Inactivation of glutathione S-transferase alpha 4 blocks Enterococcus faecalis-induced bystander effect by promoting macrophage ferroptosis
Yuanyuan Ju,
Chunhua Ma,
Lin Huang,
Yumei Tao,
Tianqi Li,
Haibo Li,
Mark M. Huycke,
Yonghong Yang,
Xingmin Wang
Affiliations
Yuanyuan Ju
Nantong Institute of Genetics and Reproductive Medicine, Affiliated Maternity and Child Healthcare Hospital of Nantong University, Nantong, Jiangsu, China
Chunhua Ma
Nantong Institute of Genetics and Reproductive Medicine, Affiliated Maternity and Child Healthcare Hospital of Nantong University, Nantong, Jiangsu, China
Lin Huang
Department of Gastroenterology, Affiliated Maternity and Child Healthcare Hospital of Nantong University, Nantong, Jiangsu, China
Yumei Tao
Department of Pathology, Affiliated Maternity and Child Healthcare Hospital of Nantong University, Nantong, Jiangsu, China
Tianqi Li
Nantong Institute of Genetics and Reproductive Medicine, Affiliated Maternity and Child Healthcare Hospital of Nantong University, Nantong, Jiangsu, China
Haibo Li
Department of Clinical Laboratory, Affiliated Maternity and Child Healthcare Hospital of Nantong University, Nantong, Jiangsu, China
Mark M. Huycke
Stephenson Cancer Center, Department of Radiation Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
Yonghong Yang
Department of Nephrology, Rheumatology, and Immunology, Nantong Children’s Hospital, Nantong, Jiangsu, China
Xingmin Wang
Nantong Institute of Genetics and Reproductive Medicine, Affiliated Maternity and Child Healthcare Hospital of Nantong University, Nantong, Jiangsu, China
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.
