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de Oliveira Costa M, Dame MK. In Vitro Porcine (Explant) Colon Culture. Methods Mol Biol 2024; 2749:91-101. [PMID: 38133777 DOI: 10.1007/978-1-0716-3609-1_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Models have been extensively used to investigate disease pathogenesis. Animal models are costly and require extensive logistics for animal care, and samples are not always suitable for different analytical techniques or to answer the research question. In vitro cell culture models are generally focused on recreating a specific characteristic of an organ and are limited to a single cell population that does not display the characteristic tissue architecture of the source organ. In addition, such models do not account for the many interactions between pathogens and the diverse cell subsets that are normally present in a given organ. Conclusions based on conventional 2D cell culture methods are limited, requiring extrapolation from a reductionist model to understand in vivo events. In vitro organ culture (IVOC) offers a way to overcome some of these limitations. Explants conserve important in vivo characteristics, such as different cell types and complex tissue architecture. This in vitro (ex vivo) organ culture protocol of the swine large intestine aims at maintaining viable colonic mucosa for up to 5 days. The protocol described herein applies a combination of methods used for immortalized cell culture and stem cell stimulation to support the physiological cellular flow inherent of the intestinal mucosa. Required equipment includes a hyperoxic chamber and culture at the air-liquid interface.
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Affiliation(s)
- Matheus de Oliveira Costa
- Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
- Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
| | - Michael K Dame
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, University of Michigan, Ann Arbor, MI, USA
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2
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Xiao N, Li J, Li M, Hu Y, Lin H, Fan H. Preparation and Characterization of a New Monoclonal Antibody Specific Against Lawsonia intracellularis and Its Application in Indirect Immunofluorescence and Immunocytochemistry Assay. Front Vet Sci 2021; 8:753610. [PMID: 34912873 PMCID: PMC8667467 DOI: 10.3389/fvets.2021.753610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/21/2021] [Indexed: 12/31/2022] Open
Abstract
Proliferative enteropathy (PE) is an infectious enteric disease caused by Lawsonia intracellularis (L. intracellularis) and is endemic in pig herds worldwide. However, a L. intracellularis-specific monoclonal antibody plays an important role in the evaluation of L. intracellularis infection in vitro. Therefore, the objective of this study was to produce and identify the characteristics of a new monoclonal antibody against the outer membrane protein (Omp2) of L. intracellularis and apply it in an indirect immunofluorescence assay (IFA) and immunocytochemistry (IHC). The results indicated that three highly specific monoclonal antibodies against the Omp2 protein (4D9, 3G2, and 7G5) of L. intracellularis were obtained by using purified Omp2 as an immunogen, the titers of ascitic fluids of 4D9, 3G2, and 7G5 cells were 1:2,048,000, 1:512,000, and 1:256,000, respectively. IFA analysis showed that the 4D9, 3G2, and 7G5 have no cross-reactivity with other enteric bacteria commonly found in the ilea of pigs or closely related to L. intracellularis, such as Desulfovibrio, Bilophila wadsworthia (B. wadsworthia), Salmonella choleraesuis (S. choleraesuis), Salmonella typhimurium (S. typhimurium), Escherichia coli (E. coli), and Brachyspira hyodysenteriae (B. hyodysenteriae). IFA and IHC results indicated that the monoclonal antibodies can be successfully used as primary antibodies to detect L. intracellularis in infected cells and in the crypt of the ileum from infected tissues of PE. Our findings suggested that the new monoclonal antibody specific against L. intracellularis will be useful for the evaluation of L. intracellularis infection in vivo and in vitro.
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Affiliation(s)
- Ning Xiao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Jiannan Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Minxue Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Yuting Hu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Huixing Lin
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Hongjie Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
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Bacillus amyloliquefaciens SC06 Induced AKT-FOXO Signaling Pathway-Mediated Autophagy to Alleviate Oxidative Stress in IPEC-J2 Cells. Antioxidants (Basel) 2021; 10:antiox10101545. [PMID: 34679680 PMCID: PMC8533163 DOI: 10.3390/antiox10101545] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/09/2021] [Accepted: 09/25/2021] [Indexed: 11/16/2022] Open
Abstract
Autophagy is a conserved proteolytic mechanism, which degrades and recycles damaged organs and proteins in cells to resist external stress. Probiotics could induce autophagy; however, its underlying molecular mechanisms remain elusive. Our previous study has found that BaSC06 could alleviate oxidative stress by inducing autophagy in rats. This research aimed to verify whether Bacillus amyloliquefaciens SC06 can induce autophagy to alleviate oxidative stress in IPEC-J2 cells, as well as explore its mechanisms. IPEC-J2 cells were first pretreated with 108 CFU/mL BaSC06, and then were induced to oxidative stress by the optimal dose of diquat. The results showed that BaSC06 significantly triggered autophagy, indicated by the up-regulation of LC3 and Beclin1 along with downregulation of p62 in IPEC-J2 cells. Further analysis revealed that BaSC06 inhibited the AKT-FOXO signaling pathway by inhibiting the expression of p-AKT and p-FOXO and inducing the expression of SIRT1, resulting in increasing the transcriptional activity of FOXO3 and gene expression of the ATG5-ATG12 complex to induce autophagy, which alleviated oxidative stress and apoptosis. Taken together, BaSC06 can induce AKT-FOXO-mediated autophagy to alleviate oxidative stress-induced apoptosis and cell damage, thus providing novel theoretical support for probiotics in the prevention and treatment of oxidative damage.
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Pereira CER, Resende TP, Armién AG, Laub RP, Vannucci FA, Santos RL, Gebhart CJ, Guedes RMC. Survival of Lawsonia intracellularis in porcine peripheral blood monocyte-derived macrophages. PLoS One 2020; 15:e0236887. [PMID: 32735621 PMCID: PMC7394435 DOI: 10.1371/journal.pone.0236887] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/15/2020] [Indexed: 11/18/2022] Open
Abstract
Lawsonia intracellularis, an obligately intracellular enteric bacterium, infects intestinal epithelial cells, but may also be found within macrophages in the intestinal lamina propria of affected pigs. Macrophages play an important role in host defense against infectious agents, but the role of this cell in L. intracellularis infection is not well understood. The aim of this study was to evaluate the permissibility of macrophages to L. intracellularis infection in vitro. Pure culture of L. intracellularis was added to swine peripheral blood monocyte-derived macrophages. Viability of intracytoplasmic L. intracellularis was evaluated at different time points by transmission electron microscopy (TEM). Potential replication of L. intracellularis in macrophages was also evaluated by qPCR. By TEM, phagocytosis L. intracellularis within of phagolysosomes were observed 1-hour post-infection (hpi) and bacterial structures in binary fission at 48 hpi. The number of intracellular bacteria was determined at 1, 4, 24, 48, and 72 hpi by qPCR in infected macrophages and compared to the number of intracellular bacteria from culture in McCoy cells. In both cell lines, the amount of L. intracellularis was decreased at 4 hpiand increased at 24 hpi. The number of intracellular bacteria continued to increase in McCoy cells over time. This is the first study showing interaction, survival and propagation of L. intracellularis in macrophages. These findings are critical to establish an experimental model for future studies of the pathogenesis of porcine proliferative enteropathy and the potential persistence of L. intracellularis in macrophages during chronic infections.
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Affiliation(s)
- Carlos Eduardo Real Pereira
- Department of Veterinary Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Talita Pilar Resende
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Aníbal G. Armién
- Department of Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
- Ultrastructural Pathology Unit, Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Ricardo Pereira Laub
- Department of Veterinary Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Fabio Augusto Vannucci
- Department of Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Renato Lima Santos
- Department of Veterinary Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Connie Jane Gebhart
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
- Department of Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Roberto Mauricio Carvalho Guedes
- Department of Veterinary Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
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Resende TP, Medida RL, Guo Y, Vannucci FA, Saqui-Salces M, Gebhart C. Evaluation of mouse enteroids as a model for Lawsonia intracellularis infection. Vet Res 2019; 50:57. [PMID: 31324204 PMCID: PMC6642515 DOI: 10.1186/s13567-019-0672-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 07/05/2019] [Indexed: 12/16/2022] Open
Abstract
Lawsonia intracellularis, an obligate intracellular bacterium, is an important enteric pathogen in pig herds and horse farms worldwide. The hallmark feature of L. intracellularis infection is the proliferation of epithelial cells in intestinal crypts. A major limitation to the study of L. intracellularis infection is the lack of an in vitro model that reproduces the changes observed in proliferative enteropathy. Here we investigated the suitability of mouse enteroids as a model to study L. intracellularis infection. Mouse enteroids were microinjected with L. intracellularis, filter-sterilized L. intracellularis culture supernatant, or sterile cell culture media (DMEM). L. intracellularis antigen was detected in mouse enteroids by immunohistochemistry and was located mostly in the basal region of the epithelium. There was no differential growth of enteroids among treatment groups, and cellular proliferation was not increased in L. intracellularis-infected enteroids in relation to non-infected enteroids based on immunofluorescence staining. L. intracellularis infection did not induce changes in gene expression of Ki-67 (proliferation marker), Sox9 (marker for transit amplifying cells) and Muc2 (marker for goblet cells). These results indicate that although L. intracellularis antigen is detectable in mouse enteroids, indicating susceptibility to infection, mouse enteroids fail to replicate the cellular proliferation and gene expression changes observed in proliferative enteropathy. Nevertheless, we have successfully demonstrated that mouse enteroids can be used to model days-long intracellular pathogen infection, serving as potential models for the study of other pathogens of interest in veterinary medicine.
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Affiliation(s)
- Talita Pilar Resende
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA.
| | - Ramya Lekha Medida
- Department of Animal Science, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, St. Paul, MN, 55108, USA
| | - Yue Guo
- Department of Animal Science, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, St. Paul, MN, 55108, USA
| | - Fabio A Vannucci
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA
| | - Milena Saqui-Salces
- Department of Animal Science, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, St. Paul, MN, 55108, USA
| | - Connie Gebhart
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA.,Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108, USA
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6
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Abstract
Models have been extensively used to investigate disease pathogenesis. Animal models are costly, require extensive logistics for animal care, and samples are not always suitable for different analytical techniques or to answer the research question. In vitro cell culture models are generally focused on recreating a specific characteristic of an organ, and are limited to a single cell population that does not display the characteristic tissue architecture of the source organ. In addition, such models do not account for the many interactions between pathogens and the diverse cell subsets that are normally present in a given organ. Conclusions based on conventional 2D cell culture methods are limited, requiring extrapolation from a reductionist model to understand in vivo events. In vitro organ culture (IVOC) offers a way to overcome some of these limitations. Explants conserve important in vivo characteristics, such as different cell types and complex tissue architecture. This in vitro (ex vivo) organ culture protocol of the swine large intestine aims at maintaining viable colonic mucosa for up to 5 days. The protocol described herein applies a combination of methods used for immortalized cell culture and stem cell stimulation to support the physiological cellular flow inherent of the intestinal mucosa. Required equipment includes a hyperoxic chamber and culture at the air-liquid interface.
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Affiliation(s)
- Matheus O Costa
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada. .,Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
| | - Janet E Hill
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Michael K Dame
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, University of Michigan, Ann Arbor, MI, USA
| | - John C S Harding
- Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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Leite FL, Vasquez E, Gebhart CJ, Isaacson RE. The effects of Lawsonia intracellularis, Salmonella enterica serovar Typhimurium and co-infection on IL-8 and TNFα expression in IPEC-J2 cells. Vet Microbiol 2019; 231:76-79. [PMID: 30955828 DOI: 10.1016/j.vetmic.2019.02.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 02/06/2019] [Accepted: 02/28/2019] [Indexed: 01/03/2023]
Abstract
Lawsonia intracellularis is among the most important enteric pathogens of swine and has been shown to be a risk factor for increased Salmonella enterica shedding. S. enterica serovar Typhimurium, in addition to being a significant pathogen of swine, also remains one of the most common causes of foodborne illness worldwide. Inflammation and the expression of IL8 and TNFα are an important process in the establishment of S. Typhimurium infection. Yet the effect of L. intracellularis on the expression of these cytokines by enterocytes, the niche both pathogens occupy during infection, is poorly understood. In this study we compared cytokine gene expression between singly and dually infected IPEC-J2 cells, a non-transformed porcine enterocyte cell line. Our results show that L. intracellularis leads to increased expression of IL8 and TNFα and has an additive effect on their expression in co-infection. The increase in expression of inflammatory cytokines may be one mechanism by which L. intracellularis favors S. Typhimurium infection.
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Affiliation(s)
- Fernando L Leite
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, USA.
| | - Erika Vasquez
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, USA.
| | - Connie J Gebhart
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, USA.
| | - Richard E Isaacson
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, USA.
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Resende TP, Pereira CER, Daniel AGDS, Vasquez E, Saqui-Salces M, Vannucci FA, Gebhart CJ. Effects of Lawsonia intracellularis infection in the proliferation of different mammalian cell lines. Vet Microbiol 2018; 228:157-164. [PMID: 30593362 DOI: 10.1016/j.vetmic.2018.11.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 10/27/2022]
Abstract
Lawsonia intracellularis is an obligate intracellular bacterium that causes proliferative enteropathy in various animal species. While cellular proliferation of intestinal cells is recognized as the hallmark of L. intracellularis infection in vivo, it has not been demonstrated in in vitro models. In order to assay the effect of L. intracellularis, various cell lines were infected with pathogenic and non-pathogenic passages of the bacterium. Because of the high proliferative rate of these cell lines, serum deprivation, which is known to reduce proliferation, was applied to each of the cell lines to allow the observation of proliferation induced by L. intracellularis. Using antibodies for Ki-67 and L. intracellularis in dual immunofluorescence staining, we observed that L. intracellularis was more frequently observed in proliferating cells. Based on wound closure assays and on the amount of eukaryotic DNA content measured over time, we found no indication that cell lines infected with L. intracellularis increased proliferation and migration when compared to non-infected cells (p > 0.05). Cell arrest due to decreased serum in the culture media was cell-line dependent. Taken together, our findings provide data to support and expand previous subjective observations of the absence of in vitro proliferation caused by L. intracellularis in cell cultures and confirm that cell lines infected by L. intracellularis fail to serve as adequate models for understanding the cellular changes observed in proliferative enteropathy-affected intestines.
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Affiliation(s)
- Talita Pilar Resende
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA.
| | - Carlos Eduardo Real Pereira
- Department of Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, PO Box 567, Belo Horizonte, Minas Gerais 31270-901, Brazil
| | - Amanda Gabrielle de Souza Daniel
- Department of Clinic and Surgery, Veterinary School, Universidade Federal de Minas Gerais, PO Box 567, Belo Horizonte, Minas Gerais 31270-901, Brazil
| | - Erika Vasquez
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
| | - Milena Saqui-Salces
- Department of Animal Science, College of Food, Agricultural and Natural Resource Sciences (CFANS), University of Minnesota, St. Paul, MN 55108, USA
| | - Fabio A Vannucci
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
| | - Connie Jane Gebhart
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA; Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
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Pearce SC, Coia HG, Karl JP, Pantoja-Feliciano IG, Zachos NC, Racicot K. Intestinal in vitro and ex vivo Models to Study Host-Microbiome Interactions and Acute Stressors. Front Physiol 2018; 9:1584. [PMID: 30483150 PMCID: PMC6240795 DOI: 10.3389/fphys.2018.01584] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/23/2018] [Indexed: 12/16/2022] Open
Abstract
The gut microbiome is extremely important for maintaining homeostasis with host intestinal epithelial, neuronal, and immune cells and this host-microbe interaction is critical during times of stress or disease. Environmental, nutritional, and cognitive stress are just a few factors known to influence the gut microbiota and are thought to induce microbial dysbiosis. Research on this bidirectional relationship as it pertains to health and disease is extensive and rapidly expanding in both in vivo and in vitro/ex vivo models. However, far less work has been devoted to studying effects of host-microbe interactions on acute stressors and performance, the underlying mechanisms, and the modulatory effects of different stressors on both the host and the microbiome. Additionally, the use of in vitro/ex vivo models to study the gut microbiome and human performance has not been researched extensively nor reviewed. Therefore, this review aims to examine current evidence concerning the current status of in vitro and ex vivo host models, the impact of acute stressors on gut physiology/microbiota as well as potential impacts on human performance and how we can parlay this information for DoD relevance as well as the broader scientific community. Models reviewed include widely utilized intestinal cell models from human and animal models that have been applied in the past for stress or microbiology research as well as ex vivo organ/tissue culture models and new innovative models including organ-on-a-chip and co-culture models.
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Affiliation(s)
- Sarah C Pearce
- Performance Nutrition Team, Combat Feeding Directorate, Natick Soldier Research, Development and Engineering Center, Natick, MA, United States
| | - Heidi G Coia
- National Research Council, The National Academies of Sciences, Engineering, and Medicine, Washington, DC, United States.,711th Human Performance Wing, Airforce Research Laboratory, Airman Systems Directorate, Human-Centered ISR Division, Molecular Mechanisms Branch, Wright-Patterson Air Force Base, Dayton, OH, United States
| | - J P Karl
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States
| | - Ida G Pantoja-Feliciano
- Soldier Protection and Optimization Directorate, Natick Soldier Research, Development and Engineering Center, Natick, MA, United States
| | - Nicholas C Zachos
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Kenneth Racicot
- Performance Nutrition Team, Combat Feeding Directorate, Natick Soldier Research, Development and Engineering Center, Natick, MA, United States
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Guedes RMC, Machuca MA, Quiroga MA, Pereira CER, Resende TP, Gebhart CJ. Lawsonia intracellularis in Pigs: Progression of Lesions and Involvement of Apoptosis. Vet Pathol 2017. [PMID: 28622490 DOI: 10.1177/0300985817698206] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The purpose of this study was to follow the progression of gross and histologic lesions and apoptosis events in Lawsonia intracellularis-infected enterocytes through the course of the disease, proliferative enteropathy (PE). Thirty 5-week-old pigs were divided into 2 groups: 20 challenged and 10 control animals. Groups of 3 pigs, 2 challenged and 1 control, were euthanized at 1, 3, 5, 8, 11, 15, 19, 24, 29, and 35 days after inoculation. Complete necropsies were performed with gross evaluation. Tissue samples from different sites of the gastrointestinal tract and other visceral organs were collected for routine histologic staining and for immunohistochemistry (IHC) for L. intracellularis. In addition, caspase-3, terminal deoxyuridine nick-end labeling assay, and electron microscopy were performed in ileum samples. Macroscopic and histologic lesions suggestive of PE were first detected 11 days after infection and continued through day 24. L. intracellularis antigen was first detected in the intestine by IHC on day 5 after inoculation, and the bacterium was first detected by transmission electron microscopy on day 15. Positive IHC staining for [L. intracellularis] and enterocyte proliferation, but no gross lesion, were detected on day 29. All 3 pigs euthanized on day 35 were grossly and histologically normal and IHC negative. Hyperplastic crypts in challenge pigs had more apoptotic cells on days 15, 19, and 24 postinfection ( P < .05) compared to control pigs. Our results demonstrated the progression of lesions and infection by L. intracellularis and that inhibition of enterocyte apoptosis is not involved in the pathogenesis of proliferative enteropathy.
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Affiliation(s)
- Roberto M C Guedes
- 1 Veterinary School, Department of Clinic and Surgery, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Mariana A Machuca
- 2 Department of Veterinary Pathology, Faculty of Veterinary Science, La Plata National University, Buenos Aires, Argentina
| | - Maria A Quiroga
- 2 Department of Veterinary Pathology, Faculty of Veterinary Science, La Plata National University, Buenos Aires, Argentina
| | - Carlos E Real Pereira
- 1 Veterinary School, Department of Clinic and Surgery, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Talita P Resende
- 3 Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
| | - Connie J Gebhart
- 3 Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
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Use of flow cytometry and PCR analysis to detect 5-carboxyfluoroscein-stained obligate intracellular bacteria Lawsonia intracellularis invasion of McCoy cells. J Microbiol Methods 2016; 126:60-6. [PMID: 27154728 DOI: 10.1016/j.mimet.2016.04.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 04/29/2016] [Indexed: 11/23/2022]
Abstract
In this study, we describe a method to quantify invasion of obligate intracellular bacteria, Lawsonia intracellularis, inside McCoy cells. In immunological research, the cell-permeable fluorescent dye 5'-carboxyfluoroscein succidyl ester (CFSE) is commonly used to quantify eukaryotic cellular proliferation. Instead of using it in this traditional way, we stained L. intracellularis with CFSE dye prior to infection of McCoy cells. Flow cytometry was performed to quantify the percentage of eukaryotic cells which had taken up or were associated with fluorescent bacteria. As obligate intracellular bacteria, they cannot replicate outside of eukaryotic cells and thus qPCR analysis was used to quantify bacterial growth. Indirectly, PCR analysis confirmed invasion rather than adherence to the McCoy cell surface. Fluorescent activated cell sorting (FACS) was used to sort the CFSE(+) (i.e. infected) McCoy cells from the CFSE(-) (i.e. non-infected) McCoy cells and confocal microscopy was used to confirm bacterial invasion and cytosolic localization of CFSE-L. intracellularis. To show that this approach could be used in conjunction with functional assays, we investigated the effect that serum antibodies had on CFSE-bacterial invasion and growth. Instead of blocking invasion, rabbit hyperimmune serum augmented invasion of the bacteria inside McCoy cells and qPCR analysis confirmed bacterial growth over the course of 5days. We conclude that CFSE-labeling of bacteria and qPCR can be used to track and quantify bacterial invasion and may be a valuable tool for studying the invasive properties of bacteria, especially if commercial antibodies are not available. This approach may be adapted for use in other obligate intracellular bacteria and intracellular pathogens.
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Riber U, Heegaard PM, Cordes H, Ståhl M, Jensen TK, Jungersen G. Vaccination of pigs with attenuated Lawsonia intracellularis induced acute phase protein responses and primed cell-mediated immunity without reduction in bacterial shedding after challenge. Vaccine 2015; 33:156-62. [DOI: 10.1016/j.vaccine.2014.10.084] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 10/24/2022]
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13
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Page AE, Slovis NM, Horohov DW. Lawsonia intracellularis and Equine Proliferative Enteropathy. Vet Clin North Am Equine Pract 2014; 30:641-58. [DOI: 10.1016/j.cveq.2014.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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14
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Vannucci FA, Gebhart CJ. Recent Advances in Understanding the Pathogenesis of Lawsonia intracellularis Infections. Vet Pathol 2014; 51:465-77. [DOI: 10.1177/0300985813520249] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Proliferative enteropathy is an infectious disease caused by an obligate intracellular bacterium, Lawsonia intracellularis, and characterized by thickening of the intestinal epithelium due to enterocyte proliferation. The disease is endemic in swine herds and has been occasionally reported in various other species. Furthermore, outbreaks among foals began to be reported on breeding farms worldwide within the past 5 years. Cell proliferation is directly associated with bacterial infection and replication in the intestinal epithelium. As a result, mild to severe diarrhea is the major clinical sign described in infected animals. The dynamics of L. intracellularis infection in vitro and in vivo have been well characterized, but little is known about the genetic basis for the pathogenesis or ecology of this organism. The present review focuses on the recent advances regarding the pathogenesis and host-pathogen interaction of L. intracellularis infections.
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Affiliation(s)
- F. A. Vannucci
- Department of Veterinary and Biomedical Science, College of Veterinary Medicine, University of Minnesota, St Paul, MN, USA
| | - C. J. Gebhart
- Department of Veterinary and Biomedical Science, College of Veterinary Medicine, University of Minnesota, St Paul, MN, USA
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Vannucci FA, Foster DN, Gebhart CJ. Laser microdissection coupled with RNA-seq analysis of porcine enterocytes infected with an obligate intracellular pathogen (Lawsonia intracellularis). BMC Genomics 2013; 14:421. [PMID: 23800029 PMCID: PMC3718617 DOI: 10.1186/1471-2164-14-421] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 06/18/2013] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Lawsonia intracellularis is an obligate intracellular bacterium and the etiologic agent of proliferative enteropathy. The disease is endemic in pigs, emerging in horses and has been described in various other species including nonhuman primates. Cell proliferation is associated with bacterial replication in enterocyte cytoplasm, but the molecular basis of the host-pathogen interaction is unknown. We used laser capture microdissection coupled with RNA-seq technology to characterize the transcriptional responses of infected enterocytes and the host-pathogen interaction. RESULTS Proliferative enterocytes was associated with activation of transcription, protein biosynthesis and genes acting on the G1 phase of the host cell cycle (Rho family). The lack of differentiation in infected enterocytes was demonstrated by the repression of membrane transporters related to nutrient acquisition. The activation of the copper uptake transporter by infected enterocytes was associated with high expression of the Zn/Cu superoxide dismutase by L. intracellularis. This suggests that the intracellular bacteria incorporate intracytoplasmic copper and express a sophisticated mechanism to cope with oxidative stress. CONCLUSIONS The feasibility of coupling microdissection and RNA-seq was demonstrated by characterizing the host-bacterial interactions from a specific cell type in a heterogeneous tissue. High expression of L. intracellularis genes encoding hypothetical proteins and activation of host Rho genes infers the role of unrecognized bacterial cyclomodulins in the pathogenesis of proliferative enteropathy.
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Affiliation(s)
- Fabio A Vannucci
- Department of Veterinary and Biomedical Science , College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
| | - Douglas N Foster
- Department of Animal Science, College of Food, Agricultural and Natural Resource Science, University of Minnesota, St. Paul, MN, USA
| | - Connie J Gebhart
- Department of Veterinary and Biomedical Science , College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
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Cordes H, Riber U, Jensen TK, Jungersen G. Cell-mediated and humoral immune responses in pigs following primary and challenge-exposure to Lawsonia intracellularis. Vet Res 2012; 43:9. [PMID: 22316065 PMCID: PMC3313852 DOI: 10.1186/1297-9716-43-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 02/08/2012] [Indexed: 11/10/2022] Open
Abstract
To investigate immune responses upon re-infection with Lawsonia intracellularis, local and peripheral humoral and cell-mediated immune responses to primary and challenge inoculations were studied in 22 pigs. Pigs were orally inoculated with virulent L. intracellularis at the age of 5-6 weeks, treated with antibiotics and challenged with a re-inoculation (RE) at the age of 12 weeks. Treatment control (TC) pigs received only the primary inoculation and challenge control (CC) pigs received only the secondary inoculation at 12 weeks of age. Following this regimen, all RE pigs were protected against the re-infection as defined by reduced colonisation and pathology of intestinal mucosa, absence of bacterial shedding and without increase in serum acute phase protein response. In the protected RE pigs, serum IgG responses were variable with both high and low responders. Serum IgA responses were not boosted by the re-inoculation, since identical intestinal IgA responses developed in response to the inoculation in both the susceptible CC pigs and the protected RE pigs. A memory recall cell-mediated immune response developed in RE pigs which was significantly stronger compared to the primary response in age-matched CC pigs as assessed by whole blood IFN-γ assay and by calculation of IFN-γ integrated median fluorescence intensity (iMFI) after flow cytometry. The major IFN-γ producing cells were identified as CD8+ and CD4+CD8+ double positive lymphocytes. The results indicate that cell-mediated immune responses are likely mediators of protective immunity against L. intracellularis, with CD8+ effector cells and CD4+CD8+ double positive memory T cells as main contributors to the antigen-specific IFN-γ production.
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Affiliation(s)
- Henriette Cordes
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1790 Copenhagen V, Denmark.
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Brosnahan AJ, Brown DR. Porcine IPEC-J2 intestinal epithelial cells in microbiological investigations. Vet Microbiol 2011; 156:229-37. [PMID: 22074860 DOI: 10.1016/j.vetmic.2011.10.017] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Revised: 10/12/2011] [Accepted: 10/14/2011] [Indexed: 11/30/2022]
Abstract
IPEC-J2 cells are porcine intestinal columnar epithelial cells that were isolated from neonatal piglet mid-jejunum. This cell line forms polarized monolayers with high transepithelial electrical resistance when cultured on 0.4 μm pore-size filters. The cell line is unique in that it is derived from small intestinal tissue (compared to the common human colon-derived lines HT-29, T84, and Caco-2) and is not transformed (compared to the porcine small intestinal line, IPI-2I). Porcine intestinal epithelial cells more closely mimic human physiology than analogous rodent cell lines (e.g. IEC-6 or IEC-18), which is important in studies of zoonotic infections; in addition, they provide specificity to study porcine-derived infections. IPEC-J2 cells are increasingly being used in microbiological studies to examine the interactions of various animal and human pathogens, including Salmonella enterica and pathogenic Escherichia coli, with intestinal epithelial cells. The IPEC-J2 cell line has also been employed in some probiotic studies, in which the cells have been used as an initial screening tool for adhesiveness and anti-inflammatory properties of the potential probiotic microorganisms. The validity of these studies is not clear as follow-up studies to assess the efficacy of the probiotics in vivo have not been published to date. The aims of this review are to provide a comprehensive overview of the microbiological studies that have been conducted with IPEC-J2 cells and a reference guide of key cellular and immune markers that have been identified in this cell line that may prove to be useful in future studies.
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Affiliation(s)
- Amanda J Brosnahan
- Department of Veterinary and Biomedical Sciences, University of Minnesota, College of Veterinary Medicine, 295 Animal Science/Veterinary Medicine, 1988 Fitch Ave, Saint Paul, MN 55108, USA.
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Xu S, Zhang C, Miao Y, Gao J, Xu D. Effector prediction in host-pathogen interaction based on a Markov model of a ubiquitous EPIYA motif. BMC Genomics 2010; 11 Suppl 3:S1. [PMID: 21143776 PMCID: PMC2999339 DOI: 10.1186/1471-2164-11-s3-s1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background Effector secretion is a common strategy of pathogen in mediating host-pathogen interaction. Eight EPIYA-motif containing effectors have recently been discovered in six pathogens. Once these effectors enter host cells through type III/IV secretion systems (T3SS/T4SS), tyrosine in the EPIYA motif is phosphorylated, which triggers effectors binding other proteins to manipulate host-cell functions. The objectives of this study are to evaluate the distribution pattern of EPIYA motif in broad biological species, to predict potential effectors with EPIYA motif, and to suggest roles and biological functions of potential effectors in host-pathogen interactions. Results A hidden Markov model (HMM) of five amino acids was built for the EPIYA-motif based on the eight known effectors. Using this HMM to search the non-redundant protein database containing 9,216,047 sequences, we obtained 107,231 sequences with at least one EPIYA motif occurrence and 3115 sequences with multiple repeats of the EPIYA motif. Although the EPIYA motif exists among broad species, it is significantly over-represented in some particular groups of species. For those proteins containing at least four copies of EPIYA motif, most of them are from intracellular bacteria, extracellular bacteria with T3SS or T4SS or intracellular protozoan parasites. By combining the EPIYA motif and the adjacent SH2 binding motifs (KK, R4, Tarp and Tir), we built HMMs of nine amino acids and predicted many potential effectors in bacteria and protista by the HMMs. Some potential effectors for pathogens (such as Lawsonia intracellularis, Plasmodium falciparum and Leishmania major) are suggested. Conclusions Our study indicates that the EPIYA motif may be a ubiquitous functional site for effectors that play an important pathogenicity role in mediating host-pathogen interactions. We suggest that some intracellular protozoan parasites could secrete EPIYA-motif containing effectors through secretion systems similar to the T3SS/T4SS in bacteria. Our predicted effectors provide useful hypotheses for further studies.
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Affiliation(s)
- Shunfu Xu
- Department of Gastroenterology, the First Affiliated Hospital of Nanjing Medical University, Jiangsu 210029, China.
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Rasschaert K, Devriendt B, Favoreel H, Goddeeris BM, Cox E. Clathrin-mediated endocytosis and transcytosis of enterotoxigenic Escherichia coli F4 fimbriae in porcine intestinal epithelial cells. Vet Immunol Immunopathol 2010; 137:243-50. [PMID: 20580439 DOI: 10.1016/j.vetimm.2010.05.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 05/25/2010] [Accepted: 05/28/2010] [Indexed: 11/24/2022]
Abstract
Enterotoxigenic Escherichia coli (ETEC) cause severe diarrhea in neonatal and recently weaned piglets. Previously, we demonstrated that oral immunization of F4 receptor positive piglets with purified F4 fimbriae induces a protective F4-specific intestinal immune response. However, in F4 receptor negative animals no F4-specific immune response can be elicited, indicating that the induction of an F4-specific mucosal immune response upon oral immunisation is receptor-dependent. Although F4 fimbriae undergo transcytosis across the intestinal epithelium in vivo, the endocytosis pathways used remain unknown. In the present study, we characterized the internalization of F4 fimbriae in the porcine intestinal epithelial cell line IPEC-J2. The results in the present study demonstrate that F4 fimbriae are internalized through a clathrin-dependent pathway. Furthermore, our results suggest that F4 fimbriae are transcytosed across differentiated IPEC-J2 cells. This receptor-dependent transcytosis of F4 fimbriae may explain the immunogenicity of these fimbriae upon oral administration in vivo.
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Affiliation(s)
- Kristien Rasschaert
- Laboratory of Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
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Drozd M, Kassem II, Gebreyes W, Rajashekara G. A quantitative polymerase chain reaction assay for detection and quantification of Lawsonia intracellularis. J Vet Diagn Invest 2010; 22:265-9. [PMID: 20224090 DOI: 10.1177/104063871002200218] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Lawsonia intracellularis, a causative agent of porcine proliferative enteropathy, is an obligate intracellular bacterium that is difficult to culture, propagate, and quantify. The intestinal epithelial cell line (IEC-18, derived from rat small intestine crypt cells) has been used to isolate and propagate this pathogen. However, the lack of rapid and simple quantification methods has led to mixed results when using the rat cell line, complicating Lawsonia studies. To overcome these limitations, a SYBR green quantitative polymerase chain reaction (qPCR) assay targeting a unique hypothetical protein was developed for detecting and quantifying L. intracellularis in IEC-18 rat epithelial cells, porcine fecal samples collected from different farms, and experimentally infected pigs. The method was optimized to detect as few as 3 copies per qPCR reaction of the bacterium growing in IEC-18 cells, providing a new and necessary approach to assess the growth of L. intracellularis in these cell lines. Furthermore, the qPCR assay was successful in detecting L. intracellularis in fecal samples collected from pigs with and without a history of Lawsonia infections, as well as in experimentally infected pigs, which further confirmed the suitability of the qPCR assay for studying the epidemiology of this pathogen.
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Affiliation(s)
- Mary Drozd
- Food Animal Health Research Program, Ohio Agricultural Research Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH 44691, USA
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Boutrup TS, Schauser K, Agerholm JS, Jensen TK. Application of a pig ligated intestinal loop model for early Lawsonia intracellularis infection. Acta Vet Scand 2010; 52:17. [PMID: 20181246 PMCID: PMC2843685 DOI: 10.1186/1751-0147-52-17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 02/24/2010] [Indexed: 11/18/2022] Open
Abstract
Background Porcine proliferative enteropathy in pigs is caused by the obligate, intracellular bacterium Lawsonia intracellularis. In vitro studies have shown close bacterium-cell interaction followed by cellular uptake of the bacterium within 3 h post inoculation (PI). However, knowledge of the initial in vivo interaction between porcine intestinal epithelium and the bacterium is limited. The aims of the present study were to evaluate the usefulness of a ligated small intestinal loop model to study L. intracellularis infections and to obtain information on the very early L. intracellularis-enterocyte interactions. Methods A ligated small intestinal loop model using three different L. intracellularis inocula was applied to 10-11-week-old pigs. The inocula were 1) wild type bacteria derived from overnight incubation of L. intracellularis bacteria from spontaneous disease, 2) crude vaccine bacteria (Enterisol® Ileitis Vet), and 3) vaccine bacteria propagated in cell culture. The bacteria-enterocyte interaction was visualised using immunohistochemistry on specimens derived 1, 3 and 6 h PI respectively. Results Although at a low level, close contact between bacteria and the enterocyte brush border including intracellular uptake of bacteria in mature enterocytes was seen at 3 and 6 h PI for the vaccine and the propagated vaccine inocula. Interaction between the wild-type bacteria and villus enterocytes was scarce and only seen at 6 h PI, where a few bacteria were found in close contact with the brush border. Conclusions The ligated intestinal loop model was useful with respect to maintaining an intact intestinal morphology for up to 6 h. Furthermore, the study demonstrated that L. intracellularis interacts with villus enterocytes within 3 to 6 h after inoculation into intestinal loops and that the bacterium, as shown for the vaccine bacteria, propagated as well as non-propagated, was able to invade mature enterocytes. Thus, the study demonstrates the early intestinal invasion of L. intracellularis in vivo.
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Early pathogenesis in porcine proliferative enteropathy caused by Lawsonia intracellularis. J Comp Pathol 2010; 143:101-9. [PMID: 20167332 DOI: 10.1016/j.jcpa.2010.01.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 09/10/2009] [Accepted: 01/05/2010] [Indexed: 11/20/2022]
Abstract
The intestinal bacterium Lawsonia intracellularis, the cause of proliferative enteropathy (PE) in pigs, is believed to infect mitotically active epithelial cells of the intestinal crypts and then multiply and spread in these cells as they divide. Further spread of infection is thought to occur by shedding of bacteria from infected crypts followed by infection of new crypts. The early stages of the pathogenesis of PE, from 0 to 48 hours post-infection (hpi), have not been studied in vivo. In the present study pigs were inoculated with L. intracellularis and killed from 12 hpi to 5 days post-infection (dpi). The localization of L. intracellularis was determined immunohistochemically and by fluorescence in-situ hybridization. At 12 hpi L. intracellularis was found within epithelial cells at the tips of villi, indicating infection of a range of epithelial cells including mature differentiated enterocytes. Furthermore, early invasion of the intestinal connective tissue was observed; with the presence of single bacteria in the lamina propria 12 hpi, and with a further spread of bacteria in the lamina propria observed at 5 dpi, suggesting an active role for the lamina propria in the course of infection.
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Microarray analysis of differential expression of cell cycle and cell differentiation genes in cells infected with Lawsonia intracellularis. Vet J 2009; 184:340-5. [PMID: 19362500 DOI: 10.1016/j.tvjl.2009.03.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 03/05/2009] [Accepted: 03/06/2009] [Indexed: 01/18/2023]
Abstract
Infection of intestinal crypt epithelial cells by the obligate intracellular bacterium Lawsonia intracellularis is directly linked to marked proliferation of the infected enterocytes within 3-5days post-infection. The virulence factor for this unique host cell-proliferative response is not known, but is considered to involve altered crypt cell cycle or differentiation events. McCoy mouse fibroblast cells were infected with L. intracellularis, and then harvested for expressed mRNA at daily time points, with matching non-infected control cell cultures. Mouse DNA microarray (>44,000 transcript targets) analysis of cDNA derived from matching mRNA samples showed over 40 identifiable genes with at least 4-fold changes between days 0 and 3 after infection with L. intracellularis. These included altered transcription of typical host cell 'alarm' response genes, such as interferon-related response genes Isgf3g and Igtp, known to be associated with invading microbial agents. Altered transcription of several genes in these cells known to be active in regulation of the cell cycle or cell differentiation genes, including usp18, Hr, Elavl2 and Slfn2, were also detected. The altered transcription of several of these genes via RT-PCR analysis was confirmed. The microarray-detected altered transcription of cell cycle and cell differentiation genes is of possible interest for links to Lawsonia-related disturbances in epithelial cell differentiation within the intestinal crypt, but this would need to be confirmed in intestinal epithelial cell studies.
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Brown EA, Kaushik RS, Hardwidge PR. Susceptibility of human enterotoxigenic Escherichia coli isolates to growth inhibition by porcine intestinal epithelial cells. FEMS Microbiol Lett 2007; 274:95-101. [PMID: 17590226 DOI: 10.1111/j.1574-6968.2007.00814.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Growth of human, but not porcine enterotoxigenic Escherichia coli (ETEC) isolates is inhibited during incubation with porcine intestinal epithelial cells and by a constitutively produced factor(s) present in unstimulated cell supernatants. The inhibitory factor(s) is heat stable, not produced by serum-starved cells, and is present in a diverse number of cultured epithelial cell lines of animal, but not of human origin. Susceptibility to porcine intestinal epithelial cells appears to be restricted to ETEC and not E. coli O157:H7 disease isolates.
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Affiliation(s)
- Eric A Brown
- Center for Infectious Disease Research and Vaccinology, South Dakota State University, Brookings, SD 57007, USA
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Kroll JJ, Roof MB, Hoffman LJ, Dickson JS, Harris DLH. Proliferative enteropathy: a global enteric disease of pigs caused byLawsonia intracellularis. Anim Health Res Rev 2007; 6:173-97. [PMID: 16583781 DOI: 10.1079/ahr2005109] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractProliferative enteropathy (PE; ileitis) is a common intestinal disease affecting susceptible pigs raised under various management systems around the world. Major developments in the understanding of PE and its causative agent,Lawsonia intracellularis, have occurred that have led to advances in the detection of this disease and methods to control and prevent it. Diagnostic tools that have improved overall detection and early onset of PE in pigs include various serological and molecular-based assays. Histological tests such as immunohistochemistry continue to be the gold standard in confirmingLawsonia-specific lesions in pigspost mortem. Despite extreme difficulties in isolatingL. intracellularis, innovations in the cultivation and the development of pure culture challenge models, have opened doors to better characterization of the pathogenesis of PE throughin vivoandin vitro L. intracellularis–host interactions. Advancements in molecular research such as the genetic sequencing of the entireLawsoniagenome have provided ways to identify various immunogens, metabolic pathways and methods for understanding the epidemiology of this organism. The determinations of immunological responsiveness in pigs to virulent and attenuated isolates ofL. intracellularisand identification of various immunogens have led to progress in vaccine development.
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Affiliation(s)
- Jeremy J Kroll
- Department of Research and Development, Boehringer Ingelheim Vetmedica Inc., 2501 North Loop Drive, Ames, Iowa 50010, USA.
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Brown DR, Price LD. Characterization of Salmonella enterica serovar Typhimurium DT104 invasion in an epithelial cell line (IPEC J2) from porcine small intestine. Vet Microbiol 2006; 120:328-33. [PMID: 17157450 PMCID: PMC1858663 DOI: 10.1016/j.vetmic.2006.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Revised: 10/27/2006] [Accepted: 11/02/2006] [Indexed: 10/23/2022]
Abstract
Salmonella Typhimurium DT104 is an emerging enteric pathogen in swine of increasing medical importance. In this study, the time course and the actin-dependent host signaling processes necessary for invasion of a S. Typhimurium DT104 field isolate were investigated in IPEC J2 epithelial cells derived from porcine small intestine. Internalized bacteria were quantified by a gentamicin resistance assay. DT104 internalization into epithelial monolayers increased steadily between 15 and 120min after apical inoculation. Internalization was reduced by the Rho GTPase inhibitor mevastatin, the N-WASP inhibitor wiskostatin and the actin-disrupting agent cytochalasin D, but not the Rac1 GTPase inhibitor NSC-23766. Early DT104 invasion of porcine enterocytes appears to be mediated by Rac1 GTPase-independent changes in epithelial actin assembly.
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Affiliation(s)
- David R Brown
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St Paul, MN 55108-6010, USA.
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Veldhuizen EJA, Hendriks HGCJM, Hogenkamp A, van Dijk A, Gaastra W, Tooten PCJ, Haagsman HP. Differential regulation of porcine beta-defensins 1 and 2 upon Salmonella infection in the intestinal epithelial cell line IPI-2I. Vet Immunol Immunopathol 2006; 114:94-102. [PMID: 16938353 DOI: 10.1016/j.vetimm.2006.07.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Revised: 07/12/2006] [Accepted: 07/25/2006] [Indexed: 12/22/2022]
Abstract
Intestinal epithelial cells represent the first line of defence against pathogenic bacteria in the lumen of the gut. Besides acting as a physical barrier, epithelial cells orchestrate the immune response through the production of several innate immune mediator molecules including beta-defensins. Here, we establish the porcine intestinal cell line IPI-2I as a new model system to test the regulation of porcine beta-defensins 1 and 2. Gene expression of both defensins was highly upregulated by foetal calf serum components in normal growth medium. In serum-free medium, baseline expression remained low, but pBD-2 gene expression was increased 10-fold upon infection with Salmonella Typhimurium. Arcobacter cryaerophilus and Salmonella Enteritidis, pathogenic bacteria with comparable adhesion and invasion characteristics, failed to increase pBD-2 mRNA levels. Heat killed or colistin-treated Salmonella Typhimurium had no effect, showing that the upregulation of pBD-2 was dependent on the viability of the Salmonella Typhimurium. Gene expression of pBD-1 was regulated differently since an increase in pBD-1 mRNA was observed by Salmonella Enteritidis infection. We conclude that the IPI-2I cells can serve as a new model to study porcine beta-defensin regulation and that pBD-1 and pBD-2 are differentially regulated in this cell line.
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Affiliation(s)
- Edwin J A Veldhuizen
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3508 TD Utrecht, The Netherlands.
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Abstract
In this study we examined the proliferative enteropathy, caused by the obligate intracellular bacterium Lawsonia intracellularis, in colon of naturally infected pigs, using immunohistochemistry, in situ hybridisation and scanning confocal laser microscopy. When 396 pigs submitted for routine laboratory examination were investigated, large intestinal gross lesions were seen in 93, including 74 cases of L. intracellularis colitis (proliferative enteropathy). Fifty-one pigs without recorded colonic gross lesions revealed L. intracellularis colitis microscopically. In four cases, L. intracellularis was only revealed in colon. Fifty-seven pigs were positive for L. intracellularis in the small intestines only. Thus, the overall prevalence of colonic infection in L. intracellularis-positive animals was as high as 69% (125 out of 182). In comparison, the large intestinal pathogens Brachyspira hyodysenteriae and Salmonella enterica were only isolated from 5 and 4 of the 93 cases, respectively. Morphologically, an unforeseen severe involvement of the subepithelial mucosa with multiple L. intracellularis found free and within large macrophages was observed in areas with acute infection. The distribution of whole L. intracellularis organisms was confirmed by in situ hybridisation and scanning confocal laser microscopy. The significance and possible role of subepithelial infection in the proliferative enteropathy is discussed. In conclusion, the study shows that L. intracellularis is a prevalent cause of naturally acquired colitis in pigs.
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Affiliation(s)
- T K Jensen
- Danish Veterinary Institute, Copenhagen, Denmark
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Schierack P, Nordhoff M, Pollmann M, Weyrauch KD, Amasheh S, Lodemann U, Jores J, Tachu B, Kleta S, Blikslager A, Tedin K, Wieler LH. Characterization of a porcine intestinal epithelial cell line for in vitro studies of microbial pathogenesis in swine. Histochem Cell Biol 2005; 125:293-305. [PMID: 16215741 DOI: 10.1007/s00418-005-0067-z] [Citation(s) in RCA: 294] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2005] [Indexed: 11/25/2022]
Abstract
In vitro studies on the pathogenesis in swine have been hampered by the lack of relevant porcine cell lines. Since many bacterial infections are swine-specific, studies on pathogenic mechanisms require appropriate cell lines of porcine origin. We have characterized the permanent porcine intestinal epithelial cell line, IPEC-J2, using a variety of methods in order to assess the usefulness of this cell line as an in vitro infection model. Electron microscopic analyses and histochemical staining revealed the cells to be enterocyte-like with microvilli, tight junctions and glycocalyx-bound mucin. The functional integrity of monolayers was determined by transepithelial electrical resistance (TEER) measurements. Both commensal bacteria and important bacterial pathogens were chosen for study based on their principally different infection mechanisms: obligate extracellular Escherichia coli, facultative intracellular Salmonella and obligate intracellular Chlamydia. We determined the colonization and proliferation of the bacteria on and within the host cells and monitored the host cell response. We verified the expression of mRNAs encoding the cytokines IL-1alpha, -6, -7, -8, -18, TNF-alpha and GM-CSF, but not TGF-beta or MCP-1. IL-8 protein expression was enhanced by Salmonella invasion. We conclude that the IPEC-J2 cell line provides a relevant in vitro model system for porcine intestinal pathogen-host cell interactions.
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Affiliation(s)
- Peter Schierack
- Institut für Mikrobiologie und Tierseuchen, Freie Universität Berlin, Berlin, Germany.
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Dittmar M, Hoelzle LE, Hoelzle K, Sydler T, Corboz L, Miserez R, Wittenbrink MM. Diagnosis of porcine proliferative enteropathy: detection of Lawsonia intracellularis by pathological examinations, polymerase chain reaction and cell culture inoculation. ACTA ACUST UNITED AC 2003; 50:332-8. [PMID: 14535931 DOI: 10.1046/j.1439-0450.2003.00691.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A total of 21 pigs aged 7-17 weeks with clinical symptoms suggestive for Porcine Proliferative Enteropathy were examined for Lawsonia intracellularis by analysing the following parameters: (i) intestinal gross and histological lesions, (ii) presence of comma-shaped bacteria in enterocytes by Warthin-Starry and a modified Ziehl-Neelsen stain, (iii) PCR amplification of L. intracellularis DNA from intestinal mucosa by using two oligonucleotide primer pairs targeting a 255-bp DNA fragment of the 16S rDNA-gene and a 319-bp DNA fragment of the L. intracellularis chromosome. Specificity of PCR reactions was confirmed by using DNA extracted from the L. intracellularis reference strain N343 (ATCC 55672) as well as by DNA sequence comparisons of PCR amplification products with data bank entries. Intestinal gross lesion indicative for PPE were observed in 20 pigs (95.2%). For all 21 pigs, the L. intracellularis aetiology was confirmed by histological as well as bacterioscopical examinations. Specific PCR amplification products were obtained from 20 pigs (95.2%). Taking PCR positivity as the definite criterion, L. intracellularis was diagnosed in 20 pigs from 11 herds in seven Swiss cantons (Argovia, Berne, Fribourg, Grisons, Lucerne, Schwyz, Thurgovia). To grow L. intracellularisin vitro, the cell culture method of Lawson et al. (J. Clin. Microbiol. 1993: 31, 1136-1142) was adopted. Inocula prepared from heavily infected fresh and frozen ileal mucosa of 15 pigs were cultured in rat enterocytic IEC-18 cells (ATCC CRL 1589). Six cell culture passages of 10 days each were completed. The reference strain N343 was examined for cultivability, accordingly. Except for occasional specific PCR amplifications from cell cultures up to the second passage, any indications for growth of L. intracellularis in IEC-18 cells were not found.
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Affiliation(s)
- M Dittmar
- Institute of Veterinary Bacteriology, University of Zurich, Winterthurerstrasse 270, CH-8057 Zurich, Switzerland
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MacIntyre N, Smith DGE, Shaw DJ, Thomson JR, Rhind SM. Immunopathogenesis of experimentally induced proliferative enteropathy in pigs. Vet Pathol 2003; 40:421-32. [PMID: 12824514 DOI: 10.1354/vp.40-4-421] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To characterize the immune response associated with Lawsonia intracellularis infection, twenty-eight, 7-week-old pigs were dosed orally with a pure culture of L. intracellularis. Animals were killed 3, 7, 14, 21, 28, 35, and 42 days postinfection. Light microscopic studies were undertaken to immunophenotype the immunologic response using specific antibodies to T-cell subsets (CD3, CD4, and CD8), B cells, major histocompatibility complex class II, cadherin, and macrophages over the course of time. The results indicate that there is a direct association between the presence of L. intracellularis and reduced T-cell and B-cell numbers. For the first time, this provides evidence of the presence of an immunosuppressive mechanism operating in this disease. Furthermore, macrophage marker studies indicated that macrophages may play a more complex and significant role in the disease process than has been previously reported, with activated macrophages accumulating in infected hyperplastic crypts.
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Affiliation(s)
- N MacIntyre
- Department of Veterinary Pathology, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush Veterinary Centre, Midlothian EH25 9RG, Scotland, UK
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Smith DG, Lawson GH. Lawsonia intracellularis: getting inside the pathogenesis of proliferative enteropathy. Vet Microbiol 2001; 82:331-45. [PMID: 11506927 DOI: 10.1016/s0378-1135(01)00397-2] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Although proliferative enteropathy (PE) has been recognised for several decades, Lawsonia intracellularis, the aetiological agent, was identified formally in only 1995. This organism is both highly fastidious and obligately intracellular bacterium, characteristics which have inevitably restricted investigations in all aspects of its biology. Despite these limitations, advances have been made in characterising and understanding L. intracellularis-host interaction both in vivo and in vitro. Based upon evidence provided by mainly pathological and histological investigations conducted to date, we review salient features of our current understanding of processes involved throughout the course of infection by this unique pathogen.
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Affiliation(s)
- D G Smith
- Zoonotic and Animal Pathogens Research Laboratory, Department of Medical Microbiology, University of Edinburgh, Teviot Place, Scotland EH8 9AG, Edinburgh, UK.
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Affiliation(s)
- G H Lawson
- Department of Veterinary Pathology, Edinburgh University Veterinary Field Station, Easter Bush, Roslin, Midlothian, EH25 9RG, UK
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McOrist S, Mackie RA, Lawson GH, Smith DG. In-vitro interactions of Lawsonia intracellularis with cultured enterocytes. Vet Microbiol 1997; 54:385-92. [PMID: 9100338 DOI: 10.1016/s0378-1135(96)01283-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Strains of the obligately intracellular bacterium Lawsonia intracellularis, the etiologic agent of porcine proliferative enteropathy, were co-cultured in rat enterocyte cell cultures (IEC-18) and examined ultrastructurally. No regular surface arrays typical of surface or S-layers were visible on any bacterial strain, with or without Triton-X-100 detergent treatment. In separate experiments, there was no difference in the ability of L. intracellularis to attach and enter enterocytes with or without the presence of added bovine plasma fibronectin, or the peptide Arg-Gly-Ser. Interestingly, there was an increase in the invasiveness of L. intracellularis in the presence of the peptide Arg-Gly-Asp (RGD), in a dose-related manner. A reduction was observed in the ability of L. intracellularis to invade enterocytes in the presence of monovalent fragments of IgG monoclonal antibodies to an outer surface component of L. intracellularis. This neutralization showed an antibody concentration-dependent titration effect and was not apparent with co-cultures incorporating control antibodies. The exact nature of ligand and cell receptor interactions for L. intracellularis remain to be determined.
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Affiliation(s)
- S McOrist
- Department of Veterinary Pathology, University of Edinburgh, Easter Bush, Midlothian, UK
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Smith SH, McOrist S. Development of persistent intestinal infection and excretion of Lawsonia intracellularis by piglets. Res Vet Sci 1997; 62:6-10. [PMID: 9160416 DOI: 10.1016/s0034-5288(97)90171-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Challenge experiments using Lawsonia intracellularis as oral inocula have established its aetiological role in porcine proliferative enteropathy. Thirty piglets, in four groups, were weaned at 21 days of age and inoculated orally at 24 days. Six piglets were challenged with 1.0 x 10(8) L intracellularis strain 916/91 (NCTC 12657) passaged 12 times in vitro, six with 5.0 x 10(8) of the same strain, seven with 3.0 x 10(8) L intracellularis strain LR 189/5/83, passaged nine times, and 11 controls were dosed with sucrose-potassium glutamate buffer. An immunofluorescence assay for L intracellularis was applied to faecal smears and a polymerase chain reaction (PCR) incorporating L intracellularis-specific primers was applied to extracts of bacterial DNA derived from the faeces samples. Up to five pigs in each challenge group excreted detectable L intracellularis in faeces, in samples taken between two and 10 weeks after challenge. Some of the pigs had up to 7 x 10(8) L intracellularis g-1 faeces. The average weight gains of the higher dose challenge groups were moderately below those of the control pigs between three and nine weeks after challenge; diarrhoea was also observed in six pigs, two to four weeks after challenge. Numerous L intracellularis were detected in the intestines of all the pigs challenged with strain LR 189/5/83 and two of the pigs challenged with 916/91, but not in other tissues.
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Affiliation(s)
- S H Smith
- Department of Veterinary Pathology, University of Edinburgh
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McOrist S, Roberts L, Jasni S, Rowland AC, Lawson GH, Gebhart CJ, Bosworth B. Developed and resolving lesions in porcine proliferative enteropathy: possible pathogenetic mechanisms. J Comp Pathol 1996; 115:35-45. [PMID: 8878750 DOI: 10.1016/s0021-9975(96)80026-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Proliferative enteropathy, caused by Lawsonia intracellularis, offers the opportunity to examine bacterial mechanisms that influence epithelial cell proliferation. Ultrastructural features of developed and resolving lesions included the presence of enlarged intestinal crypts containing undifferentiated immature epithelial cells and an absence of goblet cells. Numerous intracytoplasmic bacteria, identified as L. intracellularis, were consistently present within affected cells. In recovering intestinal tissue, additional features were (1) the common presence of pale, swollen, protruding epithelial cells, (2) shrunken, degenerate epithelial cells, (3) apoptotic bodies in both epithelial cells and macrophages, (4) the reappearance of normal goblet cells, and (5) reduced numbers of L. intracellularis within lesions. Bacteria were released from cells via cytoplasmic and cellular protrusions into the intestinal lumen. It is speculated that the presence of the intracytoplasmic bacterium, L. intracellularis, may disrupt normal processes of cell growth, differentiation or apoptosis in the intestinal epithelium.
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Affiliation(s)
- S McOrist
- Department of Veterinary Pathology, University of Edinburgh, Scotland
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Lawson GH, Mackie RA, Smith DG, McOrist S. Infection of cultured rat enterocytes by Ileal symbiont intracellularis depends on host cell function and actin polymerisation. Vet Microbiol 1995; 45:339-50. [PMID: 7483247 DOI: 10.1016/0378-1135(94)00142-j] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The mechanisms of entry of Ileal symbiont intracellularis into IEC-18 rat enterocyte cells and subsequent bacterial proliferation were examined in centrifuge-assisted and static infections. Live, oxygen or neomycin damaged, and formalin killed bacteria, each rapidly entered viable cells. Live or damaged bacteria did not enter cells nor proliferate within cells after static infection of cells cooled to 5 degrees C. Infection of cells was greatly reduced at 20 degrees or 32 degrees compared to infection at 37 degrees C. Centrifuge-assisted infection was also reduced by chilling the cells. Cytochalasin D but not B inhibited the entry process indicating an actin-dependent infection, although other pathways may also be involved in centrifuge-assisted infections. Drugs capable of modifying cell membrane charge, heparin receptors or trypsin-labile proteins were all inactive in preventing or enhancing infection. We therefore conclude that infection of enterocytes by IS intracellularis is dependent on host cell activity and actin polymerization, but is independent of bacterial viability.
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Affiliation(s)
- G H Lawson
- Department of Veterinary Pathology, University of Edinburgh, Easter Bush, Midlothian, UK
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