1
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Kawasaki M, McConnel CS, Burbick CR, Ambrosini YM. Pathogen-epithelium interactions and inflammatory responses in Salmonella Dublin infections using ileal monolayer models derived from adult bovine organoids. Sci Rep 2024; 14:11479. [PMID: 38769412 DOI: 10.1038/s41598-024-62407-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 05/16/2024] [Indexed: 05/22/2024] Open
Abstract
Salmonella enterica serovar Dublin (S. Dublin) is an important enteric pathogen affecting cattle and poses increasing public health risks. Understanding the pathophysiology and host-pathogen interactions of S. Dublin infection are critical for developing effective control strategies, yet studies are hindered by the lack of physiologically relevant in vitro models. This study aimed to generate a robust ileal monolayer derived from adult bovine organoids, validate its feasibility as an in vitro infection model with S. Dublin, and evaluate the epithelial response to infection. A stable, confluent monolayer with a functional epithelial barrier was established under optimized culture conditions. The model's applicability for studying S. Dublin infection was confirmed by documenting intracellular bacterial invasion and replication, impacts on epithelial integrity, and a specific inflammatory response, providing insights into the pathogen-epithelium interactions. The study underscores the utility of organoid-derived monolayers in advancing our understanding of enteric infections in livestock and highlights implications for therapeutic strategy development and preventive measures, with potential applications extending to both veterinary and human medicine. The established bovine ileal monolayer offers a novel and physiologically relevant in vitro platform for investigating enteric pathogen-host interactions, particularly for pathogens like S. Dublin.
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Affiliation(s)
- Minae Kawasaki
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - Craig S McConnel
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - Claire R Burbick
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - Yoko M Ambrosini
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA.
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2
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Kawasaki M, Ambrosini YM. Differential Colonization and Mucus Ultrastructure Visualization in Bovine Ileal and Rectal Organoid-Derived Monolayers Exposed to Enterohemorrhagic Escherichia coli. Int J Mol Sci 2024; 25:4914. [PMID: 38732126 PMCID: PMC11084217 DOI: 10.3390/ijms25094914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is a critical public health concern due to its role in severe gastrointestinal illnesses in humans, including hemorrhagic colitis and the life-threatening hemolytic uremic syndrome. While highly pathogenic to humans, cattle, the main reservoir for EHEC, often remain asymptomatic carriers, complicating efforts to control its spread. Our study introduces a novel method to investigate EHEC using organoid-derived monolayers from adult bovine ileum and rectum. These polarized epithelial monolayers were exposed to EHEC for four hours, allowing us to perform comparative analyses between the ileal and rectal tissues. Our findings mirrored in vivo observations, showing a higher colonization rate in the rectum compared with the ileum (44.0% vs. 16.5%, p < 0.05). Both tissues exhibited an inflammatory response with increased expression levels of TNF-a (p < 0.05) and a more pronounced increase of IL-8 in the rectum (p < 0.01). Additionally, the impact of EHEC on the mucus barrier varied across these gastrointestinal regions. Innovative visualization techniques helped us study the ultrastructure of mucus, revealing a net-like mucin glycoprotein organization. While further cellular differentiation could enhance model accuracy, our research significantly deepens understanding of EHEC pathogenesis in cattle and informs strategies for the preventative measures and therapeutic interventions.
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Affiliation(s)
| | - Yoko M. Ambrosini
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA;
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3
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Xie X, Tong X, Li Z, Cheng Q, Wang X, Long Y, Liu F, Wang Y, Wang J, Liu L. Use of mouse primary epidermal organoids for USA300 infection modeling and drug screening. Cell Death Dis 2023; 14:15. [PMID: 36631452 PMCID: PMC9833019 DOI: 10.1038/s41419-022-05525-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 12/16/2022] [Accepted: 12/16/2022] [Indexed: 01/13/2023]
Abstract
Skin infections caused by drug-resistant Staphylococcus aureus occur at high rates nationwide. Mouse primary epidermal organoids (mPEOs) possess stratified histological and morphological characteristics of epidermis and are highly similar to their derived tissue at the transcriptomic and proteomic levels. Herein, the susceptibility of mPEOs to methicillin-resistant S. aureus USA300 infection was investigated. The results show that mPEOs support USA300 colonization and invasion, exhibiting swollen epithelial squamous cells with nuclear necrosis and secreting inflammatory factors such as IL-1β. Meanwhile mPEOs beneficial to observe the process of USA300 colonization with increasing infection time, and USA300 induces mPEOs to undergo pyroptosis and autophagy. In addition, we performed a drug screen for the mPEO infection model and showed that vancomycin restores cell viability and inhibits bacterial internalization in a concentration-dependent manner. In conclusion, we establish an in vitro skin infection model that contributes to the examination of drug screening strategies and antimicrobial drug mechanisms.
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Affiliation(s)
- Xiaorui Xie
- School of Pharmacy, Fudan University, Shanghai, China
- Shanghai Drugability Biomass Product Evaluation Professional Public Service Platform, Center for Pharmacological Evaluation and Research, China State Institute of Pharmaceutical Industry, Shanghai, China
| | - Xuebo Tong
- Shanghai Children's Medical Center affiliated to the Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhihong Li
- Shanghai Drugability Biomass Product Evaluation Professional Public Service Platform, Center for Pharmacological Evaluation and Research, China State Institute of Pharmaceutical Industry, Shanghai, China
| | - Quan Cheng
- Shanghai Drugability Biomass Product Evaluation Professional Public Service Platform, Center for Pharmacological Evaluation and Research, China State Institute of Pharmaceutical Industry, Shanghai, China
| | - Xiaowei Wang
- Shanghai Drugability Biomass Product Evaluation Professional Public Service Platform, Center for Pharmacological Evaluation and Research, China State Institute of Pharmaceutical Industry, Shanghai, China
| | - Yin Long
- Department of Traditional Chinese Medicine, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, 710032, China
| | - Fangbo Liu
- Shanghai Drugability Biomass Product Evaluation Professional Public Service Platform, Center for Pharmacological Evaluation and Research, China State Institute of Pharmaceutical Industry, Shanghai, China
| | - Yonghui Wang
- School of Pharmacy, Fudan University, Shanghai, China.
| | - Juan Wang
- Shanghai Drugability Biomass Product Evaluation Professional Public Service Platform, Center for Pharmacological Evaluation and Research, China State Institute of Pharmaceutical Industry, Shanghai, China.
| | - Li Liu
- Shanghai Drugability Biomass Product Evaluation Professional Public Service Platform, Center for Pharmacological Evaluation and Research, China State Institute of Pharmaceutical Industry, Shanghai, China.
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4
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Affiliation(s)
| | - Laura J. Knoll
- University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
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5
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Schwartz FA, Christophersen L, Laulund AS, Lundquist R, Lerche C, Rude Nielsen P, Bundgaard H, Høiby N, Moser C. Novel human in vitro vegetation simulation model for infective endocarditis. APMIS 2021; 129:653-662. [PMID: 34580927 DOI: 10.1111/apm.13182] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 09/09/2021] [Indexed: 01/01/2023]
Abstract
Infective endocarditis (IE) is a heart valve infection with high mortality rates. IE results from epithelial lesions, inducing sterile healing vegetations consisting of platelets, leucocytes, and fibrin that are susceptible for colonization by temporary bacteremia. Clinical testing of new treatments for IE is difficult and fast models sparse. The present study aimed at establishing an in vitro vegetation simulation IE model for fast screening of novel treatment strategies. A healing promoting platelet and leucocyte-rich fibrin patch was used to establish an IE organoid-like model by colonization with IE-associated bacterial isolates Staphylococcus aureus, Streptococcus spp (S. mitis group), and Enterococcus faecalis. The patch was subsequently exposed to tobramycin, ciprofloxacin, or penicillin. Bacterial colonization was evaluated by microscopy and quantitative bacteriology. We achieved stable bacterial colonization on the patch, comparable to clinical IE vegetations. Microscopy revealed uneven, biofilm-like colonization of the patch. The surface-associated bacteria displayed increased tolerance to antibiotics compared to planktonic bacteria. The present study succeeded in establishing an IE simulation model with the relevant pathogens S. aureus, S. mitis group, and E. faecalis. The findings indicate that the IE model mirrors the natural IE process and has the potential for fast screening of treatment candidates.
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Affiliation(s)
| | | | - Anne Sofie Laulund
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen N, Denmark
| | | | - Christian Lerche
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen N, Denmark
| | - Pia Rude Nielsen
- Department of Pathology, Zealand University Hospital, Roskilde, Denmark
| | - Henning Bundgaard
- Department of Cardiology, Copenhagen University Hospital Herlev, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Niels Høiby
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen N, Denmark
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
| | - Claus Moser
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen N, Denmark
- Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark
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6
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Nickerson KP, Llanos-Chea A, Ingano L, Serena G, Miranda-Ribera A, Perlman M, Lima R, Sztein MB, Fasano A, Senger S, Faherty CS. A Versatile Human Intestinal Organoid-Derived Epithelial Monolayer Model for the Study of Enteric Pathogens. Microbiol Spectr 2021; 9:e0000321. [PMID: 34106568 PMCID: PMC8552518 DOI: 10.1128/spectrum.00003-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 04/20/2021] [Indexed: 01/09/2023] Open
Abstract
Gastrointestinal infections cause significant morbidity and mortality worldwide. The complexity of human biology and limited insights into host-specific infection mechanisms are key barriers to current therapeutic development. Here, we demonstrate that two-dimensional epithelial monolayers derived from human intestinal organoids, combined with in vivo-like bacterial culturing conditions, provide significant advancements for the study of enteropathogens. Monolayers from the terminal ileum, cecum, and ascending colon recapitulated the composition of the gastrointestinal epithelium, in which several techniques were used to detect the presence of enterocytes, mucus-producing goblet cells, and other cell types following differentiation. Importantly, the addition of receptor activator of nuclear factor kappa-B ligand (RANKL) increased the presence of M cells, critical antigen-sampling cells often exploited by enteric pathogens. For infections, bacteria were grown under in vivo-like conditions known to induce virulence. Overall, interesting patterns of tissue tropism and clinical manifestations were observed. Shigella flexneri adhered efficiently to the cecum and colon; however, invasion in the colon was best following RANKL treatment. Both Salmonella enterica serovars Typhi and Typhimurium displayed different infection patterns, with S. Typhimurium causing more destruction of the terminal ileum and S. Typhi infecting the cecum more efficiently than the ileum, particularly with regard to adherence. Finally, various pathovars of Escherichia coli validated the model by confirming only adherence was observed with these strains. This work demonstrates that the combination of human-derived tissue with targeted bacterial growth conditions enables powerful analyses of human-specific infections that could lead to important insights into pathogenesis and accelerate future vaccine development. IMPORTANCE While traditional laboratory techniques and animal models have provided valuable knowledge in discerning virulence mechanisms of enteric pathogens, the complexity of the human gastrointestinal tract has hindered our understanding of physiologically relevant, human-specific interactions; and thus, has significantly delayed successful vaccine development. The human intestinal organoid-derived epithelial monolayer (HIODEM) model closely recapitulates the diverse cell populations of the intestine, allowing for the study of human-specific infections. Differentiation conditions permit the expansion of various cell populations, including M cells that are vital to immune recognition and the establishment of infection by some bacteria. We provide details of reproducible culture methods and infection conditions for the analyses of Shigella, Salmonella, and pathogenic Escherichia coli in which tissue tropism and pathogen-specific infection patterns were detected. This system will be vital for future studies that explore infection conditions, health status, or epigenetic differences and will serve as a novel screening platform for therapeutic development.
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Affiliation(s)
- Kourtney P. Nickerson
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Alejandro Llanos-Chea
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Laura Ingano
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Gloria Serena
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Alba Miranda-Ribera
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Meryl Perlman
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Rosiane Lima
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Marcelo B. Sztein
- Center for Vaccine Development and Global Health, Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Alessio Fasano
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Stefania Senger
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Christina S. Faherty
- Mucosal Immunology and Biology Research Center, Division of Pediatric Gastroenterology and Nutrition, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
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7
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Sharma K, Thacker VV, Dhar N, Clapés Cabrer M, Dubois A, Signorino-Gelo F, Mullenders J, Knott GW, Clevers H, McKinney JD. Early invasion of the bladder wall by solitary bacteria protects UPEC from antibiotics and neutrophil swarms in an organoid model. Cell Rep 2021; 36:109351. [PMID: 34289360 DOI: 10.1016/j.celrep.2021.109351] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 03/26/2021] [Accepted: 06/15/2021] [Indexed: 01/24/2023] Open
Abstract
Recurrence of uropathogenic Escherichia coli (UPEC) infections has been attributed to reactivation of quiescent intracellular reservoirs (QIRs) in deep layers of the bladder wall. QIRs are thought to arise late during infection following dispersal of bacteria from intracellular bacterial communities (IBCs) in superficial umbrella cells. Here, we track the formation of QIR-like bacteria in a bladder organoid model that recapitulates the stratified uroepithelium within a volume suitable for high-resolution live-cell imaging. Bacteria injected into the organoid lumen enter umbrella-like cells and proliferate to form IBC-like bodies. In parallel, single bacteria penetrate deeper layers of the organoid wall, where they localize within or between uroepithelial cells. These "solitary" bacteria evade killing by antibiotics and neutrophils and are morphologically distinct from bacteria in IBCs. We conclude that bacteria with QIR-like properties may arise at early stages of infection, independent of IBC formation and rupture.
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Affiliation(s)
- Kunal Sharma
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Vivek V Thacker
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Neeraj Dhar
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Maria Clapés Cabrer
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Anaëlle Dubois
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - François Signorino-Gelo
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Jasper Mullenders
- Oncode Institute, Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center, Utrecht, the Netherlands
| | - Graham W Knott
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Hans Clevers
- Oncode Institute, Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center, Utrecht, the Netherlands
| | - John D McKinney
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015 Lausanne, Switzerland.
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8
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Rosendahl Huber A, Pleguezuelos-Manzano C, Puschhof J. A bacterial mutational footprint in colorectal cancer genomes. Br J Cancer 2021; 124:1751-1753. [PMID: 33742142 PMCID: PMC8144397 DOI: 10.1038/s41416-021-01273-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/06/2021] [Accepted: 01/11/2021] [Indexed: 12/18/2022] Open
Abstract
Changes in the microbiome are associated with the development of colorectal cancer, but causal explanations have been lacking. We recently demonstrated that pks+ Escherichia coli induce a specific mutational pattern using intestinal organoids and these mutations are present in the genomes of colorectal cancer. This finding warrants further studies on the microbial role in oncogenic mutation induction, cancer development and future preventive strategies.
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Affiliation(s)
- Axel Rosendahl Huber
- The Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands.
- Oncode Institute, Hubrecht Institute, Utrecht, The Netherlands.
| | - Cayetano Pleguezuelos-Manzano
- Oncode Institute, Hubrecht Institute, Utrecht, The Netherlands.
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, Utrecht, The Netherlands.
| | - Jens Puschhof
- Oncode Institute, Hubrecht Institute, Utrecht, The Netherlands.
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, Utrecht, The Netherlands.
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9
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Han X, Mslati MA, Davies E, Chen Y, Allaire JM, Vallance BA. Creating a More Perfect Union: Modeling Intestinal Bacteria-Epithelial Interactions Using Organoids. Cell Mol Gastroenterol Hepatol 2021; 12:769-782. [PMID: 33895425 PMCID: PMC8273413 DOI: 10.1016/j.jcmgh.2021.04.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 04/09/2021] [Accepted: 04/12/2021] [Indexed: 02/08/2023]
Abstract
Intestinal organoids have become indispensable tools for many gastrointestinal researchers, advancing their studies of nontransformed intestinal epithelial cells, and their roles in an array of diseases, including inflammatory bowel disease and colon cancer. In many cases. these diseases, as well as many enteric infections, reflect pathogenic interactions between bacteria and the gut epithelium. The complexity of studying this microbe-epithelial interface in vivo has led to significant focus on modeling this cross-talk using organoid models. Considering how quickly the organoid field is advancing, it can be difficult to keep up to date with the latest techniques, as well as their respective strengths and weaknesses. This review addresses the advantages of using organoids derived from adult stem cells and the recently identified differences that biopsy location and patient age can have on organoids and their interactions with microbes. Several approaches to introducing bacteria in a relevant (apical) manner (ie, microinjecting 3-dimensional spheroids, polarity-reversed organoids, and 2-dimensional monolayers) also are addressed, as are the key readouts that can be obtained using these models. Lastly, the potential for new approaches, such as air-liquid interface, to facilitate studying bacterial interactions with important but understudied epithelial subsets such as goblet cells and their products, is evaluated.
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Affiliation(s)
- Xiao Han
- Department of Pediatrics, British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Matthias A Mslati
- Department of Pediatrics, British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Emily Davies
- Department of Pediatrics, British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yan Chen
- Department of Pediatrics, British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Joannie M Allaire
- Department of Pediatrics, British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Bruce A Vallance
- Department of Pediatrics, British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada.
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10
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Wu BC, Haney EF, Akhoundsadegh N, Pletzer D, Trimble MJ, Adriaans AE, Nibbering PH, Hancock REW. Human organoid biofilm model for assessing antibiofilm activity of novel agents. NPJ Biofilms Microbiomes 2021; 7:8. [PMID: 33495449 PMCID: PMC7835231 DOI: 10.1038/s41522-020-00182-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 12/11/2020] [Indexed: 02/08/2023] Open
Abstract
Bacterial biofilms cause 65% of all human infections and are highly resistant to antibiotic therapy but lack specific treatments. To provide a human organoid model for studying host-microbe interplay and enabling screening for novel antibiofilm agents, a human epidermis organoid model with robust methicillin-resistant Staphylococcus aureus (MRSA) USA300 and Pseudomonas aeruginosa PAO1 biofilm was developed. Treatment of 1-day and 3-day MRSA and PAO1 biofilms with antibiofilm peptide DJK-5 significantly and substantially reduced the bacterial burden. This model enabled the screening of synthetic host defense peptides, revealing their superior antibiofilm activity against MRSA compared to the antibiotic mupirocin. The model was extended to evaluate thermally wounded skin infected with MRSA biofilms resulting in increased bacterial load, cytotoxicity, and pro-inflammatory cytokine levels that were all reduced upon treatment with DJK-5. Combination treatment of DJK-5 with an anti-inflammatory peptide, 1002, further reduced cytotoxicity and skin inflammation.
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Affiliation(s)
- Bing Catherine Wu
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Evan F Haney
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Noushin Akhoundsadegh
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Daniel Pletzer
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
- Department of Microbiology and Immunology, University of Otago, Dunedin, Otago, New Zealand
| | - Michael J Trimble
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Alwin E Adriaans
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Peter H Nibbering
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Robert E W Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada.
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11
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Wang X, Wang S, Guo B, Su Y, Tan Z, Chang M, Diao J, Zhao Y, Wang Y. Human primary epidermal organoids enable modeling of dermatophyte infections. Cell Death Dis 2021; 12:35. [PMID: 33414472 PMCID: PMC7790817 DOI: 10.1038/s41419-020-03330-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 11/15/2020] [Accepted: 11/17/2020] [Indexed: 12/12/2022]
Abstract
Technology of generating human epidermal derivatives with physiological relevance to in vivo epidermis is continuously investigated for improving their effects on modeling of human natural dermatological status in basic and clinical studies. Here, we report a method of robust establishment and expansion of human primary epidermal organoids (hPEOs) under a chemically defined condition. hPEOs reconstruct morphological, molecular, and functional features of human epidermis and can expand for 6 weeks. Remarkably, hPEOs are permissive for dermatophyte infections caused by Trichophyton Rubrum (T. rubrum). The T. rubrum infections on hPEOs reflect many aspects of known clinical pathological reactions and reveal that the repression on IL-1 signaling may contribute to chronic and recurrent infections with the slight inflammation caused by T. rubrum in human skin. Thus, our present study provides a new insight into the pathogenesis of T. rubrum infections and indicates that hPEOs are a potential ex vivo model for both basic studies of skin diseases and clinical studies of testing potential antifungal drugs.
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Affiliation(s)
- Xuan Wang
- Translational Medicine Research Center, Beijing Tsinghua Chang Gung Hospital, Beijing, 102218, China
- Department of Stem Cell and Regenerative Medicine, Beijing Institute of Health Service and Transfusion Medicine, Beijing, 100850, China
| | - Shuyong Wang
- Army Tuberculosis Prevention and Control Key Laboratory, Beijing Key Laboratory of New Techniques of Tuberculosis Diagnosis and Treatment, Institute for Tuberculosis Research, the 8th Medical Center of Chinese PLA General Hospital, Beijing, 100091, China
| | - Baolin Guo
- Department of Stem Cell and Regenerative Medicine, Beijing Institute of Health Service and Transfusion Medicine, Beijing, 100850, China
| | - Yuxin Su
- Translational Medicine Research Center, Beijing Tsinghua Chang Gung Hospital, Beijing, 102218, China
- Department of Stem Cell and Regenerative Medicine, Beijing Institute of Health Service and Transfusion Medicine, Beijing, 100850, China
| | - Zuolong Tan
- Department of Stem Cell and Regenerative Medicine, Beijing Institute of Health Service and Transfusion Medicine, Beijing, 100850, China
| | - Mingyang Chang
- Department of Stem Cell and Regenerative Medicine, Beijing Institute of Health Service and Transfusion Medicine, Beijing, 100850, China
| | - Jinmei Diao
- Translational Medicine Research Center, Beijing Tsinghua Chang Gung Hospital, Beijing, 102218, China
| | - Yi Zhao
- Department of Dermatology, Beijing Tsinghua Chang Gung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, 102218, China
| | - Yunfang Wang
- Translational Medicine Research Center, Beijing Tsinghua Chang Gung Hospital, Beijing, 102218, China.
- Department of Stem Cell and Regenerative Medicine, Beijing Institute of Health Service and Transfusion Medicine, Beijing, 100850, China.
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12
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Sun L, Rollins D, Qi Y, Fredericks J, Mansell TJ, Jergens A, Phillips GJ, Wannemuehler M, Wang Q. TNFα regulates intestinal organoids from mice with both defined and conventional microbiota. Int J Biol Macromol 2020; 164:548-556. [PMID: 32693143 PMCID: PMC7657954 DOI: 10.1016/j.ijbiomac.2020.07.176] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 07/07/2020] [Accepted: 07/14/2020] [Indexed: 02/07/2023]
Abstract
Cytokines are key factors affecting the fate of intestinal stem cells (ISCs) and effective reagents to manipulate ISCs for research purpose. Tumor necrosis factor alpha (TNFα) is a cytokine produced primarily by monocytes and macrophages. It can induce apoptotic cell death and inflammation, and to inhibit tumorigenesis and viral replication. Additionally, TNFα has been shown to play a critical role in the pathogenesis of inflammatory bowel disease (IBD). It is therefore important to identify the mechanism by which individual cytokines affect particular cell types. For this purpose, we used both conventional (CONV) and altered Schaedler flora (ASF) C3H/HeN mice to elucidate the effect of different microbial populations (complex versus defined) on growth of miniguts derived from two different intestinal environments. Furthermore, we studied the effects of different concentrations of TNFα extracted from the lymph and spleen on the growth and viability of ISCs recovered from mice bearing the ASF or CONV microbiota. The effect of TNFα on miniguts growth depends not only on the source and concentration, but also on the intestinal microenvironment from which the ISCs were derived. The findings suggest that TNFα influences the proliferation of miniguts derived from ISCs and, therefore, modulates mucosal homeostasis of the host.
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Affiliation(s)
- Liping Sun
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States; School of Environmental & Resource Sciences, Zhejiang A&F University, Lin'an, Zhejiang 311300, China
| | - Derrick Rollins
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States; Department of Statistics, Iowa State University, Ames, IA, United States
| | - Yijun Qi
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States
| | - Jorrell Fredericks
- Department of Veterinary Microbiology and Preventative Medicine, Iowa State University, Ames, IA, United States
| | - Thomas J Mansell
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States
| | - Albert Jergens
- Department of Veterinary Clinical Sciences, Iowa State University, Ames, IA, United States
| | - Gregory J Phillips
- Department of Veterinary Microbiology and Preventative Medicine, Iowa State University, Ames, IA, United States
| | - Michael Wannemuehler
- Department of Veterinary Microbiology and Preventative Medicine, Iowa State University, Ames, IA, United States
| | - Qun Wang
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States.
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13
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Barron MR, Cieza RJ, Hill DR, Huang S, Yadagiri VK, Spence JR, Young VB. The Lumen of Human Intestinal Organoids Poses Greater Stress to Bacteria Compared to the Germ-Free Mouse Intestine: Escherichia coli Deficient in RpoS as a Colonization Probe. mSphere 2020; 5:e00777-20. [PMID: 33177212 PMCID: PMC7657587 DOI: 10.1128/msphere.00777-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/23/2020] [Indexed: 02/07/2023] Open
Abstract
Pluripotent stem-cell-derived human intestinal organoids (HIOs) are three-dimensional, multicellular structures that model a naive intestinal epithelium in an in vitro system. Several published reports have investigated the use of HIOs to study host-microbe interactions. We recently demonstrated that microinjection of the nonpathogenic Escherichia coli strain ECOR2 into HIOs induced morphological and functional maturation of the HIO epithelium, including increased secretion of mucins and cationic antimicrobial peptides. In the current work, we use ECOR2 as a biological probe to further characterize the environment present in the HIO lumen. We generated an isogenic mutant in the general stress response sigma factor RpoS and employed this mutant to compare challenges faced by a bacterium during colonization of the HIO lumen relative to the germ-free mouse intestine. We demonstrate that the loss of RpoS significantly decreases the ability of ECOR2 to colonize HIOs, although it does not prevent colonization of germ-free mice. These results indicate that the HIO lumen is a more restrictive environment to E. coli than the germ-free mouse intestine, thus increasing our understanding of the HIO model system as it pertains to studying the establishment of intestinal host-microbe symbioses.IMPORTANCE Technological advancements have driven and will continue to drive the adoption of organotypic systems for investigating host-microbe interactions within the human intestinal ecosystem. Using E. coli deficient in the RpoS-mediated general stress response, we demonstrate that the type or severity of microbial stressors within the HIO lumen is more restrictive than those of the in vivo environment of the germ-free mouse gut. This study provides important insight into the nature of the HIO microenvironment from a microbiological standpoint.
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Affiliation(s)
- Madeline R Barron
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Roberto J Cieza
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - David R Hill
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Sha Huang
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Veda K Yadagiri
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Jason R Spence
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Vincent B Young
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Medical School, Ann Arbor, Michigan, USA
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14
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Ranganathan S, Smith EM, Foulke-Abel JD, Barry EM. Research in a time of enteroids and organoids: how the human gut model has transformed the study of enteric bacterial pathogens. Gut Microbes 2020; 12:1795492. [PMID: 32795243 PMCID: PMC7524385 DOI: 10.1080/19490976.2020.1795389] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/29/2020] [Accepted: 07/01/2020] [Indexed: 02/03/2023] Open
Abstract
Enteric bacterial pathogens cause significant morbidity and mortality globally. Studies in tissue culture and animal models shaped our initial understanding of these host-pathogen interactions. However, intrinsic shortcomings in these models limit their application, especially in translational applications like drug screening and vaccine development. Human intestinal enteroid and organoid models overcome some limitations of existing models and advance the study of enteric pathogens. In this review, we detail the use of human enteroids and organoids to investigate the pathogenesis of invasive bacteria Shigella, Listeria, and Salmonella, and noninvasive bacteria pathogenic Escherichia coli, Clostridium difficile, and Vibrio cholerae. We highlight how these studies confirm previously identified mechanisms and, importantly, reveal novel ones. We also discuss the challenges for model advancement, including platform engineering to integrate environmental conditions, innate immune cells and the resident microbiome, and the potential for pre-clinical testing of recently developed antimicrobial drugs and vaccines.
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Affiliation(s)
- Sridevi Ranganathan
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Emily M. Smith
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jennifer D. Foulke-Abel
- Department of Medicine, Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Eileen M. Barry
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
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15
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Engevik MA, Danhof HA, Shrestha R, Chang-Graham AL, Hyser JM, Haag AM, Mohammad MA, Britton RA, Versalovic J, Sorg JA, Spinler JK. Reuterin disrupts Clostridioides difficile metabolism and pathogenicity through reactive oxygen species generation. Gut Microbes 2020; 12:1788898. [PMID: 32804011 PMCID: PMC7524292 DOI: 10.1080/19490976.2020.1795388] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/16/2020] [Accepted: 07/06/2020] [Indexed: 02/03/2023] Open
Abstract
Antibiotic resistance is one of the world's greatest public health challenges and adjunct probiotic therapies are strategies that could lessen this burden. Clostridioides difficile infection (CDI) is a prime example where adjunct probiotic therapies could decrease disease incidence through prevention. Human-derived Lactobacillus reuteri is a probiotic that produces the antimicrobial compound reuterin known to prevent C. difficile colonization of antibiotic-treated fecal microbial communities. However, the mechanism of inhibition is unclear. We show that reuterin inhibits C. difficile outgrowth from spores and vegetative cell growth, however, no effect on C. difficile germination or sporulation was observed. Consistent with published studies, we found that exposure to reuterin stimulated reactive oxygen species (ROS) in C. difficile, resulting in a concentration-dependent reduction in cell viability that was rescued by the antioxidant glutathione. Sublethal concentrations of reuterin enhanced the susceptibility of vegetative C. difficile to vancomycin and metronidazole treatment and reduced toxin synthesis by C. difficile. We also demonstrate that reuterin is protective against C. difficile toxin-mediated cellular damage in the human intestinal enteroid model. Overall, our results indicate that ROS are essential mediators of reuterin activity and show that reuterin production by L. reuteri is compatible as a therapeutic in a clinically relevant model.
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Affiliation(s)
- Melinda A. Engevik
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
| | - Heather A. Danhof
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Ritu Shrestha
- Department of Biology, Texas A&M University, College Station, TX, USA
| | | | - Joseph M. Hyser
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Anthony M. Haag
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Microbiome Center, Department of Pathology, Texas Children’s Hospital, Houston, TX, USA
| | - Mahmoud A. Mohammad
- Department of Pediatrics, Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA
| | - Robert A. Britton
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - James Versalovic
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Microbiome Center, Department of Pathology, Texas Children’s Hospital, Houston, TX, USA
| | - Joseph A. Sorg
- Department of Biology, Texas A&M University, College Station, TX, USA
| | - Jennifer K. Spinler
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Microbiome Center, Department of Pathology, Texas Children’s Hospital, Houston, TX, USA
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16
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Rubert J, Schweiger PJ, Mattivi F, Tuohy K, Jensen KB, Lunardi A. Intestinal Organoids: A Tool for Modelling Diet-Microbiome-Host Interactions. Trends Endocrinol Metab 2020; 31:848-858. [PMID: 33086077 DOI: 10.1016/j.tem.2020.02.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 02/04/2020] [Accepted: 02/06/2020] [Indexed: 12/12/2022]
Abstract
Dietary patterns, microbiome dysbiosis, and gut microbial metabolites (GMMs) have a pivotal role in the homeostasis of intestinal epithelial cells and in disease progression, such as that of colorectal cancer (CRC). Although GMMs and microorganisms have crucial roles in many biological activities, models for deciphering diet-microbiome-host relationships are largely limited to animal models. Thus, intestinal organoids (IOs) have provided unprecedented opportunities for the generation of in vitro platforms with the sufficient level of complexity to model physiological and pathological diet-microbiome-host conditions. Overall, IO responses to GMM metabolites and microorganisms can provide new insights into the mechanisms by which those agents may prevent or trigger diseases, significantly extending our knowledge of diet-microbiome-host interactions.
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Affiliation(s)
- Josep Rubert
- CIBIO - Department of Cellular, Computational, and Integrative Biology, University of Trento, Via Sommarive 9, Trento, Italy.
| | - Pawel J Schweiger
- BRIC - Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen N, DK-2200, Denmark; Novo Nordisk Foundation Center for Stem Cell Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Fulvio Mattivi
- CIBIO - Department of Cellular, Computational, and Integrative Biology, University of Trento, Via Sommarive 9, Trento, Italy
| | - Kieran Tuohy
- Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach (FEM), Via E. Mach 1, San Michele all'Adige, Italy
| | - Kim B Jensen
- BRIC - Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen N, DK-2200, Denmark; Novo Nordisk Foundation Center for Stem Cell Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Andrea Lunardi
- CIBIO - Department of Cellular, Computational, and Integrative Biology, University of Trento, Via Sommarive 9, Trento, Italy
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17
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Dougherty MW, Kudin O, Mühlbauer M, Neu J, Gharaibeh RZ, Jobin C. Gut microbiota maturation during early human life induces enterocyte proliferation via microbial metabolites. BMC Microbiol 2020; 20:205. [PMID: 32652929 PMCID: PMC7353703 DOI: 10.1186/s12866-020-01892-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 07/02/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The intestinal tract undergoes a period of cellular maturation during early life, primarily characterized by the organization of epithelial cells into specialized crypt and villus structures. These processes are in part mediated by the acquisition of microbes. Infants delivered at term typically harbor a stable, low diversity microbiota characterized by an overrepresentation of various Bacilli spp., while pre-term infants are colonized by an assortment of bacteria during the first several weeks after delivery. However, the functional effects of these changes on intestinal epithelium homeostasis and maturation remain unclear. To study these effects, human neonate feces were obtained from term and pre-term infants. Fecal 16S rDNA sequencing and global untargeted LC-MS were performed to characterize microbial composition and metabolites from each population. Murine enteral organoids (enteroids) were cultured with 0.22 μm filtered stool supernatant pooled from term or pre-term infants. RESULTS Term and pre-term microbial communities differed significantly from each other by principle components analysis (PCoA, PERMANOVA p < 0.001), with the pre-term microbiome characterized by increased OTU diversity (Wilcox test p < 0.01). Term communities were less diverse and dominated by Bacilli (81.54%). Pre-term stools had an increased abundance of vitamins, amino acid derivatives and unconjugated bile acids. Pathway analysis revealed a significant increase in multiple metabolic pathways in pre-term samples mapped to E. coli using the KEGG database related to the fermentation of various amino acids and vitamin biosynthesis. Enteroids cultured with supernatant from pre-term stools proliferated at a higher rate than those cultured with supernatant from term stools (cell viability: 207% vs. 147.7%, p < 0.01), grew larger (area: 81,189μm2 vs. 41,777μm2, p < 0.001), and bud at a higher rate (6.5 vs. 4, p < 0.01). Additionally, genes involved in stem cell proliferation were upregulated in pre-term stool treated enteroid cultures (Lgr5, Ephb2, Ascl2 Sox9) but not term stool treated enteroids. CONCLUSIONS Our findings indicate that microbial metabolites from the more diverse gut microbiome associated with pre-term infants facilitate stem cell proliferation. Therefore, perturbations of the pre-term microbiota may impair intestinal homeostasis.
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Affiliation(s)
- Michael W Dougherty
- Department of Medicine, Division of Gastroenterology, University of Florida, CGRC, 2033 Mowry Rd, Florida, 32610, USA
| | - Oleksandr Kudin
- Department of Pediatrics, University of Florida, Gainesville, Florida, USA
| | - Marcus Mühlbauer
- Department of Medicine, Division of Gastroenterology, University of Florida, CGRC, 2033 Mowry Rd, Florida, 32610, USA
| | - Josef Neu
- Department of Pediatrics, University of Florida, Gainesville, Florida, USA
| | - Raad Z Gharaibeh
- Department of Medicine, Division of Gastroenterology, University of Florida, CGRC, 2033 Mowry Rd, Florida, 32610, USA
| | - Christian Jobin
- Department of Medicine, Division of Gastroenterology, University of Florida, CGRC, 2033 Mowry Rd, Florida, 32610, USA.
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA.
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18
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Abstract
Escherichia coli strain Nissle has been used as a probiotic and therapeutic agent for over a century. Reports suggest that Nissle protects mice from enterohemorrhagic E. coli (EHEC) O157:H7 strains; however, mice are not very susceptible to O157:H7 and are not accurate models for O157:H7 infection in humans. Also, Nissle is closely related to uropathogenic E. coli (UPEC) strain CFT073, suggesting that Nissle could have pathogenic potential. To assess the safety of and protection conferred by Nissle, we modeled infection in stem cell-derived human intestinal organoids (HIOs). HIOs replicate the structure and function of human intestinal tissue. HIOs have a lumen enclosed by a single cell layer of differentiated epithelium, which is surrounded by a diffuse mesenchymal layer. An epithelial barrier which excludes the luminal contents from the surrounding cell layers and medium develops. Nissle appeared to be nonpathogenic; 103 CFU were microinjected into the lumen, and after 3 days, 107 CFU were recovered and the epithelial barrier remained intact. In contrast, microinjected EHEC and UPEC bacteria destroyed the epithelial barrier. To assess the protection conferred by Nissle, HIOs microinjected with Nissle were challenged after 18 to 24 h with EHEC or UPEC. Preincubation with Nissle prevented the loss of the epithelial barrier function, the loss of E-cadherin expression, the increased production of reactive oxygen species, and apoptosis. Nissle did not replicate in the HIO coculture, while the pathogenic strains did replicate, suggesting that Nissle conferred protection via activation of host defenses and not by eliminating competing strains. Nissle was shown to be susceptible to some Shiga toxin phage, and Nissle lysogens could produce Shiga toxin.IMPORTANCE Probiotic, or beneficial, bacteria, such as E. coli Nissle, hold promise for the treatment of human disease. More study is needed to fully realize the potential of probiotics. Safety and efficacy studies are critically important; however, mice are poor models for many human intestinal diseases. We used stem cell-derived human intestinal organoid tissues to evaluate the safety of Nissle and its ability to protect from pathogenic E. coli bacteria. Nissle was found to be safe. Human intestinal tissues were not harmed by the Nissle bacteria introduced into the digestive tract. In contrast, pathogenic E. coli bacteria destroyed the intestinal tissues, and importantly, Nissle conferred protection from the pathogenic E. coli bacteria. Nissle did not kill the pathogenic E. coli bacteria, and protection likely occurred via the activation of human defenses. Human intestinal tissues provide a powerful way to study complex host-microbe interactions.
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Affiliation(s)
- Suman Pradhan
- Department of Molecular Genetics, University of Cincinnati, Cincinnati, Ohio, USA
| | - Alison Ann Weiss
- Department of Molecular Genetics, University of Cincinnati, Cincinnati, Ohio, USA
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19
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Jiao Y, Zhang YG, Lin Z, Lu R, Xia Y, Meng C, Pan Z, Xu X, Jiao X, Sun J. Salmonella Enteritidis Effector AvrA Suppresses Autophagy by Reducing Beclin-1 Protein. Front Immunol 2020; 11:686. [PMID: 32362899 PMCID: PMC7181453 DOI: 10.3389/fimmu.2020.00686] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 03/26/2020] [Indexed: 12/20/2022] Open
Abstract
Autophagy is a cellular process to clear pathogens. Salmonella enterica serovar Enteritidis (S.E) has emerged as one of the most important food-borne pathogens. However, major studies still focus on Salmonella enterica serovar Typhimurium. Here, we reported that AvrA, a S. Enteritidis effector, inhibited autophagy to promote bacterial survival in the host. We found that AvrA regulates the conversion of LC3 I into LC3 II and the enrichment of lysosomes. Beclin-1, a key molecular regulator of autophagy, was decreased after AvrA expressed strain colonization. In S.E-AvrA--infected cells, we found the increases of protein levels of p-JNK and p-c-Jun and the transcription level of AP-1. AvrA-reduction of Beclin-1 protein expression is through the JNK pathway. The JNK inhibitor abolished the AvrA-reduced Beclin-1 protein expression. Moreover, we identified that the AvrA mutation C186A abolished its regulation of Beclin-1 expression. In addition AvrA protein was found interacted with Beclin-1. In organoids and infected mice, we explored the physiologically related effects and mechanism of AvrA in reducing Beclin-1 through the JNK pathway, thus attenuating autophagic responses. This finding not only indicates an important role of S. Enteritidis effector in reducing host protein as a strategy to suppress autophagy, but also suggests manipulating autophagy as a new strategy to treat infectious diseases.
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Affiliation(s)
- Yang Jiao
- Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Yong-guo Zhang
- Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Zhijie Lin
- Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Rong Lu
- Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Yinglin Xia
- Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Chuang Meng
- Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Zhimin Pan
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis, Yangzhou University, Yangzhou, China
| | - Xiulong Xu
- Department of Anatomy and Cell Biology, Rush University, Chicago, IL, United States
| | - Xinan Jiao
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis, Yangzhou University, Yangzhou, China
| | - Jun Sun
- Division of Gastroenterology and Hepatology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
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20
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Pleguezuelos-Manzano C, Puschhof J, Rosendahl Huber A, van Hoeck A, Wood HM, Nomburg J, Gurjao C, Manders F, Dalmasso G, Stege PB, Paganelli FL, Geurts MH, Beumer J, Mizutani T, Miao Y, van der Linden R, van der Elst S, Garcia KC, Top J, Willems RJL, Giannakis M, Bonnet R, Quirke P, Meyerson M, Cuppen E, van Boxtel R, Clevers H. Mutational signature in colorectal cancer caused by genotoxic pks + E. coli. Nature 2020; 580:269-273. [PMID: 32106218 PMCID: PMC8142898 DOI: 10.1038/s41586-020-2080-8] [Citation(s) in RCA: 522] [Impact Index Per Article: 130.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 02/17/2020] [Indexed: 02/06/2023]
Abstract
Various species of the intestinal microbiota have been associated with the development of colorectal cancer1,2, but it has not been demonstrated that bacteria have a direct role in the occurrence of oncogenic mutations. Escherichia coli can carry the pathogenicity island pks, which encodes a set of enzymes that synthesize colibactin3. This compound is believed to alkylate DNA on adenine residues4,5 and induces double-strand breaks in cultured cells3. Here we expose human intestinal organoids to genotoxic pks+ E. coli by repeated luminal injection over five months. Whole-genome sequencing of clonal organoids before and after this exposure revealed a distinct mutational signature that was absent from organoids injected with isogenic pks-mutant bacteria. The same mutational signature was detected in a subset of 5,876 human cancer genomes from two independent cohorts, predominantly in colorectal cancer. Our study describes a distinct mutational signature in colorectal cancer and implies that the underlying mutational process results directly from past exposure to bacteria carrying the colibactin-producing pks pathogenicity island.
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Affiliation(s)
- Cayetano Pleguezuelos-Manzano
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, Utrecht, The Netherlands
- Oncode Institute, Utrecht, The Netherlands
| | - Jens Puschhof
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, Utrecht, The Netherlands
- Oncode Institute, Utrecht, The Netherlands
| | - Axel Rosendahl Huber
- Oncode Institute, Utrecht, The Netherlands
- The Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | - Arne van Hoeck
- Oncode Institute, Utrecht, The Netherlands
- Center for Molecular Medicine, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Henry M Wood
- Pathology and Data Analytics, Leeds Institute of Medical Research at St James's, University of Leeds, Leeds, UK
| | - Jason Nomburg
- Graduate Program in Virology, Division of Medical Sciences, Harvard Medical School, Boston, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Carino Gurjao
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Freek Manders
- Oncode Institute, Utrecht, The Netherlands
- The Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | - Guillaume Dalmasso
- University Clermont Auvergne, Inserm U1071, INRA USC2018, M2iSH, Clermont-Ferrand, France
| | - Paul B Stege
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Fernanda L Paganelli
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Maarten H Geurts
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, Utrecht, The Netherlands
- Oncode Institute, Utrecht, The Netherlands
| | - Joep Beumer
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, Utrecht, The Netherlands
| | - Tomohiro Mizutani
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, Utrecht, The Netherlands
- Oncode Institute, Utrecht, The Netherlands
| | - Yi Miao
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Reinier van der Linden
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, Utrecht, The Netherlands
| | - Stefan van der Elst
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, Utrecht, The Netherlands
| | - K Christopher Garcia
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Janetta Top
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rob J L Willems
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marios Giannakis
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Richard Bonnet
- University Clermont Auvergne, Inserm U1071, INRA USC2018, M2iSH, Clermont-Ferrand, France
- Department of Bacteriology, University Hospital of Clermont-Ferrand, Clermont-Ferrand, France
| | - Phil Quirke
- Pathology and Data Analytics, Leeds Institute of Medical Research at St James's, University of Leeds, Leeds, UK
| | - Matthew Meyerson
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Edwin Cuppen
- Oncode Institute, Utrecht, The Netherlands
- Center for Molecular Medicine, University Medical Centre Utrecht, Utrecht, The Netherlands
- Hartwig Medical Foundation, Amsterdam, The Netherlands
- CPCT Consortium, Rotterdam, The Netherlands
| | - Ruben van Boxtel
- Oncode Institute, Utrecht, The Netherlands.
- The Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands.
| | - Hans Clevers
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, Utrecht, The Netherlands.
- Oncode Institute, Utrecht, The Netherlands.
- The Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands.
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21
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Min S, Kim S, Cho SW. Gastrointestinal tract modeling using organoids engineered with cellular and microbiota niches. Exp Mol Med 2020; 52:227-237. [PMID: 32103122 PMCID: PMC7062772 DOI: 10.1038/s12276-020-0386-0] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/21/2019] [Accepted: 12/27/2019] [Indexed: 02/08/2023] Open
Abstract
The recent emergence of organoid technology has attracted great attention in gastroenterology because the gastrointestinal (GI) tract can be recapitulated in vitro using organoids, enabling disease modeling and mechanistic studies. However, to more precisely emulate the GI microenvironment in vivo, several neighboring cell types and types of microbiota need to be integrated into GI organoids. This article reviews the recent progress made in elucidating the crosstalk between GI organoids and components of their microenvironment. We outline the effects of stromal cells (such as fibroblasts, neural cells, immune cells, and vascular cells) on the gastric and intestinal epithelia of organoids. Because of the important roles that microbiota play in the physiology and function of the GI tract, we also highlight interactions between organoids and commensal, symbiotic, and pathogenic microorganisms and viruses. GI organoid models that contain niche components will provide new insight into gastroenterological pathophysiology and disease mechanisms.
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Affiliation(s)
- Sungjin Min
- Department of Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Suran Kim
- Department of Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Seung-Woo Cho
- Department of Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea.
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22
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Zhang YG, Zhu X, Lu R, Messer JS, Xia Y, Chang EB, Sun J. Intestinal epithelial HMGB1 inhibits bacterial infection via STAT3 regulation of autophagy. Autophagy 2019; 15:1935-1953. [PMID: 30894054 PMCID: PMC6844505 DOI: 10.1080/15548627.2019.1596485] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 02/20/2019] [Accepted: 03/01/2019] [Indexed: 12/30/2022] Open
Abstract
Extracellular HMGB1 (high mobility group box 1) is considered as a damage-associated molecular pattern protein. However, little is known about its intracellular role. We studied the mechanism whereby intestinal epithelial HMGB1 contributes to host defense, using cell culture, colonoids, conditional intestinal epithelial HMGB1-knockout mice with Salmonella-colitis, il10-/- mice, and human samples. We report that intestinal HMGB1 is an important contributor to host protection from inflammation and infection. We identified a physical interaction between HMGB1 and STAT3. Lacking intestinal epithelial HMGB1 led to redistribution of STAT3 and activation of STAT3 post bacterial infection. Indeed, Salmonella-infected HMGB1-deficient cells exhibited less macroautophagy/autophagy due to decreased expression of autophagy proteins and transcriptional repression by activated STAT3. Then, increased p-STAT3 and extranuclear STAT3 reduced autophagic responses and increased inflammation. STAT3 inhibition restored autophagic responses and reduced bacterial invasion in vitro and in vivo. Moreover, low level of HMGB1 was correlated with reduced nuclear STAT3 and enhanced p-STAT3 in inflamed intestine of il10-/- mice and inflammatory bowel disease (IBD) patients. We revealed that colonic epithelial HMGB1 was directly involved in the suppression of STAT3 activation and the protection of intestine from bacterial infection and injury. Abbreviations: ATG16L1: autophagy-related 16-like 1 (S. cerevisiae); DAMP: damage-associated molecular pattern; HBSS: Hanks balanced salt solution; HMGB1: high mobility group box 1; IBD: inflammatory bowel disease; IL1B/Il-1β: interleukin 1 beta; IL10: interleukin 10; IL17/IL-17: interleukin 17; MEFs: mouse embryonic fibroblasts; STAT3: signal transducer and activator of transcription 3; TLR: toll-like receptor; TNF/TNF-α: tumor necrosis factor.
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Affiliation(s)
- Yong-Guo Zhang
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Xiaorong Zhu
- Department of Medicine, Knapp Center for Biomedical Discovery, University of Chicago, Chicago, IL, USA
| | - Rong Lu
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Jeannette S. Messer
- Department of Medicine, Knapp Center for Biomedical Discovery, University of Chicago, Chicago, IL, USA
| | - Yinglin Xia
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Eugene B. Chang
- Department of Medicine, Knapp Center for Biomedical Discovery, University of Chicago, Chicago, IL, USA
| | - Jun Sun
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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23
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Fitzgerald SF, Beckett AE, Palarea-Albaladejo J, McAteer S, Shaaban S, Morgan J, Ahmad NI, Young R, Mabbott NA, Morrison L, Bono JL, Gally DL, McNeilly TN. Shiga toxin sub-type 2a increases the efficiency of Escherichia coli O157 transmission between animals and restricts epithelial regeneration in bovine enteroids. PLoS Pathog 2019; 15:e1008003. [PMID: 31581229 PMCID: PMC6776261 DOI: 10.1371/journal.ppat.1008003] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/25/2019] [Indexed: 02/06/2023] Open
Abstract
Specific Escherichia coli isolates lysogenised with prophages that express Shiga toxin (Stx) can be a threat to human health, with cattle being an important natural reservoir. In many countries the most severe pathology is associated with enterohaemorrhagic E. coli (EHEC) serogroups that express Stx subtype 2a. In the United Kingdom, phage type (PT) 21/28 O157 strains have emerged as the predominant cause of life-threatening EHEC infections and this phage type commonly encodes both Stx2a and Stx2c toxin types. PT21/28 is also epidemiologically linked to super-shedding (>103 cfu/g of faeces) which is significant for inter-animal transmission and human infection as demonstrated using modelling studies. We demonstrate that Stx2a is the main toxin produced by stx2a+/stx2c+ PT21/28 strains induced with mitomycin C and this is associated with more rapid induction of gene expression from the Stx2a-encoding prophage compared to that from the Stx2c-encoding prophage. Bacterial supernatants containing either Stx2a and/or Stx2c were demonstrated to restrict growth of bovine gastrointestinal organoids with no restriction when toxin production was not induced or prevented by mutation. Isogenic strains that differed in their capacity to produce Stx2a were selected for experimental oral colonisation of calves to assess the significance of Stx2a for both super-shedding and transmission between animals. Restoration of Stx2a expression in a PT21/28 background significantly increased animal-to-animal transmission and the number of sentinel animals that became super-shedders. We propose that while both Stx2a and Stx2c can restrict regeneration of the epithelium, it is the relatively rapid and higher levels of Stx2a induction, compared to Stx2c, that have contributed to the successful emergence of Stx2a+ E. coli isolates in cattle in the last 40 years. We propose a model in which Stx2a enhances E. coli O157 colonisation of in-contact animals by restricting regeneration and turnover of the colonised gastrointestinal epithelium. Enterohaemorrhagic E. coli (EHEC) O157 strains are found in cattle where they are asymptomatic, while human exposure can lead to severe symptoms including bloody diarrhoea and kidney damage due to the activity of Shiga toxin (Stx). The most serious symptoms in humans are associated with isolates that encode Stx subtype 2a. The advantage of these toxins in the animal reservoir is still not clear, however there is experimental evidence implicating Stx with increased bacterial adherence, immune modulation and suppression of predatory protozoa. In this study, the hypothesis that Stx2a is important for super-shedding and calf-to-calf transmission was tested by comparing excretion and transmission dynamics of E. coli O157 strains with and without Stx2a. While Stx2a did not alter excretion levels when calfs were orally challenge, it enabled colonisation of more in contact ‘sentinel’ animals in our transmission model. We show that Stx2a is generally induced more rapidly than Stx2c, resulting in increased levels of Stx2a expression. Both Stx2a and Stx2c were able to restrict cellular proliferation of epithelial cells in cultured bovine enteroids. Taken together, we propose that rapid production of Stx2a and its role in establishing E. coli O157 colonisation in the bovine gastrointestinal tract facilitate effective transmission and have led to its expansion in the cattle E. coli O157 population.
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Affiliation(s)
- Stephen F. Fitzgerald
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
- Moredun Research Institute, Penicuik, United Kingdom
| | - Amy E. Beckett
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
- Moredun Research Institute, Penicuik, United Kingdom
| | | | - Sean McAteer
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
| | - Sharif Shaaban
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
| | - Jason Morgan
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
- Moredun Research Institute, Penicuik, United Kingdom
| | | | - Rachel Young
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
| | - Neil A. Mabbott
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
| | - Liam Morrison
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
| | - James L. Bono
- United States Department of Agriculture, Agricultural Research Service, Nebraska, United States of America
| | - David L. Gally
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
- * E-mail: (DLG); (TNM)
| | - Tom N. McNeilly
- Moredun Research Institute, Penicuik, United Kingdom
- * E-mail: (DLG); (TNM)
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24
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Liu R, Moriggl R, Zhang D, Li H, Karns R, Ruan HB, Niu H, Mayhew C, Watson C, Bangar H, Cha SW, Haslam D, Zhang T, Gilbert S, Li N, Helmrath M, Wells J, Denson L, Han X. Constitutive STAT5 activation regulates Paneth and Paneth-like cells to control Clostridium difficile colitis. Life Sci Alliance 2019; 2:e201900296. [PMID: 30948494 PMCID: PMC6451325 DOI: 10.26508/lsa.201900296] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 03/27/2019] [Accepted: 03/27/2019] [Indexed: 12/17/2022] Open
Abstract
Clostridium difficile impairs Paneth cells, driving intestinal inflammation that exaggerates colitis. Besides secreting bactericidal products to restrain C. difficile, Paneth cells act as guardians that constitute a niche for intestinal epithelial stem cell (IESC) regeneration. However, how IESCs are sustained to specify Paneth-like cells as their niche remains unclear. Cytokine-JAK-STATs are required for IESC regeneration. We investigated how constitutive STAT5 activation (Ca-pYSTAT5) restricts IESC differentiation towards niche cells to restrain C. difficile infection. We generated inducible transgenic mice and organoids to determine the effects of Ca-pYSTAT5-induced IESC lineages on C. difficile colitis. We found that STAT5 absence reduced Paneth cells and predisposed mice to C. difficile ileocolitis. In contrast, Ca-pYSTAT5 enhanced Paneth cell lineage tracing and restricted Lgr5 IESC differentiation towards pYSTAT5+Lgr5-CD24+Lyso+ or cKit+ niche cells, which imprinted Lgr5hiKi67+ IESCs. Mechanistically, pYSTAT5 activated Wnt/β-catenin signaling to determine Paneth cell fate. In conclusion, Ca-pYSTAT5 gradients control niche differentiation. Lack of pYSTAT5 reduces the niche cells to sustain IESC regeneration and induces C. difficile ileocolitis. STAT5 may be a transcription factor that regulates Paneth cells to maintain niche regeneration.
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Affiliation(s)
- Ruixue Liu
- Key Laboratory of Human Disease Comparative Medicine, the Ministry of Health, Institute of Laboratory Animal Sciences, Chinese Academy Institute of Medical Sciences and Peking Union Medical College, Beijing, P.R. China
| | - Richard Moriggl
- Ludwig Boltzmann Institute for Cancer Research, Vienna, Austria
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Vienna, Austria
- Medical University of Vienna, Vienna, Austria
| | - Dongsheng Zhang
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, OH, USA
| | - Haifeng Li
- Key Laboratory of Human Disease Comparative Medicine, the Ministry of Health, Institute of Laboratory Animal Sciences, Chinese Academy Institute of Medical Sciences and Peking Union Medical College, Beijing, P.R. China
| | - Rebekah Karns
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, OH, USA
| | - Hai-Bin Ruan
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MI, USA
| | - Haitao Niu
- Key Laboratory of Human Disease Comparative Medicine, the Ministry of Health, Institute of Laboratory Animal Sciences, Chinese Academy Institute of Medical Sciences and Peking Union Medical College, Beijing, P.R. China
| | | | - Carey Watson
- Division of Pediatric Surgery, CCHMC, Cincinnati, OH, USA
| | - Hansraj Bangar
- Division of Infectious Diseases, CCHMC, Cincinnati, OH, USA
| | - Sang-Wook Cha
- Division of Developmental Biology, CCHMC, Cincinnati, OH, USA
| | - David Haslam
- Division of Infectious Diseases, CCHMC, Cincinnati, OH, USA
| | - Tongli Zhang
- Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, OH, USA
| | - Shila Gilbert
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, OH, USA
| | - Na Li
- Key Laboratory of Human Disease Comparative Medicine, the Ministry of Health, Institute of Laboratory Animal Sciences, Chinese Academy Institute of Medical Sciences and Peking Union Medical College, Beijing, P.R. China
| | | | - James Wells
- Division of Developmental Biology, CCHMC, Cincinnati, OH, USA
- Division of Endocrinology, CCHMC, Cincinnati, OH, USA
- Center for Stem Cell and Organoid Medicine, CCHMC, Cincinnati, OH, USA
| | - Lee Denson
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, OH, USA
| | - Xiaonan Han
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, OH, USA
- Key Laboratory of Human Disease Comparative Medicine, the Ministry of Health, Institute of Laboratory Animal Sciences, Chinese Academy Institute of Medical Sciences and Peking Union Medical College, Beijing, P.R. China
- Department of Pediatrics, University of Cincinnati College of Medicine, OH, USA
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25
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Abstract
The intestinal epithelial cells function to gain nutrients, retain water and electrolytes, and form an efficient barrier against foreign microbes and antigens. Researchers employed cell culture lines derived from human or animal cancer cells as experimental models in vitro for understanding of intestinal infections. However, most in vitro models used to investigate interactions between bacteria and intestinal epithelial cells fail to recreate the differentiated tissue components and structure observed in the normal intestine. The in vitro analysis of host-bacteria interactions in the intestine has been hampered by a lack of suitable intestinal epithelium culture systems. Here, we present a new experimental model using an organoid culture system to study bacterial infection.
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Affiliation(s)
- Yong-Guo Zhang
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, 840 S Wood Street, Chicago, IL, 60612, USA
| | - Jun Sun
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, 840 S Wood Street, Room 704 CSB, Chicago, IL, 60612, USA.
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26
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Forbester JL, Hannan N, Vallier L, Dougan G. Derivation of Intestinal Organoids from Human Induced Pluripotent Stem Cells for Use as an Infection System. Methods Mol Biol 2019; 1576:157-169. [PMID: 27576565 DOI: 10.1007/7651_2016_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Intestinal human organoids (iHOs) provide an effective system for studying the intestinal epithelium and its interaction with various stimuli. By using combinations of different signaling factors, human induced pluripotent stem cells (hIPSCs) can be driven to differentiate down the intestinal lineage. Here, we describe the process for this differentiation, including the derivation of hindgut from hIPSCs, embedding hindgut into a pro-intestinal culture system and passaging the resulting iHOs. We then describe how to carry out microinjections to introduce bacteria to the apical side of the intestinal epithelial cells (IECs).
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Affiliation(s)
| | | | - Ludovic Vallier
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
- Wellcome Trust-Medical Research Council Stem Cell Institute, Anne McLaren Laboratory, Department of Surgery, University of Cambridge, Cambridge, UK
| | - Gordon Dougan
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
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27
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Abstract
The gut, particularly the colon, is the host of approximately 1000 bacterial species, the so-called gut microbiota. The relationship between the gut microbiota and the host is symbiotic and mutualistic, influencing many aspects of the biology of the host. This homeostatic balance can be disrupted by enteric pathogens, such as Shigella flexneri or Listeria monocytogenes, which are able to invade the epithelial layer and consequently subvert physiological functions. To study the host-microbe interactions in vitro, the crypt culture model, known as intestinal organoids, is a powerful tool. Intestinal organoids provide a model in which to examine the response of the epithelium, particularly the response of intestinal stem cells, to the presence of bacteria. Furthermore, the organoid model enables the study of pathogens during the early steps of enteric pathogen invasion.Here, we describe methods that we have established to study the cellular microbiology of symbiosis between the gut microbiota and host intestinal surface and secondly the disruption of host homeostasis due to an enteric pathogen.
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Affiliation(s)
- Giulia Nigro
- Molecular Microbial Pathogenesis Unit, Inserm U1202, Institut Pasteur, 28, rue du docteur Roux, Paris, 75015, France.
| | - Melissa Hanson
- Biology of Infection Unit, Inserm U1117, Institut Pasteur, 28, rue du docteur Roux, Paris, 75015, France
| | - Cindy Fevre
- Biology of Infection Unit, Inserm U1117, Institut Pasteur, 28, rue du docteur Roux, Paris, 75015, France
| | - Marc Lecuit
- Biology of Infection Unit, Inserm U1117, Institut Pasteur, 28, rue du docteur Roux, Paris, 75015, France
| | - Philippe J Sansonetti
- Molecular Microbial Pathogenesis Unit, Inserm U1202, Institut Pasteur, 28, rue du docteur Roux, Paris, 75015, France
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28
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Holokai L, Chakrabarti J, Broda T, Chang J, Hawkins JA, Sundaram N, Wroblewski LE, Peek RM, Wang J, Helmrath M, Wells JM, Zavros Y. Increased Programmed Death-Ligand 1 is an Early Epithelial Cell Response to Helicobacter pylori Infection. PLoS Pathog 2019; 15:e1007468. [PMID: 30703170 PMCID: PMC6380601 DOI: 10.1371/journal.ppat.1007468] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 02/19/2019] [Accepted: 11/13/2018] [Indexed: 12/24/2022] Open
Abstract
Helicobacter pylori (H. pylori) is the major risk factor for the development of gastric cancer. Our laboratory has reported that the Sonic Hedgehog (Shh) signaling pathway is an early response to infection that is fundamental to the initiation of H. pylori-induced gastritis. H. pylori also induces programmed death ligand 1 (PD-L1) expression on gastric epithelial cells, yet the mechanism is unknown. We hypothesize that H. pylori-induced PD-L1 expression within the gastric epithelium is mediated by the Shh signaling pathway during infection. To identify the role of Shh signaling as a mediator of H. pylori-induced PD-L1 expression, human gastric organoids generated from either induced pluripotent stem cells (HGOs) or tissue (huFGOs) were microinjected with bacteria and treated with Hedgehog/Gli inhibitor GANT61. Gastric epithelial monolayers generated from the huFGOs were also infected with H. pylori and treated with GANT61 to study the role of Hedgehog signaling as a mediator of induced PD-1 expression. A patient-derived organoid/autologous immune cell co-culture system infected with H. pylori and treated with PD-1 inhibitor (PD-1Inh) was developed to study the protective mechanism of PD-L1 in response to bacterial infection. H. pylori significantly increased PD-L1 expression in organoid cultures 48 hours post-infection when compared to uninfected controls. The mechanism was cytotoxic associated gene A (CagA) dependent. This response was blocked by pretreatment with GANT61. Anti-PD-L1 treatment of H. pylori infected huFGOs, co-cultured with autologous patient cytotoxic T lymphocytes and dendritic cells, induced organoid death. H. pylori-induced PD-L1 expression is mediated by the Shh signaling pathway within the gastric epithelium. Cells infected with H. pylori that express PD-L1 may be protected from the immune response, creating premalignant lesions progressing to gastric cancer.
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Affiliation(s)
- Loryn Holokai
- Department of Molecular Genetics, Biochemistry, and Microbiology, Cincinnati OH, United States of America
| | - Jayati Chakrabarti
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati OH, United States of America
| | - Taylor Broda
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
- Center for Stem Cell and Organoid Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
| | - Julie Chang
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati OH, United States of America
| | - Jennifer A. Hawkins
- Department of Pediatric Surgery, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
| | - Nambirajan Sundaram
- Department of Pediatric Surgery, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
| | - Lydia E. Wroblewski
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Richard M. Peek
- Division of Gastroenterology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Jiang Wang
- Department of Pathology and Lab Medicine, University of Cincinnati College of Medicine, Cincinnati OH, United States of America
| | - Michael Helmrath
- Department of Pediatric Surgery, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
| | - James M. Wells
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
- Center for Stem Cell and Organoid Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati OH, United States of America
| | - Yana Zavros
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati OH, United States of America
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29
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Higginson EE, Ramachandran G, Panda A, Shipley ST, Kriel EH, DeTolla LJ, Lipsky M, Perkins DJ, Salerno-Goncalves R, Sztein MB, Pasetti MF, Levine MM, Tennant SM. Improved Tolerability of a Salmonella enterica Serovar Typhimurium Live-Attenuated Vaccine Strain Achieved by Balancing Inflammatory Potential with Immunogenicity. Infect Immun 2018; 86:e00440-18. [PMID: 30249748 PMCID: PMC6246900 DOI: 10.1128/iai.00440-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 09/19/2018] [Indexed: 12/23/2022] Open
Abstract
A notable proportion of Salmonella-associated gastroenteritis in the United States is attributed to Salmonella enterica serovar Typhimurium. We have previously shown that live-attenuated S Typhimurium vaccine candidate CVD 1921 (I77 ΔguaBA ΔclpP) was safe and immunogenic in rhesus macaques but was shed for an undesirably long time postimmunization. In mice, occasional mortality postvaccination was also noted (approximately 1 in every 15 mice). Here we describe a further attenuated vaccine candidate strain harboring deletions in two additional genes, htrA and pipA We determined that S Typhimurium requires pipA to elicit fluid accumulation in a rabbit ileal loop model of gastroenteritis, as an S Typhimurium ΔpipA mutant induced significantly less fluid accumulation in rabbit loops than the wild-type strain. New vaccine strain CVD 1926 (I77 ΔguaBA ΔclpP ΔpipA ΔhtrA) was assessed for inflammatory potential in an organoid model of human intestinal mucosa, where it induced less inflammatory cytokine production than organoids exposed to the precursor vaccine, CVD 1921. To assess vaccine safety and efficacy, mice were given three doses of CVD 1926 (109 CFU/dose) by oral gavage, and at 1 or 3 months postimmunization, mice were challenged with 700 or 100 LD50 (50% lethal doses), respectively, of wild-type strain I77. CVD 1926 was well tolerated and exhibited 47% vaccine efficacy following challenge with a high inoculum and 60% efficacy after challenge with a low inoculum of virulent S Typhimurium. CVD 1926 is less reactogenic yet equally as immunogenic and protective as previous iterations in a mouse model.
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Affiliation(s)
- Ellen E Higginson
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Girish Ramachandran
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Aruna Panda
- Program of Comparative Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Steven T Shipley
- Program of Comparative Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Edwin H Kriel
- Program of Comparative Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Louis J DeTolla
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Program of Comparative Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Michael Lipsky
- Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Darren J Perkins
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Rosangela Salerno-Goncalves
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Marcelo B Sztein
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Marcela F Pasetti
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Myron M Levine
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Sharon M Tennant
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Westmeier D, Posselt G, Hahlbrock A, Bartfeld S, Vallet C, Abfalter C, Docter D, Knauer SK, Wessler S, Stauber RH. Nanoparticle binding attenuates the pathobiology of gastric cancer-associated Helicobacter pylori. Nanoscale 2018; 10:1453-1463. [PMID: 29303193 DOI: 10.1039/c7nr06573f] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Enteric bacteria may cause severe diseases, including gastric cancer-associated Helicobacter pylori. Their infection paths overlap with the oro-gastrointestinal uptake route for nanoparticles, increasingly occurring during environmental or consumer/medical exposure. By comprehensive independent analytical methods, such as live cell fluorescence, electron as well as atomic force microscopy and elemental analysis, we show that a wide array of nanoparticles (NPs) but not microparticles form complexes with H. pylori and enteric pathogens without the need for specific functionalization. The NP-assembly that occurred rapidly was not influenced by variations in physiological temperature, though affected by the NPs' physico-chemical characteristics. Improved binding was observed for small NPs with a negative surface charge, whereas binding could be reduced by surface 'stealth' modifications. Employing human gastric epithelial cells and 3D-organoid models of the stomach, we show that NP-coating did not inhibit H. pylori's cellular attachment. However, even the assembly of non-bactericidal silica NPs attenuated H. pylori infection by reducing CagA phosphorylation, cytoskeletal rearrangement, and IL-8 secretion. Here we demonstrate that NP binding to enteric bacteria may impact their pathobiology which could be further exploited to rationally modulate the (patho)biology of microbes by nanomaterials.
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Affiliation(s)
- Dana Westmeier
- Department of Nanobiomedicine/ENT, University Medical Center of Mainz, Langenbeckstrasse 1, 55101 Mainz, Germany.
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31
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Forbester JL, Goulding D, Vallier L, Hannan N, Hale C, Pickard D, Mukhopadhyay S, Dougan G. Interaction of Salmonella enterica Serovar Typhimurium with Intestinal Organoids Derived from Human Induced Pluripotent Stem Cells. Infect Immun 2015; 83:2926-34. [PMID: 25964470 PMCID: PMC4468523 DOI: 10.1128/iai.00161-15] [Citation(s) in RCA: 186] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 04/24/2015] [Indexed: 11/20/2022] Open
Abstract
The intestinal mucosa forms the first line of defense against infections mediated by enteric pathogens such as salmonellae. Here we exploited intestinal "organoids" (iHOs) generated from human induced pluripotent stem cells (hIPSCs) to explore the interaction of Salmonella enterica serovar Typhimurium with iHOs. Imaging and RNA sequencing were used to analyze these interactions, and clear changes in transcriptional signatures were detected, including altered patterns of cytokine expression after the exposure of iHOs to bacteria. S. Typhimurium microinjected into the lumen of iHOs was able to invade the epithelial barrier, with many bacteria residing within Salmonella-containing vacuoles. An S. Typhimurium invA mutant defective in the Salmonella pathogenicity island 1 invasion apparatus was less capable of invading the iHO epithelium. Hence, we provide evidence that hIPSC-derived organoids are a promising model of the intestinal epithelium for assessing interactions with enteric pathogens.
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Affiliation(s)
- Jessica L Forbester
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
| | - David Goulding
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
| | - Ludovic Vallier
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom Wellcome Trust-Medical Research Council Stem Cell Institute, Anne McLaren Laboratory, Department of Surgery, West Forvie Site, University of Cambridge, Cambridge, United Kingdom
| | - Nicholas Hannan
- Wellcome Trust-Medical Research Council Stem Cell Institute, Anne McLaren Laboratory, Department of Surgery, West Forvie Site, University of Cambridge, Cambridge, United Kingdom
| | - Christine Hale
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
| | - Derek Pickard
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
| | | | - Gordon Dougan
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
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32
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Höner zu Bentrup K, Ramamurthy R, Ott CM, Emami K, Nelman-Gonzalez M, Wilson JW, Richter EG, Goodwin TJ, Alexander JS, Pierson DL, Pellis N, Buchanan KL, Nickerson CA. Three-dimensional organotypic models of human colonic epithelium to study the early stages of enteric salmonellosis. Microbes Infect 2006; 8:1813-25. [PMID: 16730210 DOI: 10.1016/j.micinf.2006.02.020] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2005] [Revised: 02/11/2006] [Accepted: 02/16/2006] [Indexed: 11/28/2022]
Abstract
In vitro cell culture models used to study how Salmonella initiates disease at the intestinal epithelium would benefit from the recognition that organs and tissues function in a three-dimensional (3-D) environment and that this spatial context is necessary for development of cultures that more realistically resemble in vivo tissues/organs. Our aim was to establish and characterize biologically meaningful 3-D models of human colonic epithelium and apply them to study the early stages of enteric salmonellosis. The human colonic cell line HT-29 was cultured in 3-D and characterized by immunohistochemistry, histology, and scanning electron microscopy. Wild-type Salmonella typhimurium and an isogenic SPI-1 type three secretion system (TTSS) mutant derivative (invA) were used to compare the interactions with 3-D cells and monolayers in adherence/invasion, tissue pathology, and cytokine expression studies. The results showed that 3-D culture enhanced many characteristics normally associated with fully differentiated, functional intestinal epithelia in vivo, including better organization of junctional, extracellular matrix, and brush-border proteins, and highly localized mucin production. Wild-type Salmonella demonstrated increased adherence, but significantly lower invasion for 3-D cells. Interestingly, the SPI-I TTSS mutant showed wild-type ability to invade into the 3-D cells but did not cause significant structural changes to these cells. Moreover, 3-D cells produced less interleukin-8 before and after Salmonella infection. These results suggest that 3-D cultures of human colonic epithelium provide valuable alternative models to study human enteric salmonellosis with potential for novel insight into Salmonella pathogenesis.
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Affiliation(s)
- Kerstin Höner zu Bentrup
- Department of Microbiology and Immunology, Program in Molecular Pathogenesis and Immunity, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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33
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Smith YC, Grande KK, Rasmussen SB, O'Brien AD. Novel three-dimensional organoid model for evaluation of the interaction of uropathogenic Escherichia coli with terminally differentiated human urothelial cells. Infect Immun 2006; 74:750-7. [PMID: 16369034 PMCID: PMC1346604 DOI: 10.1128/iai.74.1.750-757.2006] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human bladder 5637 cells cultivated under microgravity conditions formed organoids that displayed characteristics of in vivo tissue-specific differentiation. Uropathogenic Escherichia coli (UPEC) strain CP9 colonized and penetrated the organoids and induced alpha-hemolysin-mediated exfoliation of uroepithelial cells. We propose these uro-organoids as models that simulate the interactions between UPEC and terminally differentiated human urothelium.
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Affiliation(s)
- Yarery C Smith
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Rm. B4052, 4301 Jones Bridge Rd., Bethesda, MD 20814-4799, USA
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Abstract
Internalized human rhinovirus 2 (HRV2) undergoes a rapid conformational change leading to recognition by the C-determinant-specific monoclonal antibody 2G2. In the presence of the ionophore monensin, the virus accumulates in the cells in its native conformation and infection is strongly inhibited. At 20 degrees but not at 34 degrees the inhibitory effect of monensin can be overcome by a short incubation of the infected cells at low pH as late as 2 hr after inoculation. Incubation of infected cells at 20 degrees prior to addition of monensin permits virus synthesis to occur, depending on the time of preincubation.
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Gollins SW, Porterfield JS. The uncoating and infectivity of the flavivirus West Nile on interaction with cells: effects of pH and ammonium chloride. J Gen Virol 1986; 67 ( Pt 9):1941-50. [PMID: 3746254 DOI: 10.1099/0022-1317-67-9-1941] [Citation(s) in RCA: 73] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Infectivity of the West Nile virus (WNV; Flaviviridae) was inactivated on exposure for brief periods (90 s) to pH 6.6 and below. This inactivation was not due to decreased interaction between cells and acid-treated virus. The RNA of [3H]uridine-labelled virus particles prebound to the cell surface before acidic pH treatment underwent rapid uncoating within 1 min at 37 degrees C at the same pH values that inactivated virus particles. The uncoating of [3H]uridine-labelled virus particles was also studied over longer time periods after synchronized internalization by P388D1 cells. At pH 7.6 uncoating occurred rapidly after a reproducible time lag of 1 min on warming to 37 degrees C and was essentially complete by 15 to 30 min after the start of internalization, leaving uncoated RNA in an infectious form. In contrast, at pH 6.2 viral uncoating occurred rapidly without any time lag and the uncoated RNA appeared to be far less infectious than that uncoated at pH 7.6. Ammonium chloride could almost totally inhibit both the infectivity and uncoating of virus particles on synchronized internalization into P388D1 cells, with a pH optimum of 8.0. These results suggest that the uncoating of virus particles is dependent on an acidic pH, although the location of uncoating (prelysosomal endosome or plasma membrane) decides whether the uncoated RNA will be infectious or not. Essentially the same results were obtained when infections were carried out in the presence of enhancing antibody.
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Yong EC, Chi EY, Chen WJ, Kuo CC. Degradation of Chlamydia trachomatis in human polymorphonuclear leukocytes: an ultrastructural study of peroxidase-positive phagolysosomes. Infect Immun 1986; 53:427-31. [PMID: 3015802 PMCID: PMC260893 DOI: 10.1128/iai.53.2.427-431.1986] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We have previously shown that human polymorphonuclear leukocytes (PMNs) killed organisms belonging to both human biovars of Chlamydia trachomatis. However, the mechanism of destruction was still unclear. We therefore conducted an ultrastructural and cytochemical study to investigate the mechanism of chlamydial degradation. PMNs were inoculated with the trachoma serovar B (B/TW-5/OT) or with the lymphogranuloma venereum serovar L2 (L2/434/Bu) for 15, 30, 60, or 120 min and then fixed and processed for transmission electron microscopy. Diaminobenzidine, a cytochemical marker, was used to demonstrate the localization of intracellular peroxidase. Ultrastructural evidence is presented showing the progressive degradation of chlamydiae over a 2-h period within peroxidase-positive phagolysosomes. Pretreatment of organisms with normal or immune serum was not required for the process of degradation.
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37
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Slepushkin VA, Grigor'ev VB, Starov AI, Klimenko SM, Kornilaeva GV. [Isolation and characteristics of endocytic vacuoles containing the influenza virus]. Vopr Virusol 1986; 31:167-72. [PMID: 2873686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Endocytic vacuoles (receptosomes) containing influenza virus were isolated from the cytoplasm of Ehrlich ascitic carcinoma cells and characterized. In the sucrose density gradient, the virus-containing material was detected in two peaks with a buoyant density of 1.175-1.16 and 1.155-1.135 g/cm3 with which the activity of marker enzymes of cell plasma membranes was associated. The virus was present in receptosomes in morphologically and electrophoretically intact condition. Examinations for the lipid composition of endocytic vacuoles showed the presence in their membranes of large amounts of cholesterol and glycolipids, particularly asialo-GM1 which, according to some authors may enhance the fusion of viral and cell membranes.
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Griffith GR, Consigli RA. Isolation and characterization of monopinocytotic vesicles containing polyomavirus from the cytoplasm of infected mouse kidney cells. J Virol 1984; 50:77-85. [PMID: 6321803 PMCID: PMC255585 DOI: 10.1128/jvi.50.1.77-85.1984] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Monopinocytotic vesicles containing polyomavirus were isolated from the cytoplasm of mouse kidney cells infected with polyomavirus using sucrose density gradients. Nonenclosed, membrane-associated virions released by the action of neuraminidase separated from vesicle-enclosed virions in the sucrose gradient. Marker enzyme assays indicated the derivation of the vesicle membrane from the plasma membrane of the cell. The 125I-labeled virus enclosed in the vesicle sedimented more slowly in the gradient and was not observed unless infection and endocytosis had occurred. Detergent treatment of virion-containing vesicles caused the release of polyomavirus with sedimentation properties similar to those of purified polyoma virions. In addition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of virion proteins from vesicles containing virions demonstrated patterns of proteins similar to those of purified intact virions. Electron microscopy confirmed the presence of single intact virions inside vesicles. The study of these monopinocytotic virion-containing vesicles represents a further step in elucidating the early events of polyomavirus infection.
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Abstract
The early steps of rabies virus (CVS) infection in vitro were studied in chicken embryo-related (CER) cells. The infection was monitored by looking for specific intracytoplasmic viral inclusions using anti-rabies fluorescein isothiocyanate at 24 h after the addition of virus. The attachment of rabies virus to CER cells was shown to be inhibited by pretreatment of the cells with neuraminidase. These cells recovered their susceptibility to rabies virus infection 6 h after removal of the enzyme. Treatment of CER cells with neuraminidase after the viral attachment step did not inhibit infection. The subsequent delivery of infectious virions into acid prelysosomal vacuoles or lysosomes was studied using lysosomotropic agents. Ammonium chloride and chloroquine were used to prevent the virus fusion step thus preventing infection. Both drugs were shown to inhibit the early steps of infection, NH4Cl having a much earlier effect than chloroquine. The two drugs had no effect on the attachment step nor did NH4Cl inhibit virus multiplication. The use of metabolic inhibitors (2-deoxy-D-glucose and sodium azide) shows that the entry of rabies virus into CER cells does not require the involvement of cellular energy processes. In electron microscopy studies, the presence of rabies virus particles was detected in coated pits and coated vesicles as well as in uncoated vesicles, and later in lysosomes. These data indicate that the mechanism by which rabies virus enters CER cells is probably through adsorptive endocytosis and does not require the participation of cellular metabolic active processes.
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40
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Popov VL, Barkhatova OI. [Interaction of Rickettsia akari with the host cell in vitro: multiplication, formation of spheroplast-like forms and its destruction in phagolyosomes]. Zh Mikrobiol Epidemiol Immunobiol 1984:23-7. [PMID: 6546830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
The electron microscopic study of the interaction of R. akari, strain CK, with the monolayer culture of L-cells was made 4 days after inoculation. Rickettsiae multiplied by transverse binary fission immediately in the cytoplasm of the cells and left the cells by gemmation, surrounded with plasmolemma and a fragment of the host cytoplasm. Alongside with multiplying rickettsiae, spheroplast-like rickettsiae and rickettsiae at the stage of destruction were regularly observed in phagolysosomes. The authors suggest that the normal interaction of rickettsiae with the host cell may be realized by three following routes (1) reproduction, (2) destruction in phagolysosomes and (3) formation of altered (anomalous) forms. The ability of the vegetative forms of rickettsiae and chlamydiae to yield spheroplast-like forms (the initial phase of bacterial L-transformation) indicates that these organisms are similar to bacteria and cannot be themselves regarded as L-forms.
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41
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Loginova NV, Cherednichenko IN, Viazov SO, Vanag KA, Zhdanov VM. [Infectious activity of cell fractions isolated from the brain of mice with scrapie]. Vopr Virusol 1983; 28:597-601. [PMID: 6686393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The agent of scrapie was found to induce clinically similar diseases in BALB/c and NIH mice but differing in the duration of the incubation period (155-180 days and 110-140 days, respectively) and pathomorphological manifestations. Differentiated examinations of a brain cell pool from mice with scrapie revealed more infectious activity not neutralized with nucleases and pronasa in membrane-free cell fractions than in fractions of slowly sedimenting membranes.
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42
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Zeichner SL. Isolation and characterization of macrophage phagosomes containing infectious and heat-inactivated Chlamydia psittaci: two phagosomes with different intracellular behaviors. Infect Immun 1983; 40:956-66. [PMID: 6852926 PMCID: PMC348145 DOI: 10.1128/iai.40.3.956-966.1983] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Infectious Chlamydia psittaci enters macrophages via a cytochalasin B-insensitive pathway in which chlamydia-containing phagosomes do not fuse with lysosomes; heat-inactivated C. psittaci enters macrophages via a route in which phagosomes do fuse with lysosomes. In an attempt to explain these differences, phagosomes containing infectious and heated chlamydiae were isolated from mouse macrophages by a procedure developed to isolate L-cell chlamydial phagosomes by rate zonal centrifugation. Macrophage phagosomes acted similarly to L-cell phagosomes on dextran and discontinuous sucrose gradients and exhibited similar detergent sensitivities. Total proteins of the two phagosomes were compared with each other, L-cell proteins, and surface-labeled proteins from macrophages. Both macrophage phagosome membranes had at least nine proteins with equal sodium dodecyl sulfate-polyacrylamide gel electrophoresis mobilities; some were the same as L-cell phagosome proteins. Each phagosome had at least one protein not seen in the other. Only two phagosome proteins had mobilities equal to macrophage plasma membrane proteins. Macrophage phagosomes containing infectious and heat-inactivated C. psittaci, although created by different entry mechanisms and destined for different intracellular fates, exhibited only a few differences in their proteins.
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Abstract
Irradiated L cells infected with Rickettsia tsutsugamushi were studied under the electron microscope to define the morphological growth pattern of the organism. For 2 days after inoculation, no rickettsiae were found either extra- or intracellularly; after 2 days multiple rickettsiae appeared within the host cells without morphological evidence of their entry. These observations showed that the rickettsiae within the cell were assembled in situ by segregation of portions of the granular cytoplasm and subsequent internal differentiation and surface membrane assembly of the segregated bodies. The protoplasmic (P) bodies, which seemed to be formed by shedding infected-cell granular cytoplasm, consistently appeared on the surface and within the phagosomes of the host cells. Rickettsiae were occasionally seen entering host cells in the later phase of infection; these were apparently the ones assembled within the P bodies. This suggested that the P bodies, and not the rickettsiae, were the major infectious particles that transmitted the rickettsial genetic substance among the host cells. On the basis of the present morphological observations, viral-type multiplication for R. tsutsugamushi is proposed.
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Abstract
Factors involved in the phagocytosis and entry into polymorphonuclear leukocytes (PMNs) of Rickettsia tsutsugamushi were studied by electron microscopy. R. tsutsugamushi propagated in baby hamster kidney cell cultures was incubated with guinea pig peritoneal PMNs in vitro at 35 degrees C. Structurally intact and degenerating rickettsiae were found in phagosomes, but only intact rickettsiae escaped phagosomes and specifically entered the glycogen-rich cytoplasm. The extraphagosomal cytoplasmic rickettsiae were found within 30 min after incubation; continued incubation for 4 h increased the rickettsial entry about fourfold as seen in ultrathin sections. Most rickettsiae in phagosomes were degenerating after 4 h of incubation. When incubated at 25 degrees C, no entry and very few phagocytized rickettsiae were observed. At 40 degrees C, rickettsial entry was greatly reduced, but more rickettsiae were found in phagosomes than at 35 degrees C. Preincubation of rickettsiae at 56 degrees C for 20 min with trypsin or with 2,4-dinitrophenol inhibited entry, but many rickettsiae were in phagosomes. Glutaraldehyde or formaldehyde fixation of rickettsiae and addition of 2-deoxyglucose, iodoacetamide, cytochalasin B, colchicine, or vinblastine inhibited all rickettsial uptake by PMNs. Acid phosphatase cytochemistry of infected PMNs revealed the enzyme activity only in phagosomes with degenerated rickettsiae and not in those with intact rickettsiae. These observations indicated that rickettsiae are passively phagocytized by PMNs, and only those that are intact actively escape from phagosomes, which selectively inhibits lysosomal fusion.
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Abstract
The obligate intracellular procaryote Chlamydia psittaci enters host cells by a mechanism similar to, but distinct from, conventional phagocytosis. To better understand chlamydial uptake, L-cell phagosomes containing a single chlamydial cell were isolated and studied. Two rounds of dextran rate-zonal gradient centrifugation of L cells homogenized 1 h after infection with C. psittaci yielded phagosomes relatively free of other membranous structures. In double-label experiments, the phagosomes were enriched over 40-fold for radioactivity derived from chlamydiae as compared with the initial homogenate. Several lines of evidence showed that the structures isolated on dextran gradients were chlamydial phagosomes. These structures and free chlamydiae banded at different positions on discontinuous sucrose gradients. The difference was destroyed by the nonionic detergent Nonidet P-40, which disrupts plasma membranes but has no effect on C. psittaci. Material labeled on the surface of the L-cell plasma membrane cosedimented with the phagosome fractions. Electron microscopy of these fractions revealed structures having the appearance of a chlamydial elementary body surrounded by a unit membrane. Sodium dodecyl sulfate-polyacrylamide gels of the phagosome membranes displayed 10 major protein bands, less than the total number of surface-labeled proteins in the L-cell plasma membrane. Seven of the proteins of phagosome membranes had electrophoretic mobilities corresponding to those of proteins exposed on the surface of L cells. Two of them were cleaved by both trypsin and chymotrypsin, enzymes that decrease the susceptibility of L cells to infection with C. psittaci. These proteins may therefore be involved in the attachment and ingestion of C. psittaci by L cells.
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Abstract
Interaction between influenza virus WSN strain and MDCK cells was studied by using spin-labeled phospholipids and electron microscopy. Envelope fusion was negligibly small at neutral pH but greatly activated in acidic media in a narrow pH range around 5.0. The half-time was less than 1 min at 37 degrees C at pH 5.0. Virus binding was almost independent of the pH. Endocytosis occurred with a half-time of about 7 min at 37 degrees C at neutral pH, and about 50% of the initially bound virus was internalized after 1 h. Electron micrographs showed binding of virus particles in coated pits in the microvillous surface of plasma membrane and endocytosis into coated vesicles. Chloroquine inhibited virus replication. The inhibition occurred when the drug was added not later than 10 min after inoculation. Chloroquine caused an increase in the lysosomal pH 4.9 to 6.1. The drug did not affect virus binding, endocytosis, or envelope fusion at pH 5.0. Electron micrographs showed many virus particles remaining trapped inside vacuoles even after 30 min at 37 degrees C in the presence of drug, in contrast to only a few particles after 10 min in vacuoles and secondary lysosomes in its absence. Virus replication in an artificial condition, i.e., brief exposure of the inoculum to acidic medium followed by incubation in neutral pH in the presence of chloroquine, was also observed. These results are discussed to provide a strong support for the infection mechanism of influenza virus proposed previously: virus uptake by endocytosis, fusion of the endocytosed vesicles with lysosome, and fusion of the virus envelope with the surrounding vesicle membrane in the secondary lysosome because of the low pH. This allows the viral genome to enter the target cell cytoplasm.
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Abstract
The early interactions of LLC-MK2 cell-grown noninfectious Sendai virus and a murine cell line, P815 mastocytoma ascitic cells, were studied by electron microscopy, using the ferritin-conjugated antibody technique with anti-virus glycoprotein serum. For comparison, the interactions of egg-grown infectious Sendai virus with the same cells were also examined. When noninfectious virus was adsorbed to the cells in the cold, the cell membranes become partially invaginated at the site of contact of adsorbed virions, but ferritin-conjugated antibodies did not penetrate into the areas of envelope-cell membrane association. This pattern of virus attachment was similar to that of infectious virus attachment. Upon subsequent incubation at 37 degrees C, most of the adsorbed noninfectious virions were taken into cytoplasmic vesicles and then degraded, although a few virions remained attached to the cell membrane. No evidence of fusion of envelopes of noninfectious virions was obtained. On the other hand, envelopes of infectious virions fused with the cell membrane, and the transferred viral antigens diffused on the cell surfaces and then decreased in number.
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Abstract
Intracellular survival of Chlamydia psittaci is in part dependent on the ability of the organism to thwart phagolysosome formation. Circumvention of phagolysosome fusion could be either localized to chlamydia-laden vacuoles or generalized to all phagosomes in the host cell. To determine which of these modes is in operation the ability of chlamydia elementary and reticulate bodies to protect Saccharomyces cerevisiae from degradation in macrophage phagolysosomes was examined via acridine orange and Giemsa staining. No statistically significant difference was evident between the amount of fusion observed in coinfected macrophages and those infected with yeast cells alone. This was ot dependent on some unique interaction between the chlamydia and the yeast cells since viable count studies to determine the protection of a second organism, Escherichia coli, also failed to show significantly different amounts of inactivation of the bacteria by macrophages in the presence of C. psittaci. Therefore, the inhibition of phagolysosome fusion is localized to chlamydia-laden phagosomes.
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