Multi-targeted neuroprotection by the HSV-2 gene ICP10PK includes robust bystander activity through PI3-K/Akt and/or MEK/ERK-dependent neuronal release of vascular endothelial growth factor and fractalkine.
Hippocampal cultures infected with the DeltaRR vector for the HSV-2 anti-apoptotic gene ICP10PK survive cell death triggered by a wide variety of insults. Survival includes robust protection of uninfected neurons, but the mechanism of this bystander activity is still unclear. Here we report that ICP10PK+ neurons release soluble factors that protect uninfected neurons from NMDA and MPP+-induced apoptosis. Release depends on ICP10PK-mediated activation of the Ras signaling pathways MEK/ERK and PI3-K/Akt, and it was not seen for cultures infected with the ICP10PK negative vector DeltaPK. The released neuroprotective factors include vascular endothelial growth factor (VEGF) and fractalkine, the levels of which were significantly higher in conditioned media from hippocampal cultures infected with DeltaRR (NCM(DeltaRR)) than DeltaPK or phosphate-buffered saline (mock infection). VEGF neutralization inhibited the neuroprotective activity of NCM(DeltaRR), indicating that the VEGF protective function is through neuron-neuron cross-talk. NCM(DeltaRR) also stimulated microglia to release increased levels of IL-10 and decreased levels of TNF-alpha that were protective for uninfected neurons. These release patterns were not seen for microglia given NCM(DeltaRR) in which fractalkine was neutralized, indicating that the fractalkine protective function is through bidirectional neuron-microglia communication. Collectively, the data indicate that DeltaRR is a multiple target strategy to rescue neurons from excitotoxic injury.
Laing
Jennifer M
JM
Department of Pharmacology and Experimental Therapeutics, School of Medicine, University of Maryland, Baltimore, Maryland 21201-1559, USA.
Smith
Cynthia C
CC
Aurelian
Laure
L
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex; D054428:Chemokine CX3CL1 / Q000378:metabolism*; D002522:Chlorocebus aethiops; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004622:Embryo, Mammalian; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005822:Genetic Vectors; D006624:Hippocampus / Q000166:cytology; D020287:In Situ Nick-End Labeling / Q000379:methods; D016753:Interleukin-10 / Q000378:metabolism; D008297:Male; D051379:Mice; D017628:Microglia / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D009154:Mutation; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D051058:Oncogene Protein v-akt / Q000378:metabolism*; D009924:Organ Culture Techniques; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D051381:Rats; D012264:Ribonucleotide Reductases / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection / Q000379:methods; D014404:Tubulin / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D014709:Vero Cells
D054428:Chemokine CX3CL1; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D048049:Extracellular Signal-Regulated MAP Kinases; D016753:Interleukin-10; D016202:N-Methylaspartate; D051058:Oncogene Protein v-akt; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf; D012264:Ribonucleotide Reductases; D014404:Tubulin; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; C488416:Tubb3 protein, rat; C100671:ICP10 protein, herpes simplex virus type 2