scholarly journals Western-style diet impedes colonization and clearance of gut bacterial pathogens

2020 ◽  
Author(s):  
Andrew T. Gewirtz ◽  
jun Zou ◽  
XU ZHAO ◽  
Juan Noriega
Keyword(s):  
Host Defense ◽  
Pathogenic Bacteria ◽  
Bacterial Pathogens ◽  
Virulence Gene ◽  
Low Grade ◽  
Colonization Resistance ◽  
Virulence Gene Expression ◽  
The Impact ◽  
Low Grade Inflammation ◽  
Colonic Environment

Western-style diet (WSD), which is high in fat and low in fiber, lacks nutrients to support gut microbiota. Consequently, WSD promotes microbiota encroachment and reduces microbiota density, potentially influencing colonization resistance, immune system readiness, and, consequently host defense against pathogenic bacteria. Additionally, the low-nutrient colonic environment resulting from WSD might impact bacterial pathogens. Hence, we examined the impact of WSD on infection and colitis in response to gut bacterial pathogens. Mice fed grain-based chow (GBC), WSD, or various versions thereof, were orally infected with Citrobacter rodentium or C. difficile. Colonization and its consequences, including inflammation and death were monitored. We observed that WSD delayed Citrobacter growth, reduced its virulence gene expression and ameliorated inflammation.  However, while GBC-fed mice uniformly cleared Citrobacter and were impervious to subsequent Citrobacter challenges, most WSD-fed mice remained chronically infected with Citrobacter while those that cleared it were highly prone to re-infection. Such persistent proneness to Citrobacter infection did not reflect reduced immune responsiveness but rather reflected reduced colonization resistance likely from the low microbiota density resulting from WSD feeding. While persistent Citrobacter infection did not cause overt inflammation, it was associated with low-grade inflammation in colon and adipose tissue that was associated with insulin resistance. An analogous pattern was seen in response to C. difficile with WSD resulting in delayed colonization and mortality while enriching WSD with fiber hastened colonization but afforded clearance and survival. Thus, altering microbiota via diet can profoundly impact the course and consequence of infection following exposure to gut bacterial pathogens.

scholarly journals Western-style diet impedes colonization and clearance of Citrobacter rodentium

2021 ◽  
Vol 17 (4) ◽  
pp. e1009497
Author(s):  
Junqing An ◽  
Xu Zhao ◽  
Yanling Wang ◽  
Juan Noriega ◽  
Andrew T. Gewirtz ◽  
...  
Keyword(s):  
Host Defense ◽  
Pathogenic Bacteria ◽  
Short Chain Fatty Acids ◽  
Low Grade ◽  
Microbiota Composition ◽  
Citrobacter Rodentium ◽  
Colonization Resistance ◽  
The Impact ◽  
Low Grade Inflammation ◽  
Gut Pathogen

Western-style diet (WSD), which is high in fat and low in fiber, lacks nutrients to support gut microbiota. Consequently, WSD reduces microbiota density and promotes microbiota encroachment, potentially influencing colonization resistance, immune system readiness, and thus host defense against pathogenic bacteria. Here we examined the impact of WSD on infection and colitis in response to Citrobacter rodentium. We observed that, relative to mice consuming standard rodent grain-based chow (GBC), feeding WSD starkly altered the dynamics of Citrobacter infection, reducing initial colonization and inflammation but frequently resulting in persistent infection that associated with low-grade inflammation and insulin resistance. WSD’s reduction in initial Citrobacter virulence appeared to reflect that colons of GBC-fed mice contain microbiota metabolites, including short-chain fatty acids, especially acetate, that drive Citrobacter growth and virulence. Citrobacter persistence in WSD-fed mice reflected inability of resident microbiota to out-compete it from the gut lumen, likely reflecting the profound impacts of WSD on microbiota composition. These studies demonstrate potential of altering microbiota and their metabolites by diet to impact the course and consequence of infection following exposure to a gut pathogen.

scholarly journals Consumption of Select Dietary Emulsifiers Exacerbates the Development of Spontaneous Intestinal Adenoma

2021 ◽  
Vol 22 (5) ◽  
pp. 2602
Author(s):  
Emilie Viennois ◽  
Benoit Chassaing
Keyword(s):  
Intestinal Inflammation ◽  
Tumor Development ◽  
Low Grade ◽  
Gastrointestinal Cancers ◽  
Cancer Initiation ◽  
And Function ◽  
The Impact ◽  
Chronic Intestinal Inflammation ◽  
Low Grade Inflammation ◽  
Intestinal Adenoma

Inflammation is a well-characterized critical driver of gastrointestinal cancers. Previous findings have shown that intestinal low-grade inflammation can be promoted by the consumption of select dietary emulsifiers, ubiquitous component of processed foods which alter the composition and function of the gut microbiota. Using a model of colitis-associated cancer, we previously reported that consumption of the dietary emulsifiers carboxymethylcellulose or polysorbate-80 exacerbated colonic tumor development. Here, we investigate the impact of dietary emulsifiers consumption on cancer initiation and progression in a genetical model of intestinal adenomas. In APCmin mice, we observed that dietary emulsifiers consumption enhanced small-intestine tumor development in a way that appeared to be independent of chronic intestinal inflammation but rather associated with emulsifiers’ impact on the proliferative status of the intestinal epithelium as well as on intestinal microbiota composition in both male and female mice. Overall, our findings further support the hypothesis that emulsifier consumption may be a new modifiable risk factor for colorectal cancer (CRC) and that alterations in host–microbiota interactions can favor gastrointestinal carcinogenesis in individuals with a genetical predisposition to such disorders.

Abstract 14849: Gender Differences in Impact of CYP2C19 Polymorphism and Low Grade Inflammation on Coronary Spasm in Patients with Vasospastic Angina (VSA)

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Tomonori Akasaka ◽  
Seiji Hokimoto ◽  
Noriaki Tabata ◽  
Kenji Sakamoto ◽  
Kenichi Tsujita ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Coronary Artery Spasm ◽  
Coronary Spasm ◽  
Control Group ◽  
Low Grade ◽  
Cyp2c19 Genotype ◽  
Loss Of Function ◽  
Hs Crp ◽  
The Impact ◽  
Low Grade Inflammation

Background: Several cytochrome P450 (CYP) enzyme families have been identified in extra hepatic tissues such as heart, vasculature, kidney, and lung. CYP2C19 localized in vascular smooth muscle and endothelium contributes to the regulation of vascular tone and homeostasis. However, it is unknown whether CYP2C19 genotype is associated with the vascular tonus in patients with VSA. The aim of this study was to examine the impact of CYP2C19 genotype on coronary artery spasm in patients with VSA. Methods: We examined the distribution of CYP2C19 genotype in patients with VSA (n=129) who were diagnosed by intra-coronary acetylcholine infusion test and healthy subjects (n=455) as control group. CYP2C19 genotypes were divided into 3 groups; (1) CYP2C19*1/*1: EM, (2) one loss-of-function allele (*1/*2, *1/*3: IM), and (3) two loss-of-function alleles (*2/*2, *2/*3, *3/*3: PM). Moreover, we measured the level of high-sensitive CRP (hs-CRP) as a degree of low glade inflammation in each group. Results: The ratios of CYP2C19 genotype (EM, IM, and PM) were 30, 42, and 28% in VSA group, and 32, 49, and 19% in control group. In short, PM frequency was significantly higher in VSA than in control (28% vs 19%, P=0.026). In VSA group, the ratios of CYP2C19 genotype were 36, 44, and 20% in male, and 20, 39, and 41% in female, respectively. Briefly, the PM frequency was significantly higher in female than in male (41% vs 20%, P<0.001). Moreover, the level of hs-CRP was significantly higher in VSA group than in control group (0.17±0.367 vs 0.10.±0.240, P=0.02). When patients were stratified by gender, the level of hs-CRP was significantly higher in VSA group in female (0.11±0.198 vs 0.06±0.105, P=0.031) and male (0.20±0.438 vs 0.12±0.277, P=0.044). Multivariate analysis for coronary spasm indicated high age, hypertension, and high level of hs-CRP as predictive factors among all subjects. PM is a predictive factor for coronary spasm in female group only (OR3.1, 95%RI 1.525-6.317, P=0.002), but not in male (OR0.829, 95%RI 0.453-1.518, P=0.543). Conclusion: The CYP2C19 two loss-of-function alleles (PM) and low grade inflammation may be associated with pathophysiology of coronary artery spasm and the regulation of coronary tonus, especially in female.

Abstract 14862: Gender Differences in Impact of CYP2C19 Polymorphism and Low Grade Inflammation on Coronary Microvascular Disease

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Tomonori Akasaka ◽  
Seiji Hokimoto ◽  
Noriaki Tabata ◽  
Kenji Sakamoto ◽  
Kenichi Tsujita ◽  
...  
Keyword(s):  
Microvascular Disease ◽  
Control Group ◽  
Female Group ◽  
Low Grade ◽  
Cyp2c19 Genotype ◽  
Loss Of Function ◽  
Disease Group ◽  
Hs Crp ◽  
The Impact ◽  
Low Grade Inflammation

Background: Specific CYPs localized in vascular smooth muscle and endothelium contribute to the regulation of vascular tone and homeostasis. CYP2C19 two loss-of-function alleles (PM) were found to be an independent risk factor for diabetic retinopathy, and PM is associated with the coronary spasm especially in female. However, it is unknown whether CYP2C19 genotype is associated with the coronary microvascular disease. The aim was to evaluate the impact of CYP2C19 genotype on coronary microvascular disease. Methods: We examined CYP2C19 genotype in patients with microvascular disease (n=40) who were diagnosed by intra-coronary acetylcholine infusion test and healthy subjects (n=455) as control group. We defined the coronary microvascular disease that have no epicardial spasm and have angina, ischemic ECG changes, reduced coronary blood flow, or inversion of lactic acid level between intra-coronary and coronary sinus. CYP2C19 genotypes were divided into 3 groups; (1) CYP2C19*1/*1: EM, (2) one loss-of-function allele (*1/*2, *1/*3: IM), and (3) two loss-of-function alleles (*2/*2, *2/*3, *3/*3: PM). Results: The ratios of CYP2C19 genotype (EM, IM, and PM) were 33, 35, and 32% in microvascular disease group, and 32, 49, and 19% in control group. In short, PM frequency was significantly higher in microvascular disease group (32%vs19%,P=0.039). In microvascular disease group, the ratios of CYP2C19 genotype (EM, IM, and PM) were 44, 38, and 19% in male, and 25, 33, and 42% in female, respectively. Briefly, the PM frequency was significantly higher in female than in male (42%vs19%,P=0.011). Moreover, the level of hs-CRP was significantly higher in microvascular disease group (0.37±0.908 vs 0.10±0.240, P<0.001). Multivariate analysis for microvascular disease indicated that gender, high age, smoking, hypertension, and the high level of hs-CRP are predictive factors among all subjects. PM is a predictive factor for microvascular disease in female group only (OR3.214, 95%RI 1.286-8.034, P=0.012), but not in male (OR0.909, 95%RI 0.251-3.285, P=0.884). Conclusion: The CYP2C19 two loss-of-function alleles (PM) and low grade inflammation may be associated with pathophysiology of coronary microvascular disease, especially in female.

scholarly journals Use of a Phosphorylation Site Mutant To Identify Distinct Modes of Gene Repression by the Control of Virulence Regulator (CovR) in Streptococcus pyogenes

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Nicola Horstmann ◽  
Pranoti Sahasrabhojane ◽  
Hui Yao ◽  
Xiaoping Su ◽  
Samuel A. Shelburne
Keyword(s):  
Gene Expression ◽  
Streptococcus Pyogenes ◽  
Response Regulator ◽  
Phosphorylation Site ◽  
Virulence Gene ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Superficial Skin ◽  
Virulence Regulator ◽  
The Impact

ABSTRACT Control of the virulence regulator/sensor kinase (CovRS) two-component system (TCS) serves as a model for investigating the impact of signaling pathways on the pathogenesis of Gram-positive bacteria. However, the molecular mechanisms by which CovR, an OmpR/PhoB family response regulator, controls virulence gene expression are poorly defined, partly due to the labile nature of its aspartate phosphorylation site. To better understand the regulatory effect of phosphorylated CovR, we generated the phosphorylation site mutant strain 10870-CovR-D53E, which we predicted to have a constitutive CovR phosphorylation phenotype. Interestingly, this strain showed CovR activity only for a subset of the CovR regulon, which allowed for classification of CovR-influenced genes into D53E-regulated and D53E-nonregulated groups. Inspection of the promoter sequences of genes belonging to each group revealed distinct promoter architectures with respect to the location and number of putative CovR-binding sites. Electrophoretic mobility shift analysis demonstrated that recombinant CovR-D53E protein retains its ability to bind promoter DNA from both CovR-D53E-regulated and -nonregulated groups, implying that factors other than mere DNA binding are crucial for gene regulation. In fact, we found that CovR-D53E is incapable of dimerization, a process thought to be critical to OmpR/PhoB family regulator function. Thus, our global analysis of CovR-D53E indicates dimerization-dependent and dimerization-independent modes of CovR-mediated repression, thereby establishing distinct mechanisms by which this critical regulator coordinates virulence gene expression. IMPORTANCE Streptococcus pyogenes causes a wide variety of diseases, ranging from superficial skin and throat infections to life-threatening invasive infections. To establish these various disease manifestations, Streptococcus pyogenes requires tightly coordinated production of its virulence factor repertoire. Here, the response regulator CovR plays a crucial role. As an OmpR/PhoB family member, CovR is activated by phosphorylation on a conserved aspartate residue, leading to protein dimerization and subsequent binding to operator sites. Our transcriptome analysis using the monomeric phosphorylation mimic mutant CovR-D53E broadens this general notion by revealing dimerization-independent repression of a subset of CovR-regulated genes. Combined with promoter analyses, these data suggest distinct mechanisms of CovR transcriptional control, which allow for differential expression of virulence genes in response to environmental cues.

scholarly journals Nut consumption is inversely associated with both cancer and total mortality in a Mediterranean population: prospective results from the Moli-sani study

2015 ◽  
Vol 114 (5) ◽  
pp. 804-811 ◽  
Author(s):  
Marialaura Bonaccio ◽  
Augusto Di Castelnuovo ◽  
Amalia De Curtis ◽  
Simona Costanzo ◽  
Francesca Bracone ◽  
...  
Keyword(s):  
Total Mortality ◽  
Risk Groups ◽  
Population Based ◽  
Low Grade ◽  
Mediterranean Population ◽  
The Metabolic Syndrome ◽  
Inflammatory Status ◽  
The Impact ◽  
Low Grade Inflammation ◽  
Nut Intake

AbstractNut intake has been associated with reduced inflammatory status and lower risk of CVD and mortality. The aim of this study was to examine the relationship between nut consumption and mortality and the role of inflammation. We conducted a population-based prospective investigation on 19 386 subjects enrolled in the Moli-sani study. Food intake was recorded by the Italian version of the European Project Investigation into Cancer and Nutrition FFQ. C-reactive protein, leucocyte and platelet counts and the neutrophil:lymphocyte ratio were used as biomarkers of low-grade inflammation. Hazard ratios (HR) were calculated using multivariable Cox proportional hazard models. During a median follow-up of 4·3 years, 334 all-cause deaths occurred. As compared with subjects who never ate nuts, rare intake (≤2 times/month) was inversely associated with mortality (multivariable HR=0·68; 95 % CI 0·54, 0·87). At intake ≥8 times/month, a greater protection was observed (HR=0·53; 0·32, 0·90). Nut intake (v. no intake) conveyed a higher protection to individuals poorly adhering to the Mediterranean diet (MD). A significant reduction in cancer deaths (HR=0·64; 95 % CI 0·44, 0·94) was also observed, whereas the impact on CVD deaths was limited to an inverse, but not significant, trend. Biomarkers of low-grade inflammation were reduced in nut consumers but did not account for the association with mortality. In conclusion, nut intake was associated with reduced cancer and total mortality. The protection was stronger in individuals with lower adherence to MD, whereas it was similar in high-risk groups (diabetics, obese, smokers or those with the metabolic syndrome), as compared with low-risk subjects. Inflammation did not explain the observed relationship.

scholarly journals H-NS is a part of a thermally controlled mechanism for bacterial gene regulation

2005 ◽  
Vol 391 (2) ◽  
pp. 203-213 ◽  
Author(s):  
Shusuke Ono ◽  
Martin D. Goldberg ◽  
Tjelvar Olsson ◽  
Diego Esposito ◽  
Jay C. D. Hinton ◽  
...  
Keyword(s):  
Gene Expression ◽  
Thermal Activation ◽  
Pathogenic Bacteria ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Virulence Gene ◽  
Bacterial Gene ◽  
Virulence Gene Expression ◽  
Serovar Typhimurium ◽  
Micro Organisms ◽  
Dna Binding Properties

Temperature is a primary environmental stress to which micro-organisms must be able to adapt and respond rapidly. Whereas some bacteria are restricted to specific niches and have limited abilities to survive changes in their environment, others, such as members of the Enterobacteriaceae, can withstand wide fluctuations in temperature. In addition to regulating cellular physiology, pathogenic bacteria use temperature as a cue for activating virulence gene expression. This work confirms that the nucleoid-associated protein H-NS (histone-like nucleoid structuring protein) is an essential component in thermoregulation of Salmonella. On increasing the temperature from 25 to 37 °C, more than 200 genes from Salmonella enterica serovar Typhimurium showed H-NS-dependent up-regulation. The thermal activation of gene expression is extremely rapid and change in temperature affects the DNA-binding properties of H-NS. The reduction in gene repression brought about by the increase in temperature is concomitant with a conformational change in the protein, resulting in the decrease in size of high-order oligomers and the appearance of increasing concentrations of discrete dimers of H-NS. The present study addresses one of the key complex mechanisms by which H-NS regulates gene expression.

scholarly journals Identification of Novel Thermosensors in Gram-Positive Pathogens

2020 ◽  
Vol 7 ◽  
Author(s):  
Pilar Fernández ◽  
Alejandra Raquel Díaz ◽  
María Florencia Ré ◽  
Lucía Porrini ◽  
Diego de Mendoza ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Response Regulator ◽  
Physiological Mechanism ◽  
Virulence Gene ◽  
Membrane Lipid ◽  
Gram Positive ◽  
Virulence Gene Expression ◽  
Cognate Response Regulator

Temperature is a crucial variable that every living organism, from bacteria to humans, need to sense and respond to in order to adapt and survive. In particular, pathogenic bacteria exploit host-temperature sensing as a cue for triggering virulence gene expression. Here, we have identified and characterized two integral membrane thermosensor histidine kinases (HKs) from Gram-positive pathogens that exhibit high similarity to DesK, the extensively characterized cold sensor histidine kinase from Bacillus subtilis. Through in vivo experiments, we demonstrate that SA1313 from Staphylococcus aureus and BA5598 from Bacillus anthracis, which likely control the expression of putative ATP binding cassette (ABC) transporters, are regulated by environmental temperature. We show here that these HKs can phosphorylate the non-cognate response regulator DesR, partner of DesK, both in vitro and in vivo, inducing in B. subtilis the expression of the des gene upon a cold shock. In addition, we report the characterization of another DesK homolog from B. subtilis, YvfT, also closely associated to an ABC transporter. Although YvfT phosphorylates DesR in vitro, this sensor kinase can only induce des expression in B. subtilis when overexpressed together with its cognate response regulator YvfU. This finding evidences a physiological mechanism to avoid cross talk with DesK after a temperature downshift. Finally, we present data suggesting that the HKs studied in this work appear to monitor different ranges of membrane lipid properties variations to mount adaptive responses upon cooling. Overall, our findings point out that bacteria have evolved sophisticated mechanisms to assure specificity in the response to environmental stimuli. These findings pave the way to understand thermosensing mediated by membrane proteins that could have important roles upon host invasion by bacterial pathogens.

scholarly journals The Gut Microbiota and Irritable Bowel Syndrome: Friend or Foe?

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Uday C. Ghoshal ◽  
Ratnakar Shukla ◽  
Ujjala Ghoshal ◽  
Kok-Ann Gwee ◽  
Siew C. Ng ◽  
...  
Keyword(s):  
Irritable Bowel Syndrome ◽  
Gut Microbiota ◽  
Pathogenic Bacteria ◽  
Bacterial Overgrowth ◽  
Small Intestinal Bacterial Overgrowth ◽  
Low Grade ◽  
Psychosomatic Disease ◽  
Irritable Bowel ◽  
Low Grade Inflammation ◽  
Qualitative Changes

Progress in the understanding of the pathophysiology of irritable bowel syndrome (IBS), once thought to be a purely psychosomatic disease, has advanced considerably and low-grade inflammation and changes in the gut microbiota now feature as potentially important. The human gut harbours a huge microbial ecosystem, which is equipped to perform a variety of functions such as digestion of food, metabolism of drugs, detoxification of toxic compounds, production of essential vitamins, prevention of attachment of pathogenic bacteria to the gut wall, and maintenance of homeostasis in the gastrointestinal tract. A subset of patients with IBS may have a quantitative increase in bacteria in the small bowel (small intestinal bacterial overgrowth). Qualitative changes in gut microbiota have also been associated with IBS. Targeting the gut microbiota using probiotics and antibiotics has emerged as a potentially effective approach to the treatment of this, hitherto enigmatic, functional bowel disorder. The gut microbiota in health, quantitative and qualitative microbiota changes, and therapeutic manipulations targeting the microbiota in patients with IBS are reviewed in this paper.

scholarly journals Short Chain Fatty Acids Modulate the Growth and Virulence of Pathosymbiont Escherichia coli and Host Response

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 462
Author(s):  
Shiying Zhang ◽  
Belgin Dogan ◽  
Cindy Guo ◽  
Deepali Herlekar ◽  
Katrina Stewart ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Virulence Gene ◽  
Short Chain Fatty Acids ◽  
Short Chain ◽  
Host Responses ◽  
Virulence Gene Expression ◽  
E Coli ◽  
The Impact ◽  
Chain Fatty Acids

Short chain fatty acids (SCFA), principally acetate, propionate, and butyrate, are produced by fermentation of dietary fibers by the gut microbiota. SCFA regulate the growth and virulence of enteric pathogens, such as enterohemorrhagic E. coli (EHEC), Klebsiella and Salmonella. We sought to investigate the impact of SCFA on growth and virulence of pathosymbiont E. coli associated with inflammatory bowel disease (IBD) and colorectal cancer (CRC), and their role in regulating host responses to bacterial infection in vitro. We found that under ileal conditions (pH = 7.4; 12 mM total SCFA), SCFA significantly (p < 0.05) potentiate the growth and motility of pathosymbiont E. coli. However, under colonic conditions (pH = 6.5; 65 to 123 mM total SCFA), SCFA significantly (p < 0.05) inhibit growth in a pH dependent fashion (up to 60%), and down-regulate virulence gene expression (e.g., fliC, fimH, htrA, chuA, pks). Functional analysis reveals that colonic SCFA significantly (p < 0.05) inhibit E. coli motility (up to 95%), infectivity (up to 60%), and type 1 fimbria-mediated agglutination (up to 50%). In addition, SCFA significantly (p < 0.05) inhibit the activation of NF-kB, and IL-8 production by epithelial cells. Our findings provide novel insights on the role of the regional chemical microenvironment in regulating the growth and virulence of pathosymbiont E. coli and opportunities for therapeutic intervention.

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