Intracerebroventricular Administration of AT1 Receptor Antisense Oligonucleotides Inhibits the Behavioral Actions of Angiotensin II

Abstract: Antisense Oligonucleotides were developed to study the expression and function of angiotensin type 1 (AT₁) receptors in cultured cells and brain. In both liver epithelial WB and neuro-blastoma N1E-115 cells AT₁ antisense oligomers substantially decreased AT₁ receptor density, whereas angiotensin type 2 (AT₂) receptors remained unchanged. Similarly, repeated intracerebroventricular injections of AT₁ antisense oligomers in rats decreased AT₁ receptor density in hypothalamic-thalamic-septal tissue, and AT₂ receptors were unaffected. Intracerebroventricular antisense oligomers also attenuated drinking elicited by intra-cerebroventricular angiotensin II but not the cholinomimetic carbachol. Collectively, these results demonstrate that antisense Oligonucleotides attenuate angiotensin receptor expression and function in behaving animals.     

New insights and perspectives on intrarenal renin-angiotensin system: focus on intracrine/intracellular angiotensin II

Although renin, the rate-limiting enzyme of the renin-angiotensin system (RAS), was first discovered by Robert Tigerstedt and Bergman more than a century ago, the research on the RAS still remains stronger than ever. The RAS, once considered to be an endocrine system, is now widely recognized as dual (circulating and local/tissue) or multiple hormonal systems (endocrine, paracrine and intracrine). In addition to the classical renin/angiotensin I-converting enzyme (ACE)/angiotensin II (Ang II)/Ang II receptor (AT₁/AT₂) axis, the prorenin/(Pro)renin receptor (PRR)/MAP kinase axis, the ACE2/Ang (1-7)/Mas receptor axis, and the Ang IV/AT₄/insulin-regulated aminopeptidase (IRAP) axis have recently been discovered. Furthermore, the roles of the evolving RAS have been extended far beyond blood pressure control, aldosterone synthesis, and body fluid and electrolyte homeostasis. Indeed, novel actions and underlying signaling mechanisms for each member of the RAS in physiology and diseases are continuously uncovered. However, many challenges still remain in the RAS research field despite of more than one century's research effort. It is expected that the research on the expanded RAS will continue to play a prominent role in cardiovascular, renal and hypertension research. The purpose of this article is to review the progress recently being made in the RAS research, with special emphasis on the local RAS in the kidney and the newly discovered prorenin/PRR/MAP kinase axis, the ACE2/Ang (1-7)/Mas receptor axis, the Ang IV/AT₄/IRAP axis, and intracrine/intracellular Ang II. The improved knowledge of the expanded RAS will help us better understand how the classical renin/ACE/Ang II/AT₁ receptor axis, extracellular and/or intracellular origin, interacts with other novel RAS axes to regulate blood pressure and cardiovascular and kidney function in both physiological and diseased states.     

Stable expression of a functional rat angiotensin II (AT1A) receptor in CHO-K1 cells: Rapid desensitization by angiotensin II

The octapeptide angiotensin II mediates the physiological actions of the renin-angiotensin system through activation of several angiotensin II receptor subtypes; in particular the AT₁. In many tissues, the presence of multiple angiotensin II receptor subtypes, together with a low number of receptors, makes it difficult to study biological responses to physiological concentrations (10^–11–10^–9 M) of angiotensin II. Also, cultured cells show diminished angiotensin II receptor binding with respect to time in culture and passage number. To address these problems, we expressed the recombinant AT_1A receptor in CHO-K1 cells. The stably transfected receptor was characterized using radioligand binding studies and functional coupling to cytosolic free calcium. Radioligand binding of [¹²⁵I] angiotensin II to the angiotensin II receptor was specific, saturable, reversible and modulated by guanine nucleotides. Like the endogenous AT_1A receptor, reported in a variety of tissues, the specific, noncompetitive, nonpeptide AII receptor antagonist, EXP3174, blocked binding of [¹²⁵I] angiotensin II to the transfected receptor. Scatchard analysis demonstrated that the transfected receptor had a dissociation constant of 1.9 nM with a density of 3.4 pmol/mg protein.An important feature of many of the responses to angiotensin II is the rapid desensitization that occurs following agonist occupancy and the development of tachyphylaxis. In AT_1A receptor transfected CHO-K1 cells, angiotensin II (10^–9 M) stimulated a rapid increase in cytosolic free calcium that was completely desensitized within 50 sec following receptor occupancy. Agonist induced desensitization was unaffected when receptor internalization was blocked by pretreatment with concanavalin A or incubation at 4°C, and no changes in AT_1A receptor affinity or number were observed. Receptor desensitization was also unaffected by inhibition or activation of protein kinase C. Thus, we have established a permanent, high-level transfectant of the AT_1A receptor in CHO-K1 cells and have shown that these receptors rapidly desensitize following exposure to physiological concentrations of agonist. The mechanism of rapid desensitization is not related to receptor sequestration, internalization or controlled by PKC phosphorylation. This provides an excellent model for studying AII actions mediated through a specific receptor subtype, at subnanomolar concentrations.     

Characterization of AT2 Receptor Expression in NIH 3T3 Fibroblasts

1. A high expression of angiotensin II receptors and of angiotensin-converting enzyme (ACE) activity was detected in confluent NIH 3T3 fibroblasts.2. Characterization with selective ligands, dithiothreitol, and GTPS, indicated that only the AT₂ subtype was expressed.3. AT₂ receptors and ACE expression were strictly dependent on the cell density and growth phase of the cells, with AT₂ receptors being expressed earlier than ACE. In contrast, high expression of AT₂ receptors irrespective of their growth state was observed in NIH 3T3 cells lacking contact inhibition upon neoplastic transformation with ras.4. Our results imply a possible relation of AT₂ receptors to cell growth and cell–cell contact.     

Beneficial Effects of the Activation of the Angiotensin-(1–7) Mas Receptor in a Murine Model of Adriamycin-Induced Nephropathy

Angiotensin-(1–7) [Ang-(1–7)] is a biologically active heptapeptide that may counterbalance the physiological actions of angiotensin II (Ang II) within the renin-angiotensin system (RAS). Here, we evaluated whether activation of the Mas receptor with the oral agonist, AVE 0991, would have renoprotective effects in a model of adriamycin (ADR)-induced nephropathy. We also evaluated whether the Mas receptor contributed for the protective effects of treatment with AT₁ receptor blockers. ADR (10 mg/kg) induced significant renal injury and dysfunction that was maximal at day 14 after injection. Treatment with the Mas receptor agonist AVE 0991 improved renal function parameters, reduced urinary protein loss and attenuated histological changes. Renoprotection was associated with reduction in urinary levels of TGF-β. Similar renoprotection was observed after treatment with the AT₁ receptor antagonist, Losartan. AT₁ and Mas receptor mRNA levels dropped after ADR administration and treatment with losartan reestablished the expression of Mas receptor and increased the expression of ACE2. ADR-induced nephropathy was similar in wild type (Mas^+/+) and Mas knockout (Mas ^−/−) mice, suggesting there was no endogenous role for Mas receptor activation. However, treatment with Losartan was able to reduce renal injury only in Mas^+/+, but not in Mas ^−/− mice. Therefore, these findings suggest that exogenous activation of the Mas receptor protects from ADR-induced nephropathy and contributes to the beneficial effects of AT₁ receptor blockade. Medications which target specifically the ACE2/Ang-(1–7)/Mas axis may offer new therapeutic opportunities to treat human nephropathies.     

Involvement of AT(1) angiotensin receptors in the vasomodulatory effect of des-aspartate-angiotensin I in the rat renal vasculature

Angiotensin II is known to act primarily on the angiotensin AT(1) receptors to mediate its physiological and pathological actions. Des-aspartate-angiotensin I (DAA-I) is a bioactive angiotensin peptide and have been shown to have contrasting vascular actions to angiotensin II. Previous work in this laboratory has demonstrated an overwhelming vasodepressor modulation on angiotensin II-induced vasoconstriction by DAA-I. The present study investigated the involvement of the AT(1) receptor in the actions of DAA-I on angiotensin II-induced vascular actions in the renal vasculature of normotensive Wistar-Kyoto rats (WKY), spontaneously hypertensive rats (SHR) and streptozotocin (STZ)-induced diabetic rats. The findings revealed that the angiotensin receptor in rat kidney homogenate was mainly of the AT(1) subtype. The AT(1) receptor density was significantly higher in the kidney of the SHR. The increase in AT(1) receptor density was also confirmed by RT-PCR and Western blot analysis. In contrast, AT(1) receptor density was significantly reduced in the kidney of the streptozotocin-induced diabetic rat. Perfusion with 10(-9)M DAA-I reduced the AT(1) receptor density in the kidneys of WKY and SHR rats suggesting that the previously observed vasodepressor modulation of the nonapeptide could be due to down-regulation or internalization of AT(1) receptors. RT-PCR and Western blot analysis showed no significant changes in the content of AT(1) receptor mRNA and protein. This supports the suggestion that DAA-I causes internalization of AT(1) receptors. In the streptozotocin-induced diabetic rat, no significant changes in renal AT(1) receptor density and expression were seen when its kidneys were similarly perfused with DAA-I.     

The inhibitory effects of rosiglitazone on cardiac hypertrophy through modulating the renin‐angiotensin system in diet‐induced hypercholesterolemic rats

Cardiac hypertrophy is not only an adaptational state before heart failure but also is an independent risk factor for ischemia, arrhythmia, and sudden death. However, the direct effects of hypercholesterolemia on the myocardium and mechanisms are not completely understood. It has been demonstrated that peroxisome proliferator‐activated receptor‐γ (PPARγ) ligand agonists attenuate cardiac hypertrophy through anti‐inflammatory effects. The present study investigated the effects of PPARγ agonists on hypercholesterolemia‐dependent, renin‐angiotensin‐system‐related cardiac hypertrophy. The findings showed that left ventricular hypertrophy, eminent cardiomyocyte hypertrophy, and lipid deposits in myocardium were observed in the rats fed a cholesterol‐rich diet for 6 months, while these characteristic pathological alterations and the increase in angiotensin II (ANG II) level and over‐expression of angiotensin II type 1 receptor (AT₁R) in the left ventricular tissues induced by the cholesterol‐rich diet were significantly suppressed to equal extents by rosiglitazone and irbesartan. In contrast, expression of angiotensin II type 2 receptor (AT₂R) was upregulated by these two drugs. In addition, lipid metabolism was markedly improved. The above findings suggest that the cardioprotection of the PPARγ agonist against cardiac hypertrophy evoked by hypercholesterolemia in rats is mediated partially by the improvement of lipid profile, the reduction of ANG II level in the local tissue along with the downregulation of AT₁R expression, and upregulation of AT₂R expression. Copyright © 2009 John Wiley & Sons, Ltd.     

Co-operative effects of angiotensin II and caerulein in NFκB activation in pancreatic acinar cells in vitro

Angiotensin II is a vasoactive peptide that controls blood pressure and homeostasis. Emerging evidence shows that locally generated angiotensin II plays a crucial role in normal physiology, as well as pathophysiological conditions such as pancreatitis. We recently reported that angiotensin II activates pancreatic NFκB in obstructive pancreatitis. However, the specific cell type responsible for this activation remains unclear. In this study, we investigated whether pancreatic acinar cells respond to angiotensin II. These cells are the most abundant pancreatic cells and the most vulnerable to pancreatitis. Pancreatic acinar AR42J cells were used as an in vitro model of pancreatic inflammation. Our results demonstrated that treatment with caerulein, a cholecystokinin receptor agonist, induced hypersecretion and NFκB activation, as demonstrated by elevated amylase secretion and degradation of inhibitor of NFκB (IκBβ). Angiotensin II, either alone or in combination with caerulein, augmented IκBβ degradation. Pre-treatment with losartan, an antagonist of the angiotensin type I (AT₁) receptor, abolished NFκB activation by angiotensin II and caerulein in a dose-dependent manner. Treatment with PD123319, a blocker of the angiotensin type II (AT₂) receptor, enhanced the activation of NFκB by angiotensin II and caerulein. Preliminary data further demonstrated that angiotensin II could extend caerulein-induced ERK1/2 activation in acinar cells. These results indicated that inflammation triggered by hyperstimulation of pancreatic acinar cells is enhanced by angiotensin II, via the AT₁ receptor. In contrast, stimulation of the AT₂ receptor protects against caerulein-induced NFκB activation. The differential roles of the AT₁ and AT₂ receptors might be useful in developing potential therapies for pancreatic inflammation.     

Dissecting the cosubstrate structure requirements of the Staphylococcus aureus aminoglycoside resistance enzyme ANT(4')

Although angiotensin II (Ang II) binds to Ang II type 1 (AT₁) and type 2 (AT₂) receptors, AT₁ and AT₂ receptors have antagonistic actions with regard to cell signaling. The molecular mechanisms that underlie this antagonism are not well understood. We examined AT₁ and AT₂ receptor-induced signal cross-talk in the cytoplasm and the importance of the hetero-dimerization of AT₁ receptor with AT₂ receptor on the cell surface. AT₁ and AT₂ receptors showed antagonistic effects toward inositol phosphate production. AT₁ receptors mainly formed homo-dimers, rather than hetero-dimers with AT₂ receptor, on the cell surface as determined by immunoprecipitation, and subsequently induced cell signals. AT₂ receptor mainly formed homo-dimers, rather than hetero-dimers with AT₁ receptor, on the cell surface. The expression levels of homo-dimerized AT₁ receptor or AT₂ receptor on the cell surface did not change after treatment with Ang II, the AT₁ receptor antagonist telmisartan or the AT₂ receptor antagonist PD123319. Finally, AT₁ and AT₂ receptor-induced signals antagonized phospholipase C-β₃ phosphorylation. In conclusion, Ang II-induced AT₁ receptor signals may be mainly blocked by AT₂ receptor signals through their negative cross-talk in the cytoplasm rather than by the hetero-dimerization of both receptors on the cell surface. The proper balance of the expression levels of AT₁ and AT₂ receptors might be critical for the antagonistic action between these receptors.     

Model of the whole rat AT1 receptor and the ligand-binding site

We present a three-dimensional model of the rat type 1 receptor (AT₁) for the hormone angiotensin II (Ang II). Ang II and the AT₁ receptor play a critical role in the cell-signaling process responsible for the actions of renin–angiotensin system in the regulation of blood pressure, water-electrolyte homeostasis and cell growth. Development of improved therapeutics would be significantly enhanced with the availability of a 3D-structure model for the AT₁ receptor and of the binding site for agonists and antagonists. This model was constructed using a combination of computation and homology-modeling techniques starting with the experimentally determined three-dimensional structure of bovine rhodopsin (PDB#1F88) as a template. All 359 residues and two disulfide bonds in the rat AT₁ receptor have been accounted for in this model. Ramachandran-map analysis and a 1 nanosecond molecular dynamics simulation of the solvated receptor with and without the bound ligand, Ang II, lend credence to the validity of the model. Docking calculations were performed with the agonist, Ang II and the antihypertensive antagonist, losartan.      

Involvement of the AT1 receptor in the venoconstriction induced by angiotensin II in both the inferior vena cava and femoral vein

Although angiotensin II-induced venoconstriction has been demonstrated in the rat vena cava and femoral vein, the angiotensin II receptor subtypes (AT₁ or AT₂) that mediate this phenomenon have not been precisely characterized. Therefore, the present study aimed to characterize the pharmacological receptors involved in the angiotensin II-induced constriction of rat venae cavae and femoral veins, as well as the opposing effects exerted by locally produced prostanoids and NO upon induction of these vasomotor responses. The obtained results suggest that both AT₁ and AT₂ angiotensin II receptors are expressed in both veins. Angiotensin II concentration-response curves were shifted toward the right by losartan but not by PD 123319 in both the vena cava and femoral vein. Moreover, it was observed that both 10⁻⁵ M indomethacin and 10⁻⁴ M L-NAME improve the angiotensin II responses in the vena cava and femoral vein. In conclusion, in the rat vena cava and femoral vein, angiotensin II stimulates AT₁ but not AT₂ to induce venoconstriction, which is blunted by vasodilator prostanoids and NO.     

A bioluminescence resonance energy transfer 2 (BRET2) assay for monitoring seven transmembrane receptor and insulin receptor crosstalk

The angiotensin AT₁ receptor is a seven transmembrane (7TM) receptor, which mediates the regulation of blood pressure. Activation of angiotensin AT₁ receptor may lead to impaired insulin signaling indicating crosstalk between angiotensin AT₁ receptor and insulin receptor signaling pathways. To elucidate the molecular mechanisms behind this crosstalk, we applied the BRET² technique to monitor the effect of angiotensin II on the interaction between Rluc⁸ tagged insulin receptor and GFP² tagged insulin receptor substrates 1, 4, 5 (IRS1, IRS4, IRS5) and Src homology 2 domain-containing protein (Shc). We demonstrate that angiotensin II reduces the interaction between insulin receptor and IRS1 and IRS4, respectively, while the interaction with Shc is unaffected, and this effect is dependent on Gαq activation. Activation of other Gαq-coupled 7TM receptors led to a similar reduction in insulin receptor and IRS4 interactions whereas Gαs- and Gαi-coupled 7TM receptors had no effect. Furthermore, we used a panel of kinase inhibitors to show that angiotensin II engages different pathways when regulating insulin receptor interactions with IRS1 and IRS4. Angiotensin II inhibited the interaction between insulin receptor and IRS1 through activation of ERK1/2, while the interaction between insulin receptor and IRS4 was partially inhibited through protein kinase C dependent mechanisms. We conclude that the crosstalk between angiotensin AT₁ receptor and insulin receptor signaling shows a high degree of specificity, and involves Gαq protein, and activation of distinct kinases. Thus, the BRET² technique can be used as a platform for studying molecular mechanisms of crosstalk between insulin receptor and 7TM receptors.     

Heteromerization of angiotensin receptors changes trafficking and arrestin recruitment profiles

The cardiovascular hormone angiotensin II (AngII) exerts its actions via two G protein-coupled receptor (GPCR) subtypes, AT₁ and AT₂, which often display antagonistic functions. Methodological constraints have so far precluded detailed analyses of the ligand-dependency, cellular localization, and functional relevance of AngII receptor interactions in live cells. In this study, we utilize a protein-fragment complementation assay (PCA) and GPCR-Heteromer Identification Technology (GPCR-HIT) to provide the first detailed investigation of the ligand-dependency and cellular localization of AngII receptor interactions in human embryonic kidney 293 cells. Fluorescent-tagged receptor constructs for PCA and GPCR-HIT displayed normal affinity and selectivity for AngII (AT₁: IC₅₀ = 1.0-1.6 nM; AT₂: IC₅₀ = 2.0-3.0 nM). Well-characterized angiotensin receptor interactions were used as positive and negative controls to demonstrate the sensitivity and specificity of these fluorescence-based assays. We report that AT₁-AT₂ receptor heteromers form constitutively, are localized to the plasma membrane and perinuclear compartments, and do not internalize following AngII stimulation despite arrestin being recruited specifically to the heteromer. Our findings using novel fluorescence-based technologies reveal a previously unrecognized mechanism of angiotensin receptor cross-talk involving cross-inhibition of AT₁ receptor internalization through heteromerization with the AT₂ receptor subtype.     

Reduction of infarct size by orally administered des-aspartate-angiotensin I in the ischemic reperfused rat heart

Occlusion of the left main coronary artery for 45 min caused sizable infarct scaring of the left ventricular wall in the rat heart at 14 days post-reperfusion. Daily oral administration of des-aspartate-angiotensin I (DAA-I) for 14 days attenuated the area of the infarct scar and transmurality. The attenuation was dose-dependent and biphasic; maximum effective dose was 1524 nmol/kg, and doses higher than this were progressively inactive. The exact mechanism of the biphasic attenuation is not known, and receptor down-regulation by internalization, which has been implicated in a similar biphasic nature for the anticardiac hypertrophic action of DAA-I, could be a likely cause. Indomethacin (101 μmol/kg, i.p.), administered sequentially after the daily oral dose of DAA-I (1524 nmol/kg), completely inhibited the attenuation at 14 days post-reperfusion, indicating that prostaglandins may be involved in transducing the attenuation. The present findings support earlier indications that DAA-I exerts protective actions in cardiovascular pathologies in which angiotensin II is implicated. It is suggested that DAA-I exerts the cardioprotective action by acting on the same indomethacin-sensitive angiotensin AT₁ receptor. Although similar array of protective actions are also seen with another endogenous angiotensin, angiotensin-(1–7), the present findings demonstrate for the first time the ability of an endogenous angiotensin to reduce the infarct size of an ischemic-reperfusion injured rat heart.     

Postnatal Ontogeny of Angiotensin Receptors and ACE2 in Male and Female Rats

BackgroundSex differences in the expression of the angiotensin (Ang) II receptors and angiotensin-converting enzyme 2 (ACE2) have been hypothesized to be a potential mechanism contributing to sex-specific differences in arterial pressure. Currently, sex differences in the expression of the angiotensin receptors and ACE2 remain undefined.ObjectivesThe aim of this study was to define the postnatal ontogeny of mRNA expression, from birth to adulthood, of the Ang II and Ang-(1-7) receptors and ACE2 in male and female rats.MethodsKidney and heart tissue was collected from male and female Sprague Dawley rats and snap-frozen at postnatal days (PNDs) 1, 30, 42, 70, and 110 (adult), and real-time polymerase chain reaction was performed to determine relative expression of the Ang II and Ang-(1-7) receptors (AT_1aR, AT_1bR, AT₂R, and MasR) and ACE2.ResultsAll these components of the renin-angiotensin system (RAS) were detected in the kidney and left ventricle, although expression levels differed significantly between the sexes and across organs. Gene expression of most components of the RAS was high at birth and decreased with age in both sexes, except for ACE2 expression, which increased in the left ventricle with age (P_Age < 0.001). Low levels of AT₂R were observed in the ventricles in both sexes as adults. Most notably, AT₂R expression was greatest in female kidneys and lowest in male kidneys compared with the left ventricle (P_Age*Sex < 0.05). Interestingly, MasR expression in the female kidney was similar to the level of AT₂R expression. Left ventricular MasR expression was greater than AT₂R expression in both sexes but was not different between the sexes. The highest level of ACE2 expression was observed in adult female kidneys (P_AS < 0.05).ConclusionsThe enhanced mRNA expression of the vasodilatory arm of the renal RAS (ACE2, AT₂R) in females observed in the present study may contribute to sex differences in the regulation of arterial pressure and the incidence of cardiovascular disease in women.     

Commercially Available Angiotensin II At2 Receptor Antibodies Are Nonspecific

Commercially available angiotensin II AT₂ receptor antibodies are widely employed for receptor localization and quantification, but they have not been adequately validated. In this study, we characterized three commercially available AT₂ receptor antibodies: 2818-1 from Epitomics, sc-9040 from Santa Cruz Biotechnology, Inc., and AAR-012 from Alomone Labs. Using western blot analysis the immunostaining patterns observed were different for every antibody tested, and in most cases consisted of multiple immunoreactive bands. Identical immunoreactive patterns were present in wild-type and AT₂ receptor knockout mice not expressing the target protein. In the mouse brain, immunocytochemical studies revealed very different cellular immunoreactivity for each antibody tested. While the 2818-1 antibody reacted only with endothelial cells in small parenchymal arteries, the sc-9040 antibody reacted only with ependymal cells lining the cerebral ventricles, and the AAR-012 antibody reacted only with multiple neuronal cell bodies in the cerebral cortex. Moreover, the immunoreactivities were identical in brain tissue from wild-type or AT₂ receptor knockout mice. Furthermore, in both mice and rat tissue extracts, there was no correlation between the observed immunoreactivity and the presence or absence of AT₂ receptor binding or gene expression. We conclude that none of these commercially available AT₂ receptor antibodies tested met the criteria for specificity. In the absence of full antibody characterization, competitive radioligand binding and determination of mRNA expression remain the only reliable approaches to study AT₂ receptor expression.     

The potential therapeutic use of renin–angiotensin system inhibitors in the treatment of inflammatory diseases

Inflammation is a normal part of the immune response to injury or infection but its dysregulation promotes the development of inflammatory diseases, which cause considerable human suffering. Nonsteroidal anti-inflammatory agents are the most commonly prescribed agents for the treatment of inflammatory diseases, but they are accompanied by a broad range of side effects, including gastrointestinal and cardiovascular events. The renin–angiotensin system (RAS) is traditionally known for its role in blood pressure regulation. However, there is increasing evidence that RAS signaling is also involved in the inflammatory response associated with several disease states. Angiotensin II increases blood pressure by binding to angiotensin type 1 (AT₁) receptor, and direct renin inhibitors, angiotensin-converting enzyme (ACE) inhibitors and AT₁ receptor blockers (ARBs) are clinically used as antihypertensive agents. Recent data suggest that these drugs also have anti-inflammatory effects. Therefore, this review summarizes these recent findings for the efficacy of two of the most widely used antihypertensive drug classes, ACE inhibitors and ARBs, to reduce or treat inflammatory diseases such as atherosclerosis, arthritis, steatohepatitis, colitis, pancreatitis, and nephritis.