DNA/chitosan nanoparticles: internalization and cytokines production by human elutriated monocytes and Thp-1 macrophages

Summary form only given. We have synthesized a non-viral gene delivery system based on chitosan, a cationic biocompatible and biodegradable polymer, comprising amino groups and a plasmid DNA. Chitosan interact with and neutralize the negatively-charged DNA. This results in a more compact DNA structure leading to the formation of nanoparticles with a mean size of 75 nm. Previous studies have shown efficient cell transfection and b galactosidasc expression. The present work is focusing on THP-1 macrophages and human elutriated monocytes interaction with the nanoparticles. This is of primordial importance either in the design of more effective therapeutic strategies for macrophage associated pathogenesis or in establishing new approaches for pharmacological action avoiding macrophages. Internalization and cytokine (IL-6, IL-10, TNF-a) and MMP-2, MMP-9 metalloproteinase production were assessed to investigate the inflammatory reaction. Flow cytometry and fluorescence microscopy were used, after FITC nanoparticle labeling. The results show that most of the nanoparticles are internalized within the first hour by macrophages and that human monocytes are more sensitive than macrophages in terms of cytokine production. This system could be used to modulate macrophage function using gene therapy. This could result in new approaches to treat diseases where macrophage activity plays a major role, such as rheumatoid arthritis and infectious diseases.