Gene Trapping Uncovers Sex-Specific Mechanisms for Upstream Stimulatory Factors 1 and 2 in Angiotensinogen Expression

Abstract

A single-nucleotide polymorphism (C/A) located within an E-box at the −20 position of the human angiotensinogen (AGT) promoter may regulate transcriptional activation through differential recruitment of the transcription factors Upstream Stimulatory Factor (USF) 1 and 2. To study the contribution of USF1 on AGT gene expression, mice carrying a (−20C) human AGT transgene were bred with mice harboring a USF1 gene trap allele designed to knock down USF1 expression. USF1 mRNA was reduced relative to controls in liver (9±1%), perigenital adipose (16±3%), kidney (17±1%), and brain (34±2%) in double-transgenic mice. This decrease was confirmed by electrophoretic mobility shift assay. Chromatin immunoprecipitation (ChIP) analyses revealed a decrease in USF1, with retention of USF2 binding at the human AGT promoter in the liver of male mice. Human AGT expression was reduced in the liver and other tissues of female but not male mice. The decrease in endogenous AGT expression was insufficient to alter systolic blood pressure at baseline, but caused reduced systolic blood pressure in female USF1 gene trap mice fed a high fat diet. Treatment of USF1 knockdown males with intravenous adenoviral shRNA targeting USF2 resulted in reduced expression of USF1, USF2 and human AGT protein. Our data from ChIP assays suggests that this decrease in human AGT is due to decreased USF2 binding to the human AGT promoter. In conclusion, both USF1 and USF2 are essential for AGT transcriptional regulation, and distinct gender-specific and tissue-specific mechanisms are involved in the activities of these transcription factors in vivo.

Polymorphism in miR-31 and miR-584 binding site in the angiotensinogen gene differentially influences body fat distribution in both sexes

“…This pattern may be partially attributed to local differences in angiotensinogen production by adipocytes (Dusserre et al 2000;Van Harmelen et al 2000a, b), which is suppressed by miR-31 and/or miR-584 in C allele homozygotes but not in A allele carriers. Such sex-specific differences in angiotensinogen expression have been confirmed in the case of AGT promoter polymorphism -20 C/A (rs5050) when transgenic mice producing human AGT was used (Park et al 2012). Interestingly, these differences were also depot specific with differences between omental and perigenital fatty tissue.…”

Sex differences in depressive, anxious behaviors and hippocampal transcript levels in a genetic rat model

“…The functions of Dhx36 and Psmc6 with female‐ and male‐specific strain differences, respectively, have not yet been investigated in the brain. Usf1 , which showed female‐specific strain differences in adulthood, has been shown to regulate angiotensinogen expression with consequences in females only (Park et al ). Furthermore, polymorphisms in Usf1 have been associated with neuropathological lesions in Alzheimer's disease (Isotalo et al ).…”

Allele-Specific Expression of Angiotensinogen in Human Subcutaneous Adipose Tissue

“…15 Similarly, we showed that AGT expression in many tissues was decreased in USF1-deficient mice. 16 …”

“…14 Both USF1 and USF2 are essential for AGT transcriptional regulation 15 , and gender-specific mechanisms are involved in their activity on AGT expression in vivo . 16 USF1 polymorphisms were reported to be associated with the level of AGT expression in human fat biopsies. 17 AGT expression in the renal medulla was reported to be higher in subjects carrying the −20C allele than the −20A.…”