# Engineered Liposomal Delivery of Human ACE2 Across the Blood–Brain Barrier Attenuated Neurogenic Hypertension

## TL;DR

Researchers developed a liposomal delivery system to transport the ACE2 gene across the blood-brain barrier, successfully reducing neurogenic hypertension in rats.

## Contribution

A novel dual-functionalized liposomal system was created to deliver ACE2 across the blood-brain barrier for treating hypertension.

## Key findings

- Tf-Pen-liposomes significantly enhanced gene transfection and BBB transport in vitro and in vivo.
- Intravenous Tf-Pen-Lip-pACE2 reduced Ang II-induced hypertension and sympathetic overactivation.
- ACE2 expression in the PVN was increased by the liposomal delivery system.

## Abstract

The blood–brain barrier (BBB) restricts the entry of therapeutic agents into the brain cardiovascular regulatory region, potentially contributing to drug-resistant hypertension. Objective: The objective of this study was to overcome this limitation by modifying PEGylated liposomes with transferrin (Tf) to facilitate Tf receptor binding at the BBB and penetratin (Pen), a cell-penetrating peptide, to enhance neuronal uptake. Methods: This study evaluated the efficacy of Tf-Pen-liposomes in delivering angiotensin-converting enzyme 2 (ACE2) or EGFP (control) genes across the BBB in rats. In addition, the therapeutic effect of intravenous administration of Tf-Pen-Lip carrying plasmid DNA encoding ACE2 (Tf-Pen-Lip-pACE2) was tested in a neurogenic hypertension model induced by intracerebroventricular (ICV) infusion of angiotensin II (Ang II) via osmotic pump implantation and brain cannulation. Results: Conjugation with Tf and Pen significantly enhanced liposome-mediated gene transfection in cultured cells and increased transport across an in vitro BBB model. In vivo, intravenous administration of Tf-Pen-Lip-pACE2 or Tf-Pen-Lip-pGFP successfully elevated ACE2 or EGFP expression, respectively, in the hypothalamic paraventricular nucleus (PVN). Chronic ICV infusion of Ang II produced a sustained increase in blood pressure and heart rate, accompanied by sympathetic overactivation and elevated arginine vasopressin (AVP) secretion, hallmarks of neurogenic hypertension. Notably, intravenous Tf-Pen-Lip-pACE2 treatment dramatically attenuated Ang II–induced neurogenic hypertension, whereas Tf-Pen-Lip-pGFP had no effect on pressor responses, sympathetic activity, or AVP secretion. Conclusions: This dual-functionalized liposomal delivery system effectively transported the ACE2 gene across the BBB into the brain, increased ACE2 expression, and markedly attenuated neurogenic hypertension following systemic administration.