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19 pages, 47429 KiB  
Article
Overexpression of (P)RR in SHR and Renin-Induced HepG2 Cells Leads to Spontaneous Hypertension Combined with Metabolic Dysfunction-Associated Fatty Liver Disease
by Chen Gao, Xinyi Guo, Lingzhi Zhang, Xueman Lin and Hua Sun
Int. J. Mol. Sci. 2025, 26(13), 6541; https://doi.org/10.3390/ijms26136541 - 7 Jul 2025
Viewed by 525
Abstract
Hypertension and metabolic dysfunction-associated fatty liver disease (MAFLD) are both common chronic diseases globally. Nearly half of patients with hypertension are complicated by MAFLD. The mechanisms of the bidirectional promotion between the two remain unclear. The (pro) renin receptor ((P)RR) is one of [...] Read more.
Hypertension and metabolic dysfunction-associated fatty liver disease (MAFLD) are both common chronic diseases globally. Nearly half of patients with hypertension are complicated by MAFLD. The mechanisms of the bidirectional promotion between the two remain unclear. The (pro) renin receptor ((P)RR) is one of the classic members of the renin–angiotensin system (RAS) and serves as the receptor for prorenin. Although the role of (P)RR in the induction and progression of hypertension has been extensively studied, its role and underlying mechanisms in MAFLD remain underreported. In this study, we aim to investigate the role of (P)RR in the pathogenesis of hypertension combined with MAFLD. In this study, SHRs were used for the model for hypertension combined with MAFLD. Liver lipid content analysis, liver H&E staining, the detection of (P)RR, ERK and downstream proteins related to fatty acid synthesis and transport, and RNA sequencing and data analysis were performed. In the in vitro experiments, we activated (P)RR using renin and established the lipid deposition model of HepG2 cells induced by renin for the first time. (P)RR was specifically blocked using handle region peptide (HRP), and Nile red fluorescence staining, (P)RR/ERK/PPARγ protein expression analysis, and immunofluorescence were performed to further verify the role of (P)RR in the pathogenesis of hypertension combined with MAFLD. Our results demonstrate that (P)RR plays a role in the development and progression of hypertension combined with MAFLD. The hepatic TG and FFA levels in the SHRs were increased, and the protein expression of the (P)RR/ERK/PPARγ pathway and downstream proteins related to fatty acid synthesis and transport were upregulated. HRP reversed the activation of these proteins and reduced intracellular lipid accumulation. In conclusion, our study first reveals that (P)RR is a potential therapeutic target for hypertension combined with MAFLD. And we found the (P)RR/ERK/PPARγ axis for the first time, which plays an important role in the progression of spontaneous hypertension combined with MAFLD. Full article
(This article belongs to the Section Molecular Pathology, Diagnostics, and Therapeutics)
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27 pages, 3323 KiB  
Article
Inhibition of the Renin–Angiotensin System Improves Hemodynamic Function of the Diabetic Rat Heart by Restoring Intracellular Calcium Regulation
by Krisztina Anna Paulik, Tamás Ivanics, Gábor A. Dunay, Ágnes Fülöp, Margit Kerék, Klára Takács, Zoltán Benyó and Zsuzsanna Miklós
Biomedicines 2025, 13(3), 757; https://doi.org/10.3390/biomedicines13030757 - 20 Mar 2025
Cited by 1 | Viewed by 709
Abstract
Background/Objectives: Disrupted intracellular calcium (Ca2+i) regulation and renin–angiotensin system (RAS) activation are pathogenetic factors in diabetic cardiomyopathy, a major complication of type 1 (T1D) and type 2 (T2D) diabetes. This study explored their potential link in diabetic rat hearts. Methods: [...] Read more.
Background/Objectives: Disrupted intracellular calcium (Ca2+i) regulation and renin–angiotensin system (RAS) activation are pathogenetic factors in diabetic cardiomyopathy, a major complication of type 1 (T1D) and type 2 (T2D) diabetes. This study explored their potential link in diabetic rat hearts. Methods: Experiments were conducted on T1D and T2D Sprague-Dawley rats induced by streptozotocin and fructose-rich diet, respectively. In T1D, rats were treated with Enalapril (Ena) or Losartan (Los) for six weeks, whereas T2D animals received high-dose (HD) or low-dose (LD) Ena for 8 weeks. Heart function was assessed via echocardiography, Ca2+i transients by Indo-1 fluorometry in Langendorff-perfused hearts, and key Ca2+i cycling proteins by Western blot. Data: mean ± SD. Results: Diabetic hearts exhibited reduced contractile performance that was improved by RAS inhibition both in vivo (ejection fraction (%): T1D model: Control: 79 ± 7, T1D: 54 ± 11, T1D + Ena: 65 ± 10, T1D + Los: 69 ± 10, n = 18, 18, 15, 10; T2D model: Control: 73 ± 8, T2D: 52 ± 6, T2D + LDEna: 62 ± 8, T2D + HDEna: 76 ± 8, n = 9, 8, 6, 7) and ex vivo (+dPressure/dtmax (mmHg/s): T1D model: Control: 2532 ± 341, T1D: 2192 ± 208, T1D + Ena: 2523 ± 485, T1D + Los: 2643 ± 455; T2D model: Control: 2514 ± 197, T2D: 1930 ± 291, T2D + LDEna: 2311 ± 289, T2D + HDEna: 2614 ± 268). Analysis of Ca2+i transients showed impaired Ca2+i release and removal dynamics and increased diastolic Ca2+i levels in both models that were restored by Ena and Los treatments. We observed a decrease in sarcoendoplasmic reticulum Ca2+-ATPase2a (SERCA2a) expression, accompanied by a compensatory increase in 16Ser-phosphorylated phospholamban (P-PLB) in T2D that was prevented by both LD and HD Ena (expression level (% of Control): SERCA2a: T2D: 36 ± 32, T2D + LDEna: 112 ± 32, T2D + HDEna: 106 ± 30; P-PLB: T2D: 557 ± 156, T2D + LDEna: 129 ± 38, T2D + HDEna: 108 ± 42; n = 4, 4, 4). Conclusions: The study highlights the critical role of RAS activation, most likely occurring at the tissue level, in disrupting Ca2+i homeostasis in diabetic cardiomyopathy. RAS inhibition with Ena or Los mitigates these disturbances independent of blood pressure effects, underlining their importance in managing diabetic heart failure. Full article
(This article belongs to the Special Issue Renin-Angiotensin System in Cardiovascular Biology, 2nd Edition)
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18 pages, 4300 KiB  
Article
Angiotensin II Induces Vascular Endothelial Dysfunction by Promoting Lipid Peroxidation-Mediated Ferroptosis via CD36
by Qian Zhou, Ying Zhang, Wei Shi, Lu Lu, Jianglan Wei, Jinhan Wang, Hu Zhang, Yuepu Pu and Lihong Yin
Biomolecules 2024, 14(11), 1456; https://doi.org/10.3390/biom14111456 - 17 Nov 2024
Cited by 4 | Viewed by 2368
Abstract
Angiotensin II (Ang II) is an effective vasoconstriction peptide, a major effector molecule of the renin–angiotensin–aldosterone system (RAAS) and one of the important causes of endothelial dysfunction. Ferroptosis is considered to be involved in the occurrence and development of cardiovascular diseases. This study [...] Read more.
Angiotensin II (Ang II) is an effective vasoconstriction peptide, a major effector molecule of the renin–angiotensin–aldosterone system (RAAS) and one of the important causes of endothelial dysfunction. Ferroptosis is considered to be involved in the occurrence and development of cardiovascular diseases. This study is dedicated to exploring the role and mechanism of Ang II-induced ferroptosis in HUVECs and to finding molecular targets for vascular endothelial injury and dysfunction during the progression of hypertension. In this study, we found that with the increase in exposure concentration, the intracellular ROS content and apoptosis rate increased significantly, the NO release decreased significantly in the medium- and high-concentration groups and the ET-1 content in the high-concentration group increased significantly. The expression of ZO-1 protein was significantly decreased in the high-concentration group. The expression of p-eNOS, VE-cadherin and Occludin protein showed a dose-dependent downward trend, while the ICAM-1 protein showed an upward trend. Ang II caused lipid metabolism disorders in HUVECs, and the PL–PUFAs associated with ferroptosis were significantly increased. In addition, Ang II promoted a significant increase in intracellular free Fe2+ content and MDA and a significant decrease in GSH content. Furthermore, the expression of GPX4, SLC7A11 and SLC3A2 was down-regulated, the expression of ACSL4, LPCAT3 and ALOX15 was up-regulated, and the ratio of p-cPLA2/cPLA2 was increased. After the intervention of ferroptosis inhibitor Fer-1, the injury and dysfunction of HUVECs induced by Ang II were significantly rescued. Immunofluorescence results showed that the expression of CD36 showed a significant increasing trend and was localized in the cytoplasm. Over-expression of CD36 promoted Ang II-induced ferroptosis and endothelial dysfunction. In conclusion, Ang II induces the injury of HUVECs, decreases vascular diastole and endothelial barrier-related molecules, and increases vascular constriction and adhesion-related molecules, which may be related to CD36 and its mediated lipid peroxidation and ferroptosis signals. Full article
(This article belongs to the Section Molecular Biology)
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18 pages, 2089 KiB  
Review
Untangling the Uncertain Role of Overactivation of the Renin–Angiotensin–Aldosterone System with the Aging Process Based on Sodium Wasting Human Models
by Chantelle Thimm and James Adjaye
Int. J. Mol. Sci. 2024, 25(17), 9332; https://doi.org/10.3390/ijms25179332 - 28 Aug 2024
Cited by 3 | Viewed by 2635
Abstract
Every individual at some point encounters the progressive biological process of aging, which is considered one of the major risk factors for common diseases. The main drivers of aging are oxidative stress, senescence, and reactive oxygen species (ROS). The renin–angiotensin–aldosterone system (RAAS) includes [...] Read more.
Every individual at some point encounters the progressive biological process of aging, which is considered one of the major risk factors for common diseases. The main drivers of aging are oxidative stress, senescence, and reactive oxygen species (ROS). The renin–angiotensin–aldosterone system (RAAS) includes several systematic processes for the regulation of blood pressure, which is caused by an imbalance of electrolytes. During activation of the RAAS, binding of angiotensin II (ANG II) to angiotensin II type 1 receptor (AGTR1) activates intracellular nicotinamide adenine dinucleotide phosphate (NADPH) oxidase to generate superoxide anions and promote uncoupling of endothelial nitric oxide (NO) synthase, which in turn decreases NO availability and increases ROS production. Promoting oxidative stress and DNA damage mediated by ANG II is tightly regulated. Individuals with sodium deficiency-associated diseases such as Gitelman syndrome (GS) and Bartter syndrome (BS) show downregulation of inflammation-related processes and have reduced oxidative stress and ROS. Additionally, the histone deacetylase sirtuin-1 (SIRT1) has a significant impact on the aging process, with reduced activity with age. However, GS/BS patients generally sustain higher levels of sirtuin-1 (SIRT1) activity than age-matched healthy individuals. SIRT1 expression in GS/BS patients tends to be higher than in healthy age-matched individuals; therefore, it can be assumed that there will be a trend towards healthy aging in these patients. In this review, we highlight the importance of the hallmarks of aging, inflammation, and the RAAS system in GS/BS patients and how this might impact healthy aging. We further propose future research directions for studying the etiology of GS/BS at the molecular level using patient-derived renal stem cells and induced pluripotent stem cells. Full article
(This article belongs to the Section Molecular Immunology)
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15 pages, 2123 KiB  
Article
Sodium–Glucose Cotransporter 2 Inhibitor Combined with Conventional Diuretics Ameliorate Body Fluid Retention without Excessive Plasma Volume Reduction
by Maki Asakura-Kinoshita, Takahiro Masuda, Kentaro Oka, Ken Ohara, Marina Miura, Masato Morinari, Kyohei Misawa, Yasuharu Miyazawa, Tetsu Akimoto, Kazuyuki Shimada and Daisuke Nagata
Diagnostics 2024, 14(11), 1194; https://doi.org/10.3390/diagnostics14111194 - 5 Jun 2024
Cited by 4 | Viewed by 3391
Abstract
We previously reported that sodium–glucose cotransporter 2 (SGLT2) inhibitors exert sustained fluid homeostatic actions through compensatory increases in osmotic diuresis-induced vasopressin secretion and fluid intake. However, SGLT2 inhibitors alone do not produce durable amelioration of fluid retention. In this study, we examined the [...] Read more.
We previously reported that sodium–glucose cotransporter 2 (SGLT2) inhibitors exert sustained fluid homeostatic actions through compensatory increases in osmotic diuresis-induced vasopressin secretion and fluid intake. However, SGLT2 inhibitors alone do not produce durable amelioration of fluid retention. In this study, we examined the comparative effects of the SGLT2 inhibitor dapagliflozin (SGLT2i group, n = 53) and the combined use of dapagliflozin and conventional diuretics, including loop diuretics and/or thiazides (SGLT2i + diuretic group, n = 23), on serum copeptin, a stable, sensitive, and simple surrogate marker of vasopressin release and body fluid status. After six months of treatment, the change in copeptin was significantly lower in the SGLT2i + diuretic group than in the SGLT2i group (−1.4 ± 31.5% vs. 31.5 ± 56.3%, p = 0.0153). The change in the estimated plasma volume calculated using the Strauss formula was not significantly different between the two groups. Contrastingly, changes in interstitial fluid, extracellular water, intracellular water, and total body water were significantly lower in the SGLT2i + diuretic group than in the SGLT2i group. Changes in renin, aldosterone, and absolute epinephrine levels were not significantly different between the two groups. In conclusion, the combined use of the SGLT2 inhibitor dapagliflozin and conventional diuretics inhibited the increase in copeptin levels and remarkably ameliorated fluid retention without excessively reducing plasma volume and activating the renin–angiotensin–aldosterone and sympathetic nervous systems. Full article
(This article belongs to the Special Issue Kidney Disease: Biomarkers, Diagnosis, and Prognosis: 3rd Edition)
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15 pages, 3191 KiB  
Article
Renal Expression and Localization of the Receptor for (Pro)renin and Its Ligands in Rodent Models of Diabetes, Metabolic Syndrome, and Age-Dependent Focal and Segmental Glomerulosclerosis
by Carla Iacobini, Martina Vitale, Federica Sentinelli, Jonida Haxhi, Giuseppe Pugliese and Stefano Menini
Int. J. Mol. Sci. 2024, 25(4), 2217; https://doi.org/10.3390/ijms25042217 - 12 Feb 2024
Cited by 2 | Viewed by 1597
Abstract
The (pro)renin receptor ((P)RR), a versatile protein found in various organs, including the kidney, is implicated in cardiometabolic conditions like diabetes, hypertension, and dyslipidemia, potentially contributing to organ damage. Importantly, changes in (pro)renin/(P)RR system localization during renal injury, a critical information base, remain [...] Read more.
The (pro)renin receptor ((P)RR), a versatile protein found in various organs, including the kidney, is implicated in cardiometabolic conditions like diabetes, hypertension, and dyslipidemia, potentially contributing to organ damage. Importantly, changes in (pro)renin/(P)RR system localization during renal injury, a critical information base, remain unexplored. This study investigates the expression and topographic localization of the full length (FL)-(P)RR, its ligands (renin and prorenin), and its target cyclooxygenase-2 and found that they are upregulated in three distinct animal models of renal injury. The protein expression of these targets, initially confined to specific tubular renal cell types in control animals, increases in renal injury models, extending to glomerular cells. (P)RR gene expression correlates with protein changes in a genetic model of focal and segmental glomerulosclerosis. However, in diabetic and high-fat-fed mice, (P)RR mRNA levels contradict FL-(P)RR immunoreactivity. Research on diabetic mice kidneys and human podocytes exposed to diabetic glucose levels suggests that this inconsistency may result from disrupted intracellular (P)RR processing, likely due to increased Munc18-1 interacting protein 3. It follows that changes in FL-(P)RR cellular content mechanisms are specific to renal disease etiology, emphasizing the need for consideration in future studies exploring this receptor’s involvement in renal damage of different origins. Full article
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13 pages, 1125 KiB  
Review
Primary Role of the Kidney in Pathogenesis of Hypertension
by Gheun-Ho Kim
Life 2024, 14(1), 119; https://doi.org/10.3390/life14010119 - 14 Jan 2024
Cited by 8 | Viewed by 10025
Abstract
Previous transplantation studies and the concept of ‘nephron underdosing’ support the idea that the kidney plays a crucial role in the development of essential hypertension. This suggests that there are genetic factors in the kidney that can either elevate or decrease blood pressure. [...] Read more.
Previous transplantation studies and the concept of ‘nephron underdosing’ support the idea that the kidney plays a crucial role in the development of essential hypertension. This suggests that there are genetic factors in the kidney that can either elevate or decrease blood pressure. The kidney normally maintains arterial pressure within a narrow range by employing the mechanism of pressure-natriuresis. Hypertension is induced when the pressure-natriuresis mechanism fails due to both subtle and overt kidney abnormalities. The inheritance of hypertension is believed to be polygenic, and essential hypertension may result from a combination of genetic variants that code for renal tubular sodium transporters or proteins involved in regulatory pathways. The renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system (SNS) are the major regulators of renal sodium reabsorption. Hyperactivity of either the RAAS or SNS leads to a rightward shift in the pressure-natriuresis curve. In other words, hypertension is induced when the activity of RAAS and SNS is not suppressed despite increased salt intake. Sodium overload, caused by increased intake and/or reduced renal excretion, not only leads to an expansion of plasma volume but also to an increase in systemic vascular resistance. Endothelial dysfunction is caused by an increased intracellular Na+ concentration, which inhibits endothelial nitric oxide (NO) synthase and reduces NO production. The stiffness of vascular smooth muscle cells is increased by the accumulation of intracellular Na+ and subsequent elevation of cytoplasmic Ca++ concentration. In contrast to the hemodynamic effects of osmotically active Na+, osmotically inactive Na+ stimulates immune cells and produces proinflammatory cytokines, which contribute to hypertension. When this occurs in the gut, the microbiota may become imbalanced, leading to intestinal inflammation and systemic hypertension. In conclusion, the primary cause of hypertension is sodium overload resulting from kidney dysregulation. Full article
(This article belongs to the Special Issue Pulmonary Hypertension: From Bench to Bedside: 2nd Edition)
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25 pages, 1312 KiB  
Review
Reactive Oxygen Species Are Central Mediators of Vascular Dysfunction and Hypertension Induced by Ethanol Consumption
by Júlio C. Padovan, Thales M. H. Dourado, Gustavo F. Pimenta, Thiago Bruder-Nascimento and Carlos R. Tirapelli
Antioxidants 2023, 12(10), 1813; https://doi.org/10.3390/antiox12101813 - 29 Sep 2023
Cited by 11 | Viewed by 3004
Abstract
Consumption of high amounts of ethanol is a risk factor for development of cardiovascular diseases such as arterial hypertension. The hypertensive state induced by ethanol is a complex multi-factorial event, and oxidative stress is a pathophysiological hallmark of vascular dysfunction associated with ethanol [...] Read more.
Consumption of high amounts of ethanol is a risk factor for development of cardiovascular diseases such as arterial hypertension. The hypertensive state induced by ethanol is a complex multi-factorial event, and oxidative stress is a pathophysiological hallmark of vascular dysfunction associated with ethanol consumption. Increasing levels of reactive oxygen species (ROS) in the vasculature trigger important processes underlying vascular injury, including accumulation of intracellular Ca2+ ions, reduced bioavailability of nitric oxide (NO), activation of mitogen-activated protein kinases (MAPKs), endothelial dysfunction, and loss of the anticontractile effect of perivascular adipose tissue (PVAT). The enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase plays a central role in vascular ROS generation in response to ethanol. Activation of the renin–angiotensin–aldosterone system (RAAS) is an upstream mechanism which contributes to NADPH oxidase stimulation, overproduction of ROS, and vascular dysfunction. This review discusses the mechanisms of vascular dysfunction induced by ethanol, detailing the contribution of ROS to these processes. Data examining the association between neuroendocrine changes and vascular oxidative stress induced by ethanol are also reviewed and discussed. These issues are of paramount interest to public health as ethanol contributes to blood pressure elevation in the general population, and it is linked to cardiovascular conditions and diseases. Full article
(This article belongs to the Special Issue Oxidative Stress in Cardiorenal System)
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15 pages, 1360 KiB  
Review
Non-Haemodynamic Mechanisms Underlying Hypertension-Associated Damage in Target Kidney Components
by Elisa Russo, Elisabetta Bussalino, Lucia Macciò, Daniela Verzola, Michela Saio, Pasquale Esposito, Giovanna Leoncini, Roberto Pontremoli and Francesca Viazzi
Int. J. Mol. Sci. 2023, 24(11), 9422; https://doi.org/10.3390/ijms24119422 - 29 May 2023
Cited by 12 | Viewed by 3032
Abstract
Arterial hypertension (AH) is a global challenge that greatly impacts cardiovascular morbidity and mortality worldwide. AH is a major risk factor for the development and progression of kidney disease. Several antihypertensive treatment options are already available to counteract the progression of kidney disease. [...] Read more.
Arterial hypertension (AH) is a global challenge that greatly impacts cardiovascular morbidity and mortality worldwide. AH is a major risk factor for the development and progression of kidney disease. Several antihypertensive treatment options are already available to counteract the progression of kidney disease. Despite the implementation of the clinical use of renin–angiotensin aldosterone system (RAAS) inhibitors, gliflozins, endothelin receptor antagonists, and their combination, the kidney damage associated with AH is far from being resolved. Fortunately, recent studies on the molecular mechanisms of AH-induced kidney damage have identified novel potential therapeutic targets. Several pathophysiologic pathways have been shown to play a key role in AH-induced kidney damage, including inappropriate tissue activation of the RAAS and immunity system, leading to oxidative stress and inflammation. Moreover, the intracellular effects of increased uric acid and cell phenotype transition showed their link with changes in kidney structure in the early phase of AH. Emerging therapies targeting novel disease mechanisms could provide powerful approaches for hypertensive nephropathy management in the future. In this review, we would like to focus on the interactions of pathways linking the molecular consequences of AH to kidney damage, suggesting how old and new therapies could aim to protect the kidney. Full article
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19 pages, 8924 KiB  
Article
Intracellular Angiotensin II Stimulation of Sodium Transporter Expression in Proximal Tubule Cells via AT1 (AT1a) Receptor-Mediated, MAP Kinases ERK1/2- and NF-кB-Dependent Signaling Pathways
by Xiaochun Li and Jialong Zhuo
Cells 2023, 12(11), 1492; https://doi.org/10.3390/cells12111492 - 28 May 2023
Cited by 2 | Viewed by 3382
Abstract
The current prevailing paradigm in the renin-angiotensin system dictates that most, if not all, biological, physiological, and pathological responses to its most potent peptide, angiotensin II (Ang II), are mediated by extracellular Ang II activating its cell surface receptors. Whether intracellular (or intracrine) [...] Read more.
The current prevailing paradigm in the renin-angiotensin system dictates that most, if not all, biological, physiological, and pathological responses to its most potent peptide, angiotensin II (Ang II), are mediated by extracellular Ang II activating its cell surface receptors. Whether intracellular (or intracrine) Ang II and its receptors are involved remains incompletely understood. The present study tested the hypothesis that extracellular Ang II is taken up by the proximal tubules of the kidney by an AT1 (AT1a) receptor-dependent mechanism and that overexpression of an intracellular Ang II fusion protein (ECFP/Ang II) in mouse proximal tubule cells (mPTC) stimulates the expression of Na+/H+ exchanger 3 (NHE3), Na+/HCO3- cotransporter, and sodium and glucose cotransporter 2 (Sglt2) by AT1a/MAPK/ERK1/2/NF-kB signaling pathways. mPCT cells derived from male wild-type and type 1a Ang II receptor-deficient mice (Agtr1a-/-) were transfected with an intracellular enhanced cyan fluorescent protein-tagged Ang II fusion protein, ECFP/Ang II, and treated without or with AT1 receptor blocker losartan, AT2 receptor blocker PD123319, MEK1/MEK2 inhibitor U0126, NF-кB inhibitor RO 106-9920, or p38 MAP kinase inhibitor SB202196, respectively. In wild-type mPCT cells, the expression of ECFP/Ang II significantly increased NHE3, Na+/HCO3-, and Sglt2 expression (p < 0.01). These responses were accompanied by >3-fold increases in the expression of phospho-ERK1/2 and the p65 subunit of NF-кB (p < 0.01). Losartan, U0126, or RO 106-9920 all significantly attenuated ECFP/Ang II-induced NHE3 and Na+/HCO3- expression (p < 0.01). Deletion of AT1 (AT1a) receptors in mPCT cells attenuated ECFP/Ang II-induced NHE3 and Na+/HCO3- expression (p < 0.01). Interestingly, the AT2 receptor blocker PD123319 also attenuated ECFP/Ang II-induced NHE3 and Na+/HCO3- expression (p < 0.01). These results suggest that, similar to extracellular Ang II, intracellular Ang II may also play an important role in Ang II receptor-mediated proximal tubule NHE3, Na+/HCO3-, and Sglt2 expression by activation of AT1a/MAPK/ERK1/2/NF-kB signaling pathways. Full article
(This article belongs to the Section Cells of the Cardiovascular System)
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20 pages, 3418 KiB  
Review
Unraveling the Underlying Molecular Mechanism of ‘Silent Hypoxia’ in COVID-19 Patients Suggests a Central Role for Angiotensin II Modulation of the AT1R-Hypoxia-Inducible Factor Signaling Pathway
by Christian Albert Devaux and Jean-Christophe Lagier
J. Clin. Med. 2023, 12(6), 2445; https://doi.org/10.3390/jcm12062445 - 22 Mar 2023
Cited by 7 | Viewed by 4397
Abstract
A few days after being infected with SARS-CoV-2, a fraction of people remain asymptomatic but suffer from a decrease in arterial oxygen saturation in the absence of apparent dyspnea. In light of our clinical investigation on the modulation of molecules belonging to the [...] Read more.
A few days after being infected with SARS-CoV-2, a fraction of people remain asymptomatic but suffer from a decrease in arterial oxygen saturation in the absence of apparent dyspnea. In light of our clinical investigation on the modulation of molecules belonging to the renin angiotensin system (RAS) in COVID-19 patients, we propose a model that explains ‘silent hypoxia’. The RAS imbalance caused by SARS-CoV-2 results in an accumulation of angiotensin 2 (Ang II), which activates the angiotensin 2 type 1 receptor (AT1R) and triggers a harmful cascade of intracellular signals leading to the nuclear translocation of the hypoxia-inducible factor (HIF)-1α. HIF-1α transactivates many genes including the angiotensin-converting enzyme 1 (ACE1), while at the same time, ACE2 is downregulated. A growing number of cells is maintained in a hypoxic condition that is self-sustained by the presence of the virus and the ACE1/ACE2 ratio imbalance. This is associated with a progressive worsening of the patient’s biological parameters including decreased oxygen saturation, without further clinical manifestations. When too many cells activate the Ang II-AT1R-HIF-1α axis, there is a ‘hypoxic spillover’, which marks the tipping point between ‘silent’ and symptomatic hypoxia in the patient. Immediate ventilation is required to prevent the ‘hypoxic spillover’. Full article
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14 pages, 7176 KiB  
Article
Exogenous H2S Attenuates Hypertension by Regulating Renin Exocytosis under Hyperglycaemic and Hyperlipidaemic Conditions
by Ning Liu, Mingyu Li, Siyuan Liu, Jiaxin Kang, Lingxue Chen, Jiayi Huang, Yan Wang, He Chen and Weihua Zhang
Int. J. Mol. Sci. 2023, 24(2), 1690; https://doi.org/10.3390/ijms24021690 - 14 Jan 2023
Cited by 10 | Viewed by 2705 | Correction
Abstract
Obesity, along with type 2 diabetes mellitus (T2DM), is a major contributor to hypertension. The renin-angiotensin-aldosterone system is involved in the occurrence of diabetes and hypertension. However, the mechanism by which obesity is related to T2DM induced hypertension is unclear. In this study, [...] Read more.
Obesity, along with type 2 diabetes mellitus (T2DM), is a major contributor to hypertension. The renin-angiotensin-aldosterone system is involved in the occurrence of diabetes and hypertension. However, the mechanism by which obesity is related to T2DM induced hypertension is unclear. In this study, we observed that blood pressure and serum renin content were increased in patients with diabetes and hypertension. Hydrogen sulfide (H2S), as an endogenous bioactive molecule, has been shown to be a vasodilator. Db/db mice, characterized by obesity and T2DM, and juxtaglomerular (JG) cells, which line the afferent arterioles at the entrance of the glomeruli to produce renin, treated with glucose, palmitic acid (PA) and oleic acid (OA), were used as animal and cellular models. NaHS, the H2S donor, was administered to db/db mice through intraperitoneal injection. NaHS significantly alleviated blood pressure in db/db mice, decreased the renin content in the serum of db/db mice and reduced renin secretion from JG cells. NaHS modulated renin release via cAMP and soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), including synaptosome-associated protein 23 (SNAP23) and vesicle-associated membrane protein 2 (VAMP2), which mediate renin exocytosis. Furthermore, NaHS increased the levels of autophagy-related proteins and colocalization with EGFP-LC3 puncta with renin-containing granules and VAMP2 to consume excessive renin to maintain intracellular homeostasis. Therefore, exogenous H2S attenuates renin release and promotes renin-vesicular autophagy to relieve diabetes-induced hypertension. Full article
(This article belongs to the Section Molecular Endocrinology and Metabolism)
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12 pages, 1312 KiB  
Review
Cardioprotective Mechanisms against Reperfusion Injury in Acute Myocardial Infarction: Targeting Angiotensin II Receptors
by Gabriel Méndez-Valdés, Vicente Pérez-Carreño, Maria Chiara Bragato, Malthe Hundahl, Silvia Chichiarelli, Luciano Saso and Ramón Rodrigo
Biomedicines 2023, 11(1), 17; https://doi.org/10.3390/biomedicines11010017 - 22 Dec 2022
Cited by 8 | Viewed by 2918
Abstract
Ischemia/reperfusion injury is a process associated with cardiologic interventions, such as percutaneous coronary angioplasty after an acute myocardial infarction. Blood flow restoration causes a quick burst of reactive oxygen species (ROS), which generates multiple organelle damage, leading to the activation of cell death [...] Read more.
Ischemia/reperfusion injury is a process associated with cardiologic interventions, such as percutaneous coronary angioplasty after an acute myocardial infarction. Blood flow restoration causes a quick burst of reactive oxygen species (ROS), which generates multiple organelle damage, leading to the activation of cell death pathways. Therefore, the intervention contributes to a greater necrotic zone, thus increasing the risk of cardiovascular complications. A major cardiovascular ROS source in this setting is the activation of multiple NADPH oxidases, which could result via the occupancy of type 1 angiotensin II receptors (AT1R); hence, the renin angiotensin system (RAS) is associated with the generation of ROS during reperfusion. In addition, ROS can promote the expression of NF-κΒ, a proinflammatory transcription factor. Recent studies have described an intracellular RAS pathway that is associated with increased intramitochondrial ROS through the action of isoform NOX4 of NADPH oxidase, thereby contributing to mitochondrial dysfunction. On the other hand, the angiotensin II/ angiotensin type 2 receptor (Ang II/AT2R) axis exerts its effects by counter-modulating the action of AT1R, by activating endothelial nitric oxide synthase (eNOS) and stimulating cardioprotective pathways such as akt. The aim of this review is to discuss the possible use of AT1R blockers to hamper both the Ang II/AT1R axis and the associated ROS burst. Moreover; we suggest that AT1R antagonist drugs should act synergistically with other cardioprotective agents, such as ascorbic acid, N-acetylcysteine and deferoxamine, leading to an enhanced reduction in the reperfusion injury. This therapy is currently being tested in our laboratory and has shown promising outcomes in experimental studies. Full article
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23 pages, 4334 KiB  
Article
In Vitro Characterization of a Tissue Renin-Angiotensin System in Human Nucleus Pulposus Cells
by Babak Saravi, Zhen Li, Valentina Basoli, Sibylle Grad, Sonja Häckel, Christoph E. Albers, Mauro Alini, Hagen Schmal, Peter Obid and Gernot Lang
Cells 2022, 11(21), 3418; https://doi.org/10.3390/cells11213418 - 28 Oct 2022
Cited by 1 | Viewed by 2520
Abstract
Low back pain is a clinically highly relevant musculoskeletal burden and is associated with inflammatory as well as degenerative processes of the intervertebral disc. However, the pathophysiology and cellular pathways contributing to this devastating condition are still poorly understood. Based on previous evidence, [...] Read more.
Low back pain is a clinically highly relevant musculoskeletal burden and is associated with inflammatory as well as degenerative processes of the intervertebral disc. However, the pathophysiology and cellular pathways contributing to this devastating condition are still poorly understood. Based on previous evidence, we hypothesize that tissue renin-angiotensin system (tRAS) components, including the SARS-CoV-2 entry receptor angiotensin-converting enzyme 2 (ACE2), are present in human nucleus pulposus (NP) cells and associated with inflammatory and degenerative processes. Experiments were performed with NP cells from four human donors. The existence of angiotensin II, angiotensin II type 1 receptor (AGTR1), AGTR2, MAS-receptor (MasR), and ACE2 in human NP cells was validated with immunofluorescent staining and gene expression analysis. Hereafter, the cell viability was assessed after adding agonists and antagonists of the target receptors as well as angiotensin II in different concentrations for up to 48 h of exposure. A TNF-α-induced inflammatory in vitro model was employed to assess the impact of angiotensin II addition and the stimulation or inhibition of the tRAS receptors on inflammation, tissue remodeling, expression of tRAS markers, and the release of nitric oxide (NO) into the medium. Furthermore, protein levels of IL-6, IL-8, IL-10, and intracellular as well as secreted angiotensin II were assessed after exposing the cells to the substances, and inducible nitric oxide synthase (iNOS) levels were evaluated by utilizing Western blot. The existence of tRAS receptors and angiotensin II were validated in human NP cells. The addition of angiotensin II only showed a mild impact on gene expression markers. However, there was a significant increase in NO secreted by the cells. The gene expression ratios of pro-inflammatory/anti-inflammatory cytokines IL-6/IL-10, IL-8/IL-10, and TNF-α/IL-10 were positively correlated with the AGTR1/AGTR2 and AGTR1/MAS1 ratios, respectively. The stimulation of the AGTR2 MAS-receptor and the inhibition of the AGTR1 receptor revealed beneficial effects on the gene expression of inflammatory and tissue remodeling markers. This finding was also present at the protein level. The current data showed that tRAS components are expressed in human NP cells and are associated with inflammatory and degenerative processes. Further characterization of the associated pathways is warranted. The findings indicate that tRAS modulation might be a novel therapeutic approach to intervertebral disc disease. Full article
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20 pages, 5134 KiB  
Article
Renin-a in the Subfornical Organ Plays a Critical Role in the Maintenance of Salt-Sensitive Hypertension
by Silvana G. Cooper, Lucas A. C. Souza, Caleb J. Worker, Ariana Julia B. Gayban, Sophie Buller, Ryosuke Satou and Yumei Feng Earley
Biomolecules 2022, 12(9), 1169; https://doi.org/10.3390/biom12091169 - 24 Aug 2022
Cited by 4 | Viewed by 2737
Abstract
The brain renin-angiotensin system plays important roles in blood pressure and cardiovascular regulation. There are two isoforms of prorenin in the brain: the classic secreted form (prorenin/sREN) encoded by renin-a, and an intracellular form (icREN) encoded by renin-b. Emerging evidence indicates the importance [...] Read more.
The brain renin-angiotensin system plays important roles in blood pressure and cardiovascular regulation. There are two isoforms of prorenin in the brain: the classic secreted form (prorenin/sREN) encoded by renin-a, and an intracellular form (icREN) encoded by renin-b. Emerging evidence indicates the importance of renin-b in cardiovascular and metabolic regulation. However, the role of endogenous brain prorenin in the development of salt-sensitive hypertension remains undefined. In this study, we test the hypothesis that renin-a produced locally in the brain contributes to the pathogenesis of hypertension. Using RNAscope, we report for the first time that renin mRNA is expressed in several regions of the brain, including the subfornical organ (SFO), the paraventricular nucleus of the hypothalamus (PVN), and the brainstem, where it is found in glutamatergic, GABAergic, cholinergic, and tyrosine hydroxylase-positive neurons. Notably, we found that renin mRNA was significantly elevated in the SFO and PVN in a mouse model of DOCA-salt–induced hypertension. To examine the functional importance of renin-a in the SFO, we selectively ablated renin-a in the SFO in renin-a–floxed mice using a Cre-lox strategy. Importantly, renin-a ablation in the SFO attenuated the maintenance of DOCA-salt–induced hypertension and improved autonomic function without affecting fluid or sodium intake. Molecularly, ablation of renin-a prevented the DOCA-salt–induced elevation in NADPH oxidase 2 (NOX2) in the SFO without affecting NOX4 or angiotensin II type 1 and 2 receptors. Collectively, our findings demonstrate that endogenous renin-a within the SFO is important for the pathogenesis of salt-sensitive hypertension. Full article
(This article belongs to the Special Issue Renin-Angiotensin System in Diseases)
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