Exploring host epigenetic enzymes as targeted therapies for visceral leishmaniasis: in silico design and in vitro efficacy of KDM6B and ASH1L inhibitors

In order to combat various infectious diseases, the utilization of host-directed therapies as an alternative to chemotherapy has gained a lot of attention in the recent past, since it bypasses the existing limitations of conventional therapies. The use of host epigenetic enzymes like histone lysine methyltransferases and lysine demethylases as potential drug targets has successfully been employed for controlling various inflammatory diseases like rheumatoid arthritis and acute leukemia. In our earlier study, we have already shown that the functional knockdown of KDM6B and ASH1L in the experimental model of visceral leishmaniasis has resulted in a significant reduction of organ parasite burden. Herein, we performed a high throughput virtual screening against KDM6B and ASH1L using > 53,000 compounds that were obtained from the Maybridge library and PubChem Database, followed by molecular docking to evaluate their docking score/Glide Gscore. Based on their docking scores, the selected inhibitors were later assessed for their in vitro anti-leishmanial efficacy. Out of all inhibitors designed against KDM6B and ASH1L, HTS09796, GSK-J4 and AS-99 particularly showed promising in vitro activity with IC50 < 5 µM against both extracellular promastigote and intracellular amastigote forms of L. donovani. In vitro drug interaction studies of these inhibitors further demonstrated their synergistic interaction with amphotericin-B and miltefosine. However, GSK-J4 makes an exception by displaying an in different mode of interaction with miltefosine. Collectively, our in silico and in vitro studies acted as a platform to identify the applicability of these inhibitors targeted against KDM6B and ASH1L for anti-leishmanial therapy.

Cerebellar heterotopia in an 11-year-old child with KDM6B-related neurodevelopmental disorder: A case report and review of the literature

Heterozygous pathogenic variants in KDM6B have recently been associated to a rare neurodevelopmental disorder referred to as "Neurodevelopmental disorder with coarse facies and mild distal skeletal abnormalities" and characterized by non-pathognomonic facial and body dysmorphisms, a wide range of neurodevelopmental and behavioral disorders and nonspecific neuroradiological findings. KDM6B encodes a histone demethylase, expressed in different tissues during development, which regulates gene expression through the modulation of chromatin accessibility by RNA polymerase. We herein describe a 11-year-old male patient carrying a novel de novo pathogenic variant in KDM6B exhibiting facial dysmorphisms, dysgraphia, behavioral traits relatable to oppositional defiant, autism spectrum, and attention deficit hyperactivity disorders, a single seizure episode, and a neuroimaging finding of a single cerebellar heterotopic nodule, never described to date in this genetic condition. These findings expand the phenotypic spectrum of this syndrome, highlighting the potential role for KDM6B in cerebellar development and providing valuable insights for genetic counseling.

MicroRNA-93-5p regulates odontogenic differentiation and dentin formation via KDM6B

BACKGROUND

Epigenetic factors influence the odontogenic differentiation of dental pulp stem cells and play indispensable roles during tooth development. Some microRNAs can epigenetically regulate other epigenetic factors like DNA methyltransferases and histone modification enzymes, functioning as epigenetic-microRNAs. In our previous study, microarray analysis suggested microRNA-93-5p (miR-93-5p) was differentially expressed during the bell stage in human tooth germ. Prediction tools indicated that miR-93-5p may target lysine-specific demethylase 6B (KDM6B). Therefore, we explored the role of miR-93-5p as an epi-miRNA in tooth development and further investigated the underlying mechanisms of miR-93-5p in regulating odontogenic differentiation and dentin formation.

METHODS

The expression pattern of miR-93-5p and KDM6B of dental pulp stem cells (DPSCs) was examined during tooth development and odontogenic differentiation. Dual luciferase reporter and ChIP-qPCR assay were used to validate the target and downstream regulatory genes of miR-93-5p in human DPSCs (hDPSCs). Histological analyses and qPCR assays were conducted for investigating the effects of miR-93-5p mimic and inhibitor on odontogenic differentiation of hDPSCs. A pulpotomy rat model was further established, microCT and histological analyses were performed to explore the effects of KDM6B-overexpression and miR-93-5p inhibition on the formation of tertiary dentin.

RESULTS

The expression level of miR-93-5p decreased as odontoblast differentiated, in parallel with elevated expression of histone demethylase KDM6B. In hDPSCs, miR-93-5p overexpression inhibited the odontogenic differentiation and vice versa. MiR-93-5p targeted 3' untranslated region (UTR) of KDM6B, thereby inhibiting its protein translation. Furthermore, KDM6B bound the promoter region of BMP2 to demethylate H3K27me3 marks and thus upregulated BMP2 transcription. In the rat pulpotomy model, KDM6B-overexpression or miR-93-5p inhibition suppressed H3K27me3 level in DPSCs and consequently promoted the formation of tertiary dentin.

CONCLUSIONS

MiR-93-5p targets epigenetic regulator KDM6B and regulates H3K27me3 marks on BMP2 promoters, thus modulating the odontogenic differentiation of DPSCs and dentin formation.

Echinococcus granulosus cyst fluid inhibits KDM6B-mediated demethylation of trimethylated histone H3 lysine 27 and interleukin-1β production in macrophages

BACKGROUND

Echinococcus granulosus can manipulate its host's immune response to ensure its own survival. However, the effect of histone modifications on the regulation of the NOD-like receptor protein 3 (NLRP3) inflammasome and downstream interleukin-1β (IL-1β) production in response to the parasite is not fully understood.

METHODS

We evaluated IL-1β secretion through enzyme-linked immunosorbent assay and assessed reactive oxygen species levels using the dichlorodihydrofluorescein diacetate probe. Western blotting and quantitative real-time polymerase chain reaction were performed to examine the expression of NLRP3 and IL-1β in mouse peritoneal macrophages and Tohoku Hospital Pediatrics-1 cells, a human macrophage cell line. The presence of trimethylated histone H3 lysine 27 (H3K27me3) modification on NLRP3 and IL-1β promoters was studied by chromatin immunoprecipitation.

RESULTS

Treatment with E. granulosus cyst fluid (EgCF) considerably reduced IL-1β secretion in mouse and human macrophages, although reactive oxygen species production increased. EgCF also suppressed the expression of NLRP3 and IL-1β. Mechanistically, EgCF prompted the enrichment of repressive H3K27me3 modification on the promoters of both NLRP3 and IL-1β in macrophages. Notably, the presence of EgCF led to a significant reduction in the expression of the H3K27me3 demethylase KDM6B.

CONCLUSIONS

Our study revealed that EgCF inhibits KDM6B expression and H3K27me3 demethylation, resulting in the transcriptional inhibition of NLRP3 and IL-1β. These results provide new insights into the immune evasion mechanisms of E. granulosus.

Sensory neuron-specific long noncoding RNA in small non-peptidergic dorsal root ganglion neurons selectively impairs nerve injury-induced mechanical hypersensitivity

AIMS

Nerve injury-induced mechanical hypersensitivity is one of major clinical symptoms in neuropathic pain patients. Understanding molecular mechanisms underlying this symptom is crucial for developing effective therapies. The present study was to investigate whether sensory neuron-specific long noncoding RNA (SS-lncRNA) predominantly expressed in small non-peptidergic dorsal root ganglion (DRG) neurons repaired nerve injury-induced mechanical hypersensitivity.

MATERIALS AND METHODS

SS-lncRNA downregulation in the mas-related G protein-coupled receptor member D (Mrgprd)-expressed DRG neurons was rescued and mimicked by crossbreeding MrgprdCreERT2/+ lines with Rosa26SS-lncRNA knock-in mice and SS-lncRNAfl/fl mice, respectively, followed by tamoxifen injection.

KEY FINDINGS

Rescuing SS-lncRNA downregulation in the Mrgprd-expressed DRG neurons significantly reversed the spinal nerve ligation (SNL)-induced reduction of the calcium-activated potassium channel subfamily N member 1 (KCNN1) in these DRG neurons and alleviated the SNL-induced mechanical hypersensitivity, without affecting the SNL-induced heat and cold nociceptive hypersensitivities, on the ipsilateral side. Conversely, mimicking SS-lncRNA downregulation in the Mrgprd-expressed DRG neurons reduced basal KCNN1 expression in these DRG neurons and produced the enhanced response to mechanical stimulation, but not thermal and cold stimuli, on bilateral sides. Mechanistically, SS-lncRNA downregulation caused a reduction in its binding to lysine-specific demethylase 6B (KDM6B) and consequent recruitment of less KDM6B to Kcnn1 promoter and an increase of H3K27me3 enrichment in this promoter in injured DRG.

SIGNIFICANCE

Our findings suggest that SS-lncRNA downregulation in small non-peptidergic sensory neurons is required specifically for nerve injury-induced mechanical hypersensitivity likely through silencing KCNN1 expression caused by KDM6B-gated increase of H3K27me3 enrichment in Kcnn1 promoter in these neurons.

E2F1-driven histone demethylase KDM6B enhances thyroid malignancy via manipulating TFEB-dependent autophagy axis

Aberrant epigenetic modifications or events regulate autophagy to influence tumor progression, which has gained increasing attention. KDM6B is an essential histone demethylase that participates in multiple processes of tumors, but its role in thyroid carcinoma (THCA) remains to be unknown. Here, in this study, we used the MTT assay to screen and validate that KDM6B is an essential demethylase for THCA. KDM6B promotes THCA proliferation, migration, invasion in vitro and in vivo. Transcriptional factor E2F1 directly binds to the promoter region of KDM6B and regulates its mRNA levels in THCA. E2F1 partially depended on KDM6B to exert its oncogenic functions. Mechanistically, KDM6B binds to TFEB promoter region and mediates the demethylation of H3K27me3. KDM6B depended on TFEB to activate a series of lysosomal-related genes. KDM6B enhances autophagy process, as evidenced by elevated p62 and Beclin-1 proteins. KDM6B depended on TFEB-driven autophagy activity to accelerate THCA progression. Lastly, targeting autophagy with 3-MA could notably abrogate growth of KDM6Bhigh THCA, but has mild influence on KDM6Blow THCA. Together, this study identified KDM6B as an essential epigenetic regulator for THCA, functioning as an autophagy regulator. The fundamental mechanisms underlying E2F1/KDM6B/TFEB axis provided novel vulnerabilities for THCA treatment.

Dopamine Transporter Knockout Rats Display Epigenetic Alterations in Response to Cocaine Exposure

(1) Background: There is an urgent need for effective treatments for cocaine use disorder (CUD), and new pharmacological approaches targeting epigenetic mechanisms appear to be promising options for the treatment of this disease. Dopamine Transporter (DAT) transgenic rats recently have been proposed as a new animal model for studying susceptibility to CUD. (2) Methods: DAT transgenic rats were treated chronically with cocaine (10 mg/kg) for 8 days, and the expression of epigenetic modulators, Lysine Demethylase 6B (KDM6B) and Bromodomain-containing protein 4 (BRD4), was examined in the prefrontal cortex (PFC). (3) Results: We show that only full knockout (KO) of DAT impacts basal levels of KDM6B in females. Additionally, cocaine altered the expression of both epigenetic markers in a sex- and genotype-dependent manner. In response to chronic cocaine, KDM6B expression was decreased in male rats with partial DAT mutation (HET), while no changes were observed in wild-type (WT) or KO rats. Indeed, while HET male rats have reduced KDM6B and BRD4 expression, HET female rats showed increased KDM6B and BRD4 expression levels, highlighting the impact of sex on epigenetic mechanisms in response to cocaine. Finally, both male and female KO rats showed increased expression of BRD4, but only KO females exhibited significantly increased KDM6B expression in response to cocaine. Additionally, the magnitude of these effects was bigger in females when compared to males for both epigenetic enzymes. (4) Conclusions: This preliminary study provides additional support that targeting KDM6B and/or BRD4 may potentially be therapeutic in treating addiction-related behaviors in a sex-dependent manner.

The clinical and molecular spectrum of the KDM6B-related neurodevelopmental disorder

De novo variants are a leading cause of neurodevelopmental disorders (NDDs), but because every monogenic NDD is different and usually extremely rare, it remains a major challenge to understand the complete phenotype and genotype spectrum of any morbid gene. According to OMIM, heterozygous variants in KDM6B cause "neurodevelopmental disorder with coarse facies and mild distal skeletal abnormalities." Here, by examining the molecular and clinical spectrum of 85 reported individuals with mostly de novo (likely) pathogenic KDM6B variants, we demonstrate that this description is inaccurate and potentially misleading. Cognitive deficits are seen consistently in all individuals, but the overall phenotype is highly variable. Notably, coarse facies and distal skeletal anomalies, as defined by OMIM, are rare in this expanded cohort while other features are unexpectedly common (e.g., hypotonia, psychosis, etc.). Using 3D protein structure analysis and an innovative dual Drosophila gain-of-function assay, we demonstrated a disruptive effect of 11 missense/in-frame indels located in or near the enzymatic JmJC or Zn-containing domain of KDM6B. Consistent with the role of KDM6B in human cognition, we demonstrated a role for the Drosophila KDM6B ortholog in memory and behavior. Taken together, we accurately define the broad clinical spectrum of the KDM6B-related NDD, introduce an innovative functional testing paradigm for the assessment of KDM6B variants, and demonstrate a conserved role for KDM6B in cognition and behavior. Our study demonstrates the critical importance of international collaboration, sharing of clinical data, and rigorous functional analysis of genetic variants to ensure correct disease diagnosis for rare disorders.

miR-29c-3p Accelerates Mucosal Injury in Dextran Sodium Sulfate-induced Ulcerative Colitis Mice through the KDM6B/ H3K27me3/LDHA axis

BACKGROUND

Ulcerative colitis (UC) is an inflammatory intestinal disorder featured by mucosal injury. MicroRNAs (miRNAs) play a role in the pathogenesis underlying UC.

OBJECTIVES

This study was conducted to investigate the role of miR-29c-3p in a dextran sodium sulfate (DSS)-induced UC mouse model and provide targets for UC treatment.

METHODS

The UC mouse model was established by DSS induction. The expression levels of miR-29c-3p, lysine-specific demethylase 6B (KDM6B), zonula occludens-1 (ZO-1), Occludin, and lactate dehydrogenase A (LDHA) were detected by real-time quantitative polymerase chain reaction or Western blot assays. The mucosal injury was evaluated by disease activity index (DAI), colon length, Hematoxylin-Eosin staining, and fluorescein isothiocyanate-glucan permeability test. The binding between miR-29c-3p and KDM6B and the occupation of KDM6B or trimethylated H3 lysine 27 (H3K27me3) on the LDHA promoter were analyzed by the dual-luciferase and chromatin-immunoprecipitation assays.

RESULTS

miR-29c-3p was downregulated while KDM6B and LDHA were upregulated in DSS mice. miR-29c-3p overexpression reduced DAI and inflammatory cell infiltration while increasing colon length, intestinal permeability, and levels of ZO-1 and Occludin. miR-29c-3p inhibited KDM6B expression and increased H3K27me3 occupation on the LDHA promoter, thus inhibiting LDHA transcription. Overexpression of KDM6B or LDHA averted the protective role of miR-29c-3p upregulation in mucosal injury.

CONCLUSION

miR-29c-3p limited KDM6B expression and increased the H3K27me3 occupation on the LDHA promoter to enhance LDHA transcription, moderating mucosal injury and delaying UC progression.

Transcriptome characterization of human gingival mesenchymal and periodontal ligament stem cells in response to electronic-cigarettes

The potential toxicities and threats of electronic cigarettes (E-cigs) on periodontal health remain elusive. Gingival mesenchymal stem cells (GMSCs) and periodontal ligament stem cells (PDLSCs) contribute to cell differentiation and regeneration for periodontium as well as inflammatory modulation. However, the effects of E-cig exposure on periodontal tissues, particularly GMSCs and PDLSCs, and the underlying epigenetic mechanisms remain largely unknown. In this study, we conducted RNA-seq analysis to examine the transcriptome of human GMSCs and PDLSCs exposed to four types of E-cigs (aerosol and liquid with tobacco and menthol flavor) and conventional tobacco smoke in vitro. Our results showed that E-cig exposure primarily impacted the immunoregulation and inflammatory responses to pathogenic microorganisms in GMSCs, and the microenvironment, differentiation and response to corticosteroid in PDLSCs, which were significantly different from the damage effects caused by tobacco smoke. Additionally, we discovered a large number of differentially expressed non-coding RNAs among the different E-cig exposure methods and flavors. We also noticed that in GMSCs, CXCL2 was especially down-regulated by E-cig aerosol exposure whereas up-regulated by E-liquid exposure compared to control. Of note, the enhancer elements near CXCL2 and other genes located at Chromosome 4 contributed to the transcription activity of these genes, and KDM6B was remarkably elevated in response to E-liquid exposure. Lastly, we conducted ChIP-seq analysis to confirm that the elevated gene transcription by E-liquids was due to the weakened H3K27me3 at genome-wide enhancer elements in GMSCs, but not at promoter regions. Taken together, our results characterized the diverse gene expression profiles of GMSCs and PDLSCs in response to E-cigs with different exposure methods and flavors in vitro, and indicated a novel mechanism of KDM6B-mediated H3K27me3 on enhancers for gene transcription regulation. Our data could be served as a resource for emphasizing the understanding of E-cigs in periodontal health.

Dual-Targeted Nanodiscs Revealing the Cross-Talk between Osteogenic Differentiation of Mesenchymal Stem Cells and Macrophages

Ongoing research has highlighted the significance of the cross-play of macrophages and mesenchymal stem cells (MSCs). Lysine-specific demethylase 6B (KDM6B) has been shown to control osteogenic differentiation of MSCs by depleting trimethylated histone 3 lysine 27 (H3K27me3). However, to date, the role of KDM6B in bone marrow-derived macrophages (BMDMs) remains controversial. Here, a chromatin immunoprecipitation assay (ChIP) proved that KDM6B derived from osteogenic-induced BMSCs could bind to the promoter region of BMDMs' brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein-1 (BMAL1) gene in a coculture system and activate BMAL1. Transcriptome sequencing and experiments in vitro showed that the overexpression of BMAL1 in BMDM could inhibit the TLR2/NF-κB signaling pathway, reduce pyroptosis, and decrease the M1/M2 ratio, thereby promoting osteogenic differentiation of BMSCs. Furthermore, bone and macrophage dual-targeted GSK-J4 (KDM6B inhibitor)-loaded nanodiscs were synthesized via binding SDSSD-apoA-1 peptide analogs (APA) peptide, which indirectly proved the critical role of KDM6B in osteogenesis in vivo. Overall, we demonstrated that KDM6B serves as a positive circulation trigger during osteogenic differentiation by decreasing the ratio of M1/M2 both in vitro and in vivo. Collectively, these results provide insight into basic research in the field of osteoporosis and bone repair.

KDM6B regulates M2 polarization of macrophages by modulating the stability of nuclear β-catenin

Accumulating evidences suggest that the epigenetic regulation plays a pivotal role in establishing phenotype and function of tumor associated macrophages (TAMs). KDM6B is an epigenetic enzyme responsible for the H3K27me3 and reported to influence macrophage polarization. However, the underlying mechanism remains to be determined. Here, we demonstrated that inhibition of KDM6B in TAMs increased M2 polarization induced by coculture of breast cancer cells. Furthermore, we identified that KDM6B downregulation activated β-catenin/c-Myc signaling, and thus promoted the M2-like phenotype. KDM6B accelerated the intranuclear ubiquitination degradation of β-catenin, which depended on its demethylase activity. Therapeutically, our data showed that activated vitamin D analog paricalcitol upregulated the expression of KDM6B and decreased the M2 polarization, consequently protected against tumor progress in the xenograft mouse model of breast cancer. Taken together, our data reveal that epigenetic regulator KDM6B prevents M2 polarization via promoting the intranuclear degradation of β-catenin. Active vitamin D analog induces KDM6B and suppresses tumor progress, suggesting a novel therapeutic potential of epigenetic modulation for the tumor treatment.

KDM6B Variants May Contribute to the Pathophysiology of Human Cerebral Folate Deficiency

(1) Background: The genetic etiology of most patients with cerebral folate deficiency (CFD) remains poorly understood. KDM6B variants were reported to cause neurodevelopmental diseases; however, the association between KDM6B and CFD is unknown; (2) Methods: Exome sequencing (ES) was performed on 48 isolated CFD cases. The effect of KDM6B variants on KDM6B protein expression, Histone H3 lysine 27 epigenetic modification and FOLR1 expression were examined in vitro. For each patient, serum FOLR1 autoantibodies were measured; (3) Results: Six KDM6B variants were identified in five CFD patients, which accounts for 10% of our CFD cohort cases. Functional experiments indicated that these KDM6B variants decreased the amount of KDM6B protein, which resulted in elevated H3K27me2, lower H3K27Ac and decreased FOLR1 protein concentrations. In addition, FOLR1 autoantibodies have been identified in serum; (4) Conclusion: Our study raises the possibility that KDM6B may be a novel CFD candidate gene in humans. Variants in KDM6B could downregulate FOLR1 gene expression, and might also predispose carriers to the development of FOLR1 autoantibodies.

H3K27me3 Demethylases Maintain the Transcriptional and Epigenomic Landscape of the Intestinal Epithelium

BACKGROUND & AIMS

Although trimethylation of histone H3 lysine 27 (H3K27me3) by polycomb repressive complex 2 is required for intestinal function, the role of the antagonistic process-H3K27me3 demethylation-in the intestine remains unknown. The aim of this study was to determine the contribution of H3K27me3 demethylases to intestinal homeostasis.

METHODS

An inducible mouse model was used to simultaneously ablate the 2 known H3K27me3 demethylases, lysine (K)-specific demethylase 6A (Kdm6a) and lysine (K)-specific demethylase 6B (Kdm6b), from the intestinal epithelium. Mice were analyzed at acute and prolonged time points after Kdm6a/b ablation. Cellular proliferation and differentiation were measured using immunohistochemistry, while RNA sequencing and chromatin immunoprecipitation followed by sequencing for H3K27me3 were used to identify gene expression and chromatin changes after Kdm6a/b loss. Intestinal epithelial renewal was evaluated using a radiation-induced injury model, while Paneth cell homeostasis was measured via immunohistochemistry, immunoblot, and transmission electron microscopy.

RESULTS

We did not detect any effect of Kdm6a/b ablation on intestinal cell proliferation or differentiation toward the secretory cell lineages. Acute and prolonged Kdm6a/b loss perturbed expression of gene signatures belonging to multiple cell lineages (adjusted P value < .05), and a set of 72 genes was identified as being down-regulated with an associated increase in H3K27me3 levels after Kdm6a/b ablation (false discovery rate, <0.05). After prolonged Kdm6a/b loss, dysregulation of the Paneth cell gene signature was associated with perturbed matrix metallopeptidase 7 localization (P < .0001) and expression.

CONCLUSIONS

Although KDM6A/B does not regulate intestinal cell differentiation, both enzymes are required to support the full transcriptomic and epigenomic landscape of the intestinal epithelium and the expression of key Paneth cell genes.

Therapeutic potential of inhibiting histone 3 lysine 27 demethylases: a review of the literature

Histone 3 lysine 27 (H3K27) demethylation constitutes an important epigenetic mechanism of gene activation. It is mediated by the Jumonji C domain-containing lysine demethylases KDM6A and KDM6B, both of which have been implicated in a wide myriad of diseases, including blood and solid tumours, autoimmune and inflammatory disorders, and infectious diseases. Here, we review and summarise the pre-clinical evidence, both in vitro and in vivo, in support of the therapeutic potential of inhibiting H3K27-targeting demethylases, with a focus on the small-molecule inhibitor GSK-J4. In malignancies, KDM6A/B inhibition possesses the ability to inhibit proliferation, induce apoptosis, promote differentiation, and heighten sensitivity to currently employed chemotherapeutics. KDM6A/B inhibition also comprises a potent anti-inflammatory approach in inflammatory and autoimmune disorders associated with inappropriately exuberant inflammatory and autoimmune responses, restoring immunological homeostasis to inflamed tissues. With respect to infectious diseases, KDM6A/B inhibition can suppress the growth of infectious pathogens and attenuate the immunopathology precipitated by these pathogens. The pre-clinical in vitro and in vivo data, summarised in this review, suggest that inhibiting H3K27 demethylases holds immense therapeutic potential in many diseases.

Synergistic effects of ISL1 and KDM6B on non-alcoholic fatty liver disease through the regulation of SNAI1

Background

The increasing incidence of non-alcoholic fatty liver disease (NAFLD) has been reported worldwide, which urges understanding of its pathogenesis and development of more effective therapeutical methods for this chronic disease. In this study, we aimed to investigate the effects of a LIM homeodomain transcription factor, islet1 (ISL1) on NAFLD.

Methods

Male C57BL/6J mice were fed with a diet high in fat content to produce NAFLD models. These models were then treated with overexpressed ISL1 (oe-ISL1), oe-Lysine-specific demethylase 6B (KDM6B), oe-SNAI1, or short hairpin RNA against SNAI1. We assessed triglyceride and cholesterol contents in the plasma and liver tissues and determined the expressions of ISL1, KDM6B and SNAI1 in liver tissues. Moreover, the in vitro model of lipid accumulation was constructed using fatty acids to explore the in vitro effect of ISL1/KDM6B/SNAI1 in NAFLD.

Results

The results showed that the expressions of ISL1, KDM6B, and SNAI1 where decreased, but contents of triglyceride and cholesterol increased in mice exposed to high-fat diet. ISL1 inhibited lipogenesis and promoted lipolysis and exhibited a synergizing effect with KDM6B to upregulate the expression of SNAI1. Moreover, both KDM6B and SNAI1 could inhibit lipogenesis and induce lipolysis. Importantly, the therapeutic effects of ISL1 on in vitro model of lipid accumulations was also confirmed through the modulation of KDM6B and SNAI1.

Conclusions

Taken together, these findings highlighted that ISL1 effectively ameliorated NAFLD by inducing the expressions of KDM6B and SNAI1, which might be a promising drug for the treatment of NAFLD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00428-7.

Activation of epigenetic regulator KDM6B by Salmonella Typhimurium enables chronic infections

Non-typhoidal Salmonella (NTS) infections result in self limiting gastroenteritis except in rare cases wherein manifestations of chronic infections can occur. Strategies employed by Salmonella to thrive in hostile environments of host during chronic infections are complex and multifaceted. In chronic state, a coordinated action of bacterial effectors allows reprogramming of macrophages to M2 subtype and thereby creating a permissible replicative niche. The mechanistic details of these processes are not fully known. In the current study we identified, histone H3-lysine 27 trimethylation (H3K27me3)-specific demethylase, KDM6B to be upregulated in both cell culture and in murine model of Salmonella infection. KDM6B recruitment upon infection exhibited an associated loss of overall H3K27me3 in host cells and was Salmonella SPI1 effectors coordinated. ChIP-qRT-PCR array analysis revealed several new gene promoter targets of KDM6B demethylase activity including PPARδ, a crucial regulator of fatty acid oxidation pathway and Salmonella-persistent infections. Furthermore, pharmacological inhibition of KDM6B demethylase activity with GSKJ4 in chronic Salmonella infection mice model led to a significant reduction in pathogen load and M2 macrophage polarization in peripheral lymphoid organs. The following work thus reveals Salmonella effector-mediated epigenetic reprogramming of macrophages responsible for its long-term survival and chronic carriage.

KDM6B epigenetically regulated-interleukin-6 expression in the dorsal root ganglia and spinal dorsal horn contributes to the development and maintenance of neuropathic pain following peripheral nerve injury in male rats

The lysine specific demethylase 6B (KDM6B) has been implicated as a coregulator in the expression of proinflammatory mediators, and in the pathogenesis of inflammatory and arthritic pain. However, the role of KDM6B in neuropathic pain has yet to be studied. In the current study, the neuropathic pain was determined by assessing the paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) following lumbar 5 spinal nerve ligation (SNL) in male rats. Immunohistochemistry, Western blotting, qRT-PCR, and chromatin immunoprecipitation (ChIP)-PCR assays were performed to investigate the underlying mechanisms. Our results showed that SNL led to a significant increase in KDM6B mRNA and protein in the ipsilateral L4/5 dorsal root ganglia (DRG) and spinal dorsal horn; and this increase correlated a markedly reduction in the level of H3K27me3 methylation in the same tissue. Double immunofluorescence staining revealed that the KDM6B expressed in myelinated A- and unmyelinated C-fibers in the DRG; and located in neuronal cells, astrocytes, and microglia in the dorsal horn. Behavioral data showed that SNL-induced mechanical allodynia and thermal hyperalgesia were impaired by the treatment of prior to i.t. injection of GSK-J4, a specific inhibitor of KDM6B, or KDM6B siRNA. Both microinjection of AAV2-EGFP-KDM6B shRNA in the lumbar 5 dorsal horn and sciatic nerve, separately, alleviated the neuropathic pain following SNL. The established neuropathic pain was also partially attenuated by repeat i.t. injections of GSK-J4 or KDM6B siRNA, started on day 7 after SNL. SNL also resulted in a remarkable increased expression of interleukin-6 (IL-6) in the DRG and dorsal horn. But this increase was dramatically inhibited by i.t. injection of GSK-J4 and KDM6B siRNA; and suppressed by prior to microinjection of AAV2-EGFP-KDM6B shRNA in the dorsal horn and sciatic nerve. Results of ChIP-PCR assay showed that SNL-induced enhanced binding of STAT3 with IL-6 promoter was inhibited by prior to i.t. injection of GSK-J4. Meanwhile, the level of H3K27me3 methylation was also decreased by the treatment. Together, our results indicate that SNL-induced upregulation of KDM6B via demethylating H3K27me3 facilitates the binding of STAT3 with IL-6 promoter, and subsequently mediated-increase in the expression of IL-6 in the DRG and dorsal horn contributes to the development and maintenance of neuropathic pain. Targeting KDM6B might a promising therapeutic strategy to treatment of chronic pain.

Depletion of Demethylase KDM6 Enhances Early Neuroectoderm Commitment of Human PSCs

Epigenetic modifications play a crucial role in neurogenesis, learning, and memory, but the study of their role in early neuroectoderm commitment from pluripotent inner cell mass is relatively lacking. Here we utilized the system of directed neuroectoderm differentiation from human embryonic stem cells and identified that KDM6B, an enzyme responsible to erase H3K27me3, was the most upregulated enzyme of histone methylation during neuroectoderm differentiation by transcriptome analysis. We then constructed KDM6B-null embryonic stem cells and found strikingly that the pluripotent stem cells with KDM6B knockout exhibited much higher neuroectoderm induction efficiency. Furthermore, we constructed a series of embryonic stem cell lines knocking out the other H3K27 demethylase KDM6A, and depleting both KDM6A and KDM6B, respectively. These cell lines together confirmed that KDM6 impeded early neuroectoderm commitment. By RNA-seq, we found that the expression levels of a panel of WNT genes were significantly affected upon depletion of KDM6. Importantly, the result that WNT agonist and antagonist could abolish the differential neuroectoderm induction due to manipulating KDM6 further demonstrated that WNT was the major downstream of KDM6 during early neural induction. Moreover, we found that the chemical GSK-J1, an inhibitor of KDM6, could enhance neuroectoderm induction from both embryonic stem cells and induced pluripotent stem cells. Taken together, our findings not only illustrated the important role of the histone methylation modifier KDM6 in early neurogenesis, providing insights into the precise epigenetic regulation in cell fate determination, but also showed that the inhibitor of KDM6 could facilitate neuroectoderm differentiation from human pluripotent stem cells.

Characterizing DNA methylation signatures and their potential functional roles in Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is a rare but aggressive skin cancer with limited treatment possibilities. Merkel cell tumors display with neuroendocrine features and Merkel cell polyomavirus (MCPyV) infection in the majority (80%) of patients. Although loss of histone H3 lysine 27 trimethylation (H3K27me3) has been shown during MCC tumorigenesis, epigenetic dysregulation has largely been overlooked.

METHODS

We conducted global DNA methylation profiling of clinically annotated MCC primary tumors, metastatic skin tumors, metastatic lymph node tumors, paired normal tissues, and two human MCC cell lines using the Illumina Infinium EPIC DNA methylation BeadArray platform.

RESULTS

Significant differential DNA methylation patterns across the genome are revealed between the four tissue types, as well as based on MCPyV status. Furthermore, 964 genes directly regulated by promoter or gene body DNA methylation were identified with high enrichment in neuro-related pathways. Finally, our findings suggest that loss of H3K27me3 occupancy in MCC is attributed to KDM6B and EZHIP overexpression as a consequence of promoter DNA hypomethylation.

CONCLUSIONS

We have demonstrated specific DNA methylation patterns for primary MCC tumors, metastatic MCCs, and adjacent-normal tissues. We have also identified DNA methylation markers that not only show potential diagnostic or prognostic utility in MCC management, but also correlate with MCC tumorigenesis, MCPyV expression, neuroendocrine features, and H3K27me3 status. The identification of DNA methylation alterations in MCC supports the need for further studies to understand the clinical implications of epigenetic dysregulation and potential therapeutic targets in MCC.

Histone demethylase KDM6B inhibits breast cancer metastasis by regulating Wnt/β-catenin signaling

Tumor metastasis remains a major challenge for patients with breast cancer. Aberrant epigenetic factor lysine‐specific demethylase 6B (KDM6B) has been associated with tumor progression. Here, we show that KDM6B is significantly down‐regulated in human breast cancer tissues, and its low expression is associated with poor prognosis of patients with breast cancer. Furthermore, overexpression of KDM6B remarkably inhibited cell proliferation, invasion, migration and epithelial–mesenchymal transition markers of breast cancer cells in vitro and tumor growth and lung metastasis in vivo. Notably, the expression of KDM6B in breast cancer tissues was negatively correlated with that of β‐catenin, and overexpression of KDM6B decreased the expression of β‐catenin and its accumulation in the nucleus of breast cancer cells. Overall, our findings provide novel insights into suppression of metastasis of breast cancer cells by KDM6B via β‐catenin and suggest involvement of the KDM6B‐Wnt/β‐catenin axis in breast cancer progression.

KDM6B promotes ESCC cell proliferation and metastasis by facilitating C/EBPβ transcription

Background

As an H3K27me3 demethylase and counteracts polycomb-mediated transcription repression, KDM6B has been implicated in the development and malignant progression in various types of cancers. However, its potential roles in esophageal squamous cell carcinoma (ESCC) have not been explored.

Methods

The expression of KDM6B in human ESCC tissues and cell lines was examined using RT-qPCR, immunohistochemical staining and immunoblotting. The effects of KDM6B on the proliferation and metastasis of ESCC were examined using in vitro and in vivo functional tests. RNA-seq and ChIP-seq assay were used to demonstrate the molecular biological mechanism of KDM6B in ESCC.

Results

We show that the expression level of KDM6B increased significantly in patients with lymph node metastasis. Furthermore, we confirmed that KDM6B knockdown reduces proliferation and metastasis of ESCC cells, while KDM6B overexpression has the opposite effects. Mechanistically, KDM6B regulates TNFA_SIGNALING_VIA_NFκB signalling pathways, and H3K27me3 binds to the promoter region of C/EBPβ, leading to the promotion of C/EBPβ transcription. Besides, we show that GSK-J4, a chemical inhibitor of KDM6B, markedly inhibits proliferation and metastasis of ESCC cells.

Conclusions

The present study demonstrated that KDM6B promotes ESCC progression by increasing the transcriptional activity of C/EBPβ depending on its H3K27 demethylase activity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08282-w.

Upregulation of KDM6B contributes to lipopolysaccharide-induced anxiety-like behavior via modulation of VGLL4 in mice

Histone H3K27me3 demethylase KDM6B (also known as Jumonji domain-containing protein D3, JMJD3) plays vital roles in the etiology of inflammatory responses; however, little is known about the role of KDM6B in neuroinflammation-induced anxiety-like behavior. The present study aimed to investigate the potential role of KDM6B in lipopolysaccharide (LPS)-induced anxiety-like behavior and to evaluate whether it is associated with the modulation of vestigial-like family member 4 (VGLL4). The elevated plus maze, light-dark box, and open-field test were performed to test the anxiety-like behavior induced by LPS in C57BL/6 J male mice. Levels of relative protein expression in the hippocampus were quantified by western blotting. KDM6B inhibitor GSK-J4 and microglia inhibitor minocycline as well as adeno-associated virus of Vgll4 shRNA were used to explore the underlying mechanisms. We found that KDM6B, VGLL4, interleukin-1β (IL-1β), and ionized calcium-binding adaptor molecule-1 (Iba-1, microglia marker) protein levels were increased in LPS-dose dependent manner in the hippocampus but not in prefrontal cortex. GSK-J4 treatment attenuated LPS-induced VGLL4, the signal transducer and activator of transcription 3 (STAT3), IL-1β and Iba-1 upregulation and anxiety-like behavior. Knockdown VGLL4 with Vgll4 shRNA prevented the increase of anxiety-like behavior and levels of STAT3, IL-1β, and Iba-1 expression in the hippocampus of LPS-treated mice. Moreover, minocycline, an inhibitor of microglia treatment blunted LPS-induced anxiety-like behavior. Collectively, these results demonstrate that the induction of neuroinflammation by LPS promotes KDM6B activation in the hippocampus, and LPS-induced anxiety-like behavior is associated with upregulation of VGLL4 by KDM6B in the hippocampus.

KDM6B-mediated histone demethylation of LDHA promotes lung metastasis of osteosarcoma

Rationale: Osteosarcoma (OS), the most common type of bone tumor, which seriously affects the patients' limb function and life quality. OS has a strong tendency of lung metastasis, and the five-year survival rate of patients with metastatic osteosarcoma is less than 20%. Thus, new treatment targets and strategies are urgently needed.

Methods: The expression of the histone demethylase KDM6B and H3K27me3 levels in OS specimens were analyzed using quantitative PCR and immunohistochemical assays. The biological functions of KDM6B were determined using in vitro transwell, wound healing assays, and an in vivo orthotopic injection-induced lung metastasis model. Subsequently, chromatin immunoprecipitation sequencing (ChIP-seq) combined with transcriptomic RNA sequencing (RNA-seq), and subsequent ChIP-qPCR, western blot, and aerobic glycolysis assays were used to explore the mechanism of KDM6B function and validate the candidate target gene of KDM6B.

Results: KDM6B expression was significantly upregulated in OS patients, and high KDM6B expression was associated with poorer prognosis in OS patients. Targeting KDM6B significantly inhibited OS cell migration in vitro and lung metastasis in vivo. RNA-seq and ChIP-seq analysis revealed that KDM6B increases lactate dehydrogenase LDHA expression in OS cells by directly mediating H3K27me3 demethylation. The phenotypes of inhibited cell metastasis in KDM6B-knockdown OS cells was reversed upon overexpression of LDHA. Finally, a small molecule inhibitor targeting KDM6B significantly inhibited OS cell migration in vitro and lung metastasis in vivo.

Conclusions: Collectively, we elucidated that upregulated KDM6B facilitates tumor metastasis in OS via modulating LDHA expression. Our findings deepen the recognition of OS metastasis mechanism and suggest that KDM6B might be a new potential therapeutic target for the treatment of OS (especially highly metastatic OS).

Exosomal microRNA-22-3p alleviates cerebral ischemic injury by modulating KDM6B/BMP2/BMF axis

Background

Cerebral ischemia-reperfusion (I/R) injury, the most common form of stroke, has high mortality and often brings persistent and serious brain dysfunction among survivors. Administration of adipose-derived mesenchymal stem cells (ASCs) has been suggested to alleviate the I/R brain injury, but the mechanism remains uncharacterized. Here, we aimed at investigating the mechanism of ASCs and their extracellular vesicles (EVs) in the repair of or protection from I/R injury.

Methods

We established the middle cerebral artery occlusion (MCAO) model and oxygen-glucose deprivation/reperfusion (OGD/RP) neuron model. ASCs or ASC-derived EVs (ASC-EVs) were co-cultured with neurons. RT-qPCR and Western blot analyses determined microRNA (miRNA)-22-3p, BMP2, BMF, and KDM6B expression in neurons upon treatment with ASC-EVs. Bioinformatics analysis predicted the binding between miR-22-3p and KDM6B. Using gain- and loss-of-function methods, we tested the impact of these molecules on I/R injury in vivo and in vitro.

Results

Treatment with ASCs and ASC-derived EVs significantly alleviated the I/R brain injury in vivo, elevated neuron viability in vitro, and decreased apoptosis. Interestingly, miR-22-3p was upregulated in ASC-EVs, and treatment with EV-miR-22-3p inhibitor led to increased apoptosis and decreased neuronal. Of note, miR-22-3p bound to and inhibited KDM6B, as demonstrated by dual-luciferase reporter gene assay and Western blot assay. Overexpression of KDM6B enhanced apoptosis of neurons in the OGD/RP model, and KDM6B bound to BMB2 and promoted its expression by binding to BMP2. Silencing of BMF reduced infarct volume and apoptosis in the stroke model.

Conclusion

Results support a conclusion that ASC-EV-derived miR-22-3p could alleviate brain ischemic injury by inhibiting KDM6B-mediated effects on the BMP2/BMF axis. These findings compelling indicate a novel treatment strategy for cerebral ischemic injury.

The miRNA-15b/USP7/KDM6B axis engages in the initiation of osteoporosis by modulating osteoblast differentiation and autophagy

Osteoporosis is a metabolic disease that results from oxidative stress or inflammation in renal disorders. microRNAs (miRNAs) are recently implicated to participate in osteoporosis, but the mechanism remains largely unexplored. Herein, we aimed to explore the potential role of miR-15b in osteoblast differentiation and autophagy in osteoporosis. We established osteoporosis models through ovariectomy and determined that miR-15b was highly expressed whereas USP7 and KDM6B were poorly expressed in tissue of osteoporosis mice. Treatment of silenced miR-15b resulted in the elevation of decreased bone mineral density (BMD), the maximum elastic stress and the maximum load of osteoporosis mice. In osteoblasts, miR-15 overexpression decreased proliferation but suppressed the cell differentiation and autophagy, accompanied with decreased expression of USP7. Mechanistically, miR-15 bound and inhibited USP7 expression, while overexpression of USP7 promoted autophagy of osteoblasts. USP7, importantly, strengthened the stability of KDM6B and promoted KDM6B expression. MG132 protease inhibitor increased KDM6B and USP7 expression in osteoblasts. Silencing of KDM6B reversed the promoting effect on autophagy and proliferation induced by overexpression of USP7. Taken altogether, miR-15b inhibits osteoblast differentiation and autophagy to aggravate osteoporosis by targeting USP7 to regulate KDM6B expression.

Tumor-associated mesenchymal stem cells promote hepatocellular carcinoma metastasis via a DNM3OS/KDM6B/TIAM1 axis

Tumor-associated mesenchymal stem cells (MSCs) play a critical role in the growth and metastasis of hepatocellular carcinoma (HCC). However, the mechanism underlying the crosstalk between MSCs and HCC cells is not completely understood. Here, HCC cells were treated with or without conditioned medium of MSCs (CM-MSC), and examined for differential expression of long non-coding RNAs (lncRNAs). Knockdown and overexpression experiments were conducted to explore the function of the lncRNA DNM3OS in MSC-induced HCC growth and metastasis. CM-MSC treatment led to a concentration-dependent induction of DNM3OS in HCC cells. DNM3OS was significantly upregulated in HCC compared to adjacent liver tissues. High DNM3OS expression was associated with TNM stage, vascular invasion, and poor prognosis of HCC patients. Silencing of DNM3OS inhibited HCC cell proliferation and invasion in vitro and tumorigenesis and metastasis in vivo. Overexpression of DNM3OS enhanced HCC cell proliferation, invasion, and metastasis. Biochemically, DNM3OS was mainly localized in the nucleus and physically interacted with KDM6B. The association of DNM3OS with KDM6B induced the expression of TIAM1 through reduction of H3K27me3 at the TIAM1 promoter. TIAM1 overexpression restored the proliferation and invasion of DNM3OS-depleted HCC cells. Our data delineate a mechanism by which MSCs accelerate HCC growth and metastasis through a DNM3OS/KDM6B/TIAM1 axis.

Dysregulation of the histone demethylase KDM6B in alcohol dependence is associated with epigenetic regulation of inflammatory signaling pathways

Epigenetic enzymes oversee long‐term changes in gene expression by integrating genetic and environmental cues. While there are hundreds of enzymes that control histone and DNA modifications, their potential roles in substance abuse and alcohol dependence remain underexplored. A few recent studies have suggested that epigenetic processes could underlie transcriptomic and behavioral hallmarks of alcohol addiction. In the present study, we sought to identify epigenetic enzymes in the brain that are dysregulated during protracted abstinence as a consequence of chronic and intermittent alcohol exposure. Through quantitative mRNA expression analysis of over 100 epigenetic enzymes, we identified 11 that are significantly altered in alcohol‐dependent rats compared with controls. Follow‐up studies of one of these enzymes, the histone demethylase KDM6B, showed that this enzyme exhibits region‐specific dysregulation in the prefrontal cortex and nucleus accumbens of alcohol‐dependent rats. KDM6B was also upregulated in the human alcoholic brain. Upregulation of KDM6B protein in alcohol‐dependent rats was accompanied by a decrease of trimethylation levels at histone H3, lysine 27 (H3K27me3), consistent with the known demethylase specificity of KDM6B. Subsequent epigenetic (chromatin immunoprecipitation [ChIP]–sequencing) analysis showed that alcohol‐induced changes in H3K27me3 were significantly enriched at genes in the IL‐6 signaling pathway, consistent with the well‐characterized role of KDM6B in modulation of inflammatory responses. Knockdown of KDM6B in cultured microglial cells diminished IL‐6 induction in response to an inflammatory stimulus. Our findings implicate a novel KDM6B‐mediated epigenetic signaling pathway integrated with inflammatory signaling pathways that are known to underlie the development of alcohol addiction.

Pharmacological targeting of KDM6A and KDM6B, as a novel therapeutic strategy for treating craniosynostosis in Saethre-Chotzen syndrome

BACKGROUND

During development, excessive osteogenic differentiation of mesenchymal progenitor cells (MPC) within the cranial sutures can lead to premature suture fusion or craniosynostosis, leading to craniofacial and cognitive issues. Saethre-Chotzen syndrome (SCS) is a common form of craniosynostosis, caused by TWIST-1 gene mutations. Currently, the only treatment option for craniosynostosis involves multiple invasive cranial surgeries, which can lead to serious complications.

METHODS

The present study utilized Twist-1 haploinsufficient (Twist-1^del/+) mice as SCS mouse model to investigate the inhibition of Kdm6a and Kdm6b activity using the pharmacological inhibitor, GSK-J4, on calvarial cell osteogenic potential.

RESULTS

This study showed that the histone methyltransferase EZH2, an osteogenesis inhibitor, is downregulated in calvarial cells derived from Twist-1^del/+ mice, whereas the counter histone demethylases, Kdm6a and Kdm6b, known promoters of osteogenesis, were upregulated. In vitro studies confirmed that siRNA-mediated inhibition of Kdm6a and Kdm6b expression suppressed osteogenic differentiation of Twist-1^del/+ calvarial cells. Moreover, pharmacological targeting of Kdm6a and Kdm6b activity, with the inhibitor, GSK-J4, caused a dose-dependent suppression of osteogenic differentiation by Twist-1^del/+ calvarial cells in vitro and reduced mineralized bone formation in Twist-1^del/+ calvarial explant cultures. Chromatin immunoprecipitation and Western blot analyses found that GSK-J4 treatment elevated the levels of the Kdm6a and Kdm6b epigenetic target, the repressive mark of tri-methylated lysine 27 on histone 3, on osteogenic genes leading to repression of Runx2 and Alkaline Phosphatase expression. Pre-clinical in vivo studies showed that local administration of GSK-J4 to the calvaria of Twist-1^del/+ mice prevented premature suture fusion and kept the sutures open up to postnatal day 20.

CONCLUSION

The inhibition of Kdm6a and Kdm6b activity by GSK-J4 could be used as a potential non-invasive therapeutic strategy for preventing craniosynostosis in children with SCS. Pharmacological targeting of Kdm6a/b activity can alleviate craniosynostosis in Saethre-Chotzen syndrome. Aberrant osteogenesis by Twist-1 mutant cranial suture mesenchymal progenitor cells occurs via deregulation of epigenetic modifiers Ezh2 and Kdm6a/Kdm6b. Suppression of Kdm6a- and Kdm6b-mediated osteogenesis with GSK-J4 inhibitor can prevent prefusion of cranial sutures.

EZH2 and KDM6B Expressions Are Associated with Specific Epigenetic Signatures during EMT in Non Small Cell Lung Carcinomas

The role of Epigenetics in Epithelial Mesenchymal Transition (EMT) has recently emerged. Two epigenetic enzymes with paradoxical roles have previously been associated to EMT, EZH2 (Enhancer of Zeste 2 Polycomb Repressive Complex 2 (PRC2) Subunit), a lysine methyltranserase able to add the H3K27me3 mark, and the histone demethylase KDM6B (Lysine Demethylase 6B), which can remove the H3K27me3 mark. Nevertheless, it still remains unclear how these enzymes, with apparent opposite activities, could both promote EMT. In this study, we evaluated the function of these two enzymes using an EMT-inducible model, the lung cancer A549 cell line. ChIP-seq coupled with transcriptomic analysis showed that EZH2 and KDM6B were able to target and modulate the expression of different genes during EMT. Based on this analysis, we described INHBB, WTN5B, and ADAMTS6 as new EMT markers regulated by epigenetic modifications and directly implicated in EMT induction.

Regulating Methylation at H3K27: A Trick or Treat for Cancer Cell Plasticity

Properly timed addition and removal of histone 3 lysine 27 tri-methylation (H3K27me3) is critical for enabling proper differentiation throughout all stages of development and, likewise, can guide carcinoma cells into altered differentiation states which correspond to poor prognoses and treatment evasion. In early embryonic stages, H3K27me3 is invoked to silence genes and restrict cell fate. Not surprisingly, mutation or altered functionality in the enzymes that regulate this pathway results in aberrant methylation or demethylation that can lead to malignancy. Likewise, changes in expression or activity of these enzymes impact cellular plasticity, metastasis, and treatment evasion. This review focuses on current knowledge regarding methylation and de-methylation of H3K27 in cancer initiation and cancer cell plasticity.

Sodium lactate promotes stemness of human mesenchymal stem cells through KDM6B mediated glycolytic metabolism

Mesenchymal stem cells (MSCs) are an important cell source for tissue homeostasis and repair due to their stemness characteristic. Lots of intrinsic signaling pathways have been reported to regulate MSC stemness, but the extrinsic signals such as sodium lactate, particularly in physiological conditions, are poorly understood. Herein, we evaluated the effect of sodium lactate on human MSC stemness regulation by examining colony-forming ability, energy metabolism, multi-lineage differentiation ability, and pluripotent gene and protein expression. The underlying mechanism was further investigated with gene knockdown as well as small molecule interference and rescue experiments. We found that: (1) low concentration (1 mM) of sodium lactate promoted the stemness of human MSCs; (2) the upregulation of glycolysis was responsible for the MSC stemness promotion; (3) lysine demethylase 6B (KDM6B) was the key regulator which mediated sodium lactate-induced glycolysis and human MSC stemness enhancement. This study indicated that sodium lactate played an important role in human MSC stemness maintenance in physiological conditions, which could be related to KDM6B mediated metabolic regulation. It would provide new insight into stem cell biology, and contribute to cell transplantation and tissue regeneration strategies.

Puerarin 6″-O-xyloside suppressed HCC via regulating proliferation, stemness, and apoptosis with inhibited PI3K/AKT/mTOR

Puerarin 6″‐O‐xyloside is a tumor suppressive derivate of Puerarin that is recently characterized as a lysine‐specific demethylase 6B inhibitor. Here we investigated the effects of Puerarin 6″‐O‐xyloside in hepatocellular carcinoma (HCC) cell lines SMMC‐7721 and HepG2. Cell viability, proliferation, stemness, protein expression, and autophagy were tested by CCK‐8, colony formation, sphere formation, western blotting, and LC3B GFP puncta per cell, respectively. Apoptosis, CD133‐positive cells, and JC‐1‐labeled mitochondrial membrane potential were measured by flow cytometry. The effects of Puerarin 6″‐O‐xyloside in vivo were explored in HepG2 xenograft mice. Puerarin 6″‐O‐xyloside inhibited cell viability, proliferation, and stemness, and promoted apoptosis in both SMMC‐7721 and HepG2 cells. Further experiments showed promoted autophagy and decreased mitochondrial membrane potential, and decreased expression of p‐PI3K, p‐AKT, and p‐mTOR in HepG2 cells. Co‐administration of 3‐MA with Puerarin 6″‐O‐xyloside obviously augmented these effects including inhibited protein expression of p‐PI3K, p‐AKT, and p‐mTOR, and inhibited proliferation, promoted apoptosis, and decreased stemness. In HepG2 xenograft mice, 100 mg/kg/d Puerarin 6″‐O‐xyloside significantly suppressed tumor growth, stemness, and apoptosis. In conclusion, our study indicated that Puerarin 6″‐O‐xyloside decreased cell viability, proliferation, and stemness, and promoted autophagy and mitochondria‐dependent apoptosis of HCC, at least partly through inhibiting PI3K/AKT/mTOR. These results highlighted Puerarin 6″‐O‐xyloside as a promising prodrug that could inhibit both PI3K/AKT/mTOR and epigenetic demethylation.

Endothelial progenitor cells-secreted extracellular vesicles containing microRNA-93-5p confer protection against sepsis-induced acute kidney injury via the KDM6B/H3K27me3/TNF-α axis

The pivotal pathogenetic role of microRNAs (miRs) in sepsis-induced acute kidney injury (AKI) has been demonstrated in mounting evidence. The functions of the target cells are regulated through the release of cells-encapsulated extracellular vesicles (Evs) into the extracellular space. The present study aims to elucidate the clinical significance as well as biological function of the endothelial progenitor cell (EPC)-derived Evs containing miR-93-5p in sepsis-induced AKI. We first established a cellular sepsis-induced AKI mouse model by treatment with lipopolysaccharide (LPS), and tested ectopic expression and depletion experiments in the model. Evs derived from miR-93-5p inhibitor-transfected EPCs (Evs/miR-93-5p inhibitor) were isolated, and co-cultured with HK2 cells to explore the effects of EPC-derived Evs overexpressing miR-93-5p on LPS-induced HK2 cell injury. The interaction between miR-93-5p and lysine (K)-specific demethylase 6B (KDM6B) was identified using dual-luciferase reporter assay, and ChIP was used to validate the relationship between KDM6B and tumor necrosis factor-α (TNF-α). Mice were made septic by cecal ligation and puncture (CLP), and then injected with Ev/miR-93-5p inhibitor to explore its functions in vivo. The results found that miR-93-5p and histone H3 Lys27 trimethylation (H3K27me3) were downregulated while KDM6B was upregulated in LPS-treated HK2 cells. EPC-derived Evs alleviated LPS-induced HK2 cell injury, while Ev/miR-93-5p inhibitor potentiated the cell injury in vitro. miR-93-5p was found to directly target KDM6B. Silencing KDM6B induced H3K27me3, inhibiting the activation of TNF-α, thereby weakening LPS-induced HK2 cell injury. EPC-derived Evs containing miR-93-5p attenuated multiple organ injury, vascular leakage, inflammation, and apoptosis in septic mice. In conclusion, the present study demonstrated that endothelial protection from EPC-derived Evs carrying miR-93-5p in sepsis-induced AKI, which was mediated by regulation KDM6BH/3K27me3/TNF-α axis.

[Study on the Expression of KDM6B of Osteoblast in Diabetic Environment]

OBJECTIVE

To investigate the ability of osteogenic differentiation and the expression of histone demethylases KDM6B in bone marrow mesenchymal stem cells (BMSCs) in diabetic environment.

METHODS

Diabetic model rats was successfully established, and BMSCs from diabetic model rats and normal rats were isolated and cultured for further study. When cultured cells, we added high concentration of glucose and advanced glycosylation products (AGE) in the medium to imitating the diabetic environment. BMSCs were divided into 6 groups: diabetes group (derived from diabets SD rats), normal group (derived from normal SD rats), high glucose group (30 mmol/L D-glucose), normal glucose group (5.5 mmol/L D-glucose), AGE group (AGE 300 μg/mL) and BSA group (BSA 300 μg/mL). BMSCs in diabetes group were derived from diabetes SD rats, while others were derived from normal SD rats. After 7 d of osteogenic induction, the cells were examined the ability of osteogenic differentiation by alkaline phosphatase (ALP) staining, the transcription levels of Runt-related transcription factor 2 (Runx2) and KDM6B were determined by RT-PCR, and the expression levels of H3K27Me3 protein were examined by Western bolt.

RESULTS

Compared with the control groups, the numbers of ALP stained cells and the mRNA levels of Runx2 and KDM6B in diabetes group, high glucose group and AGE group were all decreased (P < 0.05), while H3K27Me3 protein expression levels were all increased (P < 0.05).

CONCLUSION

The ability of osteogenic differentiation of BMSCs in diabetic environment was weakened, and the expression of Runx2 mRNA was inhibited, which may be related to the increased expression of H3K27Me3 after the inhibition of KDM6B expression.

Histone demethylase KDM6B regulates human podocyte differentiation in vitro

Podocytes are terminally differentiated and highly specialized glomerular cells, which have an essential role as a filtration barrier against proteinuria. Histone methylation has been shown to influence cell development, but its role in podocyte differentiation is less understood. In this study, we first examined the expression pattern of histone demethylase KDM6B at different times of cultured human podocytes in vitro We found that the expression of KDM6B and podocyte differentiation markers WT1 and Nephrin are increased in the podocyte differentiation process. In cultured podocytes, KDM6B knockdown with siRNA impaired podocyte differentiation and led to expression down-regulation of WT1 and Nephrin. The treatment of podocytes with GSK-J4, a specific KDM6B inhibitor, can also obtain similar results. Overexpression of WT1 can rescue differentiated phenotype impaired by disruption of KDM6B ChIP (chromatin immunoprecipitation) assay further indicated that KDM6B can bind the promoter region of WT1 and reduce the histone H3K27 methylation. Podocytes in glomeruli from nephrotic patients exhibited increased KDM6B contents and reduced H3K27me3 levels. These data suggest a role for KDM6B as a regulator of podocyte differentiation, which is important for the understanding of podocyte function in kidney development and related diseases.

Targeting of Histone Demethylases KDM5A and KDM6B Inhibits the Proliferation of Temozolomide-Resistant Glioblastoma Cells

Lysine histone demethylases (KDMs) are considered potential therapeutic targets in several tumors, including glioblastoma (GB). In particular, KDM5A is involved in the acquisition of temozolomide (TMZ) resistance in adult GB cells and UDX/KDM6B regulates H3K27 methylation, which is involved in the pediatric diffuse intrinsic pontine glioma (DIPG). Synthetic inhibitors of KDM5A (JIB 04 and CPI-455) efficiently block the proliferation of native and TMZ-resistant cells and the KDM6B inhibitor GSK J4 improves survival in a model of DIPG. The aim of our work was to determine if GSK J4 could be effective against GB cells that have acquired TMZ resistance and if it could synergize with TMZ or JIB 04 to increase the clinical utility of these molecules. Standard functional and pharmacological analytical procedures were utilized to determine the efficacy of the molecules under study when used alone or in combination against native GB cells and in a model of drug resistance. The results of this study indicated that although GSK J4 is active against native and TMZ-resistant cells, it does so at a lower efficacy than JIB 04. Drug combination studies revealed that GSK J4, differently from JIB 04, does not synergize with TMZ. Interestingly, GSK J4 and JIB 04 strongly synergize and are a potent combination against TMZ-resistant cells. Further studies in animal models will be necessary to determine if this combination of molecules might foster the development of novel therapeutic approaches for glioblastoma.

Genetic variants in the KDM6B gene are associated with neurodevelopmental delays and dysmorphic features

Lysine-specific demethylase 6B (KDM6B) demethylates trimethylated lysine-27 on histone H3. The methylation and demethylation of histone proteins affects gene expression during development. Pathogenic alterations in histone lysine methylation and demethylation genes have been associated with multiple neurodevelopmental disorders. We have identified a number of de novo alterations in the KDM6B gene via whole exome sequencing (WES) in a cohort of 12 unrelated patients with developmental delay, intellectual disability, dysmorphic facial features, and other clinical findings. Our findings will allow for further investigation in to the role of the KDM6B gene in human neurodevelopmental disorders.

Elevated H3K27me3 levels sensitize osteosarcoma to cisplatin

BACKGROUND

In osteosarcoma (OS), chemotherapy resistance has become one of the greatest issues leading to high mortality among patients. However, the mechanisms of drug resistance remain elusive, limiting therapeutic efficacy. Here, we set out to explore the relationship between dynamic histone changes and the efficacy of cisplatin against OS.

RESULTS

First, we found two histone demethylases associated with histone H3 lysine 27 trimethylation (H3K27me3) demethylation, KDM6A, and KDM6B that were upregulated after cisplatin treatment. Consistent with the clinical data, cisplatin-resistant OS specimens showed lower H3K27me3 levels than sensitive specimens. Then, we evaluated the effects of H3K27me3 alteration on OS chemosensitivity. In vitro inhibition of the histone methyltransferase EZH2 in OS cells decreased H3K27me3 levels and led to cisplatin resistance. Conversely, inhibition of the demethylases KDM6A and KDM6B increased H3K27me3 levels in OS and reversed cisplatin resistance in vitro and in vivo. Mechanistically, with the help of RNA sequencing (RNAseq), we found that PRKCA and MCL1 directly participated in the process by altering H3K27me3 on their gene loci, ultimately inactivating RAF/ERK/MAPK cascades and decreasing phosphorylation of BCL2.

CONCLUSIONS

Our study reveals a new epigenetic mechanism of OS resistance and indicates that elevated H3K27me3 levels can sensitize OS to cisplatin, suggesting a promising new strategy for the treatment of OS.

The histone H3 Lys 27 demethylase KDM6B promotes migration and invasion of glioma cells partly by regulating the expression of SNAI1

The histone demethylase KDM6B, also known as jumonji domain-containing protein 3 (JMJD3), is an epigenetic regulator which plays important roles in immune activation, tissue regeneration, cellular senescence and cancer metastasis. But, the role of KDM6B in glioma metastasis is poorly understood. In this study, we achieved transcriptional regulation of KDM6B in glioma cells using CRISPR interference (CRISPRi) and CRISPR activation (CRISPRa). Our results showed that KDM6B promotes the proliferation, migration and invasion of human glioblastoma cells U87 and U251 using CCK8, scratch and transwell assays. Further results indicated that KDM6B increases the expression of SNAI1, a key factor of epithelial-mesenchymal transition (EMT). KDM6B catalyzes the demethylation of histone H3 Lys 27 trimethylation (H3K27me3) in the promoter of SNAI1, which is important for SNAI1 upregulation. Taken together, these findings provide new insight into the mechanism by which KDM6B promotes glioma metastasis.

Epigenetic Regulation of EMT (Epithelial to Mesenchymal Transition) and Tumor Aggressiveness: A View on Paradoxical Roles of KDM6B and EZH2

EMT (epithelial to mesenchymal transition) is a plastic phenomenon involved in metastasis formation. Its plasticity is conferred in a great part by its epigenetic regulation. It has been reported that the trimethylation of lysine 27 histone H3 (H3K27me3) was a master regulator of EMT through two antagonist enzymes that regulate this mark, the methyltransferase EZH2 (enhancer of zeste homolog 2) and the lysine demethylase KDM6B (lysine femethylase 6B). Here we report that EZH2 and KDM6B are overexpressed in numerous cancers and involved in the aggressive phenotype and EMT in various cell lines by regulating a specific subset of genes. The first paradoxical role of these enzymes is that they are antagonistic, but both involved in cancer aggressiveness and EMT. The second paradoxical role of EZH2 and KDM6B during EMT and cancer aggressiveness is that they are also inactivated or under-expressed in some cancer types and linked to epithelial phenotypes in other cancer cell lines. We also report that new cancer therapeutic strategies are targeting KDM6B and EZH2, but the specificity of these treatments may be increased by learning more about the mechanisms of action of these enzymes and their specific partners or target genes in different cancer types.

KDM6A and KDM6B play contrasting roles in nuclear transfer embryos revealed by MERVL reporter system

Despite the success of animal cloning by somatic cell nuclear transfer (SCNT) in many species, the method is limited by its low efficiency. After zygotic genome activation (ZGA) during mouse development, a large number of endogenous retroviruses (ERVs) are expressed, including the murine endogenous retrovirus‐L (MuERVL/MERVL). In this study, we generate a series of MERVL reporter mouse strains to detect the ZGA event in embryos. We show that the majority of SCNT embryos do not undergo ZGA, and H3K27me3 prevents SCNT reprogramming. Overexpression of the H3K27me3‐specific demethylase KDM6A, but not of KDM6B, improves the efficiency of SCNT. Conversely, knockdown of KDM6B not only facilitates ZGA, but also impedes ectopic Xist expression in SCNT reprogramming. Furthermore, knockdown of KDM6B increases the rate of SCNT‐derived embryonic stem cells from Duchenne muscular dystrophy embryos. These results not only provide insight into the mechanisms underlying failures of SCNT, but also may extend the applications of SCNT.

The histone demethylase KDM6B in the medial prefrontal cortex epigenetically regulates cocaine reward memory

Epigenetic remodeling contributes to synaptic plasticity via modification of gene expression, which underlies cocaine-induced long-term memory. A prevailing hypothesis in drug addiction is that drugs of abuse rejuvenate developmental machinery to render reward circuitry highly plastic and thus engender drug memories to be highly stable. Identification and reversal of these pathological pathways are therefore critical for cocaine abuse treatment. Previous studies revealed an interesting finding in which the mRNA of histone lysine demethylase, KDM6B, is upregulated in the medial prefrontal cortex (mPFC) during early cocaine withdrawal. However, whether and how it contributes to drug-seeking behavior remain unknown. Here we used a conditioned place preference paradigm to investigate the potential role of KDM6B in drug-associated memory. We found that KDM6B protein levels selectively increased in the mPFC during cocaine withdrawal. Notably, systemic injection of KDM6B inhibitor, GSK-J4, disrupted both reconsolidation of cocaine-conditioned memory and cocaine-primed reinstatement, suggesting dual effects of KDM6B in cocaine reward memory. In addition, we found that NMDAR expression and function were both enhanced during early cocaine withdrawal in mPFC. Injection of GSK-J4 selectively reversed this cocaine-induced increase of NR2A expression and synaptic function, suggesting that mal-adaptation of cocaine-induced synaptic plasticity in mPFC largely underlies KDM6B-mediated cocaine-associated memory. Altogether, these data suggest that KDM6B plays an essential role in cocaine-associated memory, which mainly acts through enhancing cocaine-induced synaptic plasticity in the mPFC. Our findings revealed a novel role of KDM6B in cocaine-associated memory and inhibition of KDM6B is a potential strategy to alleviate drug-seeking behavior.

KDM6B promotes ovarian cancer cell migration and invasion by induced transforming growth factor-β1 expression

KDM6B, also known as JMJD3, is a member of the family of histone lysine demethylase (KDMs), which is closely related to many types of cancers. However, its role and the underlying mechanisms in ovarian cancer remain unknown. Here we show that KDM6B is elevated in epithelial ovarian cancer and its expression level is closely related with metastasis and invasion. In addition, survival analysis showed that high expression of KDM6B was associated with low overall survival in ovarian cancer patients. Overexpression of KDM6B in epithelial ovarian cancer cells promoted proliferation, epithelial-mesenchymal transition (EMT), migration and invasion in vitro, and enhanced metastatic capacities in vivo. On the contrary, silencing KDM6B in invasive and metastatic ovarian cancer cells inhibited these processes. Mechanistically, we found that KDM6B exerts its function by modulating the transforming growth factor-β1 (TGF-β1) expression, and TGF-β1 signal pathway inhibitor LY2157299 significantly inhibited KDM6B-induced proliferation, migration, metastasis, and EMT in ovarian cancer cells. Our findings, for the first time, reveal the pivotal role of KDM6B in the invasion and metastatic behavior of epithelial ovarian cancer. Thus, targeting KDM6B may be a useful strategy to interfere with these behaviors of epithelial ovarian cancer.

AURKA Suppresses Leukemic THP-1 Cell Differentiation through Inhibition of the KDM6B Pathway

Aberrations in histone modifications are being studied in mixed-lineage leukemia (MLL)-AF9-driven acute myeloid leukemia (AML). In this study, we focused on the regulation of the differentiation of the MLL-AF9 type AML cell line THP-1. We observed that, upon phorbol 12-myristate 13-acetate (PMA) treatment, THP-1 cells differentiated into monocytes by down-regulating Aurora kinase A (AURKA), resulting in a reduction in H3S10 phosphorylation. We revealed that the AURKA inhibitor alisertib accelerates the expression of the H3K27 demethylase KDM6B, thereby dissociating AURKA and YY1 from the KDM6B promoter region. Using Flow cytometry, we found that alisertib induces THP-1 differentiation into monocytes. Furthermore, we found that treatment with the KDM6B inhibitor GSK-J4 perturbed the PMA-mediated differentiation of THP-1 cells. Thus, we discovered the mechanism of AURKA-KDM6B signaling that controls the differentiation of THP-1 cells, which has implications for biotherapy for leukemia.

Therapeutic potential of GSK-J4, a histone demethylase KDM6B/JMJD3 inhibitor, for acute myeloid leukemia

PURPOSE

Acute myeloid leukemia (AML) is a heterogeneous disease with poor outcomes. Despite increased evidence shows that dysregulation of histone modification contributes to AML, specific drugs targeting key histone modulators are not applied in the clinical treatment of AML. Here, we investigated whether targeting KDM6B, the demethylase of tri-methylated histone H3 lysine 27 (H3K27me3), has a therapeutic potential for AML.

METHODS

A KDM6B-specific inhibitor, GSK-J4, was applied to treat the primary cells from AML patients and AML cell lines in vitro and in vivo. RNA-sequencing was performed to reveal the underlying mechanisms of inhibiting KDM6B for the treatment of AML.

RESULTS

Here we observed that the mRNA expression of KDM6B was up-regulated in AML and positively correlated with poor survival. Treatment with GSK-J4 increased the global level of H3K27me3 and reduced the proliferation and colony-forming ability of primary AML cells and AML cell lines. GSK-J4 treatment significantly induced cell apoptosis and cell-cycle arrest in Kasumi-1 cells, and displayed a synergistic effect with cytosine arabinoside. Notably, injection of GSK-J4 attenuated the disease progression in a human AML xenograft mouse model in vivo. Treatment with GSK-J4 predominantly resulted in down-regulation of DNA replication and cell-cycle-related pathways, as well as abrogated the expression of critical cancer-promoting HOX genes. ChIP-qPCR validated an increased enrichment of H3K27me3 in the transcription start sites of these HOX genes.

CONCLUSIONS

In summary, our findings suggest that targeting KDM6B with GSK-J4 has a therapeutic potential for the treatment of AML.

MicroRNA-99a is a novel regulator of KDM6B-mediated osteogenic differentiation of BMSCs

Skeletal tissue originates from mesenchymal stem cells (MSCs) with differentiation potential into the osteoblast lineage regulated by essential transcriptional and post‐transcriptional mechanisms. Recently, miRNAs and histone modifications have been identified as novel key regulators of osteogenic differentiation of MSCs. Here, we identified miR‐99a and its target lysine (K)‐specific demethylase 6B (KDM6B) gene as novel modulators of osteogenic differentiation of bone mesenchymal stem cells (BMSCs). Microarray profiling and further validation by quantitative real‐time RT‐PCR revealed that miR‐99a was up‐regulated during osteoblastic differentiation of BMSCs, and decreased in differentiated osteoblasts. Transfection of miR‐99a mimics inhibited osteoblastic commitment and differentiation of BMSCs, whereas inhibition of miR‐99a by inhibitors enhances these processes. KDM6B was determined as one of important targets of miR‐99a, which was further confirmed by luciferase assay of 3′‐UTR of KDM6B. Moreover, HOX gene level decreased after transfection of miR‐99a mimics in BMSCs, which indicated that KDM6B is a bona fide target of miR‐99a. Furthermore, in a model of in vivo bone regeneration, osteoblast‐specific gain‐ and loss‐of‐function experiments performed using cranial bone defects revealed that miR‐99a mimics‐transfected BMSCs reduced bone formation, and conversely, miR‐99a inhibitors‐transfected BMSCs increased in vivo bone formation. Tissue‐specific inhibition of miR‐99a may be a potential novel therapeutic approach for enhancing BMSCs‐based bone formation and regeneration.

A Determined "Hesitation" on H3K27me3 Empowers Stem Cells to Differentiate

To uncover the precise mechanisms coordinating proliferation and fate choice of stem cells, in this issue of Molecular Cell and in an accompanying paper in Cell Reports, Mazo and colleagues (Petruk et al. 2017a, 2017b) reveal that delayed accumulation of H3K27me3 on nascent DNA is essential to recruit pioneer transcription factors in stem cell differentiation.

Local application of IGFBP5 protein enhanced periodontal tissue regeneration via increasing the migration, cell proliferation and osteo/dentinogenic differentiation of mesenchymal stem cells in an inflammatory niche

Background

Periodontitis is a widespread infectious disease ultimately resulting in tooth loss. The number of mesenchymal stem cells (MSCs) in patients with periodontitis is decreased, and MSC functions are impaired. Rescuing the impaired function of MSCs in periodontitis is the key for treatment, especially in a manner independent of exogenous MSCs. Our previous study found that overexpressed insulin-like growth factor binding protein 5 (IGFBP5) could promote exogenous MSC-mediated periodontal tissue regeneration. Here, we investigate the role of IGFBP5 protein in MSCs and periodontal tissue regeneration independent of exogenous MSCs in an inflammatory niche.

Methods

TNFα was used to mimic the inflammatory niche. Lentiviral IGFBP5 shRNA was used to silence IGFBP5 and recombinant human IGFBP5 protein (rhIGFBP5) was used to stimulate the periodontal ligament stem cells (PDLSCs) and bone marrow stem cells (BMSCs). The effects of IGFBP5 on PDLSCs were evaluated using the scratch-simulated wound migration, Transwell chemotaxis, alkaline phosphatase (ALP) activity, Alizarin red staining, Cell Counting Kit-8, Western blot, Real-time PCR, Co-IP and ChIP assays. The swine model of periodontitis was used to investigate the functions of IGFBP5 for periodontal regeneration and its anti-inflammation effect.

Results

We discovered that 0.5 ng/ml rhIGFBP5 protein enhanced the migration, chemotaxis, osteo/dentinogenic differentiation and cell proliferation of MSCs under the inflammatory condition. Moreover, 0.5 ng/ml rhIGFBP5 application could rescue the impaired functions of IGFBP5-silenced-MSCs in the inflammatory niche. Furthermore, local injection of rhIGFBP5 could promote periodontal tissue regeneration and relieve the local inflammation in a minipig model of periodontitis. Mechanistically, we found that BCOR negatively regulated the expression of IGFBP5 in MSCs. BCOR formed a protein complex with histone demethylase KDM6B and raised histone K27 methylation in the IGFBP5 promoter.

Conclusions

This study revealed that rhIGFBP5 could activate the functions of MSCs in an inflammatory niche, provided insight into the mechanism underlying the activated capacities of MSCs, and identified IGFBP5 as a potential cytokine for improving tissue regeneration and periodontitis treatment independent of exogenous MSCs and its potential application in dental clinic.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0663-6) contains supplementary material, which is available to authorized users.

Bivalent Histone Codes on WNT5A during Odontogenic Differentiation

Lineage-committed differentiation is an essential biological program during odontogenesis, which is tightly regulated by lineage-specific genes. Some of these genes are modified by colocalization of H3K4me3 and H3K27me3 marks at promoter regions in progenitors. These modifications, named "bivalent domains," maintain genes in a poised state and then resolve for later activation or repression during differentiation. Wnt5a has been reported to promote odontogenic differentiation in dental mesenchyme. However, relatively little is known about the epigenetic modulations on Wnt5a activation during tooth development. Here, we investigated the spatiotemporal patterns of H3K4me3 and H3K27me3 marks in developing mouse molars. Associated H3K4me3 methylases (mixed-lineage leukemia [MLL] complex) and H3K27me3 demethylases (JMJD3 and UTX) were dynamically expressed between early and late bell stage of human tooth germs and in cultured human dental papilla cells (hDPCs) during odontogenic induction. Poised WNT5A gene was marked by bivalent domains containing repressive marks (H3K27me3) and active marks (H3K4me3) on promoters. The bivalent domains tended to resolve during inducted differentiation, with removal of the H3K27me3 mark in a JMJD3-dependent manner. When JMJD3 was knocked down in cultured hDPCs, odontogenic differentiation was suppressed. The depletion of JMJD3 epigenetically repressed WNT5A activation by increased H3K27me3 marks. In addition, JMJD3 could physically interact with ASH2L, a component of the MLL complex, to form a coactivator complex, cooperatively modulating H3K4me3 marks on WNT5A promoters. Overall, our study reveals that transcription activities of WNT5A were epigenetically regulated by the negotiated balance between H3K27me3 and H3K4me3 marks and tightly mediated by JMJD3 and MLL coactivator complex, ultimately modulating odontogenic commitment during dental mesenchymal cell differentiation.