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Zhang L, Toboso-Navasa A, Gunawan A, Camara A, Nakagawa R, Katja F, Chakravarty P, Newman R, Zhang Y, Eilers M, Wack A, Tolar P, Toellner KM, Calado DP. Regulation of BCR-mediated Ca 2+ mobilization by MIZ1- TMBIM4 safeguards IgG1 + GC B cell-positive selection. Sci Immunol 2024; 9:eadk0092. [PMID: 38579014 PMCID: PMC7615907 DOI: 10.1126/sciimmunol.adk0092] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 02/26/2024] [Indexed: 04/07/2024]
Abstract
The transition from immunoglobulin M (IgM) to affinity-matured IgG antibodies is vital for effective humoral immunity. This is facilitated by germinal centers (GCs) through affinity maturation and preferential maintenance of IgG+ B cells over IgM+ B cells. However, it is not known whether the positive selection of the different Ig isotypes within GCs is dependent on specific transcriptional mechanisms. Here, we explored IgG1+ GC B cell transcription factor dependency using a CRISPR-Cas9 screen and conditional mouse genetics. We found that MIZ1 was specifically required for IgG1+ GC B cell survival during positive selection, whereas IgM+ GC B cells were largely independent. Mechanistically, MIZ1 induced TMBIM4, an ancestral anti-apoptotic protein that regulated inositol trisphosphate receptor (IP3R)-mediated calcium (Ca2+) mobilization downstream of B cell receptor (BCR) signaling in IgG1+ B cells. The MIZ1-TMBIM4 axis prevented mitochondrial dysfunction-induced IgG1+ GC cell death caused by excessive Ca2+ accumulation. This study uncovers a unique Ig isotype-specific dependency on a hitherto unidentified mechanism in GC-positive selection.
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Affiliation(s)
- Lingling Zhang
- Immunity and Cancer, Francis Crick Institute, London, UK
| | | | - Arief Gunawan
- Immunity and Cancer, Francis Crick Institute, London, UK
| | | | | | | | | | - Rebecca Newman
- Immune Receptor Activation Laboratory, Francis Crick Institute, London, UK
| | - Yang Zhang
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK
| | - Martin Eilers
- Theodor Boveri Institute and Comprehensive Cancer Center Mainfranken, Biocenter, University of Würzburg, Würzburg, Germany
| | | | - Pavel Tolar
- Immune Receptor Activation Laboratory, Francis Crick Institute, London, UK
- Division of Infection and Immunity, Institute of Immunity and Transplantation, University College London, London, UK
| | - Kai-Michael Toellner
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK
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Hu Z, He L, Wei J, Su Y, Wang W, Fan Z, Xu J, Zhang Y, Wang Y, Peng M, Zhao K, Zhang H, Liu C. tmbim4 protects against triclocarban-induced embryonic toxicity in zebrafish by regulating autophagy and apoptosis. Environ Pollut 2021; 277:116873. [PMID: 33714789 DOI: 10.1016/j.envpol.2021.116873] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 02/04/2021] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Triclocarban (TCC), an antibacterial agent widely used in personal care products, can affect embryonic development. However, the specific molecular mechanism of TCC-induced embryonic developmental damage remains unclear. In this study, TCC exposure was found to increase the expression of tmbim4 gene in zebrafish embryos. The tmbim4 mutant embryos are more susceptible to TCC exposure than wild-type (WT) embryos, with tmbim4 overexpression reducing TCC-induced embryonic death in the former. Exposure of tmbim4 mutant larvae to 400 μg/L TCC substantially increased apoptosis in the hindbrain and eyes. RNA-sequencing of WT and tmbim4 mutant larvae indicated that knockout of the tmbim4 gene in zebrafish affects the autophagy pathway. Abnormalities in autophagy can increase apoptosis and TCC exposure caused abnormal accumulation of autophagosomes in the hindbrain of tmbim4 mutant zebrafish embryos. Pretreatment of TCC-exposed tmbim4 mutant zebrafish embryos with autophagosome formation inhibitors, substantially reduced the mortality of embryos and apoptosis levels. These results indicate that defects in the tmbim4 gene can reduce zebrafish embryo resistance to TCC. Additionally, apoptosis induced by abnormal accumulation of autophagosomes is involved in this process.
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Affiliation(s)
- Zhiyong Hu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China
| | - Liting He
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China
| | - Jiajing Wei
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China
| | - Yufang Su
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China
| | - Wei Wang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China
| | - Zunpan Fan
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China
| | - Jia Xu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China
| | - Yuan Zhang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China
| | - Yongfeng Wang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China
| | - Meilin Peng
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China
| | - Kai Zhao
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China
| | - Huiping Zhang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China
| | - Chunyan Liu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, PR China.
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