Evaluating Molecular Mechanism of Hypotensive Peptides Interactions with Renin and Angiotensin Converting Enzyme

<div><p>Our previous study showed that three rapeseed protein-derived peptides (TF, LY and RALP) inhibited the <i>in vitro</i> activities of angiotensin converting enzyme (ACE) and renin. Oral administration of these peptides to spontaneously hypertensive rats led to reductions in systolic blood pressure. In the present work, we examined the potential molecular mechanisms responsible for the ACE- and renin-inhibitory activities of these peptides. Enzyme inhibition kinetics showed competitive, non-competitive and mixed-type peptide-dependent inhibition of renin and ACE activities. Intrinsic fluorescence intensity data showed that LY and RALP have stronger binding effects on ACE molecule compared to that of TF. LY and RALP showed the highest inhibition of ACE and renin activities, respectively. Circular dichroism data showed that the inhibitory mechanism involved extensive peptide-dependent reductions in α-helix and β-sheet fractions of ACE and renin protein conformations. Molecular docking studies confirmed that the higher renin-inhibitory activity of RALP may be due to formation of several hydrogen bonds (H-bonds) with the enzyme’s active site residues. The rapeseed peptides inhibited renin and ACE activities mostly through binding to enzyme active site or non-active sites and forming extensive H-bonds that distorted the normal configuration required for catalysis. Data presented from this work could enhance development of highly potent antihypertensive natural peptides or peptidomimetics.</p></div

Lineweaver-Burk plots of the inhibition of ACE and renin by peptides.

<p>(A) TF, (B) LY, and (C) RALP are at varying concentrations of ACE substrate (0.0625–0.5 mM), and V is rate of reaction (ΔA345 nm/min); (D) TF, (E) LY and (F) RALP are at varying concentrations of renin substrate (1.25–10 µM), and V is rate of reaction (FIU/min).</p

Molecular docking of the peptides at ACE and renin active sites.

<p>Results of peptide-ACE interactions are showed in A (TF), B (LY), C (RALP), and that of peptide-renin interactions are D (TF), E (LY), F (RALP). Enzyme hydrophobic residues are represented in red, positively charged residues are represented in blue, negatively charged residues and hydrogen bonds are represented in green, and other residues are represented automatically. (Image obtained with Accelrys DS Visualizer software).</p

Kinetics constants of renin-catalyzed reaction at different peptide concentrations.

<p><i>K_m</i> or <i>K</i>′<i>_m</i> is Michaelis-Menten constant in the absence (control) or presence of a peptide; <i>V_max</i> or <i>V</i>′<i>_max</i> is maximum reaction velocities in the absence (control) or presence of a peptide; <i>K_i</i> is the enzyme-inhibitor dissociation constant.</p

Kinetics constants of angiotensin converting enzyme-catalyzed reaction at different peptide concentrations.

<p><i>K_m</i> or <i>K</i>′<i>_m</i> is Michaelis-Menten constant in the absence (control) or presence of a peptide; <i>V_max</i> or <i>V</i>′<i>_max</i> is maximum reaction velocities in the absence (control) or presence of a peptide; <i>K_i</i> is the enzyme-inhibitor dissociation constant.</p

ACE (PDB: 1O86) and renin (PDB: 2V0Z) residues having at least one atom at a distance of 3.5 Å around the docked peptide.

<p>The residues around crystallized lisinopril and Aliskiren in the ACE and renin structures are also shown.</p

Emission spectra of ACE and renin proteins in the presence of peptides.

<p>Results of peptide-ACE interactions are showed in A (TF), B (LY), C (RALP), and that of peptide-renin interactions are D (TF), E (LY), F (RALP). In all cases λ_ex = 280 nm.</p

sj-docx-1-smo-10.1177_20503121231225874 – Supplemental material for Elexacaftor–tezacaftor–ivacaftor for cystic fibrosis with Phe508del mutation: Evidence from randomized controlled trials

Supplemental material, sj-docx-1-smo-10.1177_20503121231225874 for Elexacaftor–tezacaftor–ivacaftor for cystic fibrosis with Phe508del mutation: Evidence from randomized controlled trials by Rong He, Fei Lin, Zehui Deng and Bin Yu in SAGE Open Medicine</p

Correlation of δR2 and OD value.

<p>The change in δR2 and OD value was positively correlated, with statistical significance (r = 0.876, p<0.01).</p

DataSheet_1_Development and validation of cuproptosis-related lncRNAs associated with pancreatic cancer immune microenvironment based on single-cell.zip

BackgroundCuproptosis, a novel mode of cell death associated with the tricarboxylic acid (TCA) cycle, is relevant to the development of cancer. However, the impact of single-cell-based Cuproptosis-associated lncRNAs on the Tumor immune microenvironment (TIME) of Pancreatic adenocarcinoma (PAAD) and its potential value for individualized immunotherapy has not been clarified.Methods14 immune-related CRGs were screened by exploring the interaction between differentially expressed Immune-Related Genes (IRGs) and Cuproptosis-Related Genes (CRGs) in PAAD. Next, the expression amount and expression distribution of CRGs in single-cell samples were analyzed by focusing on 7-CRGs with significant expressions. On the one hand, MAP2K2, SOD1, and VEGFA, which were significantly differentially expressed between PAAD sites and normal tissues adjacent to them, were subjected to immunohistochemical validation and immune landscape analysis. On the other hand, from these 7-CRGs, prognostic signatures of lncRNAs were established by co-expression and LASSO-COX regression analysis, and their prognostic value and immune relevance were assessed. In addition, this study not only validated the hub CRGs and the lncRNAs constituting the signature in a PAAD animal model treated with immunotherapy-based combination therapy using immunohistochemistry and qRT-PCR but also explored the potential value of the combination of targeted, chemotherapy and immunotherapy.ResultsBased on the screening of 7-CRGs significantly expressed in a PAAD single-cell cohort and their co-expressed Cuproptosis-Related lncRNAs (CRIs), this study constructed a prognostic signature of 4-CRIs named CIR-score. A Nomogram integrating the CIR-score and clinical risk factors was constructed on this basis to predict the individualized survival of patients. Moreover, high and low-risk groups classified according to the median of signatures exhibited significant differences in clinical prognosis, immune landscape, bioenrichment, tumor burden, and drug sensitivity. And the immunohistochemical and qRT-PCR results of different mouse PAAD treatment strategies were consistent with the trend of inter-group variability in drug sensitivity of hub CRGs and CIR-score. The combination of immunotherapy, targeted therapy, and chemotherapy exhibited a better tumor suppression effect.ConclusionCIR-score, as a Cuproptosis-related TIME-specific prognostic signature based on PAAD single cells, not only predicts the prognosis and immune landscape of PAAD patients but also provides a new strategy for individualized immunotherapy-based combination therapy.</p