Angiotensin-converting Enzyme 2 Protein Research Articles

The metalloproteinase ADAM10 sheds angiotensin-converting enzyme (ACE) from the pulmonary endothelium as a soluble, functionally active convertase.

The renin-angiotensin-aldosterone system (RAAS) plays a critical role in the regulation of blood pressure and fluid balance, with angiotensin-converting enzyme (ACE) being a key transmembrane enzyme that converts angiotensin I to angiotensin II. Hence, ACE activity is an important drug target in cardiovascular pathologies such as hypertension. Our study demonstrates that human pulmonary microvascular endothelial cells (HPMECs) are an important source of proteolytically released ACE. The proteolytic release of transmembrane proteins, a process known as ectodomain shedding, is facilitated by membrane proteases called sheddases. By knockout and inhibition studies, we identified ADAM10 (A disintegrin and metalloprotease 10) as a primary sheddase responsible for ACE release in HEK293 cells. The function of ADAM10 as primary, constitutive sheddase of ACE was confirmed in HPMECs. Moreover, we demonstrated the physiological relevance of ADAM10 for ACE shedding in exvivo precision cut lung slices (PCLS) from human and mouse lungs. Notably, ADAM17 activity is not directly involved in ACE shedding but indirectly by regulating ACE mRNA and protein levels, leading to increased ADAM10-mediated ACE shedding. Importantly, soluble ACE generated by shedding is enzymatically active and can thereby participate in systemic RAAS functions. Taken together, our findings highlight the critical role of ADAM10 (directly) and ADAM17 (indirectly) in ACE shedding and RAAS modulation.

High fat, high sucrose diet promotes increased expression of ACE2 receptor in the SIV-infected host: implications for SARS-CoV-2 infection.

People with pre-existing conditions, including metabolic comorbidities, are at greater risk for complications of SARS-CoV-2 infection and expression of machinery required for viral entry into host cells may be a contributing factor. This study tested the hypothesis that high fat, high sucrose diet (HFSD) and alcohol use increase expression of angiotensin converting enzyme 2 (ACE2) receptor and transmembrane serine protease 2 (TMPRSS2) in tissues isolated from simian immunodeficiency virus (SIV) infected macaques, the most clinically relevant model for the study of HIV. Biospecimens obtained from a longitudinal study of SIV-infected, antiretroviral therapy (ART)-treated female rhesus macaques (Macaca mulatta) were used to determine whether HFSD and chronic binge alcohol (CBA) increased ACE2 and TMPRSS2 protein and gene expression. Macaques (n = 10) were assigned to HFSD or standard diet (SD) for 3 months before CBA or vehicle administration. Three months later, macaques were infected with SIV; ART was initiated 2.5 months thereafter. Tissue samples including lung, pancreas, and kidney were collected at study endpoint (12 months post-SIV infection). Protein expression of ACE2 in the lung, whole pancreas, and pancreatic islets was significantly greater in HFSD- than SD-fed macaques with no significant differences in protein expression of TMPRSS2 or mRNA expression of ACE2 or TMPRSS2. CBA did not significantly alter any measures. The increased ACE2 receptor expression observed in lung and pancreas of SIV-infected HFSD-fed female rhesus macaques aligns with reports that diet may increase susceptibility to COVID-19. These data provide direct evidence for a link between dietary quality and cellular adaptations that may increase the risk for SARS-CoV-2 infection.

ACE2 Alleviates Endoplasmic Reticulum Stress and Protects against Pyroptosis by Regulating Ang1-7/Mas in Ventilator-Induced Lung Injury

Background: Ventilator-induced lung injury (VILI) is a consequence of inflammation and increased alveolar-capillary membrane permeability due to alveolar hyperdistention or elevated intrapulmonary pressure, but the precise mechanisms remain unclear. The aim of the study was to analyze the mechanism by which angiotensin converting enzyme 2 (ACE2) alleviates endoplasmic reticulum stress (ERS) and protects alveolar cells from pyroptosis in VILI by regulating angiotensin (Ang)1-7/Mas. Methods: VILI was induced in mice by mechanical ventilation by regulating the tidal volume. The alveolar cell line, A549, mimics VILI in vitro by cyclic stretch (CS). Ang (1-7) (100 nmol/L) was added to the medium. ERS was induced in cells by stimulating with tunicamycin (TM, 2 μg/mL). ERS was inhibited by tracheal instillation of 4-phenylbutyric acid (4-PBA) (1 mg/kg). ACE2's enzymatic function was activated or inhibited by subcutaneous injection of resorcinolnaphthalein (RES, 20 μg/kg) or MLN-4760 (20 μg/kg). pGLV-EF1a-GFP-ACE2 was instilled into the trachea to increase the protein expression of ACE2. The Ang (1-7) receptor, Mas, was antagonized by injecting A779 subcutaneously (80 μg/kg). Results: ACE2 protein levels decreased after modeling. Ang (1-7) level was decreased and Ang II was accumulated. ERS was significantly induced in VILI mice, and pyroptosis was observed in cells. When ERS was inhibited, pyroptosis under the VILI condition was significantly inhibited. Ang (1-7) alleviated ERS and pyroptosis under CS. When ERS was continuously activated, the function of Ang (1-7) in inhibiting pyroptosis was blocked. Resorcinolnaphthalein (RES) effectively promoted Ang II conversion, alleviated the Ang (1-7) level in VILI, ameliorated lung injury, and inhibited ERS and cell pyroptosis. Inhibiting ACE2's function in VILI hindered the production of Ang (1-7), promoted the accumulation of Ang II, and exacerbated ERS and pyroptosis, along with lung injury. The Mas antagonist significantly blocked the inhibitory effects of ACE2 on ERS and pyroptosis in VILI. Conclusions: Reduced ACE2 expression in VILI is involved in ERS and pyroptosis-related injury. ACE2 can alleviate ERS in alveolar cells by catalyzing the production of Ang (1-7), thus inhibiting pyroptosis in VILI.

COVID-19 and Pulmonary Embolism: A Comprehensive Review of Epidemiology, Pathophysiology, and Management

Global public health has suffered greatly as a result of the coronavirus illness 2019 (Covid-19) pandemic; yet when vaccinations against Covid-19 are available, they have contributed to the containment of the spread of SARS Coronavirus 2 (SARS-CoV-2) infection. However, there have been isolated reports of vaccine-induced cerebral venous sinus thrombosis (CVST) and vaccine-induced immune thrombotic thrombocytopenia (VITT) following viral vector vaccinations (Ad26.COV2 vaccine, AdOx1 nCoV-19 vaccine).One of the most effective ways to address the global health issue as the new SARS-CoV-2 virus spreads around the world is immunization against COVID-19.This condition manifests as thrombocytopenia, the formation of an autoantibody against platelet-factor 4,and widespread thrombosis in unusual places, mainly in the cerebral venous. (PF4). The human Freia receptor on platelets can be bound by the PF4 autoantibody, which can then cause the platelets to aggregate. This is an uncommon side effect that closely mimics the clinical presentation of the traditional immune-mediated HIT illness that develops after heparin exposure. We will talk about the recently reported side effect known as vaccine-induced immune thrombotic thrombocytopenia (VITT),which can happen after receiving specific COVID-19 vaccinations, in this Spotlight. Since the vaccinations have been employed, questions have been raised about their safety. Following the COVID-19 vaccine, the most frequent side effects include local reactions at the injection site and general systemic symptoms like fever, headache, weariness, and myalgia. These side effects could appear shortly after immunization and go away quickly. Nonetheless, a few uncommon cases of vaccine-induced immune thrombotic thrombocytopenia (VITT) have been documented, mostly in relation to vaccinations utilizing viral vectors. Platelet expression of spike protein and subsequent immune response, platelet expression of other adenoviral proteins and subsequent reactions, the role of antibodies against platelet factor 4 (PF4), the direct interaction between adenoviral vector and platelets, the cross-reactivity of antibodies against SARS-CoV-2 spike protein with PF4, the cross-reactivity of anti-adenovirus antibodies and PF4 interaction between spike protein and platelets. Because severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can activate platelets, thrombocytopenia while rare in the first presentation may also be an indicator of the severity of the disease. The spike protein-angiotensin converting enzyme 2 (ACE2) connection causes this directly, and the activation of coagulation and inflammation causes it indirectly. In COVID-19, dysregulation of the innate and adaptive immune systems is a significant contributing factor to thrombosis and thrombocytopenia.

Altered kidney distribution and loss of ACE2 into the urine in acute kidney injury.

There are diverse pathophysiological mechanisms involved in acute kidney injury (AKI). Among them, overactivity of the renin-angiotensin system (RAS) has been described. Angiotensin-converting enzyme 2 (ACE2) is a tissue RAS enzyme expressed in the apical border of proximal tubules. Given the important role of ACE2 in the metabolism of angiotensin II, this study aimed to characterize kidney and urinary ACE2 in a mouse model of AKI. Ischemia-reperfusion injury (IRI) was induced in C57BL/6 mice by clamping of the left renal artery followed by removal of the right kidney. In kidneys harvested 48 h after IRI, immunostaining revealed a striking maldistribution of ACE2 including spillage into the tubular lumen and the presence of ACE2-positive luminal casts in the medulla. In cortical membranes, ACE2 protein and enzymatic activity were both markedly reduced (37 ± 4 vs. 100 ± 6 ACE2/β-actin, P = 0.0004, and 96 ± 14 vs. 152 ± 6 RFU/μg protein/h, P = 0.006). In urine, full-length membrane-bound ACE2 protein (100 kDa) was markedly increased (1,120 ± 405 vs. 100 ± 46 ACE2/µg creatinine, P = 0.04), and casts stained for ACE2 were recovered in the urine sediment. In conclusion, in AKI caused by IRI, there is a marked loss of ACE2 from the apical tubular border with deposition of ACE2-positive material in the medulla and increased urinary excretion of full-length membrane-bound ACE2 protein. The deficiency of tubular ACE2 in AKI suggests that provision of this enzyme could have therapeutic applications and that its excretion in the urine may also serve as a diagnostic marker of severe proximal tubular injury.NEW & NOTEWORTHY This study provides novel insights into the distribution of kidney ACE2 in a model of AKI by IRI showing a striking detachment of apical ACE2 from proximal tubules and its loss in urine and urine sediment. The observed deficiency of kidney ACE2 protein and enzymatic activity in severe AKI suggests that administration of forms of this enzyme may mitigate AKI and that urinary ACE2 may serve as a potential biomarker for tubular injury.

Abstract 73: Extracellular vesicles-derived miR-125b-5p/miR-125a-5p promotes hypertension by regulating angiotensin-converting enzyme 2

Therapeutic targeting of non-coding RNAs, particularly microRNA (miRNA), presents an appealing approach in the treatment of chronic diseases such as resistant hypertension. Recently, miRNA have emerged as promising targets for therapeutic intervention, capable of regulating critical genes to provide a suitable solution to the lack of efficacy of current treatments. Our comprehensive miRNA profiling of plasma extracellular vesicles (EV) from DOCA-salt hypertensive mice of both sexes, compared to sham controls, identified two miRNA implicated in salt-sensitive hypertension, namely miR-125b-5p and miR-125a-5p. Our bioinformatic analysis suggests that these miRNA could be involved in angiotensin-converting enzyme 2 (ACE2) downregulation in hypertension. The present study intended to validate ACE2 as a target of miR-125. Quantitative RT-PCR and capillary western analysis of hypothalami from C57BL/6J DOCA+Salt hypertensive male and female mice following 3-weeks of DOCA+Salt treatment (n=5-6 per group, 3-month old), detected a significant decrease in ACE2 mRNA (males: 0.34±0.03 vs. 1.02±0.02; females: 0.65±0.08 vs. 1.01±0.01; P<0.05) and protein (males: 0.17±0.02 vs. 0.31±0.05; females: 0.16±0.03 vs. 0.37±0.07; P<0.05) expression for both sexes. Further investigation in bEND.3 cells treated with different concentrations of Ang-II (0, 10, 100 nM) for 12, 24, and 48 hours, demonstrated a dose-dependent negative correlation between miR-125b-5p (r≈-0.9978) or miR-125a-5p (r≈-1.002) and ACE2 gene expression, independently of time. When treated with miR-125 mimics the cells demonstrated a consistent downregulation of ACE2 protein levels (miR-125b-5p: 0.6±0.1 and miR-125a-5p: 2.0±0.2 vs. control: 2.8±0.3). Conversely, no significant change in ACE2 protein levels was observed with the respective miRNA inhibitors. Using a firefly/Renilla luciferase assay, we further identified ACE2 as a validated primary target for these miRNA. While miR-125b-5p indirectly modulates the expression of the Ace2 gene by targeting important transcription factors like Sp1 and STAT3, our data further elucidate that miR-125b-5p and/or miR-125a-5p directly reduce ACE2 levels by targeting ACE2 3’UTR mRNA. Additional work is warranted to investigate these specific regulatory mechanisms based on cell specificity, physiological conditions, and sex differences.

Targeting host inducible-heat shock protein 70 with PES-Cl is a promising antiviral strategy against SARS-CoV-2 infection and pathogenesis

One of the fundamental mechanisms developed by the host to contain the highly infectious and rapidly proliferating SARS-coronavirus is elevation of body temperature, a natural fallout of which is heat shock proteins over-expression. Here, for the first time, we demonstrate that the SARS-CoV-2 exploits the host Heat shock protein 70 (Hsp70) chaperone for its entry and propagation, and blocking it can combat the infection. SARS-CoV-2 infection as well as febrile temperature enhanced Hsp70 expression in host Vero E6 cells. Furthermore, heat shock or viral infection elevated the host cell autophagic response which is a prerequisite for viral propagation. In addition, Hsp70 protein demonstrated strong interaction with host Angiotensin-converting enzyme 2 (ACE2) as well as the receptor binding domain (RBD) of the SARS-CoV-2 Spike protein, indicating that interaction of Hsp70 with ACE2 and Spike protein may serve to protect them during febrile conditions. Suppressive and prophylactic treatment of Vero E6 cells with Hsp70 inhibitor PES, 2-(3-chlorophenyl) ethynesulfonamide (PES-Cl), abrogated viral infection more potently than the currently used drug Remdesivir. In conclusion, our study not only provides a fundamental insight into the role of host Hsp70 in SARS-CoV-2 pathogenesis, it paves the way for development of potent and irresistible anti-viral therapeutics.

Role of ACE2 and TMPRSS2 polymorphisms on COVID-19 outcome and disease severity in adult patients: A prospective cohort study in a tertiary hospital, Indonesia.

Coronavirus disease 2019 (COVID-19) has led to a significant number of infections and deaths worldwide, yet its pathogenesis and severity remain incompletely understood. Angiotensin-converting enzyme 2 (ACE2) and transmembrane protease, serine 2 (TMPRSS2), play crucial roles as receptors and molecules responsible for the virus's entry into host cells, initiating the infection process. Their polymorphisms have been extensively studied in relation to COVID-19 severity. The aim of this study was to examine the association of ACE2 (rs2074192) and TMPRSS2 (rs12329760) polymorphisms with COVID-19 outcome and severity. A prospective cohort study was conducted in 2022 at Haji Adam Malik Hospital, Medan, Indonesia. We randomly recruited hospitalized adult patients with COVID-19, confirmed by real-time polymerase chain reaction (RT-PCR). The baseline demographic data, disease severity, underlying disease, comorbidities, and COVID-19 vaccination status were collected. The single-nucleotide polymorphism (SNP) was assessed using TaqMan SNP genotyping assay, and the levels of TMPRSS2 and ACE2 proteins were measured using enzyme-linked immunosorbent assay (ELISA). A total of 151 COVID-19 patients were recruited and there were significant associations between age and severity with mortality outcomes. The age, kidney and lung diseases, and vaccination status were associated with severity levels. The results showed the CC genotype of ACE2 had the highest proportion, followed by TT and CT genotypes among patients, while CT was the most prevalent genotype, followed by CC and TT for TMPRSS2. This study did not find a significant association between ACE2 and TMPRSS2 genetic variants with disease severity and outcome but highlighted a specific association of TMPRSS2 SNP with mortality within the group. In addition, ACE2 concentration was significant different between mild-moderate and severe-critical COVID-19 groups (p=0.033).

The study of single nucleotide polymorphism in a promoter region of ACE-2 receptor gene in the samples of Iraqi population with COVID-19.

Angiotensin-converting enzyme 2 (ACE2) is an essential receptor on the host cell's cell membrane. It's interesting to note that the entry point receptor ACE2 protein and the severe acute respiratory syndrome (SARS) coronavirus are correlated. This study aimed to determine the influence of the ACE gene genotype and explore the effects of genetic variation in the promotor region of the ACE-2 gene receptor in SARS COV-2 patients. The 225 participants were categorized into two groups (75 infected and 150 control) according to the results of Real Time -polymerase chain reaction (RT-PCR), IgM, and IgG, also included two types of samples were collected for diagnosis hematological and molecular study. The hematological and biochemical parameters showed significant differences between the two studied groups according to D. dimer, ferritin, lactate dehydrogenase (LDH), C-reactive protein (CRP), white blood cells (WBC), lymphocyte, packed cell volume (PCV) (P˂0.0001), also red blood cell (RBC) (P = 0.0034). While the results of hemoglobin (HB) and platelet displayed non-significant differences between the two groups (p value 0.6811 and 0.9201 respectively). In addition, the sequencing result in the promotor of the ACE-2 gene detected novel eight polymorphisms and recorded them in NCBI under no. (ON959139). The ACE D/D polymorphism associated with increased levels of ACE could represent a genetic risk factor in addition the discovery stems from the prospect that genetic differences could lead to differing responses to COVID-19 therapies.

Serum Angiotensin II Level in Pediatric Patients with COVID-19 and its Correlation with the Disease Severity

Abstract Background Coronavirus disease 2019 (COVID-19) is a newly discovered RNA betacoronavirus infection. It has been caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Angiotensin II (Ang-II) is a mitochondrial toxin that under normal circumstances is rapidly removed by angiotensin converting enzyme 2 (ACE-2). SARS-CoV-2 uses the receptor ACE-2 for host cell entry and viral replication. ACE-2 proteins are occupied and downregulated by SARS-CoV-2. ACE-2 downregulation has been directly linked to toxic over accumulation of Ang-II. Accumulating Ang-II triggers many severe and fatal conditions such as acute respiratory distress syndrome (ARDS). Aim of the Work To assess the serum level of Ang-II and correlate it with the severity of COVID-19 infection in pediatric patients. Patients and Methods This case control study was conducted on 45 positive COVID-19 RT-PCR children who were compared to age and sex matched 45 healthy controls. Clinical examination, laboratory assays and imaging studies were done for the patients group to assess the severity of COVID–19 infection. Serum Ang-II was measured by ELISA for both groups and correlated with clinical (heart rate, blood pressure, respiratory rate and oxygen saturation), laboratory (total leucocytic count, lymphocytes, neutrophils, serum ferritin, ESR and CRP) and radiological (chest x-ray and CORAD score of CT chest ) parameters of the patients. Results The median “IQR” of serum Ang-II was significantly higher in the COVID-19 patients than in the controls (100 (88-137) ng/L) versus 20 (15-25) ng/L) (p-value= 0.001). There were statistically significant positive correlations between serum Ang-II levels and different grades of clinical severity classification (rs = 0.92, p-value=0.001) and CORAD score of CT chest. On the other hand, no statistically significant correlations were found between serum levels of Ang-II and total leucocytic count, lymphocytes, neutrophils, ESR and CRP. Conclusion Serum Ang-II could be used as a biomarker in predicting the severity of COVID-19 infection in pediatrics.

The Association of Withdrawing Maintenance Renin-Angiotensin System Inhibitor on All-Cause Mortality and Intensive Care Unit Admission Among Hypertensive Patients Admitted for Mild to Moderate COVID-19 infection:A Meta-analysis of Observational Studies

INTRODUCTION: The pandemic caused by coronavirus disease 2019 (COVID-19) posed a serious challenge to all health care systems in the world. It has been found to be harmful in people with underlying cardiovascular diseases, particularly in patients with systemic hypertension, which may be due to upregulation of angiotensin-converting enzyme 2 (ACE2) expression, which may lead to increased severe acute respiratory syndrome coronavirus 2 virulence. Renin-angiotensin system inhibitor (RASI) acts by blocking the angiotensin-converting enzyme and angiotensin II type 1 receptors, which in turn affects the production of the ACE2 protein. Hence, there have been arguments on whether to continue or discontinue this medication. Given the widespread use of RASIs globally and the fact that they are generally cardioprotective, research into the safety of continuing these maintenance medications in patients hospitalized with mild to moderate COVID-19 is immensely needed. METHODS: This meta-analysis involved review of observational studies among hypertensive patients on maintenance ACE inhibitor or angiotensin-receptor blocker with confirmed mild to moderate COVID-19 infection. Analyses were performed to determine the adjusted hazard ratio of each event using the raw data obtained from each study. Random-effects model and Cochran-Mantel-Haenszel method were utilized at 95% confidence interval. To check for heterogeneity, χ2 test and I2 statistic were calculated. Cochrane ReviewManager (RevMan version 5.3) was used for data analysis, and forest plots were generated. RESULTS: At 95% confidence interval, the adjusted hazard ratios for all-cause mortality and intensive care unit (ICU) admission at 95% confidence interval were 1.64 (1.22, 2.21) and 1.93 (1.34, 2.79), respectively. The tests of overall estimate effect for both outcomes were P < 0.0001 for all-cause mortality and P = 0.0003 for ICU admission. CONCLUSION: Discontinuation of maintenance RASI during hospitalization is associated with increased all-cause mortality and ICU admission among hypertensive patients with mild to moderate COVID-19 infection. KEYWORDS: angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, coronavirus, COVID-19, renin-angiotensin system inhibitor

The flavonoid quercetin decreases ACE2 and TMPRSS2 expression but not SARS-CoV-2 infection in cultured human lung cells.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds to angiotensin-converting enzyme 2 (ACE2) on host cells, via its spike protein, and transmembrane protease, serine 2 (TMPRSS2) cleaves the spike-ACE2 complex to facilitate virus entry. As rate-limiting steps for virus entry, modulation of ACE2 and/or TMPRSS2 may decrease SARS-CoV-2 infectivity and COVID-19 severity. In silico modeling suggested the natural bioactive flavonoid quercetin can bind to ACE2 and a recent randomized clinical trial demonstrated that oral supplementation with quercetin increased COVID-19 recovery. A range of cultured human cells were assessed for co-expression of ACE2 and TMPRSS2. Immortalized Calu-3 lung cells, cultured and matured at an air-liquid interface (Calu-3-ALIs), were established as the most appropriate. Primary bronchial epithelial cells (PBECs) were obtained from healthy adult males (N = 6) and cultured under submerged conditions to corroborate the outcomes. Upon maturation or reaching 80% confluence, respectively, the Calu-3-ALIs and PBECs were treated with quercetin, and mRNA and protein expression were assessed by droplet digital PCR and ELISA, respectively. SARS-CoV-2 infectivity, and the effects of pre- and co-treatment with quercetin, was assessed by median tissue culture infectious dose assay. Quercetin dose-dependently decreased ACE2 and TMPRSS2 mRNA and protein in both Calu-3-ALIs and PBECs after 4 h, while TMPRSS2 remained suppressed in response to prolonged treatment with lower doses (twice daily for 3 days). Quercetin also acutely decreased ADAM17 mRNA, but not ACE, in Calu-3-ALIs, and this warrants further investigation. Calu-3-ALIs, but not PBECs, were successfully infected with SARS-CoV-2; however, quercetin had no antiviral effect, neither directly nor indirectly through downregulation of ACE2 and TMPRSS2. Calu-3-ALIs were reaffirmed to be an optimal cell model for research into the regulation of ACE2 and TMPRSS2, without the need for prior genetic modification, and will prove valuable in future coronavirus and respiratory infectious disease work. However, our data demonstrate that a significant decrease in the expression of ACE2 and TMPRSS2 by a promising prophylactic candidate may not translate to infection prevention.

An analysis combining proteomics and transcriptomics revealed a regulation target of sea cucumber autolysis

Sea cucumber is a valuable seafood product and autolysis is the main concern for the aquaculture industry. This study employed proteomics and transcriptomics to investigate the autolysis mechanism of sea cucumbers. The fresh sea cucumber was exposed to UV light to induce autolysis. The body wall samples were cut off to analyze by proteomics and transcriptomics. The angiotensin-converting enzyme (ACE) inhibitor of teprotide and the activator of imatinib were gastric gavage to live sea cucumbers, respectively, to identify the regulation target. Autolysis occurrence was evaluated by appearance, soluble peptide, and hydroxyproline content. Four gene-protein pairs were ACE, AJAP10923, Heme-binding protein 2-like, and Ficolin-2-like. Only the ACE protein and gene changed synchronously and a significant down-regulation of ACE occurred in the autolysis sea cucumbers. Teprotide led to a 1.58-fold increase in the TCA-soluble protein content and a 1.57-fold increase in hydroxyproline content. No significant differences were observed between imatinib-treated sea cucumbers and fresh ones regarding TCA-soluble protein content or hydroxyproline levels (P > 0.05). ACE inhibitor accelerated the autolysis of sea cucumber, but ACE activator inhibited the autolysis. Therefore, ACE can serve as a regulatory target for autolysis in sea cucumbers.

SARS-CoV-2 Spike Protein Enhances Carboxypeptidase Activity of Angiotensin-Converting Enzyme 2.

In this study, we investigated whether severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike protein may modify angiotensin-converting enzyme 2 (ACE2) activity in the plasma, heart, kidney, liver, lung, and six brain regions (amygdala, brain stem, cortex, hippocampus, hypothalamus, and striatum) of diabetic and hypertensive rats. We determine ACE2 activity in the plasma and lysates of heart, kidney, liver, lung, and six brain regions. MLN-4760 inhibits ACE2 activity in the plasma and all organs. On the other hand, soluble ACE2 (sACE2) activity increased in the plasma of diabetic rats, and there was no change in the plasma of hypertensive rats. ACE2 activity was augmented in the liver, brain stem, and striatum, while it decreased in the kidney, amygdala, cortex, and hippocampus of diabetic rats. ACE2 activity increased in the kidney, liver, and lung, while it decreased in the heart, amygdala, cortex, and hypothalamus of hypertensive rats. We measured the ACE2 content via enzyme-linked immunosorbent assay and found that ACE2 protein levels increased in the heart, while it decreased in the plasma, kidney, brain stem, cortex, hippocampus, hypothalamus, and striatum of diabetic rats. ACE2 protein levels decreased in the brain stem, cortex, hippocampus, and hypothalamus of hypertensive rats. Our data showed that the spike protein enhanced ACE2 activity in the liver and lungs of diabetic rats, as well as in the heart and three of the brain regions (cortex, hypothalamus, and striatum) of hypertensive rats.

Anti-SARS-CoV-2 Viral Activity of Sweet Potato Trypsin Inhibitor via Downregulation of TMPRSS2 Activity and ACE2 Expression In Vitro and In Vivo.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic. Known as COVID-19, it has affected billions of people worldwide, claiming millions of lives and posing a continuing threat to humanity. This is considered one of the most extensive pandemics ever recorded in human history, causing significant losses to both life and economies globally. However, the available evidence is currently insufficient to establish the effectiveness and safety of antiviral drugs or vaccines. The entry of the virus into host cells involves binding to angiotensin-converting enzyme 2 (ACE2), a cell surface receptor, via its spike protein. Meanwhile, transmembrane protease serine 2 (TMPRSS2), a host surface protease, cleaves and activates the virus's S protein, thus promoting viral infection. Plant protease inhibitors play a crucial role in protecting plants against insects and/or microorganisms. The major storage proteins in sweet potato roots include sweet potato trypsin inhibitor (SWTI), which accounts for approximately 60% of the total water-soluble protein and has been found to possess a variety of health-promoting properties, including antioxidant, anti-inflammatory, ACE-inhibitory, and anticancer functions. Our study found that SWTI caused a significant reduction in the expression of the ACE2 and TMPRSS2 proteins, without any adverse effects on cells. Therefore, our findings suggest that the ACE2 and TMPRSS2 axis can be targeted via SWTI to potentially inhibit SARS-CoV-2 infection.

Ligand- and Structure-Based Virtual Screening Identifies New Inhibitors of the Interaction of the SARS-CoV-2 Spike Protein with the ACE2 Host Receptor.

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a fast-spreading viral pathogen and poses a serious threat to human health. New SARS-CoV-2 variants have been arising worldwide; therefore, is necessary to explore more therapeutic options. The interaction of the viral spike (S) protein with the angiotensin-converting enzyme 2 (ACE2) host receptor is an attractive drug target to prevent the infection via the inhibition of virus cell entry. In this study, Ligand- and Structure-Based Virtual Screening (LBVS and SBVS) was performed to propose potential inhibitors capable of blocking the S receptor-binding domain (RBD) and ACE2 interaction. The best five lead compounds were confirmed as inhibitors through ELISA-based enzyme assays. The docking studies and molecular dynamic (MD) simulations of the selected compounds maintained the molecular interaction and stability (RMSD fluctuations less than 5 Å) with key residues of the S protein. The compounds DRI-1, DRI-2, DRI-3, DRI-4, and DRI-5 efficiently block the interaction between the SARS-CoV-2 spike protein and receptor ACE2 (from 69.90 to 99.65% of inhibition) at 50 µM. The most potent inhibitors were DRI-2 (IC50 = 8.8 µM) and DRI-3 (IC50 = 2.1 µM) and have an acceptable profile of cytotoxicity (CC50 > 90 µM). Therefore, these compounds could be good candidates for further SARS-CoV-2 preclinical experiments.

In silico identification of approved drugs for potential prophylactic uses against SARS-CoV-2 infection

The outbreak of Severe Acute Respiratory Syndrome Corona Virus (SARS-CoV-2) responsible for Coronavirus disease 2019 (COVID-19) constitute a major public health threat and economic burden. Despite the multifold research all over the world. COVID-19 has remained without a treatment. Hence, the urgent need to repurpose the FDA-approved drugs through in silico computational technique to identify inhibitors of SARS-CoV-2. Bioinformatics techniques were used to screen 2015 FDA- approved drugs against SARS-CoV-2 proteins and associated human protein, angiotensin-converting enzyme 2 (ACE2) to identify drug for new indication. The ligands were downloaded from Selleckchem drug data bank in SDF format. Open Babel was used to separate the ligands into their compounds and prepared for docking simulation using shell script and saved as PDBQT. Experimental crystal structures of the receptors (ACE2 and Spike proteins) were retrieved from Protein Data Bank (PDB), Autodock tools was used to prepare the proteins and saved as PDBQT files. Docking protocols were validated, molecular docking simulations were performed on a Linux platform using AutoDock Vina in quadruplicate. The binding energies (BEs) kcal/mol were calculated and expressed as mean ± standard deviation. Discovery studio was used for visualization. Density Functional Theory (DFT) was used to determine the predictive maximal inhibitory concentration (pIC50) of best hits. Ninety-one (91) new hits were identified for prophylaxis. Four (4) compounds were subjected to DFT based IC50 calculation with molnupiravir as a reference compound. Significantly, calculated IC50 of molnupiravir in Vero cells and Calu-3 were 0.299 and 0.008µM respectively while the experimental IC50 in Vero cells and Calu-3 as reported in literature were 0.3 and 0.08 µM respectively. The newly identified hits are promising therapeutic agents and there is no significant difference between the experimental IC50 of molnupiravir and the calculated IC50.

Susceptibility and transmissibility of SARS-CoV-2 variants in transgenic mice expressing the cat angiotensin-converting enzyme 2 (ACE-2) receptor

The emergence of SARS-CoV-2 in 2019 and its rapid spread throughout the world has caused the largest pandemic of our modern era. The zoonotic origin of this pathogen highlights the importance of the One Health concept and the need for a coordinated response to this kind of threats. Since its emergence, the virus has caused >7 million deaths worldwide. However, the animal source for human outbreaks remains unknown. The ability of the virus to jump between hosts is facilitated by the presence of the virus receptor, the highly conserved angiotensin-converting enzyme 2 (ACE2), found in various mammals. Positivity for SARS-CoV-2 has been reported in various species, including domestic animals and livestock, but their potential role in bridging viral transmission to humans is still unknown. Additionally, the virus has evolved over the pandemic, resulting in variants with different impacts on human health. Therefore, suitable animal models are crucial to evaluate the susceptibility of different mammalian species to this pathogen and the adaptability of different variants. In this work, we established a transgenic mouse model that expresses the feline ACE2 protein receptor (cACE2) under the human cytokeratin 18 (K18) gene promoter's control, enabling high expression in epithelial cells, which the virus targets. Using this model, we assessed the susceptibility, pathogenicity, and transmission of SARS-CoV-2 variants. Our results show that the sole expression of the cACE2 receptor in these mice makes them susceptible to SARS-CoV-2 variants from the initial pandemic wave but does not enhance susceptibility to omicron variants. Furthermore, we demonstrated efficient contact transmission of SARS-CoV-2 between transgenic mice that express either the feline or the human ACE2 receptor.

Two novel angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibiting peptides from tilapia (Oreochromis mossambicus) skin and their molecular docking mechanism.

In the study, papain was used to hydrolyze tilapia (Oreochromis mossambicus) skin to obtain a tilapia skin hydrolysate (TSH) with dual angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibitory activities. The resulting TSH was sequentially fractionated by ultrafiltration, size exclusion separation chromatography, and reverse-phase high-performance liquid chromatography. Its inhibitory effects on ACE and DPP-IV were determined by commercial reagent kits. Two peptides purified from TSH were identified as Gly-Pro-Leu-Gly-Ala-Leu (GPLGAL) and Lys-Pro-Ala-Gly-Asn (KPAGN) by the ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Inhibitory concentration (IC50) of GPLGAL on ACE and DPP-IV were 117.20±1.69 and 187.10±2.75µM, respectively. IC50 of KPAGN on ACE and DPP-IV were 137.40±2.33 and 259.20±2.85µM, respectively. The molecular simulation demonstrated that the binding affinities of GPLGAL to ACE and DPP-IV proteins were -8.5 and -7.4kcal/mol, respectively, whereas those of KPAGN to ACE and DPP-IV proteins were -7.9 and -6.7kcal/mol, respectively. GPLGAL interacted with 21 amino acid residues of the ACE active site, whereas KPAGN engaged with 19 amino acid residues. Additionally, GPLGAL interacted with 10 amino acid residues of the DPP-IV active site, whereas KPAGN engaged with 13 amino acid residues. The two peptides predominantly occupied the active sites of ACE (His513, Tyr523, and Ala354) and DPP-IV (Tyr662 and Arg125) through hydrogen bonding. This leads to the deactivation of ACE and DPP-IV. PRACTICAL APPLICATION: Accelerate tilapia skin development and high-value utilization; provide foundation for preparing the peptides with dual ACE and DPP-IV inhibiting activity.

Discovery of components in honeysuckle for treating COVID-19 and diabetes based on molecular docking, network analysis and experimental validation.

Molecular docking screening identified ochnaflavone, madreselvin B and hydnocarpin as key components for treating COVID-19 with diabetes in honeysuckle using 3 C-like protease (Mpro), angiotensin-converting enzyme 2 (ACE2), and dipeptidyl peptidase 4 (DPP4) as molecular docking targets, ACE2, DPP4, IL2, NFKB1, PLG, TBK1, TLR4 and TNF were the core targets, and multiple antiviral and anti-inflammatory signalling pathways were involved. Further, the levels of IL-1β and DPP4 in cell supernatant that had been activated by LPS was decreased by hypnocarpin, and ACE2 protein and DPP4 mRNA in cells were down-regulated. Overall, we have identified three components from honeysuckle that have potency to treat COVID-19 combined with diabetes. SARS-CoV-2 transcription may be inhibited by these components in honeysuckle, reducing virus invasion, inhibiting inflammatory factors, and improving immune response. Our findings could provide a basis for the clinical application and further development of honeysuckle.