Acute Aldosterone-mediated Signaling Networks in Distal Convoluted Tubules
Publikation: Bidrag til tidsskrift › Konferenceabstrakt i tidsskrift › fagfællebedømt
The kidney distal convoluted tubule (DCT) plays an important role in modulating body sodium balance and blood pressure. Long-term effects of aldosterone to increase sodium reabsorption in the DCT are well described. However, potential effects of aldosterone to acutely modulate DCT function via non-genomic effects and the signaling cascades responsible remain largely uncharacterized. In mpkDCT cells, 30 min of aldosterone (1nM) caused significant increases in both cellular cAMP and inositol phosphate (IP) levels. RT-PCR and immunohistochemistry identified GPR30 and the EGFR in mpkDCT cells and mouse DCT, providing a possible mechanism for rapid aldosterone effects. 30 min aldosterone treatment resulted in activation of various kinases/kinase substrates in the EGFR/PI3K/AKT or cAMP/PKA pathways. Stable isotope labeling by amino acids in cell culture (SILAC) based quantitative phosphoproteomics was used to map global changes in protein phosphorylation in mpkDCT cells following 30 min aldosterone treatment. A total of 8136 unique proteins, containing 14838 different phosphopeptides were identified. Of these, 148 phosphopeptides were significantly up regulated, and 96 phosphopeptides were downregulated in abundance following aldosterone treatment. The EGFR, ERK1/2, AKT, GSK3B and P70S6K were predicted to be important pathway nodes based on the quantitative proteomics data using network analysis. Ex vivo studies in isolated mouse cortical tubules demonstrated an increase in phosphorylated (active) NCC following 30 mins of aldosterone treatment. In summary, the early effects of aldosterone in the DCT may occur via a GRP30-EGFR pathway to “prime” the DCT cells for future transcriptional and translational regulation, but activation of NCC under similar conditions suggest a novel non-genomic mechanism for aldosterone-mediated alterations in DCT NaCl transport.
|Tidsskrift||F A S E B Journal|
|Status||Udgivet - 2017|