TET1 Research Articles

TET2 confers a mechanistic link of microRNA-210 and mtROS in hypoxia-suppressed spontaneous transient outward currents in uterine arteries of pregnant sheep.

Hypoxia during pregnancy impairs uterine vascular adaptation via microRNA-210 (miR-210)-mediated mitochondrial dysfunction and mitochondrial reactive oxygen species (mtROS) generation. TET methylcytosine dioxygenase 2 (TET2) participates in regulating inflammation and oxidative stress and its deficiency contributes to the pathogenesis of multiple cardiovascular diseases. Thus, we hypothesize a role of TET2 in hypoxia/miR-210-mediated mtROS suppressing spontaneous transient outward currents (STOCs) in uterine arteries. We found that gestational hypoxia downregulated TET2 in uterine arteries of pregnant sheep and TET2 was a target of miR-210. Knockdown of TET2 with small interfering RNAs suppressed mitochondrial respiration, increased mtROS, inhibited STOCs and elevated myogenic tone. By contrast, overexpression of TET2 negated hypoxia- and miR-210-induced mtROS. The effects of TET2 knockdown in uterine arteries on mtROS, STOCs and myogenic contractions were blocked by the mitochondria-targeted antioxidant MitoQ. In addition, the recovery effects of inhibiting endogenous miR-210 with miR-210-LNA on hypoxia-induced suppression of STOCs and augmentation of myogenic tone were reversed by TET2 knockdown in uterine arteries. Together, our study reveals a novel mechanistic link between the miR-210-TET2-mtROS pathway and inhibition of STOCs and provides new insights into the understanding of uterine vascular maladaptation in pregnancy complications associated with gestational hypoxia. KEY POINTS: Gestational hypoxia downregulates TET methylcytosine dioxygenase 2 (TET2) in uterine arteries of pregnant sheep. TET2 is a downstream target of microRNA-210 (miR-210) and miR-210mediates hypoxia-induced TET2 downregulation. Knockdown of TET2 in uterine arteries recapitulates the effect of hypoxia and miR-210 and impairs mitochondrial bioenergetics and increases mitochondrial reactive oxygen species (mtROS) . Overexpression of TET2 negates the effect of hypoxia and miR-210 on increasing mtROS. TET2 knockdown reiterates the effect of hypoxia and miR-210 and suppresses spontaneous transient outward currents (STOCs) and elevates myogenic tone, and these effects are blocked by MitoQ. Knockdown of TET2 reverses the miR-210-LNA-induced reversal of the effects of hypoxia on STOCs and myogenic tone in uterine arteries.

Melatonin protects retinal integrity through mediated immune homeostasis in the sodium iodate-induced mouse model of age-related macular degeneration

BackgroundAge-related macular degeneration is the leading cause of visual deficiency in older adults worldwide. Melatonin (MT) can potentially reduce retinal deterioration. However, the mechanism by which MT mediates regulatory T cells (Tregs) in the retina is not yet fully understood. MethodsThe transcriptome profiles of aged or young human retinal tissues from the GEO database were analyzed for MT-related gene expression. The pathological changes in the retina in the NaIO3-induced mouse model were quantitatively determined by staining with hematoxylin and eosin. Retinal whole-mounting immunofluorescence staining was conducted to determine the expression of the Treg-specific marker FOXP3. The phenotypes of M1/M2 macrophages were representing related gene markers in the retina. The GEO database includes biopsies from patients with retinal detachment for ENPTD1, NT5E, and TET2 gene expression. A pyrosequencing assay was performed for NT5E DNA methylation on human primary Tregs, and siTET2 transfection engineering was used. ResultsMT synthesis-related genes in retinal tissue may be affected by age. Our study shows that MT can effectively restore NaIO3-induced retinopathy and maintain retinal structural integrity. Importantly, MT may assist the conversion of M1 to M2 macrophages to promote tissue repair, which may be caused by the increased infiltration of Tregs. Moreover, MT treatment may upregulate TET2, and further NT5E demethylation is associated with Treg recruitment in the retinal microenvironment. ConclusionsOur findings suggest that MT can effectively ameliorate retinal degeneration and regulate immune homeostasis via Tregs. Modulation of the immune response may provide a key therapeutic strategy.

Epigenetic Differences Arise in Endothelial Cells Responding to Cobalt–Chromium

Cobalt-chromium (Co-Cr)-based alloys are emerging with important characteristics for use in dentistry, but the knowledge of epigenetic mechanisms in endothelial cells has barely been achieved. In order to address this issue, we have prepared a previously Co-Cr-enriched medium to further treat endothelial cells (HUVEC) for up to 72 h. Our data show there is important involvement with epigenetic machinery. Based on the data, it is believed that methylation balance in response to Co-Cr is finely modulated by DNMTs (DNA methyltransferases) and TETs (Tet methylcytosine dioxygenases), especially DNMT3B and both TET1 and TET2. Additionally, histone compaction HDAC6 (histone deacetylase 6) seems to develop a significant effect in endothelial cells. The requirement of SIRT1 seems to have a crucial role in this scenario. SIRT1 is associated with a capacity to modulate the expression of HIF-1α in response to hypoxia microenvironments, thus presenting a protective effect. As mentioned previously, cobalt is able to prevent HIF1A degradation and maintain hypoxia-related signaling in eukaryotic cells. Together, our results show, for the first time, a descriptive study reporting the relevance of epigenetic machinery in endothelial cells responding to cobalt-chromium, and it opens new perspectives to better understand their repercussions as prerequisites for driving cell adhesion, cell cycle progression, and angiogenesis surrounding this Co-Cr-based implantable device.

TET2 and LILRB1 mutations are frequent in Epstein-Barr virus-positive diffuse large B-cell lymphoma especially in elderly patients.

Diffuse large B-cell lymphoma (DLBCL) harboring Epstein-Barr virus (EBV) primarily occurs in patients who have underlying immunodeficiency or in elderly patients but is also reported in young, immunocompetent patients. The authors investigated the pathologic differences in EBV-positive DLBCL in these three groups of patients. In total, 57 patients with EBV-positive DLBCL were included in the study; of these, 16 patients had associated immunodeficiency, 10 were young (younger than 50years), and 31 were elderly (aged 50years or older). Immunostaining for CD8, CD68, PD-L1, and EBV nuclear antigen 2, and panel-based next-generation sequencing was performed on formalin-fixed, paraffin-embedded blocks. Immunohistochemistry revealed EBV nuclear antigen 2 positivity in 21 of the 49 patients. The degree of CD8-positive and CD68-positive immune cell infiltration and PD-L1 expression did not differ significantly in each group. Extranodal site involvement was more common in young patients (p=.021). In mutational analysis, the genes with the highest mutation frequency were PCLO (n=14), TET2 (n=10), and LILRB1 (n=10). For the TET2 gene, all 10 mutations were found in elderly patients (p=.007). Compared with a validation cohort, both TET2 and LILRB1 showed a higher mutation frequency in EBV-positive patients than in EBV-negative patients. EBV-positive DLBCL occurring in three different age and immune status groups showed similar pathologic characteristics. Notably, a high frequency of TET2 and LILRB1 mutations was characteristic of this disease in elderly patients. Further studies are needed to determine the role of TET2 and LILRB1 mutations in the development of EBV-positive DLBCL along with immune senescence. Epstein-Barr virus-positive diffuse large B-cell lymphoma occurring in three different groups (immunodeficiency-associated, young, and elderly) showed similar pathologic characteristics. The frequency of TET2 and LILRB1 mutations was high in elderly patients with Epstein-Barr virus-positive diffuse large B-cell lymphoma.

Myelodysplastic Syndrome associated TET2 mutations affect NK cell function and genome methylation

Myelodysplastic syndromes (MDS) are clonal hematopoietic disorders, representing high risk of progression to acute myeloid leukaemia, and frequently associated to somatic mutations, notably in the epigenetic regulator TET2. Natural Killer (NK) cells play a role in the anti-leukemic immune response via their cytolytic activity. Here we show that patients with MDS clones harbouring mutations in the TET2 gene are characterised by phenotypic defects in their circulating NK cells. Remarkably, NK cells and MDS clones from the same patient share the TET2 genotype, and the NK cells are characterised by increased methylation of genomic DNA and reduced expression of Killer Immunoglobulin-like receptors (KIR), perforin, and TNF-α. In vitro inhibition of TET2 in NK cells of healthy donors reduces their cytotoxicity, supporting its critical role in NK cell function. Conversely, NK cells from patients treated with azacytidine (#NCT02985190; https://clinicaltrials.gov/) show increased KIR and cytolytic protein expression, and IFN-γ production. Altogether, our findings show that, in addition to their oncogenic consequences in the myeloid cell subsets, TET2 mutations contribute to repressing NK-cell function in MDS patients.

Whole-exome sequencing reveals genetic variants in low-risk and high-risk neuroblastoma

This study aimed to investigate the genetic aberrations in neuroblastoma (NB) by comparing high and low-risk NB patients by whole-exome sequencing (WES) and to reveal the heterogeneity and association between somatic variants and clinical features. Seven NB patients with available clinical data were included in the study (4 in the low-risk group and 3 in the high-risk group). WES was performed and somatic variants associated with NB genes in the COSMIC database were selected through bioinformatics pipeline analysis. Variants were determined using the Integrative Genomics Viewer (IGV). Some gene variations were found in both groups, including variations in oncogene and tumor suppressor genes. In general, candidate gene variations were associated with chromatin remodeling complexes, the RAS pathway, cell proliferation, and DNA repair mechanism. Some variations in CSF1R, MSH6, PTPN11, SOX9, RET, TSC1, and DNMT1 genes were detected only in high-risk patients, while EP300, TET2, MYCN, PRDM1, and ARID2 gene variations were detected only in low-risk patients. When high-risk gene variants were compared with the cBioportal cancer genomic database, two common gene variants (ARID1A and NCOR2) were identified. However, when low-risk gene variants were compared with the cBioportal cancer genomic database, no common genes were found. GO/KEGG enrichment analysis was performed to find relevant biological processes and molecular pathways related to gene variants, which will help to decipher the molecular mechanisms of NB tumorigenesis and the phenotypic differences between high-risk and low-risk patients.

High nuclear expression of DNMT1 in correlation with inactivation of TET1 portray worst prognosis among the cervical carcinoma patients: clinical implications.

In this study, we aimed to understand the interplay of the epigenetic modifier genes DNMT1 and TET1 along with HPV infection in the cervical epithelium and how it changes during tumorigenesis. For this purpose, initially the bioinformatical analysis (methylation and expression profile) of DNMT1 and TET1 was analyzed in the TCGA dataset. Next genetic (deletion) and epigenetic profiling (promoter methylation) of DNMT1 and TET1 were done in our sample pool and also validated in CACX cell lines as well. The results were further correlated with different clinicopathological parameters. Our data revealed that HPV infection in basal/parabasal layers of cervical epithelium actually disrupts the epigenetic homeostasis of DNMT1 and TET1 proteins which ultimately leads to the high expression of DNMT1 along with further reduction in TET1 protein during the development of carcinoma. Further, in-depth look into the results revealed that comparatively low methylation frequency of DNMT1 coupled with high promoter methylation and deletion frequency [22-46%] of TET1 were the plausible reasons of their antagonistic expression profile during the progression of the disease. Interestingly, the prevalence of DNMT1 [9.1%] and TET1 promoter methylation [22.7%] found in both the plasma DNA of the respective CACX patients implicated its diagnostic importance in this study. Lastly, molecular alteration of TET1 alone or in combination with DNMT1 showed the worst overall survival among the patients. Hence, it may be concluded that an inverse molecular profile of DNMT1 and TET1 genes seen in the proliferative basal-parabasal layers of the cervical epithelium was aggravated during the development of CACX along with genetic and epigenetic changes due to HPV infection.

Distinct and opposite effects of leukemogenic Idh and Tet2 mutations in hematopoietic stem and progenitor cells

Mutations in IDH1, IDH2, and TET2 are recurrently observed in myeloid neoplasms. IDH1 and IDH2 encode isocitrate dehydrogenase isoforms, which normally catalyze the conversion of isocitrate to α-ketoglutarate (α-KG). Oncogenic IDH1/2 mutations confer neomorphic activity, leading to the production of D-2-hydroxyglutarate (D-2-HG), a potent inhibitor of α-KG-dependent enzymes which include the TET methylcytosine dioxygenases. Given their mutual exclusivity in myeloid neoplasms, IDH1, IDH2, and TET2 mutations may converge on a common oncogenic mechanism. Contrary to this expectation, we observed that they have distinct, and even opposite, effects on hematopoietic stem and progenitor cells in genetically engineered mice. Epigenetic and single-cell transcriptomic analyses revealed that Idh2R172K and Tet2 loss-of-function have divergent consequences on the expression and activity of key hematopoietic and leukemogenic regulators. Notably, chromatin accessibility and transcriptional deregulation in Idh2R172K cells were partially disconnected from DNA methylation alterations. These results highlight unanticipated divergent effects of IDH1/2 and TET2 mutations, providing support for the optimization of genotype-specific therapies.

Vitamin C boosts DNA demethylation in TET2 germline mutation carriers

BackgroundAccurate regulation of DNA methylation is necessary for normal cells to differentiate, develop and function. TET2 catalyzes stepwise DNA demethylation in hematopoietic cells. Mutations in the TET2 gene predispose to hematological malignancies by causing DNA methylation overload and aberrant epigenomic landscape. Studies on mice and cell lines show that the function of TET2 is boosted by vitamin C. Thus, by strengthening the demethylation activity of TET2, vitamin C could play a role in the prevention of hematological malignancies in individuals with TET2 dysfunction. We recently identified a family with lymphoma predisposition where a heterozygous truncating germline mutation in TET2 segregated with nodular lymphocyte-predominant Hodgkin lymphoma. The mutation carriers displayed a hypermethylation pattern that was absent in the family members without the mutation.MethodsIn a clinical trial of 1 year, we investigated the effects of oral 1 g/day vitamin C supplementation on DNA methylation by analyzing genome-wide DNA methylation and gene expression patterns from the family members.ResultsWe show that vitamin C reinforces the DNA demethylation cascade, reduces the proportion of hypermethylated loci and diminishes gene expression differences between TET2 mutation carriers and control individuals.ConclusionsThese results suggest that vitamin C supplementation increases DNA methylation turnover and provide a basis for further work to examine the potential benefits of vitamin C supplementation in individuals with germline and somatic TET2 mutations.Trial registration: This trial was registered at EudraCT with reference number of 2018-000155-41 (01.04.2019).Graphical

Molecular Genetics of Thrombotic Myeloproliferative Neoplasms: Implications in Precision Oncology.

Classical BCR-ABL-negative myeloproliferative neoplasms (MPN) include polycythaemia vera, essential thrombocythaemia, and primary myelofibrosis. Unlike monogenic disorders, a more complicated series of genetic mutations are believed to be responsible for MPN with various degrees of thromboembolic and bleeding complications. Thrombosis is one of the early manifestations in patients with MPN. To date, the driver genes responsible for MPN include JAK2, CALR, MPL, TET2, ASXL1, and MTHFR. Affords have been done to elucidate these mutations and the incidence of thromboembolic events. Several lines of evidence indicate that mutations in JAK2, MPL, TET2 and ASXL1 gene and polymorphisms in several clotting factors (GPIa, GPIIa, and GPIIIa) are associated with the occurrence and prevalence of thrombosis in MPN patients. Some polymorphisms within XRCC1, FBG, F2, F5, F7, F12, MMP9, HPA5, MTHFR, SDF-1, FAS, FASL, TERT, ACE, and TLR4 genes may also play a role in MPN manifestation. This review aims to provide an insightful overview on the genetic perspective of thrombotic complications in patients with MPN.

Methylomic change in TET1 and TET2 promoters is increased in children with acute lymphocytic leukemia

Objective: Methylomic changes have been recognized as essential contributors to the development of acute lymphocytic leukemia (ALL). While ALL has traditionally been considered a genetic disease, the increasing importance of epigenetic alterations in leukemogenesis has become evident. Here, our goal was to investigate the changes of DNA methylation level in ALL. Methods: To assess the DNA methylation pattern in ALL, we quantified gene expression of the methylation-related factors, including DNMTs, methionine synthase (MS), and the demethylation factors, TET gene family using qRT PCR. Results: The expression pattern of DNMTs, including DNMT1, DNMT3a, and DNMT3b, was markedly upregulated in samples derived from patients. On the contrary, the expression of the methyl creator, methionine synthase (MTR gene) was down-regulated in samples derived from children with ALL which revealed low concentration of vitamin B12 in their samples. The reduced expression of MTR in children with ALL reveals the disturbance of homocysteine and DNA methylation. Moreover, we examined the expression patterns of TET1, TET2, and TET3 genes implicated in the demethylation process. We found an evident decreasing level of TET1 and TET2 expression in ALL that may refer to an increasing DNA methylation activity in the promoter of the TET gene family. Conclusion: These data suggest the possible alteration in methyaltion-related factors due to methylomic changes within the promoter of TET1 and TET2 genes.

THE VALUE OF MUTATIONS IN THE ASXL1 GENE IN THE ONCOGENESIS OF ACUTE MYELOID LEUKEMIA IN ADULTS

The aim was to evaluate the significance of the ASXL1 gene mutations in the oncogenesis of acute myeloid leukemia (AML) in adults. Materials and methods. Bone marrow and peripheral blood samples of 49 patients with AML aged from 18 to 84 years, treated at the Sverdlovsk regional hematological center, were examined, including those with a morphological variant of AML M0 – 3, M1 – 4, M2 – 19, M3 – 6, M4 – 10, M5 – 1, M6 – 1, M7 – 1, blast plasmacytoid dendritic cell neoplasm – 1, acute hybrid leukemia – 2, AML after chronic myeloproliferative disease (CMPD) – 2. Mutations in the ASXL1 gene were detected in peripheral blood and bone marrow samples by direct RNA sequencing (n=26) and high-throughput DNA sequencing (n=23) on automatic genetic analyzers ABI Prism 310 and MiSeqDX, respectively. Results. It was found that pathogenetically significant mutations of the ASXL1 gene were detected in 16.3% of samples with AML M0, M2, M4, AML from CMPD and acute hybrid leukemia. The distribution of ASXL1 anomalies was as follows: deletion n. Del (1755;2007) — 4, duplication c.1934dupG — 3, non-synonymous transversion c.1348A>T — 1. Along with lesions of the ASXL1 gene, quantitative and structural chromosomal aberrations were determined in these samples, including del(5)(q13), t(8;21)(q22;q22), t(9;22)(q34;q11), as well as point mutations in the CEBPA, IDH2, NRAS, RUNX1, SRSF2, TET2 genes, internal tandem duplication in the FLT3 gene. This indicates the cooperation of two or more mutational events in the oncogenesis of ASXL1-positive AML, which can determine the different reaction of the tumor to chemotherapeutic treatment and the prognosis of the disease.

Tet1 deficiency exacerbates oxidative stress in acute kidney injury by regulating superoxide dismutase.

Rationale: Increased methylation of key genes has been observed in kidney diseases, suggesting that the ten-eleven translocation (Tet) methyl-cytosine dioxygenase family as well as 5mC oxidation may play important roles. As a member of the Tet family, the role of Tet1 in acute kidney injury (AKI) remains unclear. Methods: Tet1 knockout mice, with or without tempol treatment, a scavenger of reactive oxygen species (ROS), were challenged with ischemia and reperfusion (I/R) injury or unilateral ureteral obstruction (UUO) injury. RNA-sequencing, Western blotting, qRT-PCR, bisulfite sequencing, chromatin immunoprecipitation, immunohistochemical staining, and dot blot assays were performed. Results: Tet1 expression was rapidly upregulated following I/R or UUO injury. Moreover, Tet1 knockout mice showed increased renal injury and renal cell death, increased ROS accumulation, G2/M cell cycle arrest, inflammation, and fibrosis. Severe renal damage in injured Tet1 knockout mice was alleviated by tempol treatment. Mechanistically, Tet1 reduced the 5mC levels in an enzymatic activity-dependent manner on the promoters of Sod1 and Sod2 to promote their expression, thus lowering injury-induced excessive ROS and reducing I/R or UUO injury. Conclusions: Tet1 plays an important role in the development of AKI by promoting SOD expression through a DNA demethylase-dependent mechanism.

Defining the mutational profile of lower-risk myelodysplastic neoplasm patients with respect to disease progression using next-generation sequencing and pyrosequencing.

Lower-risk myelodysplastic neoplasms (LR-MDS) comprise the majority of MDS. Despite favourable prognoses, some patients remain at risk of rapid progression. We aimed to define the mutational profile of LR-MDS using next-generation sequencing (NGS), Sanger Sequencing (SSeq), and pyrosequencing. Samples from 5 primary LR-MDS (67 exons of SF3B1, U2AF1, SRSF2, ZRSR2, TET2, ASXL1, DNMT3A, TP53, and RUNX1 genes) were subjected to NGS. Next, a genomic study was performed to test for the presence of identified DNA sequence variants on a larger group of LR-MDS patients (25 bone marrow [BM], 3 saliva [SAL], and one peripheral blood [PB] sample/s). Both SSeq (all selected DNA sequence variants) and pyrosequencing (9 selected DNA sequence variants) were performed. Next-generation sequencing results identified 13 DNA sequence variants in 7 genes, comprising 8 mutations in 6 genes (ASXL1, DNMT3A, RUNX1, SF3B1, TET2, ZRSR2) in LR-MDS. The presence of 8 DNA variants was detected in the expanded LR-MDS group using SSeq and pyrosequencing. Mutation acquisition was observed during LR-MDS progression. Four LR-MDS and one acute myeloid leukaemia myelodysplasia-related patient exhibited the presence of at least one mutation. ASXL1 and SF3B1 alterations were most commonly observed (2 patients). Five DNA sequence variants detected in BM (patients: 9, 13) were also present in SAL. We suggest using NGS to determine the LR-MDS mutational profile at diagnosis and suspicion of disease progression. Moreover, PB and SAL molecular testing represent useful tools for monitoring LR-MDS at higher risk of progression. However, the results need to be confirmed in a larger group.

Dnmt1/Tet2-mediated changes in Cmip methylation regulate the development of nonalcoholic fatty liver disease by controlling the Gbp2-Pparγ-CD36 axis

Dynamic alteration of DNA methylation leads to various human diseases, including nonalcoholic fatty liver disease (NAFLD). Although C-Maf-inducing protein (Cmip) has been reported to be associated with NAFLD, its exact underlying mechanism remains unclear. Here, we aimed to elucidate this mechanism in NAFLD in vitro and in vivo. We first identified alterations in the methylation status of the Cmip intron 1 region in mouse liver tissues with high-fat high-sucrose diet-induced NAFLD. Knockdown of DNA methyltransferase (Dnmt) 1 significantly increased Cmip expression. Chromatin immunoprecipitation assays of AML12 cells treated with oleic and palmitic acid (OPA) revealed that Dnmt1 was dissociated and that methylation of H3K27me3 was significantly decreased in the Cmip intron 1 region. Conversely, the knockdown of Tet methylcytosine dioxygenase 2 (Tet2) decreased Cmip expression. Following OPA treatment, the CCCTC-binding factor (Ctcf) was recruited, and H3K4me3 was significantly hypermethylated. Intravenous Cmip siRNA injection ameliorated NAFLD pathogenic features in ob/ob mice. Additionally, Pparγ and Cd36 expression levels were dramatically decreased in the livers of ob/ob mice administered siCmip, and RNA sequencing revealed that Gbp2 was involved. Gbp2 knockdown also induced a decrease in Pparγ and Cd36 expression, resulting in the abrogation of fatty acid uptake into cells. Our data demonstrate that Cmip and Gbp2 expression levels are enhanced in human liver tissues bearing NAFLD features. We also show that Dnmt1–Trt2/Ctcf-mediated reversible modulation of Cmip methylation regulates the Gbp2–Pparγ–Cd36 signaling pathway, indicating the potential of Cmip as a novel therapeutic target for NAFLD.

Oxidative stress-induced TET1 upregulation mediates active DNA demethylation in human gastric epithelial cells.

The gastrointestinal (GI) tract is more vulnerable to effects by the outside environment, and experiences oxidative stress. A wide diversity of GI disorders can be partially attributed to oxidative stress. However, the mechanism of oxidative stress-caused GI pathological changes is not clear. In the present study, human gastric epithelial cells (hGECs) were treated with hydrogen peroxide (H2O2), and oxidative stress was determined. The effect of oxidative stress on the levels of some antioxidative enzymes, proliferation, nuclear DNA damage, apoptosis, expression of ten-eleven translocation (TET), and level of DNA methylation was determined in these cells. The results showed that H2O2 treatment caused oxidative stress, increased the levels of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA), decreased the level of glutathione (GSH), inhibited proliferation, caused nuclear DNA damage and apoptosis, upregulated the expression of TET1 gene, and ultimately led to active DNA demethylation in hGECs. The present study presents a mechanism by which oxidative stress induces active DNA demethylation in hGECs. We propose that TET inhibitors can be used to restore the oxidative stress-induced DNA demethylation, and thus inhibit possible malignant transformation of GI cells.

Clinical Implication of DNMT3A and TET2 Genes Mutations in Cytogenetically Normal Acute Myeloid Leukemia

Refining risk stratification of cytogenetically normal AML (CN-AML) cases is important for decision making and tailoring of therapy. In this context genetic and epigenetic mutations was considered. Among these epigenetic regulators are DNMT3A & TET2 genes. Therefore, the aim of this study was to determine the prevalence of DNMT3A and TET2 genes mutations and their impact on the outcome of adult AML patients. The present study is cross sectional study which was conducted on 39 adult CN-AML patients at diagnosis. For all included patients sanger sequencing was done for DNMT3A exon 23 and TET2 exon 3 genes. DNMT3A mutations were detected in 8 of 39 patients (20.5%), and in 5 of 39 patients(12.8%) in TET gene. Two CN-AML patients had combined mutations in both genes. All of the mutations detected were missense and only one was frame shift. Mutated TET2 or DNMT3A genes were significantly associated with failure of complete remission (CR) (p <0.001), higher mortality rate, shorter OS (mean=16 versus 22.7 months) and shorter DFS (mean= 9.5 versus 21.4 months) when compared to non-mutated ones. Mutated TET2 and DNMT3A detection define a subgroup of CN-AML patients with poor outcome.

Impact of neuroinflammation on epigenetic transcriptional control of Sonic Hedgehog members in the central nervous system

Sonic Hedgehog (Shh) signaling plays a critical role during central nervous system (CNS) development, and its dysregulation leads to neurological disorders. Nevertheless, little is known about Shh signaling regulation in the adult brain. Here, we investigated the contribution of DNA methylation on the transcriptional control of Shh signaling pathway members and its basal distribution impact on the brain, as well as its modulation by inflammation. The methylation status of the promoter regions of these members and the transcriptional profile of DNA-modifying enzymes (DNA Methyltransferases – DNMTs and Tet Methylcytosine Dioxygenase – TETs) were investigated in a murine model of neuroinflammation by qPCR. We showed that, in the adult brain, methylation in the CpG promoter regions of the Shh signaling pathway members was critical to determine the endogenous differential transcriptional pattern observed between distinct brain regions. We also found that neuroinflammation differentially modulates gene expression of DNA-modifying enzymes. This study reveals the basal transcriptional profile of DNMTs and TETs enzymes in the CNS and demonstrates the effect of neuroinflammation on the transcriptional control of members of the Shh Signaling pathway in the adult brain.

Gene Mutation and Clinical Characteristics of Patients with Acute Leukemia

To investigate the characteristics of gene mutation, clinical characteristics and significance in acute leukemia (AL) patients. The clinical data of 102 AL patients in Hebei General Hospital from September 2016 to September 2020 were collected and analyzed retrospectively, including the characteristics of gene mutation, age, peripheral blood cells, bone marrow blasts, leukemia subtypes and myeloperoxidase (MPO). The total gene mutation rate was 87.25% (89/102) in all 102 patients. A total of 275 gene mutations were detected, with an average of 2.70 gene mutations per patient. The most frequent mutations of 102 patients were as follows: CEBPA (6.91%), NPM1 and ASXL1(6.18%), TET2 (5.82%), DNMT3A (5.45%), IDH2 and FLT3-ITD (5.09%). Gene mutations often occurred simultaneously. CEBPA mutation occurred in 10 cases of M2 subtype, while TET2 mutation occurred in 9 cases of M2 subtype. Among the most common gene mutations in MPO low expression group, mutation rates of NPM1, DNMT3A, IDH2, SF related gene mutation and RUNX1 were significantly different than those in MPO high expression group (all P<0.05). Univariate analysis showed that age, NPM1, DNMT3A and FLT3-ITD had significant effects on leukocyte level. Logistic regression analysis showed that patients with positive NPM1 mutations may had higher leukocyte levels (p=0.038), and those with positive DNMT3A mutations may had higher platelet levels (p=0.042). The incidence of gene mutation in patients with AL is high, and it often occurs simultaneously. CEBPA and TET2 gene mutations are more common in M2 subtype. In patients with MPO low expression, the most common gene mutations are NPM1, DNMT3A and IDH2. AL patients with NPM1 gene mutation had higher white blood cell levels, while with DNMT3A gene mutation had higher platelet levels.

A postpartum enriched environment rescues impaired cognition and oxidative markers in aged mice with gestational inflammation.

Previous studies have shown that gestational inflammation can accelerate age-associated cognitive decline (AACD) in maternal mice; enriched environments (EEs) have been reported to protect normally aging mice from AACD and improve mitochondrial function. However, it is unclear whether the nitrosative stress-related proteins tet methylcytosine dioxygenase 1 (TET1) and S-nitrosoglutathione reductase (GSNOR) are involved in the accelerated aging process of gestational inflammation and whether EEs can slow this process. In this study, CD-1 female mice on the 15th day of pregnancy were injected with bacterial lipopolysaccharide (50μg/kg; LPS group) or an equivalent amount of normal saline (CON group) from the abdominal cavity for 4 consecutive days. Twenty-one days after delivery, half of the LPS-treated mice were randomly selected for EE until the end of the behavioral experiment (LPS-E group). When the female rats were raised to 6 months and 18 months of age, the Morris water maze (MWM) was used to detect spatial learning and memory ability; RT-PCR and Western blots were used to measure the mRNA and protein levels of hippocampal TET1 and GSNOR. As for the control group, compared with 6-month-old mice, the spatial learning and memory ability of 18-month-old mice decreased, and the hippocampal TET1 and GSNOR mRNA and protein levels were decreased. Gestational inflammation exacerbated these age-related changes, but an EE alleviated the effects. Pearson's correlation analysis indicated that performance during the learning and memory periods in the MWM correlated with the levels of hippocampal TET1 and GSNOR. Our findings suggest that gestational inflammation accelerates age-related learning and memory impairments and that postpartum EE exposure could alleviate these changes. These effects may be related to hippocampal TET1 and GSNOR expression.