Brain-derived neurotrophic factor: subcellular compartmentalization and interneuronal transfer as visualized with anti-peptide antibodies.

Abstract

The recent cloning of a second member of the nerve growth factor family, brain-derived neurotrophic factor (BDNF), has prompted investigation into the cells that express this factor's mRNA and protein. In The purification and cloning of brain-derived neurotrophic factor (BDNF) (1) and the subsequent cloning of neurotrophin 3/hippocampus-derived neurotrophic factor (NT3/ HDNF) (2-5) have revealed a family of neurotrophic proteins with a high degree of amino acid sequence homology to the well-known nerve growth factor (NGF) (6-9) and exhibiting somewhat overlapping yet distinct and characteristic patterns of distribution (10).In situ hybridization and RNA blot-hybridization (Northern blot) analyses from our laboratory and others indicate that the levels of mRNA for all members of the NGF family are relatively high in hippocampus (10, 11). However, BDNF mRNA appears to be more widespread in the brain than either NGF or NT3/HDNF, its distribution being highest in hippocampus, cortex, and other synaptic targets of basal forebrain cholinergic neurons (12)(13)(14). Although it has been reported recently that BDNF supports survival and differentiation of septal cholinergic neurons in vitro (15,16) and to some extent dopaminergic neurons in vitro (16,17), little is known regarding the localization, role, and neuronal specificity of BDNF in the central nervous system in vivo.In the present study, our goal was to obtain BDNF-specific antibodies, which do not cross-react with other NGF family (19,20). Sections (14 ,um) of freshly frozen brain were thawed onto poly(L-lysine)-coated slides and hybridized with specific and control probes for 16 hr at 42°C. Slides were dipped in Kodak NTB2 emulsion, diluted 1:1 in distilled water, and exposed for 6-8 weeks at -20°C.Peptide Synthesis and Immunization. Based upon computer-assisted analysis of the amino acid sequences for the NGF family, we have selected several regions within the BDNF protein having the lowest degree of sequence similarity to NGF and NT3/HDNF and lacking significant homology to other known proteins. Swissprot and National Biomedical Research Foundation protein data bases (release 26.0, September 1990) were searched by using the FASTA program and were analyzed for amino acid homology to peptides selected for use in this study (21). Secondary considerations were given to hydrophilicity (22) and predictions of antigenicity and secondary structure (24).On the basis of these criteria, decapeptide was synthesized with the carboxyl terminus in the unmodified acid form by automated, solid-phase methods (Microchemical Facility, Institute for Human Genetics, University of Minnesota) and was conjugated to bovine thyroglobulin in 0.8% glutaraldehyde (30 mg of peptide with 90 mg of carrier protein). The conjugate was dialyzed (Spectrapore dialysis tubing, molecular weight cutoffof 6,000-8,000) overnight at 4°C against 0.1 M phosphate-buffered saline (PBS) and diluted with PBS to 1 mg of peptide per ml. Six rabbits (New Zealand White; Estuna, Sweden) were immunize...

PKC ε Activation Prevents Synaptic Loss, Aβ Elevation, and Cognitive Deficits in Alzheimer's Disease Transgenic Mice

“…BDNF has been previously shown to be expressed in the cytoplasm and nuclei of CA1 cell bodies of pyramidal neurons (Wetmore et al, 1991;Wetmore and Olson, 1993;Nitta et al, 1997). Figure 6 A shows BDNF immunofluorescence in the cytoplasm and punctuate (or clumps) fluorescent particles in the nuclei of CA1 neurons; these results were also observed by others [Wetmore et al (1991), their Fig.…”

“…Figure 6 A shows BDNF immunofluorescence in the cytoplasm and punctuate (or clumps) fluorescent particles in the nuclei of CA1 neurons; these results were also observed by others [Wetmore et al (1991), their Fig. 3B].…”

Exercise reverses the harmful effects of consumption of a high-fat diet on synaptic and behavioral plasticity associated to the action of brain-derived neurotrophic factor

“…The expression of BDNF in the hippocampus is elevated by exercise (Neeper et al, 1995), in line with recent studies showing a clear involvement of BDNF with regulation of neuronal excitability (Kafitz et al, 1999;Bolton et al, 2000). BDNF is synthesized predominantly by neurons located in the hippocampus, a brain region intimately associated with the processing of cognitive function (Wetmore et al, 1991). BDNF facilitates synaptic transmission (Kang and Schuman, 1995;Levine et al, 1998;Sherwood and Lo, 1999;Tyler and Pozzo-Miller, 2001), and hippocampal BDNF seems necessary for the induction of long-term potentiation (Patterson et al, 1996;Linnarsson et al, 1997), a physiological correlate of learning.…”

“…BDNF is synthesized predominantly by neurons located in brain areas associated with the processing of cognitive functions, i.e. the hippocampus (Wetmore et al, 1991). Moreover, increases in hippocampal BDNF expression appear to be constitutive for the induction of long-term potentiation (LTP), a physiological correlate of learning (Patterson et al, 1992).…”

Post-Myocardial Infarction Depression

“…This distribution overlaps with immunohistochemical localization of BDNF itself in the rat cerebral cortex, hippocampus, basal forebrain, striatum, hypothalamus, cerebellum (Kawamoto et al 1996) as well as in the parietal and entorhinal cortices, amygdala and in the somatic nuclei (Wetmore et al 1991).…”