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Taking pain out of NGF: a "painless" NGF mutant, linked to hereditary sensory autonomic neuropathy type V, with full neurotrophic activity.

Capsoni S, Covaceuszach S, Marinelli S, Ceci M, Bernardo A, Minghetti L, Ugolini G, Pavone F, Cattaneo A - PLoS ONE (2011)

Bottom Line: NGFR100 mutants maintain identical neurotrophic and neuroprotective properties in a variety of cell assays, while displaying a significantly reduced pain-inducing activity in vivo (n = 8-10 mice/group).We also show that proNGF has a significantly reduced nociceptive activity, with respect to NGF.Both sets of results jointly contribute to elucidating the mechanisms underlying the clinical HSAN V manifestations, and to clarifying which receptors and intracellular signaling cascades participate in the pain sensitizing action of NGF.

View Article: PubMed Central - PubMed

Affiliation: European Brain Research Institute, Rome, Italy.

ABSTRACT
During adulthood, the neurotrophin Nerve Growth Factor (NGF) sensitizes nociceptors, thereby increasing the response to noxious stimuli. The relationship between NGF and pain is supported by genetic evidence: mutations in the NGF TrkA receptor in patients affected by an hereditary rare disease (Hereditary Sensory and Autonomic Neuropathy type IV, HSAN IV) determine a congenital form of severe pain insensitivity, with mental retardation, while a mutation in NGFB gene, leading to the aminoacid substitution R100W in mature NGF, determines a similar loss of pain perception, without overt cognitive neurological defects (HSAN V). The R100W mutation provokes a reduced processing of proNGF to mature NGF in cultured cells and a higher percentage of neurotrophin secreted is in the proNGF form. Moreover, using Surface Plasmon Resonance we showed that the R100W mutation does not affect NGF binding to TrkA, while it abolishes NGF binding to p75NTR receptors. However, it remains to be clarified whether the major impact of the mutation is on the biological function of proNGF or of mature NGF and to what extent the effects of the R100W mutation on the HSAN V clinical phenotype are developmental, or whether they reflect an impaired effectiveness of NGF to regulate and mediate nociceptive transmission in adult sensory neurons. Here we show that the R100 mutation selectively alters some of the signaling pathways activated downstream of TrkA NGF receptors. NGFR100 mutants maintain identical neurotrophic and neuroprotective properties in a variety of cell assays, while displaying a significantly reduced pain-inducing activity in vivo (n = 8-10 mice/group). We also show that proNGF has a significantly reduced nociceptive activity, with respect to NGF. Both sets of results jointly contribute to elucidating the mechanisms underlying the clinical HSAN V manifestations, and to clarifying which receptors and intracellular signaling cascades participate in the pain sensitizing action of NGF.

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Reduced pro-nociceptive responses of hNGF mutants.(A) Mechanical allodynia: dose-response allodynic effects of hNGF after                            intraplantar injection in the hindpaw. (B) Mechanical allodynia: reduced                            allodynic response 5 hours after intraplantar injection of 4                            µg/mouse of hNGFR100E compared to hNGF. (C) Thermal hyperalgesic                            effects in mice injected with hNGFR100E compared to hNGF. (D) Mechanical                            allodynia: reduced allodynic effects of intraplantar injection of                            hproNGF versus hNGF, and of hproNGF mutant R100E versus hproNGF. Points                            represent mean of absolute values ± s.e.m. ANOVA plus post-hoc                            Tukey-Kramer test; * p<0.001 versus saline, # p<0.01 hNGFR100E                            versus hNGF.
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pone-0017321-g005: Reduced pro-nociceptive responses of hNGF mutants.(A) Mechanical allodynia: dose-response allodynic effects of hNGF after intraplantar injection in the hindpaw. (B) Mechanical allodynia: reduced allodynic response 5 hours after intraplantar injection of 4 µg/mouse of hNGFR100E compared to hNGF. (C) Thermal hyperalgesic effects in mice injected with hNGFR100E compared to hNGF. (D) Mechanical allodynia: reduced allodynic effects of intraplantar injection of hproNGF versus hNGF, and of hproNGF mutant R100E versus hproNGF. Points represent mean of absolute values ± s.e.m. ANOVA plus post-hoc Tukey-Kramer test; * p<0.001 versus saline, # p<0.01 hNGFR100E versus hNGF.

Mentions: Mechanical allodynia was measured in adult CD−1 mice exposed to wild type or R100E mutant hNGF by a single injection in the hind-paw. A significant time- and dose-dependent allodynic effect was induced by hNGF (Fig. 5A), as demonstrated by the decreased withdrawal threshold after mechanical stimulation, in the hind-paw ipsilateral to hNGF injection. Controlateral paw showed no significant change in withdrawal thresholds (not shown). Significant allodynia was observed at all doses tested (range  =  0.1–4 µg/injection), except at 0.1 µg/injection, 5 hours after hNGF administration, reaching the maximum for the dose of 4 µg/injection, whose allodynic effect started 3 hours after the injection. As for the hNGFR100E mutant, Fig. 5B shows the paw withdrawal thresholds observed 5 hours after treatments, when the maximal effect by hNGF is observed. hNGFR100E failed to show any allodynic effect, in the dose range tested (Fig. 5B and Fig. S4).


Taking pain out of NGF: a "painless" NGF mutant, linked to hereditary sensory autonomic neuropathy type V, with full neurotrophic activity.

Capsoni S, Covaceuszach S, Marinelli S, Ceci M, Bernardo A, Minghetti L, Ugolini G, Pavone F, Cattaneo A - PLoS ONE (2011)

Reduced pro-nociceptive responses of hNGF mutants.(A) Mechanical allodynia: dose-response allodynic effects of hNGF after                            intraplantar injection in the hindpaw. (B) Mechanical allodynia: reduced                            allodynic response 5 hours after intraplantar injection of 4                            µg/mouse of hNGFR100E compared to hNGF. (C) Thermal hyperalgesic                            effects in mice injected with hNGFR100E compared to hNGF. (D) Mechanical                            allodynia: reduced allodynic effects of intraplantar injection of                            hproNGF versus hNGF, and of hproNGF mutant R100E versus hproNGF. Points                            represent mean of absolute values ± s.e.m. ANOVA plus post-hoc                            Tukey-Kramer test; * p<0.001 versus saline, # p<0.01 hNGFR100E                            versus hNGF.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3046150&req=5

pone-0017321-g005: Reduced pro-nociceptive responses of hNGF mutants.(A) Mechanical allodynia: dose-response allodynic effects of hNGF after intraplantar injection in the hindpaw. (B) Mechanical allodynia: reduced allodynic response 5 hours after intraplantar injection of 4 µg/mouse of hNGFR100E compared to hNGF. (C) Thermal hyperalgesic effects in mice injected with hNGFR100E compared to hNGF. (D) Mechanical allodynia: reduced allodynic effects of intraplantar injection of hproNGF versus hNGF, and of hproNGF mutant R100E versus hproNGF. Points represent mean of absolute values ± s.e.m. ANOVA plus post-hoc Tukey-Kramer test; * p<0.001 versus saline, # p<0.01 hNGFR100E versus hNGF.
Mentions: Mechanical allodynia was measured in adult CD−1 mice exposed to wild type or R100E mutant hNGF by a single injection in the hind-paw. A significant time- and dose-dependent allodynic effect was induced by hNGF (Fig. 5A), as demonstrated by the decreased withdrawal threshold after mechanical stimulation, in the hind-paw ipsilateral to hNGF injection. Controlateral paw showed no significant change in withdrawal thresholds (not shown). Significant allodynia was observed at all doses tested (range  =  0.1–4 µg/injection), except at 0.1 µg/injection, 5 hours after hNGF administration, reaching the maximum for the dose of 4 µg/injection, whose allodynic effect started 3 hours after the injection. As for the hNGFR100E mutant, Fig. 5B shows the paw withdrawal thresholds observed 5 hours after treatments, when the maximal effect by hNGF is observed. hNGFR100E failed to show any allodynic effect, in the dose range tested (Fig. 5B and Fig. S4).

Bottom Line: NGFR100 mutants maintain identical neurotrophic and neuroprotective properties in a variety of cell assays, while displaying a significantly reduced pain-inducing activity in vivo (n = 8-10 mice/group).We also show that proNGF has a significantly reduced nociceptive activity, with respect to NGF.Both sets of results jointly contribute to elucidating the mechanisms underlying the clinical HSAN V manifestations, and to clarifying which receptors and intracellular signaling cascades participate in the pain sensitizing action of NGF.

View Article: PubMed Central - PubMed

Affiliation: European Brain Research Institute, Rome, Italy.

ABSTRACT
During adulthood, the neurotrophin Nerve Growth Factor (NGF) sensitizes nociceptors, thereby increasing the response to noxious stimuli. The relationship between NGF and pain is supported by genetic evidence: mutations in the NGF TrkA receptor in patients affected by an hereditary rare disease (Hereditary Sensory and Autonomic Neuropathy type IV, HSAN IV) determine a congenital form of severe pain insensitivity, with mental retardation, while a mutation in NGFB gene, leading to the aminoacid substitution R100W in mature NGF, determines a similar loss of pain perception, without overt cognitive neurological defects (HSAN V). The R100W mutation provokes a reduced processing of proNGF to mature NGF in cultured cells and a higher percentage of neurotrophin secreted is in the proNGF form. Moreover, using Surface Plasmon Resonance we showed that the R100W mutation does not affect NGF binding to TrkA, while it abolishes NGF binding to p75NTR receptors. However, it remains to be clarified whether the major impact of the mutation is on the biological function of proNGF or of mature NGF and to what extent the effects of the R100W mutation on the HSAN V clinical phenotype are developmental, or whether they reflect an impaired effectiveness of NGF to regulate and mediate nociceptive transmission in adult sensory neurons. Here we show that the R100 mutation selectively alters some of the signaling pathways activated downstream of TrkA NGF receptors. NGFR100 mutants maintain identical neurotrophic and neuroprotective properties in a variety of cell assays, while displaying a significantly reduced pain-inducing activity in vivo (n = 8-10 mice/group). We also show that proNGF has a significantly reduced nociceptive activity, with respect to NGF. Both sets of results jointly contribute to elucidating the mechanisms underlying the clinical HSAN V manifestations, and to clarifying which receptors and intracellular signaling cascades participate in the pain sensitizing action of NGF.

Show MeSH
Related in: MedlinePlus