Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0002736 (amyotrophic lateral sclerosis)
 19,048 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The death of motor neurons in amyotrophic lateral sclerosis (ALS) is thought to result from the interaction of a variety of factors including excitotoxicity, accumulation of toxic proteins, and abnormal axonal transport. Previously, we found that the susceptibility of motor neurons to excitotoxic insults can be limited by inhibiting signals evoked by brain-derived neurotrophic factor (BDNF) activation of the receptor tyrosine kinase B (TrkB). Here we show that this can be achieved by direct kinase inhibition or by blockade of a transactivation pathway that uses adenosine A2a receptors and src-family kinases (SFKs). Downstream signaling cascades (such as mitogen-activated protein kinase and phosphatidylinositol-3 kinase) are inhibited by these blockers. In addition to protecting motor neurons from excitotoxic insult, these agents also prevent toxicity that follows from the expression of mutant proteins (G85R superoxide dismutase 1; G59S p150(glued)) that cause familial motor neuron disease. TrkB, adenosine A2a receptors, and SFKs associate into complexes in lipid raft and nonlipid raft membranes and the signaling from lipids rafts may be particularly important because their disruption by cholesterol depletion blocks the ability of BDNF to render motor neurons vulnerable to insult. The neuroprotective versatility of Trk antagonism suggests that it may have broad utility in the treatment of ALS patients.
 ...
PMID:Protecting motor neurons from toxic insult by antagonism of adenosine A2a and Trk receptors. 1695 81

Corticospinal motor neurons (CSMN) are among the most complex CNS neurons; they control voluntary motor function and are prototypical projection neurons. In amyotrophic lateral sclerosis (ALS), both spinal motor neurons and CSMN degenerate; their damage contributes centrally to the loss of motor function in spinal cord injury. Direct investigation of CSMN is severely limited by inaccessibility in the heterogeneous cortex. Here, using new CSMN purification and culture approaches, and in vivo analyses, we report that insulin-like growth factor-1 (IGF-I) specifically enhances the extent and rate of murine CSMN axon outgrowth, mediated via the IGF-I receptor and downstream signaling pathways; this is distinct from IGF-I support of neuronal survival. In contrast, brain-derived neurotrophic factor (BDNF) enhances branching and arborization, but not axon outgrowth. These experiments define specific controls over directed differentiation of CSMN, indicate a distinct role of IGF-I in CSMN axon outgrowth during development, and might enable control over CSMN derived from neural precursors.
 ...
PMID:IGF-I specifically enhances axon outgrowth of corticospinal motor neurons. 1706 65

Growth factors and their respective receptors are key regulators during development and for homeostasis of the nervous system. In addition, changes in growth factor function, availability or downstream signaling is involved in many neuropathological disorders like Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis, stroke and brain tumours. Research of the recent years revealed that some growth factors, initially discovered as neural growth factors are also affecting blood vessels [e.g. nerve growth factor (NGF) or brain-derived neurotrophic factor (BDNF)]. Likewise, vascular growth factors, such as vascular endothelial growth factor (VEGF), which was previously described as an endothelial cell specific mitogen, also affect neural cells. The discovery of shared growth factors affecting the vascular and the nervous system is of relevance for potential therapies of vascular and neurological diseases. This review aims to give an overview about the growing field of common growth factors and receptors within the two different networks.
 ...
PMID:Different networks, common growth factors: shared growth factors and receptors of the vascular and the nervous system. 1749 93

Nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) belong to the protein family of neurotrophins. They both display profound neuromodulatory functions and are essentially involved in the survival and homeostatic maintenance of central and peripheral neurons during development and adulthood. Moreover, NGF and BDNF are known to modulate immune cell function and thus serve as mediators in the reciprocal cross talk between neurons and immune cells. Neurotrophic factors have been implicated in pathophysiological mechanisms of many diseases of the nervous and the immune system, such as amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), neuropathy, pain, allergic bronchial asthma (BA) and neurotrophic keratitis. For all these diseases research has reached the point of creating strategies for therapeutic intervention with neurotrophins. In this review, we present an overview of the pathophysiology, therapeutic interventions and strategies concerning NGF and BDNF in the mentioned diseases.
 ...
PMID:Neurotrophic factors--a tool for therapeutic strategies in neurological, neuropsychiatric and neuroimmunological diseases? 1789 80

Neurotrophic factors comprise a broad family of secreted proteins that have growth promoting, survival promoting and differentiation inducing activities. Disruption of neurotrophic factor signalling is a characteristic of many central and peripheral nervous system disorders, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, stroke, and peripheral neuropathy and pain. It follows that treating patients with neurotrophic factors might be beneficial in a range of neurological diseases. However, the promising results seen in animal models of disease have not translated well into clinical trials due to the poor pharmacokinetics associated with the intact proteins, in particular, their short in vivo half-life, low blood brain barrier permeability, limited diffusion, and undesirable effects through multiple receptor interactions. This has been the main motivation for the design of small molecule modulators of the neurotrophic factor pathways. The review gives a brief survey of the various strategies to design mimetics that have been reported in the literature with special emphasis on the tandem repeat peptide agonist approach for BDNF/NT-4/5 and N-cadherin mimetics.
 ...
PMID:Tandem repeat peptide strategy for the design of neurotrophic factor mimetics. 1828 37

AIT-082 (an analog of hypoxanthine) is an orally-active nerve growth factor (NGF) agonist under development by NeoTherapeutics as a potential treatment for Alzheimer's disease (AD), stroke and motor neuron disease. A phase II safety and efficacy trial in AD, originally scheduled to begin in the summer of 1997 [283677], began in May 1998 [286975,285562]. The study will enroll more than 60 AD patients [286975]. In February 1998, NeoTherapeutics began a phase I multiple-dose pharmacokinetic study of AIT-082 in 24 healthy elderly volunteers. Subjects of the phase I study will be administered AIT-082 once a day for 7 consecutive days at doses of 100 to 2000 mg per dose [279422]. A limited double-blind, placebo-controlled phase I/II trial in 10 AD patients commenced in Canada in the first quarter of 1997. Treatment with 4000 mg improved memory in 60% of the patients within 3 h, as determined by the word recall test. A decrease in memory was observed in 80% of placebo-treated patients [257132]. A phase I US trial, conducted by the Alzheimer's Disease Cooperative Study, with funding from the National Institute of Aging, began in July 1997. AIT-082 was administered to eight healthy, elderly volunteers as part of an escalating single-dose study. Oral administration of AIT-082 was well-tolerated at high doses [284325] AIT-082 also enhanced memory function in both young adult and aged mice within 2 h of oral administration. Prophylactic treatment prevented or delayed the onset of age-induced memory deficits in mice when administered in drinking water. When memory impairment was produced by brain lesions, the drug restored memory performance and increased the genetic expression of neurotrophin-3 (NT-3), a natural protein growth factor associated with nerve cell function [284325]. AIT-082 appears to have at least three effects on the growth of PC-12 cells in culture. Firstly, it stimulates outgrowth of neurites, secondly it potentiates the growth effects of neurotrophin, and thirdly, it stimulates the synthesis of certain neurotrophins (nerve growth factor, neurotrophin-3 and fibroblast growth factor) and pleiotrophins by astrocytes. These progrowth mechanisms are thought to form the basis of the ability of AIT-082 to restore and prevent age-related working memory deficits in mice [195438]. In October 1997, further preclinical results were presented, demonstrating that treatment with AIT-082 produced an increase in neurotrophic factors following spinal cord injury in rats. This study was conducted at NeoTherapeutics and McMaster University, and was partially funded by the Amyotrophic Lateral Sclerosis Society of Canada. After 7 days of treatment, rats with spinal cord injuries showed an increase in the levels of CNTF and BDNF, naturally occurring growth factors in the spinal cord [267514].
 ...
PMID:AIT-082 NeoTherapeutics Inc. 1846 24

Nerve growth factor (NGF) binds to TrkA receptors (neurotrophic) and P75(NTR) (apoptosis or other pathways depending on the coupled adaptor proteins). Brain derived growth factor (BDNF) can bind to TrkB (neurotrophic) and P75(NTR) receptors. BDNF is the main, activity-dependent, neurotrophin and sculpts neuronal organisation dependent on activity, thereby coupling and balancing effects on excitatory (glutamate) and inhibitory (GABA) transmission--in a synapse-specific manner. Some drugs can interact in a specific way. Positive modulators of AMPA receptors induce BDNF and favour long term potentiation (LTP) and memory processes. Some antidepressants such as tianeptine reverse stress-induced inhibition of LTP and restore neuronal plasticity in brain areas at risk. Inflammatory cytokines are produced in sickness behaviour mimicking depression. Interleukin (IL)1beta can exacerbate the immediate effects of stressors, and enhance and prolong the overall effects, which may be protective in preventing overuse or by increasing conservation-withdrawal: in some synapses IL1beta induces long term depression (LTD) or blocks LTP. The interactions with neurotrophins are complex and frequently reciprocal. However, NGF also contributes to inflammatory situations and mediates pain responses. This interplay is poorly understood but may be critical in cerebral palsy, neurodegenerative disorders such as amyotrophic lateral sclerosis and multiple sclerosis, and even Alzheimer's disease.
 ...
PMID:Neurotrophins and cytokines in neuronal plasticity. 1849 6

Amyotrophic lateral sclerosis (ALS) is a progressive motoneuron disease, whose pathogenesis remains unclear. Phorbol 12-myristate 13-acetate (PMA) has been shown to be neurotrophic and neuroprotective in several types of neurons in culture. However, the survival effect of PMA on motoneurons has not been reported. Therefore, we investigated this using purified rat motoneurons. PMA showed a small but significant neurotrophic activity, which was inhibited by GF109203X, a protein kinase C (PKC) inhibitor. Under the conditions in which the survival of motoneurons is supported by brain-derived neurotrophic factor (BDNF), excitotoxicity was induced by glutamate. PMA markedly protected motoneurons against excitotoxicity. The up-regulation of PKC in the spinal cord of ALS patients was previously reported, therefore, the present results indicate that PKC activation might be involved in neuroprotection.
 ...
PMID:Protein kinase C-mediated protection of motoneurons from excitotoxicity. 1851 17

Amyotrophic lateral sclerosis is a debilitating disease that results from the deterioration and loss of motor neurons. The neurotoxic potential of Zn(2+), both in vitro and in vivo, has been well established; however, the mechanism(s) of zinc's toxicity remain unclear. Our laboratory has demonstrated that Zn(2+)-mediated inhibition of neurotrophins can induce cell death. The present study investigates the neurotoxic mechanism(s) of this metal ion by assessing zinc's selectivity in altering the neurotrophin BDNF, but not the neural cytokine CNTF, with respect to motor neuron survival. Embryonic day 15 rat spinal motor neuron cultures were maintained in either BDNF or CNTF. Terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) staining showed that exposure to 100microM Zn(2+) significantly increased the number of pro-apoptotic neurons in cultures maintained with BDNF, while these conditions had no effect on cultures maintained with CNTF. We also demonstrate that BDNF protomer cross-linking efficiency and TrkB receptor cross-linking to BDNF are significantly inhibited by Zn(2+), suggesting that a Zn(2+)-induced change in BDNF conformation inhibits receptor-binding activity. This study reveals a mechanism by which zinc toxicity is mediated via a selective loss in neurotrophin activity resulting in motor neuron death.
 ...
PMID:Zinc induces motor neuron death via a selective inhibition of brain-derived neurotrophic factor activity. 1857 58

Pituitary adenylate cyclase-activating polypeptide (PACAP) has been shown to be neurotrophic or neuroprotective in various neurons in culture. It is expressed in spinal motoneurons in vivo and its expression is increased markedly after axotomy, suggesting a neuroprotective role via an autocrine mechanism. However, neurotrophic activity of PACAP has not been reported for motoneurons. In the present study, we investigated the effects of PACAP on rat motoneurons in culture. In the presence of a phosphodiesterase inhibitor, PACAP showed significant neurotrophic activity at concentrations as low as 0.01 nM. Previously, we found that glutamate was excitotoxic to motoneurons even in the presence of brain-derived neurotrophic factor, which is neurotrophic for motoneurons. PACAP with a phosphodiesterase inhibitor protected motoneurons against this excitotoxicity. The activity of PACAP was inhibited by the protein kinase A inhibitor N-[2-(p-bromocinnamylamino) ethyl]-5-isoquinolinesulfonamide dihydrochloride, as was the case with the activity of forskolin, suggesting downstream involvement of a cAMP-protein kinase A signaling pathway. The present results may suggest a physiological role of PACAP in vivo, and implicate the PACAP-cAMP signaling pathway for the possible therapeutic target of amyotrophic lateral sclerosis as glutamate excitotoxicity was suggested in sporadic amyotrophic lateral sclerosis.
 ...
PMID:Survival-promoting activity of pituitary adenylate cyclase-activating polypeptide in the presence of phosphodiesterase inhibitors on rat motoneurons in culture: cAMP-protein kinase A-mediated survival. 1871 11


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>