Differential modulation of uncoupling protein 2 in kidneys of stroke-prone spontaneously hypertensive rats under high-salt/low-potassium diet

Sara Di Castro, Stefania Scarpino, Simona Marchitti, Franca Bianchi, Rosita Stanzione, Maria Cotugno, Luigi Sironi, Paolo Gelosa, Enrico Duranti, Luigi Ruco, Massimo Volpe, Speranza Rubattu

Research output: Contribution to journalArticlepeer-review

Abstract

The stroke-prone spontaneously hypertensive rat (SHRsp) represents an animal model of increased susceptibility to high-salt diet-induced cerebral and renal vascular injuries. High blood pressure and genetic factors are viewed as major contributing factors. In high-salt-loaded SHRsp and stroke-resistant SHR animals, we determined blood pressure levels, degree of kidney lesions, renal uncoupling protein 2 (UCP2) gene and protein expression levels along with rattus norvegicus (rno)-microRNA (miR) 24 and 34a gene expression, nuclear factor-κB protein levels, and oxidative stress. In vitro, UCP2 gene silencing was performed in renal mesangial cells. We found more severe degree of renal damage in SHRsp at the end of 4-week high-salt dietary treatment as compared with stroke-resistant SHR, despite comparable blood pressure levels, along with increased rate of inflammation and oxidative stress. Kidney UCP2 gene and protein expression levels were significantly downregulated under high-salt diet in SHRsp, but not in stroke-resistant SHR. Differential UCP2 regulation was paralleled by differential expression of kidney rno-miR 24 and 34a, known to target UCP2 gene, in the 2 strains. UCP2 gene silencing in renal mesangial cells led to increased rate of reactive oxygen species generation, increased inflammation and apoptosis, reduced cell vitality, and increased necrosis. In conclusion, high-salt diet downregulates the antioxidant UCP2-dependent mechanism in kidneys of SHRsp, but not of stroke-resistant SHR. A parallel differential kidney miR regulation under high-salt diet in the 2 strains may contribute to the differential UCP2 modulation. UCP2 is a critical protein to prevent oxidative stress damage in renal mesangial cells in vitro.

Original languageEnglish
Pages (from-to)534-541
Number of pages8
JournalHypertension
Volume61
Issue number2
DOIs
Publication statusPublished - Feb 2013

Keywords

  • hypertensive renal damage
  • miRNA
  • oxidative stress
  • salt loading
  • SHRsp
  • UCP2

ASJC Scopus subject areas

  • Internal Medicine

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