Ectodomain shedding of proteins important for SARS-CoV-2 pathogenesis in plasma of tobacco cigarette smokers compared to electronic cigarette vapers: a cross-sectional study.

The impact of tobacco cigarette (TCIG) smoking and electronic cigarette (ECIG) vaping on the risk of development of severe COVID-19 is controversial. The present study investigated levels of proteins important for SARS-CoV-2 pathogenesis present in plasma because of ectodomain shedding in smokers, ECIG vapers, and non-smokers (NSs). Protein levels of soluble angiotensin-converting enzyme 2 (ACE2), angiotensin (Ang) II (the ligand of ACE2), Ang 1-7 (the main peptide generated from Ang II by ACE2 activity), furin (a protease that increases the affinity of the SARS-CoV-2 spike protein for ACE2), and products of ADAM17 shedding activity that predict morbidity in COVID-19 (IL-6/IL-6R alpha (IL-6/IL-6Rα) complex, soluble CD163 (sCD163), L-selectin) were determined in plasma from 45 NSs, 30 ECIG vapers, and 29 TCIG smokers using ELISA. Baseline characteristics of study participants did not differ among groups. TCIG smokers had increased sCD163, L-selectin compared to NSs and ECIG vapers (p < 0.001 for all comparisons). ECIG vapers had higher plasma furin compared to both NSs (p < 0.001) and TCIG smokers (p < 0.05). ECIG vaping and TCIG smoking did not impact plasma ACE2, Ang 1-7, Ang II, and IL-6 levels compared to NSs (p > 0.1 for all comparisons). Further studies are needed to determine if increased furin activity and ADAM17 shedding activity that is associated with increased plasma levels of sCD163 and L-selectin in healthy young TCIG smokers may contribute to the future development of severe COVID-19 and cardiovascular complications of post-acute COVID-19 syndrome.

Decrease in Angiotensin-Converting Enzyme activity but not concentration in plasma/lungs in COVID-19 patients offers clues for diagnosis/treatment.

Although several therapeutics are used to treat coronavirus disease 2019 (COVID-19) patients, there is still no definitive metabolic marker to evaluate disease severity and recovery or a quantitative test to end quarantine. Because severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infects human cells via the angiotensin-converting-enzyme 2 (ACE2) receptor and COVID-19 is associated with renin-angiotensin system dysregulation, we evaluated soluble ACE2 (sACE2) activity in the plasma/saliva of 80 hospitalized COVID-19 patients and 27 non-COVID-19 volunteers, and levels of ACE2/Ang (1-7) in plasma or membrane (mACE2) in lung autopsy samples. sACE2 activity was markedly reduced (p < 0.0001) in COVID-19 plasma (n = 59) compared with controls (n = 27). Nadir sACE2 activity in early hospitalization was restored during disease recovery, irrespective of patient age, demographic variations, or comorbidity; in convalescent plasma-administered patients (n = 45), restoration was statistically higher than matched controls (n = 22, p = 0.0021). ACE2 activity was also substantially reduced in the saliva of COVID-19 patients compared with controls (p = 0.0065). There is a strong inverse correlation between sACE2 concentration and sACE2 activity and Ang (1-7) levels in participant plasmas. However, there were no difference in membrane ACE2 levels in lungs of autopsy tissues of COVID-19 (n = 800) versus other conditions (n = 300). These clinical observations suggest sACE2 activity as a potential biomarker and therapeutic target for COVID-19.

Potential role of bradykinin and its receptors in COVID-19

Bradykinin (BK) is a nonapeptide that belongs to the kinin family. It is an active inflammatory mediator that exerts multiple different effects via its B1 and B2 receptors (B1R and B2R);however, its role has not been fully elucidated so far. It is known that B1R and B2R interact with angiotensin-converting enzyme (ACE)-2 protein, which acts as a receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19). By degrading BK to its desARG9-BK metabolite, ACE2 leads to B1R activation, which triggers a release of pro-and anti-inflammatory cytokines in an immune response to infectious pathogens. On the other hand, ACE2 stimulates the expression of B2R by activating the ANG(1-7)-MasR axis which is essential for proper endothelial function. A controlled increase in B1R-mediated cytokine release during SARS-CoV-2 cell entry may be considered a normal immune response aiming to prevent infection. However, if regulatory mechanisms fail, the increase in proinflammatory cytokine release may lead to progression of infection, endothelial activation, and onset of symptoms, including organ involvement. Available data strongly suggest that BK and its receptors are involved in the pathomechanism of COVID-19 and linked by various feedback mechanisms to ACE2, ACE1, as well as angiotensin II (ANGII) and its receptors. As expression of these pathways is likely to change dynamically throughout different stages of COVID-19, novel treatment options that target these pathways along with close monitoring of their activity should be developed.

Ibuprofen, Flurbiprofen, Etoricoxib or Paracetamol Do Not Influence ACE2 Expression and Activity In Vitro or in Mice and Do Not Exacerbate In-Vitro SARS-CoV-2 Infection.

SARS-CoV-2 uses the human cell surface protein angiotensin converting enzyme 2 (ACE2) as the receptor by which it gains access into lung and other tissue. Early in the pandemic, there was speculation that a number of commonly used medications-including ibuprofen and other non-steroidal anti-inflammatory drugs (NSAIDs)-have the potential to upregulate ACE2, thereby possibly facilitating viral entry and increasing the severity of COVID-19. We investigated the influence of the NSAIDS with a range of cyclooxygenase (COX)1 and COX2 selectivity (ibuprofen, flurbiprofen, etoricoxib) and paracetamol on the level of ACE2 mRNA/protein expression and activity as well as their influence on SARS-CoV-2 infection levels in a Caco-2 cell model. We also analysed the ACE2 mRNA/protein levels and activity in lung, heart and aorta in ibuprofen treated mice. The drugs had no effect on ACE2 mRNA/protein expression and activity in the Caco-2 cell model. There was no up-regulation of ACE2 mRNA/protein expression and activity in lung, heart and aorta tissue in ibuprofen-treated mice in comparison to untreated mice. Viral load was significantly reduced by both flurbiprofen and ibuprofen at high concentrations. Ibuprofen, flurbiprofen, etoricoxib and paracetamol demonstrated no effects on ACE2 expression or activity in vitro or in vivo. Higher concentrations of ibuprofen and flurbiprofen reduced SARS-CoV-2 replication in vitro.

A novel strategy by integrating chemical profiling, molecular networking, chemical isolation, and activity evaluation to target isolation of potential anti-ACE2 candidates in Forsythiae Fructus.

BACKGROUND: Traditional Chinese medicine (TCM) is regarded as a large database containing hundreds to thousands of chemical constituents that can be further developed as clinical drugs, such as artemisinin in Artemisia annua. However, effectively exploring novel candidates is still a challenge faced by researchers. PURPOSE: In this work, an integrated strategy combining chemical profiling, molecular networking, chemical isolation, and activity evaluation (CMCA strategy) was proposed and applied to systematically characterize and screen novel candidates, and Forsythiae fructus (FF) was used as an example. STUDY DESIGN: It contained four parts. First, the chemical compounds in FF were detected by ultra-high-performance liquid chromatography-mass spectrometry (UPLC/Q-TOF MS) with data-dependent acquisition, and further, the targeted compounds were screened out based on an in-house database. In the meantime, the representative MS/MS fragmentation behaviors of different chemical structure types were summarized. Second, homologous constituents were grouped and organized based on feature-guided molecular networking, and the nontargeted components with homologous mass fragmentation behaviors were characterized. Third, the novel compounds were isolated and unambiguously identified by nuclear magnetic resonance (NMR). Finally, the anti-angiotensin-converting enzyme 2 (ACE2) activities of isolated chemical constituents were further evaluated by in vitro experiments. RESULTS: A total of 278 compounds were profiled in FF, including 151 targeted compounds and 127 nontargeted compounds. Among them, 16 were unambitiously identified by comparison with reference standards. Moreover, 25 were classified into potential novel compounds. Two novel compounds were unambiguously identified by using conventional chromatographic methods, and they were named phillyrigeninside D (peak 254) and forsythenside O (peak 155). Furthermore, the ACE2 activity of the compounds in FF was evaluated by modern pharmacological methods, and among them, suspensaside A was confirmed to present obvious anti-ACE2 activity. CONCLUSION: Our work provides meaningful information for revealing potential FF candidates for the treatment of COVID-19, along with new insight for exploring novel candidates from complex systems.

Level of the SARS-CoV-2 receptor ACE2 activity is highly elevated in old-aged patients with aortic stenosis: implications for ACE2 as a biomarker for the severity of COVID-19.

Coronavirus disease 2019 (COVID-19) has a high mortality in elderly patients with pre-existing cardiovascular diseases. The cellular receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the angiotensin-converting enzyme 2 (ACE2), thereby implicating a link between cardiovascular diseases and SARS-CoV-2 susceptibility. Aortic stenosis (AS) represents a chronic inflammatory state with severe cardiovascular complications in the elderly, a prime condition for COVID-19 mortality. The circulating ACE2 levels were measured in 111 patients with severe AS and compared to patients with hypertension and healthy individuals. About 4 times higher circulating ACE2 activity was found in patients with severe AS than in hypertensives or healthy individuals (88.3 ± 61.6., n = 111, 20.6 ± 13.4, n = 540, and 16.1 ± 7.4 mU/L, n = 46, respectively). Patients with severe AS were older than patients with hypertension (80 ± 6 years vs. 60 ± 15 years, P < 0.05). Serum ACE2 activity correlated negatively with the left ventricular ejection fraction, aortic root area, TAPSE, and positively with the right ventricular systolic pressure, cardiac diameters in patients with AS. In contrast, circulating ACE2 activity was independent of the blood pressure, peak flow velocity at the aortic root, kidney function (GFR), and inflammatory state (CRP). We found no effect of RAAS inhibitory drugs on the serum ACE2 activity in this group of patients. Our results illustrate circulating ACE2 as a potential interface between chronic inflammation, cardiovascular disease, and COVID-19 susceptibility. Elderly patients with AS have markedly elevated ACE2 levels together with altered left and right ventricular functions, which may pose higher risks during COVID-19. Our clinical data do not support a role for RAAS inhibitors in regulating circulating ACE2 levels.