Dexamethasone‐Conjugated Polyamidoamine Dendrimer for Delivery of the Heme Oxygenase‐1 Gene into the Ischemic Brain

Abstract

Heme oxygenase-1 (HO-1) has anti-apoptotic and anti-inflammatory effects. In this study, the HO-1 gene was delivered into the brain using dexamethasone-conjugated polyamidoamine generation 2 (PAMAM G2-Dexa) for the treatment of ischemic stroke. PAMAM G2-Dexa formed stable complexes with plasmid DNA (pDNA). The pDNA delivery efficiency of PAMAM G2-Dexa was higher than that of polyethylenimine (PEI25k, 25 kDa), dexamethasone-conjugated PEI (PEI-Dexa), and PAMAM G2 in Neuro2A cells. Therapeutic effect of PAMAM G2-Dexa/pHO-1 complexes was evaluated in a stroke animal model. PAMAM G2-Dexa delivered pHO-1 more efficiently into the ischemic brain than PEI25k and PEI-Dexa with higher therapeutic effect. Therefore, PAMAM G2-Dexa/pHO-1 complexes may be useful for ischemic stroke gene therapy.

Delivery of Hypoxia-Inducible Heme Oxygenase-1 Gene for Site-Specific Gene Therapy in the Ischemic Stroke Animal Model

“…In previous studies, PAMAM-Dexa and PEI-Dexa were shown to have an anti-inflammatory effect due to the dexamethasone moiety (17). The anti-inflammatory effect of dexamethasone is beneficial to decrease the inflammatory reaction in the ischemic brain (10).…”

“…Preparation of pDNA pβ-Luc, pSV-HO-1, and pEpo-SV-HO-1 were constructed previously (17,25). pEmpty was pSI, which was purchased from Promega (Madison, WI, USA).…”

“…Conjugation of dexamethasone to PAMAM G2 and PEI2k was performed as described previously (17). Briefly, PAMAM G2 or PEI2k was mixed with 2 equivalents of Traut's reagent and 2 equivalents of dexamethasone 21-mesylate (Seraloids, Saint Louis, MO, USA) in anhydrous DMSO.…”

“…To enhance the anti-inflammatory effect, dexamethasone was also conjugated to PAMAM G2 (16,17), since PAMAM is reported to have an anti-inflammatory effect by reducing proinflammatory cytokine levels (18). As a result, dexamethasone-conjugated PAMAM G2 (PAMAM-Dexa) had higher anti-inflammatory effect than PEI-Dexa (17). In addition, the gene delivery efficiency of PAMAM-Dexa was higher than that of PEI-Dexa.…”

“…Furthermore, the dexamethasone in PEI-Dexa has an anti-inflammatory effect (10,14,15), indicating that PEI-Dexa might be an anti-inflammatory drug as well as a gene carrier. To enhance the anti-inflammatory effect, dexamethasone was also conjugated to PAMAM G2 (16,17), since PAMAM is reported to have an anti-inflammatory effect by reducing proinflammatory cytokine levels (18). As a result, dexamethasone-conjugated PAMAM G2 (PAMAM-Dexa) had higher anti-inflammatory effect than PEI-Dexa (17).…”