Abstract
Enzymes of the TET family are methylcytosine dioxygenases that undergo frequent mutational or functional inactivation in human cancers. Recurrent loss-of-function mutations in TET proteins are frequent in human diffuse large B cell lymphoma (DLBCL). Here, we investigate the role of TET proteins in B cell homeostasis and development of B cell lymphomas with features of DLBCL. We show that deletion of Tet2 and Tet3 genes in mature B cells in mice perturbs B cell homeostasis and results in spontaneous development of germinal center (GC)-derived B cell lymphomas with increased G-quadruplexes and R-loops. At a genome-wide level, G-quadruplexes and R-loops were associated with increased DNA double-strand breaks (DSBs) at immunoglobulin switch regions. Deletion of the DNA methyltransferase DNMT1 in TET-deficient B cells prevented expansion of GC B cells, diminished the accumulation of G-quadruplexes and R-loops and delayed B lymphoma development, consistent with the opposing functions of DNMT and TET enzymes in DNA methylation and demethylation. Clustered regularly interspaced short palindromic repeats (CRISPR)-mediated depletion of nucleases and helicases that regulate G-quadruplexes and R-loops decreased the viability of TET-deficient B cells. Our studies suggest a molecular mechanism by which TET loss of function might predispose to the development of B cell malignancies.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 99-108 |
| Number of pages | 10 |
| Journal | Nature Immunology |
| Volume | 23 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2022 |
Funding
We thank H. Yuita and I. Lopez-Moyado for generating the ERT2-cre Tet1fl/fl Tet2fl/fl Tet3fl/fl, ERT2-cre TKO mice, D. Kitamura at the Tokyo University of Science for sharing the 40LB cells, U. Basu and B. Laffleur at Columbia University for help with the HTGTS protocol, our collaborators at Cambridge Epigenetix (UK) for providing the 5hmC mapping kits, the LJI Flow Cytometry Core team (C. Kim, D. Hinz, C. Dillingham, M Haynes and S. Ellis) for help with cell sorting and the LJI next-generation sequencing core members (J. Day, S. Alarcon, H. Dose, K. Tanaguay and A. Hernandez) for help with sequencing. The BD FACSAria II is supported by the NIH (NIH S10OD016262, NIH S10RR027366), and our research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract number DE-AC02-05CH11231. The NovaSeq 6000 and the HiSeq 2500 were acquired through the Shared Instrumentation Grant (SIG) Program (S10) (NovaSeq 6000 S10OD025052 and HiSeq 2500 S10OD016262). K.S. acknowledges support from NIH grant DP2-NS105576. V.S. was supported by a Leukemia and Lymphoma Society Postdoctoral Fellowship (grant ID 5463-18) and currently by a K99/ R00 award from the National Cancer Institute (grant ID CA248835). D.S.-C. and E.G.-A. were supported by University of California Institute for Mexico and the United States and El Consejo Nacional de Ciencia y Tecnología (UCMEXUS/CONACYT) pre-doctoral fellowship. This work is supported by the NIH grants R35 CA210043, R01 AI109842 and AI128589 to A.R. and K99/R00 CA248835, research funds from LLS grant 5463-18 and the Tullie and Rickey families SPARK award from LJI to V.S.
ASJC Scopus subject areas
- Immunology and Allergy
- Immunology
