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Ubiquitin-like with PHD and RING finger domains 1 (UHRF1) is an essential protein involved in the maintenance of repressive epigenetic marks, ensuring epigenetic stability and fidelity. As an epigenetic regulator, UHRF1 comprises several functional domains (UBL, TTD, PHD, SRA, RING) that are collectively responsible for processes like DNA methylation, histone modification, and DNA repair. UHRF1 is a downstream effector of the RB/E2F pathway, which is nearly universally deregulated in cancer. Under physiological conditions, UHRF1 protein levels are cell cycle-dependent and are post-translationally regulated by proteasomal degradation. Conversely, UHRF1 is overexpressed and serves as an oncogenic driver in multiple cancers. This review focuses on the functional domains of UHRF1, highlighting its key interacting proteins and oncogenic roles in solid tumors including retinoblastoma, osteosarcoma, lung cancer, and breast cancer. Additionally, current therapeutic strategies targeting UHRF1 domains or its interactors are explored, providing an insight on potential clinical applications.

Background: Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer with limited treatment options and a poor prognosis. The critical role of epigenetic alterations such as changes in DNA methylation, histones modifications, and chromatin remodeling, in pancreatic tumors progression is becoming increasingly recognized. Moreover, in PDAC these aberrant epigenetic mechanisms can also limit therapy efficacy. This study aimed to investigate the expression and prognostic significance of a key epigenetic complex encompassing DNA methyltransferase-1 (DNMT1), the histone methyltransferase G9a, and the scaffold protein UHRF1 in PDAC. We also evaluated the therapeutic potential of an innovative inhibitor targeting these epigenetic effectors. Methods: Immunohistochemical analysis of DNMT1, G9a, and UHRF1 expression was conducted in human PDAC tissue samples. Staining was semi-quantitatively scored, and overexpression was defined as moderate to strong positivity. The prognostic impact was assessed by correlating protein expression with patient survival. The antitumoral effects of the dual DNMT1-G9a inhibitor CM272 were tested in PDAC cell lines, followed by transcriptomic analyses to identify underlying mechanisms. The in vivo antitumoral efficacy of CM272 was evaluated in PDAC xenograft and syngeneic mouse models, both alone and in combination with anti-PD1 immunotherapy. Results: DNMT1, G9a, and UHRF1 were significantly overexpressed in PDAC cells and stroma compared to normal pancreatic tissues. Simultaneous overexpression of the three proteins was associated with significantly reduced survival in resected PDAC patients. CM272 exhibited potent antiproliferative activity in PDAC cell lines, inducing apoptosis and altering key metabolic and cell cycle-related genes. CM272 also enhanced chemotherapy sensitivity and significantly inhibited tumor growth in vivo without detectable toxicity. Combination of CM272 with anti-PD1 therapy further improved antitumor responses and immune cell infiltration, particularly CD4 + and CD8 + T cells. Conclusions: The combined overexpression of DNMT1, G9a, and UHRF1 in PDAC is a strong predictor of poor prognosis. CM272, by targeting this epigenetic complex, shows promising therapeutic potential by inducing apoptosis, reprogramming metabolic pathways, and enhancing immune responses. The combination of CM272 with immunotherapy offers a novel, effective treatment strategy for PDAC. [ABSTRACT FROM AUTHOR]

Background: Aberrant interplay between epigenetic reprogramming and metabolic rewiring events contributes to bladder cancer progression and metastasis. How the deacetylase Sirtuin-6 (SIRT6) regulates glycolysis and lactate secretion in bladder cancer remains poorly defined. We thus aimed to study the biological functions of SIRT6 in bladder cancer. Methods: Bioinformatic analysis was used to study the prognostic significance of SIRT6/UHRF1 in BLCA. Both in vitro and in vivo assays were used to determine the roles of SIRT6/UHRF1 in BLCA. Deacetylation and ubiquitin assays were performed to uncover the regulations of SIRT6-UHRF1. Measurement of extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) was used to assess glycolytic abilities. Results: Here, we show that protein deacetylase SIRT6 was down-regulated in BLCA, and predicts poor overall survival. SIRT6 deficiency notably enhances BLCA cell proliferation, self-renewal, and migration capacities in vitro and in vivo. Mechanistically, SIRT6 interacts with, deacetylates, and promotes UHRF1 degradation mediated by β-TrCP1. Thus, SIRT6 deficiency leads to stabilized UHRF1 and depends on UHRF1 to accelerate BLCA malignant progression. Furthermore, UHRF1 significantly increased aerobic glycolysis via activating MCT4/HK2 expressions. Down-regulated SIRT6 thus depended on UHRF1 to promote glycolysis and lactate secretion in BLCA. Targeting UHRF1 or MCT4 notably impaired the extracellular lactate accumulations in BLCA. Significantly, a specific small-molecule inhibitor (NSC232003) targeting UHRF1 substantially inhibited SIRT6-deficient BLCA progression. Conclusion: Together, our study uncovered an epigenetic mechanism of the SIRT6/UHRF1 axis in driving BLCA glycolysis and lactate secretion, creating a novel vulnerability for BLCA treatment. [ABSTRACT FROM AUTHOR]

RAD51 is related to the bacterial RecA protein and is best known for its role in homologous recombination-mediated repair of DNA damage. Here, we report an unexpected function of RAD51 in the maintenance methylation of genomic DNA, a function that is separable from its role in homologous recombination. First, it acts as an inhibitor of the E3 ubiquitin ligase UHRF1. Deficiency in RAD51 causes excessive ubiquitination and degradation of the DNA methyltransferase DNMT1, leading to the loss of global DNA methylation. Second, RAD51 helps UHRF1 to monoubiquitinate histone H3 to generate DNMT1 recruiting signal. It binds H3 directly, enabling UHRF1 to bind and ubiquitinate H3 more readily. Disrupting the interaction between RAD51 and H3 diminishes DNMT1 recruitment and the failure of maintenance methylation of genomic DNA. Thus, RAD51 dually regulates UHRF1. These results establish RAD51 as a guardian of the integrity of both the genome and the epigenome. [ABSTRACT FROM AUTHOR]

Ubiquitin-like containing PHD and RING finger domains 1 (UHRF1) is involved in tumorigenicity through DNA methylation in various cancers, including breast cancer. This study aims to investigate the regulatory mechanisms of UHRF1 in breast cancer progression. Herein, we show that UHRF1 is upregulated in breast cancer tissues and cell lines as measured by western blot analysis and immunohistochemistry. Breast cancer cells are transfected with a UHRF1 overexpression plasmid (pcDNA-UHRF1) or short hairpin RNA targeting UHRF1 (sh-UHRF1), followed by detection of cell proliferation, invasion, apoptosis, and cell cycle. UHRF1 overexpression promotes proliferation and invasion and attenuates cell cycle arrest and apoptosis in breast cancer cells, while UHRF1 knockdown shows the opposite effect. Moreover, methylation‐specific PCR and ChIP assays indicate that UHRF1 inhibits zinc finger and BTB domain containing 16 (ZBTB16) expression by promoting ZBTB16 promoter methylation via the recruitment of DNA methyltransferase 1 (DNMT1). Then, a co-IP assay is used to verify the interaction between ZBTB16 and the annexin A7 (ANXA7) protein. ZBTB16 promotes ANXA7 expression and subsequently inhibits Cyclin B1 expression. Rescue experiments reveal that ZBTB16 knockdown reverses the inhibitory effects of UHRF1 knockdown on breast cancer cell malignancies and that ANXA7 knockdown abolishes the inhibitory effects of ZBTB16 overexpression on breast cancer cell malignancies. Additionally, UHRF1 knockdown significantly inhibits xenograft tumor growth in vivo. In conclusion, UHRF1 knockdown inhibits proliferation and invasion, induces cell cycle arrest and apoptosis in breast cancer cells via the ZBTB16/ANXA7/Cyclin B1 axis, and reduces xenograft tumor growth in vivo.

Abstract Background Cholangiocarcinoma (CCA) is a highly malignant tumor characterized by a lack of effective targeted therapeutic strategies. The protein UHRF1 plays a pivotal role in the preservation of DNA methylation and works synergistically with DNMT1. Posttranscriptional modifications (PTMs), such as ubiquitination, play indispensable roles in facilitating this process. Nevertheless, the specific PTMs that regulate UHRF1 in CCA remain unidentified. Methods We confirmed the interaction between STUB1 and UHRF1 through mass spectrometry analysis. Furthermore, we investigated the underlying mechanisms of the STUB1-UHRF1/DNMT1 axis via co-IP experiments, denaturing IP ubiquitination experiments, nuclear‒cytoplasmic separation and immunofluorescence experiments. The downstream PLA2G2A gene, regulated by the STUB1-UHRF1/DNMT1 axis, was identified via RNA-seq. The negative regulatory mechanism of PLA2G2A was explored via bisulfite sequencing PCR (BSP) experiments to assess changes in promoter methylation. The roles of PLA2G2A and STUB1 in the proliferation, invasion, and migration of CCA cells were assessed using the CCK-8 assay, colony formation assay, Transwell assay, wound healing assay and xenograft mouse model. We evaluated the effects of STUB1/UHRF1 on cholangiocarcinoma by utilizing a primary CCA mouse model. Results This study revealed that STUB1 interacts with UHRF1, resulting in an increase in the K63-linked ubiquitination of UHRF1. Consequently, this facilitates the nuclear translocation of UHRF1 and enhances its binding affinity with DNMT1. The STUB1-UHRF1/DNMT1 axis led to increased DNA methylation of the PLA2G2A promoter, subsequently repressing its expression. Increased STUB1 expression in CCA was inversely correlated with tumor progression and overall survival. Conversely, PLA2G2A functions as a tumor suppressor in CCA by inhibiting cell proliferation, invasion and migration. Conclusions These findings suggest that the STUB1-mediated ubiquitination of UHRF1 plays a pivotal role in tumor progression by epigenetically silencing PLA2G2A, underscoring the potential of STUB1 as both a prognostic biomarker and therapeutic target for CCA. Graphical Abstract

The cytoplasmic lattices (CPLs) are fibrous structures of the mammalian oocyte cytoplasm that are needed to store ribosomes and maternal proteins in insoluble form to prevent their degradation, activation, and nuclear transfer. UHRF1 and the members of the subcortical maternal complex colocalize with the CPLs, and their deficiency results in lattice impairment. Mutations in the maternal effect genes Nlrp14 and Padi6 cause maturation defects and CPL deficiency in mouse oocytes, leading to lack of the CPL storage function and impaired cytoplasmic UHRF1 abundance, abnormal nuclear localization of DNMT1, and failure of epigenetic reprogramming, as well as defective zygotic genome activation and embryo development beyond the two-cell stage. Mouse mutants of CPL-associated proteins do not mimic human imprinting defects, suggesting species-specific differences. Oocyte maturation and preimplantation embryo development are critical to successful pregnancy outcomes and the correct establishment and maintenance of genomic imprinting. Thanks to novel technologies and omics studies in human patients and mouse models, the importance of the proteins associated with the cytoplasmic lattices (CPLs), highly abundant structures found in the cytoplasm of mammalian oocytes and preimplantation embryos, in the maternal to zygotic transition is becoming increasingly evident. This review highlights the recent discoveries on the role of these proteins in protein storage and other oocyte cytoplasmic processes, epigenetic reprogramming, and zygotic genome activation (ZGA). A better comprehension of these events may significantly improve clinical diagnosis and pave the way for targeted interventions aiming to correct or mitigate female fertility issues and genomic imprinting disorders. [ABSTRACT FROM AUTHOR]

Background: Cholangiocarcinoma (CCA) is a highly malignant tumor characterized by a lack of effective targeted therapeutic strategies. The protein UHRF1 plays a pivotal role in the preservation of DNA methylation and works synergistically with DNMT1. Posttranscriptional modifications (PTMs), such as ubiquitination, play indispensable roles in facilitating this process. Nevertheless, the specific PTMs that regulate UHRF1 in CCA remain unidentified. Methods: We confirmed the interaction between STUB1 and UHRF1 through mass spectrometry analysis. Furthermore, we investigated the underlying mechanisms of the STUB1-UHRF1/DNMT1 axis via co-IP experiments, denaturing IP ubiquitination experiments, nuclear‒cytoplasmic separation and immunofluorescence experiments. The downstream PLA2G2A gene, regulated by the STUB1-UHRF1/DNMT1 axis, was identified via RNA-seq. The negative regulatory mechanism of PLA2G2A was explored via bisulfite sequencing PCR (BSP) experiments to assess changes in promoter methylation. The roles of PLA2G2A and STUB1 in the proliferation, invasion, and migration of CCA cells were assessed using the CCK-8 assay, colony formation assay, Transwell assay, wound healing assay and xenograft mouse model. We evaluated the effects of STUB1/UHRF1 on cholangiocarcinoma by utilizing a primary CCA mouse model. Results: This study revealed that STUB1 interacts with UHRF1, resulting in an increase in the K63-linked ubiquitination of UHRF1. Consequently, this facilitates the nuclear translocation of UHRF1 and enhances its binding affinity with DNMT1. The STUB1-UHRF1/DNMT1 axis led to increased DNA methylation of the PLA2G2A promoter, subsequently repressing its expression. Increased STUB1 expression in CCA was inversely correlated with tumor progression and overall survival. Conversely, PLA2G2A functions as a tumor suppressor in CCA by inhibiting cell proliferation, invasion and migration. Conclusions: These findings suggest that the STUB1-mediated ubiquitination of UHRF1 plays a pivotal role in tumor progression by epigenetically silencing PLA2G2A, underscoring the potential of STUB1 as both a prognostic biomarker and therapeutic target for CCA. [ABSTRACT FROM AUTHOR]

ABSTRACTEmerging evidence has revealed the novel role of gut microbiota in the development of cancer. The characteristics of function and composition in the gut microbiota of patients with breast cancer patients has been reported, however the detailed causation between gut microbiota and breast cancer remains uncertain. In the present study, 16S rRNA sequencing revealed that Prevotella, particularly the dominant species Prevotella copri, is significantly enriched and prevalent in gut microbiota of breast cancer patients. Prior-oral administration of P. copri could promote breast cancer growth in specific pathogen-free mice and germ-free mice, accompanied with sharp reduction of indole-3-pyruvic acid (IPyA). Mechanistically, the present of excessive P. copri consumed a large amount of tryptophan (Trp), thus hampering the physiological accumulation of IPyA in the host. Our results revealed that IPyA is an intrinsic anti-cancer reagent in the host at physiological level. Briefly, IPyA directly suppressed the transcription of UHRF1, following by the declined UHRF1 and PP2A C in nucleus, thus inhibiting the phosphorylation of AMPK, which is just opposite to the cancer promoting effect of P. copri. Therefore, the exhaustion of IPyA by excessive P. copri strengthens the UHRF1-mediated negative control to inactivated the energy-controlling AMPK signaling pathway to promote tumor growth, which was indicated by the alternation in pattern of protein expression and DNA methylation. Our findings, for the first time, highlighted P. copri as a risk factor for the progression of breast cancer.

Abstract UHRF1 as a member of RING-finger type E3 ubiquitin ligases family, is an epigenetic regulator with five structural domains. It has been involved in the regulation of a series of biological functions, such as DNA replication, DNA methylation, and DNA damage repair. Additionally, aberrant overexpression of UHRF1 has been observed in over ten cancer types, indicating that UHRF1 is a typical oncogene. The overexpression of UHRF1 repressed the transcription of such tumor-suppressor genes as CDKN2A, BRCA1, and CDH1 through DNMT1-mediated DNA methylation. In addition to the upstream transcription factors regulating gene transcription, post-translational modifications (PTMs) also contribute to abnormal overexpression of UHRF1 in cancerous tissues. The types of PTM include phosphorylation, acetylation, methylationand ubiquitination, which regulate protein stability, histone methyltransferase activity, intracellular localization and the interaction with binding partners. Recently, several novel PTM types of UHRF1 have been reported, but the detailed mechanisms remain unclear. This comprehensive review summarized the types of UHRF1 PTMs, as well as their biological functions. A deep understanding of these crucial mechanisms of UHRF1 is pivotal for the development of novel UHRF1-targeted anti-cancer therapeutic strategies in the future.

Synovial sarcoma (SS) is an aggressive soft tissue sarcoma with poor prognosis due to late recurrence and metastasis. Metastasis is an important prognostic factor of SS. This study aimed to identify the core genes and mechanisms associated with SS metastasis. Microarray data for GSE40021 and GSE40018 were obtained from the Gene Expression Omnibus database. 186 differentially expressed genes (DEGs) were identified. The biological functions and signalling pathways closely associated with SS metastasis included extracellular matrix (ECM) organization and ECM‐receptor interaction. Gene set enrichment analysis showed that the terms cell cycle, DNA replication, homologous recombination and mismatch repair were significantly enriched in the metastasis group. Weighted gene co‐expression network analysis identified the most relevant module and 133 hub genes, and 31 crossover genes were identified by combining DEGs. Subsequently, four characteristic genes, EXO1, NCAPG, POLQ and UHRF1, were identified as potential biomarkers associated with SS metastasis using the least absolute shrinkage and selection operator algorithm and validation dataset verification analysis. Immunohistochemistry results from our cohort of 49 patients revealed visible differences in the expression of characteristic genes between the non‐metastatic and metastatic groups. Survival analysis indicated that high expression of characteristic genes predicted poor prognosis. Our data revealed that primary SS samples from patients who developed metastasis showed activated homologous recombination and mismatch repair compared to samples from patients without metastasis. Furthermore, EXO1, NCAPG, POLQ and UHRF1 were identified as potential candidate metastasis‐associated genes. This study provides further research insights and helps explore the mechanisms of SS metastasis. [ABSTRACT FROM AUTHOR]

Backgrounds: Diabetic nephropathy (DN) is the leading cause of end-stage renal disease, and current treatment options to prevent its progression are inadequate. Podocyte injury is crucial to the pathogenesis of DN. Objective: This study aimed to investigate the effect of UHRF1 on high glucose (HG)-induced podocyte injury and to explore its molecular mechanism. Results: HG induced MPC5 cells to highly express UHRF1 while downregulating SIRT4. Knockdown of UHRF1 promoted HG-induced proliferation of MPC5 cells and ameliorated HG-induced cell cycle arrest, apoptosis, and ROS levels. Knockdown of UHRF1 ameliorated HG-induced podocyte injury by upregulating SIRT4. Conclusions: Knockdown of UHRF1 ameliorates HG-induced podocyte injury by upregulating SIRT4, indicating that UHRF1 may be a novel target for preventing DN in podocytes. [ABSTRACT FROM AUTHOR]

Endothelial cell injury and dysfunction lead to cholesterol and lipid accumulation and atherosclerotic plaque formation in the arterial wall during atherosclerosis (AS) progression, Ubiquitin-like containing PHD and RING finger domain 1 (UHRF1), a DNA methylation regulator, was strongly upregulated in atherosclerotic plaque lesions in mice. This study aimed to investigate the precise biological functions and regulatory mechanisms of UHRF1 on endothelial dysfunction during AS development. UHRF1 levels in the atherosclerotic plaque tissues and normal arterial intima from AS patients were tested with Western blot analysis and immunohistochemistry assays. Human umbilical vein endothelial cells (HUVECs) were stimulated with oxidized low-density lipoprotein (ox-LDL) to induce an injury model and then transfected with short hairpin RNA targeting UHRF1 (sh-UHRF1). Cell proliferation, migration, apoptosis, the levels of inflammatory cytokines including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and the protein levels adhesion molecules including vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were measured. Moreover, co-immunoprecipitation assay was used to determine the interactions between UHRF1 and DNA methyltransferases 1 (DNMT1), As well as mothers against DPP homolog 7 (SMAD7) and yes-associated protein 1 (YAP1). SMAD7 promoter methylation was examined with methylation-specific PCR. In addition, we established an AS mouse model to determine the in vivo effects of UHRF1 on AS progression. UHRF1 was upregulated in atherosclerotic plaque tissues and ox-LDL-treated HUVECs. UHRF1 knockdown mitigated ox-LDL-induced proliferation and migration inhibition, apoptosis and the production of TNF-α, IL-6, VCAM-1, and ICAM-1 in HUVECs. Mechanistically, UHRF1 promoted DNMT1-mediated SMAD7 promoter methylation and inhibited its expression. SMAD7 knockdown abolished the protective effects of UHRF1 knockdown on ox-LDL-induced HUVEC injury. Moreover, SMAD7 interacted with YAP1 and inhibited YAP1 expression by promoting YAP1 protein ubiquitination-independent degradation in HUVECs. YAP1 overexpression abrogated SMAD7 overexpression-mediated protective effects on ox-LDL-induced HUVEC injury. Finally, UHRF1 knockdown alleviated atherosclerotic plaque deposition and arterial lesions in AS mice. UHRF1 inhibition mitigates vascular endothelial cell injury and ameliorates AS progression in mice by regulating the SMAD7/YAP1 axis [Display omitted] • UHRF1 knockdown facilitated cell proliferation and mitigated apoptosis and inflammation in ox-LDL-treated HUVECs. • UHRF1 inhibited SMAD7 expression by promoting DNMT1-mediated SMAD7 promoter methylation. • SMAD7 knockdown abrogated the protective effects of UHRF1 knockdown on ox-LDL-induced HUVEC injury. • YAP1 overexpression abrogated the protective effects of SMAD7 overexpression on ox-LDL-induced HUVEC injury. • UHRF1 knockdown ameliorated atherosclerotic plaque deposition and arterial lesions in AS mice. [ABSTRACT FROM AUTHOR]

Context: Ubiquitin-like with PHD and RING finger domain containing protein 1 (UHRF1) is responsible for preserving the stability of genomic methylation through the recruitment of DNA methyltransferase 1 (DNMT1). However, the interaction between Developmental pluripotency associated 3 (DPPA3) and the pre-PHD-PHD (PPHD) domain of UHRF1 hinders the nuclear localization of UHRF1. This disruption has implications for potential cancer treatment strategies. Drugs that mimic the binding pattern between DPPA3 and PPHD could offer a promising approach to cancer treatment. Our study reveals that DPPA3 undergoes dissociation from the C-terminal through three different modes of helix unfolding. Furthermore, we have identified key residue pairs involved in this dissociation process and potential drug-targeting residues. These findings offer valuable insights into the dissociation mechanism of DPPA3 from PPHD and have the potential to inform the design of novel drugs targeting UHRF1 for cancer therapy. Methods: To comprehend the dissociation process and binding patterns of PPHD-DPPA3, we employed enhanced sampling techniques, including steered molecular dynamics (SMD) and conventional molecular dynamics (cMD). Additionally, we utilized self-organizing maps (SOM) and time-resolved force distribution analysis (TRFDA) methodologies. The Gromacs software was used for performing molecular dynamics simulations, and the AMBER FF14SB force field was applied to the protein. [ABSTRACT FROM AUTHOR]

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UHRF1 as a member of RING-finger type E3 ubiquitin ligases family, is an epigenetic regulator with five structural domains. It has been involved in the regulation of a series of biological functions, such as DNA replication, DNA methylation, and DNA damage repair. Additionally, aberrant overexpression of UHRF1 has been observed in over ten cancer types, indicating that UHRF1 is a typical oncogene. The overexpression of UHRF1 repressed the transcription of such tumor-suppressor genes as CDKN2A, BRCA1, and CDH1 through DNMT1-mediated DNA methylation. In addition to the upstream transcription factors regulating gene transcription, post-translational modifications (PTMs) also contribute to abnormal overexpression of UHRF1 in cancerous tissues. The types of PTM include phosphorylation, acetylation, methylationand ubiquitination, which regulate protein stability, histone methyltransferase activity, intracellular localization and the interaction with binding partners. Recently, several novel PTM types of UHRF1 have been reported, but the detailed mechanisms remain unclear. This comprehensive review summarized the types of UHRF1 PTMs, as well as their biological functions. A deep understanding of these crucial mechanisms of UHRF1 is pivotal for the development of novel UHRF1-targeted anti-cancer therapeutic strategies in the future. [ABSTRACT FROM AUTHOR]

background: Accurate diagnosis, early detection, and differentiation of lung adenocarcinoma from mesothelioma; particularly the epithelioid subtype is needed to allow better management thus to improve their prognosis.Aim of our study was to assess applicability of CPA4, UHRF1, glypican-1 and CD90 expression by immunohistochemistry to differentiate between lung adenocarcinoma and epithelioid mesothelioma in addition to detection of their prognostic roles and relation to patients' survival. Methods: We collected samples from 30 patients diagnosed with lung adenocarcinoma and 30 patients diagnosed with epithelioid mesothelioma. For the immunohistochemistry, sections of all collected samples were incubated with CPA4, UHRF1, glypican-1 and CD90 to assess their diagnostic accuracy. RESULTS: A highly significant association was detected between positive CPA4, UHRF1 expression in lung adenocarcinoma and their diagnostic accuracy (p value <0.001). Also, highly significant association was detected between positive CD90, Glypican 1 expression in epithelioid mesothelioma and their diagnostic accuracy (p value <0.001). CPA4 expression was associated with shorter OS rate (P value 0.019, 0.009) UHRF1 expression was associated with shorter OS rate (P value=0.009) Conclusions: CPA4, UHRF1, glypican-1 and CD90 were considered novel biomarkers that have important roles in differentiation between epithelioid malignant mesothelioma and adenocarcinoma of the lung with high sensitivity and specificity. [ABSTRACT FROM AUTHOR]

Gallbladder cancer is a rare but fatal malignancy. However, the mechanisms underlying gallbladder carcinogenesis and its progression are poorly understood. The function of m6A modification and its regulators was still unclear for gallbladder cancer. The current study seeks to investigate the function of YTH m6A RNA‐binding protein 1 (YTHDF1) in gallbladder cancer. Transcriptomic analysis and immunochemical staining of YTHDF1 in gallbladder cancer tissues revealed its upregulation compared to paracancerous tissues. Moreover, YTHDF1 promotes the proliferation assays, Transwell migration assays, and Transwell invasion assays of gallbladder cancer cells in vitro. And it also increased tumour growth in xenograft mouse model and metastases in tail vein injection model in vivo. In vitro, UHRF1 knockdown partly reversed the effects of YTHDF1 overexpression. Mechanistically, dual‐luciferase assays proved that YTHDF1 promotes UHRF1 expression via direct binding to the mRNA 3′‐UTR in a m6A‐dependent manner. Overexpression of YTHDF1 enhanced UHRF1 mRNA stability, as demonstrated by mRNA stability assays, and Co‐IP studies confirmed a direct interaction between YTHDF1 and PABPC1. Collectively, these findings provide new insights into the progression of gallbladder cancer as well as a novel post‐transcriptional mechanism of YTHDF1 via stabilizing target mRNA. [ABSTRACT FROM AUTHOR]

Abstract Background Repeat elements (REs) play important roles for cell function in health and disease. However, RE enrichment analysis in short-read high-throughput sequencing (HTS) data, such as ChIP-seq, is a challenging task. Results Here, we present RepEnTools, a software package for genome-wide RE enrichment analysis of ChIP-seq and similar chromatin pulldown experiments. Our analysis package bundles together various software with carefully chosen and validated settings to provide a complete solution for RE analysis, starting from raw input files to tabular and graphical outputs. RepEnTools implementations are easily accessible even with minimal IT skills (Galaxy/UNIX). To demonstrate the performance of RepEnTools, we analysed chromatin pulldown data by the human UHRF1 TTD protein domain and discovered enrichment of TTD binding on young primate and hominid specific polymorphic repeats (SVA, L1PA1/L1HS) overlapping known enhancers and decorated with H3K4me1-K9me2/3 modifications. We corroborated these new bioinformatic findings with experimental data by qPCR assays using newly developed primate and hominid specific qPCR assays which complement similar research tools. Finally, we analysed mouse UHRF1 ChIP-seq data with RepEnTools and showed that the endogenous mUHRF1 protein colocalizes with H3K4me1-H3K9me3 on promoters of REs which were silenced by UHRF1. These new data suggest a functional role for UHRF1 in silencing of REs that is mediated by TTD binding to the H3K4me1-K9me3 double mark and conserved in two mammalian species. Conclusions RepEnTools improves the previously available programmes for RE enrichment analysis in chromatin pulldown studies by leveraging new tools, enhancing accessibility and adding some key functions. RepEnTools can analyse RE enrichment rapidly, efficiently, and accurately, providing the community with an up-to-date, reliable and accessible tool for this important type of analysis.

Background: Repeat elements (REs) play important roles for cell function in health and disease. However, RE enrichment analysis in short-read high-throughput sequencing (HTS) data, such as ChIP-seq, is a challenging task. Results: Here, we present RepEnTools, a software package for genome-wide RE enrichment analysis of ChIP-seq and similar chromatin pulldown experiments. Our analysis package bundles together various software with carefully chosen and validated settings to provide a complete solution for RE analysis, starting from raw input files to tabular and graphical outputs. RepEnTools implementations are easily accessible even with minimal IT skills (Galaxy/UNIX). To demonstrate the performance of RepEnTools, we analysed chromatin pulldown data by the human UHRF1 TTD protein domain and discovered enrichment of TTD binding on young primate and hominid specific polymorphic repeats (SVA, L1PA1/L1HS) overlapping known enhancers and decorated with H3K4me1-K9me2/3 modifications. We corroborated these new bioinformatic findings with experimental data by qPCR assays using newly developed primate and hominid specific qPCR assays which complement similar research tools. Finally, we analysed mouse UHRF1 ChIP-seq data with RepEnTools and showed that the endogenous mUHRF1 protein colocalizes with H3K4me1-H3K9me3 on promoters of REs which were silenced by UHRF1. These new data suggest a functional role for UHRF1 in silencing of REs that is mediated by TTD binding to the H3K4me1-K9me3 double mark and conserved in two mammalian species. Conclusions: RepEnTools improves the previously available programmes for RE enrichment analysis in chromatin pulldown studies by leveraging new tools, enhancing accessibility and adding some key functions. RepEnTools can analyse RE enrichment rapidly, efficiently, and accurately, providing the community with an up-to-date, reliable and accessible tool for this important type of analysis. [ABSTRACT FROM AUTHOR]

Diabetic nephropathy (DN) is a common diabetic complication. Studies show that mitophagy inhibition induced-ferroptosis plays a crucial role in DN progression. UHRF1 is associated with mitophagy and is highly expression in DN patients, however, the effect of UHRF1 on DN is still unclear. Thus, in this study, we aimed to investigate whether UHRF1 involves DN development by the mitophagy/ferroptosis pathway. We overexpressed UHRF1 using an adeno-associated virus 9 (AAV9) system in high-fat diet/streptozotocin-induced diabetic mice. Renal function index, pathological changes, mitophagy factors, and ferroptosis factors were detected in vivo. High-glucose cultured human renal proximal tubular (HK-2) cells were used as in vitro models to investigate the mechanism of UHRF1 in DN. We found that diabetic mice exhibited kidney damage, which was alleviated by UHRF1 overexpression. UHRF1 overexpression promoted PINK1-mediated mitophagy and inhibited the expression of thioredoxin interacting protein (TXNIP), a factor associated with mitochondrial dysfunction. Additionally, UHRF1 overexpression alleviated lipid peroxidation and free iron accumulation, and upregulated the expression of GPX4 and Slc7a11, indicating the inhibition effect of UHRF1 overexpression on ferroptosis. We further investigated the mechanism of UHRF1 in the mitophagy/ferroptosis pathway in DN. We found that UHRF1 overexpression promoted PINK1-mediated mitophagy via inhibiting TXNIP expression, thus suppressing ferroptosis. These findings confirmed that upregulation of UHRF1 expression alleviates DN, indicating that UHRF1 has a reno-protective effect against DN. [ABSTRACT FROM AUTHOR]

Pluripotency is established in E4.5 preimplantation epiblast. Embryonic stem cells (ESCs) represent the immortalization of pluripotency, however, their gene expression signature only partially resembles that of developmental ground-state. Induced PRAMEL7 expression, a protein highly expressed in the ICM but lowly expressed in ESCs, reprograms developmentally advanced ESC+serum into ground-state pluripotency by inducing a gene expression signature close to developmental ground-state. However, how PRAMEL7 reprograms gene expression remains elusive. Here we show that PRAMEL7 associates with Cullin2 (CUL2) and this interaction is required to establish ground-state gene expression. PRAMEL7 recruits CUL2 to chromatin and targets regulators of repressive chromatin, including the NuRD complex, for proteasomal degradation. PRAMEL7 antagonizes NuRD-mediated repression of genes implicated in pluripotency by decreasing NuRD stability and promoter association in a CUL2-dependent manner. Our data link proteasome degradation pathways to ground-state gene expression, offering insights to generate in vitro models to reproduce the in vivo ground-state pluripotency. Synopsis: PRAMEL7 reprograms ESC to ground-state pluripotency by recruiting CUL2 to chromatin and targeting chromatin regulators for proteasomal degradation. This leads to a gene expression signature close to developmental ground-state, linking proteasome degradation pathways to ground-state gene expression. PRAMEL7 associates with and recruits CULLIN2 to chromatin. PRAMEL7-CULLIN2 interaction is required to establish gene expression signature close to developmental ground-state. PRAMEL7 targets regulators of repressive chromatin, including the NuRD complex, for proteasomal degradation in a CULLIN2-dependent manner. PRAMEL7 antagonizes NuRD-mediated repression by decreasing NuRD stability and promoter association in a CUL2-dependent manner. PRAMEL7 reprograms ESC to ground-state pluripotency by recruiting CUL2 to chromatin and targeting chromatin regulators for proteasomal degradation. This leads to a gene expression signature close to developmental ground-state, linking proteasome degradation pathways to ground-state gene expression. [ABSTRACT FROM AUTHOR]

Background and Aim: Circular ubiquitin‐like, containing PHD and ring finger domains 1 (circUHRF1) is aberrantly upregulated in human hepatocellular carcinoma (HCC) tissues. However, the underlying molecular mechanisms remain obscure. The present study aimed at elucidating the interactive function of circUHRF1–G9a–ubiquitin‐like, containing PHD and ring finger domains 1 (UHRF1) mRNA–eukaryotic translation initiation factor 4A3 (EIF4A3)–PDZ and LIM domain 1 (PDLIM1) network in HCC. Methods: Expression of circUHRF1, mRNAs of G9a, UHRF1, PDLIM1, epithelial–mesenchymal transition (EMT)‐related proteins, and Hippo–Yap pathway components was determined by quantitative polymerase chain reaction (Q‐PCR), immunofluorescence, or Western blot analysis. Tumorigenic and metastatic capacities of HCC cells were examined by cellular assays including Cell Counting Kit‐8, colony formation, wound healing, and transwell assays. Molecular interactions between EIF4A3 and UHRF1 mRNA were detected by RNA pull‐down experiment. Complex formation between UHRF1 and PDLIM1 promoter was detected by chromatin immunoprecipitation assay. Co‐immunoprecipitation was performed to examine the binding between UHRF1 and G9a. Results: Circular ubiquitin‐like, containing PHD and ring finger domains 1, G9a, and UHRF1 were upregulated, while PDLIM1 was downregulated in HCC tissue samples and cell lines. Cellular silencing of circUHRF1 repressed HCC proliferation, invasion, migration, and EMT. G9a formed a complex with UHRF1 and inhibited PDLIM1 transcription. Conclusion: Eukaryotic translation initiation factor 4A3 regulated circUHRF1 expression by binding to UHRF1 mRNA promoter. circUHRF1 increased the stability of G9a and UHRF1 mRNAs through recruiting EIF4A3. Overexpression of circUHRF1 aggravated HCC progression through Hippo–Yap pathway and PDLIM1 inhibition. By elucidating the molecular function of circUHRF1–G9a–UHRF1 mRNA–EIF4A3–PDLIM1 network, our data shed light on the HCC pathogenesis and suggest a novel therapeutic strategy for future HCC treatment. [ABSTRACT FROM AUTHOR]

The oocyte is considered to be the largest cell in mammalian species. Women hoping to become pregnant face a ticking biological clock. This is becoming increasingly challenging as an increase in life expectancy is accompanied by the tendency to conceive at older ages. With advancing maternal age, the fertilized egg will exhibit lower quality and developmental competence, which contributes to increased chances of miscarriage due to several causes such as aneuploidy, oxidative stress, epigenetics, or metabolic disorders. In particular, heterochromatin in oocytes and with it, the DNA methylation landscape undergoes changes. Further, obesity is a well-known and ever-increasing global problem as it is associated with several metabolic disorders. More importantly, both obesity and aging negatively affect female reproduction. However, among women, there is immense variability in age-related decline of oocytes' quantity, developmental competence, or quality. Herein, the relevance of obesity and DNA-methylation will be discussed as these aspects have a tremendous effect on female fertility, and it is a topic of continuous and widespread interest that has yet to be fully addressed for the mammalian oocyte. [ABSTRACT FROM AUTHOR]

BackgroundThe multiplicity, heterogeneity, and dynamic nature of human immunodeficiency virus type-1 (HIV-1) latency mechanisms are reflected in the current lack of functional cure for HIV-1. Accordingly, all classes of latency-reversing agents (LRAs) have been reported to present variable ex vivo potencies. Here, we investigated the molecular mechanisms underlying the potency variability of one LRA: the DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-AzadC).MethodsWe employed epigenetic interrogation methods (electrophoretic mobility shift assays, chromatin immunoprecipitation, Infinium array) in complementary HIV-1 infection models (latently-infected T-cell line models, primary CD4+ T-cell models and ex vivo cultures of PBMCs from HIV+ individuals). Extracellular staining of cell surface receptors and intracellular metabolic activity were measured in drug-treated cells. HIV-1 expression in reactivation studies was explored by combining the measures of capsid p24Gag protein, green fluorescence protein signal, intracellular and extracellular viral RNA and viral DNA.FindingsWe uncovered specific demethylation CpG signatures induced by 5-AzadC in the HIV-1 promoter. By analyzing the binding modalities to these CpG, we revealed the recruitment of the epigenetic integrator Ubiquitin-like with PHD and RING finger domain 1 (UHRF1) to the HIV-1 promoter. We showed that UHRF1 redundantly binds to the HIV-1 promoter with different binding modalities where DNA methylation was either non-essential, essential or enhancing UHRF1 binding. We further demonstrated the role of UHRF1 in the epigenetic repression of the latent viral promoter by a concerted control of DNA and histone methylations.InterpretationA better understanding of the molecular mechanisms of HIV-1 latency allows for the development of innovative antiviral strategies. As a proof-of-concept, we showed that pharmacological inhibition of UHRF1 in ex vivo HIV+ patient cell cultures resulted in potent viral reactivation from latency. Together, we identify UHRF1 as a novel actor in HIV-1 epigenetic silencing and highlight that it constitutes a new molecular target for HIV-1 cure strategies.FundingFunding was provided by the Belgian National Fund for Scientific Research (F.R.S.-FNRS, Belgium), the « Fondation Roi Baudouin », the NEAT (European AIDS Treatment Network) program, the Internationale Brachet Stiftung, ViiV Healthcare, the Télévie, the Walloon Region (« Fonds de Maturation »), « Les Amis des Instituts Pasteur à Bruxelles, asbl », the University of Brussels (Action de Recherche Concertée ULB grant), the Marie Skodowska Curie COFUND action, the European Union's Horizon 2020 research and innovation program under grant agreement No 691119-EU4HIVCURE-H2020-MSCA-RISE-2015, the French Agency for Research on AIDS and Viral Hepatitis (ANRS), the Sidaction and the "Alsace contre le Cancer" Foundation. This work is supported by 1UM1AI164562-01, co-funded by National Heart, Lung and Blood Institute, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Neurological Disorders and Stroke, National Institute on Drug Abuse and the National Institute of Allergy and Infectious Diseases.

Objective To explore the relationship of UHRF1 with the clinicopathological characteristics of colorectal cancer (CRC) patients, as well as the effects of lentivirus transfection overexpression and knockdown of UHRF1 on the proliferation, invasion, and migration of CRC cells and the possible signaling pathways. Methods The expression of UHRF1 mRNA and protein in CRC tissues and adjacent tissues was detected by immunohistochemical staining and RT-PCR. The effects of the constructed UHRF1 overexpression- and knockdown-group cells on the expression of UHRF1, related molecules in the WNT signaling pathway, and MMPR9 were examined by Western blot and RT-PCR. EDU and Transwell assays were used to detect changes in the proliferation, migration, and invasion of CRC cells. Results (1) In the TCGA database and clinical data, the mRNA and protein expression levels of UHRF1 in CRC cancer tissues were significantly higher than those in adjacent normal tissues. UHRF1 expression was closely correlated with TNM stage, N stage, and M stage. Patients with low UHRF1 expression in TCGA had better 5-year OS and disease-specific survival. The area under the ROC curve of UHRF1 for predicting 1-, 3-, and 5-year OS were 0.634, 0.652, and 0.771, respectively. The 3-year OS in the clinical data also showed the same survival benefit. UHRF1 overexpression was a poor prognostic factor for CRC patients. (2) After UHRF1 overexpression, the expression of WNT3a, GSK3β, and MMP9 in SW480 cells significantly increased, whereas the expression of p-β-catenin decreased (P < 0.05). After UHRF1 knockdown, the expression of WNT3a, GSK3β, and MMP9 in HCT116 cells decreased, whereas the expression of p-β-catenin increased (P < 0.05). The "rescue" experiment with IWP-2 and HLY78 can produce consistent results. (3) Compared with the control group, the cell proliferation, migration, and invasion abilities of the UHRF1 overexpression group were enhanced. After IWP-2 treatment, the cell proliferation, migration, and invasion abilities were inhibited. Knockdown experiment exhibited the reverse results to overexpression experiment. Conclusion UHRF1 may play an important role in the occurrence and development of CRC. UHRF1 overexpression may be a poor prognostic factor for CRC patients. UHRF1 may affect the proliferation, migration, and invasion of CRC cells through the WNT/MMP9 signaling pathway.

Early diets in honeybees have effects on epigenome with consequences on their phenotype. Depending on the early larval diet, either royal jelly (RJ) or royal worker, 2 different female castes are generated from identical genomes, a long-lived queen with fully developed ovaries and a short-lived functionally sterile worker. To generate these prominent physiological and morphological differences between queen and worker, honeybees utilize epigenetic mechanisms which are controlled by nutritional input. These mechanisms include DNA methylation and histone post-translational modifications, mainly histone acetylation. In honeybee larvae, DNA methylation and histone acetylation may be differentially altered by RJ. This diet has biologically active ingredients with inhibitory effects on the de novo methyltransferase DNMT3A or the histone deacetylase 3 HDAC3 to create and maintain the epigenetic state necessary for developing larvae to generate a queen. DNMT and HDAC enzymes work together to induce the formation of a compacted chromatin structure, repressing transcription. Such dialog could be coordinated by their association with other epigenetic factors including the ubiquitin-like containing plant homeodomain (PHD) and really interesting new gene (RING) finger domains 1 (UHRF1). Through its multiple functional domains, UHRF1 acts as an epigenetic reader of both DNA methylation patterns and histone marks. The present review discusses the epigenetic regulation of honeybee's chromatin and how the early diets in honeybees can affect the DNA/histone modifying types of machinery that are necessary to stimulate the larvae to turn into either queen or worker. The review also looks at future directions in epigenetics mechanisms of honeybees, mainly the potential role of UHRF1 in these mechanisms. [ABSTRACT FROM AUTHOR]

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Ubiquitin-like with PHD and RING finger domains 1 (UHRF1) is an essential protein involved in the maintenance of repressive epigenetic marks, ensuring epigenetic stability and fidelity. As an epigenetic regulator, UHRF1 comprises several functional domains (UBL, TTD, PHD, SRA, RING) that are collectively responsible for processes like DNA methylation, histone modification, and DNA repair. UHRF1 is a downstream effector of the RB/E2F pathway, which is nearly universally deregulated in cancer. Under physiological conditions, UHRF1 protein levels are cell cycle-dependent and are post-translationally regulated by proteasomal degradation. Conversely, UHRF1 is overexpressed and serves as an oncogenic driver in multiple cancers. This review focuses on the functional domains of UHRF1, highlighting its key interacting proteins and oncogenic roles in solid tumors including retinoblastoma, osteosarcoma, lung cancer, and breast cancer. Additionally, current therapeutic strategies targeting UHRF1 domains or its interactors are explored, providing an insight on potential clinical applications.

While epigenetic mechanisms such as DNA methylation and histone modification are known to be important for gene suppression, relatively little is still understood about the interplay between these systems. The UHRF1 protein can interact with both DNA methylation and repressive chromatin marks, but its primary function in humans has been unclear. To determine what that was, we first established stable UHRF1 knockdowns (KD) in normal, immortalized human fibroblasts using targeting shRNA, since CRISPR knockouts (KO) were lethal. Although these showed a loss of DNA methylation across the whole genome, transcriptional changes were dominated by the activation of genes involved in innate immune signalling, consistent with the presence of viral RNA from retrotransposable elements (REs). We confirmed using mechanistic approaches that 1) REs were demethylated and transcriptionally activated; 2) this was accompanied by activation of interferons and interferon-stimulated genes and 3) the pathway was conserved across other adult cell types. Restoring UHRF1 in either transient or stable KD systems could abrogate RE reactivation and the interferon response. Notably, UHRF1 itself could also re-impose RE suppression independent of DNA methylation, but not if the protein contained point mutations affecting histone 3 with trimethylated lysine 9 (H3K9me3) binding. Our results therefore show for the first time that UHRF1 can act as a key regulator of retrotransposon silencing independent of DNA methylation.

Sperm‐induced Ca2+ rise is critical for driving oocyte activation and subsequent embryonic development, but little is known about how lasting Ca2+ oscillations are regulated. Here it is shown that NLRP14, a maternal effect factor, is essential for keeping Ca2+ oscillations and early embryonic development. Few embryos lacking maternal NLRP14 can develop beyond the 2‐cell stage. The impaired developmental potential of Nlrp14‐deficient oocytes is mainly caused by disrupted cytoplasmic function and calcium homeostasis due to altered mitochondrial distribution, morphology, and activity since the calcium oscillations and development of Nlrp14‐deficient oocytes can be rescued by substitution of whole cytoplasm by spindle transfer. Proteomics analysis reveal that cytoplasmic UHRF1 (ubiquitin‐like, containing PHD and RING finger domains 1) is significantly decreased in Nlrp14‐deficient oocytes, and Uhrf1‐deficient oocytes also show disrupted calcium homeostasis and developmental arrest. Strikingly, it is found that the mitochondrial Na+/Ca2+ exchanger (NCLX) encoded by Slc8b1 is significantly decreased in the Nlrp14mNull oocyte. Mechanistically, NLRP14 interacts with the NCLX intrinsically disordered regions (IDRs) domain and maintain its stability by regulating the K27‐linked ubiquitination. Thus, the study reveals NLRP14 as a crucial player in calcium homeostasis that is important for early embryonic development. [ABSTRACT FROM AUTHOR]

UHRF1 is an essential chromatin protein required for DNA methylation maintenance, mammalian development, and gene regulation. We investigated the Tandem‐Tudor domain (TTD) of human UHRF1 that is known to bind H3K9me2/3 histones and is a major driver of UHRF1 localization in cells. We verified binding to H3K9me2/3 but unexpectedly discovered stronger binding to H3 peptides and mononucleosomes containing K9me2/3 with additional K4me1. We investigated the combined binding of TTD to H3K4me1‐K9me2/3 versus H3K9me2/3 alone, engineered mutants with specific and differential changes of binding, and discovered a novel read‐out mechanism for H3K4me1 in an H3K9me2/3 context that is based on the interaction of R207 with the H3K4me1 methyl group and on counting the H‐bond capacity of H3K4. Individual TTD mutants showed up to a 10,000‐fold preference for the double‐modified peptides, suggesting that after a conformational change, WT TTD could exhibit similar effects. The frequent appearance of H3K4me1‐K9me2 regions in human chromatin demonstrated in our TTD chromatin pull‐down and ChIP‐western blot data suggests that it has specific biological roles. Chromatin pull‐down of TTD from HepG2 cells and full‐length murine UHRF1 ChIP‐seq data correlate with H3K4me1 profiles indicating that the H3K4me1‐K9me2/3 interaction of TTD influences chromatin binding of full‐length UHRF1. We demonstrate the H3K4me1‐K9me2/3 specific binding of UHRF1‐TTD to enhancers and promoters of cell‐type‐specific genes at the flanks of cell‐type‐specific transcription factor binding sites, and provided evidence supporting an H3K4me1‐K9me2/3 dependent and TTD mediated downregulation of these genes by UHRF1. All these findings illustrate the important physiological function of UHRF1‐TTD binding to H3K4me1‐K9me2/3 double marks in a cellular context. [ABSTRACT FROM AUTHOR]

Propagation of DNA methylation through cell division relies on the recognition of methylated cytosines by UHRF1. In reprogramming of mouse embryonic stem cells to naive pluripotency (also known as ground state), despite high levels of Uhrf1 transcript, the protein is targeted for degradation by the proteasome, leading to DNA methylation loss. We have undertaken an shRNA screen to identify the signalling pathways that converge upon UHRF1 and control its degradation, using UHRF1-GFP fluorescence as readout. Many candidates we identified are key enzymes in regulation of glucose metabolism, nucleotide metabolism and Pi3K/AKT/mTOR pathway. Unexpectedly, while downregulation of all candidates we selected for validation rescued UHRF1 protein levels, we found that in some of the cases this was not sufficient to maintain DNA methylation. This has implications for development, ageing and diseased conditions. Our study demonstrates two separate processes that regulate UHRF1 protein abundance and activity.

Aim: AMPK is the key regulatory kinase mediating the effect of berberine (BBR) and metformin on metabolic improvement. The present study investigated the mechanism of BBR on AMPK activation at low doses, which was different from that of metformin. Methods: Lysosomes were isolated, and AMPK activity assay was performed. PEN2, AXIN1 and UHRF1 were investigated through gain/loss of function approaches, including overexpression, RNA interfering and CRISPR/Cas9-mediated gene knockout. Immunoprecipitation was utilized for detecting the interaction of UHRF1 and AMPKa1 after BBR treatment. Results: BBR activated lysosomal AMPK, but weaker than metformin. AXIN1 mediated BBR's effect on lysosomal AMPK activation, while PEN2 did not. BBR, but not metformin, decreased UHRF1 expression by promoting its degradation. BBR reduced the interaction between UHRF1 and AMPKa1. And overexpression of UHRF1 abolished the effect of BBR on AMPK activation. Conclusion: BBR activated lysosomal AMPK as dependent on AXIN1, but not PEN2. BBR maintained cellular AMPK activity by reducing UHRF1 expression and its interaction with AMPKa1. The mode of action of BBR was different from that of metformin on AMPK activation. [ABSTRACT FROM AUTHOR]

Simple Summary: Mutation of the ataxia-telangiectasia mutated (atm) gene in humans and mice renders them susceptible to tumors due to both its role as a DNA damage sensor acting in pre-malignant cells to activate Tp53 and to its role in sensing and reducing oxidative stress. The oncogene UHRF1 is overexpressed in many cancers and we previously reported that UHRF1 overexpression in zebrafish hepatocytes activates a tumor suppressive pathway dependent on Tp53, resulting in senescence and a small liver which later is bypassed resulting in liver cancer. We tested the hypothesis that Atm was involved in the precancerous small liver phenotype caused by UHRF1 overexpression by generating atm zebrafish mutants. We show that atm mutation and high ROS levels enhanced, whereas antioxidant treatment suppressed, the small liver phenotype in UHRF1 overexpressing larvae. This suggests that the pre-cancerous small liver phenotype caused by UHRF1 overexpression is due to oxidative stress, which is mitigated by Atm. The ataxia-telangiectasia mutated (atm) gene is activated in response to genotoxic stress and leads to activation of the tp53 tumor suppressor gene which induces either senescence or apoptosis as tumor suppressive mechanisms. Atm also serves non-canonical functions in the response to oxidative stress and chromatin reorganization. We previously reported that overexpression of the epigenetic regulator and oncogene Ubiquitin Like with PHD and Ring Finger Domains 1 (UHRF1) in zebrafish hepatocytes resulted in tp53-dependent hepatocyte senescence, a small liver and larval lethality. We investigated the role of atm on UHRF1-mediated phenotypes by generating zebrafish atm mutants. atm−/− adults were viable but had reduction in fertility. Embryos developed normally but were protected from lethality caused by etoposide or H2O2 exposure and failed to fully upregulate Tp53 targets or oxidative stress response genes in response to these treatments. In contrast to the finding that Tp53 prevents the small liver phenotype caused by UHRF1 overexpression, atm mutation and exposure to H2O2 further reduced the liver size in UHRF1 overexpressing larvae whereas treatment with the antioxidant N-acetyl cysteine suppressed this phenotype. We conclude that UHRF1 overexpression in hepatocytes causes oxidative stress, and that loss of atm further enhances this, triggering elimination of these precancerous cells, leading to a small liver. [ABSTRACT FROM AUTHOR]

Background: Oxidative stress is recognized as a key factor in the induction of endothelial dysfunction in diabetes. However, the specific mechanisms have not been fully elucidated. We herein hypothesized that ubiquitin‐like containing PHD and RING finger domains 1 (UHRF1) might have a role in oxidative stress‐induced endothelial cell (EC) apoptosis in diabetes. Methods: Western blot, qPCR, wound healing assay, apoptosis assay, reactive oxygen species (ROS) detection, dual‐luciferase reporter assay, methylation‐specific PCR, bisulfite sequencing PCR and chromatin immunoprecipitation assay were performed. Results: UHRF1 expression levels were significantly decreased in endothelial colony‐forming cells derived from peripheral blood of participants with type 2 diabetes compared with individuals without diabetes. ECs treated with high glucose, palmitate or hydrogen peroxide in vitro also exhibited decreased UHRF1 protein levels. Silencing of UHRF1 led to decreased migration ability and increased apoptosis and ROS production in ECs, which might be related to impaired Kelch‐like ECH‐associated protein 1 (KEAP1)/nuclear factor erythroid 2‐related factor 2 (NRF2)/haeme oxygenase‐1 pathway. Mechanistically, UHRF1 is closely implicated in epigenetic regulation of chromatin modification status at KEAP1 genomic locus via histone acetylation. NRF2 down‐regulation in turn inhibits UHRF1 protein level, which might be due to increased ROS generation. Conclusion: Diabetes‐induced oxidative stress can mediate down‐regulation of UHRF1, which enhances ROS production by regulating KEAP1/p‐NRF2 pathway through histone acetylation and might also form a self‐perpetuating feedback loop with KEAP1/p‐NRF2 to further promote oxidative stress‐induced apoptosis of ECs in diabetes. [ABSTRACT FROM AUTHOR]

Type I interferon (IFN-I) response plays a prominent role in innate immunity, which is frequently modulated during viral infection. Here, we report DNA methylation regulator UHRF1 as a potent negative regulator of IFN-I induction during alphaherpesvirus infection, whereas the viruses in turn regulates the transcriptional expression of UHRF1. Knockdown of UHRF1 in cells significantly increases interferon- b (IFN- b)-mediated gene transcription and viral inhibition against herpes simplex virus 1 (HSV1) and pseudorabies virus (PRV). Mechanistically, UHRF1 deficiency promotes IFN-I production by triggering dsRNA-sensing receptor RIG-I and activating IRF3 phosphorylation. Knockdown of UHRF1 in cells upregulates the accumulation of double-stranded RNA (dsRNA), including host endogenous retroviral sequence (ERV) transcripts, while the treatment of RNase III, known to specifically digest dsRNA, prevents IFN- b induction by siUHRF1. Furthermore, the doubleknockdown assay of UHRF1 and DNA methyltransferase DNMT1 suggests that siUHRF1- mediated DNA demethylation may play an important role in dsRNA accumulation and subsequently IFN induction. These findings establish the essential role of UHRF1 in IFN-Iinduced antiviral immunity and reveal UHRF1 as a potential antivrial target. IMPORTANCE Alphaherpesviruses can establish lifelong infections and cause many diseases in humans and animals, which rely partly on their interaction with IFN-mediated innate immune response. Using alphaherpesviruses PRV and HSV-1 as models, we identi- fied an essential role of DNA methylation regulator UHRF1 in IFN-mediated immunity against virus replication, which unravels a novel mechanism employed by epigenetic factor to control IFN-mediated antiviral immune response and highlight UHRF1, which might be a potential target for antiviral drug development. [ABSTRACT FROM AUTHOR]

The gene dosage at the imprinted Dlk1-Dio3 locus is critical for cell growth and development. A relatively high gene expression within the Dlk1-Dio3 region, especially the active expression of Gtl2, has been identified as the only reliable marker for cell pluripotency. The DNA methylation state of the IG-DNA methylated regions (DMR), which is located upstream of the Gtl2 gene, dominantly contributes to the control of gene expression in the Dlk1-Dio3 locus. However, the precise mechanism underlying the regulation of DNA methylation in the IG-DMR remains largely unknown. Here, we use the F9 embryonal carcinoma cell line, a low pluripotent cell model, to identify the mechanism responsible for DNA methylation in the IG-DMR, and find that the interaction of PGC7 with UHRF1 is involved in maintaining DNA methylation and inducing DNA hypermethylation in the IG-DMR region. PGC7 and UHRF1 cooperatively bind in the IG-DMR to regulate the methylation of DNA and histones in this imprinted region. PGC7 promotes the recruitment of DNMT1 by UHRF1 to maintain DNA methylation in the IG-DMR locus. The interaction between PGC7 and UHRF1 strengthens their binding to H3K9me3 and leads to further enrichment of H3K9me3 in the IG-DMR by recruiting the specific histone methyltransferase SETDB1. Consequently, the abundance of H3K9me3 promotes DNMT3A to bind to the IG-DMR and increases DNA methylation level in this region. In summary, we propose a new mechanism of DNA methylation regulation in the IG-DMR locus and provide further insight into the understanding of the difference in Gtl2 expression levels between high and low pluripotent cells.

PM 2.5 can cause lung cell injury. Due to the complexity and variation of the physical and chemical properties of PM 2.5 , the risk of lung cell injury may depend significantly on the type of atmospheric environment. With a population of 120 million, the Chengdu-Chongqing region in China is the most populated region in the world that experiences both high humidity and low solar radiation (HHLR). However, PM 2.5 -related lung cell injury and treatment strategies in this type of environment are still unclear. Thus, our study focuses on the relationships between the chemical components, lung cell injury effects, and pathogenic mechanisms of PM 2.5 in HHLR (HHLR-PM 2.5). In terms of mass, organic carbon (OC), NO 3 −, SO 4 2−, and NH 4 + are found to be the most significant components of HHLR-PM 2.5. Extracts of HHLR-PM 2.5 significantly inhibit cell viability, stimulate reactive oxygen species (ROS) levels, and trigger inflammation. Utilizing a combination of multi-omics, bioinformatics, and molecular biology, it is found that HHLR-PM 2.5 extracts inhibit E3 ubiquitin-protein ligase (UHRF1) to suppress DNA methyltransferase 1 (DNMT1) and hamper DNA methylation, culminating in lung cell injury. Additionally, integrating transcriptomic data with human disease databases highlights chronic obstructive pulmonary disease (COPD) as a potential lung cell injury-related respiratory affliction induced by HHLR-PM 2.5. This study expands the scientific comprehension of the health risks associated with HHLR-PM 2.5 , deciphers the molecular mechanism of lung cell injury, and provides precise treatment strategies for HHLR-PM 2.5 -induced lung cell injury. [Display omitted] • OC, NO 3 −, SO 4 2− and NH 4 + are the most significant components in HHLR-PM 2.5. • HHLR-PM 2.5 inhibits UHRF1 to disrupt DNA methylation. • HHLR-PM 2.5 mainly causes COPD and its complications. [ABSTRACT FROM AUTHOR]

Ridgetail white prawn, Exopalaemon carinicauda, with high reproductive capacity can reproduce up to three or four generations a year. In exploring the genetic factors affecting the gonadal development of E. carinicauda, we cloned and studied the function of the ubiquitin-like, containing PHD and RING finger domains 1 (uhrf1) gene. The open reading frame of uhrf1 gene was 2286 bp, encoding a total of 761 amino acids. The Uhrf1 has UBL, TTD, PhD, SRA, and ring finger domains that are associated with genome methylation, histone recognition and chromatin modification. According to the phylogenetic analysis, the amino acid sequence of Ec-uhrf1 has the highest similarity with Litopenaeus vannamei uhrf1, and it is a branch of Penaeus monodon and L. vannamei. The real-time quantitative PCR showed that the expression level of uhrf1 was highest in ridgetail white prawn ovarian tissue, which was significantly higher than that of other tissues (P

UHRF1 (ubiquitin-like, containing PHD and RING finger domains, 1) is one of the essential components of mammalian DNA methylation machinery. Chromatin association of UHRF1 is controlled via an interplay between its intramolecular interaction and dual recognition of histone H3 trimethylated at lysine 9 (H3K9me3) and hemimethylated DNA. Here, we report the crystal structure of the N-terminal tandem Tudor domain (TTD) of UHRF1 in complex with the C-terminal polybasic region (PBR). Structural analysis reveals that PBR binding leads to displacement of the TTD-plant homeodomain (PHD) linker, as well as blockage of the H3K9me3-engaging cage, both of which contribute to a chromatin-occluded UHRF1 conformation. Disruption of the TTD-PBR interaction, which is facilitated by the binding of UHRF1 to hemimethylated DNA or regulatory protein USP7, shifts the UHRF1 conformation toward an open state, allowing for efficient H3K9me3 binding. Together, this study provides structural basis for the allosteric regulation of UHRF1.

Pancreatic cancer (PC) is an aggressive malignant disease. Pancreatic ductal adenocarcinoma (PDAC) is a main type of PDAC. The inhibition of aerobic glycolysis in PC cells is one of the approaches to treat PDAC. WD repeat protein 79 (WDR79) acts as a scaffold protein and is involved in several physiological processes. Since WDR79 affects the progression of several types of cancers, whereas its role in PDAC remains unclear. This study was aimed to investigate the role of WDR79 in the progression of PDAC and clarify the mechanism. We found that WDR79 was highly expressed in PDAC cells. Knockdown of WDR79 inhibited the growth as well as the motility of PDAC cells, while overexpression of WDR79 contributed to the growth and motility. The ablation of WDR79 restrained aerobic glycolysis of PDAC cells. Mechanically, we found that WDR79 depletion increased SIRT4 expression by suppressing UHRF1 expression, which counteracted the function of WDR79 in PDAC. We thought that WDR79 could serve as a target for treating PDAC. [ABSTRACT FROM AUTHOR]

While epigenetic mechanisms such as DNA methylation and histone modification are known to be important for gene suppression, relatively little is still understood about the interplay between these systems. The UHRF1 protein can interact with both DNA methylation and repressive chromatin marks, but its primary function in humans has been unclear. To determine what that was, we first established stable UHRF1 knockdowns (KD) in normal, immortalized human fibroblasts using targeting shRNA, since CRISPR knockouts (KO) were lethal. Although these showed a loss of DNA methylation across the whole genome, transcriptional changes were dominated by the activation of genes involved in innate immune signalling, consistent with the presence of viral RNA from retrotransposable elements (REs). We confirmed using mechanistic approaches that 1) REs were demethylated and transcriptionally activated; 2) this was accompanied by activation of interferons and interferon-stimulated genes and 3) the pathway was conserved across other adult cell types. Restoring UHRF1 in either transient or stable KD systems could abrogate RE reactivation and the interferon response. Notably, UHRF1 itself could also re-impose RE suppression independent of DNA methylation, but not if the protein contained point mutations affecting histone 3 with trimethylated lysine 9 (H3K9me3) binding. Our results therefore show for the first time that UHRF1 can act as a key regulator of retrotransposon silencing independent of DNA methylation. [ABSTRACT FROM AUTHOR]