The Angiotensin-(1-7)/Mas Axis Counteracts Angiotensin II-Dependent and -Independent Pro-inflammatory Signaling in Human Vascular Smooth Muscle Cells

Abstract

Background and Aims: Targeting inflammation is nowadays considered as a challenging pharmacological strategy to prevent or delay the development of vascular diseases. Angiotensin-(1-7) is a member of the renin-angiotensin system (RAS) that binds Mas receptors and has gained growing attention in the last years as a regulator of vascular homeostasis. Here, we explored the capacity of Ang-(1-7) to counteract human aortic smooth muscle cell (HASMC) inflammation triggered by RAS-dependent and -independent stimuli, such as Ang II or interleukin (IL)-1β.Methods and Results: In cultured HASMC, the expression of inducible nitric oxide synthase (iNOS) and the release of nitric oxide were stimulated by both Ang II and IL-1β, as determined by Western blot and indirect immunofluorescence or the Griess method, respectively. iNOS induction was inhibited by Ang-(1-7) in a concentration-dependent manner. This effect was equally blocked by two different Mas receptor antagonists, A779 and D-Pro7-Ang-(1-7), suggesting the participation of a unique Mas receptor subtype. Using pharmacological inhibitors, the induction of iNOS was proven to rely on the consecutive upstream activation of NADPH oxidase and nuclear factor (NF)-κB. Indeed, Ang-(1-7) markedly inhibited the activation of the NADPH oxidase and subsequently of NF-κB, as determined by lucigenin-derived chemiluminescence and electromobility shift assay, respectively.Conclusion: Ang-(1-7) can act as a counter-regulator of the inflammation of vascular smooth muscle cells triggered by Ang II, but also by other stimuli beyond the RAS. Activating or mimicking the Ang-(1-7)/Mas axis may represent a pharmacological opportunity to attenuate the pro-inflammatory environment that promotes and sustains the development of vascular diseases.

The angiotensin‐(1‐7)/Mas receptor axis protects from endothelial cell senescence via klotho and Nrf2 activation

“…Ang‐(1‐7) also mitigates SA‐β‐gal activity, which reflects the increased lysosomal mass observed in senescent cells (Kurz, Decary, Hong, & Erusalimsky, ), and attenuates the SASP that promotes leukocyte adhesion and inflammation. All these anti‐senescence actions of Ang‐(1‐7) relied on the activation of the Mas receptors, as for other vascular and non‐vascular protective actions of Ang‐(1‐7) (Machado‐Silva et al, ; Peiró et al, ; Villalobos et al, ). In line with our findings, a recent microarray‐based study has identified the senescence‐associated p53 signaling pathway as a main protein cluster influenced by Ang‐(1‐7) in endothelial cells (Meinert et al, ).…”

“…DNA damage foci and telomere dysfunction‐induced foci (TIFs) were examined by immunofluorescence microscopy as previously described (Cardus et al, 2013; Villalobos et al, ). Telomeres were detected with an anti‐telomere repeat binding factor‐1 (TRF‐1) mouse monoclonal antibody (clone TRF‐78, dilution 1/1,000; Abcam) followed by a goat anti‐mouse IgG Alexa Fluor conjugate (dilution 1/1,000; Invitrogen, Paisley, UK).…”

“…Nrf2 was visualized in HUVEC by indirect immunofluorescence as previously described (Villalobos et al, ). A primary polyclonal antibody against Nrf2 (dilution 1/500; H‐300, SC‐13032, Santa Cruz Biotechnology) was used, followed by incubation with an appropriate secondary antibody (dilution 1/800).…”

“…In the cardiovascular system, Ang‐(1‐7) has been regarded as a physiological antagonist of Ang II by opposing its vasoconstrictor, proliferative, hypertrophic, or pro‐inflammatory actions (Machado‐Silva, Passos‐Silva, Santos, & Sinisterra, ; Peiró et al, ; Simões E Silva & Teixeira, ; Villalobos et al, ). In recent studies, Ang II has been shown to directly promote endothelial cell senescence, thus contributing to vascular disease by a novel mechanism (Hsu, Lin, Lin, & Juo, ; Li et al, ).…”

The Human-Covid Tango: Connecting the Dots

“…Although the exact mechanisms of this antiinflammatory effect is not fully understood, it could involve numerous components of the inflammatory cascade. For example, reductions of NFκB-related signaling (Yu et al,2018), transforming growth factor (TGF)-β (Chappell & Al Zayadneh, 2017;Chou et al,2013) and cytokine modulation (Villalobos et al, 2016) have all been seen. Infusions of Ang 1-7 in lung injury models protected the lungs from acute lung lesions and decreased lung edema (Klein et al, 2013), which can be crucial for Covid-19 patients.…”