Gene regulation in eukaryotes requires the coordinate interaction of chromatin-modulating proteins with specific transcription factors such as the androgen receptor. Gene activation and repression is specifically regulated by histone methylation status at distinct lysine residues. Here we show that lysine-specific demethylase 1 (LSD1; also known as BHC110) co-localizes with the androgen receptor in normal human prostate and prostate tumour. LSD1 interacts with androgen receptor in vitro and in vivo, and stimulates androgen-receptor-dependent transcription. Conversely, knockdown of LSD1 protein levels abrogates androgen-induced transcriptional activation and cell proliferation. Chromatin immunoprecipitation analyses demonstrate that androgen receptor and LSD1 form chromatin-associated complexes in a ligand-dependent manner. LSD1 relieves repressive histone marks by demethylation of histone H3 at lysine 9 (H3-K9), thereby leading to de-repression of androgen receptor target genes. Furthermore, we identify pargyline as an inhibitor of LSD1. Pargyline blocks demethylation of H3-K9 by LSD1 and consequently androgen-receptor-dependent transcription. Thus, modulation of LSD1 activity offers a new strategy to regulate androgen receptor functions. Here, we link demethylation of a repressive histone mark with androgen-receptor-dependent gene activation, thus providing a mechanism by which demethylases control specific gene expression.

CD103+ dendritic cells (DCs) in nonlymphoid tissues are specialized in the cross-presentation of cell-associated antigens. However, little is known about the mechanisms that regulate the development of these cells. We show that two populations of CD11c+MHCII+ cells separated on the basis of CD103 and CD11b expression coexist in most nonlymphoid tissues with the exception of the lamina propria. CD103+ DCs are related to lymphoid organ CD8+ DCs in that they are derived exclusively from pre-DCs under the control of fms-like tyrosine kinase 3 (Flt3) ligand, inhibitor of DNA protein 2 (Id2), and IFN regulatory protein 8 (IRF8). In contrast, lamina propria CD103+ DCs express CD11b and develop independently of Id2 and IRF8. The other population of CD11c+MHCII+ cells in tissues, which is CD103−CD11b+, is heterogenous and depends on both Flt3 and MCSF-R. Our results reveal that nonlymphoid tissue CD103+ DCs and lymphoid organ CD8+ DCs derive from the same precursor and follow a related differentiation program.

Aerobic glycolysis (the Warburg effect) is a metabolic hallmark of activated T cells, and has been implicated in augmenting effector T cell responses including expression of the pro-inflammatory cytokine interferon (IFN)-γ via 3′ untranslated region (3′UTR)-mediated mechanisms. Here we show that lactate dehydrogenase A (LDHA) is induced in activated T cells to support aerobic glycolysis, but promotes IFN-γ expression independently of its 3′UTR. Instead, LDHA maintains high levels of acetyl-CoA to enhance histone acetylation and transcription of Ifng. Ablation of LDHA in T cells protects mice from immunopathology triggered by excessive IFN-γ expression or deficiency of regulatory T cells. These findings reveal an epigenetic mechanism by which aerobic glycolysis promotes effector T cell differentiation, and suggest that LDHA may be targeted therapeutically in autoinflammtory diseases.

Posttranslational modifications of histones, such as methylation, regulate chromatin structure and gene expression. Recently, lysine-specific demethylase 1 (LSD1), the first histone demethylase, was identified. LSD1 interacts with the androgen receptor and promotes androgen-dependent transcription of target genes by ligand-induced demethylation of mono- and dimethylated histone H3 at Lys 9 (H3K9) only. Here, we identify the Jumonji C (JMJC) domain-containing protein JMJD2C as the first histone tridemethylase regulating androgen receptor function. JMJD2C interacts with androgen receptor in vitro and in vivo. Assembly of ligand-bound androgen receptor and JMJD2C on androgen receptor-target genes results in demethylation of trimethyl H3K9 and in stimulation of androgen receptor-dependent transcription. Conversely, knockdown of JMJD2C inhibits androgen-induced removal of trimethyl H3K9, transcriptional activation and tumour cell proliferation. Importantly, JMJD2C colocalizes with androgen receptor and LSD1 in normal prostate and in prostate carcinomas. JMJD2C and LSD1 interact and both demethylases cooperatively stimulate androgen receptor-dependent gene transcription. In addition, androgen receptor, JMJD2C and LSD1 assemble on chromatin to remove methyl groups from mono, di and trimethylated H3K9. Thus, our data suggest that specific gene regulation requires the assembly and coordinate action of demethylases with distinct substrate specificities.

Regulatory T (Treg) cells, characterized by expression of the transcription factor forkhead box P3 (Foxp3), maintain immune homeostasis by suppressing self-destructive immune responses1–4. Foxp3 operates as a late-acting differentiation factor controlling Treg cell homeostasis and function5, whereas the early Treg-cell-lineage commitment is regulated by the Akt kinase and the forkhead box O (Foxo) family of transcription factors6–10. However, whether Foxo proteins act beyond the Treg-cell-commitment stage to control Treg cell homeostasis and function remains largely unexplored. Here we show that Foxo1 is a pivotal regulatorof Treg cell function. Treg cells express high amounts of Foxo1 and display reduced T-cell-receptor-induced Akt activation, Foxo1 phosphorylation and Foxo1 nuclear exclusion. Mice with Treg-cell-specific deletion of Foxo1 develop a fatal inflammatory disorder similar in severity to that seen in Foxp3-deficient mice, but without the loss of Treg cells. Genome-wide analysis of Foxo1 binding sites reveals ~300 Foxo1-bound target genes, including the pro-inflammatory cytokine Ifng, that do not seem to be directly regulated by Foxp3. These findings show that the evolutionarily ancient Akt–Foxo1 signalling module controls a novel genetic program indispensable for Treg cell function.

To determine site and mechanism of suppression, regulatory T cell (Treg) migration and function were investigated in an islet allograft model. Treg first migrated from blood to the inflammed allografts, this depended on CCR2, CCR4, CCR5, and P- and E-selectin ligands, and was essential for suppression of alloimmunity. In the allograft, Treg were activated, upregulated effector molecules, migrated to the draining lymph nodes (dLN) in a CCR2, CCR5, and CCR7 fashion, and this movement was essential for optimal suppression. Treg inhibited dendritic cell migration in a TGFβ and IL-10 dependent fashion; and suppressed antigen specific T effector cell migration, accumulation, and proliferation in dLNs and allografts. These results showed that sequential migration from blood to the target tissue and then to dLNs were required for nTreg to differentiate and execute fully their suppressive function, by inhibiting DC in the peripheral tissue, and T effector cell responses in dLN and allografts.

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Posttranslational modifications of histones such as methylation, acetylation, and phosphorylation regulate chromatin structure and gene expression. Here we show that protein kinase C-related kinase 1 (PRK1) phosphorylates histone H3 at threonine 11 (H3T11) upon ligand-dependent recruitment to androgen receptor (AR) target genes. PRK1 is pivotal to AR function since PRK1 knockdown or inhibition impedes AR-dependent transcription. Blocking PRK1 function abrogates androgen-induced H3T11 phosphorylation, and inhibits androgen-induced demethylation of histone H3. Moreover, serine 5-phosphorylated RNA polymerase II is no longer observed at AR target promoters. Phosphorylation of H3T11 by PRK1 accelerates demethylation by the Jumonji C (JmjC) domain-containing protein JMJD2C. Thus, phosphorylation of H3T11 by PRK1 establishes a novel chromatin mark for gene activation, identifying PRK1 as a gatekeeper of ARdependent transcription. Importantly, levels of PRK1 and phosphorylated H3T11 correlate with Gleason scores of prostate carcinomas. Finally, inhibition of PRK1 blocks AR-induced tumour cell proliferation, making PRK1 a promising therapeutic target. Keywords PRK1; androgen receptor; histone phosphorylation; prostate cancerThe N-terminal tails of histones are subject to a plethora of posttranslational modifications such as methylation, acetylation, and phosphorylation by specific chromatin-modifying enzymes1. During gene expression, these modifications influence chromatin structure to facilitate the assembly of the RNA polymerase II transcription machinery1 , 2. Androgen receptor (AR)-dependent gene expression is characterized by changes in chromatin