Early Intracellular Trafficking and Subsequent Activity of Programmed Cell Death in Channel Catfish Macrophages Infected with <i>Edwardsiella ictaluri</i>
The development of <i>Edwardsiella</i>-containing-vacuoles (ECV) and the ability of <i>Edwardsiella ictaluri</i> to survive and replicate within macrophages suggests a unique process relative to normal phagosomal/lysosomal maturation and programed cell death. Developing ECV s...
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MDPI AG
2020-10-01
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| Series: | Microorganisms |
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| Online Access: | https://www.mdpi.com/2076-2607/8/11/1649 |
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| author | Lidiya P. Dubytska Ronald L. Thune |
| author_facet | Lidiya P. Dubytska Ronald L. Thune |
| author_sort | Lidiya P. Dubytska |
| collection | DOAJ |
| description | The development of <i>Edwardsiella</i>-containing-vacuoles (ECV) and the ability of <i>Edwardsiella ictaluri</i> to survive and replicate within macrophages suggests a unique process relative to normal phagosomal/lysosomal maturation and programed cell death. Developing ECV showed that endosomal membrane markers Rab5, EEA1, and Rab7 were all detected in both the wild type (WT) and an <i>E. ictaluri</i> type-3 secretion system (T3SS) mutant, 65ST. Co-localization with Lamp1, however, was significantly lower in the WT. The host cell endoplasmic reticulum marker, calnexin, co-localized to 65ST ECV significantly more than WT ECV, while Golgi vesicle marker, giantin, was recruited to WT ECV significantly more than 65ST. The autophagosomal marker LC3 was significantly lower in WT than in 65ST and Western blotting demonstrated significantly greater induction of the membrane localized, lipidated form, LC3-II, in 65ST ECV than in WT ECV. Activity of the apoptosis initiator caspase-8 increased post-infection in 65ST and was significantly lower in WT-infected cells. Executioner caspase-3/7 activity also increased significantly in 65ST-infected cells compared to WT-infected cells. Repression of apoptosis was further demonstrated with flow cytometry using Alexa Fluor 647-labeled Annexin V and propidium iodide. Results indicate that WT ECV fused with early and late endosomes but that phagosomal/lysosomal fusion did not occur. Additionally, WT-infected cells recruited Golgi vesicles for vacuolar size increase and bacterial growth material, and both autophagy and apoptosis were repressed in the WT. This activity was all based on the function of the <i>E. ictaluri</i> T3SS. |
| first_indexed | 2024-03-10T15:21:34Z |
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| language | English |
| last_indexed | 2024-03-10T15:21:34Z |
| publishDate | 2020-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Microorganisms |
| spelling | doaj.art-46538c9933a64ef680be2efc79ac2d332023-11-20T18:24:16ZengMDPI AGMicroorganisms2076-26072020-10-01811164910.3390/microorganisms8111649Early Intracellular Trafficking and Subsequent Activity of Programmed Cell Death in Channel Catfish Macrophages Infected with <i>Edwardsiella ictaluri</i>Lidiya P. Dubytska0Ronald L. Thune1Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, LA 70803, USADepartment of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, LA 70803, USAThe development of <i>Edwardsiella</i>-containing-vacuoles (ECV) and the ability of <i>Edwardsiella ictaluri</i> to survive and replicate within macrophages suggests a unique process relative to normal phagosomal/lysosomal maturation and programed cell death. Developing ECV showed that endosomal membrane markers Rab5, EEA1, and Rab7 were all detected in both the wild type (WT) and an <i>E. ictaluri</i> type-3 secretion system (T3SS) mutant, 65ST. Co-localization with Lamp1, however, was significantly lower in the WT. The host cell endoplasmic reticulum marker, calnexin, co-localized to 65ST ECV significantly more than WT ECV, while Golgi vesicle marker, giantin, was recruited to WT ECV significantly more than 65ST. The autophagosomal marker LC3 was significantly lower in WT than in 65ST and Western blotting demonstrated significantly greater induction of the membrane localized, lipidated form, LC3-II, in 65ST ECV than in WT ECV. Activity of the apoptosis initiator caspase-8 increased post-infection in 65ST and was significantly lower in WT-infected cells. Executioner caspase-3/7 activity also increased significantly in 65ST-infected cells compared to WT-infected cells. Repression of apoptosis was further demonstrated with flow cytometry using Alexa Fluor 647-labeled Annexin V and propidium iodide. Results indicate that WT ECV fused with early and late endosomes but that phagosomal/lysosomal fusion did not occur. Additionally, WT-infected cells recruited Golgi vesicles for vacuolar size increase and bacterial growth material, and both autophagy and apoptosis were repressed in the WT. This activity was all based on the function of the <i>E. ictaluri</i> T3SS.https://www.mdpi.com/2076-2607/8/11/1649<i>Edwardsiella ictaluri</i>type-3 secretion systemEdwardsiella-containing-vacuolesautophagyapoptosis |
| spellingShingle | Lidiya P. Dubytska Ronald L. Thune Early Intracellular Trafficking and Subsequent Activity of Programmed Cell Death in Channel Catfish Macrophages Infected with <i>Edwardsiella ictaluri</i> Microorganisms <i>Edwardsiella ictaluri</i> type-3 secretion system Edwardsiella-containing-vacuoles autophagy apoptosis |
| title | Early Intracellular Trafficking and Subsequent Activity of Programmed Cell Death in Channel Catfish Macrophages Infected with <i>Edwardsiella ictaluri</i> |
| title_full | Early Intracellular Trafficking and Subsequent Activity of Programmed Cell Death in Channel Catfish Macrophages Infected with <i>Edwardsiella ictaluri</i> |
| title_fullStr | Early Intracellular Trafficking and Subsequent Activity of Programmed Cell Death in Channel Catfish Macrophages Infected with <i>Edwardsiella ictaluri</i> |
| title_full_unstemmed | Early Intracellular Trafficking and Subsequent Activity of Programmed Cell Death in Channel Catfish Macrophages Infected with <i>Edwardsiella ictaluri</i> |
| title_short | Early Intracellular Trafficking and Subsequent Activity of Programmed Cell Death in Channel Catfish Macrophages Infected with <i>Edwardsiella ictaluri</i> |
| title_sort | early intracellular trafficking and subsequent activity of programmed cell death in channel catfish macrophages infected with i edwardsiella ictaluri i |
| topic | <i>Edwardsiella ictaluri</i> type-3 secretion system Edwardsiella-containing-vacuoles autophagy apoptosis |
| url | https://www.mdpi.com/2076-2607/8/11/1649 |
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