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Cell Death & Disease Jun 2023Tau hyperphosphorylation in hippocampal neurons has an important pathogenetic role in the development of diabetic cognitive dysfunction. N-methyladenosine (mA)...
High glucose induces tau hyperphosphorylation in hippocampal neurons via inhibition of ALKBH5-mediated Dgkh mA demethylation: a potential mechanism for diabetic cognitive dysfunction.
Tau hyperphosphorylation in hippocampal neurons has an important pathogenetic role in the development of diabetic cognitive dysfunction. N-methyladenosine (mA) methylation is the most common modification of eukaryotic mRNA and is involved in regulating diverse biological processes. However, the role of mA alteration in tau hyperphosphorylation of hippocampus neurons has not been reported. We found lower ALKBH5 expression in the hippocampus of diabetic rats and in HN-h cells with high-glucose intervention, accompanied by tau hyperphosphorylation. ALKBH5 overexpression significantly reversed tau hyperphosphorylation in high-glucose-stimulated HN-h cells. Furthermore, we found and confirmed by mA-mRNA epitope transcriptome microarray and transcriptome RNA sequencing coupled with methylated RNA immunoprecipitation that ALKBH5 regulates the mA modification of Dgkh mRNA. High glucose inhibited the demethylation modification of Dgkh by ALKBH5, resulting in decreases in Dgkh mRNA and protein levels. Overexpression of Dgkh reversed tau hyperphosphorylation in HN-h cells after high-glucose stimulation. Overexpression of Dgkh by adenovirus suspension injection into the bilateral hippocampus of diabetic rats significantly ameliorated tau hyperphosphorylation and diabetic cognitive dysfunction. In addition, ALKBH5 targeted Dgkh to activate PKC-α, leading to tau hyperphosphorylation under high-glucose conditions. The results of this study reveal that high glucose suppresses the demethylation modification of Dgkh by ALKBH5, which downregulates Dgkh and leads to tau hyperphosphorylation through activation of PKC-α in hippocampal neurons. These findings may indicate a new mechanism and a novel therapeutic target for diabetic cognitive dysfunction.
Topics: Animals; Rats; Diabetes Mellitus, Experimental; Neurons; RNA, Messenger; Cognitive Dysfunction; Hippocampus; Demethylation; Glucose
PubMed: 37385994
DOI: 10.1038/s41419-023-05909-7 -
Biochemical Society Transactions Feb 2021Alterations in global epigenetic signatures on chromatin are well established to contribute to tumor initiation and progression. Chromatin methylation status modulates... (Review)
Review
Alterations in global epigenetic signatures on chromatin are well established to contribute to tumor initiation and progression. Chromatin methylation status modulates several key cellular processes that maintain the integrity of the genome. KDM4A, a demethylase that belongs to the Fe-II dependent dioxygenase family that uses α-ketoglutarate and molecular oxygen as cofactors, is overexpressed in several cancers and is associated with an overall poor prognosis. KDM4A demethylates lysine 9 (H3K9me2/3) and lysine 36 (H3K36me3) methyl marks on histone H3. Given the complexity that exists with these marks on chromatin and their effects on transcription and proliferation, it naturally follows that demethylation serves an equally important role in these cellular processes. In this review, we highlight the role of KDM4A in transcriptional modulation, either dependent or independent of its enzymatic activity, arising from the amplification of this demethylase in cancer. KDM4A modulates re-replication of distinct genomic loci, activates cell cycle inducers, and represses proteins involved in checkpoint control giving rise to proliferative damage, mitotic disturbances and chromosomal breaks, ultimately resulting in genomic instability. In parallel, emerging evidence of non-nuclear substrates of epigenetic modulators emphasize the need to investigate the role of KDM4A in regulating non-nuclear substrates and evaluate their contribution to genomic instability in this context. The existence of promising KDM-specific inhibitors makes these demethylases an attractive target for therapeutic intervention in cancers.
Topics: Animals; Cell Transformation, Neoplastic; Genomic Instability; Histones; Humans; Jumonji Domain-Containing Histone Demethylases; Methylation; Neoplasms; Protein Processing, Post-Translational; Signal Transduction
PubMed: 33492339
DOI: 10.1042/BST20191219 -
Nature Communications Mar 2021Cancer stem cells (CSCs) are a small but critical cell population for cancer biology since they display inherent resistance to standard therapies and give rise to...
Cancer stem cells (CSCs) are a small but critical cell population for cancer biology since they display inherent resistance to standard therapies and give rise to metastases. Despite accruing evidence establishing a link between deregulation of epitranscriptome-related players and tumorigenic process, the role of messenger RNA (mRNA) modifications in the regulation of CSC properties remains poorly understood. Here, we show that the cytoplasmic pool of fat mass and obesity-associated protein (FTO) impedes CSC abilities in colorectal cancer through its N,2'-O-dimethyladenosine (mA) demethylase activity. While mA is strategically located next to the mG-mRNA cap, its biological function is not well understood and has not been addressed in cancer. Low FTO expression in patient-derived cell lines elevates mA level in mRNA which results in enhanced in vivo tumorigenicity and chemoresistance. Inhibition of the nuclear mA methyltransferase, PCIF1/CAPAM, fully reverses this phenotype, stressing the role of mA modification in stem-like properties acquisition. FTO-mediated regulation of mA marking constitutes a reversible pathway controlling CSC abilities. Altogether, our findings bring to light the first biological function of the mA modification and its potential adverse consequences for colorectal cancer management.
Topics: Adaptor Proteins, Signal Transducing; Adenosine; Alpha-Ketoglutarate-Dependent Dioxygenase FTO; Cell Line, Tumor; Cell Nucleus; Colorectal Neoplasms; Cytoplasm; Demethylation; Gene Expression Regulation, Neoplastic; Gene Silencing; Humans; Methyltransferases; Nuclear Proteins; RNA, Messenger
PubMed: 33741917
DOI: 10.1038/s41467-021-21758-4 -
Clinical and Translational Medicine Sep 2023Cysteine dioxygenase 1 (CDO1) is frequently methylated, and its expression is decreased in many human cancers including breast cancer (BC). However, the functional and...
BACKGROUND
Cysteine dioxygenase 1 (CDO1) is frequently methylated, and its expression is decreased in many human cancers including breast cancer (BC). However, the functional and mechanistic aspects of CDO1 inactivation in BC are poorly understood, and the diagnostic significance of serum CDO1 methylation remains unclear.
METHODS
We performed bioinformatics analysis of publicly available databases and employed MassARRAY EpiTYPER methylation sequencing technology to identify differentially methylated sites in the CDO1 promoter of BC tissues compared to normal adjacent tissues (NATs). Subsequently, we developed a MethyLight assay using specific primers and probes for these CpG sites to detect the percentage of methylated reference (PMR) of the CDO1 promoter. Furthermore, both LentiCRISPR/dCas9-Tet1CD-based CDO1-targeted demethylation system and CDO1 overexpression strategy were utilized to detect the function and underlying mechanism of CDO1 in BC. Finally, the early diagnostic value of CDO1 as a methylation biomarker in BC serum was evaluated.
RESULTS
CDO1 promoter was hypermethylated in BC tissues, which was related to poor prognosis (p < .05). The CRISPR/dCas9-based targeted demethylation system significantly reduced the PMR of CDO1 promotor and increased CDO1 expression in BC cells. Consequently, this leads to suppression of cell proliferation, migration and invasion. Additionally, we found that CDO1 exerted a tumour suppressor effect by inhibiting the cell cycle, promoting cell apoptosis and ferroptosis. Furthermore, we employed the MethyLight to detect CDO1 PMR in BC serum, and we discovered that serum CDO1 methylation was an effective non-invasive biomarker for early diagnosis of BC.
CONCLUSIONS
CDO1 is hypermethylated and acts as a tumour suppressor gene in BC. Epigenetic editing of abnormal CDO1 methylation could have a crucial role in the clinical treatment and prognosis of BC. Additionally, serum CDO1 methylation holds promise as a valuable biomarker for the early diagnosis and management of BC.
Topics: Humans; Clustered Regularly Interspaced Short Palindromic Repeats; Cysteine Dioxygenase; Apoptosis; Cell Cycle; Demethylation; Neoplasms
PubMed: 37740473
DOI: 10.1002/ctm2.1423 -
Communications Biology Dec 2023N-methyladenosine (mA) plays a crucial role in the development and functional homeostasis of the central nervous system. The fat mass and obesity-associated (FTO) gene,...
N-methyladenosine (mA) plays a crucial role in the development and functional homeostasis of the central nervous system. The fat mass and obesity-associated (FTO) gene, which is highly expressed in the hypothalamus, is closely related to female pubertal development. In this study, we found that mA methylation decreased in the hypothalamus gradually with puberty and decreased in female rats with precocious puberty. FTO expression was increased at the same time. Methylated RNA immunoprecipitation sequencing (MeRIP-seq) showed that the mA methylation of PLCβ, a key enzyme of the Ca signalling pathway, was decreased significantly in the hypothalamus in precocious rats. Upregulating FTO increased PLCβ3 expression and activated the Ca signalling pathway, which promoted GnRH expression. Dual-luciferase reporter and MeRIP-qPCR assays confirmed that FTO regulated mA demethylation of PLCβ and promoted PLCβ expression. Upon overexpressing FTO in the hypothalamic arcuate nucleus (ARC) in female rats, we observed advanced puberty onset. Meanwhile, PLCβ and GnRH expression in the hypothalamus increased significantly, and the Ca signalling pathway was activated. Our study demonstrates that FTO enhances GnRH expression, which promotes puberty onset, by regulating mA demethylation of PLCβ3 and activating the Ca signalling pathway.
Topics: Animals; Female; Rats; Demethylation; Gonadotropin-Releasing Hormone; Hypothalamus; Methylation; Signal Transduction
PubMed: 38129517
DOI: 10.1038/s42003-023-05677-2 -
Developmental Cell Oct 2021Epigenetic mechanisms contribute to the regulation of cell differentiation and function. Vascular smooth muscle cells (SMCs) are specialized contractile cells that...
Epigenetic mechanisms contribute to the regulation of cell differentiation and function. Vascular smooth muscle cells (SMCs) are specialized contractile cells that retain phenotypic plasticity even after differentiation. Here, by performing selective demethylation of histone H3 lysine 4 di-methylation (H3K4me2) at SMC-specific genes, we uncovered that H3K4me2 governs SMC lineage identity. Removal of H3K4me2 via selective editing in cultured vascular SMCs and in murine arterial vasculature led to loss of differentiation and reduced contractility due to impaired recruitment of the DNA methylcytosine dioxygenase TET2. H3K4me2 editing altered SMC adaptative capacities during vascular remodeling due to loss of miR-145 expression. Finally, H3K4me2 editing induced a profound alteration of SMC lineage identity by redistributing H3K4me2 toward genes associated with stemness and developmental programs, thus exacerbating plasticity. Our studies identify the H3K4me2-TET2-miR145 axis as a central epigenetic memory mechanism controlling cell identity and function, whose alteration could contribute to various pathophysiological processes.
Topics: Adaptation, Physiological; Animals; Cell Differentiation; Cell Line; Cell Lineage; DNA Methylation; DNA-Binding Proteins; Demethylation; Dioxygenases; Epigenesis, Genetic; Epigenomics; Gene Expression; Gene Expression Regulation; Histones; Homeostasis; Humans; Male; Mice; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Vascular Remodeling
PubMed: 34582749
DOI: 10.1016/j.devcel.2021.09.001 -
Epigenetics & Chromatin Oct 2023Vitamin C (vitC) enhances the activity of 2-oxoglutarate-dependent dioxygenases, including TET enzymes, which catalyse DNA demethylation, and Jumonji-domain histone...
BACKGROUND
Vitamin C (vitC) enhances the activity of 2-oxoglutarate-dependent dioxygenases, including TET enzymes, which catalyse DNA demethylation, and Jumonji-domain histone demethylases. The epigenetic remodelling promoted by vitC improves the efficiency of induced pluripotent stem cell derivation, and is required to attain a ground-state of pluripotency in embryonic stem cells (ESCs) that closely mimics the inner cell mass of the early blastocyst. However, genome-wide DNA and histone demethylation can lead to upregulation of transposable elements (TEs), and it is not known how vitC addition in culture media affects TE expression in pluripotent stem cells.
RESULTS
Here we show that vitC increases the expression of several TE families, including evolutionarily young LINE-1 (L1) elements, in mouse ESCs. We find that TET activity is dispensable for L1 upregulation, and that instead it occurs largely as a result of H3K9me3 loss mediated by KDM4A/C histone demethylases. Despite increased L1 levels, we did not detect increased somatic insertion rates in vitC-treated cells. Notably, treatment of human ESCs with vitC also increases L1 protein levels, albeit through a distinct, post-transcriptional mechanism.
CONCLUSION
VitC directly modulates the expression of mouse L1s and other TEs through epigenetic mechanisms, with potential for downstream effects related to the multiple emerging roles of L1s in cellular function.
Topics: Humans; Animals; Mice; Ascorbic Acid; Mouse Embryonic Stem Cells; Long Interspersed Nucleotide Elements; DNA Methylation; Histone Demethylases; DNA; Demethylation; Jumonji Domain-Containing Histone Demethylases
PubMed: 37845773
DOI: 10.1186/s13072-023-00514-6 -
Clinical Epigenetics Jul 2023Adolescent idiopathic scoliosis (AIS) is characterized by low lean mass without vertebral deformity. The cause-and-effect relationship between scoliosis and paraspinal...
BACKGROUND
Adolescent idiopathic scoliosis (AIS) is characterized by low lean mass without vertebral deformity. The cause-and-effect relationship between scoliosis and paraspinal muscle imbalance has long puzzled researchers. Although FTO has been identified as a susceptibility gene for AIS, its potential role in the asymmetry of paraspinal muscles has not been fully elucidated.
METHODS
We investigated the role of Fto in murine myoblast proliferation, migration, and myogenic differentiation. We examined its precise regulatory influence on murine muscle fiber remodeling in vitro and in vivo. We identified the downstream target gene of Fto by screening key regulators of murine muscle fiber remodeling and identified its mA reader. Deep paraspinal muscle samples were obtained from the concave and convex sides of AIS patients with or without Schroth exercises, and congenital scoliosis served as a control group. We compared the content of type I fibers, expression patterns of fast- and slow-type genes, and levels of FTO expression.
RESULTS
FTO contributed to maintain the formation of murine slow-twitch fibers both in vitro and in vivo. These effects were mediated by the demethylation activity of FTO, which specifically demethylated NFATC1 and prevented YTHDF2 from degrading it. We found a significant reduction in type I fibers, mRNA levels of MYH7 and MYH7B, and expression of FTO on the concave side of AIS. The percentage of type I fibers showed a positive correlation with the expression level of FTO. The asymmetric patterns observed in AIS were consistent with those seen in congenital scoliosis, and the asymmetry of FTO expression and fiber type in AIS was largely restored by Schroth exercises.
CONCLUSIONS
FTO supports the formation of murine slow-twitch fibers in an NFATC1-YTHDF2 dependent manner. The consistent paraspinal muscle features seen in AIS and congenital scoliosis, as well as the reversible pattern of muscle fibers and expression of FTO in AIS suggest that FTO may contribute to the muscle fiber remodeling secondary to scoliosis.
Topics: Adolescent; Humans; Animals; Mice; Scoliosis; DNA Methylation; Muscle Fibers, Skeletal; Transcription Factors; Paraspinal Muscles; NFATC Transcription Factors; Alpha-Ketoglutarate-Dependent Dioxygenase FTO; RNA-Binding Proteins
PubMed: 37408034
DOI: 10.1186/s13148-023-01526-5 -
Nature Communications Nov 2021Exhausted CD8 T cells are key targets of immune checkpoint blockade therapy and their ineffective reinvigoration limits the durable benefit in some cancer patients....
Exhausted CD8 T cells are key targets of immune checkpoint blockade therapy and their ineffective reinvigoration limits the durable benefit in some cancer patients. Here, we demonstrate that histone demethylase LSD1 acts to enforce an epigenetic program in progenitor exhausted CD8 T cells to antagonize the TCF1-mediated progenitor maintenance and to promote terminal differentiation. Consequently, genetic perturbation or small molecules targeting LSD1 increases the persistence of the progenitor exhausted CD8 T cells, which provide a sustained source for the proliferative conversion to numerically larger terminally exhausted T cells with tumor-killing cytotoxicity, thereby leading to effective and durable responses to anti-PD1 therapy. Collectively, our findings provide important insights into epigenetic mechanisms that regulate T cell exhaustion and have important implications for durable immunotherapy.
Topics: Animals; CD8-Positive T-Lymphocytes; Cell Line, Tumor; Cell Proliferation; DNA Demethylation; Disease Models, Animal; Drug Resistance, Neoplasm; Epigenesis, Genetic; Female; Gene Expression Regulation, Neoplastic; HEK293 Cells; Hepatocyte Nuclear Factor 1-alpha; Histone Demethylases; Humans; Immune Checkpoint Inhibitors; Lymphocytes, Tumor-Infiltrating; Male; Mice; Mice, Transgenic; Neoplasms; Primary Cell Culture; Programmed Cell Death 1 Receptor; Recombinant Proteins
PubMed: 34819502
DOI: 10.1038/s41467-021-27179-7 -
JCI Insight Oct 2023Abnormal macrophage polarization is generally present in autoimmune diseases. Overwhelming M1 macrophage activation promotes the continuous progression of inflammation,...
Abnormal macrophage polarization is generally present in autoimmune diseases. Overwhelming M1 macrophage activation promotes the continuous progression of inflammation, which is one of the reasons for the development of autoimmune diseases. However, the underlying mechanism is still unclear. Here we explore the function of Regulatory factor X1 (RFX1) in macrophage polarization by constructing colitis and lupus-like mouse models. Both in vivo and in vitro experiments confirmed that RFX1 can promote M1 and inhibit M2 macrophage polarization. Furthermore, we found that RFX1 promoted DNA demethylation of macrophage polarization-related genes by increasing APOBEC3A/Apobec3 expression. We identified a potential RFX1 inhibitor, adenosine diphosphate (ADP), providing a potential strategy for treating autoimmune diseases.
Topics: Animals; Mice; Autoimmune Diseases; DNA Demethylation; Inflammation; Macrophage Activation; Macrophages; Regulatory Factor X1
PubMed: 37733446
DOI: 10.1172/jci.insight.165546