BACKGROUND: Knee osteoarthritis (OA) is still challenging to prevent or treat. Enhanced endoplasmic reticulum (ER) stress and increased pyroptosis in chondrocytes may be responsible for cartilage degeneration. This study aims to investigate the effect of ER stress on chondrocyte pyroptosis and the upstream regulatory mechanisms, which have rarely been reported. METHODS: The expression of the histone methyltransferase enhancer of zeste homolog 2 (EZH2), microRNA-142-3p (miR-142-3p), and high mobility group box 1 (HMGB1) and the levels of ER stress, pyroptosis, and metabolic markers in normal and OA chondrocytes were investigated by western blotting, quantitative polymerase chain reaction, immunohistochemistry, fluorescence in situ hybridization, fluorescein amidite-tyrosine-valine-alanine-aspartic acid-fluoromethyl ketone (FAM-YVAD-FMK)/Hoechst 33342/propidium iodide (PI) staining, lactate dehydrogenase (LDH) release assays, and cell viability assessments. The effects of EZH2, miR-142-3p, and HMGB1 on ER stress and pyroptosis and the hierarchical regulatory relationship between them were analyzed by chromatin immunoprecipitation, luciferase reporters, gain/loss-of-function assays, and rescue assays in interleukin (IL)-1β-induced OA chondrocytes. The mechanistic contribution of EZH2, miR-142-3p, and HMGB1 to chondrocyte ER stress and pyroptosis and therapeutic prospects were validated radiologically, histologically, and immunohistochemically in surgically induced OA rats. RESULTS: Increased EZH2 and HMGB1, decreased miR-142-3p, enhanced ER stress, and activated pyroptosis in chondrocytes were associated with OA occurrence and progression. EZH2 and HMGB1 exacerbated and miR-142-3p alleviated ER stress and pyroptosis in OA chondrocytes. EZH2 transcriptionally silenced miR-142-3p via H3K27 trimethylation, and miR-142-3p posttranscriptionally silenced HMGB1 by targeting the 3'-UTR of the HMGB1 gene. Moreover, ER stress mediated the effects of EZH2, miR-142-3p, and HMGB1 on chondrocyte pyroptosis. In vivo experiments mechanistically validated the hierarchical regulatory relationship between EZH2, miR-142-3p, and HMGB1 and their effects on chondrocyte ER stress and pyroptosis. CONCLUSIONS A novel EZH2/miR-142-3p/HMGB1 axis mediates chondrocyte pyroptosis and cartilage degeneration by regulating ER stress in OA, contributing novel mechanistic insights into OA pathogenesis and providing potential targets for future therapeutic research.
Enhancer of Zeste Homolog 2 Protein/genetics* ; Osteoarthritis, Knee/pathology* ; Chondrocytes/metabolism* ; Pyroptosis/physiology* ; HMGB1 Protein/genetics* ; MicroRNAs/metabolism* ; Endoplasmic Reticulum Stress/genetics* ; Humans ; Animals ; Rats ; Male ; Rats, Sprague-Dawley ; Middle Aged

OBJECTIVE: To investigate the expression levels of EZH2 and KMT2D in patients with diffuse large B-cell lymphoma (DLBCL) and their relationship with pathological features. METHODS: 84 patients with DLBCL treated in our hospital from January 2021 to June 2022 were selected as the study subjects, and clinical characteristics such as sex, age and pathological classification of the patients were collected. Immunohistochemistry was used to detecet the expression of KMT2D and EZH2 proteins in tumor tissue cells of the DLBCL patients. The differential expression of KMT2D and EZH2 in subgroups of different sexes, ages, primary sites, clinical stages, Hans subtypes, etc. were compared. The correlation between the expression of KMT2D and EZH2 protein and BCL-6, CD79A was analyzed and validated through the interaction of protein molecular structures. We followed up and recorded the survival status of the patients for 12 months, and analyzed the factors that affect the mortality of DLBCL patients. RESULTS: The positive rate of KMT2D and EZH2 was high (over 95%) in DLBCL patients. There was no significant difference in the expression of EZH2 and KMT2D among subgroups of different sexes, ages and stages (P >0.05). However, patients with different levels of BCL-6 and CD79A expression showed differences in EZH2 and KMT2D expression (P < 0.05). EZH2 and KMT2D were positively correlated with BCL-6 (r =0.391, r =0.332) and CD79A (r =0.309, r =0.258), respectively, and there were interactions in the protein molecular structures. The risk factors for mortality in DLBCL patients include male sex (OR =1.106, 95%CI : 1.082-1.130, P < 0.001), stage II (OR =1.778, 95%CI : 1.567-2.016, P < 0.001), stage IV (OR =2.233, 95%CI : 2.021-2.467, P < 0.001), EZH2 positive (OR =2.762, 95%CI : 1.304-5.850, P =0.008), BCL-6 positive (OR =7.309, 95%CI : 1.340-39.859, P =0.022), age≥74 years (OR =3.080, 95%CI : 1.658-5.723, P < 0.001), and 63-73 years old (OR =2.400, 95%CI : 1.564-3.682, P < 0.001), while KMT2D positive (OR =0.180, 95%CI : 0.054-0.608, P =0.006) and 41-51 years old (OR =0.406, 95%CI : 0.274-0.603, P < 0.001) were factors which could reduce the risk of mortality. CONCLUSION EZH2 and KMT2D are highly expressed in patients with DLBCL, and they are positively correlated with BCL-6 and CD79A, and affect the prognosis of DLBCL patients.
Humans ; Enhancer of Zeste Homolog 2 Protein/metabolism* ; Lymphoma, Large B-Cell, Diffuse/metabolism* ; DNA-Binding Proteins/metabolism* ; Female ; Male ; Middle Aged ; Adult ; Neoplasm Proteins/metabolism* ; Aged ; Immunohistochemistry ; Proto-Oncogene Proteins c-bcl-6/metabolism* ; Prognosis

OBJECTIVES: Esophageal squamous cell carcinoma (ESCC) is characterized by complex pathogenesis and poor prognosis. In recent years, epithelial-mesenchymal transition (EMT) in tumor initiation and progression has attracted increasing attention. Enhancer of zeste homolog 2 (EZH2), which is aberrantly expressed in various tumors, may be closely related to the EMT process. This study aims to examine the expression and correlation of EZH2 and EMT markers in ESCC cells and tissues, evaluate the effects of EZH2 knockdown on ESCC cell proliferation, invasion, and migration, and explore how EZH2 contributes to the malignant biological behavior of ESCC. METHODS: Bioinformatics analyses were used to assess EZH2 expression levels in ESCC. Small interfering RNA was used to knock down EZH2 in ESCC cell lines EC109 and EC9706. Cell proliferation, invasion, and migration were evaluated using cell counting kit-8 (CCK-8), wound healing, and Transwell assays. Protein and mRNA expression levels of EZH2, E-cadherin (E-cad), and vimentin (Vim) were detected by Western blotting and real time fluorogenic quantitative PCR (RT-qPCR), respectively. Immunohistochemical (IHC) staining was performed on 70 ESCC tissue samples and 40 paired adjacent normal tissues collected from the First Affiliated Hospital of Shihezi University between 2010 and 2016 to assess the expression of EZH2, E-cad, and Vim, and to analyze their associations with clinicopathological feature and patient prognosis. RESULTS: Bioinformatics analysis showed that EZH2 was highly expressed in ESCC (P<0.001), and high EZH2 expression was associated with worse prognosis (P<0.001). CCK-8, wound healing, and Transwell assays demonstrated that EZH2 knockdown significantly suppressed the proliferation, invasion, and migration of ESCC cells (P<0.001). In addition, Vim expression was significantly reduced, while E-cad expression was significantly increased at both protein and mRNA levels in EZH2-silenced cells (all P<0.05). IHC staining analysis revealed higher expression of EZH2 and Vim and lower expression of E-cad in ESCC tissues compared to adjacent normal tissues. Kaplan-Meier survival analysis showed that low expression of EZH2 and Vim and high expression of E-cad were associated with longer survival (all P<0.05). CONCLUSIONS EZH2 promotes malignant biological behavior in ESCC by mediating EMT. Elevated EZH2 expression is associated with poor prognosis in ESCC patients.
Humans ; Enhancer of Zeste Homolog 2 Protein/physiology* ; Esophageal Squamous Cell Carcinoma/pathology* ; Epithelial-Mesenchymal Transition/genetics* ; Esophageal Neoplasms/metabolism* ; Cell Proliferation ; Cell Line, Tumor ; Cell Movement ; Cadherins/genetics* ; Vimentin/genetics* ; Male ; Female ; Middle Aged ; Neoplasm Invasiveness ; Prognosis ; RNA, Small Interfering/genetics* ; Gene Expression Regulation, Neoplastic

Tissue formation and organ homeostasis are achieved by precise coordination of proliferation and differentiation of stem cells and progenitors. While deregulation of these processes can result in degenerative disease or cancer, their molecular interplays remain unclear. Here we show that the switch of human pluripotent stem cell (hPSC) self-renewal to differentiation is associated with the induction of distinct cyclin-dependent kinase inhibitors (CDKIs). In hPSCs, Activin/Nodal/TGFβ signaling maintains CDKIs in a poised state via SMAD2/3-NANOG-OCT4-EZH2-SNON transcriptional complex. Upon gradual differentiation, CDKIs are induced by successive transcriptional complexes between SMAD2/3-SMYD2 and developmental regulators such as EOMES, thereby lengthening the G1 phase. This, in turn, induces SMAD2/3 transcriptional activity by blocking its linker phosphorylation. Such SMAD2/3-CDKI positive feedback loops drive the exit from pluripotency and stepwise cell-fate specification that could be harnessed for producing cells for therapeutic applications. Our study uncovers fundamental mechanisms of how cell-fate specification is interconnected to cell-cycle dynamics and provides insight into autonomous circuitries governing tissue self-formation.
Humans ; Smad2 Protein/genetics* ; Smad3 Protein/genetics* ; Cell Differentiation ; Pluripotent Stem Cells/metabolism* ; Signal Transduction ; Octamer Transcription Factor-3/genetics* ; Enhancer of Zeste Homolog 2 Protein/genetics* ; Nanog Homeobox Protein/genetics* ; Phosphorylation

Humans ; Cardiovascular Diseases ; Enhancer of Zeste Homolog 2 Protein/metabolism* ; Histones ; Methyltransferases

Humans ; Cardiovascular Diseases ; Enhancer of Zeste Homolog 2 Protein/metabolism* ; Histones ; Methyltransferases

The histone methyltransferase enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2)-mediated trimethylation of histone H3 lysine 27 (H3K27me3) regulates neural stem cell proliferation and fate specificity through silencing different gene sets in the central nervous system. Here, we explored the function of EZH2 in early post-mitotic neurons by generating a neuron-specific Ezh2 conditional knockout mouse line. The results showed that a lack of neuronal EZH2 led to delayed neuronal migration, more complex dendritic arborization, and increased dendritic spine density. Transcriptome analysis revealed that neuronal EZH2-regulated genes are related to neuronal morphogenesis. In particular, the gene encoding p21-activated kinase 3 (Pak3) was identified as a target gene suppressed by EZH2 and H3K27me3, and expression of the dominant negative Pak3 reversed Ezh2 knockout-induced higher dendritic spine density. Finally, the lack of neuronal EZH2 resulted in impaired memory behaviors in adult mice. Our results demonstrated that neuronal EZH2 acts to control multiple steps of neuronal morphogenesis during development, and has long-lasting effects on cognitive function in adult mice.
Animals ; Mice ; Enhancer of Zeste Homolog 2 Protein/metabolism* ; Histone Methyltransferases/metabolism* ; Histones/genetics* ; Morphogenesis ; Neuronal Plasticity ; Neurons/metabolism*

N-methyladenosine (mA), catalyzed by the methyltransferase complex consisting of Mettl3 and Mettl14, is the most abundant RNA modification in mRNAs and participates in diverse biological processes. However, the roles and precise mechanisms of mA modification in regulating neuronal development and adult neurogenesis remain unclear. Here, we examined the function of Mettl3, the key component of the complex, in neuronal development and adult neurogenesis of mice. We found that the depletion of Mettl3 significantly reduced mA levels in adult neural stem cells (aNSCs) and inhibited the proliferation of aNSCs. Mettl3 depletion not only inhibited neuronal development and skewed the differentiation of aNSCs more toward glial lineage, but also affected the morphological maturation of newborn neurons in the adult brain. mA immunoprecipitation combined with deep sequencing (MeRIP-seq) revealed that mA was predominantly enriched in transcripts related to neurogenesis and neuronal development. Mechanistically, mA was present on the transcripts of histone methyltransferase Ezh2, and its reduction upon Mettl3 knockdown decreased both Ezh2 protein expression and consequent H3K27me3 levels. The defects of neurogenesis and neuronal development induced by Mettl3 depletion could be rescued by Ezh2 overexpression. Collectively, our results uncover a crosstalk between RNA and histone modifications and indicate that Mettl3-mediated mA modification plays an important role in regulating neurogenesis and neuronal development through modulating Ezh2.
Adenosine ; analogs & derivatives ; metabolism ; Adult Stem Cells ; cytology ; metabolism ; Animals ; Brain ; metabolism ; Cell Differentiation ; genetics ; Cell Proliferation ; Enhancer of Zeste Homolog 2 Protein ; metabolism ; Gene Expression Regulation ; Methyltransferases ; metabolism ; Mice, Inbred C57BL ; Neural Stem Cells ; cytology ; metabolism ; Neurogenesis ; genetics ; Neurons ; cytology ; metabolism ; RNA, Messenger ; genetics ; metabolism

BACKGROUND: It has been proven that CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated 9) system was the modern gene-editing technology through the constitutive expression of nucleases Cas9 in the mammalian, which binds to the specific site in the genome mediated by single-guide RNA (sgRNA) at desired genomic loci. The aim of this study is that the animal model of EZH2 gene knockout was constructed using CRISPR/Cas9 technology. METHODS: In this study, we designed two single-guide RNAs targeting the Exon3 and Exon4 of EZH2 gene. Then, their gene-targeting efficiency were detected by SURVEYOR assay. The lentivirus was perfused into the lungs of mice by using a bronchial tube and detected by immunohistochemistry and qRT-PCR. RESULTS: The experimental results of NIH-3T3 cells verify that the designed sgEZH2 can efficiently effect the cleavage of target DNA by Cas9 in vitro. The immunohistochemistry and qRT-PCR results showed that the EZH2 expression in experimental group was significantly decreased in the mouse lung tissue. CONCLUSIONS The study successfully designed two sgRNA which can play a knock-out EZH2 function. An EZH2 knockout animal model was successfully constructed by CRISPR/Cas9 system, and it will be an effective animal model for studying the functions and mechanisms of EZH2.
Animals ; CRISPR-Cas Systems ; Enhancer of Zeste Homolog 2 Protein ; genetics ; metabolism ; Female ; Gene Knockout Techniques ; Gene Targeting ; Humans ; Lung Neoplasms ; genetics ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; RNA, Guide

To investigate the effect of a novel EZH2 inhibitor GSK126 on cell growth, apoptosis and migration of prostate cancer cells.Prostate cancer PC-3 and DU145 cells were treated with GSK126 at different doses. Cell growth was detected by sulforhodamine assay. Cell apoptosis was assayed by Annexin V-/PI kit. Transwell chamber and wound healing assays were conducted to detect cell migration. The mRNA level was detected by quantitative PCR, and protein expression was detected by Western blot analysis.GSK126 showed significant effect on cell growth and apoptosis when the dose was higher than 50 μmol/L. Wound healing assay revealed that scratch space in PC-3 cells was significantly increased in a dose-dependent manner in GSK126-treated groups[(247.2±24.4),(347.2±19.2) and (410.5±18.1) μm in low, medium and high dose (5.0, 20.0, 50.0 μmol/L), respectively] as compared with the control group[(171.3±17.8) μm](all<0.05). Transwell assay showed that migrated PC-3 cells in control group was 322.0±17.9,while those in GSK126-treated groups were 198.3±15.4 (low),82.7±6.2 (medium) and 30.2±4.1 (high), and the differences between the control group and GSK126-treated groups were significant(all<0.05). In addition, GSK126 up-regulated E-cadherin mRNA expression and down-regulated N-cadherin and Vimentin mRNA expression, whereas had no significant effect on Snail, Fibronectin and VEGF-A mRNA expression. The protein expression of E-cadherin was elevated but VEGF-A protein did not change in GSK126-treated groups. Similar results were exhibited in DU145 cell.GSK126 can significantly inhibit cell migration and invasion in prostate cancer PC-3 and DU145 cells, which may be resulted from its effect on epithelial-mesenchymal transition. GSK126 may be used as a potential anti-prostate cancer dug in clinic.
Apoptosis ; drug effects ; Cadherins ; analysis ; drug effects ; metabolism ; Cell Line, Tumor ; drug effects ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Down-Regulation ; drug effects ; Drug Screening Assays, Antitumor ; methods ; Enhancer of Zeste Homolog 2 Protein ; analysis ; drug effects ; metabolism ; Fibronectins ; analysis ; drug effects ; metabolism ; Humans ; Indoles ; pharmacology ; Male ; Prostatic Neoplasms ; chemistry ; genetics ; physiopathology ; Pyridones ; pharmacology ; RNA, Messenger ; Up-Regulation ; drug effects ; Vascular Endothelial Growth Factor A ; analysis ; drug effects ; Vimentin ; analysis ; drug effects ; metabolism