Design of painless nerve growth factor mutants



Design of painless nerve growth factor mutants




Nerve Growth Factor, Pain,  Human genetic disease, Binding affinity TrkA, p75NTR

Scuola Internazionale Superiore di Studi Avanzati, Trieste (Italy); Lay Line Genomics S.p.A., Roma (Italy); European Brain Research Institute, Roma (Italy);

Nerve Growth Factor (NGF) is the prototype member of the structurally related neurotrophin family, that regulate many functions of neuronal cells. NGF exerts its effects in responsive cells by interacting with either one or both of two cell surface receptors: the tyrosine kinase TrkA and p75NTR. Among its numerous actions in the central and peripheral nervous system, NGF is involved in pain transduction mechanisms and plays a key role in many persistent pain states, The pro-nociceptive activity of NGF has been demonstrated in humans, in the course of clinical trials, limiting severely the therapeutical applications of NGF. The physiological relevance of the NGF system as a crucial regulator of pain has been highlighted by genetic evidence in humans. Rare forms of congenital insensitivity to pain (human sensory and autonomic neuropathy type IV and V, HSAN IV and HSAN V) are caused by mutations in the NTRK1 gene, coding for the NGF receptor, TrkA, and the NGFB gene, respectively. HSAN IV NTRK1 mutations abolish or reduce TrkA responsiveness to NGF. The recently described single nucleotide missense mutation in the NGFB gene, found in HSAN V patients, results in the aminoacid R to W substitution at position 100 of mature NGF protein and its impact on NGF functions is unclear. Homozygous cases for this mutation show impaired temperature sensation and an almost complete loss of deep pain perception, leading to joint destruction and multiple painless fractures, while heterozygous members of the family showed a milder pain insensitivity. Importantly, HSAN V patients, unlike HSAN IV patients, show no mental retardation nor other neurological and cognitive deficits. We deduced that these genetic data could, in principle, provide a basis for the design of a painless NGF variant of therapeutic interest. In order to gain insights into the functional consequences of the HSAN V NGF mutation, a series of hNGFR100 mutants were expressed in Escherichia coli and the in vitro receptor binding studies, and the in vitro receptor binding profile of hNGFR100 and hproNGF variant being characterized.

Covaceuszach S, Capsoni S, Marinelli S, Pavone F, Ceci M, Ugolini G, Vignone D, Amato G, Paoletti F, Lamba D, Cattaneo, A. In vitro receptor binding properties of a painless NGF mutein, linked to Hereditary Sensory Autonomic Neuropathy type V. Biochemical Biophysical Research Communications (2010) 391, 824.




Doriano Lamba
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Last Updated (Tuesday, 21 December 2010 17:00)