Abstract: SA-PO1105

Identification of an miRNA That Regulates Sodium-Hydrogen Antiporter 1 Expression in the Medullary Thick Ascending Limb of a High Sodium Induced Hypertension Rat Model

Session Information

  • Salt and Hypertension
    November 04, 2017 | Location: Hall H, Morial Convention Center
    Abstract Time: 10:00 AM - 10:00 AM

Category: Hypertension

  • 1104 Hypertension: Clinical and Translational - Salt and Hypertension

Authors

  • Lombari, Patrizia, Università degli studi della Campania, Naples, Italy
  • Mallardo, Massimo, Università degli studi di Napoli "Federico II", Naples, Italy
  • Nagoth, Joseph amruthraj, Università degli studi della Campania, Naples, Italy
  • Patrazzuolo, Oriana, Università degli studi della Campania, Naples, Italy
  • Fiume, Giuseppe, Università degli Studi di Catanzaro ?Magna Graecia?, Catanzaro, Italy
  • Damiano, Sara, Università degli studi della Campania, Naples, Italy
  • Ingrosso, Diego, Università degli studi della Campania "L. Vanvitelli", Naples, Italy
  • Iervolino, Anna, University of Campania Luigi Vanvitelli, Napoli, Italy
  • Capasso, Giovambattista, University of Campania Luigi Vanvitelli, Napoli, Italy
Background

The kidney is one of the principle candidate organs involved in the etiology of essential hypertension. In particular, the medullary thick ascending limb (MTAL) of kidney is important in maintaining acid-base balance by reabsorbing most of the filtered bicarbonate, which is not reabsorbed by the proximal tubule. Microarray expression profiling studies in human revealed different expression profiles of microRNAs in hypertensive vs normotensive patients.
In this study, we analyzed miRNA expression profiles in isolated MTAL taken from high sodium intake induced hypertensive rats (HSD) versus their normotensive counter parts (NSD).

Methods

Male Sprague Dawley rats weighing about 185-298 g (Charles river) were allowed free access to standard rodent chow (NIH 31 diet, Ziegler Bros., Gardeners, PA) and drinking solution up to the time of experiments. Control rats were fed with normal drinking water (NSD) and rats on HS-in were fed with 0.28 M NaCl in drinking water (HSD) for 15 days.
Renal tubule isolation was performed following method described on Hofmeister, M. V. et al ( Am J Physiol Renal Physiol 2009; 296:F194-203)
and the total RNAs was analyzed by genome-wide miRNAs expression profile in MTAL dissected from rats upon HSD or NSD

Results

We have identified seven miRNAs, involved in the onset of salt sensitive hypertension, among them one was the most strongly down-regulated. We identified the sodium-hydrogen antiporter 1 (NHE1) mRNA as a putative target of this miRNA, by in silico analysis. Our data showed that this miRNA is downregulated in the MTAL of HSD rats while NHE1 is upregulated, we also checked whether the levels of protein NHE1 could be lowered by overexpression of the identified miRNA. To verify this hypothesis we overexpressed this miRNA in MTAL cell line, by retroviral infection, and observed a downregulation of NHE1 protein.

Conclusion

Our result indicate NHE1 as a target of the identified miRNA and that the expression of this miRNA is influenced by high sodium intake in thick ascending limbs of rats.