Angiotensin Signaling Research Articles

Epigenetic upregulation of carotid body angiotensin signaling increases blood pressure.

Epigenetic changes can be shaped by a wide array of environmental cues as well as maternal health and behaviors. One of the most detrimental behaviors to the developing fetus is nicotine exposure. Perinatal nicotine exposure remains a significant risk factor for cardiovascular health and in particular, hypertension. Increased basal carotid body activity and excitation are significant contributors to hypertension. This study investigated the epigenetic changes to carotid body activity induced by perinatal nicotine exposure resulting in carotid body-mediated hypertension. Using a rodent model of perinatal nicotine exposure, we show that angiotensin II type 1 receptor is upregulated in the carotid bodies of nicotine-exposed offspring. These changes were attributed to an upregulation of genetic promotion as DNA methylation of angiotensin II type 1 receptor occurred within intron regions, exemplifying an upregulation of genetic transcription for these genes. Nicotine increased angiotensin signaling in vitro . Carotid body reactivity to angiotensin was increased in perinatal nicotine-exposed offspring compared to control offspring. Further, carotid body denervation reduced arterial pressure as a result of suppressed efferent sympathetic activity in perinatal nicotine-exposed offspring. Our data demonstrate that perinatal nicotine exposure adversely affects carotid body afferent sensing, which augments efferent sympathetic activity to increase vasoconstrictor signaling and induce hypertension. Targeting angiotensin signaling in the carotid bodies may provide a way to alleviate hypertension acquired by adverse maternal uterine environments in general and perinatal nicotine exposure in particular.

Epigenetic changes to the carotid body drive hypertension in perinatal nicotine exposed rats

Background: Epigenetic changes can be shaped by a wide array of environmental cues as well as maternal health and behaviors. One of the most detrimental behaviors to the developing fetus is nicotine exposure. Perinatal nicotine exposure remains as a significant risk factor for cardiovascular health and in particular, hypertension, as it has been shown to alter angiotensin signaling. Hypothesis: We hypothesized that perinatal nicotine exposure alters carotid body angiotensin signaling to induce hypertension in adult life. Methods: Pregnant Sprague-Dawley rats were exposed to nicotine (2mg/kg SQ, or PBS- control) from estrous day 6 to post-natal day (PND) 21. Experiments on pups took place from PND 56-90. Carotid bodies were harvested pooled together for RNAseq and confirmation of unbiased transcriptomics was conducted with qPCR. Blood pressure was measured with indwelling telemetry. ELISA assessed serum angiotensin. PC12 cells were used a surrogate for carotid body glomus cells and were used for calcium imaging. Results: Unbiased RNAseq of carotid bodies from nicotine exposed pups compared to saline control pups showed that KEGG pathways with significant angiotensin signaling components including Neuroactive ligand-receptor interaction (Log2FC=2.4, p=7.5x10−8) and Dopaminergic synapse (Log2FC=2.3, p=0.0007) were significantly upregulated. qPCR of carotid bodies demonstrated that Angiotensin II type 1 receptor (56%↑), Angiotensin II type 2 receptor (15%↑) and TRPV1 channels (63%↑) were upregulated in nicotine exposed pups compared to controls. Blood pressure measured in nicotine exposed pups was suppressed 1 day after bilateral carotid body denervation. Circulating angiotensin assessed from serum was similar between nicotine exposed and control pups. Calcium imaging of PC12 cells showed that nicotine significantly increased spike frequency in response to nicotine (0.2mg/ml). Incubation with nicotine + Angiotensin (50ng/ml) did not further increase spike frequency. This increased excitation was suppressed with losartan (3μM), AMG9810 (TRPV1 antagonist, 10μM) and combined blockade (p<0.05). Conclusion: Our data demonstrate that adverse maternal behaviors produce epigenetic changes to carotid bodies of offspring resulting in neurogenic hypertension. The epigenetic changes involve an Angiotensin-Angiotensin II type 1 receptor-TRPV1 channel axis in the carotid body without any significant systemic changes. We suggest carotid body modulation may have a significant health impact on offspring with adverse perinatal environmental exposures. UCOP TRDRP T32IP4707, T32KT4708. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Single and Combined Aluminium and Cadmium Exposure during Pregnancy Mediate Changes in Cardio Metabolic Indices in Mice

The potential risk of Aluminium and Cadmium co-exposure is high owing to evidence of their co-contamination of several food products. Therefore, the present study investigated effect of single and combined exposures of aluminium and cadmium during pregnancy on cardio metabolic changes in mice. Following delivery and at the end of 78 days postnatal development, it was observed that exposure to Al and Cd during pregnancy altered indices of cardiac function via pathways related to angiotensin, cardiac troponin and oxidative stress signalling which may have impacted directly on the histoarchitectural features of the heart. Comparatively, prenatal exposure to Cd alone impacted more negatively to the heart in relation to exposure to either Al only or co-exposure to Al and Cd.

Hypertension and urologic chronic pelvic pain syndrome: An analysis of MAPP-I data

BackgroundUrologic chronic pelvic pain syndrome (UCPPS), which includes interstitial cystitis/bladder pain syndrome (IC/BPS) and chronic prostatitis (CP/CPPS), is associated with increased voiding frequency, nocturia, and chronic pelvic pain. The cause of these diseases is unknown and likely involves many different mechanisms. Dysregulated renin-angiotensin-aldosterone-system (RAAS) signaling is a potential pathologic mechanism for IC/BPS and CP/CPPS. Many angiotensin receptor downstream signaling factors, including oxidative stress, fibrosis, mast cell recruitment, and increased inflammatory mediators, are present in the bladders of IC/BPS patients and prostates of CP/CPPS patients. Therefore, we aimed to test the hypothesis that UCPPS patients have dysregulated angiotensin signaling, resulting in increased hypertension compared to controls. Secondly, we evaluated symptom severity in patients with and without hypertension and antihypertensive medication use.MethodsData from UCPPS patients (n = 424), fibromyalgia or irritable bowel syndrome (positive controls, n = 200), and healthy controls (n = 415) were obtained from the NIDDK Multidisciplinary Approach to the Study of Chronic Pelvic Pain I (MAPP-I). Diagnosis of hypertension, current antihypertensive medications, pain severity, and urinary symptom severity were analyzed using chi-square test and t-test.ResultsThe combination of diagnosis and antihypertensive medications use was highest in the UCPPS group (n = 74, 18%), followed by positive (n = 34, 17%) and healthy controls (n = 48, 12%, p = 0.04). There were no differences in symptom severity based on hypertension in UCPPS and CP/CPPS; however, IC/BPS had worse ICSI (p = 0.031), AUA-SI (p = 0.04), and BPI pain severity (0.02). Patients (n = 7) with a hypertension diagnosis not on antihypertensive medications reported the greatest severity of pain and urinary symptoms.ConclusionThis pattern of findings suggests that there may be a relationship between hypertension and UCPPS. Treating hypertension among these patients may result in reduced pain and symptom severity. Further investigation on the relationship between hypertension, antihypertensive medication use, and UCPPS and the role of angiotensin signaling in UCPPS conditions is needed.

Meningeal interleukin-17-producing T cells mediate cognitive impairment in a mouse model of salt-sensitive hypertension.

Hypertension (HTN), a disease afflicting over one billion individuals worldwide, is a leading cause of cognitive impairment, the mechanisms of which remain poorly understood. In the present study, in a mouse model of HTN, we find that the neurovascular and cognitive dysfunction depends on interleukin (IL)-17, a cytokine elevated in individuals with HTN. However, neither circulating IL-17 nor brain angiotensin signaling can account for the dysfunction. Rather, IL-17 produced by T cells in the dura mater is the mediator released in the cerebrospinal fluid and activating IL-17 receptors on border-associated macrophages (BAMs). Accordingly, depleting BAMs, deleting IL-17 receptor A in brain macrophages or suppressing meningeal T cells rescues cognitive function without attenuating blood pressure elevation, circulating IL-17 or brain angiotensin signaling. Our data unveil a critical role of meningeal T cells and macrophage IL-17 signaling in the neurovascular and cognitive dysfunction in a mouse model of HTN.

Sodium appetite and thirst do not require angiotensinogen production in astrocytes or hepatocytes.

In addition to its renal and cardiovascular functions, angiotensin signaling is thought to be responsible for the increases in salt and water intake caused by hypovolemia. However, it remains unclear whether these behaviors require angiotensin production in the brain or liver. Here, we use in situ hybridization to identify tissue-specific expression of the genes required for producing angiotensin peptides, then use conditional genetic deletion of angiotensinogen (Agt) to test whether production in the brain or liver is necessary for sodium appetite and thirst. In the mouse brain, we identified expression of Agt (the precursor of all angiotensin peptides) in a large subset of astrocytes. We also identified Ren1 and Ace (enzymes required to produce angiotensin II) in the choroid plexus, and Ren1 in neurons within the nucleus ambiguus compact formation. In the liver, we confirmed that Agt is expressed in widespread hepatocytes. We next tested whether thirst and sodium appetite require angiotensinogen production in astrocytes or hepatocytes. Despite virtually eliminating expression in the brain, deleting astrocytic Agt did not reduce thirst or sodium appetite. Despite markedly reducing angiotensinogen in the blood, eliminating Agt from hepatocytes did not reduce thirst or sodium appetite, and in fact, these mice consumed the largest amounts of salt and water after sodium deprivation. Deleting Agt from both astrocytes and hepatocytes also did not prevent thirst or sodium appetite. Our findings suggest that angiotensin signaling is not required for sodium appetite or thirst and highlight the need to identify alternative signaling mechanisms. KEY POINTS: Angiotensin signaling is thought to be responsible for the increased thirst and sodium appetite caused by hypovolemia, producing elevated water and sodium intake. Specific cells in separate brain regions express the three genes needed to produce angiotensin peptides, but brain-specific deletion of the angiotensinogen gene (Agt), which encodes the lone precursor for all angiotensin peptides, did not reduce thirst or sodium appetite. Double-deletion of Agt from brain and liver also did not reduce thirst or sodium appetite. Liver-specific deletion of Agt reduced circulating angiotensinogen levels without reducing thirst or sodium appetite. Instead, these angiotensin-deficient mice exhibited an enhanced sodium appetite. Because the physiologic mechanisms controlling thirst and sodium appetite continued functioning without angiotensin production in the brain and liver, understanding these mechanisms requires a renewed search for the hypovolemic signals necessary for activating each behavior. Abstract figure legend Angiotensinogen is the precursor for angiotensin II, which is considered important for thirst and sodium appetite. In the brain, astrocytes express the angiotensinogen gene (Agt), but using GFAP-Cre to delete this gene from astrocytes did not reduce thirst or sodium appetite. In the liver, hepatocytes express this gene and produce circulating angiotensinogen. Using Alb-Cre to delete Agt from hepatocytes also did not reduce (and in fact enhanced) salt and water consumption. This article is protected by copyright. All rights reserved.

Even periconceptional alcohol consumption can have long-term consequences on heart health in the offspring.

Even periconceptional alcohol consumption can have long-term consequences on heart health in the offspring.

A Low Concentration of Citreoviridin Prevents Both Intracellular Calcium Deposition in Vascular Smooth Muscle Cell and Osteoclast Activation In Vitro

Vascular calcification (VC) and osteoporosis are age-related diseases and significant risk factors for the mortality of elderly. VC and osteoporosis may share common risk factors such as renin-angiotensin system (RAS)-related hypertension. In fact, inhibitors of RAS pathway, such as angiotensin type 1 receptor blockers (ARBs), improved both vascular calcification and hip fracture in elderly. However, a sex-dependent discrepancy in the responsiveness to ARB treatment in hip fracture was observed, possibly due to the estrogen deficiency in older women, suggesting that blocking the angiotensin signaling pathway may not be effective to suppress bone resorption, especially if an individual has underlying osteoclast activating conditions such as estrogen deficiency. Therefore, it has its own significance to find alternative modality for inhibiting both vascular calcification and osteoporosis by directly targeting osteoclast activation to circumvent the shortcoming of ARBs in preventing bone resorption in estrogen deficient individuals. In the present study, a natural compound library was screened to find chemical agents that are effective in preventing both calcium deposition in vascular smooth muscle cells (vSMCs) and activation of osteoclast using experimental methods such as Alizarin red staining and Tartrate-resistant acid phosphatase staining. According to our data, citreoviridin (CIT) has both an anti-VC effect and anti-osteoclastic effect in vSMCs and in Raw 264.7 cells, respectively, suggesting its potential as an effective therapeutic agent for both VC and osteoporosis.

Profoundal Effects of Microcystin-LR Induced Cardiotoxicity in Mammals

Eutrophication and climate change have raised obnoxious cyanobacterial blooms, which have become a global public health problem. The most dangerous cyanotoxin found in water bodies is microcystin (MC), a byproduct of cyanobacterial metabolism. Several studies suggest that in addition to the liver, the heart may be another target organ for MCs poisoning. Recent research indicates a clear link between MC exposure and cardiotoxicity, posing a risk to human cardiovascular health. The cardiovascular system, which includes all tissues, cells, blood, and vascular tissues of the heart, can be unswervingly affected by MCs, resulting in abnormal cardiovascular system structure and/or function. This review concludes that MC cardiotoxicity may be linked to protein phosphatase suppression and the contractile unit, generation of contractile force, the role of intercellular junction proteins, and the role of the angiotensin signaling pathway in cardiomyocytes.

Abstract 025: RNAseq And Bioinformatics Identify New Pathways In The Thick Ascending Limb (TAL) Involved In Fructose Induced Salt Sensitive Hypertension

Elevated fructose consumption is associated with hypertension in humans. In normal Sprague Dawley rats, a high fructose intake (20% fructose drinking water) induced salt sensitive hypertension. We found that fructose directly stimulates the apical Na/K/2Cl cotransporter NKCC2 in the thick ascending limb (TAL), and when consumed for more than 7 days, increases NKCC2 phosphorylation at Thre 96,101. SPAK and OSR1 kinases are known to phosphorylate NKCC2, but it is not known how fructose activates SPAK or OSR1. We hypothesized that fructose intake activates several signaling cascades in TALs that selectively stimulate SPAK. Using an antibody that recognizes activated SPAK and OSR1 (P-Ser 373 SPAK; Ser325 in OSR1), we found that 20% fructose (14 d) enhanced SPAK/OSR1 phosphorylation by 179±32% (p<0.05). This effect was specific for SPAK because phosphorylation of OSR1, immunoprecipitated from TALs, was not increased by fructose. To study the mechanism of SPAK activation, we isolated TALs from rats on control or 20% fructose diet for (14 d, n=6) and performed RNAseq. Over 12,000 genes were statistically compared and 500 were significantly different (p<0.05). Expression of some of the most highly upregulated genes (PRKRIP1 and SOCS3) was confirmed by Western blot in TALs. However, expression of upstream SPAK activators was unchanged by fructose (WNK1/3/4). We developed a targeted bioinformatics approach that included angiotensin signaling, nitric oxide and lipid metabolism, plus protein-protein interaction networks for SPAK. We identified PRKCQ (PKC Theta), a kinase upstream of SPAK, that was upregulated in TALs by fructose. In fructose fed rats, PRKCQ expression was 31±11% higher than control, as was Phospho-PRKCQ (223±45% increase, p<0.05). We then measured systolic BP (SBP) by telemetry in Dahl SS rats with genetic deletion of SPAK (SPAK KO). In WT Dahl SS rats, 4 weeks of fructose intake increased SBP by 25±4 mmHg (p<0.05), whereas in SPAK KO the increase in SBP was reduced (11±4 mmHg, p<0.05). We concluded that high fructose intake induces several prohypertensive signaling pathways in the TAL that lead to SPAK and NKCC2 activation. We identified PRKCQ as a potential activator of SPAK. Fructose induced hypertension in Dahl SS rats was in part mediated by SPAK.

The Genetics and Typical Traits of Thoracic Aortic Aneurysm and Dissection.

Genetic predisposition and risk factors such as hypertension and smoking can instigate the development of thoracic aortic aneurysm (TAA), which can lead to highly lethal aortic wall dissection and/or rupture. Monogenic defects in multiple genes involved in the elastin-contractile unit and the TGFβ signaling pathway have been associated with TAA in recent years, along with several genetic modifiers and risk-conferring polymorphisms. Advances in omics technology have also provided significant insights into the processes behind aortic wall degeneration: inflammation, epigenetics, vascular smooth muscle phenotype change and depletion, reactive oxygen species generation, mitochondrial dysfunction, and angiotensin signaling dysregulation. These recent advances and findings might pave the way for a therapy that is capable of stopping and perhaps even reversing aneurysm progression.

Dual therapy with an angiotensin receptor blocker and a JAK1/2 inhibitor attenuates dialysate-induced angiogenesis and preserves peritoneal membrane structure and function in an experimental CKD rat model.

Peritoneal dialysis (PD) is limited by reduced efficacy over time. We previously showed that a Janus kinase 1/2 inhibitor (JAK1/2i) reduced inflammation, hypervascularity and fibrosis induced by 4.25% dextrose dialysate (4.25%D) intraperitoneally (IP) infused for 10 days in rats with normal kidney function. JAK/STAT signalling mediates inflammatory pathways, including angiotensin signalling. We now tested the effect of long-term JAK1/2i and/or an angiotensin receptor blocker (ARB) on peritoneal membrane (PM) in polycystic kidneys (PCK) rats infused with 4.25%D. Except for controls, all PCK rats had a tunnelled PD catheter: (1) no infusions; (2) 4.25%D; (3) 4.25%D + JAK1/2i (5 mg/kg); (4) 4.25%D +losartan (5 mg/kg); and (5) 4.25%D + losartan +JAK1/2i (5 mg/kg each) IP BID × 16 weeks (N = 5/group). PM VEGFR2 staining areas and submesothelial compact zone (SMCZ) width were morphometrically measured. Peritoneal equilibration testing measured peritoneal ultrafiltration (UF) by calculating dialysate glucose at time 0 and 90 min (D/D0 glucose). 4.25%D caused hypervascularity, SMCZ widening, fibrosis and UF functional decline in PCK rats. Angiogenesis was significantly attenuated by JAK1/2i ± ARB but not by ARB monotherapy. Both treatments reduced SMCZ area. UF was preserved consistently by dual therapy (p < 0.05) but with inconsistent responses by monotherapies. Long-term JAK1/2i ± ARB reduced angiogenesis and fibrosis, and the combination consistently maintained UF. In clinical practice, angiotensin inhibition has been advocated to maintain residual kidney function. Our study suggests that adding JAK1/2i to angiotensin inhibition may preserve PM structure and UF.

Renin Production by Juxtaglomerular Cell Tumors and Clear Cell Renal Cell Carcinoma and the Role of Angiotensin Signaling Inhibitors

ObjectiveTo profile juxtaglomerular cell tumors (JXG) and histologic mimics by analyzing renin expression; to identify non-JXG renin-producing tumors in The Cancer Genome Atlas (TCGA) data sets; and to define the prevalence of hypertension (HTN) and patient outcomes with angiotensin signaling inhibitor (ASI) use in tumors of interest. Patients and MethodsThirteen JXGs and 10 glomus tumors (GTs), a histologic mimic, were evaluated for clinicopathologic features; TCGA data were analyzed to identify non-JXG renin-overexpressing tumors. An institutional registry was queried to determine the incidence of HTN, the use of ASIs in hypertensive patients, and the impact of ASIs on outcomes including progression-free survival (PFS) in a tumor type with high renin expression (clear cell renal cell carcinoma [CC-RCC] diagnosed between January 1, 2005, and December 31, 2012). ResultsWe found an association between renin production and HTN in JXG compared with GT. Analysis of TCGA data found that a subset of CC-RCCs overexpress renin relative to 29 other tumor types. Furthermore, analysis of our institutional registry revealed a high prevalence (64%) of HTN among 1203 patients treated with radical or partial nephrectomy for nonmetastatic CC-RCC. On multivariable Cox regression, patients with HTN treated with ASIs (34%) had improved PFS (hazard ratio, 0.76; 95% CI, 0.57 to 1.00; P=.05) compared with patients with HTN not treated with ASIs (30%). ConclusionThe identification of renin expression in a subset of CC-RCC may provide a biologic rationale for the high prevalence of HTN and improved PFS with ASI use in hypertensive patients with nonmetastatic CC-RCC.

Multiphoton Phosphorescence Quenching Microscopy Reveals Kinetics of Tumor Oxygenation during Antiangiogenesis and Angiotensin Signaling Inhibition.

The abnormal function of tumor blood vessels causes tissue hypoxia, promoting disease progression and treatment resistance. Although tumor microenvironment normalization strategies can alleviate hypoxia globally, how local oxygen levels change is not known because of the inability to longitudinally assess vascular and interstitial oxygen in tumors with sufficient resolution. Understanding the spatial and temporal heterogeneity should help improve the outcome of various normalization strategies. We developed a multiphoton phosphorescence quenching microscopy system using a low-molecular-weight palladium porphyrin probe to measure perfused vessels, oxygen tension, and their spatial correlations in vivo in mouse skin, bone marrow, and four different tumor models. Further, we measured the temporal and spatial changes in oxygen and vessel perfusion in tumors in response to an anti-VEGFR2 antibody (DC101) and an angiotensin-receptor blocker (losartan). We found that vessel function was highly dependent on tumor type. Although some tumors had vessels with greater oxygen-carrying ability than those of normal skin, most tumors had inefficient vessels. Further, intervessel heterogeneity in tumors is associated with heterogeneous response to DC101 and losartan. Using both vascular and stromal normalizing agents, we show that spatial heterogeneity in oxygen levels persists, even with reductions in mean extravascular hypoxia. High-resolution spatial and temporal responses of tumor vessels to two agents known to improve vascular perfusion globally reveal spatially heterogeneous changes in vessel structure and function. These dynamic vascular changes should be considered in optimizing the dose and schedule of vascular and stromal normalizing strategies to improve the therapeutic outcome.

Abstract LB557: Multiphoton phosphorescence quenching microscopy reveals kinetics of tumor oxygenation during anti-angiogenesis and angiotensin signaling inhibition

Abstract Purpose: The abnormal function of tumor blood vessels causes hypoxia fueling disease progression and conferring treatment resistance. The local level of oxygen experienced by a cell will determine its response, making it critical to understand tissue oxygen levels with a spatial resolution on the order of the size of a cell. While microenvironment normalization strategies alleviate global hypoxia, how local oxygen levels change are not known because there are no in vivo techniques to longitudinally assess tumor vessels and interstitial oxygen in tumors with sufficient resolution. Understanding the heterogeneity of oxygen levels after microenvironmental normalization will help improve the efficacy of various normalization strategies. Experimental Design: We developed a multiphoton phosphorescence quenching microscopy system using a low-molecular weight palladium porphyrin probe to measure perfused vessels, oxygen tension and their spatial correlations in vivo in mouse skin, bone marrow, and tumors. Further, we measured the temporal and spatial changes in oxygen and vessel perfusion in tumors in response to microenvironmental normalization. Results: We found that vessel function was highly dependent on tumor type. Although some tumors had vessels with greater oxygen carrying ability than normal skin, most tumors had inefficient vessels. Further, inter-vessel heterogeneity in tumors coincided with heterogeneous response to microenvironmental normalizing agents. Using both vascular and stromal normalizing agents, we show that spatial heterogeneity in oxygen levels persist, even with global reductions in hypoxia. Conclusions: We present the first study to examine the high-resolution spatial and temporal response of tumor vessels to two agents known to improve vascular perfusion globally. Our measurements demonstrate that the heterogeneities in the local imbalance of pro- and anti-angiogenic signaling lead to spatially heterogeneous changes in vessel structure and function. Microscale dynamic vascular changes should be considered in optimizing the dose and schedule of microenvironment normalizing therapies to improve function. Citation Format: John Martin, Ryan Lanning, Dai Fukumura, Timothy Padera, Rakesh Jain. Multiphoton phosphorescence quenching microscopy reveals kinetics of tumor oxygenation during anti-angiogenesis and angiotensin signaling inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB557.

Antihypertensive Drugs and Cancer Risk.

Hypertension is the most prevalent comorbidity in cancer patients. Consequently, many cancer patients are prescribed antihypertensive drugs before cancer diagnosis or during cancer treatment. However, whether antihypertensive drugs affect the incidence, treatment efficacy, or prognosis of cancer remains unanswered. For instance, renin-angiotensin and β-adrenergic signaling may be involved not only in blood pressure elevation but also in cell proliferation, angiogenesis, and tissue invasion. Therefore, the inhibition of these pathways may have beneficial effects on cancer prevention or treatment. In this article, we reviewed several studies regarding antihypertensive drugs and cancer. In particular, we focused on the results of clinical trials to evaluate whether the use of antihypertensive drugs affects future cancer risk and prognosis. Unfortunately, the results are somewhat inconsistent, and evidence demonstrating the effect of antihypertensive drugs remains limited. We indicate that the heterogeneity in the study designs makes it difficult to clarify the causal relationship between antihypertensive drugs and cancer. We also propose that additional experimental studies, including research with induced pluripotent cells derived from cancer patients, single-cell analyses of cancer cell clusters, and clinical studies using artificial intelligence electronic health record systems, might be helpful to reveal the precise association between antihypertensive drugs and cancer risk.

Gq Signaling in the Placental Syncytiotrophoblast Layer During Preeclampsia

Preeclampsia is a pregnancy‐associated cardiovascular disorder characterized by hypertension and proteinuria after 20 weeks of gestation. Generalized cellular ‘stress’ (oxidative, mitochondrial, etc.) within the syncytiotrophoblast (STB) layer of placenta is theorized to drive its pathogenesis. Hormones implicated in preeclampsia such as angiotensin, endothelin, and vasopressin signal via receptors that typically couple to the Gq second‐messenger cascade, and Regulator of G protein Signaling‐2 (RGS2) buffers this signaling. We have published that RGS2 expression is decreased in human preeclamptic placenta, and reducing RGS2 expression in placenta is sufficient to cause development of key features of this disorder in mice. Unpublished in situ hybridization data indicate that in both humans and mice, RGS2 is present in the STB layer – and that RGS2 expression in the STB layer is reduced during preeclampsia in humans. Collectively, these findings lead us to generally hypothesize that excess Gq signaling specifically within the STB layer, whether due to excessive hormonal activation or loss of RGS2‐mediated buffering, causes STB‐Stress and thereby contributes to the pathogenesis of preeclampsia. Therefore, the objective of this study was to test whether artificial, exogenous activation of Gq signaling only within STB cells is sufficient to induce placental and maternal phenotypes of preeclampsia in mice.CAG‐FLEX‐hM3Dq+/+ (Gαq DREADD, Jax 026943) or C57BL/6J dams were bred with Gcm1‐Cre+/‐ sires (Jax 026625) or non‐transgenic littermates to elicit STB‐restricted hM3Dqexpression in ≍50% or 0% of placentas. The synthetic DREADD ligand clozapine N‐oxide (CNO) or saline vehicle was administered (2 mg/kg/d, ip) mid‐gestation (GD 12.5‐14.5). Placental and maternal phenotypes were compared between Cre– and Cre+ placentas within a dam, CNO‐ vs saline‐injected double‐transgenic dams, and double‐ vs single/non‐transgenic dams treated with CNO. Activation of Gq in the STB layer caused maternal proteinuria (n=4‐9, 49±6 mg/day vs 28±4 mg/day; p=0.01). Labyrinth vascularization, assessed by percentage of CD31+ area, was reduced with Gq activation (n=5, Cre+ 21±1%, Cre– 27±2%; p=0.01), while other regions remained unaffected (Decidua: Cre+ 14±4%, Cre– 14±3%; Junctional Zone: Cre+ 11±4%, Cre– 12±3%). Possible reductions in placental mass (n=5 Cre+ 0.12±0.01g, Cre– 0.15±0.01g; p=0.06), and placental vascular endothelial growth factor protein levels (n=6‐7 117±67 ng/g vs 151±12 ng/g; p=0.06) were noted, but no obvious trend in fetal growth restriction was observed (n=5 Cre+ 0.21±0.06g, Cre– 0.29±0.04g). These data support the pathological significance of excess Gq signaling specifically within the STB layer. Ongoing studies are aimed at further characterizing maternal phenotypes (blood pressure, circulating factors) in these models, and the synergistic effects of simultaneous STB‐specific deletion of RGS2 upon sensitivity to Gq stimulation in this cell type.

The Polysaccharide of Ligustrum Lucidum Ait. Protected from Renal Fibrosis by Interfering with Angiotensin II Signaling

BackgroundA number of preclinical advances have indicated the cellular and molecular mechanisms underlying renal fibrosis, such as the signaling of angiotensin II (Ang II), which is a bioactive peptide in renin‐angiotensin system. As one of kidney‐tonifying herbs, Fructus Ligustri Lucidi (FLL), the fruit of Ligustrum lucidum Ait. (Oleaceae) recorded as a tonic and dietary supplement, is a commonly prescribed component in traditional kidney‐tonifying herbal formula. This study aimed to clarify the polysaccharide component in FLL and investigate its potential role in preservation against renal fibrosis.MethodsThe crude polysaccharide of FLL was prepared and deproteinized by Sevag reagent. After lyophilization, the DEAE‐cellulose DE52 column and the Sephacryl S‐200 HR column were used for further isolation and purification of homogenous polysaccharide. The mice with unilateral ureteral obstruction (UUO) underwent daily intraperitoneal injection with FLL polysaccharide starting 7 days before UUO surgery until day 7 after surgery. The murine mesangial SV40‐MES13 cells were treated with vehicle, Ang II (10‐7 M) either with the absence and presence of angiotensin type I receptor blocker (ARB) (10‐6M), or with low dose (50 μg/mL, Poly‐L) and high dose (200 μg/mL, Poly‐H) of FLL polysaccharide.ResultsThe purified homogenous polysaccharide (Poly) was explored from FLL and the carbohydrate content was 97.45%. A hypothetical structure for Poly was proposed considering the comprehensive data of methylation, monosaccharides, and NMR analyses. Treatment of UUO mice with Poly decreased kidney index and ameliorated glomerular sclerosis and interstitial fibrosis, as well as down‐regulated the expression of profibrogenic factor VEGF and matrix fibrotic protein fibronectin (FN). Furthermore, as the same effect to ARB, the pre‐incubation with Poly alleviated the Ang II‐induced up‐regulation of FN in mesangial cells by immunofluoresence staining. The protein expressions of FN and proinflammatory factors like MCP‐1 and Rantes were significantly lower in Poly‐treated cell group than those in Ang II treatment group.ConclusionThe polysaccharide of Ligustrum lucidum Ait. was accurately explored with structure clarification. This polysaccharide component repressed angiotensin II‐induced fibrotic phenotype of renal mesangial cells and exerted beneficial effects on kidney of UUO mice.

Abstract 292: LRP1 Prevents Aortic And SMA Aneurysms By Modulating Excessive Ang-II Signaling

Objectives: LRP1 (low-density lipoprotein receptor-related protein 1) is known to contribute to vascular homeostasis and plays a protective role against the development of aneurysms. LRP1 has specifically been associated with abdominal aortic aneurysms in GWAS studies. We and others have also previously reported that mice with a conditional smooth muscle cell (SMC) knock-out of LRP1 (smLRP1-/-) exhibit vascular wall dysfunction and aortic dilation. In this study, we sought to investigate the molecular mechanisms by which LRP1 regulates vessel wall integrity in hopes of identifying potential therapeutic targets against aneurysm progression. Approach and Results: Analysis of proteomic data of the descending thoracic aorta, abdominal aorta, and superior mesenteric artery (SMA) of smLRP1-/- mice confirmed excess activation of the angiotensin signaling pathway. To verify these observations, we designed experiments to determine if losartan, an angiotensin-II receptor blocker, could prevent aneurysm progression in smLRP1-/- mice. Following treatment, we analyzed the aortic vasculature from LRP1+/+ and smLRP1-/- adult mice (16-weeks of age) with or without treatment. Without losartan, smLRP1-/- mice developed spontaneous aortic and SMA aneurysms as demonstrated by increased vessel dilation, vessel medial thickening and significant fragmentation of the elastic lamina. We found that when treated with losartan, smLRP1-/- mice had a complete restoration of medial layer thickness and a partial decrease of elastin fragmentation compared to untreated smLRP1-/- mice. Furthermore, losartan completely blocked SMA aneurysm formation in smLRP1-/- mice. Conclusions: Our findings suggest a critical role for LRP1 in maintaining vascular homeostasis and preventing aneurysm formation through its regulation of the angiotensin signaling pathway. Further studies will need to investigate the connection between LRP1 and the angiotensin signaling pathway in aneurysm formation to further understand the complex pathophysiology and potentially develop effective therapeutic targets for this disease.

Identification of Novel Molecular Targets of Four Microcystin Variants by High-Throughput Virtual Screening

Highly toxic microcystins (MCs) perform complex interactions with many proteins that induce cellular dysregulation, leading to the development of several diseases including cancer. There is significant diversity and chemical complexity among MC congeners, which makes it difficult to identify structure-dependent toxicity outcomes and their long-term effects. The aim of this study was to exploratory identify likely molecular targets of the main MC variants (MC-LA, MC-LR, MC-RR, and MC-LY) by conducting a computational binding affinity analysis using AutoDock Vina to evaluate the interaction of the toxins with 1000 proteins related to different biological functions. All four variants showed strong in silico interactions with proteins that regulate metabolism/immune system, CD38 (top scoring hit, −11.5 kcal/mol); inflammation, TLR4 (−11.4 kcal/mol) and TLR8 (−11.5 kcal/mol); neuronal conduction, BChE; renin–angiotensin signaling, (ACE); thyroid hormone homeostasis (TTR); and cancer-promoting processes, among other biochemical activities. The results show MCs have the potential to bind onto distinct molecular targets which could generate biochemical alterations through a number of signal transduction pathways. In short, this study broadens our knowledge about the mechanisms of action of different variants of microcystins and provides information for future direct experimentation.