Project description:Vasopressin, the antidiuretic hormone, acts on the renal collecting duct. In this experiment both vasopressin (AVP) and the V2R specific agonist dDAVP were infused into Aquaporin 1 knockout animals for 7 days. The aim of the experiment was to identify genes increased by vasopressin receptors in the renal medullary collecting ducts, in the absence of an increase in renal medullary osmolarity (the AQP1 knockouts are concentrating mechanism knockouts). All experiments used inner medulla tissue for the RNA isolation. Hybridizations were performed that compared kidney inner medulla total RNA from three control mice against kidney medulla total RNA from 3 mice infused with either arginine vasopressin (AVP) or des-amino-D-arginine vasopressin (dDAVP).
Project description:Vasopressin, the antidiuretic hormone, acts on the renal collecting duct. In this experiment both vasopressin (AVP) and the V2R specific agonist dDAVP were infused into Aquaporin 1 knockout animals for 7 days. The aim of the experiment was to identify genes increased by vasopressin receptors in the renal medullary collecting ducts, in the absence of an increase in renal medullary osmolarity (the AQP1 knockouts are concentrating mechanism knockouts). All experiments used inner medulla tissue for the RNA isolation. Keywords: Vasopressin treatment study
Project description:Activation of ERK1 and ERK2 is essential in regulation of a wide variety of cellular and physiological processes. In native inner medullary collecting ducts, vasopressin (AVP) working through the V2 subtype vasopressin receptor (V2R)-mediated activation of Gαs, inhibits ERK1 and ERK2 activity. However, it has been reported that V2R can signal independently of Gαs through the activation of β-arrestin, which activates ERK1 and ERK2. Vaptans, V2R antagonists that function as so-called “inverse agonists”, have the potential of promoting cell proliferation via β-arrestin-dependent ERK activation. Here we use the mpkCCD cell line which natively expresses V2R to investigate the effects of AVP, the V2-selective analog dDAVP, and tolvaptan on ERK1 and ERK2 phosphorylation and activation. We demonstrated that ERK1 and ERK2 phosphorylation in mpkCCD cells was significantly reduced by either AVP or dDAVP, in contrast to the increases seen in non-collecting duct cells overexpressing V2R. We also found that tolvaptan has a strong effect to increase ERK1 and ERK2 phosphorylation in the presence of dDAVP and that the tolvaptan effect to increase ERK1 and ERK2 phosphorylation is absent in PKA-null mpkCCD cells. Thus, it appears that the tolvaptan effect to increase ERK activation is PKA-dependent and, therefore, not mediated by the β-arrestin pathway. Overall, the studies show that AVP decreases and that tolvaptan increases ERK1 and ERK2 activation in cells expressing V2R at endogenous levels, and provide no evidence for a role for β-arrestin in the regulation of ERK1 and ERK2 activity.
Project description:Activation of ERK1 and ERK2 is essential in regulation of a wide variety of cellular and physiological processes. In native inner medullary collecting ducts, vasopressin (AVP) working through the V2 subtype vasopressin receptor (V2R)-mediated activation of Gαs, inhibits ERK1 and ERK2 activity. However, it has been reported that V2R can signal independently of Gαs through the activation of β-arrestin, which activates ERK1 and ERK2. Vaptans, V2R antagonists that function as so-called “inverse agonists”, have the potential of promoting cell proliferation via β-arrestin-dependent ERK activation. Here we use the mpkCCD cell line which natively expresses V2R to investigate the effects of AVP, the V2-selective analog dDAVP, and tolvaptan on ERK1 and ERK2 phosphorylation and activation. We demonstrated that ERK1 and ERK2 phosphorylation in mpkCCD cells was significantly reduced by either AVP or dDAVP, in contrast to the increases seen in non-collecting duct cells overexpressing V2R. We also found that tolvaptan has a strong effect to increase ERK1 and ERK2 phosphorylation in the presence of dDAVP and that the tolvaptan effect to increase ERK1 and ERK2 phosphorylation is absent in PKA-null mpkCCD cells. Thus, it appears that the tolvaptan effect to increase ERK activation is PKA-dependent and, therefore, not mediated by the β-arrestin pathway. Overall, the studies show that AVP decreases and that tolvaptan increases ERK1 and ERK2 activation in cells expressing V2R at endogenous levels, and provide no evidence for a role for β-arrestin in the regulation of ERK1 and ERK2 activity.
Project description:This series of microarray data contain transcript intensity of mpkCCD cells. Experiment Overall Design: The mpkCCDc14 cells were cloned into colonies with varying aquaporin 2 (AQP2) expression levels in the presence of vasopressin analogy dDAVP. Transcript profiling was done for the original cells and cell clones 2, 3, 9, 10, and 11. By studying transcripts that correlate with AQP2 mRNA levels among cell clones, the objective was to identify transcripts responsible for cell-specific expression of AQP2.
Project description:Activation of the renal urine concentrating mechanism by vasopressin requires the coordinated regulation of multiple gene products including ion transporters, and water channels as well as regulatory proteins like protein kinases and phosphatases or enzymes involved in the energy-metabolism of the cells. We used microarray analysis of AVP-regulated gene products in a rat model of central diabetes insipidus (DI) to generate a comprehensive database documenting these changes. For microarray studies young (8 weeks) adult male Brattleboro rats were randomly divided into 2 groups (n = 3 per group) and treated for 3 days with either 1-desamino-8-D-Arg vasopressin (dDAVP; 5ng/h; Sigma Aldrich, Germany) or vehicle via osmotic minipump (ALZET minipump model 2001, Charles River, Sulzfeld, Germany). At the end of the treatment period animals were sacrificed and the kidneys removed. The outer medulla was isolated and used for cDNA generation and subsequent microarray analysis using [Rat230_2] Affymetrix Rat Genome 230 2.0 Array.
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:Copeptin, the c-terminal fragment of arginine vasopressin (AVP), is considered a useful biomarker for the secretion of AVP. Preeclampsia, a cardiovascular disorder of pregnancy, has been associated with elevated maternal plasma copeptin concentrations. These findings led us to hypothesize that AVP secretion is elevated during preeclampsia, and may contribute to the pathogenesis of this disorder. To examine the effect of increased circulating AVP upon placental development, exogenous AVP was infused into pregnant wildtype C57BL/6J mice, and the transcriptome of a single placenta per dam was assessed at gestational day 12.5 by RNAseq.
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: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.