Inactivation of glutathione S-transferase alpha 4 blocks Enterococcus faecalis-induced bystander effect by promoting macrophage ferroptosis
Enterococcus faecalis-infected macrophages produce 4-hydroxynonenal (4-HNE) that mediates microbiota-induced bystander effect (MIBE) leading to colorectal cancer (CRC). Glutathione S-transferase alpha 4 (Gsta4), a specific detoxifying enzyme for 4-HNE, is overexpressed in human CRC and E. faecalis-i...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Taylor & Francis Group
2025-12-01
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| Series: | Gut Microbes |
| Subjects: | |
| Online Access: | https://www.tandfonline.com/doi/10.1080/19490976.2025.2451090 |
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| Summary: | Enterococcus faecalis-infected macrophages produce 4-hydroxynonenal (4-HNE) that mediates microbiota-induced bystander effect (MIBE) leading to colorectal cancer (CRC). Glutathione S-transferase alpha 4 (Gsta4), a specific detoxifying enzyme for 4-HNE, is overexpressed in human CRC and E. faecalis-induced murine CRC. However, the roles of Gsta4 in E. faecalis-induced colitis and CRC remain unclear. Herein, we demonstrate that Gsta4 is essential for MIBE by protecting macrophages from E. faecalis-induced ferroptosis. E. faecalis OG1RFSS was used to induce colitis in Gsta4−/− and Il10−/−/Gsta4−/− mice by orogastric gavage. Ferroptosis was assessed in Gsta4-deficient murine macrophages. We found that, unlike Il10−/− mice, Gsta4−/− and Il10−/−/Gsta4−/− mice colonized with E. faecalis failed to develop colitis or CRC. Immunofluorescent staining showed a reduction of macrophages in the lamina propria of E. faecalis-colonized Il10−/−/Gsta4−/− mice, as well as decreased Gpx4 expression, indicating the occurrence of ferroptosis. Ferroptosis was further confirmed in Gsta4-deficient murine macrophages infected with E. faecalis. Moreover, Gsta4 inactivation induced the upregulation of Hmox1 and phosphorylated c-Jun while blocked Nos2 expression, leading to the accumulation of intracellular ferrous iron, lipid peroxidation and, eventually, ferroptosis. Finally, Mapk8, as a ferroptosis driver, was remarkably elevated in E. faecalis-infected Gsta4-deficient macrophages. These results suggest that Gsta4 inactivation blocks MIBE by eliminating macrophages, thereby attenuates E. faecalis-induced colitis and CRC. |
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| ISSN: | 1949-0976 1949-0984 |