Project description:The goals of this study are to compare the transcriptomes of control heterozygous and Tuberous sclerosis 2 (Tsc2) homozygous nociceptors that have been enriched by fluorescence-associated cell sorting (FACS) with the aim of identifying differences in genes associated with sensory behavior. Nav1.8-Cre transgenic mice were used to delete Tsc2 as well as express Green fluorescent protein from the Rosa26 locus. Tsc2 deletion constitutively activates mTORC1 signaling cell autonomously. Dissociated dorsal root ganglia from adult mice were FACS-sorted for GFP and analyzed by RNA-seq. We find that a number of sensory behavior associated genes are affected by Tsc2 deletion including Calca, Ntrk1, Mrgpra3, and Nppb. Additionally, profiling of ion channel expression showed a reduction in almost half of expressed sodium, potassium and calcium channel as well as G-protein coupled receptors. Other categories of genes such as transcription factors and ligand-gated ion channels contained an even numbers of up- and downregulated genes with many that did not change as a result of Tsc2 deletion. In addition, expression of most marker genes enriched in Isolectin B4 (IB4) negative neurons were strongly reduced in Tsc2 mutant nociceptors, consistent with reduced sensitivity to heat, which is a modality related to these neurons. We conclude Tsc2 deletion and consequent mTORC1 activation alters gene expression of nociceptors resulting in altered sensory thresholds.
Project description:The goals of this study are to compare the transcriptomes of control heterozygous and Tuberous sclerosis 2 (Tsc2) homozygous nociceptors 3 days after sciatic nerve injury that have been enriched by fluorescence-associated cell sorting (FACS) with the aim of identifying differences in genes associated with axon regeneration. Nav1.8-Cre transgenic mice were used to delete Tsc2 as well as express Green fluorescent protein from the Rosa26 locus. Tsc2 deletion constitutively activates mTORC1 signaling cell autonomously. Dissociated dorsal root ganglia from adult mice were FACS-sorted for GFP and analyzed by RNA-seq. We find that the expression of a number of regeneration-associated transcription factors including cJun, Atf3, Sox11 and other are upregulated in Tsc2 mutant neurons in the absence of an injury. Additionally, the target genes of several other normally expressed regeneration-associated transcription factors are differentially expressed in Tsc2 mutant neurons, such as Creb1 and Klf’s. We conclude Tsc2 deletion and consequent mTORC1 activation establishes a pro-regenerative gene expression profile in nociceptors in the absence of an injury.
Project description:Transcriptome analysis of the heads of 5 dpf epdc5-/-, tsc2-/-, depdc5-/- x tsc2-/- and wildtype zebrafish larvae to provide insights into the neuropathological processes underlying the observed epileptic phenotype in sv2a-/- zebrafish larvae.
Project description:We explored the effects of nociceptors on DC under various conditions by means of in vitro coculture of Flt3L-induced bone marrow-derived DCs and primary mouse nociceptors.
Project description:The metabolic status of individual cells in microbial cultures can differ being relevant for biotechnology, environmental and medical microbiology. However, it is hardly understood in molecular detail due to limitations of current analytical tools. Here, we demonstrate that FACS in combination with proteomics can be used to sort and analyze cell populations based on their metabolic state. A previously established GFP reporter system was used to detect and sort single Corynebacterium glutamicum cells based on the concentration of branched chain amino acids (BCAA) using FACS. A proteomics workflow optimized for small cell numbers was used to quantitatively compare proteomes of a ?aceE mutant, lacking functional pyruvate dehydrogenase (PD), and the wild type. About 800 proteins could be quantified from 1,000,000 cells. In the ?aceE mutant BCAA production was coordinated with upregulation of the glyoxylate cycle and TCA cycle to counter the lack of acetyl CoA resulting from the deletion of aceE.
Project description:The tuberous sclerosis complex (TSC) family of tumor suppressors, TSC1 and TSC2, function together in an evolutionarily conserved protein complex that is a point of convergence for major cell signaling pathways that regulate mTOR complex 1 (mTORC1). Mutation or aberrant inhibition of the TSC complex is common in various human tumor syndromes and cancers. The discovery of novel therapeutic strategies to selectively target cells with functional loss of this complex is therefore of substantial clinical relevance to TSC and sporadic cancers. We developed a CRISPR-based method to generate homogenous mutant Drosophila cell lines. By combining TSC1 and TSC2 mutant cell lines with RNAi screens against all kinases and phosphatases, we identified synthetic interactions with TSC1 and TSC2. Knockdown of three candidate genes (mRNA-cap, Pitslre and CycT; orthologs of RNGTT, CDK11 and CCNT1 in humans) reduced the population growth rate of both Drosophila TSC1 and TSC2 mutant cells but not that of wild-type cells. Moreover, knockdown of all three genes displayed similar selective effects in mammalian TSC2-deficient cell lines, including human tumor-derived cells, illustrating the power of this cross species screening strategy to identify potential drug targets.
Project description:Silent nociceptors are sensory afferents that are insensitive to noxious mechanical stimuli under normal conditions but become sensitized to such stimuli during inflammation. We had previously shown that mouse silent nociceptors express the nicotinic acetylcholine receptor alpha-3 subunit (CHRNA3) and can thus readily be identified in Tg(Chrna3-EGFP)BZ135Gsat reporter mice (Prato et al. Cell Reports 2017). Most importantly, we had shown that CHRNA3+ slient nociceptors acquire mechanosensitivity upon treatment with the inflammatory mediator nerve growth factor and demonstrated that this process requires de-novo gene transcription. Here, we performed paired-end RNA-sequencing to identify transcripts that might be involved in the acquisition of mechanosenstivity in mouse silent nociceptors.
Project description:The goal of this study was to analyze global gene expression in specific populations of nociceptor sensory neurons, the neurons that detect damaging/noxious stimuli. The dorsal root ganglia (DRG), trigeminal ganglia, and nodose ganglia are anatomically distinct peripheral sensory ganglia that contain nociceptors which innervate skin, gut, lungs, and other distinct organ tissues. We used flow cytometry to purify nociceptors from these ganglia and profiled their global gene expression signatures to compare gene expression between these different anatomically distinct nociceptors. Nav1.8-Cre were bred with Rosa26-TdTomato to generate Nav1.8-Cre/R26-TdTomato reporter progeny, where all peripheral nociceptor neurons are genetically marked with red fluroescence due to specific expression of the TTX- resistant sodium channel Nav1.8. Lumbar region dorsal root ganglia (DRG), trigeminal ganglia, and nodose ganglia were dissected from mice (3 mice were pooled/sample). Highly red fluorescent neurons were Facs purified, RNA extracted, and processed for microarray analysis.