Biochemistry and Pharmacology - Research Publications

Permanent URI for this collection

Search Results

Now showing 1 - 10 of 94
  • Item
    Thumbnail Image
    Relationship of circulating Plasmodium falciparum lifecycle stage to circulating parasitemia and total parasite biomass
    Duffy, MF ; Tonkin-Hill, GQ ; Trianty, L ; Noviyanti, R ; Nguyen, HHT ; Rambhatla, JS ; McConville, MJ ; Rogerson, SJ ; Brown, GV ; Price, RN ; Anstey, NM ; Day, KP ; Papenfuss, AT (NATURE PORTFOLIO, 2022-09-23)
  • Item
    Thumbnail Image
    Microbial Metabolites in the Maturation and Activation of Dendritic Cells and Their Relevance for Respiratory Immunity.
    Wilson, KR ; Gressier, E ; McConville, MJ ; Bedoui, S (Frontiers Media SA, 2022)
    The respiratory tract is a gateway for viruses and bacteria from the external environment to invade the human body. Critical to the protection against these invaders are dendritic cells (DCs) - a group of highly specialized myeloid cells that monitors the lung microenvironment and relays contextual and antigenic information to T cells. Following the recognition of danger signals and/or pathogen molecular associated patterns in the lungs, DCs undergo activation. This process arms DCs with the unique ability to induce the proliferation and differentiation of T cells responding to matching antigen in complex with MHC molecules. Depending on how DCs interact with T cells, the ensuing T cell response can be tolerogenic or immunogenic and as such, the susceptibility and severity of respiratory infections is influenced by the signals DCs receive, integrate, and then convey to T cells. It is becoming increasingly clear that these facets of DC biology are heavily influenced by the cellular components and metabolites produced by the lung and gut microbiota. In this review, we discuss the roles of different DC subsets in respiratory infections and outline how microbial metabolites impact the development, propensity for activation and subsequent activation of DCs. In particular, we highlight these concepts in the context of respiratory immunity.
  • Item
    Thumbnail Image
    Tetraspanin CD82 restrains phagocyte migration but supports macrophage activation
    McGowan, ENS ; Wong, O ; Jones, E ; Nguyen, J ; Wee, J ; Demaria, MC ; Deliyanti, D ; Johnson, CJ ; Hickey, MJ ; McConville, MJ ; Wilkinson-Berka, JL ; Wright, MD ; Binger, KJ (CELL PRESS, 2022-07-15)
    Phagocytes migrate into tissues to combat infection and maintain tissue homeostasis. As dysregulated phagocyte migration and function can lead to inflammation or susceptibility to infection, identifying molecules that control these processes is critical. Here, we show that the tetraspanin CD82 restrains the migration of neutrophils and macrophages into tissues. Cd82 -/- phagocytes exhibited excessive migration during in vivo models of peritoneal inflammation, superfusion of CXCL1, retinopathy of prematurity, and infection with the protozoan parasite L. mexicana. However, with the latter, while Cd82 -/- macrophages infiltrated infection sites at higher proportions, cutaneous L. mexicana lesions were larger and persisted, indicating a failure to control infection. Analyses of in vitro bone-marrow-derived macrophages showed CD82 deficiency altered cellular morphology, and impaired gene expression and metabolism in response to anti-inflammatory activation. Altogether, this work reveals an important role for CD82 in restraining phagocyte infiltration and mediating their differentiation in response to stimulatory cues.
  • Item
    Thumbnail Image
    Oxidative desulfurization pathway for complete catabolism of sulfoquinovose by bacteria
    Sharma, M ; Lingford, JP ; Petricevic, M ; Snow, AJD ; Zhang, Y ; Jarva, MA ; Mui, JW-Y ; Scott, NE ; Saunders, EC ; Epa, R ; da Silva, BM ; Pires, DEV ; Ascher, DB ; McConville, MJ ; Davies, GJ ; Williams, SJ ; Goddard-Borger, ED (NATL ACAD SCIENCES, 2022-01-25)
    Catabolism of sulfoquinovose (SQ; 6-deoxy-6-sulfoglucose), the ubiquitous sulfosugar produced by photosynthetic organisms, is an important component of the biogeochemical carbon and sulfur cycles. Here, we describe a pathway for SQ degradation that involves oxidative desulfurization to release sulfite and enable utilization of the entire carbon skeleton of the sugar to support the growth of the plant pathogen Agrobacterium tumefaciens SQ or its glycoside sulfoquinovosyl glycerol are imported into the cell by an ATP-binding cassette transporter system with an associated SQ binding protein. A sulfoquinovosidase hydrolyzes the SQ glycoside and the liberated SQ is acted on by a flavin mononucleotide-dependent sulfoquinovose monooxygenase, in concert with an NADH-dependent flavin reductase, to release sulfite and 6-oxo-glucose. An NAD(P)H-dependent oxidoreductase reduces the 6-oxo-glucose to glucose, enabling entry into primary metabolic pathways. Structural and biochemical studies provide detailed insights into the recognition of key metabolites by proteins in this pathway. Bioinformatic analyses reveal that the sulfoquinovose monooxygenase pathway is distributed across Alpha- and Betaproteobacteria and is especially prevalent within the Rhizobiales order. This strategy for SQ catabolism is distinct from previously described pathways because it enables the complete utilization of all carbons within SQ by a single organism with concomitant production of inorganic sulfite.
  • Item
    Thumbnail Image
    Toxoplasma gondii apicoplast-resident ferredoxin is an essential electron transfer protein for the MEP isoprenoid-biosynthetic pathway
    Henkel, S ; Frohnecke, N ; Maus, D ; McConville, MJ ; Laue, M ; Blume, M ; Seeber, F (ELSEVIER, 2022-01-01)
    Apicomplexan parasites, such as Toxoplasma gondii, are unusual in that each cell contains a single apicoplast, a plastid-like organelle that compartmentalizes enzymes involved in the essential 2C-methyl-D-erythritol 4-phosphate pathway of isoprenoid biosynthesis. The last two enzymatic steps in this organellar pathway require electrons from a redox carrier. However, the small iron-sulfur cluster-containing protein ferredoxin, a likely candidate for this function, has not been investigated in this context. We show here that inducible knockdown of T. gondii ferredoxin results in progressive inhibition of growth and eventual parasite death. Surprisingly, this phenotype is not accompanied by ultrastructural changes in the apicoplast or overall cell morphology. The knockdown of ferredoxin was instead associated with a dramatic decrease in cellular levels of the last two metabolites in isoprenoid biosynthesis, 1-hydroxy-2-methyl-2-(E)- butenyl-4-pyrophosphate, and isomeric dimethylallyl pyrophosphate/isopentenyl pyrophosphate. Ferredoxin depletion was also observed to impair gliding motility, consistent with isoprenoid metabolites being important for dolichol biosynthesis, protein prenylation, and modification of other proteins involved in motility. Significantly, pharmacological inhibition of isoprenoid synthesis of the host cell exacerbated the impact of ferredoxin depletion on parasite replication, suggesting that the slow onset of parasite death after ferredoxin depletion is because of isoprenoid scavenging from the host cell and leading to partial compensation of the depleted parasite metabolites upon ferredoxin knockdown. Overall, these findings show that ferredoxin has an essential physiological function as an electron donor for the 2C-methyl-D-erythritol 4-phosphate pathway and is a potential drug target for apicomplexan parasites.
  • Item
    Thumbnail Image
    Identification of novel lipid modifications and intermembrane dynamics in Corynebacterium glutamicum using high-resolution mass spectrometry
    Klatt, S ; Brammananth, R ; O'Callaghan, S ; Kouremenos, KA ; Tull, D ; Crellin, PK ; Coppel, RL ; McConville, MJ (ELSEVIER, 2018-07-01)
    The complex cell envelopes of Corynebacterineae contribute to the virulence of pathogenic species (such as Mycobacterium tuberculosis and Corynebacterium diphtheriae) and capacity of nonpathogenic species (such as Corynebacterium glutamicum) to grow in diverse niches. The Corynebacterineae cell envelope comprises an asymmetric outer membrane that overlays the arabinogalactan-peptidoglycan complex and the inner cell membrane. Dissection of the lipid composition of the inner and outer membrane fractions is important for understanding the biogenesis of this multilaminate wall structure. Here, we have undertaken the first high-resolution analysis of C. glutamicum inner and outer membrane lipids. We identified 28 lipid (sub)classes (>233 molecular species), including new subclasses of acylated/acetylated trehalose mono/dicorynomycolic acids, using high-resolution LC/MS/MS coupled with mass spectral library searches in MS-DIAL. All lipid subclasses exhibited polarized distributions across the inner and outer membrane fractions generated by differential solvent extraction. Strikingly, deletion of the TmaT protein, which is required for transport of trehalose corynomycolates across the inner membrane, led to the accumulation of triacylglycerols in the inner membrane and to suppressed synthesis of phosphatidylglycerol and alanylated lipids. These analyses indicate unanticipated connectivity in the synthesis and/or transport of different lipid classes in C. glutamicum.
  • Item
    Thumbnail Image
    MmpA, a Conserved Membrane Protein Required for Efficient Surface Transport of Trehalose Lipids in Corynebacterineae
    Cashmore, TJ ; Klatt, S ; Brammananth, R ; Rainczuk, AK ; Crellin, PK ; McConville, MJ ; Coppel, RL (MDPI, 2021-12-01)
    Cell walls of bacteria of the genera Mycobacterium and Corynebacterium contain high levels of (coryno)mycolic acids. These very long chain fatty acids are synthesized on the cytoplasmic leaflet of the inner membrane (IM) prior to conjugation to the disaccharide, trehalose, and transport to the periplasm. Recent studies on Corynebacterium glutamicum have shown that acetylation of trehalose monohydroxycorynomycolate (hTMCM) promotes its transport across the inner membrane. Acetylation is mediated by the membrane acetyltransferase, TmaT, and is dependent on the presence of a putative methyltransferase, MtrP. Here, we identify a third protein that is required for the acetylation and membrane transport of hTMCM. Deletion of the C. glutamicum gene NCgl2761 (Rv0226c in Mycobacterium tuberculosis) abolished synthesis of acetylated hTMCM (AcTMCM), resulting in an accumulation of hTMCM in the inner membrane and reduced synthesis of trehalose dihydroxycorynomycolate (h2TDCM), a major outer membrane glycolipid. Complementation with the NCgl2761 gene, designated here as mmpA, restored the hTMCM:h2TDCM ratio. Comprehensive lipidomic analysis of the ΔtmaT, ΔmtrP and ΔmmpA mutants revealed strikingly similar global changes in overall membrane lipid composition. Our findings suggest that the acetylation and membrane transport of hTMCM is regulated by multiple proteins: MmpA, MtrP and TmaT, and that defects in this process lead to global, potentially compensatory changes in the composition of inner and outer membranes.
  • Item
    Thumbnail Image
    The Redox Homeostasis of Skeletal Muscle Cells Regulates Stage Differentiation of Toxoplasma gondii
    Rahman, MT ; Swierzy, IJ ; Downie, B ; Salinas, G ; Blume, M ; McConville, MJ ; Lueder, CGK (FRONTIERS MEDIA SA, 2021-11-22)
    Toxoplasma gondii is an obligatory intracellular parasite that causes persistent infections in birds and mammals including ~30% of the world's human population. Differentiation from proliferative and metabolically active tachyzoites to largely dormant bradyzoites initiates the chronic phase of infection and occurs predominantly in brain and muscle tissues. Here we used murine skeletal muscle cells (SkMCs) to decipher host cellular factors that favor T. gondii bradyzoite formation in terminally differentiated and syncytial myotubes, but not in proliferating myoblast precursors. Genome-wide transcriptome analyses of T. gondii-infected SkMCs and non-infected controls identified ~6,500 genes which were differentially expressed (DEGs) in myotubes compared to myoblasts, largely irrespective of infection. On the other hand, genes related to central carbohydrate metabolism, to redox homeostasis, and to the Nrf2-dependent stress response pathway were enriched in both infected myoblast precursors and myotubes. Stable isotope-resolved metabolite profiling indicated increased fluxes into the oxidative branch of the pentose phosphate pathway (OxPPP) in infected myoblasts and into the TCA cycle in infected myotubes. High OxPPP activity in infected myoblasts was associated with increased NADPH/NADP+ ratio while myotubes exhibited higher ROS levels and lower expression of anti-oxidants and detoxification enzymes. Pharmacological reduction of ROS levels in SkMCs inhibited bradyzoite differentiation, while increased ROS induced bradyzoite formation. Thus, we identified a novel host cell-dependent mechanism that triggers stage conversion of T. gondii into persistent tissue cysts in its natural host cell type.
  • Item
    Thumbnail Image
    Analysis of Ca2+ mediated signaling regulating Toxoplasma infectivity reveals complex relationships between key molecules
    Stewart, RJ ; Whitehead, L ; Nijagal, B ; Sleebs, BE ; Lessene, G ; McConville, MJ ; Rogers, KL ; Tonkin, CJ (WILEY, 2017-04-01)
    Host cell invasion, exit and parasite dissemination is critical to the pathogenesis of apicomplexan parasites such as Toxoplasma gondii and Plasmodium spp. These processes are regulated by intracellular Ca2+ signaling although the temporal dynamics of Ca2+ fluxes and down-stream second messenger pathways are poorly understood. Here, we use a genetically encoded biosensor, GFP-Calmodulin-M13-6 (GCaMP6), to capture Ca2+ flux in live Toxoplasma and investigate the role of Ca2+ signaling in egress and motility. Our analysis determines how environmental cues and signal activation influence intracellular Ca2+ flux, allowing placement of effector molecules within this pathway. Importantly, we have identified key interrelationships between cGMP and Ca2+ signaling that are required for activation of egress and motility. Furthermore, we extend this analysis to show that the Ca2+ Dependent Protein Kinases-TgCDPK1 and TgCDPK3-play a role in signal quenching before egress. This work highlights the interrelationships of second messenger pathways of Toxoplasma in space and time, which is likely required for pathogenesis of all apicomplexan species.
  • Item
    No Preview Available
    Function of hTim8a in complex IV assembly in neuronal cells provides insight into pathomechanism underlying Mohr-Tranebjaerg syndrome (vol 8, e48828, 2020)
    Kang, Y ; Anderson, AJ ; Jackson, TD ; Palmer, CS ; De Souza, DP ; Fujihara, KM ; Stait, T ; Frazier, AE ; Clemons, NJ ; Tull, D ; Thorburn, DR ; McConville, MJ ; Ryan, MT ; Stroud, DA ; Stojanovski, D (ELIFE SCIENCES PUBLICATIONS LTD, 2020-03-18)