Jmjd3 inhibits reprogramming by upregulating expression of INK4a/Arf and targeting PHF20 for ubiquitination

The occurrence and development of induced pluripotent stem cells

The ectopic expression of four transcription factors, Oct3/4, Sox2, Klf4, and c-Myc (OSKM), known as "Yamanaka factors," can reprogram or stimulate the production of induced pluripotent stem cells (iPSCs). Although OSKM is still the gold standard, there are multiple ways to reprogram cells into iPSCs. In recent years, significant progress has been made in improving the efficiency of this technology. Ten years after the first report was published, human pluripotent stem cells have gradually been applied in clinical settings, including disease modeling, cell therapy, new drug development, and cell derivation. Here, we provide a review of the discovery of iPSCs and their applications in disease and development.

X chromosome encoded histone demethylase UTX regulates mammalian axon regeneration via microRNA-124

Neurons in the mammalian central nervous system (CNS) gradually lose their intrinsic regeneration capacity during maturation mainly because of altered transcription profile. Recent studies have made great progress by identifying genes that can be manipulated to enhance CNS regeneration. However, as a complex process involving many genes and signaling networks, it is of great importance to deciphering the underlying neuronal chromatin and transcriptomic landscape coordinating CNS regeneration. Here we identify UTX, an X-chromosome associated gene encoding a histone demethylase, as a novel regulator of mammalian neural regeneration. We demonstrate that UTX acts as a repressor of spontaneous axon regeneration in the peripheral nerve system (PNS). In the CNS, either knocking out or pharmacological inhibiting UTX in retinal ganglion cells (RGCs) leads to significantly enhanced neuronal survival and optic nerve regeneration. RNA-seq profiling revealed that deleting UTX switches the RGC transcriptomics into a developmental-like state. Moreover, microRNA-124, one of the most abundant microRNAs in mature neurons, is identified as a downstream target of UTX and blocking endogenous microRNA124-5p results in robust optic nerve regeneration. These findings revealed a novel histone modification-microRNA epigenetic signaling network orchestrating transcriptomic landscape supporting CNS neural regeneration.

Direct cardiac reprogramming: A new technology for cardiac repair

Cardiovascular disease is one of the leading causes of morbidity and mortality worldwide, with myocardial infarctions being amongst the deadliest manifestations. Reduced blood flow to the heart can result in the death of cardiac tissue, leaving affected patients susceptible to further complications and recurrent disease. Further, contemporary management typically involves a pharmacopeia to manage the metabolic conditions contributing to atherosclerotic and hypertensive heart disease, rather than regeneration of the damaged myocardium. With modern healthcare extending lifespan, a larger demographic will be at risk for heart disease, driving the need for novel therapeutics that surpass those currently available in efficacy. Transdifferentiation and cellular reprogramming have been looked to as potential methods for the treatment of diseases throughout the body. Specifically targeting the fibrotic cells in cardiac scar tissue as a source to be reprogrammed into induced cardiomyocytes remains an appealing option. This review aims to highlight the history of and advances in cardiac reprogramming and describe its translational potential as a treatment for cardiovascular disease.

Context-Dependent Functions of KDM6 Lysine Demethylases in Physiology and Disease

Histone lysine methylation is a major epigenetic modification that participates in several cellular processes including gene regulation and chromatin structure. This mark can go awry in disease contexts such as cancer. Two decades ago, the discovery of histone demethylase enzymes thirteen years ago sheds light on the complexity of the regulation of this mark. Here we address the roles of lysine demethylases JMJD3 and UTX in physiological and disease contexts. The two demethylases play pivotal roles in many developmental and disease contexts via regulation of di- and trimethylation of lysine 27 on histone H3 (H3K27me2/3) in repressing gene expression programs. JMJD3 and UTX participate in several biochemical settings including methyltransferase and chromatin remodeling complexes. They have histone demethylase-dependent and -independent activities and a variety of context-specific interacting factors. The structure, amounts, and function of the demethylases can be altered in disease due to genetic alterations or aberrant gene regulation. Therefore, academic and industrial initiatives have targeted these enzymes using a number of small molecule compounds in therapeutic approaches. In this chapter, we will touch upon inhibitor formulations, their properties, and current efforts to test them in preclinical contexts to optimize their therapeutic outcomes. Demethylase inhibitors are currently used in targeted therapeutic approaches that might be particularly effective when used in conjunction with systemic approaches such as chemotherapy.

Transcriptional regulation of INK4/ARF locus by cis and trans mechanisms

9p21 locus is one of the most reproducible regions in genome-wide association studies (GWAS). The region harbors CDKN2A/B genes that code for p16INK4a, p15INK4b, and p14ARF proteins, and it also harbors a long gene desert adjacent to these genes. The polymorphisms that are associated with several diseases and cancers are present in these genes and the gene desert region. These proteins are critical cell cycle regulators whose transcriptional dysregulation is strongly linked with cellular regeneration, stemness, aging, and cancers. Given the importance of this locus, intense scientific efforts on understanding the regulation of these genes via promoter-driven mechanisms and recently, via the distal regulatory mechanism have provided major insights. In this review, we describe these mechanisms and propose the ways by which this locus can be targeted in pathologies and aging.

JMJD3 suppresses tumor progression in oral tongue squamous cell carcinoma patients receiving surgical resection

Background

Jumonji domain-containing-3 (JMJD3) is reported to be a histone H3 lysine 27 (H3K27) demethylase and a tumor suppressor gene. The present study designed to investigate the crucial role of JMJD3 in oral tongue squamous cell carcinoma (OTSCC) patients who received surgical resection.

Methods

We enrolled a total of 156 OTSCC patients receiving surgical resection, including 73 patients (47%) with high expression of JMJD3 and 83 patients (53%) harboring low expression of JMJD3. Two OTSCC cell lines, SAS and Cal 27, were used to explore the modulation of cancer. GSK-J4, a potent inhibitor of JMJD3, was used to treat the two OTSCC cell lines. The Chi-square test was performed to examine between-group differences in categorical variables; the Kaplan-Meier method was used to investigate survival outcome in univariate analysis, and the Cox regression model was used for multivariate analysis.

Results

The median follow-up period was 59.2 months and he five-year disease-free survival (DFS) and overall survival (OS) rates were 46.2% and 50.0%, respectively. Better five-year DFS (59% versus 35%) and five-year OS (63% versus 39%) were mentioned in patients with high expression of JMJD3 compared to those with low expression of JMJD3. High expression of JMJD3 was significantly associated with superior DFS and OS in the univariate and multivariate analyses. Following successful inhibition of JMJD3 by GSK-J4, western blotting analysis showed the decreased expression of Rb and p21.

Conclusion

Our study showed that high expression of JMJD3 is a good prognostic factor in OTSCC patients who underwent surgical resection.

Effects of GSK-J4 on JMJD3 Histone Demethylase in Mouse Prostate Cancer Xenografts

BACKGROUND/AIM

Histone methylation status is required to control gene expression. H3K27me3 is an epigenetic tri-methylation modification to histone H3 controlled by the demethylase JMJD3. JMJD3 is dysregulated in a wide range of cancers and has been shown to control the expression of a specific growth-modulatory gene signature, making it an interesting candidate to better understand prostate tumor progression in vivo. This study aimed to identify the impact of JMJD3 inhibition by its inhibitor, GSK4, on prostate tumor growth in vivo.

MATERIALS AND METHODS

Prostate cancer cell lines were implanted into Balb/c nude male mice. The effects of the selective JMJD3 inhibitor GSK-J4 on tumor growth were analyzed by bioluminescence assays and H3K27me3-regulated changes in gene expression were analyzed by ChIP-qPCR and RT-qPCR.

RESULTS

JMJD3 inhibition contributed to an increase in tumor growth in androgen-independent (AR-) xenografts and a decrease in androgen-dependent (AR+). GSK-J4 treatment modulated H3K27me3 enrichment on the gene panel in DU-145-luc xenografts while it had little effect on PC3-luc and no effect on LNCaP-luc. Effects of JMJD3 inhibition affected the panel gene expression.

CONCLUSION

JMJD3 has a differential effect in prostate tumor progression according to AR status. Our results suggest that JMJD3 is able to play a role independently of its demethylase function in androgen-independent prostate cancer. The effects of GSK-J4 on AR+ prostate xenografts led to a decrease in tumor growth.

MAP2K6 remodels chromatin and facilitates reprogramming by activating Gatad2b-phosphorylation dependent heterochromatin loosening

Somatic cell reprogramming is an ideal model for studying epigenetic regulation as it undergoes dramatic chromatin remodeling. However, a role for phosphorylation signaling in chromatin protein modifications for reprogramming remains unclear. Here, we identified mitogen-activated protein kinase kinase 6 (Mkk6) as a chromatin relaxer and found that it could significantly enhance reprogramming. The function of Mkk6 in heterochromatin loosening and reprogramming requires its kinase activity but does not depend on its best-known target, P38. We identified Gatad2b as a novel target of Mkk6 phosphorylation that acts downstream to elevate histone acetylation levels and loosen heterochromatin. As a result, Mkk6 over-expression facilitates binding of Sox2 and Klf4 to their targets and promotes pluripotency gene expression during reprogramming. Our studies not only reveal an Mkk phosphorylation mediated modulation of chromatin status in reprogramming, but also provide new rationales to further investigate and improve the cell fate determination processes.

Loss of SIRT1 inhibits hematopoietic stem cell aging and age-dependent mixed phenotype acute leukemia

Aging of hematopoietic stem cells (HSCs) is linked to various blood disorders and malignancies. SIRT1 has been implicated in healthy aging, but its role in HSC aging is poorly understood. Surprisingly, we found that Sirt1 knockout improved the maintenance of quiescence of aging HSCs and their functionality as well as mouse survival in serial bone marrow transplantation (BMT) recipients. The majority of secondary and tertiary BMT recipients of aging wild type donor cells developed B/myeloid mixed phenotype acute leukemia (MPAL), which was markedly inhibited by Sirt1 knockout. SIRT1 inhibition also reduced the growth and survival of human B/myeloid MPAL cells. Sirt1 knockout suppressed global gene activation in old HSCs, prominently the genes regulating protein synthesis and oxidative metabolism, which may involve multiple downstream transcriptional factors. Our results demonstrate an unexpected role of SIRT1 in promoting HSC aging and age-dependent MPAL and suggest SIRT1 may be a new therapeutic target for modulating functions of aging HSCs and treatment of MPAL.

Bone Morphogenetic Proteins Shape Treg Cells

The transforming growth factor-β (TGF-β) family includes cytokines controlling cell behavior, differentiation and homeostasis of various tissues including components of the immune system. Despite well recognized importance of TGF-β in controlling T cell functions, the immunomodulatory roles of many other members of the TGF-β cytokine family, especially bone morphogenetic proteins (BMPs), start to emerge. Bone Morphogenic Protein Receptor 1α (BMPR1α) is upregulated by activated effector and Foxp3+ regulatory CD4+ T cells (Treg cells) and modulates functions of both of these cell types. BMPR1α inhibits generation of proinflammatory Th17 cells and sustains peripheral Treg cells. This finding underscores the importance of the BMPs in controlling Treg cell plasticity and transition between Treg and Th cells. BMPR1α deficiency in in vitro induced and peripheral Treg cells led to upregulation of Kdm6b (Jmjd3) demethylase, an antagonist of polycomb repressive complex 2 (PRC2), and cell cycle inhibitor Cdkn1a (p21Cip1) promoting cell senescence. This indicates that BMPs and BMPR1α may represent regulatory modules shaping epigenetic landscape and controlling proinflammatory reprogramming of Th and Treg cells. Revealing functions of other BMP receptors and their crosstalk with receptors for TGF-β will contribute to our understanding of peripheral immunoregulation.

TRIM26-mediated degradation of nucleocapsid protein limits porcine reproductive and respiratory syndrome virus-2 infection

Porcine reproductive and respiratory syndrome (PRRS), caused by PRRSV, has ranked among the most economically important veterinary infectious diseases globally. Recently, tripartite motif (TRIMs) family members have arisen as novel restriction factors in antiviral immunity. Noteworthy, TRIM26 was reported as a binding partner of IRF3, TBK1, TAB1, and NEMO, yet its role in virus infection remains controversial. Herein, we showed that TRIM26 bound N protein by the C-terminal PRY/SPRY domain. Moreover, ectopic expression of TRIM26 impaired PRRSV replication and induced degradation of N protein. The anti-PRRSV activity was independent of the nuclear localization signal (NLS). Instead, deletion of the RING domain, or the PRY/SPRY portion, abrogated the antiviral function. Finally, siRNA depletion of TRIM26 resulted in enhanced production of viral RNA and virus yield in porcine alveolar macrophages (PAMs) after PRRSV infection. Overexpression of an RNAi-resistant TRIM26 rescue-plasmid led to the acquisition of PRRSV restriction in TRIM26-knockdown cells. Together, these data add TRIM26 as a potential target for drug design against PRRSV.

The ERα/KDM6B regulatory axis modulates osteogenic differentiation in human mesenchymal stem cells

Osteoporosis is a highly prevalent public health burden associated with an increased risk of bone fracture, particularly in aging women. Estrogen, an important medicinal component for the preventative and therapeutic treatment of postmenopausal osteoporosis, induces osteogenesis by activating the estrogen receptor signaling pathway and upregulating the expression of osteogenic genes, such as bone morphogenetic proteins (BMPs). The epigenetic regulation of estrogen-mediated osteogenesis, however, is still unclear. In this report, we found that estrogen significantly induced the expression of lysine-specific demethylase 6B (KDM6B) and that KDM6B depletion by shRNAs led to a significant reduction in the osteogenic potential of DMSCs. Mechanistically, upon estrogen stimulation, estrogen receptor-α (ERα) was recruited to the KDM6B promoter, directly enhancing KDM6B expression. Subsequently, KDM6B was recruited to the BMP2 and HOXC6 promoters, resulting in the removal of H3K27me3 marks and activating the transcription of BMP2 and HOXC6, the master genes of osteogenic differentiation. Furthermore, we found that estrogen enhanced DMSC osteogenesis during calvarial bone regeneration and that estrogen's pro-osteogenic effect was dependent on KDM6B in vivo. Taken together, our results demonstrate the vital role of the ERα/KDM6B regulatory axis in the epigenetic regulation of the estrogen-dependent osteogenic response.

Competitive binding of E3 ligases TRIM26 and WWP2 controls SOX2 in glioblastoma

The pluripotency transcription factor SOX2 is essential for the maintenance of glioblastoma stem cells (GSC), which are thought to underlie tumor growth, treatment resistance, and recurrence. To understand how SOX2 is regulated in GSCs, we utilized a proteomic approach and identified the E3 ubiquitin ligase TRIM26 as a direct SOX2-interacting protein. Unexpectedly, we found TRIM26 depletion decreased SOX2 protein levels and increased SOX2 polyubiquitination in patient-derived GSCs, suggesting TRIM26 promotes SOX2 protein stability. Accordingly, TRIM26 knockdown disrupted the SOX2 gene network and inhibited both self-renewal capacity as well as in vivo tumorigenicity in multiple GSC lines. Mechanistically, we found TRIM26, via its C-terminal PRYSPRY domain, but independent of its RING domain, stabilizes SOX2 protein by directly inhibiting the interaction of SOX2 with WWP2, which we identify as a bona fide SOX2 E3 ligase in GSCs. Our work identifies E3 ligase competition as a critical mechanism of SOX2 regulation, with functional consequences for GSC identity and maintenance.

SOX2 is required for the maintenance of glioblastoma stem cells (GSCs). Here the authors identify that the RING family E3 ubiquitin ligase TRIM26 promotes SOX2 stability in a non-canonical ligase-independent manner and thus, increases the tumorigenicity of GSCs.

Bone Morphogenic Proteins Are Immunoregulatory Cytokines Controlling FOXP3+ Treg Cells

Bone morphogenic proteins (BMPs) are members of the transforming growth factor β (TGF-β) cytokine family promoting differentiation, homeostasis, and self-renewal of multiple tissues. We show that signaling through the bone morphogenic protein receptor 1α (BMPR1α) sustains expression of FOXP3 in T_reg cells in peripheral lymphoid tissues. BMPR1α signaling promotes molecular circuits supporting acquisition and preservation of T_reg cell phenotype and inhibiting differentiation of pro-inflammatory effector Th1/Th17 CD4⁺ T cell. Mechanistically, increased expression of KDM6B (JMJD3) histone demethylase, an antagonist of the polycomb repressive complex 2, underlies lineage-specific changes of T cell phenotypes associated with abrogation of BMPR1α signaling. These results reveal that BMPs are immunoregulatory cytokines mediating maturation and stability of peripheral FOXP3⁺ regulatory T cells (T_reg cells) and controlling generation of iT_reg cells. Thus, we establish that BMPs, a large cytokine family, are an essential link between stromal tissues and the adaptive immune system involved in sustaining tissue homeostasis by promoting immunological tolerance.

Targeting WD Repeat-Containing Protein 5 (WDR5): A Medicinal Chemistry Perspective

WD repeat-containing protein 5 (WDR5) is a member of the WD40 protein family, and it is widely involved in various biological activities and not limited to epigenetic regulation in vivo. WDR5 is also involved in the initiation and development of many diseases and plays a key role in these diseases. Since WDR5 was discovered, it has been suggested as a potential disease treatment target, and a large number of inhibitors targeting WDR5 have been discovered. In this review, we discussed the development of inhibitors targeting WDR5 over the years, and the biological mechanisms of these inhibitors based on previous mechanistic studies were explored. Finally, we describe the development potential of inhibitors targeting WDR5 and prospects for further applications.

JMJD3: a critical epigenetic regulator in stem cell fate

The Jumonji domain-containing protein-3 (JMJD3) is a histone demethylase that regulates the trimethylation of histone H3 on lysine 27 (H3K27me3). H3K27me3 is an important epigenetic event associated with transcriptional silencing. JMJD3 has been studied extensively in immune diseases, cancer, and tumor development. There is a comprehensive epigenetic transformation during the transition of embryonic stem cells (ESCs) into specialized cells or the reprogramming of somatic cells to induced pluripotent stem cells (iPSCs). Recent studies have illustrated that JMJD3 plays a major role in cell fate determination of pluripotent and multipotent stem cells (MSCs). JMJD3 has been found to enhance self-renewal ability and reduce the differentiation capacity of ESCs and MSCs. In this review, we will focus on the recent advances of JMJD3 function in stem cell fate.

PHF20 inhibition promotes apoptosis and cisplatin chemosensitivity via the OCT4‑p‑STAT3‑MCL1 signaling pathway in hypopharyngeal squamous cell carcinoma

Cisplatin is a widely used platinum‑based chemotherapeutic agent for hypopharyngeal squamous cell carcinoma (HSCC). However, resistance to cisplatin limits its use for the treatment of HSCC, and the underlying molecular mechanism requires further investigation. The present study performed functional assays to determine whether the expression of plant homeodomain finger protein 20 (PHF20) may be involved in the apoptosis and cisplatin resistance of HSCC. The expression levels of PHF20 were higher in cisplatin‑resistant HSCC cells compared with those in cisplatin‑sensitive cells. The inhibition of PHF20 suppressed cell viability but did not affect the migratory and invasive abilities of HSCC cells compared with those of negative control‑transfected cells. Furthermore, PHF20 inhibition reduced cell viability by enhancing apoptosis compared with those in the control cells in vitro. Notably, the inhibition of PHF20 sensitized HSCC cells to cisplatin, thus increasing apoptosis via the signal transducer and activator of transcription 3 (STAT3)‑myeloid cell leukemia‑1 (MCL1) pathway. Octamer‑binding transcription factor 4 (OCT4) overexpression restored phosphorylated STAT3‑MCL1‑mediated apoptosis induced by PHF20 inhibition. In vivo experiments confirmed that PHF20 silencing induced tumor growth and increased apoptosis in HSCC cells compared with those in the control cells. Thus, PHF20 inhibition may promote apoptosis and improve cisplatin chemosensitivity via the OCT4‑p‑STAT3‑MCL1 signaling pathway in HSCC.

Expression pattern of histone lysine-specific demethylase 6B in gastric cancer

Over the last few decades, predictive markers for the prognosis of gastric cancer have not been extensively investigated. The present study aimed to evaluate the expression profile of histone demethylase lysine (K)-specific demethylase 6B (KDM6B) in gastric cancer and healthy control tissues, as well as its value in prognosis prediction as a clinical marker. Within the framework of these criteria, the diagnostic role of KMD6B for gastric cancer was investigated, which may provide insights into novel treatment targets. Immunohistochemistry was applied to detect KMD6B expression in 100 gastric cancer tissues and matching para-cancerous tissues to analyze the association between KMD6B expression and clinicopathological features. Based on the follow-up data, the value of KMD6B in prognosis assessment was further explored. The role of KMD6B in gastric cancer cell proliferation, cell cycle distribution and the expression of cell cycle-associated proteins was investigated by inhibiting KMD6B activity using the specific inhibitor GSK J4. KMD6B was mostly distributed in cytoplasm and nucleus in gastric cancer tissue. The expression level was significantly higher in cancer tissues compared with that in the corresponding non-cancerous tissues. The expression of KMD6B was significantly associated with sex, lymph node and distant metastasis status and clinical stage (P<0.05). Cell proliferation was significantly decreased with the inhibition of KMD6B activity, and the cell cycle in HGC27 cells was arrested in the G₂/M phase after being treated with GSK J4 for 24 h. The expression of cyclin B and Cdc2 were significantly decreased, while p21 was upregulated. It was concluded that the dysregulated expression of KMD6B is associated with the malignant progression of gastric cancer and could be a potential marker for prognosis. Blocking the demethylase activity of KMD6B induced G₂/M arrest and inhibited the proliferation of gastric cancer cells, suggesting that KMD6B is a potential novel therapeutic target for gastric cancer.

Unlocking the Recovery Potential: JMJD3 Inhibition-Mediated SAPK/JNK Signaling Inactivation Supports Endogenous Oligodendrocyte-Lineage Commitment Post Mammalian Spinal Cord Injury

Spinal cord injury (SCI) induced catastrophic neurological disability is often incurable at present. The injury triggered immediately oligodendrocytes loss and overwhelming demyelination are regarded as an insurmountable barrier to SCI recovery. To date, effective strategy to promote the endogenous oligodendrocytes replacement post SCI remains elusive. Epigenetic modifications are emerging as critical molecular switches of gene expression in CNS. However, the epigenetic mechanisms underlying oligodendrogenesis post SCI yet to be discovered. In this study, we report that H3K27me3 demethylase JMJD3 exists as a pivotal epigenetic regulator which manipulates the endogenous oligodendrogenesis post SCI. We found that JMJD3 inhibition promotes the oligodendrocyte linage commitment of neural stem/progenitor cells (NPCs) in vitro and in vivo. Moreover, we demonstrated that JMJD3 inhibition mediated SAPK/JNK signaling inactivation is functionally necessary for endogenous oligodendrocyte-lineage commitment post SCI. Our results also suggested that JMJD3 is downstream of SAPK/JNK pathway, and capable of translates SCI induced SAPK/JNK signaling into epigenetic codes readable by spinal cord endogenous NPCs. Taken together, our findings provide novel evidence of JMJD3 mediated oligodendrocyte-lineage commitment orchestration post SCI, which would be a potential epigenetic approach to induce the mature mammalian endogenous recovery.

KDM6B (JMJD3) and its dual role in cancer

Epigenetic modifications play a fundamental role in the regulation of gene expression and cell fate. During the development of cancer, epigenetic modifications appear that favor cell proliferation and migration, but at the same time prevent differentiation and apoptosis, among other processes. KDM6B is a histone demethylase that specifically removes methyl groups from H3K27me3, thus allowing re-expression of its target genes. It is currently known that KDM6B can act as both a tumor suppressor and an oncogene depending on the cellular context. Therefore, in this work we summarize the current knowledge of the role that KDM6B plays in different oncological contexts, and we try to orient it towards its clinical application.

The Functions of the Demethylase JMJD3 in Cancer

Cancer is a major cause of death worldwide. Epigenetic changes in response to external (diet, sports activities, etc.) and internal events are increasingly implicated in tumor initiation and progression. In this review, we focused on post-translational changes in histones and, more particularly, the tri methylation of lysine from histone 3 (H3K27me3) mark, a repressive epigenetic mark often under- or overexpressed in a wide range of cancers. Two actors regulate H3K27 methylation: Jumonji Domain-Containing Protein 3 demethylase (JMJD3) and Enhancer of zeste homolog 2 (EZH2) methyltransferase. A number of studies have highlighted the deregulation of these actors, which is why this scientific review will focus on the role of JMJD3 and, consequently, H3K27me3 in cancer development. Data on JMJD3’s involvement in cancer are classified by cancer type: nervous system, prostate, blood, colorectal, breast, lung, liver, ovarian, and gastric cancers.

Histone H3K27 methyltransferase EZH2 and demethylase JMJD3 regulate hepatic stellate cells activation and liver fibrosis

Rationale: As the central hallmark of liver fibrosis, transdifferentiation of hepatic stellate cells (HSCs), the predominant contributor to fibrogenic hepatic myofibroblast responsible for extracellular matrix (ECM) deposition, is characterized with transcriptional and epigenetic remodeling. We aimed to characterize the roles of H3K27 methyltransferase EZH2 and demethylase JMJD3 and identify their effective pathways and novel target genes in HSCs activation and liver fibrosis.

Methods: In primary HSCs, we analyzed effects of pharmacological inhibitions and genetic manipulations of EZH2 and JMJD3 on HSCs activation. In HSCs cell lines, we evaluated effects of EZH2 inhibition by DZNep on proliferation, cell cycling, senescence and apoptosis. In CCl₄ and BDL murine models of liver fibrosis, we assessed in vivo effects of DZNep administration and Ezh2 silencing. We profiled rat primary HSCs transcriptomes with RNA-seq, screened the pathways and genes associated with DZNep treatment, analyzed EZH2 and JMJD3 regulation towards target genes by ChIP-qPCR.

Results: EZH2 inhibition by DZNep resulted in retarded growth, lowered cell viability, cell cycle arrest in S and G2 phases, strengthened senescence, and enhanced apoptosis of HSCs, decreased hepatic collagen deposition and rescued the elevated serum ALT and AST activities of diseased mice, and downregulated cellular and hepatic expressions of H3K27me3, EZH2, α-SMA and COL1A. Ezh2 silencing by RNA interference in vitro and in vivo showed similar effects. JMJD3 inhibition by GSK-J4 and overexpression of wild-type but not mutant Jmjd3 enhanced or repressed HSCs activation respectively. EZH2 inhibition by DZNep transcriptionally inactivated TGF-β1 pathway, cell cycle pathways and vast ECM components in primary HSCs. EZH2 inhibition decreased H3K27me3 recruitment at target genes encoding TGF-β1 pseudoreceptor BAMBI, anti-inflammatory cytokine IL10 and cell cycle regulators CDKN1A, GADD45A and GADD45B, and increased their expressions, while Jmjd3 overexpression manifested alike effects.

Conclusions: EZH2 and JMJD3 antagonistically modulate HSCs activation. The therapeutic effects of DZNep as epigenetic drug in liver fibrosis are associated with the regulation of EZH2 towards direct target genes encoding TGF-β1 pseudoreceptor BAMBI, anti-inflammatory cytokine IL10 and cell cycle regulators CDKN1A, GADD45A and GADD45B, which are also regulated by JMJD3. Our present study provides new mechanistic insight into the epigenetic modulation of EZH2 and JMJD3 in HSCs biology and hepatic fibrogenesis.

Going up the hill: chromatin-based barriers to epigenetic reprogramming

The establishment and maintenance of cellular identity are crucial during development and tissue homeostasis. Epigenetic mechanisms based largely on DNA methylation and histone modifications serve to reinforce and safeguard differentiated cell states. Somatic cell nuclear transfer (SCNT) or transcription factors such as Oct4, Sox2, Klf4, c-MYC (OSKM) can erase somatic cell identity and reprogram the cells to a pluripotent state. In doing so, reprogramming must reset the chromatin landscape, silence somatic-specific gene expression programs, and, in their place, activate the pluripotency network. In this viewpoint, we consider the major chromatin-based barriers for reprogramming of somatic cells to pluripotency. Among these, repressive chromatin modifications such as DNA methylation, H3K9 methylation, variant histone deposition, and histone deacetylation generally block the activation of pluripotency genes. In contrast, active transcription-associated chromatin marks such as DOT1L-catalyzed H3K79 methylation, FACT-mediated histone turnover, active enhancer SUMOylation, and EP300/CBP bromodomain-mediated interactions act to maintain somatic-specific gene expression programs. We highlight how genetic or chemical inhibition of both types of barriers can enhance the kinetics and/or efficiency of reprogramming. Understanding the mechanisms by which these barriers function provides insight into how chromatin marks help maintain cell identity.

Histone demethylase UTX/KDM6A enhances tumor immune cell recruitment, promotes differentiation and suppresses medulloblastoma

The deregulation of epigenetic pathways has been implicated as a critical step in tumorigenesis including in childhood brain tumor medulloblastoma. The H3K27me3 demethylase UTX/KDM6A plays important roles in development and is frequently mutated in various types of cancer. However, how UTX regulates tumor development remains largely unclear. Here, we report the generation of a UTX-deleted mouse model of SHH medulloblastoma that demonstrates the tumor suppressor functions of UTX, which could be antagonized by the deletion of another H3K27me3 demethylase JMJD3/KDM6B. Intriguingly, UTX deletion in cancerous cerebellar granule neuron precursors (CGNPs) resulted in the impaired recruitment of host CD8⁺ T cells to the tumor microenvironment through a non-cell autonomous mechanism. In both mouse medulloblastoma models and in human medulloblastoma cells, we showed that UTX activates Th1-type chemokines, which are responsible for T cell migration. Surprisingly, our results showed that the depletion of cytotoxic CD8⁺ T cells did not affect mouse medulloblastoma growth. Nevertheless, the UTX/chemokine/T cell recruitment pathway we identified may be applied to many other cancers and may be important for improving cancer immunotherapy. In addition, UTX is required for the expression of NeuroD2 in precancerous progenitors, which encodes a potent proneural transcription factor. Overexpression of NEUROD2 in CGNPs decreased cell proliferation and increased neuron differentiation. We showed that UTX deletion led to impaired neural differentiation, which could coordinate with active SHH signaling to accelerate medulloblastoma development. Thus, UTX regulates both cell-intrinsic oncogenic processes and the tumor microenvironment in medulloblastoma. Our study provides insights into both medulloblastoma development and context dependent functions of UTX in tumorigenesis.

Combination of lysine-specific demethylase 6A (KDM6A) and mismatch repair (MMR) status is a potential prognostic factor in colorectal cancer

PURPOSE

To evaluate the relationship between the DNA mismatch repair (MMR) status and histone lysine-specific demethylase 6A (KDM6A) on the prognosis of colorectal cancer (CRC).

METHODS

About 594 patients with CRC from The Cancer Genome Atlas (TCGA) were enrolled in this retrospective study. Subsequently, a series of different classification tests for MMR status, cancer types, and target gene expression was conducted.

RESULTS

After filtering out the KDMs group of genes, we selected KDM6A as the target gene. A significant difference in the performance of KDM6A in tumor and normal tissues were confirmed. Our results showed a lower KDM6A expression, lower KDM6A exon expression, and higher KDM6A DNA methylation than their corresponding normal tissues in colon adenocarcinoma (COAD). Notably, the main MMR genes were highly expressed in tumor tissues than normal tissues both in COAD and rectum adenocarcinoma (READ). Moreover, proficient DNA mismatch repair (pMMR) was found to be an important poor prognostic factor in COAD (p = 0.0064) and the low KDM6A expression was an important factor for poor prognosis in READ (p = 0.0217). Based on these results, we consequently relate MMR status with KDM6A expression in predicting the prognosis of patients with CRC. Moreover, patients with pMMR exhibited a low KDM6A expression in COAD (p = 0.0250). Samples were divided into two groups based on the KDM6A expression. Interestingly, the group with low KDM6A expression showed no difference between pMMR and deficient DNA mismatch repair (dMMR) in prognosis, whereas the group with high KDM6A expression was closely related to MMR status in OS (p = 0.0082). Besides, COAD patients with high KDM6A expression and pMMR status had poor OS (p = 0.0082).

CONCLUSIONS

The KDM6A/MMR classification-based subtypes of low KDM6A expression/READ, high KDM6A expression/pMMR, and COAD/pMMR were associated with poor prognosis. This classification can be a novel prognostic approach in CRC.

Epigenetic regulation of neural lineage elaboration: Implications for therapeutic reprogramming

The vulnerability of the mammalian brain is mainly due to its limited ability to generate new neurons once fully matured. Direct conversion of non-neuronal cells to neurons opens up a new avenue for therapeutic intervention and has made great strides also for in vivo applications in the injured brain. These great achievements raise the issue of adequate identity and chromatin hallmarks of the induced neurons. This may be particularly important, as aberrant epigenetic settings may reveal their adverse effects only in certain brain activity states. Therefore, we review here the knowledge about epigenetic memory and partially resetting of chromatin hallmarks from other reprogramming fields, before moving to the knowledge in direct neuronal reprogramming, which is still limited. Most importantly, novel tools are available now to manipulate specific epigenetic marks at specific sites of the genome. Applying these will eventually allow erasing aberrant epigenetic memory and paving the way towards new therapeutic approaches for brain repair.

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

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.

JMJD3 acts in tandem with KLF4 to facilitate reprogramming to pluripotency

The interplay between the Yamanaka factors (OCT4, SOX2, KLF4 and c-MYC) and transcriptional/epigenetic co-regulators in somatic cell reprogramming is incompletely understood. Here, we demonstrate that the histone H3 lysine 27 trimethylation (H3K27me3) demethylase JMJD3 plays conflicting roles in mouse reprogramming. On one side, JMJD3 induces the pro-senescence factor Ink4a and degrades the pluripotency regulator PHF20 in a reprogramming factor-independent manner. On the other side, JMJD3 is specifically recruited by KLF4 to reduce H3K27me3 at both enhancers and promoters of epithelial and pluripotency genes. JMJD3 also promotes enhancer-promoter looping through the cohesin loading factor NIPBL and ultimately transcriptional elongation. This competition of forces can be shifted towards improved reprogramming by using early passage fibroblasts or boosting JMJD3’s catalytic activity with vitamin C. Our work, thus, establishes a multifaceted role for JMJD3, placing it as a key partner of KLF4 and a scaffold that assists chromatin interactions and activates gene transcription.

Previous work suggested that histone demethylase JMJD3 is detrimental to somatic cell reprogramming. Here, the authors show that while JMJD3 has a context-independent detrimental effect on early stages of reprogramming, during late stages it activates epithelial and pluripotency genes together with Klf4.

PHF20 Promotes Glioblastoma Cell Malignancies Through a WISP1/BGN-Dependent Pathway

Glioblastoma (GBM) stem cells are resistant to cancer therapy, and therefore responsible for tumor progression and recurrence after conventional therapy. However, the molecular mechanisms driving the maintenance of stemness and dedifferentiation are poorly understood. In this study, we identified plant homeodomain finger-containing protein 20 (PHF20) as a crucial epigenetic regulator for sustaining the stem cell-like phenotype of GBM. It is highly expressed in GBM and tightly associated with high levels of aggressiveness of tumors and potential poor prognosis in GBM patients. Knockout of PHF20 inhibits GBM cell proliferation, as well as its invasiveness and stem cell-like traits. Mechanistically, PHF20 interacts with WDR5 and binds to the promoter regions of WISP1 for its expression. Subsequently, WISP1 and BGN act in concert to regulate the degradation of β-Catenin. Our findings have identified PHF20 as a key driver of GBM malignant behaviors, and provided a potential target for developing prognosis and therapy.

Updates and challenges of axon regeneration in the mammalian central nervous system

Axon regeneration in the mammalian central nervous system (CNS) has been a long-standing and highly challenging issue. Successful CNS axon regeneration will benefit many human diseases involving axonal damage, such as spinal cord injury, traumatic brain injury, glaucoma, and neurodegenerative diseases. The current consensus is that the diminished intrinsic regenerative ability in mature CNS neurons and the presence of extrinsic inhibitors blocking axon regrowth are two major barriers for axon regeneration. During the past decade, studies targeting the intrinsic axon growth ability via regulation of gene transcription have produced very promising results in optic nerve and/or spinal cord regeneration. Manipulations of various signaling pathways or the nuclear transcription factors directly have been shown to sufficiently drive CNS axon regrowth. Converging evidence reveals that some pro-regenerative transcriptomic states, which are commonly accomplished by more comprehensive epigenetic regulations, exist to orchestrate the complex tasks of injury sensing and axon regeneration. Moreover, genetic reprogramming achieved via transcriptome and epigenome modifications provides novel mechanisms for enhancing axon regeneration. Recent studies also highlighted the important roles of remodeling neuronal cytoskeleton in overcoming the extrinsic inhibitory cues. However, our knowledge about the cellular and molecular mechanisms by which neurons regulate their intrinsic axon regeneration ability and response to extrinsic inhibitory cues is still fragmented. Here, we provide an update about recent research progress in axon regeneration and discuss major remaining challenges for long-distance axon regeneration and the subsequent functional recovery.

Interplay of m6A and H3K27 trimethylation restrains inflammation during bacterial infection

While N 6-methyladenosine (m6A) is the most prevalent modification of eukaryotic messenger RNA (mRNA) involved in various cellular responses, its role in modulating bacteria-induced inflammatory response remains elusive. Here, we showed that loss of the m6A reader YTH-domain family 2 (YTHDF2) promoted demethylation of histone H3 lysine-27 trimethylation (H3K27me3), which led to enhanced production of proinflammatory cytokines and facilitated the deposition of m6A cotranscriptionally. Mechanistically, the mRNA of lysine demethylase 6B (KDM6B) was m6A-modified and its decay mediated by YTHDF2. YTHDF2 deficiency stabilized KDM6B to promote H3K27me3 demethylation of multiple proinflammatory cytokines and subsequently enhanced their transcription. Furthermore, we identified H3K27me3 as a barrier for m6A modification during transcription. KDM6B recruits the m6A methyltransferase complex to facilitate the methylation of m6A in transcribing mRNA by removing adjacent H3K27me3 barriers. These results revealed cross-talk between m6A and H3K27me3 during bacterial infection, which has broader implications for deciphering epitranscriptomics in immune homeostasis.

Cancer Stem Cell-Inducing Media Activates Senescence Reprogramming in Fibroblasts

Cellular senescence is a tumor-suppressive mechanism blocking cell proliferation in response to stress. However, recent evidence suggests that senescent tumor cells can re-enter the cell cycle to become cancer stem cells, leading to relapse after cancer chemotherapy treatment. Understanding how the senescence reprogramming process is a precursor to cancer stem cell formation is of great medical importance. To study the interplay between senescence, stemness, and cancer, we applied a stem cell medium (SCM) to human embryonic fibroblasts (MRC5 and WI-38) and cancer cell lines (A549 and 293T). MRC5 and WI-38 cells treated with SCM showed symptoms of oxidative stress and became senescent. Transcriptome analysis over a time course of SCM-induced senescence, revealed a developmental process overlapping with the upregulation of genes for growth arrest and the senescence-associated secretory phenotype (SASP). We demonstrate that histone demethylases jumonji domain-containing protein D3 (Jmjd3) and ubiquitously transcribed tetratricopeptide repeat, X chromosome (Utx), which operate by remodeling chromatin structure, are implicated in the senescence reprogramming process to block stem cell formation in fibroblasts. In contrast, A549 and 293T cells cultured in SCM were converted to cancer stem cells that displayed the phenotype of senescence uncoupled from growth arrest. The direct overexpression of DNA methyltransferases (Dnmt1 and Dnmt3A), ten-eleven translocation methylcytosine dioxygenases (Tet1 and Tet3), Jmjd3, and Utx proteins could activate senescence-associated beta-galactosidase (SA-β-gal) activity in 293T cells, suggesting that epigenetic alteration and chromatin remodeling factors trigger the senescence response. Overall, our study suggests that chromatin machinery controlling senescence reprogramming is significant in cancer stem cell formation.

Yin Yang 1 is required for PHD finger protein 20-mediated myogenic differentiation in vitro and in vivo

The development of skeletal muscle requires progression of a highly ordered cascade of events comprising myogenic lineage commitment, myoblast proliferation, and terminal differentiation. The process of myogenesis is controlled by several myogenic transcription factors that act as terminal effectors of signaling cascades and produce appropriate developmental stage-specific transcripts. PHD finger protein 20 (PHF20) is a multidomain protein and subunit of a lysine acetyltransferase complex that acetylates histone H4 and p53, but its function is unclear. Notably, it has been reported that PHF20 knockout mice die shortly after birth and display a wide variety of phenotypes within the skeletal and hematopoietic systems. Therefore, the putative role of PHF20 in myogenic differentiation was further investigated. In the present study, we found that protein and mRNA expression levels of PHF20 were decreased during myogenic differentiation in C₂C₁₂ cells. At the same time, Yin Yang 1 (YY1) was also decreased during myogenic differentiation. PHF20 overexpression increased YY1 expression during myogenic differentiation, together with a delay in MyoD expression. PHF20 expression enhanced the transcriptional activity of YY1 while shRNA-mediated depletion of PHF20 resulted in the reduction of YY1 promoter activity in C₂C₁₂ cells. In addition, PHF20 directly bounds to the YY1 promoter in C₂C₁₂ cells. In a similar manner, YY1 expression was elevated while myosin heavy chain expression was decreased in PHF20 transgenic (TG) mice. Histological analysis revealed abnormalities in the shape and length of muscles in PHF20-TG mice. Furthermore, PHF20-TG muscles slowly regenerated after cardiotoxin injection, indicating that PHF20 affected muscle differentiation and regeneration after injury in vivo. Taken together, these results suggested that PHF20 plays an important role in myogenic differentiation by regulating YY1.

The crosstalk between cellular reprogramming and senescence in aging and regeneration

Aging is associated with diminished regenerative capacity and increased risk of chronic diseases. There is now compelling evidence suggests that aging process is reversible. Besides metabolic modification and systematic factors, both senescence elimination and cellular reprogramming showed beneficial effects on tissue regeneration and rejuvenation. Here we review recent studies on the interplay between cellular senescence and reprogramming. We discuss how both strategies could impact aging process and the possibility of combine them for more efficient regeneration and rejuvenation.

Enhancer-mediated enrichment of interacting JMJD3-DDX21 to ENPP2 locus prevents R-loop formation and promotes transcription

ENPP2, which encodes for the enzyme autotaxin (ATX), is overexpressed during chronic inflammatory diseases and various cancers. However, the molecular mechanism involved in the ENPP2 transcription remains elusive. Here, in HEK 293T cells, we demonstrated that lipopolysaccharide (LPS) increased the transcription process at ENPP2 locus through a NF-кB pathway and a reduction of H3K27me3 level, a histone repressive mark, by the demethylase UTX. Simultaneously, the H3K27me3 demethylase JMJD3/KDM6B was recruited to the transcription start site (TSS), within the gene body and controlled the expression of ENPP2 in a non-enzymatic manner. Mass spectrometry data revealed a novel interaction for JMJD3 with DDX21, a RNA helicase that unwinds R-loops created by nascent transcript and DNA template. Upon LPS treatment, JMJD3 is necessary for DDX21 recruitment at ENPP2 locus allowing the resolution of aberrant R-loops. CRISPR-Cas9-mediated deletion of a distant-acting enhancer decreased the expression of ENPP2 and lowered the recruitment of JMJD3–DDX21 complex at TSS and its progression through the gene body. Taken together, these findings revealed that enhancer-mediated enrichment of novel JMJD3–DDX21 interaction at ENPP2 locus is necessary for nascent transcript synthesis via the resolution of aberrant R-loops formation in response to inflammatory stimulus.

Many Faces of TRIM Proteins on the Road from Pluripotency to Neurogenesis

Tripartite motif (TRIM) proteins participate in numerous biological processes. They are the key players in immune system and are involved in the oncogenesis. Moreover, TRIMs are the highly conserved regulators of developmental pathways in both vertebrates and invertebrates. In particular, numerous data point to the participation of TRIMs in the determination of stem cell fate, as well as in the neurogenesis. TRIMs apply various mechanisms to perform their functions. Their common feature is the ability to ubiquitinate proteins mediated by the Really Interesting New Gene (RING) domain. Different C-terminal domains of TRIMs are involved in DNA and RNA binding, protein/protein interactions, and chromatin-mediated transcriptional regulation. Mutations and alterations of TRIM expression cause significant disturbances in the stem cells' self-renewal and neurogenesis, which result in the various pathologies of the nervous system (neurodegeneration, neuroinflammation, and malignant transformation). This review discusses the diverse molecular mechanisms of participation of TRIMs in stem cell maintenance and self-renewal as well as in neural differentiation processes and neuropathology.

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.

JMJD3 in the regulation of human diseases

In recent years, many studies have shown that histone methylation plays an important role in maintaining the active and silent state of gene expression in human diseases. The Jumonji domain-containing protein D3 (JMJD3), specifically demethylate di- and trimethyl-lysine 27 on histone H3 (H3K27me2/3), has been widely studied in immune diseases, infectious diseases, cancer, developmental diseases, and aging related diseases. We will focus on the recent advances of JMJD3 function in human diseases, and looks ahead to the future of JMJD3 gene research in this review.

JMJD3 promotes the epithelial-mesenchymal transition and migration of glioma cells via the CXCL12/CXCR4 axis

Histone H3K27 demethylase Jumonji domain-containing protein 3 (JMJD3) is involved in somatic cell differentiation and tumor progression; however, the underlying mechanisms of JMJD3 in cancer progression are yet to be fully explored. To improve understanding regarding the function of JMJD3 in brain tumor cells, the present study investigated the effects of JMJD3 on the epithelial-mesenchymal transition (EMT) and migration in glioma cells, and the underlying mechanisms involving the C-X-C motif chemokine ligand 12 (CXCL12)/C-X-C motif chemokine receptor 4 (CXCR4) axis. Immunohistochemical staining of a tissue microarray of glioma samples confirmed that JMJD3 overexpression could stratify highly metastatic glioma. The overexpression of JMJD3 induced a spindle-shaped morphology, promoted N-cadherin expression, inhibited E-cadherin expression and enhanced the migration ability of U-251MG and U-87MG American Type Culture Collection cells. The expression of E-cadherin and N-cadherin were assessed by western blotting and reverse transcription-quantitative polymerase chain reaction, and cell migration was evaluated using a Transwell migration assay and wound-healing. The overexpression of JMJD3 upregulated CXCL12 expression in a demethylase activity-dependent manner as ChIP assays revealed a decrease in H3K27 trimethylation at the CXCL12 promoter following overexpression of JMJD3 in U-87MG ATCC cells. Accordingly, CXCL12 overexpression was sufficient to rescue the suppressive effects of JMJD3 inhibition on the EMT and migration in glioma cells. In addition, CXCR4 expression was not regulated by JMJD3, but the interruption of CXCR4 caused by the CXCR4 inhibitor AMD3100 abolished the promotional effect of JMJD3 on EMT and migration in glioma cells. Collectively, these results suggested that JMJD3 promoted EMT and migration in glioma cells via the CXCL12/CXCR4 axis. The present study described a novel epigenetic mechanism regulating tumor cell EMT and migration, and provided a novel direction for glioma diagnosis and treatment.

The role and prospect of JMJD3 in stem cells and cancer

Currently, stem cells are reported to be involved in tumor formation, drug resistance and recurrence. Inhibiting the proliferation of tumor cells, promoting their senescence and apoptosis has been the most important anti-tumor therapy. Epigenetics is involved in the regulation of gene expression and is closely related to cancer and stem cells. It mainly includes DNA methylation, histone modification, and chromatin remodeling. Histone methylation and demethylation play an important role in histone modification. Histone 3 lysine 27 trimethylation (H3K27me3) induces transcriptional inhibition and plays an important role in gene expression. Jumonji domain-containing protein-3 (JMJD3), one of the demethyases of histone H3K27me3, has been reported to be associated with the prognosis of many cancers and stem cells differentiation. Inhibition of JMJD3 can reduce proliferation and promote apoptosis in tumor cells, as well as suppress differentiation in stem cells. GSK-J4 is an inhibitor of demethylase JMJD3 and UTX, which has been shown to possess anti-cancer and inhibition of embryonic stem cells differentiation effects. In this review, we examine how JMJD3 regulates cellular fates of stem cells and cancer cells and references were identified through searches of PubMed, Medline, Web of Science.

PHF20 collaborates with PARP1 to promote stemness and aggressiveness of neuroblastoma cells through activation of SOX2 and OCT4

The differentiation status of neuroblastoma (NB) strongly correlates with its clinical outcomes; however, the molecular mechanisms driving maintenance of stemness and differentiation remain poorly understood. Here, we show that plant homeodomain finger-containing protein 20 (PHF20) functions as a critical epigenetic regulator in sustaining stem cell-like phenotype of NB by using CRISPR/Cas9-based targeted knockout (KO) for high-throughput screening of gene function in NB cell differentiation. The expression of PHF20 in NB was significantly associated with high aggressiveness of the tumor and poor outcomes for NB patients. Deletion of PHF20 inhibited NB cell proliferation, invasive migration, and stem cell-like traits. Mechanistically, PHF20 interacts with poly(ADP-ribose) polymerase 1 (PARP1) and directly binds to promoter regions of octamer-binding transcription factor 4 (OCT4) and sex determining region Y-box 2 (SOX2) to modulate a histone mark associated with active transcription, trimethylation of lysine 4 on histone H3 protein subunit (H3K4me3). Overexpression of OCT4 and SOX2 restored growth and progression of PHF20 KO tumor cells. Consistently, OCT4 and SOX2 protein levels in clinical NB specimens were positively correlated with PHF20 expression. Our results establish PHF20 as a key driver of NB stem cell-like properties and aggressive behaviors, with implications for prognosis and therapy.

KDM6B overexpression activates innate immune signaling and impairs hematopoiesis in mice

KDM6B is an epigenetic regulator that mediates transcriptional activation during differentiation, including in bone marrow (BM) hematopoietic stem and progenitor cells (HSPCs). Overexpression of KDM6B has been reported in BM HSPCs of patients with myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML). Whether the overexpression of KDM6B contributes to the pathogenesis of these diseases remains to be elucidated. To study this, we generated a Vav-KDM6B mouse model, which overexpresses KDM6B in the hematopoietic compartment. KDM6B overexpression alone led to mild hematopoietic phenotype, and chronic innate immune stimulation of Vav-KDM6B mice with the Toll-like receptor (TLR) ligand lipopolysaccharide (LPS) resulted in significant hematopoietic defects. These defects recapitulated features of MDS and CMML, including leukopenia, dysplasia, and compromised repopulating function of BM HSPCs. Transcriptome studies indicated that KDM6B overexpression alone could lead to activation of disease-relevant genes such as S100a9 in BM HSPCs, and when combined with innate immune stimulation, KDM6B overexpression resulted in more profound overexpression of innate immune and disease-relevant genes, indicating that KDM6B was involved in the activation of innate immune signaling in BM HSPCs. Finally, pharmacologic inhibition of KDM6B with the small molecule inhibitor GSK-J4 ameliorated the ineffective hematopoiesis observed in Vav-KDM6B mice. This effect was also observed when GSK-J4 was applied to the primary BM HSPCs of patients with MDS by improving their repopulating function. These results indicate that overexpression of KDM6B mediates activation of innate immune signals and has a role in MDS and CMML pathogenesis, and that KDM6B targeting has therapeutic potential in these myeloid disorders.

ASXL1 impairs osteoclast formation by epigenetic regulation of NFATc1

Additional sex comb-like 1 (ASXL1) mutations are commonly associated with myeloid malignancies and are markers of aggressive disease. The fact that ASXL1 is necessary for myeloid differentiation raises the possibility it also regulates osteoclasts. We find deletion of ASXL1 in myeloid cells results in bone loss with increased abundance of osteoclasts. Because ASXL1 is an enhancer of trithorax and polycomb (ETP) protein, we asked if it modulates osteoclast differentiation by maintaining balance between positive and negative epigenetic regulators. In fact, loss of ASXL1 induces concordant loss of inhibitory H3K27me3 with gain of H3K4me3 at key osteoclast differentiation genes, including nuclear factor for activated T cells 1 (NFATc1) and itgb3 In the setting of ASXL1 deficiency, increased NFATc1 binds to the Blimp1 (Prdm1) promoter thereby enhancing expression of this pro-osteoclastogenic gene. The global reduction of K27 trimethylation in ASXL1-deficient osteoclasts is also attended by a 40-fold increase in expression of the histone demethylase Jumonji domain-containing 3 (Jmjd3). Jmjd3 knockdown in ASXL1-deficient osteoclast precursors increases H3K27me3 on the NFATc1 promoter and impairs osteoclast formation. Thus, in addition to promoting myeloid malignancies, ASXL1 controls epigenetic reprogramming of osteoclasts to regulate bone resorption and mass.

The Unexpected Noncatalytic Roles of Histone Modifiers in Development and Disease

Epigenetic regulation is critical for the precise control of cellular fate and developmental programs. Disruption of epigenetic information is increasingly appreciated as a potential driving mechanism in both developmental disorders as well as ubiquitous diseases such as cancer. Consistent with this, mutations in histone modifying enzymes are amongst the most frequent events in all of human cancer. While early studies have focused on the canonical enzymatic functions involved in catalyzing modifications to histones, more recent studies have uncovered a new layer of critical nonenzymatic roles in transcriptional regulation for these proteins. Here, we provide an overview of these surprising, yet exciting, noncanonical, noncatalytic roles, and highlight how these revelations may have important implications for understanding disease and the future of epigenome-targeting therapies.

The non-specific lethal (NSL) complex at the crossroads of transcriptional control and cellular homeostasis

The functionality of chromatin is tightly regulated by post-translational modifications that modulate transcriptional output from target loci. Among the post-translational modifications of chromatin, reversible ε-lysine acetylation of histone proteins is prominent at transcriptionally active genes. Lysine acetylation is catalyzed by lysine acetyltransferases (KATs), which utilize the central cellular metabolite acetyl-CoA as their substrate. Among the KATs that mediate lysine acetylation, males absent on the first (MOF/KAT8) is particularly notable for its ability to acetylate histone 4 lysine 16 (H4K16ac), a modification that decompacts chromatin structure. MOF and its non-specific lethal (NSL) complex members have been shown to localize to gene promoters and enhancers in the nucleus, as well as to microtubules and mitochondria to regulate key cellular processes. Highlighting their importance, mutations or deregulation of NSL complex members has been reported in both human neurodevelopmental disorders and cancer. Based on insight gained from studies in human, mouse, and Drosophila model systems, this review discusses the role of NSL-mediated lysine acetylation in a myriad of cellular functions in both health and disease. Through these studies, the importance of the NSL complex in regulating core transcriptional and signaling networks required for normal development and cellular homeostasis is beginning to emerge.

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.

Identification of the 2-Benzoxazol-2-yl-phenol Scaffold as New Hit for JMJD3 Inhibition

JMJD3 is a member of the KDM6 subfamily and catalyzes the demethylation of lysine 27 on histone H3 (H3K27). This protein was identified as a useful tool in understanding the role of epigenetics in inflammatory conditions and in cancer as well. Guided by a virtual fragment screening approach, we identified the benzoxazole scaffold as a new hit suitable for the development of tighter JMJD3 inhibitors. Compounds were synthesized by a microwave-assisted one-pot reaction under catalyst and solvent-free conditions. Among these, compound 8 presented the highest inhibitory activity (IC₅₀ = 1.22 ± 0.22 μM) in accordance with molecular modeling calculations. Moreover, 8 induced the cycle arrest in S-phase on A375 melanoma cells.

Comprehensive profiling of JMJD3 in gastric cancer and its influence on patient survival

Histone methylation is thought to control the regulation of genetic program and the dysregulation of it has been found to be closely associated with cancer. JMJD3 has been identified as an H3K27 demethylase and its role in cancer development is context specific. The role of JMJD3 in gastric cancer (GC) has not been examined. In this study, JMJD3 expression was determined. The prognostic significance of JMJD3 and its association with clinical parameters were evaluated. JMJD3 dysregulation mechanism and targets were analyzed. The effect of JMJD3 mutation was determined by functional study. Results showed that JMJD3 was overexpressed in different patient cohorts and also by bioinformatics analysis. High JMJD3 expression was correlated with shortened overall survival in patients with GC and was an independent prognosis predictor. Genetic aberration and DNA methylation might be involved in the deregulation of JMJD3 in GC. Downstream network of JMJD3 was analyzed and several novel potential targets were identified. Furthermore, functional study discovered that both demethylase-dependent and demethylase-independent mechanisms were involved in the oncogenic role of JMJD3 in GC. Importantly, histone demethylase inhibitor GSK-J4 could reverse the oncogenic effect of JMJD3 overexpression. In conclusion, our study report the oncogenic role of JMJD3 in GC for the first time. JMJD3 might serve as an important epigenetic therapeutic target and/or prognostic predictor in GC.