1/ New insights into control of #tregs by #DNAmethylation from #SingerLab. #epigenetics @luisamnMD @NMPulmCritCare
Check out our new preprint on @biorxivpreprint: biorxiv.org/cgi/content/sh…
Check out our new preprint on @biorxivpreprint: biorxiv.org/cgi/content/sh…
2/ Treg cells are known to require a lineage-specific DNA hypomethylation pattern during development that stabilizes their lineage. We wanted to determine whether maintenance DNA methylation is required for Treg cell lineage development and stability.
3/ Accordingly, we bred mice with Treg cell-specific deficiency in the epigenetic regulator Uhrf1, which maintains methyl-DNA marks. These mice displayed a profound inflammatory phenotype.
4/ Treg cells were dramatically reduced in mice that lacked Uhrf1 in their Treg cells.
5/ We then generated Uhrf1 chimeric knockout mice and found that deficiency of Uhrf1 in Treg cells results in loss of the Treg cell lineage-defining transcriptional signature, disruption of DNA methylation patterning, and derepression of effector programs.
6/ Next, we selectively deleted Uhrf1 in the Treg cells of adult mice to determine the necessity of Uhrf1 in lineage stability. These mice also became ill from systemic inflammation.
7/ In addition, these mice exhibited increased generation of ex-Foxp3 cells, indicating destabilization of the Treg cell lineage.
8/ RNA-seq of the sorted cell populations revealed that ex-Foxp3 cells generated following loss of Uhrf1 display an excessively activated and inflammatory phenotype.
9/ DNA methylation profiling with genome-wide bisulfite sequencing demonstrated differentially methylated regions that explained the transcriptional reprogramming observed in Uhrf1-deficient ex-Foxp3 cells.
10/ Finally, we tested the functional implications of induced deletion of Uhrf1 in mature Treg cells by examining the effect on melanoma growth in vivo. Loss of Uhrf1 was sufficient to slow tumor growth and increase the frequency of intra-tumoral ex-Foxp3 cells.
11/ Collectively, our results demonstrate that Foxp3+ Treg cells require Uhrf1-mediated maintenance of DNA methylation at inflammatory gene loci for their development and functional stability.
12/ Our findings change the existing model of DNA hypomethylation as the dominant feature of the Treg cell epigenome by demonstrating an essential role for methylation-mediated silencing of effector programs in the development and stability of the Treg cell lineage.
Many thanks to Katie Helmin and all the co-authors for their tremendous work on this project!
