LitCovid-sentences  

PMC:7408073 / 53765-61651 JSONTXT 11 Projects

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Id Subject Object Predicate Lexical cue
T259 0-4 Sentence denotes 5.2.
T260 5-71 Sentence denotes Safety and Efficacy Concerns of MLN4760 and Dx600 ACE2 Inhibitors.
T261 72-211 Sentence denotes It is known that the catalytic cleft of ACE2 consists of two peptidase subdomains: one membrane-distal and the other one membrane-proximal.
T262 212-332 Sentence denotes Their weak interactions are consistent with the ability to transition from open to the closed ACE2 conformation [28,90].
T263 333-608 Sentence denotes Indeed, the two subdomains undergo a large hinge-bending motion in which membrane-proximal subdomain remains almost unchanged, while membrane-distal subdomain moves to close the distance between the two subdomains, mimicking the opening/closing movement of a clam shell [90].
T264 609-899 Sentence denotes ACE2 open conformation likely reflects free state of the enzyme available to catch substrates (or inhibitors), then, when the ACE2 receptor binds to a substrate, the membrane-distal subdomain closes around the substrate (or the inhibitor), finally performing the enzymatic activity [24,90].
T265 900-1080 Sentence denotes Interestingly, in cryo–electron microscopy structures of full-length human ACE2, only the closed/substrate-bound conformation of ACE2 was observed in the spike-ACE2 complexes [28].
T266 1081-1325 Sentence denotes Since human ACE2 is assembled on cell surface as a homodimer [28], binding of the spike protein trimer onto ACE2 dimer suggests simultaneous binding of two spike protein trimers to substrate-bound conformer of ACE2 homodimer on plasma membrane.
T267 1326-1582 Sentence denotes The spike binding sites on ACE2 homodimer are localized above the membrane-distal peptidase subdomain of each ACE2 monomer, nevertheless neither ACE2 shedding nor ACE2 binding to spike proteins have been shown to inhibit ACE2 enzymatic activity [16,17,24].
T268 1583-1850 Sentence denotes On the other hand, the S-protein-binding region of membrane-distal ACE2 subdomain is not significantly perturbed by the receptor conformational changes and maintains the ability to associate with soluble spike proteins independently on open/closed conformations [24].
T269 1851-2053 Sentence denotes Interestingly, an ACE2 specific inhibitor (MLN-4760) has been shown to induce the closed (inhibitor-bound) ACE2 structure [90] and to retain its inhibitory effects on sACE2 bound to spike proteins [24].
T270 2054-2254 Sentence denotes MLN4760 is a potent and selective human ACE2 inhibitor (IC50 = 0.44 nM against soluble human ACE2) whose synthesis produces a racemic mixture of two diastereomers that showed 75:25 ratio for Isomer A:
T271 2255-2364 Sentence denotes Isomer B [113,114] and the purified isomer B is the isomer commercially available from Merck Millipore [114].
T272 2365-2550 Sentence denotes Testing MLN-4760 racemic mixture and its isomers, it was observed a concentration-dependent inhibition of recombinant human (rh)ACE or rhACE2 activities with all three inhibitors [114].
T273 2551-2901 Sentence denotes The isomer B was less selective (near minimal-maximal rhACE inhibition range 10−6M-10−4M) than the racemate or the isomer A (near minimal-maximal rhACE inhibition range 10−6M-10−2M) and less effective (near maximal rhACE2 inhibition at 10−7M) than the racemate or the isomer A (near maximal rhACE2 inhibition at 10−8 M) for rhACE2 versus rhACE [114].
T274 2902-3268 Sentence denotes Moreover, all three inhibitors exerted a significantly higher inhibitory activity against soluble than membrane-bound forms of (m)ACE2 (near maximal mACE2 inhibition at 10−6M), being the isomer B more selective and effective than the racemate or the isomer A for mACE2 vs. mACE expressed on the surface of mononuclear cells (or CD34 hematopoietic progenitors) [114].
T275 3269-3368 Sentence denotes A second ACE2 inhibitor, Dx600, produced similar results to those obtained with the isomer B [114].
T276 3369-3535 Sentence denotes Another study evaluated the inhibitory activity of both MLN-4760 and DX600 (either the linear conformational form or the disulfide bridged cyclic variant) inhibitors.
T277 3536-3747 Sentence denotes In this report, the experiments were performed at pH 6.5 [115], a pH at which rhACE2 proteolysis operates at maximal activity [79] and a condition that resembles hypercapnic acidosis which may occur during SARS.
T278 3748-4084 Sentence denotes MLN-4760 was still able to strongly and specifically inhibit rhACE2 activity (near maximal inhibition at 10−8 M), preventing rhACE2-driven Ang II degradation into Ang (1–7), whereas DX600 (either linear or cyclic variant) inhibits rhACE2 at relatively higher concentration (near maximal inhibition at 10−6 M–10−7 M, respectively) [115].
T279 4085-4229 Sentence denotes Altogether these data indicate that the racemate or the isomer A are more effective in inhibiting soluble forms of ACE2 than isomer B and Dx600.
T280 4230-4583 Sentence denotes Therefore, these inhibitors at opportune (low) concentrations are expected to preferentially reduce systemic sACE2 activity, while preserving the ACE2 activity of (local) membrane-associated forms of ACE2, knowing that catalytic activity of circulating ACE2 was undetectable in human plasma of healthy subjects due to an endogenous ACE2 inhibitor [116].
T281 4584-4939 Sentence denotes Since MLN-4760 inhibitor promotes the closed ACE2 conformation [90] which is the preferential conformer for virus binding [28], MLN-4760 is expected to not prevent viral entry; nevertheless, its inhibitory function on ACE2 pathway might work on the positive feedback loops (above described) that ultimately favour ACE2 membrane expression and viral entry.
T282 4940-5057 Sentence denotes A potential risk factor of inhibiting the Ang II metabolization into Ang 1–7 could be the increase of blood pressure.
T283 5058-5567 Sentence denotes Although ACE2 pathway inhibition might lead to hypertensive effects, treatment with MLN-4760 for 4-5 weeks had no effect on blood pressure when administered 10 mg/kg/day in drinking water in wild type mice [117] nor in male (mRen2)27 transgenic hypertensive rats (administered 30 mg/kg/day subcutaneously via mini-osmotic pumps) [118], suggesting that hypertensive activity mediated by ACE2 inhibition is promptly balanced by compensatory mechanisms either in normal or hypertensive blood pressure conditions.
T284 5568-5773 Sentence denotes In addition, injections of MLN4760 into the nucleus tractus solitarii has been shown to reduce the baroreceptor reflex in rats, suggesting a role for ACE2 in controlling a reflex bradycardia (see [39,44]).
T285 5774-6008 Sentence denotes Finally, chronic inhibition of ACE2 with MLN-4760 led to increase of ACE, albuminuria and glomerular injury in streptozotocin-induced diabetic mice, indicating a possible adverse effect of the inhibitor in a diabetic background [119].
T286 6009-6182 Sentence denotes Extensive experiments have been also performed with DX600, a specific peptide ACE2 inhibitor that exhibited a mixed competitive and non-competitive type of inhibition [120].
T287 6183-6280 Sentence denotes Actually, several reports describing Dx600 inhibitor administration in mice suggest its safe use.
T288 6281-6561 Sentence denotes Of interest, a report described its (safe) use alone (1 mg/kg per day) by nasal inhalation for 3 days in a mouse model of endotoxin-induced lung inflammation [121]; however, this inhibitor is less efficacious than MLN-4760 in inhibiting the soluble forms of human rACE2 [114,115].
T289 6562-6758 Sentence denotes Altogether these reports on administration of ACE2 inhibitors do not reveal significant adverse impacts or mortality in experimental animals, which suggests their safety in chronic administration.
T290 6759-6858 Sentence denotes This was also confirmed in human clinical trials with MLN-4760 (clinical name: ORE1001, see later).
T291 6859-7378 Sentence denotes Of interest, a report showed that on day 28 post-myocardial infarction, adult male Sprague-Dawley rats that had received MLN-4760 (also called C16) 25 mg/mL/day by daily intraperitoneal injection (as a solution of 42 mg/mL in distilled water) tended to have lower left ventricular pulse pressure, mean arterial pressures and left ventricular relaxation time constant-Tau compared to untreated group (see table 2 of the paper) [52], suggesting a possible protective role of ACE2 inhibition in post-myocardial infarction.
T292 7379-7659 Sentence denotes Therefore, MLN-4760 might be helpful not only for COVID-19 but also in targeted therapies for pathologies correlated with an excessive increase of ACE2 activity that may involve heart, lung, liver, colon or other tissues/organs expressing ACE2 such as blood and endothelial cells.
T293 7660-7886 Sentence denotes As an example, GL1001 (old name of MLN-4760) showed to produce an anti-inflammatory activity in a mouse model of colitis [122], highlighting the importance of the yin-yang balance of ACE/ACE2 pathways (“in medio stat virtus”).