Project description:Conscious awareness of breathing requires the activation of higher brain centers. The sensation of breathing is believed to be a neural gating process. The thalamus provides the brain structure that could be responsible for the gating of respiratory sensory information to the cortex. It was reasoned that if the thalamus is the neural gate, then tracheal obstructions will modulate the gene expression profile of the thalamus. Anesthetized rats were instrumented with an inflatable cuff sutured around the trachea. The cuff was inflated to obstruct 2-4 breaths, then deflated for a minimum of 15 breaths. The obstructions were repeated for 10 min followed by immediate brain removal, and the medial thalamus was dissected and prepared for microarray analysis. Gene expression profiles were measured using Agilent Technology Oligo Microarrays. Following the occlusion protocol, 588 genes were found to be altered (p < 0.05, log2 fold change ≥ 0.4), with 327 down-regulated and 261 genes up-regulated. A significant up-regulation of the serotonin HTR2A receptor and significant down-regulation of the dopamine DRD1 receptor genes were found. A pathway analysis was performed targeting serotonin and dopamine receptor pathways. The mitogen activated protein kinase 1 (MAPK1) gene was significantly down-regulated. MAPK1 is an inhibitory regulator of the serotonin HTR2A receptor and facilitatory regulator for the dopamine DRD1 receptor. Down-regulation of MAPK1 may be related to the 2-fold up-regulation of HTR2A and 2-fold down-regulation of DRD1 suggesting an interaction in the medial thalamus serotonin-dopamine pathway elicited by airway obstruction. These results demonstrate an immediate change in gene expression in thalamic arousal-fear-anxiety-motivation related serotonin and dopamine receptors in response to airway obstruction. The results support the hypothesis that the thalamus is a component in the respiratory mechanosensory neural pathway. Four experimental animals that received tracheal occlusions and four surgical control animals were used. A reference design was used to compare all samples.

Project description:The thalamus may be the critical brain area involved in sensory gating and the relay of respiratory mechanical information to the cerebral cortex for the conscious awareness of breathing. We hypothesized that respiratory mechanical stimuli in the form of tracheal occlusions would modulate the gene expression profile of the thalamus. Specifically, it was reasoned that conditioning to the respiratory loading would induce a state change in the medial thalamus consistent with a change in sensory gating and the activation of molecular pathways associated with learning and memory. In addition, respiratory loading is stressful and thus should elicit changes in gene expressions related to stress, anxiety, and depression. Rats were instrumented with inflatable tracheal cuffs. Following surgical recovery, they underwent ten days (5 days/week) of transient tracheal occlusion conditioning. On day 10, the animals were sacrificed and the brains removed. The medial thalamus was dissected and microarray analysis of gene expression performed. Tracheal obstruction conditioning modulated a total of 661 genes (p < 0.05, log2 fold change ≥ 0.58), 250 genes were down-regulated and 411 up-regulated. There was a significant down-regulation of GAD1, GAD2 and HTR1A, HTR2A genes. CCK, PRKCG, mGluR4, and KCJN9 genes were significantly up-regulated. Some of these genes have been associated with anxiety and depression, while others have been shown to play a role in switching between tonic and burst firing modes in the thalamus and thus may be involved in gating of the respiratory stimuli. Furthermore, gene ontology and pathway analysis showed a significant modulation of learning and memory pathways. These results support the hypothesis that the medial thalamus is involved in the respiratory sensory neural pathway due to the state change of its gene expression profile following repeated tracheal occlusions. Four experimental animals that received tracheal occlusions and four surgical control animals were used. A reference design was used to compare all samples.

Project description:Appetite is frequently affected in cancer patients, leading to anorexia and consequently insufficient food intake. In this study, we report on hypothalamic gene expression profile of a cancer cachectic mouse model with increased food intake. In this model, mice bearing C26 colon adenocarcinoma have an increased food intake subsequently to the loss of body weight. We hypothesize that in this model, appetite regulating systems in the hypothalamus, which apparently fail in anorexia, are still able to adapt adequately to changes in energy balance. Therefore studying the changes that occur on appetite regulators in the hypothalamus might reveal targets for treatment of cancer-induced eating disorders. By applying transcriptomics, many appetite regulating systems in the hypothalamus could be taken into account, providing an overview of changes that occur in the hypothalamus during tumour growth. We show that hypothalamic expression of orexigenic neuropeptides NPY and AgRP was higher, whereas expression of anorexigenic genes CCK and POMC were lower in TB compared to controls. In addition, serotonin and dopamine signalling pathways were found to be significantly altered in TB mice. Serotonin levels in brain showed to be lower in TB mice compared to control mice, while dopamine levels did not change. Moreover, serotonin levels inversely correlated with food intake. Transcriptomic analysis of the hypothalamus of cachectic TB mice with an increased food intake showed changes in NPY, AgRP and serotonin signalling. Serotonin levels in the brain showed to correlate with changes in food intake. Targeting these systems seems a promising strategy to avoid the development of cancer-induced eating disorders. C26-colon adenocarcinoma cells were subcutaneously inoculated in CDF1 mice. After 20 days, hypothalami were dissected and subjected to gene expression profiling. The total dataset consists of 2 parts; dataset 1, a pilot stuy in which mice were injected with increasing number of tumour cells and pooled samples were arrayed; and dataset 2, the main study in which mice were injected with 1 million tumour cells and samples were individually arrayed.

Project description:L-3,4-dihydroxyphenylalanine (levodopa) treatment is the major pharmacotherapy for Parkinson's disease. However, almost all patients receiving levodopa eventually develop debilitating involuntary movements (dyskinesia). While it is known that striatal spiny projection neurons (SPNs) are involved in the genesis of this movement disorder, the molecular basis of dyskinesia is not understood. In this study, we identify distinct cell-type-specific gene expression changes that occur in sub-classes of SPNs upon induction of a parkinsonian lesion followed by chronic levodopa treatment. We identify several hundred genes whose expression is correlated with levodopa dose, many of which are under the control of AP-1 and ERK signaling. In spite of homeostatic adaptations involving several signaling modulators, AP-1-dependent gene expression remains highly dysregulated in direct pathway SPNs (dSPNs) upon chronic levodopa treatment. We also discuss which molecular pathways are most likely to dampen abnormal dopaminoceptive signaling in spiny projection neurons, hence providing potential targets for antidyskinetic treatments in Parkinson's disease. To profile the cell-type-specific responses of striatal spiny projection neurons (SPNs) to striatal dopamine depletion, we conducted TRAP analysis of the two major classes of these neurons: dSPNs that express the dopamine receptor 1a (Drd1a), and iSPNs that express the dopamine receptor 2 (Drd2). To disrupt dopamine innervation to both of these SPN populations that reside in the striatum, we injected the neurotoxin 6-hydroxydopamine (6-OHDA), unilaterally, in the medial forebrain bundle (MFB) in hemizygous Drd1-TRAP and Drd2-TRAP adult (9-14 weeks) male mice (kept on a C57BL/6J genetic background). This lesion procedure causes nigral dopamine cell death within a few days, along with a widespread and near-complete loss of dopaminergic innervation to the entire dorsal striatum on one side of the brain (a hemiparkinsonian model). We first examined the effects of dopamine depletion alone, compared to a mock lesion (ascorbate / saline injected). We then examined the effects of chronic levodopa treatment upon the molecular profiles of dopamine- depleted dSPNs and iSPNs, with two dose regimens. The ‘high-dose’ L-DOPA regimen (3 mg/kg on days 1-3, followed by 6 mg/kg on days 4-9) was expected to induce severe dyskinesia in all MFB-lesioned mice. The low-dose L-DOPA regimen (1 mg/kg on days 1-3, followed by 2 mg/kg on days 4-9) was expected to reverse limb use asymmetry without causing conspicuous dyskinesias. To equalize the effects of stress and handling across all groups, including control groups, all mice were equally handled and thus received saline injections when not receiving levodopa injections. Each treatment group contained 7-10 replicates. TRAP-purified mRNAs from either Drd1a- or Drd2-expressing SPNs were reverse-transcribed, amplified, and used to interrogate Affymetrix 430_2.0 GeneChip microarrays.

Dataset Information

Tracheal Occlusion Modulates the Gene Expression Profile of the Medial Thalamus in Anesthetized Rats

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure