Development of Potent and Selective Agonists for Complement C5a Receptor 1 with In Vivo Activity

Gorman, Declan M.; Li, Xaria X.; Lee, John D.; Fung, J.; Cui, Cedric S.; Lee, Han Siean; Rolfe, Barbara E.; Woodruff, Trent M.; Clark, Richard J.

doi:10.1021/acs.jmedchem.1c01174

Cited by 10 publications

(13 citation statements)

References 55 publications

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“…Additionally, the loss of β-arrestin 2 recruitment in a previous study was shown to be due to L P6 A substitution in BM213. 36 Our results indicated that the distance between position P6 in the agonist and the TM2–ECL1–TM3 or IWI region in C5aR1 contributes to receptor-biased signaling. Therefore, to investigate the biased mechanism by which C5aR1 senses BM213, an additional cryo-EM structure of the BM213-bound C5aR1–G i protein complex was solved at a 2.9 Å resolution (Fig.…”

Section: Resultsmentioning

confidence: 54%

“…To further investigate these findings, we prepared several derivatives of BM213 with modifications at the P7 position. As the original BM213 study reported, conversion of d -alanine to l -alanine at P7 substantially reduced downstream signaling, 36 while another pharmacological analysis suggested increased aromaticity at this position attenuated C5aR1 activity. 39 Our functional assays revealed that the BM213 P7- d I, BM213 P7- d L , and BM213 P7- d F derivatives, which have bulkier side chains at P7, exhibited a moderate influence on the G i protein signaling; meanwhile, C5aR1 stimulated with l -residues at the P7 position markedly impaired the activation efficacy (Supplementary information, Fig.…”

Section: Resultsmentioning

confidence: 93%

“…Octapeptide BM213 was recently demonstrated to be a G protein-biased agonist of C5aR1 and shares a high sequence similarity with the C-terminus of C5a 36 (Fig. 1a ).…”

Section: Resultsmentioning

confidence: 99%

“…This finding is consistent with a previous study in which increased length/bulkiness of the side chain at this position removed the signaling bias. 36 We also replaced smaller aliphatic residues with phenylalanine or pipecolic acid, and BM213 P6-F and BM213 P6-HomoPro demonstrated the same signaling profile as BM213 (Fig. 4f ; Supplementary information, Fig.…”

Section: Resultsmentioning

confidence: 99%

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Mechanism of activation and biased signaling in complement receptor C5aR1

et al. 2023

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The complement system plays an important role in the innate immune response to invading pathogens. The complement fragment C5a is one of its important effector components and exerts diverse physiological functions through activation of the C5a receptor 1 (C5aR1) and associated downstream G protein and β-arrestin signaling pathways. Dysfunction of the C5a-C5aR1 axis is linked to numerous inflammatory and immune-mediated diseases, but the structural basis for activation and biased signaling of C5aR1 remains elusive. Here, we present cryo-electron microscopy structures of the activated wild-type C5aR1–Gi protein complex bound to each of the following: C5a, the hexapeptidic agonist C5apep, and the G protein-biased agonist BM213. The structures reveal the landscape of the C5a–C5aR1 interaction as well as a common motif for the recognition of diverse orthosteric ligands. Moreover, combined with mutagenesis studies and cell-based pharmacological assays, we deciphered a framework for biased signaling using different peptide analogs and provided insight into the activation mechanism of C5aR1 by solving the structure of C5aR1I116A mutant–Gi signaling activation complex induced by C089, which exerts antagonism on wild-type C5aR1. In addition, unusual conformational changes in the intracellular end of transmembrane domain 7 and helix 8 upon agonist binding suggest a differential signal transduction process. Collectively, our study provides mechanistic understanding into the ligand recognition, biased signaling modulation, activation, and Gi protein coupling of C5aR1, which may facilitate the future design of therapeutic agents.

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Section: Resultsmentioning

confidence: 54%

Section: Resultsmentioning

confidence: 93%

“…Octapeptide BM213 was recently demonstrated to be a G protein-biased agonist of C5aR1 and shares a high sequence similarity with the C-terminus of C5a 36 (Fig. 1a ).…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Mechanism of activation and biased signaling in complement receptor C5aR1

et al. 2023

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“…A series of mutagenesis studies, coupled with functional assays, have suggested that binding of C5a with C5aR1 involves an interface between the core region of C5a with the N-terminus and extracellular loop 2 (ECL2) of C5aR1, and a second interface between the carboxyl-terminus of C5a with the extracellular pocket of the receptor [13][14][15][16] . In addition to C5a, several peptide ligands derived from, and modified based on the carboxyl-terminus sequence of C5a, have been described as potent agonists for C5aR1, albeit with relatively lower affinities [16][17][18][19][20][21] . Of these, a hexapeptide referred to as C5a pep is particularly interesting as it behaves as a functionally-biased agonist compared to C5a in terms of transducer-coupling and cellular responses 11 .…”

Section: Introductionmentioning

confidence: 99%

Structural insights into ligand-recognition, activation, and signaling-bias at the complement C5a receptor, C5aR1

Shukla

Saha

Maharana

et al. 2023

Preprint

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Activation of the complement cascade is a critical part of our innate immune response against invading pathogens, and it operates in a concerted fashion with the antibodies and phagocytic cells towards the clearance of pathogens. The complement peptide C5a, generated during the activation of complement cascade, is a potent inflammatory molecule, and increased levels of C5a are implicated in multiple inflammatory disorders including the advanced stages of COVID-19 pathophysiology. The proximal step in C5a-mediated cellular and physiological responses is its interaction with two different seven transmembrane receptors (7TMRs) known as C5aR1 and C5aR2. Despite a large body of functional data on C5a-C5aR1 interaction, direct visualization of their interaction at high-resolution is still lacking, and it represents a significant knowledge gap in our current understanding of complement receptor activation and signaling. Here, we present cryo-EM structures of C5aR1 activated by its natural agonist C5a, and a G-protein-biased synthetic peptide ligand C5apep, in complex with heterotrimeric G-proteins. The C5a-C5aR1 structure reveals the ligand binding interface involving the N-terminus and extracellular loops of the receptor, and we observe that C5a exhibits a significant conformational change upon its interaction with the receptor compared to the basal conformation. On the other hand, the structural details of C5apep-C5aR1 complex provide a molecular basis to rationalize the ability of peptides, designed based on the carboxyl-terminus sequence of C5a, to act as potent agonists of the receptor, and also the mechanism underlying their biased agonism. In addition, these structural snapshots also reveal activation-associated conformational changes in C5aR1 including outward movement of TM6 and a dramatic rotation of helix 8, and the interaction interface for G-protein-coupling. In summary, this study provides previously lacking molecular basis for the complement C5a recognition and activation of C5aR1, and it should facilitate structure-based discovery of novel lead molecules to target C5aR1 in inflammatory disorders.

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Exploration of compounds to inhibit the Panton-Valentine leukocidin of Staphylococcus aureus

Grebe,

Sarkari,

Cherkaoui

et al. 2024

Med Microbiol Immunol

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The Panton-Valentine leukocidin (PVL) of Staphylococcus aureus is associated with necrotizing infections. After binding to complement 5a receptor (C5aR/CD88) and CD45 it causes cytolysis in polymorphonuclear neutrophils (PMNs) as well as inflammasome activation in monocytes. The objective of this study was to test if (ant)agonists of C5aR and CD45 can attenuate the effect of PVL on PMNs and monocytes. We tested the effect of various concentrations of six C5aR (ant)agonists (avacopan, BM213, DF2593A, JPE-1375, PMX205 and W-54011) and one CD45 antagonist (NQ301) to attenuate the cytotoxic effect of PVL on human PMNs and monocytes in vitro. Shifts in the half-maximal effective concentration (EC50) of PVL to achieve a cytotoxic effect on PMNs and modulation of inflammatory cytokine response from monocytes were determined by flow cytometry and IL-1β detection. Pre-treatment of PMNs with avacopan, PMX205 and W-54,011 resulted in 3.6- to 4.3-fold shifts in the EC50 for PVL and were able to suppress IL-1β secretion by human monocytes in the presence of PVL. BM213, DF2593A and NQ301 were unable to change the susceptibility of PMNs towards PVL or reduce inflammasome activation in monocytes. Avacopan, PMX205 and W-54,011 showed protection against PVL-induced cytotoxicity and suppressed IL-1β secretion by monocytes. Clinical studies are needed to prove whether these substances can be used therapeutically as repurposed drugs.

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Development of Potent and Selective Agonists for Complement C5a Receptor 1 with In Vivo Activity

Cited by 10 publications

References 55 publications

Mechanism of activation and biased signaling in complement receptor C5aR1

Mechanism of activation and biased signaling in complement receptor C5aR1

Structural insights into ligand-recognition, activation, and signaling-bias at the complement C5a receptor, C5aR1

Exploration of compounds to inhibit the Panton-Valentine leukocidin of Staphylococcus aureus

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