MicroRNA-155 controls affinity-based selection by protecting c-MYC+ B cells from apoptosis.
Phan, Tri Giang
Journal of Clinical Investigation
American Society for Clinical Investigation
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Nakagawa, R., Leyland, R., Meyer-Hermann, M., Lu, D., Turner, M., Arbore, G., Phan, T. G., et al. (2016). MicroRNA-155 controls affinity-based selection by protecting c-MYC+ B cells from apoptosis.. Journal of Clinical Investigation, 126 (1), 377-388. https://doi.org/10.1172/JCI82914
The production of high-affinity antibodies by B cells is essential for pathogen clearance. Antibody affinity for antigen is increased through the affinity maturation in germinal centers (GCs). This is an iterative process in which B cells cycle between proliferation coupled with the acquisition of mutations and antigen-based positive selection, resulting in retention of the highest-affinity B cell clones. The posttranscriptional regulator microRNA-155 (miR-155) is critical for efficient affinity maturation and the maintenance of the GCs; however, the cellular and molecular mechanism by which miR-155 regulates GC responses is not well understood. Here, we utilized a miR-155 reporter mouse strain and showed that miR-155 is coexpressed with the proto-oncogene encoding c-MYC in positively selected B cells. Functionally, miR-155 protected positively selected c-MYC+ B cells from apoptosis, allowing clonal expansion of this population, providing an explanation as to why Mir155 deletion impairs affinity maturation and promotes the premature collapse of GCs. We determined that miR-155 directly inhibits the Jumonji family member JARID2, which enhances B cell apoptosis when overexpressed, and thereby promotes GC B cell survival. Our findings also suggest that there is cooperation between c-MYC and miR-155 during the normal GC response, a cooperation that may explain how c-MYC and miR-155 can collaboratively function as oncogenes.
Animals, Apoptosis, B-Lymphocytes, Cell Survival, Germinal Center, Mice, Mice, Inbred C57BL, MicroRNAs, Polycomb Repressive Complex 2, Proto-Oncogene Proteins c-myc
R. Nakagawa was supported by a Marie Curie Incoming Fellowship from the European Union’s Seventh Framework Programme for research, technological development, and demonstration. E. Vigorito was supported by the Medical Research Council grants G1001781 and G0700287 and by the Biotechnology and Biological Sciences Research Council. M. Meyer-Hermann was supported by the German Federal Ministry of Education and Research within the Measures for the Establishment of Systems Medicine, project SYSIMIT (BMBF eMed project SYSIMIT, FKZ: 01ZX1308B) and by the Human Frontier Science Program (RGP0033/2015).
External DOI: https://doi.org/10.1172/JCI82914
This record's URL: https://www.repository.cam.ac.uk/handle/1810/293107