Variable Transcriptional Regulation of the Human Aldosterone Synthase Gene Causes Salt-Dependent High Blood Pressure in Transgenic Mice Article (Web of Science)

abstract

  • Background— Aldosterone, synthesized in the adrenal cortex by the enzyme CYP11B2, induces positive sodium balance and predisposes to hypertension. Various investigators, using genomic DNA analyses, have linked -344T polymorphism in the human CYP11B2 (h CYP11B2 ) gene to human hypertension. h CYP11B2 gene promoter has 3 single-nucleotide polymorphisms in linkage disequilibrium: T/A at -663, T/C at -470, and C/T at -344. Variants ACT occur together and form the haplotype-I (Hap-I), whereas variants TTC constitute Hap-II. We hypothesize that these single-nucleotide polymorphisms, when present together, will lead to haplotype-dependent differences in the transcriptional regulation of the h CYP11B2 gene and affect blood pressure regulation. Methods and Results— We evaluated differences in tissue expression in vivo and consequential effects on blood pressure stemming from the 2 haplotypes. Novel transgenic mice with the h CYP11B2 gene, targeted to the mouse HPRT locus, with either Hap-II or Hap-I variant are used in this study. Our results show increased adrenal and renal expression of h CYP11B2 in transgenic mice with Hap-I when compared with mice with Hap-II. Importantly, we observed increased baseline blood pressure in Hap-I transgenic mice, an effect accentuated by a high-salt diet. Pathophysiological effects of elevated aldosterone were corroborated by our results showing upregulation of proinflammatory markers in renal tissues from the transgenic mice with Hap-I. Conclusions— These findings characterize the haplotype-dependent regulation of the h CYP11B2 gene where -344T serves as a reporter polymorphism and show that Hap-I leads to increased expression of h CYP11B2 , with permissive effects on blood pressure and inflammatory milieu.

authors

  • Mopidevi, Brahmaraju
  • Kaw, Meenakshi K.
  • Puri, Nitin
  • Ponnala, Madhusudan
  • Jain, Sudhir
  • Rana, Anita
  • Keetha, Narsimha R.
  • Khuder, Sadik A
  • Fiering, Steven N.
  • Kumar, Ashok

publication date

  • 2015

webpage

published in

number of pages

  • 9

start page

  • 30

end page

  • 39

volume

  • 8

issue

  • 1