Histone Demethylase JMJD3 Research Articles

Fasting-induced FGF21 signaling activates hepatic autophagy and lipid degradation via JMJD3 histone demethylase

Autophagy is essential for cellular survival and energy homeostasis under nutrient deprivation. Despite the emerging importance of nuclear events in autophagy regulation, epigenetic control of autophagy gene transcription remains unclear. Here, we report fasting-induced Fibroblast Growth Factor-21 (FGF21) signaling activates hepatic autophagy and lipid degradation via Jumonji-D3 (JMJD3/KDM6B) histone demethylase. Upon FGF21 signaling, JMJD3 epigenetically upregulates global autophagy-network genes, including Tfeb, Atg7, Atgl, and Fgf21, through demethylation of histone H3K27-me3, resulting in autophagy-mediated lipid degradation. Mechanistically, phosphorylation of JMJD3 at Thr-1044 by FGF21 signal-activated PKA increases its nuclear localization and interaction with the nuclear receptor PPARα to transcriptionally activate autophagy. Administration of FGF21 in obese mice improves defective autophagy and hepatosteatosis in a JMJD3-dependent manner. Remarkably, in non-alcoholic fatty liver disease patients, hepatic expression of JMJD3, ATG7, LC3, and ULK1 is substantially decreased. These findings demonstrate that FGF21-JMJD3 signaling epigenetically links nutrient deprivation with hepatic autophagy and lipid degradation in mammals.

The repositioning of epigenetic probes/inhibitors identifies new anti-schistosomal lead compounds and chemotherapeutic targets.

Praziquantel represents the frontline chemotherapy used to treat schistosomiasis, a neglected tropical disease (NTD) caused by infection with macro-parasitic blood fluke schistosomes. While this drug is safe, its inability to kill all schistosome lifecycle stages within the human host often requires repeat treatments. This limitation, amongst others, has led to the search for novel anti-schistosome replacement or combinatorial chemotherapies. Here, we describe a repositioning strategy to assess the anthelmintic activity of epigenetic probes/inhibitors obtained from the Structural Genomics Consortium. Thirty-seven epigenetic probes/inhibitors targeting histone readers, writers and erasers were initially screened against Schistosoma mansoni schistosomula using the high-throughput Roboworm platform. At 10 μM, 14 of these 37 compounds (38%) negatively affected schistosomula motility and phenotype after 72 hours of continuous co-incubation. Subsequent dose-response titrations against schistosomula and adult worms revealed epigenetic probes targeting one reader (NVS-CECR2-1), one writer (LLY-507 and BAY-598) and one eraser (GSK-J4) to be particularly active. As LLY-507/BAY-598 (SMYD2 histone methyltransferase inhibitors) and GSK-J4 (a JMJD3 histone demethylase inhibitor) regulate an epigenetic process (protein methylation) known to be critical for schistosome development, further characterisation of these compounds/putative targets was performed. RNA interference (RNAi) of one putative LLY-507/BAY-598 S. mansoni target (Smp_000700) in adult worms replicated the compound-mediated motility and egg production defects. Furthermore, H3K36me2, a known product catalysed by SMYD2 activity, was also reduced by LLY-507 (25%), BAY-598 (23%) and siSmp_000700 (15%) treatment of adult worms. Oviposition and packaging of vitelline cells into in vitro laid eggs was also significantly affected by GSK-J4 (putative cell permeable prodrug inhibitor of Smp_034000), but not by the related structural analogue GSK-J1 (cell impermeable inhibitor). Collectively, these results provide further support for the development of next-generation drugs targeting schistosome epigenetic pathway components. In particular, the progression of histone methylation/demethylation modulators presents a tractable strategy for anti-schistosomal control.

Antiproliferative effect of the histone demethylase inhibitor GSK-J4 in chondrosarcomas.

Chondrosarcoma (CS) is the second most common malignant bone sarcoma. Its treatment remains an issue, because this tumor is radio- and chemo-resistant. In the present study, we investigated the antitumoral potential of GSK-J4, a small molecule described as an inhibitor of histone demethylases UTX and JMJD3 (KDM6A and KDM6B), alone or in combination with cisplatin in CSs. Human CS-derived cell lines were treated with GSK-J4 in the presence or not of cisplatin. Survival curves were established and cell proliferation and cycle were evaluated by flow cytometry using dividing cell tracking technique utilizing carboxyfluorescein succinimidyl ester labeling, or DNA staining by propidium iodide. Apoptosis and senescence were also investigated. GSK-J4 decreased proliferation of CS cells. Additionally, it induced apoptosis in CH2879 and JJ012 cells, but not in SW1353 CSs. In addition, its association with cisplatin decreased cell proliferation more than drugs alone, whereas it did not increase apoptosis compared to cisplatin alone. Interestingly, GSK-J4 alone as well as in association with cisplatin did not affect chondrocyte survival or proliferation. In conclusion, this study suggests that demethylase inhibitors may be useful in improving therapy for CS in reducing its proliferation.

Histone demethylase Jmjd3 modulates osteoblast apoptosis induced by tumor necrosis factor-alpha through directly targeting RASSF5

ABSTRACT Purpose: Regulation of gene expression is fine-tuned by a dynamic equilibrium between repressive modifications and transcriptional activation of histone tails. Jumonji domain-containing 3 (Jmjd3), also known as KDM6B, is a specific histone demethylase for trimethylation on histone H3 lysine 27 (H3K27me3) that specifically removes the methylation of H3K27me3 and promotes gene expression. Our previous study showed that Jmjd3 inhibits serum deprivation-induced osteoblast apoptosis. In this study, we clarified the role of Jmjd3 in tumor necrosis factor-alpha (TNF-α)-induced osteoblast apoptosis. Materials and Methods: Jmjd3 activity was inhibited by GSK-J4. Transfection of osteoblastic murine MC3T3-E1 cells with short hairpin RNA (shRNA) was used to establish stable Jmjd3 knockdown cells. Osteoblast apoptosis was detected using Annexin V-APC/PI staining, cysteinyl aspartate specific protease-3 (caspase-3) activity assays, and Western blot. Real-time polymerase chain reaction (PCR) and chromatin immunoprecipitation (ChIP) assays were performed to clarify the mechanism responsible for Jmjd3-regulated osteoblast apoptosis induced by TNF-α. Results: Based on Annexin V-APC/PI staining, caspase-3 activation, and poly ADP-ribose polymerase (PARP) cleavage, pretreatment with GSK-J4 and knockdown of Jmjd3 by shRNA transfection each inhibited osteoblast apoptosis. Furthermore, knockdown of Jmjd3 decreased the expression of Ras association domain family 5 (RASSF5), which is a pro-apoptotic gene of the Ras associated domain family. H3K27me3 levels in the promoter region of RASSF5 were up-regulated in the Jmjd3 knockdown cells. Conclusions: Jmjd3 regulated TNF-α-induced osteoblast apoptosis by targeting RASSF5.

Glutaminolysis Epigenetically Regulates Antiapoptotic Gene Expression in Idiopathic Pulmonary Fibrosis Fibroblasts.

Fibrotic responses involve multiple cellular processes, including epigenetic changes. Epigenetic changes are sensitive to alterations in the tissue microenvironment such as the flux of tricarboxylic acid (TCA) cycle metabolites. TCA metabolites directly regulate epigenetic states, in part by regulating histone modification-related enzymes. Glutaminolysis is a critical metabolic process by which glutamine is converted to glutamate by glutaminase and then to α-ketoglutarate (α-KG), a TCA cycle metabolite. Idiopathic pulmonary fibrosis (IPF) is a disease characterized by aberrant metabolism, including enhanced glutaminolysis. IPF fibroblasts are apoptosis resistant. In this study, we explored the relationship between glutaminolysis and the resistance to apoptosis of IPF fibroblasts. Inhibition of glutaminolysis decreased expression of XIAP and survivin, members of the inhibitor of apoptosis protein (IAP) family. α-KG is a cofactor for JMJD3 histone demethylase, which targets H3K27me3. In the absence of glutamine, JMJD3 activity in fibroblasts is significantly decreased, whereas H3K27me3 levels are increased. Chromatin immunoprecipitation assays confirmed that JMJD3 directly interacts with XIAP and survivin promoter regions in a glutamine-dependent manner. Exogenous α-KG partially restores JMJD3 function and its interaction with the XIAP and survivin promoter regions under glutamine-deficient conditions. Interestingly, α-KG upregulates XIAP, but not survivin, suggesting differential α-KG-dependent and -independent mechanisms by which glutamine regulates these IAPs. Our data demonstrate a novel mechanism of metabolic regulation in which glutaminolysis promotes apoptosis resistance of IPF fibroblasts through epigenetic regulation of XIAP and survivin.

An RNA Aptamer Targeting the Receptor Tyrosine Kinase PDGFRα Induces Anti-tumor Effects through STAT3 and p53 in Glioblastoma

Human glioblastoma (GBM) is the most aggressive malignancy of the CNS, with less than 5% survival. Despite great efforts to find effective therapeutics, current options remain very limited. To develop a targeted cancer therapeutic, we selected RNA aptamers against platelet-derived growth factor receptor α (PDGFRα), which is a receptor tyrosine kinase. One RNA aptamer (PDR3) with high affinity (0.25 nM) showed PDGFRα specificity and was internalized in U251-MG cells. Following treatment with the PDR3 aptamer, expression of the transcription factor STAT3 (signal transducer and activator of transcription 3) was inhibited, whereas the expression of the histone demethylase JMJD3 and the tumor suppressor p53 were upregulated. PDR3 also upregulated serine phosphorylation of p53, which subsequently mediated apoptosis through the death receptors: tumor necrosis factor (TNF)-related apoptosis-inducing ligand receptors 1/2 (TRAIL-R1/R2), Fas-associated via death domain (FADD), and Fas. PDR3 significantly decreased cell viability in a dose-dependent manner. Furthermore, translocation of PDR3 into the nucleus induced hypomethylation at the promoters of cyclin D2. To assess the feasibility of targeted delivery, we conjugated PDR3 aptamer with STAT3-siRNA for a chimera. The PDR3-siSTAT3 chimera successfully inhibited the expression of target genes and showed significant inhibition of cell viability. In summary, our results show that well-tailored RNA aptamers targeting the PDGFRα-STAT3 axis have the potential to act as anti-cancer therapeutics in GBM.

Critical Role of Histone Demethylase Jmjd3 in T Cell Migration

Jmjd3, a histone H3K27 demethylase, is known to play a critical role in macrophage and T cell differentiation, but its role in T cell migration and T cell memory maintenance remains largely unknown. In this study, we show that Jmjd3 deficiency resulted in multiple alterations in T cell migration. Jmjd3 deletion limits CD4+ T cells egress out of the thymus, leading to thymic T-cell accumulation and peripheral lymphoid organ T-cell reduction. Gene profiling analysis of wild-type and Jmjd3-deficient CD4+ T cells identified altered expression of Jmjd3 target genes that correlated with changes in H3K27 and/or H3K4 trimethylation in promoters and gene body regions. The expression of the Jmjd3 target gene Pdlim4 is also regulated by Klf2, which regulates T-cell migration. Thus, our findings identify a novel Jmjd3 target gene, Pdlim4, in CD4+ T cell migration and provide insight into the molecular mechanisms by which Jmjd3 regulates T-cell migration. DisclosuresNo relevant conflicts of interest to declare.

USP7 Cooperates with NOTCH1 to Drive the Oncogenic Transcriptional Program in T-Cell Leukemia.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive disease, affecting children and adults. Chemotherapy treatments show high response rates but have debilitating effects and carry risk of relapse. Previous work implicated NOTCH1 and other oncogenes. However, direct inhibition of these pathways affects healthy tissues and cancer alike. Our goal in this work has been to identify enzymes active in T-ALL whose activity could be targeted for therapeutic purposes. To identify and characterize new NOTCH1 druggable partners in T-ALL, we coupled studies of the NOTCH1 interactome to expression analysis and a series of functional analyses in cell lines, patient samples, and xenograft models. We demonstrate that ubiquitin-specific protease 7 (USP7) interacts with NOTCH1 and controls leukemia growth by stabilizing the levels of NOTCH1 and JMJD3 histone demethylase. USP7 is highly expressed in T-ALL and is transcriptionally regulated by NOTCH1. In turn, USP7 controls NOTCH1 levels through deubiquitination. USP7 binds oncogenic targets and controls gene expression through stabilization of NOTCH1 and JMJD3 and ultimately H3K27me3 changes. We also show that USP7 and NOTCH1 bind T-ALL superenhancers, and inhibition of USP7 leads to a decrease of the transcriptional levels of NOTCH1 targets and significantly blocks T-ALL cell growth in vitro and in vivo. These results provide a new model for USP7 deubiquitinase activity through recruitment to oncogenic chromatin loci and regulation of both oncogenic transcription factors and chromatin marks to promote leukemia. Our studies also show that targeting USP7 inhibition could be a therapeutic strategy in aggressive leukemia.

334 - Histone demethylase JMJD3 regulates a copper-containing lysyl oxidase expression in THP-1 cell-derived M2-macrophages

Lysyl oxidase (LOX) is a copper-containing amine oxidase that plays a key role in the regulation of extracellular stiffness through the cross-linking of collagen. It has been considered that excess production of LOX participated in the progression of tumor cell metastasis; however, LOX regulation has not been fully elucidated. To determine the molecular mechanisms involved in LOX expression, we used human monocytic THP-1 cell-derived M2-macrophages that participated in the tumor progression. Our results revealed that LOX expression was significantly induced in IL4/IL13-elicited M2-macrophages that was accompanied with the significant induction of CD206 and arginase-1, M2-macrophage markers. On the other hand, LOX induction was not observed in IFNγ/LPS-elicited M1-macrophages. These data are consistent with high LOX expression in metastatic human breast cancer MDA-MB-231 cells. According to the significant involvement of epigenetics in tumor progression, histone modifications including acetylation and methylation in M2-macrophages was investigated. Among histone modifications, the level of histone H3K27me3, an epigenetic marker for transcription suppression, was decreased in M2-macrophages. Based on the previous findings that histone demethylase JMJD3 participated in M2-macrophage differentiation, we investigated the involvement of JMJD3 in LOX induction. As expected, LOX induction was significantly suppressed in the presence of JMJD3 inhibitor, GSK-J4. However, histone deacetylase inhibitor and DNA demethylation reagent did not induce LOX expression, suggesting that JMJD3-mediated histone demethylation could be a key histone modification in LOX expression. Moreover, our ChIP results clearly showed that the level of H3K27me3 within the proximal LOX promoter was decreased. Overall, we have determined that H3K27 methylation is involved in the regulation of LOX expression in THP-1 cell-derived M2-macrophages.

Prenatal 25-hydroxyvitamin D deficiency affects development of atopic dermatitis via DNA methylation

Prenatal 25-hydroxyvitamin D deficiency affects development of atopic dermatitis via DNA methylation

Forskolin Sensitizes Human Acute Myeloid Leukemia Cells to H3K27me2/3 Demethylases GSKJ4 Inhibitor via Protein Kinase A.

Acute myeloid leukemia (AML) is an aggressive hematological malignancy occurring very often in older adults, with poor prognosis depending on both rapid disease progression and drug resistance occurrence. Therefore, new therapeutic approaches are demanded. Epigenetic marks play a relevant role in AML. GSKJ4 is a novel inhibitor of the histone demethylases JMJD3 and UTX. To note GSKJ4 has been recently shown to act as a potent small molecule inhibitor of the proliferation in many cancer cell types. On the other hand, forskolin, a natural cAMP raising compound, used for a long time in traditional medicine and considered safe also in recent studies, is emerging as a very interesting molecule for possible use in cancer therapy. Here, we investigate the effects of forskolin on the sensitivity of human leukemia U937 cells to GSKJ4 through flow cytometry-based assays (cell-cycle progression and cell death), cell number counting, and immunoblotting experiments. We provide evidence that forskolin markedly potentiates GSKJ4-induced antiproliferative effects by apoptotic cell death induction, accompanied by a dramatic BCL2 protein down-regulation as well as caspase 3 activation and PARP protein cleavage. Comparable effects are observed with the phosphodiesterase inhibitor IBMX and 8-Br-cAMP analogous, but not by using 8-pCPT-2′-O-Me-cAMP Epac activator. Moreover, the forskolin-induced enhancement of sensitivity to GSKJ4 is counteracted by pre-treatment with Protein Kinase A (PKA) inhibitors. Altogether, our data strongly suggest that forskolin sensitizes U937 cells to GSKJ4 inhibitor via a cAMP/PKA-mediated mechanism. Our findings provide initial evidence of anticancer activity induced by forskolin/GSKJ4 combination in leukemia cells and underline the potential for use of forskolin and GSKJ4 in the development of innovative and effective therapeutic approaches for AML treatment.

Abstract LB-259: EZH2 inhibitors abrogate upregulation of H3K27me3 by CDK9 inhibitors and potentiate its antitumor activity in DLBCL

Abstract Despite recent improvements in treatment, a significant fraction of patients with diffuse large B-cell lymphoma (DLBCL) still fail therapy. Therefore, new treatments are still needed to advance the cure rate. Cyclin-dependent kinase 9 (CDK9) constitutes positive transcription elongation factor b, which is responsible for the transcription elongation of most of the protein-coding genes through the phosphorylation of the carboxyl-terminal domain of RNA polymerase II at the serine 2. Research indicates that CDK9 is involved in lymphocyte differentiation and activation, and shows an aberrant expression in DLBCL. In addition, Mcl-1 expression, which can be downregulated by CDK9 inhibition, was found to be overexpressed in a significant fraction of DLBCL, contributing to therapy resistance. All these suggest that CDK9 inhibition seems to be a potential therapeutic strategy for DLBCL. LS-007 is a novel CDK9 inhibitor, which displays potential activity against leukemia and ovarian cancer. So, firstly, the therapeutic potential of LS-007 in DLBCL was assessed. We found that LS-007 triggered apoptosis and dramatically repressed DLBCL cell growth associated with lost Mcl-1 and XIAP proteins owing to CDK9 inhibition in vitro and in vivo. However, we also found that CDK9 inhibition specifically elevated the trimethylation of H3K27 (H3K27me3) by mass spectrometry and western blot. Methylation of lysine 27 on H3 is a modification associated with gene repression, and plays a critical role in regulating the expression of genes that determine the balance between cell differentiation and proliferation. This modification is generated by the polycomb repressive complex 2, composed of the SET domain-containing histone methyltransferase EZH2, and accessory proteins EED, SUZ12, and RbAp48. However, the methylation can be removed by the histone demethylases UTX and JMJD3. Accumulating studies imply that H3K27me3 is closely engaged in the development of DLBCL, especially germinal center B cell subtype11. And reducing H3K27me3 level exhibits significant anti-proliferation activity against DLBCL. Considering the important role of the H3K27me3 in tumor progression, we thought that it may restrain CDK9 inhibitors' anti-tumor potency against DLBCL and other solid tumor types. Subsequently, the synergistic effect of the combination therapy of CDK9 inhibitors with EZH2 inhibitors was investigated. As expected, EZH2 inhibitors reversed the upregulation of H3K27me3, improved apoptosis and DNA damage compared to CDK9 inhibitors alone, and synergistically inhibited DLBCL growth in vitro and in vivo. By expanding our studies to other solid tumors with this combination therapy, we also got an impressive synergistic effect. Further, we speculated that CDK9 inhibition reduced the expression of JMJD3/UTX more strongly than that of EZH2, leading to H3K27me3 elevation. To summarize, we found that LS-007 might represent a new therapeutic agent for DLBCL and provide a rational basis for the application of CDK9 inhibitors in combination with EZH2 inhibitors in clinical trials. We know that EZH2 inhibitors only display potent activity in very limited tumor types; however, our data also provide new possibilities for the application of such inhibitors. Citation Format: Shao Xie, Fan Wei, Yiming Sun, Yinglei Gao, Jian Ding, Yi Chen. EZH2 inhibitors abrogate upregulation of H3K27me3 by CDK9 inhibitors and potentiate its antitumor activity in DLBCL [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-259.

Histone Demethylase Jmjd3 Controls T-Cell Trafficking and Persistence by Interacting with Klf2 for Expression of Pdlim4

Abstract Jmjd3, a histone H3K27 demethylase, plays a critical role in gene expression and T-cell differentiation, but its role and mechanisms in T cell trafficking remain poorly understood. Here we have shown that Jmjd3 deficiency in CD4+ T cells resulted in the accumulation of T cells in the thymus, but a reduced number in secondary lymphoid organs. To understand the molecular mechanisms of Jmjd3 action, we identified PDLIM4 as a significantly downregulated target gene in Jmjd3-deficient CD4+ T cells by gene profiling and ChIP-seq analyses. Further investigation shows that Jmjd3 bound to the promoter and gene body regions of PDLIM4 gene and regulated PDLIM4 expression by interacting with zinc finger transcription factor KLF2. Furthermore, we showed that PDLIM4 was involved in filamentous actin (F-actin) remodeling, thus functioning as a key regulator of T cell trafficking. Our findings have identified PDLIM4 as a novel Jmjd3 target gene that affects T-cell trafficking, and provided insights into the molecular mechanisms by which Jmjd3 regulates genes participate in T-cell trafficking.

Histone demethylase JMJD3 regulates fibroblast-like synoviocyte-mediated proliferation and joint destruction in rheumatoid arthritis.

Rheumatoid arthritis (RA) is an immune-mediated disease with the characteristics of progressive joint destruction, deformity, and disability. Epigenetic changes have been implicated in the development of some autoimmune disorders, resulting in an alteration of gene transcription. Here, we investigated how Jumonji C family of histone demethylases (JMJD3) regulated the proliferation and activation of fibroblast-like synoviocytes (FLSs), which are involved in RA joint destruction and pathologic process. The JMJD3 expression and proliferation markers in RA-FLS were higher than those in healthy-FLS and were upregulated in platelet-derived growth factor (PDGF)-induced FLS. Elevated JMJD3 promoted the proliferation and migration of FLS. Treatment with JMJD3 small interfering RNA or inhibitor glycogen synthase kinase (GSK) J4 led to decreased proliferation and migration of FLS. Interestingly, induction of proliferating cell nuclear antigen (PCNA), a major player of the cell-cycle regulation, was correlated with trimethylated lysine 27 in histone H3 loss around the gene promoters. The knockdown of JMJD3 abolished PCNA expression in PDGF-induced FLS and further inhibited cell proliferation and migration, suggesting that JMJD3/PCNA played a crucial role in aspects of FLS proliferation and migration. In vivo, the ability of GSK J4 to hinder collagen-induced arthritis (CIA) in DBA/1 mice was evaluated. We found that GSK J4 markedly attenuated the severity of arthritis in CIA mice. The therapeutic effects were associated with ameliorated joint swelling and reduced bone erosion and destruction. This study revealed how JMJD3 integrated with epigenetic processes to regulate RA-FLS proliferation and invasion. These data suggested that JMJD3 might contribute to rheumatoid synovial hyperplasia and have the potential as a novel therapeutic target for RA.-Jia, W., Wu, W., Yang, D., Xiao, C., Su, Z., Huang, Z., Li, Z., Qin, M., Huang, M., Liu, S., Long, F., Mao, J., Liu, X., Zhu, Y. Z. Histone demethylase JMJD3 regulates fibroblast-like synoviocyte-mediated proliferation and joint destruction in rheumatoid arthritis.

Lineage specific transcription factors and epigenetic regulators mediate TGFβ-dependent enhancer activation.

During neurogenesis, dynamic developmental cues, transcription factors and histone modifying enzymes regulate the gene expression programs by modulating the activity of neural-specific enhancers. How transient developmental signals coordinate transcription factor recruitment to enhancers and to which extent chromatin modifiers contribute to enhancer activity is starting to be uncovered. Here, we take advantage of neural stem cells as a model to unravel the mechanisms underlying neural enhancer activation in response to the TGFβ signaling. Genome-wide experiments demonstrate that the proneural factor ASCL1 assists SMAD3 in the binding to a subset of enhancers. Once located at the enhancers, SMAD3 recruits the histone demethylase JMJD3 and the remodeling factor CHD8, creating the appropriate chromatin landscape to allow enhancer transcription and posterior gene activation. Finally, to analyze the phenotypical traits owed to cis-regulatory regions, we use CRISPR–Cas9 technology to demonstrate that the TGFβ-responsive Neurog2 enhancer is essential for proper neuronal polarization.

The histone demethylase Jmjd3 regulates zebrafish myeloid development by promoting spi1 expression

The histone demethylase Jmjd3 plays a critical role in cell lineage specification and differentiation at various stages of development. However, its function during normal myeloid development remains poorly understood. Here, we carried out a systematic in vivo screen of epigenetic factors for their function in hematopoiesis and identified Jmjd3 as a new epigenetic factor that regulates myelopoiesis in zebrafish. We demonstrated that jmjd3 was essential for zebrafish primitive and definitive myelopoiesis, knockdown of jmjd3 suppressed the myeloid commitment and enhanced the erythroid commitment. Only overexpression of spi1 but not the other myeloid regulators rescued the myeloid development in jmjd3 morphants. Furthermore, preliminary mechanistic studies demonstrated that Jmjd3 could directly bind to the spi1 regulatory region to alleviate the repressive H3K27me3 modification and activate spi1 expression. Thus, our studies highlight that Jmjd3 is indispensable for early zebrafish myeloid development by promoting spi1 expression.

Low HOX gene expression in PML-RARα-positive leukemia results from suppressed histone demethylation

ABSTRACTHomeobox (HOX) genes are frequently dysregulated in leukemia. Previous studies have shown that aberrant HOX gene expression accompanies leukemogenesis and affects disease progression and leukemia patient survival. Patients with acute myeloid leukemia (AML) bearing PML-RARα fusion gene have distinct HOX gene signature in comparison to other subtypes of AML patients, although the mechanism of transcription regulation is not completely understood. We previously found an association between the mRNA levels of HOX genes and those of the histone demethylases JMJD3 and UTX in PML-RARα- positive leukemia patients. Here, we demonstrate that the release of the PML-RARα-mediated block in PML-RARα-positive myeloid leukemia cells increased both JMJD3 and HOX gene expression, while inhibition of JMJD3 using the specific inhibitor GSK-J4 reversed the effect. This effect was driven specifically through PML-RARα fusion protein since expression changes did not occur in cells with mutated RARα and was independent of differentiation. We confirmed that gene expression levels were inversely correlated with alterations in H3K27me3 histone marks localized at HOX gene promoters. Furthermore, data from chromatin immunoprecipitation followed by sequencing broaden a list of clustered HOX genes regulated by JMJD3 in PML-RARα-positive leukemic cells. Interestingly, the combination of GSK-J4 and all-trans retinoic acid (ATRA) significantly increased PML-RARα-positive cell apoptosis compared with ATRA treatment alone. This effect was also observed in ATRA-resistant NB4 clones, which may provide a new therapeutic opportunity for patients with acute promyelocytic leukemia (APL) resistant to current treatment. The results of our study reveal the mechanism of HOX gene expression regulation and contribute to our understanding of APL pathogenesis.

EZH2 Histone Methyltransferase and JMJD3 Histone Demethylase Implications in Prostate Cancer.

EZH2 Histone Methyltransferase and JMJD3 Histone Demethylase Implications in Prostate Cancer.

Calcitriol induces cell senescence of kidney cancer through JMJD3 mediated histone demethylation.

Calcitriol, also known as 1,25-dihydroxyvitamin D3 (1,25(OH)2VD3), is a biologically active form of vitamin D and has a wide range of anticancer activity against various cancer cell lines. However, the mechanism of calcitriol remains to be further studied. In this study, the biological effect and epigenetic regulation of calcitriol on kidney cancer cells were investigated. Calcitriol can significantly inhibit cell proliferation of kidney cancer cell lines 786-O (P<0.05). Calcitriol also induced cell apoptosis and senescence of 786-O and ACHN (P<0.05). Calcitriol can increase the expression of histone demethylase JMJD3 and cell senescence marker p16INK4A (P<0.05). Knockdown of JMJD3 decreased p16INK4A upregulation after calcitriol treatment (P<0.05), and also reduced calcitriol-induced cell senescence (P<0.05). This study reveals a new mechanism of anticancer activity of calcitriol by showing that histone demethylase JMJD3 induced by calcitriol increases p16INK4A expression and cell senescence. Therefore, these results provide new strategy for treatment and prevention of kidney cancer.

A Shot in the Dark Exposes More Trees in the Forest: Adding a Histone Demethylase (Jmjd3) and RIP-cre Neurons to the Coordination of Female Reproductive Function.

A Shot in the Dark Exposes More Trees in the Forest: Adding a Histone Demethylase (Jmjd3) and RIP-cre Neurons to the Coordination of Female Reproductive Function.