The HSV-2 protein ICP10PK prevents neuronal apoptosis and loss of function in an in vivo model of neurodegeneration associated with glutamate excitotoxicity

Abstract

Excessive glutamate receptor activation results in neuronal death, a process known as excitotoxicity. Intrastriatal injection of N-methyl-D-aspartate (NMDA) is a model of excitotoxicity. We used this model to examine whether excitotoxic injury is inhibited by the anti-apoptotic herpes simplex virus type 2 (HSV-2) protein, ICP10PK, delivered by the replication incompetent HSV-2 vector, ΔRR. Intrastriatal ΔRR administration (2500 plaque forming units) was nontoxic and did not induce microglial activation five days after injection. Intrastriatal injection of ΔRR with NMDA or four hours after NMDA injection showed increased neuronal survival and decreased mitochondrial damage compared to injection of NMDA alone. Neuroprotection was due to the inhibition of NMDAinduced apoptosis through ERK activation. ΔRR treated mice did not develop NMDA-associated behavioral deficits. The data suggests that ΔRR is a promising platform for treatment of acute neuronal injury.

Pseudorabies virus US3-mediated inhibition of apoptosis does not affect infectious virus production

“…For HSV-2, besides US3 (Asano et al, 1999(Asano et al, , 2000Hata et al, 1999;Murata et al, 2002), ICP10 (Golembewski et al, 2007;Perkins et al, 2002aPerkins et al, , b, 2003 has been reported to protect cells from apoptosis. It will be interesting to dissect the potential anti-apoptotic function of different PRV proteins and to determine their combined effect on infectious virus production.…”

ICP10PK inhibits calpain-dependent release of apoptosis-inducing factor and programmed cell death in response to the toxin MPP+

“…Previous studies had shown that ICP10PK overrides caspase-dependent cascades, [11][12][13][14][15][16][17] but its ability to inhibit caspase-independent death programs is still unknown. In a first series of experiments to address this question, neuronally differentiated PC12, PC139 and PC47 cells were treated with MPP+, exposed to the mitochondrionselective dye MitoTracker Red 580 and stained with Alexa Fluor 488-labeled AIF antibody, as described in 'Materials and methods'.…”

“…To examine whether ICP10PK inhibits MPP+-induced cell death, neuronally differentiated PC12 cells were treated with the ICP10PK vector DRR, that is neuroprotective in other toxicity paradigms, 11,[13][14][15][16][17] and exposed to MPP+ (1 mM, 24 h) at 24 h after infection. PCD was evaluated based on DNA fragmentation measured by terminal transferase dUTP nick-end labeling (TUNEL).…”

“…The percent TUNEL + cells was calculated by counting five randomly selected fields (at least 250 cells, in a 3 mm 2 area) and results are expressed as percent TUNEL + cells/total cells (determined by 46-diamidino-2-phenyl indole (DAPI) staining) ± s.e.m. 11,12,16 The vector deleted in ICP10PK (DPK) and cells mock-infected with phosphate-buffered saline (PBS) served as control. The percent TUNEL + cells induced by MPP+ was significantly reduced by DRR (Po0.001), but not DPK, suggesting that ICP10PK inhibits MPP+-induced toxicity ( Figure 1a).…”

“…Neuroprotection was seen in cultured cells, organotypic slices and animal models, and it was through the activation of redundant survival pathways. [11][12][13][14][15][16] Most importantly, the surviving neurons retained synaptic function, 11,13,14 suggesting that ICP10PK has strong and versatile neuroprotective potential that might be harnessed in the treatment of PD. However, the ability of ICP10PK to inhibit caspaseindependent PCD is still unknown.…”