A novel phosphocholine‐mimetic inhibits a pro‐inflammatory conformational change in C‐reactive protein

Abstract

C-reactive protein (CRP) is an early-stage acute phase protein and highly upregulated in response to inflammatory reactions. We recently identified a novel mechanism that leads to a conformational change from the native, functionally relatively inert, pentameric CRP (pCRP) structure to a pentameric CRP intermediate (pCRP*) and ultimately to the monomeric CRP (mCRP) form, both exhibiting highly pro-inflammatory effects. This transition in the inflammatory profile of CRP is mediated by binding of pCRP to activated/damaged cell membranes via exposed phosphocholine lipid head groups. We designed a tool compound as a low molecular weight CRP inhibitor using the structure of phosphocholine as a template. X-ray crystallography revealed specific binding to the phosphocholine binding pockets of pCRP. We provide in vitro and in vivo proof-of-concept data demonstrating that the low molecular weight tool compound inhibits CRP-driven exacerbation of local inflammatory responses, while potentially preserving pathogendefense functions of CRP. The inhibition of the conformational change generating pro-inflammatory CRP isoforms via phosphocholine-mimicking compounds represents a promising, potentially broadly applicable anti-inflammatory therapy.

Targeting conformational changes in C‐reactive protein to inhibit pro‐inflammatory actions

“…In their present study, Zeller et al ( 2022 ) employed a combination of medicinal chemistry and computational modeling to develop a low molecular weight monovalent tool compound C10M [3‐(dibutyl amino) propyl) phosphonic acid]. Using X‐ray crystallography, the authors demonstrate that C10M binds to the PC/PE binding pocket on pCRP and competitively inhibits the binding of pCRP to exposed PC/PE head groups on bioactive lipids and subsequently prevent formation of pCRP*/mCRP (Fig 1 ).…”

“…In summary, Zeller et al ( 2022 ) provide a proof‐of‐concept of selective targeting the actions of CRP. This work will certainly facilitate future investigations into the full spectrum of pCRP's roles in inflammatory pathologies and opens a novel therapeutic avenue to prevent or limit the harmful actions of pCRP.…”

C-reactive protein isoforms as prognostic markers of COVID-19 severity

“…Targeting mCRP in COVID-19 patients could represent a novel therapeutic target. Besides CRP apheresis, approaches aimed at inhibiting either CRP dissociation into mCRP ( 34 , 35 ) or antibodies against mCRP ( 36 ) could represent attractive alternatives to prevent the cytokine storm and hyperinflammatory status associated to COVID-19. Yet, caution should be taken when targeting CRP as the effects of CRP isoforms may differ depending on the infection stage; in early phases of infection CRP acts as a soluble pattern recognition receptor targeting necrotic or damaged tissue, while in late phases of infection, unrestrained levels of CRP may cause hyperinflammation with its subsequent complications.…”

Structural basis for surface activation of the classical complement cascade by the short pentraxin C-reactive protein

“…Calcium dependent aggregation of lipids is a known function of CRP (41, 42), which we postulated to be mediated by a decameric species of CRP (15), whereby two CRP pentamers associate in an offset stack through A-face interactions ( Figs. 1D , E ) (5, 15, 16). By examining structures of decameric CRP in the protein database (PDB; 3PVO, 3PVN, 7TBA and 7PK9) (5, 15, 16), we identified residue Arg188 as the predominant mediator of decamerization, as it forms four ionic bonds per decamer with residues Asp163 or Asp169 on the opposing pentamer ( Fig.…”

“…The A-face of CRP associates with effector ligands such as Fcγ receptors (6,7), which mediate phagocytosis (5). Pentameric CRP can also oligomerise into decamers via A-face stacking (15), which may cause agglutination of cells or cellular debris (5,27). The initiating component of the classical complement pathway, the C1 complex (Fig.…”