scholarly journals A nadA mutation confers nicotinic acid auxotrophy in pro-carcinogenic intestinal Escherichia coli NC101

2021 ◽  
Author(s):  
Lacey R. Lopez ◽  
Cassandra J. Barlogio ◽  
Christopher A. Broberg ◽  
Jeremy Wang ◽  
Janelle C. Arthur

AbstractInflammatory bowel diseases and inflammation-associated colorectal cancer are linked to blooms of adherent-invasive Escherichia coli (AIEC) in the intestinal microbiota. AIEC are functionally defined by their ability to adhere/invade epithelial cells and survive/replicate within macrophages. Changes in micronutrient availability can alter AIEC physiology and interactions with host cells. Thus, culturing AIEC for mechanistic investigations often involves precise nutrient formulation. We observed that the pro-inflammatory and pro-carcinogenic AIEC strain NC101 failed to grow in minimal media (MM). We hypothesized that NC101 was unable to synthesize a vital micronutrient normally found in the host gut. Through nutrient supplementation studies, we identified that NC101 is a nicotinic acid (NA) auxotroph. NA auxotrophy was not observed in the other non-toxigenic E. coli or AIEC strains we tested. Sequencing revealed NC101 has a missense mutation in nadA, a gene encoding quinolinate synthase A that is important for de novo NAD biosynthesis. Correcting the identified nadA point mutation restored NC101 prototrophy without impacting AIEC function, including motility and AIEC-defining survival in macrophages. Our findings, along with the generation of a prototrophic NC101 strain, will greatly enhance the ability to perform in vitro functional studies that are needed for mechanistic investigations on the role of intestinal E. coli in digestive disease.ImportanceInflammatory bowel diseases (IBD) and colorectal cancer (CRC) are significant global health concerns that are influenced by gut resident microbes, like adherent-invasive Escherichia coli (AIEC). Nutrient availability influences specialized metabolite production, AIEC-defining functional attributes, and AIEC:host interactions. NC101 is a pro-inflammatory and pro-carcinogenic AIEC strain commonly used for studies on IBD and CRC. We identified that NC101 growth in vitro requires a micronutrient found in the host gut. By correcting an identified mutation, we generated an NC101 strain that no longer has micronutrient restrictions. Our findings will facilitate future research that necessitates precise nutrient manipulation, enhancing AIEC functional studies and investigations on other auxotrophic intestinal microbiota members. Broadly, this will improve the study of bacterial:host interactions impacting health and disease.

2021 ◽  
Vol 12 ◽  
Author(s):  
Lacey R. Lopez ◽  
Cassandra J. Barlogio ◽  
Christopher A. Broberg ◽  
Jeremy Wang ◽  
Janelle C. Arthur

Inflammatory bowel diseases (IBDs) and inflammation-associated colorectal cancer (CRC) are linked to blooms of adherent-invasive Escherichia coli (AIEC) in the intestinal microbiota. AIEC are functionally defined by their ability to adhere/invade epithelial cells and survive/replicate within macrophages. Changes in micronutrient availability can alter AIEC physiology and interactions with host cells. Thus, culturing AIEC for mechanistic investigations often involves precise nutrient formulation. We observed that the pro-inflammatory and pro-carcinogenic AIEC strain NC101 failed to grow in minimal media (MM). We hypothesized that NC101 was unable to synthesize a vital micronutrient normally found in the host gut. Through nutrient supplementation studies, we identified that NC101 is a nicotinic acid (NA) auxotroph. NA auxotrophy was not observed in the other non-toxigenic E. coli or AIEC strains we tested. Sequencing revealed NC101 has a missense mutation in nadA, a gene encoding quinolinate synthase A that is important for de novo nicotinamide adenine dinucleotide (NAD) biosynthesis. Correcting the identified nadA point mutation restored NC101 prototrophy without impacting AIEC function, including motility and AIEC-defining survival in macrophages. Our findings, along with the generation of a prototrophic NC101 strain, will greatly enhance the ability to perform in vitro functional studies that are needed for mechanistic investigations on the role of intestinal E. coli in digestive disease.


2019 ◽  
Vol 10 (2) ◽  
pp. 1132-1145 ◽  
Author(s):  
Meiling Liu ◽  
Xiuxia Zhang ◽  
Yunpeng Hao ◽  
Jinhua Ding ◽  
Jing Shen ◽  
...  

Multiple articles have confirmed that an imbalance of the intestinal microbiota is closely related to aberrant immune responses of the intestines and to the pathogenesis of inflammatory bowel diseases (IBDs).


2019 ◽  
Vol 20 (11) ◽  
pp. 2752 ◽  
Author(s):  
Motomichi Fujita ◽  
Yuka Ito-Fujita ◽  
Takuya Iyoda ◽  
Manabu Sasada ◽  
Yuko Okada ◽  
...  

Inflammatory bowel diseases increase the risk of colorectal cancer and colitis-associated colorectal cancer (CAC). Tenascin-C, a matricellular protein, is highly expressed in inflammatory bowel diseases, especially colorectal cancer. However, the role of tenascin-C in the development of CAC is not yet fully understood. We previously showed that a peptide derived from tenascin-C, peptide TNIIIA2, induces potent and sustained activation of β1-integrin. Moreover, we recently reported that peptide TNIIIA2 promotes invasion and metastasis in colon cancer cells. Here, we show the pathological relevance of TNIIIA2-related functional site for the development of CAC. First, expression of the TNIIIA2-containing TNC peptides/fragments was detected in dysplastic lesions of an azoxymethane/dextran sodium sulfate (AOM/DSS) mouse model. In vitro experiments demonstrated that conditioned medium from peptide TNIIIA2-stimulated human WI-38 fibroblasts induced malignant transformation in preneoplastic epithelial HaCaT cells. Indeed, these pro-proliferative effects stimulated by peptide TNIIIA2 were abrogated by peptide FNIII14, which has the ability to inactivate β1-integrin. Importantly, peptide FNIII14 was capable of suppressing polyp formation in the AOM/DSS model. Therefore, tenascin-C-derived peptide TNIIIA2 may contribute to the formation of CAC via activation of stromal fibroblasts based on β1-integrin activation. Peptide FNIII14 could represent a potential prophylactic treatment for CAC.


2014 ◽  
Vol 73 (4) ◽  
pp. 490-497 ◽  
Author(s):  
Kristin A. Verbeke ◽  
Leen Boesmans ◽  
Eef Boets

Crohn's disease (CD) and ulcerative colitis (UC) are the two major phenotypes of inflammatory bowel diseases (IBD) which constitute a spectrum of chronic, debilitating diseases characterised by a relapsing inflammation of the intestinal mucosal lining. Evidence from a variety of disciplines implicates the intestinal microbiota in the pathogenesis of idiopathic IBD and their complications, including pouchitis. Many studies have reported a dysbiosis in IBD, characterised by a decrease in diversity, a decreased abundance of some dominant commensal members (such asClostridiumIV and XIVa) and an increase in detrimental bacteria (such as sulphate reducing bacteria andEscherichia coli). Therapies such as prebiotics and probiotics aim to selectively manipulate the intestinal microbiota and have been evaluated as an attractive therapeutic option with few side effects. The multispecies product VSL#3 was found effective in preventing and maintaining remission in pouchitis, whereas both VSL#3 andE. coliNissle were effective in maintaining remission in UC. A more drastic approach to restore the composition of the microbiota and correct the underlying imbalance is a faecal microbiota transplantation (FMT). FMT has been successfully applied to treat patients with even recalcitrantClostridium difficileinfection. Particularly in UC, the majority of studies suggest that FMT may be an effective treatment option although the evidence is still limited. It is anticipated that our increasing knowledge on the composition and function of the intestinal microbiota components will allow in the future for a better selection of highly performing bacteria with specific functions required for specific benefits.


Cancers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 2361
Author(s):  
Filippo Vernia ◽  
Marco Valvano ◽  
Stefano Fabiani ◽  
Gianpiero Stefanelli ◽  
Salvatore Longo ◽  
...  

Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the Western world. Early detection decreases incidence and mortality. Screening programs based on fecal occult blood testing help identify patients requiring endoscopic examination, but accuracy is far from optimal. Among the alternative strategies, volatile organic compounds (VOCs) represent novel potentially useful biomarkers of colorectal cancer. They also represent a promising tool for the screening of both intestinal inflammation and related CRC. The review is focused on the diagnostic potential of VOCs in sporadic CRC and in inflammatory bowel diseases (IBD), which increase the risk of CRC, analyzing future clinical applications. Despite limitations related to inadequate strength of evidence, differing analytical platforms identify different VOCs, and this unconventional approach for diagnosing colorectal cancer is promising. Some VOC profiles, besides identifying inflammation, seem disease-specific in inflammatory bowel diseases. Thus, breath, urine, and fecal VOCs provide a new and promising clinical approach to differential diagnosis, evaluation of the inflammatory status, and possibly the assessment of treatment efficacy in IBD. Conversely, specific VOC patterns correlating inflammatory bowel disease and cancer risk are still lacking, and studies focused on this issue are strongly encouraged. No prospective studies have assessed the risk of CRC development by using VOCs in samples collected before the onset of disease, both in the general population and in patients with IBD.


2016 ◽  
Vol 7 (10) ◽  
pp. 4388-4399 ◽  
Author(s):  
Anouk Kaulmann ◽  
Sébastien Planchon ◽  
Jenny Renaut ◽  
Yves-Jacques Schneider ◽  
Lucien Hoffmann ◽  
...  

Proteomic response of intestinal cells as a model of inflammatory bowel diseases to digested plum and cabbage rich in polyphenols and carotenoids.


Nutrients ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 3402
Author(s):  
Barbara Borsani ◽  
Raffaella De Santis ◽  
Veronica Perico ◽  
Francesca Penagini ◽  
Erica Pendezza ◽  
...  

Carrageenan (CGN) is a high molecular weight polysaccharide extracted from red seaweeds, composed of D-galactose residues linked in β-1,4 and α-1,3 galactose-galactose bond, widely used as a food additive in processed foods for its properties as a thickener, gelling agent, emulsifier, and stabilizer. In recent years, with the spread of the Western diet (WD), its consumption has increased. Nonetheless, there is a debate on its safety. CGN is extensively used as an inflammatory and adjuvant agent in vitro and in animal experimental models for the investigation of immune processes or to assess the activity of anti-inflammatory drugs. CGN can activate the innate immune pathways of inflammation, alter the gut microbiota composition and the thickness of the mucus barrier. Clinical evidence suggests that CGN is involved in the pathogenesis and clinical management of inflammatory bowel diseases (IBD), indeed food-exclusion diets can be an effective therapy for disease remission. Moreover, specific IgE to the oligosaccharide α-Gal has been associated with allergic reactions commonly referred to as the “α-Gal syndrome”. This review aims to discuss the role of carrageenan in inflammatory bowel diseases and allergic reactions following the current evidence. Furthermore, as no definitive data are available on the safety and the effects of CGN, we suggest gaps to be filled and advise to limit the human exposure to CGN by reducing the consumption of ultra-processed foods.


2020 ◽  
Vol 79 (4) ◽  
pp. 468-478 ◽  
Author(s):  
Stefania Del Fabbro ◽  
Philip C. Calder ◽  
Caroline E. Childs

The aim of the present paper is to review the effects of non-digestible oligosaccharides (NDO) on immunity, focusing on their microbiota-independent mechanisms of action, as well as to explore their potential beneficial role in inflammatory bowel diseases (IBD). IBD are chronic, inflammatory conditions of the gastrointestinal tract. Individuals with IBD have an aberrant immune response to commensal microbiota, resulting in extensive mucosal inflammation and increased intestinal permeability. NDO are prebiotic fibres well known for their role in supporting intestinal health through modulation of the gut microbiota. NDO reach the colon intact and are fermented by commensal bacteria, resulting in the production of SCFA with immunomodulatory properties. In disease states characterised by increased gut permeability, prebiotics may also bypass the gut barrier and directly interact with intestinal and systemic immune cells, as demonstrated in patients with IBD and in infants with an immature gut. In vitro models show that fructooligosaccharides, inulin and galactooligosaccharides exert microbiota-independent effects on immunity by binding to toll-like receptors on monocytes, macrophages and intestinal epithelial cells and by modulating cytokine production and immune cell maturation. Moreover, animal models and human supplementation studies demonstrate that some prebiotics, including inulin and lactulose, might reduce intestinal inflammation and IBD symptoms. Although there are convincing preliminary data to support NDO as immunomodulators in the management of IBD, their mechanisms of action are still unclear and larger standardised studies need to be performed using a wider range of prebiotics.


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