Hypertonicity compromises renal mineralocorticoid receptor signaling through Tis11b-mediated post-transcriptional control.
The mineralocorticoid receptor (MR) mediates the Na(+)-retaining action of aldosterone. MR is highly expressed in the distal nephron, which is submitted to intense variations in extracellular fluid tonicity generated by the corticopapillary gradient. We previously showed that post-transcriptional events control renal MR abundance. Here, we report that hypertonicity increases expression of the mRNA-destabilizing protein Tis11b, a member of the tristetraprolin/ZFP36 family, and thereby, decreases MR expression in renal KC3AC1 cells. The 3'-untranslated regions (3'-UTRs) of human and mouse MR mRNA, containing several highly conserved adenylate/uridylate-rich elements (AREs), were cloned downstream of a reporter gene. Luciferase activities of full-length or truncated MR Luc-3'-UTR mutants decreased drastically when cotransfected with Tis11b plasmid, correlating with an approximately 50% shorter half-life of ARE-containing transcripts. Using site-directed mutagenesis and RNA immunoprecipitation, we identified a crucial ARE motif within the MR 3'-UTR, to which Tis11b must bind for destabilizing activity. Coimmunoprecipitation experiments suggested that endogenous Tis11b physically interacts with MR mRNA in KC3AC1 cells, and Tis11b knockdown prevented hypertonicity-elicited repression of MR. Moreover, hypertonicity blunted aldosterone-stimulated expression of glucocorticoid-induced leucine-zipper protein and the α-subunit of the epithelial Na(+) channel, supporting impaired MR signaling. Challenging the renal osmotic gradient by submitting mice to water deprivation, diuretic administration, or high-Na(+) diet increased renal Tis11b and decreased MR expression, particularly in the cortex, thus establishing a mechanistic pathway for osmotic regulation of MR expression in vivo. Altogether, we uncovered a mechanism by which renal MR expression is regulated through mRNA turnover, a post-transcriptional control that seems physiologically relevant.
Institut National de la Santé et de la Recherche Médicale, U693, Le Kremlin-Bicêtre, France; University of Paris-Sud, Faculté de Médecine Paris-Sud, Unité Mixte de Recherche-S693, Le Kremlin-Bicêtre, France;
Say
S
Viengchareun
Institut National de la Santé et de la Recherche Médicale, U693, Le Kremlin-Bicêtre, France; University of Paris-Sud, Faculté de Médecine Paris-Sud, Unité Mixte de Recherche-S693, Le Kremlin-Bicêtre, France;
Ingrid
I
Lema
Institut National de la Santé et de la Recherche Médicale, U1036, Grenoble, France; Commissariat à l'Energie Atomique, Institute of Life Sciences Research and Technologies, Biology of Cancer and Infection, Grenoble, France; University of Grenoble Alpes, Unité Mixte de Recherche-S1036, Grenoble, France;
Khadija
K
Lamribet
Institut National de la Santé et de la Recherche Médicale, U693, Le Kremlin-Bicêtre, France; University of Paris-Sud, Faculté de Médecine Paris-Sud, Unité Mixte de Recherche-S693, Le Kremlin-Bicêtre, France;
Vixra
V
Keo
Institut National de la Santé et de la Recherche Médicale, Centre d'Investigations Cliniques 9201, Paris, France; and.
Anne
A
Blanchard
Institut National de la Santé et de la Recherche Médicale, U1036, Grenoble, France; Commissariat à l'Energie Atomique, Institute of Life Sciences Research and Technologies, Biology of Cancer and Infection, Grenoble, France; University of Grenoble Alpes, Unité Mixte de Recherche-S1036, Grenoble, France; nadia.cherradi@cea.fr marc.lombes@u-psud.fr.
Nadia
N
Cherradi
Institut National de la Santé et de la Recherche Médicale, U693, Le Kremlin-Bicêtre, France; University of Paris-Sud, Faculté de Médecine Paris-Sud, Unité Mixte de Recherche-S693, Le Kremlin-Bicêtre, France; Assistance Publique-Hôpitaux de Paris, Hôpital de Bicêtre, Service d'Endocrinologie et des Maladies de la Reproduction, Le Kremlin-Bicêtre, France nadia.cherradi@cea.fr marc.lombes@u-psud.fr.
Marc
M
Lombès
D020413:3' Untranslated Regions; D000818:Animals; D051817:Butyrate Response Factor 1 / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D051379:Mice; D009687:Nuclear Proteins / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D016601:RNA-Binding Proteins / Q000378:metabolism*; D018161:Receptors, Mineralocorticoid / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D014868:Water Deprivation; D014883:Water-Electrolyte Imbalance / Q000378:metabolism*
D020413:3' Untranslated Regions; D051817:Butyrate Response Factor 1; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D018161:Receptors, Mineralocorticoid; C102034:ZFP36L1 protein, human; C488431:Zfp36l1 protein, mouse; D012964:Sodium