally, we observed that VCAM-LNPs primarily target infiltrated macrophages and neutrophils. VCAM-IL10-LNPs significantly increased plasma and brain levels of IL10. Our data provide preliminary data for a promising therapeutic and delivery strategy for ICH, and shed light on the relationship between inflammation and vascular leakage. Future experiments will seek to understand how serial dosing affects LNP expression in our model and whether treatment at later time points after ICH can still confer therapeutic effects.