Fingerprinting of the hNGF P61R100E gene expression in rat Dorsal Root Ganglion detected by microarray analysis

Nerve Growth Factor (NGF) is being considered as a therapeutic candidate for Alzheimer's disease (AD) treatment, not merely as a long-lasting cholinergic maintainer and neuroprotective agent but also as a direct anti-amyloidogenic factor. However, the development of a NGF-based therapy for neurodegenerative diseases is limited by the partial access of NGF to the brain and to its potent nociceptive actions in animals and humans. Indeed, NGF is involved in pain transmission and perception. The nociceptive activity of NGF is mediated through the activation of TrkA and p75NTR receptors on sensory nerve endings. Our group recently studied forms of NGF, mutated at residue R100, inspired by the human genetic disease HSAN V (Hereditary Sensory Autonomic Neuropathy Type V), which would allow increasing the dose of NGF without triggering pain. This “painless” hNGF hNGFP61S/R100E displays full neurotrophic and anti-amyloidogenic activities in neuronal cultures, and a reduced nociceptive activity in vivo, via a selective alteration of TrkA versus p75NTR binding and signaling. The molecular mechanism through which pNGF reduces nociceptive activity has never been investigated, therefore we performed gene expression microarray analysis to investigated the effect of hNGF hNGFP61S/R100E delivery in rat Dorsal Root Ganglia. DRG cell cultures were stimulated for experimental procedures using either double mutant hNGFP61S/R100E (n=3 replicates), single mutant hNGFP61S (n=3 replicates) or hNGF wild type (n=2 replicates) at 100 ng/ml concentration for 5 days. At the end of this incubation period, media and cells were collected for RNA extraction and microarray analysis.