scholarly journals Clostridioides difficile exploits toxin-mediated inflammation to alter the host nutritional landscape and exclude competitors from the gut microbiota

2020 ◽  
Author(s):  
Joshua R. Fletcher ◽  
Colleen M. Pike ◽  
Ruth J. Parsons ◽  
Alissa J. Rivera ◽  
Matthew H. Foley ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gut Microbiota ◽  
Pseudomembranous Colitis ◽  
Toxic Megacolon ◽  
Bacterial Pathogen ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Clostridioides Difficile ◽  
The Face

Introductory paragraphClostridioides difficile is a bacterial pathogen that causes a range of clinical disease from mild to moderate diarrhea, pseudomembranous colitis, and toxic megacolon. Typically, C. difficile infections (CDIs) occur after antibiotic treatment, which alters the gut microbiota, decreasing colonization resistance against C. difficile. Disease is mediated by two large toxins and the expression of their genes is induced upon nutrient depletion via the alternative sigma factor TcdR. Using tcdR mutants in two strains of C. difficile, we defined how toxin-induced inflammation alters C. difficile metabolism, tissue gene expression, and the gut microbiota to determine how inflammation by the host may be beneficial to C. difficile. Here we show that C. difficile metabolism is significantly different in the face of inflammation, with changes in many carbohydrate and amino acid uptake and utilization pathways. Host gene expression signatures suggest that degradation of collagen and other components of the extracellular matrix by matrix metalloproteinases is a major source of peptides and amino acids that supports C. difficile growth in vivo. Lastly, the inflammation induced by C. difficile toxin activity alters the gut microbiota, excluding members from the genus Bacteroides that are able to compete against C. difficile for the same essential nutrients released from collagen degradation.

scholarly journals Clostridioides difficile exploits toxin-mediated inflammation to alter the host nutritional landscape and exclude competitors from the gut microbiota

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Joshua R. Fletcher ◽  
Colleen M. Pike ◽  
Ruth J. Parsons ◽  
Alissa J. Rivera ◽  
Matthew H. Foley ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gut Microbiota ◽  
Pseudomembranous Colitis ◽  
Toxic Megacolon ◽  
Bacterial Pathogen ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Clostridioides Difficile ◽  
The Face

AbstractClostridioides difficile is a bacterial pathogen that causes a range of clinical disease from mild to moderate diarrhea, pseudomembranous colitis, and toxic megacolon. Typically, C. difficile infections (CDIs) occur after antibiotic treatment, which alters the gut microbiota, decreasing colonization resistance against C. difficile. Disease is mediated by two large toxins and the expression of their genes is induced upon nutrient depletion via the alternative sigma factor TcdR. Here, we use tcdR mutants in two strains of C. difficile and omics to investigate how toxin-induced inflammation alters C. difficile metabolism, tissue gene expression and the gut microbiota, and to determine how inflammation by the host may be beneficial to C. difficile. We show that C. difficile metabolism is significantly different in the face of inflammation, with changes in many carbohydrate and amino acid uptake and utilization pathways. Host gene expression signatures suggest that degradation of collagen and other components of the extracellular matrix by matrix metalloproteinases is a major source of peptides and amino acids that supports C. difficile growth in vivo. Lastly, the inflammation induced by C. difficile toxin activity alters the gut microbiota, excluding members from the genus Bacteroides that are able to utilize the same essential nutrients released from collagen degradation.

scholarly journals Studies on Aromatic Amino Acid Uptake by Rat Brain in Vivo

1962 ◽  
Vol 237 (3) ◽  
pp. 803-806
Author(s):  
Gordon Guroff ◽  
Sidney Udenfriend
Keyword(s):  
Amino Acid ◽  
Rat Brain ◽  
Aromatic Amino Acid ◽  
Amino Acid Uptake ◽  
Acid Uptake

Somatostatin inhibits insulin-stimulated amino acid uptake into cultured rat myoblasts

1987 ◽  
Vol 114 (4) ◽  
pp. 470-474 ◽  
Author(s):  
G. S. G. Spencer ◽  
D. J. Hill ◽  
G. J. Garssen ◽  
J. P. G. Williams
Keyword(s):  
Amino Acid ◽  
Nutrient Uptake ◽  
Monolayer Culture ◽  
Amino Acid Uptake ◽  
Inhibitory Effect ◽  
Isobutyric Acid ◽  
Acid Uptake ◽  
Newborn Rat ◽  
Amino Isobutyric Acid

Abstract. The effects of somatostatin on the acute metabolic actions of insulin on newborn rat myoblasts in culture has been examined during monolayer culture. Somatostatin significantly inhibited the insulin-stimulated uptake of [3H]leucine and [3H]amino-isobutyric acid into myoblasts but had no effect on basal (unstimulated) uptake of these two substances. The lowest concentration of somatostatin to have a significant effect was 10 μg/l, and this was apparent in all the experiments undertaken. The inhibitory effect of somatostatin was seen at all effective concentrations of insulin used (0.3–1 U/l). These findings lend support to the concept of an endocrine role for somatostatin in vivo and suggest that a peripheral antagonism may exist between circulating insulin and somatostatin on anabolic processes such as nutrient uptake into cells.

Hepatic Amino Acid Uptake Is Decreased in Lactating Rats. In Vivo and In Vitro Studies

1994 ◽  
Vol 124 (11) ◽  
pp. 2163-2171 ◽  
Author(s):  
José García de la Asunción ◽  
Amparo Devesa ◽  
Juan R. Viña ◽  
Teresa Barber
Keyword(s):  
Amino Acid ◽  
Amino Acid Uptake ◽  
In Vitro Studies ◽  
Acid Uptake

scholarly journals Activation of rat liver branched-chain 2-oxo acid dehydrogenase in vivo by glucagon and adrenaline

1985 ◽  
Vol 232 (2) ◽  
pp. 593-597 ◽  
Author(s):  
K P Block ◽  
B W Heywood ◽  
M G Buse ◽  
A E Harper
Keyword(s):  
Cyclic Amp ◽  
Fold Increase ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Acid Dehydrogenase ◽  
Low Protein ◽  
Branched Chain ◽  
Protein Diets ◽  
In Vivo Administration

The activity of liver branched-chain 2-oxo acid dehydrogenase complex was measured in rats fed on low-protein diets and given adrenaline, glucagon, insulin or dibutyryl cyclic AMP in vivo. Administration of glucagon or adrenaline (200 micrograms/100 g body wt.) resulted in a 4-fold increase in the percentage of active complex. As with glucagon and adrenaline, treatment of rats with cyclic AMP (5 mg/100 g body wt.) resulted in marked activation of branched-chain 2-oxo acid dehydrogenase. Insulin administration (1 unit/100 g body wt.) also resulted in activation of enzyme; however, these effects were less than those observed with glucagon and adrenaline. In contrast with the results obtained with low-protein-fed rats, administration of adrenaline (200 micrograms/100 g body wt.) to rats fed with an adequate amount of protein resulted in only a modest (14%) increase in the activity of the complex. The extent to which these hormones activate branched-chain 2-oxo acid dehydrogenase appears to be correlated with their ability to stimulate amino acid uptake into liver.

Lack of effects of hypothermia on cerebral amino acid uptake in vivo

1977 ◽  
Vol 125 (1) ◽  
pp. 187-191 ◽  
Author(s):  
Emirbek Z. Emirbekov ◽  
Henry Sershen ◽  
Abel Lajtha
Keyword(s):  
Amino Acid ◽  
Amino Acid Uptake ◽  
Acid Uptake

Placental amino acid uptake. VI. Regulation by intracellular substrate

1982 ◽  
Vol 243 (1) ◽  
pp. C46-C51 ◽  
Author(s):  
R. B. Steel ◽  
C. H. Smith ◽  
L. K. Kelley
Keyword(s):  
Amino Acid ◽  
Placental Tissue ◽  
Membrane Vesicles ◽  
Amino Acid Uptake ◽  
Maternal Plasma ◽  
Acid Uptake ◽  
L System ◽  
Intracellular Amino Acids ◽  
Human Placental Tissue

Amino acid uptake by human placental tissue is regulated by intracellular amino acids. alpha-Aminoisobutyric acid (AIB) uptake was reduced at intracellular AIB concentrations of 0.8 mM. The magnitude of reduction increased sharply between 1 and 3 mM and reached a maximum of 45% at 5 mM. Suppression was specific to the "A" system. It occurred only when both the amino acid used for preloading and that used as an uptake substrate were active with that system. In the "L" system, facilitation apparently occurs, and in the "ASC" system there is no apparent effect. The system specificity as well as other evidence indicated that suppression is caused by substrate present intracellularly rather than by dilution of extracellular substrate. Suppression was independent of inhibitors of protein synthesis and was not seen in membrane vesicles prepared from preloaded tissue, indicating that intracellular substrate interacts directly with the carrier (transinhibition) rather than altering its synthesis or degradation. The A system transinhibition has the potential to regulate syncytial uptake in vivo and limit variation due to changes in maternal plasma amino acid concentration.

scholarly journals Alanine uptake activates hepatocellular chloride channels

1997 ◽  
Vol 273 (4) ◽  
pp. G849-G853 ◽  
Author(s):  
Steven D. Lidofsky ◽  
Richard M. Roman
Keyword(s):  
Amino Acid ◽  
Mammalian Cells ◽  
Chloride Channels ◽  
Amino Acid Uptake ◽  
Experimental Models ◽  
Cell Swelling ◽  
Acid Uptake ◽  
Adaptive Responses ◽  
Anion Channels

Cells involved in the retrieval and metabolic conversion of amino acids undergo significant increases in size in response to amino acid uptake. The resultant adaptive responses to cell swelling are thought to include increases in membrane K+ and Cl− permeability through activation of volume-sensitive ion channels. This viewpoint is largely based on experimental models of hypotonic swelling, but few mammalian cells experience hypotonic challenge in vivo. Here we have examined volume regulatory responses in a physiological model of cell-swelling alanine uptake in immortalized hepatocytes. Alanine-induced cell swelling was followed by a decrease in cell volume that was temporally associated with an increase in membrane Cl− currents. These currents were dependent both on alanine concentration and Na+, suggesting that currents were stimulated by Na+-coupled alanine uptake. Cl− currents were outwardly rectifying, exhibited an anion permeability sequence of I− > Br− > Cl−, and were inhibited by the Cl− channel blocker 5-nitro-2-(3-phenylpropylamino)benzoic acid, features similar to those reported for a widely distributed class of volume-sensitive anion channels evoked by experimental hypotonic stress. These findings suggest that volume-sensitive anion channels participate in adaptive responses to amino acid uptake and provide such channels with a new physiological context.

scholarly journals Role of LpL (Lipoprotein Lipase) in Macrophage Polarization In Vitro and In Vivo

2019 ◽  
Vol 39 (10) ◽  
pp. 1967-1985 ◽  
Author(s):  
Hye Rim Chang ◽  
Tatjana Josefs ◽  
Diego Scerbo ◽  
Namrata Gumaste ◽  
Yunying Hu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Lipoprotein Lipase ◽  
Lipid Accumulation ◽  
Macrophage Polarization ◽  
Myeloid Cell ◽  
Acid Uptake ◽  
Lipid Uptake ◽  
Very Low Density Lipoproteins

Objective: Fatty acid uptake and oxidation characterize the metabolism of alternatively activated macrophage polarization in vitro, but the in vivo biology is less clear. We assessed the roles of LpL (lipoprotein lipase)-mediated lipid uptake in macrophage polarization in vitro and in several important tissues in vivo. Approach and Results: We created mice with both global and myeloid-cell specific LpL deficiency. LpL deficiency in the presence of VLDL (very low-density lipoproteins) altered gene expression of bone marrow–derived macrophages and led to reduced lipid uptake but an increase in some anti- and some proinflammatory markers. However, LpL deficiency did not alter lipid accumulation or gene expression in circulating monocytes nor did it change the ratio of Ly6C high /Ly6C low . In adipose tissue, less macrophage lipid accumulation was found with global but not myeloid-specific LpL deficiency. Neither deletion affected the expression of inflammatory genes. Global LpL deficiency also reduced the numbers of elicited peritoneal macrophages. Finally, we assessed gene expression in macrophages from atherosclerotic lesions during regression; LpL deficiency did not affect the polarity of plaque macrophages. Conclusions: The phenotypic changes observed in macrophages upon deletion of Lpl in vitro is not mimicked in tissue macrophages.

scholarly journals Noise modulation in retinoic acid signaling sharpens segmental boundaries of gene expression in the embryonic zebrafish hindbrain

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Julian Sosnik ◽  
Likun Zheng ◽  
Christopher V Rackauckas ◽  
Michelle Digman ◽  
Enrico Gratton ◽  
...  
Keyword(s):  
Gene Expression ◽  
Retinoic Acid ◽  
Fluorescence Lifetime Imaging ◽  
Dependent Manner ◽  
Cellular Mechanisms ◽  
Concentration Dependent Manner ◽  
Temporal Noise ◽  
The Face ◽  
Intracellular Binding

Morphogen gradients induce sharply defined domains of gene expression in a concentration-dependent manner, yet how cells interpret these signals in the face of spatial and temporal noise remains unclear. Using fluorescence lifetime imaging microscopy (FLIM) and phasor analysis to measure endogenous retinoic acid (RA) directly in vivo, we have investigated the amplitude of noise in RA signaling, and how modulation of this noise affects patterning of hindbrain segments (rhombomeres) in the zebrafish embryo. We demonstrate that RA forms a noisy gradient during critical stages of hindbrain patterning and that cells use distinct intracellular binding proteins to attenuate noise in RA levels. Increasing noise disrupts sharpening of rhombomere boundaries and proper patterning of the hindbrain. These findings reveal novel cellular mechanisms of noise regulation, which are likely to play important roles in other aspects of physiology and disease.

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