Project description:Water permeability of the kidney collecting ducts is regulated in part by the amount of the molecular water channel protein aquaporin-2 (AQP2), whose expression, in turn, is regulated by the pituitary peptide hormone vasopressin. We previously showed that stable glucocorticoid receptor knockdown diminished the vasopressin-induced Aqp2 gene expression in the collecting duct cell model mpkCCD. Here, we investigated the pathways regulated by the glucocorticoid receptor by comparing transcriptomes of the mpkCCD cells with or without stable glucocorticoid receptor knockdown. Glucocorticoid receptor knockdown downregulated 5,394 transcripts associated with 55 KEGG pathways including “vasopressin-regulated water reabsorption,” indicative of positive regulatory roles of these pathways in the vasopressin-induced Aqp2 gene expression. Quantitative RT-PCR confirmed the downregulation of the vasopressin V2 receptor transcript upon glucocorticoid receptor knockdown. Glucocorticoid receptor knockdown upregulated 3,785 transcripts associated with 42 KEGG pathways including the “TNF signaling pathway” and “TGFβ signaling pathway,” suggesting the negative regulatory roles of these pathways in the vasopressin-induced Aqp2 gene expression. Quantitative RT-PCR confirmed the upregulation of TNF and TGFβ receptor transcripts upon glucocorticoid receptor knockdown. TNF or TGFβ inhibitor alone, in the absence of vasopressin, did not induce Aqp2 gene transcription. However, TNF or TGFβ blunted the vasopressin-induced Aqp2 gene expression. In particular, TGFβ reduced vasopressin-induced increases in Akt phosphorylation without inducing epithelial-to-mesenchymal transition or interfering with vasopressin-induced apical AQP2 trafficking. In summary, our RNA-seq transcriptomic comparison revealed positive and negative regulatory pathways maintained by the glucocorticoid receptor for the vasopressin-induced Aqp2 gene expression.
2022-05-16 | GSE194044 | GEO
Project description:LDLR Multiplexed Assays of Variant Effects
Project description:In mammals, the peptide hormone vasopressin controls renal water excretion, largely through regulation of the molecular water channel aquaporin-2 (AQP2) in the renal collecting duct. Regulatory mechanisms of AQP2 show: 1) short-term regulation by membrane trafficking; and 2) long-term regulation involving vasopressin-induced changes in the abundance of the aquaporin-2 protein. Vasopressin activates a G protein-coupled receptor (V2R) increasing cyclic AMP and activating protein kinase PKA. Crebbp and Ep300 are known targets of PKA. They are histone acetyltransferases that acetylate histone H3 lysine-27, a histone mark associated with open chromatin and increased transcription (Tie F et al. Development 2009). The translocation of CREBBP and Ep300 into the nucleus in response to vasopressin in the collecting duct cells, predicts that vasopressin, working through PKA, may increase histone H3K27 acetylation of some genes. We tested this by performing ChIP-Seq for this modification.
Project description:Vasopressin regulates renal water excretion by binding to the Gs-coupled vasopressin receptor (V2R) in collecting duct cells, resulting in cyclic AMP-dependent increases in epithelial water permeability through regulation of the aquaporin-2 (AQP2) water channel. Our prior studies showed that CRISPR-mediated deletion of protein kinase A (PKA) in cultured mpkCCD cells largely eliminates these regulatory events. These PKA-null cells provide a means of identifying PKA-independent signaling downstream from the V2 receptor. We carried out large-scale quantitative protein mass spectrometry (SILAC) to identify PKA-independent phosphorylation changes in response to V2R-selective vasopressin analog, dDAVP. The results show that V2R-mediated vasopressin signaling is predominantly, but not entirely, PKA-dependent. Target motif analysis of the phosphopeptides increased in response to dDAVP in PKA-null cells indicates that the vasopressin activates of one or more members of the AMPK/SNF1 subfamily of basophilic protein kinases. Among the upregulated phosphorylation sites were three known targets of SNF1-subfamily kinases, namely Lipe (S559), Crtc1 (S151) and Arhgef2 (S151). One of the phosphorylation sites that increased in occupancy in PKA-null cells was Ser256 of AQP2, a site critical for vasopressin-mediated trafficking of AQP2 to the cell surface. Beyond this, PKA-independent active site phosphorylation changes were also seen for protein kinases Stk39 (SPAK) and Prkci (Protein kinase C iota). Cyclic AMP levels were ~10-fold higher in PKA-null than in PKA-intact cells in the presence of phosphodiesterase inhibitor IBMX, consistent with a marked acceleration of cAMP production in PKA-null cells. The findings are indicative of substantial PKA-independent signaling downstream from the Gs-coupled V2 receptor.
Project description:Vasopressin is the major hormone that regulates renal water excretion. It does so by binding to a receptor in renal collecting duct cells, triggering signaling pathways that ultimately regulate the abundance, location, and activity of the water channel protein aquaporin 2. We took an advantage of quantitative large scale proteomic technologies and oligonucleotide microarrays to quantify steady state changes in protein and transcript abundances in response to vasopressin in a collecting duct cell line, mpkCCD clone 11 (Yu et al. PNAS 2009, 106:2441-2446). This cell line originally developed by Alan Vandewalle’s group recapitulates vasopressin-mediated AQP2 expression and phosphorylation as seen in native colleting duct cells. The mpkCCD cells were grown on membrane supports to permit polarization. Once transepithelial resistance reached 5kohm per centimeter square and higher, the cells were exposed to the vasopressin V2 receptor analog, dDAVP, at a physiological concentration, 0.1nM, for 5 days. Control experiments were done with cells exposed to vehicle alone. Total RNA was harvested and processed for transcript expression analysis using Affymetrix GeneChip Mouse Genome 430 2.0 Arrays. Each experimental treatment, vehicle and dDAVP, was repeated 3 times.
Project description:Multiplexed assays of variant effect are powerful methods to profile the consequences of rare variants on gene expression and organismal fitness. Yet, few studies have integrated several multiplexed assays to map variant effects on gene expression in coding sequences. Here, we pioneered a multiplexed assay based on polysome profiling to measure variant effects on translation at scale, uncovering single-nucleotide variants that increase and decrease ribosome load. By combining high-throughput ribosome load data with multiplexed mRNA and protein abundance readouts, we mapped the cis-regulatory landscape of thousands of catechol-O-methyltransferase (COMT) variants from RNA to protein and found numerous coding variants that alter COMT expression. Finally, we trained machine learning models to map signatures of variant effects on COMT gene expression and uncovered both directional and divergent impacts across expression layers. Our analyses reveal expression phenotypes for thousands of variants in COMT and highlight variant effects on both single and multiple layers of expression. Our findings prompt future studies that integrate several multiplexed assays for the readout of gene expression
Project description:Vasopressin, a peptide hormone, controls renal water excretion, largely through regulation of water channel aquaporin-2 (AQP2) in the renal collecting duct. There are two regulatory mechanisms of AQP2: 1) short-term regulation by membrane trafficking of AQP2; and 2) long-term regulation involving vasopressin-induced changes of protein abundance of AQP2 through regulation of gene transcription and protein half-life. Vasopressin binds a G protein-coupled receptor (V2R) activating a cyclic AMP/protein kinase A (PKA) signaling pathway. Sequentially, after activation of cAMP/PKA signaling, many of transcription factors involve gene transcription process. cAMP-response element binding protein (CREB) and cAMP-responsive transcription factor C/EBP beta are potential candidates for vaopressin-mediated regulation of Aqp2 gene transcription proviously reported. In the present study, genome-wide binding sites for two b-ZIP transcription factors CREB and C/EBP beta were identified in vasopressin-responsive mouse collecting duct mpkCCD cells using ChIP-Seq.
Project description:Vasopressin is the major hormone that regulates renal water excretion. It does so by binding to a receptor in renal collecting duct cells, triggering signaling pathways that ultimately regulate the abundance, location, and activity of the water channel protein aquaporin 2. We took an advantage of quantitative large scale proteomic technologies and oligonucleotide microarrays to quantify steady state changes in protein and transcript abundances in response to vasopressin in a collecting duct cell line, mpkCCD clone 11 (Yu et al. PNAS 2009, 106:2441-2446). This cell line originally developed by Alan Vandewalle’s group recapitulates vasopressin-mediated AQP2 expression and phosphorylation as seen in native colleting duct cells.
Project description:Vasopressin, a peptide hormone, controls renal water excretion, largely through regulation of water channel aquaporin-2 (AQP2) in the renal collecting duct. There are two regulatory mechanisms of AQP2: 1) short-term regulation by membrane trafficking of AQP2; and 2) long-term regulation involving vasopressin-induced changes of protein abundance of AQP2 through regulation of gene transcription and protein half-life. Vasopressin binds a G protein-coupled receptor (V2R) activating several downstream signaling pathways. At downstream of V2R activation, many of transcription factors involve gene transcription process associated with status of chromatin structure. ATAC-Seq (Assay for Transpoase-Accessible Chromatin using Sequencing) is a recent technique to study chromatin accessibility (Buenrostro et al. Nat Methods 2013). We carried out ATAC-Seq following standard an ATAC-Seq protocol in mpkCCD cells treated with vehicle or dDAVP for 30 minutes.
Project description:In this study, we analyzed the transcriptome of a highly differentiated mouse clonal CCD principal cell line (mpkCCD(cl4)) and the changes in the transcriptome induced by aldosterone and vasopressin. Serial analysis of gene expression (SAGE) was performed on untreated cells and on cells treated with either aldosterone or vasopressin for 4 h. The transcriptomes in these three experimental conditions were determined by sequencing 169,721 transcript tags from the corresponding SAGE libraries. Limiting the analysis to tags that occurred twice or more in the data set, 14,654 different transcripts were identified, 3,642 of which do not match known mouse sequences. Statistical comparison (at P < 0.05 level) of the three SAGE libraries revealed 34 AITs (aldosterone-induced transcripts), 29 ARTs (aldosterone-repressed transcripts), 48 VITs (vasopressin-induced transcripts) and 11 VRTs (vasopressin-repressed transcripts). A selection of the differentially-expressed, hormone-specific transcripts (5 VITs, 2 AITs and 1 ART) has been validated in the mpkCCD(cl4) cell line either by Northern blot hybridization or reverse transcription-PCR. The hepatocyte nuclear transcription factor HNF-3-alpha (VIT39), the receptor activity modifying protein RAMP3 (VIT48), and the glucocorticoid-induced leucine zipper protein (GILZ) (AIT28) are candidate proteins playing a role in physiological responses of this cell line to vasopressin and aldosterone. Keywords: other