Signal Transduction Profiling of Angiotensin II Type 1 Receptor With Mutations Associated to Atrial Fibrillation in Humans

Abstract

The AT1 receptor (AT1R) has a major role in the Renin-Angiotensin System, being involved in several physiological events including blood pressure control and electrolyte balance. The AT1R is a member of the G protein coupled receptors (GPCR) family, classically known to couple Gαq and engage β-arrestin recruitment. Both G protein and arrestin signaling pathways are involved in modulation of different downstream kinases. A previous study reported that mutations in the AT1R (A244S and I103T-A244S) were positively correlated with higher risk of atrial fibrillation in men. Based on that report, we aimed to investigate if these mutations, including I103T only, could affect AT1R signal transduction profile, and consequently, implicate in atrial fibrillation outcome. To address that, we engineered an AT1R carrying the above-mentioned mutations, and functionally evaluated different signaling pathways. Phosphokinase profiler array to assess the mutations downstream effects on kinases and kinase substrates phosphorylation levels was used. Our results show that the I103T-A244S mutant receptor presents decreased β-arrestin 2 recruitment, which could lead to a harmful condition of sustained Gαq signaling. Moreover, the phosphokinase profiler array revealed that the same mutation led to downstream modulation of kinase pathways that are linked to physiological responses such as fibrous tissue formation, apoptosis and cell proliferation.

Angiotensin II Type I Receptor (AT1R): The Gate towards COVID-19-Associated Diseases

“…In fact, most Ang II physiological effects are mediated through AT1R [ 14 ]. AT1R is a GPCR that requires Ang II binding for its activation [ 14 , 15 , 25 ]. Therefore, it belongs to the canonical seven-transmembrane α-helical superfamily, with an intracellular C-terminal domain, an extracellular N-terminal domain, three intracellular loops (ICL1, ICL 2, ICL3), an amphipathic helix VIII, and three extracellular loops (ECL1, ECL2, ECL3) [ 13 , 14 , 26 ].…”

“…Polymorphisms in GPCRs were shown to be associated with different phenotypes and to predispose to certain types of diseases [ 15 ]. More than 700 mutations, that can overactivate or inactivate the receptors, have been identified and linked to more than 30 distinct human illnesses [ 15 ].…”

“…Polymorphisms in GPCRs were shown to be associated with different phenotypes and to predispose to certain types of diseases [ 15 ]. More than 700 mutations, that can overactivate or inactivate the receptors, have been identified and linked to more than 30 distinct human illnesses [ 15 ]. Minor information about AT1R polymorphisms in SARS-CoV-2 patients is found, despite their importance as risk factors in COVID-19 such as those implicated in diabetes, hypertension, and cardiovascular diseases (CVDs) [ 28 ].…”

“…The physiological effects of Ang II are mediated mainly by AT1R and Ang II type 2 receptor (AT2R) [ 12 , 13 , 14 ]. AT1R effects include control of blood pressure, contraction of blood vessels, electrolyte balance, aldosterone synthesis and release from the adrenal cortex [ 15 , 16 ]. Furthermore, each receptor transmits opposing effects, with AT1R mediating vasoconstriction, proliferation, fibrosis, and inflammation and AT2R mediating vasodilation, antifibrosis, and anti-inflammation ( Figure 1 ) [ 12 , 14 ].…”

Relevance of Peptide Homeostasis in Metabolic Retinal Degenerative Disorders: Curative Potential in Genetically Modified Mice

“…The release of Ang II is generally known to induce vasoconstriction, thirst and the release of aldosterone ( Culman et al, 1995 ) and has also been demonstrated to possess pro-inflammatory effects ( Ruiz-Ortega et al, 2001 ; Chen et al, 2006 ; Ruiz-Ortega et al, 2006 ; Wilkinson-Berka et al, 2019 ), which are all conveyed through the angiotensin II type 1 receptor (AT1R; Forrester et al, 2018 ). AT1 receptors are G-protein coupled receptors that ultimately trigger the release of Ca 2+ from the endoplasmic reticulum which results in the activation of protein kinase C (PKC) and additional kinase enzyme activation in the extracellular signal-regulated kinase (ERK1/2) pathway ( Simões et al, 2020 ). In contrast, the type 2 receptor (AT2R) is generally understood to act against AT1R, as it is known to elicit vasodilation through the generation of nitric oxide (NO) and contribute to cell survival ( Reinecke et al, 2003 ; Carey, 2017 ; Verma et al, 2019 ).…”