KDM4A-mediated histone demethylation of SLC7A11 inhibits cell ferroptosis in osteosarcoma.

Osteosarcoma (OS) is the most common type of bone tumor that seriously affects limb function and induces great pain in patients. Lung metastasis and chemotherapy resistance are two key issues leading to the poor prognosis of OS patients, therefore new treatment targets and strategies are urgently needed. In our study, we uncovered the role of histone demethylase KDM4A in regulating OS cell ferroptosis and tumor progression. KDM4A was significantly upregulated in OS specimens and high KDM4A expression was associated with poorer prognosis in OS patients. Our data indicated that targeting KDM4A significantly increased OS cell death, enhanced cisplatin response, and attenuated migration ability in vitro. KDM4A depletion dramatically inhibited tumor progression and lung metastasis of OS in vivo Further experiments confirmed that KDM4A knockdown promoted OS cell ferroptosis, a special non-apoptotic form of cell death. KDM4A regulates SLC7A11 transcription and OS cell ferroptosis by controlling H3K9me3 demethylation in the promoter region of SLC7A11. Our findings deepened the recognition of epigenetic regulatory mechanism in OS tumorigenesis, chemoresistance, and metastasis, suggesting that KDM4A activity may be a potential therapeutic target for future OS treatment.

Autochthonous tumors driven by Rb1 loss have an ongoing requirement for the RBP2 histone demethylase.

Inactivation of the retinoblastoma gene (RB1) product, pRB, is common in many human cancers. Targeting downstream effectors of pRB that are central to tumorigenesis is a promising strategy to block the growth of tumors harboring loss-of-function RB1 mutations. One such effector is retinoblastoma-binding protein 2 (RBP2, also called JARID1A or KDM5A), which encodes an H3K4 demethylase. Binding of pRB to RBP2 has been linked to the ability of pRB to promote senescence and differentiation. Importantly, genetic ablation of RBP2 is sufficient to phenocopy pRB's ability to induce these cellular changes in cell culture experiments. Moreover, germline Rbp2 deletion significantly impedes tumorigenesis in Rb1+/- mice. The value of RBP2 as a therapeutic target in cancer, however, hinges on whether loss of RBP2 could block the growth of established tumors as opposed to simply delaying their onset. Here we show that conditional, systemic ablation of RBP2 in tumor-bearing Rb1+/- mice is sufficient to slow tumor growth and significantly extend survival without causing obvious toxicity to the host. These findings show that established Rb1-null tumors require RBP2 for growth and further credential RBP2 as a therapeutic target in human cancers driven by RB1 inactivation.

Cancer cell niche factors secreted from cancer-associated fibroblast by loss of H3K27me3.

OBJECTIVE: Cancer-associated fibroblasts (CAFs), a major component of cancer stroma, can confer aggressive properties to cancer cells by secreting multiple factors. Their phenotypes are stably maintained, but the mechanisms are not fully understood. We aimed to show the critical role of epigenetic changes in CAFs in maintaining their tumour-promoting capacity and to show the validity of the epigenomic approach in identifying therapeutic targets from CAFs to starve cancer cells. DESIGN: Twelve pairs of primary gastric CAFs and their corresponding non-CAFs (NCAFs) were established from surgical specimens. Genome-wide DNA methylation and H3K27me3 analyses were conducted by BeadArray 450K and ChIP-on-Chip, respectively. Functions of potential a therapeutic target were analysed by inhibiting it, and prognostic impact was assessed in a database. RESULTS: CAFs had diverse and distinct DNA methylation and H3K27me3 patterns compared with NCAFs. Loss of H3K27me3, but not DNA methylation, in CAFs was enriched for genes involved in stem cell niche, cell growth, tissue development and stromal-epithelial interactions, such as WNT5A, GREM1, NOG and IGF2. Among these, we revealed that WNT5A, which had been considered to be derived from cancer cells, was highly expressed in cancer stromal fibroblasts, and was associated with poor prognosis. Inhibition of secreted WNT5A from CAFs suppressed cancer cell growth and migration. CONCLUSIONS: H3K27me3 plays a crucial role in defining tumour-promoting capacities of CAFs, and multiple stem cell niche factors were secreted from CAFs due to loss of H3K27me3. The validity of the epigenetic approach to uncover therapeutic targets for cancer-starving therapy was demonstrated.

Rescuing the aberrant sex development of H3K9 demethylase Jmjd1a-deficient mice by modulating H3K9 methylation balance.

Histone H3 lysine 9 (H3K9) methylation is a hallmark of heterochromatin. H3K9 demethylation is crucial in mouse sex determination; The H3K9 demethylase Jmjd1a deficiency leads to increased H3K9 methylation at the Sry locus in embryonic gonads, thereby compromising Sry expression and causing male-to-female sex reversal. We hypothesized that the H3K9 methylation level at the Sry locus is finely tuned by the balance in activities between the H3K9 demethylase Jmjd1a and an unidentified H3K9 methyltransferase to ensure correct Sry expression. Here we identified the GLP/G9a H3K9 methyltransferase complex as the enzyme catalyzing H3K9 methylation at the Sry locus. Based on this finding, we tried to rescue the sex-reversal phenotype of Jmjd1a-deficient mice by modulating GLP/G9a complex activity. A heterozygous GLP mutation rescued the sex-reversal phenotype of Jmjd1a-deficient mice by restoring Sry expression. The administration of a chemical inhibitor of GLP/G9a enzyme into Jmjd1a-deficient embryos also successfully rescued sex reversal. Our study not only reveals the molecular mechanism underlying the tuning of Sry expression but also provides proof on the principle of therapeutic strategies based on the pharmacological modulation of epigenetic balance.

IDH mutation impairs histone demethylation and results in a block to cell differentiation.

Recurrent mutations in isocitrate dehydrogenase 1 (IDH1) and IDH2 have been identified in gliomas, acute myeloid leukaemias (AML) and chondrosarcomas, and share a novel enzymatic property of producing 2-hydroxyglutarate (2HG) from α-ketoglutarate. Here we report that 2HG-producing IDH mutants can prevent the histone demethylation that is required for lineage-specific progenitor cells to differentiate into terminally differentiated cells. In tumour samples from glioma patients, IDH mutations were associated with a distinct gene expression profile enriched for genes expressed in neural progenitor cells, and this was associated with increased histone methylation. To test whether the ability of IDH mutants to promote histone methylation contributes to a block in cell differentiation in non-transformed cells, we tested the effect of neomorphic IDH mutants on adipocyte differentiation in vitro. Introduction of either mutant IDH or cell-permeable 2HG was associated with repression of the inducible expression of lineage-specific differentiation genes and a block to differentiation. This correlated with a significant increase in repressive histone methylation marks without observable changes in promoter DNA methylation. Gliomas were found to have elevated levels of similar histone repressive marks. Stable transfection of a 2HG-producing mutant IDH into immortalized astrocytes resulted in progressive accumulation of histone methylation. Of the marks examined, increased H3K9 methylation reproducibly preceded a rise in DNA methylation as cells were passaged in culture. Furthermore, we found that the 2HG-inhibitable H3K9 demethylase KDM4C was induced during adipocyte differentiation, and that RNA-interference suppression of KDM4C was sufficient to block differentiation. Together these data demonstrate that 2HG can inhibit histone demethylation and that inhibition of histone demethylation can be sufficient to block the differentiation of non-transformed cells.

Depletion of Jmjd1c impairs adipogenesis in murine 3T3-L1 cells.

Differentiation of adipocytes is a highly regulated process modulated by multiple transcriptional co-activators and co-repressors. JMJD1C belongs to the family of jumonji C (jmjC) domain-containing histone demethylases and was originally described as a ligand-dependent co-activator of thyroid hormone and androgen receptors. Here, we explored the potential role of Jmjd1c in white adipocyte differentiation. To investigate the relevance of Jmjd1c in adipogenesis, murine 3T3-L1 preadipocyte cells with transient knock-down of Jmjd1c (3T3_Jmjd1c) were generated. Depletion of Jmjd1c led to the formation of smaller lipid droplets, reduced accumulation of triglycerides and maintenance of a more fibroblast-like morphology after adipocyte differentiation. Concomitantly, insulin stimulated uptake of glucose and fatty acids was significantly reduced in 3T3_Jmjd1c adipocytes. In line with these observations we detected lower expression of key genes associated with lipid droplet formation (Plin1, Plin4, Cidea) and uptake of glucose and fatty acids (Glut4, Fatp1, Fatp4, Aqp7) respectively. Finally, we demonstrate that depletion of Jmjd1c interferes with mitotic clonal expansion (MCE), increases levels of H3K9me2 (dimethylation of lysine 9 of histone H3) at promotor regions of adipogenic transcription factors (C/EBPs and PPARγ) and leads to reduced induction of these key regulators. In conclusion, we have identified Jmjd1c as a modulator of adipogenesis. Our data suggest that Jmjd1c may participate in MCE and the activation of the adipogenic transcription program during the induction phase of adipocyte differentiation in 3T3-L1 cells.

Jmjd5 functions as a regulator of p53 signaling during mouse embryogenesis.

Genetic studies have shown that aberrant activation of p53 signaling leads to embryonic lethality. Maintenance of a fine balance of the p53 protein level is critical for normal development. Previously, we have reported that Jmjd5, a member of the Jumonji C (JmjC) family, regulates embryonic cell proliferation through the control of Cdkn1a expression. Since Cdkn1a is the representative p53-regulated gene, we have examined whether the expression of other p53 target genes is coincidentally upregulated with Cdkn1a in Jmjd5-deficient embryos. The expression of a subset of p53-regulated genes was increased in both Jmjd5 hypomorphic mouse embryonic fibroblasts (MEFs) and Jmjd5-deficient embryos at embryonic day 8.25 without the induced expression of Trp53. Intercrossing of Jmjd5-deficient mice with Trp53 knockout mice showed that the growth defect of Jmjd5 mutant cells was significantly recovered under a Trp53 null genetic background. Chromatin immunoprecipitation analysis in Jmjd5 hypomorphic MEFs indicated the increased recruitment of p53 at several p53 target gene loci, such as Cdkn1a, Pmaip1, and Mdm2. These results suggest that Jmjd5 is involved in the transcriptional regulation of a subset of p53-regulated genes, possibly through the control of p53 recruitment at the gene loci. In Jmjd5-deficient embryos, the enhanced recruitment of p53 might result in the abnormal activation of p53 signaling leading to embryonic lethality.

JMJD1C, a JmjC domain-containing protein, is required for long-term maintenance of male germ cells in mice.

JmjC domain-containing proteins are a class of enzymes responsible for histone demethylation. Previous studies revealed that the JmjC domain-containing protein KDM3A possesses intrinsic demethylase activity toward lysine 9 of histone H3 and plays essential roles in spermiogenesis. In contrast, the biological roles of JMJD1C, a KDM3A homolog in mice, are largely unknown. Here we present the crucial role of JMJD1C in male gametogenesis. Jmjd1c-deficient males became infertile due to the progressive reduction of germ cells after 3 mo of age. Importantly, Jmjd1c-deficient testes frequently contained abnormal tubules lacking developmentally immature germ cells. JMJD1C is most abundantly expressed in undifferentiated spermatogonia in mouse testis. The numbers of ZBTB16-positive spermatogonia and apoptotic germ cells in Jmjd1c-deficient testes decreased and increased in an age-dependent manner, respectively. Our studies demonstrated that JMJD1C contributes to the long-term maintenance of the male germ line.

Fbxl10/Kdm2b deficiency accelerates neural progenitor cell death and leads to exencephaly.

Histone methylation is the important transcription regulatory system that affects mammalian development and cell differentiation. Alterations in epigenetic gene regulation are associated with disease. Fbxl10 (F-box and leucine-rich repeat protein 10) is a JmjC domain-containing histone demethylase. Although Fbxl10 has been implicated in cell cycle regulation, cell death, senescence, and tumorigenesis, these functions are controversial and its physiological function is unclear. To determine the in vivo function of Fbxl10, in this study, we generated a homozygous mutation in the mouse Fbxl10 gene. About half of Fbxl10-deficient mice exhibit failure of neural tube closure, resulting in exencephaly and die shortly after birth. Fbxl10 deficiency also causes retinal coloboma and a curled tail with low penetrances. Fbxl10 mRNA is specifically expressed in the cranial neural folds at E8.5 embryos, and apoptosis increased in the neuroepithelium and mesenchyme of Fbxl10-deficient E9.5 embryos, consistent with neural tube defects found in Fbxl10-deficient mice. Depletion of Fbxl10 induced the increased expression of p19ARF, an inducer of apoptosis, in E8.5 embryos and mouse embryonic fibroblast cells. In addition, the number of mitotic neural progenitor cells is significantly increased in the mutant E14.5 brain. Our findings suggest that the Fbxl10 gene makes important contributions to embryonic neural development by regulating cell proliferation and cell death in mice.

Kdm2a deficiency in macrophages enhances thermogenesis to protect mice against HFD-induced obesity by enhancing H3K36me2 at the Pparg locus.

Kdm2a catalyzes H3K36me2 demethylation to play an intriguing epigenetic regulatory role in cell proliferation, differentiation, and apoptosis. Herein we found that myeloid-specific knockout of Kdm2a (LysM-Cre-Kdm2af/f, Kdm2a-/-) promoted macrophage M2 program by reprograming metabolic homeostasis through enhancing fatty acid uptake and lipolysis. Kdm2a-/- increased H3K36me2 levels at the Pparg locus along with augmented chromatin accessibility and Stat6 recruitment, which rendered macrophages with preferential M2 polarization. Therefore, the Kdm2a-/- mice were highly protected from high-fat diet (HFD)-induced obesity, insulin resistance, and hepatic steatosis, and featured by the reduced accumulation of adipose tissue macrophages and repressed chronic inflammation following HFD challenge. Particularly, Kdm2a-/- macrophages provided a microenvironment in favor of thermogenesis. Upon HFD or cold challenge, the Kdm2a-/- mice manifested higher capacity for inducing adipose browning and beiging to promote energy expenditure. Collectively, our findings demonstrate the importance of Kdm2a-mediated H3K36 demethylation in orchestrating macrophage polarization, providing novel insight that targeting Kdm2a in macrophages could be a viable therapeutic approach against obesity and insulin resistance.

JMJD3 deficiency alleviates lipopolysaccharide­induced acute lung injury by inhibiting alveolar epithelial ferroptosis in a Nrf2­dependent manner.

Acute respiratory distress syndrome (ARDS) is a deadly illness which presents with severe hypoxemia as well as diffuse alveolar damage. Jumonji domain­containing 3 (JMJD3), which belongs to the UTX/UTY JmjC­domain protein subfamily, is involved in infection, development, aging and immune disorders. However, the role of JMJD3 in acute lung injury (ALI) is still unclear. The present study explored the roles and potential mechanisms of JMJD3 in ALI. Alveolar epithelial cell­specific knockout of JMJD3 mice and A549 alveolar epithelial cells were used to investigate the function of JMJD3 in ALI. Lipopolysaccharide (LPS) was used to establish an in vivo and in vitro ALI model. The expression of JMJD3 in murine lung tissue and alveolar epithelial cells was detected. Pathological injury of lung tissue and alveolar epithelial cells was also investigated following inhibition of JMJD3. The results showed that JMJD3 expression was significantly increased in murine lung tissues and in A549 cells following LPS stimulation. JMJD3­deficient mice in alveolar epithelial cells exhibited alleviated lung pathological injury and ferroptosis following h stimulation. Mechanistically, it was found that JMJD3 knockout could increase the expression of nuclear factor erythroid­2­related factor­2 (Nrf2) in lung tissues challenged with h. However, Nrf2 overexpression by adenovirus could further enhance the anti­ferroptotic effect from JMJD3 silence in h­treated A549 cells. Taken together, the present study revealed that JMJD3 deficiency may relieve LPS­induced ALI by blocking alveolar epithelial ferroptosis in a Nrf2­dependent manner, which may serve as a novel therapeutic target against ALI.

Obesity and metabolic syndrome in histone demethylase JHDM2a-deficient mice.

Histone H3 lysine 9 (H3K9) methylation is a crucial epigenetic mark of heterochromatin formation and transcriptional silencing. Recent studies demonstrated that most covalent histone lysine modifications are reversible and the jumonji C (JmjC)-domain-containing proteins have been shown to possess such demethylase activities. However, there is little information available on the biological roles of histone lysine demethylation in intact animal model systems. JHDM2A (JmjC-domain-containing histone demethylase 2A, also known as JMJD1A) catalyses removal of H3K9 mono- and dimethylation through iron and alpha-ketoglutarate dependent oxidative reactions. Here, we demonstrate that JHDM2a also regulates metabolic genes related to energy homeostasis including anti-adipogenesis, regulation of fat storage, glucose transport and type 2 diabetes. Mice deficient in JHDM2a (JHDM2a-/-) develop adult onset obesity, hypertriglyceridemia, hypercholesterolemia, hyperinsulinemia and hyperleptinemia, which are hallmarks of metabolic syndrome. JHDM2a-/- mice furthermore exhibit fasted induced hypothermia indicating reduced energy expenditure and also have a higher respiratory quotient indicating less fat utilization for energy production. These observations may explain the obesity phenotype in these mice. Thus, H3K9 demethylase JHDM2a is a crucial regulator of genes involved in energy expenditure and fat storage, which suggests it is a previously unrecognized key regulator of obesity and metabolic syndrome.

JARID1a Ablation in the Liver Alters Systemic Metabolism and Adaptation to Feeding.

The liver is a key regulator of systemic energy homeostasis whose proper function is dependent on the circadian clock. Here, we show that livers deficient in the oscillator component JARID1a exhibit a dysregulation of genes involved in energy metabolism. Importantly, we find that mice that lack hepatic JARID1a have decreased lean body mass, decreased respiratory exchange ratios, faster production of ketones, and increased glucose production in response to fasting. Finally, we find that JARID1a loss compromises the response of the hepatic transcriptome to nutrient availability. In all, ablation of hepatic JARID1a disrupts the coordination of hepatic metabolic programs with whole-body consequences.

KDM2B promotes IL-6 production and inflammatory responses through Brg1-mediated chromatin remodeling.

IL-6 plays important and pleiotropic roles in infection and inflammatory diseases, and its production needs to be tightly regulated. However, the epigenetic mechanism underlying Il6 gene transcription remains to be fully elucidated. Here, we report that lysine-specific demethylase 2b (KDM2B), which demethylates H3K4me3 and H3K36me2, is required in macrophages and dendritic cells for the induction of IL-6 but not TNF-α, IL-1, and IFN-ß. Compared to wild-type mice, KDM2B-deficient mice were more resistant to endotoxin shock and colitis, with a less severe inflammatory pathogenesis phenotype and decreased IL-6 production in sera. KDM2B selectively bound the Il6 promoter but did not alter histone demethylation; instead, KDM2B interacted with Brahma-related gene 1 (Brg1), the core ATPase subunit of SWI/SNF chromatin remodeling complexes, to facilitate chromatin accessibility of the Il6 promoter. Furthermore, KDM2B directly recruited RNA Polymerase II to further initiate and promote Il6 transcription. Thus, our finding identifies a novel nonclassical function of KDM2B in gene-specific transcription initiation and enhancement of Il6 independent of its demethylase activity and adds new insight into the specific epigenetic modification mechanism of inflammatory immune responses.

JmjC domain-containing protein 8 (JMJD8) represses Ku70/Ku80 expression via attenuating AKT/NF-κB/COX-2 signaling.

Jumonji C (JmjC) domain-containing proteins have been shown to regulate cellular processes by hydroxylating or demethylating histone and non-histone targets. JMJD8 is a Jumonji C domain-containing protein localized in the lumen of the endoplasmic reticulum and was recently shown to be involved in endothelial differentiation and cellular inflammation response. However, other physiological functions of JMJD8 remain to be elucidated. In this research, we found that knockdown of JMJD8 in cancer cells significantly increased cell proliferation, and attenuated ionizing irradiation or etoposide treatment-induced DNA double-strand breaks (DSBs) level through enhancing the expression of Ku70 and Ku80 which are key participants in the non-homologous end-joining repair of DSBs. We also provided evidence to show that knockdown of JMJD8 up-regulated cyclooxygenase-2 (COX-2) expression which contributed to the enhanced expression of Ku70/Ku80 as shown by the results that pre-treatment of JMJD8 knockdown cells with COX-2 selective inhibitor NS-398 inhibited the induction of Ku70/Ku80. Furthermore, we identified that the up-regulation of COX-2 in JMJD8 knockdown cells was partially due to the increased activation of AKT/NF-κB signaling, and LY294002 (an inhibitor of the PI3K/AKT signaling pathway) repressed the induction of COX-2 and Ku70/Ku80. In conclusion, our research provided data to establish the role of JMJD8 in regulating tumor cell proliferation and their sensitivity to ionizing irradiation or chemo-therapy drug, and the AKT/NF-κB/COX-2 signaling mediated expression of Ku70/Ku80 was involved. The results of this research indicated that JMJD8 is a potential target for enhancing the efficacy of tumor radio- and chemo-therapies.

KDM2B in polycomb repressive complex 1.1 functions as a tumor suppressor in the initiation of T-cell leukemogenesis.

KDM2B together with RING1B, PCGF1, and BCOR or BCORL1 comprise polycomb repressive complex 1.1 (PRC1.1), a noncanonical PRC1 that catalyzes H2AK119ub1. It binds to nonmethylated CpG islands through its zinc finger-CxxC DNA binding domain and recruits the complex to target gene loci. Recent studies identified the loss of function mutations in the PRC1.1 gene, BCOR and BCORL1 in human T-cell acute lymphoblastic leukemia (T-ALL). We previously reported that Bcor insufficiency induces T-ALL in mice, supporting a tumor suppressor role for BCOR. However, the function of BCOR responsible for tumor suppression, either its corepressor function for BCL6 or that as a component of PRC1.1, remains unclear. We herein examined mice specifically lacking the zinc finger-CxxC domain of KDM2B in hematopoietic cells. Similar to Bcor-deficient mice, Kdm2b-deficient mice developed lethal T-ALL mostly in a NOTCH1-dependent manner. A chromatin immunoprecipitation sequence analysis of thymocytes revealed the binding of KDM2B at promoter regions, at which BCOR and EZH2 colocalized. KDM2B target genes markedly overlapped with those of NOTCH1 in human T-ALL cells, suggesting that noncanonical PRC1.1 antagonizes NOTCH1-mediated gene activation. KDM2B target genes were expressed at higher levels than the others and were marked with high levels of H2AK119ub1 and H3K4me3, but low levels of H3K27me3, suggesting that KDM2B target genes are transcriptionally active or primed for activation. These results indicate that PRC1.1 plays a key role in restricting excessive transcriptional activation by active NOTCH1, thereby acting as a tumor suppressor in the initiation of T-cell leukemogenesis.

Histone demethylase Kdm2a regulates germ cell genes and endogenous retroviruses in embryonic stem cells.

Aim: To investigate the function of Kdm2a in embryonic stem cells (ESCs). Materials & methods: Expression profile analysis after Kdm2a knockout. Analysis of Kdm2a, H3K4me3 and H3K27me3 ChIP-seq data in ESCs. qPCR analysis and ChIP-qPCR analysis of epigenetic changes after Kdm2a loss. Results:Kdm2a was dispensable for pluripotency maintenance in ESCs. Kdm2a genomic binding profile was positively correlated with that of H3K4me3, Zfx and Tet1. Kdm2a directly regulated germ cell genes in primordial germ cell-like cells. Kdm2a loss led to the reduced expression of endogenous retrovirus IAPEy and resulted in the gain of H3K36me2 and loss of H3K4me3 on IAPEy. Conclusion: Kdm2a regulates germ cell genes and endogenous retroviruses in ESCs possibly through demethylating H3K36me2 and influencing H3K4me3 deposition.

KDM2A/B lysine demethylases and their alternative isoforms in development and disease.

Aberrant levels of histone modifications lead to chromatin malfunctioning and consequently to various developmental defects and human diseases. Therefore, the proteins bearing the ability to modify histones have been extensively studied and the molecular mechanisms of their action are now fairly well understood. However, little attention has been paid to naturally occurring alternative isoforms of chromatin modifying proteins and to their biological roles. In this review, we focus on mammalian KDM2A and KDM2B, the only two lysine demethylases whose genes have been described to produce also an alternative isoform lacking the N-terminal demethylase domain. These short KDM2A/B-SF isoforms arise through alternative promoter usage and seem to play important roles in development and disease. We hypothesise about the biological significance of these alternative isoforms, which might represent a more common evolutionarily conserved regulatory mechanism.

Combined Loss of JMJD1A and JMJD1B Reveals Critical Roles for H3K9 Demethylation in the Maintenance of Embryonic Stem Cells and Early Embryogenesis.

Histone H3 lysine 9 (H3K9) methylation is unevenly distributed in mammalian chromosomes. However, the molecular mechanism controlling the uneven distribution and its biological significance remain to be elucidated. Here, we show that JMJD1A and JMJD1B preferentially target H3K9 demethylation of gene-dense regions of chromosomes, thereby establishing an H3K9 hypomethylation state in euchromatin. JMJD1A/JMJD1B-deficient embryos died soon after implantation accompanying epiblast cell death. Furthermore, combined loss of JMJD1A and JMJD1B caused perturbed expression of metabolic genes and rapid cell death in embryonic stem cells (ESCs). These results indicate that JMJD1A/JMJD1B-meditated H3K9 demethylation has critical roles for early embryogenesis and ESC maintenance. Finally, genetic rescue experiments clarified that H3K9 overmethylation by G9A was the cause of the cell death and perturbed gene expression of JMJD1A/JMJD1B-depleted ESCs. We summarized that JMJD1A and JMJD1B, in combination, ensure early embryogenesis and ESC viability by establishing the correct H3K9 methylated epigenome.

Myeloid Kdm6b deficiency results in advanced atherosclerosis.

BACKGROUND AND AIMS: Atherosclerosis is a lipid-driven chronic inflammatory disorder of the arteries, and monocytes and macrophages play a central role in this process. Within the atherosclerotic lesion, macrophages can scavenge modified lipids and become the so-called foam cells. We previously reported that the epigenetic enzyme Kdm6b (also known as Jmjd3) controls the pro-fibrotic transcriptional profile of peritoneal foam cells. Given the importance of these cells in atherosclerosis, we now studied the effect of myeloid Kdm6b on disease progression. METHODS: Bone marrow of myeloid Kdm6b deficient (Kdm6bdel) mice or wild type littermates (Kdm6bwt) was transplanted to lethally irradiated Ldlr-/- mice fed a high fat diet for 9 weeks to induce atherosclerosis. RESULTS: Lesion size was similar in Kdm6bwt and Kdm6bdel transplanted mice. However, lesions of Kdm6bdel mice contained more collagen and were more necrotic. Pathway analysis on peritoneal foam cells showed that the pathway involved in leukocyte chemotaxis was most significantly upregulated. Although macrophage and neutrophil content was similar after 9 weeks of high fat diet feeding, the relative increase in collagen content and necrosis revealed that atherosclerotic lesions in Kdm6bdel mice progress faster. CONCLUSION: Myeloid Kdm6b deficiency results in more advanced atherosclerosis.