C21 preserves endothelial function in the thoracic aorta from DIO mice: role for AT2, Mas and B2 receptors

Abstract

Compound 21 (C21), a selective agonist of angiotensin II type 2 receptor (AT2R), induces vasodilation through NO release. Since AT2R seems to be overexpressed in obesity, we hypothesize that C21 prevents the development of obesity-related vascular alterations. The main goal of the present study was to assess the effect of C21 on thoracic aorta endothelial function in a model of diet-induced obesity (DIO) and to elucidate the potential cross-talk among AT2R, Mas receptor (MasR) and/or bradykinin type 2 receptor (B2R) in this response. Five-week-old male C57BL6J mice were fed a standard (CHOW) or a high-fat diet (HF) for 6 weeks and treated daily with C21 (1 mg/kg p.o) or vehicle, generating four groups: CHOW-C, CHOW-C21, HF-C, HF-C21. Vascular reactivity experiments were performed in thoracic aorta rings. Human endothelial cells (HECs; EA.hy926) were used to elucidate the signaling pathways, both at receptor and intracellular levels. Arteries from HF mice exhibited increased contractions to Ang II than CHOW mice, effect that was prevented by C21. PD123177, A779 and HOE-140 (AT2R, Mas and B2R antagonists) significantly enhanced Ang II-induced contractions in CHOW but not in HF-C rings, suggesting a lack of functionality of those receptors in obesity. C21 prevented those alterations and favored the formation of AT2R/MasR and MasR/B2R heterodimers. HF mice also exhibited impaired relaxations to acetylcholine (ACh) due to a reduced NO availability. C21 preserved NO release through PKA/p-eNOS and AKT/p-eNOS signaling pathways. In conclusion, C21 favors the interaction among AT2R, MasR and B2R and prevents the development of obesity-induced endothelial dysfunction by stimulating NO release through PKA/p-eNOS and AKT/p-eNOS signaling pathways.

Short‐term dietary intervention improves endothelial dysfunction induced by high‐fat feeding in mice through upregulation of the AMPK‐CREB signaling pathway

“…It is important to note that studies of our group have previously revealed vascular alterations, including endothelial dysfunction and a defective NO release, in mice fed a HF diet for 6 weeks. [17][18][19] The main findings of this study are that restoring a healthy diet for a period as short as 2 weeks after HF diet intake was enough to reduce BW and improve metabolic parameters, endothelial function, and AMPKderived vascular responses in the thoracic aorta, due to the activation of the AMPK/CREB signaling pathway.…”

Angiotensin II type 2 receptor as a novel activator of brown adipose tissue in obesity

“…29,30 In our model, C21-mediated activation of iBAT in HFD-fed mice did not modify body mass, but successfully reduced circulating insulin levels. In addition, previous reports from our group in these animals showed that C21 preserves the endothelial function in thoracic and abdominal aorta from obese mice, 26,27 demonstrating a role in cardiovascular protection. According to our results, C21 enhances BAT activity in obese mice by (i) enhancing thermogenesis via ETC and UCP1 upregulation; (ii) increasing BAT mass through a promotion of cell differentiation, and (iii) improving BAT function through a reduction in inflammation and oxidative stress.…”

“…Potentiating the brown characteristics of PVAT has been proposed to exert protective effects in the aorta 12,42 . In fact, using a similar methodological approach, we have already described the beneficial effects of AT2R activation by C21 in the thoracic aorta of obese animals 43 . C21 prevented the development of obesity‐induced endothelial dysfunction by stimulating NO release through PKA/p‐eNOS and AKT/p‐eNOS pathways.…”

“…12,42 In fact, using a similar methodological approach, we have already described the beneficial effects of AT2R activation by C21 in the thoracic aorta of obese animals. 43 C21 prevented the development of obesity-induced endothelial dysfunction by stimulating NO release through PKA/p-eNOS and AKT/p-eNOS pathways. However, in light of the results presented in the current report, we should not discard the contribution of the enhanced activity of tPVAT.…”

“…The vascular effects of this experimental approach have been previously reported in Gonz alez-Bl azquez et al 26,27 The experimental procedures were performed in accordance with the European Union Laboratory Animal Care Rules (86/609/ECC directive) and approved by the Ethical Committee of the San Pablo CEU University and the Animal Protection Area of the Comunidad Aut onoma de Madrid (PROEX 200/18).…”