OBJECTIVE: To explore the effect and mechanism of DNA methyltransferase 1 (DNMT1) knockout on the inhibition of acute myeloid leukemia (AML) by natural killer (NK) cells. METHODS: The peripheral blood NK cells of AML patients and controls were collected, and the mRNA and protein level of DNMT1 were measured by PCR and Western blot, respectively. The DNMT1 knockout mice were constructed to obtain NK^DNMT1-/- cells. The NK cells were stimulated with interleukin (IL)-12, IL-15, and IL-18 to construct memory NK cells, and then the interferon-γ (IFN-γ) levels were measured by ELISA. After co-culturing with memory NK cells and HL60 cells, the killing effect of NK^DNMT1-/- cells on HL60 cells was detected by LDH assay. Then, the HL60 cell apoptosis and NK cell NKG2D level were measured by flow cytometry. The perforin and granzyme B protein levels of NK cells were measured by Western blot. The AML model mice were constructed by injecting HL60 cells into the tail vein, meanwhile, memory NK cells were also injected, and then the mouse weights, CD33 positive rates, and survival time were detected. RESULTS: The mRNA and protein levels of DNMT1 in NK cells of AML patients were significantly higher than those in the control group (both P < 0.01), while the IFN-γ level induced by interleukin was significantly lower than that in the control group (P < 0.05). Compared with NK^DNMT1+/+ cells, the ability of NK^DNMT1-/- cells to secrete IFN-γ after interleukin stimulation was significantly increased (P < 0.05). The killing and apoptosis-inducing effects of NK^DNMT1-/- cells on HL60 cells were significantly stronger than those of NK^DNMT1+/+ cells (both P < 0.05). The NKG2D level and expression of perforin and granzyme B of NK^DNMT1-/- cells were significantly increased compared with NK^DNMT1+/+ cells (all P < 0.05). Compared with AML mice injected with NK^DNMT1+/+ cells, AML mice injected with NK^DNMT1-/- cells showed significantly increased body weight, decreased CD33 positive rate, and prolonged survival time (all P < 0.05). CONCLUSION Knocking out DNMT1 can enhance the inhibitory effect of NK cells on AML, which may be related to enhancing NK cell memory function.
Killer Cells, Natural/metabolism* ; Animals ; Leukemia, Myeloid, Acute ; Humans ; DNA (Cytosine-5-)-Methyltransferase 1 ; Mice ; Mice, Knockout ; HL-60 Cells ; Apoptosis ; Interferon-gamma/metabolism* ; Granzymes/metabolism* ; Perforin/metabolism* ; NK Cell Lectin-Like Receptor Subfamily K/metabolism*

The cooccurrence of NPM1, FLT3-ITD, and DNMT3A mutations (i.e., triple mutation) is related to dismal prognosis in patients with acute myeloid leukemia (AML) receiving chemotherapy alone. In this multicenter retrospective cohort study, we aimed to identify whether allogeneic hematopoietic stem cell transplantation (allo-HSCT) could overcome the poor prognosis of DNMT3A^mutNPM1^mutFLT3-ITD^mut AML across four transplant centers in China. Fifty-three patients with triple-mutated AML receiving allo-HSCT in complete remission were enrolled. The 1.5-year probabilities of relapse, leukemia-free survival, and overall survival after allo-HSCT were 11.9%, 80.3%, and 81.8%, respectively. Multivariate analysis revealed that more than one course of induction chemotherapy and allo-HSCT beyond CR1 were associated with poor survival. To our knowledge, this work is the largest study to explore the up-to-date undefined role of allo-HSCT in patients with triple-mutated AML. Our real-world data suggest that allo-HSCT could overcome the poor prognosis of DNMT3A^mutNPM1^mutFLT3-ITD^mut in AML.
Humans ; Nucleophosmin ; Leukemia, Myeloid, Acute/mortality* ; Hematopoietic Stem Cell Transplantation/methods* ; Male ; Female ; DNA Methyltransferase 3A ; Adult ; China ; Retrospective Studies ; DNA (Cytosine-5-)-Methyltransferases/genetics* ; Middle Aged ; Prognosis ; fms-Like Tyrosine Kinase 3/genetics* ; Mutation ; Young Adult ; Transplantation, Homologous ; Nuclear Proteins/genetics* ; Adolescent ; Aged

RNA methylation is a key process in the epigenetic regulation of post-transcriptional gene expression.5-Methylcytosine(m⁵C)is a type of RNA methylation,commonly existing in eukaryotic mRNA and non-coding RNAs.It mainly regulates transfer RNA stability,ribosomal RNA assembly,and mRNA translation,stability,and translation.RNA methylation is dynamically reversible and regulated by methyltransferase,demethylase,and methylation recognition protein.It has been confirmed that aberrant m⁵C RNA methylation is involved in the pathogenesis of non-neoplastic kidney diseases.This article summarizes the current progress of m⁵C RNA methylation associated with non-neoplastic acute and chronic kidney diseases,aiming to provide potential targets for the diagnosis and treatment of such diseases.
Humans ; Methylation ; 5-Methylcytosine/metabolism* ; Kidney Diseases/metabolism* ; Epigenesis, Genetic ; RNA Methylation

Conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) by ten-eleven translocation (TET) family proteins leads to the accumulation of 5hmC in the central nervous system; however, the role of 5hmC in the postnatal brain and how its levels and target genes are regulated by TETs remain elusive. We have generated mice that lack all three Tet genes specifically in postnatal excitatory neurons. These mice exhibit significantly reduced 5hmC levels, altered dendritic spine morphology within brain regions crucial for cognition, and substantially impaired spatial and associative memories. Transcriptome profiling combined with epigenetic mapping reveals that a subset of genes, which display changes in both 5hmC/5mC levels and expression patterns, are involved in synapse-related functions. Our findings provide insight into the role of postnatally accumulated 5hmC in the mouse brain and underscore the impact of 5hmC modification on the expression of genes essential for synapse development and function.
Animals ; Brain/growth & development* ; 5-Methylcytosine/metabolism* ; Mice ; Synapses/genetics* ; Proto-Oncogene Proteins/metabolism* ; DNA-Binding Proteins/metabolism* ; Dioxygenases/metabolism* ; Cognition/physiology* ; Gene Expression ; Mixed Function Oxygenases/metabolism* ; Epigenesis, Genetic ; Mice, Knockout ; Mice, Inbred C57BL

Ten-eleven translocation 1 (TET1) protein is an alpha-ketoglutaric acid (α-KG) and Fe²⁺-dependent dioxygenase. It plays a role in the active demethylation of DNA by hydroxylation of 5-methyl-cytosine (5-mC) to 5-hydroxymethyl-cytosine (5-hmC). Ten-eleven translocation 1 (TET1) protein is involved in maintaining genome methylation homeostasis and epigenetic regulation. Abnormally expressed TET1 and 5-mC oxidative derivatives have become potential markers in various biological and pathological processes and a research focus in the fields of embryonic development and malignant tumors. This paper introduces the structure and demethylation mechanism of TET1, reviews the research status of epigenetic regulation by TET1 in embryonic development, immune responses, stem cell regulation, cancer progression, and nervous system development, and briefs the upstream regulatory mechanism of TET1, hoping to provide new inspirations for further research in related fields.
Proto-Oncogene Proteins/genetics* ; Epigenesis, Genetic ; Humans ; DNA-Binding Proteins/metabolism* ; DNA Methylation ; Mixed Function Oxygenases/metabolism* ; 5-Methylcytosine/analogs & derivatives* ; Animals ; Embryonic Development/genetics* ; Neoplasms/genetics* ; Dioxygenases/metabolism*

OBJECTIVE: To observe the clinical significance of translocator proteins (TSPO) gene in the treatment of FLT3-ITD/DNMT3A R882 double-mutated acute myeloid leukemia (AML). METHODS: Seventy-six patients with AML hospitalized in the Department of Hematology of the Affiliated People's Hospital of Ningbo University from June 2018 to June 2020 were selected, including 34 patients with FLT3-ITD mutation, 27 patients with DNMT3A R882 mutation, 15 patients with FLT3-ITD/DNMT3A R882 double mutation, as well as 19 patients with immune thrombocytopenia (ITP) hospitalized during the same period as control group. RNA was routinely extracted from 3 ml bone marrow retained during bone puncture, and TSPO gene expression was detected by transcriptome sequencing (using 2-deltadeltaCt calculation). RESULTS: The expression of TSPO gene in FLT3-ITD group and DNMT3A R882 group at first diagnosis was 2.02±1.04 and 1.85±0.76, respectively, which were both higher than 1.00±0.06 in control group, but the differences were not statistically significant (P=0.671, P=0.821). The expression of TSPO gene in the FLT3-ITD/DNMT3A R882 group was 3.98±1.07, wich was significantly higher than that in the FLT3-ITD group and DNMT3A R882 group, the differences were statistically significant (P=0.032, P=0.021). The expression of TSPO gene in patients who achieved complete response after chemotherapy in the FLT3-ITD/DNMT3A R882 group was 1.19±0.87, which was significantly lower than that at first diagnosis, and the difference was statistically significant (P=0.011). CONCLUSION TSPO gene may be used as an indicator of efficacy in FLT3-ITD /DNMT3A R882 double-mutated AML.
Humans ; DNA (Cytosine-5-)-Methyltransferases/genetics* ; DNA Methyltransferase 3A ; Mutation ; Leukemia, Myeloid, Acute/drug therapy* ; Nucleophosmin ; Prognosis ; fms-Like Tyrosine Kinase 3/genetics* ; Receptors, GABA/therapeutic use*

Approximately 140 million people worldwide are homozygous carriers of APOE4 (ε4), a strong genetic risk factor for late onset familial and sporadic Alzheimer's disease (AD), 91% of whom will develop AD at earlier age than heterozygous carriers and noncarriers. Susceptibility to AD could be reduced by targeted editing of APOE4, but a technical basis for controlling the off-target effects of base editors is necessary to develop low-risk personalized gene therapies. Here, we first screened eight cytosine base editor variants at four injection stages (from 1- to 8-cell stage), and found that FNLS-YE1 variant in 8-cell embryos achieved the comparable base conversion rate (up to 100%) with the lowest bystander effects. In particular, 80% of AD-susceptible ε4 allele copies were converted to the AD-neutral ε3 allele in human ε4-carrying embryos. Stringent control measures combined with targeted deep sequencing, whole genome sequencing, and RNA sequencing showed no DNA or RNA off-target events in FNLS-YE1-treated human embryos or their derived stem cells. Furthermore, base editing with FNLS-YE1 showed no effects on embryo development to the blastocyst stage. Finally, we also demonstrated FNLS-YE1 could introduce known protective variants in human embryos to potentially reduce human susceptivity to systemic lupus erythematosus and familial hypercholesterolemia. Our study therefore suggests that base editing with FNLS-YE1 can efficiently and safely introduce known preventive variants in 8-cell human embryos, a potential approach for reducing human susceptibility to AD or other genetic diseases.
Humans ; Apolipoprotein E4/genetics* ; Cytosine ; Mutation ; Blastocyst ; Heterozygote ; Gene Editing ; CRISPR-Cas Systems

RNA methylation is of great significance in the regulation of gene expression, among which the more important methylation modifiers are N6-methyladenosine (m6A) and 5-methylcytosine (m5C). The methylation process is mainly regulated by 3 kinds of proteins: methyltransferase, demethylase, and reader. m6A, m5C, and their related proteins have high abundance in the brain, and they have important roles in the development of the nervous system and the repair and remodeling of the vascular system. The neurovascular unit (NVU) is a unit of brain structure and function composed of neurons, capillaries, astrocytes, supporting cells, and extracellular matrix. The local microenvironment for NVU has an important role in nerve cell function repair, and the remodeling of NVU is of great significance in the prognosis of various neurological diseases.
5-Methylcytosine ; Adenosine/metabolism* ; Methylation ; Methyltransferases/metabolism* ; RNA

The methylation of cytosine is one of the most fundamental epigenetic modifications in mammalian genomes, and is involved in multiple crucial processes including gene expression, cell differentiation, embryo development and oncogenesis. In the past, DNA methylation was thought to be an irreversible process, which could only be diluted passively through DNA replication. It is now becoming increa-singly obvious that DNA demethylation can be an active process and plays a crucial role in biological processes. Ten eleven translocation (TET) proteins are the key factors modulating DNA demethylation. This family contains three members: TET1, TET2 and TET3. Although three TET proteins have relatively conserved catalytic domains, their roles in organisms are not repeated, and their expression has significant cell/organ specificity. TET1 is mainly expressed in embryonic stem cells, TET2 is mainly expressed in hematopoietic system, and TET3 is widely expressed in cerebellum, cortex and hippocampus. This family catalyzes 5-methylcytosine to 5-hydroxymethylcytosine and other oxidative products, reactivates silenced-gene expression, in turn maintains stem cell pluripotency and regulates lineage specification. With the development of tissue engineering, organ transplantation, autologous tissue transplantation and artificial prosthesis have been widely used in clinical treatment, but these technologies have limitations. Regenerative medicine, which uses stem cells and stem cell related factors for treatment, may provide alternative therapeutic strategies for multiple diseases. Among all kinds of human stem cells, adipose-derived stem cells (ADSCs) are the most prospective stem cell lineage since they have no ethical issues and can be easily obtained with large quantities. To date, ADSCs have been shown to have strong proli-feration capacity, secrete numerous soluble factors and have multipotent differentiation ability. However, the underlying mechanism of the proliferation, secretion, acquired pluripotency, and lineage specific differentiation of ADSCs are still largely unknown. Some studies have explored the role of epigenetic regulation and TET protein in embryonic stem cells, but little is known about its role in ADSCs. By studying the roles of TET proteins and 5-hydroxymethylcytosine in ADSCs, we could provide new theoretical foundation for the clinical application of ADSCs and the stem cell-based therapy. In the future, combined with bioprinting technology, ADSCs may be used in tissue and organ regeneration, plastic surgery reconstruction and other broader fields.
5-Methylcytosine/analogs & derivatives* ; Animals ; DNA Methylation ; DNA-Binding Proteins/genetics* ; Epigenesis, Genetic ; Humans ; Mixed Function Oxygenases/metabolism* ; Prospective Studies ; Proto-Oncogene Proteins/metabolism* ; Regenerative Medicine ; Stem Cells/metabolism*

The CRISPR system is able to accomplish precise base editing in genomic DNA, but relies on the cellular homology-directed recombination repair pathway and is therefore extremely inefficient. Base editing is a new genome editing technique developed based on the CRISPR/Cas9 system. Two base editors (cytosine base editor and adenine base editor) were developed by fusing catalytically disabled nucleases with different necleobase deaminases. These two base editors are able to perform C>T (G>A) or A>G (T>C) transition without generating DNA double-stranded breaks. The base editing technique has been widely used in gene therapy, animal models construction, precision animal breeding and gene function analysis, providing a powerful tool for basic and applied research. This review summarized the development process, technical advantages, current applications, challenges and perspectives for base editing technique, aiming to help the readers better understand and use the base editing technique.
Adenine ; Animals ; CRISPR-Cas Systems/genetics* ; Cytosine ; DNA Breaks, Double-Stranded ; Gene Editing