Human Soluble Prorenin Receptor Expressed in Adipose Tissue Improves Insulin Sensitivity and Endothelial Function in Obese Female Mice
Authors: Arthur Gertrude , Ahmed Nermin , Loria Analia 
Published: May 2024

Increased circulating levels of the soluble prorenin receptor (sPRR), a component of the renin angiotensin system (RAS), plays a role in obesity, glucose, and insulin balance. Additionally, studies show that elevated plasma sPRR in diabetic patients is correlated with hyperglycemia in women but not men. Hence, the current study sought to understand the functional role of circulating human sPRR (HsPRR) produced by the adipose tissue (Adi) on adipogenesis and obesity, glucose homeostasis and insulin sensitivity. Adi-HsPRR mice were generated by breeding human sPRR-Myc-tag transgenic mice with mice expressing Adiponectin/Cre. The mouse model was validated by detecting myc-tagged HsPRR in western blot at 28kD. Adi-HsPRR male and female mice were kept on a low-fat (10% kcal from fat; n=4-9/group) or high-fat diet (60% kcal from fat; n=8-13/group) for 20 weeks. Body weight was recorded weekly and body composition (EchoMRI) was assessed monthly. Intraperitoneal glucose tolerance test (ipGTT) was performed at 12 weeks and insulin tolerance test (ITT) at 14 weeks. At 16 weeks, mice were implanted with radio telemeter to measure blood for 5 consecutive days. At the end of the study, tissues and plasma were collected for biochemical analysis and vascular studies. Adipose HsPRR expression did not change circulating sPRR between groups in mice fed a low-fat diet mouse (M: 3.5±0.5 vs 3.9±0.2 ng/ml, F: 2.3±0.2 vs 3.0±0.2 ng/ml) and high fat-fed females (4.3±0.3 vs 5.4±0.5 ng/ml) but increased plasma sPRR in HFD Adi-HsPRR male mice compared to HFD CTL (5.3±0.4 vs 8.7±0.7 ng/ml p<0.05). Yet, Adi-HsPRR expression did not change body weight and composition, glucose, and insulin balance, nor blood pressure and vascular function in male mice regardless the diet. However, Adi-HsPRR improved insulin sensitivity (438±22 vs 360±14 AUC p<0.05) and endothelium-dependent vascular relaxation (11.7±2.6 vs 19.4±2.5 % p<0.05) in Adi-HsPRR female mice fed an HFD. Blood pressure was similar between groups in males and females on both LFD and HFD. Further analysis showed that Adi-HsPRR increased vasodilator agent, Ang 1-7 (5.1±1.6 vs 16.2±3.0 pmol/L p<0.05) in HFD females which was unchanged in HFD males (10.2±2.4 vs 5.2±1.7 pmol/L). Moreover, Adi-HsPRR reduced gene expression of SREBP1C (1.3±0.2 vs 0.7±0.1 2−ΔΔCT p<0.05) and CD36 (1.5±0.3 vs 0.6±0.1 2−ΔΔCT p<0.05), in gonadal white adipose of HFD females but not in males. Additionally, PPAR gamma mRNA was reduced in HFD Adi-HsPRR females (1.1±0.1 vs 0.6±0.1 2−ΔΔCT p<0.05). Our findings suggest that HsPRR in adipose tissue exerts sex-specific protective effects on insulin sensitivity and endothelial function during obesity, despite similar plasma sPRR levels between control and Adi-HsPRR mice. Thus, our model could be a useful tool to investigate potential antidiabetic effect of adipose sPRR in obese women. This work was supported by National Institutes of Health grants (R01-HL-142969 and R01-HL-1647 to ASL); the National Institute of General Medical Sciences (P30 GM127211); and the University of Kentucky, Center for Clinical and Translational Sciences (UL1TR001998). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.