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Pereira CER, Resende TP, Daniel AGDS, Vannucci FA, Gebhart C, Guedes RMC. Evaluation of the role of clathrin and bacterial viability in the endocytosis of Lawsonia intracellularis. Front Vet Sci 2023; 10:1005676. [PMID: 36793380 PMCID: PMC9923121 DOI: 10.3389/fvets.2023.1005676] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 01/10/2023] [Indexed: 01/31/2023] Open
Abstract
Lawsonia intracellularis is an obligate intracellular bacterium and causative agent of proliferative enteropathy. The pathogenesis of L. intracellularis is not completely understood, including the endocytic mechanisms to access the host cell cytoplasm. In this study, we evaluated the mechanisms involved in endocytosis of L. intracellularis in vitro using intestinal porcine epithelial cells (IPEC-J2). Confocal microscopy was used to co-localize L. intracellularis and clathrin. Clathrin gene knockdown was then applied to verify whether L. intracellularis endocytosis is clathrin-dependent. Finally, internalization of viable and non-viable (bacteria were inactivated by heat) L. intracellularis organisms were assessed to study the role of the host cell during bacterial endocytosis. L. intracellularis organisms were observed co-localized with clathrin by confocal microscopy but the amount of L. intracellularis internalized in cells, with and without clathrin knockdown, did not differ statistically. The internalization of non-viable L. intracellularis showed a decrease in the internalization in cells with less clathrin synthesis (P<0.05). The present study is the first to elucidate the involvement of clathrin in the endocytosis of L. intracellularis. Clathrin-mediated endocytosis was shown to be an important, but not required, process for L. intracellularis internalization in porcine intestinal epithelial cells. Independence of bacterial viability for host cell internalization was also confirmed.
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Affiliation(s)
- Carlos Eduardo Real Pereira
- Department of Clinic and Surgery, Escola de Veterinária, 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, MN, United States
| | - Talita Pilar Resende
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Amanda Gabrielle de Souza Daniel
- Department of Clinic and Surgery, Escola de Veterinária, 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, MN, United States
| | - Fabio Augusto Vannucci
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Connie Gebhart
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Roberto Mauricio Carvalho Guedes
- Department of Clinic and Surgery, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil,*Correspondence: Roberto Mauricio Carvalho Guedes ✉
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Pereira CER, Araújo MSS, da Silva Mol JP, Sato JPH, de Souza Daniel AG, Martins-Filho OA, Santos RL, Guedes RMC. Phenotypic characterization of swine peripheral blood monocyte-derived macrophages and ex vivo infection with Salmonella enterica serovar Typhimurium. Braz J Microbiol 2019; 50:539-546. [PMID: 30680603 DOI: 10.1007/s42770-019-00042-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 11/19/2018] [Indexed: 11/27/2022] Open
Abstract
Macrophages are critical mediators of the inflammatory process, playing a relevant role in the pathogenesis of Salmonella Typhimurium. The protocols for isolation, culture, and differentiation of monocytes into macrophages and their interaction with Salmonella are well established in humans and murine models, but little information is available in swine. The aims of this study were to establish an efficient protocol for macrophage culture and to evaluate the interaction of the invA mutant strain and the wild type (WT) Salmonella Typhimurium with porcine macrophages. Peripheral blood monocyte-derived macrophages from pigs were obtained, separated by density-gradient centrifugation, and cultured in Teflon vials for 10 days. After the differentiation period, cultures consisted of 92.4% CD14+ cells. In addition, these cells showed phagocytic ability, demonstrated by the presence of the same amount of WT and invA mutant Salmonella Typhimurium 1 h after interaction with macrophages. The early cytotoxic effect was Salmonella pathogenicity island (SPI)-[1]dependent, in which log-phase WT strains were more efficient (p < 0.01) than the invA mutant strain at inducing the death of macrophages.
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Affiliation(s)
- Carlos Eduardo Real Pereira
- Departmento de Clínica e Cirúrgia Veterinária, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, MG, 31270-901, Brazil
| | - Márcio Sobreira Silva Araújo
- Laboratório de Biomarcadores de Diagnóstico e Monitoração, Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brazil
| | - Juliana Pinto da Silva Mol
- Departmento de Clínica e Cirúrgia Veterinária, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, MG, 31270-901, Brazil
| | - José Paulo Hiroji Sato
- Departmento de Clínica e Cirúrgia Veterinária, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, MG, 31270-901, Brazil
| | - Amanda Gabrielle de Souza Daniel
- Departmento de Clínica e Cirúrgia Veterinária, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, MG, 31270-901, Brazil
| | - Olindo Assis Martins-Filho
- Laboratório de Biomarcadores de Diagnóstico e Monitoração, Centro de Pesquisas René Rachou-Fiocruz, Belo Horizonte, MG, Brazil
| | - Renato Lima Santos
- Departmento de Clínica e Cirúrgia Veterinária, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, MG, 31270-901, Brazil
| | - Roberto Mauricio Carvalho Guedes
- Departmento de Clínica e Cirúrgia Veterinária, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, MG, 31270-901, Brazil.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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