Targeting histone/protein deacetylase (HDAC)-6, -9, or Sirtuin-1 (Sirt1) augments the suppressive functions of Foxp3+ T regulatory (Treg) cells, but it is unclear if this involves different mechanisms, such that combined inhibition would be beneficial. We compared the suppressive functions of Tregs from wild-type C57BL/6 mice or mice with global (HDAC6-/-, HDAC9-/-, dual HDAC6/9-/-) or conditional deletion (CD4-Cre or Foxp3-Cre and floxed Sirt1; GSE26425) alone, or after treatment with isoform-selective HDAC inhibitors (HDACi). We found the heat shock response was crucial in mediating the effects of HDAC6, but not Sirt1 inhibition. Furthermore, while HDAC6, HDAC9 and Sirt1 all deacetylate Foxp3, each has diverse effects on Foxp3 transcription, and loss of HDAC9 is associated with stabilization of Stat5 acetylation and its transcriptional activity. Targeting different HDAC can increase Treg function by multiple and additive mechanisms, indicating the therapeutic potential for combinations of HDACi in the management of autoimmunity and alloresponses post-transplant.
Histone deacetylases 6 and 9 and sirtuin-1 control Foxp3+ regulatory T cell function through shared and isoform-specific mechanisms.
No sample metadata fields
View SamplesWe investigated the role of DNMT1 in immune homeostasis by generating mice lacking DNMT1 in Foxp3+ T-regulatory (Treg) cells. These mice showed decreased peripheral Foxp3+ Tregs, complete loss of Foxp3+ Treg suppressive functions in vitro and in vivo, and died from autoimmunity by 3-4 weeks unless they received perinatal transfer of wild-type Tregs that prolonged their survival. Methylation of CpG-sites in the TSDR region of Foxp3 was unaffected by DNMT1 deletion, but microarray revealed more >500 proinflammatory and other genes were upregulated in DNMT1-/- Tregs. CD4-Cre-mediated DNMT1 deletion showed inability of conventional T cells to convert to Foxp3+ Treg under appropriate polarizing conditions. Hence, DNMT1 is absolutely necessary for maintenance of the gene program required for normal Treg development and function.
Foxp3+ T-regulatory cells require DNA methyltransferase 1 expression to prevent development of lethal autoimmunity.
Specimen part
View SamplesTreg dysfunction is associated with a variety of inflammatory diseases. Treg populations are defined by expression of the oligomeric transcription factor FOXP3 and inability to produce IL-2, a cytokine required for T cell maintenance and survival. FOXP3 activity is regulated post-translationally by histone/protein acetyltransferases and histone/protein deacetylases (HDACs). Here, we determined that HDAC3 mediates both the development and function of the two main Treg subsets, thymus-derived Tregs and induced Tregs (iTregs). We determined that HDAC3 and FOXP3 physically interact and that HDAC3 expression markedly reduces Il2 promoter activity. In murine models, conditional deletion of Hdac3 during thymic Treg development restored Treg production of IL-2 and blocked the suppressive function of Tregs. HDAC3-deficient mice died from autoimmunity by 4-6 weeks of age; however, injection of WT FOXP3+ Tregs prolonged survival. Adoptive transfer of Hdac3-deficient Tregs, unlike WT Tregs, did not control T cell proliferation in naive mice and did not prevent allograft rejection or colitis. HDAC3 also regulated the development of iTregs, as HDAC3-deficient conventional T cells were not converted into iTregs under polarizing conditions and produced large amounts of IL-2, IL-6, and IL-17. We conclude that HDAC3 is essential for the normal development and suppressive functions of thymic and peripheral FOXP3+ Tregs.
FOXP3+ regulatory T cell development and function require histone/protein deacetylase 3.
Specimen part
View SamplesT-regulatory (Treg) cells are important to immune homeostasis, and Treg cell deficiency or dysfunction leads to autoimmune disease. An histone/protein acetyltransferase (HAT), p300, was recently found important for Treg function and stability, but further insights into the mechanisms by which p300 or other HATs affect Treg biology are needed. Here we show that CBP, a p300 paralog, is also important in controlling Treg function and stability. Thus, while mice with Treg-specific deletion of CBP or p300 developed minimal autoimmune disease, the combined deletion of CBP and p300 led to fatal autoimmunity by 3-4 weeks of age. The effects of CBP and p300 deletion on Treg development are dose-dependent, and involve multiple mechanisms. CBP and p300 cooperate with several key Treg transcription factors that act on the Foxp3 promoter to promote Foxp3 production. CBP and p300 also act on the Foxp3 CNS2 region to maintain Treg stability in inflammatory environments by regulating pCREB function and GATA3 expression, respectively. Lastly, CBP and p300 regulate the epigenetic status and function of Foxp3. Our findings provide insights into how HATs orchestrate multiple aspects of Treg development and function, and identify overlapping but also discrete activities for p300 and CBP in control of Treg cells.
Two histone/protein acetyltransferases, CBP and p300, are indispensable for Foxp3+ T-regulatory cell development and function.
No sample metadata fields
View SamplesElectrochemical gradients of monovalent cations across the plasma membrane (high intracellular potassium, [K+]i vs low intracellular sodium, [Na+]i) are created by the Na+,K+-pump and determine a large variety of physiologically important processes. We hypothesized that transcriptomics changes triggered by hypoxia are at least partially caused by Na+i/K+i-mediated excitation-transcription coupling .
Transcriptomic changes triggered by hypoxia: evidence for HIF-1α-independent, [Na+]i/[K+]i-mediated, excitation-transcription coupling.
Specimen part
View SamplesFoxp3+ T-regulatory cells (Tregs) are key to immune homeostasis such that their diminished numbers or function can cause autoimmunity and allograft rejection. Foxp3+ Tregs express histone/protein deacetylases (HDACs) that regulate chromatin remodeling, gene expression and protein function. Pan-HDAC inhibitors developed for oncology enhance Treg production and suppression but have limited non-oncologic applications given their broad effects. We show, using HDAC6-deficient mice and WT mice treated with HDAC6-specific inhibitors, that HDAC6 inhibition promotes Treg suppressive activity in models of inflammation and autoimmunity, including multiple forms of experimental colitis and fully MHC-incompatible cardiac allograft rejection. Many of the beneficial effects of HDAC6 targeting are also achieved by inhibition of the HDAC6-regulated protein, HSP90. Hence, selective targeting of a single HDAC isoform, HDAC6, or its downstream target, HSP90, can promote Treg-dependent suppression of autoimmunity and transplant rejection.
Histone deacetylase 6 and heat shock protein 90 control the functions of Foxp3(+) T-regulatory cells.
No sample metadata fields
View SamplesFoxp3+ T-regulatory (Treg) cells maintain immune homeostasis and limit autoimmunity, but can also curtail host responses to cancers. Tregs are therefore promising targets to enhance anti-tumor immunity. Histone/protein acetyltransferases (HATs) promote chromatin accessibility, gene transcription and the function of multiple transcription factors and non-histone proteins. We found that conditional deletion or pharmacologic inhibition of one specific HAT, p300, in Foxp3+ Tregs, increased TCR-induced apoptosis in Tregs, impaired Treg suppressive function and iTreg peripheral conversion, and limited tumor growth in immunocompetent, but not in immunodeficient, hosts. Our data demonstrate that p300 is important for Foxp3+ Treg function and homeostasis in vivo and in vitro, and identify a novel mechanism to diminish Treg function without overtly impairing effector Tcell responses or inducing autoimmunity. Collectively, these data suggest a new approach for cancer immunotherapy.
Inhibition of p300 impairs Foxp3⁺ T regulatory cell function and promotes antitumor immunity.
Specimen part
View SamplesWe previously showed that a diet containing phloridzin suppressed the blood glucose levels in streptozotocin-induced diabetic mice most likely by inhibiting glucose absorption from the small intestine. In this study, we showed that 0.5% and 1% phloridzin diets significantly reduce the blood glucose levels in healthy normal BALB/c mice after 7 days of feeding.
Phloridzin reduces blood glucose levels and alters hepatic gene expression in normal BALB/c mice.
Sex, Specimen part
View SamplesQuercetin is a food component that may ameliorate the diabetic symptoms. We examined hepatic gene expression of BALB/c mice with streptozotocin (STZ)-induced diabetes to elucidate the mechanism of the protective effect of dietary quercetin on diabetes-associated liver injury.
Dietary quercetin alleviates diabetic symptoms and reduces streptozotocin-induced disturbance of hepatic gene expression in mice.
Sex, Specimen part
View SamplesWe showed that diets containing 0.1% or 0.5% quercetin lowered the STZ-induced increase in blood glucose levels and improved plasma insulin levels. A cluster analysis of the hepatic gene expressions showed that 0.5% quercetin diet suppressed STZ-induced alteration of gene expression. Gene set enrichment analysis (GSEA) and quantitative RT-PCR analysis showed that the quercetin diets had their greatest suppressive effect on the STZ-induced elevation of expression of cyclin dependent kinase inhibitor p21(WAF1/Cip1) (Cdkn1a).
Dietary quercetin alleviates diabetic symptoms and reduces streptozotocin-induced disturbance of hepatic gene expression in mice.
Sex, Specimen part
View Samples