Biochemistry and Pharmacology - Research Publications

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    A novel phosphocholine-mimetic inhibits a pro-inflammatory conformational change in C-reactive protein
    Zeller, J ; Shing, KSCT ; Nero, TL ; McFadyen, JD ; Krippner, G ; Bogner, B ; Kreuzaler, S ; Kiefer, J ; Horner, VK ; Braig, D ; Danish, H ; Baratchi, S ; Fricke, M ; Wang, X ; Kather, MG ; Kammerer, B ; Woollard, KJ ; Sharma, P ; Morton, CJ ; Pietersz, G ; Parker, MW ; Peter, K ; Eisenhardt, SU (WILEY, 2023-01-11)
    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 pathogen-defense 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.
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    C-reactive protein, immunothrombosis and venous thromboembolism
    Dix, C ; Zeller, J ; Stevens, H ; Eisenhardt, SU ; Shing, KSCT ; Nero, TL ; Morton, CJ ; Parker, MW ; Peter, K ; McFadyen, JD (FRONTIERS MEDIA SA, 2022-09-13)
    C-reactive protein (CRP) is a member of the highly conserved pentraxin superfamily of proteins and is often used in clinical practice as a marker of infection and inflammation. There is now increasing evidence that CRP is not only a marker of inflammation, but also that destabilized isoforms of CRP possess pro-inflammatory and pro-thrombotic properties. CRP circulates as a functionally inert pentameric form (pCRP), which relaxes its conformation to pCRP* after binding to phosphocholine-enriched membranes and then dissociates to monomeric CRP (mCRP). with the latter two being destabilized isoforms possessing highly pro-inflammatory features. pCRP* and mCRP have significant biological effects in regulating many of the aspects central to pathogenesis of atherothrombosis and venous thromboembolism (VTE), by directly activating platelets and triggering the classical complement pathway. Importantly, it is now well appreciated that VTE is a consequence of thromboinflammation. Accordingly, acute VTE is known to be associated with classical inflammatory responses and elevations of CRP, and indeed VTE risk is elevated in conditions associated with inflammation, such as inflammatory bowel disease, COVID-19 and sepsis. Although the clinical data regarding the utility of CRP as a biomarker in predicting VTE remains modest, and in some cases conflicting, the clinical utility of CRP appears to be improved in subsets of the population such as in predicting VTE recurrence, in cancer-associated thrombosis and in those with COVID-19. Therefore, given the known biological function of CRP in amplifying inflammation and tissue damage, this raises the prospect that CRP may play a role in promoting VTE formation in the context of concurrent inflammation. However, further investigation is required to unravel whether CRP plays a direct role in the pathogenesis of VTE, the utility of which will be in developing novel prophylactic or therapeutic strategies to target thromboinflammation.
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    Transitional changes in the CRP structure lead to the exposure of proinflammatory binding sites
    Braig, D ; Nero, TL ; Koch, H-G ; Kaiser, B ; Wang, X ; Thiele, JR ; Morton, CJ ; Zeller, J ; Kiefer, J ; Potempa, LA ; Mellett, NA ; Miles, LA ; Du, X-J ; Meikle, PJ ; Huber-Lang, M ; Stark, GB ; Parker, MW ; Peter, K ; Eisenhardt, SU (NATURE PUBLISHING GROUP, 2017-01-23)
    C-reactive protein (CRP) concentrations rise in response to tissue injury or infection. Circulating pentameric CRP (pCRP) localizes to damaged tissue where it leads to complement activation and further tissue damage. In-depth knowledge of the pCRP activation mechanism is essential to develop therapeutic strategies to minimize tissue injury. Here we demonstrate that pCRP by binding to cell-derived microvesicles undergoes a structural change without disrupting the pentameric symmetry (pCRP*). pCRP* constitutes the major CRP species in human-inflamed tissue and allows binding of complement factor 1q (C1q) and activation of the classical complement pathway. pCRP*-microvesicle complexes lead to enhanced recruitment of leukocytes to inflamed tissue. A small-molecule inhibitor of pCRP (1,6-bis(phosphocholine)-hexane), which blocks the pCRP-microvesicle interactions, abrogates these proinflammatory effects. Reducing inflammation-mediated tissue injury by therapeutic inhibition might improve the outcome of myocardial infarction, stroke and other inflammatory conditions.