Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rett syndrome is an X-linked neurodevelopmental disorder caused by mutations in the gene encoding the transcriptional repressor methyl-CpG-binding protein 2 (MeCP2). Here we demonstrate that the Mecp2-null mouse model of Rett syndrome shows an age-dependent impairment in hippocampal CA1 long-term potentiation induced by tetanic or theta-burst stimulation. Long-term depression induced by repetitive low-frequency stimulation is also absent in behaviorally symptomatic Mecp2-null mice. Immunoblot analyses from behaviorally symptomatic Mecp2-null mice reveal altered expression of N-methyl-d-aspartate receptor subunits NR2A and NR2B. Presynaptic function is also affected, as demonstrated by a significant reduction in paired-pulse facilitation. Interestingly, the properties of basal neurotransmission are normal in the Mecp2-null mice, consistent with our observations that the levels of expression of synaptic and cytoskeletal proteins, including glutamate receptor subunits GluR1 and GluR2, PSD95, synaptophysin-1, synaptobrevin-2, synaptotagmin-1, MAP2, betaIII-tubulin and NF200, are not significantly altered. Together, these data provide the first evidence that the loss of Mecp2 expression is accompanied by age-dependent alterations in excitatory synaptic plasticity that are likely to contribute to the cognitive and functional deficits underlying Rett syndrome.
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PMID:Hippocampal synaptic plasticity is impaired in the Mecp2-null mouse model of Rett syndrome. 1608 43

Loss-of-function mutations or abnormal expression of the X-linked gene encoding methyl CpG binding protein 2 (MeCP2) cause a spectrum of postnatal neurodevelopmental disorders including Rett syndrome (RTT), nonsyndromic mental retardation, learning disability, and autism. Mice expressing a truncated allele of Mecp2 (Mecp2(308)) reproduce the motor and social behavior abnormalities of RTT; however, it is not known whether learning deficits are present in these animals. We investigated learning and memory, neuronal morphology, and synaptic function in Mecp2(308) mice. Hippocampus-dependent spatial memory, contextual fear memory, and social memory were significantly impaired in Mecp2(308) mutant males (Mecp2(308/Y)). The morphology of dendritic arborizations, the biochemical composition of synaptosomes and postsynaptic densities, and brain-derived neurotrophic factor expression were not altered in these mice. However, reduced postsynaptic density cross-sectional length was identified in asymmetric synapses of area CA1 of the hippocampus. In the hippocampus of symptomatic Mecp2(308/Y) mice, Schaffer-collateral synapses exhibited enhanced basal synaptic transmission and decreased paired-pulse facilitation, suggesting that neurotransmitter release was enhanced. Schaffer-collateral long-term potentiation (LTP) was impaired. LTP was also reduced in the motor and sensory regions of the neocortex. Finally, very early symptomatic Mecp2(308/Y) mice had increased basal synaptic transmission and deficits in the induction of long-term depression. These data demonstrate a requirement for MeCP2 in learning and memory and suggest that functional and ultrastructural synaptic dysfunction is an early event in the pathogenesis of RTT.
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PMID:Learning and memory and synaptic plasticity are impaired in a mouse model of Rett syndrome. 1639 2

Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (MECP2) that encodes a DNA binding protein involved in gene silencing. Selective deletion of Mecp2 in post-mitotic neurons in mice results in a Rett-like phenotype characterized by disturbances in motor activity and body weight, suggesting that these symptoms are exclusively caused by neuronal deficiency. Included in the RTT phenotype are episodes of respiratory depression that follow hyperventilation. Here we show that the respiratory phenotype depends on the organ distribution of Mecp2 deficiency. Both female mice heterozygous for a null mutation in Mecp2 (Mecp2+/-) and those with selective deletion of the protein in neurons (Mecp2+/nestin-Cre lox), showed an initial response to hypoxia that exceeded that in wild type (WT). However, marked respiratory depression following hypoxic hyperventilation was only seen in Mecp2+/- animals. Addition of carbon dioxide to the hypoxic exposure eliminated the respiratory depression. Tidal volume and lung volume were larger in Mecp2+/- and respiratory depression was directly related to tidal volume. Taken together these results indicate that the depression is due to hypocapnia. Respiratory depression in this mouse model of Rett Syndrome is seen in with ubiquitous deficiency in Mecp2 but not when it is confined to neurons.
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PMID:Separate respiratory phenotypes in methyl-CpG-binding protein 2 (Mecp2) deficient mice. 1654 21

The family of hydroxymethylglutaryl coenzyme A reductase inhibitors, collectively known as statins, are used clinically to reduce plasma cholesterol levels. Recent reports indicate that statin therapy is associated with a reduced risk of depression, although the mechanism underlying this antidepressant effect is unknown. Evidence suggests that increasing central BDNF activity plays an important role in the treatment of major depression. In the nervous system, the proteolytic cleavage of pro-BDNF, a BDNF precursor, to BDNF through the tissue-type plasminogen activator (tPA)-plasmin pathway represents one mechanism that can regulate the action of BDNF. In vitro studies have demonstrated that statins can induce tPA and inhibit plasminogen activator inhibitor-1, the major inhibitor of tPA. It is therefore possible that statins could act through the tPA-plasminogen pathway to increase BDNF and achieve an antidepressant effect. It is suggested that statins could be of therapeutic potential for patients with major depression: especially those that have an abnormality in the tPA-plasminogen pathway or comorbidities relating to cardiovascular disease. Furthermore, BDNF dysfunction has also been implicated in several other neuropsychiatric diseases, such as Alzheimer's disease, attention-deficit hyperactivity disorder and Rett syndrome. The potential use of statins in these diseases may warrant further exploration.
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PMID:Statins may enhance the proteolytic cleavage of proBDNF: implications for the treatment of depression. 1735 Jul 66

Rett syndrome is a neurodevelopmental disorder caused by mutations in the X-chromosomal MECP2 gene encoding for the transcriptional regulator methyl CpG binding protein 2 (MeCP2). Rett patients suffer from episodic respiratory irregularities and reduced arterial oxygen levels. To elucidate whether such intermittent hypoxic episodes induce adaptation/preconditioning of the hypoxia-vulnerable hippocampal network, we analyzed its responses to severe hypoxia in adult Rett mice. The occurrence of hypoxia-induced spreading depression (HSD)--an experimental model for ischemic stroke--was hastened in Mecp2-/y males. The extracellular K+ rise during HSD was attenuated in Mecp2-/y males and the input resistance of CA1 pyramidal neurons decreased less before HSD onset. CA1 pyramidal neurons were smaller and more densely packed, but the cell swelling during HSD was unaffected. The intrinsic optical signal and the propagation of HSD were similar among the different genotypes. Basal synaptic function was intact, but Mecp2-/y males showed reduced paired-pulse facilitation and higher field potential/fiber volley ratios, but no increased seizure susceptibility. Synaptic failure during hypoxia was complete in all genotypes and the final degree of posthypoxic synaptic recovery indistinguishable. Cellular ATP content was normal in Mecp2-/y males, but their hematocrit was increased as was HIF-1alpha expression throughout the brain. This is the first study showing that in Rett syndrome, the susceptibility of telencephalic neuronal networks to hypoxia is increased; the underlying molecular mechanisms apparently involve disturbed K+ channel function. Such an increase in hypoxia susceptibility may potentially contribute to the vulnerability of male Rett patients who are either not viable or severely disabled.
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PMID:Enhanced hypoxia susceptibility in hippocampal slices from a mouse model of rett syndrome. 1907 93

The approval of suberoylanilide hydroxamic acid by the FDA for the treatment of cutaneous T-cell lymphoma in October, 2006 sparked a dramatic increase in the development of inhibitors for the class of enzymes known as the histone deacetylases (HDACs). In recent years, a large number of combination therapies involving histone deacetylase inhibitors (HDACIs) have been developed for the treatment of a variety of malignancies and neurodegenerative disorders. Promising evidence has been reported for the treatment of pancreatic cancer, prostate cancer, and leukemia as well as a number of other previously difficult to treat cancers. Drug combination approaches have also shown promise for the treatment of mood disorders including bipolar disorder and depression. In addition to these drug combination approaches, HDACIs alone have demonstrated effectiveness in the treatment of Parkinson's disease, Alzheimer's disease, Rubinstein-Taybi syndrome, Rett syndrome, Friedreich's ataxia, Huntington's disease, multiple sclerosis, anxiety, and schizophrenia. Adverse inflammatory affects observed with traumatic brain injury and arthritis have also been alleviated by treatment with certain HDACIs. Based on the diverse utility and wide range of mechanistic actions observed with this class of drugs, the future development of better drug combination therapies and more selective HDACIs is warranted.
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PMID:Creating zinc monkey wrenches in the treatment of epigenetic disorders. 1954 31

Neurotrophins, particularly, NGF and BDNF are now well recognized to mediate a dizzying number of trophobiological effects, ranging from the Rita Levi-Montalcini's neurotrophic through immunotrophic to metabotrophic effects.These are implicated in the pathogenesis of various diseases including neuropsychiatric and cardiometabolic diseases, such as dementia, depression, type 2 diabetes and obesity that may express a common phenotype and coexistence. Recently, adipobiology (adiposcience) as become a focus of numerous studies showing that the adipose tissue is the body's largest endocrine organ producing multiple signaling proteins, including NGF and BDNF, all these dubbed adipokines. On the basis of our and other authors' evidence that low NGF and/or BDNF levels are found in cardiometabolic diseases (atherosclerosis, obesity, type 2 diabetes, metabolic syndrome), a hypothesis of a critical role of neuro-metabotrophic deficit in the pathogenesis of these diseases has been raised. Since NGF and BDNF also exerts various synaptotrophic effects involved in cognitive enhancement, this hypothesis might also be related to neuropsychiatric diseases such as dementia, depression, schizophrenia, autism, Rett syndrome, anorexia nervosa, and bulimia nervosa. Finally, NGF- and BDNF-based therapeutic approach, including ampakines, antidepressants, selective deacetylase inhibitors, statins, peroxisome proliferator-activated receptor gamma agonists, and "brain food" and calorie restriction, is outlined.
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PMID:NGF and BDNF: from nerves to adipose tissue, from neurokines to metabokines. 2006 8

Early-life stress induces persistent memory traces on our genes and programs the life-long risk for depression. Epigenetic marking of the arginine vasopressin (AVP) gene by early-life stress in mice underpins sustained expression and increased hypothalamic-pituitary-adrenal axis activity, triggering endocrine and behavioral alterations that are frequent features in depression. This epigenetic memory evolves in two steps coordinated by the epigenetic reader and writer MeCP2. While early derepression of AVP is driven by neuronal activity causing Ca2+/calmodulin kinase-dependent phosphorylation and dissociation of MeCP2, subsequent hypomethylation at the AVP enhancer gradually develops to sustain derepression. In a vicious circle MeCP2 occupancy uncouples from the initial stimulus and leads to the hard-coding of early-life experience at the level of DNA methylation. The sequential order of these events demarcates the transition from a preliminary to a persistent, possibly irreversible, epigenetic memory and thus defines a critical time window for the timely therapy of severe trauma.
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PMID:Genes learn from stress: how infantile trauma programs us for depression. 2033 19

Rett syndrome is a severe neurodevelopmental disorder mainly caused by mutations in the transcriptional regulator MeCP2. Although there is no effective therapy for Rett syndrome, the recently discovered disease reversibility in mice suggests that there are therapeutic possibilities. Identification of MeCP2 targets or modifiers of the phenotype can facilitate the design of curative strategies. To identify possible novel MeCP2 interactors, we exploited a bioinformatic approach and selected Ying Yang 1 (YY1) as an interesting candidate. We demonstrate that MeCP2 interacts in vitro and in vivo with YY1, a ubiquitous zinc-finger epigenetic factor regulating the expression of several genes. We show that MeCP2 cooperates with YY1 in repressing the ANT1 gene encoding a mitochondrial adenine nucleotide translocase. Importantly, ANT1 mRNA levels are increased in human and mouse cell lines devoid of MeCP2, in Rett patient fibroblasts and in the brain of Mecp2-null mice. We further demonstrate that ANT1 protein levels are upregulated in Mecp2-null mice. Finally, the identified MeCP2-YY1 interaction, together with the well-known involvement of YY1 in the regulation of D4Z4-associated genes at 4q35, led us to discover the anomalous depression of FRG2, a subtelomeric gene of unknown function, in Rett fibroblasts. Collectively, our data indicate that mutations in MeCP2 might cause the aberrant overexpression of genes located at a specific locus, thus providing new candidates for the pathogenesis of Rett syndrome. As both ANT1 mutations and overexpression have been associated with human diseases, we consider it highly relevant to address the consequences of ANT1 deregulation in Rett syndrome.
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PMID:The MeCP2/YY1 interaction regulates ANT1 expression at 4q35: novel hints for Rett syndrome pathogenesis. 2050 95

Recent research has demonstrated that complex 'epigenetic' mechanisms, which regulate gene transcription without altering the DNA code, could play a critical role in the pathophysiology of psychiatric disorders. The present review summarizes recent evidence for the existence of sustained epigenetic mechanisms of gene regulation in several psychiatric disorders such as depression, schizophrenia and Rett syndrome. The gene transcriptions of the key molecules such as brain-derived neurotrophic factor (BDNF) or Reelin that play a role in on psychiatric disorders are regulated with histone modification or DNA methylation. Furthermore, one potential mechanism whereby stress can disrupt prenatal and/or neonatal development is through epigenetics, because the key issue of epigenetics is its long-term influence. In addition, we also found in the recent research that the epigenetic mechanism of gene regulation, especially histonedeacetylase, in the brain may be involved in the development of emotional resistance to stress stimuli. A better understanding of epigenetic regulation might provide new therapeutic avenues for disorders such as depression, schizophrenia, Rett syndrome and neurodevelopmental diseases.
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PMID:[Update on epigenetic regulation in pathophysiologies of stress-induced psychiatric disorders]. 2085 92


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