Dataset Information

BET Bromodomain Inhibitors Which Permit Treg Function Enable a Combinatorial Strategy to Suppress GVHD in Pre-clinical Allogeneic HSCT.

ABSTRACT: A recent approach for limiting production of pro-inflammatory cytokines has been to target bromodomain and extra-terminal (BET) proteins. These epigenetic readers of histone acetylation regulate transcription of genes involved in inflammation, cardiovascular disease, and cancer. Development of BET inhibitors (BETi) has generated enormous interest for their therapeutic potential. Because inflammatory signals and donor T cells promote graft-versus-host disease (GVHD), regulating both pathways could be effective to abrogate this disorder. The objective of the present study was to identify a BETi which did not interfere in vivo with CD4+FoxP3+ regulatory T cell (Treg) expansion and function to utilize together with Tregs following allogeneic hematopoietic stem cell transplantation (aHSCT) to ameliorate GVHD. We have reported that Tregs can be markedly expanded and selectively activated with increased functional capacity by targeting TNFRSF25 and CD25 with TL1A-Ig and low dose IL-2, respectively. Here, mice were treated over 7 days (TL1A-Ig + IL-2) together with BETi. We found that the BETi EP11313 did not decrease frequency/numbers or phenotype of expanded Tregs as well as effector molecules, such as IL-10 and TGF-?. However, BETi JQ1 interfered with Treg expansion and altered subset distribution and phenotype. Notably, in Treg expanded mice, EP11313 diminished tnfa and ifng but not il-2 RNA levels. Remarkably, Treg pSTAT5 expression was not affected by EP11313 supporting the notion that Treg IL-2 signaling remained intact. MHC-mismatched aHSCT (B6 ? BALB/c) was performed using in vivo expanded donor Tregs with or without EP11313 short-term treatment in the recipient. Early post-transplant, improvement in the splenic and LN CD4/CD8 ratio along with fewer effector cells and high Treg levels in aHSCT recipients treated with expanded Tregs + EP11313 was detected. Interestingly, this group exhibited a significant diminution of GVHD clinical score with less skin and ocular involvement. Finally, using low numbers of highly purified expanded Tregs, improved clinical GVHD scores were observed in EP11313 treated recipients. In total, we conclude that use of this novel combinatorial strategy can suppress pre-clinical GVHD and posit, in vivo EP11313 treatment might be useful combined with Treg expansion therapy for treatment of diseases involving inflammatory responses.

SUBMITTER: Copsel SN

PROVIDER: S-EPMC6353853 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Publications

BET Bromodomain Inhibitors Which Permit Treg Function Enable a Combinatorial Strategy to Suppress GVHD in Pre-clinical Allogeneic HSCT.

Copsel Sabrina N SN Lightbourn Casey O CO Barreras Henry H Lohse Ines I Wolf Dietlinde D Bader Cameron S CS Manov John J Kale Brandon J BJ Shah Devangi D Brothers Shaun P SP Perez Victor L VL Komanduri Krishna V KV Wahlestedt Claes C Levy Robert B RB

Frontiers in immunology 20190124

A recent approach for limiting production of pro-inflammatory cytokines has been to target bromodomain and extra-terminal (BET) proteins. These epigenetic readers of histone acetylation regulate transcription of genes involved in inflammation, cardiovascular disease, and cancer. Development of BET inhibitors (BETi) has generated enormous interest for their therapeutic potential. Because inflammatory signals and donor T cells promote graft-versus-host disease (GVHD), regulating both pathways coul ...[more]

PMID: 30733722

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Project description:Regulatory T (Treg) cells play an important role in the induction and maintenance of peripheral tolerance. Treg cells also suppress a variety of other immune responses, including anti-tumor and alloimmune responses. We have previously reported that tumor-activated Treg cells express granzyme B and that granzyme B is important for Treg cell-mediated suppression of anti-tumor immune responses (GSE13409). Here, we report that allogeneic mismatch also induces the expression of granzyme B. Granzyme B-deficient mice challenged with fully mismatched allogeneic P815 mastocytoma cells have markedly improved survival compared to WT and other granzyme- or perforin-deficient mice, suggesting an immunoregulatory role for granzyme B in this setting. Treg cells harvested from the tumor environment of P815-challenged mice express granzyme B. Treg cells also express granzyme B in vitro during mixed lymphocyte reactions and in vivo in a mouse model of graft-versus-host disease (GVHD). However, in contrast to findings from our previously published tumor model, granzyme B is not required for the suppression of effector T cell (Teff) proliferation in in vitro Treg suppression assays stimulated by either Concanavalin A or allogeneic antigen presenting cells. Additionally, in an ex vivo assay, sort-purified in vivo-activated CD4+Foxp3+ Treg cells from mice with active GVHD -- under conditions known to induce granzyme B expression in Treg cells -- suppressed Teff cell proliferation in a granzyme B-independent manner. Adoptive transfer of naive granzyme B-deficient CD4+CD25+ Treg cells into a mouse model of GVHD rescued hosts from lethatlity equivalently to naive wild-type Treg cells. Serum analysis of GVHD-associated cytokine production in these recipients also demonstrated that Treg cells suppressed production of IL-2, IL-4, IL-5, GM-CSF, and IFN-gamma in a granzyme B-independent manner. In order to determine whether the context in which Treg cells are activated alters the intrinsic properties of Treg cells, we used Foxp3 reporter mice to obtain gene expression profiles of CD4+Foxp3+ Treg cells purifed from naive resting spleens, spleens from mice with acute GVHD, and from ascites fluid of mice challenged intraperitoneally with allogeneic P815 tumor cells. Unsupervised analyses revealed distinct activation signatures of Treg cells among the 3 experimental groups. Taken together, these findings demonstrate that granzyme B is not required for Treg cell-mediated suppression of GVHD, which is in contrast to what we have previously reported for Treg cell function in the setting of tumor challenge. Cell intrinsic differences could partially account for these differential phenotypes. These data also suggest the therapeutic potential of targeting specific Treg cell suppressive functions in order to segregate GVHD and graft-versus-tumor effector functions. Experiment Overall Design: Six replicates of Naive CD4+Foxp3+ Treg cells were purified from resting spleens, five replicates of allogeneic tumor-activated Treg cells and three samples of GVHD-activated Treg cells. Experiment Overall Design: Naive reps 1-3 are controls for the GVHD-activated samples. Experiment Overall Design: Naive reps 4-6 are controls for the Allogeneic tumor-activated samples.

Dataset Information

BET Bromodomain Inhibitors Which Permit Treg Function Enable a Combinatorial Strategy to Suppress GVHD in Pre-clinical Allogeneic HSCT.

Publications

BET Bromodomain Inhibitors Which Permit Treg Function Enable a Combinatorial Strategy to Suppress GVHD in Pre-clinical Allogeneic HSCT.

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