Sympathetic neurons of SCG (Superior Cervical Ganglia) send axonal projections either along the external carotid arteries to innervate the salivary glands, or along the internal carotid arteries to the lacrimal and pineal glands, the eye, blood vessels and skin of the head, and the mucosa of the oral and nasal cavities. Previous studies using Wnt1Cre and R26R have defined the neural crest and mesodermal origins of vascular smooth muscle in the heart outflow tract and great vessels, although not specifically of the segments that are relevant for the projections of the SCG neurons. The third pharyngeal arch arteries are lined by neural crest-derived smooth muscle, and consequently, their derivatives, including the entirety of the external carotid arteries and only the base of the internal carotid arteries, also have a neural crest origin. In contrast, the dorsal aortae are lined by smooth muscle that is mesodermal in origin, and as a result, the internal carotid arteries from just above their origination from the common carotid arteries have a mesoderm-derived smooth muscle layer. To address the possibility that guidance cues for SCG neurons are selectively expressed by the external carotid vs. the internal carotid arteries, we isolated these segments of the vasculature from mouse embryos at E13.5 and extracted RNA to screen microarrays for differentially expressed genes.
Endothelins are vascular-derived axonal guidance cues for developing sympathetic neurons.
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View SamplesTo explore the molecular basis of the distinct intrinsic membrane properties and other dstinguishing features of functionally defined DRG neuron subtypes, we bulk-sequenced RNA at high depth of genetically-labeled DRG neurons to generate transcriptome profiles of eight major DRG neuron subtypes. The trancriptome profiles revealed differentially expressed and functionally relevant genes, including voltage-gated ion channels. Guided by the transcriptome pofiles, electrophysiological analyses using pharmacological and genetic manipulations as well as computational modeling of DRG neuron subtypes were undertaken to assess the functions of select voltage-gated potassium channels (Kv1, Kv2, Kv3, and Kv4) in shaping action potential (AP) waveforms and firing patterns of the DRG neuron subtypes. Our findings show that the transcriptome profiles have predictive value for defining ion channel contributions to sensory neuron subtype-specific intrinsic physiological properties. Overall design: We made use of genetic tools developed that selectively label each of eight DRG neuron subtypes with fluorescent reporters, first purifying labeled neurons to homogeneity using flow cytometry (FACS) and then extracting RNA from these purified neuronal populations. DRGs from all axial levels were used for FACS, except for proprioceptors which were purified from thoracic ganglia, because the PVIRES-Cre; Ai14 proprioceptor labeling strategy was found to label a subset of limb level cutaneous LTMRs as well. DRGs from multiple mice were combined for FACS, and neurons from multiple rounds of sorting were combined to obtain sufficient amounts of RNA for each sequencing reaction. At least three biological replicates with a total of 26 samples were sequenced for each neuronal subtype. RNA libraries were prepared and subsequently sequenced using an Illumina HiSeq2000 platform at an average depth of ~70 million mapped reads per sample. This depth translates to an average detection level of 12,226 genes per sample. By using well characterized mouse lines for specific labeling of neuronal subtypes, this analysis links gene expression patterns to sensory neuron subtypes defined by their distinct in vivo properties as well as their corresponding intrinsic properties.
Deep Sequencing of Somatosensory Neurons Reveals Molecular Determinants of Intrinsic Physiological Properties.
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View SamplesWe report that developmental competition between sympathetic neurons for survival is critically dependent on a sensitization process initiated by target innervation and mediated by a series of feedback loops. Target-derived nerve growth factor (NGF) promoted expression of its receptor TrkA in neurons and prolonged TrkA-mediated signals. NGF also controlled expression of brain derived neurotrophic factor (BDNF) and neurotrophin-4 (NT4), which, through the receptor p75, can kill neighboring neurons with low retrograde NGFTrkA signaling whereas neurons with high NGFTrkA signaling are protected. Perturbation of any of these feedback loops disrupts the dynamics of competition. We suggest that three target-initiated events are essential for rapid and robust competition between neurons: sensitization, paracrine apoptotic signaling, and protection from such effects.
A model for neuronal competition during development.
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View SamplesTo understand better the factors contributing to keratoconus (KTCN), we used RNA sequencing to perform a transcriptome profile of human KTCN corneas. Over 82% of the genes and almost 75% of the transcripts detected as differentially expressed in KTCN and non-KTCN corneas were confirmed in the replication study using another set of samples. We used these differentially expressed genes to generate a network of KTCN-deregulated genes. We found an extensive disruption of collagen synthesis and maturation pathways, as well as downregulation of the core elements of the TGF-ß, Hippo, and Wnt signaling pathways influencing corneal organization. We identified long noncoding RNAs (lncRNAs) and conducted a computational analysis of their potential functions, and found that lncRNAs regulated the processing and expression of the aforementioned genes. This first comprehensive transcriptome profiling of human KTCN corneas points further to a complex etiology of KTCN. Overall design: Transcription profiling of 25 KTCN and 25 non-KTCN corneas using RNA-Seq
Collagen synthesis disruption and downregulation of core elements of TGF-β, Hippo, and Wnt pathways in keratoconus corneas.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Brain transcriptional and epigenetic associations with autism.
Age, Specimen part, Disease, Disease stage, Subject
View SamplesAutism is a common neurodevelopmental syndrome. Numerous rare genetic etiologies are reported; most cases are idiopathic. To uncover important gene dysregulation in autism we analyzed carefully selected idiopathic autistic and control cerebellar and BA19 (occipital) brain tissues using high resolution whole genome gene expression and DNA methylation microarrays. No changes in DNA methylation were identified in autistic brain but gene expression abnormalities in two areas of metabolism were apparent: down-regulation of genes of mitochondrial oxidative phosphorylation and of protein translation. We also found associations between specific behavioral domains of autism and specific brain gene expression modules related to myelin/myelination, inflammation/immune response and purinergic signaling. This work highlights two largely unrecognized molecular pathophysiological themes in autism and suggests differing molecular bases for autism behavioral endophenotypes.
Brain transcriptional and epigenetic associations with autism.
Age
View SamplesCalorie restriction (CR) enhances longevity and mitigates aging phenotypes in numerous species. Physiological responses to CR are cell-type specific and variable throughout the lifespan; however, the mosaic of molecular changes responsible CR benefits remain unclear, particularly in brain regions susceptible to deterioration throughout aging. Thus, we examined the influence of long-term CR on the CA1 hippocampal region, a key learning and memory brain area that is vulnerable to age-related pathologies, such as Alzheimer’s disease (AD). Through mRNA sequencing and NanoString nCounter analysis, we demonstrate that one year of CR feeding suppresses an age-dependent signature of 882 genes functionally associated with synaptic transmission-related pathways, including calcium signaling, long-term potentiation (LTP), and Creb signaling in wild-type mice. By comparing the influence of CR on hippocampal CA1 region transcriptional profiles at younger- (5 months) and older-adult (15 months) timepoints, we identify conserved upregulation of proteome quality control and calcium buffering genes, including heat shock 70 kDa proteins 1b and 5 (Hspa1b and Hspa5), protein disulfide isomerase family A members 4 and 6 (Pdia4 and Pdia6), and calreticulin (Calr). Expression levels of putative neuroprotective factors, klotho (Kl) and transthyretin (Ttr), are also elevated by CR throughout adulthood, although the global CR-specific expression profiles at young and older timepoints are highly divergent. At a previously unachieved resolution, our results demonstrate conserved activation of neuroprotective gene signatures and broad CR-suppression of age-dependent hippocampal CA1 region expression changes, indicating that CR functionally maintains a more youthful transcriptional state within hippocampal CA1 throughout aging. Overall design: Hippocampal CA1 region mRNA profiles of younger- (5 months) and older-adult (15 months) mice on calorie-restricted (CR) and normal (AD) diets were generated by deep sequencing using Illumina HiSeq 2500.
Calorie Restriction Suppresses Age-Dependent Hippocampal Transcriptional Signatures.
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View SamplesThe normal growth and function of mammary epithelial cells depend on interactions with the supportive stroma. Alterations in this communication can lead to the progression or expansion of malignant growth. The human mammary gland contains two distinctive types of fibroblasts within the stroma. The epithelial cells are surrounded by loosely connected intralobular fibroblasts, which are subsequently surrounded by the more compacted interlobular fibroblasts. The different proximity of these fibroblasts to the epithelial cells suggests distinctive functions for these two subtypes. In this report, we compared the gene expression profiles between the two stromal subtypes.
Interlobular and intralobular mammary stroma: genotype may not reflect phenotype.
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View SamplesConsider the problem of designing a panel of complex biomarkers to predict a patient's health or disease state when one can pair his or her current test sample, called a target sample, with the patient's previously acquired healthy sample, called a reference sample. As contrasted to a population averaged reference, this reference sample is individualized. Automated predictor algorithms that compare and contrast the paired samples to each other could result in a new generation of test panels that compare to a person's healthy reference to enhance predictive accuracy. This study develops such an individualized predictor and illustrates the added value of including the healthy reference for design of predictive gene expression panels. The objective is to predict each subject's state of infection, e.g., neither exposed nor infected, exposed but not infected, pre-acute phase of infection, acute phase of infection, post-acute phase of infection. Using gene microarray data collected in a large-scale serially sampled respiratory virus challenge study, we quantify the diagnostic advantage of pairing a person's baseline reference with his or her target sample.
An individualized predictor of health and disease using paired reference and target samples.
Specimen part, Subject, Time
View SamplesFull title: Prepubertal Human Spermatogonia and Mouse Gonocytes Share Conserved Gene Expression of Germline Stem Cell Regulatory Molecules
Prepubertal human spermatogonia and mouse gonocytes share conserved gene expression of germline stem cell regulatory molecules.
Age
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