Neural suppression of miRNA-181a in the kidney elevates renin expression and exacerbates hypertension in Schlager mice

Kristy L. Jackson, Cindy Gueguen, Kyungjoon Lim, Nina Eikelis, Emily R. Stevenson, Fadi J. Charchar, Gavin W. Lambert, Sandra L. Burke, Madeleine R. Paterson, Francine Z. Marques, Geoffrey A. Head

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Abstract

BPH/2J mice are a genetic model of hypertension with overactivity of the sympathetic nervous system (SNS) and renin–angiotensin system (RAS). BPH/2J display higher renal renin mRNA and low levels of its negative regulator microRNA-181a (miR-181a). We hypothesise that high renal SNS activity may reduce miR-181a expression, which contributes to elevated RAS activity and hypertension in BPH/2J. Our aim was to determine whether in vivo administration of a renal-specific miR-181a mimic or whether renal denervation could increase renal miR-181a abundance to reduce renal renin mRNA, RAS activity and hypertension in BPH/2J mice. Blood pressure (BP) in BPH/2J and normotensive BPN/3J mice was measured via radiotelemetry probes. Mice were administered miR-181a mimic or a negative control (1–25 nmol, i.v., n = 6–10) with BP measured for 48 h after each dose or they underwent renal denervation or sham surgery (n = 7–9). Injection of 5–25 nmol miR-181a mimic reduced BP in BPH/2J mice after 36–48 h (−5.3 ± 1.8, −6.1 ± 1.9 mmHg, respectively, P < 0.016). Treatment resulted in lower renal renin and inflammatory marker (TLR4) mRNA levels in BPH/2J. The mimic abolished the hypotensive effect of blocking the RAS with enalaprilat (P < 0.01). No differences between mimic or vehicle were observed in BPN/3J mice except for a higher level of renal angiotensinogen in the mimic-treated mice. Renal miR-181a levels that were lower in sham BPH/2J mice were greater following renal denervation and were thus similar to those of BPN/3J. Our findings suggest that the reduced renal miR-181a may partially contribute to the elevated BP in BPH/2J mice, through an interaction between the renal sympathetic nerves and miR-181a regulation of the RAS.

Original languageEnglish
Number of pages13
JournalHypertension Research
DOIs
Publication statusAccepted/In press - 19 May 2020

Keywords

  • Hypertension
  • MicroRNA
  • Renal denervation
  • Renin–angiotensin system
  • Sympathetic

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