Biochemistry and Pharmacology - Research Publications

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    Targeting of C-type lectin-like receptor 2 or P2Y12 for the prevention of platelet activation by immunotherapeutic CpG oligodeoxynucleotides: comment
    Flierl, U ; Nero, TL ; Lim, B ; Andrews, RK ; Parker, MW ; Gardiner, EE ; Peter, K (WILEY, 2018-01)
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    The mechanism of GM-CSF inhibition by human GM-CSF auto-antibodies suggests novel therapeutic opportunities
    Dhagat, U ; Hercus, TR ; Broughton, SE ; Nero, TL ; Shing, KSCT ; Barry, EF ; Thomson, CA ; Bryson, S ; Pai, EF ; McClure, BJ ; Schrader, JW ; Lopez, AF ; Parker, MW (TAYLOR & FRANCIS INC, 2018)
    Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor that can stimulate a variety of cells, but its overexpression leads to excessive production and activation of granulocytes and macrophages with many pathogenic effects. This cytokine is a therapeutic target in inflammatory diseases, and several anti-GM-CSF antibodies have advanced to Phase 2 clinical trials in patients with such diseases, e.g., rheumatoid arthritis. GM-CSF is also an essential factor in preventing pulmonary alveolar proteinosis (PAP), a disease associated with GM-CSF malfunction arising most typically through the presence of GM-CSF neutralizing auto-antibodies. Understanding the mechanism of action for neutralizing antibodies that target GM-CSF is important for improving their specificity and affinity as therapeutics and, conversely, in devising strategies to reduce the effects of GM-CSF auto-antibodies in PAP. We have solved the crystal structures of human GM-CSF bound to antigen-binding fragments of two neutralizing antibodies, the human auto-antibody F1 and the mouse monoclonal antibody 4D4. Coordinates and structure factors of the crystal structures of the GM-CSF:F1 Fab and the GM-CSF:4D4 Fab complexes have been deposited in the RCSB Protein Data Bank under the accession numbers 6BFQ and 6BFS, respectively. The structures show that these antibodies bind to mutually exclusive epitopes on GM-CSF; however, both prevent the cytokine from interacting with its alpha receptor subunit and hence prevent receptor activation. Importantly, identification of the F1 epitope together with functional analyses highlighted modifications to GM-CSF that would abolish auto-antibody recognition whilst retaining GM-CSF function. These results provide a framework for developing novel GM-CSF molecules for PAP treatment and for optimizing current anti-GM-CSF antibodies for use in treating inflammatory disorders.
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    A Family of Dual-Activity Glycosyltransferase-Phosphorylases Mediates Mannogen Turnover and Virulence in Leishmania Parasites
    Sernee, MF ; Ralton, JE ; Nero, TL ; Sobala, LF ; Kloehn, J ; Vieira-Lara, MA ; Cobbold, SA ; Stanton, L ; Pires, DEV ; Hanssen, E ; Males, A ; Ward, T ; Bastidas, LM ; van der Peet, PL ; Parker, MW ; Ascher, DB ; Williams, SJ ; Davies, GJ ; McConville, MJ (CELL PRESS, 2019-09-11)
    Parasitic protists belonging to the genus Leishmania synthesize the non-canonical carbohydrate reserve, mannogen, which is composed of β-1,2-mannan oligosaccharides. Here, we identify a class of dual-activity mannosyltransferase/phosphorylases (MTPs) that catalyze both the sugar nucleotide-dependent biosynthesis and phosphorolytic turnover of mannogen. Structural and phylogenic analysis shows that while the MTPs are structurally related to bacterial mannan phosphorylases, they constitute a distinct family of glycosyltransferases (GT108) that have likely been acquired by horizontal gene transfer from gram-positive bacteria. The seven MTPs catalyze the constitutive synthesis and turnover of mannogen. This metabolic rheostat protects obligate intracellular parasite stages from nutrient excess, and is essential for thermotolerance and parasite infectivity in the mammalian host. Our results suggest that the acquisition and expansion of the MTP family in Leishmania increased the metabolic flexibility of these protists and contributed to their capacity to colonize new host niches.
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    Repurposing the selective estrogen receptor modulator bazedoxifene to suppress gastrointestinal cancer growth.
    Thilakasiri, P ; Huynh, J ; Poh, AR ; Tan, CW ; Nero, TL ; Tran, K ; Parslow, AC ; Afshar-Sterle, S ; Baloyan, D ; Hannan, NJ ; Buchert, M ; Scott, AM ; Griffin, MD ; Hollande, F ; Parker, MW ; Putoczki, TL ; Ernst, M ; Chand, AL (EMBO Press, 2019)
    Excessive signaling through gp130, the shared receptor for the interleukin (IL)6 family of cytokines, is a common hallmark in solid malignancies and promotes their progression. Here, we established the in vivo utility of bazedoxifene, a steroid analog clinically approved for the treatment of osteoporosis, to suppress gp130-dependent tumor growth of the gastrointestinal epithelium. Bazedoxifene administration reduced gastric tumor burden in gp130Y757F mice, where tumors arise exclusively through excessive gp130/STAT3 signaling in response to the IL6 family cytokine IL11. Likewise, in mouse models of sporadic colon and intestinal cancers, which arise from oncogenic mutations in the tumor suppressor gene Apc and the associated β-catenin/canonical WNT pathway, bazedoxifene treatment reduces tumor burden. Consistent with the proposed orthogonal tumor-promoting activity of IL11-dependent gp130/STAT3 signaling, tumors of bazedoxifene-treated Apc-mutant mice retain excessive nuclear accumulation of β-catenin and aberrant WNT pathway activation. Likewise, bazedoxifene treatment of human colon cancer cells harboring mutant APC did not reduce aberrant canonical WNT signaling, but suppressed IL11-dependent STAT3 signaling. Our findings provide compelling proof of concept to support the repurposing of bazedoxifene for the treatment of gastrointestinal cancers in which IL11 plays a tumor-promoting role.
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    EPO does not promote interaction between the erythropoietin and beta-common receptors (vol 8, 12457, 2018)
    Shing, KSCT ; Broughton, SE ; Nero, TL ; Gillinder, K ; Ilsley, MD ; Ramshaw, H ; Lopez, AF ; Griffin, MDW ; Parker, MW ; Perkins, AC ; Dhagat, U (NATURE PUBLISHING GROUP, 2019-05-21)
    A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
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    Small Molecule Binding to Alzheimer Risk Factor CD33 Promotes Aβ Phagocytosis
    Miles, LA ; Hermans, SJ ; Crespi, GAN ; Gooi, JH ; Doughty, L ; Nero, TL ; Markulic, J ; Ebneth, A ; Wroblowski, B ; Oehlrich, D ; Trabanco, AA ; Rives, M-L ; Royaux, I ; Hancock, NC ; Parker, MW (CELL PRESS, 2019-09-27)
    Polymorphism in the microglial receptor CD33 gene has been linked to late-onset Alzheimer disease (AD), and reduced expression of the CD33 sialic acid-binding domain confers protection. Thus, CD33 inhibition might be an effective therapy against disease progression. Progress toward discovery of selective CD33 inhibitors has been hampered by the absence of an atomic resolution structure. We report here the crystal structures of CD33 alone and bound to a subtype-selective sialic acid mimetic called P22 and use them to identify key binding residues by site-directed mutagenesis and binding assays to reveal the molecular basis for its selectivity toward sialylated glycoproteins and glycolipids. We show that P22, when presented on microparticles, increases uptake of the toxic AD peptide, amyloid-β (Aβ), into microglial cells. Thus, the sialic acid-binding site on CD33 is a promising pharmacophore for developing therapeutics that promote clearance of the Aβ peptide that is thought to cause AD.
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    EPO does not promote interaction between the erythropoietin and beta-common receptors
    Shing, KSCT ; Broughton, SE ; Nero, TL ; Gillinder, K ; Ilsley, MD ; Ramshaw, H ; Lopez, AF ; Griffin, MDW ; Parker, MW ; Perkins, AC ; Dhagat, U (NATURE PUBLISHING GROUP, 2018-08-20)
    A direct interaction between the erythropoietin (EPOR) and the beta-common (βc) receptors to form an Innate Repair Receptor (IRR) is controversial. On one hand, studies have shown a functional link between EPOR and βc receptor in tissue protection while others have shown no involvement of the βc receptor in tissue repair. To date there is no biophysical evidence to confirm a direct association of the two receptors either in vitro or in vivo. We investigated the existence of an interaction between the extracellular regions of EPOR and the βc receptor in silico and in vitro (either in the presence or absence of EPO or EPO-derived peptide ARA290). Although a possible interaction between EPOR and βc was suggested by our computational and genomic studies, our in vitro biophysical analysis demonstrates that the extracellular regions of the two receptors do not specifically associate. We also explored the involvement of the βc receptor gene (Csf2rb) under anaemic stress conditions and found no requirement for the βc receptor in mice. In light of these studies, we conclude that the extracellular regions of the EPOR and the βc receptor do not directly interact and that the IRR is not involved in anaemic stress.
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    A dual role for the N-terminal domain of the IL-3 receptor in cell signalling
    Broughton, SE ; Hercus, TR ; Nero, TL ; Kan, WL ; Barry, EF ; Dottore, M ; Shing, KSCT ; Morton, CJ ; Dhagat, U ; Hardy, MP ; Wilson, NJ ; Downton, MT ; Schieber, C ; Hughes, TP ; Lopez, AF ; Parker, MW (NATURE PUBLISHING GROUP, 2018-01-26)
    The interleukin-3 (IL-3) receptor is a cell-surface heterodimer that links the haemopoietic, vascular and immune systems and is overexpressed in acute and chronic myeloid leukaemia progenitor cells. It belongs to the type I cytokine receptor family in which the α-subunits consist of two fibronectin III-like domains that bind cytokine, and a third, evolutionarily unrelated and topologically conserved, N-terminal domain (NTD) with unknown function. Here we show by crystallography that, while the NTD of IL3Rα is highly mobile in the presence of IL-3, it becomes surprisingly rigid in the presence of IL-3 K116W. Mutagenesis, biochemical and functional studies show that the NTD of IL3Rα regulates IL-3 binding and signalling and reveal an unexpected role in preventing spontaneous receptor dimerisation. Our work identifies a dual role for the NTD in this cytokine receptor family, protecting against inappropriate signalling and dynamically regulating cytokine receptor binding and function.