The aim of this study was to evaluate the possibility of poly (D, L-lactide-co-glycolide) nanoparticle (NPs) as a gene vector for functional plasmid DNA (pDNA) and to investigate its inhibitory efficacy on experimental choroidal neovascularization (CNV). We developed intravitreal administered, hypoxia-inducible factor 1a (HIF-1a) short hairpin RNA and green fluorescent protein (GFP) co-expressed pDNA-loaded NPs (pshHIF-1a NPs). CNV was induced by laser photocoagulation in 112 rats. The rats were then randomly assigned to be injected intravitreally with phosphate-buffered saline (PBS), blank NPs, naked pDNA, control pDNA NPs and pshHIF-1a NPs, respectively, and non-injection group was set as the control. Immunofluorescence staining, fluorescein fundus angiography and histologic analysis were performed to evaluate the inhibitory efficacy on CNV. The results showed that the expression of GFP preferentially localized in the retinal pigment epithelium cell layer and lasted for 4 weeks. The fluorescein leakage areas of CNV were significantly larger in the PBS, blank NPs, control pDNA NPs, non-injection group and naked pDNA group than in pshHIF-1a NPs group (Po0.01). The mean thickness of the CNV lesions in the intravitreally pshHIF1a NPs-treated group was significantly smaller than other groups (Po0.01). No signs of functional or ultrastructural destruction in retina were detected. Therefore, pshHIF-1a NPs may act as a novel therapeutic option to transfer specific pDNA and inhibit the formation of experimental CNV.

Excessive N-methyl-D-aspartate receptor (NMDAR) activation and the resulting activation of neuronal nitric oxide synthase (nNOS) cause neuronal injury. Homer1b/c facilitates NMDAR-PSD95-nNOS complex interactions, and Homer1a is a negative competitor of Homer1b/c. We report that Homer1a was both upregulated by and protected against NMDA-induced neuronal injury in vitro and in vivo. The neuroprotective activity of Homer1a was associated with NMDA-induced Ca2+ influx, oxidative stress and the resultant downstream signaling activation. Additionally, we found that Homer1a functionally regulated NMDAR channel properties in neurons, but did not regulate recombinant NR1/NR2B receptors in HEK293 cells. Furthermore, we found that Homer1a detached the physical links among NR2B, PSD95 and nNOS and reduced the membrane distribution of NMDAR. NMDA-induced neuronal injury was more severe in Homer1a homozygous knockout mice (KO, Homer1a−/−) when compared with NMDA-induced neuronal injury in wild-type mice (WT, Homer1a+/+). Additionally, Homer1a overexpression in the cortex of Homer1a−/− mice alleviated NMDA-induced neuronal injury. These findings suggest that Homer1a may be a key neuroprotective endogenous molecule that protects against NMDA-induced neuronal injury by disassembling NR2B-PSD95-nNOS complexes and reducing the membrane distribution of NMDARs.