# Multilayered Nanocarriers as a New Strategy for Delivering Drugs with Protective and Anti-inflammatory Potential: Studies in Hippocampal Organotypic Cultures Subjected to Experimental Ischemia

## TL;DR

This study explores using nanocarriers to deliver carnosic acid, a neuroprotective compound, to brain cells affected by ischemia, showing potential anti-inflammatory and protective effects.

## Contribution

A new nanocarrier system for delivering carnosic acid to ischemic brain tissue is developed and tested for biocompatibility and anti-inflammatory effects.

## Key findings

- The nanocarriers crossed an artificial blood-brain barrier without toxicity.
- The nanoformulation reduced OGD-induced HIF-1α and IL-1β levels.
- The nanoformulation stimulated anti-inflammatory protein A20 and attenuated NFκB signaling.

## Abstract

Oxidative stress and neuroinflammation play a pivotal role in pathomechanisms of brain ischemia. Our research aimed to formulate a nanotheranostic system for delivering carnosic acid as a neuroprotective agent with anti-oxidative and anti-inflammatory properties to ischemic brain tissue, mimicked by organotypic hippocampal cultures (OHCs) exposed to oxygen–glucose deprivation (OGD). In the first part of this study, the nanocarriers were formulated by encapsulating two types of nanocores (nanoemulsion (AOT) and polymeric (PCL)) containing CA into multilayer shells using the sequential adsorption of charged nanoobjects method. The newly designed nanoparticles possessed favorable physicochemical characteristics as reflected by zeta potential and other parameters. Next, we demonstrated that the newly designed gadolinium-containing nanoparticles were not toxic to OHCs and did not affect the detrimental effects of OGD on the viability of the hippocampal cells. Importantly, they readily crossed the artificial blood–brain barrier based on the human cerebral microvascular endothelial (hCMEC/D3) cell line. Furthermore, the PCL-Gd carnosic acid–loaded nanoparticles displayed anti-inflammatory potential, expressed as decreased OGD-induced HIF-1α and IL-1β levels. Results of the molecular study revealed a complex mechanism of the nanoformulation on ischemia-related neuroinflammation in OHCs, including anti-inflammatory protein A20 stimulation and moderate attenuation of the NFκB signaling pathway. Summing up, this study points to acceptable biocompatibility of the newly designed CA-containing theranostic nanoformulation and emphasizes their interaction with inflammatory processes commonly associated with the ischemic brain.