Loss of function mutations in the SCN9a gene encoding voltage-gated sodium channel Nav1.7 cause congenital insensitivity to pain (CIP) and anosmia in otherwise normal humans and mice, suggesting that this channel may be a good analgesic drug target. Surprisingly, potent selective antagonists of Nav1.7 are weak analgesics. We therefore investigated whether Nav1.7 , as well as contributing to electrical signalling may have an additional function. Here we report that Nav1.7 deletion has profound effects on the sensory neuron transcriptome, leading to dysregulation of a number of transcription factors as well as upregulation of enkephalin precursor PENK mRNA and down regulation of CEACAM10 mRNA, a protein involved in noxious thermosensation. PENK mRNA is transcriptionally upregulated in Nav1.7 null mutant female sensory neurons, resulting in increased enkephalin expression in the dorsal horn of the spinal cord. PENK expression is down-regulated by addition of the sodium ionophore monensin, suggesting that sodium may play a role as a second messenger. Application of the opioid antagonist naloxone strongly enhances noxious peripheral input into the spinal cord, and dramatically reduces analgesia in both male and female Nav1.7 null mutant mice, as well as in human Nav1.7 null mutants. These data show that loss of Nav1.7 expression increases opioid drive over the lifetime of mice and humans. They further suggest that Nav1.7 channel blockers alone may not replicate the phenotype of null mutant humans and mice, but should be potentiated with exogenous opioids.
Endogenous opioids contribute to insensitivity to pain in humans and mice lacking sodium channel Nav1.7.
Specimen part
View SamplesThe area postrema (AP) is a sensory circumventricular organ characterised by extensive fenestrated vasculature and neurons which are capable of detecting circulating signals of osmotic, cardiovascular, immune and metabolic status. The AP can communicate these messages via efferent projections to brainstem and hypothalamic structures that are able to orchestrate an appropriate response. We have used microarrays to profile the transcriptome of the AP in the Sprague Dawley (SD) and Wistar Kyoto (WKY) rat and present here a comprehensive catalogue of gene expression, focussing specifically on the population of ion channels, receptors and G protein-coupled receptors (GPCRs) expressed in this sensory tissue; of the GPCRs expressed in the rat AP we identified ~36% that are orphans having no established ligand. We have also looked at the ways in which the AP transcriptome responds to the physiological stressors of 72-hours dehydration (DSD) and 48-hours fasting (FSD) and have performed microarrays under these conditions. Comparison between the DSD and SD or between FSD and SD revealed only a modest number of AP genes that are regulated by these homeostatic challenges. The expression levels of a much larger number of genes are altered in the spontaneously hypertensive rat (SHR) AP compared to the normotensive WKY controls however. Finally, analysis of these hypertension-related elements revealed genes that are involved in both the regulation of blood pressure and immune function and as such are excellent targets for further study.
The transcriptome of the medullary area postrema: the thirsty rat, the hungry rat and the hypertensive rat.
Sex, Specimen part
View SamplesMicroarrays were used to detail the global programme of gene expression comparing wild-type and RNAi knock-down plants of SPT4-1 and SPT4-2
The transcript elongation factor SPT4/SPT5 is involved in auxin-related gene expression in Arabidopsis.
Age, Specimen part
View SamplesHuman PB B cell subsets are functionally distinct and may derive from different developmental pathways, reflected by their differential gene expression profiles.
Functional capacities of human IgM memory B cells in early inflammatory responses and secondary germinal center reactions.
Specimen part
View SamplesGene expression profiles were compared between L-428 HRS cells transduced with shRNA against AP-1 transcription factor BATF3 and L-428 HRS cells transduced with a non-targeting shRNA as control.
An oncogenic axis of STAT-mediated BATF3 upregulation causing MYC activity in classical Hodgkin lymphoma and anaplastic large cell lymphoma.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A molecular portrait of gastrointestinal stromal tumors: an integrative analysis of gene expression profiling and high-resolution genomic copy number.
Sex, Age, Specimen part
View SamplesIn addition to KIT and PDGFRA mutations, sequential accumulation of other genetic events is involved in the development and progression of gastrointestinal stromal tumors (GISTs). Until recently, the significance of these other alterations has not been thoroughly investigated. The combination of gene expression profiling and high-resolution genomic copy number analysis offers a detailed molecular portrait of GISTs, providing an essential comprehensive knowledge necessary to guide the discovery of novel target genes involved in tumor development and progression.
A molecular portrait of gastrointestinal stromal tumors: an integrative analysis of gene expression profiling and high-resolution genomic copy number.
Sex, Age, Specimen part
View Samples