Nanocarriers for Protein Delivery to the Cytosol: Assessing the Endosomal Escape of Poly(Lactide-co-Glycolide)-Poly(Ethylene Imine) Nanoparticles.

Marianna Galliani,Giovanni Signore,Chiara Tremolanti

doi:10.3390/nano9040652

Abstract

Therapeutic proteins and enzymes are a group of interesting candidates for the treatment of numerous diseases, but they often require a carrier to avoid degradation and rapid clearance in vivo. To this end, organic nanoparticles (NPs) represent an excellent choice due to their biocompatibility, and cross-linked enzyme aggregates (CLEAs)-loaded poly (lactide-co-glycolide) (PLGA) NPs have recently attracted attention as versatile tools for targeted enzyme delivery. However, PLGA NPs are taken up by cells via endocytosis and are typically trafficked into lysosomes, while many therapeutic proteins and enzymes should reach the cellular cytosol to perform their activity. Here, we designed a CLEAs-based system implemented with a cationic endosomal escape agent (poly(ethylene imine), PEI) to extend the use of CLEA NPs also to cytosolic enzymes. We demonstrated that our system can deliver protein payloads at cytoplasm level by two different mechanisms: Endosomal escape and direct translocation. Finally, we applied this system to the cytoplasmic delivery of a therapeutically relevant enzyme (superoxide dismutase, SOD) in vitro.

Highlights

Protein delivery has witnessed growing interest in the last decades, since proteins and enzymes can find application in the treatment of numerous diseases such as cancer, diabetes, vascular dysfunctions and metabolic disorders [1]
We recently developed an enzyme delivery system based on PLGA and exploiting cross-linked enzyme aggregates (CLEAs) tailored to the delivery of therapeutic enzymes involved in lysosomal storage disorders (LSDs) [16]
The resulting Bovine Serum Albumin (BSA) Cross-linked Aggregates (CLAs) were added to PLGA in acetone, poly(ethylene imine) (PEI) dissolved in dimethyl sulphoxide (DMSO) was added under stirring

Summary

Introduction

Protein delivery has witnessed growing interest in the last decades, since proteins and enzymes can find application in the treatment of numerous diseases such as cancer, diabetes, vascular dysfunctions and metabolic disorders [1]. The simple systemic administration of therapeutic proteins to patients is rarely successful These molecules are prone to degradation in the bloodstream and often fail in reaching their pharmacologic target in the organism. For this reason, efforts have been made to develop micro- and nanosized carriers made of various materials [2,3,4,5,6] able to safely deliver these delicate therapeutics to their site of action [7]. The use of CLEAs, that are known as excellent biocatalysts in the context of sustainable chemistry [17,18], proved to be successful in the drug delivery field, resulting in high encapsulation efficiency, activity retention and enzyme activity recovery of in vitro models of LSDs

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