101
|
Abstract
Although the gastrointestinal tract is regarded as mainly anoxic, low O2 tension is present in the gut and tends to increase following antibiotic-induced disruption of the host microbiota. Two decreasing O2 gradients are observed, a longitudinal one from the small to the large intestine and a second one from the intestinal epithelium toward the colon lumen. Thus, O2 concentration fluctuations within the gastrointestinal tract are a challenge for anaerobic bacteria such as C. difficile. This enteropathogen has developed efficient strategies to detoxify O2. In this work, we identified reverse rubrerythrins and flavodiiron proteins as key actors for O2 tolerance in C. difficile. These enzymes are responsible for the reduction of O2 protecting C. difficile vegetative cells from associated damages. Original and complex detoxification pathways involving O2-reductases are crucial in the ability of C. difficile to tolerate O2 and survive to O2 concentrations encountered in the gastrointestinal tract. Clostridioides difficile is a major cause of diarrhea associated with antibiotherapy. After germination of C. difficile spores in the small intestine, vegetative cells are exposed to low oxygen (O2) tensions. While considered strictly anaerobic, C. difficile is able to grow in nonstrict anaerobic conditions (1 to 3% O2) and tolerates brief air exposure indicating that this bacterium harbors an arsenal of proteins involved in O2 detoxification and/or protection. Tolerance of C. difficile to low O2 tensions requires the presence of the alternative sigma factor, σB, involved in the general stress response. Among the genes positively controlled by σB, four encode proteins likely involved in O2 detoxification: two flavodiiron proteins (FdpA and FdpF) and two reverse rubrerythrins (revRbr1 and revRbr2). As previously observed for FdpF, we showed that both purified revRbr1 and revRbr2 harbor NADH-linked O2- and H2O2-reductase activities in vitro, while purified FdpA mainly acts as an O2-reductase. The growth of a fdpA mutant is affected at 0.4% O2, while inactivation of both revRbrs leads to a growth defect above 0.1% O2. O2-reductase activities of these different proteins are additive since the quadruple mutant displays a stronger phenotype when exposed to low O2 tensions compared to the triple mutants. Our results demonstrate a key role for revRbrs, FdpF, and FdpA proteins in the ability of C. difficile to grow in the presence of physiological O2 tensions such as those encountered in the colon.
Collapse
|
102
|
Costa MO, Harding JCS. Swine dysentery disease mechanism: Brachyspira hampsonii impairs the colonic immune and epithelial repair responses to induce lesions. Microb Pathog 2020; 148:104470. [PMID: 32889046 DOI: 10.1016/j.micpath.2020.104470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/20/2020] [Accepted: 08/25/2020] [Indexed: 10/23/2022]
Abstract
Swine dysentery (SD) is a global, production-limiting disease of pigs in commercial farms. It is associated with infection by Brachyspira hyodysenteriae and B. hampsonii, and characterized by mucohaemorrhagic diarrhea and colitis, SD prevention, treatment or control relies heavily on antimicrobials as no commercial vaccines are available. This is linked to our poor understanding of the disease pathogenesis. Our goal was to characterize the host-pathogen interactions during the early stage of infection. We employed dual RNA-seq to profile mRNA and miRNA following 1-h incubation of colonic explants with a pathogenic or a non-pathogenic B. hampsonii strain. Our results suggest that the pathogenic strain more efficiently interfered with the host's ability to activate and build a humoral response (through IL-4/CCR6/KLHL6 interactions), epithelial wound repair mechanisms (associated with LSECtin impairment of macrophages), induced mitochondrial dysfunction (linked to MDR1), and loss of microbiome homeostasis. The pathogenic strain also up-regulated the expression of stress-associated genes, when compared to the non-pathogenic strain. These results shed a light on the pathophysiological mechanisms that lead to SD and will contribute to the development of novel disease control tools.
Collapse
Affiliation(s)
- Matheus O Costa
- Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK. Canada; Department of Population Health, Faculty of Veterinary Medicine, Utrecht University. Utrecht, the Netherlands.
| | - John C S Harding
- Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK. Canada
| |
Collapse
|
103
|
Ferrari E, Palma C, Vesentini S, Occhetta P, Rasponi M. Integrating Biosensors in Organs-on-Chip Devices: A Perspective on Current Strategies to Monitor Microphysiological Systems. BIOSENSORS 2020; 10:E110. [PMID: 32872228 PMCID: PMC7558092 DOI: 10.3390/bios10090110] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 01/20/2023]
Abstract
Organs-on-chip (OoC), often referred to as microphysiological systems (MPS), are advanced in vitro tools able to replicate essential functions of human organs. Owing to their unprecedented ability to recapitulate key features of the native cellular environments, they represent promising tools for tissue engineering and drug screening applications. The achievement of proper functionalities within OoC is crucial; to this purpose, several parameters (e.g., chemical, physical) need to be assessed. Currently, most approaches rely on off-chip analysis and imaging techniques. However, the urgent demand for continuous, noninvasive, and real-time monitoring of tissue constructs requires the direct integration of biosensors. In this review, we focus on recent strategies to miniaturize and embed biosensing systems into organs-on-chip platforms. Biosensors for monitoring biological models with metabolic activities, models with tissue barrier functions, as well as models with electromechanical properties will be described and critically evaluated. In addition, multisensor integration within multiorgan platforms will be further reviewed and discussed.
Collapse
Affiliation(s)
| | | | | | | | - Marco Rasponi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, 20133 Milano, Italy; (E.F.); (C.P.); (S.V.); (P.O.)
| |
Collapse
|
104
|
Racova Z, Anzenbacherova E, Papouskova B, Poschner S, Kucova P, Gausterer JC, Gabor F, Kolar M, Anzenbacher P. Metabolite profiling of natural substances in human: in vitro study from fecal bacteria to colon carcinoma cells (Caco-2). J Nutr Biochem 2020; 85:108482. [PMID: 32801030 DOI: 10.1016/j.jnutbio.2020.108482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 07/02/2020] [Accepted: 08/03/2020] [Indexed: 01/13/2023]
Abstract
Flavonoids, including anthocyanins, are polyphenolic compounds present in fruits, vegetables and dietary supplements. They can be absorbed from the intestine to the bloodstream or pass into the large intestine. Various bacterial species and enzymes are present along the entire intestine. The aim of the present work was to investigate the intestinal metabolism of selected dietary polyphenol and polyphenol glycosides (quercetin, cyanidin-3-O-glucoside, cyanidin-3-O-galactoside, and delphinidin-3-O-galactoside) by human fecal bacteria. Moreover, the metabolism of metabolites formed from these compounds in human colon carcinoma cells (Caco-2) was also point of the interest. Test compounds were added to fresh human stool in broth or to Caco-2 cells in medium and then incubated for 6 or 20 h at 37°C. After incubation, samples were prepared for LC/MS determination. Main metabolic pathways were deglycosylation, hydrogenation, methylation, hydroxylation, and decomposition. 2,4,5-trihydroxybenzaldehyde, as a metabolite of cyanidin glycosides, was detected after incubation for the first time. Metabolites formed by fecal bacteria were further glucuronidated or methylated by intestinal enzymes. This metabolite profiling of natural compounds has helped to better understand the complex metabolism in the human intestine and this work also has shown the connection of metabolism of natural substances by intestinal bacteria followed by metabolism in intestinal cells.
Collapse
Affiliation(s)
- Zuzana Racova
- Department of Pharmacology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Czech Republic.
| | - Eva Anzenbacherova
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacky University Olomouc, Czech Republic
| | - Barbora Papouskova
- Department of Analytical Chemistry, Faculty of Science, Palacky University Olomouc, Czech Republic
| | - Stefan Poschner
- Division of Clinical Pharmacy and Diagnostics, Department of Pharmaceutical Chemistry, University of Vienna, Austria
| | - Pavla Kucova
- Department of Microbiology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Czech Republic
| | - Julia Clara Gausterer
- Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Austria
| | - Franz Gabor
- Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Austria
| | - Milan Kolar
- Department of Microbiology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Czech Republic
| | - Pavel Anzenbacher
- Department of Pharmacology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Czech Republic
| |
Collapse
|
105
|
Veisseire P, Bonnet M, Saraoui T, Poupet C, Camarès O, Gachinat M, Callon C, Febvre G, Chassard C, Bornes S. Investigation into In Vitro and In Vivo Caenorhabditis elegans Models to Select Cheese Yeasts as Probiotic Candidates for their Preventive Effects against Salmonella Typhimurium. Microorganisms 2020; 8:microorganisms8060922. [PMID: 32570901 PMCID: PMC7356738 DOI: 10.3390/microorganisms8060922] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/12/2020] [Accepted: 06/17/2020] [Indexed: 12/17/2022] Open
Abstract
The design of multiscale strategies integrating in vitro and in vivo models is necessary for the selection of new probiotics. In this regard, we developed a screening assay based on the investigation of the potential of yeasts from cheese as probiotics against the pathogen Salmonella Typhimurium UPsm1 (ST). Two yeasts isolated from raw-milk cheese (Saccharomyces cerevisiae 16, Sc16; Debaryomyces hansenii 25, Dh25), as well as S. cerevisiae subspecies boulardii (CNCM I-1079, Sb1079), were tested against ST by applying in vitro and in vivo tests. Adherence measurements to Caco-2 and HT29-MTX intestinal cells indicated that the two tested cheese yeasts presented a better adhesion than the probiotic Sb1079 as the control strain. Further, the Dh25 was the cheese yeast most likely to survive in the gastrointestinal tract. What is more, the modulation of the TransEpithelial Electrical Resistance (TEER) of differentiated Caco-2 cell monolayers showed the ability of Dh25 to delay the deleterious effects of ST. The influence of microorganisms on the in vivo model Caenorhabditis elegans was evaluated by measuring the longevity of the worm. This in vivo approach revealed that this yeast increased the worm’s lifespan and protected it against ST infection, confirming that this in vivo model can be useful for screening probiotic cheese yeasts.
Collapse
Affiliation(s)
- Philippe Veisseire
- Université Clermont Auvergne, INRAE, VetAgro Sup, F-15000 Aurillac, France; (M.B.); (T.S.); (C.P.); (O.C.); (M.G.); (C.C.); (C.C.); (S.B.)
- Correspondence: ; Tel.: +33-(0)4-43-79-11-28
| | - Muriel Bonnet
- Université Clermont Auvergne, INRAE, VetAgro Sup, F-15000 Aurillac, France; (M.B.); (T.S.); (C.P.); (O.C.); (M.G.); (C.C.); (C.C.); (S.B.)
| | - Taous Saraoui
- Université Clermont Auvergne, INRAE, VetAgro Sup, F-15000 Aurillac, France; (M.B.); (T.S.); (C.P.); (O.C.); (M.G.); (C.C.); (C.C.); (S.B.)
| | - Cyril Poupet
- Université Clermont Auvergne, INRAE, VetAgro Sup, F-15000 Aurillac, France; (M.B.); (T.S.); (C.P.); (O.C.); (M.G.); (C.C.); (C.C.); (S.B.)
| | - Olivier Camarès
- Université Clermont Auvergne, INRAE, VetAgro Sup, F-15000 Aurillac, France; (M.B.); (T.S.); (C.P.); (O.C.); (M.G.); (C.C.); (C.C.); (S.B.)
| | - Marylise Gachinat
- Université Clermont Auvergne, INRAE, VetAgro Sup, F-15000 Aurillac, France; (M.B.); (T.S.); (C.P.); (O.C.); (M.G.); (C.C.); (C.C.); (S.B.)
| | - Cécile Callon
- Université Clermont Auvergne, INRAE, VetAgro Sup, F-15000 Aurillac, France; (M.B.); (T.S.); (C.P.); (O.C.); (M.G.); (C.C.); (C.C.); (S.B.)
| | - Guy Febvre
- Université Clermont Auvergne, Laboratoire Météorologie Physique, CNRS, F-15000 Aurillac, France;
| | - Christophe Chassard
- Université Clermont Auvergne, INRAE, VetAgro Sup, F-15000 Aurillac, France; (M.B.); (T.S.); (C.P.); (O.C.); (M.G.); (C.C.); (C.C.); (S.B.)
| | - Stéphanie Bornes
- Université Clermont Auvergne, INRAE, VetAgro Sup, F-15000 Aurillac, France; (M.B.); (T.S.); (C.P.); (O.C.); (M.G.); (C.C.); (C.C.); (S.B.)
| |
Collapse
|
106
|
The gaseous gastrointestinal tract of a seawater teleost, the English sole (Parophrys vetulus). Comp Biochem Physiol A Mol Integr Physiol 2020; 247:110743. [PMID: 32531535 DOI: 10.1016/j.cbpa.2020.110743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/04/2020] [Accepted: 06/05/2020] [Indexed: 02/07/2023]
Abstract
There has been considerable recent progress in understanding the respiratory physiology of the gastrointestinal tract (GIT) in teleosts, but the respiratory conditions inside the GIT remain largely unknown, particularly the luminal PCO2 and PO2 levels. The GIT of seawater teleosts is of special interest due to its additional function of water absorption linked to HCO3- secretion, a process that may raise luminal PCO2 levels. Direct measurements of GIT PCO2 and PO2 using micro-optodes in the English sole (Parophrys vetulus; anaesthetized, artificially ventilated, 10-12 °C) revealed extreme luminal gas levels. Luminal PCO2 was 14-17 mmHg in the stomach and intestinal segments of fasted sole, considerably higher than arterial blood levels of 5 mmHg. Moreover, feeding, which raised intestinal HCO3- concentration, also raised luminal PCO2 to 34-50 mmHg. All these values were higher than comparable measurements in freshwater teleosts, and also greater than environmental CO2 levels of concern in aquaculture or global change scenarios. The PCO2 values in subintestinal vein blood draining the GIT of fed fish (28 mmHg) suggested some degree of equilibration with high luminal PCO2, whereas subintestinal vein PO2 levels were relatively low (9 mmHg). All luminal sections of the GIT were virtually anoxic (PO2 ≤ 0.3 mmHg), in both fasted and fed animals, a novel finding in teleosts.
Collapse
|
107
|
Stolaki M, Minekus M, Venema K, Lahti L, Smid EJ, Kleerebezem M, Zoetendal EG. Microbial communities in a dynamic in vitro model for the human ileum resemble the human ileal microbiota. FEMS Microbiol Ecol 2020; 95:5531306. [PMID: 31295351 DOI: 10.1093/femsec/fiz096] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 07/10/2019] [Indexed: 01/25/2023] Open
Abstract
The important role for the human small intestinal microbiota in health and disease has been widely acknowledged. However, the difficulties encountered in accessing the small intestine in a non-invasive way in healthy subjects have limited the possibilities to study its microbiota. In this study, a dynamic in vitro model that simulates the human ileum was developed, including its microbiota. Ileostomy effluent and fecal inocula were employed to cultivate microbial communities within the in vitro model. Microbial stability was repetitively achieved after 10 days of model operation with bacterial concentrations reaching on average 107 to 108 16S rRNA copy numbers/ml. High diversities similar to those observed in in vivo ileum samples were achieved at steady state using both fecal and ileostomy effluent inocula. Functional stability based on Short Chain Fatty Acid concentrations was reached after 10 days of operation using fecal inocula, but was not reached with ileostomy effluent as inoculum. Principal Components and cluster analysis of the phylogenetic profiles revealed that in vitro samples at steady state clustered closest to two samples obtained from the terminal ileum of healthy individuals, independent of the inoculum used, demonstrating that the in vitro microbiota at steady state resembles that of the human ileum.
Collapse
Affiliation(s)
- Maria Stolaki
- Top Institute Food and Nutrition, P.O. Box 557, 6700 AN Wageningen, the Netherlands.,Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, the Netherlands.,The Netherlands Organization for Applied Scientific Research (TNO), PO Box 360, 3700 AJ Zeist, The Netherlands
| | - Mans Minekus
- The Netherlands Organization for Applied Scientific Research (TNO), PO Box 360, 3700 AJ Zeist, The Netherlands
| | - Koen Venema
- Top Institute Food and Nutrition, P.O. Box 557, 6700 AN Wageningen, the Netherlands.,Maastricht University - Campus Venlo, Centre for Healthy Eating & Food Innovation, St. Jansweg 20, 5928 RC Venlo, The Netherlands
| | - Leo Lahti
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, the Netherlands.,Department of Mathematics and Statistics, FI-20014 University of Turku, Finland
| | - Eddy J Smid
- Top Institute Food and Nutrition, P.O. Box 557, 6700 AN Wageningen, the Netherlands.,Laboratory of Food Microbiology, Wageningen University & Research, P.O.Box 17, 6700 AA Wageningen, the Netherlands
| | - Michiel Kleerebezem
- Top Institute Food and Nutrition, P.O. Box 557, 6700 AN Wageningen, the Netherlands.,Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, the Netherlands.,Host-microbe Interactomics Group, Wageningen University & Research, De Elst 1, 6708 WD, Wageningen, the Netherlands
| | - Erwin G Zoetendal
- Top Institute Food and Nutrition, P.O. Box 557, 6700 AN Wageningen, the Netherlands.,Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, the Netherlands
| |
Collapse
|
108
|
Spatz M, Richard ML. Overview of the Potential Role of Malassezia in Gut Health and Disease. Front Cell Infect Microbiol 2020; 10:201. [PMID: 32528901 PMCID: PMC7265801 DOI: 10.3389/fcimb.2020.00201] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 04/16/2020] [Indexed: 12/19/2022] Open
Abstract
Malassezia is the most prevalent fungus identified in the human skin microbiota; originally described at the end of the nineteenth century, this genus is composed of at least 14 species. The role of Malassezia on the skin remains controversial because this genus has been associated with both healthy skin and pathologies (dermatitis, eczema, etc.). However, with the recent development of next-generation sequencing methods, allowing the description of the fungal diversity of various microbiota, Malassezia has also been identified as a resident fungus of diverse niches such as the gut or breast milk. A potential role for Malassezia in gut inflammation and cancer has also been suggested by recent studies. The aim of this review is to describe the findings on Malassezia in these unusual niches, to investigate what is known of the adaptation of Malassezia to the gut environment and to speculate on the role of this yeast in the host physiology specifically related to the gastrointestinal tract.
Collapse
Affiliation(s)
- Madeleine Spatz
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Mathias L Richard
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| |
Collapse
|
109
|
Zamora CY, Ward EM, Kester JC, Chen WLK, Velazquez JG, Griffith LG, Imperiali B. Application of a gut-immune co-culture system for the study of N-glycan-dependent host-pathogen interactions of Campylobacter jejuni. Glycobiology 2020; 30:374-381. [PMID: 31965157 PMCID: PMC7234929 DOI: 10.1093/glycob/cwz105] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 12/09/2019] [Accepted: 12/10/2019] [Indexed: 12/26/2022] Open
Abstract
An in vitro gut-immune co-culture model with apical and basal accessibility, designed to more closely resemble a human intestinal microenvironment, was employed to study the role of the N-linked protein glycosylation pathway in Campylobacter jejuni pathogenicity. The gut-immune co-culture (GIC) was developed to model important aspects of the human small intestine by the inclusion of mucin-producing goblet cells, human enterocytes and dendritic cells, bringing together a mucus-containing epithelial monolayer with elements of the innate immune system. The utility of the system was demonstrated by characterizing host-pathogen interactions facilitated by N-linked glycosylation, such as host epithelial barrier functions, bacterial invasion and immunogenicity. Changes in human intestinal barrier functions in the presence of 11168 C. jejuni (wildtype) strains were quantified using GICs. The glycosylation-impaired strain 11168 ΔpglE was 100-fold less capable of adhering to and invading this intestinal model in cell infectivity assays. Quantification of inflammatory signaling revealed that 11168ΔpglE differentially modulated inflammatory responses in different intestinal microenvironments, suppressive in some but activating in others. Virulence-associated outer membrane vesicles produced by wildtype and 11168ΔpglE C. jejuni were shown to have differential composition and function, with both leading to immune system activation when provided to the gut-immune co-culture model. This analysis of aspects of C. jejuni infectivity in the presence and absence of its N-linked glycome is enabled by application of the gut-immune model, and we anticipate that this system will be applicable to further studies of C. jejuni and other enteropathogens of interest.
Collapse
Affiliation(s)
- Cristina Y Zamora
- Department of Biology, Massachusetts Institute of Technology, 31 Ames St, Cambridge, MA 02142, USA
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA
| | - Elizabeth M Ward
- Department of Biology, Massachusetts Institute of Technology, 31 Ames St, Cambridge, MA 02142, USA
- Microbiology Graduate Program, Massachusetts Institute of Technology, 31 Ames St, Cambridge, MA 02142, USA
| | - Jemila C Kester
- Department of Biological Engineering, Massachusetts Institute of Technology, 21 Ames St, Cambridge, MA 02142, USA
| | - Wen Li Kelly Chen
- Department of Biological Engineering, Massachusetts Institute of Technology, 21 Ames St, Cambridge, MA 02142, USA
| | - Jason G Velazquez
- Department of Biological Engineering, Massachusetts Institute of Technology, 21 Ames St, Cambridge, MA 02142, USA
| | - Linda G Griffith
- Department of Biological Engineering, Massachusetts Institute of Technology, 21 Ames St, Cambridge, MA 02142, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 33 Massachusetts Ave, Cambridge, 02139, USA
| | - Barbara Imperiali
- Department of Biology, Massachusetts Institute of Technology, 31 Ames St, Cambridge, MA 02142, USA
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA
| |
Collapse
|
110
|
Khademian M, Imlay JA. Do reactive oxygen species or does oxygen itself confer obligate anaerobiosis? The case of Bacteroides thetaiotaomicron. Mol Microbiol 2020; 114:333-347. [PMID: 32301184 DOI: 10.1111/mmi.14516] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/07/2020] [Accepted: 04/07/2020] [Indexed: 02/06/2023]
Abstract
Bacteroides thetaiotaomicron was examined to determine whether its obligate anaerobiosis is imposed by endogenous reactive oxygen species or by molecular oxygen itself. Previous analyses established that aerated B. thetaiotaomicron loses some enzyme activities due to a high rate of endogenous superoxide formation. However, the present study establishes that another key step in central metabolism is poisoned by molecular oxygen itself. Pyruvate dissimilation was shown to depend upon two enzymes, pyruvate:formate lyase (PFL) and pyruvate:ferredoxin oxidoreductase (PFOR), that lose activity upon aeration. PFL is a glycyl-radical enzyme whose vulnerability to oxygen is already understood. The rate of PFOR damage was unaffected by the level of superoxide or peroxide, showing that molecular oxygen itself is the culprit. The cell cannot repair PFOR, which amplifies the impact of damage. The rates of PFOR and fumarase inactivation are similar, suggesting that superoxide dismutase is calibrated so the oxygen- and superoxide-sensitive enzymes are equally sensitive to aeration. The physiological purpose of PFL and PFOR is to degrade pyruvate without disrupting the redox balance, and they do so using catalytic mechanisms that are intrinsically vulnerable to oxygen. In this way, the anaerobic excellence and oxygen sensitivity of B. thetaiotaomicron are two sides of the same coin.
Collapse
Affiliation(s)
- Maryam Khademian
- Department of Microbiology, University of Illinois, Urbana, IL, USA
| | - James A Imlay
- Department of Microbiology, University of Illinois, Urbana, IL, USA
| |
Collapse
|
111
|
Guo Y, Lee H, Jeong H. Gut microbiota in reductive drug metabolism. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 171:61-93. [PMID: 32475528 DOI: 10.1016/bs.pmbts.2020.04.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Gut bacteria are predominant microorganisms in the gut microbiota and have been recognized to mediate a variety of biotransformations of xenobiotic compounds in the gut. This review is focused on one of the gut bacterial xenobiotic metabolisms, reduction. Xenobiotics undergo different types of reductive metabolisms depending on chemically distinct groups: azo (-NN-), nitro (-NO2), alkene (-CC-), ketone (-CO), N-oxide (-NO), and sulfoxide (-SO). In this review, we have provided select examples of drugs in six chemically distinct groups that are known or suspected to be subjected to the reduction by gut bacteria. For some drugs, responsible enzymes in specific gut bacteria have been identified and characterized, but for many drugs, only circumstantial evidence is available that indicates gut bacteria-mediated reductive metabolism. The physiological roles of even known gut bacterial enzymes have not been well defined.
Collapse
Affiliation(s)
- Yukuang Guo
- Department of Pharmaceutical Sciences, Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, United States
| | - Hyunwoo Lee
- Department of Pharmaceutical Sciences, Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, United States.
| | - Hyunyoung Jeong
- Department of Pharmaceutical Sciences, Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, United States.
| |
Collapse
|
112
|
Ambrosini YM, Shin W, Min S, Kim HJ. Microphysiological Engineering of Immune Responses in Intestinal Inflammation. Immune Netw 2020; 20:e13. [PMID: 32395365 PMCID: PMC7192834 DOI: 10.4110/in.2020.20.e13] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/18/2020] [Accepted: 03/10/2020] [Indexed: 02/07/2023] Open
Abstract
The epithelial barrier in the gastrointestinal (GI) tract is a protective interface that endures constant exposure to the external environment while maintaining its close contact with the local immune system. Growing evidence has suggested that the intercellular crosstalk in the GI tract contributes to maintaining the homeostasis in coordination with the intestinal microbiome as well as the tissue-specific local immune elements. Thus, it is critical to map the complex crosstalks in the intestinal epithelial-microbiome-immune (EMI) axis to identify a pathological trigger in the development of intestinal inflammation, including inflammatory bowel disease. However, deciphering a specific contributor to the onset of pathophysiological cascades has been considerably hindered by the challenges in current in vivo and in vitro models. Here, we introduce various microphysiological engineering models of human immune responses in the EMI axis under the healthy conditions and gut inflammation. As a prospective model, we highlight how the human “gut inflammation-on-a-chip” can reconstitute the pathophysiological immune responses and contribute to understanding the independent role of inflammatory factors in the EMI axis on the initiation of immune responses under barrier dysfunction. We envision that the microengineered immune models can be useful to build a customizable patient's chip for the advance in precision medicine.
Collapse
Affiliation(s)
- Yoko M Ambrosini
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.,Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011 USA
| | - Woojung Shin
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Soyoun Min
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Hyun Jung Kim
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA.,Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA
| |
Collapse
|
113
|
Raise A, Dupont S, Iaconelli C, Caliri C, Charriau A, Gervais P, Chambin O, Beney L. Comparison of two encapsulation processes to protect the commensal gut probiotic bacterium Faecalibacterium prausnitzii from the digestive tract. J Drug Deliv Sci Technol 2020. [DOI: 10.1016/j.jddst.2020.101608] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
114
|
McDermott TR, Stolz JF, Oremland RS. Arsenic and the gastrointestinal tract microbiome. ENVIRONMENTAL MICROBIOLOGY REPORTS 2020; 12:136-159. [PMID: 31773890 DOI: 10.1111/1758-2229.12814] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/23/2019] [Accepted: 11/25/2019] [Indexed: 06/10/2023]
Abstract
Arsenic is a toxin, ranking first on the Agency for Toxic Substances and Disease Registry and the Environmental Protection Agency Priority List of Hazardous Substances. Chronic exposure increases the risk of a broad range of human illnesses, most notably cancer; however, there is significant variability in arsenic-induced disease among exposed individuals. Human genetics is a known component, but it alone cannot account for the large inter-individual variability in the presentation of arsenicosis symptoms. Each part of the gastrointestinal tract (GIT) may be considered as a unique environment with characteristic pH, oxygen concentration, and microbiome. Given the well-established arsenic redox transformation activities of microorganisms, it is reasonable to imagine how the GIT microbiome composition variability among individuals could play a significant role in determining the fate, mobility and toxicity of arsenic, whether inhaled or ingested. This is a relatively new field of research that would benefit from early dialogue aimed at summarizing what is known and identifying reasonable research targets and concepts. Herein, we strive to initiate this dialogue by reviewing known aspects of microbe-arsenic interactions and placing it in the context of potential for influencing host exposure and health risks. We finish by considering future experimental approaches that might be of value.
Collapse
Affiliation(s)
- Timothy R McDermott
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, 59717, USA
| | - John F Stolz
- Department of Biological Sciences and Center for Environmental Research and Education, Duquesne University, Pittsburgh, PA, USA
| | | |
Collapse
|
115
|
Jiménez-González A, Xu F, Andersson JO. Lateral Acquisitions Repeatedly Remodel the Oxygen Detoxification Pathway in Diplomonads and Relatives. Genome Biol Evol 2020; 11:2542-2556. [PMID: 31504492 PMCID: PMC6934886 DOI: 10.1093/gbe/evz188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2019] [Indexed: 12/13/2022] Open
Abstract
Oxygen and reactive oxygen species (ROS) are important stress factors for cells because they can oxidize many large molecules. Fornicata, a group of flagellated protists that includes diplomonads, have anaerobic metabolism but are still able to tolerate fluctuating levels of oxygen. We identified 25 protein families putatively involved in detoxification of oxygen and ROS in this group using a bioinformatics approach and propose how these interact in an oxygen detoxification pathway. These protein families were divided into a central oxygen detoxification pathway and accessory pathways for the synthesis of nonprotein thiols. We then used a phylogenetic approach to investigate the evolutionary origin of the components of this putative pathway in Diplomonadida and other Fornicata species. Our analyses suggested that the diplomonad ancestor was adapted to low-oxygen levels, was able to reduce O2 to H2O in a manner similar to extant diplomonads, and was able to synthesize glutathione and l-cysteine. Several genes involved in the pathway have complex evolutionary histories and have apparently been repeatedly acquired through lateral gene transfer and subsequently lost. At least seven genes were acquired independently in different Fornicata lineages, leading to evolutionary convergences. It is likely that acquiring these oxygen detoxification proteins helped anaerobic organisms (like the parasitic Giardia intestinalis) adapt to low-oxygen environments (such as the digestive tract of aerobic hosts).
Collapse
Affiliation(s)
- Alejandro Jiménez-González
- Uppsala Biomedicine Centre, Department of Cell and Molecular Biology, Molecular Evolution Program, Uppsala University, Sweden
| | - Feifei Xu
- Uppsala Biomedicine Centre, Department of Cell and Molecular Biology, Microbiology Program, Uppsala University, Sweden
| | - Jan O Andersson
- Uppsala Biomedicine Centre, Department of Cell and Molecular Biology, Molecular Evolution Program, Uppsala University, Sweden
| |
Collapse
|
116
|
Ilhan ZE, DiBaise JK, Dautel SE, Isern NG, Kim YM, Hoyt DW, Schepmoes AA, Brewer HM, Weitz KK, Metz TO, Crowell MD, Kang DW, Rittmann BE, Krajmalnik-Brown R. Temporospatial shifts in the human gut microbiome and metabolome after gastric bypass surgery. NPJ Biofilms Microbiomes 2020; 6:12. [PMID: 32170068 PMCID: PMC7070067 DOI: 10.1038/s41522-020-0122-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 02/14/2020] [Indexed: 02/08/2023] Open
Abstract
Although the etiology of obesity is not well-understood, genetic, environmental, and microbiome elements are recognized as contributors to this rising pandemic. It is well documented that Roux-en-Y gastric bypass (RYGB) surgery drastically alters the fecal microbiome, but data are sparse on temporal and spatial microbiome and metabolome changes, especially in human populations. We characterized the structure and function (through metabolites) of the microbial communities in the gut lumen and structure of microbial communities on mucosal surfaces in nine morbidly obese individuals before, 6 months, and 12 months after RYGB surgery. Moreover, using a comprehensive multi-omic approach, we compared this longitudinal cohort to a previously studied cross-sectional cohort (n = 24). In addition to the expected weight reduction and improvement in obesity-related comorbidities after RYGB surgery, we observed that the impact of surgery was much greater on fecal communities in comparison to mucosal ones. The changes in the fecal microbiome were linked to increased concentrations of branched-chain fatty acids and an overall decrease in secondary bile acid concentrations. The microbiome and metabolome data sets for this longitudinal cohort strengthen our understanding of the persistent impact of RYGB on the gut microbiome and its metabolism. Our findings highlight the importance of changes in mucosal and fecal microbiomes after RYGB surgery. The spatial modifications in the microbiome after RYGB surgery corresponded to persistent changes in fecal fermentation and bile acid metabolism, both of which are associated with improved metabolic outcomes.
Collapse
Affiliation(s)
- Zehra Esra Ilhan
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, USA.
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, USA.
| | - John K DiBaise
- Mayo Clinic, Division of Gastroenterology, Scottsdale, AZ, USA
| | - Sydney E Dautel
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Nancy G Isern
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Young-Mo Kim
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - David W Hoyt
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Athena A Schepmoes
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Heather M Brewer
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Karl K Weitz
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Thomas O Metz
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | | | - Dae-Wook Kang
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, USA
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, USA
- Department of Civil & Environmental Engineering, The University of Toledo, Toledo, OH, USA
| | - Bruce E Rittmann
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, USA
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA
| | - Rosa Krajmalnik-Brown
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, USA.
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, USA.
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA.
| |
Collapse
|
117
|
Rocha BS, Laranjinha J. Nitrate from diet might fuel gut microbiota metabolism: Minding the gap between redox signaling and inter-kingdom communication. Free Radic Biol Med 2020; 149:37-43. [PMID: 32045656 DOI: 10.1016/j.freeradbiomed.2020.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/29/2020] [Accepted: 02/03/2020] [Indexed: 12/19/2022]
Abstract
The gut microbiota has been recently interpreted in terms of a metabolic organ that influences the host through reciprocal interactions, encompassing metabolic and immune pathways, genetic and epigenetic programming in host mammal tissues in a diet-depended manner, that shape virtually all aspects of host physiology. In this scenario, dietary nitrate, a major component of leafy green vegetables known for their health benefits, might fuel microbiota metabolism with ensued consequences for microbiota-host interaction. Cumulating evidence support that nitrate shapes oral microbiome communities with impact on the kinetics and systemic levels of both nitrate and nitrite. However, the impact of nitrate, which is steadily delivered into the lower gastrointestinal tract after a vegetable-rich meal, in the intestinal microbiome communities and their functional capacity remains largely elusive. Several mechanisms reinforce the notion that nitrate may be a nutrient for the lower microbiome and might participate in local redox interactions with relevance for bacteria-host interactions, among these nitric oxide-dependent mechanisms along the nitrate-nitrite-nitric oxide pathway. Also, by allowing bacteria to thrive, either by increasing microbial biomass or by acting as a respiratory substrate for the existing communities, nitrate ensures the production of bacterial metabolites (e.g., pathogen-associated molecular patterns, PAMP, short chain fatty acids, among other) that are recognised by host receptors (such as toll-like, TLR, and formyl peptide receptors, FPR) thereby activating local signalling pathways. Here, we elaborate on the notion that via modulation of intestinal microbiota metabolism, dietary nitrate impacts on host-microbiota metabolic and redox interactions, thereby contributing as an essential nutrient to optimal health.
Collapse
Affiliation(s)
- Bárbara S Rocha
- Faculty of Pharmacy and Center for Neuroscience and Cell Biology, University of Coimbra, Health Sciences Campus, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal.
| | - João Laranjinha
- Faculty of Pharmacy and Center for Neuroscience and Cell Biology, University of Coimbra, Health Sciences Campus, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal
| |
Collapse
|
118
|
Sbardellati DL, Fischer A, Cox MS, Li W, Kalscheur KF, Suen G. The bovine epimural microbiota displays compositional and structural heterogeneity across different ruminal locations. J Dairy Sci 2020; 103:3636-3647. [PMID: 32057427 DOI: 10.3168/jds.2019-17649] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/16/2019] [Indexed: 01/01/2023]
Abstract
Dairy cattle are globally important agricultural animals. Central to their biology is the rumen, which houses an essential microbial community, or microbiome, important for providing nutrition from otherwise host-inaccessible dietary components. The rumen environment is noted for its substantial spatial heterogeneity, as illustrated by the stratification into ruminal solid and liquid phases. A third microbiota found directly attached to the ruminal epithelium (the epimural microbiota) also exists but is less well understood because of challenges in sampling the ruminal epithelium. As a result, our understanding of the epimural microbiota is based on analyses of cannulated animals sampled at a single location-the ventral sac-and does not account for other ruminal locations, which may have importance for overall rumen function. To address this knowledge gap, we hypothesize that the epimural microbiota at different ruminal locations differs due to known morphological, physiological, and functional differences across the geographic spread of the rumen epithelium. Here, we characterized bacterial epimural communities at different sites within 8 lactating Holstein dairy cows using 16S rRNA gene sequencing. Four different sites were sampled via rumen tissue biopsy: cranial sac (CS), ventral sac (VS), caudodorsal blind sac (CDBS), and caudoventral blind sac (CVBS). We found that locations differed in both epimural bacterial community structure and composition, with the CDBS community displaying the greatest diversity. Across all sampling sites, epimural bacterial communities were dominated by members of the phyla Bacteroidetes, Firmicutes, and Proteobacteria. Bacteria within Prevotellaceae, Butyrivibrio, Campylobacter, Mogibacterium, and Desulfobulbus all showed high relative sequence abundance and differential distributions according to sample location. There appears to be a core epimural microbiota present across all locations in all cows, although relative abundance was highly variable. The difference in relative abundance in epimural microbial communities, perhaps influenced by host physiology and the diversity within rumen contents, likely has important consequences for nutrition acquisition and general health. To the best of our knowledge, this work represents the first characterization of the ruminal epimural microbiota across different epithelial locations for any bovine ruminant.
Collapse
Affiliation(s)
- D L Sbardellati
- Department of Bacteriology, University of Wisconsin-Madison, Madison 53706
| | - A Fischer
- US Dairy Forage Research Center, USDA-Agricultural Research Service, Madison, WI 53706
| | - M S Cox
- Department of Bacteriology, University of Wisconsin-Madison, Madison 53706
| | - W Li
- US Dairy Forage Research Center, USDA-Agricultural Research Service, Madison, WI 53706
| | - K F Kalscheur
- US Dairy Forage Research Center, USDA-Agricultural Research Service, Madison, WI 53706
| | - G Suen
- Department of Bacteriology, University of Wisconsin-Madison, Madison 53706.
| |
Collapse
|
119
|
Eran Nagar E, Okun Z, Shpigelman A. Digestive fate of polyphenols: updated view of the influence of chemical structure and the presence of cell wall material. Curr Opin Food Sci 2020. [DOI: 10.1016/j.cofs.2019.10.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
120
|
Hypothermia during Surgical Treatment of Type A Aortic Dissection: A 16 Years' Experience. Int J Vasc Med 2020; 2020:3893261. [PMID: 34367694 PMCID: PMC8339990 DOI: 10.1155/2020/3893261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 09/02/2019] [Accepted: 10/15/2019] [Indexed: 11/25/2022] Open
Abstract
Acute aortic dissection (AAD) is among the most challenging cases for surgical treatment and requires procedural expertise for its safe conduct. Aortic surgery has undergone several changes over the last years, especially concerning cerebral protection. The brilliant results obtained with the aid of selective anterograde cerebral perfusion led to a progressive increase of circulatory arrest temperature, with the rise of safe time along with a reduction of the extracorporeal circulation time and hypothermia-related side effects. However, there is still no definitive consensus concerning the optimal range of temperature to be used during circulatory arrest. Objectives. This is a retrospective observational study, and we examined 16-year trends in the presentation, diagnosis, hospital outcome and treatment of A AAD type. In our Cardiac Surgery Unit in Policlinico Umberto I of Rome, our analysis focused on patients, who received ACP during aortic surgery and we analyzed the differences between two distinct groups based on the lowest temperature reached during CPB conduction: Lower Temperature Group (LT) (T < 24°C) versus Higher Temperature Group (HT) (T ≥ 24°C) arrest circulation temperature. Methods. Data from 241 patients enrolled between August 2002 and March 2018 were analyzed. Patients were divided according to the lowest temperature reached into 2 groups: Lower Temperature group (LT) (94 patients) and Higher Temperature Group (HT) (147 patients). Results. Our results showed a significant reduction of in-hospital mortality and in-hospital results in patients with higher CPB temperature. The global incidence of complications was statistically reduced in HT group: we found a statistical significant reduction of intestinal ischemia, and a similar trend also for other complications analyzed, such as infections. Since the two groups were similar for type of surgical procedures, we considered these differences depending on the lower temperature value reached, according to the current literature. Conclusions. We found a significantly higher mortality in patients with lower temperature during CPB and a global reduction of complications and in particular a significant reduction of intestinal ischemia in patients with higher temperature during CPB. We found a similar trend in other fields of investigations, so we can conclude that circulatory arrest performed at temperature ≥24°C nasopharyngeal temperature associated with ACP is a safe strategy for aortic surgery for AAD.
Collapse
|
121
|
Xiang Q, Wu X, Pan Y, Wang L, Cui C, Guo Y, Zhu L, Peng J, Wei H. Early-Life Intervention Using Fecal Microbiota Combined with Probiotics Promotes Gut Microbiota Maturation, Regulates Immune System Development, and Alleviates Weaning Stress in Piglets. Int J Mol Sci 2020; 21:ijms21020503. [PMID: 31941102 PMCID: PMC7014131 DOI: 10.3390/ijms21020503] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/01/2020] [Accepted: 01/07/2020] [Indexed: 02/07/2023] Open
Abstract
Previous studies have suggested that immune system development and weaning stress are closely related to the maturation of gut microbiota. The early-life period is a “window of opportunity” for microbial colonization, which potentially has a critical impact on the development of the immune system. Fecal microbiota transplantation (FMT) and probiotics are often used to regulate gut microbial colonization. This study aims to test whether early intervention with FMT using fecal microbiota from gestation sows combined with Clostridium butyricum and Saccharomyces boulardii (FMT-CS) administration could promote the maturation of gut microbiota and development of immune system in piglets. Piglets were assigned to control (n = 84) and FMT-CS treatment (n = 106), which were treated with placebo and bacterial suspension during the first three days after birth, respectively. By 16S rRNA gene sequencing, we found that FMT-CS increased the α-diversity and reduced the unweighted UniFrac distances of the OTU community. Besides, FMT-CS increased the relative abundance of beneficial bacteria, while decreasing that of opportunistic pathogens. FMT-CS also enhanced the relative abundance of genes related to cofactors and vitamin, energy, and amino acid metabolisms during the early-life period. ELISA analysis revealed that FMT-CS gave rise to the plasma concentrations of IL-23, IL-17, and IL-22, as well as the plasma levels of anti-M.hyo and anti-PCV2 antibodies. Furthermore, the FMT-CS-treated piglets showed decreases in inflammation levels and oxidative stress injury, and improvement of intestinal barrier function after weaning as well. Taken together, our results suggest that early-life intervention with FMT-CS could promote the development of innate and adaptive immune system and vaccine efficacy, and subsequently alleviate weaning stress through promoting the maturation of gut microbiota in piglets.
Collapse
Affiliation(s)
- Quanhang Xiang
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.X.); (X.W.); (Y.P.); (L.W.); (C.C.); (Y.G.); (L.Z.)
| | - Xiaoyu Wu
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.X.); (X.W.); (Y.P.); (L.W.); (C.C.); (Y.G.); (L.Z.)
| | - Ye Pan
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.X.); (X.W.); (Y.P.); (L.W.); (C.C.); (Y.G.); (L.Z.)
| | - Liu Wang
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.X.); (X.W.); (Y.P.); (L.W.); (C.C.); (Y.G.); (L.Z.)
| | - Chenbin Cui
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.X.); (X.W.); (Y.P.); (L.W.); (C.C.); (Y.G.); (L.Z.)
| | - Yuwei Guo
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.X.); (X.W.); (Y.P.); (L.W.); (C.C.); (Y.G.); (L.Z.)
| | - Lingling Zhu
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.X.); (X.W.); (Y.P.); (L.W.); (C.C.); (Y.G.); (L.Z.)
| | - Jian Peng
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.X.); (X.W.); (Y.P.); (L.W.); (C.C.); (Y.G.); (L.Z.)
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 400700, China
- Hubei Agricultural Sciences and Technology Innovation Center, Wuhan 430070, China
- Correspondence: (J.P.); (H.W.)
| | - Hongkui Wei
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.X.); (X.W.); (Y.P.); (L.W.); (C.C.); (Y.G.); (L.Z.)
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 400700, China
- Hubei Agricultural Sciences and Technology Innovation Center, Wuhan 430070, China
- Correspondence: (J.P.); (H.W.)
| |
Collapse
|
122
|
Sutton TDS, Hill C. Gut Bacteriophage: Current Understanding and Challenges. Front Endocrinol (Lausanne) 2019; 10:784. [PMID: 31849833 PMCID: PMC6895007 DOI: 10.3389/fendo.2019.00784] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 10/28/2019] [Indexed: 12/13/2022] Open
Abstract
The gut microbiome is widely accepted to have a significant impact on human health yet, despite years of research on this complex ecosystem, the contributions of different forces driving microbial population structure remain to be fully elucidated. The viral component of the human gut microbiome is dominated by bacteriophage, which are known to play crucial roles in shaping microbial composition, driving bacterial diversity, and facilitating horizontal gene transfer. Bacteriophage are also one of the most poorly understood components of the human gut microbiome, with the vast majority of viral sequences sharing little to no homology to reference databases. If we are to understand the dynamics of bacteriophage populations, their interaction with the human microbiome and ultimately their influence on human health, we will depend heavily on sequence based approaches and in silico tools. This is complicated by the fact that, as with any research field in its infancy, methods of analyses vary and this can impede our ability to compare the outputs of different studies. Here, we discuss the major findings to date regarding the human virome and reflect on our current understanding of how gut bacteriophage shape the microbiome. We consider whether or not the virome field is built on unstable foundations and if so, how can we provide a solid basis for future experimentation. The virome is a challenging yet crucial piece of the human microbiome puzzle. In order to develop our understanding, we will discuss the need to underpin future studies with robust research methods and suggest some solutions to existing challenges.
Collapse
Affiliation(s)
| | - Colin Hill
- APC Microbiome Ireland and School of Microbiology, University College Cork, Cork, Ireland
| |
Collapse
|
123
|
Antibiotic effects on gut microbiota, metabolism, and beyond. Appl Microbiol Biotechnol 2019; 103:9277-9285. [PMID: 31701196 DOI: 10.1007/s00253-019-10165-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/21/2019] [Accepted: 09/28/2019] [Indexed: 02/08/2023]
Abstract
Current advances on gut microbiota have broadened our view on host-microbiota interactions. As a microbiota-targeted approach, the use of antibiotics has been widely adopted to explore the role of gut microbiota in vivo. Antibiotics can change the microbial composition, resulting in varied effects, depending on the antibiotic class, dosage, and duration. Antibiotic intervention in early life leads to life-long phenotype alterations, including obesity. Antibiotic-induced changes in gut microbiota affect the epithelial utilization of both macronutrients (e.g., amino acids) and micronutrients (e.g., copper, vitamin E) and the redox homeostasis. Of particular interest is the regulation of gut anaerobiosis and aerobiosis by oxygen availability, which is closely related to epithelial metabolism. Additionally, antibiotic interventions enable to identify novel roles of gut microbiota in gut-liver axis and gut-brain axis. Indigenous antimicrobial molecules are produced by certain microbes, and they have the potential to affect function through eliciting changes in the gut microbiota. This review discusses at length these findings to gain a better and novel insight into microbiota-host interactions and the mechanisms involved.
Collapse
|
124
|
Kim R, Attayek PJ, Wang Y, Furtado KL, Tamayo R, Sims CE, Allbritton NL. An in vitro intestinal platform with a self-sustaining oxygen gradient to study the human gut/microbiome interface. Biofabrication 2019; 12:015006. [PMID: 31519008 DOI: 10.1088/1758-5090/ab446e] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
An oxygen gradient formed along the length of colonic crypts supports stem-cell proliferation at the normoxic crypt base while supporting obligate anaerobe growth in the anoxic colonic lumen. Primary human colonic epithelial cells derived from human gastrointestinal stem cells were cultured within a device possessing materials of tailored oxygen permeability to produce an oxygen-depleted luminal (0.8% ± 0.1% O2) and oxygen-rich basal (11.1% ± 0.5% O2) compartment. This oxygen difference created a stable oxygen gradient across the colonic epithelial cells which remained viable and properly polarized. Facultative and obligate anaerobes Lactobacillus rhamnosus, Bifidobacterium adolescentis, and Clostridium difficile grew readily within the luminal compartment. When formed along the length of an in vitro crypt, the oxygen gradient facilitated cell compartmentalization within the crypt by enhancing confinement of the proliferative cells to the crypt base. This platform provides a simple system to create a physiological oxygen gradient across an intestinal mimic while simultaneously supporting anaerobe co-culture.
Collapse
Affiliation(s)
- Raehyun Kim
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, and North Carolina State University, Raleigh, NC, United States of America
| | | | | | | | | | | | | |
Collapse
|
125
|
Zhao F, Zhou G, Liu X, Song S, Xu X, Hooiveld G, Müller M, Liu L, Kristiansen K, Li C. Dietary Protein Sources Differentially Affect the Growth of
Akkermansia muciniphila
and Maintenance of the Gut Mucus Barrier in Mice. Mol Nutr Food Res 2019; 63:e1900589. [DOI: 10.1002/mnfr.201900589] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/01/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Fan Zhao
- Key Laboratory of Meat Processing and Quality Control, MOE; Key Laboratory of Meat Processing, MARA; Jiangsu Collaborative Center of Meat Production, Processing and Quality Control; International Joint Laboratory of Animal Health and Food Safety, MOECollege of Food Science and TechnologyNanjing Agricultural University Nanjing 210095 P. R. China
| | - Guanghong Zhou
- Key Laboratory of Meat Processing and Quality Control, MOE; Key Laboratory of Meat Processing, MARA; Jiangsu Collaborative Center of Meat Production, Processing and Quality Control; International Joint Laboratory of Animal Health and Food Safety, MOECollege of Food Science and TechnologyNanjing Agricultural University Nanjing 210095 P. R. China
| | - Xinyue Liu
- Key Laboratory of Meat Processing and Quality Control, MOE; Key Laboratory of Meat Processing, MARA; Jiangsu Collaborative Center of Meat Production, Processing and Quality Control; International Joint Laboratory of Animal Health and Food Safety, MOECollege of Food Science and TechnologyNanjing Agricultural University Nanjing 210095 P. R. China
| | - Shangxin Song
- School of Food ScienceNanjing Xiaozhuang University Nanjing 211171 P. R. China
| | - Xinglian Xu
- Key Laboratory of Meat Processing and Quality Control, MOE; Key Laboratory of Meat Processing, MARA; Jiangsu Collaborative Center of Meat Production, Processing and Quality Control; International Joint Laboratory of Animal Health and Food Safety, MOECollege of Food Science and TechnologyNanjing Agricultural University Nanjing 210095 P. R. China
| | - Guido Hooiveld
- Nutrition, Metabolism and Genomics Group, Division of Human NutritionWageningen University Wageningen The Netherlands
| | - Michael Müller
- Norwich Medical SchoolUniversity of East Anglia Norwich UK
| | - Li Liu
- Glycomics and Glycan Bioengineering Research Center (GGBRC) Nanjing P. R. China
| | - Karsten Kristiansen
- Laboratory of Genomics and Molecular BiomedicineDepartment of BiologyUniversity of Copenhagen Copenhagen 2100 Denmark
- Institute of MetagenomicsBGI‐Shenzhen Shenzhen 518083 P. R. China
| | - Chunbao Li
- Key Laboratory of Meat Processing and Quality Control, MOE; Key Laboratory of Meat Processing, MARA; Jiangsu Collaborative Center of Meat Production, Processing and Quality Control; International Joint Laboratory of Animal Health and Food Safety, MOECollege of Food Science and TechnologyNanjing Agricultural University Nanjing 210095 P. R. China
| |
Collapse
|
126
|
Amino Acids and Ribose: Drivers of Protein and RNA Fermentation by Ingested Bacteria of a Primitive Gut Ecosystem. Appl Environ Microbiol 2019; 85:AEM.01297-19. [PMID: 31324631 PMCID: PMC6752017 DOI: 10.1128/aem.01297-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Accepted: 07/14/2019] [Indexed: 01/21/2023] Open
Abstract
Animal health is linked to gut ecosystems whose primary function is normally the digestion of dietary matter. Earthworms are representative of one of the oldest known animal lineages and, despite their primitive nature, have unique environmental impact by virtue of their dietary consumption of their habitat, i.e., soil-associated matter. A resident gut community is a hallmark of many gut ecosystems of evolutionarily more advanced animals, but the alimentary canal of earthworms is dominated by ingested transient soil microbes. Protein and RNA are (i) the primary organic components of microbial cells that are subject to lysis during gut passage and (ii) fermentable dietary substrates in the alimentary canal. This study examined the gut-associated fermentation of constituents of these biopolymers to determine how their fermentation is integrated to the microbiological dynamics of the gut and might contribute to earthworm-linked transformations of organic matter in the terrestrial biosphere. Earthworms are among the most primitive animals and are of fundamental importance to the turnover of organic matter in the terrestrial biosphere. These invertebrates ingest materials that are colonized by microbes, some of which are subject to disruption by the crop/gizzard or other lytic events during gut passage. Protein and RNA are dominant polymers of disrupted microbial cells, and these biopolymers facilitate robust fermentations by surviving ingested bacteria. To further resolve these fermentations, amino acids and ribose (as fermentable constituents of protein and RNA, respectively) were evaluated as potential drivers of fermentation in gut content of the model earthworm Lumbricus terrestris (taxa were examined with 16S rRNA-based analyses). Of eight amino acids tested, glutamate, aspartate, and threonine were most stimulatory and yielded dissimilar fermentations facilitated by contrasting taxa (e.g., glutamate stimulated the Fusobacteriaceae and yielded H2 and formate, whereas aspartate stimulated the Aeromonadaceae and yielded succinate and propionate). A marginal Stickland fermentation was associated with the Peptostreptococcaceae and Lachnospiraceae. Ribose fermentation yielded a complex product profile facilitated primarily by the Aeromonadaceae. The transient nature of succinate was linked to its decarboxylation to propionate and the Fusobacteriaceae, whereas the transient nature of formate was linked to formate-hydrogen lyase activity and the Peptostreptococcaceae. These findings reinforce the likelihood that (i) the animal host and hosted fermentative bacteria compete for the constituents of protein and RNA in the alimentary canal and (ii) diverse gut fermenters engaged in the fermentation of these constituents produce products that can be utilized by earthworms. IMPORTANCE Animal health is linked to gut ecosystems whose primary function is normally the digestion of dietary matter. Earthworms are representative of one of the oldest known animal lineages and, despite their primitive nature, have unique environmental impact by virtue of their dietary consumption of their habitat, i.e., soil-associated matter. A resident gut community is a hallmark of many gut ecosystems of evolutionarily more advanced animals, but the alimentary canal of earthworms is dominated by ingested transient soil microbes. Protein and RNA are (i) the primary organic components of microbial cells that are subject to lysis during gut passage and (ii) fermentable dietary substrates in the alimentary canal. This study examined the gut-associated fermentation of constituents of these biopolymers to determine how their fermentation is integrated to the microbiological dynamics of the gut and might contribute to earthworm-linked transformations of organic matter in the terrestrial biosphere.
Collapse
|
127
|
Riva A, Kuzyk O, Forsberg E, Siuzdak G, Pfann C, Herbold C, Daims H, Loy A, Warth B, Berry D. A fiber-deprived diet disturbs the fine-scale spatial architecture of the murine colon microbiome. Nat Commun 2019; 10:4366. [PMID: 31554820 PMCID: PMC6761162 DOI: 10.1038/s41467-019-12413-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 08/28/2019] [Indexed: 12/20/2022] Open
Abstract
Compartmentalization of the gut microbiota is thought to be important to system function, but the extent of spatial organization in the gut ecosystem remains poorly understood. Here, we profile the murine colonic microbiota along longitudinal and lateral axes using laser capture microdissection. We found fine-scale spatial structuring of the microbiota marked by gradients in composition and diversity along the length of the colon. Privation of fiber reduces the diversity of the microbiota and disrupts longitudinal and lateral gradients in microbiota composition. Both mucus-adjacent and luminal communities are influenced by the absence of dietary fiber, with the loss of a characteristic distal colon microbiota and a reduction in the mucosa-adjacent community, concomitant with depletion of the mucus layer. These results indicate that diet has not only global but also local effects on the composition of the gut microbiota, which may affect function and resilience differently depending on location. Here, employing laser capture microdissection and omics, the authors determine the effects of fiber-deprived diet on the spatial structure of the murine colon microbiome, finding that the absence of dietary fiber and polysaccharides leads to local changes along the colon and deterioration of the mucus layer.
Collapse
Affiliation(s)
- Alessandra Riva
- Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Orest Kuzyk
- Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Erica Forsberg
- The Scripps Research Institute, Scripps Center for Metabolomics and Mass Spectrometry, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.,Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA, 92182, USA
| | - Gary Siuzdak
- The Scripps Research Institute, Scripps Center for Metabolomics and Mass Spectrometry, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Carina Pfann
- Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Craig Herbold
- Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Holger Daims
- Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Alexander Loy
- Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Benedikt Warth
- The Scripps Research Institute, Scripps Center for Metabolomics and Mass Spectrometry, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.,Department of Food Chemistry and Toxicology, University of Vienna, Währingerstraße 38, Vienna, Austria
| | - David Berry
- Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria. .,Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna, Vienna, Austria.
| |
Collapse
|
128
|
Citrobacter rodentium-host-microbiota interactions: immunity, bioenergetics and metabolism. Nat Rev Microbiol 2019; 17:701-715. [PMID: 31541196 DOI: 10.1038/s41579-019-0252-z] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2019] [Indexed: 12/26/2022]
Abstract
Citrobacter rodentium is an extracellular enteric mouse-specific pathogen used to model infections with human pathogenic Escherichia coli and inflammatory bowel disease. C. rodentium injects type III secretion system effectors into intestinal epithelial cells (IECs) to target inflammatory, metabolic and cell survival pathways and establish infection. While the host responds to infection by activating innate and adaptive immune signalling, required for clearance, the IECs respond by rapidly shifting bioenergetics to aerobic glycolysis, which leads to oxygenation of the epithelium, an instant expansion of mucosal-associated commensal Enterobacteriaceae and a decline of obligate anaerobes. Moreover, infected IECs reprogramme intracellular metabolic pathways, characterized by simultaneous activation of cholesterol biogenesis, import and efflux, leading to increased serum and faecal cholesterol levels. In this Review we summarize recent advances highlighting the intimate relationship between C. rodentium pathogenesis, metabolism and the gut microbiota.
Collapse
|
129
|
Capo F, Wilson A, Di Cara F. The Intestine of Drosophila melanogaster: An Emerging Versatile Model System to Study Intestinal Epithelial Homeostasis and Host-Microbial Interactions in Humans. Microorganisms 2019; 7:microorganisms7090336. [PMID: 31505811 PMCID: PMC6780840 DOI: 10.3390/microorganisms7090336] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/16/2019] [Accepted: 09/03/2019] [Indexed: 12/31/2022] Open
Abstract
In all metazoans, the intestinal tract is an essential organ to integrate nutritional signaling, hormonal cues and immunometabolic networks. The dysregulation of intestinal epithelium functions can impact organism physiology and, in humans, leads to devastating and complex diseases, such as inflammatory bowel diseases, intestinal cancers, and obesity. Two decades ago, the discovery of an immune response in the intestine of the genetic model system, Drosophila melanogaster, sparked interest in using this model organism to dissect the mechanisms that govern gut (patho) physiology in humans. In 2007, the finding of the intestinal stem cell lineage, followed by the development of tools available for its manipulation in vivo, helped to elucidate the structural organization and functions of the fly intestine and its similarity with mammalian gastrointestinal systems. To date, studies of the Drosophila gut have already helped to shed light on a broad range of biological questions regarding stem cells and their niches, interorgan communication, immunity and immunometabolism, making the Drosophila a promising model organism for human enteric studies. This review summarizes our current knowledge of the structure and functions of the Drosophila melanogaster intestine, asserting its validity as an emerging model system to study gut physiology, regeneration, immune defenses and host-microbiota interactions.
Collapse
Affiliation(s)
- Florence Capo
- Department of Microbiology and Immunology, IWK Research Centre, Dalhousie University, 5850/5980 University Avenue, Halifax, NS B3K 6R8, Canada.
| | - Alexa Wilson
- Department of Microbiology and Immunology, IWK Research Centre, Dalhousie University, 5850/5980 University Avenue, Halifax, NS B3K 6R8, Canada.
| | - Francesca Di Cara
- Department of Microbiology and Immunology, IWK Research Centre, Dalhousie University, 5850/5980 University Avenue, Halifax, NS B3K 6R8, Canada.
| |
Collapse
|
130
|
Lu Z, Imlay JA. A conserved motif liganding the [4Fe-4S] cluster in [4Fe-4S] fumarases prevents irreversible inactivation of the enzyme during hydrogen peroxide stress. Redox Biol 2019; 26:101296. [PMID: 31465957 PMCID: PMC6831887 DOI: 10.1016/j.redox.2019.101296] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 08/04/2019] [Accepted: 08/07/2019] [Indexed: 11/16/2022] Open
Abstract
Organisms have evolved two different classes of the ubiquitous enzyme fumarase: the [4Fe–4S] cluster-containing class I enzymes are oxidant-sensitive, whereas the class II enzymes are iron-free and therefore oxidant-resistant. When hydrogen peroxide (H2O2) attacks the most-studied [4Fe–4S] fumarases, only the cluster is damaged, and thus the cell can rapidly repair the enzyme. However, this study shows that when elevated levels of H2O2 oxidized the class I fumarase of the obligate anaerobe Bacteroides thetaiotaomicron (Bt-Fum), a hydroxyl-like radical species was produced that caused irreversible covalent damage to the polypeptide. Unlike the fumarase of oxygen-tolerant bacteria, Bt-Fum lacks a key cysteine residue in the typical “CXnCX2C″ motif that ligands [4Fe–4S] clusters. Consequently H2O2 can access and oxidize an iron atom other than the catalytic one in its cluster. Phylogenetic analysis showed that certain clades of bacteria may have evolved the full “CXnCX2C″ motif to shield the [4Fe–4S] cluster of fumarase. This effect was reproduced by the construction of a chimeric enzyme. These data demonstrate the irreversible oxidation of Fe–S cluster enzymes and may recapitulate evolutionary steps that occurred when microorganisms originally confronted oxidizing environments. It is also suggested that, if H2O2 is generated within the colon as a consequence of inflammation or the action of lactic acid bacteria, the inactivation of fumarase could potentially impair the central fermentation pathway of Bacteroides species and contribute to gut dysbiosis.
Collapse
Affiliation(s)
- Zheng Lu
- Department of Biology, Guangdong Provincial Key Laboratory of Marine Biotechnology, STU-UNIVPM Joint Algal Research Center, Shantou University, Shantou, 515063, China.
| | - James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave., Urbana, IL, 61801, USA
| |
Collapse
|
131
|
Imlay JA, Sethu R, Rohaun SK. Evolutionary adaptations that enable enzymes to tolerate oxidative stress. Free Radic Biol Med 2019; 140:4-13. [PMID: 30735836 PMCID: PMC6684875 DOI: 10.1016/j.freeradbiomed.2019.01.048] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 01/31/2019] [Indexed: 10/27/2022]
Abstract
Biochemical mechanisms emerged and were integrated into the metabolic plan of cellular life long before molecular oxygen accumulated in the biosphere. When oxygen levels finaly rose, they threatened specific types of enzymes: those that use organic radicals as catalysts, and those that depend upon iron centers. Nature has found ways to ensure that such enzymes are still used by contemporary organisms. In some cases they are restricted to microbes that reside in anoxic habitats, but in others they manage to function inside aerobic cells. In the latter case, it is frequently true that the ancestral enzyme has been modified to fend off poisoning. In this review we survey a range of protein adaptations that permit radical-based and low-potential iron chemistry to succeed in oxic environments. In many cases, accessory domains shield the vulnerable radical or metal center from oxygen. In others, the structures of iron cofactors evolved to less oxidizable forms, or alternative metals replaced iron altogether. The overarching view is that some classes of biochemical mechanism are intrinsically incompatible with the presence of oxygen. The structural modification of target enzymes is an under-recognized response to this problem.
Collapse
Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA.
| | - Ramakrishnan Sethu
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
| | - Sanjay Kumar Rohaun
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
| |
Collapse
|
132
|
Metabolism, bioenergetics and thermal physiology: influences of the human intestinal microbiota. Nutr Res Rev 2019; 32:205-217. [PMID: 31258100 DOI: 10.1017/s0954422419000076] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The micro-organisms which inhabit the human gut (i.e. the intestinal microbiota) influence numerous human biochemical pathways and physiological functions. The present review focuses on two questions, 'Are intestinal microbiota effects measurable and meaningful?' and 'What research methods and variables are influenced by intestinal microbiota effects?'. These questions are considered with respect to doubly labelled water measurements of energy expenditure, heat balance calculations and models, measurements of RMR via indirect calorimetry, and diet-induced energy expenditure. Several lines of evidence suggest that the intestinal microbiota introduces measurement variability and measurement errors which have been overlooked in research studies involving nutrition, bioenergetics, physiology and temperature regulation. Therefore, we recommend that present conceptual models and research techniques be updated via future experiments, to account for the metabolic processes and regulatory influences of the intestinal microbiota.
Collapse
|
133
|
Kim E, Li J, Kang M, Kelly DL, Chen S, Napolitano A, Panzella L, Shi X, Yan K, Wu S, Shen J, Bentley WE, Payne GF. Redox Is a Global Biodevice Information Processing Modality. PROCEEDINGS OF THE IEEE. INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS 2019; 107:1402-1424. [PMID: 32095023 PMCID: PMC7036710 DOI: 10.1109/jproc.2019.2908582] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Biology is well-known for its ability to communicate through (i) molecularly-specific signaling modalities and (ii) a globally-acting electrical modality associated with ion flow across biological membranes. Emerging research suggests that biology uses a third type of communication modality associated with a flow of electrons through reduction/oxidation (redox) reactions. This redox signaling modality appears to act globally and has features of both molecular and electrical modalities: since free electrons do not exist in aqueous solution, the electrons must flow through molecular intermediates that can be switched between two states - with electrons (reduced) or without electrons (oxidized). Importantly, this global redox modality is easily accessible through its electrical features using convenient electrochemical instrumentation. In this review, we explain this redox modality, describe our electrochemical measurements, and provide four examples demonstrating that redox enables communication between biology and electronics. The first two examples illustrate how redox probing can acquire biologically relevant information. The last two examples illustrate how redox inputs can transduce biologically-relevant transitions for patterning and the induction of a synbio transceiver for two-hop molecular communication. In summary, we believe redox provides a unique ability to bridge bio-device communication because simple electrochemical methods enable global access to biologically meaningful information. Further, we envision that redox may facilitate the application of information theory to the biological sciences.
Collapse
Affiliation(s)
- Eunkyoung Kim
- Institute for Bioscience & Biotechnology Research, University of Maryland, College Park, MD 20742, USA
| | - Jinyang Li
- Institute for Bioscience & Biotechnology Research, Fischell Department of Bioengineering University of Maryland, College Park, MD 20742, USA
| | - Mijeong Kang
- Institute for Bioscience & Biotechnology Research, University of Maryland, College Park, MD 20742, USA
| | - Deanna L Kelly
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD 21228, USA
| | - Shuo Chen
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD 21228, USA
| | - Alessandra Napolitano
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, I-80126 Naples, Italy
| | - Lucia Panzella
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, I-80126 Naples, Italy
| | - Xiaowen Shi
- School of Resource and Environmental Science, Hubei Biomass-Resource Chemistry, Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan 430079, China
| | - Kun Yan
- School of Resource and Environmental Science, Hubei Biomass-Resource Chemistry, Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan 430079, China
| | - Si Wu
- School of Resource and Environmental Science, Hubei Biomass-Resource Chemistry, Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan 430079, China
| | - Jana Shen
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA
| | - William E Bentley
- Institute for Bioscience & Biotechnology Research, Fischell Department of Bioengineering University of Maryland, College Park, MD 20742, USA
| | - Gregory F Payne
- Institute for Bioscience & Biotechnology Research, University of Maryland, College Park, MD 20742, USA
| |
Collapse
|
134
|
Vissenaekens H, Grootaert C, Rajkovic A, Van De Wiele T, Calatayud M. The response of five intestinal cell lines to anoxic conditionsin vitro. Biol Cell 2019; 111:232-244. [DOI: 10.1111/boc.201800076] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 03/22/2019] [Accepted: 05/19/2019] [Indexed: 12/15/2022]
Affiliation(s)
- Hanne Vissenaekens
- Department of Food technologySafety and HealthFaculty of Bioscience EngineeringGhent University Ghent 9000 Belgium
| | - Charlotte Grootaert
- Department of Food technologySafety and HealthFaculty of Bioscience EngineeringGhent University Ghent 9000 Belgium
| | - Andreja Rajkovic
- Department of Food technologySafety and HealthFaculty of Bioscience EngineeringGhent University Ghent 9000 Belgium
| | - Tom Van De Wiele
- Center for Microbial Ecology and Technology (CMET)Faculty of Bioscience EngineeringGhent University Ghent 9000 Belgium
| | - Marta Calatayud
- Center for Microbial Ecology and Technology (CMET)Faculty of Bioscience EngineeringGhent University Ghent 9000 Belgium
| |
Collapse
|
135
|
Del Borrello S, Lautens M, Dolan K, Tan JH, Davie T, Schertzberg MR, Spensley MA, Caudy AA, Fraser AG. Rhodoquinone biosynthesis in C. elegans requires precursors generated by the kynurenine pathway. eLife 2019; 8:e48165. [PMID: 31232688 PMCID: PMC6656428 DOI: 10.7554/elife.48165] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 06/22/2019] [Indexed: 02/05/2023] Open
Abstract
Parasitic helminths infect over a billion humans. To survive in the low oxygen environment of their hosts, these parasites use unusual anaerobic metabolism - this requires rhodoquinone (RQ), an electron carrier that is made by very few animal species. Crucially RQ is not made or used by any parasitic hosts and RQ synthesis is thus an ideal target for anthelmintics. However, little is known about how RQ is made and no drugs are known to block RQ synthesis. C. elegans makes RQ and can use RQ-dependent metabolic pathways - here, we use C. elegans genetics to show that tryptophan degradation via the kynurenine pathway is required to generate the key amine-containing precursors for RQ synthesis. We show that C. elegans requires RQ for survival in hypoxic conditions and, finally, we establish a high throughput assay for drugs that block RQ-dependent metabolism. This may drive the development of a new class of anthelmintic drugs. This study is a key first step in understanding how RQ is made in parasitic helminths.
Collapse
Affiliation(s)
| | | | | | - June H Tan
- The Donnelly CentreUniversity of TorontoTorontoCanada
| | - Taylor Davie
- The Donnelly CentreUniversity of TorontoTorontoCanada
| | | | - Mark A Spensley
- The Donnelly CentreUniversity of TorontoTorontoCanada
- Whole Animal PhenotypingPhenalysys IncTorontoCanada
| | - Amy A Caudy
- The Donnelly CentreUniversity of TorontoTorontoCanada
| | | |
Collapse
|
136
|
Maslowski KM. Metabolism at the centre of the host-microbe relationship. Clin Exp Immunol 2019; 197:193-204. [PMID: 31107965 PMCID: PMC6642865 DOI: 10.1111/cei.13329] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2019] [Indexed: 12/13/2022] Open
Abstract
Maintaining homoeostatic host–microbe interactions is vital for host immune function. The gut microbiota shapes the host immune system and the immune system reciprocally shapes and modifies the gut microbiota. However, our understanding of how these microbes are tolerated and how individual, or communities of, gut microbes influence host function is limited. This review will focus on metabolites as key mediators of this complex host–microbe relationship. It will look at the central role of epithelial metabolism in shaping the gut microbiota, how microbial metabolites influence the epithelium and the mucosal and peripheral immune system, and how the immune system shapes microbial composition and metabolism. Finally, this review will look at how metabolites are involved in cross‐talk between different members of the microbiota and their role during infections.
Collapse
Affiliation(s)
- K M Maslowski
- Institute of Immunology and Immunotherapy and Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| |
Collapse
|
137
|
The σBsignalling activation pathway in the enteropathogenClostridioides difficile. Environ Microbiol 2019; 21:2852-2870. [DOI: 10.1111/1462-2920.14642] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/16/2019] [Accepted: 04/24/2019] [Indexed: 01/05/2023]
|
138
|
Rivera KR, Yokus MA, Erb PD, Pozdin VA, Daniele M. Measuring and regulating oxygen levels in microphysiological systems: design, material, and sensor considerations. Analyst 2019; 144:3190-3215. [PMID: 30968094 PMCID: PMC6564678 DOI: 10.1039/c8an02201a] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
As microfabrication techniques and tissue engineering methods improve, microphysiological systems (MPS) are being engineered that recapitulate complex physiological and pathophysiological states to supplement and challenge traditional animal models. Although MPS provide unique microenvironments that transcend common 2D cell culture, without proper regulation of oxygen content, MPS often fail to provide the biomimetic environment necessary to activate and investigate fundamental pathways of cellular metabolism and sub-cellular level. Oxygen exists in the human body in various concentrations and partial pressures; moreover, it fluctuates dramatically depending on fasting, exercise, and sleep patterns. Regulating oxygen content inside MPS necessitates a sensitive biological sensor to quantify oxygen content in real-time. Measuring oxygen in a microdevice is a non-trivial requirement for studies focused on understanding how oxygen impacts cellular processes, including angiogenesis and tumorigenesis. Quantifying oxygen inside a microdevice can be achieved via an array of technologies, with each method having benefits and limitations in terms of sensitivity, limits of detection, and invasiveness that must be considered and optimized. This article will review oxygen physiology in organ systems and offer comparisons of organ-specific MPS that do and do not consider oxygen microenvironments. Materials used in microphysiological models will also be analyzed in terms of their ability to control oxygen. Finally, oxygen sensor technologies are critically compared and evaluated for use in MPS.
Collapse
Affiliation(s)
- Kristina R Rivera
- Joint Department of Biomedical Engineering, North Carolina State University and University of North Carolina at Chapel Hill, 911 Oval Dr., Raleigh, NC 27695, USA.
| | | | | | | | | |
Collapse
|
139
|
Babaei P, Shoaie S, Ji B, Nielsen J. Challenges in modeling the human gut microbiome. Nat Biotechnol 2019; 36:682-686. [PMID: 30080831 DOI: 10.1038/nbt.4213] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Parizad Babaei
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Saeed Shoaie
- Centre for Host-Microbiome Interactions, Dental Institute, King's College London, London, UK
| | - Boyang Ji
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| |
Collapse
|
140
|
Stairs CW, Kokla A, Ástvaldsson Á, Jerlström-Hultqvist J, Svärd S, Ettema TJG. Oxygen induces the expression of invasion and stress response genes in the anaerobic salmon parasite Spironucleus salmonicida. BMC Biol 2019; 17:19. [PMID: 30823887 PMCID: PMC6397501 DOI: 10.1186/s12915-019-0634-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 02/06/2019] [Indexed: 01/01/2023] Open
Abstract
Background Spironucleus salmonicida is an anaerobic parasite that can cause systemic infections in Atlantic salmon. Unlike other diplomonad parasites, such as the human pathogen Giardia intestinalis, Spironucleus species can infiltrate the blood stream of their hosts eventually colonizing organs, skin and gills. How this presumed anaerobe can persist and invade oxygenated tissues, despite having a strictly anaerobic metabolism, remains elusive. Results To investigate how S. salmonicida response to oxygen stress, we performed RNAseq transcriptomic analyses of cells grown in the presence of oxygen or antioxidant-free medium. We found that over 20% of the transcriptome is differentially regulated in oxygen (1705 genes) and antioxidant-depleted (2280 genes) conditions. These differentially regulated transcripts encode proteins related to anaerobic metabolism, cysteine and Fe-S cluster biosynthesis, as well as a large number of proteins of unknown function. S. salmonicida does not encode genes involved in the classical elements of oxygen metabolism (e.g., catalases, superoxide dismutase, glutathione biosynthesis, oxidative phosphorylation). Instead, we found that genes encoding bacterial-like oxidoreductases were upregulated in response to oxygen stress. Phylogenetic analysis revealed some of these oxygen-responsive genes (e.g., nadh oxidase, rubrerythrin, superoxide reductase) are rare in eukaryotes and likely derived from lateral gene transfer (LGT) events into diplomonads from prokaryotes. Unexpectedly, we observed that many host evasion- and invasion-related genes were also upregulated under oxidative stress suggesting that oxygen might be an important signal for pathogenesis. Conclusion While oxygen is toxic for related organisms, such as G. intestinalis, we find that oxygen is likely a gene induction signal for host invasion- and evasion-related pathways in S. salmonicida. These data provide the first molecular evidence for how S. salmonicida could tolerate oxic host environments and demonstrate how LGT can have a profound impact on the biology of anaerobic parasites. Electronic supplementary material The online version of this article (10.1186/s12915-019-0634-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Courtney W Stairs
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
| | - Anna Kokla
- Present Address: Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), Almas Allé 5, BioCentrum, room D-444, Uppsala, Sweden
| | - Ásgeir Ástvaldsson
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Jon Jerlström-Hultqvist
- Present Address: Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Canada
| | - Staffan Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Thijs J G Ettema
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.,Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Stippeneng 4, 6708WE, Wageningen, The Netherlands
| |
Collapse
|
141
|
Alnajjar KS, Sweasy JB. A new perspective on oxidation of DNA repair proteins and cancer. DNA Repair (Amst) 2019; 76:60-69. [PMID: 30818170 DOI: 10.1016/j.dnarep.2019.02.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/07/2019] [Indexed: 02/07/2023]
Abstract
Reactive oxygen and nitrogen species (RONS) are formed as byproducts of many endogenous cellular processes, in response to infections, and upon exposure to various environmental factors. An increase in RONS can saturate the antioxidation system and leads to oxidative stress. Consequently, macromolecules are targeted for oxidative modifications, including DNA and protein. The oxidation of DNA, which leads to base modification and formation of abasic sites along with single and double strand breaks, has been extensively investigated. Protein oxidation is often neglected and is only recently being recognized as an important regulatory mechanism of various DNA repair proteins. This is a review of the current state of research on the regulation of DNA repair by protein oxidation with emphasis on the correlation between inflammation and cancer.
Collapse
Affiliation(s)
- Khadijeh S Alnajjar
- Department of Therapeutic Radiology and Department of Genetics, Yale University School of Medicine, New Haven, CT, 06520, United States.
| | - Joann B Sweasy
- Department of Therapeutic Radiology and Department of Genetics, Yale University School of Medicine, New Haven, CT, 06520, United States
| |
Collapse
|
142
|
Shin W, Wu A, Massidda MW, Foster C, Thomas N, Lee DW, Koh H, Ju Y, Kim J, Kim HJ. A Robust Longitudinal Co-culture of Obligate Anaerobic Gut Microbiome With Human Intestinal Epithelium in an Anoxic-Oxic Interface-on-a-Chip. Front Bioeng Biotechnol 2019; 7:13. [PMID: 30792981 PMCID: PMC6374617 DOI: 10.3389/fbioe.2019.00013] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 01/18/2019] [Indexed: 01/01/2023] Open
Abstract
The majority of human gut microbiome is comprised of obligate anaerobic bacteria that exert essential metabolic functions in the human colon. These anaerobic gut bacteria constantly crosstalk with the colonic epithelium in a mucosal anoxic-oxic interface (AOI). However, in vitro recreation of the metabolically mismatched colonic AOI has been technically challenging. Furthermore, stable co-culture of the obligate anaerobic commensal microbiome and epithelial cells in a mechanically dynamic condition is essential for demonstrating the host-gut microbiome crosstalk. Here, we developed an anoxic-oxic interface-on-a-chip (AOI Chip) by leveraging a modified human gut-on-a-chip to demonstrate a controlled oxygen gradient in the lumen-capillary transepithelial interface by flowing anoxic and oxic culture medium at various physiological milieus. Computational simulation and experimental results revealed that the presence of the epithelial cell layer and the flow-dependent conditioning in the lumen microchannel is necessary and sufficient to create the steady-state vertical oxygen gradient in the AOI Chip. We confirmed that the created AOI does not compromise the viability, barrier function, mucin production, and the expression and localization of tight junction proteins in the 3D intestinal epithelial layer. Two obligate anaerobic commensal gut microbiome, Bifidobacterium adolescentis and Eubacterium hallii, that exert metabolic cross-feeding in vivo, were independently co-cultured with epithelial cells in the AOI Chip for up to a week without compromising any cell viability. Our new protocol for creating an AOI in a microfluidic gut-on-a-chip may enable to demonstrate the key physiological interactions of obligate anaerobic gut microbiome with the host cells associated with intestinal metabolism, homeostasis, and immune regulation.
Collapse
Affiliation(s)
- Woojung Shin
- Department of Biomedical Engineering, The University of Texas at Austin Austin, TX, United States
| | - Alexander Wu
- Department of Biomedical Engineering, The University of Texas at Austin Austin, TX, United States
| | - Miles W Massidda
- Department of Biomedical Engineering, The University of Texas at Austin Austin, TX, United States
| | - Charles Foster
- Department of Biomedical Engineering, The University of Texas at Austin Austin, TX, United States
| | - Newin Thomas
- Department of Biomedical Engineering, The University of Texas at Austin Austin, TX, United States
| | - Dong-Woo Lee
- Department of Biotechnology, College of Life Science and Technology, Yonsei University, Seoul, South Korea
| | - Hong Koh
- Department of Pediatrics, Severance Fecal Microbiota Transplantation Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Youngwon Ju
- Department of Chemistry, Research Institute for Basic Sciences, Kyung Hee University, Seoul, South Korea
| | - Joohoon Kim
- Department of Chemistry, Research Institute for Basic Sciences, Kyung Hee University, Seoul, South Korea.,KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul, South Korea
| | - Hyun Jung Kim
- Department of Biomedical Engineering, The University of Texas at Austin Austin, TX, United States.,Department of Medical Engineering, Yonsei University College of Medicine, Seoul, South Korea
| |
Collapse
|
143
|
Wen C, Yan W, Sun C, Ji C, Zhou Q, Zhang D, Zheng J, Yang N. The gut microbiota is largely independent of host genetics in regulating fat deposition in chickens. ISME JOURNAL 2019; 13:1422-1436. [PMID: 30728470 DOI: 10.1038/s41396-019-0367-2] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/31/2018] [Accepted: 01/22/2019] [Indexed: 12/12/2022]
Abstract
The gut microbiota has an important role in animal health and performance, but its contribution is difficult to determine, in particular given the effects of host genetic factors. Here, whole-genome sequencing of the hosts and 16S rRNA gene sequencing of the microbiota were performed to separate the effects between host genetics and the microbiota in the duodenum, jejunum, ileum, caecum and faeces on fat deposition in 206 yellow broilers reared under identical conditions. Despite the notable spatial variation in the diversity, composition and potential function of the gut microbiota, host genetics exerted limited effects on the gut microbial community. The duodenal and caecal microbiota made greater contributions to fat deposition and could separately account for 24% and 21% of the variance in the abdominal fat mass after correcting for host genetic effects. We further identified two caecal microbial taxa, Methanobrevibacter and Mucispirillum schaedleri, which were significantly correlated with fat deposition. Chickens with a lower Methanobrevibacter abundance had significantly lower abdominal fat content than those with a higher abundance of Methanobrevibacter (35.51 vs. 55.59 g), and the body weights of these chickens did not notably differ. Chickens with a higher M. schaedleri abundance exhibited lower abdominal fat accumulation (39.88 vs. 55.06 g) and body weight (2.23 vs. 2.41 kg) than those with a lower abundance of this species. These findings may aid the development of strategies for altering the gut microbiota to control fat deposition during broiler production.
Collapse
Affiliation(s)
- Chaoliang Wen
- National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Wei Yan
- National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Congjiao Sun
- National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Congliang Ji
- Guangdong Wen's Nanfang Poultry Breeding Co. Ltd, Xinxing, 527400, Guangdong Province, China
| | - Qianqian Zhou
- National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Dexiang Zhang
- Guangdong Wen's Nanfang Poultry Breeding Co. Ltd, Xinxing, 527400, Guangdong Province, China
| | - Jiangxia Zheng
- National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China.
| | - Ning Yang
- National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China.
| |
Collapse
|
144
|
Feeding Rapidly Alters Microbiome Composition and Gene Transcription in the Clownfish Gut. Appl Environ Microbiol 2019; 85:AEM.02479-18. [PMID: 30446559 DOI: 10.1128/aem.02479-18] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/10/2018] [Indexed: 12/13/2022] Open
Abstract
Diet is a major determinant of intestinal microbiome composition. While studies have evaluated microbiome responses to diet variation, less is understood about how the act of feeding influences the microbiome, independent of diet type. Here, we use the clownfish Premnas biaculeatus, a species reared commonly in ornamental marine aquaculture, to test how the diversity, predicted gene content, and gene transcription of the microbiome vary over a 2-day diurnal period with a single daily feeding event. This study used fish fed four times daily, once daily, or every 3 days prior to the diurnal period, allowing us also to test how feeding frequency affected microbiome diversity. The amount of time between feedings had no effect on baseline diversity of the microbiome. In contrast, the act of feeding itself caused a significant short-term change in the microbiome, with microbiome diversity, predicted gene content, and gene transcription varying significantly between time points immediately before and 1.5 hours postfeeding. Variation was driven by abundance shifts involving exact sequence variants (ESVs), with one ESV identified as Photobacterium sp. increasing from <0.5% of sequences immediately prefeeding to 34% at 1.5 h postfeeding. Other ESVs from a range of microbial groups also increased dramatically after feeding, with the majority also detected in the food. One ESV identified as Clostridium perfringens represented up to 55% of sequences but did not vary significantly over the diurnal period and was not detected in the food. Postfeeding samples were enriched in transcripts and predicted genes for social interactions, cell motility, and coping with foreign DNA, whereas time points farther from feeding were enriched in genes of diverse catabolic and biosynthetic functions. These results confirm feeding as a significant destabilizing force in clownfish intestinal microbiomes, likely due to both input of cells attached to food and stimulation of resident microbes. Microbes such as Photobacterium may episodically transition from environmental reservoirs to growth in the gut, likely in association with food particles. This transition may be facilitated by functions for navigating a new environment and interacting with neighboring microbes and host cells. Other taxa, such as Clostridium, are comparatively stable intestinal members and less likely to be affected by passing food. Conclusions about microbiome ecology may therefore differ based on when samples were collected relative to the last feeding.IMPORTANCE Despite extensive study of intestinal microbiome diversity and the role of diet type in structuring gut microbial communities, we know very little about short-term changes in the intestinal microbiome as a result of feeding alone. Sampling microbiomes over a feeding cycle will allow us to differentiate opportunistic, feeding-responsive microbes from resident, potentially commensal members of the gut community. Also, since feeding has the potential to alter microbiome structure, sampling at different points relative to the last feeding event will likely yield different conclusions about microbiome composition and function. This variation should be addressed in comparative microbiome studies. Our study contributes to knowledge of short-term changes in the gut microbiome associated with feeding events.
Collapse
|
145
|
Costless metabolic secretions as drivers of interspecies interactions in microbial ecosystems. Nat Commun 2019; 10:103. [PMID: 30626871 PMCID: PMC6327061 DOI: 10.1038/s41467-018-07946-9] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 12/06/2018] [Indexed: 01/21/2023] Open
Abstract
Metabolic exchange mediates interactions among microbes, helping explain diversity in microbial communities. As these interactions often involve a fitness cost, it is unclear how stable cooperation can emerge. Here we use genome-scale metabolic models to investigate whether the release of “costless” metabolites (i.e. those that cause no fitness cost to the producer), can be a prominent driver of intermicrobial interactions. By performing over 2 million pairwise growth simulations of 24 species in a combinatorial assortment of environments, we identify a large space of metabolites that can be secreted without cost, thus generating ample cross-feeding opportunities. In addition to providing an atlas of putative interactions, we show that anoxic conditions can promote mutualisms by providing more opportunities for exchange of costless metabolites, resulting in an overrepresentation of stable ecological network motifs. These results may help identify interaction patterns in natural communities and inform the design of synthetic microbial consortia. In considering cross-feeding among microbes within communities, it is typically assumed that metabolic secretions are costly to produce. However, Pacheco et al. use metabolic models to show that ‘costless’ secretions could be common in some environments and important for structuring interactions among microbes.
Collapse
|
146
|
Sardelli L, Pacheco DP, Ziccarelli A, Tunesi M, Caspani O, Fusari A, Briatico Vangosa F, Giordano C, Petrini P. Towards bioinspired in vitro models of intestinal mucus. RSC Adv 2019; 9:15887-15899. [PMID: 35521409 PMCID: PMC9064393 DOI: 10.1039/c9ra02368b] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/09/2019] [Indexed: 12/22/2022] Open
Abstract
Intestinal mucus is a biological structure that acts as a barrier between the external environment and the epithelium. It actively selects nutrient and drug intake, regulates the symbiosis with the intestinal microbiota and keeps the epithelium protected from the attack of pathogens. All these functions are closely connected to the chemical and structural complexity of this biological material, on which its viscoelastic and diffusive properties depend. Many models have been proposed to replicate these characteristics using glycoproteins in solution and possibly the addition of other mucus components, such as lipids and other proteins. In the field of mucus modelling, an overall view of the mucus as a material, having its own viscous, rheological and diffusive characteristics, has been undersized with respect to a pure biological-functional analysis. In this review, we propose a description of the mucus as a biomaterial, including a presentation of its chemical and structural complexity, and of its main viscoelastic-diffusive properties, in order to provide a synthesis of the characteristics necessary for the engineering of more advanced mucus models. Intestinal mucus is an anisotropic biological structure that acts as a barrier between the external environment and the epithelium.![]()
Collapse
Affiliation(s)
- Lorenzo Sardelli
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”
- Politecnico di Milano
- Milan
- Italy
| | - Daniela Peneda Pacheco
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”
- Politecnico di Milano
- Milan
- Italy
| | - Anna Ziccarelli
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”
- Politecnico di Milano
- Milan
- Italy
| | - Marta Tunesi
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”
- Politecnico di Milano
- Milan
- Italy
| | - Omar Caspani
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”
- Politecnico di Milano
- Milan
- Italy
| | - Andrea Fusari
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”
- Politecnico di Milano
- Milan
- Italy
| | - Francesco Briatico Vangosa
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”
- Politecnico di Milano
- Milan
- Italy
| | - Carmen Giordano
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”
- Politecnico di Milano
- Milan
- Italy
| | - Paola Petrini
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”
- Politecnico di Milano
- Milan
- Italy
| |
Collapse
|
147
|
Kim K, Golubeva YA, Vanderpool CK, Slauch JM. Oxygen-dependent regulation of SPI1 type three secretion system by small RNAs in Salmonella enterica serovar Typhimurium. Mol Microbiol 2018; 111:570-587. [PMID: 30484918 DOI: 10.1111/mmi.14174] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2018] [Indexed: 01/31/2023]
Abstract
Salmonella Typhimurium induces inflammatory diarrhea and uptake into intestinal epithelial cells using the Salmonella pathogenicity island 1 (SPI1) type III secretion system (T3SS). Three AraC-like regulators, HilD, HilC and RtsA, form a feed-forward regulatory loop that activates transcription of hilA, encoding the activator of the T3SS structural genes. Many environmental signals and regulatory systems are integrated into this circuit to precisely regulate SPI1 expression. A subset of these regulatory factors affects translation of hilD, but the mechanisms are poorly understood. Here, we identified two sRNAs, FnrS and ArcZ, which repress hilD translation, leading to decreased production of HilA. FnrS and ArcZ are oppositely regulated in response to oxygen, one of the key environmental signals affecting expression of SPI1. Mutational analysis demonstrates that FnrS and ArcZ bind to the hilD mRNA 5' UTR, resulting in translational repression. Deletion of fnrS led to increased HilD production under low-aeration conditions, whereas deletion of arcZ abolished the regulatory effect on hilD translation aerobically. The fnrS arcZ double mutant has phenotypes in a mouse oral infection model consistent with increased expression of SPI1. Together, these results suggest that coordinated regulation by these two sRNAs maximizes HilD production at an intermediate level of oxygen.
Collapse
Affiliation(s)
- Kyungsub Kim
- Department of Microbiology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
| | - Yekaterina A Golubeva
- Department of Microbiology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
| | - Carin K Vanderpool
- Department of Microbiology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
| | - James M Slauch
- Department of Microbiology, University of Illinois at Urbana-Champaign, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
| |
Collapse
|
148
|
Bin P, Tang Z, Liu S, Chen S, Xia Y, Liu J, Wu H, Zhu G. Intestinal microbiota mediates Enterotoxigenic Escherichia coli-induced diarrhea in piglets. BMC Vet Res 2018; 14:385. [PMID: 30518356 PMCID: PMC6282381 DOI: 10.1186/s12917-018-1704-9] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 11/21/2018] [Indexed: 12/31/2022] Open
Abstract
Background Enterotoxigenic Escherichia coli (ETEC) causes diarrhea in humans, cows, and pigs. The gut microbiota underlies pathology of several infectious diseases yet the role of the gut microbiota in the pathogenesis of ETEC-induced diarrhea is unknown. Results By using an ETEC induced diarrheal model in piglet, we profiled the jejunal and fecal microbiota using metagenomics and 16S rRNA sequencing. A jejunal microbiota transplantation experiment was conducted to determine the role of the gut microbiota in ETEC-induced diarrhea. ETEC-induced diarrhea influenced the structure and function of gut microbiota. Diarrheal piglets had lower Bacteroidetes: Firmicutes ratio and microbiota diversity in the jejunum and feces, and lower percentage of Prevotella in the feces, but higher Lactococcus in the jejunum and higher Escherichia-Shigella in the feces. The transplantation of the jejunal microbiota from diarrheal piglets to uninfected piglets leaded to diarrhea after transplantation. Microbiota transplantation experiments also supported the notion that dysbiosis of gut microbiota is involved in the immune responses in ETEC-induced diarrhea. Conclusion We conclude that ETEC infection influences the gut microbiota and the dysbiosis of gut microbiota after ETEC infection mediates the immune responses in ETEC infection. Electronic supplementary material The online version of this article (10.1186/s12917-018-1704-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Peng Bin
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Jiangsu Co-innovation Center for Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Zhiyi Tang
- College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Shaojuan Liu
- College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Shuai Chen
- Laboratory of Animal Nutrition and Health and Key Laboratory of Agro-Ecology, Institute of Subtropical Agriculture, The Chinese Academy of Sciences, Changsha, Hunan, 410125, People's Republic of China
| | - Yaoyao Xia
- Laboratory of Animal Nutrition and Health and Key Laboratory of Agro-Ecology, Institute of Subtropical Agriculture, The Chinese Academy of Sciences, Changsha, Hunan, 410125, People's Republic of China
| | - Jiaqi Liu
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Jiangsu Co-innovation Center for Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Hucong Wu
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Jiangsu Co-innovation Center for Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Guoqiang Zhu
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Jiangsu Co-innovation Center for Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China.
| |
Collapse
|
149
|
Imlay JA. Where in the world do bacteria experience oxidative stress? Environ Microbiol 2018; 21:521-530. [PMID: 30307099 DOI: 10.1111/1462-2920.14445] [Citation(s) in RCA: 174] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/02/2018] [Accepted: 10/07/2018] [Indexed: 11/26/2022]
Abstract
Reactive oxygen species - superoxide, hydrogen peroxide and hydroxyl radicals - have long been suspected of constraining bacterial growth in important microbial habitats and indeed of shaping microbial communities. Over recent decades, studies of paradigmatic organisms such as Escherichia coli, Salmonella typhimurium, Bacillus subtilis and Saccharomyces cerevisiae have pinpointed the biomolecules that oxidants can damage and the strategies by which microbes minimize their injuries. What is lacking is a good sense of the circumstances under which oxidative stress actually occurs. In this MiniReview several potential natural sources of oxidative stress are considered: endogenous ROS formation, chemical oxidation of reduced species at oxic-anoxic interfaces, H2 O2 production by lactic acid bacteria, the oxidative burst of phagocytes and the redox-cycling of secreted small molecules. While all of these phenomena can be reproduced and verified in the lab, the actual quantification of stress in natural habitats remains lacking - and, therefore, we have a fundamental hole in our understanding of the role that oxidative stress actually plays in the biosphere.
Collapse
Affiliation(s)
- James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
| |
Collapse
|
150
|
Modulation of Enterohaemorrhagic Escherichia coli Survival and Virulence in the Human Gastrointestinal Tract. Microorganisms 2018; 6:microorganisms6040115. [PMID: 30463258 PMCID: PMC6313751 DOI: 10.3390/microorganisms6040115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/16/2018] [Accepted: 11/18/2018] [Indexed: 01/05/2023] Open
Abstract
Enterohaemorrhagic Escherichia coli (EHEC) is a major foodborne pathogen responsible for human diseases ranging from diarrhoea to life-threatening complications. Survival of the pathogen and modulation of virulence gene expression along the human gastrointestinal tract (GIT) are key features in bacterial pathogenesis, but remain poorly described, due to a paucity of relevant model systems. This review will provide an overview of the in vitro and in vivo studies investigating the effect of abiotic (e.g., gastric acid, bile, low oxygen concentration or fluid shear) and biotic (e.g., gut microbiota, short chain fatty acids or host hormones) parameters of the human gut on EHEC survival and/or virulence (especially in relation with motility, adhesion and toxin production). Despite their relevance, these studies display important limitations considering the complexity of the human digestive environment. These include the evaluation of only one single digestive parameter at a time, lack of dynamic flux and compartmentalization, and the absence of a complex human gut microbiota. In a last part of the review, we will discuss how dynamic multi-compartmental in vitro models of the human gut represent a novel platform for elucidating spatial and temporal modulation of EHEC survival and virulence along the GIT, and provide new insights into EHEC pathogenesis.
Collapse
|