ACE Activity Research Articles

Characterizations of angiotensin-converting enzyme-2 (ACE2) peptidase activity

Angiotensin (Ang) II (1-8) is a potent vasoconstrictor known for its role in hypertension. Angiotensin-converting enzyme (ACE2) converts Ang II (1-8) to a vasodilator Ang (1-7) by removing the carboxy-terminal Phe. ACE2 more recently gained attention as the receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that caused the coronavirus disease 2019 (COVID-19) pandemic. Given the pathophysiological importance of ACE2, the present study examined the mechanism of ACE2 catalytic activity by comparing the ability of angiotensin molecules of various lengths to compete with the artificial fluorogenic substrate. The Fluorimetric SensoLyte 390 ACE2 Activity Assay uses an Mca/Dnp fluorescence resonance energy transfer peptide as the substrate. Results showed that the natural substrate Ang II (1-8) competed with the fluorogenic substrate, reducing the fluorescence signals. Deletion of C-terminal Phe resulted in the loss of the ability to compete with the artificial substrate, as shown by the actions of Ang (1-7), Ang (2-7), and Ang (5-7). By contrast, the loss of N-terminal Asp potentiated the ability to compete with the substrate as seen by the action of Ang III (2-8). However, the loss of two amino acids (Asp-Arg) from the N-terminus reduced the ability to compete with the substrate as observed by the actions of Ang IV (3-8) and Ang (5-8). Ang I (1-10) and Ang (1-9) did not strongly compete with the substrate. Interestingly, shorter peptides Ang (1-5) and Ang (1-4) potentiated the ACE2 activity. These results suggest that Ang II and Ang III are the best natural substrates for ACE2.

Polyphenol-rich Ocimum gratissimum leaf extract attenuates angiotensin-converting enzyme activity and impaired endothelial vascular function in diabetic rats

Endothelial vascular dysfunctions are prevalent among diabetic patients, significantly impacting their quality of life and prognosis. This study examined the effects of polyphenol-rich extracts from Ocimum gratissimum leaves on oxidative stress markers, serum lipid profiles, and angiotensin-converting enzyme activity in diabetic cardiac tissue. Forty Wistar rats (150–220 g) were divided into five groups: normal control, diabetic control, low-dose Ocimum gratissimum (122.46 mg/kg), medium-dose Ocimum gratissimum (244.98 mg/kg), and a positive control (standard diabetic drug). All rats except the normal control group were made diabetic via an intraperitoneal injection of 50 mg/kg streptozotocin, followed by 28 days of extract administration. Diabetes induction led to a significant (p<0.05) disruptions in lipid profiles, oxidative stress markers, and ACE activity. Treatment with Ocimum gratissimum extracts at both doses significantly (p<0.05) decreased triglyceride, low-density lipoprotein cholesterol, and very-low-density lipoprotein cholesterol levels while increasing high-density lipoprotein cholesterol. Lipid peroxidation marker, malondialdehyde, was significantly (p<0.05) decreased, and antioxidant enzyme activities significantly (p<0.005) improved. ACE activity was significantly (p<0.05) reduced, approaching control levels. These results suggest that the polyphenol-rich extract of Ocimum gratissimum exerts antioxidant and cardio-protective effects, improving vascular functions in diabetic rats by improving lipid profiles, reducing oxidative stress, and suppressing ACE activity.

Potential Beneficial Role of Nitric Oxide in SARS-CoV-2 Infection: Beyond Spike-Binding Inhibition

SARS-CoV-2, the causative virus for the COVID-19 disease, uses its spike glycoprotein to bind to human ACE2 as a first step for viral entry into the cell. For this reason, great efforts have been made to find mechanisms that disrupt this interaction, avoiding the infection. Nitric oxide (NO) is a soluble endogenous gas with known antiviral and immunomodulatory properties. In this study, we aimed to test whether NO could inhibit the binding of the viral spike to ACE2 in human cells and its effects on ACE2 enzymatic activity. Our results show that ACE2 activity was decreased by the NO donors DETA-NONOate and GSNO and by the NO byproduct peroxynitrite. Furthermore, we found that DETA-NONOate could break the spike–ACE2 interaction using the spike from two different variants (Alpha and Gamma) and in two different human cell types. Moreover, the same result was obtained when using NO-producing murine macrophages, while no significant changes were observed in ACE2 expression or distribution within the cell. These results support that it is worth considering NO as a therapeutic agent for COVID-19, as previous reports have suggested.

ACE and ACE2 activities and polymorphisms assessment: A populational study from Ipaussu (SP, Brazil) during the COVID-19 pandemic

AimThe angiotensin-converting enzyme 2 (ACE2) and its homolog, the angiotensin converting enzyme 1 (ACE), are involved in COVID-19 physiopathology. Alterations in the enzymatic structure, expression, and/or activity may influence the risk of infection and severity of disease. For this reason, we aimed to identify different allelic forms of ACE2 G8790A and ACE I/D polymorphisms in a Brazilian cohort and evaluate their impact on ACE and ACE2 activities and their association with COVID-19 susceptibility and severity. Main methodsA total of 549 COVID-19-negative and 270 COVID-19-positive participants from Ipaussu, Sao Paulo, Brazil, were recruited. ACE2 and ACE activities were measured by fluorogenic assays using MCA-Ala-Pro-Lys(Dnp) as the substrate for ACE2 and Z-Phe-His-Leu-OH (Z-FHL) and Hippuryl-His-Leu-OH (h−HL) as substrates for ACE. Genomic DNA was extracted from EDTA-peripheral blood, and the regions of the genes containing ACE2 G8790A and ACE I/D polymorphisms were amplified by PCR-restriction fragment length polymorphism and real-time PCR, respectively. Key findingsThe G allele of ACE2 G8790A polymorphism and D allele of ACE I/D polymorphism are associated with increased ACE and ACE2 activities. ACE activity ratio (Z-FHL/h-HL), an inflammatory marker, is increased in women with GG genotype and COVID-19-positive diagnosis. SignificanceFor the first time, it was demonstrated that in females, the GG genotype is associated with increased ACE activity ratio (Z-FHL/h-HL) in the COVID-19-positive group. Elevated ACE activity ratio (Z-FHL/h-HL) is highly linked to inflammation and may justify the associations between the G genotype and COVID-19 severity of symptoms and outcomes.

Predictors of COVID-19 severity among a cohort of Egyptian patients

BackgroundAs the outbreak of COVID-19 progresses, prognostic markers for the identification of high-risk individuals are urgently needed. The angiotensin system is implicated in the pathogenesis of COVID-19 as ACE2 is the cellular receptor for SARS-COV-2 virus, and expression of the ACE2 gene could regulate an individual’s susceptibility to infection. In addition, the balance between ACE and ACE2 activity may play a role in the severity of COVID-19.Aim of workThe aim of the work is to explore the role of ACE1 I/D and ACE2 G8790A gene variants and serum ACE l/ACE2 ratio as risk factors for severity of COVID-19 infection.MethodsOne hundred and eighty COVID-19 patients were divided into three groups: mild (60 patients), moderate (60 patients), and severe (60 patients). The enzyme levels of ACE and ACE2 were measured by ELISA. ACE I/D (rs4646994) was assayed using PCR and ACE2 (rs2285666) gene variant was determined using real-time PCR.ResultsACE/ACE2 ratio was significantly lower in the mild group than in the moderate-to-severe group (P < 0.001). GG (reference) genotype and G allele of ACE2 were more frequent in mild group, AA (variant) genotype, and A allele were more frequent in severe group (P value < 0.001). In the multiple logistic regression, COVID-19 severity was associated with older age (> 50y) (OR 10.4, 95% CI 3.8–28.4, P < 0.001), comorbidities (OR 8.2, 95% CI 1.6–42.1, P 0.012), and higher ACE/ACE2 ratio (OR 8.3, 95% CI 3.7–18.6 P < 0.001) were independent significant predictors of severity. Haplotype analysis revealed that patients with D allele of the ACE gene combined with the A allele of the ACE2 gene had nearly double the risk of having severe COVID infection (OR = 1.9, 95% CI 1.1–3.5, P = 0.024).ConclusionOld age (> 50 years), presence of comorbidities, and a high ACE/ACE2 ratio are recognized as pivotal predictors of COVID-19 severity.

Hypertension and Cognitive Dysfunction in a Pregnant Rat Model of PE; a Role for CD4+ T Cells.

Preeclampsia (PE) is associated with hypertension (HTN) during pregnancy and activated CD4+ T cells, inflammatory cytokines, and autoantibodies to the angiotensin II type I receptor (AT1-AA). Having had COVID-19 (CV) during pregnancy is associated with an increased incidence of a PE-like phenotype. Both PE and CV have long-lasting neurological implications and studies show that nonpregnant COVID patients produce AT1-AA. We have shown that CD4+ T cells from PE women cause a PE phenotype in nude athymic rats. In this study, we sought to examine the role of CD4+ T cells from PE with a CV History (Hx) to contribute to a PE phenotype and to determine the importance of CD4+ T cells in cognitive dysfunction during pregnancy. At delivery, blood and placentas were collected, and one million placental CD4+ T cells from each PE and each normotensive patient, with (NT) or without (NP) a CV (Hx) during pregnancy, were isolated, purified, and injected i.p. into a gestational day (GD) 12 pregnant nude athymic rat (one patient/rat). At GD19, blood pressure (MAP) and circulating factors were assessed in recipient rats. Cognitive function and memory were assessed using Novel Object Recognition and Barnes Maze tests, respectively. Placental ACE-2 activity and AT1-AA were measured from COVID Hx patients. A one- or two-way ANOVA with Bonferroni's multiple comparisons test was used for statistical analysis. Blood pressure was increased in patients with PE, with or without COVID, compared to NT patients. There were no significant changes in placental ACE activity in patients with COVID Hx with or without PE. AT1-AA was elevated in PE patients and in both PE and NT COVID Hx compared to control NP. In pregnant recipient rats, MAP increased in CV Hx PE (113±2, n=8) compared to CV Hx NT (101±5, n=6). PE and PE CV Hx CD4+ T Cell recipient rats exhibited impaired memory and cognitive dysfunction (p < 0.05), compared to control groups. Recipient rats of PE CV Hx CD4+ T cells had elevated AT1-AA compared to NT CV Hx recipients. Both COVID Hx groups and recipients of PE CD4+ T cells had elevated TNF alpha compared to NP. Our findings indicate that pregnant patients with a Hx of COVID during pregnancy produce AT1-AA, with or without PE. Recipients of CD4+ T cells from PE with or without a CV Hx during pregnancy cause HTN and elevated AT1-AA. TNF-α is elevated in PE and in CV Hx NT and PE recipients. Interestingly, recipients of T cells from PE patients with or without a Hx of CV had worse cognitive function during pregnancy, compared to recipient rats of NP CD4+ T cells. These data demonstrate the importance of CD4+ T cells in HTN and impaired neurological function during PE in the presence or absence of a prior COVID-19 infection during pregnancy.

Circulating ACE2 Activity and Gas6 Are Increased in Patients Diagnosed with COVID-19

Circulating ACE2 Activity and Gas6 Are Increased in Patients Diagnosed with COVID-19

From Sea to Lab: Angiotensin I-Converting Enzyme Inhibition by Marine Peptides-Mechanisms and Applications.

To reveal potent ACE inhibitors, researchers screen various bioactive peptides from several sources, and more attention has been given to aquatic sources. This review summarizes the recent research achievements on marine peptides with ACE-inhibitory action and application. Marine peptides are considered excellent bioactives due to their large structural diversity and unusual bioactivities. The mechanisms by which these marine peptides inhibit ACE include competitive binding to ACEs' active site, interfering with ACE conformational changes, and avoiding the identification of substrates. The unique 3D attributes of marine peptides confer inhibition advantages toward ACE activity. Because IC50 values of marine peptides' interaction with ACE are low, structure-based research assumes that the interaction between ACE and peptides increased the therapeutic application. Numerous studies on marine peptides focused on the sustainable extraction of ACE-inhibitory peptides produced from several fish, mollusks, algae, and sponges. Meanwhile, their potential applications and medical benefits are worth investigating and considering. Due to these peptides exhibiting antioxidant, antihypertensive, and even antimicrobial properties simultaneously, their therapeutic potential for cardiovascular disease and other illnesses only increases. In addition, as marine peptides show better pharmacological benefits, they have increased absorption rates and low toxicity and could perhaps be modified for better stability and bioefficacy. Biotechnological advances in peptide synthesis and formulation have greatly facilitated the generation of peptide-based ACE inhibitors from marine sources, which subsequently offer new treatment models. This article gives a complete assessment of the present state of knowledge about marine organism peptides as ACE inhibitors. In addition, it emphasizes the relevance of additional investigation into their mechanisms of action, the optimization of manufacturing processes, and assessment in in vivo, preclinical, and clinical settings, underlining the urgency and value of this study. Using marine peptides for ACE inhibition not only broadens the repertory of bioactive compounds but also shows promise for tackling the global health burden caused by cardiovascular diseases.

P137 ACE AND ACE 2 ENZYMES POLYMORPHISM IN DIFFERENT CLINICAL COVID-19 MANIFESTATIONS IN HOSPITAL-ADMITTED PATIENTS

Introduction: The affinity of SARS-CoV-2 for the Angiotensin Converting Enzyme 2 (ACE2), component of the Renin-Angiotensin System (RAS), is responsible for the COVID-19 virus internalization, and the ACE and ACE2 genes polymorphisms may contribute for the disease outcome. Objective: To correlate the I/D ACE and the G8790A ACE2 polymorphisms and their enzymatic activity to the virus susceptibility and the disease's clinical severity. Methods: 408 patients from Alfa Hospital, Recife – PE, were assessed. ACE activity was measured by fluorometry and the real time PCR technique was used to assess ACE's DD, ID, and II polymorphisms. Results: 71.9% of COVID-19 affected patients needed hospitalization, with 56.8% being male ranging from 40 to 59 years old. In the positive group, there were more patients with blood hypertension (80.6% vs 19.4%), diabetes (88.2% vs 11.8%), and obesity (87.5% vs 12.5%). ACE activity was higher in positive patients (46.5 vs 43.5 nmol/mL/min), with greater prevalence of the DD genotype, 85.6% of frequency between negatives and positives. When it comes to DD genotype, ACE activity was higher (48.5 nmol/mL/min). In patients with blood hypertension, ID genotype was more frequent than the DD one. Conclusion: The interaction of genetic and risk factors may lead to different COVID-19 symptomatology. The scientific literature states that ACE polymorphism may contribute for the development of blood hypertension, as the DD genotype being the susceptible one for developing cardiovascular complications by the higher concentration of Angiotensin II converted from Angiotensin I by ACE, increasing the hypertensive effects in relation to the anti-hypertensive ones of Angiotensin 1-7. The positive group showed more incidence of blood hypertension, diabetes and obesity, as well as higher frequency of the DD genotype, which is already established in literature to lead to blood hypertension due to increased ACE activity. From the observed in these results, it is suggested a correlation between ACE polymorphism and the factors that may aggravate COVID-19

Abstract P207: Regulation of Fetal-Placental ACE and ACE2 in COVID-19 Exposed Pregnancies Compared to Hypertensive and Healthy Pregnancies

Introduction: Higher risks of preterm birth and fetal growth restriction are observed in COVID-19 pregnancies. The infection mechanism, linked to a potential depletion of the cardioprotective protein ACE2, which serves as a receptor for SARS-CoV-2, could pose additional risks for mothers and fetuses. An ACE2/ACE imbalance, favoring ACE, has been seen in hypertensive (HT) pregnancies and is linked to poor outcomes, including pre-eclampsia. This study aims to assess whether similar changes in ACE and ACE2 regulation in placentas and umbilical cord blood occur in COVID-19 compared to HT and healthy (Ctrl) pregnancies, and whether this imbalance is associated with impaired vascular structure. Methods: A retrospective cohort study recruited 77 pregnancies (25 COVID-19, 16 HT, 36 Ctrl) at Montreal Hospital Sacré-Coeur. Placental infarction was assessed in histological sections, umbilical cord fibrosis by Masson's trichrome staining, and placental ACE2 content by immunohistochemistry. ACE and ACE2 activity were measured by fluorometric assay in umbilical cord plasma. Data are presented as mean 95% CI. Linear regression was used for correlations, Kruskal-Wallis and Mann-Whitney tests for group comparisons. Results: Maternal age, gestational age, and the proportion of male/female fetuses were similar between groups. Ctrl group had lower rates of C-section delivery, obesity, and gestational diabetes compared to COVID-19 and HT pregnancies. Although ACE2 content in placentas was reduced in HT pregnancies, the COVID-19 group had significantly higher content compared to HT and Ctrl pregnancies (23.4 CI=20.4-26.4 vs. 15.5 CI=9.7-21.3 and 17.6 CI=15.1-20.1, respectively, p&lt;0.01). The ACE2/ACE activity ratio in cord blood was significantly reduced in COVID-19 and HT groups compared to Ctrl (3.1 CI=2.4-3.6, 2.5 CI=1.7-3.1, and 4.1 CI=3.5-4.8, p&lt;0.01), indicating an imbalance favoring ACE activity in HT and COVID-19 groups. The ACE2/ACE ratio negatively correlated with umbilical cord fibrosis (slope=-3.1 CI= -6.1 to -0.1, p=0.04) and was significantly lower in placentas with tissue infarction (2.5 CI=1.2-3.8 vs. 4.6 CI=3.8-5.3, p&lt;0.01). Conclusion: HT pregnancies have reduced ACE2 content and an ACE2/ACE activity imbalance in cord blood. COVID-19 pregnancies show a similar imbalance in cord blood but significantly higher ACE2 content in the placenta. This imbalance is associated with structural changes in fetal-placental vessels, suggesting a link to poor pregnancy outcomes.

Investigation of the regulatory effect of α-chymotrypsin-assisted hydrolysate from Sebastes schlegelii on blood pressure through in vitro, in silico ACE inhibitory activity, and in vivo spontaneously hypertensive rat hypertensive model

This study aimed to screen peptides with antihypertensive effects from the α-chymotrypsin hydrolysate of Sebastes schlegelii (SSA). SSA demonstrated ACE inhibitory activity with an IC50 value of 0.062 ± 0.001 mg/mL. The SSA significantly reduced body weight and systolic blood pressure in the SHR spontaneously hypertensive rat (SHR) model and improved hypertension-induced vasopathy and interstitial fibrosis in heart and vascular tissues, indicating the presence of ACE inhibitory peptides contributing to cardiovascular health. Peptide composition analysis identified fractions of SSA with potent ACE inhibitory activity, particularly those with molecular weights of 5 kDa or less. Further evaluation of ACE activity using Sephadex G-10 separated SSA fractions led to the amino acid sequence analysis of the most effective fraction (SSA-F1). Molecular docking simulations predicted that peptides from SSA-F1 inhibit ACE activity by binding to its active sites. This research suggests the potential of peptides from S. schlegelii for clinical hypertension treatment.

Super-Resolution Imaging Reveals the Mechanism of Endosomal Acidification Inhibitors Against SARS-CoV-2 Infection.

In this study, super-resolution structured illumination microscope (SIM) was used to analyze molecular mechanism of endocytic acidification inhibitors in the SARS-CoV-2 pandemic, such as Chloroquine (CQ), Hydroxychloroquine (HCQ) and Bafilomycin A1 (BafA1). We fluorescently labeled the SARS-CoV-2 RBD and its receptor ACE2 protein with small molecule dyes. Utilizing SIM imaging, the real-time impact of inhibitors (BafA1, CQ, HCQ, Dynasore) on the RBD-ACE2 endocytotic process was dynamically tracked in living cells. Initially, the protein activity of RBD and ACE2 was ensured after being labeled. And then our findings revealed that these inhibitors could inhibit the internalization and degradation of RBD-ACE2 to varying degrees. Among them, 100 nM BafA1 exhibited the most satisfactory endocytotic inhibition (~63.9 %) and protein degradation inhibition (~97.7 %). And it could inhibit the fusion between endocytic vesicles in the living cells. Additionally, Dynasore, a widely recognized dynein inhibitor, also demonstrated cell acidification inhibition effects. Together, these inhibitors collectively hinder SARS-CoV-2 infection by inhibiting both the viral internalization and RNA release. The comprehensive evaluation of pharmacological mechanisms through super-resolution fluorescence imaging has laid a crucial theoretical foundation for the development of potential drugs to treat COVID-19.

Activation of angiotensin converting enzyme 2 promotes hippocampal neurogenesis via activation of Wnt/β-catenin signaling in hypertension

Hypertension-induced brain renin-angiotensin system (RAS) activation and neuroinflammation are hallmark neuropathological features of neurodegenerative diseases. Previous studies from our lab have shown that inhibition of ACE/Ang II/AT1R axis (by AT1R blockers or ACE inhibitors) reduced neuroinflammation and accompanied neurodegeneration via up-regulating adult hippocampal neurogenesis. Apart from this conventional axis, another axis of RAS also exists i.e., ACE2/Ang (1–7)/MasR axis, reported as an anti-hypertensive and anti-inflammatory. However, the role of this axis has not been explored in hypertension-induced glial activation and hippocampal neurogenesis in rat models of hypertension. Hence, in the present study, we examined the effect of ACE2 activator, Diminazene aceturate (DIZE) at 2 different doses of 10 mg/kg (non-antihypertensive) and 15 mg/kg (antihypertensive dose) in renovascular hypertensive rats to explore whether their effect on glial activation, neuroinflammation, and neurogenesis is either influenced by blood-pressure. The results of our study revealed that hypertension induced significant glial activation (astrocyte and microglial), neuroinflammation, and impaired hippocampal neurogenesis. However, ACE2 activation by DIZE, even at the low dose prevented these hypertension-induced changes in the brain. Mechanistically, ACE2 activation inhibited Ang II levels, TRAF6-NFκB mediated inflammatory signaling, NOX4-mediated ROS generation, and mitochondrial dysfunction by upregulating ACE2/Ang (1–7)/MasR signaling. Moreover, DIZE-induced activation of the ACE2/Ang (1–7)/MasR axis upregulated Wnt/β-catenin signaling, promoting hippocampal neurogenesis during the hypertensive state. Therefore, our study demonstrates that ACE2 activation can effectively prevent glial activation and enhance hippocampal neurogenesis in hypertensive conditions, regardless of its blood pressure-lowering effects.

Effect of Diminazene Aceturate, an ACE2 activator, on platelet CD40L signaling induced glial activation in rat model of hypertension

Hypertension causes platelet activation and adhesion in the brain resulting in glial activation and neuroinflammation. Further, activation of Angiotensin-Converting Enzyme 2/Angiotensin (1–7)/Mas Receptor (ACE2/Ang (1–7)/MasR) axis of central Renin-Angiotensin System (RAS), is known to reduce glial activation and neuroinflammation, thereby exhibiting anti-hypertensive and anti-neuroinflammatory properties. Therefore, in the present study, the role of ACE2/Ang (1–7)/MasR axis was studied on platelet-induced glial activation and neuroinflammation using Diminazene Aceturate (DIZE), an ACE2 activator, in astrocytes and microglial cells as well as in rat model of hypertension. We found that the ACE2 activator DIZE, independently of its BP-lowering properties, efficiently prevented hypertension-induced glial activation, neuroinflammation, and platelet CD40-CD40L signaling via upregulation of ACE2/Ang (1–7)/MasR axis. Further, DIZE decreased platelet deposition in the brain by reducing the expression of adhesion molecules on the brain endothelium. Activation of ACE2 also reduced hypertension-induced endothelial dysfunction by increasing eNOS bioavailability. Interestingly, platelets isolated from hypertensive rats or activated with ADP had significantly increased sCD40L levels and induced significantly more glial activation than platelets from DIZE treated group. Therefore, injection of DIZE pre-treated ADP-activated platelets into normotensive rats strongly reduced glial activation compared to ADP-treated platelets. Moreover, CD40L-induced glial activation, CD40 expression, and NFкB-NLRP3 inflammatory signaling are reversed by DIZE. Furthermore, the beneficial effects of ACE2 activation, DIZE was found to be significantly blocked by MLN4760 (ACE2 inhibitor) as well as A779 (MasR antagonist) treatments. Hence, our study demonstrated that ACE2 activation reduced the platelet CD40-CD40L induced glial activation and neuroinflammation, hence imparted neuroprotection.

Identification and molecular mechanism of novel ACE inhibitory peptides from broccoli protein

Many natural angiotensin-converting enzyme inhibitory (ACEI) peptides have been widely studied and used to prevent and control hypertension. In this study, peptideomics and 3D-QSAR models combined with experimental verification were used to rapidly screen ACEI peptides in broccoli protein hydrolysates, followed by molecular docking and intracellular antihypertensive activity analysis. The results showed that two novel peptides FVLPLR and LPWYR were obtained, and their IC50 values for inhibiting ACE activity in vitro were 3.06 μM and 19.05 μM, respectively. Molecular docking results showed that FVLPLR and LPWYR bind to ACE through hydrogen bonding, electrostatic interaction, and hydrophobic interaction. Both peptides can promote HUVEC cells to produce vasodilator factor NO. These results indicated that broccoli protein could be used as an excellent source of ACE inhibitors.

YAP1-mediated dysregulation of ACE-ACE2 activity augments cardiac fibrosis upon induction of hyperglycemic stress

BackgroundDiabetic stress acts on the cardiac tissue to induce cardiac hypertrophy and fibrosis. Diabetes induced activated renin angiotensin system (RAS) has been reported to play a critical role in mediating cardiac hypertrophy and fibrosis. Angiotensin converting enzyme (ACE) in producing Angiotensin-II, promotes cardiomyocyte hypertrophy and fibrotic damage. ACE2, a recently discovered molecule structurally homologous to ACE, has been reported to be beneficial in reducing the effect of RAS driven pathologies. MethodsIn vivo diabetic mouse model was used and co-labelling immunostaining assay have been performed to analyse the fibrotic remodeling and involvement of associated target signaling molecules in mouse heart tissue. For in vitro analyses, qPCR and western blot experiments were performed in different groups for RNA and protein expression analyses. ResultsFibrosis markers were observed to be upregulated in the diabetic mouse heart tissue as well as in high glucose treated fibroblast and cardiomyocyte cells. Hyperglycemia induced overexpression of YAP1 leads to increased expression of β-catenin (CTNNB1) and ACE with downregulated ACE2 expression. The differential expression of ACE/ACE2 promotes TGFB1-SMAD2/3 pathway in the hyperglycemic cardiomyocyte and fibroblast resulting in increased cardiac fibrotic remodeling. ConclusionIn the following study, we have reported YAP1 modulates the RAS signaling pathway by inducing ACE and inhibiting ACE2 activity to augment cardiomyocyte hypertrophy and fibrosis in hyperglycemic condition. Furthermore, we have shown that hyperglycemia induced dysregulation of ACE-ACE2 activity by YAP1 promotes cardiac fibrosis through β-catenin/TGFB1 dependent pathway.

Egg white hydrolysate modulates the renin-angiotensin system in mesenteric perivascular adipose tissue in doca-salt hypertensive rats and restores its anticontractile ability

Perivascular adipose tissue (PVAT) regulates vascular tonus with an anticontractile effect, which may be dysfunctional in hypertension. An Egg White Hydrolysate (EWH), a bioactive food, restores endothelium dysfunction and reduces blood pressure levels in malignant hypertension. We aimed to evaluate whether dietary supplementation with EWH interferes with the PVAT function in the mesenteric resistance arteries (MRA) of DOCA-salt hypertensive animals and the mechanisms involved. Male rats were divided into 4 groups and treated for 8 weeks. For 4 weeks, DOCA-salt or vehicle-treated rats (SHAM) were induced, and after that, some rats were co-treated with DOCA-salt or vehicle plus EWH (1 g/kg/day) for 4 weeks more. MRA and/or their PVAT (mPVAT) were used for functional, molecular, and biochemical analysis. The anticontractile effect of mPVAT in response to norepinephrine (NE) was observed only in MRA rings with PVAT of the SHAM group, while this effect was abolished in DOCA-salt rings. The EWH treatment did not change the anticontractile effect of mPVAT in SHAM but partially restored it in DOCA-salt rats. Acute aliskiren incubation reduced NE-induced contraction only in MRA with PVAT of DOCA-salt rats. EWH prevented the overactivation of the renin levels and ACE activity in mPVAT of DOCA-salt rats; while did not change AT1R expression, but increased AT2R expression. In mPVAT, EWH blocked the increase of MDA, ROS and pro-inflammatory cytokines observed in DOCA-salt rats. EWH improved PVAT dysfunction in MRA of severe hypertension. This beneficial effect could be mediated by an ameliorated redox balance, inflammatory state, and RAS axis.

Catecholamine induces endothelial dysfunction via Angiotensin II and intermediate conductance calcium activated potassium channel

Endothelial dysfunction contributes to the pathogenesis of Takotsubo syndrome (TTS). However, the exact mechanism underlying endothelial dysfunction in the setting of TTS has not been completely clarified. This study aims to investigate the roles of angiotensin II (Ang II) and intermediate-conductance Ca2+-activated K+ (SK4) channels in catecholamine-induced endothelial dysfunction. Human cardiac microvascular endothelial cells (HCMECs) were exposed to 100 µM epinephrine (Epi), mimicking the setting of TTS. Epi treatment increased the ET-1 concentration and reduced NO levels in HCMECs. Importantly, the effects of Epi were found to be mitigated in the presence of Ang II receptor blockers. Furthermore, Ang II mimicked Epi effects on ET-1 and NO production. Additionally, Ang II inhibited tube formation and increased cell apoptosis. The effects of Ang II could be reversed by an SK4 activator NS309 and mimicked by an SK4 channel blocker TRAM-34. Ang II also inhibited the SK4 channel current (ISK4) without affecting its expression level. Ang II could depolarize the cell membrane potential. Ang II promoted ROS release and reduced protein kinase A (PKA) expression. A ROS blocker prevented Ang II effect on ISK4. The PKA activator Sp-8-Br-cAMPS increased SK4 channel currents. Epinephrine enhanced the activity of ACE by activating the α1 receptor/Gq/PKC signal pathway, thereby promoting the secretion of Ang II. The study suggested that high-level catecholamine can increase Ang II release from endothelial cells by α1 receptors/Gq/PKC signal pathway. Ang II can inhibit SK4 channel current by increasing ROS generation and reducing PKA expression, thereby contributing to endothelial dysfunction.

Chemical Compositions of Lianqiao (Forsythia suspensa) Extracts and Their Potential Health Benefits.

This study evaluated the fruits of Forsythia suspensa (Lianqiao), an important economic crop, for the chemical components of its water and ethanol extracts, inhibitory effects on SARS-CoV-2 virus spike protein binding to ACE2, inhibition of ACE2 activity, and capacity to scavenge free radicals. A total of 42 compounds were tentatively identified in the extracts via HPLC-MS/MS analysis. The water extract showed a greater ACE2 inhibition but a weaker inhibition on SARS-CoV-2 spike protein binding to ACE2 than the ethanol extract on a per-botanical-weight-concentration basis. The phenolic content was found to be greater in the water extract at 45.19 mg GAE/g dry botanical weight than in the ethanol extract (6.89 mg GAE/g dry botanical). Furthermore, the water extract had greater scavenging capacities against HO●, DPPH●, and ABTS●+ at 448.48, 66.36, and 121.29 µmol TE/g dry botanical, respectively, as compared to that of the ethanol extract (154.04, 3.55, and 33.83 µmol TE/g dry botanical, respectively). These results warrant further research into, and the development of, the potential COVID-19-preventive applications of Lianqiao and its extracts.

Potential of clove, cinnamon and honeysuckle in suppressing the SARS-CoV-2 spike protein-ACE2 binding, inhibiting ACE2 activity, and scavenging radicals

Water and ethanol extracts of clove (Syzygium aromaticum (L.) Merr. &amp; L.), cinnamon (Cinnamomum verum) and honeysuckle (Lonicerae japonicae) were examined for their chemical compositions, inhibition of SARS-CoV-2 spike protein-ACE2 binding, ACE2 inhibition, and free radical scavenging activity. UHPLC-MS/MS analysis tentatively identified 34, 36, and 27 compounds in clove, honeysuckle, and cinnamon water (WE) and ethanol extracts (EE), respectively. The extracts dose-dependently suppressed SARS-CoV-2 spike protein-ACE2 binding activity and ACE2 activity. Clove and cinnamon WEs at 33.3 mg dry botanical equivalents (BE)/mL, and cinnamon and honeysuckle EEs at 3.3 mg BE/mL showed almost 100% inhibition of S-protein-ACE2 binding activity. TPC values ranged from 5.3 mg GAE/g (honeysuckle EE) to 180.0 mg GAE/g (clove EE). The highest HO·, DPPH·, ABTS·+ scavenging activity were 2181 (clove EE), 536.91 (clove WE), and 3525.1 (clove WE) µmol TE/g respectively. These data suggested the potential of these botanicals in reducing the risk of SARS-CoV-2 infection and COVID-19 severe symptom development.