Induction of heat shock protein-72 by magnetic nanofluid hyperthermia in cultured retinal ganglion cells for neuroprotective treatment in glaucoma

Abstract

Magnetic hyperthermia using superparamagnetic nanoparticle (SPNP) agents is considered a promising biotechnological approach to induce heat shock proteins (HSPs) in a target tissue because it can generate accurately controllable localized heating. Objectives. The main objective of this study is to demonstrate induction of HSPs in cultured retinal ganglion cells (RGCs) by using engineered Mn 0.5 Zn 0.5 Fe 2 O 4 SPNP agents coated with polyethylene glycol (PEG) 500. Methods. The Mn 0.5 Zn 0.5 Fe 2 O 4 nanoparticles were synthesized using a high temperature thermal decomposition method. The AC heating characteristics of PEG 500-coated Mn 0.5 Zn 0.5 Fe 2 O 4 nanoparticles were investigated using an AC solenoid coil-capacitor system. Results. PEG 500-coated SPNPs efficiently penetrated into the cytoplasm of RGCs without causing obvious cytological changes and showed stable and well-saturated self-heating temperature rise characteristics. Immunofluorescent staining images showed that AC magnetic hyperthermia successfully induced HSP72 in RGCs incubated with Mn 0.5 Zn 0.5 Fe 2 O 4 nanoparticles. In Western blot analysis, a significant increase in immunoreactivity was observed for RGCs incubated with SPNPs in a fixed AC magnetic field (f appl = 140 kHz and H appl = 140 Oe). Conclusion. Our results demonstrate that the induction of HSP72 with a magnetic nanofluid hyperthermia could potentially be used as a neuroprotective treatment modality by way of enhancing a natural cytoprotective response.