Structure-Activity Relationship Studies of N- and C-Terminally Modified Secretin Analogs for the Human Secretin Receptor

Singh, K. N.; Senthil, Vijayalakshmi; Arokiaraj, Aloysius Wilfred Raj; Leprince, Jérôme; Lefranc, Benjamin; Vaudry, David; Allam, Ahmed A.; Ajarem, Jamaan S.; Chow, Billy K. C.

doi:10.1371/journal.pone.0149359

Cited by 8 publications

(3 citation statements)

References 64 publications

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“…45,46 In the meantime, we have also developed a 3-dimensional (3-D) model of MRGPRX2 using the homology modeling approach as previously published class A human pyroglutamylated RFamide peptide receptor and class B human secretin receptor. 47,48 Because MRGPRX2 is a class A orphan receptor structurally more related to opioid receptors, the 3-D model of MRGPRX2 was built using the k-opioid receptor (PDB ID: 6B73) as a template. 49 Three different homology models were produced by SWISS-MODEL and MODELLER algorithms.…”

Section: Identification Of Mrgprx2 As a Receptor For P17 And 3-dimensional Homology Modeling To Determine Specific Aa Residues Involved Imentioning

confidence: 99%

P17 induces chemotaxis and differentiation of monocytes via MRGPRX2-mediated mast cell–line activation

Duraisamy

Singh

Kumar

et al. 2022

Journal of Allergy and Clinical Immunology

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Background: P17, a peptide isolated from Tetramorium bicarinatum ant venom, is known to induce an alternative phenotype of human monocyte-derived macrophages via activation of an unknown G protein-coupled receptor (GPCR). Objective: We sought to investigate the mechanism of action and the immunomodulatory effects of P17 mediated through MRGPRX2 (Mas-related G protein-coupled receptor X2). Methods: To identify the GPCR for P17, we screened 314 GPCRs. Upon identification of MRGPRX2, a battery of in silico, in vitro, ex vivo, and in vivo assays along with the receptor mutation studies were performed. In particular, to investigate the immunomodulatory actions, we used b-hexosaminidase release assay, cytokine releases, quantification of mRNA expression, cell migration and differentiation assays, immunohistochemical labeling, hematoxylin and eosin, and immunofluorescence staining. Results: P17 activated MRGPRX2 in a dose-dependent manner in b-arrestin recruitment assay. In LAD2 cells, P17 induced calcium and b-hexosaminidase release. Quercetin-and short hairpin RNA-mediated knockdown of MRGPRX2 reduced P17evoked b-hexosaminidase release. In silico and in vitro mutagenesis studies showed that residue Lys 8 of P17 formed a cation-p interaction with the Phe 172 of MRGPRX2 and [Ala 8 ] P17 lost its activity partially. P17 activated LAD2 cells to recruit THP-1 and human monocytes in Transwell migration assay, whereas MRGPRX2-impaired LAD2 cells cannot. In addition, P17-treated LAD2 cells stimulated differentiation of THP-1 and

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Section: Identification Of Mrgprx2 As a Receptor For P17 And 3-dimensional Homology Modeling To Determine Specific Aa Residues Involved Imentioning

confidence: 99%

P17 induces chemotaxis and differentiation of monocytes via MRGPRX2-mediated mast cell–line activation

Duraisamy

Singh

Kumar

et al. 2022

Journal of Allergy and Clinical Immunology

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“…The cell culture and transfection experiment was carried out as per the standardized protocol in our lab [51,52]. Briefly, minimum essential media (Invitrogen Life Technologies Limited, Hong Kong, China) augmented with 10% fetal bovine serum (Invitrogen), 100 U/mL Penicillin along with 100 µg/mL streptomycin (Invitrogen) was utilized to culture the CHO-K1 cells, obtained from American Type Culture Collections (Manassas, VA, USA).…”

Section: Methodsmentioning

confidence: 99%

Glycyrrhizic Acid Reduces Heart Rate and Blood Pressure by a Dual Mechanism

et al. 2016

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Beta adrenergic receptors are crucial for their role in rhythmic contraction of heart along with their role in the pathological conditions such as tachycardia and high risk of heart failure. Studies report that the levels of beta-1 adrenergic receptor tend to decrease by 50%, whereas, the levels of beta-2 adrenergic receptor remains constant during the risk of heart failure. Beta blockers-the antagonistic molecules for beta-adrenergic receptors, function by slowing the heart rate, which thereby allows the left ventricle to fill completely during tachycardia incidents and hence helps in blood pumping capacity of heart and reducing the risk of heart failure. In the present study, we investigate the potential of glycyrrhizic acid (GA) as a possible principal drug molecule for cardiac arrhythmias owing to its ability to induce reduction in the heart rate and blood pressure. We use in vitro and in silico approach to study GA s effect on beta adrenergic receptor along with an in vivo study to examine its effect on heart rate and blood pressure. Additionally, we explore GA s proficiency in eliciting an increase in the plasma levels of vasoactive intestinal peptide, which by dilating the blood vessel consequently, can be a crucial aid during the occurrence of a potential heart attack. Therefore, we propose GA as a potential principal drug molecule via its potential in modulating heart rate and blood pressure.

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“…However, to date, no ligands other than secretin peptide and closely related analogs have been identified to interact with SCTRs. [9][10][11] Beyond that, synthetic Sec-FL represents the only clinically utilized SCTR ligand for diagnostic purposes. 12,13 This might be due to the practical clinical limitations of Sec-FL, such as its short half-life (~2-4 min) and the need for intravenous administration.…”

Section: Introductionmentioning

confidence: 99%

Development of a Testing Funnel for Identification of Small-Molecule Modulators Targeting Secretin Receptors

et al. 2021

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The secretin receptor (SCTR), a prototypical class B G protein-coupled receptor (GPCR), exerts its effects mainly by activating Gαs proteins upon binding of its endogenous peptide ligand secretin. SCTRs can be found in a variety of tissues and organs across species, including the pancreas, stomach, liver, heart, lung, colon, kidney, and brain. Beyond that, modulation of SCTR-mediated signaling has therapeutic potential for the treatment of multiple diseases, such as heart failure, obesity, and diabetes. However, no ligands other than secretin and its peptide analogs have been described to regulate SCTRs, probably due to inherent challenges in family B GPCR drug discovery. Here we report creation of a testing funnel that allowed targeted detection of SCTR small-molecule activators. Pursuing the strategy to identify positive allosteric modulators (PAMs), we established a unique primary screening assay employing a mixture of three orthosteric stimulators that was compared in a screening campaign testing 12,000 small-molecule compounds. Beyond that, we developed a comprehensive set of secondary assays, such as a radiolabel-free target engagement assay and a NanoBiT (NanoLuc Binary Technology)-based approach to detect β-arrestin-2 recruitment, all feasible in a high-throughput environment as well as capable of profiling ligands and hits regarding their effect on binding and receptor function. This combination of methods enabled the discovery of five promising scaffolds, four of which have been validated and further characterized with respect to their allosteric activities. We propose that our results may serve as starting points for developing the first in vivo active small molecules targeting SCTRs.

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Structure-Activity Relationship Studies of N- and C-Terminally Modified Secretin Analogs for the Human Secretin Receptor

Cited by 8 publications

References 64 publications

P17 induces chemotaxis and differentiation of monocytes via MRGPRX2-mediated mast cell–line activation

P17 induces chemotaxis and differentiation of monocytes via MRGPRX2-mediated mast cell–line activation

Glycyrrhizic Acid Reduces Heart Rate and Blood Pressure by a Dual Mechanism

Development of a Testing Funnel for Identification of Small-Molecule Modulators Targeting Secretin Receptors

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