glycogen and Pneumococcal-Infections

Nonencapsulated Streptococcus pneumoniae bacteria are successful colonizers of the human nasopharynx and often possess genes aliB-like ORF 1 and 2 in place of capsule genes. AliB-like ORF 2 binds peptide FPPQSV, found in Prevotella species, resulting in enhanced colonization. How this response is mediated is so far unknown.. Here we show that the peptide increases expression of genes involved in release of host carbohydrates, carbohydrate uptake and carbohydrate metabolism. In particular, the peptide increased expression of 1,5-anhydro-D-fructose reductase, a metabolic enzyme of an alternative starch and glycogen degrading pathway found in many organisms, in both transcriptomic and proteomic data. The peptide enhanced pneumococcal growth giving a competitive advantage to a strain with aliB-like ORF 2, over its mutant lacking the gene. Possession of aliB-like ORF 2 did not affect release of inflammatory cytokine CXCL8 from epithelial cells in culture and the nonencapsulated wild type strain was not able to establish disease or inflammation in an infant rat model of meningitis.. We propose that AliB-like ORF 2 confers an advantage in colonization by enhancing carbohydrate metabolism resulting in a boost in growth. This may explain the widespread presence of aliB-like ORF 2 in the nonencapsulated pneumococcal population in the human nasopharynx.

Topics: Animals; Bacterial Capsules; Bacterial Proteins; Carbohydrate Metabolism; Carrier Proteins; Cell Line; Cytokines; Disease Models, Animal; Epithelial Cells; Gene Expression Regulation, Bacterial; Genes, Bacterial; Glycogen; Humans; Interleukin-8; Lipoproteins; Nasopharynx; Peptides; Pneumococcal Infections; Prevotella; Proteomics; Rats; Rats, Wistar; Starch; Streptococcus pneumoniae; Sugar Alcohol Dehydrogenases; Transcriptome

Fully activated innate immune cells are required for effective responses to infection, but their prompt deactivation and removal are essential for limiting tissue damage. Here, we have identified a critical role for the prolyl hydroxylase enzyme Phd2 in maintaining the balance between appropriate, predominantly neutrophil-mediated pathogen clearance and resolution of the innate immune response. We demonstrate that myeloid-specific loss of Phd2 resulted in an exaggerated inflammatory response to Streptococcus pneumonia, with increases in neutrophil motility, functional capacity, and survival. These enhanced neutrophil responses were dependent upon increases in glycolytic flux and glycogen stores. Systemic administration of a HIF-prolyl hydroxylase inhibitor replicated the Phd2-deficient phenotype of delayed inflammation resolution. Together, these data identify Phd2 as the dominant HIF-hydroxylase in neutrophils under normoxic conditions and link intrinsic regulation of glycolysis and glycogen stores to the resolution of neutrophil-mediated inflammatory responses. These results demonstrate the therapeutic potential of targeting metabolic pathways in the treatment of inflammatory disease.

Topics: Acute Disease; Animals; Bronchoalveolar Lavage; Colitis; Glycogen; Glycolysis; Humans; Hypoxia-Inducible Factor-Proline Dioxygenases; Immunity, Innate; Inflammation; Leukocytes; Lung Injury; Mice; Mice, Inbred C57BL; Neutrophils; Phenotype; Pneumococcal Infections; Signal Transduction

SpuA is a large multimodular cell wall-attached enzyme involved in the degradation of glycogen by the pathogenic bacterium Streptococcus pneumoniae. The deletion of the gene encoding SpuA from the bacterium resulted in a strain with reduced competitiveness in a mouse model of virulence relative to the parent strain, linking the degradation of host-glycogen to the virulence of the bacterium. Through the combined use of X-ray crystallography, small-angle X-ray scattering, and inhibitor binding, the molecular features involved in substrate recognition by this complex protein are revealed. This uniquely illustrates the complexity of the active site, the conformational changes incurred during carbohydrate binding by this protein, and the interaction and cooperation of its composite modules during this process. New insight into the function of this particular pneumococcal virulence factor is provided along with substantial contributions to the nascent framework for understanding the structural and functional interplay between modules in multimodular carbohydrate-active enzymes.

Topics: Animals; Bacterial Proteins; Binding Sites; Cell Line, Tumor; Cell Wall; Crystallography, X-Ray; Glycogen; Glycoside Hydrolases; Humans; Lung; Mice; Mice, Inbred Strains; Models, Molecular; Multiprotein Complexes; Pneumococcal Infections; Protein Binding; Protein Conformation; Recombinant Proteins; Scattering, Small Angle; Streptococcus pneumoniae; Virulence; Virulence Factors

The present study was performed to determine whether alterations in fuel reserves or energy substrate utilization might explain the performance decrements that occur in bacterial infections. Male Fisher-Dunning rats were studied at 24, 48, and 72 h after inoculation with Streptococcus pneumoniae. Rats were either sedentary or subjected to a 2-h swimming session at these three time points (N = 10 in each group). A more than 60% reduction (P less than 0.01) in performance capacity was observed on day 3 of infection compared with that in noninfected controls. This infection in the rat is characterized by fever (P less than 0.01), depression of plasma zinc (P less than 0.01) and free fatty acid (FFA) levels (P less than 0.01), inhibition of the two- to threefold increase in fasting ketonemia, and a decreased (NS) insulin:glucagon ratio, indicating a catabolic state. Glycogen stores were reduced in the heart (47%), liver (43%), and skeletal muscles (39%) but not in the carcass. Superimposed exercise resulted in a further reduction but not depletion of liver, muscle, and carcass glycogen stores, a less pronounced lactic acid accumulation, and a lower oxygen debt. However, plasma FFA and ketone body levels were still maintained or even elevated, suggesting that fat is supplied as fuel during swimming exercise in this infection. Thus, results indicate that unavailability of energy substrates or lactacidosis is not limiting for performance capacity during this severe infection.

Topics: Animals; Body Temperature; Carbohydrate Metabolism; Fatigue; Fatty Acids; Glucagon; Glycogen; Insulin; Lactates; Lactic Acid; Liver; Male; Muscles; Myocardium; Oxygen Consumption; Physical Exertion; Pneumococcal Infections; Rats; Rats, Inbred F344; Zinc

These experiments were designed to study whether endurance training prior to Streptococcus pneumoniae infection in rats (N = 15 in each group) alters lethality, performance capacity, and related energy metabolism. A 5-d.wk-1, 4-wk-long pre-infection training program with gradually increasing swim time caused no protection from lethality (48% at 72 h post-inoculation), but performance capacity increased by 68% (P less than 0.01). The catabolic responses as evidenced by changes in insulin and glucagon levels were less pronounced. Mobilization of free fatty acids increased twofold (P less than 0.01), and improved ketonemic adaptation (47%, P less than 0.01) occurred with concomitant saved carcass, liver, and skeletal muscle glycogen contents (P less than 0.01). This shift from carbohydrate toward fat metabolism during exercise as a result of training was also reflected by 21% lower (P less than 0.01) blood lactate levels. It was concluded that the improved metabolic status, characterizing the trained as compared with the untrained host, is partly preserved during ongoing acute gram-positive bacterial infection.

Topics: Animals; Body Temperature; Carbohydrate Metabolism; Fatigue; Fatty Acids; Glucose; Glycogen; Ketone Bodies; Lactates; Lactic Acid; Liver; Male; Muscles; Myocardium; Physical Conditioning, Animal; Pneumococcal Infections; Rats; Rats, Inbred F344; Zinc

Levels of glucose, insulin, and glucagon in portal vein plasma and of liver glycogen and cyclic AMP and activities of glycogen synthase and phosphorylase in liver were assayed in control (CONT) rats and rats infected (INF) with Diplococcus pneumoniae. In INF rats compared with CONT rats, insulin and glucagon levels were higher (8,12,24 h). Activity of synthase I was lower (8, 12, 24 h) and of phosphorylase higher (12 and 24 h) in INF rats. Cyclic AMP levels were higher in INF rats at 12 and 24 h. Total synthase activity was lower in INF rats at 24 h. Glucose given intravenously increased glycogen less in INF than in CONT rats and activated synthase and inactivated phosphorylase in all animals except at 24 h in INF rats. However, in situ perfusion of the livers at 24 h with glucose in buffer decreased phosphorylase activities in all animals and increased synthase I activities in CONT but not INF rats.

Topics: Animals; Blood Glucose; Body Temperature; Cyclic AMP; Glucagon; Glucose; Glycogen; Glycogen Synthase; Insulin; Liver; Male; Phosphorylases; Pneumococcal Infections; Rats; Streptococcus pneumoniae

Topics: Acetates; Adenosine Diphosphate; Adenosine Triphosphate; Amino Acids; Animals; Carbohydrate Metabolism; Carbon Isotopes; Disease Models, Animal; Glucose; Glycogen; Lactates; Lipid Metabolism; Liver; Liver Glycogen; Lung; Muscles; Myocardium; Penicillin G; Pneumococcal Infections; Proteins; Pyruvates; Rabbits; Sepsis; Streptococcus pneumoniae