Angiotensin-converting Enzyme Enzyme Research Articles

Reduction in ACE2 expression in peripheral blood mononuclear cells during COVID-19 – implications for post COVID-19 conditions

BackgroundSevere COVID-19 is uncommon, restricted to 19% of the total population. In response to the first virus wave (alpha variant of SARS-CoV-2), we investigated whether a biomarker indicated severity of disease and, in particular, if variable expression of angiotensin converting enzyme 2 (ACE2) in blood might clarify this difference in risk and of post COVID -19 conditions (PCC).MethodsThe IRB-approved study compared patients hospitalized with severe COVID-19 to healthy controls. Severe infection was defined requiring oxygen or increased oxygen need from baseline at admission with positive COVID-19 PCR. A single blood sample was obtained from patients within a day of admission. ACE2 RNA expression in blood cells was measured by an RT-PCR assay. Plasma ACE1 and ACE2 enzyme activities were quantified by fluorescent peptides. Plasma TIMP-1, PIIINP and MMP-9 antigens were quantified by ELISA. Data were entered into REDCap and analyzed using STATA v 14 and GraphPad Prism v 10.ResultsForty-eight patients and 72 healthy controls were recruited during the pandemic. ACE2 RNA expression in peripheral blood mononuclear cells (PBMC) was rarely detected acutely during severe COVID-19 but common in controls (OR for undetected ACE2: 12.4 [95% CI: 2.62-76.1]). ACE2 RNA expression in PBMC did not determine plasma ACE1 and ACE2 activity, suggesting alternative cell-signaling pathways. Markers of fibrosis (TIMP-1 and PIIINP) and vasculopathy (MMP-9) were additionally elevated. ACE2 RNA expression during severe COVID-19 often responded within hours to convalescent plasma. Analogous to oncogenesis, we speculate that potent, persistent, cryptic processes following COVID-19 (the renin-angiotensin system (RAS), fibrosis and vasculopathy) initiate or promote post-COVID-19 conditions (PCC) in susceptible individuals.ConclusionsThis work elucidates biological and temporal plausibility for ACE2, TIMP1, PIIINP and MMP-9 in the pathogenesis of PCC. Intersection of these independent systems is uncommon and may in part explain the rarity of PCC.

Toxicity study and effect of protein hydrolysates derived from black tilapia (Oreochromis placidus) on hypertensive induced mice

Protein hydrolysates are specific protein fragments, produced during enzymatic hydrolysis and can exert various biological functions. The present study investigated the acute toxicity study of protein hydrolysates derived from black tilapia (Oreochromis placidus) and their effect on hypertensive-induced mice. Protein hydrolysates were produced from black tilapia protein isolate through enzymatic hydrolysis. A single dose of protein hydrolysates at 2000 mg/kg of body weight was administered and any changes were observed for 14 days. During 14 days, there were no significant changes in liver enzyme content and kidney function content, adverse clinical signs and mortality. The effect of the administration of protein hydrolysates in hypertensive-induced mice was studied. The body weight, blood pressure, full blood count {red blood cell (RBC), white blood cell (WBC) and platelets} were observed. Hypertensive mice (systolic blood pressure; 161±3 mm/Hg) were fed with pellet consisting of protein hydrolysates at different concentrations as well as carvedilol and combination of carvedilol and protein hydrolysates and systolic blood pressure was monitored. After 28 days, there was a significant reduction of blood pressure in the group of carvedilol (107±4 mm/Hg), 5% protein hydrolysate (119±1 mm/Hg), 10% protein hydrolysate (123±1 mm/Hg), 20% protein hydrolysate (115±2 mm/Hg) and 10% protein hydrolysate in combination with carvedilol (103±2 mm/Hg). Red blood cells significantly increased in hypertension mice but no significant changes in white blood cells and platelets after 28 days. Administration of protein hydrolysates reduced red blood cell levels similar to control group. A significant increase in body weight was observed in hypertension mice administered with protein hydrolysates at different concentrations as well as carvedilol and a combination of carvedilol and protein hydrolysates compared to control group and hypertensive group. Studies on any changes in liver enzyme level, kidney function level and angiotensin converting enzyme (ACE) activity on blood serum were carried out. Results showed that treatment with protein hydrolysates on hypertensive-induced mice reduced liver enzyme levels (ALP, ALT and GGT) and kidney function levels (Na+, K+ and Cl-) to normal levels. ACE enzyme activity of hypertensive-induced mice in the serum was also reduced similar to control mice after being treated with protein hydrolysates.

In-depth in silico and in vitro screening of selected edible plants for identification of selective C-domain ACE-1 inhibitor and its synergistic effect with captopril

Angiotensin converting enzyme (ACE) is a crucial enzyme in renin angiotensin aldosterone system (RAAS), having a pivotal role in blood pressure regulation. Despite its widespread medical applications in hypertension, heart diseases, diabetic nephropathy, and many others, inhibitors of the ACE enzyme suffer from different side effects that limit their use. Plants and natural products are the primary sources of renewable natural compounds that could act as potential leads for different ailments. The following study represents the identification of ACE inhibitors from carefully selected edible plants through adopting combined in silico techniques with biological testing. Molecular docking studies were performed on 1526 phytoconstituents present in 19 edible plants. Biochemical testing of extracts from the top ten hit plants revealed that Moringa oleifera is a potent ACE-1 inhibitor with an IC50 value of 104.4 μg/mL. On top of that, its isolated compound 4-O-caffeoylquinic acid had IC50 value of 62.92 μM. In silico combination analysis showed synergistic effects of moringa extract and 4-O-caffeoylquinic acid combined with captopril, especially at 90% effect level. This, in turn, is likely to reduce side effects and toxicity. Furthermore, selective domain docking showed strong affinity of 4-O-caffeoylquinic acid to the C-domain of ACE enzyme. Since the inflammatory responses and elevated reactive oxygen species in vasculature increase hypertension, the antioxidant effect of the compound was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and it possessed an acceptable effect with IC50 value of 73.82 μM. These findings advocate the antihypertensive potential of moringa leaves extract. Besides, we introduce 4-O-caffeoylquinic acid as a candidate lead for the design of safe, bidirectional ACE-1 inhibitor with strong antioxidant effect.

Enzyme-Based Antiviral Potential of Cinnamomum verum J. Presl. Essential Oil and Its Major Component (E)-Cinnamaldehyde.

In the present study, Cinnamomum verum J. Presl. bark essential oil and its main component cinnamaldehyde was evaluated in vitro for neuraminidase (NA), transmembrane serine protease (TMPRSS2), and angiotensin converting enzyme 2 (ACE2) inhibitory activities. The chemical composition of C. verum essential oil was confirmed by both gas chromatography-mass spectrometry (GC/MS), and gas chromatography-flame ionization detection (GC-FID), where 75.9% (E)-cinnamaldehyde was the major component. The ACE2, NA, and TMPRSS2 enzyme inhibitions of C. verum bark essential oil at 20 μg/mL concentration, and (E)-cinnamaldehyde (5 μg/mL) were calculated and compared in the range of 54.2-89.9%. Molecular docking results supported that (E)-cinnam-aldehyde was specific to ACE2 with 89.9% inhibition. Our findings suggest further in vivo studies to confirm the effective and safe use of the essential oil as well as the (E)-cinnamaldehyde.

A novel ACE2-Based electrochemical biosensor for sensitive detection of SARS-CoV-2

SARS-CoV-2 emerged in late 2019 and quickly spread globally, resulting in significant morbidity, mortality, and socio-economic disruptions. As of now, collaborative global efforts in vaccination and the advent of novel diagnostic tools have considerably curbed the spread and impact of the virus in many regions. Despite this progress, the demand remains for low-cost, accurate, rapid and scalable diagnostic tools to reduce the influence of SARS-CoV-2. Herein, the angiotensin-converting enzyme 2 (ACE2), a receptor for SARS-CoV-2, was immobilized on two types of electrodes, a screen-printed gold electrode (SPGE) and a screen-printed carbon electrode (SPCE), to develop electrochemical biosensors for detecting SARS-CoV-2 with high sensitivity and selectivity. This was achieved by using 1H, 1H, 2H, 2H-perfluorodecanethiol (PFDT) and aryl diazonium salt serving as linkers for SPGEs and SPCEs, respectively. Once SARS-CoV-2 was anchored onto the ACE2, the interaction of the virus with the redox probe was analyzed using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Aryl diazonium salt was observed as a superior linker compared to PFDT due to its consistent performance in the modification of the SPCEs and effective ACE2 enzyme immobilization. A distinct pair of redox peaks in the cyclic voltammogram of the biosensor modified with aryl diazonium salt highlighted the redox reaction between the functional groups of SARS-CoV-2 and the redox probe. The sensor presented a linear relationship between the redox response and the logarithm of SARS-CoV-2 concentration, with a detection limit of 1.02 × 106 TCID50/mL (50% tissue culture infectious dose). Furthermore, the biosensor showed remarkable selectivity towards SARS-CoV-2 over H1N1virus.

Angiotensin I and II Stimulate Cell Invasion of SARS-CoV-2: Potential Mechanism via Inhibition of ACE2 Arm of RAS.

Angiotensin-converting enzyme 2 (ACE2), one of the key enzymes of the renin-angiotensin system (RAS), plays an important role in SARS-CoV-2 infection by functioning as a virus receptor. Angiotensin peptides Ang I and Ang II, the substrates of ACE2, can modulate the binding of SARS-CoV-2 Spike protein to the ACE2 receptor. In the present work, we found that co incubation of HEK-ACE2 and Vero E6 cells with the SARS-CoV-2 Spike pseudovirus (PVP) resulted in stimulation of the virus entry at low and high micromolar concentrations of Ang I and Ang II, respectively. The potency of Ang I and Ang II stimulation of virus entry corresponds to their binding affinity to ACE2 catalytic pocket with 10 times higher efficiency of Ang II. The Ang II induced mild increase of PVP infectivity at 20 microM; while at 100 microM the increase (129.74+/-3.99 %) was highly significant (p<0.001). Since the angiotensin peptides act in HEK ACE2 cells without the involvement of angiotensin type I receptors, we hypothesize that there is a steric interaction between the catalytic pocket of the ACE2 enzyme and the SARS-CoV-2 S1 binding domain. Oversaturation of the ACE2 with their angiotensin substrate might result in increased binding and entry of the SARS-CoV-2. In addition, the analysis of angiotensin peptides metabolism showed decreased ACE2 and increased ACE activity upon SARS-CoV-2 action. These effects should be taken into consideration in COVID-19 patients suffering from comorbidities such as the over-activated renin-angiotensin system as a mechanism potentially influencing the SARS-CoV-2 invasion into recipient cells.

Evaluation of antihypertensive activity and molecular docking analysis of Padina boergesenii extract

IntroductionAntihypertensive drugs that are chemically synthesized usually tend to initiate different health complications. The quest for bioactive molecules to create novel medicines has focused on Marine resources like seaweeds. These molecules can furnish a positive probability for patients to gain benefits from these natural substances. MethodsThis study aims to identify phytoconstituents present in brown seaweed-Padina boergesenii. Five different solvents were used to prepare extracts and their antioxidant activity as well as antihypertensive activity was evaluated. Phytoconstituents were identified using LC-MS/MS, and subjected to molecular interaction against ACE enzyme. ResultsThe 70% ethanolic extract exhibited the highest total phenolic content (TPC), significant radical scavenging activity and concentration dependent Angiotensin Converting Enzyme (ACE) inhibition activity. LC-MS/MS analysis confirmed the presence of bioactive compounds from which 7,8 dihydroxycoumarin had the highest affinity against ACE enzyme in molecular docking study. ConclusionThese findings advocate that Padina boergesenii can be a potential source for developing novel antihypertensive therapeutic drug(s) and could pave the way for evolving effective and safe remedies from natural resources.

The role of angiotensin converting enzyme (insertion)/(deletion) and angiotensin II type 1 receptor (A1166C) gene polymorphisms in antiproteinuric effect of ACE inhibitors in type 2 diabetic Iraqi patients

The angiotensin converting enzyme (ACE) I\D gene polymorphism influences the blood ACE enzyme activity. Renoprotective effect of ACE inhibitors (ACEIs) varies among patients due to genetic variation, particularly in Renin-Angiotensin-Aldosterone System genes. This study investigates the genetic variations of ACE I\D and AGT1RA1166C gene polymorphisms in the antiproteinuric effect of ACEI therapy in type 2 diabetes mellitus (T2DM) patients. This is a cross-sectional study that included 76 T2DM patients who are ACEI users, divided into two groups: T2DM without diabetic kidney disease (DKD) included 31 patients, and T2DM with DKD included 45 patients. Urine samples were taken for measurement of urine albumin and creatinine, then calculation of albumin-creatinine ratio (ACR). Blood samples were taken for the measurement of serum parameters and also for the extraction of DNA for genetic evaluation of ACEI/D and AGT1RA1166C gene polymorphisms. The results reveal that T2DM patients carrying the ID genotype have significantly lower ACE1 levels compared to DD and II carriers (p = 0.012). When grouping patients according to the ACR, serum ACE1 and angiotensin-converting enzyme 2 (ACE2) levels were higher in DKD compared to normalbuminuric patients, with the only significant difference for ACE2. After subdividing according to ACE I\D genotypes, the ACE2 differences were only significant in DD genotype carriers (p = 0.049) between DKD and normalbuminuric groups. While for AGT1RA1166C polymorphisms, the AC genotype shows non-significantly lower levels for ACE1 and ACE2. After subdividing according to AGT1RA1166C genotypes, ACE2 levels were significantly higher in DKD patients carrying the AA genotype (p = 0.015). Binary logistic regression analysis revealed that both ACE (I\D) and AGT1RA1166C genes are significant predictors of ACE1 levels after controlling age, gender, and DKD state. This study concluded that both genes are predictors of ACE1 levels; in addition, ID genotype carriers and AC genotype carriers had lower ACE1 and ACE2 levels with lower ACR and higher glomerular filtration rate, identifying better ACEIs responses in ID and AC carriers.

In silico study of myomere muscle proteins extracted from Indian walking catfish reveal Angiotensin Converting Enzyme (ACE) inhibitory activity – A potential bioactive peptide

Clarias magur (Hamilton, 1822), is an endemic Asian freshwater catfish known as the walking catfish is one of the most popular fish in India and Asian subcontinents due to its nutritional value and better taste. The fish has traditionally been used for medicinal purposes. The present study was undertaken to study the proteome profile through Liquid Chromatography based Mass spectroscopy (LC/MS) to elucidate the protein profile the catfish. In the present study muscle protein extract was prepared from C. magur, digested by trypsin for LC/MS analysis for peptide retrieval. Out of a total of 468 peptides retrieved from LCMS data, 23 peptides showed bioactivity for Angiotensin Converting Enzyme (ACE) inhibition using bioinformatic approaches. ACE enzyme is expressed on the surface of lung cells and acts as a receptor for SARS-CoV-2 spike protein to gain entry into host cells. ACE inhibitors can have implication in entry of virus into host cells and reduction of hypertension by effectively reducing vasoconstriction. Traditionally synthetic compounds used for ACE inhibition pose side effects. Fish derived ACE inhibitory bioactive peptides can prove to be a natural, less toxic therapeutic sources.

Exploring the potential of chewing gums containing plant extracts (clove, saffron, and clove-mint) as a natural solution for controlling obesity and associated health issues

Background:Obesity is a global health concern resulting from an excessive accumulation of fat in the body, affecting individuals of all ages, including children. Modern lifestyles and the consumption of high-calorie foods have resulted in an increase in obesity prevalence. Cardiovascular disease, diabetes, blood pressure, and certain cancers are all serious health problems that obesity can lead to.Objectives: Medicinal properties in functional foods are gaining popularity in the food industry for controlling or inhibiting diseases. Given the growing concerns about obesity and its associated health risks, the need for natural compounds with controlling or inhibiting properties is paramount. This study aimed to explore natural plant extracts for their functional properties, particularly their ability to control obesity by inhibiting lipase enzyme. To transport these biological compounds, chewing gums containing extracts of cloves (at concentrations of 0.1%, 1%, and 3%), saffron, and mint were developed. Chewing gums containing extracts can become a popular natural remedy for a variety of health problems, including obesity. Using an effective delivery system, this solution is widely available to those looking for natural alternatives to address their health concerns.Methods: The research centered on exploring the properties of natural plant extracts, which included their potential to inhibit enzymes linked to obesity and related diseases, their antioxidant properties to counteract the harmful effects of body fat oxidation, and their antibacterial properties. In addition, the research involved a sensory evaluation of chewing gum that contained these extracts.Results: Clove extract had the highest amounts of total phenolic compounds. Also, clove extract exhibited the highest antioxidant properties and Helicobacter pylori inhibition (88.05% and 25.69% at ratio of 0.7% respectively), which is thought to be associated with its high content of eugenol and other phenolic compounds. Furthermore, the extracts were evaluated for other functional properties, including their ability to inhibit pancreatic lipase, angiotensin converting enzyme (ACE), and microbial activities against Streptococcus faecalis and Candida albicans. Among extracts, saffron extract showed the highest lipase inhibitory properties (40.07, and 36.06% at concentrations of 0.7% and 0.5% respectively). Also, clove and mint showed pancreatic lipase inhibition about 31.50% and 29.24 % at concentration of 0.7 and 0.5% respectively, revealing that all extracts can be a good candidate to be used as effective additives in preventing and controlling obesity. Also, clove, mint, and saffron extracts could inhibit blood pressure enzymes (25.54, 20.70, and 19.61 respectively), which can help maintain healthy blood pressure levels. Furthermore, release kinetics of extracts from chewing gums were obtained, and shown that after 20 min the release of extracts were 73.24, 64.34, and 63.2 for saffron, mint, and clove (1%) respectively.Conclusions: Extracts were found in our research to have a beneficial effect on controlling obesity. These compounds may be effective in preventing obesity, based on their observed inhibition of pancreatic lipase enzyme. However, further research is necessary to fully comprehend the efficacy of these substances for this purpose. The significant antioxidant properties of clove may have a promising impact on reducing free radicals, which can help prevent fat oxidation in the bodies of individuals with obesity. The inhibition of ACE enzyme by extracts could potentially have a positive impact on controlling blood pressure. The extracts showed potent antimicrobial properties that can potentially alleviate mouth and throat issues associated with Streptococcus bacteria. Moreover, extracts demonstrated efficacy in reducing the presence of H. pylori, which is the causative agent of stomach infections. Also, it was shown that chewing gum can be a convenient and easily accessible means of delivering natural compounds and may be a desirable option for individuals seeking natural alternatives for managing their health concerns.Keywords: Chewing gum, Plant extracts, Obesity, Blood pressure, H. pylori infections

Exploring the potential of chewing gums containing plant extracts (clove, saffron, and clove-mint) as a natural solution for controlling obesity and associated health issues

Background:Obesity is a global health concern resulting from an excessive accumulation of fat in the body, affecting individuals of all ages, including children. Modern lifestyles and the consumption of high-calorie foods have resulted in an increase in obesity prevalence. Cardiovascular disease, diabetes, blood pressure, and certain cancers are all serious health problems that obesity can lead to.Objectives: Medicinal properties in functional foods are gaining popularity in the food industry for controlling or inhibiting diseases. Given the growing concerns about obesity and its associated health risks, the need for natural compounds with controlling or inhibiting properties is paramount. This study aimed to explore natural plant extracts for their functional properties, particularly their ability to control obesity by inhibiting lipase enzyme. To transport these biological compounds, chewing gums containing extracts of cloves (at concentrations of 0.1%, 1%, and 3%), saffron, and mint were developed. Chewing gums containing extracts can become a popular natural remedy for a variety of health problems, including obesity. Using an effective delivery system, this solution is widely available to those looking for natural alternatives to address their health concerns.Methods: The research centered on exploring the properties of natural plant extracts, which included their potential to inhibit enzymes linked to obesity and related diseases, their antioxidant properties to counteract the harmful effects of body fat oxidation, and their antibacterial properties. In addition, the research involved a sensory evaluation of chewing gum that contained these extracts.Results: Clove extract had the highest amounts of total phenolic compounds. Also, clove extract exhibited the highest antioxidant properties and Helicobacter pylori inhibition (88.05% and 25.69% at ratio of 0.7% respectively), which is thought to be associated with its high content of eugenol and other phenolic compounds. Furthermore, the extracts were evaluated for other functional properties, including their ability to inhibit pancreatic lipase, angiotensin converting enzyme (ACE), and microbial activities against Streptococcus faecalis and Candida albicans. Among extracts, saffron extract showed the highest lipase inhibitory properties (40.07, and 36.06% at concentrations of 0.7% and 0.5% respectively). Also, clove and mint showed pancreatic lipase inhibition about 31.50% and 29.24 % at concentration of 0.7 and 0.5% respectively, revealing that all extracts can be a good candidate to be used as effective additives in preventing and controlling obesity. Also, clove, mint, and saffron extracts could inhibit blood pressure enzymes (25.54, 20.70, and 19.61 respectively), which can help maintain healthy blood pressure levels. Furthermore, release kinetics of extracts from chewing gums were obtained, and shown that after 20 min the release of extracts were 73.24, 64.34, and 63.2 for saffron, mint, and clove (1%) respectively.Conclusions: Extracts were found in our research to have a beneficial effect on controlling obesity. These compounds may be effective in preventing obesity, based on their observed inhibition of pancreatic lipase enzyme. However, further research is necessary to fully comprehend the efficacy of these substances for this purpose. The significant antioxidant properties of clove may have a promising impact on reducing free radicals, which can help prevent fat oxidation in the bodies of individuals with obesity. The inhibition of ACE enzyme by extracts could potentially have a positive impact on controlling blood pressure. The extracts showed potent antimicrobial properties that can potentially alleviate mouth and throat issues associated with Streptococcus bacteria. Moreover, extracts demonstrated efficacy in reducing the presence of H. pylori, which is the causative agent of stomach infections. Also, it was shown that chewing gum can be a convenient and easily accessible means of delivering natural compounds and may be a desirable option for individuals seeking natural alternatives for managing their health concerns.Keywords: Chewing gum, Plant extracts, Obesity, Blood pressure, H. pylori infections

The possible effects of COVID-19 on the human reproductive system

Spike surface glycoprotein and small envelope matrix-nucleocapsid proteins, is from the Coronaviridae family and binds to host receptors via spike surface proteins. Although it shows its symptoms especially on the respiratory tract, various studies have been carried out considering that it also affects other systems in the body. For the virus to enter the host cell, it must bind to ACE2 (angiotensin converting enzyme 2). ACE2 is a key protein involved in balancing Ang I and Ang II levels. With receptors such as TMPRSS2 (transmembrane serine protease 2), the effects of the virus on the human reproductive system are much better understood. Since human germ cells and early embryos express ACE2, there is a potential risk of the Coronavirus associated with germ cells. Studies show that the coronavirus changes the amount and density of hormones in the human reproductive system. The fact that most of the partners of 35 female patients who had SARS-CoV-2 in the studies were infected individuals suggests that sexual transmission may be possible. It was determined that TMPRSS4, Cathepsin B and L, FURIN, MX1 and BSG gene expressions were high in the menstrual cycle, while ACE 2 and TMPRSS2 were moderately expressed. It has been shown that the ACE2 enzyme is most intensely expressed is the testes. Studies have shown that sperm DNA (deoxyribonucleic acid) fragmentation, changes in hormone levels and the formation of anti-sperm antibodies are an important cause of male infertility. Infected men have been found to have an impaired spermatogenesis. This rewiew; it aims to draw attention to the possible effects of the corona virus on the human reproductive system and to reveal new mechanisms for new research to be done.

Conformational perturbation of SARS-CoV-2 spike protein using N-acetyl cysteine: an exploration of probable mechanism of action to combat COVID-19

The infection caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) resulted in a pandemic with huge death toll and economic consequences. The virus attaches itself to the human epithelial cells through noncovalent bonding of its spike protein with the angiotensin-converting enzyme-2 (ACE2) receptor on the host cell. Based on in silico studies we hypothesized that perturbing the functionally active conformation of spike protein through the reduction of its solvent accessible disulfide bonds, thereby disintegrating its structural architecture, may be a feasible strategy to prevent infection by reducing the binding affinity towards ACE2 enzyme. Proteomics data showed that N-acetyl cysteine (NAC), an antioxidant and mucolytic agent been widely in use in clinical medicine, forms covalent conjugates with solvent accessible cysteine residues of spike protein that were disulfide bonded in the native state. Further, in silico analysis indicated that the presence of the selective covalent conjugation of NAC with Cys525 perturbed the stereo specific orientations of the interacting key residues of spike protein that resulted in threefold weakening in the binding affinity of spike protein with ACE2 receptor. Interestingly, almost all SARS-CoV-2 variants conserved cystine residues in the spike protein. Our finding results possibly provides a molecular basis for identifying NAC and/or its analogues for targeting Cys-525 of the viral spike protein as fusion inhibitor and exploring in vivo pharmaco-preventive and its therapeutic potential activity for COVID-19 disease. However, in-vitro assay and animal model-based experiment are required to validate the probable mechanism of action. Communicated by Ramaswamy H. Sarma

Roles of glycosylation and redox states on SARS-CoV-2 spike protein actions

Abstract The pandemic of Coronavirus Disease 2019 (COVID-19) is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The viral fusion protein, spike protein, binds to its receptor Angiotensin-Converting Enzyme 2 (ACE2) to enter host cells. Further, the S1 subunit of the spike protein may be cleaved off the virus and affect various organs. In addition to tightly binding to ACE2, S1 spike protein also enhances the peptidase activity of ACE2 and activate cell signaling. The present study compared effects of recombinant S1 spike proteins expressed in HEK cells and in E. coli. The spike protein expressed in HEK cells is heavily glycosylated and binds strongly to ACE2, while the protein expressed in E. coli is not glycosylated and exhibits no ACE2 binding. The SulfoBiotics Protein Redox State Monitoring assay determined that cysteine residues of the spike protein expressed in HEK cells are fully oxidized, while those of the protein expressed in E. coli are reduced. The deglycosylation of the protein expressed in HEK cells by Glycopeptidase F attenuates the ACE2 binding, although not completely, and the oxidation of the E. coli protein by hydrogen peroxide enhances the binding. In contrast to the highly distinct ACE2 binding capacities of spike proteins expressed in HEK cells and in E coli, spike proteins expressed in both systems enhance the ACE2 peptidase activity and promote cell signaling. These results suggest that the glycosylated state contributes to the binding of the spike protein to ACE2 and introduce a new concept of the regulation of the spike protein-ACE2 binding by redox mechanisms. Glycosylation and redox states, however, do not define the abilities of the spike protein to enhance the ACE2 enzyme activity or promote cell signaling. Supported by grants from NIH (R03 AG71596, R21 AG73919)

Angiotensin-Converting Enzyme Inhibition Properties and Antioxidant Effects of Plants and their Bioactive Compounds as Cardioprotective Agent

Background: The prevalence of cardiovascular diseases is being increased; researchers are trying to explore effective preventive and treatment options. Antioxidant effects and AngiotensinConverting Enzyme (ACE) inhibitors demonstrated cardioprotective effects. Many herbs and plants have shown antiinflammatory, antioxidant, free radical scavenging, and ACE inhibition properties in preventing and treating cardiac-related disorders. Therefore, the exploration of bioactive compounds such as polyphenols, flavonoids, quercetin, kaempferol, isoflavones, and catechin needs to be explored as potential ACE inhibitors and antioxidants in preventing and treating cardiac-related diseases Objective: The present study is designed to investigate the cardio-protective potential of important bioactive compounds from plants and herbs. Methods: Articles were collected from electronic databases, such as PubMed, Google Scholar, Web of Science, and Science Direct, using the keywords antioxidant, anti-inflammatory, ACE inhibition and antihypertensive properties of plants and herbs. In vitro and in vivo studies on animal models have been included in the current study. Articles published in languages other than the English language were excluded, and finally, 100 manuscripts were included in this study. Results: Plants and herbs chosen for this study with abundant natural bioactive compounds have demonstrated ACE inhibition, antioxidant, anti-inflammatory, and anti-hypertensive properties and can be an effective cardioprotective. Hence, it could pave the way for the development of new therapeutics that could be beneficial in treating cardiovascular diseases Conclusion: The current review focuses on herbs and plants possessing ACE inhibition, antioxidant, antioxidative, anti-inflammatory, hyperaccumulating and anti-hypertensive properties with their ability to prevent the breakdown of ACE I enzyme into ACE enzyme II, acting as ACE inhibitors and showing its strong potential as a cardioprotective agent. Also, it could support the development of new therapeutic agents to address cardiovascular problems.

Investigating a Variant in the ACE Gene in Ahvaz Male and Female Athletes Compared to the Control Group with Normal Body Mass

Background: The ACE (angiotensin-converting enzyme) gene is located on chromosome 17 and encodes a metallopeptidase dependent on zinc (Zn) and is widely found on the surface of endothelial and epithelial cells. Objectives: This study compares the relationship between ACE enzyme activity and I/D genotype in male and female bodybuilders and normal aerobic male and female athletes. Methods: For this purpose, the blood of 200 people, who were divided into two groups of athletes with body mass and normal people, was collected and extracted, and the genotype distribution and allele frequency in both groups were checked by the PCR method. The data obtained from examining the D/I variant in the ACE gene in Ahvaz male and female athletes compared to the control group with normal body mass was evaluated using the chi-square test and GraphPad Prism 6 software. Results: Findings of the study showed that 28% of athletes had the D/D genotype, 24% had the I/D genotype, and 48% had the I/I genotype. The normal allele frequency distribution in the athlete population was 40% D allele and 60% I allele. Normal people had 42% D/D genotype, 29% I/D genotype, and 29% I/I genotype. Normal distribution in the control group was 57% D allele and 43% I allele. Conclusions: Findings of the study showed a higher chance of strength and sports ability in people with the I/I genotype. It seems that the activity of ACE among this genotype indicated an increase in activity in the I/I group compared to all the samples selected in the athlete group. The I/D genotype is associated with an increase in physical strength and also increases the activity of ACE, and there is a significant relationship between the activity of ACE compared to athletes and the control group.

Immune Response and Molecular Mechanisms of Cardiovascular Adverse Effects of Spike Proteins from SARS-CoV-2 and mRNA Vaccines.

The SARS-CoV-2 (severe acute respiratory syndrome coronavirus responsible for the COVID-19 disease) uses the Spike proteins of its envelope for infecting target cells expressing on the membrane the angiotensin converting enzyme 2 (ACE2) enzyme that acts as a receptor. To control the pandemic, genetically engineered vaccines have been designed for inducing neutralizing antibodies against the Spike proteins. These vaccines do not act like traditional protein-based vaccines, as they deliver the message in the form of mRNA or DNA to host cells that then produce and expose the Spike protein on the membrane (from which it can be shed in soluble form) to alert the immune system. Mass vaccination has brought to light various adverse effects associated with these genetically based vaccines, mainly affecting the circulatory and cardiovascular system. ACE2 is present as membrane-bound on several cell types, including the mucosa of the upper respiratory and of the gastrointestinal tracts, the endothelium, the platelets, and in soluble form in the plasma. The ACE2 enzyme converts the vasoconstrictor angiotensin II into peptides with vasodilator properties. Here we review the pathways for immunization and the molecular mechanisms through which the Spike protein, either from SARS-CoV-2 or encoded by the mRNA-based vaccines, interferes with the Renin-Angiotensin-System governed by ACE2, thus altering the homeostasis of the circulation and of the cardiovascular system. Understanding the molecular interactions of the Spike protein with ACE2 and the consequent impact on cardiovascular system homeostasis will direct the diagnosis and therapy of the vaccine-related adverse effects and provide information for development of a personalized vaccination that considers pathophysiological conditions predisposing to such adverse events.

Potential role of angiotensin converting enzyme/neprilysin pathway and protective effects of omapatrilat for paracetamol‑induced acute liver injury.

The renin-angiotensin-aldosterone system (RAAS) is an important pathway that contributes to the pathophysiology of acute liver injury due to paracetamol toxicity. Omapatrilat, a RAAS-acting agent, inhibits both angiotensin converting enzyme (ACE) and neprilysin/neutral endopeptidase (NEP). The aim of the present study was to investigate the hepatoprotective effects of omapatrilat and examine the role of ACE/NEP pathway on the physiopathology of paracetamol toxicity. A total of 56 BALB/c mice were separated into seven groups: Control, 40 mg/kg omapatrilat only, 400 mg/kg paracetamol only, paracetamol and 140 mg/kg N-acetylcysteine and three groups with paracetamol and 10-40 mg/kg omapatrilat. Blood and liver tissue samples were studied through histopathological imaging, alanine transaminase (ALT) and aspartate transaminase (AST) liver function tests and oxidant/antioxidant biomarker measurements including superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA). ACE and NEP activities were also measured. Histopathological analysis revealed that paracetamol toxicity resulted in a number of apoptotic and necrotic cells in liver tissue samples. By contrast, with 40 mg/kg omapatrilat administration in toxicity-induced mice, hepatocytes were significantly improved and exhibited similar appearance to the control group. Biochemical measurements also supported these histopathological results. Omapatrilat pretreatment provided a dose-dependent reduction in oxidative stress and reversed paracetamol toxicity indications by reducing ALT and AST activities, increasing SOD activity and GSH levels and reducing MDA levels. Dose-dependent increase of ACE and NEP enzymes in omapatrilat groups was also observed. The results demonstrated promotion of antioxidant activity by omapatrilat and suppression of oxidative stress associated with acute liver injury. These findings revealed the potential role of ACE/NEP pathway in paracetamol toxicity and hepatoprotective effects of omapatrilat against oxidative stress.

ACE2 and LOX Enzyme Inhibitions of Different Lavender Essential Oils and Major Components Linalool and Camphor.

In this present study, Lavandula angustifolia, Lavandula stoechas, and Lavandula × heterophylla essential oils and their main compounds linalool and camphor were evaluated in vitro for lipoxygenase enzyme (LOX) and for angiotensin converting enzyme 2 (ACE2) inhibition potential. The chemical compositions of L. angustifolia, L. stoechas, and L. heterophylla essential oils were confirmed both by gas chromatography–mass spectrometry and gas chromatography–flame ionization detection, where 22.4, 0.9, and 30.6% linalool and 17.8, 54.7, and 15% camphor were identified for each oil among other components, respectively. Enzyme inhibitory activity studies were performed at 20 μg/mL for the tested essential oils, whereas for linalool and camphor concentrations, 5 μg/mL was used. The ACE2 inhibitions of L. angustifolia, L. stoechas, and L. heterophylla essential oils were 25.4, 34.1, and 27.1%, while the LOX inhibitions were observed as 79, 49.1, and 86.7%, respectively. In addition, linalool and camphor showed remarkable ACE2 inhibition with 77.1 and 85.1%, whereas the LOX inhibition was observed at 92 and 67.2%, respectively. In conclusion of the initial findings, further detailed in vivo studies are needed to confirm the safe use.

Mitigation of Multi-Organ Radiation Injury with ACE2 Agonist Diminazene Aceturate.

The renin-angiotensin system (RAS) is known to regulate the pathogenesis of radiation-induced injury as inhibitors of the RAS enzyme angiotensin converting enzyme (ACE) have established function as mitigators of multi-organ radiation injury. To further elucidate the role of RAS signaling during both the acute and delayed syndromes of radiation exposure, we have evaluated whether pharmacologic modulation of alternate RAS enzyme angiotensin converting enzyme 2 (ACE2) reduces the pathogenesis of multi-organ radiation-induced injuries. Here, we demonstrate pharmacologic ACE2 activation with the small molecule ACE2 agonist diminazene aceturate (DIZE) improves survival in rat models of both hematologic acute radiation syndrome (H-ARS) and multi-organ delayed effects of acute radiation exposure (DEARE). In the H-ARS model, DIZE treatment increased 30-day survival by 30% compared to vehicle control rats after a LD50/30 total-body irradiation (TBI) dose of 7.75 Gy. In the mitigation of DEARE, ACE2 agonism with DIZE increased median survival by 30 days, reduced breathing rate, and reduced blood urea nitrogen (BUN) levels compared to control rats after partial-body irradiation (PBI) of 13.5 Gy. DIZE treatment was observed to have systemic effects which may explain the multi-organ benefits observed including mobilization of hematopoietic progenitors to the circulation and a reduction in plasma TGF-beta levels. These data suggest the ACE2 enzyme plays a critical role in the RAS-mediated pathogenesis of radiation injury and may be a potential therapeutic target for the development of medical countermeasures for acute radiation exposure.