Reduction of Pro-Inflammatory Markers in RAW264.7 Macrophages by Polyethylenimines

The physiological problem of chronic inflammation and its associated pathologies attract ongoing attention with regard to methods for their control. Current systemic pharmacological treatments present problematic side effects. Thus, the possibility of new anti-inflammatory compounds with differing mechanisms of action or biophysical properties is enticing. Cationic polymers, with their ability to act as carriers for other molecules or to form bio-compatible materials, present one such possibility. Although not well described, several polycations such as chitosan and polyarginine, have displayed anti-inflammatory properties. The present work shows the ubiquitous laboratory transfection reagent, polyethylenimine (PEI) and more specifically low molecular weight branched PEI (B-PEI) as also possessing such properties. Using a RAW264.7 murine cell line macrophage as an inflammation model, it is found the B-PEI 700 Da as being capable of reducing the production of several pro-inflammatory molecules induced by the endotoxin lipopolysaccharide. Although further studies are required for elucidation of its mechanisms, the revelation that such a common lab reagent may present these effects has wide-ranging implications, as well as an abundance of possibilities. Cationic polymers from polyethylenimine (PEI) family are popular for their gene delivery capabilities. Here it is found that PEIs have inherent anti-inflammatory properties. Indeed, the branched PEI 700 Da, and to a lesser extent PEI with higher molecular weight (MW) or with a linear topology, are able to reducing several pro-inflammatory markers without significant cytotoxicity. image