Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 18 de 18
Filter
Add more filters










Publication year range
1.
Front Aging Neurosci ; 9: 195, 2017.
Article in English | MEDLINE | ID: mdl-28676754

ABSTRACT

The neurological deterioration associated with Alzheimer's disease (AD), involving accumulation of amyloid-beta peptides and neurofibrillary tangles, is associated with evident neuroinflammation. This is now seen to be a significant contributor to pathology. Recently the tenet of the privileged status of the brain, regarding microbial compromise, has been questioned, particularly in terms of neurodegenerative diseases. It is now being considered that microbiological incursion into the central nervous system could be either an initiator or significant contributor to these. This is a novel study using 16S ribosomal gene-specific Next generation sequencing (NGS) of extracted brain tissue. A comparison was made of the bacterial species content of both frozen and formaldehyde fixed sections of a small cohort of Alzheimer-affected cases with those of cognitively unimpaired (normal). Our findings suggest an increase in bacterial populations in Alzheimer brain tissue compared with normal.

2.
Pharmacol Res ; 104: 97-107, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26687096

ABSTRACT

This study describes a fundamental functional difference between the two main polymorphisms of the pro-form of brain-derived neurotrophic factor (proBDNF), providing an explanation as to why these forms have such different age-related neurological outcomes. Healthy young carriers of the Met66 form (present in ∼30% Caucasians) have reduced hippocampal volume and impaired hippocampal-dependent memory function, yet the same polymorphic population shows enhanced cognitive recovery after traumatic brain injury, delayed cognitive dysfunction during aging, and lower risk of late-onset Alzheimer's disease (AD) compared to those with the more common Val66 polymorphism. To examine the differences between the protein polymorphisms in structure, kinetics of binding to proBDNF receptors and in vitro function, we generated purified cleavage-resistant human variants. Intriguingly, we found no statistical differences in those characteristics. As anticipated, exogenous application of proBDNF Val66 to rat hippocampal slices dysregulated synaptic plasticity, inhibiting long-term potentiation (LTP) and facilitating long-term depression (LTD). We subsequently observed that this occurred via the glycogen synthase kinase 3ß (GSK3ß) activation pathway. However, surprisingly, we found that Met66 had no such effects on either LTP or LTD. These novel findings suggest that, unlike Val66, the Met66 variant does not facilitate synapse weakening signaling, perhaps accounting for its protective effects with aging.


Subject(s)
Brain-Derived Neurotrophic Factor/genetics , Protein Precursors/genetics , Synapses/physiology , Animals , Brain-Derived Neurotrophic Factor/metabolism , Cells, Cultured , Glycogen Synthase Kinase 3 beta/metabolism , Hippocampus/drug effects , Hippocampus/physiology , Humans , L-Lactate Dehydrogenase/metabolism , Long-Term Potentiation/drug effects , Long-Term Potentiation/physiology , Male , Membrane Potential, Mitochondrial/drug effects , Mice , Neuronal Plasticity/drug effects , Neuronal Plasticity/physiology , Neurons/drug effects , Neurons/metabolism , Neurons/physiology , Polymorphism, Genetic , Protein Precursors/metabolism , Rats, Wistar , Recombinant Proteins/pharmacology , Synapses/drug effects , tau Proteins/metabolism
3.
J Med Chem ; 58(2): 767-77, 2015 Jan 22.
Article in English | MEDLINE | ID: mdl-25454499

ABSTRACT

The tyrosine kinase A (TrkA) receptor is a validated therapeutic intervention point for a wide range of conditions. TrkA activation by nerve growth factor (NGF) binding the second extracellular immunoglobulin (TrkAIg2) domain triggers intracellular signaling cascades. In the periphery, this promotes the pain phenotype and, in the brain, cell survival or differentiation. Reproducible structural information and detailed validation of protein-ligand interactions aid drug discovery. However, the isolated TrkAIg2 domain crystallizes as a ß-strand-swapped dimer in the absence of NGF, occluding the binding surface. Here we report the design and structural validation by nuclear magnetic resonance spectroscopy of the first stable, biologically active construct of the TrkAIg2 domain for binding site confirmation. Our structure closely mimics the wild-type fold of TrkAIg2 in complex with NGF ( 1WWW .pdb), and the (1)H-(15)N correlation spectra confirm that both NGF and a competing small molecule interact at the known binding interface in solution.


Subject(s)
Drug Discovery , Magnetic Resonance Spectroscopy/methods , Receptor, trkA/chemistry , Amitriptyline/metabolism , Binding Sites , Drug Design , Nerve Growth Factor/metabolism , Protein Structure, Tertiary , Receptor, trkA/metabolism , Recombinant Proteins , Structure-Activity Relationship
4.
J Alzheimers Dis ; 43(3): 725-38, 2015.
Article in English | MEDLINE | ID: mdl-25125469

ABSTRACT

This review, gathered from diverse sources, shows how our microbiome influences health and ultimately how well we age. Evidence linking oral bacteria to Alzheimer's disease (AD) is discussed in the context of aging, drawing together data from epidemiological, experimental, genetic, and environmental studies. Immunosenescence results in increased bacterial load as cell-mediated and humoral immune responses wane. The innate immune system gradually takes over; contributing to the rise in circulating proinflammatory cytokines such as TNFα. Maintaining the integrity of the blood-brain barrier (BBB) against a backdrop of increasing bacterial load is important. Aging may favor the proliferation of anaerobes in the mouth eliciting a robust TNFα response from the oral epithelium. Prolonged exposure to high levels of circulating TNFα compromises the integrity of the BBB. Sensitive techniques now detect the "asymptomatic" presence of bacteria in areas previously thought to be sterile, providing new insights into the wider distribution of components of the microbiome. These "immune-tolerated" bacteria may slowly multiply elsewhere until they elicit a chronic inflammatory response; some are now considered causal in instances of atherosclerosis and back pain. Inflammatory processes have long been associated with AD. We propose for a subset of AD patients, aging favors the overgrowth of oral anaerobes established earlier in life provoking a pro-inflammatory innate response that weakens the BBB allowing bacteria to spread and quietly influence the pathogenesis of AD. Finally, we suggest that human polymorphisms considered alongside components of the microbiome may provide new avenues of research for the prevention and treatment of disease.


Subject(s)
Aging/immunology , Alzheimer Disease/microbiology , Immunity, Innate , Microbiota , Mouth/microbiology , Alzheimer Disease/immunology , Alzheimer Disease/pathology , Humans , Immune System/pathology
5.
Stem Cell Res ; 11(3): 1206-21, 2013 Nov.
Article in English | MEDLINE | ID: mdl-24013066

ABSTRACT

Basal forebrain cholinergic neurons (bfCNs) which provide innervation to the hippocampus and cortex, are required for memory and learning, and are primarily affected in Alzheimer's Disease (AD), resulting in related cognitive decline. Therefore generation of a source of bfCNs from human pluripotent stem cells (hPSCs) is crucial for in vitro disease modeling and development of novel AD therapies. In addition, for the advancement of regenerative approaches there is a requirement for an accurate developmental model to study the neurogenesis and survival of this population. Here we demonstrate the efficient production of bfCNs, using a novel embryoid body (EB) based non-adherent differentiation (NAdD) protocol. We establish a specific basal forebrain neural stem cell (NSC) phenotype via expression of the basal forebrain transcription factors NKX2.1 and LHX8, as well as the general forebrain marker FOXG1. We present evidence that this lineage is achieved via recapitulation of embryonic events, with induction of intrinsic hedgehog signaling, through the use of a 3D non-adherent differentiation system. This is the first example of hPSC-derived basal forebrain-like NSCs, which are scalable via self-renewal in prolonged culture. Furthermore upon terminal differentiation these basal forebrain-like NSCs generate high numbers of cholinergic neurons expressing the specific markers ChAT, VACht and ISL1. These hPSC-derived bfCNs possess characteristics that are crucial in a model to study AD related cholinergic neuronal loss in the basal forebrain. Examples are expression of the therapeutic target p75(NTR), the release of acetylcholine, and demonstration of a mature, and functional electrophysiological profile. In conclusion, this work provides a renewable source of human functional bfCNs applicable for studying AD specifically in the cholinergic system, and also provides a model of the key embryonic events in human bfCN development.


Subject(s)
Cell Differentiation , Cholinergic Neurons/cytology , Hedgehog Proteins/metabolism , Pluripotent Stem Cells/cytology , Prosencephalon/cytology , Signal Transduction , Acetylcholinesterase/metabolism , Animals , Brain/metabolism , Brain/pathology , Calcium/metabolism , Cell Line , Cell Lineage , Cholinergic Neurons/metabolism , Cholinergic Neurons/transplantation , Female , Humans , Pluripotent Stem Cells/metabolism , Rats , Rats, Inbred Lew , Transplantation, Heterologous
6.
J Comput Aided Mol Des ; 27(4): 365-72, 2013 Apr.
Article in English | MEDLINE | ID: mdl-23625024

ABSTRACT

Aberrant transforming growth factor-ß (TGF-ß) signalling has been associated with a number of disease pathologies, such as the development of fibrosis in the heart, lung and liver, cardiovascular disease and cancer, hence the TGF-ß pathway represents a promising target for a variety of diseases. However, highly specific ways to inhibit TGF-ß signalling need to be developed to prevent cross-talk with related receptors and minimise unwanted side effects. We have used used virtual screening and molecular docking to identify small molecule inhibitors of TGF-ß binding to TßRII. The crystal structure of TGF-ß3 in complex with the extracellular domain of the type II TGF-ß receptor was taken as a starting point for molecular docking and we developed a structure-based pharmacophore model to identify compounds that competitively inhibit the binding of TGF-ß to TßRII and antogonize TGF-ß signalling. We have experimentally tested 67 molecules suggested by in silico screening and similarity searching for their ability to inhibit TGF-ß signalling in TGF-ß-dependent luciferase assays in vitro and the molecule with the strongest inhibition had an IC50 of 18 µM. These compounds were selected to bind to the SS1 subsite (composed of F30, C31, D32, I50, T51 S52, I53, C54 and E55) of TßRII and all share the general property of being aromatic and fairly flat. Molecular dynamics simulations confirmed that this was the most likely binding mode. The computational methods used and the hits identified in this study provide an excellent guide to medicinal chemistry efforts to design tighter binding molecules to disrupt the TGF-ß/TßRII interaction.


Subject(s)
Drug Design , Small Molecule Libraries/chemistry , Small Molecule Libraries/pharmacology , Transforming Growth Factor beta3/antagonists & inhibitors , Transforming Growth Factor beta3/metabolism , Humans , Molecular Docking Simulation , Molecular Dynamics Simulation , Protein Binding/drug effects , Protein Interaction Maps/drug effects , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/metabolism , Receptor, Transforming Growth Factor-beta Type II , Receptors, Transforming Growth Factor beta/antagonists & inhibitors , Receptors, Transforming Growth Factor beta/metabolism , Signal Transduction/drug effects , Transforming Growth Factor beta3/chemistry
7.
Pharmacol Ther ; 138(2): 155-75, 2013 May.
Article in English | MEDLINE | ID: mdl-23348013

ABSTRACT

Glial cell-derived neurotrophic factor (GDNF), and the neurotrophin nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are important for the survival, maintenance and regeneration of specific neuronal populations in the adult brain. Depletion of these neurotrophic factors has been linked with disease pathology and symptoms, and replacement strategies are considered as potential therapeutics for neurodegenerative diseases such as Parkinson's, Alzheimer's and Huntington's diseases. GDNF administration has recently been shown to be an effective treatment for Parkinson's disease, with clinical trials currently in progress. Trials with NGF for Alzheimer's disease are ongoing, with some degree of success. Preclinical results using BDNF also show much promise, although there are accompanying difficulties. Ultimately, the administration of a therapy involving proteins in the brain has inherent problems. Because of the blood-brain-barrier, the protein must be infused directly, produced by viral constructs, secreted from implanted protein-secreting cells or actively transported across the brain. An alternative to this is the use of a small molecule agonist, a modulator or enhancer targeting the associated receptors. We evaluate these neurotrophic factors as potential short or long-term treatments, weighing up preclinical and clinical results with the possible effects on the underlying neurodegenerative process.


Subject(s)
Nerve Growth Factors/therapeutic use , Neurodegenerative Diseases/drug therapy , Animals , Brain-Derived Neurotrophic Factor/administration & dosage , Brain-Derived Neurotrophic Factor/chemistry , Brain-Derived Neurotrophic Factor/metabolism , Brain-Derived Neurotrophic Factor/therapeutic use , Glial Cell Line-Derived Neurotrophic Factor/administration & dosage , Glial Cell Line-Derived Neurotrophic Factor/chemistry , Glial Cell Line-Derived Neurotrophic Factor/metabolism , Glial Cell Line-Derived Neurotrophic Factor/therapeutic use , Humans , Ligands , Models, Molecular , Nerve Growth Factors/administration & dosage , Nerve Growth Factors/chemistry , Nerve Growth Factors/metabolism , Neurodegenerative Diseases/metabolism
8.
Curr Neuropharmacol ; 9(4): 559-73, 2011 Dec.
Article in English | MEDLINE | ID: mdl-22654716

ABSTRACT

Besides being essential for correct development of the vertebrate nervous system the neurotrophins also play a vital role in adult neuron survival, maintenance and regeneration. In addition they are implicated in the pathogenesis of certain neurodegenerative diseases, and may even provide a therapeutic solution for some. In particular there have been a number of studies on the involvement of nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) in the development of Alzheimer's disease. This disease is of growing concern as longevity increases worldwide, with little treatment available at the moment to alleviate the condition. Memory loss is one of the earliest symptoms associated with Alzheimer's disease. The brain regions first affected by pathology include the hippocampus, and also the entorhinal cortex and basal cholinergic nuclei which project to the hippocampus; importantly, all these areas are required for memory formation. Both NGF and BDNF are affected early in the disease and this is thought to initiate a cascade of events which exacerbates pathology and leads to the symptoms of dementia. This review briefly describes the pathology, symptoms and molecular processes associated with Alzheimer's disease; it discusses the involvement of the neurotrophins, particularly NGF and BDNF, and their receptors, with changes in BDNF considered particularly in the light of its importance in synaptic plasticity. In addition, the possibilities of neurotrophin-based therapeutics are evaluated.

9.
Pain ; 149(2): 386-392, 2010 May.
Article in English | MEDLINE | ID: mdl-20350782

ABSTRACT

The origin of pain in osteoarthritis is poorly understood, but it is generally thought to arise from inflammation within the innervated structures of the joint, such as the synovium, capsule and bone. We investigated the role of nerve growth factor (NGF) in pain development in murine OA, and the analgesic efficacy of the soluble NGF receptor, TrkAD5. OA was induced in mice by destabilisation of the medial meniscus and pain was assessed by measuring hind-limb weight distribution. RNA was extracted from joints, and NGF and TNF expressions were quantified. The effect of tumour necrosis factor (TNF) and neutrophil blockade on NGF expression and pain were also assessed. NGF was induced in the joints during both post-operative (day 3) and OA (16weeks) pain, but not in the non-painful stage of disease (8weeks post-surgery). TrkAd5 was highly effective at suppressing pain in both phases. Induction of NGF in the post-operative phase of pain was TNF-dependent as anti-TNF reduced NGF expression in the joint and abrogated pain. However, TNF was not regulated in the late OA joints, and pain was not affected by anti-TNF therapy. Fucoidan, by suppressing cellular infiltration into the joint, was able to suppress post-operative, but not late OA pain. These results indicate that NGF is an important mediator of OA pain and that TrkAd5 represents a potent novel analgesic in this condition. They also suggest that, unlike post-operative pain, induction of pain in OA may not necessarily be driven by classical inflammatory processes.


Subject(s)
Analgesics/pharmacology , Arthralgia/drug therapy , Nerve Growth Factor/agonists , Osteoarthritis, Knee/drug therapy , Peptide Fragments/pharmacology , Peptides/pharmacology , Receptor, trkA/therapeutic use , Analgesics/chemical synthesis , Animals , Arthralgia/metabolism , Arthralgia/physiopathology , Disease Models, Animal , Etanercept , Immunoglobulin G/pharmacology , Immunoglobulin G/therapeutic use , Knee Joint/drug effects , Knee Joint/innervation , Knee Joint/physiopathology , Male , Mice , Mice, Inbred C57BL , Nerve Growth Factor/metabolism , Neutrophils/drug effects , Neutrophils/metabolism , Osteoarthritis, Knee/metabolism , Osteoarthritis, Knee/physiopathology , Pain Measurement/methods , Peptide Fragments/chemical synthesis , Peptides/chemical synthesis , Polysaccharides/pharmacology , Receptors, Tumor Necrosis Factor/therapeutic use , Treatment Outcome , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Tumor Necrosis Factor-alpha/metabolism
10.
J Biol Chem ; 284(27): 18424-33, 2009 Jul 03.
Article in English | MEDLINE | ID: mdl-19389705

ABSTRACT

Nerve growth factor (NGF) is produced as a precursor called pro-nerve growth factor (proNGF), which is secreted by many tissues and is the predominant form of NGF in the central nervous system. In Alzheimer disease brain, cholinergic neurons degenerate and can no longer transport NGF as efficiently, leading to an increase in untransported NGF in the target tissue. The protein that accumulates in the target tissue is proNGF, not the mature form. The role of this precursor is controversial, and both neurotrophic and apoptotic activities have been reported for recombinant proNGFs. Differences in the protein structures, protein expression systems, methods used for protein purification, and methods used for bioassay may affect the activity of these proteins. Here, we show that proNGF is neurotrophic regardless of mutations or tags, and no matter how it is purified or in which system it is expressed. However, although proNGF is neurotrophic under our assay conditions for primary sympathetic neurons and for pheochromocytoma (PC12) cells, it is apoptotic for unprimed PC12 cells when they are deprived of serum. The ratio of tropomyosin-related kinase A to p75 neurotrophin receptor is low in unprimed PC12 cells compared with primed PC12 cells and sympathetic neurons, altering the balance of proNGF-induced signaling to favor apoptosis. We conclude that the relative level of proNGF receptors determines whether this precursor exhibits neurotrophic or apoptotic activity.


Subject(s)
Nerve Growth Factor/metabolism , Neurons/physiology , Protein Precursors/metabolism , Receptor, Nerve Growth Factor/metabolism , Receptor, trkA/metabolism , Animals , Apoptosis/physiology , Baculoviridae/genetics , Culture Media, Serum-Free/pharmacology , Escherichia coli/genetics , Gene Expression/physiology , Humans , Kidney/cytology , Mice , Mitogen-Activated Protein Kinases/metabolism , Nerve Growth Factor/genetics , Neurites/physiology , Neurons/ultrastructure , PC12 Cells , Phosphorylation/physiology , Protein Precursors/genetics , Rats , Spodoptera , Sympathetic Nervous System/cytology
11.
BioDrugs ; 22(6): 349-59, 2008.
Article in English | MEDLINE | ID: mdl-18998753

ABSTRACT

Chronic pain presents a huge economic and social burden, with existing treatments largely unable to satisfy medical needs. Recently, studies have shown that nerve growth factor (NGF) is a major mediator of inflammatory and neuropathic pain, providing a new therapeutic target. Although originally discovered as a trophic factor for sympathetic and sensory neurons during development, it now appears that in adults, levels of NGF are elevated in many acute and chronic pain conditions. Furthermore, preclinical animal models of inflammatory and neuropathic pain also show increased NGF levels, while the sequestration of NGF alleviates the associated hyperalgesia. The molecular mechanisms involved are being elucidated. This review briefly examines pain signaling pathways and describes currently available analgesics. It then investigates the approaches taken in targeting NGF-mediated pain. Current options being explored include the development of humanized monoclonal antibodies to NGF or its tyrosine kinase receptor TrkA (also known as neurotrophic tyrosine kinase receptor, type 1 [NTRK1]), and the sequestration of NGF using TrkA domain 5 (TrkAd5), a soluble receptor protein that binds NGF with picomolar affinity. Administration of either antibodies or TrkAd5 has been shown to be effective in a number of preclinical models of pain, including cystitis, osteoarthritis, UV irradiation (sunburn), and skeletal bone pain due to fracture or cancer. Other possible future therapies examined in this review include small-molecule TrkA antagonists, which target either the extracellular NGF binding domain of TrkA or its intracellular tyrosine kinase domain.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Nerve Growth Factor/antagonists & inhibitors , Pain Management , Analgesics/therapeutic use , Animals , Humans , Nerve Growth Factor/immunology , Nerve Growth Factor/physiology , Pain/physiopathology , Peptides/therapeutic use , Receptor, trkA/antagonists & inhibitors , Receptor, trkA/chemistry , Receptor, trkA/immunology , Receptor, trkA/physiology , Recombinant Proteins , Signal Transduction/drug effects , Signal Transduction/physiology
12.
J Neurochem ; 107(4): 1124-35, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18808449

ABSTRACT

Nerve growth factor (NGF) promotes cell survival via binding to the tyrosine kinase receptor A (TrkA). Its precursor, proNGF, binds to p75(NTR) and sortilin receptors to initiate apoptosis. Current disagreement exists over whether proNGF acts neurotrophically following binding to TrkA. As in Alzheimer's disease the levels of proNGF increase and TrkA decrease, it is important to clarify the properties of proNGF. Here, wild-type and cleavage-resistant mutated forms (M) of proNGF were engineered and their binding characteristics determined. M-proNGF and NGF bound to p75(NTR) with similar affinities, whilst M-proNGF had a lower affinity than NGF for TrkA. M-proNGF behaved neurotrophically, albeit less effectively than NGF. M-proNGF addition resulted in phosphorylation of TrkA and ERK1/2, and in PC12 cells elicited neurite outgrowth and supported cell survival. Conversely, M-proNGF addition to cultured cortical neurons initiated caspase 3 cleavage. Importantly, these biological effects were shown to be mediated by unprocessed M-proNGF. Surprisingly, binding of the pro region alone to TrkA, at a site other than that of NGF, caused TrkA and ERK1/2 phosphorylation. Our data show that M-proNGF stimulates TrkA to a lesser degree than NGF, suggesting that in Alzheimer brain the increased proNGF : NGF and p75(NTR) : TrkA ratios may permit apoptotic effects to predominate over neurotrophic effects.


Subject(s)
Adaptor Proteins, Vesicular Transport/metabolism , Nerve Growth Factor/metabolism , Neurons/metabolism , Protein Precursors/metabolism , Receptor, trkA/metabolism , Receptors, Nerve Growth Factor/metabolism , Animals , Animals, Newborn , Caspase 3/metabolism , Cell Survival , Cells, Cultured , Cerebral Cortex/cytology , Humans , Mitogen-Activated Protein Kinase 3/metabolism , Mutation/physiology , Nerve Growth Factor/genetics , Nerve Tissue Proteins , Neurites/metabolism , Neurons/drug effects , Phosphorylation , Protein Binding , Protein Precursors/genetics , Radioligand Assay/methods , Rats , Receptors, Growth Factor , Recombinant Proteins , Signal Transduction/physiology , Time Factors
13.
Clin Sci (Lond) ; 110(2): 175-91, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16411894

ABSTRACT

The neurotrophins are growth factors required by discrete neuronal cell types for survival and maintenance, with a broad range of activities in the central and peripheral nervous system in the developing and adult mammal. This review examines their role in diverse disease states, including Alzheimer's disease, depression, pain and asthma. In addition, the role of BDNF (brain-derived neurotrophic factor) in synaptic plasticity and memory formation is discussed. Unlike the other neurotrophins, BDNF is secreted in an activity-dependent manner that allows the highly controlled release required for synaptic regulation. Evidence is discussed which shows that sequestration of NGF (nerve growth factor) is able to reverse symptoms of inflammatory pain and asthma in animal models. Both pain and asthma show an underlying pathophysiology linked to increases in endogenous NGF and subsequent NGF-dependent increase in BDNF. Conversely, in Alzheimer's disease, there is a role for NGF in the treatment of the disease and a recent clinical trial has shown benefit from its exogenous application. In addition, reductions in BDNF, and changes in the processing and usage of NGF, are evident and it is possible that both NGF and BDNF play a part in the aetiology of the disease process. This highly selective choice of functions and disease states related to neurotrophin function, although in no way comprehensive, illustrates the importance of the neurotrophins in the brain, the peripheral nervous system and in non-neuronal tissues. Ways in which the neurotrophins, their receptors or agonists/antagonists may act therapeutically are discussed.


Subject(s)
Nerve Growth Factors/metabolism , Neurons/metabolism , Peripheral Nervous System/physiology , Receptors, Nerve Growth Factor/metabolism , Alzheimer Disease/metabolism , Amyloidosis/metabolism , Asthma/metabolism , Brain Diseases/metabolism , Depression/metabolism , Humans , Nerve Growth Factors/therapeutic use , Neuronal Plasticity , Synaptic Transmission
14.
Neurobiol Aging ; 27(6): 797-803, 2006 Jun.
Article in English | MEDLINE | ID: mdl-15979210

ABSTRACT

APOE affects the risk of Alzheimer's disease (AD) and course of several other neurologic diseases. Experimental studies suggest that APOE influences synaptogenesis. We measured the concentration of two presynaptic proteins, synaptophysin and syntaxin 1, and also postsynaptic density-95 (PSD95), in superior temporal cortex from 42 AD and 160 normal brains, and determined the APOE genotypes. The concentration of both presynaptic proteins was approximately two-thirds lower in AD than normal brains and that of PSD95 one-third lower. No effect of APOE on synaptic proteins was found in advanced AD. However, in normal brain, epsilon4 was associated with lower concentrations of all three synaptic proteins and epsilon2 with significantly elevated PSD95 (p=0.03). A combined measure of synaptic proteins showed a significant linear decrease from epsilon2 through epsilon3 to varepsilon4 (p=0.01). APOE influences the concentration of synaptic proteins in normal superior temporal cortex and may thereby affect the response to injury, and the risk and outcome of a range of neurologic diseases.


Subject(s)
Alzheimer Disease/genetics , Alzheimer Disease/metabolism , Apolipoproteins E/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Membrane Proteins/metabolism , Synaptophysin/metabolism , Temporal Lobe/metabolism , Adult , Aged , Aged, 80 and over , Alzheimer Disease/pathology , Confidence Intervals , Disks Large Homolog 4 Protein , Enzyme-Linked Immunosorbent Assay/methods , Female , Humans , Male , Middle Aged , Postmortem Changes , Qa-SNARE Proteins/metabolism
15.
J Pharmacol Exp Ther ; 316(3): 1122-9, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16284276

ABSTRACT

Elevated levels of nerve growth factor have been linked to the onset and persistence of many pain-related disorders and asthma. Described here are the design, expression, refolding, and purification of a monomeric (nonstrand-swapped) form of the binding domain of the nerve growth factor receptor, designated TrkAd5. We have shown that TrkAd5 produced recombinantly binds nerve growth factor with picomolar affinity. TrkAd5 has been characterized using a variety of biophysical and biochemical assays and is shown here to be stable in both plasma and urine. The palliative effects of TrkAd5 are demonstrated in animal models of inflammatory pain and allergic asthma. We conclude that TrkAd5 will prove effective in ameliorating both acute and chronic conditions where nerve growth factor acts as a mediator and suggest a role for its application in vivo as a novel therapeutic.


Subject(s)
Asthma/drug therapy , Cystitis/drug therapy , Pain/drug therapy , Peptides/therapeutic use , Receptor, trkA/therapeutic use , Amino Acid Sequence , Animals , Binding Sites , Drug Stability , Female , Freeze Drying , Guinea Pigs , Male , Nerve Growth Factor/pharmacology , PC12 Cells , Peptides/chemistry , Protein Folding , Protein Structure, Tertiary , Rats , Rats, Wistar , Receptor, trkA/chemistry , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Trachea/drug effects
16.
J Urol ; 173(3): 1016-21, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15711368

ABSTRACT

PURPOSE: Studies suggest that nerve growth factor (NGF) contributes to bladder overactivity stemming from bladder inflammation. Studies were performed to determine the NGF dependence of cyclophosphamide (CYP) induced changes in bladder function using the recombinant NGF sequestering protein REN1820. MATERIALS AND METHODS: Urodynamic testing and behavioral observations were made in female rats treated with CYP (4 or 48 hours) and REN1820 or vehicle. RESULTS: Rats examined 4 or 48 hours after CYP treatment plus REN1820 showed significantly fewer nonvoiding contractions with smaller amplitude (p

Subject(s)
Cystitis/drug therapy , Cystitis/physiopathology , Receptor, trkA/therapeutic use , Animals , Cyclophosphamide/administration & dosage , Cystitis/chemically induced , Female , Rats , Rats, Wistar , Recombinant Proteins , Time Factors
17.
Biochem Biophys Res Commun ; 299(3): 373-6, 2002 Dec 06.
Article in English | MEDLINE | ID: mdl-12445809

ABSTRACT

The amyloid plaque, a neuropathological hallmark of Alzheimer's disease, is produced by the deposition of beta-amyloid (Abeta) peptide, which is cleaved from Amyloid Precursor Protein (APP) by the enzyme beta-secretase. Only small amounts of Abeta form in normal brain; more typically this is precluded by the processing of APP by alpha-secretase. Here, we describe a decrease in alpha-secretase (81% of normal) and a large increase in beta-secretase activity (185%) in sporadic Alzheimer's disease temporal cortex. Since alpha-secretase is present principally in neurons known to be vulnerable in Alzheimer's disease, and there is known competition between alpha- and beta-secretase for the substrate APP, it is significant that the majority of Alzheimer samples tested here were low in alpha-secretase. Eighty percent of Alzheimer brains examined had an increase in beta-secretase, a decrease in alpha-secretase, or both; which may account for the means by which the majority of people develop Alzheimer's disease.


Subject(s)
Alzheimer Disease/metabolism , Amyloid beta-Protein Precursor/metabolism , Aspartic Acid Endopeptidases/metabolism , Endopeptidases/metabolism , Temporal Lobe/enzymology , Aged , Aged, 80 and over , Alzheimer Disease/physiopathology , Amyloid Precursor Protein Secretases , Apolipoproteins E/genetics , Choline O-Acetyltransferase/metabolism , Humans , Statistics as Topic
18.
Biochem Biophys Res Commun ; 291(3): 501-7, 2002 Mar 01.
Article in English | MEDLINE | ID: mdl-11855816

ABSTRACT

TrkB is a member of the Trk family of tyrosine kinase receptors. In vivo, the extracellular region of TrkB is known to bind, with high affinity, the neurotrophin protein brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT-4). We describe the expression and purification of the second Ig-like domain of human TrkB (TrkBIg(2)) and show, using surface plasmon resonance, that this domain is sufficient to bind BDNF and NT-4 with subnanomolar affinity. BDNF and NT-4 may have therapeutic implications for a variety of neurodegenerative diseases. The specificity of binding of the neurotrophins to their receptor TrkB is therefore of interest. We examine the specificity of TrkBIg(2) for all the neurotrophins, and use our molecular model of the BDNF-TrkBIg(2) complex to examine the residues involved in binding. It is hoped that the understanding of specific interactions will allow design of small molecule neurotrophin mimetics.


Subject(s)
Brain-Derived Neurotrophic Factor/metabolism , Nerve Growth Factors/metabolism , Receptor, trkB/chemistry , Receptor, trkB/metabolism , Amino Acid Sequence , Binding Sites , Circular Dichroism , Humans , Immunoglobulin Fragments/chemistry , Kinetics , Models, Molecular , Molecular Sequence Data , Protein Structure, Tertiary , Receptor, trkB/isolation & purification , Sequence Homology, Amino Acid , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Surface Plasmon Resonance
SELECTION OF CITATIONS
SEARCH DETAIL
...