Phenotypic Knockout of Nerve Growth Factor in Adult Transgenic Mice Reveals Severe Deficits in Basal Forebrain Cholinergic Neurons, Cell Death in the Spleen, and Skeletal Muscle Dystrophy

Abstract

The disruption of the nerve growth factor (NGF) gene in transgenic mice leads to a lethal phenotype (Crowley et al., 1994) and hinders the study of NGF functions in the adult. In this study the phenotypic knockout of NGF in adult mice was achieved by expressing transgenic anti-NGF antibodies, under the control of the human cytomegalovirus promoter. In adult mice, antibody levels are 2000-fold higher than in newborns. Classical NGF targets, including sympathetic and sensory neurons, are severely affected. In the CNS, basal forebrain and hippocampal cholinergic neurons are not affected in the early postnatal period, whereas they are greatly reduced in the adult (55 and 62% reduction, respectively). Adult mice show a reduced ability in spatial learning behavioral tasks. Adult, but not neonatal, transgenic mice further show a new phenotype at the level of peripheral tissues, such as apoptosis in the spleen and dystrophy of skeletal muscles. The analysis of this novel comprehensive transgenic model settles the controversial issue regarding the NGF dependence of cholinergic neurons in adult animals and reveals new NGF functions in adult non-neuronal tissues. The results demonstrate that the decreased availability of NGF in the adult causes phenotypic effects via processes that are at least partially distinct from early developmental effects of NGF deprivation.

Dissecting the involvement of tropomyosin-related kinase A and p75 neurotrophin receptor signaling in NGF deficit-induced neurodegeneration

“…5A) (8,13,21). In 4-to 6-mo-old AD12 mice, however, we found a lower number of AT8-immunoreactive neurons, faintly labeled, in all brain regions described (Fig.…”

“…The variable regions of the light and heavy chains of anti-TrkA mouse mAb MNAC13 (17) were cloned from hybridoma cells and reassembled with human K and γ1 constant regions as described previously (8). Both light-and heavy-chain genes were placed under the transcriptional control of the early region of the human cytomegalovirus promoter, in two separate plasmids (Fig.…”

“…Studies in the AD11 mouse model (8) demonstrated that neutralizing NGF activity in the brain could have consequences beyond direct interference with the cholinergic system, leading to pathological amyloid precursor protein (APP) and tau processing (9). AD11 mice express a highly specific anti-NGF antibody (10,11) in the adult brain, which induces a progressive, NGF-dependent neurodegeneration encompassing several neuropathological features of human AD, including accumulation of Aβ and neuronal expression of hyperphosphorylated, truncated, and insoluble tau (12)(13)(14)(15)(16).…”

Does the term ‘trophic’ actually mean anti-amyloidogenic? The case of NGF

“…59 Interestingly, these anti-NGF transgenic AD11 mice, in which the in vivo phenotypic knockout of mature NGF is achieved by the expression of recombinant neutralizing antibodies, resemble an AD-like neurodegeneration. 60,61 Furthermore, a caspase(s)-mediated truncation of N-terminal tau domain, which possibly interacts with dynactin/dynein motor complex, 62 also occurs in vitro and in vivo on NGF signaling interruption. 48 GSK3b-mediated tau phosphorylation is associated with a proper anterograde organelle transport 63 in NGF-dependent differentiated PC12, and synthetic Ab peptides cause a GSK3b-mediated impairment of mitochondrial transport in hippocampal cultured neurons.…”

Anti-nerve growth factor Ab abrogates macrophage-mediated HIV-1 infection and depletion of CD4+T lymphocytes in hu-SCID mice

“…The ␣D11 hybridoma was prepared according to Cattaneo et al (20). The ␣D11 IgG1 Ig was purified from hybridoma supernatant by precipitation with 29% ammonium sulfate followed by affinity chromatography by using a protein G-Sepharose column (Amersham Pharmacia) and eluted by low pH buffer (10 mM HCl) (20,21). ␣D11 IgG1 fractions were pooled and dialyzed across a Spectra/Por Membrane 12͞14K (Spectrum, Rancho Dominguez, CA) against 10 mM Tris, pH 7.0.…”