scholarly journals Metagenomic Profiling of Fecal-Derived Bacterial Membrane Vesicles in Crohn’s Disease Patients

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2795
Author(s):  
Nader Kameli ◽  
Heike E. F. Becker ◽  
Tessa Welbers ◽  
Daisy M. A. E. Jonkers ◽  
John Penders ◽  
...  

Background: In the past, many studies suggested a crucial role for dysbiosis of the gut microbiota in the etiology of Crohn’s disease (CD). However, despite being important players in host–bacteria interaction, the role of bacterial membrane vesicles (MV) has been largely overlooked in the pathogenesis of CD. In this study, we addressed the composition of the bacterial and MV composition in fecal samples of CD patients and compared this to the composition in healthy individuals. Methods: Fecal samples from six healthy subjects (HC) in addition to twelve CD patients (six active, six remission) were analyzed in this study. Fecal bacterial membrane vesicles (fMVs) were isolated by a combination of ultrafiltration and size exclusion chromatography. DNA was obtained from the fMV fraction, the pellet of dissolved feces as bacterial DNA (bDNA), or directly from feces as fecal DNA (fDNA). The fMVs were characterized by nanoparticle tracking analysis and cryo-electron microscopy. Amplicon sequencing of 16s rRNA V4 hypervariable gene regions was conducted to assess microbial composition of all fractions. Results: Beta-diversity analysis showed that the microbial community structure of the fMVs was significantly different from the microbial profiles of the fDNA and bDNA. However, no differences were observed in microbial composition between fDNA and bDNA. The microbial richness of fMVs was significantly decreased in CD patients compared to HC, and even lower in active patients. Profiling of fDNA and bDNA demonstrated that Firmicutes was the most dominant phylum in these fractions, while in fMVs Bacteroidetes was dominant. In fMV, several families and genera belonging to Firmicutes and Proteobacteria were significantly altered in CD patients when compared to HC. Conclusion: The microbial alterations of MVs in CD patients particularly in Firmicutes and Proteobacteria suggest a possible role of MVs in host-microbe symbiosis and induction or progression of inflammation in CD pathogenesis. Yet, the exact role for these fMV in the pathogenesis of the disease needs to be elucidated in future studies.

2014 ◽  
Vol 70 (a1) ◽  
pp. C835-C835
Author(s):  
Sarah Sabboobeh ◽  
Bhushan Nagar

The Immunity-Related GTPase Family M protein (IRGM) is involved in regulating cellular autophagy. Cellular knockdown of IRGM was shown to allow RNA viruses to hijack the autophagic immune response. Additionally, recent genetic studies have shown that underexpression of IRGM is associated with the incidence of Crohn's disease and infection by Mycobacterium tuberculosis. IRGM is an interferon-induced GTPase with an evolutionary conserved P-loop. It is an effector of the interferon-gamma pathway, but, unlike its protein family members, is not directly activated by the pathway. Its mechanism of action has been proposed to occur by translocation of IRGM to the mitochondria through recognition of cardiolipin, and affecting mitochondrial fission to induce autophagy. This potential interaction with cardiolipin might indicate the presence of a unique GTPase recognition and activation fold within IRGM. Our goal is to determine the X-ray crystal structure of IRGM in an effort to understand its molecular role in normal and diseased states. Additionally, we seek to test its interaction with and mechanism of recognition to mitochondrial cardiolipin as well as other autophagy-inducing binding partners. Currently, we have managed to express human IRGM in bacterial cells and have purified it to homogeneity using affinity and size-exclusion chromatography. These findings will serve to elucidate the mechanism of action of IRGM. Crucially, we hope to gain an understanding of its contributing role to Crohn's disease and tuberculosis infection at the molecular level, potentially paving the way to structure-based drug design and therapeutic opportunities.


2020 ◽  
Vol 158 (3) ◽  
pp. S21-S22
Author(s):  
Peilin Zhang ◽  
Lawrence Minardi ◽  
J. Todd Kuenstner ◽  
Steve Zekan ◽  
Rusty Kruzelock

2021 ◽  
Vol 27 (Supplement_1) ◽  
pp. S55-S55
Author(s):  
Marcin Sochal ◽  
Piotr Bialasiewicz ◽  
Agata Gabryelska ◽  
Renata Talar-Wojnarowska ◽  
Jakub Fichna ◽  
...  

Abstract Background and aims Serotonin affects intestinal physiology, mood, as well as circadian rhythm. Moreover, serotonin has proinflammatory function. Therefore, the aim of this study was to investigate the role of serotonin in clinical severity of Crohn’s Disease (CD) and its effect on pain and sleep quality. Methods Fifty-nine CD patients (34 in exacerbation and 25 in remission according to the Harvey-Bradshaw Index-HBI) and 25 health control individuals(HC) were recruited. Sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI) and subjective severity of pain by the Visual Analog Scale (VAS). Seventeen patients were treated with anti-TNF-α induction therapy for 14 weeks. Results Serotonin level was higher in CD (145.12ng/mL, IQR:98.14–179.25) compared to HC (87.52ng/mL, IQR:70.04–129.39; p=0.002) and in exacerbation of CD (157.66ng/mL, IQR:111.94–197.64) compared to remission (122.33ng/mL, IQR:83.28–163.67; p=0.029). Serotonin level with cut-off point of 92.45 ng/mL is useful for distinguishing participants with CD from HC (sensitivity: 78%, specificity: 60%, positive predictive value: 82%). Positive correlation between serotonin and HBI (r=0.279, p=0.032) and severity of diarrhoea (r=0.260, p=0.047) were found. Serotonin does not correlate with PSQI (r=0.152, p=0.168), but correlates with presence of sleep fragmentation for example by getting up to use the bathroom (joined 5b-5j PSQI questions; r=0.270, p=0.039). Correlations between serotonin and VAS were also obtained (r=0.220, p=0.045). Moreover, serotonin level significantly decreased after anti-TNF-α therapy (192.35ng/mL, IQR:150.36–225.56 vs. 121.11ng/mL, IQR:91.28–188.87; p=0.006). The study was funded by National Science Centre, Poland (#2018/31/N/NZ5/03715). Conclusions Serotonin level correlates with the severity of CD and decreases after anti-TNF-α therapy. It is associated with sleep fragmentation, which may be caused by diarrhea.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
M. Hornschuh ◽  
E. Wirthgen ◽  
M. Wolfien ◽  
K. P. Singh ◽  
O. Wolkenhauer ◽  
...  

AbstractEpigenetics has become a promising field for finding new biomarkers and improving diagnosis, prognosis, and drug response in inflammatory bowel disease. The number of people suffering from inflammatory bowel diseases, especially Crohn's disease, has increased remarkably. Crohn's disease is assumed to be the result of a complex interplay between genetic susceptibility, environmental factors, and altered intestinal microbiota, leading to dysregulation of the innate and adaptive immune response. While many genetic variants have been identified to be associated with Crohn's disease, less is known about the influence of epigenetics in the pathogenesis of this disease. In this review, we provide an overview of current epigenetic studies in Crohn's disease. In particular, we enable a deeper insight into applied bioanalytical and computational tools, as well as a comprehensive update toward the cell-specific evaluation of DNA methylation and histone modifications.


Author(s):  
Lina Y Alkaissi ◽  
Martin E Winberg ◽  
Stéphanie DS Heil ◽  
Staffan Haapaniemi ◽  
Pär Myrelid ◽  
...  

Abstract Background The first visible signs of Crohn’s disease (CD) are microscopic erosions over the follicle-associated epithelium (FAE). The aim of the study was to investigate the effects of human α-defensin 5 (HD5) on adherent-invasive Escherichia coli LF82 translocation and HD5 secretion after LF82 exposure in an in vitro model of human FAE and in human FAE ex vivo. Methods An in vitro FAE-model was set up by the coculture of Raji B cells and Caco-2-cl1 cells. Ileal FAE from patients with CD and controls were mounted in Ussing chambers. The effect of HD5 on LF82 translocation was studied by LF82 exposure to the cells or tissues with or without incubation with HD5. The HD5 secretion was measured in human FAE exposed to LF82 or Salmonella typhimurium. The HD5 levels were evaluated by immunofluorescence, immunoblotting, and ELISA. Results There was an increased LF82 translocation across the FAE-model compared with Caco-2-cl1 (P < 0.05). Incubation of cell/tissues with HD5 before LF82 exposure reduced bacterial passage in both models. Human FAE showed increased LF82 translocation in CD compared with controls and attenuated passage after incubation with sublethal HD5 in both CD and controls (P < 0.05). LF82 exposure resulted in a lower HD5 secretion in CD FAE compared with controls (P < 0.05), whereas Salmonella exposure caused equal secretion on CD and controls. There were significantly lower HD5 levels in CD tissues compared with controls. Conclusions Sublethal HD5 reduces the ability of LF82 to translocate through FAE. The HD5 is secreted less in CD in response to LF82, despite a normal response to Salmonella. This further implicates the integrated role of antimicrobial factors and barrier function in CD pathogenesis.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Laura Sanchis-Artero ◽  
Juan Francisco Martínez-Blanch ◽  
Sergio Manresa-Vera ◽  
Ernesto Cortés-Castell ◽  
Marina Valls-Gandia ◽  
...  

AbstractIntestinal dysbiosis is key in the onset and development of Crohn’s disease (CD). We evaluated the microbiota changes in CD patients before and after a six-month anti-TNF treatment, comparing these changes with the microbiota of healthy subjects. This prospective multicenter observational study involved 27 CD patients initiating anti-TNF treatment and 16 healthy individuals. Inflammatory activity was determined at baseline, 3 and 6 months, classifying patients into responders and non-responders. Fecal microbiota was analyzed by massive genomic sequencing thought 16S rRNA amplicon sequencing before and after six months of anti-TNF treatment. The CD cohort showed a decrease in genera of the class Clostridia, short-chain fatty acid producers, and an increase in the phylum Proteobacteria (p < 0.01) versus the healthy cohort. After anti-TNF treatment, the phylum Proteobacteria also increased in non-responders versus responders (13/27) (p < 0.005), with the class Clostridia increasing. In addition, alpha diversity increased in responders versus non-responders (p < 0.01), tending towards eubiosis. An association was found (p < 0.001) in the F.prausnitzii/E.coli ratio between responders and non-responders. The F/E ratio was the most accurate biomarker of anti-TNF response (area under the curve 0.87). Thus, anti-TNF treatment allows partial restoration of intestinal microbiota in responders and the F.prausnitzii/E.coli ratio can provide a reliable indicator of response to anti-TNF in CD.


2021 ◽  
Vol 12 (1) ◽  
pp. 56-66
Author(s):  
Toumi Ryma ◽  
Arezki Samer ◽  
Imene Soufli ◽  
Hayet Rafa ◽  
Chafia Touil-Boukoffa

Inflammatory Bowel Disease (IBD) is a term used to describe a group of complex disorders of the gastrointestinal (GI) tract. IBDs include two main forms: Crohn’s Disease (CD) and Ulcerative Colitis (UC), which share similar clinical symptoms but differ in the anatomical distribution of the inflammatory lesions. The etiology of IBDs is undetermined. Several hypotheses suggest that Crohn’s Disease and Ulcerative Colitis result from an abnormal immune response against endogenous flora and luminal antigens in genetically susceptible individuals. While there is no cure for IBDs, most common treatments (medication and surgery) aim to reduce inflammation and help patients to achieve remission. There is growing evidence and focus on the prophylactic and therapeutic potential of probiotics in IBDs. Probiotics are live microorganisms that regulate the mucosal immune system, the gut microbiota and the production of active metabolites such as Short-Chain Fatty Acids (SCFAs). This review will focus on the role of intestinal dysbiosis in the immunopathogenesis of IBDs and understanding the health-promoting effects of probiotics and their metabolites.


2018 ◽  
Vol 315 (1) ◽  
pp. G1-G11 ◽  
Author(s):  
Camille Pochard ◽  
Sabrina Coquenlorge ◽  
Marie Freyssinet ◽  
Philippe Naveilhan ◽  
Arnaud Bourreille ◽  
...  

Gone are the days when enteric glial cells (EGC) were considered merely satellites of enteric neurons. Like their brain counterpart astrocytes, EGC express an impressive number of receptors for neurotransmitters and intercellular messengers, thereby contributing to neuroprotection and to the regulation of neuronal activity. EGC also produce different soluble factors that regulate neighboring cells, among which are intestinal epithelial cells. A better understanding of EGC response to an inflammatory environment, often referred to as enteric glial reactivity, could help define the physiological role of EGC and the importance of this reactivity in maintaining gut functions. In chronic inflammatory disorders of the gut such as Crohn’s disease (CD) and ulcerative colitis, EGC exhibit abnormal phenotypes, and their neighboring cells are dysfunctional; however, it remains unclear whether EGC are only passive bystanders or active players in the pathophysiology of both disorders. The aim of the present study is to review the physiological roles and properties of EGC, their response to inflammation, and their role in the regulation of the intestinal epithelial barrier and to discuss the emerging concept of CD as an enteric gliopathy.


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